From: Edward Cranswick Subject: Re: Reply (seismology and human consequences) Date: Tue, 30 Sep 1997 15:20:15 -0600 Stephen- I think that your recent correspondence (see excerpt below) about our seismological interest in earthquakes as opposed to their impact on human life has raised some very interesting and important issues that are useful to discuss. I know that when we (the USGS) chase large and damaging earthquakes, e.g., the 1988 Spitak Earthquake in Armenia, our focus on the technical aspects can keep us from being lost in the tragedy, i.e., the death of 1% of the population of Armenia. Alternatively, I remember spending the first few days after the 1994 Northridge Earthquake in California trying to whip our portable autonomous digital seismographs into shape. One afternoon we were on the UC Northridge campus, and if one looked around, one could see some building damage and the traffic lights near the campus that weren't functioning. But then abruptly at 4:00 PM, the lawn sprinklers turned on automatically all around us, but we still couldn't get the damn seismograph to work. In general, I agree with Barry Lotz, "that in the majority of cases that I can think of 'structures kill people not earthquakes'. I consider earthquakes part of the heartbeat of the planet. We have stethoscopes." We make the structures, and we should not forget our responsibility for that. Rather than think that "a good calibration may be bought at the expense of lives and homes", it is much better to think that those people and their dwellings did not die, were not destroyed, in vain, as is often the case. In many cases, the only record of ground motion we have is the damage done or not done to a structure. There were about 150,000 buildings inspected for damage after the Northridge Earthquake, about 20,000 were yellow- and red-tagged (designated as significantly or severely damaged), but the mainshock was locally recorded on scale by only about 200 strong motion accelerometers. So in most cases, in considering why the building on one side of the street collapsed, but the one on the other side did not, we don't know if the building collapsed because of strong ground shaking or because of structural flaws. In my early notion of the PSN, I visualized every house having a combination strong groundmotion accelerometer/ seismograph -- similar to all houses having smoke detectors -- and these cheap, standardized instruments would be calibrated. We need more reliable calibrations. Our old way of calibrating seismographs was with underground nuclear explosions. Prior to the late 1950's, before the US Air Force realized you could detect Soviet nuclear tests with seismographs, seismology was the domain of a handful of international scientists, but then it became Big Business (in terms of scientific funding). That was when calibration became a real important issue, and bombs were the best source of calibration. But if we can't respond to earthquakes which generate much of their energy in the frequency band to which the human nervous system is most sensitive, 1.0-20 Hz, how can we be aware of the really significant threats we face that have much longer time constants, such as global warming and environmental degradation? Barry says we have "stethoscopes" which allow us to hear the small, everyday seismic motions of the Earth above the extraordinary din of cultural noise we create, and this reminds us that She is alive and well. But as Bob Dylan said, "you don't need a weatherman to know which way the wind blows"; Los Angeles has a problem with too little water and gas and too many people; the problem with the place is as much the freeways as the earthquakes, and we are responsible for the former. Earthquakes are a voice that reminds us of our human position in the Cosmos. -Edward Stephen Paul wrote: .... > I am glad that you do think of the result as something other than a blip on > the screen. I live in LA, and when we have a major event here, well, it's > not real pretty. I look at a condemned building every day that was an > apartment bldg. before our last shaker, and I look at it out the window of > my office. There but for the Grace of God went we. And until those > stethoscopes can get people out in time, (which day must surely come, and > that is exactly why these lists have my full support), I do think it is > important to remember that a good calibration may be bought at the expense > of lives and homes. -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: Reply (seismology and human consequences) Date: Tue, 30 Sep 1997 17:27:17 -0500 Edward Cranswick wrote: > In my early notion of the PSN, I visualized every house having a > combination strong groundmotion accelerometer/ seismograph -- similar to > all houses having smoke detectors -- and these cheap, standardized > instruments would be calibrated. We need more reliable calibrations. There has been a lot of discussion of some sort of instrument to meet these needs. This comment reminds me of an instrument that I heard about years ago. While in school I had a summer job working for a small engineering firm in St. Louis. One of the things they did was to read data from a mechanical strain gage. This device was used to measure the traffic stress on bridges and I think in aircraft structures during flight tests. It was attached to a structural member of the bridge or aircraft and recorded stress as series of scratches on a small polished brass washer. The device was quite small and purely mechanical, it could remain in place for years and record the major flexures of the structural member it was attached to. It seems that such a device could supply at least part of the picture during a major quake. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: bzimmerman@............ Subject: Image maps Date: Tue, 30 Sep 1997 20:47:17 -0500 (EST) I seem to remember a post from someone offering to produce image maps of quake locations from a table of latitudes and longitudes. Are you still out there? Or does anyone remember the post? Can't seem to find it in the archives. What I'm looking for is the DOS program that does this. It would be nice to be able to easily update my own maps. Brian Zimmerman _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: wb6nvo@............. (Jim Skinner) Subject: Re: Decoding with sound card. Date: Tue, 30 Sep 1997 17:58:29 -0700 (MST) > >I was thinking about making an earthquake alarm using the remote SN. >I plan to use a frequency to voltage converter and set the alarm to >trigger when there is a pre-set voltage difference. Does anyone have any >thoughts on this? If distant enough, it may be used as a warning! > >Thanks, >Peter Fleming >alarm@........... > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > - Peter- I used one (actually several ) for "house alarms" for a number of years... they work great!!! One caution; don't pick one that goes through its autocal routines during the times you would prefer to be sleeping. A cheap and simple way to use one is to make/buy an audio filter and notch out the pilot tone. By varying the selectivity,etc you can actually dial an event of what ever size you want to hear...real easy to set up with an audio sig-gen. Jim Skinner _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: 2.5 event @ Manassas, VA Date: Tue, 30 Sep 1997 21:40:38 -0600 Bob- Very nice record! (reminds me of home: I spent 4 years in graduate school studying East Coast earthquakes). -Edward RLLaney@....... wrote: > > The attached event file is for the subject quake on September 29, 1997. This > is my first submission of an event, so please let me know if additional > information is needed. > > Thank you. > > Bob Laney > > --------------------------------------------------------------- > > Name: 970929B.RL1 > Part 1.2 Type: unspecified type (application/octet-stream) > Encoding: base64 -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: More on SG sensor testing. Date: Tue, 30 Sep 1997 22:29:22 -0600 Larry- These are the poles and zeroes of the complex transfer function of the sensor (which I can't help much with) but that does not tell you what the site response transfer function is; or better yet, what the ratio of your site response to that of Berkeley's is. I am still cranking on the file conversion from SDAS (Ted Blank, i.e., PSN) format to DR100 Format with the info you gave me, and this may permit a comparison of site responses. -Edward Larry Cochrane wrote: > > At 09:10 AM 9/24/97 -0400, you wrote: > >Larry, > > I'm reading the e-mail which accumulated during a vacation in Los Alamos > >where my daughter is doing a post-doc in microbiology at the labs. (If you > >want to read some weird stuff, try her web page > >www-ls.lanl.gov/~sbarns/crenarchaeota.html The www-ls is correct but was > >something new to me.) Had a fine time-rode the narrow-gage train from > >Durango to Silverton (CO) again, a trip I can recommend. > > Your daughters research looks very interesting.... > > > I found your shake table work and the subsequent messages very > >interesting. The use of a stepping motor was a slick idea. A few comments > >about your comparison of the SG and Berkeley broadband seismograms:You > >compare them on the basis of peak-to-peak counts. I suggest that the > >comparison would be more meaningful if it was in terms of actual > >velocities, e. g., nanometers/sec. This is what I did in my write-up on > >the meter-movement calibrator for the Lehman. > > The biggest problem with my test was I didn't know how much the table was > moving. Since I was interested in freq. I didn't think it mattered, and, I > don't have the equipment to accurately measure the small movement. > > For the Berkeley seismometer I have the following response information: > > # > # ======== CHANNEL RESPONSE DATA ======== > B050F03 Station: BKS > B050F16 Network: BK > B052F04 Channel: BHN > B052F22 Start date: 1993,348,00:00 > B052F23 End date: No Ending Time > # ======================================= > # + +--------------------------------------------+ > + > # + | Response (Poles & Zeros), BKS ch BHN | > + > # + +--------------------------------------------+ > + > # > B053F03 Transfer function type: A [Laplace Transform > (Rad/sec)] > B053F04 Stage sequence number: 1 > B053F05 Response in units lookup: M/S - Velocity in Meters > Per Second > B053F06 Response out units lookup: V - Volts > B053F07 A0 normalization factor: 987.14 > B053F08 Normalization frequency: 0.02 > B053F09 Number of zeroes: 2 > B053F14 Number of poles: 4 > # Complex zeroes: > # i real imag real_error imag_error > B053F10-13 0 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 > B053F10-13 1 0.000000E+00 0.000000E+00 0.000000E+00 0.000000E+00 > # Complex poles: > # i real imag real_error imag_error > B053F15-18 0 -1.234120E-02 1.234150E-02 0.000000E+00 0.000000E+00 > B053F15-18 1 -1.234120E-02 -1.234150E-02 0.000000E+00 0.000000E+00 > B053F15-18 2 -1.958780E+01 2.456170E+01 0.000000E+00 0.000000E+00 > B053F15-18 3 -1.958780E+01 -2.456170E+01 0.000000E+00 0.000000E+00 > # > # + +-------------------------------------------+ > + > # + | Response (Coefficients), BKS ch BHN | > + > # + +-------------------------------------------+ > + > # > B054F03 Transfer function type: D > B054F04 Stage sequence number: 2 > B054F05 Response in units lookup: V - Volts > B054F06 Response out units lookup: COUNTS - Digital Counts > B054F07 Number of numerators: 51 > B054F10 Number of denominators: 0 > # Numerator coefficients: > # i, coefficient, error > B054F08-09 0 -3.777910E-08 -7.555820E-10 > B054F08-09 1 -4.148830E-07 -8.297660E-09 > B054F08-09 2 9.445450E-06 1.889090E-07 > B054F08-09 3 3.370620E-05 6.741250E-07 > B054F08-09 4 -2.429500E-05 -4.859010E-07 > B054F08-09 5 1.960520E-05 3.921050E-07 > B054F08-09 6 1.544480E-06 3.088960E-08 > B054F08-09 7 -2.150600E-05 -4.301210E-07 > B054F08-09 8 2.705530E-05 5.411070E-07 > B054F08-09 9 -1.676900E-05 -3.353810E-07 > B054F08-09 10 5.124170E-03 1.024830E-04 > B054F08-09 11 1.779800E-03 3.559600E-05 > B054F08-09 12 -4.332210E-03 -8.664430E-05 > B054F08-09 13 7.430310E-03 1.486060E-04 > B054F08-09 14 -1.039340E-02 -2.078670E-04 > B054F08-09 15 1.183280E-02 2.366560E-04 > B054F08-09 16 -1.055880E-02 -2.111760E-04 > B054F08-09 17 6.859030E-03 1.371810E-04 > B054F08-09 18 1.163370E-02 2.326740E-04 > B054F08-09 19 -2.604490E-02 -5.208970E-04 > B054F08-09 20 4.648550E-02 9.297090E-04 > B054F08-09 21 -7.015840E-02 -1.403170E-03 > B054F08-09 22 9.522160E-02 1.904430E-03 > B054F08-09 23 -1.275080E-01 -2.550170E-03 > B054F08-09 24 1.436970E-01 2.873940E-03 > B054F08-09 25 8.778300E-01 1.755660E-02 > B054F08-09 26 8.819290E-02 1.763860E-03 > B054F08-09 27 -1.059150E-01 -2.118300E-03 > B054F08-09 28 8.731180E-02 1.746240E-03 > B054F08-09 29 -6.899650E-02 -1.379930E-03 > B054F08-09 30 4.899210E-02 9.798410E-04 > B054F08-09 31 -3.020580E-02 -6.041160E-04 > B054F08-09 32 1.640370E-02 3.280730E-04 > B054F08-09 33 2.733980E-03 5.467960E-05 > B054F08-09 34 -7.899160E-03 -1.579830E-04 > B054F08-09 35 1.036420E-02 2.072840E-04 > B054F08-09 36 -9.902790E-03 -1.980560E-04 > B054F08-09 37 7.607170E-03 1.521430E-04 > B054F08-09 38 -4.881500E-03 -9.763010E-05 > B054F08-09 39 2.557260E-03 5.114520E-05 > B054F08-09 40 4.751230E-03 9.502450E-05 > B054F08-09 41 -8.744070E-05 -1.748810E-06 > B054F08-09 42 3.545030E-05 7.090060E-07 > B054F08-09 43 -3.244920E-05 -6.489850E-07 > B054F08-09 44 9.078710E-06 1.815740E-07 > B054F08-09 45 1.395880E-05 2.791750E-07 > B054F08-09 46 -2.044260E-05 -4.088520E-07 > B054F08-09 47 3.442010E-05 6.884020E-07 > B054F08-09 48 7.743230E-06 1.548650E-07 > B054F08-09 49 -3.925280E-07 -7.850560E-09 > B054F08-09 50 -2.914360E-08 -5.828710E-10 > # > # + +---------------------------------------+ > + > # + | Channel Sensitivity, BKS ch BHN | > + > # + +---------------------------------------+ > + > # > B058F03 Stage sequence number: 0 > B058F04 Sensitivity: 1.047200E+09 > B058F05 Frequency of sensitivity: 2.000000E-02 HZ > B058F06 Number of calibrations: 0 > # > > Unfortunately I have no idea on how to read this... If someone does, please > let me know. > > -Larry > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: dean sevold Subject: Sound cards Date: Tue, 30 Sep 97 14:24:42 PDT All: Soundblaster has a large file for use with the SB boards; its the Sound = Blaster Dos Developers Kit,and includes drivers in most programming langu= ages. Soundblaster can be reached at http://www.creaf.com . _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Date: Tue, 30 Sep 1997 10:10:48 -0700 From: Norman Davis WB6SHI Subject: Re: Decoding with sound card. Date: Tue, 30 Sep 1997 19:57:05 >>I was thinking about making an earthquake alarm using the remote SN. >>I plan to use a frequency to voltage converter and set the alarm to >>trigger when there is a pre-set voltage difference. Does anyone have any >>thoughts on this? If distant enough, it may be used as a warning! I did too. I had a pll tuned to the pilot tone and when it changed freq I had it open a speaker so I could hear the tone. It worked great but drove the wife nuts cuz we had some RFI that would hit it some times and when the pilot tone droped the squelch would open and set the thing off. Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Image maps Date: Thu, 2 Oct 1997 09:44:07 -0400 Brian Zimmerman, Yes, I did (and still do) offer to make a world map of your 'quakes if you supply a list of lats & lons. I use a rather involved process using a CAD (computer aided design) progr= am called DesignCAD. This is about $300. It included a BASIC-like programming language which = I use to read data files and plot points. If you have something like this,= I can supply the x-y pairs which draw the map and you can plot your own 'quakes. If you want to send me your 'quakes, make an ASCII file of lats & lons separated by a comma with one lat-lon pair per line. Include only lats &= lons, not magnitudes or other stuff. Bob Barns = _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: David A Nelson Subject: Re: Image maps Date: Fri, 03 Oct 1997 01:57:46 +1200 Bob, brian was looking for a way to plot the quakes on a relief map basically the same as I used for the PSN world map I supplied him with the map earlier in the week it would be great if there was a prog available that any map could be loaded into and then have the data plotted onto it Dave At 09:44 AM 10/2/97 -0400, you wrote: >Brian Zimmerman, > Yes, I did (and still do) offer to make a world map of your 'quakes if >you supply a list of lats & lons. >I use a rather involved process using a CAD (computer aided design) program >called DesignCAD. >This is about $300. It included a BASIC-like programming language which I >use to read data files and plot points. If you have something like this, I >can supply the x-y pairs which draw the map and you can plot your own >'quakes. > If you want to send me your 'quakes, make an ASCII file of lats & lons >separated by a comma with one lat-lon pair per line. Include only lats & >lons, not magnitudes or other stuff. >Bob Barns > > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Don Rose Subject: Re: Image maps Date: Thu, 02 Oct 1997 09:03:37 -0700 Robert L Barns wrote: > > Brian Zimmerman, > Yes, I did (and still do) offer to make a world map of your 'quakes if > you supply a list of lats & lons. > I use a rather involved process using a CAD (computer aided design) program > called DesignCAD. > This is about $300. It included a BASIC-like programming language which I > use to read data files and plot points. If you have something like this, I > can supply the x-y pairs which draw the map and you can plot your own > 'quakes. > If you want to send me your 'quakes, make an ASCII file of lats & lons > separated by a comma with one lat-lon pair per line. Include only lats & > lons, not magnitudes or other stuff. > Bob Barns > > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L please delete me from the list. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: GeE777@....... Subject: Re: Image maps Date: Thu, 2 Oct 1997 14:14:52 -0400 (EDT) Have you looked into -- DeLorme Mapping Lower Main Street, P.O.Box 298 Freeport, ME 04032 USA Telephone (207)865-1234 It comes on a CD Rom George << n a message dated 97-10-02 10:03:41 EDT, you write: Bob, brian was looking for a way to plot the quakes on a relief map basically the same as I used for the PSN world map I supplied him with the map earlier in the week it would be great if there was a prog available that any map could be loaded into and then have the data plotted onto it Dave >> _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Trigger alogorithm Date: Thu, 02 Oct 1997 13:56:31 -0600 Barry- I couldn't follow the your frequency domain detection (trigger) algorithm in detail without having to think, which is a problem for me, but I am wondering why you triggering in realtime rather than recording continuously and then detecting by post processing and/or by correlation with a catalog of events from CalNet, NEIC, etc. -Edward barry lotz wrote: > > To All > I have been trying for a while to develope a "better" event triggering > routine for my system. The hope is to be able to detect teleseismic and > small local events in a noisy environment. I currently work in a trigger > environment rather than a continuous recording one. I'll try to describe > what I've been up to. > My detection routine is based on that described by Goforth & Herrin in > BSSA vol 71,no 4 , Aug 1981."An Automatic Seismic Signal Detection Algorithm > Based on the Walsh Transform". The basic description of the routine is as > follows. A window of data is acquired (in my system, 512 readings). A > transform is performed to convert this data to the frequency domain. G & H > used a Walsh transform for speed ,at a time when processors were slower. I > tried The Walsh routine and it definitely was faster but it produces aliases. > I use a 512 point FFT. The individual frequency magnitudes of the spectrum > are then summed. If one does not want to include a particular frequency it > can be avoided in the summing process. This weighted sum is stored as the > newest entry in a 512 point sequence of sums. The oldest sum is also > deleted at this time. The 512 entries are then sorted by size and the 75th % > sum is compared to the 50th % sum. A trigger threshold is obtained from the > following equation: Threshold = median + K*( 75% - median). K is a constant > which is in the range of 3-5. The current sum is then compared with this > continously varing threshold. If the current sum exceeds the threshold an > event is triggered. If the sum does not exceed the threshold it is saved and > another 512 points of data are acquired and the process is repeated.Actually > the window is 480 points of new data, I used an overlapping window of 32 > points. Because of transients, I wait to have 7-8 sums in sequence before I > trigger an event. I continue to save data, once the trigger is initiated, > until the FFT sum falls below the threshold. I then save the event to a > file. Because of lost P & S waves I keep two revolving 2k to 4k buffers > which are saved in front of the first trigger point( like Ted Blank's EMON). > I currently run the system at 8 hz just for teleseismic events. It has > helped me to detect events which I couldn't possibly have done before ,ie. > I can crank the gain up quite a bit. The only real problem I have had to > date has been with wind and trees. Wind gusts are transient noise in the > frequency range I am interested in. They don't trigger an event due to their > short duration but over time they raise the threshold so high that real > events can slip by. This winter will help the learning curve. I'll keep you > posted. I hope I haven't been to confusing. > > PS > > I have a FIR digital filter in the routine and have used it with limited > success. I can't get IIR filters to be stable over time. > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: Decoding Date: Thu, 02 Oct 1997 17:15:44 -0500 Phil Giannini wrote: > > My > question is, does anybody know if there is a way to take a PSN file recorded > on SDR and turn it into a file that can be read by a sound card in the same > manner as the Landers quake was. > This question got me going. I have also wanted to listen to quakes. I did a little web browsing and found a shareware program Cool Edit 96 http://www.syntrillium.com/load.htm for those who use Win95 or NT this program will let you listen to files in PSN event file format. Since except for the header the data in the file is recorded as 16 bit PCM. Just ask Cool Edit to open "all files" and tell it 16 bit mono PCM and pick a sampling rate that sounds good. You will have to ignore or edit off the header data at the beginning of the file. You can then save the file in .au, .wav or your choice of audio formats. I converted one of Larry's files and put it on my web page at http://soli.inav.net/~jmhannon/seismology.html Click on Listen to an Earthquake. I started writing a File filter for Col Edit that would read PSN files and remove the header info but there is a small problem with the use of using the file extension to identify stations and Microsoft's use of extension to identify file types. Cool Edit only lets you put 4 different file extensions in a filter. So you would have to rename files to one of the extensions in the filter for it to work. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Caruso Subject: Re: Image maps Date: Thu, 2 Oct 1997 20:29:23 -0400 (EDT) If you have windows 95 you can download software called imaging from microsoft imaging and edit faxes and images... so then download a map and edit it! STEPHEN CARUSO CET KB8UGH _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: Trigger alogorithm Date: Thu, 02 Oct 1997 09:20:47 -0700 Edward I guess because it's a challange. I thinks it also gives me a better understanding of how the event is composed. It also would be useful to me in a remote, "quiet" site with limited memory capacity. I don't know... maybe also because it's there. :-} Barry Edward Cranswick wrote: > > Barry- > I couldn't follow the your frequency domain detection (trigger) > algorithm in detail without having to think, which is a problem for me, > but I am wondering why you triggering in realtime rather than recording > continuously and then detecting by post processing and/or by correlation > with a catalog of events from CalNet, NEIC, etc. > -Edward > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Caruso Subject: Manassas quake? Area history? Date: Fri, 3 Oct 1997 21:44:09 -0400 (EDT) I was told there was an earthquake in VA recently. Did anybody see this one? It was 2.5. Does Va get many ever? STEPHEN CARUSO CET KB8UGH _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Caruso Subject: Re: Manassas quake? Area history? Date: Fri, 3 Oct 1997 21:48:23 -0400 (EDT) 1:30 est 17:30 uct STEPHEN CARUSO CET KB8UGH _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: George Bush Subject: Wow, what was that Date: Sat, 04 Oct 1997 08:36:20 -0700 Did anyone else detect a large event at about 11:00 UT 10/4/97? My digitizing system is off-line, but the drum recorder pen went stop-to-stop. The event lasted about 15 minutes, so was not nearby, but also was probably not on the other side of the world. I really miss being able to use winquake to tell how far away the event was. George Bush Sea Ranch, CA 38.74, -123.5 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Marnie Gannon Subject: Re: Wow, what was that Date: Sat, 04 Oct 1997 09:52:00 -0700 George Bush wrote: > > Did anyone else detect a large event at about 11:00 UT 10/4/97? My > digitizing system is off-line, but the drum recorder pen went stop-to-stop. > The event lasted about 15 minutes, so was not nearby, but also was probably > not on the other side of the world. > > I really miss being able to use winquake to tell how far away the event was. > > George Bush > Sea Ranch, CA > 38.74, -123.5 > e0725c0-s- r n USGS-EARTHQUAKE-REPORT 10-04 0313 EARTHQUAKE REPORT == PRELIMINARY EARTHQUAKE REPORT == Rapid Earthquake Location Service U.S. Geological Survey, Menlo Park, California U.C. Berkeley Seismographic Stations, Berkeley, California Version 2: Updates lower and earlier versions of this earthquake report This event has been reviewed by David Oppenheimer-USGS A MODERATE EARTHQUAKE OCCURRED AT 03:57 AM PDT Saturday, Oct 04, 1997. THE MAGNITUDE 5.1 (ML) EVENT IS LOCATED 67 MILES W OF TRINIDAD, CA THE HYPOCENTRAL DEPTH IS 4.9 MILES. N.B. This earthquake occurs outside our network. The location is probably uncertain by 10 km and the depth is currently indeterminate. PRINCIPAL EARTHQUAKE PARAMETERS _______________________________ Magnitude : 5.12 ML Event Date & Time : 10/04/1997 03:57:33 AM PDT 10/04/1997 10:57:33 UTC Location : 41.0448 N, 125.4258 W : (41 deg. 2.69 min. N, 125 deg. 25.55 min. W) Depth : 7.9 km. deep ( 4.9 miles) Location Quality : Poor 108 km ( 67 miles) W (270 degrees) of Trinidad, CA 109 km ( 68 miles) WNW (285 degrees) of Eureka, CA 111 km ( 69 miles) WNW (298 degrees) of Ferndale, CA 112 km ( 69 miles) W (276 degrees) of McKinleyville, CA 115 km ( 71 miles) W (280 degrees) of Arcata, CA ADDITIONAL EARTHQUAKE PARAMETERS ________________________________ number of phases : 215 rms misfit : 0.39 seconds horizontal location error : 1.6 km vertical location error : 33.1 km maximum azimuthal gap : 236 degrees distance to nearest station : 112. km In region 2 (070) PACIFIC OCEAN event ID: 1020477 ====================================================================== ==== U.S. Geological Survey | Seismographic Station Seismology Section | 475 McCone Hall 345 Middlefield Road - MS 977 | U.C. Berkeley Menlo Park, CA 94025 | Berkeley, CA 94720- 4760 Voice : 415-329-4085 | 510-642-3977 Earthquake Info : 415-329-4025 | 510-642-2160 Fax : 415-329-5163 | 510-643-5811 E-mail : ncsn@................... | bdsn@................ edu More Information about this event and other earthquakes is available on the Worldwide Web at http://quake.wr.usgs.gov EDIS-10-04-97 0426 PDT _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: lahr@................. (Dr. John Lahr (USGS-GI Seismologist)) Subject: Re: Image maps Date: Sat, 4 Oct 1997 11:33:48 -0800 There is a program available on the web called Seismic that can plot earthquake epicenters on a map, in cross section, or in 3-D view. It actually plots them one at a time in speeded up time so that you see the pattern of seismicity as it develops over time. The program comes with a global data set and shaded relief background maps for the entire world and for many sub-regions of the world. It also includes a program that can convert from various formats into the ".hy3" format used for its earthquake data sets. There are far too many features to describe in detail here. For more information on Seismic, check out Alan Jones' home page at: http://sunquakes.geol.binghamton.edu/faculty/jones/ The current version of the program is called Seismic/Eruption, as it also displays volcanic eruptions as they occur. This program, and another called Seismic/Waves are included in a new exhibit at the Smithsonian in Washington. Seismic/Waves is a neat program that shows seismic wave fronts as they move outward from an earthquake's hypocenter. These are shown graphically on a cross section of the earth, so one can see how the structure of the earth produces reflection, refractions, and shadow zones. On the top of the screen, one sees an actual seismic record with the phases identified. The programs are free, but a $30 registration fee is requested if you enjoy using them. For teachers and students in K-12, registration is not requested. JCLahr ################################## John C. Lahr ################################# Seismologist ################################ U.S. Geological Survey ############################### c/o Geophysical Institute ############################## 903 Koyukuk Drive ~~~~~~~~~~~~~~ Get ~~~~~~~~~~ ############################# ########################################################### P.O. Box 757320 ################################ Fairbanks, AK 99775 ################################# Phone: (907) 474-7997 ################################## Fax: (907) 474-5618 ~~~~~~~~ the thrust? ~~~~~~~~~~~~~~ lahr@........ #################################### http://www.aeic.alaska.edu/Input/lahr/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: new event Date: Sat, 04 Oct 1997 06:53:13 -0700 All Looks like something coming thru @ 01:37 UTC 10/05. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: David A Nelson Subject: Re: new event Date: Sun, 05 Oct 1997 14:22:32 +1200 how's it look barry, was it an aftershk to the offshore cal. 5.1 ?? Dave At 06:53 AM 10/4/97 -0700, you wrote: >All > Looks like something coming thru @ 01:37 UTC 10/05. > Barry > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: new event Date: Sat, 04 Oct 1997 07:57:39 -0700 David Weird. Maybe it's my washing machine. :-]. I'll upload it. Barry David A Nelson wrote: > > how's it look barry, was it an aftershk to the offshore cal. 5.1 ?? > > Dave > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: David A Nelson Subject: Re: new event Date: Sun, 05 Oct 1997 15:07:32 +1200 well barry, never seen anything like that before the mind boggles !!! Dave At 07:57 AM 10/4/97 -0700, you wrote: >David > Weird. Maybe it's my washing machine. :-]. I'll upload it. > Barry > >David A Nelson wrote: >> >> how's it look barry, was it an aftershk to the offshore cal. 5.1 ?? >> >> Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Dott. Roberto E. Pozzo" Subject: PSN Italy works ! Date: Sun, 05 Oct 1997 13:03:57 +0200 Dear Larry C.,Edward C. and all PSN guys . PSN ITALY is now a reality ! Few days ago, as you know, in Central Italy two earthquakes (5.5 and 5.9 followed by more than 90 aftershocks) have caused 6 victims, about 120 injuried and more of 5000 homeless).The famous S. Francesco Church in Assisi also has suffered very serious damages ( a part of a Cimabue's masterpiece is forever lost ) . Francesco,Giovanni and I are keeping in touch H24 by phone and we exchange our wq recordings daily for study proposals. This in the spirit of P.S.N. and the first really well-working collaboration between amateurs in seismology in Italy during a seismic period. Count on us ! roberto _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: mark widerstrom Subject: Re: Cost for seismograph Date: Sun, 05 Oct 1997 07:04:30 -0500 Anyone have the costs involved with doing a seismograph? I see alot of portable units but something not pocket eating would be appreciated. I am a ham radio operator and im looking at frequencies above 16 mhz that could be reading seismo triggers. Thanks for your time Markww in Houston Texas N5UOA Support your local disabled veterans units. Anyone have the costs involved with doing a seismograph?  I see alot of portable units but something not pocket eating would be appreciated.  I am a ham radio operator and im looking at frequencies above 16 mhz that could be reading seismo triggers.  Thanks for your time

Markww  in Houston Texas
N5UOA

Support your local disabled veterans units. From: Larry Cochrane Subject: Re: Manassas quake? Area history? Date: Sun, 05 Oct 1997 11:34:21 -0700 At 09:44 PM 10/3/97 -0400, Stephen Caruso wrote: I don't know about the history part, but, Bob Laney who lives in Herndon VA, about 15 to 25 miles from the event, received this event and it was his first one! He just got his system up and running when he capture the event. He sent in a very nice seismogram that can be download using the following URL: ftp:://psn.quake/net/quakes/9709/970929a.rl1. Bob Laney, can you send Dave Nelson your station info so he can add it to the PSN Map? Thanks, and good job getting your station up and running! -Larry Cochrane Redwood City, PSN >I was told there was an earthquake in VA recently. Did anybody see this >one? It was 2.5. Does Va get many ever? > >STEPHEN CARUSO CET >KB8UGH > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: PSN Italy works ! Date: Sun, 05 Oct 1997 11:50:08 -0700 Hi Guys, Great! Can you also send your event files to event@............. for archiving? This way we call can see them... I would also like to remind people that I have the new NewFile mailing list that will send you a email message when people send in event files to the event@... address above. This email message will not have the attached file like the NewEvent mailing list. You can use the web page at http://psn.quake.net/maillist.html to subscribe/unsubscribe to all of the lists I have. -Larry Cochrane Redwood City, PSN At 01:03 PM 10/5/97 +0200, you wrote: >Dear Larry C.,Edward C. and all PSN guys . > >PSN ITALY is now a reality ! Few days ago, as you know, in Central Italy >two earthquakes (5.5 and 5.9 followed by more than 90 aftershocks) have >caused 6 victims, about 120 injuried and more of 5000 homeless).The >famous S. Francesco Church in Assisi also has suffered very serious >damages ( a part of a Cimabue's masterpiece is forever lost ) . > >Francesco,Giovanni and I are keeping in touch H24 by phone and we >exchange our wq recordings daily for study proposals. > >This in the spirit of P.S.N. and the first really well-working >collaboration between amateurs in seismology in Italy during a seismic >period. > >Count on us ! > roberto > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: Cost for seismograph Date: Sun, 05 Oct 1997 12:18:29 -0700 At 07:04 AM 10/5/97 -0500, Mark wrote: > Anyone have the costs involved with doing a seismograph? That's a hard one... depends on what type of sensor you want to make (Lehman, SG, or something else), parts and equipment you have on hand, etc etc etc. Besides the sensor you will need some type of recording device. This could be a chart recorder (arrgggg) or a computer system with an Analog to Digital convert card and software. The homebuilt FAQ at http://psn.quake.net/info/homefaq.txt has more info about the hardware/software need to get a station up and running. >>> I see alot of portable units but something not pocket eating would be appreciated. I am a ham radio operator and im looking at frequencies above 16 mhz that could be reading seismo triggers. Thanks for your time Markww in Houston Texas <<<<<<<< Not sure what portable units you are talking about? As far as "looking for seismic triggers above 16 mhz", you on your own on that one... If you make a seismometer, you will be picking up seismic waves in the 30 second to 20hz range. Hope this helps. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: David A Nelson Subject: Re: Cost for seismograph Date: Mon, 06 Oct 1997 10:57:22 +1200 Larry, at least when my HDD died 3 days ago the good ol' pen recorder still chugged relentlessly on Dave Larry wrote: This could be a chart recorder (arrgggg) or a computer system with an Analog to Digital convert card and software. Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: PSN Italy works ! Date: Sun, 05 Oct 1997 23:10:10 -0600 Roberto- I am sorry to hear about the deaths, injuries and damage caused by the earthquake. I am glad to hear that your PSN connection has helped you, Giovanni, and Francesco to experience what has happened together ... and so you are closer to each other and to the earth of Italy. -Edward Dott. Roberto E. Pozzo wrote: > > Dear Larry C.,Edward C. and all PSN guys . > > PSN ITALY is now a reality ! Few days ago, as you know, in Central Italy > two earthquakes (5.5 and 5.9 followed by more than 90 aftershocks) have > caused 6 victims, about 120 injuried and more of 5000 homeless).The > famous S. Francesco Church in Assisi also has suffered very serious > damages ( a part of a Cimabue's masterpiece is forever lost ) . > > Francesco,Giovanni and I are keeping in touch H24 by phone and we > exchange our wq recordings daily for study proposals. > > This in the spirit of P.S.N. and the first really well-working > collaboration between amateurs in seismology in Italy during a seismic > period. > > Count on us ! > roberto > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: [Fwd: Manassas quake] Date: Sun, 05 Oct 1997 23:14:29 -0600 -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". From: Kees Verbeek Subject: Quake!!! Date: Tue, 7 Oct 1997 02:31:56 +0200 (MET DST) Hi all, Just had a quake , start , about 23.30 i'm afraid its Itali again?!!! Greetings , Kees Verbeek Holland. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Francesco" Subject: R: Quake!!! Date: Tue, 7 Oct 1997 02:40:42 +0100 Hello Kees, yes. Another medium quake, perhaps 5.5 Ms Have you registered the event? Please, get me file as soon as possible. I leave 40 km far the epicentre. Thank you Francesco Nucera ---------- > Da: Kees Verbeek > A: PSN-L Mailing List > Oggetto: Quake!!! > Data: marted=EC 7 ottobre 1997 1.31 > = > Hi all, > = > = > = > Just had a quake , start , about 23.30 i'm afraid its Itali again?!!! > = > Greetings , > = > = > Kees Verbeek > Holland. > = > = > _____________________________________________________________________ > = > Public Seismic Network Mailing List (PSN-L) > = > To leave this list email listserver@............. with the body of the = > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Dott. Roberto E. Pozzo" Subject: Re: Quake!!! Date: Tue, 07 Oct 1997 02:45:04 +0200 Kees Verbeek wrote: > > Hi all, > > Just had a quake , start , about 23.30 i'm afraid its Itali again?!!! > > Greetings , > > Kees Verbeek > Holland. > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L Yes, Kes it's a Central Italy quake . Again ! provisional calculations reports M +- 5.5 . Epicentral zone: near Assisi . Mercalli VII/VIII. No new victims reported (by now ) roberto _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Kees Verbeek Subject: Re: R: Quake!!! Date: Tue, 7 Oct 1997 03:41:49 +0200 (MET DST) At 02:40 7-10-97 +0100, you wrote: >Hello Kees, >yes. Another medium quake, perhaps 5.5 Ms >Have you registered the event? > >Please, get me file as soon as possible. > >I leave 40 km far the epicentre. > >Thank you > >Francesco Nucera > >---------- Hello Francesco, 40 km. !!!!!!!! I hope everything is alright over there. Sorry I can't give any computer-file about the quake because i'm a kind of old-fashion seismo-fanatic . I only record on a home-brewed drum recorder,that's behind me now , so I immediately can see when something goes wrong. Perhaps France can? again sorry for no help, greetings, Kees Verbeek Holland _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Needs for informations about a vertical sensor sismograph Date: Mon, 06 Oct 1997 18:02:01 -0700 Hi, I received this yesterday. Can anyone help them? They are not on the PSN-L list so please send email directly to them and CC the list. Thanks, -Larry Cochrane Redwood City, PSN >X-Authentication-Warning: www.utbm.fr: news set sender to using -f >Date: Sat, 05 Oct 1996 14:56:18 +0100 >From: Yohann LEDIEU >X-Mailer: Mozilla 3.01 (WinNT; I) >To: cochrane@.............. >CC: nicolas-rivron@....... >Subject: Needs for informations about a vertical sensor sismograph >X-MIME-Autoconverted: from 8bit to quoted-printable by www.utbm.fr id OAA02937 > >Dear sir >We are two french students from the Institut polytechnique de Sevenans >(IPSé). >As a project, this year, we have to build a vertical sensor sismograph >so that we need some more informations about it. >We already read your web site but we didn't found anything about >vertical sensor. >Could you please help us by sending us informations, plans or web >addresses. > yours faithfully, > > Rivron Nicolas > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: [Fwd: USGS Menlo Park move] Date: Mon, 06 Oct 1997 23:26:12 -0600 -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". From: Edward Cranswick Subject: Re: USGS Menlo Park move Date: Mon, 06 Oct 1997 23:37:46 -0600 Ted Blank- But the reality of the situation is that you now, and the original PSN members then, and the USGS Menlo Park all live where the earthquakes are .... but I just live in Colorado and talk about it. So ultimately it's up to all you Bay Area people to be aware of and prepare yourself for the earthquakes that are part of what makes the Bay Area such a beautiful place to live. However, thank you for letting me know what's happening. -Edward -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: shammon1@............. Subject: Re: Needs for informations about a vertical sensor sismograph Date: Mon, 06 Oct 1997 23:40:25 -0700 Larry Cochrane wrote: >=20 > Hi, >=20 > I received this yesterday. Can anyone help them? They are not on the PS= N-L > list so please send email directly to them and CC the list. >=20 > Thanks, >=20 > -Larry Cochrane > Redwood City, PSN >=20 > >X-Authentication-Warning: www.utbm.fr: news set sender to > using -f > >Date: Sat, 05 Oct 1996 14:56:18 +0100 > >From: Yohann LEDIEU > >X-Mailer: Mozilla 3.01 (WinNT; I) > >To: cochrane@.............. > >CC: nicolas-rivron@............. I sent them the Vertical.GIF and AMP_= 2.GIF files file from the San Jose BBS. Regards, Steve Hammond PSN - San Jose, California=20 > >Subject: Needs for informations about a vertical sensor sismograph > >X-MIME-Autoconverted: from 8bit to quoted-printable by www.utbm.fr id > OAA02937 > > > >Dear sir > >We are two french students from the Institut polytechnique de Sevenans > >(IPS=E9). > >As a project, this year, we have to build a vertical sensor sismograph > >so that we need some more informations about it. > >We already read your web site but we didn't found anything about > >vertical sensor. > >Could you please help us by sending us informations, plans or web > >addresses. > > yours faithfully, > > > > > > >=20 > _____________________________________________________________________ >=20 > Public Seismic Network Mailing List (PSN-L) >=20 > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: shammon1@............. Subject: Re: Needs for informations about a vertical sensor sismograph Date: Mon, 06 Oct 1997 23:57:11 -0700 Larry, I sent the two students the Vertical.GIF file and AMP_2.GIF file from the PSN San Jose BBS.=20 Regards, Steve Hammond PSN San Jose, California Larry Cochrane wrote: >=20 > Hi, >=20 > I received this yesterday. Can anyone help them? They are not on the PS= N-L > list so please send email directly to them and CC the list. >=20 > Thanks, >=20 > -Larry Cochrane > Redwood City, PSN >=20 > >X-Authentication-Warning: www.utbm.fr: news set sender to > using -f > >Date: Sat, 05 Oct 1996 14:56:18 +0100 > >From: Yohann LEDIEU > >X-Mailer: Mozilla 3.01 (WinNT; I) > >To: cochrane@.............. > >CC: nicolas-rivron@....... > >Subject: Needs for informations about a vertical sensor sismograph > >X-MIME-Autoconverted: from 8bit to quoted-printable by www.utbm.fr id > OAA02937 > > > >Dear sir > >We are two french students from the Institut polytechnique de Sevenans > >(IPS=E9). > >As a project, this year, we have to build a vertical sensor sismograph > >so that we need some more informations about it. > >We already read your web site but we didn't found anything about > >vertical sensor. > >Could you please help us by sending us informations, plans or web > >addresses. > > yours faithfully, > > > > > > >=20 > _____________________________________________________________________ >=20 > Public Seismic Network Mailing List (PSN-L) >=20 > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: David A Nelson Subject: lighter side of software Date: Wed, 08 Oct 1997 12:58:55 +1200 hi all, here's a little gem I discovered that I hope will bring a smile to the faces of the masses DEFINITION OF WINDOWS 95: 32-bit extensions and a graphical shell for a 16-bit patch to an 8-bit operating system originally coded for a 4-bit microprocessor, written by a 2-bit company that can't stand 1-bit of competition. Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: lighter side of software Date: Wed, 08 Oct 1997 11:41:09 -0700 Very good... and unfortunately true! -Larry At 12:58 PM 10/8/97 +1200, you wrote: >hi all, > here's a little gem I discovered that I hope will bring a smile to >the faces of the masses > > DEFINITION OF WINDOWS 95: > > 32-bit extensions and a graphical shell for a > 16-bit patch to an > 8-bit operating system originally coded for a > 4-bit microprocessor, written by a > 2-bit company that can't stand > 1-bit of competition. > > >Dave _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: lighter side of software Date: Wed, 08 Oct 1997 14:19:49 -0600 Dave & Larry- But that proves the system and the people who use it are very adaptable unlike some other systems which required an investment of a 100k just to logon on -- and that is the sign of a organism/system that survives by evolving. -Edward Larry Cochrane wrote: > > Very good... and unfortunately true! > -Larry > > At 12:58 PM 10/8/97 +1200, you wrote: > >hi all, > > here's a little gem I discovered that I hope will bring a smile to > >the faces of the masses > > > > DEFINITION OF WINDOWS 95: > > > > 32-bit extensions and a graphical shell for a > > 16-bit patch to an > > 8-bit operating system originally coded for a > > 4-bit microprocessor, written by a > > 2-bit company that can't stand > > 1-bit of competition. > > > > > >Dave > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: compare. of 3 sensors for Kermadec Date: Wed, 8 Oct 1997 20:28:12 -0400 Larry, I downloaded 970920A.BKN, .LC1 & .LC3. of the Kermadec 6.9 event. = Thanks for taking the trouble of making files so that it is easy to compa= re them. The comparison is very informative. (My great bad luck was to have= my rig down for this event--we had a power dip while I was out of town an= d I had not provided for auto restart of SDR in AUTOEXEC.BAT.) sensor p-p surf p-p bg = S N = S/N .BKN Berk. broadband 5340 200 27 .LC1 Lehman 3440 170 20 .LC3 S-G new integ. 9740 800 12 Since the p-p bg is an eyeball est., I'm not sure that the difference between 27 and 20 is significant. Since the S/N ratio would be dependent= on the high freq. cutoff, I looked at the FFT for all three and it looks like they are all the same. The visual appearance of all three 'grams is remarkably similar. Lay = & Wallace ("Modern Global Seismology") p 188 show that the broadband sensor= s have response from ~ 9 Hz to less than .001 Hz. I was amazed that the FFT's for the three sensors were remarkably similar and esp. that they showed about the same fraction of energy at low freqs., say below .02 Hz.= Since I have only a Lehman, I was delighted to see that yours was only slightly inferior to the broadband rig. I suppose that the Berk. sensor = is in a good location (borehole?) so the similarity of the S/N must make you= feel good about your location. I have some questions:1. Since the S wave is very strong, how come the = SS and SSS seem to be absent? 2. The LQ calculates to be at about 16:56:12= =2E = What is the nice 'blob' (do you have a better term for this?) centered a= t about 16:51:48? This 'blob' has a period of about 23" and the sections around the LQ and LR are about 16". I would greatly appreciate your repeating this exercise the next time w= e have a teleseismic boomer--one which I should also get. A suggestion for a new feature for WINQUAKE--how about a facility for getting an RMS avg. value for a zoomed region? This would be a better meas. of the background amplitude. Maybe you can think of something bett= er than RMS. Bob Barns = = = = _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Kasey Benson" Subject: Re: Wow, what was that Date: Wed, 8 Oct 1997 20:03:14 -0700 ---------- > How does one get off this list. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Date: Thu, 9 Oct 1997 02:24:49 -0700 (PDT) Subject: Parkfield Prediction X-Mailer: Hi all! I remember reading about the possibility of an 8.0 occurring on the San Andreas fault immediately following a 6.0 or greater in the Parkfield area. Can anyone enlighten me about this theory? Also, seeing very erratic low frequency 0-3 Hz geo-magnetic field disturbances in the Cucamonga/San Bernardino County area on my equipment. Can anyone else correlate with me on this? I think it might be something else going on on the San Jacinto fault that is causing it. reply to: frankcnd@.......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Paul Subject: Re: lighter side of software Date: Thu, 09 Oct 1997 02:36:20 -0700 David A Nelson wrote: > hi all, > here's a little gem I discovered that I hope will bring a smile to > the faces of the masses > > DEFINITION OF WINDOWS 95: > > 32-bit extensions and a graphical shell for a > 16-bit patch to an > 8-bit operating system originally coded for a > 4-bit microprocessor, written by a > 2-bit company that can't stand > 1-bit of competition. > > Dave > > Co-ordinator: > New Zealand > Public Seismic Network > Dave A. Nelson ZL4TBN > 24 Jensen St., > Green Is., Dunedin, > South Is.. New Zealand. > > http://psn.quake.net/dave/home.htm > > IF there indeed are other parallel universes... I can now rest in the > knowledge, that in at least one of them, I am filthy rich and drive a red > Ferrari > > ____________________________________________________________________ That one kept me laughing for hours, Dave! Thanks for passing it along. -- Stephen :^) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: GeoMonitr@....... Subject: Re: HAM interested in earthquake prediction Date: Thu, 9 Oct 1997 12:25:12 -0400 (EDT) Many people have been trying to duplicate the experiments of Anthony Fraser-Smith at Stanford, by detecting ULF signals that may be a link between earthquake precursors and human reactions. I started a newsletter on the subject, GeoMonitor, and I have all 6 years of back issues, including some amateur circuits for ULF detection. The newsletter is now being published by Charles Patton, 21490 Camino Arriba, Murrieta, CA 92562; (909) 698-9657. Good luck VInce _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: GeoMonitr@....... Subject: Re: HAM interested in earthquake prediction Date: Thu, 9 Oct 1997 12:28:09 -0400 (EDT) Yeah, as if quake predictors are right up there with Astrologers! Geez, when are you so-called scientists going to get an OPEN MIND!!?? Is it so inconceivable that precursors would have an electromagnetic component that a human or animal is capable of picking up? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: GeE777@....... Subject: Re: HAM interested in earthquake prediction Date: Thu, 9 Oct 1997 14:17:51 -0400 (EDT) Hi Why don't we check it out. Have dog pounds keep track of how many dogs are lost and/or picked up each day. See if this number increases prior to an earthquake. That certainly can't be a very expensive experiment. n a message dated 97-10-09 12:31:02 EDT, GeoMonitr@....... writes: << Is it so inconceivable that precursors would have an electromagnetic component that a human or animal is capable of picking up? >> _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Rev. Bob Shannon" Subject: Re: HAM interested in earthquake prediction Date: Thu, 9 Oct 1997 13:51:29 -0700 (PDT) On Thu, 9 Oct 1997 GeoMonitr@....... wrote: > Is it so inconceivable that precursors would have an > electromagnetic component that a human or animal > is capable of picking up? When I was in my single digits back in the early 1950's I truly enjoyed building electronic projects...I felt that I could design some myself and it was the phase of life that led me to working in electronics for many years. Building and monitoring earthquake devices sounds like fun...and refining the instruments sounds like a bit of fun but maybe a bit more like drudgery.....On the other hand...attempting to figure out what sort of possible precursors could be causing 'signals' which humans could possibly be capable of receiving is even more exciting.... Let me example. I feel that ELF has a finger in this somewhere and so does Ben Parks of Placerville Ca. Ben has been following F-Smiths work and is a friend of his. Ben designed some pretty hefty A-D hard and software to monitor ULF and ELF. I have a ref. to him on my homepage.... I am wondering a bit with Vince, if it is at least in the same ballpark to monitor precursors as well as the actual quake...or at least make an attempt to discover the thread which ties them? Bob http://iea.com/~rshannon Rev. Robert Shannon Sr. Hon. DD Theology Pinpoint Newsletter "The web existed before spiders. The web existed before the net... We are all a part of the web and whatever we do to part - we do to the whole" ------------------------------------------------------------------ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Caruso Subject: Re: HAM interested in earthquake prediction Date: Thu, 9 Oct 1997 20:42:10 -0400 (EDT) I remember being in NW Wash. state in the mid 70's. I was on the road and settled down for the night. I remember hearing the animals around the area sounding distressed and then, boom, there was a tremor. The next night Iwas in someones house on the third floor and there was another yet stronger. On Thu, 9 Oct 1997 GeE777@....... wrote: > Hi > Why don't we check it out. Have dog pounds keep track of how many dogs are > lost and/or picked up each day. See if this number increases prior to an > earthquake. That certainly can't be a very expensive experiment. > > > > > n a message dated 97-10-09 12:31:02 EDT, GeoMonitr@....... writes: > > << > Is it so inconceivable that precursors would have an > electromagnetic component that a human or animal > is capable of picking up? > > >> > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L STEPHEN CARUSO CET KB8UGH _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: HAM interested in earthquake prediction Date: Thu, 09 Oct 1997 20:24:08 -0500 Stephen Caruso wrote: > > I remember being in NW Wash. state in the mid 70's. I was on the road and > settled down for the night. I remember hearing the animals around the area > sounding distressed and then, boom, there was a tremor. The next night > Iwas in someones house on the third floor and there was another yet stronger. > > Hear is my story. :) I was in Iran in the 1960's when one of the big quakes struck. I distinctly remember the day before the quake I had a conversation with my dad about what to do if a quake happened. Chance or some sense -- I have no idea. Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: David A Nelson Subject: Mt Ruapehu "burps" Date: Fri, 10 Oct 1997 17:33:36 +1200 Hi all, Seismic activity has again started to rise below the crater lake of Mt Ruapehu (central Nth Is., New Zealand) after a 15 months of calm since the last large eruptions. Almost continuous harmonic tremor as well as individual events are 3 times up on the normal level of activity. And early am on the 10 Oct 97 NZST (late pm UTC 9 Oct.) the first small steam cloud was seen above the mountain. The Alert has been raised to level 2 on the international scale of 1 to 5, 5 being full maj. eruption Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: TMichel917@....... Subject: Streckeisen Date: Fri, 10 Oct 1997 15:08:38 -0400 (EDT) Hi Jean-Yves! Some time ago I read your mail concerning the Streckeisen seismometers. The Streckeisen STS-1 force-balance-seismometer is in its current version a "very-broad-band"-seismometer with a response flat to velocity from 0.1 to 360 sec period. It is only for observatory use. The mechanical design of the vertical sensor (STS-1V/VBB) is based on a semicircularly bent leaf spring which produces a very small and linear restoring force. The horizontal sensors (STS-1H/VBB) use pendulums of the "garden-gate"-type. The mechanics are shielded against variations in temperature, air pressure and magnetic field (only STS-1V/VBB). The external electronics use a combination of differential, proportional and integral feedback. The boom position is sensed by a LVDT (linear variable differential transformer) and the feedback force is generated by moving-coil transducers. The mechanics of the STS-2, which is also a force-balance-seismometer, are different from that of the STS-1 while the electronics are very similar. The STS-2 consists of three identical obliquely-oriented sensors in a single, sealed package. It is optimized for quick and simple installation. As boom position sensor the STS-2 uses a capacitive displacement sensor, the feedback force is generated by a moving coil transducer. Technical Data STS-1 Mechanical free period: Virtually infinite Response: Flat to ground velocity at a responsitivity of 2 x 1200 V sec/m Long period corner: 20 or 360 sec second order cutoff with 0.707 critical damping Short period corner: 0.1 sec Clip level: +/- 8 mm/s ground motion (0.1 - 360 sec) Dynamic Range: > 140 dB Prices: STS-1V/VBB appr. 17.000 SFr STS-1H/VBB appr. 12.500 SFr Technical Data STS-2 Mechanical free period: Virtually infinite Response: Flat to ground velocity with a responsitivity of 2 x 750 V sec/m Long period corner: 120 sec Short period corner: > 50 Hz Clip level: +/- 13 mm/s ground velocity Dynamic Range: > 140 dB Price: STS-2 appr. 19.000 SFr If you have any questions or need more information please feel free to contact me. Torsten _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: compare. of 3 sensors for Kermadec Date: Fri, 10 Oct 1997 15:04:19 -0700 At 08:28 PM 10/8/97 -0400, Bob Barns wrote: >Larry, > I downloaded 970920A.BKN, .LC1 & .LC3. of the Kermadec 6.9 event. >Thanks for taking the trouble of making files so that it is easy to compare >them. The comparison is very informative. (My great bad luck was to have >my rig down for this event--we had a power dip while I was out of town and >I had not provided for auto restart of SDR in AUTOEXEC.BAT.) [snip] > Since I have only a Lehman, I was delighted to see that yours was only >slightly inferior to the broadband rig. I suppose that the Berk. sensor is >in a good location (borehole?) so the similarity of the S/N must make you >feel good about your location. Information about the Berkeley sensor can be found at: http://www.seismo.berkeley.edu/seismo/bdsn/station_book/bks.html Its located in a vault, somewhere near the campus. My location is another story, and proves that you can record EQs in the city. I live a few hundred yards away from a major freeway (US 101) and to add insult to injury there is an industrial highway between my house and the freeway. On the other side of the house, about 1 1/2 mile away, are railroad tracks. For the last few months there has been some major construction work going on right down the street from me. For those of you who know the area they are demolishing the old Circle Star theater and building some office towers on the lot. When they where demolishing the theater my sensors where getting too 1/2 (~15k counts) the max counts of my 16 bit A/D converter. Now that the theater is gone, the noise during the day has reduced a little. I can see on my SDR system exactly when they stop for lunch etc. I can't wait from them to start there pile driving... They did a test one a few weeks ago and it sure drove my sensor, and my nerves (I work at home, so I'm around here when they do the work), crazy. > I have some questions:1. Since the S wave is very strong, how come the SS >and SSS seem to be absent? 2. The LQ calculates to be at about 16:56:12. >What is the nice 'blob' (do you have a better term for this?) centered at >about 16:51:48? This 'blob' has a period of about 23" and the sections >around the LQ and LR are about 16". I have a hard time seen any of the other phase myself. Not sure why... > I would greatly appreciate your repeating this exercise the next time we >have a teleseismic boomer--one which I should also get. Will do. > A suggestion for a new feature for WINQUAKE--how about a facility for >getting an RMS avg. value for a zoomed region? This would be a better >meas. of the background amplitude. Maybe you can think of something better >than RMS. I'll look into it. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: David A Nelson Subject: Ruapehu Date: Sat, 11 Oct 1997 18:07:37 +1200 Hi all, The mountain continues to increase in activity, Today (Sat 11 Oct97 NZ) the weather cloud cleared to show large billowing plumes of toxic gas clouds rising several thousand metres above the mountain. The rumbles/booms from the crater can be heard for several kilometres and at least one skifield is closing for safety. the others will prob. follow soon. The Alert level remains at "2" Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Three Dimensional Seismograph, thoughts, and a poem! Date: Sun, 12 Oct 1997 10:15:53 +0100 Hello everyone, from the other side of the 'BIG POND'! I have just joined PSN and have started reading the archives.... WOW, it takes some time, doesn't it? As we don't suffer any large events here in England, I am using single pivot points for hor. pendulums...... Pivots are 1930's gramophone needles (which have SMOOTH, hard ground ..005 " radiused tips), sitting into hardened domed anvils, on the horizontal pendulums. (Two-90 degree opposed, for NS and EW orientation). Attempting to get swing periodicity of 60 SECONDS..... somewhat difficult to obtain with beam lengths of only 24 inches. (The vertical offset required calculates out to only .01 inches!) .015 piano wire suspension. >>>> HAS ANYBODY TRIED USING CARBON FIBRE FOR SUSPENSION? WOULD IT STRETCH? <<<<<< With a vertical seismo in-tow with the 2 horizontals, I hope to have a Three-Dimensional seismograph. Software will show SECTIONS both through earth NS and EW, and also PLAN of earth movements, in addition to normal o/p traces on VDU etc. All Hall-Effect sensing + 12 bit A/D. RE YOUR PREVIOUS CHATS ON SEISMO ADJUSTMENTS, to keep pivot points aligned EXACTLY vertically below suspension as viewed from front..... I got hold of some .75" dia ball races with a small slot ground in the o/d. These are clamped in a 3/8 bolt. (with 2 nuts each side of race) The ball race 'bolt' is horizontally mounted at top of upright, (where the piano wire is normally anchored) into a 3/8 tapped hole, and the piano suspension goes OVER the race, IN THE SLOT, and is anchored lower down, (using yet another bolt and a thrust race for up/down adjustment to wire/beam). All this gives fine ALL ROUND adjustments to beams. The bolt thread mustn't be course for smooth adjustment...(> 30 TPI). Planning to use 20x50ohm resistors in series on 240v mains, to GENTLY heat seismo enclosure....each R giving off 3watts, keeps to 75 degreeF in winter. Does anyone have any criticism/comment on this type of heating, please???? Someone mentioned last March that heat should be positioned at TOP of enclosures. ANY comment on anything above would be appreciated. I shall study your archives further. It's all very interesting. But for now, as many of you folk seem to be interested in astronomy as well as seismology, you may like to read my own SHORT, philosophical poem about these fields....... W H E N. When the earth trembles I shall be aware. When a star twinkles I shall sit and stare. When oblivion takes me I shall not care........ For in Earth AND in Heaven, I have been there. Prewar Albert Noble. Regards to all, 'over there'. (and ANYWHERE else!) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: steve jones Subject: Address for Oregon Scientific? Date: Sat, 11 Oct 1997 09:21:44 -0700 Does anyone have a telephone number / email address / etc. to reach Oregon Scientific? Thanks in advance! Steve Jones _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: bfryer@............ (Bob Fryer) Subject: Re: Address for Oregon Scientific? Date: Sat, 11 Oct 1997 07:53:08 -0700 (PDT) Hi Steve, Address: 18383 SW Boones Ferry Rd. Tigard, OR 97224 (503) 639-8883 Bob -- Beaverton, OR -- on the Cascadia Subduction Zone >Does anyone have a telephone number / email address / etc. to reach >Oregon Scientific? Thanks in advance! > >Steve Jones ----- earthquake WARNING research ----- --- animals, people, scientific evidence --- --- http://www.teleport.com/~bfryer --- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert Avakian Subject: Re: HAM interested in earthquake prediction Date: Sat, 11 Oct 1997 19:52:17 -0700 Someone help me on this, but I am sure I reember the Chineeses having at least one success warning of a major quake by monitoring the behavior of flocks of ducks in the area's villages. Was this success ever reperted? Or was it serendipity? Alsso, i remeber seeing a piece on TV about the guy in LA who predicts quakes by, among other things, the number of lost pet ads in the papers. Bob GeoMonitr@....... wrote: > > Many people have been trying to duplicate the experiments > of Anthony Fraser-Smith at Stanford, by detecting > ULF signals that may be a link between earthquake > precursors and human reactions. > > I started a newsletter on the subject, GeoMonitor, > and I have all 6 years of back issues, including some > amateur circuits for ULF detection. The newsletter is now > being published by Charles Patton, 21490 Camino Arriba, > Murrieta, CA 92562; (909) 698-9657. > Good luck > VInce > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Erich F. Kern" Subject: Drum Recorders Date: Sat, 11 Oct 1997 20:28:26 -0700 Hi All, Does anyone have a drum recorder they'd like to sell? Am willing to refurbish to some extent, but it must have the pen driver and major components. Will pick up in So. California. Please respond to my e-mail address and NOT to this list. Regards, Erich Kern ekern@......... *************************************************************** Please visit our web site at: http://www.dconn.com/FatQuartersSoftware Thank you ************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: David A Nelson Subject: Ruapehu update Date: Sun, 12 Oct 1997 17:13:23 +1200 Ruapehu today (Sun 12 Oct. NZ) did a throat clearing with its first ash eruption in this current burst of activity. The action was captured on video tape by TV news cameramen who were near the summit at the time. The Alert Level remains at 2 Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: HAM interested in earthquake prediction Date: Sun, 12 Oct 1997 09:21:07 +0100 Hi, See Bruce Bolts book, 'Earthquakes and Geological Discovery'. Pub1993 by Scientific American Library. Chapter 8...'Forcasting Earthquakes'. (geologist in San Franscisco bay area, DID predict using lost animals!!) ....See page 182. Hope this helps. Regards, Albert Noble, (England). Robert Avakian wrote: > Someone help me on this, but I am sure I reember the Chineeses having at > least one success warning of a major quake by monitoring the behavior of > flocks of ducks in the area's villages. Was this success ever > reperted? Or was it serendipity? > > Alsso, i remeber seeing a piece on TV about the guy in LA who predicts > quakes by, among other things, the number of lost pet ads in the papers. > > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: Three Dimensional Seismograph, thoughts, and a poem! Date: Sun, 12 Oct 1997 08:34:20 -0700 Greetings Prewar -- Glad to have you in the group. I'll try to comment/answer a couple of things you mentioned... >to keep pivot points >aligned EXACTLY vertically below suspension as viewed from front..... I do this by getting it close mechanically, then changing the level of the entire instrument for the final adjustment. Do you think there is a difference in performance using one technique vs. the other? >Planning to use 20x50ohm resistors in series on 240v mains, to GENTLY >heat seismo enclosure....each R giving off 3watts, keeps to 75 degreeF >in winter. Does anyone have any criticism/comment on this type of >heating, please???? Someone mentioned last March that heat should be >positioned at TOP of enclosures. ANY comment on anything above would >be appreciated. Am I understanding you correctly that you will have 60 watts total? I use 2 watts total for the heater, mounted at the top, and my enclosure is insulated on all sides except the bottom by about 2" of urethane foam. I believe the idea is to stratify the air inside the enclosure in order to reduce convection currents as much as possible. I have all the electronics located outside the enclosure to avoid convection from that. With the heater mounted at the top, the air should be the warmest at the top and coolest at the bottom, forming a smooth gradient in between. This gradient is hopefully due to mostly conduction and minimally convection. I haven't tried it, but I suppose it would be helpful to shield the heater in such a way as to minimize radiation to components below it. Hope this helps. Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Clark Wockner Subject: detect ble distance Date: Sun, 12 Oct 1997 13:06:11 -0700 Hi all: I seem to be missing most of the quakes others are getting. Is it because most seismic zones are so far from Illinois or is it because of some other reason? I did not record the Kermadek 6.9 a while back and I was sure I should have gotten it. What kind of distance are the rest of you getting with your Lehmans? Comments please. Thanks all Clark _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: detect ble distance Date: Sun, 12 Oct 1997 00:08:33 -0700 Hi Clark I live on the west coast. I can pick up 6.5 events @ 9000k most of the time. I would guess you're another 3000k to the east. It depends on how high you can get away with setting your gain and howfar you are away from the epicenter. I think where your sensor is located locally could have an effect on recording but I don't think that should affect the large teleseismic events. Most event files I've seem are < 11,000k away. I guess you will have to do the math from your location. It seems maybe you would have better luck picking up events from the east ,eg Italy,middle east etc. There are "dead" zones which others have mentioned and could probably explain there angle range better than I. I miss events because I run on a trigger system. Others use continuous recording. Which do you have? I hope that helps a little. Barry >Clark Wockner wrote: > > Hi all: > I seem to be missing most of the quakes others are getting. Is it > because most seismic zones are so far from Illinois or is it because of > some other reason? I did not record the Kermadek 6.9 a while back and I > was sure I should have gotten it. What kind of distance are the rest of > you getting with your Lehmans? Comments please. > Thanks all > Clark > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: Three Dimensional Seismograph, thoughts, and a poem! Date: Sun, 12 Oct 1997 14:50:25 -0500 prewar wrote: > With a vertical seismo in-tow with the 2 horizontals, I hope to > have a Three-Dimensional seismograph. Software will show SECTIONS both > through earth NS and EW, and also PLAN of earth movements, in addition > to normal o/p traces on VDU etc. All Hall-Effect sensing + 12 bit A/D. > I would be very interested in hearing more about how you plan on viewing the 3d data. I am working on a 3 axis instrument with each axis having identical response. But I haven't any good ideas on viewing the data. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: TESMECO@....... Subject: Re: Ruapehu update Date: Sun, 12 Oct 1997 18:54:25 -0400 (EDT) thanks to you i am getting interested in this one i like the daily up dates thanks _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: electronic oscillator Date: Sun, 12 Oct 1997 09:47:43 -0700 Hi All I have one for you . Bare with me. I would like to increase the period of a Lehman . I made a phase shift oscillator to represent an electronic pendulum. With a gain below unity, I got damping. The period of the oscillator was determined by the resistors and capacitors used. I put an external input to oscillator by attaching a coil of magnet wire. By bringing a magnet near the coil I could get the oscillator to oscillate and damp out just like an excited pendulum. I would like to replace the coil with a displacement device like an LVDT. I would then mount the LVDT on the end of a "garden gate". I would then set the natural frequency to as low as I like, electronically. The output of the oscillator would be feed back to the garden gate by a second coil, thus making the garden gate respond like the electronic oscillator. The LVDT could be measured or a third coil could be used to represent the Lehman's velocity sensor. Sound pretty Rube Golberg, but would it work? Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Ruapehu update Date: Mon, 13 Oct 1997 17:27:28 +1200 Hi ??, I don't know your name as you didn't sign your mail, there are a lot of us who are whish that this mountain would do a proper throat clear and really blow its top.... the last really major eruption ( say on the scale of Mt. St.Helens) from a New Zealand volcano was in 1886 when Mt. Tarawera, ~100km nth of Ruapehu, let rip causing deaths and much damage to the Native Maori and early European settlements in the region at that time. As far as I am aware it is the only eruption to cause direct loss of life in modern times. A non-eruption related lahar from Mt. Ruapehu, christmas, 1953 wiped out a railway bridge causing the passenger train to plunge to destruction with the loss of 151 lives. this was caused by ash from a small eruption, several years earlier, blocking the outlet from the crater lake and as the lake level rose the ash dam finally burst sending a huge lahar down the river. Dave At 06:54 PM 10/12/97 -0400, you wrote: >thanks to you i am getting interested in this one i like the daily up dates >thanks > Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Heating enclosures and multi-seismos. Date: Mon, 13 Oct 1997 12:42:01 +0100 Hi Karl, Many thanks for reply.....my FIRST contact outside England.....been on internet only 3 weeks, so please excuse if protocol isn't quite correct. I have to use my idea, re ball races adjust. as I have BOTH hor. Pendulums on same frame...using normal method would put one out of line, when adjusting the other, and so on. In fact, the VERTICAL seismo is also on same frame... perhaps I have troubles to come!! It was common practice many years ago to have multi-seismo mountings, so for convenience sake, I have done this. Hasten to add that frame upright is 1"x1" steel, AND braced, so its anti-flexing! Yes, 60W is correct...I have a heated insulated hut, and inside it, is a further insulated enclosure which houses 3 seismos....60W required in winter to keep this enclosure to 75F, thermostatically controlled. I assume that your own enclosure is small, or ELSE your winters are very mild, as you only need 2W. Rather nice to be so low. Noted that your heat is from TOP. I was going to put my R's all around BOTTOM perimeter, but perhaps not, after your comment. Yes, would have thought any DIRECT heat onto seismos is to be avoided at all costs. I couldn't really believe, sitting in my little hut, in the middle of England, in a tiny village, that someone half way around the world would reply. Am finding the archives a great source of info and experience... ....still reading through them ALL! (shall never have time now to get my 3 seismo monsters working!) Many thanks again for comments/advice, Regards. Albert Noble. Karl Cunningham wrote: > Greetings Prewar -- > > Glad to have you in the group. I'll try to comment/answer a couple of > things you mentioned... > > >to keep pivot points > >aligned EXACTLY vertically below suspension as viewed from front..... > > I do this by getting it close mechanically, then changing the level of the > entire instrument for the final adjustment. Do you think there is a > difference in performance using one technique vs. the other? > > >Planning to use 20x50ohm resistors in series on 240v mains, to GENTLY > >heat seismo enclosure....each R giving off 3watts, keeps to 75 degreeF > >in winter. Does anyone have any criticism/comment on this type of > >heating, please???? Someone mentioned last March that heat should be > >positioned at TOP of enclosures. ANY comment on anything above would > >be appreciated. > > Am I understanding you correctly that you will have 60 watts total? > > I use 2 watts total for the heater, mounted at the top, and my enclosure is > insulated on all sides except the bottom by about 2" of urethane foam. I > believe the idea is to stratify the air inside the enclosure in order to > reduce convection currents as much as possible. I have all the electronics > located outside the enclosure to avoid convection from that. With the > heater mounted at the top, the air should be the warmest at the top and > coolest at the bottom, forming a smooth gradient in between. This gradient > is hopefully due to mostly conduction and minimally convection. I haven't > tried it, but I suppose it would be helpful to shield the heater in such a > way as to minimize radiation to components below it. > > Hope this helps. > > Karl Cunningham > La Mesa, CA. > PSN Station #40 > karlc@....... > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Heating enclosures and multi-seismos. Date: Mon, 13 Oct 1997 23:56:40 +1200 Albert Did you think about just using a 60W lightbulb, If your enclosure is metal you could put a perspex window in it and the light would let you keep an eye on the inside without having to remove the cover. Dave _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: electronic oscillator Date: Mon, 13 Oct 1997 07:25:55 -0500 I have been thinking about a similar concept for some time. Here are some additional thoughts. What determines the mechanical period of the pendulum is the rate at which the "restoring" force increases with displacment from rest. If one were to adjust the pivot alignment so that there was no mechanical restoring force then one could replace the mechanical force with a magnet and coil being fed from the LVDT output. By adjusting the gain of this circuit one could in theory set the period to any value desired. A big problem that I see with this is that the mechanical adjustments are very minute and subject to all sorts of outside infuuences. Unless the electronics can somehow compensate for these infulences things won;t work too well. Jim Hannon gbl@....... on 10/12/97 11:47:43 AM Please respond to psn-l@............. To: psn-l@............. cc: (bcc: James M Hannon/CedarRapids/Collins/Rockwell) Subject: electronic oscillator Hi All I have one for you . Bare with me. I would like to increase the period of a Lehman . I made a phase shift oscillator to represent an electronic pendulum. With a gain below unity, I got damping. The period of the oscillator was determined by the resistors and capacitors used. I put an external input to oscillator by attaching a coil of magnet wire. By bringing a magnet near the coil I could get the oscillator to oscillate and damp out just like an excited pendulum. I would like to replace the coil with a displacement device like an LVDT. I would then mount the LVDT on the end of a "garden gate". I would then set the natural frequency to as low as I like, electronically. The output of the oscillator would be feed back to the garden gate by a second coil, thus making the garden gate respond like the electronic oscillator. The LVDT could be measured or a third coil could be used to represent the Lehman's velocity sensor. Sound pretty Rube Golberg, but would it work? Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: THREE DIMENSIONAL Seismograghs and software. Date: Mon, 13 Oct 1997 13:32:50 +0100 Hi Jim, T H R E E D I M E N S I O N S. I was very interested to hear that you too are building a three axis seismo 'cluster'. I do not know what sort of software you run...is it home brew, or off the shelf? What language are you running I wonder. I have to confess that I only use a 'souped up' version of BBC BASIC....B U T, it has a smashing built in assembly language facility, which can be used for any nitty gritty fast programing. In addition to all the normal seismo programming on my PC, keyboard selection to show any of the following... 1......All 3 traces from o/p of NORTH/SOUTH, EAST/WEST and VERTICAL seismos shown TOGETHER, (each one in a different colour.) 2......Above, but seperate. 3......A large full screen draw of a PLAN VIEW of earth. The NS seismo o/p controlling the vertical component of the trace, and the EW seismo controlling the horizontal. 4.......As 3 but section through earth parallel with equator. EW seosmo o/p controls horizontal draw and VERTICAL seismo, the vertical of course. 5.......As 4 but section through earth from pole to pole. This time EW seismo o/p controls horizontal and as above, and the vertical seismo, the vertical. 6........3,4 and 5 above on screen together ,(but smaller plots of course). 7........2,3,4 and 5 all on screen together, (with even smaller plots.). 8........Have an automatic rain gauge installled ( tipping bucket design). PC sums rainfull each day and shunts it to HD....Screen can also show bar graph of rain on daily/month/yearly basis. (my PC won't yet do the washing up ..... .....but I'm working on it!!) As my seismos are not yet working, I have carried out SIMULATION on my PC program, using randomly generated values for 3 seismos and all seems OK. One thing I found was that unlike the normal o/p trace, when showing 3 to 6 above, and when there is little activity. As one is constantly drawing and redrawing a trace over the same area, then confusion begins to reign on the screen. I found that this can be partly overcome by changing the colour of the draw each time the o/p from the 3 seismos is read. (in my case 50 times per sec). This gives a multi-coloured plotting which is better than using just white on a black backgnd. (Colours are randomly selected by the PC, each conversion). Also one could automatically increase the SIZE of drawings, during quiet periods......... The o/p from seismos (if 12 bit), must be divided down to fit in with the number of pixels on the screen mode used.....12bit gives over 4096 posible positions, and it is unlikely that 4096 pixels are available on PC, X or Y axis.. For example, I have +10v, 12 bit A/D converter, sampling each seismo in turn. So 5v pos o/p gives me values up to 2048. For development work I use 640x480 screen mode......so 2048 must be divided by 4 = 512. Each increment step in A/D conversion is now represented by 1 pixel with some screen area to spare. eg. 1000 o/p divided down is 250. Say next conversion reads 900. (900/4=225). SO, program draws coloured line now on VDU, from position 250 to 225. Next conversion from 225 to next position, and so on. PLEASE EXCUSE if any of this is ground you are very familiar with. Well Jim, I hope this will give you some food for thought, and help a bit. You've hit upon my FAVOURITE seismo topic.....final aim is to have 3 D hologram, showing 3D movement of earth particals, in real time or speeded up.....will probably start with a suspended table tennis ball attached to 3 servo motors . I first become interested in the above when I read a book on seismology written by the father of English seismology, Prof. Milne, in 1898 (!!). He used smoked glass to record upon, and produced great traces showing the movement of the earth as seen from above. I thought that my PC was better equiped than smoked glass , so that is what started me down this particular road to Three Dimensions. Happy T H R E E-DIMENSIONAL SEISMO'ING!! .. Regards, Albert Noble. Jim Hannon wrote: > prewar wrote: > > > With a vertical seismo in-tow with the 2 horizontals, I hope to > > have a Three-Dimensional seismograph. Software will show SECTIONS both > > through earth NS and EW, and also PLAN of earth movements, in addition > > to normal o/p traces on VDU etc. All Hall-Effect sensing + 12 bit A/D. > > > > I would be very interested in hearing more about how you plan on viewing > the 3d data. I am working on a 3 axis instrument with each axis having > identical response. But I haven't any good ideas on viewing the data. > > -- > Jim Hannon > http://soli.inav.net/~jmhannon/ > 42,11.90N 91,39.26W > WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: Heating enclosures. Date: Mon, 13 Oct 1997 13:44:25 +0100 Hello Dave, Yes, I have an acrylic frontage to the enclosure, but many have pointed out that my heating is excessive, so I am having a rethink. I thought that 1 lightbulb would give too concentrated a heat.....I do use 4x40w light bulbs to heat my insulated hut though, but the seismos are seperately enclosed. Thanks for suggestions from you, and all. Regards, Albert Noble (England) David A. Nelson wrote: > Albert Did you think about just using a 60W lightbulb, If your > enclosure is metal you could put a perspex window in it and the light > would let you keep an eye on the inside without having to remove the cover. > > Dave > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Doug Crice Subject: Re: Heating enclosures. Date: Mon, 13 Oct 1997 08:21:02 -0700 re: Heating your seismometers I would think it would be better to use DC instead of AC to heat seismometers, at least if anybody has problems with 50/60 Hz noise. I also think that a variable resistance temperature control would be better than a thermostat, both to keep the temperature constant and to eliminate the transient from the switch. There are some relatively cheap thermistors big enough to do this job in electronics catalogs. Doug Crice _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: Heating enclosures. Date: Mon, 13 Oct 1997 10:00:26 -0700 Another thought for self regulating heaters is to use PTC's (also called Posistors). This is becoming the mechanism of choice for coffee brewers. The PTC is self limiting in temperature. So it smoothly transitions to a given temperature which is set by the design of the PTC itself. No EMI! They're not terribly accurate, but they are simplicity themselves. For instance I looked up one available PTC heater from Keystone Thermometrics, St.Marys, PA 15857, phone 814-834-9140 and 800-246-7019. A part number 5510-25-65-120-PTH is a 120 V 65 degree C 20 W disc .55" dia and 0.1" thick. Another company in addition to Keystone that I'm aware of that makes heater type PTC's and that you might have some luck with in small quanities is Therm-O-Disc, Inc., Midwest Components Product Group, Muskegon, MI phone 616-777-4100. I also believe TDK, Murata, and Philips components among others, make heater versions of PTC's, but they are hard to deal with unless you have a volume application or work for a big company where the salesman can slip you some samples. There are many others that supply instrument size PTC's for use in sensing applications and certain types of current limiting and resettable fuse applications. I know I've seen some of the surplus catalogs with the coffee pot elements for sale. The problem here is that they are probably set for about 120 degrees C. A bit high for your use. Electronic parts store that cater to the TV repair area usually had some PTC's that were used on color TV sets to control the deguassing coil. They would allow an amp or two to flow for a few seconds when the TV was first turned on, then due to self heating would shut down to a few milliamps while the set remained on. What their setting temperature was, I have no idea -- just the place for a quick experiment, don't you think? Anyway, good luck. Charles R. Patton _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roger Baker Subject: Re: Heating enclosures. Date: Mon, 13 Oct 1997 12:06:39 -0500 Friends, With respect to most sensitive, high resolution instrumentation, thermal drift is the #1 problem limiting measurement accuracy. Two main design options for temperature control are a variable resistor, usually a transistor in series with the heater -- versus pulse width modulated heating which is actually a very rapid on-off control. The latter is very efficient since there is very little resistive heating in the control transistor, since the power is either full on or off. You can often operate this circuit above the top frequency of the sensor. (With very small sensor packages, the transistor itself can be used as a heater, which is both convenient and efficient.) My current approach for moderately sized sensors such as my *jellybean* seismometer/gravimeter is to use pulse width modulated heaters. The heater is arrays of evenly spaced small 100 ohm or so resistors glued with silicone to the outside of the aluminum box sensor enclosure, which is then encased in styrofoam. The best temperature control and uniformity comes from having alternating layers of good thermal conductors like aluminum and poor thermal conductors like styrofoam. If possible, try to design for small size because gradients and other thermal problems increase rapidly with instrument size. Put your front end electronics in the same thermally controlled box with the sensor. Attach your thermal sensor directly to part of the heater so the thermal lag of the feedback loop is minimized. The accuracy of the system is often increased is there is standby power going into the heater so the control power merely power tops off this constant level of heat input. Also you can't get good thermal control with a low gain feedback loop; accuracy is increased as you turn up the electronic gain of the thermal feedback loop -- usually until the system becomes unstable and starts hunting or oscillating in temperature. For REALLY precise temperature control, there is not much alternative but to use several concentrically enclosed stages of rough control and precision control. Standard little Radio Shack thermistors can probably be made to sense levels of microdegrees near room temp with appropriate support circuitry and seem to work plenty well enough for most practical sensing purposes such as thermal feedback controls. --Yours, Roger Baker _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: Heating enclosures. Date: Mon, 13 Oct 1997 16:45:39 +0100 Yes Doug, Hadn't thought about AC noise....now having a rethink here. Thanks for advice from you, and everyone else, who responded to my first letter. Regards...Albert Noble. Doug Crice wrote: > re: Heating your seismometers > > I would think it would be better to use DC instead of AC to heat > seismometers, at least if anybody has problems with 50/60 Hz noise. I > also think that a variable resistance temperature control would be > better than a thermostat, both to keep the temperature constant and to > eliminate the transient from the switch. > > There are some relatively cheap thermistors big enough to do this job in > electronics catalogs. > > Doug Crice > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Brian Chesire Subject: Re: Heating enclosures. Date: Mon, 13 Oct 1997 11:31:23 -0700 Hi, A fairly good temperature contoller is the National LM3911. I've used these for everything from milliwatt heaters to 6.5KW heaters. Very versatile. The National data sheet covers it pretty well. Properly designed it can give you a very tight loop. However, When I needed really tight control, at temps over 80C, I used a pretty standard thermistor proportional circuit. This was for a precision oscillator, ie. crystal oven. The LM3911 controls the outer oven, at 55C, and the thermistor the inner. The control circuitry for the inner oven is mounted inside the outer oven which really helps overall stability. Brian, Tucson, AZ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Daryl P. Dacko" Subject: Re: Heating enclosures. Date: Mon, 13 Oct 1997 19:19:12 -0400 At 10:00 AM 10/13/97 -0700, you wrote: >Another thought for self regulating heaters is to use PTC's (also called >Posistors). This is becoming the mechanism of choice for coffee >brewers. The PTC is self limiting in temperature. So it smoothly >transitions to a given temperature which is set by the design of the PTC >itself. No EMI! They're not terribly accurate, but they are simplicity >themselves. I've used them myself to regulate temperature on a drift-sensitive transister. They work just fine if you don't need very percise control, although I've seen mine control to within .1 deg C in an insulated oven. If you want more BTU's, just thermally bond them to a heatsink located near the top of the box. I know Newark Electronics carrys them, and for the folks overseas, Farnell could likely get them too, since they are the same company... A great idea, I didn't think of useing them in this application. It's a real boon to us folks where it's blistering hot in the summer and bitter cold in the winter - automatic heat without the expensive controller ! Daryl _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: detectable distance Date: Mon, 13 Oct 1997 15:33:26 -0700 At 01:06 PM 10/12/97 -0700, Clark Wockner wrote: >Hi all: > I seem to be missing most of the quakes others are getting. Is it >because most seismic zones are so far from Illinois or is it because of >some other reason? I did not record the Kermadek 6.9 a while back and I >was sure I should have gotten it. What kind of distance are the rest of >you getting with your Lehmans? Comments please. > Thanks all > It could just be the distance, but you should also check the period of your sensor. If its not long enough you will not pickup the long period surface waves. I had this problem with my Lehman a while back. I wasn't getting much low freq. information so I checked the period. Sure enough, it was down to something like 6 seconds. It should have been around 16 to 20 seconds. It must have changed do to all of the re-adjustment I keep having to do to it, do to the tilting problem. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: TESMECO@....... Subject: Re: Ruapehu Date: Mon, 13 Oct 1997 21:04:06 -0400 (EDT) looking forward to see if it will blow i hope there isnt any body to close when and if it dose thans for the history TIM. SO CAL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: THREE DIMENSIONAL Seismograghs and software. Date: Mon, 13 Oct 1997 06:58:09 -0700 Hi All I haven't been following the Three Dimensional thread in detail but I think (in theory) if one has the three components of an arriving wave that it should be possible to determing the direction the wave is coming from by vector analysis. With the addition of the arrival times, one could "pinpoint" the epicenter from one station. In reality I think the waves from three directions could get pretty complicated for other than local events. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Al Allworth Subject: Re: Heating enclosures. Date: Mon, 13 Oct 1997 19:06:58 -0700 (PDT) At 12:06 PM 10/13/97 -0500, you wrote: > >Friends, > With respect to most sensitive, high resolution instrumentation, >thermal drift is the #1 problem limiting measurement accuracy. > Hello group, 25 years ago I designed a temperature control which might be of interest here. The company I was working for determined the circuit to be patentable but the project we were working on was canceled and the rights were assigned to me. I didn't have the money to patent it and people were not using accurate ovens for electronics circuits any more so it never went anywhere. The temperature sensor and the heating element are one and the same. The heater is in the form of a bridge with oposite legs made of Iron wire and the other pair of Manganin wire, which has close to zero temperature coeficient. The midpoints of the bridge are connected to a diferential amplifier which drives a series transistor feeding the bridge heater from the power supply. I was able to get a temperature stability with a single enclosure of better that 1/10 of a degree with the outside temperature changing from 0 degrees to 75 degrees F. I would be happy to see someone put this to practical use. Al _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: JIM CRISTIANO Subject: Re: detectable distance Date: Mon, 13 Oct 1997 20:36:16 -0700 Larry Cochrane wrote: > It could just be the distance, but you should also check the period of your > sensor. If its not long enough you will not pickup the long period surface > waves. I had this problem with my Lehman a while back. I wasn't getting > much low freq. information so I checked the period. Sure enough, it was > down to something like 6 seconds. It should have been around 16 to 20 > seconds. It must have changed do to all of the re-adjustment I keep having > to do to it, do to the tilting problem. Nothin' like an old wood floor for some ultra slow rockin' and rollin'! Jim cristiano@........... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: New Station on the USA map Date: Tue, 14 Oct 1997 20:41:41 +1200 Hi all, Please welcome Robert Laney from Herndon, Va, to the group. It's good to see another east coast seismic station up and running, look for him on the USA map on my pages. Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: MONSTER QUAKE STH PAC Date: Tue, 14 Oct 1997 22:08:13 +1200 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Paul Subject: Re: MONSTER QUAKE STH PAC Date: Tue, 14 Oct 1997 03:50:26 -0700 Dave-- What happened in the South Pacific. I am VERY concerned about anything down there, as contrary to popular theory I sincerely believe in the 'ringing bell' hypothesis, and that anything big that happens on the west side of my little Pacific plate can and will have repercussions over here in LA to NW on the other side of the rim.... Any info yet? Stephen :^) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: MONSTER QUAKE STH PAC Date: Tue, 14 Oct 1997 23:03:58 +1200 Stephen, still waiting for posting to USGS bulletin page. event ~5.5 minutes from my which puts it in the New Calidonia =---- Fiji regional distance and the amplitude suggests M7.9 --- 8.5 largest amplitude I have recorded for this distance. Tony in Hawaii mailed me a short time ago He also recorded it with large amplitude (largest he has so far recorded Dave At 03:50 AM 10/14/97 -0700, you wrote: >Dave-- > >What happened in the South Pacific. I am VERY concerned about anything >down there, as contrary to popular theory I sincerely believe in the >'ringing bell' hypothesis, and that anything big that happens on the west >side of my little Pacific plate can and will have repercussions over here >in LA to NW on the other side of the rim.... > >Any info yet? > >Stephen :^) > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: peaches@............ (Donna Whitaker) Subject: Re: MONSTER QUAKE STH PAC Date: Tue, 14 Oct 1997 01:17:11 -1000 (HST) Dave, CDIDC has it in the Fiji Islands region at M6.2 but thats got to be way low. Tony >Stephen, > still waiting for posting to USGS bulletin page. > > event ~5.5 minutes from my which puts it in the New Calidonia =---- Fiji >regional distance and the amplitude suggests M7.9 --- 8.5 largest >amplitude I have recorded for this distance. > > Tony in Hawaii mailed me a short time ago He also recorded it with >large amplitude (largest he has so far recorded > >Dave > > >At 03:50 AM 10/14/97 -0700, you wrote: >>Dave-- >> >>What happened in the South Pacific. I am VERY concerned about anything >>down there, as contrary to popular theory I sincerely believe in the >>'ringing bell' hypothesis, and that anything big that happens on the west >>side of my little Pacific plate can and will have repercussions over here >>in LA to NW on the other side of the rim.... >> >>Any info yet? >> >>Stephen :^) >> >> >> >>_____________________________________________________________________ >> >>Public Seismic Network Mailing List (PSN-L) >> >>To leave this list email listserver@............. with the body of the >>message: leave PSN-L >> >> > >Co-ordinator: >New Zealand >Public Seismic Network > Dave A. Nelson ZL4TBN > 24 Jensen St., > Green Is., Dunedin, > South Is.. New Zealand. > >http://psn.quake.net/dave/home.htm > >IF there indeed are other parallel universes... I can now rest in the >knowledge, that in at least one of them, I am filthy rich and drive a red >Ferrari > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: lahr@................. (Dr. John Lahr (USGS-GI Seismologist)) Subject: Monster Quake Date: Tue, 14 Oct 1997 03:27:59 -0800 Here is what Palmer, Alaska, got. JCLahr > From atwc@.......... Tue Oct 14 03:12:41 1997 > From: atwc@.......... > Date: Tue, 14 Oct 97 10:44:59 GMT > To: tsunami@.............. thomasville.moc@......... > incident_information_@................ alert@........... > oemd@................ ecc@.......... > tsunami_&_pacific_eqs@................ Mary.Edwards@......... > ap@........... pamela_bergmann@............ jstorm@.................. > atwc@.................. avo-Anc@................... aeboro@........... > oes@.............. 0001032943@............ > bob_stewart@.................... R7AIUWR@............. > editor@........... havinfun@........... kiro@............ > paul@................. lrayment@.......... lad1@................. > gfdurocher@......... ruth.barritt@......... watson@................. > char@............... bgoldenberg@.............. marlins@........... > Cc: atwc@.......... > Subject: Tsunami Bulletin > > > > > TSUNAMI BULLETIN NUMBER 1 > WEST COAST AND ALASKA TSUNAMI WARNING CENTER/NOAA/NWS > ISSUED OCT 14 AT 1041 UTC > > ...THIS IS A TSUNAMI INFORMATION BULLETIN FOR ALASKA, BRITISH > COLUMBIA, WASHINGTON, OREGON, AND CALIFORNIA ONLY... > NO, REPEAT NO, WATCH OR WARNING IS IN EFFECT. > AN EARTHQUAKE, PRELIMINARY MAGNITUDE 7.1, OCCURRED AT > 0153 ADT ON OCT 14, OR 0253 PDT ON OCT 14, OR 0953 UTC ON OCT 14. > THE EARTHQUAKE WAS LOCATED IN THE GENERAL AREA OF: > TONGA IS. NEAR 21.9S, 176.7W. > THE PACIFIC TSUNAMI WARNING CENTER WILL ISSUE A TSUNAMI > INFORMATION BULLETIN FOR HAWAII AND OTHER AREAS OF THE PACIFIC. > EVALUATION: BASED ON LOCATION AND MAGNITUDE THE EARTHQUAKE WAS > NOT SUFFICIENT TO GENERATE A TSUNAMI DAMAGING TO CALIFORNIA, > OREGON, WASHINGTON, BRITISH COLUMBIA OR ALASKA. SOME AREAS MAY > EXPERIENCE SMALL SEA LEVEL FLUCTUATIONS. > THIS WILL BE THE ONLY BULLETIN ISSUED FOR THIS EVENT BY THE > WEST COAST AND ALASKA TSUNAMI WARNING CENTER UNLESS CONDITIONS > WARRANT.IF AVAILABLE, REFER TO THE INTERNET SITE (USE LOWER CASE) > HTTP://WWW.ALASKA.NET/(TILDA)ATWC FOR MORE INFORMATION. > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: MONSTER QUAKE STH PAC Date: Tue, 14 Oct 1997 23:39:43 +1200 I have been fooled in the past..... sometimes on a really deep event you get larger amplitude because of the lower attenuation between the epic and my recorder as a result a questimate mag. that is a bit high but M6.2 seems too low for this distance one that size and dist. would only just be detectable for me. plus I suspect that it may not be extremely deep as I recorded the LR (Rayleigh) surface waves I'm still picking the final result will be in the high 7's a bit dangerous to put money on it though..... Dave At 01:17 AM 10/14/97 -1000, you wrote: >Dave, >CDIDC has it in the Fiji Islands region at M6.2 >but thats got to be way low. > >Tony Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Monster Quake Date: Tue, 14 Oct 1997 23:46:59 +1200 Thanks John, USGS bulletin just released 97/10/14 09:53:18 21.95S 176.92W 166.2 6.5Mb FIJI ISLANDS REGION SE of Fiji in the Tongan Is. Dave At 03:27 AM 10/14/97 -0800, you wrote: >Here is what Palmer, Alaska, got. > >JCLahr > >> From atwc@.......... Tue Oct 14 03:12:41 1997 >> From: atwc@.......... >> Date: Tue, 14 Oct 97 10:44:59 GMT >> To: tsunami@.............. thomasville.moc@......... >> incident_information_@................ alert@........... >> oemd@................ ecc@.......... >> tsunami_&_pacific_eqs@................ Mary.Edwards@......... >> ap@........... pamela_bergmann@............ jstorm@.................. >> atwc@.................. avo-Anc@................... aeboro@........... >> oes@.............. 0001032943@............ >> bob_stewart@.................... R7AIUWR@............. >> editor@........... havinfun@........... kiro@............ >> paul@................. lrayment@.......... lad1@................. >> gfdurocher@......... ruth.barritt@......... watson@................. >> char@............... bgoldenberg@.............. marlins@........... >> Cc: atwc@.......... >> Subject: Tsunami Bulletin >> >> >> >> >> TSUNAMI BULLETIN NUMBER 1 >> WEST COAST AND ALASKA TSUNAMI WARNING CENTER/NOAA/NWS >> ISSUED OCT 14 AT 1041 UTC >> >> ...THIS IS A TSUNAMI INFORMATION BULLETIN FOR ALASKA, BRITISH >> COLUMBIA, WASHINGTON, OREGON, AND CALIFORNIA ONLY... >> NO, REPEAT NO, WATCH OR WARNING IS IN EFFECT. >> AN EARTHQUAKE, PRELIMINARY MAGNITUDE 7.1, OCCURRED AT >> 0153 ADT ON OCT 14, OR 0253 PDT ON OCT 14, OR 0953 UTC ON OCT 14. >> THE EARTHQUAKE WAS LOCATED IN THE GENERAL AREA OF: >> TONGA IS. NEAR 21.9S, 176.7W. >> THE PACIFIC TSUNAMI WARNING CENTER WILL ISSUE A TSUNAMI >> INFORMATION BULLETIN FOR HAWAII AND OTHER AREAS OF THE PACIFIC. >> EVALUATION: BASED ON LOCATION AND MAGNITUDE THE EARTHQUAKE WAS >> NOT SUFFICIENT TO GENERATE A TSUNAMI DAMAGING TO CALIFORNIA, >> OREGON, WASHINGTON, BRITISH COLUMBIA OR ALASKA. SOME AREAS MAY >> EXPERIENCE SMALL SEA LEVEL FLUCTUATIONS. >> THIS WILL BE THE ONLY BULLETIN ISSUED FOR THIS EVENT BY THE >> WEST COAST AND ALASKA TSUNAMI WARNING CENTER UNLESS CONDITIONS >> WARRANT.IF AVAILABLE, REFER TO THE INTERNET SITE (USE LOWER CASE) >> HTTP://WWW.ALASKA.NET/(TILDA)ATWC FOR MORE INFORMATION. >> > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Monster Quake Date: Wed, 15 Oct 1997 00:01:07 +1200 Here's the CMT from CALTECH Dave Subject: CMT Mw=7.7 FIJI ISLANDS REGION General region : FIJI ISLANDS REGION surface waves (3.0,3.5,7,7.5 mHz) Stations used : COR KEV KIP NWAO SNZO TUC Origin time: 1997 287 9 53 18 Original location (lat,lon,depth) : -22.0000 -176.900 166 Moment tensor (x1.e26 dyncm) : Mrr : -11.017150 Mtt : 9.056068 Mff : 1.961082 Mrt : -9.261573 Mrf : -37.574108 Mtf : 14.807621 T-axis: moment= 42.549 plunge= 34.189 azimuth= 123.744 N-axis: moment= 0.235 plunge= 19.560 azimuth= 19.776 P-axis: moment= -42.784 plunge= 49.148 azimuth= 265.517 best double couple: Mo= 42.667(x1.e26 dyncm) Mw=7.7 tau= 19.4 nodal planes (strike/dip/slip): 16.95/ 82.10/-109.76 266.00/ 21.22/-22.33 Centroid location : -21.737 -176.628 170.152 Centroid time : 17.691 Variance reduction (%) : 78 *********** **** o**** *** oooooooooooo---*** ** ooooo oooooo--** ** ooo oo----oooo** * ooo o--------ooo* * oo o----------oo* **o oo-----------o** *o o-------------o* **o oo--------------** ** P + o---------------** ** oo---------------** * oo----------------* ** o----------------** * oo---------T------* * oo----------------* ** o---------------** ** o---------------** *** oo------------*** ****oo---------**** *********** Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Thermal Accelerometers Date: Tue, 14 Oct 1997 10:40:41 -0500 I saw a Humphrey Inc. add in Sensors magazine. They descirbe a thermal accelerometer based an heat transfer no moving parts or fluids. Does anyone know how this works? Jim Hannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Erich F. Kern" Subject: Re: Thermal Accelerometers Date: Tue, 14 Oct 1997 09:07:46 -0700 Hi Jim, Thermal sensor elements within the sealed package detect changes in convection currents due to acceleration. Charles Patton and I have been working on a 2 axis seismograph using the Humphrey device. Its noise floor is 2 orders of magnitude lower than the analog devices ADXL05, but probably not low enough to detect teleseismic events. Freq. response goes to D.C., so it makes a very sensitive tilt detector as well. Humphrey's 4 page data sheet can be downloaded from our web page. See the address below. Regards, Erich *************************************************************** Please visit our web site at: http://www.dconn.com/FatQuartersSoftware Thank you *************************************************************** ---------- > From: James M Hannon > To: PSN-L@............. > Subject: Thermal Accelerometers > Date: Tuesday, October 14, 1997 08:40 > > > > > > I saw a Humphrey Inc. add in Sensors magazine. They descirbe a thermal > accelerometer based an heat transfer no moving parts or fluids. Does > anyone know how this works? > > > Jim Hannon > > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: Thermal Accelerometers Date: Tue, 14 Oct 1997 09:29:23 -0700 This is the same sensor Erich Kern and I used in the experimenter article I did for the Geo-Monitor which ended up with about a 30 uG p-p noise floor and thus a continuous full range of +- 15 ug to +- 2 g. Go to: http://patent.womplex.ibm.com and look up: 5581034 : Convective accelerometer and inclinometer ABSTRACT: A convective accelerometer and inclinometer includes two temperature sensing elements mounted within a sealed enclosure containing a gas. The application of heat to the gas within the enclosure by a heating element causes the gas to flow in a predetermined pattern in free convection. When linear acceleration or inclination is applied to the enclosure the convective flow of gas is affected causing a temperature differential between the temperature sensing elements. This temperature differential is measured as a difference in electrical resistance between the two temperature sensing elements which is proportional to the acceleration. The device can be used to measure linear acceleration, velocity, position or inclination. The device can also be used as an inclinometer for measuring the angle of gravity. The device has a wide variety applications particularly within the automotive field. If you want more, you can click on the "View Images" icon and get the whole thing. Charles R. Patton patton@......... James M Hannon wrote: > I saw a Humphrey Inc. add in Sensors magazine. They descirbe a thermal > accelerometer based an heat transfer no moving parts or fluids. Does > anyone know how this works? > > Jim Hannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: 3D and earth partical direction Date: Tue, 14 Oct 1997 18:30:01 +0100 Jim Hannon wrote: > I would be very interested in hearing more about how you plan on viewing > the 3d data. I am working on a 3 axis instrument with each axis having > identical response. But I haven't any good ideas on viewing the data. > Hi Jim again, Further to my suggestions, in answer to the above...... It occured to me that you may like to show your 3 dimensional o/p's in the following manner. It would be a show for family, friends and the local science museums, to show youngsters what the moving earth beneath their feet, REALLY looks like. First, let us suppose that when you are viewing your monitor, that you are facing NORTH. If you can program, write in the following patch as item 9 on my previous selection list. If you cannot program PC's, I see from the archives, (yes, I'm still struggling to read through them ALL!), that there are many folk in your part of the world on the PSN, who can program PC,s. Draw a circle or ball on screen ( this is representative of an earth partical), whose DIAMETER is directly controlled by the A/D o/p from the N/S seismo. It's vertical position on the screen is controlled by the A/D o/p from the VERT seismo, and whose lateral position on the screen is controlled by the A/D o/p from the E/W seismo. Program to hold all coordinates in 3 variables, and ERASE circle or ball at end of each A/D conversion. Then simply redraw at new positions, and new diameter at next set of coordinates, given by all 3 new A/D conversions. Repeat this process until the wife asks, 'When are you going to pack up watching that VDU?' . ALSO, as the circle or ball grows smaller ,(earth particals moving to the NORTH), program to slowly increase the BLUE o/p on the redraw colour. Conversly, as ball/circle grows larger,(earth particals moving to the SOUTH), program to increase the RED o/p on the redraw colour. I suggest these particular colours, because as things receed they become lost in a BLUE mist, and as they approach, they become brighter, and more potent looking. So RED. If your monitor faces, say, EAST, then VERT seismo still controls vert position on screen. BUT this time, of course, the ball/circle DIAMETER/COLOUR is controlled by the A/D o/p from the E/W seismo, (ball getting smaller on earth movement to the EAST, and larger to the WEST) . The N/S seiemo now controlling the lateral position on the ball/circle.......and so on. If you wish to lay in bed with monitor up on the ceiling, then the diameter of the ball/circle will be controlled by the VERT seismo...well it takes all sorts I Hope that all above is clear......please give us a shout if not. Now, comes the real 'party piece'......... Replay all those great tremors which you hold on Hard Disc, taken from your 3 dimensional seismos, at x2, x10, x100 normal speed, or anything you wish. Now watch the youngsters eyes as the 'ball' wizzes around, as a TRUE replay of how the earth REALLY moved, on the day that the ornament fell of the shelf . Also program for TWO balls/circles to compare various 'events' with each other, from two earthquake files together on HD. NONE of the programming above is too difficult, but the results may be worth watching.....I bet you can't wait to get all of your 3D seismos up and running now, Jim........don't forget that ALL 3 seismos must be calibrated for equal volts out for equal movement, but I believe that you are doing this. Yes, Barry as you say, direction may be seen with 3D, certainly for NEAR events. Just watch the coloured ball ,and it will show you!!! Regards, Albert Noble. (England) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: APOLOGY Date: Tue, 14 Oct 1997 19:12:48 +0100 Hello all, Have just read letters about your large earthquake. In view of this, my remarks about falling ornament off shelf, in my letter to Jim an hour ago, was in very bad taste, and I apologise for making it. Regards...Albert Noble. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: lahr@................. (Dr. John Lahr (USGS-GI Seismologist)) Subject: 3D Date: Tue, 14 Oct 1997 10:38:35 -0800 Albert, Another way to get the in-and-out direction would be with 3D colored glasses. Each ball would be drawn twice, once in red and once in blue. Use zero seperation for the circles when the ball is in the plane of the screen and increase the separation linearly one way for into the screen locations and the other way for out of the screen location. Viewed with 3D glasses the ball will appear to move in and out of the screen as well as laterally. I wrote a program in the DOS-Turbo Pascall-days that would display a rotating wire frame figure this way and it worked well. JCLahr ################################## John C. Lahr ################################# Seismologist ################################ U.S. Geological Survey ############################### c/o Geophysical Institute ############################## 903 Koyukuk Drive ~~~~~~~~~~~~~~ Get ~~~~~~~~~~ ############################# ########################################################### P.O. Box 757320 ################################ Fairbanks, AK 99775 ################################# Phone: (907) 474-7997 ################################## Fax: (907) 474-5618 ~~~~~~~~ the thrust? ~~~~~~~~~~~~~~ lahr@........ #################################### http://www.aeic.alaska.edu/Input/lahr/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: lahr@................. (Dr. John Lahr (USGS-GI Seismologist)) Subject: Re: THREE DIMENSIONAL Seismograghs and software. Date: Tue, 14 Oct 1997 12:40:47 -0800 Barry Lotz writes: "Hi All I haven't been following the Three Dimensional thread in detail but I think (in theory) if one has the three components of an arriving wave that it should be possible to determing the direction the wave is coming from by vector analysis. With the addition of the arrival times, one could "pinpoint" the epicenter from one station. In reality I think the waves from three directions could get pretty complicated for other than local events." This is a good technique for teleseismic events within about 90 degrees distance. If you think about the particle motion of the P-phase as being along the travel path between your station and the earthquake, then you can see, for example, that if the motion of the P-phase is up, south, west, then the earthquake came from the northeast. If the motion is down, north, west, then the earthquake came from the event came from the northwest. Up motion always points away from the source and down motion points toward the source. The first motion of the P-phase is the best part of the seismic signal to use this technique on, as the very first waves to arrive have come by a direct path. If you can identify the S phase, then the distance can be computed VERY roughly by (S - P - 2)*10 ~ distance in degrees. Measure the time between P and S in minutes, subtract 2 mintues, then multiply by 10 to get the distance in degrees. I put a travel-time table on my web site at: http://www.giseis.alaska.edu/Input/lahr/tttable.gif JCLahr ################################## John C. Lahr ################################# Seismologist ################################ U.S. Geological Survey ############################### c/o Geophysical Institute ############################## 903 Koyukuk Drive ~~~~~~~~~~~~~~ Get ~~~~~~~~~~ ############################# ########################################################### P.O. Box 757320 ################################ Fairbanks, AK 99775 ################################# Phone: (907) 474-7997 ################################## Fax: (907) 474-5618 ~~~~~~~~ the thrust? ~~~~~~~~~~~~~~ lahr@........ #################################### http://www.aeic.alaska.edu/Input/lahr/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Caruso Subject: Re: Thermal Accelerometers Date: Tue, 14 Oct 1997 18:51:56 -0400 (EDT) Check out ELECTRONICS NOW recent issue on thermal wind speed measure? STEPHEN CARUSO CET KB8UGH _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Seismograghs and software. Date: Wed, 15 Oct 1997 11:48:31 +1200 John, just been playing with the phase arrival time setup on your pages interesting.... there must be some differences in you calc. methods to what Larry uses in Winquake. eg. here is the data from your calc. DATE-(UTC)-TIME LAT LON DEPTH MAG Q COMMENTS 97/10/14 09:53:18 21.95S 176.92W 166.2 6.5Mb A FIJI ISLANDS REGION delta azimuth (degrees clockwise from north) (deg) eq-to-station station-to-eq 25.92 200.4 27.6 travel arrival time # code time(s) dy hr mn sec 1 P 316.61 0 9 58 34 2 P 320.80 0 9 58 38 3 S 575.14 0 10 2 53 4 PKiKP 980.06 0 10 9 38 Questions there are two "P" times ? you have delta deg and station to eq deg what is the difference ? Now the distance calc. by WQ for the distance between me and the epic. is is 2886 km or 25.95 deg (which is your delta deg. measurement). TNX Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: Seismographs and software. Date: Tue, 14 Oct 1997 16:20:22 -0700 At 11:48 AM 10/15/97 +1200, Dave Nelson wrote: Please note that there is a bug in some of the newer releases of WinQuake around the azimuth calculation in the Great Circle Distance calculator dialog box. If you have a new version of WQ, I not sure exactly what version this bug started showing up in, with the GC dialog box that has both the azimuth to and from the event, then you should not rely on the azimuth numbers. One of them is bogus. I have a beta release ready that has this bug fixed. It also has two new features that some may find useful. I'm going to be announcing the new release later tonight. -Larry Cochrane Redwood City, PSN >John, > just been playing with the phase arrival time setup on your pages > interesting.... there must be some differences in you calc. methods to >what Larry uses in Winquake. > >eg. here is the data from your calc. > > DATE-(UTC)-TIME LAT LON DEPTH MAG Q COMMENTS > 97/10/14 09:53:18 21.95S 176.92W 166.2 6.5Mb A FIJI ISLANDS REGION > > delta azimuth (degrees clockwise from north) > (deg) eq-to-station station-to-eq > 25.92 200.4 27.6 > > travel arrival time > # code time(s) dy hr mn sec > 1 P 316.61 0 9 58 34 > 2 P 320.80 0 9 58 38 > 3 S 575.14 0 10 2 53 > 4 PKiKP 980.06 0 10 9 38 > > Questions there are two "P" times ? > you have delta deg and station to eq deg what is >the difference ? > > Now the distance calc. by WQ for the distance between me and the epic. is > is 2886 km or 25.95 deg (which is your delta deg. measurement). > >TNX >Dave > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: New event? Date: Tue, 14 Oct 1997 07:33:06 -0700 Hi all Is another event coming in? @ 10/15/97 01:03:40 UTC??? Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: New event? Date: Wed, 15 Oct 1997 14:42:47 +1200 yes there is Barry I recorded it here in NZ Dave At 07:33 AM 10/14/97 -0700, you wrote: >Hi all > Is another event coming in? @ 10/15/97 01:03:40 UTC??? > Barry > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: yet another large event Date: Wed, 15 Oct 1997 17:21:41 +1200 Aleutians this time Dave Subject: CMT Mw=6.3 ANDREANOF ISLANDS, ALEUTIAN IS. General region : ANDREANOF ISLANDS, ALEUTIAN IS. surface waves (3.0,3.5,7,7.5 mHz) Stations used : COR KBS KEV NWAO TATO TUC Origin time: 1997 288 3 11 11 Original location (lat,lon,depth) : 51.3000 -177.700 31 Moment tensor (x1.e26 dyncm) : Mrr : 0.497063 Mtt : -0.184046 Mff : -0.313017 Mrt : -0.063278 Mrf : -0.005620 Mtf : 0.002294 T-axis: moment= 0.503 plunge= 84.720 azimuth= 175.564 N-axis: moment= -0.190 plunge= 5.269 azimuth= 359.174 P-axis: moment= -0.313 plunge= 0.331 azimuth= 269.144 best double couple: Mo= 0.408(x1.e26 dyncm) Mw=6.3 tau= 4.1 nodal planes (strike/dip/slip): 353.87/ 44.91/ 82.53 184.36/ 45.57/ 97.39 Centroid location : 51.319 -178.244 72.095 Centroid time : 20.920 Variance reduction (%) : 1 Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: yet another large event Date: Wed, 15 Oct 1997 17:32:17 +1200 Aleutians this time Dave Subject: CMT Mw=6.3 ANDREANOF ISLANDS, ALEUTIAN IS. General region : ANDREANOF ISLANDS, ALEUTIAN IS. surface waves (3.0,3.5,7,7.5 mHz) Stations used : COR KBS KEV NWAO TATO TUC Origin time: 1997 288 3 11 11 Original location (lat,lon,depth) : 51.3000 -177.700 31 Moment tensor (x1.e26 dyncm) : Mrr : 0.497063 Mtt : -0.184046 Mff : -0.313017 Mrt : -0.063278 Mrf : -0.005620 Mtf : 0.002294 T-axis: moment= 0.503 plunge= 84.720 azimuth= 175.564 N-axis: moment= -0.190 plunge= 5.269 azimuth= 359.174 P-axis: moment= -0.313 plunge= 0.331 azimuth= 269.144 best double couple: Mo= 0.408(x1.e26 dyncm) Mw=6.3 tau= 4.1 nodal planes (strike/dip/slip): 353.87/ 44.91/ 82.53 184.36/ 45.57/ 97.39 Centroid location : 51.319 -178.244 72.095 Centroid time : 20.920 Variance reduction (%) : 1 Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: New beta release of WinQuake and SDR. Date: Tue, 14 Oct 1997 22:04:27 -0700 Greetings, I just got finished with the next release of WinQuake, version 2.5, and would like some beta testers to try it out. I also have a new beta release of SDR, version 2.4, that goes along with the WQ release. The WinQuake release has two new features and some bug fixes. The two bug fixes are: The Great Circle Distance Calculate dialog box was displaying bogus numbers for the azimuth calculation. Thanks to Robert Barns for reporting this bug. The second bug was around the Data Integration feature. On 16 bit versions it would crash on some event files. Thanks to Bob Lewis for reporting this one. The two new features are both network related. If you are going to try this release please save this email message. Its the only documentation I have for the new features. The first feature allows the user to directly access report information over the Internet. It uses the UNIX finger service (TCP/IP port 79) to get report information directly from the source. This report information has event information (location, time of origin etc) that can be used to update event files. Before you had to use some other method to get the report into a file local to the system and then have WinQuake read it in. With this new feature all you have to do is select the finger server/host in a dialog box and WinQuake will retrieve the information directly over the Internet. It save the report/finger information in a file and then parse out the event information and displays it in a list box. The report information can then be used to fill in the header information of an event file or used in the second new feature below. There's one big problem... This feature is only supported in the 32 bit version. For WinQuake to access information over the Net it needs to have access to sockets. The sockets under Win95 and NT are easier to deal with. Since the 16 bit version of Windows is now obsolete I'm not going to spend anytime supporting it. Sorry... To use this feature all you need to do is go to the Report dialog box. You can use the Report tool bar icon or the File / Report menu item to open this dialog box. There you will see a new button called "Load Network Report". This button is grayed-out in the 16 bit version. After selecting this button you will see a new dialog box. If you have the NETWORK.DAT file in the same directory as WQ you should a list of finger commands/host names in the list box. If you double click (or use the "Connect" button) on one, WQ should attempt to connect to the finger server and download the file. Obviously you will need to be logged onto the net to get any data back. If everything works as planed the dialog box will close up when it finishes collecting the data. The Report dialog report list should now have the new event information in it. If there are any errors, the Network dialog box will stay open and an error message should show up in the Status line. The "Directory" button sets the default location for the report files that are created using this feature. The actual name of the report file is based on the host name. I replace all of the "." in the host name with a "_" and then tag on the end ".rpt". This file is then saved using the directory specified by this button. The Add, Del and Save buttons are used to manage the NETWORK.DAT file. This file holds the information needed for the feature to work. This file must be located in the same directory as the WQ exe file. You also need the REPORT.DAT file. This file has the parsing information use to extract the event information. It also needs to be in the same dir. as the WQ exe file. Both DAT files are in the beta zip file. In the future WinQuake will be able to get other information using direct connection to the Internet. This could be event files or other report information that is not available as a finger service. I would like to get the norcal.list file directly using http. This file has all of the local events, even the ones smaller then the 2.0 cutoff of the quake@.............. list. This list is available using http and maybe ftp. What I need to do is figure out the protocol of both so I can have WQ use these protocols to download data/files. The second new feature is only for SDR users. It is supported in both the 16 and 32 bit versions. This feature allows the user to request/replay an event file using WinQuake. To use this feature you must have your SDR and main Windows system (Win3.1, Win95 or NT) networked together using two NIC cards. Many of the sdr users have there systems networked so I thought I would add this feature. It uses the same SDR feature used to implement the request data form at http://psn.quake.net/request.html. This form allows the user to extract a PSN formatted event file from my SDR systems based on a start time, number of minutes to save, channel etc. SDR then uses this info and creates an event file. Its similar to doing a replay, but remotely. Setting things up to get this feature working is a little complicated so here it goes... First you need to get the two systems networked together. I would suggest loading Win95 on both systems if you are going to try doing this. In the beta release of SDR there is a netwin95.txt file that explains how to do this. Another file you need too read is sdrwin95.txt. This file explains how to run SDR in the DOS only mode of Win95. If you get the network stuff working you should be able to map a drive letter, say "D:" on your SDR system so that it is the same drive as the "C:" (or other local disk) drive on your Windows system. Another words, if you have a dir/path called c:\sdr\event\ on your Windows system, and, if you have your sdr system maps the D: drive to be the same as the C: drive on the other system, then, d:\sdr\event\ will be the same directory, and, files can be shared between the two systems. For this feature to work you will need two directories. One will hold the temporary request information file that SDR reads for the replay information, and the other will hold the returned event file. Create two directories like c:\sdr\event and c:\sdr\request on your Windows system. Now enter the shared drive and path information in the field "Request Control File Path" under the F5 settings in SDR. If the SDR D: drive = the C: drive on the Windows system then enter "d:\sdr\request\" for that menu item. That's all you need to do the SDR side of things. SDR will look for a request file in that dir. every 10 seconds. If it finds one, it tries to do the replay and create the event file. For more information on how the request process works in SDR, please read the request.txt file that comes with the beta release of SDR. Now for WinQuake. When WQ firsts starts up it looks for a file called REPLAY.DAT in the same dir. as WQ runs out of. If it finds it, then the new "Replay" button in the File Open dialog box will be enabled. If the file is not there this button will be disabled. Since this button will be disabled when you run the new WQ for the same time you will have to use the menu item called "Replay Setup" under the File menu items. This dialog box is used to create and manage the REPLAY.DAT file. The first item in this dialog box is the returned event file path that SDR will use to place files in. Use the "Change" button to select the directory that you will be using, like c:\src\event, to hold the returned event files in. Next you need to add the channel information for each of your sensors you are running. For each channel select the "Add" button. In the Add Replay info dialog box add the File extension for that channel, like LC1. If you only have one sdr system keep the SDR system number at 1. For the Control File directory use the "Change" button and select the dir. you will be using for the request control file, like c:\sdr\request. After entering the replay info you should be able to do a replay. The Replay button should now be enabled in the File Open dialog box. In the Replay dialog box you will see a series of edit boxes for the start time, save length, channel etc. After filling in the start time and channel press the "Replay" button. WQ will create a request file for SDR to read and then waits for the event file to be created by SDR. If after ~40 seconds there is no event file found, WQ will time out. If it does find the event file it will close out the Replay dialog box and open the event file. The "Report" and "Report Time" can be used to set the starting time based on the currently selected report time. The Save Default check box is used to save selected fields, marked with a * in the group box name, as default settings for the next time you run WQ. The SDR beta release as only minor changes in it. While you do not need to upgrade to it for the second WQ feature to work, it would be best if you do. This version as some changes around how SDR handles request file errors. Thats it! The beta release for both the 16 and 32 bit version of WinQuake and SDR can be download using the following URL's. 32 bit WinQuake: ftp://ftp.seismicnet.com/users/psn/software/wq32b1.zip or ftp://psn.quake.net/software/wq32b1.zip 16 bit WinQuake: ftp://ftp.seismicnet.com/users/psn/software/wq16b1.zip or ftp://psn.quake.net/software/wq16b1.zip SDR: ftp://ftp.seismicnet.com/users/psn/software/sdr24b.zip or ftp://psn.quake.net/software/sdr24b.zip Please use the ftp.seismicnet.com address if possible. This system is on a higher speed link into the Internet then my 28.8k modem at psn.quake.net. The WinQuake zip files only contain the new exe and some dat files. After unzipping the file all you need to do is copy the files over to your working WinQuake directory. Make sure you stop the old version before doing the copy. For the SDR release there is a new exe file and all of the current text files I have for documentation. All you need to do is copy the sdr.exe file over to your SDR system and restart it. If you run into any problems, of have suggestions on the new features (or old ones) please let me know. Thats it, enjoy! -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Fontana, CA Trend 4.0 Date: Wed, 15 Oct 1997 01:06:09 -0700 (PDT) Hi All! There was a 4.0 in Fontana, CA that occurred at 3:31 PM PDT. Maybe the erratic readings on my equipment that I noted here just a few days ago was a precursor to it. I monitor the range of 0.1 to 3.0 Hz for any changes in signal amplitude and noticed quite an erratic amplitude shift in the last week before the 4.0. The monitoring location is within five miles of the epicenter. I figured that I was seeing some kind of event brewing on the San Jacinto Fault. I was monitoring and noting some drastic changes in the geo-magnetic field strength of the area, too. I noted my last drastic change in signal level at approximately 3 PM PDT, only 30 minutes before the earthquake happened. Did anyone else in this area get any strange readings prior to this event? I'd be interested in sharing notes with you if possible. Oh, and BTW what ever happened to the predicted Parkfield event? Send mail to: frankcnd@.......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: 3D displays and holograms etc. Date: Wed, 15 Oct 1997 11:56:39 +0100 Dr. John Lahr (USGS-GI Seismologist) wrote: > Albert, > > Another way to get the in-and-out direction would be with > 3D colored glasses. Each ball would be drawn twice, once > in red and once in blue. Use zero seperation for the circles > when the ball is in the plane of the screen and increase the > separation linearly one way for into the screen locations and > the other way for out of the screen location. Viewed with 3D > glasses the ball will appear to move in and out of the screen > as well as laterally. > > I wrote a program in the DOS-Turbo Pascall-days that would > display a rotating wire frame figure this way and it worked > well. > > JCLahr Hello John, Thanks for your comments re 3D moving earth partical display. (I think I must shorten this to MEP .) Yes, your red and blue balls + glasses, would be VERY impressive. I have great concern over here, that youngsters are not being exposed to enough science. You may know that our Prof. Richard Dawkins (author of, ' The selfish gene etc.) , now holds a chair at Oxford, solely to promote the advancement of science, among the general population. Now, seismic drum recordings , and PC analysis are fine for those in the know, but it doesn't SHOW youngsters, (or me!!), what is really going on, 'down there', as if we were really PRESENT in the bowels of the earth, does it? As a professional seismologist, you are no doubt be more aware of this, than I. I can visualise, in a science or geological museum, this 3D display, showing EXACTLY how the earth particals move during an earthquake......it may not be scientific, but it would encourage more to take an interest in what is beneath their feet . What do you think about this? Earthquakes from the past could be easily 'replayed', at x2, x10 ,x100, etc. speeds, as well as in real time, to demonstrate how the P, S, Love and Rayleigh waves etc. arrive. Near events would certainly be of interest, the 'earth partical ball', oscillating as it would, with a bias towards the 'event' direction. Any pile driving, or underground trains passing in town would look very good as well , don't you think? "Oh yes,", says a visitor to the museum, "there's a train passing from east to west, and there's the vibration from the new store going up on 52nd. street".....!!!!! Perhaps a hologram of the moving ball earth partical in the centre of an area, where one could walk AROUND IT, etc, would be the ultimate display....as I mentioned in my e-mail to Jim, this hologram display is certainly my aim................... .........DOES ANYONE OUT THERE USE PC CONTROLLED HOLOGRAMS, which could be adapted to show 3D moving earth partical displays, (MEP's ), using the o/p from 2 horizontal and one vertical seismograph??? Thanks for reply John...I would like to take this opportunity to thank all who have responded to my letters. It's a great help getting this knowledgable feedback, here in my village, where seismographic information is somewhat sparse!! Regards to you John, and all, Albert Noble (England). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: lahr@................. (Dr. John Lahr (USGS-GI Seismologist)) Subject: Re: Seismograghs and software. Date: Wed, 15 Oct 1997 10:55:21 -0800 > From dann@........ Tue Oct 14 15:49:35 1997 > > John, > just been playing with the phase arrival time setup on your pages > interesting.... there must be some differences in you calc. methods to > what Larry uses in Winquake. > > eg. here is the data from your calc. > > DATE-(UTC)-TIME LAT LON DEPTH MAG Q COMMENTS > 97/10/14 09:53:18 21.95S 176.92W 166.2 6.5Mb A FIJI ISLANDS REGION > > delta azimuth (degrees clockwise from north) > (deg) eq-to-station station-to-eq > 25.92 200.4 27.6 > > travel arrival time > # code time(s) dy hr mn sec > 1 P 316.61 0 9 58 34 > 2 P 320.80 0 9 58 38 > 3 S 575.14 0 10 2 53 > 4 PKiKP 980.06 0 10 9 38 > > Questions there are two "P" times ? > you have delta deg and station to eq deg what is > the difference ? > > Now the distance calc. by WQ for the distance between me and the epic. is > is 2886 km or 25.95 deg (which is your delta deg. measurement). > > TNX > Dave Dave, The eq-to-station and station-to-eq numbers refer to the azimuth from the earthquake to the station and visa versa. The difference between 25.95 and 25.92 must be in the distance algorithms used. The travel time software I'm using is from NEIC and it reports phases whenever there is an arrival, according to the crustal model, rather than just the first arrival of a type. The two P phases are for rays that "bottom out" at different depths. JCLahr ################################## John C. Lahr ################################# Seismologist ################################ U.S. Geological Survey ############################### c/o Geophysical Institute ############################## 903 Koyukuk Drive ~~~~~~~~~~~~~~ Get ~~~~~~~~~~ ############################# ########################################################### P.O. Box 757320 ################################ Fairbanks, AK 99775 ################################# Phone: (907) 474-7997 ################################## Fax: (907) 474-5618 ~~~~~~~~ the thrust? ~~~~~~~~~~~~~~ lahr@........ #################################### http://www.aeic.alaska.edu/Input/lahr/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Martin Brewer Subject: RE: New Station on the USA map Date: Wed, 15 Oct 1997 17:38:38 -0300 Welcome Robert and hello again everyone else. Robert, did you or anyone else pick up one or more 'quakes with an = origin time around 10:08 UTC on 14 October? I recorded a very rich = trace about that time (peak amplitude 939) which appears to be a = magnitude Ms 6.6 at a distance of about 35 degrees (3,800 km) from = Bermuda. The only event I see listed by NEIC around that time is the = one in the Fiji Islands region with origin time 09:53:18 and magnitude = Mb 6.5 But it can't be that one as the event was 119 degrees from = Bermuda. It could be a series of much smaller local events in the North = Atlantic? Be glad of any feedback, Martin -----Original Message----- Hi all, Please welcome Robert Laney from Herndon, Va, to the group. = =20 It's good to see another east coast seismic station up and running, = look for him on the USA map on my pages. Dave From: Edward Cranswick Subject: Itailian M5 Tuesdy 14 Oct Earthquake: Reports/Recordings? Date: Wed, 15 Oct 1997 15:31:06 -0600 PSN- I am sitting here with Paolo De Martini who has asked me whether there is anyt PSN information about the M5 earthquake that took place yesterday in the same location as the earthquakes of 26 Sep. Paolo is a paleoseismologist working at the National Istitute of Geophisics in Rome and he is interested in this last aftershock that is not so small considering the elapsed time with respect the main one! -Paolo Marco De Martini -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Three Dimensional Seismograph, thoughts, and a poem! Date: Wed, 15 Oct 1997 20:48:12 -0400 Prewar, Re:heaters for seismometer enclosures. I described my enclosure-heater= system for a Lehman rather fully in e-mail to the list on 10/29/96. You can look at this by going to psn.quake.net, then to "Archives of Past PSN-L messages". Then download the 4th quarter of '96 (psnl96q4.zip, 114k). After unzipping, search for "styrafoam". Yes, I'm sure that the heater should be placed at the center of the top= of the enclosure. This will stagnate the air in the box and prevent convection currents. My heater is a 5 ohm resistor supplied with 9V AC a= nd thus dissapates 16 watts. This produces a gradient of about 8 deg F from= top to bottom (hotter at the top, of course). Of course, the size of the= gradient with 16 watts will depend upon the quality of the insulation. T= he 2" thick styrafoam I have is highly insulating. This thing is in my basement where the temp. over the whole year is in the range from 60 to 7= 5 deg F. I'm guessing that even in a less stable place, this much insulati= on will give good performance. I now have an additional 1 year of experience with this arrangement and= I'm still very happy with it. You can make a thermometer for probing the inside of the box from eithe= r a Si diode or a Si transistor. For the transistor, make it into a diode = by shorting the base to the collector. If these are small( e.g. 2N2222), th= ey will have fast response. With either of these, measure the forward volta= ge drop across the device in series with a relatively high resistor. I used= 22,000 ohms in series with a 9V battery. Use a digital voltmeter. The forward voltage drop is very linear with temperature and the slope is -2.= 2 millivolts/deg C. Of course, you will have to calibrate each unit by measuring the voltage at a known temperature. = = Best of luck with your rig. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Surface wave amplitude Date: Wed, 15 Oct 1997 07:25:27 -0700 Hi All I have been getting teleseismic events with small P & S amplitudes and large surface amplitudes. Recently I have been getting the opposite ie. large P & S amplitudes and little or no surface waves. I suspect it has to do with the depth of the event and the direction of the station orentation with respect to the orentation of the event. Any thoughts?? Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Surface wave amplitude Date: Thu, 16 Oct 1997 15:16:51 +1200 Barry, yes, depth and orientation do both have an effect on the resulting seismogram. it is also interesting to note that NOT all large shallow events are rich in surface waves, some do, some don't, on the other hand over the many years I have seen several moderate events (5.5 - 6.3) that have very strong surface waves. one in particular was in the late '80's, a Mb6.2 in the Bay of Plenty, Nth Is. NZ, the P and S amplitudes were "normal" for that sized event at its distance from me but the surface waves went on and on and on. Talking to the Seis. Obs. professionals at the time, they suggested that it was a very shallow event and a very long fault rupture. A feature I also notice here in Dunedin, NZ, is that quakes over 2500km ( ie. the Santa Cruz. Is., Fiji, Tonga regions) usually have a much larger P wave ampl. than the S wave. on a horizontal seismometer. there may/may not be some surface waves depending on the quake depth. Dave At 07:25 AM 10/15/97 -0700, you wrote: >Hi All > I have been getting teleseismic events with small P & S amplitudes >and large surface amplitudes. Recently I have been getting the opposite >ie. large P & S amplitudes and little or no surface waves. I suspect it >has to do with the depth of the event and the direction of the station >orentation with respect to the orentation of the event. Any thoughts?? > Barry Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Ryan A. Meyer" Subject: novice to this hobby Date: Fri, 17 Oct 1997 01:19:09 -0400 X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Tjis is very interesting stuff!! I am presently building the mechanic part of a Lehman seismograph...using the plans that were published years ago...Is there a better electronic amp to build than the one shown in the magizine? More gain and/or less noise? I'm certain that over the years and with all the electronic wizards out there, there's no sense in trying to re-invent the wheel.... Any comments will be appreciated, please e-mail them to me at: dmeyer@.............. thanks!! JIM WT2W _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: seisvole and seismic waves Date: Thu, 16 Oct 1997 17:45:15 +0100 Dr. John Lahr (USGS-GI Seismologist) wrote: > Albert, > > Check out these two programs, which I think are excellent for > education. You may have seen this posting, but I'm not sure when > you joined the psn listserver. > JCLahr > > > From lahr@................. Sat Oct 4 11:24:22 1997 > > Date: Sat, 4 Oct 1997 11:33:48 -0800 > > From: lahr@................. (Dr. John Lahr (USGS-GI Seismologist)) > > To: psn-l@.............. > > Subject: Re: Image maps - seisvole - seismic > > Cc: lahr@................. > > > > > There are far too many features to describe in detail here. For > > more information on Seismic, check out Alan Jones' home page at: > > http://sunquakes.geol.binghamton.edu/faculty/jones/ > > > > http://www.aeic.alaska.edu/Input/lahr/ > > Hello John, Thanks...have started looking at these web pages, very good and most helpful to me.........somewhat more up to date than the seismo books which I have. What with these, and the archives, I shall be burning the midnight oil for many nights to come!! Regards, Albert Noble (England) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: Seismograghs and software. Date: Thu, 16 Oct 1997 15:37:03 -0700 At 10:55 AM 10/15/97 -0800, John Lahr wrote: >Dave, > >The eq-to-station and station-to-eq numbers refer to the azimuth from >the earthquake to the station and visa versa. The difference between >25.95 and 25.92 must be in the distance algorithms used. That works out to be about 3km difference... 1 deg = ~111.17km so 111.17 * ..03 = 3.33km -Larry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Martin Brewer Subject: Fiji event - Bermuda Date: Thu, 16 Oct 1997 20:44:22 -0300 Dave, I tried to send you two files(N-s and E-W) of the event I recorded at = the time the Fiji region 'quake occurred. I tried to send it by e-mail = from your home page but I got a message from the internet server = administrator that it couldn't be sent. As you know my C-drive got = wiped out recently. Please send me your e-mail address that I can use = from here. I apologise to all the other users for cluttering up the list with this = private message. Martin From: James Subject: From the "Drudge Report" Date: Thu, 16 Oct 1997 22:33:54 -0500 (CDT) Hello, I just had to pass this on. Found this in the Drudge Report http://www.drudgereport.com/ FRIDAY ENDING... Seismologists remain baffled by the continuing tremors in Italy. More than 2,000 events, six of them measuring more than four on the Richter scale, have hit central Italy over the past 20 days. Many DRUDGE REPORT readers in Italy have e-mailed in with dramatic details of life during the swarms. But now the LONDON TIMES runs a report in Friday editions that takes it all the way: rumors are spreading throughout Italy that "the Big One" is set to strike within the next 24 hours, in accordance with the prophecies of Nostradamus. The TIMES' Rich Owen filing from Rome: "For many superstitious and increasingly nervous Italians, the quakes reveal 'the hand of God' or at least of fate. 'An earthquake obsession without end' was the headline in yesterday's LA STAMPA, which reported that people near the epicenter were 'awaiting the end of the world...' "Bookshops in Rome and Perugia have sold out of the prophecies of Nostradamus, who is said to have predicted that the end of the world would be presaged by quakes "on three Fridays in a row". Many Italians believe Nostradamus predicted a third, apocalyptic earthquake today. Psychologists said pre-millennial fears were becoming widespread." _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: Surface wave amplitude Date: Thu, 16 Oct 1997 19:48:26 -0700 The 6.8Ms Chile event a few days ago was a strange one... It is listed as a shallow event (33km deep) but it produced very small surface wave amplitudes. The P and S where very large compared to the surface waves. Before the NEIC reported it I thought it was a deep event. Oh well..... -Larry Cochrane Redwood City, PSN At 03:16 PM 10/16/97 +1200, Dave Nelson wrote: >Barry, > yes, depth and orientation do both have an effect on the >resulting seismogram. it is also interesting to note that NOT all large >shallow events are rich in surface waves, some do, some don't, on the >other hand over the many years I have seen several moderate events (5.5 - >6.3) that have very strong surface waves. one in particular was in the >late '80's, a Mb6.2 in the Bay of Plenty, Nth Is. NZ, the P and S >amplitudes were "normal" for that sized event at its distance from me but >the surface waves went on and on and on. > Talking to the Seis. Obs. professionals at the time, they suggested that >it was a very shallow event and a very long fault rupture. > > A feature I also notice here in Dunedin, NZ, is that quakes over 2500km >( ie. the Santa Cruz. Is., Fiji, Tonga regions) usually have a much larger >P wave ampl. than the S wave. on a horizontal seismometer. there may/may >not be some surface waves depending on the quake depth. >Dave _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Temperature control Date: Fri, 17 Oct 1997 09:59:11 -0400 Hi gang, There has been a lot of discussion recently about accurate temperature control of seismometer housings. I have no experimental evidence to cite on this question, just some thoughts based on general principals. If anyone has some directly applicable experience, I'm sure that we all would all like to here about it. At least for Lehman-type seismometers (used as velocity transducers in the usual fashion), I see no need for temperature control if the housing = is a good thermal insulator and a temperature gradient is established with t= he air at the top being a few degrees hotter than the bottom. This temperature gradient should greatly reduce convection currents in the air= around the seismometer. If the air temperature outside the housing chang= es so fast that the gradient is upset, air currents inside would give spurio= us signals but this seems very unlikely if ths insulation is good. I think that using a lamp at its rated voltage for the heat source is a= poor choice since the heat radiated by the lamp may heat different parts = of the sensor by different amounts. As the lamp is cycled on and off, this could introduce motion in the boom due to differential expansion of parts= of a Lehman (or an S-G). Heat transfer from resistors (which work at muc= h lower temperaure than a lamp filiament) will be predominantly by convecti= on and should cause much less differential expansion in parts of the Lehman.= A Lehman in its usual velocity sensitive mode is an AC device, that is,= its response does not extend to zero frequency. I think that this sez th= at its performance will be the same at 0 deg. and 100 deg. F. It seems possible that differential expansion of parts of a Lehman in this sort of= temperature range might change its period and/or the rest position of the= boom but I doubt that these changes would be significant. = Since a Shackleford-Gunderson operates part of the circuitry at DC, it might not be as immune to wide temperature swings. Maybe Larry can give = us his thoughts on this. Bob Barns = = _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: GeE777@....... Subject: Southern California Quakes Date: Fri, 17 Oct 1997 11:23:16 -0400 (EDT) During the last week, there have been many more than the normal numbers of events with less than 4.0 MAG. in Southern California. Is there a message here? George Erich GeE777@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: Southern California Quakes Date: Fri, 17 Oct 1997 08:38:53 -0700 One intesting thing is that there were three Southern California quakes in the 2's that all occurred within 2 minutes after the arrival of the P waves from the recent Fiji event. Hmmmmm. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Greg Lyzenga Subject: Re: Temperature control Date: Fri, 17 Oct 1997 08:55:57 -0700 >Hi gang, > There has been a lot of discussion recently about accurate temperature >control of seismometer housings. > I have no experimental evidence to cite on this question, just some >thoughts based on general principals. If anyone has some directly >applicable experience, I'm sure that we all would all like to here about >it. > At least for Lehman-type seismometers (used as velocity transducers in >the usual fashion), I see no need for temperature control if the housing is >a good thermal insulator and a temperature gradient is established with the >air at the top being a few degrees hotter than the bottom. ....(text deleted) >Bob Barns > I have similar opinions based on my experience. After a lot of only semi-successful experiments with heating the enclosure of my Lehman, I accidentally stumbled on what has turned out to be the most effective solution. In my experience, the most important factor has turned out to be brute force insulation. Lots of it. I had lined my box with the 2-inch variety of foil-backed foam building insulation, and it worked reasonably well with a little resistive top heating (~12 watts), although I still experienced some periods of convection during cold weather. Then I stumbled onto an improvement. It just so happened that our insulated spa cover was so badly weathered that it had to be replaced. However, being an incurable packrat, I couldn't bear to throw away two big sheets of 4-inch thick styrofoam, so I stashed them away in the garage. The only place I could find for them that was out of the way was wedged in the corner between the garage wall and my Lehman enclosure. Right away my thermal noise problems practically vanished! That extra few inches of foam did a lot more than I would have expected. So for me the moral of the story is insulate, insulate, insulate! - Greg _____ Gregory A. Lyzenga, Dept. of Physics, Harvey Mudd College lyzenga@................. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: lahr@................. (Dr. John Lahr (USGS-GI Seismologist)) Subject: Re: Surface wave amplitude of Chile Earthquake Date: Fri, 17 Oct 1997 08:40:38 -0800 Larry, Stu Sipkin's moment tensor solution for the Chile M6.8 quake of October 15 found a depth of 67 km. finger quake@................. still shows 33 km for the M6.8 but 47 km and 63 km for M5.4 aftershocks. Chances are the final solution for the main shock will have a depth in the 60's. JCLahr ***** Larry wrote: The 6.8Ms Chile event a few days ago was a strange one... It is listed as a shallow event (33km deep) but it produced very small surface wave amplitudes. The P and S where very large compared to the surface waves. Before the NEIC reported it I thought it was a deep event. Oh well..... -Larry Cochrane Redwood City, PSN ################################## John C. Lahr ################################# Seismologist ################################ U.S. Geological Survey ############################### c/o Geophysical Institute ############################## 903 Koyukuk Drive ~~~~~~~~~~~~~~ Get ~~~~~~~~~~ ############################# ########################################################### P.O. Box 757320 ################################ Fairbanks, AK 99775 ################################# Phone: (907) 474-7997 ################################## Fax: (907) 474-5618 ~~~~~~~~ the thrust? ~~~~~~~~~~~~~~ lahr@........ #################################### http://www.aeic.alaska.edu/Input/lahr/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: [Fwd: Re: From Italy] Date: Fri, 17 Oct 1997 11:44:23 -0600 -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". Giovanni- That is a beautiful record. You should upload it to the PSN. The record appears to have less low-frequency content than it should from a seismometer with a period of 9 seconds. Paolo is now back in Rome, and I hope we, i.e., PSN, hear from him. -Edward Giovanni Rotta wrote: > > Hi Edward ! > I send you the file of the M5 earthquake of 14 October in Central Italy. > Have my best regards and a special greeting to Paolo from Italy. > Giovanni > > Giovanni Rotta > rottag@.......... > Via F. Pizzigoni, 10 > 33010 Resia (Udine) Italy > Lat. 46.22N Long. 13.18E > > --------------------------------------------------------------- > > Name: 971014l.gr1 > Type: unspecified type > Part 1.2 (application/octet-stream) > Encoding: base64 > Description: 971014l (GR1 File) -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". From: "Walter Williams" Subject: Chatsworth Quake Date: Fri, 17 Oct 1997 12:42:48 +0000 Hello All, Yesterday, (Oct. 16, 1997) around 09:00 (AM) PDT in the Chatsworth California, USA area (about 25 miles NW of Los Angeles), a 3.0m aftershock of the 1994 Northridge event was reported by local area news sources. My home is located in a neighbor area of Chatsworth. I was surprised when I did not see any posted comments in the PSN-L list both yesterday and today regarding this event? I fully expect the USGS instruments to sense these small events. But how many of the home-brew instruments created and maintained by members of the PSN were able to sense this event and how far away? Thank you. Best Regards Walt Williams, 97.10.17 dfheli@.............. Woodland Hills, California USA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Greg Lyzenga Subject: Re: Chatsworth Quake Date: Fri, 17 Oct 1997 13:06:52 -0700 >Hello All, > >Yesterday, (Oct. 16, 1997) around 09:00 (AM) PDT in the Chatsworth >California, USA area (about 25 miles NW of Los Angeles), a 3.0m >aftershock of the 1994 Northridge event was reported by local area >news sources. My home is located in a neighbor area of Chatsworth. I >was surprised when I did not see any posted comments in the PSN-L >list both yesterday and today regarding this event? I fully expect >the USGS instruments to sense these small events. But how many of >the home-brew instruments created and maintained by members of the >PSN were able to sense this event and how far away? > I picked up the Chatsworth event just fine in Altadena, although it was not an especially remarkable event, particularly in light of some of the other bigger local events and teleseisms that have been coming in over the last few days. - Greg _____ Gregory A. Lyzenga, Dept. of Physics, Harvey Mudd College lyzenga@................. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Walter Williams" Subject: Re: Chatsworth Quake Date: Fri, 17 Oct 1997 15:27:30 +0000 Hello All, Actually the intent of my question was probably not too clear. Since this event was fairly small, I wondered at what large distance a small seismic event could be sensed using home-brew instruments in difference to 'professional' instruments. Could our friends in Italy sense a 3.0m event in Chatsworth should they happen to be using home-brew instruments? I infer the premise of this group is biased along amateur equipment usage. Thank you. Walt Williams, 97.10.17 dfheli@.............. Woodland Hills, California USA ------- Forwarded Message Follows ------- Date: Fri, 17 Oct 1997 13:06:52 -0700 From: Greg Lyzenga Subject: Re: Chatsworth Quake To: PSN-L Mailing List Reply-to: PSN-L Mailing List >Hello All, > >Yesterday, (Oct. 16, 1997) around 09:00 (AM) PDT in the Chatsworth >California, USA area (about 25 miles NW of Los Angeles), a 3.0m >aftershock of the 1994 Northridge event was reported by local area >news sources. My home is located in a neighbor area of Chatsworth. I >was surprised when I did not see any posted comments in the PSN-L >list both yesterday and today regarding this event? I fully expect >the USGS instruments to sense these small events. But how many of >the home-brew instruments created and maintained by members of the >PSN were able to sense this event and how far away? > I picked up the Chatsworth event just fine in Altadena, although it was not an especially remarkable event, particularly in light of some of the other bigger local events and teleseisms that have been coming in over the last few days. - Greg _____ Gregory A. Lyzenga, Dept. of Physics, Harvey Mudd College lyzenga@................. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Southern California Quakes Date: Fri, 17 Oct 1997 17:24:47 -0700 (PDT) Hi George: The message is that we had better get our acts together, cause mother Earth is making some adjustments in the environment. Look at the swarm of small tremors in th Mammoth Lakes area over the last few weeks. Also, many weather changes are occurring with El Nino on the horizon! Another interesting fact is that there was a full blown Santa Ana wind condition during the time of the latest 4.0 magnitude earthquake and the temperatures were raised by about 20 degrees. Frank... >During the last week, there have been many more than the normal numbers of >events with less than 4.0 MAG. in Southern California. Is there a message >here? > >George Erich >GeE777@....... > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: Chatsworth Quake Date: Fri, 17 Oct 1997 20:52:15 -0600 Walter- In general, the detection threshhold for earthquakes is as much a function of the noise characteristics of the station site as the response characteristics of the instrumentation. If you want to detect very small earthquakes whose dominant frequencies are >10 Hz , you want your sensor to be downhole to escape both surface noise sources and the severe low-pass filtering effects of the near-surface. Sensor location variation can produce an order-of-magnitude in signal/noise ratio, and the differences between professional and amateur equipment will usually not be so great in the frequency band 0.1 - 10.0 Hz. -Edward Walter Williams wrote: > > Hello All, > > Actually the intent of my question was probably not too clear. Since > this event was fairly small, I wondered at what large distance a > small seismic event could be sensed using home-brew instruments in > difference to 'professional' instruments. > Could our friends in Italy sense a 3.0m event in Chatsworth should > they happen to be using home-brew instruments? I infer the premise > of this group is biased along amateur equipment usage. > > Thank you. > > Walt Williams, 97.10.17 > dfheli@.............. > > Woodland Hills, California > USA > > ------- Forwarded Message Follows ------- > Date: Fri, 17 Oct 1997 13:06:52 -0700 > From: Greg Lyzenga > Subject: Re: Chatsworth Quake > To: PSN-L Mailing List > Reply-to: PSN-L Mailing List > > >Hello All, > > > >Yesterday, (Oct. 16, 1997) around 09:00 (AM) PDT in the Chatsworth > >California, USA area (about 25 miles NW of Los Angeles), a 3.0m > >aftershock of the 1994 Northridge event was reported by local area > >news sources. My home is located in a neighbor area of Chatsworth. I > >was surprised when I did not see any posted comments in the PSN-L > >list both yesterday and today regarding this event? I fully expect > >the USGS instruments to sense these small events. But how many of > >the home-brew instruments created and maintained by members of the > >PSN were able to sense this event and how far away? > > > > I picked up the Chatsworth event just fine in Altadena, although it > was not an especially remarkable event, particularly in light of some > of the other bigger local events and teleseisms that have been coming > in over the last few days. > > - Greg > > _____ > Gregory A. Lyzenga, Dept. of Physics, Harvey Mudd College > lyzenga@................. > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: shammon1@............. Subject: Re: Chatsworth Quake Date: Fri, 17 Oct 1997 21:56:11 -0700 Walter, I currently have the gain down on my Lehman in San Jose and 3.5 is too distant to record at 420KM whoever, I had it set at a gain of 2100 following the the Northridge quake and recorded all the 4.2 and larger events. Regards, Steve Hammond PSN San Jose Walter Williams wrote: > > Hello All, > > Actually the intent of my question was probably not too clear. Since > this event was fairly small, I wondered at what large distance a > small seismic event could be sensed using home-brew instruments in > difference to 'professional' instruments. > Could our friends in Italy sense a 3.0m event in Chatsworth should > they happen to be using home-brew instruments? I infer the premise > of this group is biased along amateur equipment usage. > > Thank you. > > Walt Williams, 97.10.17 > dfheli@.............. > > Woodland Hills, California > USA > > ------- Forwarded Message Follows ------- > Date: Fri, 17 Oct 1997 13:06:52 -0700 > From: Greg Lyzenga > Subject: Re: Chatsworth Quake > To: PSN-L Mailing List > Reply-to: PSN-L Mailing List > > >Hello All, > > > >Yesterday, (Oct. 16, 1997) around 09:00 (AM) PDT in the Chatsworth > >California, USA area (about 25 miles NW of Los Angeles), a 3.0m > >aftershock of the 1994 Northridge event was reported by local area > >news sources. My home is located in a neighbor area of Chatsworth. I > >was surprised when I did not see any posted comments in the PSN-L > >list both yesterday and today regarding this event? I fully expect > >the USGS instruments to sense these small events. But how many of > >the home-brew instruments created and maintained by members of the > >PSN were able to sense this event and how far away? > > > > I picked up the Chatsworth event just fine in Altadena, although it > was not an especially remarkable event, particularly in light of some > of the other bigger local events and teleseisms that have been coming > in over the last few days. > > - Greg > > _____ > Gregory A. Lyzenga, Dept. of Physics, Harvey Mudd College > lyzenga@................. > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: Chatsworth Quake Date: Fri, 17 Oct 1997 23:16:54 -0600 Walter- I got carried away with my answer to your first question and forgot the second one (below), but reading Steve Hammond's response jogged my consciousness. Walter Williams wrote: > Could our friends in Italy sense a 3.0m event in Chatsworth should > they happen to be using home-brew instruments? I infer the premise > of this group is biased along amateur equipment usage. At one of the best sites in the world, i.e., with the quietest noise characteristics and best coupled to hardrock basement, the Soviets were able to record a magnitude 3.9 ML nuclear explosion detonated at the US Nevada Test Site (NTS) at their secret seismograph station at Borovoye in Kazakhstan. -Edward -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Chatsworth Quake Date: Sat, 18 Oct 1997 19:51:19 +1200 Ed, what sort of depth is applicable, 2, 5 , 10 or more metres to see a signigicant improvement. Dave At 08:52 PM 10/17/97 -0600, you wrote: > If you want to detect >very small earthquakes whose dominant frequencies are >10 Hz , you want >your sensor to be downhole to escape both surface noise sources and the >severe low-pass filtering effects of the near-surface. >-Edward Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: GeE777@....... Subject: Re: Chatsworth Quake Date: Sat, 18 Oct 1997 10:29:26 -0400 (EDT) In a message dated 97-10-18 03:54:49 EDT, dann@........ writes: << what sort of depth is applicable, 2, 5 , 10 or more metres to see a signigicant improvement. >> Even though I am new with PSN, I may be able to help you. I have a background wirh seismic exploration Burying our geophones just below the surface should increase the signal to noise ratio by 6db. In normal sedimentary dry soil, the seismic velocity is about 2000 feet per second. When one gets to the water table, the velocity increases to about 6000 f/s. We find to get the geophone in the water table gives us better coupling and reduces the S/N ratio. I want you to know we deal with frequencies that are usually higher than 10 Hz George Erich GeE777@....... Norwalk, California USA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Chatsworth Quake Date: Sun, 19 Oct 1997 02:59:00 +1200 Ok George, thanks for the comments, at the moment my three 4.5 Hz geophones are maybe about 12" deep they are encased in a sealed plastic tube so could easily handle going a bit deeper. I have only ~6 - 10" of soil before a thick layer (up to 30 ft) of very hard clay below that are sandstones and limestones. what do you call just.....? when you are refering to phones in the water table you are infering that they are surrounded by wet ground ?? how does that give better coupling ?? from my above comments you could imaging that I would have a hard time finding an accessable watertable depth at my location Now speaking of response My offsider Malcolm, in Christchurch city to the north of me, (which is basically built on a swamp) and I have noticed an interesting response of his 4.5 Hz phone. it is ~6" below surface E/W orient. surrounded by sand and the water table is only a couple of feet further down. We have noticed that his system responds much better to the events ~1000km and greater than the more regional events ( say 100-300km). Which is opposite to the response that I see with the very hard ground that I am on. Interested in your comments TNX Dave > >Even though I am new with PSN, I may be able to help you. I have a background >wirh seismic exploration Burying our geophones just below the surface >should increase the signal to noise ratio by 6db. In normal sedimentary dry >soil, the seismic velocity is about 2000 feet per second. When one gets to >the water table, the velocity increases to about 6000 f/s. We find to get >the geophone in the water table gives us better coupling and reduces the S/N >ratio. I want you to know we deal with frequencies that are usually higher >than 10 Hz > >George Erich >GeE777@....... >Norwalk, California USA > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: Chatsworth Quake Date: Sat, 18 Oct 1997 11:29:52 -0700 (MST) On Sun, 19 Oct 1997, David A. Nelson wrote: > thanks for the comments, at the moment my three 4.5 Hz > geophones are maybe about 12" deep they are encased in a sealed plastic > tube so could easily handle going a bit deeper. I have only ~6 - 10" of > soil before a thick layer (up to 30 ft) of very hard clay below that are > sandstones and limestones. Dave, if I were you I would try to unearth a flat portion of that hard rock and cement the tube to it or anchor it somehow. SS and LS rock would probably transmit the waves a whole lot better that anything above it... I wish I had hard rock around here!!! ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Palmdale Bulge Date: Sat, 18 Oct 1997 14:04:14 -0700 (PDT) Greetings All: Yesterday, there was an earthquake (small one) listed as being on the San Andreas fault near Palmdale, CA . Isn't it unusual to have an earthquake (even small ones) on a section of the fault that is supposedly locked? Check out the item in qustion here! http://quake.wr.usgs.gov/recenteqs/Quakes/sc9026859.html Please let me know what your thoughts are about this one. Thanks, Frank... email to: frankcnd@.......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: sensor burial Date: Sun, 19 Oct 1997 09:32:24 +1200 John, unfortunately wont find accessable rocks on my property, other than what is in my collection. anyway how's your system going haven't heard from you for a while dave At 11:29 AM 10/18/97 -0700, you wrote: > Dave, if I were you I would try to unearth a flat portion of that hard >rock and cement the tube to it or anchor it somehow. SS and LS rock >would probably transmit the waves a whole lot better that anything above >it... I wish I had hard rock around here!!! > John Hernlund Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Palmdale Bulge Date: Sun, 19 Oct 1997 09:43:43 +1200 Frank, You may still get low level activity, that is what is happening on the Apline Fault (the plate boundary) down the spine of the Sth Is. of New Zealand. Technically the fault is locked and it unlocks in a major event every ~250-300 odd yrs. That time is again up in about 20 yrs. But there are still minor, M1-4, events on and around the fault. the section that is "locked" is ~ 300 km long, and there has multiple M7 + events on the sections at either end in the last 100 yrs. Dave At 02:04 PM 10/18/97 -0700, you wrote: >Greetings All: >Yesterday, there was an earthquake (small one) listed as being on the San >Andreas >fault near Palmdale, CA . Isn't it unusual to have an earthquake (even small >ones) on a section of the fault that is supposedly locked? Check out the >item in qustion here! >http://quake.wr.usgs.gov/recenteqs/Quakes/sc9026859.html >Please let me know what your thoughts are about this one. >Thanks, >Frank... Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Palmdale Bulge Date: Sat, 18 Oct 1997 17:55:19 -0700 (PDT) Hi Dave: Thanks for your explanation about the small tremors along the locked plate boundary. I reasoned this was kind of important because of the significance that is placed on a slightly larger event when it occurs within five miles of the San Andreas fault. They usually will make a statement of a low level watch for the next few days in case of a larger event. I think the cutoff point would be if it was of a magnitude 5.0 or higher and would cause the alert to be active. Best regards, Frank... mail to: frankcnd@.......... >Frank, > You may still get low level activity, that is what is happening on the >Apline Fault (the plate boundary) down the spine of the Sth Is. of New >Zealand. Technically the fault is locked and it unlocks in a major event >every ~250-300 odd yrs. That time is again up in about 20 yrs. But there >are still minor, M1-4, events on and around the fault. > the section that is "locked" is ~ 300 km long, and there has multiple M7 >+ events on the sections at either end in the last 100 yrs. > >Dave > > > >At 02:04 PM 10/18/97 -0700, you wrote: >>Greetings All: >>Yesterday, there was an earthquake (small one) listed as being on the San >>Andreas >>fault near Palmdale, CA . Isn't it unusual to have an earthquake (even small >>ones) on a section of the fault that is supposedly locked? Check out the >>item in qustion here! >>http://quake.wr.usgs.gov/recenteqs/Quakes/sc9026859.html >>Please let me know what your thoughts are about this one. >>Thanks, >>Frank... > >Co-ordinator: >New Zealand >Public Seismic Network > Dave A. Nelson ZL4TBN > 24 Jensen St., > Green Is., Dunedin, > South Is.. New Zealand. > >http://psn.quake.net/dave/home.htm > >IF there indeed are other parallel universes... I can now rest in the >knowledge, that in at least one of them, I am filthy rich and drive a red >Ferrari > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Bill Scolnik Subject: Re: Temperature control Date: Sat, 18 Oct 1997 22:14:27 -0400 (EDT) For what it's worth, the Geotech seismometers had a series of resistors in the top of the cover that drew approximately 35 watts which they used as a heater. This was evidently enough to create the necessary temperature gradient inside the enclosure. Bill Scolnik _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: sensor burial Date: Sat, 18 Oct 1997 20:48:37 -0700 (MST) On Sun, 19 Oct 1997, David A. Nelson wrote: > unfortunately wont find accessable rocks on my property, other > than what is in my collection. > anyway how's your system going haven't heard from you for a while > dave Well, things are going very slowly. I still don't have the benioff in the ground, and the ASU seismometers are almost ready to go if I can ever get the computer people around here to cooperate (computer people are always the hardest to reach and slowest to finish a job on any college campus)! We received Larry's 16-bit card and 3-channel amp, but haven't gotten them going yet. Also, I have been doing some high pressure research in the labs on something called "Impedance Spectroscopy." This is also eating a lot of my time. Some time soon though, I'll send something to the event list that I receive on our seismographs... ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Erich F. Kern" Subject: Thermal Mass/ Low Pass Filter Date: Sun, 19 Oct 1997 12:42:01 -0700 Hi All, We all agree on the importance of thermal insulation to minimize the temperature fluctuations to which seismometers and other instrumentation are subjected. The degree to which the temperature fluctuates within the insulated envelope is also determined by the amount of inert thermal mass. A usefull analogy is a single section R-C low pass filter where the R is the thermal insulation and C is the mass absorbing or dissipating heat. Increase the R or the C and the period gets longer. I am suggesting that the addition of several 1.5 liter bottles of water (secured so they don't tip over onto your seismometer and screw up a nice recording) inside the insulated enclosure will attenuate the amplitude of temperature changes. If there's enough room for a gallon of water in each corner of the enclosure, so much the better. Ideally, this mass should be located at the top of the enclosure to preserve the stratification of air as Karl Cunningham and others pointed out when discussing the placement of resistors to provide heat. This is difficult considering the weight of water, and weight is what thermal storage depends on. I don't know whether bottles of water at the bottom of the enclosure might cause convection currents. They're a diffuse source/sink, not like the point source of a light bulb or resistor, so maybe they wouldn't cause much convection. An insulated enclosure I made for my magnetometers outdoors consists of a plastic 20 gal. trash can with a hole in the bottom just large enough to fit snugly over the mounting pier. The inside is lined with 3" fiberglass R=11 batting and the lid inside surface has a disc of 1.5" styrofoam set in spray-on urethane foam. For thermal mass, I poured in 150 lbs of DRY silica sand. The ~10" dead air space above the sand is occupied with loose fill fiberglass insulation. After a 2 day settling period, a temperature probe buried in the center of the sand showed a 24 hour fluctuation of 7 degrees F. at a time of year when outdoor ambient ranges 50 F. at night to 105 F. at 2 PM. This plastic trash can is dark green and so absorbs and emits heat easily, so I added some aluminized bubble wrap to the outside of the can. Regards, Erich ************************************************************* Please visit our web site at: http://www.dconn.com/FatQuartersSoftware Thank you *************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: GeE777@....... Subject: Re: Thermal Mass/ Low Pass Filter Date: Sun, 19 Oct 1997 17:22:45 -0400 (EDT) In a message dated 97-10-19 15:50:29 EDT, ekern@......... writes: << We all agree on the importance of thermal insulation to minimize the temperature fluctuations to which seismometers and other instrumentation are subjected. >> Why not record the temperature along with your data and subtract from your seismic data any any fluctuations caused by temperature changes? This should reduce the amount of bulky hardware needed. George Erich GeE777@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Walter Williams" Subject: Chatsworth Quake Date: Sun, 19 Oct 1997 19:05:23 +0000 Re; Chatsworth Quake Thanks to All. Walt Williams, 97.10.19 dfheli@.............. Woodland Hills, California, USA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: Temperature control Date: Sun, 19 Oct 1997 23:26:55 -0700 At 09:59 AM 10/17/97 -0400, Robert Barns wrote: >Hi gang, [snip] > Since a Shackleford-Gunderson operates part of the circuitry at DC, it >might not be as immune to wide temperature swings. Maybe Larry can give us >his thoughts on this. >Bob Barns > Do to its size I think the Lehman would be more sensitive to temperature changes. Living in California reduces the temperature extremes (thank god!) so I can't say for sure how my Lehman and SG sensor would do in temperatures below 0 F or above 100F. I don't think the electronics will be a problem, because I use high quality op-amps etc. The SG sensor is extremely sensitive to air currents inside the box that covers the senor. This can be fix by filling the inside of the box with foam rubber so that it occupies as much of the free space as possible without touching the sensor itself. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: Thermal Mass/ Low Pass Filter Date: Mon, 20 Oct 1997 14:02:42 +0100 Erich F. Kern wrote: > Hi All, > We all agree on the importance of thermal insulation to minimize the > temperature fluctuations to which seismometers and other instrumentation > are subjected. The degree to which the temperature fluctuates within the > insulated envelope is also determined by the amount of inert thermal mass. > .......... I am suggesting that > the addition of several 1.5 liter bottles of water (secured so they don't > tip over onto your seismometer and screw up a nice recording) inside the > insulated enclosure will attenuate the amplitude of temperature changes. If > there's enough room for a gallon of water in each corner of the enclosure, > so much the better. Ideally, this mass should be located at the top of the > enclosure to preserve the stratification of air as Karl Cunningham and > others pointed out when discussing the placement of resistors to provide > heat. This is difficult considering the weight of water, and weight is what > thermal storage depends on................................ > > An insulated enclosure I made for my magnetometers outdoors consists of a > plastic 20 gal. trash can with a hole in the bottom just large enough to > fit snugly over the mounting pier. The inside is lined with 3" fiberglass > R=11 batting and the lid inside surface has a disc of 1.5" styrofoam set in > spray-on urethane foam. For thermal mass, I poured in 150 lbs of DRY silica > sand. The ~10" dead air space above the sand is occupied with loose fill > fiberglass insulation. After a 2 day settling period, a temperature probe > buried in the center of the sand showed a 24 hour fluctuation of 7 degrees > F. at a time of year when outdoor ambient ranges 50 F. at night to 105 F. > at 2 PM....................... > Regards, > Erich Hi Erich, I like the water idea. I wonder if thermal blocks, of the type used in electric night storage heaters would have greater thermal inertia? I shall be piling up the bricks, and collecting water bottles soon!! Perhaps carefully placed BAFFLES may assist in preventing air currents just where they are least wanted. Your 7deg F temp variation is very impressive when compared with your 55 deg. ambient temp. variation. Regards, Albert Noble (England). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: Thermal Mass/ Low Pass Filter Date: Mon, 20 Oct 1997 09:31:34 -0700 prewar wrote: >... I like the water idea. I wonder if thermal blocks, of the type used > in electric night storage heaters would have greater thermal inertia? > ... Albert Noble (England). I would wonder if thermal blocks incorporate phase-change materials. If so, then they are probably higher temperature melting point salts and would have an interesting hysteresis effect on the process when (if) you take them through the phase-change temperature. If you don't take them through the phase-change, then my guess is that you would be paying excessive dollars (pounds!) for the thermal inertial. Water would be just as effective and much cheaper. Also with winter coming on (at least in the Nothern hemisphere), don't forget the antifreeze (unless you're prepared to use thermal storage blocks with a phase-change temperature of 0 degrees C and the nasty side effect of a strong temperature coefficent of expansion around the phase change!) Charles R. Patton patton@......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: GeE777@....... Subject: Re: Palmdale Bulge Date: Mon, 20 Oct 1997 14:09:22 -0400 (EDT) In a message dated 97-10-18 17:08:58 EDT, frankcnd@.......... writes: << Yesterday, there was an earthquake (small one) listed as being on the = San=20 Andreas fault near Palmdale, CA >> Hello All Please refer to the map in--- http://quake.wr.usgs.gov/recenteqs/ It appears there is more than the average number of small quakes in South= ern California during the last week. Much of these small quakes are near the area of the =91=92locked zone=92 on the San Andreas Fault. Ridgecrest, = at the south end of the Sierra Nevada Fault Zone has been active with small quak= es for quite some time. Note that now these quakes extend up north along th= e Sierra Nevada Fault Zone and south crossing the Garlock fault. I underst= and the Garlock Fault is a strike slip fault with the south side being east i= n respect to the north side. Yet this line of small quakes seems to be a n= ew extension of the Sierra Nevada Fault Zone as it is not offset by the Garl= ock Fault. Note a number of small quakes near the =91=92bend in the San Andr= eas Fault=92=92 , which is also in the =91=92locked=92=92 area. I don=92t want to =91=92cry wolf=92=92 unnecessarily, however should thes= e small quake patterns be ignored? Are these indications of the =91=92Big One=92=92? = Should there be more than just a low level alert for Southern California at this time?= I would advise all in Southern California to prepare for an emergency situation. Keep vehicle fuel tanks more than half full at all times and = be ready to shut off gas, electricity and water in homes and businesses in a hurry. George Erich GeE777@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: Thermal Mass/ Low Pass Filter Date: Mon, 20 Oct 1997 11:16:42 -0700 With the talk of thermal mass inside the enclosure, something comes to mind... I think there is a potential problem if the thermal mass is too large. When the outside air temperature is rising, a situation could exist where the air below the thermal mass is warming faster than the thermal mass itself. If the air below it ever got to a higher temperature than the thermal mass, there would be convection currents -- cooler air falling from the thermal mass. If the heater is mounted such that it heats the thermal mass, I think this might help since in a constant-temperature environment the thermal mass will always be warmer than any air in the enclosure. Under warming conditions though, the air in the enclosure will be warming, and so will the thermal mass -- but at a slower rate. What's important is to make sure the temperature of the air doesn't overtake the temperature of the thermal mass. I don't have a very good feel for this but, as someone suggested, measurements of the thermal time constants would be a good start. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: GeoMonitr@....... Subject: Re: HAM interested in earthquake prediction Date: Mon, 20 Oct 1997 14:20:52 -0400 (EDT) I DID check out the number of lost dogs and cats from the Humane Society in Santa Clara, Calif. around the time of the Loma Prieta quake, and there was a slight increase prior to the event, but not statistically significant. I did the same thing with the lost cat and dog count from the San Jose Mercury News, and there was a LARGE increase, but again, not statistically significant. Someone from the USGS suggested using the egg and milk counts from factory farms. These folks keep detailed records of grain consumed, output, weight fluctuations, etc. ANY event that affects their level of contentment (read here quake precursors) should be reflected in the production of eggs, milk, etc. Again, a simple phone call, but who's going to do it? Vince _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: GeoMonitr@....... Subject: Re: HAM interested in earthquake prediction Date: Mon, 20 Oct 1997 14:28:36 -0400 (EDT) The Haichang (sp?) quake was the only real success the Chinese had with quake prediction. About a year after that successful warning (thousands of lives saved by evacuation) there was another deadly quake that was NOT predicted, and I think they lost 100,000 people. The Haichang quake had many foreshocks, and the peasant population was trained in observing and reporting anomalous behavior in their livestock - - remember these are people close to the earth and their animals. All this is well documented in Tributsch's "When the Snakes Awake." The fellow in LA is Jim Berkland, and he was in the San Jose area (Never to be confused with LA) but has now retired and moved to Valley of the Moon, up in the wine country north of San Francisco. His method relied on window of hyperactivity caused by the moons' tidal forces, combined with the lost pet count. He's had some success, but was resoundingly ignored by the scientific community. My personal belief is that humans and animals may be able to detect electromagnetic signals from quake precursors, but only a fraction of quake exhibit such precursors. Vince _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: That mob microsoft Date: Tue, 21 Oct 1997 17:25:56 +1200 hi all, a little more humor to help the week go by, BTW its great to see the US courts standing up to Microsoft, $1.5 million a day fine ouch.... There was a pilot flying a small single engine charter plane, with a couple of very important executives on board. He was coming into the Seattle airport through thick fog with less than 10 miles visibility when his instruments went out. So, he began circling around looking for a landmark. After an hour or so, he starts running pretty low on fuel and the passengers are getting very nervous. Finally, a small opening in the fog appears and he sees a tall building with one guy working alone on the fifth floor. The pilot banks the plane around, rolls down the window and shouts to the guy, "Hey, where am I?" To this, the solitary office worker replies, "You're in a plane." The pilot rolls up the window, executes a 275 degree turn and proceeds to execute a perfect blind landing on the runway of the airport 5 miles away. Just as the plane stops, so does the engine as the fuel has run out. The passengers are amazed and one asks how he did it. "Simple," replies the pilot, "I asked the guy in that building a simple question. The answer he gave was 100 percent correct but absolutely useless, therefore, that must be Microsoft's support office and from there the airport is just five miles due East." Chow Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Erich F. Kern" Subject: Re: That mob microsoft Date: Mon, 20 Oct 1997 23:18:53 -0700 Dave, It's a mystery to me why anyone would express such obvious glee due to a large fine being levied against Microsoft. Where do you think that money is coming from? Or didn't you think that one through? Erich Kern ---------- > From: David A. Nelson > To: psn-l@............. > Subject: That mob microsoft > Date: Monday, October 20, 1997 22:25 > > hi all, > a little more humor to help the week go by, > > BTW its great to see the US courts standing up to Microsoft, $1.5 > million a day fine ouch.... > > > > > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Michael Chang Subject: Re: That mob microsoft Date: Tue, 21 Oct 1997 02:45:03 -0700 The fact that we'll ultimately share the cost of such fines, doesn't lessen the necessity of sending Microsoft the message of what it means to be a responsible corporate citizen, and that they are part of the community.. and don't own it. At 11:18 PM 10/20/97 -0700, you wrote: >Dave, >It's a mystery to me why anyone would express such obvious glee due to a >large fine being levied against Microsoft. Where do you think that money is >coming from? Or didn't you think that one through? >Erich Kern > > > >---------- >> From: David A. Nelson < >> To: psn-l@............. >> Subject: That mob microsoft >> Date: Monday, October 20, 1997 22:25 >> >> hi all, >> a little more humor to help the week go by, >> >> BTW its great to see the US courts standing up to Microsoft, $1.5 >> million a day fine ouch.... >> >> >> >> >> >> > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: HAM interested in earthquake prediction Date: Tue, 21 Oct 1997 11:10:01 +0100 GeoMonitr@....... wrote: > > ....................................... > My personal belief is that humans and animals may be able to > detect electromagnetic signals from quake precursors, but > only a fraction of quake exhibit such precursors. > > Vince > > _Hi Vince, There now appears to be much evidence that UFO sightings can mostly be explaned in terms of light caused by electomagnetic effects in highly stressed rocks. Tests done in labs. crushing rock, shows that they can emit in the visible spectrum. A very good book on this subject for all interested in earthquake precursors is..... ....EARTH LIGHT REVELATION by Paul Devereux. It sounds cranky, but it is not. It puts to rest all the UFO mumbo jumbo, and is very interesting re earthquakes. Published in England, BUT distributed in USA by.... ....Sterling Publishing, 387 Park Ave. South, NY. In MARFA, Texas, the (UFO?) lights are FREQUENT, but it is also near to earthquake areas. A map of your country showing earthquake centres and areas where moving lights have been seen, appears to indicate that more UFO's have been sighted near the maximum earthquake activity zones..... ......I wonder why?...! ( The UFO enthusiast will no doubt explain, that this is because the aliens wish to study our 'Quakes!!! Well, why not? ). Regards, Albert Noble (England) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: GeE777@....... Subject: NOTICE Date: Tue, 21 Oct 1997 16:07:40 -0400 (EDT) Printed in the Los Angeles Times, October 21, 1997 CALIFORNIA EARTHQUAKE AUTHORITY P. O. BOX 2082 KEENE, NEW HAMPSHIRE 03431 George Erich GeE777@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Caruso Subject: Re: HAM interested in earthquake prediction Date: Tue, 21 Oct 1997 22:08:37 -0400 (EDT) Perhaps one should think why these animals are sensitive. They are smaller, and more likely to be sensitive to their environment, their everysense is tuned to survival! STEPHEN CARUSO CET KB8UGH "Coincidence is a shortsighted mental delusion" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Bob Fryer Subject: Re: HAM interested in earthquake prediction Date: Tue, 21 Oct 1997 19:38:47 -0700 (PDT) Hello, On Tue, 21 Oct 1997 11:10, prewar < wrote: >GeoMonitr@....... wrote: >> ....................................... >> My personal belief is that humans and animals may be able to >> detect electromagnetic signals from quake precursors, but >> only a fraction of quake exhibit such precursors. >> >> Vince > _Hi Vince, > There now appears to be much evidence that UFO >sightings can mostly be explaned in terms of light caused >by electomagnetic effects in highly stressed rocks. > >Tests done in labs. crushing rock, shows that they can >emit in the visible spectrum. A very good book on this >subject for all interested in earthquake precursors is..... >...EARTH LIGHT REVELATION by Paul Devereux. >It sounds cranky, but it is not. It puts to rest all the >UFO mumbo jumbo, and is very interesting re earthquakes. >Published in England, BUT distributed in USA by.... >...Sterling Publishing, 387 Park Ave. South, NY. > >In MARFA, Texas, the (UFO?) lights are FREQUENT, >but it is also near to earthquake areas. > A map of your country showing earthquake centres >and areas where moving lights have been seen, >appears to indicate that more UFO's have been sighted >near the maximum earthquake activity zones..... >..... < > Regards, > Albert Noble (England) =46irst, my experience suggests that Albert's confidence in the works of Paul Devereux is justified. And I agree that a significant number of UFO reports are due to stressed rocks, but I think that 'mostly' is a bit of a stretch. There are many other factors. On Vince's comments, I go much farther: Yes, humans and animals ARE able to detect electromagnetic signals from quake precursors; but, _no_ to "only a fraction of quakes exhibit such precursors." I now think that it is safe to say that all earthquakes exhibit electromagnetic precursors, albeit there can be very wide variations in the signal characteristics. Instrumentation and recording capabilities available to the general public are simply not adequate for the needs. (And estimates of the death toll for the 1976 Tangshan quake go as high as 750,000. The Chinese admitted to 240,000, I believe.) My opinions are based on information that is not easily available to, or perhaps not understood by, the casual investigator: HelveticaHazenHelvetica, Robert M., "Perovskites," Scientific American, v258, 6, June 1988, pp74-81. "...natural superconducting ceramic minerals.... common in the earth.... exhibit a wide range of electrical properties...." See p76, columns 2 & 3. When you understand that some perovskites change shape, thus generating mechanical (acoustic) energy, and you study the Helmholtz resonator, you can then appreciate harmonic effects that drive animals from enclosed structures including burrows. Back to EM energy, ELF/brainwave frequencies have surprising characteristics: they penetrate nearly everything, and do not obey the 'inverse square' law. They travel great distances with little attenuation. Given this, with the many faults around the earth, it is a blessing that we don't 'hear' all the noise. Kirschvink demonstrated that magnetite in the brain offers a mechanism for reception of signals. Growing evidence strongly suggests that sensitivity involves both psychological and immunological aspects. ------------------ Last week, an investigator whom I had not heard of, stated that his equipment has allowed him to make VERY accurate predictions for several years. He gave a very promising reply to this query: We, including the earth sensitive people, are very interested to hear what you have been doing. Having focused on this area since 1982, I am well aware that the technical capability exists to measure the precursory phenomena to which the sensitives react. Have you seen the article which I posted in the CompuServe Earth Forum library several years ago, regarding the U.S. Navy? Have you run into any trouble with the military during the development of your equipment? Is this equipment/method[s] similar to that of David Farnsworth and Adam Trombly? Elizabeth Rauscher and William Van Bise? The VAN group? Are you willing to share some descriptions of your work? I realize that there may be some proprietary concerns. Where might I find the published references to your work? My own efforts over the past 18 months have been heavily weighted towards gathering the experiential material, from the sensitive people, which I have followed towards its psychological and physiological underpinnings. Note that my interests in perception predate Charlotte King's experience with Mount Saint Helens. ------------------------ Towards the true sensory capability of humans, I offer this recent post of information from an eminent researcher, to the "sensitive" people: Hi (Sensitives), The purpose of sending this item is to emphasize that the nature of our sensitivity to Electromagnetic energy *also* includes the cellular level. Of particular interest is the comment, **In other words, a threshold might not exist in such a system.** This is found at the end of a paragraph about 2/3 through the article. Translated: We _may_ react, in some fashion, to ANY alterations of EM fields, including stressed faults and brain waves. Take care, Bob http://www.mk.net/~mcf/mind_net/mnindex.htm =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D MindNet Journal - Vol. 1, No. 50 =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D V E R I C O M M / MindNet "Quid veritas est?" =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D The views and opinions expressed below are not necessarily the views and opinions of VERICOMM, MindNet, or the editors unless otherwise noted. The following is reproduced here with the express permission ofthe publisher, Frontier Sciences, Temple University. Permission is given to reproduce and redistribute, for non-commercial purposes only, provided this information and the copy remain intact and unedited. Editor: Mike Coyle < Contributing Editors: Walter Bowart Alex Constantine Martin Cannon Assistant Editor: Rick Lawler Research: Darrell Bross =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D WHISPERING BETWEEN CELLS: ELECTROMAGNETIC FIELDS AND REGULATORY MECHANISMS IN TISSUE By W. Ross Adey [MD] VA Medical Center & University School of Medicine, Loma Linda, California ---------------------------------------------------------------- Over the past 20 years, a series of observations has pointed with increasing certainty to an essential organization in living matter, physical in nature at a far finer level than the structural and functional image defined in the chemistry of molecules. This is indeed a new frontier. It neither ignores nor neglects the great accomplishments across centuries of biological research, studies that have led to our present knowledge of the exquisite fabric of living tissues, focused on the chemistry and molecular biology of cell ultrastructure. Rather, this new knowledge appears to build logically and sequentially from all that has gone before. Yet in many respects, it has been an uncharted ocean in both biological and physical sciences. Research with millimeter waves also supports concepts of free radical interactions in biological systems. At frequencies in the range 10 to 1000 GHz, resonant vibrational or rotational interactions, not seen at lower frequencies, may occur with molecules or portions of molecules. Studies in yeast cells over the past 15 years in athermal millimeter wave fields by Grundler and Kaiser(10) have shown that growth appears finely "tuned" to applied field frequencies around 42 GHz, with successive peaks and troughs at intervals of about 10 MHz. -- Huge SNIP -- In recent studies, they noted that the sharpness of the tuning increases as the intensity of the imposed field decreases; but the tuning peak occurs at the same frequency when the field intensity is progressively reduced. Moreover, clear responses occur with incident fields as weak as 5 picowatts/cm2. In a recent synthesis emphasizing nonthermal interactions of EM fields with cellular systems, Grundler et al.,(3) present models of the transductive sequence of EM field transductive coupling, based on magnetic field-dependent chemical reactions, including cytochrome-catalyzed reactions that involve transient radical pairs, and production of free radicals, such as reactive oxygen and nitric oxide, leading to a further highly cooperative amplification step.=20 Based on Frohlich's(11) model of interactions between an imposed field and high frequency (1012 Hz) intracellular van der Pol oscillators, they conclude that "imposed fields can be active even at intensities near zero." **In other words, a threshold might not exist in such a system.** Beyond the low energies of EM fields in the first transductive step, amplification of low-frequency signals at cell membranes relates to selective responses seen as windowed phenomena in both frequency and amplitude domains. Contending models have considered cyclotron resonance and calcium coordination compound interactions. -- Large SNIP -- Future research on submolecular transductive coupling will be diversified and increasingly dependent on new technologies, such as high resolution magnetic resonance spectroscopy and electro-optical techniques. These approaches may answer such challenging problems as structural modifications during receptor-ligand binding, vibration modes in cell membrane lipoprotein domains during excitation(14) and possible coherent millimeter wave emissions accompanying enzyme action. There is a reasonable prospect that bioelectromagnetics may emerge as a separate biological discipline, offering a unique vehicle in the development of a physical, as distinct from a chemical, biology. In little more than a century, our biological vista has moved from organs to tissues, to cells, and most recently to the molecules that are the exquisite fabric of living systems. There is now a new frontier, more difficult to understand, but of vastly greater significance. It is at the atomic level that physical processes, rather than chemical reactions in the fabric of molecules, appear to shape the transfer of energy and the flow of signals in living systems(15). References 1. Adey, W. R., 1988. Physiological signalling across cell membranes and cooperative influences of extremely low frequency electromagnetic fields. In: Biological Coherence and Response to External Stimuli, H. =46rohlich, ed., Heidelberg, Springer-Verlag. pp. 148-170. 2. McLauchlan, K., 1992. Are environmental magnetic fields dangerous? Physics World, January, 1992, 41-45. 3. Grundler, W., Kaiser, F., et al., 1992. Mechanics of electromagnetic interaction with cellular systems. Naturwissenschaften 79, 551-559. 4. Adair, R. K., 1991. Constraints on biological effects of extremely-low-frequency electromagnetic fields. Phys. Rev. A. 43(2), 1039-1048. 5. Bialek, W., 1983. Macroscopic quantum effects in biology. Ph.D. Thesis, Department of Chemistry, University of California, Berkeley.=20 250 pp. 6. Adey, W. R., 1992a. Collective properties of cell membranes. In: Interaction Mechanisms of Low-Level Electromagnetic Fields in Living Systems, B. Norden, C. Ramel, eds. Royal Swedish Academy of Sciences, 1989. Oxford University Press. pp. 47-77. 7. Adey, W. R., 1992b. ELF magnetic fields and promotion of cancer: experimental studies. In Interaction Mechanisms of Low-Level Electromagnetic Fields in Living Systems, B. Norden, C. Ramel, eds. Royal Swedish Academy of Sciences, 1989. Oxford University Press. pp. 23-46. 8. Frohlich, H., 1986. Coherent excitation in active biological systems. In: Modern Bioelectrochemistry, F. Gutmann, H. Keyzer, eds. New York: Plenum. pp. 241-261. 9. Adey, W. R., 1981. Tissue interactions with nonionizing electromagnetic fields. Physiol. Rev. 61, 435-514. 10. Grundler, W., Kaiser, F., 1992. Experimental evidence for coherent excitations correlated with cell growth. Nanobiology 1, 163-176. 11. Frohlich, H., 1986. Coherence and the action of enzymes. In: The =46luctuating Enzyme, G. R. Welch, ed. New York: Wiley. pp. 421-449. 12. Liboff, A. R., 1985. Cyclotron resonance in membrane transport.=20 In: Interactions Between Electromagnetic Fields and Cells. New York: Plenum Press. pp. 281-296. 13. Lednev, V. V., 1991. Possible mechanisms for the influence of weak magnetic fields on biological systems. Bioelectromagnetics 12, 71-76. 14. Christiansen, P. L., Eilbeck, J. C., et al., 1992. On ultrasonic Davydov solitons and the Henon-Heiles system. Phys. Lett. A 166, 129-134. 15. Trullinger, S. E., 1978. Where do we go from here? In: Solitons and Condensed Matter Physics, A. R. Bishop, T. Schneider, eds. Berlin, Springer-Verlag. pp. 338-340. If you wish to receive a copy of the Vol.3, No.2 issue of our journal, please e-mail me your street address and I will forward you a copy. I trust that you will find the above paper interesting and I look forward to any comments. Dr. Adey is to be commended for the fine work that he has done in this field. My best wishes to all, Nancy Kolenda, Coordinator Center for Frontier Sciences, Temple University, < ---------------------------------------------------------------- MindNet Journal Archive Filename: [mn150.txt] =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D End matter snipped. ----- earthquake WARNING research ----- --- animals, people, scientific evidence --- --- http://www.teleport.com/~bfryer --- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Re: Thermal Mass/ Low Pass Filter Date: Wed, 22 Oct 1997 09:12:38 -0400 Albert, = Please note that the temperature stabilization effort of Eric Kern was applied to a housing for , not seismometers. These two types of sensors have very different responses to temperature and temperature changes. I have done some work with the magentometer Eric is talking about. Its= output frequency is proportional to the magnetic field. The output freq.= at constant field also changes with temperature, i.e, it has a considerab= le temperature coefficient. When trying to see the smallest changes in fiel= d (magnetic storms, etc.), temperature changes confuse the interpretation = so that reducing the rate of change of temperature and the total temperature= swing helps. Thermostatting the sensor would be a greater help. The scheme I have tried is to strap a thermistor to the magnetometer and use = a reasonable amount of insulation. The temperature coefficient of the magnetometer was measured (crudely) and a computer records the frequency and the thermistor resistance. The program then calculates the freq. correction for the temperature indicate= d by the thermistor (as was suggested by George Eric). This improved the data quite a bit without the complication of thermostatting but thermostatting would be better if done carefully. Seismometers are only slightly (if at all) sensitive to temperature changes per se. As far as I'm aware, no professional seismometers are thermostatted (although my knowledge of these things is very limited). Th= ey are exquisitely sensitive to air currents, e.g., those due to temperature= gradients in their surroundings. Thus, it is far more important to minimize air currents than to reduce temperaure changes or the rate of temperature change. This is what Larry does by stuffing the space around= his S-G's. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: TMichel917@....... Subject: Address GEOSense Date: Wed, 22 Oct 1997 13:23:46 -0400 (EDT) Hi all, I'm looking for information about the GEOSense seismographs. Is somebody there who can send me the new GEOSense faxnumber? Thanks! Torsten _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: magnetometers/seismometers & 'tilting' at the moon. Date: Wed, 22 Oct 1997 20:02:34 +0100 Robert L Barns wrote: > Albert, > Please note that the temperature stabilization effort of Eric Kern was > applied to a housing for , not seismometers. These two > types of sensors have very different responses to temperature and > temperature changes. > I have done some work with the magentometer Eric is talking about. Its > output frequency is proportional to the magnetic field. The output freq. > at constant field also changes with temperature, i.e, it has a considerable > temperature coefficient. When trying to see the smallest changes in field > (magnetic storms, etc.), temperature changes confuse the interpretation so > that reducing the rate of change of temperature and the total temperature > ........................snip > Seismometers are only slightly (if at all) sensitive to temperature > changes per se. As far as I'm aware, no professional seismometers are > thermostatted (although my knowledge of these things is very limited). They > are exquisitely sensitive to air currents, e.g., those due to temperature > gradients in their surroundings. Thus, it is far more important to > minimize air currents than to reduce temperaure changes or the rate of > temperature change. This is what Larry does by stuffing the space around > his S-G's. > Bob Barns Hi Bob, Thanks for above advice. Reducing air currents is now my priority. My Hall-Effect sensors are the most temp. stable devices which I could obtain from electronic suppliers, here in England. Also intend to keep enclosure near temp.stable in winter/summer. The reason for Hall-Effect is an interest in measuring earth TILT as well as 'quakes. (I can imagine the frowns on many brows now. ) I'm probably over ambitious in this, but as a green beginner my enthusiasm shows no bounds. ( Yet !! ) My 1898 (!) book on seismology talks of earth tilt caused by the passage of the moon, so I wish to investigate. (by 'averaging' data every hour to look for non drift, non weather influences.). Regards, Albert Noble (England) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: peaches@............ (Donna Whitaker) Subject: Re: Address GEOSense Date: Wed, 22 Oct 1997 09:17:14 -1000 (HST) Torsten, Geosense 115 W. California Blvd. #304 Pasadena, CA. 91105 Ph. (818) 388-2826 No FAX listed. Models: PS-2-V Vertical Single Axis $495.00 PS-2-H Horz. Single Axis $545.00 PS-2-2A Two Axis (H-H or V-H) $795.00 PS-2-T Triaxial (H-H-V) $1,125.00 Extended low frequency response options. Hope this helps. Tony >Hi all, > >I'm looking for information about the GEOSense seismographs. Is somebody >there who can send me the new GEOSense faxnumber? > >Thanks! > >Torsten > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: GeE777@....... Subject: Re: magnetometers/seismometers & 'tilting' at the moon. Date: Wed, 22 Oct 1997 17:40:17 -0400 (EDT) Hello, Before I retired from exploration geophysics, I could give a technician lat and long, time and date and he would be able to tell me what affect the ''earth tide'' (not sea tide) would have on my gravity data at that point and time on the earth. It was calculated in a program in our mainframe computer. I'm sure thase programs must still exist and must be improved. Can anyone help? George Erich GeE777@....... In a message dated 97-10-22 15:09:20 EDT, prewar@.............. writes: << The reason for Hall-Effect is an interest in measuring earth TILT as well as 'quakes. (I can imagine the frowns on many brows now. ) I'm probably over ambitious in this, but as a green beginner my enthusiasm shows no bounds. ( Yet !! ) My 1898 (!) book on seismology talks of earth tilt caused by the passage of the moon, so I wish to investigate. (by 'averaging' data every hour to look for non drift, non weather influences.). >> _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Erich F. Kern" Subject: Thermal Mass Date: Wed, 22 Oct 1997 14:57:20 -0700 Bob Barns et al, Bob, you've pointed out something I haden't thought of which is one of the benefits of this forum. The bottom line of the point you made is that minimizing temp gradients and the convection currents which are driven by gradients are far more important than temp stability per se. Actually, the addition of thermal mass at the bottom of the enclosure could create convection currents as the outer walls of the box cool down at night. Karl Cunningham mentioned this effect too. OK, OK I take it back about adding thermal mass. As for magnetometers, a 7 degree / 24 hour temp range is something I can live with. I sited mine outdoors 80 feet from the nearest building to avoid power line transients, etc, and had thought about a thermostatically controlled heater but abandoned the idea in favor of insulation and thermal mass which has worked very well. I can see now that it might make things worse in a seismo enclosure. Regards, Erich Kern *************************************************************** Please visit our web site at: http://www.dconn.com/FatQuartersSoftware Thank you *************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roger Griggs Subject: Re: New beta release of WinQuake and SDR. Date: Wed, 22 Oct 1997 18:52:09 -0700 Larry, I have loaded your new versions of sdr and winqk32 and if you have not already found out from someone else there are some bugs in the winqk32. 1. There is no EXIT on the file menu drop down. 2. In the file menu, below "Print Margins" it seems to automatically add a list of files and directories (about 9 on mine). As you run the cursor down the list it automatically loads the contents of the first dir on the list into the OPEN FILE dialog box in the main window instead of letting you click on the one you want. 3. I get a timeout error when trying to retreave a replay from winquake. I will recheck your instructions again to make sure I have not missed something. I have added the two channel info into the setup and the replay button is active. Roger At 10:04 PM 10/14/97 -0700, you wrote: >Greetings, > >I just got finished with the next release of WinQuake, version 2.5, and >would like some beta testers to try it out. I also have a new beta release >of SDR, version 2.4, that goes along with the WQ release. > >The WinQuake release has two new features and some bug fixes. The two bug >fixes are: > >The Great Circle Distance Calculate dialog box was displaying bogus numbers >for the azimuth calculation. Thanks to Robert Barns for reporting this bug. > >The second bug was around the Data Integration feature. On 16 bit versions >it would crash on some event files. Thanks to Bob Lewis for reporting this >one. > >The two new features are both network related. If you are going to try this >release please save this email message. Its the only documentation I have >for the new features. > >The first feature allows the user to directly access report information >over the Internet. It uses the UNIX finger service (TCP/IP port 79) to get >report information directly from the source. This report information has >event information (location, time of origin etc) that can be used to update >event files. Before you had to use some other method to get the report into >a file local to the system and then have WinQuake read it in. With this new >feature all you have to do is select the finger server/host in a dialog box >and WinQuake will retrieve the information directly over the Internet. It >save the report/finger information in a file and then parse out the event >information and displays it in a list box. The report information can then >be used to fill in the header information of an event file or used in the >second new feature below. > >There's one big problem... This feature is only supported in the 32 bit >version. For WinQuake to access information over the Net it needs to have >access to sockets. The sockets under Win95 and NT are easier to deal with. >Since the 16 bit version of Windows is now obsolete I'm not going to spend >anytime supporting it. Sorry... > >To use this feature all you need to do is go to the Report dialog box. You >can use the Report tool bar icon or the File / Report menu item to open >this dialog box. There you will see a new button called "Load Network >Report". This button is grayed-out in the 16 bit version. After selecting >this button you will see a new dialog box. If you have the NETWORK.DAT file >in the same directory as WQ you should a list of finger commands/host names >in the list box. If you double click (or use the "Connect" button) on one, >WQ should attempt to connect to the finger server and download the file. >Obviously you will need to be logged onto the net to get any data back. If >everything works as planed the dialog box will close up when it finishes >collecting the data. > >The Report dialog report list should now have the new event information in >it. If there are any errors, the Network dialog box will stay open and an >error message should show up in the Status line. The "Directory" button >sets the default location for the report files that are created using this >feature. The actual name of the report file is based on the host name. I >replace all of the "." in the host name with a "_" and then tag on the end >".rpt". This file is then saved using the directory specified by this button. > >The Add, Del and Save buttons are used to manage the NETWORK.DAT file. This >file holds the information needed for the feature to work. This file must >be located in the same directory as the WQ exe file. You also need the >REPORT.DAT file. This file has the parsing information use to extract the >event information. It also needs to be in the same dir. as the WQ exe file. >Both DAT files are in the beta zip file. > >In the future WinQuake will be able to get other information using direct >connection to the Internet. This could be event files or other report >information that is not available as a finger service. I would like to get >the norcal.list file directly using http. This file has all of the local >events, even the ones smaller then the 2.0 cutoff of the >quake@.............. list. This list is available using http and maybe ftp. >What I need to do is figure out the protocol of both so I can have WQ use >these protocols to download data/files. > >The second new feature is only for SDR users. It is supported in both the >16 and 32 bit versions. This feature allows the user to request/replay an >event file using WinQuake. To use this feature you must have your SDR and >main Windows system (Win3.1, Win95 or NT) networked together using two NIC >cards. Many of the sdr users have there systems networked so I thought I >would add this feature. It uses the same SDR feature used to implement the >request data form at http://psn.quake.net/request.html. This form allows >the user to extract a PSN formatted event file from my SDR systems based on >a start time, number of minutes to save, channel etc. SDR then uses this >info and creates an event file. Its similar to doing a replay, but remotely. > >Setting things up to get this feature working is a little complicated so >here it goes... > >First you need to get the two systems networked together. I would suggest >loading Win95 on both systems if you are going to try doing this. In the >beta release of SDR there is a netwin95.txt file that explains how to do >this. Another file you need too read is sdrwin95.txt. This file explains >how to run SDR in the DOS only mode of Win95. If you get the network stuff >working you should be able to map a drive letter, say "D:" on your SDR >system so that it is the same drive as the "C:" (or other local disk) drive >on your Windows system. Another words, if you have a dir/path called >c:\sdr\event\ on your Windows system, and, if you have your sdr system >maps the D: drive to be the same as the C: drive on the other system, then, >d:\sdr\event\ will be the same directory, and, files can be shared between >the two systems. > >For this feature to work you will need two directories. One will hold the >temporary request information file that SDR reads for the replay >information, and the other will hold the returned event file. Create two >directories like c:\sdr\event and c:\sdr\request on your Windows system. >Now enter the shared drive and path information in the field "Request >Control File Path" under the F5 settings in SDR. If the SDR D: drive = the >C: drive on the Windows system then enter "d:\sdr\request\" for that menu >item. That's all you need to do the SDR side of things. SDR will look for a >request file in that dir. every 10 seconds. If it finds one, it tries to do >the replay and create the event file. > >For more information on how the request process works in SDR, please read >the request.txt file that comes with the beta release of SDR. > >Now for WinQuake. When WQ firsts starts up it looks for a file called >REPLAY.DAT in the same dir. as WQ runs out of. If it finds it, then the new >"Replay" button in the File Open dialog box will be enabled. If the file is >not there this button will be disabled. Since this button will be disabled >when you run the new WQ for the same time you will have to use the menu >item called "Replay Setup" under the File menu items. > >This dialog box is used to create and manage the REPLAY.DAT file. The first >item in this dialog box is the returned event file path that SDR will use >to place files in. Use the "Change" button to select the directory that you >will be using, like c:\src\event, to hold the returned event files in. Next >you need to add the channel information for each of your sensors you are >running. For each channel select the "Add" button. In the Add Replay info >dialog box add the File extension for that channel, like LC1. If you only >have one sdr system keep the SDR system number at 1. For the Control File >directory use the "Change" button and select the dir. you will be using for >the request control file, like c:\sdr\request. > >After entering the replay info you should be able to do a replay. The >Replay button should now be enabled in the File Open dialog box. In the >Replay dialog box you will see a series of edit boxes for the start time, >save length, channel etc. After filling in the start time and channel press >the "Replay" button. WQ will create a request file for SDR to read and then >waits for the event file to be created by SDR. If after ~40 seconds there >is no event file found, WQ will time out. If it does find the event file it >will close out the Replay dialog box and open the event file. The "Report" >and "Report Time" can be used to set the starting time based on the >currently selected report time. The Save Default check box is used to save >selected fields, marked with a * in the group box name, as default settings >for the next time you run WQ. > >The SDR beta release as only minor changes in it. While you do not need to >upgrade to it for the second WQ feature to work, it would be best if you >do. This version as some changes around how SDR handles request file errors. > >Thats it! The beta release for both the 16 and 32 bit version of WinQuake >and SDR can be download using the following URL's. > >32 bit WinQuake: >ftp://ftp.seismicnet.com/users/psn/software/wq32b1.zip or >ftp://psn.quake.net/software/wq32b1.zip > >16 bit WinQuake: >ftp://ftp.seismicnet.com/users/psn/software/wq16b1.zip or >ftp://psn.quake.net/software/wq16b1.zip > >SDR: >ftp://ftp.seismicnet.com/users/psn/software/sdr24b.zip or >ftp://psn.quake.net/software/sdr24b.zip > >Please use the ftp.seismicnet.com address if possible. This system is on a >higher speed link into the Internet then my 28.8k modem at psn.quake.net. > >The WinQuake zip files only contain the new exe and some dat files. After >unzipping the file all you need to do is copy the files over to your >working WinQuake directory. Make sure you stop the old version before doing >the copy. > >For the SDR release there is a new exe file and all of the current text >files I have for documentation. All you need to do is copy the sdr.exe file >over to your SDR system and restart it. > >If you run into any problems, of have suggestions on the new features (or >old ones) please let me know. > >Thats it, enjoy! > >-Larry Cochrane >Redwood City, PSN > > > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Second beta release of WinQuake now ready. Date: Thu, 23 Oct 1997 16:19:36 -0700 Hi, The two bugs that Roger reported (#1 and #2, not sure about #3) in WinQuake have been fixed, thanks Roger for the report. I also added the ability to download report files using FTP. New FTP report files can be entered in the Network Report dialog box as a URL. The URL must start with ftp://. Example: ftp://quake.usgs.gov/pub/www/QUAKES/CURRENT/norcal.list. Please note that on some systems upper and lower case directories and file names must match. I also added horizontal scroll bars to some of the list boxes. The main File Open and the Report dialog boxes now have one. The new beta release for both the 16 and 32 bit version of WinQuake can be download using the following URL's: 32 bit WinQuake: ftp://ftp.seismicnet.com/users/psn/software/wq32b1.zip or ftp://psn.quake.net/software/wq32b1.zip 16 bit WinQuake: ftp://ftp.seismicnet.com/users/psn/software/wq16b1.zip or ftp://psn.quake.net/software/wq16b1.zip Again, please use the ftp.seismicnet.com address if possible. This system is on a higher speed link into the Internet then my 28.8k modem at psn.quake.net. If there are no more bug reports in the next week or so I will go ahead and make a more formal release. So, if you see any problems PLEASE let me know ASAP. Also, if anyone sees any misspelled or wrong words in any of the menu or dialog boxes please let me know. Thats it for now... -Larry Cochrane Redwood City, PSN At 06:52 PM 10/22/97 -0700, Roger Griggs wrote: >Larry, >I have loaded your new versions of sdr and winqk32 and if you have not >already found out from someone else there are some bugs in the winqk32. >1. There is no EXIT on the file menu drop down. >2. In the file menu, below "Print Margins" it seems to automatically add a >list of files and directories (about 9 on mine). As you run the cursor down >the list it automatically loads the contents of the first dir on the list >into the OPEN FILE dialog box in the main window instead of letting you >click on the one you want. >3. I get a timeout error when trying to retreave a replay from winquake. I >will recheck your instructions again to make sure I have not missed >something. I have added the two channel info into the setup and the replay >button is active. > >Roger _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: Second beta release of WQ - right URLs. Date: Thu, 23 Oct 1997 17:58:28 -0700 Oops, the URLs should be: 32 bit WinQuake: ftp://ftp.seismicnet.com/users/psn/software/wq32b2.zip or ftp://psn.quake.net/software/wq32b2.zip 16 bit WinQuake: ftp://ftp.seismicnet.com/users/psn/software/wq16b2.zip or ftp://psn.quake.net/software/wq16b2.zip Sorry about that... -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: bzimmerman@............ Subject: Alabama? Date: Fri, 24 Oct 1997 09:09:39 -0500 (EST) M 4.9 in Alabama? That is one you don't see every day. We got a nice record here in Pennsylvania. I'll try and post it on my page after class. Are there any reports from the area ? Who knows the geology of the region well enough to explain this one ? Brian Zimmerman _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "John A. Thomas" Subject: Re: Temperature control Date: Fri, 24 Oct 1997 07:16:22 -0700 (PDT) Has anyone attempted to solve the air-current problem in SG type devices by evacuating the air from a container housing the sensor? I have a heavy old bell jar which would nicely fit the device I've been planning. Obviously, you wouldn't want to have vacuum pumps running continuously, so the container would have to hold a decent vacuum for a reasonable amount of time. Any thoughts? John Thomas jathomas@.......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: Temperature control Date: Fri, 24 Oct 1997 09:32:38 -0500 That is exactly where I am headed. My plan is to put each sensor in a piece of copper water pipe and evacuate the pipe. Solder an old metal can IC header into the pipe cap for electrical feed thru. You actually need a very hard vacuum to eliminate all convection currents so even outgassing of the stuff in the vacuum chamber can spoil things. I am hoping that the vacuum combined with the tiny spaces in the instrument will work well enough. Jim Hannon jathomas@.......... on 10/24/97 09:16:22 AM Please respond to psn-l@............. To: psn-l@............. cc: (bcc: James M Hannon/CedarRapids/Collins/Rockwell) Subject: Re: Temperature control Has anyone attempted to solve the air-current problem in SG type devices by evacuating the air from a container housing the sensor? I have a heavy old bell jar which would nicely fit the device I've been planning. Obviously, you wouldn't want to have vacuum pumps running continuously, so the container would have to hold a decent vacuum for a reasonable amount of time. Any thoughts? John Thomas jathomas@.......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Mike Stickney Subject: Re: Temperature control Date: Fri, 24 Oct 97 08:39:57 MDT John: The old Teledyne-Geotech long period seismometers used in the Large Apeture Seismic Array (LASA) in eastern Montana during the 1970's had sealed housings with a vent through the housing. The vent is threaded, and I'm sure was designed to be attached to a vacuum pump, although I don't know how much of a vacuum they actually operated in. I believe one concern for the vertical seismometers were changes in barimetric pressure that exerted bouyant forces on the mass. -Mike Stickney Montana Bureau of Mines and Geology ====================================== At 07:16 AM 10/24/97 -0700, you wrote: >Has anyone attempted to solve the air-current problem in SG type devices by >evacuating the air from a container housing the sensor? I have a heavy >old bell jar which would nicely fit the device I've been planning. >Obviously, you wouldn't want to have vacuum pumps running continuously, >so the container would have to hold a decent vacuum for a reasonable >amount of time. > >Any thoughts? > >John Thomas >jathomas@.......... > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Re: Temperature control Date: Fri, 24 Oct 1997 13:25:47 -0400 Jim Hannon, = I believe that a hard vac. is not necessary. My reply to John Thomas suggests an experiment that you too can do. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Re: Temperature control Date: Fri, 24 Oct 1997 13:25:50 -0400 Mike Stickney, Yes, variations in air pressure around a siesmometer will sh= ow as noise in the output. If the air density changes, the bouyancy effect = on the mass actually changes the effective mass. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Re: Temperature control Date: Fri, 24 Oct 1997 13:25:52 -0400 John Thomas, Sure, a vacuum, even not a very good one would solve the air current problem. I would guess that a residual pressure of a few mm would be fin= e. You could get some interesting data by observing the background noise level as you change the pressure. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Mike Stickney Subject: Re: Temperature control Date: Fri, 24 Oct 97 11:53:08 MDT Bob: I saw this effect very clearly following the 1980 Mt. St. Helens eruption. The long period seismometer at the World Wide Standardized Seismograph Network at Missoula, Montana made a huge, low frequency deflection several hours (I don't recall the transit time precisely) after the eruption. The recording apparently showed passage of a large pressure wave traveling through the atmosphere at sonic speeds. -Mike ====================================== At 01:25 PM 10/24/97 -0400, you wrote: >Mike Stickney, > Yes, variations in air pressure around a siesmometer will show >as noise in the output. If the air density changes, the bouyancy effect on >the mass actually changes the effective mass. >Bob Barns > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: Temperature control Date: Fri, 24 Oct 1997 13:12:32 -0500 Robert L Barns wrote: > > Jim Hannon, > I believe that a hard vac. is not necessary. My reply to John Thomas > suggests an experiment that you too can do. > Bob Barns > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L Bob, Yes an experiment is in order. My statement of a hard vacuum is based on what it takes to control convection based heat loss in a TEC cooled CCD cameras for astroimaging and also the operation thermistor vacuum gages that compare convection cooling with radiative cooling to measure the vacuum. These gages will read down to about 10 microns. It maybe that the convection continues down to these levels but the forces generated are too small to affect the sensor. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Arie Verveer Subject: Seismometer location Date: Sat, 25 Oct 1997 07:46:35 +0800 Hello All, Greetings from one of the silent PSN members and hopefully a soon to be active member. I'm slowly putting together a SG seismometer and wanted to ask a question about locating the seismometers. In my location, I have two outcrops of granite, one is located in the crawl space under the house and the other is located some 20 feet from the house. Assuming its one big lump of granite, do you think it would be pointless to construct a limestone shelter around the outside outcrop and just stick with the easier and more thermally insulated option of locating the device under the house. Your comments and experience would be most helpful. The data acquisition side of the SG seismometer is made up of Larry's 16 bit A/D card , SG amplifier, SG bits and a GPS time source. All of this is connected to a dedicated 486 33Mhz CPU. Locally, we have low-level activity and the very occasional strong quake from a nearby fault, but it should be possible to detect the larger events from Indonesia and across Australia to the Solomon islands. That's assuming my equipment is as sensitive as the seismometers used to gather the data from your distant teleseismic " WinQuake" files. This raises one more question, what do you think is the threshold at which an event should be sent to Larry's mailer? Personally I think, a magnitude 3 or greater for a local event in Australia and all reasonable "WinQuake" data from the overseas events, that is from Perth Western Australia. Any comments? All the best Arie Verveer The Eastern outskirts of Perth :- Western Australia. 116 East -32 South ajbv@............ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: shansen@........ (shansen) Subject: Re: Temperature control Date: Fri, 24 Oct 1997 20:32:50 -0400 (EDT) Convection effects pretty much disappear below about 10 Torr (10mm Hg). In the case of thermal conductivity vacuum gauges (e.g. convection enhanced Pirani gauges - "fancy" versions of thermistor gauges and the like), the gauge operates in convection mode most effectively from about 100 Torr to 1000 Torr (the typical upper limit for commercial gauges) and molecular conduction below about 10 Torr. In the 10 to 100 Torr range (approx) neither mode is very effective and the gauge response flattens out. The effect can be seen quite nicely if you look at the output of a convection Pirani at various pressures while quickly jogging a valve placed between the gauge and the vacuum pump. This introduces a forced convection effect in addition to the natural convection about the gauge's filament and the indication will show a spike. This effect disappears as a pressure of around 10 Torr is approached. In semiconductor vacuum systems, the initial pump down is done slowly to avoid turbulance which will redistribute particles. At 10 Torr, the main valves are opened fully to complete the pumpdown quickly, not a problem since breezes pretty much don't exist. I don't have a citation but there were vacuum clocks (mechanical); evacuated for the same purpose as is being talked about in this thread. Steve Hansen >Robert L Barns wrote: >> >> Jim Hannon, >> I believe that a hard vac. is not necessary. My reply to John Thomas >> suggests an experiment that you too can do. >> Bob Barns >> > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: Temperature control Date: Fri, 24 Oct 1997 20:06:03 -0500 shansen wrote: > > Convection effects pretty much disappear below about 10 Torr (10mm Hg). Thanks Steve, I guess I don't have as much of a problem with the vacuum as I thought. The soldered copper water pipe should hold for quite some time. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: Alabama? Date: Fri, 24 Oct 1997 20:36:34 -0600 PSN- I got into the office this morning just in time to drive two of our earthquake response team to the airport to fly to Mobile, Alabama with some portable autononmous digital seismographs (PADS). Actually the first info I got about the Alabama event was from the PSN-list which I saw as soon as I arrived at the office, and then I ran into my colleagues busy getting prepared to go. This afternoon when I was talking to some colleagues about the kind of studies of this earthquake that we could do, I was able to show them Frank Cooper's PSN record (Charlie & Terri Thompson's hadn't been posted then). I post info here when we find out what's happening, and maybe, answer some of Brian's questions. -Edward bzimmerman@............ wrote: > > M 4.9 in Alabama? That is one you don't see every day. We got a nice > record here in Pennsylvania. I'll try and post it on my page after class. > Are there any reports from the area ? Who knows the geology of the region > well enough to explain this one ? > > Brian Zimmerman > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: Alabama? Date: Fri, 24 Oct 1997 20:43:42 -0600 PSN- I am sorry that with the rush, I overlooked Bob Lewis's very nice record of the Alabama Earthquake until just now. -Edward -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: Temperature control Date: Sat, 25 Oct 1997 09:28:24 +0100 Jim Hannon wrote: > shansen wrote: > > > > Convection effects pretty much disappear below about 10 Torr (10mm Hg). > > > > I guess I don't have as much of a problem with the vacuum as I thought. > The soldered copper water pipe should hold for quite some time. > -- > Jim Hannon > Hi, If leakage is occuring, cannot the re-exhausting periods be greatly extended by connecting the vacuumed enclosure to a large reservoir, such as an old oxygen cylinder? This can be sited a fair distance away and act as a 'vacuum reservoir'.....excuse wrong terminology? Perhaps all the moving parts of seismos should be STREAMLINED in order to obviate the effects of moving air particles??.....Round section being superior to square etc. Regards. Albert Noble (England) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Arie Verveer Subject: Calibration device Date: Sat, 25 Oct 1997 18:15:15 +0800 Hi All Do you think it would be feasible to place a piezoelectric device under the leveling screws of a "S-G" seismometer and use such a device to calibrate the seismometer. I'm thinking of the "Piezo film kit [A34,808]" that Edmund Scientific sells, or a piezoelectric audible warning device or even a piezo speaker from one of those novelty greeting cards. The seismograph can move beat of happy birthday! But seriously, by feeding the device a low frequency sine wave then it may be possible to calibrate the device's frequency response. Do you think this idea has any merit or should I just forget it. Regards Arie Verveer ajbv@............ Western Australia _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: shansen@........ (shansen) Subject: Re: Temperature control Date: Sat, 25 Oct 1997 09:51:18 -0400 (EDT) >Albert Noble wrote: > >Hi, If leakage is occuring, cannot the re-exhausting periods be greatly >extended by connecting the vacuumed enclosure to a large reservoir, >such as an old oxygen cylinder? This can be sited a fair distance >away and act as a 'vacuum reservoir'.....excuse wrong terminology? >Perhaps all the moving parts of seismos should be STREAMLINED >in order to obviate the effects of moving air particles??.....Round >section being superior to square etc. > Perhaps but you might introduce more complications in terms of the line to the reservoir (e.g. leaks at either end) of outgassing from the walls of the reservoir. If the system is tight with minimal use of elastomeric seals, the pressure should remain in the low Torr range for quite a while. The initial pumpdown should be long to rid the system of adsorbed water. Warming the surfaces will help to outgas residual water. Thereafter, avoid exposure to atmosphere as much as possible to avoid more water coming into the system. Successive pumpdowns to restore vacuum will be much shorter because the system will be relatively clean. Steve Hansen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "John A. Thomas" Subject: Re: Temperature control Date: Sat, 25 Oct 1997 07:37:32 -0700 (PDT) This is interesting. I was thinking a rotary pump could pull all the vacuum I would need to eliminate significant convection currents. Do you think a diffusion pump would be required? Do you have any calculations on this? John Thomas jathomas@.......... On Fri, 24 Oct 1997, James M Hannon wrote: > > > > > That is exactly where I am headed. My plan is to put each sensor in a > piece of copper water pipe and evacuate the pipe. Solder an old metal can > IC header into the pipe cap for electrical feed thru. You actually need a > very hard vacuum to eliminate all convection currents so even outgassing of > the stuff in the vacuum chamber can spoil things. I am hoping that the > vacuum combined with the tiny spaces in the instrument will work well > enough. > > Jim Hannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "John A. Thomas" Subject: Re: Temperature control Date: Sat, 25 Oct 1997 07:41:35 -0700 (PDT) OK, I see where Jim Hannon is coming from. I hope that the forces in a rough vacuum would be insignificant, even though the cooling effects would not be. Still, this raises another question: The power dissapation ratings of electonic components would have to be de-rated, since convective cooling would be much less in the the vacuum. John Thomas jathomas@.......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: Temperature control Date: Sat, 25 Oct 1997 10:01:10 -0500 John A. Thomas wrote: > > This is interesting. I was thinking a rotary pump could pull all the > vacuum I would need to eliminate significant convection currents. Do you > think a diffusion pump would be required? Do you have any calculations > on this? > > John Thomas > jathomas@.......... > John, >From what Steve Hansen said it looks like a rotary pump will be quite sufficient. That means I can use my refrigeration service pump. The only electrical components that will be in my instrument are the coils for the LVDT and the feedback coil. Only the feedback coil has any potential to dissapate power and it will be completely embedded in an aluminum block which will be good contact with the copper housing. No convection cooling would be possible or necessary. I don't want to put anymore of the electronics in the enclosure because it is easier to fix that way. At work I design electronics that goes in aircraft that fly to 70000 feet. We have to be concerned with convection vs conduction cooling in this environment. Usually we don't worry too much about it and derate all components 50% as a standard practice. This is for everyday electronics. When you get to designing high power stuff you have to pay a little more attention to the details. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: Calibration device Date: Fri, 24 Oct 1997 22:30:09 -0700 Arie I have experimented with this a while back and it works. I used a disk sold by Radio Shack. The problem I encountered is the disk response is velocity dependent and so I was stumped with how to calibrate the disk. One could also make a shaking table with disks(two I would say) and actually shake the sensor as the ground would. The only way I can think to calibrate the disk is with an LVDT or other sensitive desplacement device. I also tried to to use the disk as a sensor itself but they have such a high natural frequency(Radio Shack has a response curve shown with theirs) that I couldn't get the gain or damping correct. Let me know what you find out.I think they are compact and simple if the electronics could be worked out. Barry Arie Verveer wrote: > > Hi All > > Do you think it would be feasible to place a piezoelectric device under the leveling > screws of a "S-G" seismometer and use such a device to calibrate the seismometer. > > I'm thinking of the "Piezo film kit [A34,808]" that Edmund Scientific sells, or > a piezoelectric audible warning device or even a piezo speaker from one of those > novelty greeting cards. The seismograph can move beat of happy birthday! > > But seriously, by feeding the device a low frequency sine wave then it may be > possible to calibrate the device's frequency response. > > Do you think this idea has any merit or should I just forget it. > > Regards > > Arie Verveer > > ajbv@............ > Western Australia > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: System output Date: Fri, 24 Oct 1997 22:40:30 -0700 Hi All I have been having an elecrtical problem for awhile and was wondering if anyone else experiences this also or could shed some light one the solution. When a large event is recorded on my system and the signal is clipped, why do I not get full scale count output with the computer(ie 4096 for a 12 bit system)? I get less than 2000. I have put +5 to -5 vts into the A/D and get the proper output so I know it's not the A/D. My electronics path from the sensor has gains all above one. It seems once and amp reaches the max all the others after would also. Any ideas. I wouldn't care except I think it's affecting my dynamic range. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: 'Quake prediction? Date: Sat, 25 Oct 1997 13:57:23 -0400 Hi gang, The enormous complexities inherent in predicting earthquakes are discussed in a recent item in Science magazine, Oct. 17, vol 278, pp 487-490. This is two critiques of an article in Science vol 275, 1997, p 1616 by= RJ Geller et. al. who concluded that prediction would probably never be possible. A response by Geller et. al. is included. Extensive lists of references are provided if you are inclined to dig further. If your local library does not have the magazine, it can probably get y= ou a photocopy. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: 'Quake prediction? Date: Sat, 25 Oct 1997 13:05:20 -0700 (PDT) >Hi gang, > The enormous complexities inherent in predicting earthquakes are >discussed in a recent item in Science magazine, Oct. 17, vol 278, pp >487-490. > This is two critiques of an article in Science vol 275, 1997, p 1616 by >RJ Geller et. al. who concluded that prediction would probably never be >possible. A response by Geller et. al. is included. Extensive lists of >references are provided if you are inclined to dig further. > If your local library does not have the magazine, it can probably get you >a photocopy. >Bob Barns > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > Hi Bob: Without spilling the beans about the entire article, what is the main reason given for not being able to predict an earthquake? Does this article give out any Web references for us to peruse that are about seismic predicting? Thanks, Frank mail to: frankcnd@.......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: shammon1@............. Subject: Re: BBS Phone numbers / Keep them or dump them? Date: Sat, 25 Oct 1997 20:37:27 -0700 shammon1@............. wrote: > > Hi Larry-- You bring up a good question. I have been wondering if the BBS > still brings value to the group. I moved the San Jose system from an old > AT to a 486-33 because the old 100M HDD was reaching end of life and the > bearings sounded like they were going to fall out. Over the last month I > have had it running in my workroom (it's wonderful when kids grow up and > leave home... ) and I switched it off last weekend. Your the first to > speakup. It's now 8:00 PM on a Sat night and I just put it back on-line. > > So, my question to the group is, is the BBS in San Jose of any value to > you given the WWW? Should I keep the BBS's on-line or pull the plug? If > you want to dial-in and look around the phone number is 408-226-0675. > > Regards, Steve Hammond BBS Sysop San Jose, California > > Larry Cochrane wrote: > > > > Hi There, > > > > I was wondering if your BBSs are still running? I tried calling San Jose > > and Pasadena and both are not answering. I did not try Charles. Since some > > of us have Web pages listing these numbers we should make sure that they > > are still active. So please let me know if your system is still up and > > running, or off line, so I can update my web page. > > > > Thanks, > > > > -Larry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: Seismometer location Date: Sat, 25 Oct 1997 21:31:14 -0700 At 07:46 AM 10/25/97 +0800, Arie Verveer wrote: > >Hello All, > >Greetings from one of the silent PSN members and hopefully a >soon to be active member. > >I'm slowly putting together a SG seismometer and wanted to ask >a question about locating the seismometers. In my location, I >have two outcrops of granite, one is located in the crawl space >under the house and the other is located some 20 feet from the house. >Assuming its one big lump of granite, do you think it would be >pointless to construct a limestone shelter around the outside outcrop >and just stick with the easier and more thermally insulated option of >locating the device under the house. > >Your comments and experience would be most helpful. I would first try locating the sensor under the house. This would be a lot easier etc... If you get too much noise from the house moving, or from people moving in it, I would then go for the outside location. > >The data acquisition side of the SG seismometer is made up of Larry's >16 bit A/D card , SG amplifier, SG bits and a GPS time source. >All of this is connected to a dedicated 486 33Mhz CPU. > >Locally, we have low-level activity and the very occasional strong >quake from a nearby fault, but it should be possible to detect the larger >events from Indonesia and across Australia to the Solomon islands. That's >assuming my equipment is as sensitive as the seismometers used to gather >the data from your distant teleseismic " WinQuake" files. Its hard to say... You should be able to receive a mid or high M7 anywhere on the earth. Depending on the distances, you may only get the low frequency surface waves, but you should be able to detect it. > >This raises one more question, what do you think is the threshold at >which an event should be sent to Larry's mailer? > >Personally I think, a magnitude 3 or greater for a local event in Australia >and all reasonable "WinQuake" data from the overseas events, that is from >Perth Western Australia. Any comments? > I would say any local event where you get a clear P and S wave. Some of the smaller local events are more interesting then the bigger ones. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: System output Date: Sat, 25 Oct 1997 22:43:24 -0700 Barry -- Here is a possible scenario... For purposes of talking, say you have a circuit with two stages -- the first stage is an amplifier and the second a low-pass filter. Suppose the first stage is outputting a full-scale signal of a frequency higher than the low-pass filter's cutoff. When the first stage reaches full scale, suppose the second stage is only at half-scale due to the filter. Then, the signal at the first stage peaks and starts back down and the second stage may not have had a chance to get much over half scale. With a little more signal, the first stage could even be clipping and the second stage not even near full scale. Does this sound plausible? There may be other explanations too. Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: System output Date: Sat, 25 Oct 1997 20:18:28 -0700 Karl It seems plausible. Most of my low pass filters are set for 10hz. I'll have to check the FFT for the specific events to see how close to 10hz the signal gets. Barry Karl Cunningham wrote: > > Barry -- > > Here is a possible scenario... > > For purposes of talking, say you have a circuit with two stages -- the > first stage is an amplifier and the second a low-pass filter. Suppose the > first stage is outputting a full-scale signal of a frequency higher than > the low-pass filter's cutoff. When the first stage reaches full scale, > suppose the second stage is only at half-scale due to the filter. Then, > the signal at the first stage peaks and starts back down and the second > stage may not have had a chance to get much over half scale. With a little > more signal, the first stage could even be clipping and the second stage > not even near full scale. > > Does this sound plausible? There may be other explanations too. > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: SG output Date: Sat, 25 Oct 1997 20:27:31 -0700 Larry I have been playing around with my SG sensor. The recent Trinidad event only showed low frequency output. You have mentioned about taking two outputs,one before and one after the integrator and recording them. I think I'm going to try putting a summing amp after and adding the two. Because the integrator is inverting I will change the sign of the signal so the two signals have the same sign. What do you think? Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: GeE777@....... Subject: Re: System output Date: Sun, 26 Oct 1997 10:25:58 -0500 (EST) In a message dated 97-10-26 01:44:50 EDT, karlc@....... writes: << When the first stage reaches full scale, suppose the second stage is only at half-scale due to the filter. >> I f I remember my electronics studies, when you clip a signal in a linear amplofier, you make higher frequencies, double or triple, depending on the type of distortion. Your second stage, the low pass filter, will attenuate these distorted signals which now are higher frequency. All stages of a linear amplifier must not be driven to distortion. to preserve the signal as true as possible. Could you put your low pass filter as the first stage? George Erich GeE777@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: System output Date: Sat, 25 Oct 1997 21:01:55 -0700 George That's a thought. I know square waves have high frequency components due to the corners. I wasn't thinking of a clipped wave as square before. I'll check how my filters and amps are arranged Barry GeE777@....... wrote: > > In a message dated 97-10-26 01:44:50 EDT, karlc@....... writes: > > << When the first stage reaches full scale, > suppose the second stage is only at half-scale due to the filter. >> > > I f I remember my electronics studies, when you clip a signal in a linear > amplofier, you make higher frequencies, double or triple, depending on the > type of distortion. Your second stage, the low pass filter, will attenuate > these distorted signals which now are higher frequency. All stages of a > linear amplifier must not be driven to distortion. to preserve the signal as > true as possible. Could you put your low pass filter as the first stage? > > George Erich > GeE777@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Calibration device Date: Sun, 26 Oct 1997 13:43:43 -0500 Arie, Using a piezoelectric transducer might well work for getting the frequency response of a seismometer. However, I don't see any way to use this to get a velocity calibration in= common units such as cm/sec. since you will not know how far the transduc= er acutally moves the seismometer. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Magnetic bridges Date: Sun, 26 Oct 1997 13:43:52 -0500 Hi gang, I've observed an amusing phenom which may reduce the tedium of your dai= ly commute in the car. I have an automobile compass mounted on the dash (often useful in the wil= ds of north Jersey). It is just an ordinary undamped compass--not a flux ga= te or anything fancy. = I frequently get a sudden deflection when passing over each end of a bridge at normal speeds. These are someimes violent--the pointer sometim= es goes around a full 360 deg. or so. By bridge, I mean the minor ones over= a dip in the territory or a creek. A big bridge such as the Geo. Washingto= n is not required. The blips usually but not always occur only at the ends of the bridge--the compass usually points in the proper direction while between the two ends. A long bridge sometimes has an additional blip or two between the ends. I have never seen a blip when passing under an overpass. I guess this = is consistent with the observation of normal deflection in the center of a bridge since going under an overpass is away from its ends. I have not done the obvious experiment of walking over a brige with compass in hand to observe the static deviations. Since I'm not the outdoors sort, I'll leave that to one of you. I postulate two possible sources for the bridges' magnetism: 1. The steel in the bridge cools thru the Neel temperature in the earth's magnet= ic field during manufacture or 2. the steel is magnetized by the hammering when rivets are used to fasten the whole thing together. I suppose that = is possible that the higher permeability (compared to normal road materials)= of the steel simply concentrates the earth's field at the ends. I have n= ot tried to correlate the size of the effect with the orientation of the bridge. Bob Barns = _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: Magnetic bridges Date: Sun, 26 Oct 1997 13:15:18 -0600 Robert L Barns wrote: > I postulate two possible sources for the bridges' magnetism: 1. The > steel in the bridge cools thru the Neel temperature in the earth's magnetic > field during manufacture or 2. the steel is magnetized by the hammering > when rivets are used to fasten the whole thing together. I suppose that is > possible that the higher permeability (compared to normal road materials) > of the steel simply concentrates the earth's field at the ends. I have not > tried to correlate the size of the effect with the orientation of the > bridge. > Bob Barns A couple of comments. Number 1 is unlikely to cause the effect you are seeing as the pieces of steel would all be oriented diffenently in the bridge than when they were made and tend to cancel out. Both number 2 and the concetration effect are the likely causes. Ships use magnetic compases and the ship itself causes both the concentration effect and the being magnetized effect. To compensate the compass for the concentration effect there are two large iron balls located on each side of the compass. These are adjusted so that the combined magnetic effect of the balls and the ship are equal in all directions. The being magnetized is compensated for by a number of coils arranged around the compass. The current in the coils is adjusted to cancel out the ships field. An additional complication is introduced when the anti magnetic mines coils are turned on. These huge coils cancel out the overall magnetic field of the entire ship so as not to set off magnetic mines. When a ship goes into drydock for repairs it is usually necessary to recalibrate the whole system as all the pounding and sandblasting on the hull will change the field of the ship. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Re: Seismometer location Date: Sun, 26 Oct 1997 14:32:26 -0500 Hi gang, My results suggest that Larry may be unduly pessimistic about distant 'quakes. Here is the list of my 6 most distant 'quakes (out of about 130= ): Where 1997 UTC M = miles sig/noise E. New Guinea 4/5 12:23:30 6.1 8950 2 N. Sumatera 8/20 7:15:17 6 9253 5 Indonesia 6/24 23:4:53 6.1 9380 1.5 Coast. Cent. Chile 7/6 9:54:3 6.5 9800 120 W. Australia 8/10 9:20:33 6 10451 6 Mid Indian Ridge 8/20 13:51:15 6.4 11120 10 The mid Indian ridge of 8/20 was 161 deg. away--just about as far as possible. This is with an ordinary Lehman. The only improvement over the usual i= s that I have a 6-pole active low-pass filter with a knee at 0.08 Hz and th= e Lehman usually has a 30 sec. period. I normally do not do any FFT filtering which would improve the S/N somewhat. So I think that I can see a 'quake if it is about 6 or great= er unless it is off the ends of the Lehman (in the sensitivity nulls). Of course, the minimum detectable signal is usually set by your local seismi= c noise level. = Bob Barns (in seismically deprived New Jersey) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert Avakian Subject: Re: Magnetic bridges Date: Sun, 26 Oct 1997 15:39:05 -0800 I can think of other possibilities. The ends of the bridge may be the sites of a spontaneous potential difference (SP) with the soil, which could produce an observasble electromagnetic field. Also, any body with an acceptable magnetic susceptability lying in the earth's field will modify that field due to several factors. This is why magnetic surveying can detect faults in bedorck at depth. Prehaps the ends of the bridge are the sites of magnet signal. In any case, it would seem that the car itslef is the prime culprit. Aany movement through a field would induce a seconadry field w/i the car which would then jump the compass. If so, the effect would be less in a fibreglass car such as a 'vette. A special note to desparate parents of science students. This looks like a SUPER science fair project!!! Bob Avakian Jim Hannon wrote: > > Robert L Barns wrote: > > I postulate two possible sources for the bridges' magnetism: 1. The > > steel in the bridge cools thru the Neel temperature in the earth's magnetic > > field during manufacture or 2. the steel is magnetized by the hammering > > when rivets are used to fasten the whole thing together. I suppose that is > > possible that the higher permeability (compared to normal road materials) > > of the steel simply concentrates the earth's field at the ends. I have not > > tried to correlate the size of the effect with the orientation of the > > bridge. > > Bob Barns > > A couple of comments. Number 1 is unlikely to cause the effect you are > seeing as the pieces of steel would all be oriented diffenently in the > bridge than when they were made and tend to cancel out. Both number 2 > and the concetration effect are the likely causes. Ships use magnetic > compases and the ship itself causes both the concentration effect and > the being magnetized effect. To compensate the compass for the > concentration effect there are two large iron balls located on each side > of the compass. These are adjusted so that the combined magnetic effect > of the balls and the ship are equal in all directions. The being > magnetized is compensated for by a number of coils arranged around the > compass. The current in the coils is adjusted to cancel out the ships > field. An additional complication is introduced when the anti magnetic > mines coils are turned on. These huge coils cancel out the overall > magnetic field of the entire ship so as not to set off magnetic mines. > When a ship goes into drydock for repairs it is usually necessary to > recalibrate the whole system as all the pounding and sandblasting on the > hull will change the field of the ship. > -- > Jim Hannon > http://soli.inav.net/~jmhannon/ > 42,11.90N 91,39.26W > WB0TXL > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: GeE777@....... Subject: Re: Calibration device Date: Sun, 26 Oct 1997 19:04:14 -0500 (EST) Hi All, I sent a post on this before. However, it may not work with the seismometers you are using. I know it works with the seismometers used in seismic exploration. Apply a DC voltage to the coil to displace it to the end of the coil travel space, a known distance. Remove the voltage, and the resultant wavelet from the geophone is- 1) The DC voltage removed. 2) A voltage spike caused by the magnetic field collapsing around the coil when the DC voltage is removed. 3) A wavelet generated by the coil moving to the normal resting place. This wavelet, 3), is the step function response of the geophone when the coil comes to rest. A second derivative of this wavelet is the geophone response to a spike. If you can measure the distance you offset the coil with the DC voltage that was applied to the coil, you should be able to calculate the output sensitivity of your geophone in volts/in/sec or volts/cm/sec George Erich GeE777@....... n a message dated 97-10-26 13:49:12 EST, 75612.2635@.............. writes: << Using a piezoelectric transducer might well work for getting the frequency response of a seismometer. However, I don't see any way to use this to get a velocity calibration in common units such as cm/sec. since you will not know how far the transducer acutally moves the seismometer. Bob Barns >> _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: Temperature control Date: Sun, 26 Oct 1997 18:17:45 -0700 PSN- I figured that since there was so much discussion of temperature that I should put my two cents in, even if it weren't very relevant. In 1982, the Canadian Earth Physics Branch (Ottawa; the Bob Wetmiller was the chief of the field investigation) asked us, USGS Menlo Park, to help chase aftershocks of the 9 January 1982 magnitude 5.8 (MbLg) Miramichi Earthquake off in the boonies of New Brunswick (SE Canada just to the NE of the state of Maine) and loan them some portable autonomous digital seismographs (PADS), and Gene Sembera and I were part of that loan. The temperature was -30 C (~20 F) and the winds blew at 50 kph (~30 mph). The PADS recorders (3-channel Sprengnether DR-100s: one of the first commercial PADSs) were located in vacant huts in the epicentral area that we heated with kerosene heaters to a toasty 0 C and the sensors were installed outside, frozen to the ground and covered with snow. I decided to deploy two DR-100 at each of two sites, one equipped with a 3-component 2-Hz S6000 geophone (velocity transducer) and the other with an 3-component FBA (acceleration transducer), and the signals were recorded at a sample rate of 200 sps with 6-pole low-pass anti-alising filters at 50 Hz). The peak values of the velocity records (seismograms) and integrated acceleration records of the same events recorded by the co-sited PADS differed at most by 10%. The corresponding spectral ratios of the integrated acceleration to the velocity showed a maximum difference of ~3 dB (most frequencies were different by less than 10%) over the frequency band 2-50 Hz. Therefore, because the two sensors at each site recorded different orders of motion (velocity and acceleration) but produced comparable records, we were confident that the instruments were working reliably and were not seriously affected by the cold. -Edward Larry Cochrane wrote: > > At 09:59 AM 10/17/97 -0400, Robert Barns wrote: > >Hi gang, > [snip] > > Since a Shackleford-Gunderson operates part of the circuitry at DC, it > >might not be as immune to wide temperature swings. Maybe Larry can give us > >his thoughts on this. > >Bob Barns > > > > Do to its size I think the Lehman would be more sensitive to temperature > changes. Living in California reduces the temperature extremes (thank god!) > so I can't say for sure how my Lehman and SG sensor would do in > temperatures below 0 F or above 100F. I don't think the electronics will be > a problem, because I use high quality op-amps etc. The SG sensor is > extremely sensitive to air currents inside the box that covers the senor. > This can be fix by filling the inside of the box with foam rubber so that > it occupies as much of the free space as possible without touching the > sensor itself. > > -Larry Cochrane > Redwood City, PSN > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Caruso Subject: Re: Magnetic bridges Date: Sun, 26 Oct 1997 20:44:41 -0500 (EST) When dropped or hammered, do not magnets loose their strength? But then when they are heated the become magnetic? STEPHEN CARUSO CET KB8UGH "Coincidence is a shortsighted mental delusion" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Caruso Subject: Re: Calibration device Date: Sun, 26 Oct 1997 20:47:03 -0500 (EST) What about a plain speaker w/low freq sent by function generator. Build your own from Jameco for $20. STEPHEN CARUSO CET KB8UGH "Coincidence is a shortsighted mental delusion" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: Magnetic bridges Date: Sun, 26 Oct 1997 19:58:24 -0600 Stephen Caruso wrote: > > When dropped or hammered, do not magnets loose their strength? > But then when they are heated the become magnetic? > A permanent magnet can be destroyed by both heating or hammering. Both actions have similar effects, kind of like sirring things up. However if you were either to heat and then cool or hammer a magnet in the presence of a strong external magnetic field the magnet would tend to take on the applied field. This is what happens when hammering a ship or bridge except the external field is not so strong (ther earth's field). -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Snow Date: Mon, 27 Oct 1997 17:22:49 +1200 Ed, hope all is well with you in Colorado Ed, the snow storms look pretty severe on the TV news, in your and surrounding states. Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: reasonable Sth Pacific quake Date: Mon, 27 Oct 1997 22:41:57 +1200 0937 utc 3 min s-p from dunedin NZ, not large amp ~m6-6.5 Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: ACole65464@....... Subject: Re: Temperature controller Date: Mon, 27 Oct 1997 23:40:10 -0500 (EST) Hi PSN, Sorry to be getting into this thread a little late but could I add my 2 cents worth as well? A technician at NEIC who has worked on Streckeisen STS-1 vertical seismometers that are enclosed in a bell jar answered my questions as to how good a vacuum to use, and how long will the vacuum last. First he told me that the seismometer rests on a flat pyrex (he thinks) glass plate that is bonded to the supporting cement slab. A flat silicone rubber gasket lays on the plate and the bottom lip of the glass bell jar rests on top of the gasket. Vacuum grease is applied to both sides of the gasket to ensure an air tight seal between rubber and glass. A stop cock at the top of the bell jar is all that seals the top end after it is evacuated. He could not say how good the vacuum was but said it was not all that great and he had to use a vacuum pump supplied with the seismometer. I asked how frequently did the bell jar had to be pumped down and he said only after servicing etc did the bell jar get pumped down and not again until the jar was opened again, maybe a year or so later. I have been fortunate enough to closely examine an old Sprengnether 30 second vertical velocity seismometer that was once used in the WWSSN. It was not evacuated in any way, it had a simple 16 ga steel cover that went over the instrument. The cover is about 12" wide x 24" long x 24" high with simple embossed ribs running diagonally from corner to corner across the sides for extra rigidity. It had welded corners and the few fittings that protruded through the sides had rubber gaskets to seal out the air. Rubber gaskets were also fitted around the items mounted to the one piece cast metal (iron?) base. The sheetmetal cover was pulled down onto the base with 6 "J" bolts, 3 down each long side of the instrument. A 1/4" thick rubber gasket went between the the cover and base for the air tight seal. This system was apparently good enough for many years of acceptable recording quality. The seismometer was installed in a WWSSN vault that had passive heating panels mounted on the ceiling with the room heated to a toasty 65 deg F. The walls were lined with 2" thick sytrofoam insulation. That was their answer to controlling convection currents. Over each instrument also was a plywood box internally lined with 3" fiber glass insulation for additional help with a 3" gap between insulation and seismometer. I hope this gives some of you ideas as to what limits you need to go to. Bye for now, Allan Coleman, Seattle _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Event Date: Mon, 27 Oct 1997 13:06:59 -0800 All I picked up a teleseismic event on 10/28 @ 06:15:06 @ 6637k from Grass Valley. No info from USGS yet. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Event Date: Tue, 28 Oct 1997 20:18:26 +1200 Barry, an initial report said Mb5.8 Peru - Bolivia border but after seeing a few professional seismograms from around the world Tony (in Hawaii) and I tend to believe it to be somewhat bigger it totally dwarfs the Mb5.5 from the Kermadecs last nite Dave At 01:06 PM 10/27/97 -0800, you wrote: >All > I picked up a teleseismic event on 10/28 @ 06:15:06 @ 6637k from >Grass Valley. No info from USGS yet. > Barry > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Event UPDATE Date: Tue, 28 Oct 1997 20:25:47 +1200 Hi all 97/10/28 06:15:18 4.32S 76.63W 124.5 6.5Mb A NORTHERN PERU Dave At 01:06 PM 10/27/97 -0800, you wrote: >All > I picked up a teleseismic event on 10/28 @ 06:15:06 @ 6637k from >Grass Valley. No info from USGS yet. > Barry > Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Charlie Rond Subject: Re: Event Date: Tue, 28 Oct 1997 03:42:41 -0600 Barry, > I picked up a teleseismic event on 10/28 @ 06:15:06 @ 6637k from >Grass Valley. No info from USGS yet. Got it here. Charlie Rond -\/\--Public Seismic Network-Memphis rond@................ (901) 360-0302 [ free BBS ] http://gandlf.ceri.memphis.edu/~rond http://gandlf.ceri.memphis.edu/~rond/psn _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Event UPDATE #2 Date: Tue, 28 Oct 1997 20:58:15 +1200 Hi all, Here's the data from Caltech, NOTE: they use Mw Dave Subject: CMT Mw=7.2 NORTHERN PERU General region : NORTHERN PERU surface waves (3.0,3.5,7,7.5 mHz) Stations used : COR CTAO KONO PAB TUC Origin time: 1997 301 6 15 18 Original location (lat,lon,depth) : -4.30000 -76.6000 125 Moment tensor (x1.e26 dyncm) : Mrr : -7.240666 Mtt : 1.065872 Mff : 6.174794 Mrt : -0.871906 Mrf : 1.474340 Mtf : -2.157320 T-axis: moment= 7.161 plunge= 6.676 azimuth= 249.605 N-axis: moment= 0.289 plunge= 2.249 azimuth= 159.341 P-axis: moment= -7.450 plunge= 82.952 azimuth= 50.822 best double couple: Mo= 7.306(x1.e26 dyncm) Mw=7.2 tau= 10.7 nodal planes (strike/dip/slip): 342.18/ 38.37/-86.38 157.57/ 51.72/-92.87 Centroid location : -4.554 -75.832 103.724 Centroid time : 13.981 Variance reduction (%) : 87 o*********** ****ooooooo -**** ***oo oooo ---*** **- o ooo -----** **-- oo oo -----** *---- o ooo------* *----- o oo------* **----- o o -----** *-------o oo -----* **-------oo P o -----** **--------o + o ----** **--------oo o ----** *---------oo o ----* **T--------oo o ---** *----------oo oo ---* *----------oo o --* **---------ooo oo -** **----------ooo oo ** ***-------- oooo oo*** ****------ ooo**** ***********o Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Formula for horizontal pendulums. Date: Tue, 28 Oct 1997 14:33:35 +0000 Hello everyone, For anyone who is designing/building a SIMPLE horizontal pendulum, ( without using any electronic magic to alter its swing rate), you may like to have my formula linking swing rate/beam length/vertical offset. Knowing any two of these, allows one to calculate the third. (FORGIVE, if this has appeared before, but I haven't come across it in the archives.)...Yes, I'm STILL reading them !! DEFINITIONS. The vertical offset is the horizontal distance from the pivot POINT to the top termination of the suspension wire, when looking SIDEWAYS at the seismograph. (The top termination always being slightly 'forward' of the point, by this vertical offset amount as you all know. ) The beam length, measured from beam pivot point to suspension point, and the vertical offset are both measured in INCHES. T is the swing periodicity in seconds (that's swing to AND fro). It is based on the geometry of hor. pendulums, PLUS the formula for pendulum simple harmonic motion. It ASSUMES that the angle between beam and tension wire is 45 degree. (use tan of this angle for other configurations). (If anyone wishes to know how I derived above, contact me, as don't wish to clutter PSN with over large letters!). It also assumes that you are on the EARTH !! Moon dwellers etc. must revamp for different gravity acceleration figures ( 772.8 is x2 acceleration due to earth gravity, in inches/sec/sec) 2 beam length Vertical offset = ______________________ 2 ( T / 2 pi ) x 772 .. 8 ..................................................................................................... For example, if your beam length is 30" and you wish to have a swing periodicity of, say 20 seconds, the vertical offset in this case calculates out to something just over 1/8th. inch For 40 secs the vert. offset comes down to 1/32 inch, and so on. You can see from above that for long swing periods, particularly with short pendulum beams, the ENGINEERING standards MUST be fine, in order to achieve the smaller offset stable values necessary. The square of the beam length and square of T, are your enemies in this respect. The experienced builders out there will NOT need reminding of this! If any one has other formula for beams I would be VERY interested in seeing them. What about VERTICAL spring periodicity, when anchored part way along beams in vertical pendulums? Haven't been able to puzzle this out yet...the percentage stretch of the spring and ratio of beam length to anchor point to knife edge is involved. Regards, Albert Noble (England). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Formula for horizontal pendulums. Date: Tue, 28 Oct 1997 14:44:40 +0000 Hello everyone (again), Sorry for rotten layout...here's improvement... 2 beam length Vertical offset = _____________________ 2 ( T / 2 pi ) x 772.8 Regards, Albert Noble (England). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Walt Williams" Subject: SETI hdwe: stabilizing crystal oscillators Date: Tue, 28 Oct 1997 12:26:32 +0000 Hello All, An interesting thread in the PSN-L has been ongoing regarding thermal stabilization. I have seen other similar posts in the PSN-L, so I thought this might be relevant and of interest to others in the PSN-L. This was posted in the SETI-L reflector list. Dr. Shuch has kindly granted permission to cross-post this to the PSN-L. Best Regards, Walt Williams, 97.10.28 dfheli@.............. Woodland Hills, California USA ------- Forwarded Message Follows ------- Date: Tue, 28 Oct 1997 11:41:09 -0500 To: seti@....... From: "Dr. H. Paul Shuch" Subject: SETI hdwe: stabilizing crystal oscillators Cc: rcf@.............. Anyone who has built a crystal controlled oscillator (for use in a local oscillator chain or weak signal source) has probably noticed frequency drift as a function of temperature. The usual solution is to place the crystal in a proportionally controlled oven -- an expensive solution to be sure. At Microwave Update last weekend, Steve Kostro of Down East Microwave suggested an inexpensive solution: use a positive temperature coefficient (PTC) thermistor for simultaneous heat and regulation. One end of a 60 ohm (@ room temperature) PTC is physically soldered to the can of an HC-18/U crystal, which is itself grounded. The other end goes to +9 or +12 VDC. The thermistor draws (initially) about 200 mA of current, heats the crystal can up to about +60C, its resistance goes way up and it stops drawing current. As it cools a little, its resistance goes back down somewhat, it starts drawing some current, and heats up again. Makes for a self-regulating oven at about 40 degrees above ambient temperature! This really stabilizes the crystal frequency. I just tried it, and it works great. ----------------------------------------------------------------- H. Paul Shuch, Ph.D. Executive Director, The SETI League, Inc. 433 Liberty Street, PO Box 555, Little Ferry NJ 07643 USA voice (201) 641-1770; fax (201) 641-1771; URL http://www.setileague.org/ email work: n6tx@............... home: drseti@........... "We Know We're Not Alone!" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Robert L. Thomasson" <102073.3346@..............> Subject: SETI hdwe: stabilizing crystal oscillators Date: Tue, 28 Oct 1997 16:22:54 -0500 <> Pardon my ignorance, but what is SETI? Society for Extra Terrestial Investigation or something similar? Sounds kind of interesting. Regards, Bob Thomasson _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Walt Williams" Subject: FWD[2] SETI hdwe: stabilizing crystal oscillators Date: Tue, 28 Oct 1997 17:09:45 +0000 Hello Bob Thomasson, >------- Forwarded Message Follows ------- >Date: Tue, 28 Oct 1997 16:22:54 -0500 >From: "Robert L. Thomasson" <102073.3346@..............> >Subject: (Fwd) SETI hdwe: stabilizing crystal oscillators To: > PSN-L Mailing List Reply-to: >PSN-L Mailing List ><Dr. Shuch has kindly granted permission to cross-post this to the >PSN-L.>> >Pardon my ignorance, but what is SETI? Society for Extra Terrestial >Investigation or something similar? Sounds kind of interesting. >Regards, Bob Thomasson This is off topic, and I will keep this brief. acronym decodes: SETI League := Search for ExtraTerrestrial Intelligence League I understand this is a group of amateur and professional radio-astronomers, whose constituent member set are mostly ham radio operators. Their goal is locating technical extraterrestrial civilizations by looking for their high frequency energy emmissions using inexpensive 'amateur-home-brew' and or commercial radio equipment implemented for that task. Though there are no official ties to the (previously NASA funded) orthodox scientific SETI organization, some SETI-League members are affiliated with both organizations. I am not a representative of this group. Best Regards, Walt Williams, 97.10.28 dfheli@.............. Woodland Hills, California USA =============================== Date sent: Tue, 28 Oct 1997 15:05:39 -0500 To: "Walt Williams" From: "Dr. H. Paul Shuch" Subject: Re: Cross Posting Copies to: rcf@.............. At 11:49 AM 10/28/97 +0000, you wrote: >Hello Dr. Paul Shuch, > >I am a member of another reflector list: the "Public Seismic >Network-List". In this list there has been a discussion regarding >thermal stabilization. I was wondering if I might cross post your >interesting 'crystal-stabilization' post to that list? I have no objection whatever, Walt. Please do include a pointer to The SETI League web site, . Thanks. ----------------------------------------------------------------- H. Paul Shuch, Ph.D. Executive Director, The SETI League, Inc. 433 Liberty Street, PO Box 555, Little Ferry NJ 07643 USA voice (201) 641-1770; fax (201) 641-1771; URL http://www.setileague.org/ email work: n6tx@............... home: drseti@........... "We Know We're Not Alone!" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert Avakian Subject: Re: (Fwd) SETI hdwe: stabilizing crystal oscillators Date: Tue, 28 Oct 1997 23:22:50 -0800 Search for Extra Terrestrial Intelligence. I guess some folks have given up on finding any here on earth :> Robert L. Thomasson wrote: > > < Dr. Shuch has kindly granted permission to cross-post this to the > PSN-L.>> > > Pardon my ignorance, but what is SETI? Society for Extra Terrestial > Investigation or something similar? Sounds kind of interesting. > > Regards, Bob Thomasson > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: PSN map updates Date: Thu, 30 Oct 1997 00:49:42 +1200 hi ya all, two new additions to the USA map one is a replacement 1) Welcome Al Allworth near Gold Beach on the south coast of Oregon 2) and welcome David Wolny who has a system running at Mesa State College, Grand Jnct, Colorado Note:.... David replaces Frank Anderson on the map and in the database as he (Frank) is no longer in Grand Jnct and his e-mail address has been terminated. With these alterations, we have broken the big 50 with 51 stations now logged WOW!! there will be two new Australian stations on the world map soon.... one from Perth, W. Aust. and one from NSW once I get a bit more station data the dots will appear cheers from the deep south Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: another addition Date: Thu, 30 Oct 1997 02:11:36 +1200 hi again, on the Californian map there is now a new dot below Steve Hammond it is the site of the Almaden County School, Sth San Jose. Ted Blank looks after this system. Sorry Ted, Your school site has been in the database for a while just haven't had time to do the map update. with a much higher resolution map of Calif. now available from the USGS.... I will soon be upgrading the Calif. map to get rid of its chunky look.... That will keep the peace in the "Sunshine State" Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Greg Lyzenga Subject: Re: another addition Date: Wed, 29 Oct 1997 09:02:03 -0800 Dave Nelson wrote: >That will keep the peace in the "Sunshine State" > Oops! That may not keep the peace among Californians, since Florida is the "Sunshine State"! :-) California claims to be the "Golden State". We need to keep this list technically accurate after all! - Greg Gregory A. Lyzenga, Dept. of Physics, Harvey Mudd College -> lyzenga@................. <- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Dewayne (n0ssy) and Linda (n0uqf) Hill" Subject: Can a sound card be used as an A/D? Date: Wed, 29 Oct 1997 12:06:16 -0700 Hi to all, I have been interested in setting up a seismeter in my house for sometime. I have aquired some large magnets (from and IBM 3380 disk drive.) Now I have to get some type of A/D card and software for my PC. With no knowledge as to the inter-workings of the Sound Blaster sound card or the software to support it and my general knowledge of electornics is seem to me that all a sound card is is an A/D converter (it has an output - spearker out and an input - Mic in.) I am want to know if anyone has tried to connect the output from a senseing coil straight into a sound card. Can this type of connection be made to work? Any info would be helpful. Regards, Dewayne Hill _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: jim cristiano Subject: Re: Can a sound card be used as an A/D? Date: Wed, 29 Oct 1997 12:27:37 -0800 Dewayne (n0ssy) and Linda (n0uqf) Hill wrote: > Hi to all, > With no knowledge as to the inter-workings of the Sound Blaster sound > card or the software to support it and my general knowledge of > electornics is seem to me that all a sound card is is an A/D converter > (it has an output - spearker out and an input - Mic in.) > > I am want to know if anyone has tried to connect the output from a > senseing coil straight into a sound card. Can this type of connection > be made to work? > > Any info would be helpful. > > Regards, Dewayne Hill Hi Dewayne, Yup, I tried it just for laughs using my SoundBlaster16 card in my work computer. The problem is that the lowest sampling rate is 11025 Hz. Windows has a voice recorder that works with the sound card but it's lowest sampling rate is ~8kHz, you're really going to use up the big-a-bytes at that speed. The other problem is the frequency response of the sound card at very low frequencies. I think everyone would agree that if you're going to do it, do it with one of Larry's ADC cards. Jim cristiano@........... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: another addition Date: Thu, 30 Oct 1997 09:42:16 +1200 Well I guess someone was going to haul me over the coals.... thanks Greg.... I didn't know Florida was so named about the only thing I was really sure of is that New York is known worldwide as the "Big Apple" why ??? I have never heard. well that's the good thing about this group, we shape not only info about our hobby.. seismology... but also a bit about the world around us chow Dave >Oops! That may not keep the peace among Californians, since Florida is the "Sunshine State"! :-) >California claims to be the "Golden State". We need to keep this list >technically accurate after all! - Greg Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Francesco" Subject: R: Can a sound card be used as an A/D? Date: Thu, 30 Oct 1997 01:24:42 +0100 Hi to all, i'm busing to build my sismo station in italy with other friends Roberto and Giovanni. I have installed the horizontal long period sensor, built by Elkron Srl (Bologna, Italy). It's a good instrument, from many years used by Roberto Pozzo for his meteo-sesismic station on Nizza Monferrato. Now, the most important problem is the A/D converter card for the computerized analysis. Unfortunately, the Larry's card is not compatible with the analog imput mark, like I have had way already of audit with my friend Giovanni Rotta. In italy, I don't succeed to find no that cause th= e card or I have found one of it, but too high price. Could I use a Sound Blaster? His tension of analog input is < 1 volt. The output of the sensor is 0/ 5 volts, but before the entry into Sound Blaster is possible apply a reduction gear of strain The Sound Blaster has a response of frequency < 20 Khz. It could be good for our custom. This card it I want to use to run SDR. It's possible all this? Thank you for the responses ---------- > Da: jim cristiano > A: PSN-L Mailing List > Oggetto: Re: Can a sound card be used as an A/D? > Data: mercoled=EC 29 ottobre 1997 21.27 > = > Dewayne (n0ssy) and Linda (n0uqf) Hill wrote: > > Hi to all, > > With no knowledge as to the inter-workings of the Sound Blaster sound= > > card or the software to support it and my general knowledge of > > electornics is seem to me that all a sound card is is an A/D converte= r > > (it has an output - spearker out and an input - Mic in.) > > = > > I am want to know if anyone has tried to connect the output from a > > senseing coil straight into a sound card. Can this type of connection= > > be made to work? > > = > > Any info would be helpful. > > = > > Regards, Dewayne Hill > = > Hi Dewayne, > Yup, I tried it just for laughs using my SoundBlaster16 card in my > work > computer. The problem is that the lowest sampling rate is 11025 Hz. = > Windows has a voice recorder that works with the sound card but it's > lowest sampling rate is ~8kHz, you're really going to use up the = > big-a-bytes at that speed. The other problem is the frequency respons= e > of the sound card at very low frequencies. > = > I think everyone would agree that if you're going to do it, do it wit= h > one of Larry's ADC cards. = > = > Jim cristiano@........... > = > _____________________________________________________________________ > = > Public Seismic Network Mailing List (PSN-L) > = > To leave this list email listserver@............. with the body of the = > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Pete Subject: AD Converter Date: Wed, 29 Oct 1997 23:06:54 -0800 PSN, I have an 8 channel 10 bit A to D converter that works on a parallel port. It has a chart recorder software program with it. The program does not really work as a seismic data recorder because of the size of the files it produces. I am thinking of writing a program that will work just like SDR. Because it is 10 bits, would it be a waste of time? The cost of producing a AD converter of this type is extremely cheap! I can sample up to 4000 times a second if I want to. Perhaps I could make the files compatible with SDR? I plan to buy an AD converter from Larry but it will be a few months because I'm on a tight budget. Thanks, Pete Fleming _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: SG output Date: Thu, 30 Oct 1997 00:49:59 -0700 Hi Barry, I'm not sure about summing the two together. What type of signal would that produce? Give it a try.... -Larry At 08:27 PM 10/25/97 -0700, you wrote: >Larry > I have been playing around with my SG sensor. The recent Trinidad >event only showed low frequency output. You have mentioned about taking >two outputs,one before and one after the integrator and recording them. >I think I'm going to try putting a summing amp after and adding the two. >Because the integrator is inverting I will change the sign of the signal >so the two signals have the same sign. What do you think? > Barry > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: GeE777@....... Subject: Re: Can a sound card be used as an A/D? Date: Thu, 30 Oct 1997 05:14:32 -0500 (EST) Hi Dwayne, I thought of that but found the sample rate to be excessively high and wasting memory for the frequencies we are interested in. At the present time I am interested in only local seismic events so I use a seismic exploration type geophone connected to a MultiPurpose Lab Interface by Vernier Software, of Portland, Oregon, USA I sample the data every 8 milliseconds and run it through a home brew amplifier and anti-aliasing filter. In a message dated 97-10-29 14:13:02 EST, n0ssy@................ writes: << I am want to know if anyone has tried to connect the output from a senseing coil straight into a sound card. Can this type of connection be made to work? Any info would be helpful. >> _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: Can a sound card be used as an A/D? Date: Thu, 30 Oct 1997 02:32:57 -0700 I looked into sound cards when I first got into seismic recording a few years ago. The problem is the low end frequency response of the card. All of the specs I could find on the boxes had a ~10 Hz low end. We are dealing with much lower frequency range. Since sound cards only have too deal with the audio range, there is no need to design a sound card that can do DC, or, have a very low end. If someone knows of a "standard" sound card that can go lower then the normal audio range please let me know. As far as the sample rate, that can be handled in software. -Larry Cochrane Redwood City, PSN At 12:06 PM 10/29/97 -0700, Dewayne Hill wrote: >Hi to all, > >I have been interested in setting up a seismeter in my house for >sometime. I have aquired some large magnets (from and IBM 3380 disk >drive.) Now I have to get some type of A/D card and software for my PC. > >With no knowledge as to the inter-workings of the Sound Blaster sound >card or the software to support it and my general knowledge of >electornics is seem to me that all a sound card is is an A/D converter >(it has an output - spearker out and an input - Mic in.) > >I am want to know if anyone has tried to connect the output from a >senseing coil straight into a sound card. Can this type of connection >be made to work? > >Any info would be helpful. > >Regards, Dewayne Hill _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: Can a sound card be used as an A/D? Date: Thu, 30 Oct 1997 08:11:56 -0800 Although I haven't looked into it, the low-frequency response of a sound card's input is probably governed by a series capacitor and shunt resistor somewhere in the signal path to the A/D -- most likely right at the input to the card. There could be more than one stage of this too. One could increase the size of the cap(s) to reduce the low end cutoff, but the low-frequency stability (temperature drift) of the A/D and/or amplifiers on the card could be a problem. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jack Ivey Subject: RE: Can a sound card be used as an A/D? Date: Thu, 30 Oct 1997 11:53:39 -0500 Sound cards will probably all be AC coupled so that very low frequencies will be attenuated. One way to get around this problem would be to "chop" the signal with a high frequency (1 kHz?) carrier, so the signal the sound card sees is a 1kHz square wave whose peak-to-peak amplitude changes with the input voltage. This could be done with an oscillator, a couple of op amps and an analog switch. It will require demodulation in the software, which would be fairly simple. Demodulation could also get rid of the excess data. The scheme sounds odd, but it was used for DC amplifiers in the vacuum tube era and more recently for high precision amps. > >I looked into sound cards when I first got into seismic recording a few >years ago. The problem is the low end frequency response of the card. All >of the specs I could find on the boxes had a ~10 Hz low end. We are dealing >with much lower frequency range. Since sound cards only have too deal with >the audio range, there is no need to design a sound card that can do DC, >or, have a very low end. If someone knows of a "standard" sound card that >can go lower then the normal audio range please let me know. > >As far as the sample rate, that can be handled in software. > >-Larry Cochrane >Redwood City, PSN > > >At 12:06 PM 10/29/97 -0700, Dewayne Hill wrote: >>Hi to all, >> >>I have been interested in setting up a seismeter in my house for >>sometime. I have aquired some large magnets (from and IBM 3380 disk >>drive.) Now I have to get some type of A/D card and software for my PC. >> >>With no knowledge as to the inter-workings of the Sound Blaster sound >>card or the software to support it and my general knowledge of >>electornics is seem to me that all a sound card is is an A/D converter >>(it has an output - spearker out and an input - Mic in.) >> >>I am want to know if anyone has tried to connect the output from a >>senseing coil straight into a sound card. Can this type of connection >>be made to work? >> >>Any info would be helpful. >> >>Regards, Dewayne Hill >>> _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Re: Can a sound card be used as an A/D? Date: Thu, 30 Oct 1997 12:11:46 At 02:32 AM 10/30/97 -0700, you wrote: >I looked into sound cards when I first got into seismic recording a few >years ago. The problem is the low end frequency response of the card. All >of the specs I could find on the boxes had a ~10 Hz low end. We are dealing >with much lower frequency range. Since sound cards only have too deal with >the audio range, there is no need to design a sound card that can do DC, >or, have a very low end. If someone knows of a "standard" sound card that >can go lower then the normal audio range please let me know. > >As far as the sample rate, that can be handled in software. > >-Larry Cochrane >Redwood City, PSN Why couldn't you feed the output of the dc amp to a vco and then feed the vco output into the soundcard and fftdsp. Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: New Addition Date: Fri, 31 Oct 1997 12:08:28 +1200 hi ya 'll, please welcome our latest newcomer to the group map and database. Meredith Lamb, who hails from Denver, Colorado. Chow Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Can a sound card be used as an A/D? Date: Thu, 30 Oct 1997 18:36:06 -0800 (PST) Hi Larry: Yes, I know of a sound card that goes down to DC! It is the Multi-Sound Monterey from Turtle Beach. The sampling rate is the only snag as far as I can determine to be using it for seismic detection. The only way I can get it to work properly is if I use Spectra-Plus software for data acquisition. Actually, I used this setup to watch the 0-3 Hz region for a long time. If you try to capture the real-time data it will cost you plenty of hard drive space. I successfully used it in the data-logger mode. I sampled every 20 seconds and charted the amplitude to look for variations at a certain frequency. The air-core coil that I used as a sensor was very sensitive to 60 Hz. So, I installed a low-pass filter onto the front-end of the Monterey. Frank Condon mail to: frankcnd@.......... >I looked into sound cards when I first got into seismic recording a few >years ago. The problem is the low end frequency response of the card. All >of the specs I could find on the boxes had a ~10 Hz low end. We are dealing >with much lower frequency range. Since sound cards only have too deal with >the audio range, there is no need to design a sound card that can do DC, >or, have a very low end. If someone knows of a "standard" sound card that >can go lower then the normal audio range please let me know. > >As far as the sample rate, that can be handled in software. > >-Larry Cochrane >Redwood City, PSN > > >At 12:06 PM 10/29/97 -0700, Dewayne Hill wrote: >>Hi to all, >> >>I have been interested in setting up a seismeter in my house for >>sometime. I have aquired some large magnets (from and IBM 3380 disk >>drive.) Now I have to get some type of A/D card and software for my PC. >> >>With no knowledge as to the inter-workings of the Sound Blaster sound >>card or the software to support it and my general knowledge of >>electornics is seem to me that all a sound card is is an A/D converter >>(it has an output - spearker out and an input - Mic in.) >> >>I am want to know if anyone has tried to connect the output from a >>senseing coil straight into a sound card. Can this type of connection >>be made to work? >> >>Any info would be helpful. >> >>Regards, Dewayne Hill > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: SG output Date: Thu, 30 Oct 1997 08:43:37 -0800 Larry I was having problems with the opamp-coil feedback circuit so I am using the coil with a variable shunt resistor for damping. Like the Lehman I am taking the output from this coil as the high frequency input to to summing amp. For the low frequency I'm using the output from the integrator. I am fiddling with the input resistors to the summing amp so as to get the proper proportion of high and low frequency components. I guess what I really have is Lehman circuitry with an integrator from the pendulum deflection to increase the low frequency end(both velocity). Hopefully I can upload some local and teleseismic events to see how it performs. Barry Larry Cochrane wrote: > > Hi Barry, > > I'm not sure about summing the two together. What type of signal would that > produce? Give it a try.... > > -Larry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: Can a sound card be used as an A/D? Date: Fri, 31 Oct 1997 06:56:32 -0600 I suspect that there are more than one type of sound card that goes to DC. I set up a RealAudio WEB server here at work and they warn you that for best sound quailty you have to make shure there is no DC offset in your audio input signal to the sound card. This implies a DC response for the sound card. To deal with the large data files you can do what is referred to in the DSP world as decimation. In other words throw away all the samples in between the ones you want to keep. To do this with soundcard data you must either provide an external antialias filter with the apporpriate response or do the decimation with a decimation filter which reduces the bandwidth at the same time it removes samples. If you write your own driver for the sound card this can all be done in software as the data is stored to disk. Jim Hannon frankcnd@.......... on 10/30/97 08:36:06 PM Please respond to psn-l@............. To: psn-l@............. cc: (bcc: James M Hannon/CedarRapids/Collins/Rockwell) Subject: Re: Can a sound card be used as an A/D? Hi Larry: Yes, I know of a sound card that goes down to DC! It is the Multi-Sound Monterey from Turtle Beach. The sampling rate is the only snag as far as I can determine to be using it for seismic detection. The only way I can get it to work properly is if I use Spectra-Plus software for data acquisition. Actually, I used this setup to watch the 0-3 Hz region for a long time. If you try to capture the real-time data it will cost you plenty of hard drive space. I successfully used it in the data-logger mode. I sampled every 20 seconds and charted the amplitude to look for variations at a certain frequency. The air-core coil that I used as a sensor was very sensitive to 60 Hz. So, I installed a low-pass filter onto the front-end of the Monterey. Frank Condon mail to: frankcnd@.......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: A/D converters Date: Fri, 31 Oct 1997 09:58:00 -0500 Hi gang, A variety of A/D converters has been discussed lately. An important attribute of A/D converters is dynamic range and the recent discussion ha= s not made much mention of this. Even here in New Jersey where strong shaking is almost never seen (unle= ss I go out in the winter with a thin coat), 16 bits of resolution is not excessive. On July 16, 1996, Larry gave an admirable discussion of dynamic range a= nd other considerations. This is well worth looking up in the archives. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Robert L. Thomasson" <102073.3346@..............> Subject: A/D converters Date: Fri, 31 Oct 1997 11:07:33 -0500 Can anyone recommend any good books on digital signal processing? I've found a lot of titles listed on amazon.com, but at $75++ per book, I'm ki= nd of chicken to buy one without a recommendation. Thanks, Bob _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: A/D converters Date: Fri, 31 Oct 1997 10:43:58 -0600 >Can anyone recommend any good books on digital signal processing? I've >found a lot of titles listed on amazon.com, but at $75++ per book, I'm kind >of chicken to buy one without a recommendation. >Thanks, Bob It depends a lot on what you want to do and where you are coming from. Here are two books that are reccomended around here at work. Theory and Application of Digital Signal Processing by Rabiner and Gold Prentice-Hall Discrete-Time Signal Processing by Oppenheim & Schafer ISBN 0-13-216292-X Jim Hannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Robert L. Thomasson" <102073.3346@..............> Subject: Re: A/D converters Date: Fri, 31 Oct 1997 14:29:12 -0500 Jim, Thanks for the book references. <= > This is only peripherally related to psn business, so I'll keep it short and promise not to do it again. I'm a mechanical engineer (read electronically and softwarily challenged), and I work with industrial vibration monitoring equipment that takes an accelerometer signal, integrates it to velocity and/or displacement, then performs FFT's and th= e results can be stored and displayed in various graphical formats. I'd li= ke to understand the nuts and bolts of how these hardware/software systems work so I can modify them to suit my own purposes. If that's not practical, I just want to understand how they work. Regards, Bob Thomasson _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roger Baker Subject: Re: A/D converters Date: Fri, 31 Oct 1997 15:10:58 -0600 Friends, On the topic of A/D converters, the latest Radio Shack catalogue, p 173, has a nifty little two channel 12 bit converter called DATAQ that samples DC up to 250 samples per second and plugs into the serial port (you need another free serial port for your mouse). The company worked out the bugs dealing with industrial customers and has now branched out to the consumer market. They offer free phone support. It costs $100, and various other models are available for specialized applications. It is quite versatile and comes with easy to use software that lets you do setup and then record data from almost any analogue circuit up to 30 volts or so. In general it will turn your Windows 95 PC into a chart recorder for about any reasonable voltage level and sampling rate and specified file size you want. I got one and I love it and have not encountered any important deficiencies. It gets its own power from the port. I use it with an op amp buffer output from the analog circuit and about 35 feet of speaker wire to the device, which is about the size of a matchbox with screw terminals, and a five foot or so serial cable that comes with it leads to the computer port. On the other hand, you're probably better off with one of Larry's boards if your interests are strictly seismographic. --Yours, Roger Baker _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert Avakian Subject: Re: A/D converters Date: Fri, 31 Oct 1997 23:38:02 -0800 The cost of technical books is an all prevasive problem. Let me offer a couple of sites for everyone's consideration: abebook.com and interloc.com. I have dealt with dealers on both systems with complete satisfaction. ABE has a feature that lets you put in your want list on their computer and you recieve an E-mail if a matching item is posted on their system. Very slick. Bob Avakian Robert L. Thomasson wrote: > > Can anyone recommend any good books on digital signal processing? I've > found a lot of titles listed on amazon.com, but at $75++ per book, I'm kind > of chicken to buy one without a recommendation. > > Thanks, Bob > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: A/D converters - Dynamic Range Date: Sat, 01 Nov 1997 03:04:16 -0700 At 09:58 AM 10/31/97 -0500, Robert L Barns wrote: >Hi gang, >> On July 16, 1996, Larry gave an admirable discussion of dynamic range and >other considerations. This is well worth looking up in the archives. >Bob Barns I have this on the web at http://psn.quake.net/dynamic.txt. I'm not sure about the admirable part . -Larry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Concrete foundations and DECOUPLING Date: Sat, 01 Nov 1997 20:01:41 +0000 Hello, I see from list of PSN sites that many have large concrete blocks upon which the seismos are fixed. I too have a heavy concrete block, 2ft long x 1.5 ft wide x 2ft DEEP. The block is FLUSH with the ground surface, but ONLY the bottom 6 inches of the block is in contact with the ground. (It is pinned into the ground with 3/4 dia steel driven into earth at bottom last 6 inches). My reason for doing this was to decouple the block from any earth movements at ground level.......footsteps, SMALL roots of hedges and trees etc. I am now rather concerned that being situated on clay, then the inertia of a 1/5th ton block will not allow it to move as the earth beneath does. Should I 'fill in' the top 18 inches and ensure that ALL the block is in direct contact with earth or not ?? Will the block be decoupled and act as a cherry on top of jelly if I don't? If anyone with concrete blocks has considered above I would like to know of their experiences, and what they did. Thanks. Regards, Albert Noble (England). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Dennis Eckert" Subject: Seismic radio monitoring Date: Sat, 1 Nov 1997 13:36:26 -0800 I'm new to the list. Is anyone selling or offering as shareware a program that allows you to connect an audio cable from a radio receiver (like a scanner) to a SoundBlaster-compatible card? This would allow you to monitor the various radio transmitters broadcasting seismic signals. I've seen the site where you can buy a board to do this, but wondered if this other approach has been done. I enjoy monitor data traffic on radios, and there are a number of freeware programs that now work this way (take the audio from the radio receiver and input into the mike or line input of the sound card). Dennis Eckert KB7ST (Amateur Radio Operator) Flies Standard Cirrus sailplane (SV) In Western & Eastern Washington _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Willmore seismometer Date: Sun, 02 Nov 1997 17:17:46 +1200 hi all, I have borrowed a Willmore MKI or II vertical seismometer for a couple of months to try out. do any of you have practical experience in using one of these beasts. a few comments about it..... it is encased in a steel cylinder ~5" dia. and 10" high. weighs ~10lb (very solid) the top of the seismometer is adorned with a chromed steel carry handle, a levelling bubble, a single fine threaded screw which is screwed right down to clamp the internals during transportation and a red coloured "needle" in a 1" high perspex dome to indicate operation of the seismometer. It has a period that can be adjusted (by a setting inside) from 1 sec to 3 sec OK.... problem.... how/how much ... do I damped this beast at the moment I have a 3k resistor across the output of the coil and this does dampen it to some extent.... one comment on a MKIII unit said 7k resistive load I started at 10k and decreased value watching the results at present with ~3k if the seism. is tapped it will give ~6 cycles before returning to a flat line. The cycles decrease evenly so the overall waveform is triangular shaped (starting large p-p, dying off rapidly know what I mean??) Not having a lot of experience with longer period units it the above 6 odd cycles too much. I dont want it doing its own thing instead of faithfully recording ground movement The voltage output from this unit is huge compared to my geophones, so much so that event with the gain set at minimum on one of Larrys preamp brds. it was still overloading and I had to do component changes to substantially reduce the pre amps overall gain. for your thoughts Dave PS hope you all like the new Hi Res Californian PSN map I was trying to wait for someone to comment but couldn't resist any longer. oh dear I have no will power Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Al Allworth Subject: Re: Willmore seismometer Date: Sat, 1 Nov 1997 23:01:59 -0800 (PST) At 05:17 PM 11/2/97 +1200, you wrote: >hi all, > I have borrowed a Willmore MKI or II vertical seismometer for a >couple of months to try out. do any of you have practical experience in >using one of these beasts. Hi Dave, I have somewhere in my accumulation of Seismo info something that stated that critical damping should bring the impulse signal down to 1 percent in three cycles. If you loaded it with lower resistance to get this kind of damping it would also reduce the output to a more usable value. I am using 500 ohms to damp my seismometer. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Al Allworth Subject: Re: Willmore seismometer Date: Sat, 1 Nov 1997 23:04:01 -0800 (PST) I just thought of another question. What is the internal resistance of the seismometer? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Willmore seismometer Date: Sun, 02 Nov 1997 20:28:03 +1200 Hi Al, just went out and measured the coil resistance 500ohms at one stage I went as low as 560 ohms with a load resistor other willmores I have read about have coil resistances up to 8000 ohms Dave At 11:01 PM 11/1/97 -0800, you wrote: Hi Dave, >I have somewhere in my accumulation of Seismo info something that stated >that critical damping should bring the impulse signal down to 1 percent in >three cycles. If you loaded it with lower resistance to get this kind of >damping it would also reduce the output to a more usable value. I am using >500 ohms to damp my seismometer. Al Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: GeE777@....... Subject: Re: Willmore seismometer Date: Sun, 2 Nov 1997 06:16:01 -0500 (EST) Hello all, I know that we in the seismic exploeation business try to dampen our geophones so they will return to zero as soon as possible fron an impulse. That is, not ringing (cycling) [not enough damping] or slowly returning to zero [too much damping] In a message dated 97-11-02 02:04:04 EST, aallworth@........ writes: << I have somewhere in my accumulation of Seismo info something that stated that critical damping should bring the impulse signal down to 1 percent in three cycles. >> _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Calif/Nevada BDR Date: Mon, 03 Nov 1997 00:12:56 +1200 well all you californian guys a Mw5.7 must have given you gear a good workout Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: curtis Subject: re: Seismic radio monitoring Date: Sun, 02 Nov 1997 06:17:00 -0800 gm dennis and greetings list, take a look at http://www.relisoft.com/ . about half way down the page there are the keywords "Whistle a melody" which is the location of a "real time frequency analyzer", http://www.relisoft.com/freq.html , i use on my dec alphas' (it also works on the x86 platform). i use the 'line in' on a soundblaster (rather than the mic. input) and observe seismic transmitter activity (smile - at a minimum) while i am working on my other projects. i am also new to this list and have spent most of my (smile) 'entry time' reading documentation, with anticipation of building my own station. in due process, i will properly introduce myself to the list, but in the meantime, here's a little information. i have successfully optimized larry's 'WinQuake beta release' to work on my dec alpha xlt300/nt4.0/sp3/fx!32v1.2. fx!32 is digital's new x86 emulator. (fwiw) i have aprox. 18 years unix and 1 1/2 years nt back- ground (smile = nt newbie). i am located at 38.45n, 122.37w, on the side of an old volcano, at aprox. elevation 2600'. this area, on the charts, is known as "The Geysers" and the closest (now capped) geyser is aprox. a 15 min. walk through the woods from my front door. (smile) i have 'tinkered' with amateur seismology, for a long time, and when i finally get into 'building mode' (soon) will probably have a lot of questions so (chuckle) list beware. best2u, curtis - n6ect -- curtis - ufkartfm@........... - site administrator for Nobody I want Nobody to control my Life! How about You? http://www.netvideo.com/nobody _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: Calif/Nevada BDR Date: Sat, 01 Nov 1997 20:46:21 -0800 Dave I've picked up three so far. The main event on low gain . Will upload as soon as I get times etc. Barry David A. Nelson wrote: > > well all you californian guys a Mw5.7 must have given you gear a good > workout > > Dave _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Mike Stickney Subject: Re: Concrete foundations and DECOUPLING Date: Sun, 2 Nov 97 09:54:16 MST Albert: Seismic piers installed in the basements of buildings are typically constructed in the manner you describe. The concrete pier is poured on the material below building slab grade (hopefully bedrock). It projects up through the building floor with a surrounding 1-2 inch air gap such that the building floor never comes into direct contact with the sides of the pier. I don't know how much actual decoupling from activities in the building this method provides, but in my experience, it has not introduced any spurious effects. At the frequencies of interest to you, I doubt your seismic piers will give you problems. -Mike Stickney Earthquake Studies Office Montana Bureau of Mines and Geology Butte Montana http://mbmgsun.mtech.edu/ ====================================== At 08:01 PM 11/1/97 +0000, you wrote: >Hello, > I see from list of PSN sites that many have large concrete >blocks upon which the seismos are fixed. I too have a heavy >concrete block, 2ft long x 1.5 ft wide x 2ft DEEP. The block is >FLUSH with the ground surface, but ONLY the bottom 6 inches >of the block is in contact with the ground. (It is pinned into the >ground with 3/4 dia steel driven into earth at bottom last 6 inches). > > My reason for doing this was to decouple the block from any earth >movements at ground level.......footsteps, SMALL roots of hedges >and trees etc. > >I am now rather concerned that being situated on clay, then the >inertia of a 1/5th ton block will not allow it to move as the earth >beneath does. Should I 'fill in' the top 18 inches and ensure that >ALL the block is in direct contact with earth or not ?? Will the >block be decoupled and act as a cherry on top of jelly if I don't? > >If anyone with concrete blocks has considered above I would >like to know of their experiences, and what they did. Thanks. > > Regards, > > Albert Noble (England). > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Fish Lake Valley M5.3 aftershocks Date: Sun, 02 Nov 1997 10:33:49 -0700 A pretty good aftershock sequence is following the Fish Lake Valley, Nevada, M5.3 earthquake. I wish I could get away to go down there and feel 'em. It's only a 3 hr drive from my office. Rats! -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Taber Subject: re: Willmore seismometer Date: Mon, 3 Nov 1997 10:22:32 +1300 (NZDT) t 05:17 PM 11/2/97 +1200, you wrote: >hi all, > I have borrowed a Willmore MKI or II vertical seismometer for a >couple of months to try out. do any of you have practical experience in >using one of these beasts. Hi Dave, I just happen to have an old Willmore manual which I can copy and send to you if you are interested. I use the Willmore in a geophysics class lab where the students learn some of the basics about seismometers. Our Willmore has a 380 ohm coil, and critical damping (when there is no oscillation) is somewhere around 220 ohms. Typically the damping is set to 0.6-0.7 of critical damping. This is the point where the amplitude decreases by a factor of about 20 between successive half cycles, which seems to be a greater amount of damping than dropping to 1% after 3 cycles, as suggested by Al Allworth. John Taber School of Earth Sciences Victoria University of Wellington PS I get the PSN list as a daily digest so you should also email me directly if you want a quick response. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Robert L. Thomasson" <102073.3346@..............> Subject: Fish Lake Valley M5.3 aftershocks Date: Sun, 2 Nov 1997 16:42:27 -0500 Charles, <> Hmmm..I wonder if one could take on old 15" JBL studio monitor loudspeake= r and bolt it to the bottom of a chair and somehow couple the voice coil to= the seat and connect it to a computer audio output. You'd obviously als= o have to uncouple the chair seat from the floor. No scientific value that I can see, but it might be a great classroom demonstration to help get kids interested in seismology. The basic concept might have some merit, but if it does, I'm sure someone's already= done it. I'm right across the valley from you, out in the sage behind the NDF Fire= station on Mt Rose Hwy. I won't have my station up and running 'til at least spring, but it might be interesting to compare responses. = Regards, Bob _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Fish Lake Valley M5.3 aftershocks Date: Sun, 02 Nov 1997 15:22:40 -0700 Called Diane de Polo up at the UNR seismo lab. They had been fine tuning the new Earthwarm system this past week and Diane said she was watching the monitor rip off event after event then a big one then another and another... She has a trillion M1's! -- ---/---- Charles _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roseberry Subject: Geo-Monitor Date: Sun, 02 Nov 1997 18:12:23 -0600 Group: I am interested in acquiring all the past issues of Geo-Monitor, the earthquake prediction newsletter. Is there anyone out there who may have all or most of the past issues of this newsletter and would be interested in selling or giving :-) them to me? The former publisher offers most back issues -- but for a pretty hefty price -- so before I go that route I thought it might be prudent to inquire of the members of this list. I haven't seen many threads of discussion on the topic of earthquake prediction in the last year or so; there was considerable interest on this list about two years ago when I first tuned in. Anyone out there still winding coils and such? Or is it now considered a dead end? Michael J. Roseberry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: [Fwd: Press Release (fwd)] Date: Sun, 02 Nov 1997 17:20:12 -0700 FYI -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com ####################################################################### John G. Anderson Phone: (702) 784-4265 Seismological Laboratory / 174 FAX: (702) 784-1833 or 784-1766 University of Nevada jga@.............. Reno, Nevada 89557 ####################################################################### ---------- Forwarded message ---------- Date: Sun, 2 Nov 1997 15:22:23 -0800 (PST) From: John Anderson To: nveqfax@.................... Cc: Mackay all Subject: Press Release 2 November 1997 2:30 PM PDT Press Release Seismological Laboratory University of Nevada, Reno A magnitude 5.4 earthquake occurred at about 1 AM on November 2, 1997, in northern Fish Lake Valley, Nevada, about 60 miles west-southwest of Tonopah, Nevada. The preliminary location for the event determined by the University of Nevada Reno, Seismological Laboratory is; 37 Degrees 50.78 Minutes NORTH latitude, 118 Degrees, 12.86 Minutes WEST longitude. The preliminary depth estimate is 6 km (4 mi). This places the earthquake near the northern end of the Fish Lake Valley Fault Zone. The origin time of the earthquake is: November 2, 1997, 12:51 AM, Pacific Standard Time. The earthquake was preceded by a relatively strong foreshock (M=4.2) at 12:34 AM. The area had also become more active with very small earthquakes over the past week or so. Dirk Andrews, the Fire Chief for Fish Lake Valley, reported to the Seismological Laboratory that for the past week, rumbles were heard in the White Mountains - possibly an earthquake sound phenomenon caused by tiny shocks moving the surface of the ground like a loudspeaker. There is a strong aftershock sequence for todays earthquake. AT 1:00 PM, we were still recording over 100 small aftershocks per hour on our nearest station. The two largest aftershocks so far were at 7:02 AM (M=4.6) and 8:22 AM (M=4.2). Todays earthquake was in an area where earthquakes are to be expected. The Fish Lake Valley Fault Zone, and several other faults near the location of todays earthquake, are quite active from the geological viewpoint. The Eureka Valley earthquake, May 17, 1993, M=6.1, was about 50 miles southeast of todays earthquake. Todays earthquake is the largest event that has occurred in Nevada since the Double Spring Flat earthquake on September 12, 1994. That earthquake, magnitude 6.0, located 12 miles south-southeast of Gardnerville, was widely felt throughout the Reno-Carson City area. The Seismological Laboratory has received felt reports for todays earthquake from locations as far as Tonopah and Fallon, Nevada, and Fresno, California. The Seismological Laboratory has not received any reports of damage at this time. The data reported here is preliminary. For more information, contact the Seismological Laboratory at 702-784-4975, or http://www.seismo.unr.edu. The free pamphlet: "Earthquakes in Nevada and How to Survive Them" is available on request. ####################################################################### John G. Anderson Phone: (702) 784-4265 Seismological Laboratory / 174 FAX: (702) 784-1833 or 784-1766 University of Nevada jga@.............. Reno, Nevada 89557 ####################################################################### From: Stephen Caruso Subject: Earthwarm Project? Date: Sun, 2 Nov 1997 21:59:30 -0500 (EST) Sounds very interesting this earthwarm project. Is there a web site? 100's of M1's? STEPHEN CARUSO CET KB8UGH "Coincidence is a shortsighted mental delusion" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: re: Seismic radio monitoring Date: Sun, 02 Nov 1997 09:35:34 http://www.relisoft.com/freq.html , i >use on my dec alphas' (it also works on the x86 platform). As I am alway looking for something better I checked it out. A nice simple program but no record capability. A better program is fftdsp at http://www.webcom.com/~af9y/ the only problem is the program only runs one min then stops unless you register it. Not enough time to evaluate it. I know of a number of serious fold uning it and I have just registered it. It is a neat program and worth the 32 bucks. Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Cristiano Subject: Re: shake transducer Date: Sun, 02 Nov 1997 20:29:41 -0800 Robert L. Thomasson wrote: > > Charles, > > <> > > Hmmm..I wonder if one could take on old 15" JBL studio monitor loudspeaker > and bolt it to the bottom of a chair and somehow couple the voice coil to > the seat and connect it to a computer audio output. You'd obviously also > have to uncouple the chair seat from the floor. Since you mentioned it, Aura Systems makes floor shaker transducers for sound systems. It's ~ 5" dia. and bolts to the car body under the seats or to the floor and creates the subaudible "thump" you feel when the stereo is cranked up. Instead of the fixed magnet moving the coil and cone, as in a conventional dynamic speaker, the coil is fixed and the magnet (mass) moves. Bolt one of these to the table top and feed it the right frequency (or seismic signal) and stuff is going to walk right off the table. ( just in case someone wanted to bolt one to the bottom of a chair) Jim cristiano@........... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: New Ca map Date: Sun, 02 Nov 1997 20:31:28 -0700 Looks great Dave! Thanks.... -Larry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Walt Williams" Subject: Re: shake transducer Date: Sun, 2 Nov 1997 21:51:36 +0000 Hello, 2 pennies worth Four old mainframe hard disk transport voice coil assemblies mounted in the vertical axis could be used? Even has the attendant power amps and they are digital drive ultimately? If you are like me and have some old stuff laying about. Walt Williams, 97.11.02 dfheli@.............. http://www.pacificnet.net/~dfheli Woodland Hills, California USA ========================================== driver ------- Forwarded Message Follows ------- Date: Sun, 02 Nov 1997 20:29:41 -0800 From: Jim Cristiano Reply-to: PSN-L Mailing List Organization: weitech To: PSN-L Mailing List Subject: Re: shake transducer Robert L. Thomasson wrote: > > Charles, > > <> > > Hmmm..I wonder if one could take on old 15" JBL studio monitor loudspeaker > and bolt it to the bottom of a chair and somehow couple the voice coil to > the seat and connect it to a computer audio output. You'd obviously also > have to uncouple the chair seat from the floor. Since you mentioned it, Aura Systems makes floor shaker transducers for sound systems. It's ~ 5" dia. and bolts to the car body under the seats or to the floor and creates the subaudible "thump" you feel when the stereo is cranked up. Instead of the fixed magnet moving the coil and cone, as in a conventional dynamic speaker, the coil is fixed and the magnet (mass) moves. Bolt one of these to the table top and feed it the right frequency (or seismic signal) and stuff is going to walk right off the table. ( just in case someone wanted to bolt one to the bottom of a chair) Jim cristiano@........... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Major Solar Flare Alert Date: Wed, 05 Nov 1997 00:25:34 +1200 hi all, Early in the utc day on the 4th Nov. a large X-class proton flare eminated from Region 8100. It is the 1st x-class flare for the new solar cycle and the first for a number of years. It was preceeded by a M2 and a M4 flare. This region has been growing very quickly in complexity over the last 3 days and on the 3rd Nov. I counted 30 spots in the group. The huge outpouring of x-rays from this event caused a strong PCA (Polar Cap Absorption ) event that started between 0900 and 1030 UTC 4 Nov. My reception of 10MHz WWV went from very clear and stable to extremely distorted over that period. The protons from this event travel somewhat slower (~600 to 1000 km/sec) and are expected to arrive within the next 24 to 40 hours. Their arrival will herald the start of strong auroral storming and any of you with working magentometers should be able to record the impact with the Earth's geomagnetic field as it buckles under the stress. Keep your eyes on the sky nthrn hemisp. to the nth and the sthrn hemisp. to the sth (of course) pray for clear skies you guys in alaska, canada, new york state should get a great view. Cheers Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Major Solar Flare Alert; web site news Date: Tue, 04 Nov 1997 07:10:05 -0700 Read about the recent solar flare here: http://dxlc.com/solar/index.html Should be a wooper! -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Major Solar Flare Alert; web site news Date: Wed, 05 Nov 1997 08:12:09 +1200 The timing of the flare at this site seems to be 40 minutes late the "horses mouth " report stated 0558 UTC at this site you will find images of the sun in different wavelengths eg. x-ray, helium, iron, etc. http://umbra.gsfc.nasa.gov/images/latest.html the very bright region in the lower right corner of the sun is Region 8100 and this is where the activity is coming from Dave At 07:10 AM 11/4/97 -0700, you wrote: >Read about the recent solar flare here: >http://dxlc.com/solar/index.html> >Should be a wooper! >Charles P. Watson, Consulting Geologist Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: MLamb12830@....... Subject: Making rare earth magnets as good as alnico in signal output? Date: Tue, 4 Nov 1997 20:33:58 -0500 (EST) Hi group; I've noticed that here in Colorado, a number of electronic surplus stores have a variety of computer drive magnets. Most seem (its hard to always tell), to be the neodymium variety; with a sprinkling of older ferrous variety showing up. The neo variety are the most interesting due to their ~ 15k guass fields; although they are usually small and "wing" or "butterfly" shaped. For eddy current damping they are excellent in a "U" shaped iron/steel holder and are affixed to the inside upper part. The spacing must be close between the magnets. Regardless; for straight coil & magnet applications, it seems there is more of a signal (x5 - x10) from the older alnico magnets, which is presumably due to size/mass/broader flux field. Adding iron/steel helps space or broaden this guass field somewhat. I've tried afew varietys of magnet and iron designs but haven't found the right combinaton to make them approach even a small alnico in output signal from a coil. The question is,...........does anybody have a design or know of a WWW site, or reference to a book or magazine article that expounds on this "holy grail"? I'am probably missing the boat, or it left years ago; but it seems that the future supply of magnets for us may well be these critters, and making them much more useful. Thanks, Meredith _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: Making rare earth magnets as good as alnico in signal output? Date: Tue, 04 Nov 1997 18:37:10 -0800 One thing to understand about these magnets is that the "butterfly" or half moon shaped magnets are most likely surplus from use in voice coil motors (head positioners) in hard disk drives for computers. As such, the magnetization is such that as you view it, it has two poles on its surface -- a North and a South. The voice coil is pyramidal or wedge shaped and the two sloped sides of the wedge will lie in the middle of the poles. If you were to use a coil which encompasses the whole magnet, you will effectively cancel out the induced voltage. To get an equivalent magnet, break the magnet in half lengthwise, now you will have two single-pole magnets. I.e., -------------------------------- | N N N N N N N S S S S S S S | | N N N N N N N S S S S S S S | | N N N N N N N S S S S S S S | | N N N N N N N S S S S S S S | -------------------------------- ^ | +--- Break here There are some exceptions to the above. If there are two individual segments mounted on the iron keeper, then each segment is a single pole as you would expect. The other technique would be to make a coil whose diameter is basically equal to the pitch of the poles in the magnet and lay it on the face--as it moves sideways, it will be very effective in generating voltage. Charles R. Patton, Editor, Geo-Monitor patton@......... MLamb12830@....... wrote: .... > variety of computer drive magnets.... > although they are usually small and "wing" or "butterfly" shaped. > ...but haven't found the right > combinaton to make them approach even a small alnico in output signal from a > coil. ... > Thanks, Meredith > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Fontana Trend Date: Tue, 4 Nov 1997 19:31:34 -0800 (PST) Hello all: This morning there was another earthquake on what they consider to be the "Fontana Trend." It wasn't a huge earthquake, only 3.6 according to Caltech. However, it seems like every time another shock occurs it gets a little closer to the San Jacinto fault. This time it was less than 5 miles away. What does this tell us for the future? I have read the official publication about the proposed scenario for a major quake along this segment of the San Jacinto fault and it isn't pretty. Lots of infra-structure that could fail. Everything from major power grids to oil and gas pipelines that extend across the San Andreas just to the north of this location. It seems to me this area is a powder keg if and when it gets another big one. Between the Cucamonga, San Jacinto and the San Andreas faults this Fontana sequence gets on my nerves a little! Frank Condon mail to: frankcnd@.......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: MLamb12830@....... Subject: Making rare earth magnets as good as alnico in signal output. Date: Wed, 5 Nov 1997 01:41:59 -0500 (EST) Hi group, Thank you Charles Patton for your reply. So,....basically these are 4 pole magnets; 2 N & 2 S poles, or 2 magnets in one unit. Is monolithic, the right word; my dictionary is dated 1962, so I don't know for sure. I do have a coil which I think will "do", for the moment. Its an old 1950's ~ Texas Instrument Rectiwriter pen motor coil which is rectangular & of the same width as the magnets; however the length is much longer. Its about 1500 ohms, but I have no way to measure its gauge wire. Also have several of these neo magnets. As I don't want to break these units, (they oxidize), so I think I'll keep them intact and go from there. To make it short, I just tried using 2 intact neo magnets with a square iron spacer located on the bottom third of each magnet and separating the two magnets. Yes,...it is the old "U" shape and upright, with the coil going between the the center and one side of the "U". Yes,....indeed, it worked swell! The voltage was about 20% more (1.8v compared to alnico of 1.4v max). This was per an unscientific hand movement of the coil. With a tighter spacing of the magnets, (risky for the magnets & coil), the voltage may go higher. The area of the coil covered by the neo magnets is only about one sixth of the area covered by the alnico. The deeper depth of the arrangement, also allows for more coil movement. With a "W" arrangement; with the coil centered over the "W" assembly it maybe an even stronger generator. This is all & good for coils with space in the center to accomodate parts of the magnet/iron. I haven't tried coils that fit in between the magnets. Goodby alnico............ Thanks,................Meredith _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Al Allworth Subject: Re: Making rare earth magnets as good as alnico in signal Date: Tue, 4 Nov 1997 23:35:37 -0800 (PST) At 06:37 PM 11/4/97 -0800, you wrote: >One thing to understand about these magnets is that the "butterfly" or Hello All, I have a small head drive assembly from a 3 1/2" hard drive that I am thinking of trying as a seismometer by attaching a weight where the heads were and tilting a little to provide restoring action (a near horizontal pendulum). It should work as a stromg motion device. Any comments? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: MLamb12830@....... Subject: Making rare earth magnets as good as alnico in signal output? Date: Wed, 5 Nov 1997 03:25:24 -0500 (EST) Hi group; I've noticed that here in Colorado, a number of electronic surplus stores have a variety of computer drive magnets. Most seem (its hard to always tell), to be the neodymium variety; with a sprinkling of older ferrous variety showing up. The neo variety are the most interesting due to their ~ 15k guass fields; although they are usually small and "wing" or "butterfly" shaped. For eddy current damping they are excellent in a "U" shaped iron/steel holder and are affixed to the inside upper part. The spacing must be close between the magnets. Regardless; for straight coil & magnet applications, it seems there is more of a signal (x5 - x10) from the older alnico magnets, which is presumably due to size/mass/broader flux field. Adding iron/steel helps space or broaden this guass field somewhat. I've tried afew varietys of magnet and iron designs but haven't found the right combinaton to make them approach even a small alnico in output signal from a coil. The question is,...........does anybody have a design or know of a WWW site, or reference to a book or magazine article that expounds on this "holy grail"? I'am probably missing the boat, or it left years ago; but it seems that the future supply of magnets for us may well be these critters, and making them much more useful. Thanks, Meredith _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: GeE777@....... Subject: Fwd: ): MS announcement Date: Wed, 5 Nov 1997 07:46:51 -0500 (EST) In a message dated 97-11-04 20:35:45 EST, MLTCOLL writes: << Subject: MS announcement Microsoft Addresses Justice Department Accusations REDMOND, Wash. - Oct. 21, 1997 -- In direct response to accusations made by the Department of Justice, the Microsoft Corp. announced today that it will be acquiring the federal government of the United States of America for an undisclosed sum. It's actually a logical extension of our planned growth, said Microsoft chairman Bill Gates, It really is going to be a positive arrangement for everyone. Microsoft representatives held a briefing in the oval office of the White House with U.S. President Bill Clinton, and assured members of the press that changes will be minimal. The United States will be managed as a wholly owned division of Microsoft. An initial public offering is planned for July of next year, and the federal government is expected to be profitable by Q4 1999 at latest, according to Microsoft president Steve Ballmer. In a related announcement, Bill Clinton stated that he had willingly and enthusiastically accepted a position as a vice president with Microsoft, and will continue to manage the United States government, reporting directly to Bill Gates. When asked how it felt to give up the mantle of executive authority to Gates, Clinton smiled and referred to it as a relief. He went on to say that Gates has a proven track record, and that U.S. citizens should offer Gates their full support and confidence. Clinton will reportedly be earning several times the 200,000 annually he has earned as U.S. president, in his new role at Microsoft. Gates dismissed a suggestion that the U.S. Capitol be moved to Redmond as silly, though did say that he would make executive decisions for the U.S. government from his existing office at Microsoft headquarters. Gates went on to say that the House and Senate would of course be abolished. Microsoft isn't a democracy, he observed, and look how well we're doing. When asked if the rumored attendant acquisition of Canada was proceeding, Gates said, We don't deny that discussions are taking place. Microsoft representatives closed the conference by stating that United States citizens will be able to expect lower taxes, increases in government services and discounts on all Microsoft products. About Microsoft Founded in 1975, Microsoft (NASDAQ MSFT) is the worldwide leader in software for personal computers, and democratic government. The company offers a wide range of products and services for public, business and personal use, each designed with the mission of making it easier and more enjoyable for people to take advantage of the full power of personal computing and free society every day. About the United States Founded in 1789, the United States of America is the most successful nation in the history of the world, and has been a beacon of democracy and opportunity for over 200 years. Headquartered in Washington, D.C., the United States is a wholly owned subsidiary of Microsoft Corporation. The United States of America and Microsoft are registered trade marks of Microsoft Corporation. >> --------------------- Forwarded message: Subj: Fwd: ): MS announcement Date: 97-11-04 20:35:45 EST From: MLTCOLL To: HELDHI@....................... To: DANSIMPSN,PGJONES@........... To: JMAY@............................ To: Dactyle,RROCKWEL@................. To: glats2cu@........ To: jerald@............. --------------------- Forwarded message: Subj: Fwd: ): MS announcement Date: 97-11-04 17:42:35 EST From: JackCeram To: BBUTEK,Airplayn@............. To: Negrych@...................... To: BillPayne,Silbond@................ To: JReents@........ To: KGaughan@............... To: ASalamat@......................... To: MVRUBIN,102421.3464@.............. To: SFisher@............ To: Stratton_Tom@....................... To: Gnels,J3L1Ferr@....... To: bobeangi@..................... To: LAMemm@.......................... To: MLTCOLL,GWimsatt@............ To: DrDave.Norris@........ To: Pelican@....................... To: WS-FELS@........... --------------------- Forwarded message: From: gdula@.......... (Bob Gdula) To: stella1@.......... (Stella Gdula), "Jackceram@......."@.......... Date: 97-11-03 12:27:00 EST Robert A. Gdula , Ph.D. Interface and Surface Science Materials Laboratory IBM Storage Systems Division San Jose, CA USA (408) 256-0316 e-mail internal: Bob Gdula/San Jose/IBM@IBMUS internet: gdula@.......... ---------------------- Forwarded by Bob Gdula/San Jose/IBM on 11-03-97 09:16 AM --------------------------- Alan Spool 11-03-97 08:43 AM To: sjevm5.ghaderi@vm, sjevm5.prime@vm, sjevm5.byork@vm, almvma.legg@vm, sjevm5.mparker@vm, Catherine E Albrecht/San Jose/IBM@IBMUS, Malika Carter/San Jose/IBM@IBMUS, Joel Forrest/San Jose/IBM@IBMUS, Mariano Garces/San Jose/IBM@IBMUS, Charles Hignite/San Jose/IBM@IBMUS, William S Morrison/San Jose/IBM@IBMUS, Phil Peterson/San Jose/IBM@IBMUS, Dennis Ramos/San Jose/IBM@IBMUS, Alan Spool/San Jose/IBM@IBMUS, Regina Strener/San Jose/IBM@IBMUS, Gloria Washington/San Jose/IBM@IBMUS, Gina Whitney/San Jose/IBM@IBMUS, Kathy Kuboi/San Jose/IBM@IBMUS, Deborah Yaney/San Jose/IBM@IBMUS, Ron Herbold/San Jose/IBM@IBMUS, John Burns/San Jose/IBM@IBMUS, Cynthia Delenia/San Jose/IBM@IBMUS, Thomas Blackburn/San Jose/IBM@IBMUS, Daryl Pocker/San Jose/IBM@IBMUS, Mike Baldwin/San Jose/IBM@IBMUS, Elizabeth Brinkman/San Jose/IBM@IBMUS, Joel Caharian/San Jose/IBM@IBMUS, Wendy Chung/San Jose/IBM@IBMUS, Bob Gdula/San Jose/IBM@IBMUS, Katherine Ledesma/San Jose/IBM@IBMUS, Heidi Merkins/San Jose/IBM@IBMUS, Renata Vedder/San Jose/IBM@IBMUS, Joel Lai/San Jose/IBM@IBMUS, Garvin Stone/San Jose/IBM@IBMUS, Monica Vargas/San Jose/IBM@IBMUS, Richard Stover/San Jose/IBM@IBMUS, Frederick Eng/San Jose/IBM@IBMUS, Mark Powell/San Jose/IBM@IBMUS, Thomas Shatz/San Jose/IBM@IBMUS, Jane Kraus/San Jose/IBM@IBMUS, David Scott/San Jose/IBM@IBMUS, Owen Melroy/Almaden/IBM@ALMADEN @ IBM_INTERNAL cc: Subject: ): MS announcement FYI ---------------------- Forwarded by Alan Spool/San Jose/IBM on 11/03/97 08:42 AM --------------------------- guppymom@........ on 10/31/97 08:26:10 PM Please respond to guppymom@........ @ internet To: plant1.pcnet.net.com!ke3147@........... @ internet, Nsmereski@....... @ internet, Imthetaxmn@....... @ internet, Alan Spool/San Jose/IBM@IBMUS, Beutboni@........... @ internet, wsattler@........... @ internet, joe_mckeon@.......... @ internet, Mike_mcintyre@.......... @ internet, Tak843@....... @ internet, L82school@........ @ internet, pkipnis@............. @ internet, askal@........ @ internet, Otto_hovorka@.................... @ internet, mgustafson@........... @ internet, burt_gustaf@....... @ internet, elaine_chung@........... @ internet, brionese@.............. @ internet cc: Subject: ): MS announcement Subject: MS announcement Microsoft Addresses Justice Department Accusations REDMOND, Wash. - Oct. 21, 1997 -- In direct response to accusations made by the Department of Justice, the Microsoft Corp. announced today that it will be acquiring the federal government of the United States of America for an undisclosed sum. It's actually a logical extension of our planned growth, said Microsoft chairman Bill Gates, It really is going to be a positive arrangement for everyone. Microsoft representatives held a briefing in the oval office of the White House with U.S. President Bill Clinton, and assured members of the press that changes will be minimal. The United States will be managed as a wholly owned division of Microsoft. An initial public offering is planned for July of next year, and the federal government is expected to be profitable by Q4 1999 at latest, according to Microsoft president Steve Ballmer. In a related announcement, Bill Clinton stated that he had willingly and enthusiastically accepted a position as a vice president with Microsoft, and will continue to manage the United States government, reporting directly to Bill Gates. When asked how it felt to give up the mantle of executive authority to Gates, Clinton smiled and referred to it as a relief. He went on to say that Gates has a proven track record, and that U.S. citizens should offer Gates their full support and confidence. Clinton will reportedly be earning several times the 200,000 annually he has earned as U.S. president, in his new role at Microsoft. Gates dismissed a suggestion that the U.S. Capitol be moved to Redmond as silly, though did say that he would make executive decisions for the U.S. government from his existing office at Microsoft headquarters. Gates went on to say that the House and Senate would of course be abolished. Microsoft isn't a democracy, he observed, and look how well we're doing. When asked if the rumored attendant acquisition of Canada was proceeding, Gates said, We don't deny that discussions are taking place. Microsoft representatives closed the conference by stating that United States citizens will be able to expect lower taxes, increases in government services and discounts on all Microsoft products. About Microsoft Founded in 1975, Microsoft (NASDAQ MSFT) is the worldwide leader in software for personal computers, and democratic government. The company offers a wide range of products and services for public, business and personal use, each designed with the mission of making it easier and more enjoyable for people to take advantage of the full power of personal computing and free society every day. About the United States Founded in 1789, the United States of America is the most successful nation in the history of the world, and has been a beacon of democracy and opportunity for over 200 years. Headquartered in Washington, D.C., the United States is a wholly owned subsidiary of Microsoft Corporation. The United States of America and Microsoft are registered trade marks of Microsoft Corporation. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roseberry Subject: Re: Making rare earth magnets as good as alnico in signal output? Date: Wed, 05 Nov 1997 09:20:42 -0600 Charles R. Patton wrote: > ... break the magnet in half lengthwise, now you will > have two single-pole magnets. I.e., > > -------------------------------- > | N N N N N N N S S S S S S S | > | N N N N N N N S S S S S S S | > | N N N N N N N S S S S S S S | > | N N N N N N N S S S S S S S | > -------------------------------- > ^ > | > +--- Break here > Mr. Patton: I'm puzzled. Are you suggesting that when a bar magnet is divided, one piece becomes a "South" monopole; the other a "North" monopole? If so, that would undermine almost everything I have come to understand about magnets, in particular, their internal structure. Regards, Michael J. Roseberry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: Making rare earth magnets as good as alnico in signal output? Date: Wed, 5 Nov 1997 09:38:23 -0600 I don't think that is what he meant. It is hard to communicate some of these things without good pictures. With the magnets in question the opposite pole is on the back side of the magnet. So when you break it instead of having a magnet with 4 poles you get two magnets with two poles. Jim Hannon mjr@........ on 11/05/97 09:20:42 AM Please respond to psn-l@............. To: psn-l@............. cc: (bcc: James M Hannon/CedarRapids/Collins/Rockwell) Subject: Re: Making rare earth magnets as good as alnico in signal output? Charles R. Patton wrote: > ... break the magnet in half lengthwise, now you will > have two single-pole magnets. I.e., > > -------------------------------- > | N N N N N N N S S S S S S S | > | N N N N N N N S S S S S S S | > | N N N N N N N S S S S S S S | > | N N N N N N N S S S S S S S | > -------------------------------- > ^ > | > +--- Break here > Mr. Patton: I'm puzzled. Are you suggesting that when a bar magnet is divided, one piece becomes a "South" monopole; the other a "North" monopole? If so, that would undermine almost everything I have come to understand about magnets, in particular, their internal structure. Regards, Michael J. Roseberry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: GeE777@....... Subject: Re: Fontana Trend Date: Wed, 5 Nov 1997 11:35:09 -0500 (EST) In a message dated 97-11-05 01:46:29 EST, frankcnd@.......... writes: << This morning there was another earthquake on what they consider to be the "Fontana Trend." It wasn't a huge earthquake, only 3.6 according to Caltech. >> Please note the map in- http://quake.wr.usgs.gov/recenteqs/ as of this date. There is a series of small events circumventing the ''locked area'' of the San Andreas Fault to the northeast. These series of small events leave the area of the San Andreas Fault in the Fontana area and return to the San Andreas in the Parkfield area. George Erich GeE777@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Bone Subject: Re: Fontana Trend Date: Wed, 05 Nov 1997 14:49:23 -0800 GeE777@....... wrote: > > In a message dated 97-11-05 01:46:29 EST, frankcnd@.......... writes: > > << This morning there was another earthquake on what they consider to be the > "Fontana Trend." It wasn't a huge earthquake, only 3.6 according to Caltech. > >> > > Please note the map in- > http://quake.wr.usgs.gov/recenteqs/ > > as of this date. > > There is a series of small events circumventing the ''locked area'' of the > San Andreas Fault to the northeast. These series of small events leave the > area of the San Andreas Fault in the Fontana area and return to the San > Andreas in the Parkfield area. > > George Erich > GeE777@....... > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L Could you be more specific?? A list of point might be helpful in visualizing the trend you are describing. Thanks in advance. Jim Bone _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: lahr@................. (Dr. John Lahr (USGS-GI Seismologist)) Subject: seismometers need good home Date: Wed, 5 Nov 1997 17:27:59 -0900 Hi John, I wonder if the Smithsonian would be interested in these instruments? JCLahr ################################## John C. Lahr ################################# Seismologist ################################ U.S. Geological Survey ############################### Geologic Hazards Team ############################## 1711 Illinois Street ~~~~~~~~~~~~~~ Get ~~~~~~~~~~ ############################# ########################################################### Golden, Colorado 80401 ################################ Phone: (303) 273-8596 ################################# Fax: (303) 273-8600 ~~~~~~~~ the thrust? ~~~~~~~~~~~~~ lahr@........ #################################### http://www.aeic.alaska.edu/lahr > From bulkmail@................... Wed Nov 5 16:12:41 1997 > Date: Wed, 5 Nov 97 17:15:59 PST > From: Bulkmail System > Subject: WWSSN Seismometers Available > > WWSSN Seismometers Available > > I would like these instruments to get a good home where, ideally, they can > be set up and used to record earthquakes as they were intended to be used. > > These are examples of the original Sprengnether WWSSN seismometers > which collected much of the original seismological data that led to the > acceptance of plate tectonics. As such they have some historical value. > > These, however, are working instruments. They require a rather large area > to set up and moderate-to-good temperature control to operate reliably. > Thus they are not suitable as "field" instruments. Probably, some university > that is looking to get a station operating for research and teaching is the > ideal candidate to gets these instruments. > > I will be glad to help get them to who ever can use them. I have limited > knowledge of setting them up, but have a set of manuals. The gaining > institution will have to pay shipping charges, which should be minor. The > instruments are large in volume, but not particularly heavy. > > These instruments are on loan from the USGS to the Air Force. I have the > USGS-to-AF transfer paperwork, so the "title" is clear. > > My address is: > > John Cipar > Air Force Research Laboratory > Hanscom AFB, MA > 617-377-3767 > cipar@.......... > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: seismometers need good home Date: Thu, 06 Nov 1997 16:13:30 +1200 John, these are an awesome seismometer and ther do weigh a lot ~30+ lbs for someone who doesn't want to build a LP lehman this would be an excellect choice I have one here at home that will be uop and unning as soon as the concrete pad can be laid and styrofoam housing organised. The Sprengnether or Press-Ewing, as it was originally known as has an adjustable period from ~12 to 45 seconds (up to 60 sec if you can place it in a very low noise site and keep the temperature very stable. Dave At 05:27 PM 11/5/97 -0900, you wrote: >Hi John, >I wonder if the Smithsonian would be interested in these instruments? >JCLahr >> Date: Wed, 5 Nov 97 17:15:59 PST >> From: Bulkmail System >> Subject: WWSSN Seismometers Available >> WWSSN Seismometers Available >> I would like these instruments to get a good home where, ideally, they can >> be set up and used to record earthquakes as they were intended to be used. >> These are examples of the original Sprengnether WWSSN seismometers >> which collected much of the original seismological data that led to the >> acceptance of plate tectonics. As such they have some historical value. >> These, however, are working instruments. They require a rather large area >> to set up and moderate-to-good temperature control to operate reliably. >> Thus they are not suitable as "field" instruments. Probably, some university >> that is looking to get a station operating for research and teaching is the >> ideal candidate to gets these instruments. >> I will be glad to help get them to who ever can use them. I have limited >> knowledge of setting them up, but have a set of manuals. The gaining >> institution will have to pay shipping charges, which should be minor. The >> instruments are large in volume, but not particularly heavy. >> >> These instruments are on loan from the USGS to the Air Force. I have the >> USGS-to-AF transfer paperwork, so the "title" is clear. >> >> My address is: >> >> John Cipar >> Air Force Research Laboratory >> Hanscom AFB, MA >> 617-377-3767 >> cipar@.......... >> > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: owl@................. Subject: Is Your Web Site A Secret? Date: Wed, 5 Nov 1997 23:13:32 -0500 (EST) Is your web site the best kept secret on the Internet? We'll promote it to 50 search engines and indexes for $85 and complete the job in 2 business days. Satisfaction is guaranteed! If you have a great product, but are not getting many inquiries from your Web site, you may not be adequately listed on the Web's search engines and indexes. Millions of viewers daily use these facilities to find the products and services they are looking for. But if your site is not listed, no one will see it. Listings on most of these services are free. However, locating and filling out the forms required to get a listing can take several days, and most people just don't have the time to do it. That is why we offer a web site promotion service. WHAT'S THE DEAL? We will submit your site to 50 indexes and search engines for $85. We will accept the return of this E-mail, with the form below filled out, as an order. We will bill you upon completion of the promotion. Our terms are net 15 days from date of invoice. Satisfaction guaranteed! HOW LONG WILL IT TAKE? Generally, we complete the submissions within 48 hours of receiving your order. It can take any individual search engine or index up to three weeks to process your submission, although most are much faster. WHAT SEARCH ENGINES AND INDEXES ARE INCLUDED IN THE PROMOTION? The list changes from time to time. This is our current list: Alta Vista, BC Internet, BizCardz Business Directory, BizWeb, Excite, Galaxy, HotBot, Infoseek, InfoSpace, Jayde Online Directory, JumpCity JumpLink, Linkcentre Directory, LinkMonster, Lycos, Magellan, Manufacturers Information Network, Net Happenings, Net Mall, Net-Announce, New Page List, New Riders WWW Yellow Pages, Northern Light, One World Plaza, Open Text Web Index, PageHost A-Z, PeekABoo, Project Cool, Scrub The Web, Seven Wonders, Sserv, Starting Point, The Galactic Galaxy, The Weekly Bookmark, True North,TurnPike, Unlock:The Information Exchange, Web 100, Web Crawler, Web Walker, Web World Internet Directory, WebVenture Hotlist, What's New, WhatUSeek, Where2Go, World Wide Business Yellow Pages, Wow! Web Wonders!, WWW Worm, YelloWWWeb, Your WebScout HOW WILL I KNOW THAT YOU HAVE PROMOTED MY SITE? When we have completed the promotion, we will send you an HTML file as an attachment to your E-mail bill. Save this file to your disk, and view it through your Web browser. It provides links to the search engine we submitted your site to, plus any comments we received from them when we did it. ARE THERE ANY GUARANTEES? We do not require prepayment. Your satisfaction is guaranteed or you don't pay the bill. WHO IS OWL'S EYE PRODUCTIONS? We are a web site promotion company located at: Owl's Eye Productions, Inc. 260 E. Main Street Brewster, NY 10509 Phone: (914) 278-4933 Fax: (914) 278-4507 Email: owl@................. HOW DO I ORDER? The easiest way to order is by e-mail. Just hit the REPLY button on your e-mail program and fill out the following information. (This information will be posted to the search engines/indexes): Your name: Company Name: Address: City: State/Prov: Zip/Postal Code: Telephone: Fax: Email address: URL: http:// Site Title: Description (about 25 words): Key words (maximum of 25, in descending order of importance): Proofs (Where shall we e-mail proofs): If billing a different address, please complete the following: Addressee: Company Name: Address: City: State/Prov: Zip/Postal Code: Telephone: Fax: Email address: We will bill via Email. (SE7O22) Terms: By returning this document via Email, you agree as follows: You have the authority to purchase this service on behalf of your company. Terms are net 15 days. Accounts sent to collections will be liable for collection costs. You agree to protect and indemnify Owl's Eye Productions, Inc. in any claim for libel, copyright violations, plagiarism, or privacy and other suits or claims based on the content or subject matter of your site. WHAT HAPPENS NEXT? When we receive your order, we will input the information into our system, and send you a proof. After we process any corrections, we will run your promotion, capturing any comments from search engines as we go. We will incorporate these into an HTML-formatted report to you, which we will attach to your bill. ===Web Promotions=====Press Releases=====Link Exchanges========= Owl's Eye Productions, Inc. 260 E. Main Street Brewster, NY 10509 Ph: 914-278-4933 Fx: 914-278-4507 E-mail: owlseye@................. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Mark Wilson mark@.............." Subject: Re: Is Your Web Site A Secret? Date: Wed, 5 Nov 1997 20:48:43 -0800 (PST) Doesn't this stuff just irritate you to no end? *********************************************************************** --- mark@.............. --- http://www.markwilson.com --- wilsonm@............ *********************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: seismometers need good home Date: Thu, 06 Nov 1997 14:42:39 +0000 David A. Nelson wrote: > these are an awesome seismometer and ther do weigh a lot ~30+ lbs... .....snip..... Hi Dave, Many years ago, before we were both born (!), the moving mass of seismometers could weigh over 20 TON!!.....the 'Wiechert' monster in Europe was such a beastie. It used mechanical levers, coupled from the 20 ton mass, to the pen and gave a magnification of some 2000! Regards, Albert Noble (England). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Larry P. Thomas WA0GWA" Subject: Re: Is ... Secret? What's a person to do! Date: Thu, 06 Nov 1997 08:53:00 -0600 >Doesn't this stuff just irritate you to no end? > >*********************************************************************** > --- mark@.............. > --- http://www.markwilson.com > --- wilsonm@............ >*********************************************************************** Sure does. I get it on every SIG I follow but there seems to be no real way of stopping it. I just keep hitting the "Delete" key. I ususally don't even comment on any of it. Some of the SIG's I follow are extremely sensitive (i.e. have a lot really rude people on them) and even simple comments start never ending threads. This PSN SIG is the best SIG I follow when it comes to tolerance. Wish all the SIG's I followed were as good as this one. Thanks Larry wa0gwa ----------------------------------------------------------------------- Larry P. Thomas wa0gwa voice : 1 913 888-0282 Krell Technologies fax : 1 913 782-9359 8960 Bond pager : 1 816 989-HELP Overland Park, KS www : http://www.krell.com 66214-1764 e-mail : mailto://lpthomas@................ ----------------------------------------------------------------------- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Marnie Gannon Subject: Canadian quake Date: Thu, 06 Nov 1997 11:44:06 -0700 You can find reports, locations and waveforms for the Canadian quake at: http://www.seismo.nrcan.gc.ca/eq_report.html Interestingly, there was a 4.7 in the area on Oct.28. Good site, with history of larger quakes: "Charlevoix - Kamouraska (CHV) an area 100km downriver from Quebec City. This is the most seismically active and most closely monitored region in eastern Canada. In 1925 an earthquake believed to be M7 occurred in the St. Lawrence valley near La Malbaie. This event caused extensive damage, particularly to communities along the banks of the river. Historical accounts describe the effects of three other earthquakes greater than M6 that occurred in this zone (1663, 1860 and 1870)." Marnie Gannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Lehman coil and magnet Date: Thu, 6 Nov 1997 14:43:40 -0600 The recent discussion of using hard drive magnets generated a question in my mind. Has anyone thought of or tried using a current input preamp rather than a voltage input preamp for the coil? In theory this should allow the use of a coil with fewer turns and still get the same level or larger out of the preamp. Having a coil with fewer turns would in turn make it easier to use the smaller magnets and a narrower gap which would also increase the output. Jim Hannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: GeE777@....... Subject: Eastern Sierra Nevada Quakes Date: Thu, 6 Nov 1997 16:56:27 -0500 (EST) Los Angeles Times, Nov 6, 1997 By Kenneth Reich NEXT STORY This week's moderately strong temblors in western Nevada could be=20 connected to a quake swarm about 30 miles away east of Mammoth Lakes,=20 scientists monitoring volcanic earthquakes near Mammoth said Wednesday.=20 =A0=A0=A0=A0=A0The U.S. Geological Survey reported 34 quakes of magnitude= 3.0 or=20 greater in California and Nevada this past week--an unusually high=20 number--including 24 in Nevada and five at Mammoth Lakes.=20 =A0=A0=A0=A0=A0Other quakes of this magnitude have occurred in such widel= y=20 separate areas as San Clemente Island and near Quincy in Northern=20 California. The latter quake, which occurred at 9:49 a.m. Wednesday, was=20 felt as far away as Sacramento. It was first measured at magnitude 4.8=20 but was later downgraded to 4.3. A 4.5 quake also occurred Wednesday=20 afternoon 30 miles southeast of Bishop, Calif.=20 =A0=A0=A0=A0=A0The seismic events in Nevada included quakes of magnitudes= 5.3,=20 4.8, 4.3 and 4.2 in a remote mountainous area.=20 =A0=A0=A0=A0=A0Hundreds of smaller quakes--the strongest was 3.4--have oc= curred=20 along the same northeast-southwest lineal alignment near the eastern=20 Sierra town of Mammoth Lakes.=20 =A0=A0=A0=A0=A0Scientists said there is no connection between the San Cle= mente=20 Island quake and the Quincy quake. But they viewed the Mammoth and=20 Nevada quakes differently.=20 =A0=A0=A0=A0=A0David Hill of the Geological Survey, the chief monitor of = volcanic=20 precursors in the Mammoth region, said that scientific monitoring of=20 Mammoth has increased since June in the wake of repeated swarms of=20 quakes, some increased ground uplift and small changes in hot springs.=20 =A0=A0=A0=A0=A0"We are certainly watching things more closely now," Hill = said.=20 "But . . . there is no evidence that things are moving toward [an=20 eruption in the short term]."=20 =A0=A0=A0=A0=A0Hill said that research into "sympathetic" earthquakes in = the=20 eastern Sierra after the comparatively distant Landers quake of 1992=20 could mean there is a possible connection between the Nevada and Mammoth=20 quakes.=20 =A0=A0=A0=A0=A0Ross Stein, another Geological Survey scientist, said, "Ma= mmoth is=20 basically straining the whole area, and quakes that have taken place=20 north of Bishop in the Chalfant Valley and in Nevada over the last 15 to=20 20 years could be related."=20 =A0=A0=A0=A0=A0He added: "This week the San Andreas fault [closer to the = Pacific]=20 seems to be sleeping, and what is known as the Eastern California Shear=20 Zone has been active. In that respect, he said, even the Quincy quake=20 [which is along the shear zone] could be connected to Mammoth."=20 =A0=A0=A0=A0=A0Allan Lindh, a former director of Geological Survey earthq= uake=20 research for the Western states, said, "We know from what happened after=20 Landers that there are long-distance connections between quakes.=20 =A0=A0=A0=A0=A0"The Nevada quakes in the Great Basin are related to volca= nic=20 processes," he said. "Probably all of this is related, we just don't=20 know exactly how."=20 =A0=A0=A0=A0=A0Chris Farrar, another monitor of Mammoth, said he believes= =20 scientific concern about a Mammoth eruption would rise "if the=20 deformation keeps going on at its current rate and moves into a=20 shallower depth."=20 =A0=A0=A0=A0=A0But Hill said: "We don't see any short-term, localized def= ormation=20 that might be associated with magma [molten rock] moving into the=20 shallower crust."=20 =A0=A0=A0=A0=A0Hill, Farrar and another survey specialist, Michael Sorey,= said=20 they have looked intensively into reports of recent changes in hot=20 springs near Mammoth. But they have not been able to establish any=20 overall increase in hot water emissions, which could be caused by=20 injections of magma into the ground water system.=20 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roseberry Subject: X9 Flare and Proton Event Date: Thu, 06 Nov 1997 19:51:48 -0600 Group: I realize this is a little off-subject. Possibly some of you have magnetometers (search coils were a subject of interest on this list last year), well if you do get ready! Our sun emitted a REALLY hugh flare this morning (see attachment); the next few days should be interesting for mag field watchers. Hope this info is not unwelcome on the list, if so, let me know. Regards, Michael J. Roseberry Hi Ron, Hal (New Millenium) has okayed my posting this....a new flare this morning. Regards, Nancy Hugo ---------- Forwarded message ---------- Date: Thu, 06 Nov 1997 11:18:03 -0500 From: New Millennium Subject: **X9 Flare and Proton Event** 11.06.97/1530 UTC X9 Flare and Proton Event 11.06.97 1530 UTC Wow! At approximately 1200 UTC (7am EST) this morning an ~X-9~ class flare was recorded by the solar measuring equipment used by NASA and SEC. Within 30 minutes an intense Proton flare event began at the GOES satellites as well. The massive flare that occurred on the 4th and has brought all the watches and anticipated magnetic storming (Nov 6-7-8) was an X-1 class flare. This mornings flare was an X-9, the ~very~ highest rating on the intensity scale for measuring the power output of solar flares. Just as the Xray signature of this new flare was much more powerful than Nov.4th's event, so was the Proton event that has followed. This is a difficult concept to grasp, but the energy released from this morning's X-9 flare was 100 million times more than with Tuesday's X-1 flare. Each number on the flare scale represents a tenfold increase in energy output of the event; As an example, an X-2 is ten times more powerful than an X-1. If the alignment of the event was "geoeffective" (in good position relative to Earth) then we can expect a truly massive electron cloud and geomagnetic event sometime between the 8th and the 10th. According to NASA, the famous geomagnetic storm of 1989 came after a series of flares-the most powerful of which was an X-5; Obviously this event has the ~potential~ to be much much more powerful. Today is the first day of the original series of magnetic storm watches. Obviously there will be a new series of severe magnetic storm watches issued for the 8th through the 10th... longer if the solar events continue. As soon as more detailed information is available on this morning's incredible event, I will send it out via email bulletins. From: Al Allworth Subject: Potential Geomagnetic Storm Warning Date: Thu, 6 Nov 1997 18:03:10 -0800 (PST) >X-Sender: caschue@...................... >Date: Thu, 06 Nov 1997 12:25:31 -0500 >To: Al - W7PXX , > Ed Bathgate RMA Repair Dept , > Bruce Erkkila-KC5OV , > Bruce Erkkila-KC5OV , > Don Hillger , > John K 5 J J , > "Jerry L. Rowe" , > Gary Shay , > Gary Barr-WA6TWT , > Richard Barth-W3HWN , > Dan Bathker , > Don Bennett-N7TF , > Shayla Taylor-KA5PRZ , > Felipe Arroyo , > Dick Foster , Bob Foster , > Muse Mann , > David Maples-WB4FUR , > Bill Notley-KD6ZXI , > Paul Robbins-KC6ZLW, > Steve Schindler-WD4MJJ, > "W. Russell Slye" , > Steve Veader , W6VPH , > H F WRIGHT , > Ron Grandmaison , > N V Pollack-KA3ENO , > Fred Fredlock-N4KVN , > Michael Cauley , > Marv Storey , > Steve Wnuk , > AA1BU , > AA2NN , K4VV , > K9ICF , > KC1SE , > KE7UA , N1OJ0 , > W1TCF , > W8XO , > WG3A , WN3X , > WX2S , > "Robert A. Kile-KG7D" , > EDMOND BRADY , > Zeke , > , , > Albert H Zimmerman-W8UYN , > "Paul J. Poling-N8CKG" >From: henry schuett >Subject: Potential Geomagnetic Storm Warning >Cc: Roberto.J.Acosta@.............. Godfrey.Anzic@.............. > Terry.L.Bell@.............. Joseph.M.Berki@.............. > Bruce.L.Bream@.............. Michael.A.Cauley@.............. > Donald.E.Costello@.............. William.T.Dedula@.............. > Douglas.C.Dolch@.............. Alan.N.Downey@.............. > Patrick.W.Dunn@.............. Michael.W.Goin@.............. > Raiford.E.Hann@.............. Don.R.Hilderman@.............. > Thomas.J.Hill@.............. Louis.R.Ignaczak@.............. > Kenneth.A.Jensen@.............. Brad.W.Kaustinen@.............. > David R Kifer , > Ihor.Kramarchuk@.............. Steven.W.Mainger@.............. > Joseph.Maziarz@.............. James.H.McKim@.............. > Robert.C.Mate@.............. Steven.W.ODonnell@.............. > Richard.L.Patterson@.............. William.J.Rieke@.............. > Michael.A.Robertson@.............. Noel.B.Sargent@.............. > Richard.R.Scheske@.............. Philip.A.Stehno@.............. > Russell.E.Steinbach@.............. William.H.Stokes@.............. > Steven.J.Struharik@.............. Daniel.M.Vento@.............. > Lawrence.W.Wald@.............. > KC8F , > Stephen.P.Wnuk@.............. 71026.1561@............... > Glenn L Williams , > kc4iyd@....................... > Nancy Rabel Hall , > Greg Romaniak-N8XOS, > Earl-N7BYL > >Subject: Potential Geomagnetic Storm Warning >>Date: Wed, 5 Nov 1997 13:31:01 -0500 >> >> >>Potential Geomagnetic Storm Warning >> >> (See Appended Comments for Synoptic Information) >> >> HIGH RISK PERIOD: 06 - 07 NOV (UT days) >>MODERATE RISK PERIOD: 05 - 08 NOV >> >> >>POTENTIAL LOW-MIDDLE LATITUDE STORM INTENSITY: MAJOR >> POTENTIAL HIGH LATITUDE STORM INTENSITY: MAJOR TO SEVERE >> >> >> POTENTIAL DURATION OF GEOMAGNETIC STORM: APPROX 48 HOURS >> DURATION OF MAIN BELT OF ACTIVITY: APPROX 24 HOURS ON 07 >>NOV >> >> >>POTENTIAL PEAK LOW-MIDDLE LATITUDE K-INDEX VALUES: 8 >> POTENTIAL PEAK HIGH LATITUDE K-INDEX VALUES: 9 >> >> >> EXPECTED DOMINATING LOW-MIDDLE LATITUDE K-INDEX: 5 TO 6 >> EXPECTED DOMINATING HIGH LATITUDE K-INDEX: 6 >> >> >> POTENTIAL FOR LOW LATITUDE HF DEGRADATION: MODERATE >> POTENTIAL SEVERITY OF HF DEGRADATION: STRONG MINOR >> EXPECTED HF PROPAGATION CONDITIONS: FAIR >> >> >>POTENTIAL FOR MIDDLE LATITUDE HF DEGRADATION: VERY HIGH >> POTENTIAL SEVERITY OF HF DEGRADATION: MAJOR >> EXPECTED HF PROPAGATION CONDITIONS: POOR TO USELESS >> >> >> POTENTIAL FOR HIGH LATITUDE HF DEGRADATION: VERY HIGH >> POTENTIAL SEVERITY OF HF DEGRADATION: MAJOR >> EXPECTED HF PROPAGATION CONDITIONS: VERY POOR TO FREQ. >>USELESS >> >> >>POTENTIAL RISK FOR GEOSYNCHRONOUS MAGNETOPAUSE CROSSINGS: 60PROBABLE >> >> >>SUSPECTED SOURCE OF OBSERVED/EXPECTED ACTIVITY: >>A series of coronal mass ejections. The last one observed on 04 >>November >>that was associated with the major X-class proton flare is expected to >>produce a major to severe geomagnetic storm on 07 November. >> >> >>--------------------------------- >>--------------------------------- >>EST. POTENTIAL GEOMAGNETIC IMPACT EST. POTENTIAL IONOSPHERIC >>IMPACT >>--------------------------------- >>--------------------------------- >> SEVERE STORM : 25 LOW LATITUDES : STRONG MINOR >> MAJOR STORM : 40 MIDDLE LATITUDES : MAJOR >> MINOR STORM : 30 HIGH LATITUDES : MAJOR >> ACTIVE OR LESS : 05 POLAR LATITUDES : MAJOR >>--------------------------------- >>--------------------------------- >> PROBABLE SI ASSOCIATION : 90 ESTIMATED GLOBAL IMPACT: MAJOR >> >> >>ESTIMATED FORECAST PEAK PLANETARY 24-HOUR A-INDEX DURING STORM: 55 TO 70 >> ---- --------------- >> >> >>COMMENTS: >> >> >> Activity is expected to begin primarily on 06 November with the >>arrival >>of one of the coronal mass ejections related to one of the stronger >>minor >>M-class flares observed. This activity could result in periods of minor >>to >>major geomagnetic storming on 06 November. The largest disturbance is >>expected to arrive with a fairly vigorous shock-front on 07 November and >>produce periods of major to severe geomagnetic storming. Currently, the >>activity on 07 November is expected to reach or exceed major storm >>levels. >>A return to quieter levels of activity is not expected until later on 08 >>November, barring further solar outbursts. >> >> >> A middle latitude auroral activity warning has been issued as well >>as a >>low latitude auroral activity watch for 06 and 07 November. Consult the >>web >>page at: http://solar.uleth.ca/solar/www/aurpred.html for supporting >>graphics >>forecasts. >> >>** End of Warning ** > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Al Allworth Subject: Solar Cycle Status Report Date: Thu, 6 Nov 1997 18:03:31 -0800 (PST) >X-Sender: caschue@...................... >Date: Thu, 06 Nov 1997 12:27:40 -0500 >To: Al - W7PXX , > Ed Bathgate RMA Repair Dept , > Bruce Erkkila-KC5OV , > Bruce Erkkila-KC5OV , > Don Hillger , > John K 5 J J , > "Jerry L. Rowe" , > Gary Shay , > Gary Barr-WA6TWT , > Richard Barth-W3HWN , > Dan Bathker , > Don Bennett-N7TF , > Shayla Taylor-KA5PRZ , > Felipe Arroyo , > Dick Foster , Bob Foster , > Muse Mann , > David Maples-WB4FUR , > Bill Notley-KD6ZXI , > Paul Robbins-KC6ZLW, > Steve Schindler-WD4MJJ, > "W. Russell Slye" , > Steve Veader , W6VPH , > H F WRIGHT , > Ron Grandmaison , > N V Pollack-KA3ENO , > Fred Fredlock-N4KVN , > Michael Cauley , > Marv Storey , > Steve Wnuk , > AA1BU , > AA2NN , K4VV , > K9ICF , > KC1SE , > KE7UA , N1OJ0 , > W1TCF , > W8XO , > WG3A , WN3X , > WX2S , > "Robert A. Kile-KG7D" , > EDMOND BRADY , > Zeke , > , , > Albert H Zimmerman-W8UYN , > "Paul J. Poling-N8CKG" >From: henry schuett >Subject: Solar Cycle Status Report >Cc: Roberto.J.Acosta@.............. Godfrey.Anzic@.............. > Terry.L.Bell@.............. Joseph.M.Berki@.............. > Bruce.L.Bream@.............. Michael.A.Cauley@.............. > Donald.E.Costello@.............. William.T.Dedula@.............. > Douglas.C.Dolch@.............. Alan.N.Downey@.............. > Patrick.W.Dunn@.............. Michael.W.Goin@.............. > Raiford.E.Hann@.............. Don.R.Hilderman@.............. > Thomas.J.Hill@.............. Louis.R.Ignaczak@.............. > Kenneth.A.Jensen@.............. Brad.W.Kaustinen@.............. > David R Kifer , > Ihor.Kramarchuk@.............. Steven.W.Mainger@.............. > Joseph.Maziarz@.............. James.H.McKim@.............. > Robert.C.Mate@.............. Steven.W.ODonnell@.............. > Richard.L.Patterson@.............. William.J.Rieke@.............. > Michael.A.Robertson@.............. Noel.B.Sargent@.............. > Richard.R.Scheske@.............. Philip.A.Stehno@.............. > Russell.E.Steinbach@.............. William.H.Stokes@.............. > Steven.J.Struharik@.............. Daniel.M.Vento@.............. > Lawrence.W.Wald@.............. > KC8F , > Stephen.P.Wnuk@.............. 71026.1561@............... > Glenn L Williams , > kc4iyd@....................... > Nancy Rabel Hall , > Greg Romaniak-N8XOS, > Earl-N7BYL > >Subject: Solar Cycle Status Report >>Date: Wed, 5 Nov 1997 15:06:17 -0500 >> >> >>Solar Cycle Status Report >> >>STATUS OF THE CURRENT SOLAR CYCLE: >> >> Everyone now agrees that we have finally observed the birth of >>solar >>cycle 23. We have probably been immersed within this new cycle for some >>time. According to sunspots, the minimum occurred in May 1996 with an >>as yet >>unofficial smoothed sunspot number of 8.1. Since then, we have observed >>a >>steady increase in the number of new-cycle sunspots having the proper >>new-cycle magnetic polarities. At the time of this writing, most of the >>new >>sunspots which are appearing are new-cycle spots. >> >> >> According to the number of days in which no sunspots appeared, the >>cycle >>minimum (or maximum number of spotless days) occurred in October 1996 >>when >>there were 26 spotless days. This month also corresponds with the >>lowest >>monthly observed sunspot number of 2.3 (reported by SEC) and 1.8 >>(according >>to the International Relative Sunspot Number [RI]). >> >> >> In addition, butterfly plots showing the emergence of new solar >>sunspot >>regions according to solar latitude indicates a clear separation in >>formation >>latitudes from old cycle 22 and new cycle 23. There are also many other >>parameters which have shown that new cycle 23 is now firmly in-progress. >> >> >> This conclusion is a mixed-blessing for industry. >> >> >> Radio communicators can now begin to look forward to an >>increasinglyproductive reign of ionospheric radio communications. In >>fact, higher-band >>high-frequency (HF) radio communications are already beginning to be >>observed. By July of 1998 (within the next 12 months), the observed >>sunspot >>number should almost triple in magnitude from a current predicted >>smoothed >>value of 40 for June 1997 (predicted through regression methods) to 109 >>(plus >>or minus 25) by July 1998. This will substantially increase the >>strength of >>the ionosphere. The next year will therefore be an exciting one for >>radio >>communicators. >> >> >> The predicted smoothed sunspot number over the next 9 years is >>predicted to follow this pattern: >> >> >> Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec >>1997 019 022 027 030 034 040 044 050 054 060 066 071 >>1998 077 082 088 093 099 103 109 113 119 123 128 131 >>1999 136 139 142 146 148 151 153 154 156 157 158 159 >>2000 160 160 160 160 159 158 157 156 155 154 152 150 >>2001 148 146 142 140 137 134 131 128 124 121 118 114 >>2002 111 107 103 100 097 093 089 086 082 079 076 072 >>2003 069 066 062 060 057 053 051 048 046 043 041 039 >>2004 036 034 032 030 028 027 024 023 021 020 019 017 >>2005 016 014 013 012 012 011 010 009 009 008 *** *** >> >> >> The predicted smoothed 10.7 cm solar radio flux values over the >>next 9 >>years is predicted to follow this pattern: >> >> >> Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec >>1997 077 080 084 087 091 096 100 105 109 114 119 124 >>1998 129 134 139 144 149 153 158 162 167 171 175 178 >>1999 182 185 188 191 193 196 198 199 201 202 203 204 >>2000 205 205 205 205 204 203 202 201 200 199 197 195 >>2001 193 191 188 186 183 181 178 175 172 169 166 163 >>2002 160 156 153 150 147 144 140 137 134 131 128 125 >>2003 122 119 116 114 111 108 106 103 101 099 097 095 >>2004 092 091 089 087 085 084 082 081 079 078 077 075 >>2005 074 073 072 071 071 070 069 068 068 067 *** *** >> >> >> Satellite operators and users of satellite technology are less >>impressed >>with the onset of this new cycle of activity. The increased number of >>sunspots implies an attendant increase in the number of solar flares >>capable >>of spewing out particles that can charge and damage sensitive electronic >>components. The number of associated Earth-directed coronal mass >>ejections >>will also increase. This all means that users and owners of satellite >>technology will have to be increasingly aware of potential Earth-bound >>interplanetary disturbances. The death of the Telstar 401 satellite has >>beenunofficially attributed to the arrival of such a disturbance, >>combined with >>the effects of higher-than-normal densities of energetically charged >>electrons. That particular interplanetary disturbance was about the >>size of >>a mouse when you think of what is yet to come over the next 4 to 6 >>years. >>The largest interplanetary disturbances which we will observe during >>solar >>cycle 23 may be closer in size to an elephant than the small mouse we >>observed that may have contributed to the sudden death of Telstar 401. >>The >>overwhelming message which should be sent to users of satellite >>technology >>during this new solar cycle is "be cautious." >> >> >> Electrical hydro operators have enjoyed several years of quiet >>conditions. Nothing similar in magnitude to the events of March 1989 >>have >>been observed, where almost the entire electrical grid of electricity >>supplied to the province of Quebec collapsed within less than 2 minutes >>due >>to powerful electrical currents that were induced into Hydro Quebecs >>electrical power lines during one of the strongest geomagnetic storms on >>record. Since most of the electrical power lines and companies >>interconnect >>their lines, this outage had impacts all across North America. The >>additional load drawn from other power companies to compensate for the >>loss >>observed during the Quebec blackout brought many other power companies >>close >>to similar failure conditions. If the situation was slightly worse, >>other >>blackouts across North America could have been observed - possibly >>making >>this a much larger continent-wide type of power blackout instead of a >>relatively localized province-wide Quebec blackout. >> >> >> Oak Ridge National Laboratory studied the effects that a >>geomagnetic >>storm might have on the U.S. economy if the storm was only slightly >>larger >>than the one observed in March 1989. Their estimate of the impact of >>such a >>disturbance to the Gross Domestic Product alone put total economic costs >>in >>the U.S. in the $3 to $6 BILLION dollar range! This assessment, along >>with >>reviews conducted by the North American Electric Reliability Council >>placed >>the 1989 and 1991 geomagnetic storm events in a category equivalent to >>hurricane Hugo and the San Fransisco earthquake in its relative impact >>to the >>reliability of the electric power grids in North America. That's a >>sobering >>thought for hydro operators and everyone reliant upon electricity! >> >> >> The ability to predict conditions condusive to such large storm >>events >>will receive a considerable boost later this year when NASA's ACE >>satellite >>(Advanced Composition Explorer) is due to be launched. This satellite >>will >>provide near-continuous sampling of the space environment upstream of >>the >>Earth. It will provide as much as about 60 minutes of lead-time to the >>arrival of disturbances at the Earth. This should be sufficient time to >>allow hydro operators to prepare and watch for the damaging conditions >>that can follow interplanetary disturbances. >> >> >> Predictions of geomagnetic activity show that the number of minor, >>major >>and severe geomagnetic storms will steadily increase. The year with the >>maximum number of minor storm days is expected in the year 2005 during >>the >>decline of solar cycle 23 when the occurrence frequency of geoeffective >>coronal holes will reach a maximum. Over 40 minor storm days are >>expected in >>the year 2005. During the solar maximum year of 2000, coronal mass >>ejection >>induced minor storms should number at about 30 during the year. This is >>more >>than double the number of minor storm days expected during 1997. Major >>geomagnetic storming is expected to peak in the years between 1999 and >>2002. >>Severe geomagnetic storming, which is very difficult to predict, should >>peak >>in frequency between the years 1999 and 2005 with the preferred year of >>peak >>severe storm frequency being 2002. >> >> >> People interested in observing aurora's will be happy to know that >>we >>are well on our way to seeing larger events. Over the next 3 to 6 >>years, we >>will see many very significant auroral displays that should cover much >>of the >>U.S. and all of Canada. Activity observed during the last 3 years has >>been >>very miniscule compared to the events we can expect to observe during >>this >>new cycle. The largest of these events should be sufficiently intense >>to >>produce visible auroral activity from as far south as Florida! Although >>this >>is horrendous news for satellite users, radio communicators, navigators, >>surveyors and others, it is exciting news for those who love to watch >>for >>these awesomely powerful atmospheric displays of activity. >> >> >> The frequency and magnitude of solar flares is also expected to >>increase >>considerably over the next 3 to 6 years. Over the last few years, most >>of >>the solar flares we have observed have been very small and >>insignificant. As >>we approach the new millenium, the influence and power output of solar >>flares >>could increase by several orders of magnitude. The largest solar flares >>of >>this new solar cycle will almost certainly be at least 10,000 times more >>powerful than the majority of smaller flares we have observed over the >>last >>couple of years. These rogue flares could begin to be observed as early >>as >>1998 with a peak expected in the years between 1999 and 2003. >> >> >> Broken down, the number of M-class flares observed during an entire >>year >>should follow a pattern similar to this: >> >> >>1997 1998 1999 2000 2001 2002 2003 >>2004 >> 15 40 220 530 370 540 >> >> >> The number of X-class flares observed during an entire year should >>behave similar to this: >> >> >>1997 1998 1999 2000 2001 2002 2003 >>2004 >> 1 5 15 40 30 50 >> >> >> >> Major proton flare events capable of increasing proton densities in >>the >>near-Earth space environment are expected to reach a maximum between the >>years 1999 and 2003 with a double-maximum predicted for the years 2000 >>and >>2002. The number of predicted solar proton events is expected to >>increase >>slightly in 1998 and then more than triple between 1998 and 1999. There >>could be a fairly copious number of solar proton events during cycle 23. >>Estimates range from about 8 to as high as about 16 per year during the >>years >>of maximum proton flaring. >> >> >> These are just a few of the events we can expect to observe during >>this >>new solar cycle. >> >> >> The new millenium should be ushered in a BANG! Periods of solar >>activity will be observed that will be capable of literally shaking >>space! >> >> >>Everything from current solar and geophysical indices to >> current auroral activity sighting reports, daily reports, alerts and >> warnings, and much more can now be found at: >>http://solar.uleth.ca/solar >> >> >> >> > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: latest addition Date: Fri, 07 Nov 1997 19:13:33 +1200 greetings all, on behalf of the group I extend a warm welcome to Francesco Nucera, he is from central Italy not too far from all that activity a few weeks ago. he is also the 3rd Itilian station on the map and in the database. BTW some very good looking seismograms from you guys from the Calif./Nev. events etc. chow Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: monster event Date: Sun, 09 Nov 1997 00:40:39 +1200 tibet region of China 97/11/08 10:02:48 35.04N 87.31E 10.0 7.9Ms A XIZANG Dace Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: francesco Subject: LARGE EVENT 7800 km from Italy Date: Sat, 08 Nov 1997 18:54:59 +0100 My station have registered a large event today at 10.12,25 GMT The preliminar location show an event about =7 Mb 7800 E from Italy, (India - China border region) Confermed by USGS **************************************************************************** ******************** FRANCESCO NUCERA Osimo - Ancona - ITALY Lat. 43.48N Long. 13.48E donjuan@........... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: faults in the northern Xizang? Date: Sat, 08 Nov 1997 11:01:22 -0700 My maps do not show the faults in the northern Xizang Province. I have the Altyo Tagh along the Kulan Shan but today's Mw 7.6 quake seems to be some distance to the south. The Harvard CMT focal mechanism suggests strike-slip movement along an east-west direction. They also suggest the quake was shallow >> surface ruptures are likely. Anyone have an idea what fault system today's quake may have been on? -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Francesco Subject: Re: faults in the northern Xizang? Date: Sat, 08 Nov 1997 21:56:38 +0100 Hello Charles, could you beep me a good mapit program, w95 compatible, for isolate the events easily, knowing latitude and longitude? (even to download on the web) Thank you very much Francesco Nucera Osimo - Ancona Italy At 11.01 08/11/97 -0700, you wrote: >My maps do not show the faults in the northern Xizang Province. I have >the Altyo Tagh along the Kulan Shan but today's Mw 7.6 quake seems to be >some distance to the south. The Harvard CMT focal mechanism suggests >strike-slip movement along an east-west direction. They also suggest the >quake was shallow >> surface ruptures are likely. > >Anyone have an idea what fault system today's quake may have been on? > > >-- >---/---- >Charles P. Watson, Consulting Geologist >Advanced Geologic Exploration >Seismo-Watch / Earthquake Information Services >Voice: 702-852-0992 / Fax: 702-852-3226 >Office Location: 39.43N 119.71W >mailto:watson@................ >http://www.seismo-watch.com > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: lahr@................. (Dr. John Lahr (USGS-GI Seismologist)) Subject: XIZANG Mw 7.4 - 7.6 earthquake Date: Sat, 8 Nov 1997 14:42:26 -0900 > From condor@................ Sat Nov 8 03:14:08 1997 > From: condor@................ > Date: Sat, 08 Nov 1997 05:16:52 MST > To: lahr@................. > Subject: From KOYANAGI via USGS EasyNet > > > Message processed by EasyNet 08 Nov 1997 at 12:16 UTC: > > From: NEIS::KOYANAGI "Stuart Koyanagi" 8-NOV-1997 05:15:41.00 > To: CONDOR > CC: > Subj: EQ MAG 7.9 XIZANG > > U.S. GEOLOGICAL SURVEY NATIONAL EARTHQUAKE INFORMATION CENTER > World Data Center A for Seismology > > Reply to: sedas@................ (internet) > sedas@................. (internet - alternate) > ISDMNL::NEIS::SEDAS (SPAN) > > The following is a release by the United States Geological Survey, > National Earthquake Information Center: A major earthquake occurred > IN XIZANG about 430 miles (700 km) north-northwest of Lhasa or about > 520 miles (840 km) north-northeast of Kathmandu, Nepal at 3:03 AM > MST today, Nov 8, 1997 (6:03 PM local time in Xizang). A > PRELIMINARY MAGNITUDE OF 7.9 WAS COMPUTED FOR THIS EARTHQUAKE. The > magnitude and location may change slightly as additional data are > received from other seismograph stations. No reports of damage or > casualties have been received at this time; however, this earthquake > may have caused damage due to its size. This earthquake is believed > to be the largest instrumentally recorded event in this area to > date. > > >Date: Sat, 8 Nov 1997 14:12:42 -0700 (MST) > >From: Stuart Sipkin > > 97/11/08 10:02:48.81 > XIZANG > Epicenter: 35.044 87.310 > mb 6.1 MS 7.9 > > MOMENT TENSOR SOLUTION > Depth 29 No. of sta: 20 > Moment Tensor; Scale 10**20 Nm > Mrr= 0.16 Mtt=-1.04 > Mff= 0.88 Mrt= 0.09 > Mrf= 0.02 Mtf= 1.19 > Principal axes: > T Val= 1.45 Plg= 3 Azm=296 > N 0.16 86 75 > P -1.61 2 206 > > Best Double Couple:Mo=1.5*10**20 > Mw=7.4 > NP1:Strike=341 Dip=86 Slip= 180 > NP2: 71 90 4 > > > ------- > ###-------------- > ######--------------- > #########---------------- > ###########----------------- > T ############----------------- > ############----------------- > ################-----------###### > #################-----########### > ################################# > ###########-------############### > ######------------############### > ------------------############# > -------------------############ > ------------------########### > -----------------######## > -- ----------###### > P -----------### > ------- > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: Alabama 10/24/97 Date: Wed, 12 Nov 1997 18:26:16 -0700 Charlie Rond and the PSN- That is a very nice record of the Atmore, Alabama, Earthquake. I have just returned to the office after leaving somewhat unexpectedly for Alabama on Monday 27 Oct to assist in a USGS aftershock investigation of the earthquake. I had intended to email the PSN-L from the field, but I encountered some connectivity problems and wasn't online from the motel until just before we left on Saturday 1 Nov. Following the field study, I spent a week at a Buddhist meditation retreat that I had scheduled prior to the earthquake: just an attempt to deal with my internal signal/noise problems. I plan to put some of the Alabama aftershock records we recorded with portable seismographs on a USGS website in the near-future. In the meantime, I am forwarding an email from Joan Gomberg, USGS/CERI at the University of Memphis, who coordinated field activities that summarizes the earthquake investigation. -Edward PS. It has taken me almost two days to go through the mostly PSN-L email of the past two weeks. Charlie Rond wrote: > > Larry, > > Here is a late delivery on the Alabama 4.9 event. I'm having to learn > how to upload these to your page. > > --Charlie Rond > > --------------------------------------------------------------- > > Name: 971024A.RM1 > Part 1.2 Type: unspecified type (application/octet-stream) > Encoding: base64 > > --------------------------------------------------------------- > > Charlie Rond -\/\--Public Seismic Network-Memphis > rond@................ (901) 360-0302 [ free BBS ] > http://gandlf.ceri.memphis.edu/~rond http://gandlf.ceri.memphis.edu/~rond/psn -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: [Fwd: seismographic quotation and info] Date: Wed, 12 Nov 1997 18:54:27 -0700 -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". Hi ! Please send aproximate price references of low end seismographic equipment. We are an astronomical observatory, where hi precission instrumentes (telescopes) are pointing to the sky with arc-second accuracy. The telescopes are normally "pointed" to an object based on theoretical or mapped coordinates, which are corrected for instrumental errors (telescope mechanical optical flexure) with apropiate ponting-software model, which has several degree parameter inputs. The pointing is in general quite satisfactory, however sometimes we detect some (small) "jumps" which are not readily explained. We believe it coud be seismic activity (?). In order to prove (or not) we need some seismographic instrumentation which gives enough data for our pourposes, which is probably much less demanding than the normal commercial or scientific applications. We are on a tight budget, so we are looking for some simple solution. We think that a common accelerometer with some hi sensitivity low-pass amplifier hooked to a PC may probably do, but have no experience.... Your comments and suggestions are most WELCOME !!! Thank you !! :-) Gero *--------1---------2---------3---------4---------5---------6----- * Gero Timmermann gtimmerm@....... home: (56-2) 273-4348 * http://www.eso.org/~gtimmerm CUSeeMe: 134.171.81.90 * European Southern Observatory, ESO LaSilla, Mangmt,Tech.Supp. * POBox 19001, Santiago-19, CHILE - Phone: (56-2) 207-3397 x4456 *********1*********2*********3*********4*********5*********6 From: Edward Cranswick Subject: [Fwd: ] Alabama Earthquake Date: Wed, 12 Nov 1997 18:58:17 -0700 -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". Friends of the 10/24/97 Alabama Earthquake... Here is an abbreviated report on our field experience and a rough list of things that I think need to get done to put together a complete story about this earthquake sequence (am sure it's by no means complete). I'm willing and interested in trying to coordinate all these activities (would also be happy to share this responsibility with someone), and certainly hoping that y'all (my 'southern' really improved last week) will be interested in participating by volunteering to do some piece of the study. Please let me know if I've forgotten something, or someone who might also be interested in participating in this, or if you're not interested. As you see, there are lots of interesting pieces, and opportunities for good collaborative work and publications. Last week's field activities included deployment of a now 11 station seismic network (Tom Bice, David Carver, Edward Cranswick, Lorraine Wolf, and myself), collection of intensity information (Dorothy Raymond), preliminary examination of available data from the Alabama State Oil and Gas Board (Dorothy Raymond, Richard Raymond, Lorraine Wolf, and myself). Assistance was also provided by the Escambia County Emergency Management Agency, and lots of local citizenry. There were two felt aftershocks and at least three smaller ones evident in preliminary examination of the seismic data recorded. Seismographs were operated in continuous recording mode for two to five days and are all still in the field running in triggered mode. Two MEQs were also operated for ~five days. The intensity information seems to be quite consistent with preliminary instrumental locations. There may be one example of ground failure (?), although it is quite subtle, if real. The State Oil and Gas Board is willing to provide any of their records, which include monthly logs of well head pressures, volumes of fluids injected or withdrawn, etc. The epicentral region is quite close (within a few km) to one of the smaller fields and within ~10 km from the largest fields. Both passive production and injection (forgive use of inappropriate terms!) are done, and well depths range from 5000' to 15000'. The primary fault system runs within a few km of the epicentral region. The following is my 'to do' list organized loosely by topic. Seismology Examine closest permanent station data (CERI's Pickwick station, Tim Long's?) for evidence of prior activity in the same area. Determine focal mechanisms from regional data (Bob Hermann and Chuck Ammon have already begun this). Prepare portable seismographic data for analysis Compile all field notes Organize data recorded to date in PASSCAL database Compile site information (for ground motion studies) Identify all events, produce catalog (locations, magnitudes, focal mechanisms?) Prepare SEED volume for IRIS DMC Service/recover field instrumentation Cluster test to verify responses, polarities? Oil and Gas Data Compilation & Analysis Contact expert from USGS Energy Team? Determine relevant information to compile. Computerize (logged information is available in printed format). Correlate with seismologic and geologic information. Intensity Compile data for all felt events from newspaper and post-office solicitations. Determine mainshock isoseismal limits - to constrain depth and attenuation, possible directivity? Compare mainshock and aftershock intensity patterns, intensity and instrumental info. Find out if oil or gas pipelines were damaged. Misc. Search newspapers for previous reports of earthquakes in the region. Determine if there's any geodetic information from the region. GIS? Mapping Prepare a base map with geology, geography (Susan Rhea has already started a GIS map?). Add seismic station locations, instrumentally determined information. Prepare layer with intensity information. Prepare layer with production field information. Joan Gomberg US Geological Survey c/o The University of Memphis Campus Box 526590 Memphis, TN 38152-6590 (901) 678-4858 (901) 678-4897 (FAX) From: Edward Cranswick Subject: Re: seismographic quotation and info Date: Wed, 12 Nov 1997 19:15:40 -0700 Gero- You could buy a commercial seismograph for $10k-$20k or use a PC in conjunction with a some other hardware/software costing about $1k. I have forwarded your email to the Public Seismic Network listserver and you should receive some suggestions from them. Since you observe "jumps" which would seem to be displacements of the pointing direction, perhaps it would be more useful to record velocities rather than accelerations. For the first step, I suppose the most important matter is to determine whether there is any temporal correlation between the "jumps" and independently recorded seismic events. Do you have a way of precisely recording the time of the "jumps". -Edward Gero Timmermann wrote: > > Hi ! > > Please send aproximate price references of low end seismographic > equipment. > > We are an astronomical observatory, where hi precission > instrumentes (telescopes) are pointing to the sky with > arc-second accuracy. > The telescopes are normally "pointed" to an object based on > theoretical or mapped coordinates, which are corrected for > instrumental errors > (telescope mechanical optical flexure) with apropiate > ponting-software model, > which has several degree parameter inputs. > The pointing is in general quite satisfactory, however sometimes > we detect some (small) "jumps" which are not readily explained. > We believe it coud be seismic activity (?). > In order to prove (or not) we need some seismographic > instrumentation which gives enough data for our pourposes, which > is probably much less > demanding than the normal commercial or scientific > applications. We are on a > tight budget, so we are looking for some simple solution. > > We think that a common accelerometer with some hi sensitivity > low-pass amplifier hooked to a PC may probably do, but have no > experience.... > > Your comments and suggestions are most WELCOME !!! > > Thank you !! :-) > Gero > > *--------1---------2---------3---------4---------5---------6----- > > * Gero Timmermann gtimmerm@....... home: (56-2) 273-4348 > > * http://www.eso.org/~gtimmerm CUSeeMe: 134.171.81.90 > * European Southern Observatory, ESO LaSilla, Mangmt,Tech.Supp. > > * POBox 19001, Santiago-19, CHILE - Phone: (56-2) 207-3397 x4456 > > *********1*********2*********3*********4*********5*********6 -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Iceequeen@....... (by way of Larry Cochrane ) Subject: Telemetry Date: Wed, 12 Nov 1997 22:08:06 -0700 Hi Everyone, I received this from Katie the other day. If you have any info for her please send it directly to her since she is not on the list. KATIE UNDERWOOD 17 HIGHLAND MEADOWS DRIVE JACKSON, MISSISSIPPI 39211 (601) 362-1355 ICEEQUEEN@....... Dear Mr. Cochrane: I am a junior at Saint Andrew's Episcopal School in Ridgeland, Mississippi. For the past two years, I have been conducting extensive independent research in the field of engineering, specifically designing seismographs. Consequently, I have become involved in science fairs and science competitons. Last year I built a modified version of the James D. Lehman seismograph, with plans downloaded from the PSN website, as well as one of your amplifer boards. The modified Lehman proved very successful, graphing earthquakes around the country, including the Clakre County, MS earthquake March 25, 1996--the only seismograph in the state to record it. Do to a successful year in state science fair competitions, I was selected to represent Mississippi in the 47th International Science and Engineering Fair held in Tucson, AZ. This year I designed a portable seismograph using three accelerometer sensors, which are positioned to measure x, y, and z axes. The seismograph is unique in that it does not have to be balanced and is rugged enough to be thrown or possibly launched from almost any location and still accurately record both motions and vibrations. I have hypothesized that this device will not be sensitive enough to record long-distance earthquakes, and my current observations confirm this. However, I do believe that it can be used for many applications beyond seismic research. Due to its ability to measure and record the intensity and direction of vibrations and other disturbances, I have hypothesized that its outputs could be fed to a modified flight recorder "black box." I believe that this information could be used to analyze and determine the cause of many in-flight anomalies, such as strength, direction, and perhaps the location of unusual vibrations, accelerations, or other movements. If the hypothesis proves correct, this analytical ability could prove valuable in determining the cause of various mechanical and structural failures, and might assist in predicting and avoiding some of these same problems. This spring I was selected to represent Mississippi again in the 48th Intel International Science and Engineering Fair held in Louisville, Kentucky. At the fair, I received a first place award from the Society of Exploration Geophysicists, a second place award from the United States Department of the Interior, Bureau of Reclamation, as well as Third Place Grand Award in the Engineering Category from Intel. I am interested in conducting experiments with my portable seismograph using accelerometer chips. It would be most convenient if I had an A-D converter that would plug into my notebook computer PCMCIA slot. I have noticed that Jameco has a PCIA-7IB card avaliable. Do you have any experience with this model, or could you make any recommendations for a PCMCIA card compatible with the SDR software? I am also interested in the Telemetry Demodulator Board advertised of the PSN website, but I was unable to upload any further descriptions or cost information of the device. I would like to construct a telemetry link between my portable sensor and a receiver to be located at my notebook computer. Any information of ideas you have would be gratefully appreciated. Sincerely, Katie Underwood _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: David Josephson Subject: Re: Telemetry Date: Thu, 13 Nov 1997 00:39:10 -0800 (PST) Hello Katie, Good to see that there is *someone* young doing independent science and technology research! My thing was radio (broadcasting, propagation, and audio) and after playing with corporate America for 12 years I started my own company making new and different kinds of microphones. Unless it's changed a lot, school will not be aligned with your sort of independent work, but if you play it right you can take what you can use and keep your own ideas intact. Using a three-axis array of solid state or piezoelectric accelerometers is a good way to record any sort of vibration or shock signature. But as you know more sensitivity is needed for earth seismic use. Your idea about using it in aircraft is good -- but old! During flight test, aircraft are heavily instrumented with accelerometers to monitor vibration of critical surfaces, and many modern jets include vibration sensors in the engines to detect shaft and bearing wear. These feed the "black box" either directly or through a flight management computer. The idea of a thrown sensor is also known -- during the Vietnam war, sensors were developed with single and three-axis geophone type sensors that triggered small radio transmitters whose signals were picked up by aircraft. They were commonly used to detect movement on trails. I'll leave the PCMCIA card issue to others more familiar with it but I can address your question on telemetry. In principle this is quite simple: a radio carrier is modulated with a tone, the frequency of which is varied to correspond with the voltage coming from the sensor. You can combine several tones on one radio carrier, each one representing one sensor (or one axis of a multi-sensor system). The USGS uses this extensively as I'm sure others will explain. Larry's board is set up to receive the signals in the USGS standard format, which you could easily duplicate using amateur radio frequencies. The decoder (Larry's board or another) receives the tone and translates it back into the original signal. FOr instance if you say it's a 2 kHz carrier with 500 Hz deviation, that means that the one would be at 2 kHz with no signal, 1500 Hz with a signal at its maximum negative swing, 2500 Hz at maximum positive, and linearly interpolated values in between. Good luck with your work! -- David Josephson / Josephson Engineering / San Jose CA / david@............. ///for more information see http://www.josephson.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Charlie Rond Subject: Re: Alabama 10/24/97 Date: Thu, 13 Nov 1997 04:28:23 -0600 Edward, > That is a very nice record of the Atmore, Alabama, Earthquake. I have >just returned to the office after leaving somewhat unexpectedly for >Alabama on Monday 27 Oct to assist in a USGS aftershock investigation of >the earthquake. I had intended to email the PSN-L from the field, but I >encountered some connectivity problems and wasn't online from the motel >until just before we left on Saturday 1 Nov. Following the field study, >I spent a week at a Buddhist meditation retreat that I had scheduled >prior to the earthquake: just an attempt to deal with my internal >signal/noise problems. > I plan to put some of the Alabama aftershock records we recorded with >portable seismographs on a USGS website in the near-future. In the >meantime, I am forwarding an email from Joan Gomberg, USGS/CERI at the >University of Memphis, who coordinated field activities that summarizes >the earthquake investigation. >-Edward > >PS. It has taken me almost two days to go through the mostly PSN-L >email of the past two weeks. Thanks for your message and kudos. I'd be very interested in seeing the aftershock records and hearing your comments about your investigation. Do you think this was related to past drilling in the area? Also could use some of those quieting vibes from your retreat. Charlie Rond -\/\--Public Seismic Network-Memphis rond@................ (901) 360-0302 [ free BBS ] http://gandlf.ceri.memphis.edu/~rond http://gandlf.ceri.memphis.edu/~rond/psn _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Seismology text books Date: Thu, 13 Nov 1997 10:38:39 -0500 Hi gang, A question for academics, students and/or recent graduates in seismology--What are the current seismology textbooks, either beginning o= r advanced? A nice map of the last 2 weeks of M>2 earthquakes in the continental US= can be found at www.geophys.washington.edu/CNSS/us.epi.gif Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Steve Hammond Subject: Mammoth Lakes Date: Fri, 14 Nov 1997 20:45:10 -0800 Mammoth has had several 4.0 or greater and over 150 smaller events in the last 24 hours. Does anybody know the URL of a web site dedicated to info on this volcano? http://quake.usgs.gov/recenteqs/Maps/119-38.html offers a site map however I would also like to read some comments. Regards, Steve Hammond PSN San Jose _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Steve Hammond Subject: Re: Mammoth Lakes Date: Fri, 14 Nov 1997 21:00:46 -0800 http://quake.wr.usgs.gov/VOLCANOES/LongValley/ Ask and you receive... got this off-line from a fellow I work with. Regards-- Steve Hammond wrote: > Mammoth has had several 4.0 or greater and over 150 smaller events in > the last 24 hours. > Does anybody know the URL of a web site dedicated to info on this > volcano? > http://quake.usgs.gov/recenteqs/Maps/119-38.html offers a site map > however I would also like > to read some comments. > > Regards, Steve Hammond PSN San Jose _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Mammoth Lakes Date: Thu, 13 Nov 1997 15:08:32 -0700 Steve, Here are the M3+ quakes at Mammoth Lakes in the past 24 hours: Mag local time MAP 3.0 97/11/13 12:41:38 37.64N 118.90W 5.1 4 mi E of MAMMOTH LAKES MAP 3.9 97/11/13 11:42:22 37.65N 118.90W 5.8 4 mi E of MAMMOTH LAKES MAP 3.0 97/11/13 05:26:58 37.65N 118.90W 5.6 4 mi E of MAMMOTH LAKES MAP 3.1 97/11/13 04:50:29 37.65N 118.90W 5.5 4 mi E of MAMMOTH LAKES MAP 3.1 97/11/13 04:35:07 37.63N 118.90W 5.2 4 mi ESE of MAMMOTH LAKES MAP 3.0 97/11/13 04:34:49 37.65N 118.90W 4.9 4 mi E of MAMMOTH LAKES Source: http://quake.wr.usgs.gov/recenteqs/Quakes/quakes.big.html http://quake.wr.usgs.gov/recenteqs/Maps/Long_Valley.html http://quake.wr.usgs.gov/QUAKES/CURRENT/norcal.list But there have been a TON of M1's and M2's! Golly, at a quick glance it looks like it really took off at 2000 UTC - just after the largest event, a M3.9. Here is a quick total of events/hour: Nov 13 Time events/hr 1000 3 1100 2 1200 17 1300 34 1400 18 1500 7 1600 10 1700 14 1800 10 1900 24 2000 55 2100 54 2100 34+ Eeeeeek! And to think Dave Hill is at Mammoth Lakes this week. I bet he is going nuts! -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Francesco Subject: MAJOR QUAKE IN EASTERN MEDITERRANEAN SEA Date: Fri, 14 Nov 1997 23:53:14 +0100 Hi all, at 21.41 my station have registered a major event, preliminary localizated in eastern mediterranean sea, Turkey/Greece border region. MG >= 6 mb The same quake was registered by other private italian station. We are waiting for more information from Neis or CdidcOrg. FRANCESCO NUCERA OSIMO - Ancona - ITALY Lat. 43 29" E - Long. 13 29" E _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Spring Material Date: Fri, 14 Nov 1997 15:00:45 -0800 Hi All -- I'm still working on a vertical force-balance seismometer design and hope to balance the acceleration of gravity with the use of a coil extension spring supporting the mass. However, the requirements of this spring are pretty severe, or so it seems: 1) Non-magnetic and 2) Good stability over time periods to a couple of minutes. The stability requirement appear to dictate either that for a given spring geometry the temperature coefficient of expansion of the material cancel the temperature coefficient of the modulus of elasticity, or that both be close to zero. There is a material -- Ni-Span C -- that has the needed temperature characteristics, but it's magnetic. And I wouldn't know where to look for some wire to make a spring out of. I think non-magnetic stainless spring wire might work along with very good thermal insulation, but I haven't found a source for small quantities of this either. Does anyone out there have any ideas or suggestions? Thanks, Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: MAJOR QUAKE IN EASTERN MEDITERRANEAN SEA Date: Sat, 15 Nov 1997 11:10:05 +1200 yep it is just arriving at the Kippa, Hawaii station. Dave At 11:53 PM 11/14/97 +0100, you wrote: >Hi all, >at 21.41 my station have registered a major event, preliminary localizated >in eastern mediterranean sea, Turkey/Greece border region. >MG >= 6 mb > >The same quake was registered by other private italian station. > >We are waiting for more information from Neis or CdidcOrg. > > >FRANCESCO NUCERA >OSIMO - Ancona - >ITALY > >Lat. 43 29" E - Long. 13 29" E > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Robert L. Thomasson" <102073.3346@..............> Subject: Spring Material Date: Fri, 14 Nov 1997 18:51:58 -0500 Karl, When I was in school at Cal Poly SLO, there was a company in Santa Maria,= CA called California Fine Wire Co, that specialized in all kinds of exot= ic wire and made donations to us students for our projects. If they're stil= l there they might be able to help or point you in the right direction. = Sorry I don't have a phone or address for them, as it's been awhile. You might also try a McMaster-Carr catalog. They have an amazing inventory. Good Luck, Bob Thomasson _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: Spring Material Date: Fri, 14 Nov 1997 18:09:10 -0600 Karl Cunningham wrote: > > Hi All -- > > I'm still working on a vertical force-balance seismometer design and hope > to balance the acceleration of gravity with the use of a coil extension > spring supporting the mass. > > However, the requirements of this spring are pretty severe, or so it seems: > 1) Non-magnetic and 2) Good stability over time periods to a couple of > minutes. > > The stability requirement appear to dictate either that for a given spring > geometry the temperature coefficient of expansion of the material cancel > the temperature coefficient of the modulus of elasticity, or that both be > close to zero. > > There is a material -- Ni-Span C -- that has the needed temperature > characteristics, but it's magnetic. And I wouldn't know where to look for > some wire to make a spring out of. > > I think non-magnetic stainless spring wire might work along with very good > thermal insulation, but I haven't found a source for small quantities of > this either. > > Does anyone out there have any ideas or suggestions? > > Thanks, > > Karl Cunningham > La Mesa, CA. > PSN station #40 > karlc@....... > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L A supplier in Florida, Small Parts Inc. has an assortment of SS spring wire sizes. I don't have the address handy but I can get it on Monday if necessary. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: Spring Material Date: Fri, 14 Nov 1997 17:12:05 -0800 Karl Cunningham wrote: ..... > I think non-magnetic stainless spring wire might work along with very good > thermal insulation,... > Does anyone out there have any ideas or suggestions? Karl: Thought I'd toss in my two cents worth! One idea that occurs is make the spring an integral part of a heater circuit. I.e., put power into the spring and heat it up to a temperature above any anticipated surrounding environment., but you use a circuit that uses the resistance of the spring as a temperature sensor at the same time. The result will be that it will hold the temperature of the spring itself within a fraction of a degree. The circuit looks something like this: +------+------------------| | | | \ \ | /R1 / SPRING | \ \ | | | | | | |\ | +------------------|- \ | | | | >-| | +-----------|+ / + | |/ | | \ \ / R2 /R3 \ \ | | +------+-----GND R1/R2 = Rspring/R3 at temperature, so you want a good low offset opamp such as an OP27 or one of the new chopper stabilized opamps such as TI makes, driving a power FET so that R3 can be small (for low power dissipation). The circuit uses it gain to drive power into the spring untill _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: Spring Material Date: Fri, 14 Nov 1997 17:16:29 -0800 Karl Cunningham wrote: ..... > I think non-magnetic stainless spring wire might work along with very good > thermal insulation,... > Does anyone out there have any ideas or suggestions? Karl: Thought I'd toss in my two cents worth! One idea that occurs is make the spring an integral part of a heater circuit. I.e., put power into the spring and heat it up to a temperature above any anticipated surrounding environment., but you use a circuit that uses the resistance of the spring as a temperature sensor at the same time. The result will be that it will hold the temperature of the spring itself within a fraction of a degree. The circuit looks something like this: +------+------------------| | | | \ \ | /R1 / SPRING | \ \ | | | | | | |\ | +------------------|- \ | | | | >-| | +-----------|+ / + | |/ | | \ \ / R2 /R3 \ \ | | +------+-----GND R1/R2 = Rspring/R3 at temperature, so you want a good low offset opamp such as an OP27 or one of the new chopper stabilized opamps such as TI makes, driving a power FET so that R3 can be small (for low power dissipation). The circuit uses the opamp gain to drive power into the spring until its resistance gets high enough to bring the bridge into balance where it will stay. Charles R. Patton ,Editor, Geo-Monitor http://www.iinet.com/users/patton patton@......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: Spring Material Date: Fri, 14 Nov 1997 07:55:44 -0800 Hi Karl I went to ACE hardware :-). Really. I bought 3 to 4 6" long springs with the smallest gauge and about 1/2" diameter (making an 18" long spring). The vertical sensor I made a while back was about 30" long and the spring attached to the support post about 4" above the knife edge pivot. I was able to get an approx. 20 sec period. I used a coil and magnet like the garden gate Lehman. I didn't run it for long so I'm not sure about temperature stability, but if you are measuring velocity and the coil/magnet is long maybe gradual vertical movements won't affect the sensors sensitivity. Barry PS. McMaster Carr also sells springs Karl Cunningham wrote: > > Hi All -- > > I'm still working on a vertical force-balance seismometer design and hope > to balance the acceleration of gravity with the use of a coil extension > spring supporting the mass. > > However, the requirements of this spring are pretty severe, or so it seems: > 1) Non-magnetic and 2) Good stability over time periods to a couple of > minutes. > > The stability requirement appear to dictate either that for a given spring > geometry the temperature coefficient of expansion of the material cancel > the temperature coefficient of the modulus of elasticity, or that both be > close to zero. > > There is a material -- Ni-Span C -- that has the needed temperature > characteristics, but it's magnetic. And I wouldn't know where to look for > some wire to make a spring out of. > > I think non-magnetic stainless spring wire might work along with very good > thermal insulation, but I haven't found a source for small quantities of > this either. > > Does anyone out there have any ideas or suggestions? > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Al Allworth Subject: Re: Spring Material Date: Fri, 14 Nov 1997 21:30:39 -0800 (PST) At 03:00 PM 11/14/97 -0800, you wrote: Hi Karl and all, Be careful with stainless steel wire. I have found some that is non-magnetic until it is bent beyond the elastic limit, then it becomes magnetic. I was very surprised when this happened to a part I was working on. Only the part that had been bent was magnetic. The change started where the bend was and it was quite abrupt. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Robert L. Thomasson" <102073.3346@..............> Subject: Re: Spring Material Date: Sat, 15 Nov 1997 01:45:50 -0500 <> This is very interesting. If I remember, 300 series (austenetic?) stainless steels are non-magnetic and 400 series are magnetic. I didn't realize the magnetic properties could change by bending. Anyone have an explanation? Bob Thomasson _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roger Baker Subject: Re: Spring Material, etc. Date: Sat, 15 Nov 1997 02:40:08 -0600 Friends, Incidently, my magnetic suspension force feedback seismometer, aka the jellybean, is small and highly temperature controlled and can fairly easily see earth tides except that magnetic micropulsations interfere with short term seismic data collection. Even two nesting sections of heavy iron pipe weighing a total of thirty pounds do not appear to shield it enough to kill the constant magnetic noise. Damn!--a near miss instrumentally speaking. It is not a bad gravimeter, is easy to build and very sensitive, but to make further progress I need to figure out some way to make it into either a pure seismometer or a pure magnetometer rather than a puzzling combination. I believe the following information is accurate. Correct me if I'm wrong. As I recall, one can use a pair of ordinary steel leaf springs to detect earth tides and seismic disturbances, in accord with R.V. Jones's paper on capacitance micrometers, if one encloses the device in a temperature controlled surrounding. In other words, small simple springs, perhaps even hacksaw blades, in a temperature controlled surrounding are good enough if you have some means to sense extremely small motions of your mass, on the order of parts per million. But such a spring and mass device, although very sensitive, will oscillate badly without damping and will not be very linear except for very small excursions. The LaCoste zero length spring suspension is clever and is a classic solution to building vertical motion seismometers. It uses a screen door looking coil spring on a slant to support a horizontal pivoted arm and effectively magnifies and lengthens the period of small displacements compared to a vertical spring and mass (for those who care, I heard that the secret of making genuine LaCoste zero length springs is to somehow pull them inside out). But all this is not needed if you use force feedback so that neither the linearity of the suspension nor oscillation nor natural period is a problem--since in this case you use a compensating force in a feedback loop to prevent any detectable motion at all. Thus you can use a simple vertical spring and mass to get good results -- assuming you use force feedback and extremely sensitive DC displacement detection methods. I suspect that the reason that the fellow who asked about springs wants his spring to be non-magnetic is that he wants to use a nearby magnet and coil combination for a motion detection sensor, but do be aware that LEDs and phototransistors in combination are very good down to nanometer displacements and give a DC signal, and that capacitance micrometers are the best of all. I wrote an article on how to build capacitance micrometers with mostly Radio Shack parts in my Science Hacker column in the latest Society for Amateur Scientists Journal. Magnetometer-wise, I have had some fun with a torsion device I made according to the suggestions I posted a few months ago. I ended up using a nylon fiber (less trouble in practice than a glass fiber although glass or quartz is the best way to go) and a Helmholtz coil to generate force balancing to recenter the suspended Radio Shack neodymium/iron/boron magnet (with a short section of copper tube to get near critical damping) and a laser pointer and phototransistor to detect rotation of a front surface mirror (you can dissolve the protective varnish off the silver on a cheap dime store mirror to make a front surface mirror with MEK solvent, and cut it with a glass cutter to make a nice little mirror chip a few millimeters across) attached to the magnet. The sensitivity of a torsion magnetometer is proportional to the strength of the magnet so the little rare earth magnets are splendid for this purpose. I also built an astatic magnetometer to test rocks and for general fun and experimentation. These are made with two magnets suspended in opposite directions so that the earth field force approximately cancels out and makes them sensitive primarily to local fields created by objects brought near to one or the other of the two well-separated magnets suspended by the torsion fiber. Although the earth field is canceled in theory this way, it never really is in practice and the device still sees micropulsations. In general, you want to have one or more fine ceramic tuning magnets a foot or more away to very nearly balance the earth's field, since it will ordinarily overwhelm the response of a torsion fiber magnetometer -- and give you just a plain old compass instead of a sensitive magnetometer. But you really want to see on the order of 1/50,000 of the earth field or one gamma. The best sensitivity is to be had when the earth's field is so exactly balanced by careful adjustment of the fine tuning magnets so that the dangling magnet/mirror combination is just on the edge of instability. Then the slightest change in the surrounding field will cause a detectable rotation of the mirror--such as even a slight change in the position of a small ceramic magnet perhaps ten feet away. Such devices are easy to build and can be incredibly sensitive and easily detect a car driving by maybe 50 feet away -- but they are normally in constant motion because of the constant background of magnetic micropulsations. Micropulsations were first discovered in the early seventeen hundreds by a fellow who discovered that his compass needle was trembling on its pivot when viewed through a microscope. Some days are magnetically much quieter than others, although there is generally a predictable daily (diurnal) variation. A well-known British instrumentationist named P.M.S. Blackett studied and optimised the physics of torsion fiber magnetometers and built the most sensitive astatic magnetometers then known by at least an order of magntitude. He used them in an isolated lab shed built with copper nails. The device itself was rather similar to mine. He speculated on but did not use force feedback. He published results in a long article in the proceedings of the British Royal Society, Vol. 245, Series A, Dec. 1952, pages 309-370. His elegantly simple magnetometer was only exceeded in sensitivity by the invention of the SQUID in the mid-sixties -- and I think it it would have been considerably better if he had used rare earth magnets. --Yours, Roger Baker _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: Spring Material Date: Sat, 15 Nov 1997 13:28:23 +0000 Karl Cunningham wrote: > There is a material -- Ni-Span C -- that has the needed temperature > characteristics, but it's magnetic. And I wouldn't know where to look for > some wire to make a spring out of. > > I think non-magnetic stainless spring wire might work along with very good > thermal insulation, but I haven't found a source for small quantities of > this either. > > Does anyone out there have any ideas or suggestions? Hi Karl, Over here in UK we have 'yellow pages'....lists of companies specialising in everything. We also have a web site for this, and I found MANY UK spring suppliers on it when I built my vert. seismo. I'm sure that you have the equivalent in your neck of the woods in USA. (The UK web site is www.yell.co.uk ). Regards, Albert Noble (England). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Arie Verveer Subject: Re: Spring Material Date: Sat, 15 Nov 1997 22:13:24 +0800 Karl Cunningham wrote: There is a material -- Ni-Span C -- that has the needed temperature characteristics, but it's magnetic. And I wouldn't know where to look for Some wire to make a spring out of. Try contacting : Peninsula Sprig Corporation http://www.peninsulaspring.com 6750 Silacci Way . Gilroy, Ca 95020 (408) 848-3361 Fax (408) 848-4118 I do recommend that you contact them via the FAX as I've never had much success via EMAIL. One idea that may be a possibility, is to use a thin Mica plate or even a microscope class cover slip as a spring and maybe some gold leaf as the connecting wires. Just an Idea. Regards Arie Verveer _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Brian Chesire Subject: Re: Spring Material Date: Sat, 15 Nov 1997 11:03:50 -0700 Hi All; One of the best low tempco spring materials I know of is trademarked "Elgiloy", it's a cobalt chromium-nickel alloy. Non-magnetic and stable from -300F to +850F. I don't know if they will supply small quantities or cost. All I have is the specs,the name and address. Elgiloy Limited Partnership, 1565 Fleetwood Dr., Elgin IL, 60123. Ph. 708-695-1900. I believe the originally were part of the Elgin watch company and developed the material for chronometers. As noted in some of the other posts, mechanical forming and working can have a lot of effect on the materials final behaviour. According to what I have, "Elgiloy" only reaches it full potential after being cold worked, rolled, drawn etc. so it should be safe to form any way you want. Brian Tucson, AZ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Francesco Subject: MONSTER QUAKE ???? Date: Sat, 15 Nov 1997 21:14:10 +0100 AT 19.19 ALL ITALIAN STATION HAVE REGISTERED A LONG PERIOD (9') OF WAVES THAT PROBABILY ARE A P WAVES. Not yet s or l waves Preliminary location of Neis: VANUATU ISLANDS Mg > 7.5 ! Who have registered the same schok? Best regards Francesco Nucera FRANCESCO NUCERA OSIMO - Ancona - ITALY Lat. 43 29" E - Long. 13 29" E _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: MONSTER QUAKE ???? Date: Sat, 15 Nov 1997 12:20:21 -0700 I just got this from the Alaska Tsunami Warning Center: ========================================================= TSUNAMI BULLETIN NUMBER 1 WEST COAST AND ALASKA TSUNAMI WARNING CENTER/NOAA/NWS ISSUED NOV 15 AT 1948 UTC ....THIS IS A TSUNAMI INFORMATION BULLETIN FOR ALASKA, BRITISH COLUMBIA, WASHINGTON, OREGON, AND CALIFORNIA ONLY... NO, REPEAT NO, WATCH OR WARNING IS IN EFFECT. AN EARTHQUAKE, PRELIMINARY MAGNITUDE 6.8, OCCURRED AT 0959 AST ON NOV 15, OR 1059 PST ON NOV 15, OR 1859 UTC ON NOV 15. THE EARTHQUAKE WAS LOCATED IN THE GENERAL AREA OF: VANUATU IS. NEAR 14.6S, 168.0E. THE PACIFIC TSUNAMI WARNING CENTER WILL ISSUE A TSUNAMI INFORMATION BULLETIN FOR HAWAII AND OTHER AREAS OF THE PACIFIC. EVALUATION: BASED ON LOCATION AND MAGNITUDE THE EARTHQUAKE WAS NOT SUFFICIENT TO GENERATE A TSUNAMI DAMAGING TO CALIFORNIA, OREGON, WASHINGTON, BRITISH COLUMBIA OR ALASKA. SOME AREAS MAY EXPERIENCE SMALL SEA LEVEL FLUCTUATIONS. THIS WILL BE THE ONLY BULLETIN ISSUED FOR THIS EVENT BY THE WEST COAST AND ALASKA TSUNAMI WARNING CENTER UNLESS CONDITIONS WARRANT.IF AVAILABLE, REFER TO THE INTERNET SITE (USE LOWER CASE) HTTP://WWW.ALASKA.NET/(TILDA)ATWC FOR MORE INFORMATION. ===================================================================== -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: MONSTER QUAKE ???? Date: Sun, 16 Nov 1997 08:24:13 +1200 I did in New Zealand and Tony in Hawaii also ...... Dave At 09:14 PM 11/15/97 +0100, you wrote: >AT 19.19 ALL ITALIAN STATION HAVE REGISTERED A LONG PERIOD (9') OF WAVES >THAT PROBABILY ARE A P WAVES. >Not yet s or l waves > >Preliminary location of Neis: VANUATU ISLANDS Mg > 7.5 ! > >Who have registered the same schok? > >Best regards Francesco Nucera >FRANCESCO NUCERA >OSIMO - Ancona - >ITALY > >Lat. 43 29" E - Long. 13 29" E > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: test Date: Sun, 16 Nov 1997 13:33:52 +1200 Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Huge Meteor Date: Sat, 15 Nov 1997 22:13:10 -0700 Geeze! I just finished putting down the kids and went outside to pick up the garbage can at the curb when a very large reddish-orange streak in the southern sky caught my eye. It was gone in a flash, but as it descended at about a 45° angle, the streak grew to incandescence white, expanding in width, then the leading front burst into a bright light and faded into a darkening orange, then black and was gone. It almost seemed like the Carson Range was lighted slightly by the event, then went back to its normal moon-lit mountain range at the night. Time: about 9:45 p.m. PST November 15 I had never seen anything like that before! It was huge, whatever it was. -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Huge meteor...space junk Date: Sat, 15 Nov 1997 22:22:07 -0700 Well, good ol' CNN had a story up on their web site in less than 20 minutes: http://www.cnn.com/TECH/9711/15/light.show.ap/index.html -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Huge Meteor Date: Sun, 16 Nov 1997 18:30:22 +1200 WOW !! did it caste a shadow at your location ?..... did you hear a boom= ?? I haven't seen a decent one for quite a while the last decent one seen in NZ was ~10 months ago and lit up the nthrn half of the South Is. of NZ, well to the nth of me.... for the hundreds that saw and heard the sonic booms said it made night like day =20 Dave At 10:13 PM 11/15/97 -0700, you wrote: >Geeze! I just finished putting down the kids and went outside to pick up >the garbage can at the curb when a very large reddish-orange streak in >the southern sky caught my eye. It was gone in a flash, but as it >descended at about a 45=B0 angle, the streak grew to incandescence white, >expanding in width, then the leading front burst into a bright light and >faded into a darkening orange, then black and was gone. It almost seemed >like the Carson Range was lighted slightly by the event, then went back >to its normal moon-lit mountain range at the night. > >Time: about 9:45 p.m. PST November 15 > >I had never seen anything like that before! It was huge, whatever it >was. > >--=20 >---/---- >Charles P. Watson, Consulting Geologist >Advanced Geologic Exploration >Seismo-Watch / Earthquake Information Services >Voice: 702-852-0992 / Fax: 702-852-3226=20 >Office Location: 39.43N 119.71W >mailto:watson@................ >http://www.seismo-watch.com > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the=20 >message: leave PSN-L > > Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., =20 Green Is., Dunedin, =20 South Is.. New Zealand. =20 http://psn.quake.net/dave/home.htm =20 IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: Spring Material, etc. Date: Sat, 15 Nov 1997 23:54:36 -0800 At 02:40 AM 11/15/97 -0600, Roger Baker wrote: >I suspect that the reason that the fellow who asked about springs wants his >spring to be non-magnetic is that he wants to use a nearby magnet and coil >combination for a motion detection sensor, but do be aware that LEDs and >phototransistors in combination are very good down to nanometer >displacements and give a DC signal, and that capacitance micrometers are >the best of all. The main reason for using a non-magnetic material is to avoid sensitivity to external changing magnetic fields. I intend to use this in a force-feedback system so (as you say) natural period is not very important, and I intend to use a differential-capacitor displacement detector. Spring stability is important for the following reason: Since any difference between the force on the mass due to gravity and the force of the spring will be made up by the feedback system, there will usually be some magnetic field due to current in the feedback coil. This can hopefully be adjusted to near zero by adjusting the spring anchor, but any instability in the spring's force will result in more current being applied to the feedback coil, with an attendant susceptability of the system to external magnetic fields. Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: George Harris Subject: Re: Spring Material Date: Sun, 16 Nov 1997 00:34:07 +0000 Karl Cunningham wrote: > I'm still working on a vertical force-balance seismometer design and hope > to balance the acceleration of gravity with the use of a coil extension > spring supporting the mass. > > However, the requirements of this spring are pretty severe, or so it seems: > 1) Non-magnetic and 2) Good stability over time periods to a couple of > minutes. >> > Does anyone out there have any ideas or suggestions? One of the very best materials for non-magnetic high strength and high elastic limit springs is beryllium copper. It is a copper with a small amount of beryllium added. The optimum springs are formed when in the soft condition, then hardened by treating at about 600 degrees for an hour or two. The California Fine Wire Company in Grover Beach phone 805-498-5144 is a very good source, though small quantities may be expensive. They stock wire in various hardnesses. I have been using hardened beryllium copper wire in an attempt to make a two axis force balanced horizontal seismometer. Any good spring company will be familiar with the material. George Harris Carpinteria, CA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Joan Chesleigh-Blaine Subject: Re: Huge meteor...space junk Date: Sun, 16 Nov 1997 00:07:43 -0800 Charlie, The article you referenced is about the Friday night display seen in the PNW. Your light show is a new one! Joan Charles Watson wrote: > Well, good ol' CNN had a story up on their web site in less than 20 > minutes: > > http://www.cnn.com/TECH/9711/15/light.show.ap/index.html > > -- > ---/---- > Charles P. Watson, Consulting Geologist > Advanced Geologic Exploration > Seismo-Watch / Earthquake Information Services > Voice: 702-852-0992 / Fax: 702-852-3226 > Office Location: 39.43N 119.71W > mailto:watson@................ > http://www.seismo-watch.com > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ray Gallagher Subject: Re: Huge meteor...space junk Date: Sun, 16 Nov 1997 00:10:25 -0800 Hello Charlie, When did you see this? The CNN story was for an event on Friday the 14th at 9:09 p.m. to 9:15 p.m PT. Ray Charles Watson wrote: > Well, good ol' CNN had a story up on their web site in less than 20 > minutes: > > http://www.cnn.com/TECH/9711/15/light.show.ap/index.html > > -- > ---/---- > Charles P. Watson, Consulting Geologist > Advanced Geologic Exploration > Seismo-Watch / Earthquake Information Services > Voice: 702-852-0992 / Fax: 702-852-3226 > Office Location: 39.43N 119.71W > mailto:watson@................ > http://www.seismo-watch.com > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Huge meteor...space junk Date: Sun, 16 Nov 1997 00:39:24 -0700 I saw it this Saturday evening, November 15th at around 9:45 pm pst. Yeah, I went back to the cnn site and saw the report there was for Friday. Humm.. I called the local police station. They said they had a couple calls, but they had no info. It was like nothing I'd ever seen before. But the first thought I had after seeing the intense whiteness at the end of the streak was some space junk or something. No sounds, Dave. -- ---/---- Charles _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: James Subject: Re: Huge meteor...space junk Date: Sun, 16 Nov 1997 08:35:03 -0600 (CST) The Leonids meteor shower should start tomorrow, 11/17/97. http://www.skypub.com/meteors/leoking.html _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: PSN presentation at AGU Date: Sun, 16 Nov 1997 22:11:54 -0700 PSN Members- We are planning a presentation of the Public Seismic Network (PSN) at the 1997 Fall Meeting of the American Geophysical Union in San Francisco on 8-12 Dec 1997 . The PSN presentation will be made on Friday 12 Dec 1997. To see the abstract of the presentation, go to the webpage and look up the key words "Public Seismic Network". The presentation will include an online demonstration of the PSN websites. If you have any suggestions of what we should include, please email them to this PSN-L Mailing List. -Edward -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Taber Subject: Re: Seismology text books Date: Mon, 17 Nov 1997 19:25:08 +1300 (NZDT) > A question for academics, students and/or recent graduates in >seismology--What are the current seismology textbooks, either >beginning or advanced? We use "Modern Global Seismology" by Thorne Lay and Terry Wallace, Academic Press, 1995, for an introduction to seismology for 4th year undergraduates. It has lots of good current examples of research to go along with the theory. John Taber School of Earth Sciences Victoria University of Wellington _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Walt Williams" Subject: NW Fireball - Huge meteor...space junk Date: Mon, 17 Nov 1997 01:08:04 +0000 Friends, For those who either saw or have heard 'reports' regarding an Unidentified Object streaking around the skies in the Washington area. This is cross posted from the MeteorObs, North American Meteor Network list-serv, this could be related: Best Regards, Walt Williams, 97.11.14 dfheli@.............. Woodland Hills, (LA suburb), California USA ================================================== Date sent: Sun, 16 Nov 1997 17:07:52 -0500 To: Meteor Observers Mailing List From: Jim Bedient (by way of lewkaren@........ (Karen Simmons & Lew Gramer)) Subject: (meteorobs) (ams) NW Fireball Send reply to: meteorobs@........... There was a good sized fireball last night in the Seattle/Vancouver area. I've gotten 6 or 8 reports so far, and another 3-4 from Andre. Here's on of the more interesing ones, with a report of sound effects: >Date: Sat, 15 Nov 1997 04:24:29 -0500 >From: World Wide Web Account >To: meteors@......... >Subject: FORM RESULTS > >Form results from http://www.serve.com/meteors/form_1.html > >---------------- AA_Name >Jason Knight > >---------------- AA_Sender_Email >jknight@............ > >---------------- AB_Date >November 14-15 1997 > >---------------- AC_time >9:15 > >---------------- AD_am/pm >PM > >---------------- AE_Timezone >Pacific > >---------------- AF_Other_Timezone > > >---------------- AG_Type_time >Standard > >---------------- AH_Location >University of British Columbia Campus (Point Grey, Vancouver, B.C.) > >---------------- AI_Magnitude >-3 > >---------------- AK_Path_Length >Variable. Multiple Pieces, perhaps 10 degrees apart > >---------------- AL_Initial_Az > > >---------------- AM_Initial_Az_mag_or_true >Magnetic > >---------------- AN_Direction_First_Seen >W > >---------------- AO_Initial_Alt >unknown > >---------------- AP_Final_Azimuth > > >---------------- AQ_Final_Azimuth_mag_or_true >Magnetic > >---------------- AR_Direction_last_seen >E > >---------------- AS_Final_Altitude >0 (zero) > >---------------- AT_Overhead >Yes > >---------------- AU_Duration >greater than 10 sec > >---------------- AV_Color >Bright Orange, some white > >---------------- AW_Train >Yes > >---------------- AX_Train_Duration >>1 > >---------------- AY_Train_Duration_Units >minutes > >---------------- AZ_Train_Color >Orange, white > >---------------- BA_Train_Length >up to 10 degrees > >---------------- BB_Train_Remarks >I first saw the object as it was falling in the east; a group next >to me had been following the object from the west - The best >description was of firework ashes falling. There appeared to be two >main segments to the object, each breaking up into smaller orange >objects as it moved eastward. The debris appeared to be too long >lasting to anything but a fireball. The objects passed visibly below >my line of sight, without fading. > > >----------------BC_General_Remarks >At first I was uncertain as to whether this was >some sort of firework (I was looking over downtown Vancouver at the >time) or a meteor. It appeared to last far too long, however; but it >also seemed to be too slow moving to be a meteor. Perhaps a piece of >space debris (the Russian satellite that was to break up over Japan >yesterday, Nov. 13)? This would be more consistant with the breakup >seen. > > >Although I am not completely certain whether or not this is >connected to the object(s), approximately 1.5 to 2 minutes later I >could distinctly hear a series (5~7) of low claps/rumbles, similar >to thunder, but lower in frequency and different in modulation. The >sky was completely clear, and this could indicate an event within 20 >miles of my observing point. Sketchy radio reports within the last >hour seem to be confirming that parts of this fireball have struck >the ground within the Fraser Valley/ Northern Washington >(Abbotsford?). >I have been attempting to confirm this with others. > > > >---------------- next_page >/meteors/ty.html > > > ----------------------------------------------------------------- |James R. Bedient |E-Mail: james.bedient@............ |Traffic Management Coordinator | Fax: 808-739-7604 | |Federal Aviation Administration| Home: wh6ef@........ | |Honolulu CERAP |School: jamesbed@.......... | ----------------------------------------------------------------- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Charlie Rond Subject: Re: PSN presentation at AGU Date: Mon, 17 Nov 1997 02:51:12 -0600 Edward, >PSN Members- > We are planning a presentation of the Public Seismic Network (PSN) at >the 1997 Fall Meeting of the American Geophysical Union in San Francisco >on 8-12 Dec 1997 . The PSN >presentation will be made on Friday 12 Dec 1997. > To see the abstract of the presentation, go to the webpage > and look up the key words >"Public Seismic Network". > The presentation will include an online demonstration of the PSN >websites. If you have any suggestions of what we should include, please >email them to this PSN-L Mailing List. Congratulations on the opportunity to present the PSN story at the AGU meeting! Let me know anything I can do to help. Charlie Rond -\/\--Public Seismic Network-Memphis rond@................ (901) 360-0302 [ free BBS ] http://gandlf.ceri.memphis.edu/~rond http://gandlf.ceri.memphis.edu/~rond/psn _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Seismology text books Date: Tue, 18 Nov 1997 00:04:28 +1200 Bob, this excellent title I have posted here before it is also in wide use in this part of the world The Solid Earth, An Introduction to Global Geophysics. by C.M.R. Fowler Cambridge University Press, reprinted 1992 ISBN 0-521-38590-3 soft cover ISBN 0-521-37025-6 hard cover it covers many geophysics subjects including plant tectonics/motions earth's magnetic field seismic wave propagation, seismology, reflection/refraction seismology gravity/anomalies mantle viscosity radiometric dating...uranium-lead, potassiun-argon etc heat flow, conductive/convective ridges,trenches,transform faults it is a required textbook for 2nd and 3rd at Otago University here in Dunedin where I study Dave At 07:25 PM 11/17/97 +1300, you wrote: >> A question for academics, students and/or recent graduates in >>seismology--What are the current seismology textbooks, either >>beginning or advanced? Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: PSN presentation at AGU Date: Mon, 17 Nov 1997 06:52:55 -0700 Great job, Ed! I've got some business in the Bay Area and shedualed it so I could go at least one day at AGU, unfortunately Mon, Tues or Wed, so I'll miss the PSN demo. Maybe we could have coffee together. Love to place a face with the words. -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: PSN presentation at AGU Date: Mon, 17 Nov 1997 13:21:12 -0700 Charles- At this point, I plan to be at AGU on Monday & Tuesday, but then I will go down and work with Larry Cochrane until the presentation on Friday morning. So maybe we could get together Monday or Tuesday. -Edward PS. You will be able to see some of the demo on the web. Charles Watson wrote: > > Great job, Ed! > > I've got some business in the Bay Area and shedualed it so I could go at > least one day at AGU, unfortunately Mon, Tues or Wed, so I'll miss the > PSN demo. > > Maybe we could have coffee together. Love to place a face with the > words. > > -- > ---/---- > Charles P. Watson, Consulting Geologist > Advanced Geologic Exploration > Seismo-Watch / Earthquake Information Services > Voice: 702-852-0992 / Fax: 702-852-3226 > Office Location: 39.43N 119.71W > mailto:watson@................ > http://www.seismo-watch.com > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: PSN presentation at AGU Date: Mon, 17 Nov 1997 12:28:06 -0700 Monday and Tuesday sound fine. I'll check the schedule and get back with you for a java moment. -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: ACole65464@....... Subject: test test test Date: Mon, 17 Nov 1997 20:24:43 -0500 (EST) test _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: AOL users unable to post on the Listserver Date: Mon, 17 Nov 1997 20:29:41 -0700 Hi Allan and Others, I'm not sure what's going on.... This seems to be a problem only with AOL. The mail server I have has a watch program for monitoring the activity of the server. I can seen the AOL message coming in but never completing. AOL gets to the point where it should start sending the text part of the message but never does. My system sits there waiting for AOL to send the text and then times out. The strange thing is that AOL users can send email to me at cochrane@............... Webtroncs.com and psn.quake.net are the same system. Since mail to webtronics.com seems to work, AOL users should send mail to this list using PSN-L@.............. instead of the psn.quake.net address. Hopefully that will work. If it doesn't please let me know. Regards, Larry Cochrane Redwood City, PSN At 09:38 PM 11/17/97 -0500, you wrote: >Larry, > >Can you see why I am unable to post messages to "psn-l@.............", I have >used this address in the past with no problem. I have sent several postings >over the last couple of weeks but they have not appeared. Can you help me? > >Thanks, > >Allan Coleman > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Donald Sieber Subject: AOL Date: Mon, 17 Nov 1997 21:06:49 -0800 Aol seems to be having difficulties sending e-mail depending on the point of origin and the size of the file. My long messages would start sending and then for some reason the transmission rate would slow to a standstill and then time out. Some relatives on the East coast don't seem to have this problem with AOL. My solution, find a new internet provider. Don Larry wrote...................................................... Hi Allan and Others, I'm not sure what's going on.... This seems to be a problem only with AOL. The mail server I have has a watch program for monitoring the activity of the server. I can seen the AOL message coming in but never completing. AOL gets to the point where it should start sending the text part of the message but never does. My system sits there waiting for AOL to send the text and then times out. The strange thing is that AOL users can send email to me at cochrane@............... Webtroncs.com and psn.quake.net are the same system. Since mail to webtronics.com seems to work, AOL users should send mail to this list using PSN-L@.............. instead of the psn.quake.net address. Hopefully that will work. If it doesn't please let me know. Regards, Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Question about a geotech seismometer Date: Mon, 17 Nov 1997 23:45:00 -0700 (MST) Hello Everybody, I have been dusting off an old Geotech horizontal seismometer and was wondering if anyone might have information or possibly even a manual around for this device. Here is a quick description: It is a Lehman type with a large solid brass mass with two pick-up coils on either side going into metal cylinders which I assume are magnetic. The boom and mass are one piece, and are supported by two wires from the mass sides which are connected by a clamp to a single wire which hangs from a solid metal mast which extends out to either side of the boom in the shape of a "V". The boom rotates on some kind of hidden hinge or something in the cradle of the mast. The whole deal sits on a triangular plate with three adjusting feet at its corners. There is a nice metal cover that fits nicely over the seismometer as well. I have come across a problem with this device. There is a definite torsional vibration along the boom. This will have the effect of making the coils go up and down inside the magnets like the arms of somebody doing a balancing act. The last person to operate this seismometer said that it "wigged out" and did wierd things during events, and I believe this is the culprit. The problem then is to eliminate this vibration somehow. I don't believe the instrument was designed with this flaw, as it is well-designed in every other aspect. I at first wondered if the boom rotated on two sharp pins so that stretching of the supporting wires would cause the upper pin to lose contact. After raising and lowering the wires I found that this was probably not the problem. The only other things I can think of is a blade or leaf spring type of rotating support. Therefore, before tearing it all apart I am trying to find somebody who may know this device that can tell me a little bit about it first. So if anyone knows, please reply!!! ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: PSN at the AGU and N.Cal PSN meeting! Date: Mon, 17 Nov 1997 23:22:34 -0700 Hi Everyone, I talked to Edward C. last night. As part of the demonstration for the AGU meeting we will be setting up a SDR and WinQuake system(s?). I would also like to show some sensors that we are using. A Lehman is too large so I was thinking about showing one of my SG sensors. If someone local has a homemade sensor that they can bring by, please let me know. We don't have a lot of room so it will need to be small. Since Edward will be staying out here the following week (12/14 to 12/21) we where taking about setting up a PSN meeting. I have been wanting to have a meeting for some time now but have been waiting until Edward could be here. So it looks like Saturday, December 20 would be a good time for the meeting, and, I think we will be able to use a conference room at the Menlo Park USGS. I was think of starting the meeting around 11:00AM. That way people who may have a long drive won't have to get up to early on a Saturday. Since we should be able too have the conference room all day we could end around 4 to 5Pm, or sooner if we run out of things to talk about. Since the meeting would be around lunch time maybe we could have it catered or order pizza. At this point things are a little tentative. What I would like to know is how many people would like to come. So if you could RSVP me at cochrane@.............. that would be great. As we get closer to the event I will update my web site with info about the meeting and map showing how to get to the Menlo Park USGS. I will also announce the meeting on several Internet News groups so we can get new people into the group. I'm also looking for input on how the meeting should be run. Depending on how many people plan to attend we can make if very informal to a more formal event. I'm also looking for help on organize the event. If you would like to help please call me at 650.365.7162 or email me. Regards, Larry Cochrane Redwood City, PSN >PSN Members- > We are planning a presentation of the Public Seismic Network (PSN) at >the 1997 Fall Meeting of the American Geophysical Union in San Francisco >on 8-12 Dec 1997 . The PSN >presentation will be made on Friday 12 Dec 1997. > To see the abstract of the presentation, go to the webpage > and look up the key words >"Public Seismic Network". > The presentation will include an online demonstration of the PSN >websites. If you have any suggestions of what we should include, please >email them to this PSN-L Mailing List. >-Edward > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Question about a geotech seismometer Date: Tue, 18 Nov 1997 23:57:56 +1200 John, Thats a Press-Ewing type seismometer I hope to have my one running over the next month or so I have to pour a concrete pad for it to sit on. They were manufactured by several different companies my one came from Sprengnether. A week or so back someone on this mail list wanted to find good homes for 6 or so.... may have been Ed Cranswick on behalf of the owner. The seismometer is used worldwide as part of the WWSSN (worldwide standard seismic network) I do own a manual to set up one of these beasts if you cannot get one from someone in the USA send me a postal address and I will get a copy off to you. Dave At 11:45 PM 11/17/97 -0700, you wrote: >Hello Everybody, > > I have been dusting off an old Geotech horizontal seismometer and was >wondering if anyone might have information or possibly even a manual >around for this device. > > Here is a quick description: It is a Lehman type with a large solid >brass mass with two pick-up coils on either side going into metal >cylinders which I assume are magnetic. The boom and mass are one piece, >and are supported by two wires from the mass sides which are connected by >a clamp to a single wire which hangs from a solid metal mast which >extends out to either side of the boom in the shape of a "V". The boom >rotates on some kind of hidden hinge or something in the cradle of the >mast. The whole deal sits on a triangular plate with three adjusting >feet at its corners. There is a nice metal cover that fits nicely over >the seismometer as well. > > I have come across a problem with this device. There is a definite >torsional vibration along the boom. This will have the effect of making >the coils go up and down inside the magnets like the arms of somebody >doing a balancing act. The last person to operate this seismometer said >that it "wigged out" and did wierd things during events, and I believe >this is the culprit. The problem then is to eliminate this vibration >somehow. I don't believe the instrument was designed with this flaw, as >it is well-designed in every other aspect. I at first wondered if the >boom rotated on two sharp pins so that stretching of the supporting wires >would cause the upper pin to lose contact. After raising and lowering >the wires I found that this was probably not the problem. The only other >things I can think of is a blade or leaf spring type of rotating >support. > > Therefore, before tearing it all apart I am trying to find somebody >who may know this device that can tell me a little bit about it first. >So if anyone knows, please reply!!! > >****************************************************************************** > > John Hernlund > E-mail: hernlund@....... > WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ > >****************************************************************************** > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Darrell Collins Subject: Re: Question about a geotech seismometer Date: Tue, 18 Nov 1997 07:36:16 -0700 At 11:45 PM 11/17/97 -0700, you wrote: >Hello Everybody, > > I have been dusting off an old Geotech horizontal seismometer and was >wondering if anyone might have information or possibly even a manual >around for this device. > John, I also have a man on the geotech horiz. I'll send it in school mail if you'll give me your Mesa CC address. Darrell _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: Question about a geotech seismometer Date: Tue, 18 Nov 1997 14:48:29 +0000 John Hernlund wrote: > ........................................ > > I have been dusting off an old Geotech horizontal seismometer and was > wondering if anyone might have information or possibly even a manual > around for this device. > Therefore, before tearing it all apart I am trying to find somebody > who may know this device that can tell me a little bit about it first. > So if anyone knows, please reply!!!................................ Hi John, Someone on PSN has already told you that above is a Press-Ewing job.....if it's any help, I have a photo of this instrument in a seismo book of mine, AND, it makes the point that this instrument is used INSIDE a strong airtight metal case to protect against barometric changes! ALSO, it is contained within an outer cover of polystyrene, and operated at 15-30 sec periods. They are used by WWSN together with their vertical counterparts. It also mentions that special attention has been paid in their design to long term stability, and also to elimination of FALSE RESONANCES, caused by the spring of the vert component. Regards, Albert Noble (England). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Marnie Gannon Subject: Greek 6.6 Date: Tue, 18 Nov 1997 09:48:41 -0700 Just noticed NEIC reports a 6.6 quake in Greece at: 97/11/18 13:07:41 37.32N 21.01E 33.0 6.4Ms B SOUTHERN GREECE the preliminary IDC list shows several since then throughout the area. (note:idc locations are unreviewed and will show smaller magnitudes.) Looks like the 5.9 and 5.4 might be one event. NOTE: These are unreviewed automatic locations and should be used with great caution B Date Time Lat Lon Nph Depth Mag Region a 1997/11/18 14:28:30.8 37.35N 21.56E 14 52.1 mb 3.9 Southern Greece a 1997/11/18 14:25:24.5 37.39N 21.22E 26 mb 4.2 Southern Greece a 1997/11/18 14:03:40.3 37.94N 22.05E 17 34.1 mb 3.9 Southern Greece a 1997/11/18 13:56:37.4 38.31N 20.41E 34 87.1 mb 4.1 Greece a 1997/11/18 13:56:16.4 36.96N 20.60E 11 mb 4.0 Central Mediterranean Sea a 1997/11/18 13:44:07.7 37.49N 20.68E 29 41.5 mb 4.3 Ionian Sea a 1997/11/18 13:33:19.5 30.16S 48.15W 10 mb 4.1 South Atlantic Ocean a 1997/11/18 13:31:19.2 38.52N 21.45E 13 mb 4.1 Greece a 1997/11/18 13:22:47.1 37.47N 20.99E 52 mb 4.6 Ionian Sea a 1997/11/18 13:13:44.1 37.44N 21.14E 51 mb 5.1 Southern Greece a 1997/11/18 13:07:53.1 34.49N 21.65E 10 mb 5.9 Central Mediterranean Sea a 1997/11/18 13:07:37.9 37.48N 20.69E 74 mb 5.4 Ionian Sea Marnie Gannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: I want to visit the PSN in Denver Date: Tue, 18 Nov 1997 10:43:16 -0700 Meredith- Since you are right next door to USGS, Golden, I would like to visit you and see your seismograph setup. Please let me know where I can call you. -Edward -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: Concrete foundations and DECOUPLING Date: Tue, 18 Nov 1997 11:42:55 -0700 Albert- That is a very insightful observation you have made about the decoupling effects and response characteristics of the concrete block, i.e., pier (traditional seismo terminology), on which you have mounted your seismograph. In effect, the "cherry on jelly" will act to shock-mount the seismometer. It will function as a damped harmonic oscillator with the block acting as the mass and the supporting soil acting as the spring and damping. The pier will have a flat response to ground motion, i.e., its motion will follow or accurately reflect ground motion, at low frequencies; it will resonate to a greater or lesser degree at its natural frequency; at frequencies higher than that frequency, its response will decay at 12 dB/octave, or its amplitude will diminish by a factor of 4 for every doubling of frequency. In other words, the response of the pier will be the reciprocal of the response of a seismometer: the former is said to have a flat response when there is a minimum of differential motion between the inertial frame (the mass) and the reference frame (the Earth), and the latter has a flat response when there is a maximum of differential motion between the inertial and reference frames. I have never quite thought about this matter before in these terms, and as such, it is somewhat paradoxical at first. Piers will act as low-pass filters to filter out footsteps and other high frequencies, but they can also exhibit very strong resonances that introduce pathological large-amplitude high-frequencies. I saw this latter effect in Armenia when we deployed our strong motion accelerometers and portable seismographs on piers built by the Soviets for long-period seismographs. -Edward prewar wrote: > > Hello, > I see from list of PSN sites that many have large concrete > blocks upon which the seismos are fixed. I too have a heavy > concrete block, 2ft long x 1.5 ft wide x 2ft DEEP. The block is > FLUSH with the ground surface, but ONLY the bottom 6 inches > of the block is in contact with the ground. (It is pinned into the > ground with 3/4 dia steel driven into earth at bottom last 6 inches). > > My reason for doing this was to decouple the block from any earth > movements at ground level.......footsteps, SMALL roots of hedges > and trees etc. > > I am now rather concerned that being situated on clay, then the > inertia of a 1/5th ton block will not allow it to move as the earth > beneath does. Should I 'fill in' the top 18 inches and ensure that > ALL the block is in direct contact with earth or not ?? Will the > block be decoupled and act as a cherry on top of jelly if I don't? > > If anyone with concrete blocks has considered above I would > like to know of their experiences, and what they did. Thanks. > > Regards, > > Albert Noble (England). > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: MLamb12830@....... Subject: test only Date: Tue, 18 Nov 1997 13:48:47 -0500 (EST) test only of AOL problem. Thanks _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: MLamb12830@....... Subject: Test of high case PSN-L@............. v/s psn-l@............. Date: Tue, 18 Nov 1997 13:54:55 -0500 (EST) Test for higher case only. Thanks. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: MLamb12830@....... Subject: Correction Date: Tue, 18 Nov 1997 14:36:42 -0500 (EST) Hi group, First and foremost a correction: It was Larry Cochranes case sensitve letter that solved my AOL problem. Thanks Larry! Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: Concrete foundations and DECOUPLING Date: Tue, 18 Nov 1997 19:43:45 +0000 Hello Edward, Thanks for your very erudite analysis of my, 'cherry on a jelly'.... (There's much more to this seismology than, in my beginners innocence, I first imagined!!). I think I follow all your reasoning on this, and that concrete could be made to, 'ring', if hit, and this would be the resonance you refer to. My seismos will be bolted to 1" sq section steel, and bolted into block, (sorry, 'pier'. ). So these steel bars will ALSO have their own resonant frequencies to ,'add to the general tormoil'. I hope that somewhere under it all, I shall one day, be able to detect a few ,'quakes' . Thanks again for help. I shall go ahead now and complete. Regards, Albert Noble (England). Edward Cranswick wrote: ................................ > .....decoupling effects and response characteristics of the concrete block, > i.e., pier (traditional seismo terminology), on which you have mounted > your seismograph. In effect, the "cherry on jelly" will act to > shock-mount the seismometer. It will function as a damped harmonic > oscillator with the block acting as the mass and the supporting soil > acting as the spring and damping. The pier will have a flat response to > ground motion, i.e., its motion will follow or accurately reflect ground > motion, at low frequencies; it will resonate to a greater or lesser > degree at its natural frequency; at frequencies higher than that > frequency, its response will decay at 12 dB/octave, or its amplitude > will diminish by a factor of 4 for every doubling of frequency. In > other words, the response of the pier will be the reciprocal of the > response of a seismometer: the former is said to have a flat response > when there is a minimum of differential motion between the inertial > frame (the mass) and the reference frame (the Earth), and the latter has > a flat response when there is a maximum of differential motion between > the inertial and reference frames. I have never quite thought about > this matter before in these terms, and as such, it is somewhat > paradoxical at first. > Piers will act as low-pass filters to filter out footsteps and other > high frequencies, but they can also exhibit very strong resonances that > introduce pathological large-amplitude high-frequencies. I saw this > latter effect in Armenia when we deployed our strong motion > accelerometers and portable seismographs on piers built by the Soviets > for long-period seismographs. > -Edward > > prewar wrote: > > > > Hello, > > I see from list of PSN sites that many have large concrete > > blocks upon which the seismos are fixed. I too have a heavy > > concrete block, 2ft long x 1.5 ft wide x 2ft DEEP. The block is > > FLUSH with the ground surface, but ONLY the bottom 6 inches > > of the block is in contact with the ground. (It is pinned into the > > ground with 3/4 dia steel driven into earth at bottom last 6 inches). > > > > My reason for doing this was to decouple the block from any earth > > movements at ground level.......footsteps, SMALL roots of hedges > > and trees etc. > > > > I am now rather concerned that being situated on clay, then the > > inertia of a 1/5th ton block will not allow it to move as the earth > > beneath does. Should I 'fill in' the top 18 inches and ensure that > > ALL the block is in direct contact with earth or not ?? Will the > > block be decoupled and act as a cherry on top of jelly if I don't? > > > > If anyone with concrete blocks has considered above I would > > like to know of their experiences, and what they did. Thanks. > > > > Albert Noble (England). > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: New Addition Date: Tue, 18 Nov 1997 13:11:59 -0700 Meredith- I am looking forward to meeting you in person. -Edward David A. Nelson wrote: > > hi ya 'll, > please welcome our latest newcomer to the group map and > database. Meredith Lamb, who hails from Denver, Colorado. > > Chow > Dave > > Co-ordinator: > New Zealand > Public Seismic Network > Dave A. Nelson ZL4TBN > 24 Jensen St., > Green Is., Dunedin, > South Is.. New Zealand. > > http://psn.quake.net/dave/home.htm > > IF there indeed are other parallel universes... I can now rest in the > knowledge, that in at least one of them, I am filthy rich and drive a red > Ferrari > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: Concrete foundations and DECOUPLING Date: Tue, 18 Nov 1997 13:18:31 -0700 Albert- I forgot to mention that within the field of seismic engineering, the response of a seismic pier, a block in soil, to ground motions would be considered a problem of "soil/structure interaction" and that is a very important concern when designing buildings to be seismically resistant. -Edward > > prewar wrote: > > > > > > Hello, > > > I see from list of PSN sites that many have large concrete > > > blocks upon which the seismos are fixed. I too have a heavy > > > concrete block, 2ft long x 1.5 ft wide x 2ft DEEP. The block is > > > FLUSH with the ground surface, but ONLY the bottom 6 inches > > > of the block is in contact with the ground. (It is pinned into the > > > ground with 3/4 dia steel driven into earth at bottom last 6 inches). > > > > > > My reason for doing this was to decouple the block from any earth > > > movements at ground level.......footsteps, SMALL roots of hedges > > > and trees etc. -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Dennis Eckert" Subject: Any Washington State folks? Date: Tue, 18 Nov 1997 13:27:26 -0800 Are there any Washington State folks on this list? Especially, the Puget Sound area (Everett, Snohomish, et al). I've just received a great E-mail from the UWashington which details their sites maps for monitoring radio transmissions, and wondered if someone in my area with similar interests to share and learn together. It includes frequencies used and how they link the sites along with the site locations. Dennis Eckert KB7ST (Amateur Radio Operator) Flies Standard Cirrus sailplane (SV) In Western & Eastern Washington ICQ 4324132 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: Question about a geotech seismometer Date: Tue, 18 Nov 1997 14:41:27 -0700 (MST) On Tue, 18 Nov 1997, David A. Nelson wrote: > They were manufactured by several different companies my one came from > Sprengnether. A week or so back someone on this mail list wanted to find > good homes for 6 or so.... may have been Ed Cranswick on behalf of the owner. That is good. If anyone still is looking for a home for one of them I have a good place! At Arizona State University we have a vertical and a horizontal component, and I would love to have a third component in addition to these. The two we have were once a part of a station here in Phoenix at a place called Mummy Mountain. The Geology department has since used them to interest people walking around in our physical Science complex. I am installing a computer with Larry's electronics to get them running again and bought an extra channel in the hope of adding a third component one day... They will be used to generate interest in seismology at this school (a discipline which is not stressed at this AZ university which I hope to change). If whoever has some of these to donate still has one available and feels that this is a noble purpose and use please contact me! > > > > I have been dusting off an old Geotech horizontal seismometer and was > >wondering if anyone might have information or possibly even a manual > >around for this device. > > > > Here is a quick description: It is a Lehman type with a large solid > >brass mass with two pick-up coils on either side going into metal > >cylinders which I assume are magnetic. The boom and mass are one piece, > >and are supported by two wires from the mass sides which are connected by > >a clamp to a single wire which hangs from a solid metal mast which > >extends out to either side of the boom in the shape of a "V". The boom > >rotates on some kind of hidden hinge or something in the cradle of the > >mast. The whole deal sits on a triangular plate with three adjusting > >feet at its corners. There is a nice metal cover that fits nicely over > >the seismometer as well. > > > > I have come across a problem with this device. There is a definite > >torsional vibration along the boom. This will have the effect of making > >the coils go up and down inside the magnets like the arms of somebody > >doing a balancing act. The last person to operate this seismometer said > >that it "wigged out" and did wierd things during events, and I believe > >this is the culprit. The problem then is to eliminate this vibration > >somehow. I don't believe the instrument was designed with this flaw, as > >it is well-designed in every other aspect. I at first wondered if the > >boom rotated on two sharp pins so that stretching of the supporting wires > >would cause the upper pin to lose contact. After raising and lowering > >the wires I found that this was probably not the problem. The only other > >things I can think of is a blade or leaf spring type of rotating > >support. > > > > Therefore, before tearing it all apart I am trying to find somebody > >who may know this device that can tell me a little bit about it first. > >So if anyone knows, please reply!!! > > > >****************************************************************************** > > > > John Hernlund > > E-mail: hernlund@....... > > WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ > > > >****************************************************************************** > > > > > >_____________________________________________________________________ > > > >Public Seismic Network Mailing List (PSN-L) > > > >To leave this list email listserver@............. with the body of the > >message: leave PSN-L > > > > > > Co-ordinator: > New Zealand > Public Seismic Network > Dave A. Nelson ZL4TBN > 24 Jensen St., > Green Is., Dunedin, > South Is.. New Zealand. > > http://psn.quake.net/dave/home.htm > > IF there indeed are other parallel universes... I can now rest in the > knowledge, that in at least one of them, I am filthy rich and drive a red > Ferrari > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L > ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: New Ca map Date: Tue, 18 Nov 1997 14:53:23 -0700 Dave- I also think the new California PSN map looks great -- just in time for all those Californians who will show up at the PSN AGU presentation. I am slow responding to a backlog of PSN correspondence that took place during the two weeks I was out of the office. One of these days I hope to get you some more info about the quieting effects of going downhole. -Edward Larry Cochrane wrote: > > Looks great Dave! Thanks.... > > -Larry > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Greek 6.6 Date: Wed, 19 Nov 1997 13:04:23 +1200 Marnie, there has definately been 3 events in the sthrn greece region 1 of which was in the Ionian Sea Dave At 09:48 AM 11/18/97 -0700, you wrote: >Just noticed NEIC reports a 6.6 quake in Greece at: >97/11/18 13:07:41 37.32N 21.01E 33.0 6.4Ms B SOUTHERN GREECE > >the preliminary IDC list shows several since then throughout the area. >(note:idc locations are unreviewed and will show smaller magnitudes.) >Looks like the 5.9 and 5.4 might be one event. > > >NOTE: These are unreviewed automatic locations and should be used with >great caution > >B Date Time Lat Lon Nph Depth Mag Region >a 1997/11/18 14:28:30.8 37.35N 21.56E 14 52.1 mb 3.9 Southern >Greece >a 1997/11/18 14:25:24.5 37.39N 21.22E 26 mb 4.2 Southern >Greece >a 1997/11/18 14:03:40.3 37.94N 22.05E 17 34.1 mb 3.9 Southern >Greece >a 1997/11/18 13:56:37.4 38.31N 20.41E 34 87.1 mb 4.1 Greece >a 1997/11/18 13:56:16.4 36.96N 20.60E 11 mb 4.0 Central >Mediterranean Sea >a 1997/11/18 13:44:07.7 37.49N 20.68E 29 41.5 mb 4.3 Ionian Sea >a 1997/11/18 13:33:19.5 30.16S 48.15W 10 mb 4.1 South >Atlantic Ocean >a 1997/11/18 13:31:19.2 38.52N 21.45E 13 mb 4.1 Greece >a 1997/11/18 13:22:47.1 37.47N 20.99E 52 mb 4.6 Ionian Sea >a 1997/11/18 13:13:44.1 37.44N 21.14E 51 mb 5.1 Southern >Greece >a 1997/11/18 13:07:53.1 34.49N 21.65E 10 mb 5.9 Central >Mediterranean Sea >a 1997/11/18 13:07:37.9 37.48N 20.69E 74 mb 5.4 Ionian Sea > >Marnie Gannon > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Mammoth Lakes Swarm Date: Tue, 18 Nov 1997 19:20:37 -0800 (PST) Hello All: I found the following paragraph in a publication put out by the Dept. of Conservation Division of Mines and Geology in Sacramento, CA. Circa 1994 Volcanoes and Earthquakes There are several places in the State where there is clear evidence or strong suggestion of a correlation between volcanic centers and faults. Some of these places include alignments of plug-domes or cinder cones in the Mt. Lassen area; the arcuate alignment of some 15 volcanic centers south of Mono Lake; and the location of the Red Mountain and Crater Mountain volcanic cones on the Owens Valley Fault Zone. Outside of California, Cerro Prieto, a Quarternary cone in Baja, California lies squarly athwart the Cerro Prieto Fault, which may possibly be an extension of the San Jacinto Fault Zone or an offset of the Imperial Fault Zone. Nowhere is the association between seismic activity and crustal deformation more dramatic than when partially molten rocks are emplaced into the EArth's crust (Hanks, 1985). As magma approaches the Earth's surface, earthquake swarms develop with rates of activity commonly exceeding 1,000 events per day. These earthquakes are the result of increasing heat in the surrounding rocks and increasing strain as volcanic magma pushes through them. As the neighboring rocks fracture, the strain is relieved by an elastic rebound mechanism and consequently the Earth "quakes." Many earthquake swarms culminate in volcanic eruptions-frequently in Hawaii, for example, and spectacularly as at Mount St. Helens. However, other earthquake swarms such as the Mammoth Lakes Swarms of the 1980s in Long Valley, California, have not as yet resulted in a volcanic eruption. Frank Condon mail to :frankcnd@.......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Which filter type is best? Date: Sun, 16 Nov 1997 18:23:31 +0000 Hi everyone, Have just been searching PSN archives for the word, 'filter', in an attempt to establish which type is the best to go for. 1...active filters using op amps. 2...capacitor IC filters (x50 filter cut off clocking required) 3...Digital signal processing DSP (I believe that 'winquake' has something like this built in ???) No. 2 seems to offer less circuit wiring for a given number of poles, but can these IC's be clocked at such slow speeds as will be required for, say, a .1 hertz filter? No. 3 requires a nifty piece of fast software, which I am prepared to do, BUT does anyone have the relevant maths (simple if possible and not in C!... .....I use basic + assembly language)? Have just bought a rather expensive book on DSP but it doesn't give information required. .. (It would seem that one has to take various proportions of the previous data i/p's and sum them, but do not know how these proportions relate to cut off frequency chosen for filtering.) Plenty has been said in archives about filters, so I don't wish to start it all up again. However, DSP does seem to be the way ahead now, so I wonder if anyone can suggest the best way forward, or even recommend another book for me to buy? (As it's getting near to Xmas, I might even persuade Father Xmas to buy it for me ) Regards, Albert Noble (England). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: Which filter type is best? Date: Wed, 19 Nov 1997 11:03:01 -0800 At 06:23 PM 11/16/97 +0000, Albert wrote: >Hi everyone, > Have just been searching PSN archives for the word, 'filter', >in an attempt to establish which type is the best to go for. >1...active filters using op amps. >2...capacitor IC filters (x50 filter cut off clocking required) >3...Digital signal processing DSP (I believe that 'winquake' >has something like this built in ???) Hi Albert -- #2 -- Yes, some of these filter chips can be clocked slowly in order to do very low frequency cutoffs. Check the data sheet on the particular part you are thinking of. Watch out though, all of these IC's I've seen have very little attuation at multiples of the clock frequency (sometimes at half the clock frequency too). This means you may need to either incorporate analog anti-aliasing filters or choose your clock frequency carefully to avoid multiples that include harmonics of the frequeny of your power mains. #3 -- I've seen articles in "Embedded Systems Programming", a monthly magazine published by Miller Freeman. see http://www.embedded.com A few years ago they had a down-to-earth multi-part series on implementing digital filtering. I think this magazine leans toward C, but the math is generic. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Phil Giannini" Subject: Which filter type is best Date: 19 Nov 1997 14:22:07 -0800 REGARDING Which filter type is best Hi Albert, I've been playing around with the Maxim MAX 291 which is an 8 pole filter having a X100 clock. It seems to work fairly well as long as you use an external clock to drive it. I found that the internal clock is quite unstable and thereby causing the output signal to become very noisy and practically unusable for our purpose. Also, I have to agree with something Larry Cochrane told me about this type of filter, that being it is okay for use on a 12bit system, but starts being a bit too noisy for use in a 16 bit system. I have a portable recording setup (12 bit) that I take to many different places here in California like the Geysers for example. Each location has its own particular source of background noise. I found that by making the clock frequency adjustable I can change the bandwidth to suit the environment, or in other words I can saw off some of the higher frequency stuff. I just use a 555 timer and feed it into the clock input of the MAX 291's. Hope this is some help in your decision. Phil SFN & Z _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: ACole65464@....... Subject: Re: Any Washington State folks? Date: Wed, 19 Nov 1997 21:27:17 -0500 (EST) Dennis, I live in Edmonds, Wa. I have been using radio telemetry for some years though not much lately, contact me at the above AOL address. Allan Coleman _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: Which filter type is best? Date: Wed, 19 Nov 1997 09:49:10 -0800 Hi Albert #3 - Digital filters are in two catagories: IIR(Infinite impulse response) and FIR(Finite impulse response). I currently run FIR in one of my acquisition programs(assembly or compiled basic works fine for me). FIR tends to be less sensitive, requiring more poles, but it is much more stable. The thing I like about digital filters is that you make the filter response look more like what you desire by numbers, where as with hardware filters you are more constrained by component sizes and hardware real estate.You can have several pass and reject bands to prescribed db levels in one filter. With current processor speeds digital filters are much more possible than several years ago. Also numbers don't change with time and temperature but components do. Plus if you want to change the filter there's no resoldering. You still need to account for the Niquist criteria with hardware filters since the data is converted to numbers(counts) before filtering. It takes some time to find literature on digital filters. The math in filter design is a little compilcated but the routines to run the filters are not. Barry P.S. I got a shareware filter design program a few years ago from a company called Monarch. If I can find it. >Karl Cunningham wrote: > > At 06:23 PM 11/16/97 +0000, Albert wrote: > >Hi everyone, > > Have just been searching PSN archives for the word, 'filter', > >in an attempt to establish which type is the best to go for. > >1...active filters using op amps. > >2...capacitor IC filters (x50 filter cut off clocking required) > >3...Digital signal processing DSP (I believe that 'winquake' > >has something like this built in ???) > > #3 -- I've seen articles in "Embedded Systems Programming", a monthly > magazine published by Miller Freeman. see http://www.embedded.com A few > years ago they had a down-to-earth multi-part series on implementing > digital filtering. I think this magazine leans toward C, but the math is > generic. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: Which filter type is best? Date: Wed, 19 Nov 1997 22:20:26 -0700 Barry- FIR filters work very well provided that there is no energy in the frequency band near their corner frequencies. These filters are acausal: they use information from the past and future inputs to create the current output. When there is significant energy at the corner frequency, one observes interesting effects like apparent seismic phases arriving before the P-wave. All physical processes, e.g., like the filtering effects of the Earth, are causal: current output is based only on current and past input. Causal filters are said to be realizable because they can be realized by physical systems as opposed to timeseries being processed forwards and backwards on a computer. FIR filters do not introduce phase shifts. IIR filters are causal and introduce phase shifts like all other processes in the physical world. -Edward barry lotz wrote: > > Hi Albert > #3 - Digital filters are in two catagories: IIR(Infinite impulse > response) and FIR(Finite impulse response). I currently run FIR in one > of my acquisition programs(assembly or compiled basic works fine for > me). FIR tends to be less sensitive, requiring more poles, but it is > much more stable. The thing I like about digital filters is that you > make the filter response look more like what you desire by numbers, > where as with hardware filters you are more constrained by component > sizes and hardware real estate.You can have several pass and reject > bands to prescribed db levels in one filter. With current processor > speeds digital filters are much more possible than several years ago. > Also numbers don't change with time and temperature but components do. > Plus if you want to change the filter there's no resoldering. You still > need to account for the Niquist criteria with hardware filters since the > data is converted to numbers(counts) before filtering. It takes some > time to find literature on digital filters. The math in filter design is > a little compilcated but the routines to run the filters are not. > > Barry > P.S. I got a shareware filter design program a few years ago from a > company called Monarch. If I can find it. > > >Karl Cunningham wrote: > > > > At 06:23 PM 11/16/97 +0000, Albert wrote: > > >Hi everyone, > > > Have just been searching PSN archives for the word, 'filter', > > >in an attempt to establish which type is the best to go for. > > >1...active filters using op amps. > > >2...capacitor IC filters (x50 filter cut off clocking required) > > >3...Digital signal processing DSP (I believe that 'winquake' > > >has something like this built in ???) > > > > > #3 -- I've seen articles in "Embedded Systems Programming", a monthly > > magazine published by Miller Freeman. see http://www.embedded.com A few > > years ago they had a down-to-earth multi-part series on implementing > > digital filtering. I think this magazine leans toward C, but the math is > > generic. > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: Concrete foundations and DECOUPLING Date: Wed, 19 Nov 1997 23:32:23 -0700 (MST) Edward, So basically a shorter, wider, pier made of the stiffest cement should work out the best (such a design should increase the natural frequency)??? On Tue, 18 Nov 1997, Edward Cranswick wrote: > Albert- > That is a very insightful observation you have made about the > decoupling effects and response characteristics of the concrete block, > i.e., pier (traditional seismo terminology), on which you have mounted > your seismograph. In effect, the "cherry on jelly" will act to > shock-mount the seismometer. It will function as a damped harmonic > oscillator with the block acting as the mass and the supporting soil > acting as the spring and damping. The pier will have a flat response to > ground motion, i.e., its motion will follow or accurately reflect ground > motion, at low frequencies; it will resonate to a greater or lesser > degree at its natural frequency; at frequencies higher than that > frequency, its response will decay at 12 dB/octave, or its amplitude > will diminish by a factor of 4 for every doubling of frequency. In > other words, the response of the pier will be the reciprocal of the > response of a seismometer: the former is said to have a flat response > when there is a minimum of differential motion between the inertial > frame (the mass) and the reference frame (the Earth), and the latter has > a flat response when there is a maximum of differential motion between > the inertial and reference frames. I have never quite thought about > this matter before in these terms, and as such, it is somewhat > paradoxical at first. > Piers will act as low-pass filters to filter out footsteps and other > high frequencies, but they can also exhibit very strong resonances that > introduce pathological large-amplitude high-frequencies. I saw this > latter effect in Armenia when we deployed our strong motion > accelerometers and portable seismographs on piers built by the Soviets > for long-period seismographs. > -Edward > > prewar wrote: > > > > Hello, > > I see from list of PSN sites that many have large concrete > > blocks upon which the seismos are fixed. I too have a heavy > > concrete block, 2ft long x 1.5 ft wide x 2ft DEEP. The block is > > FLUSH with the ground surface, but ONLY the bottom 6 inches > > of the block is in contact with the ground. (It is pinned into the > > ground with 3/4 dia steel driven into earth at bottom last 6 inches). > > > > My reason for doing this was to decouple the block from any earth > > movements at ground level.......footsteps, SMALL roots of hedges > > and trees etc. > > > > I am now rather concerned that being situated on clay, then the > > inertia of a 1/5th ton block will not allow it to move as the earth > > beneath does. Should I 'fill in' the top 18 inches and ensure that > > ALL the block is in direct contact with earth or not ?? Will the > > block be decoupled and act as a cherry on top of jelly if I don't? > > > > If anyone with concrete blocks has considered above I would > > like to know of their experiences, and what they did. Thanks. > > > > Regards, > > > > Albert Noble (England). > > > > _____________________________________________________________________ > > > > Public Seismic Network Mailing List (PSN-L) > > > > To leave this list email listserver@............. with the body of the > > message: leave PSN-L > > -- > Edward Cranswick Tel: 303-273-8609 > US Geological Survey, MS 966 Fax: 303-273-8600 > PO Box 25046, Federal Center cranswick@........ > Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L > ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Force of Lehman susp. wire Date: Thu, 20 Nov 1997 11:34:39 -0500 Hi gang, A question about the design of a Lehman seismometer has been in the bac= k of my mind for a long time and I finally got around to trying to answer i= t. The question :Is the stiffness (or bending force) of the suspension wire= shortening the period of the Lehman? Obviously, if the wire was 1/4" in= diameter it would make the period very short. I found equations in Mark's Mech. Eng. Handbook for the bending of a cantiliver beam. If E is Young's modulus (for steel about 27e6 psi.) and= the length of the beam is L then the deflection f at the end of the beam = is f =3D (W*L^3) / (3*E*I) where W is the force and I is the 'moment of inertia'. The moment of inertia for a round beam is I =3D 1/4*A*r^2 where A is th= e cross-sectional area and r is the radius. (I don't understand this 'mome= nt of inertia' but it seems to work. It seems funny that it has dimensions = of inches^3.) To see if this whole mess works, I clamped a piece of piano wire in a vise. The wire was 0.0456" in diameter and the free length was 6.3". A force of 50 grams deflected the end about 34 mm. With these values, the area is 0.00163 in^2, the I (moment of inertia) is 2.12e-7 in^3, W is 0.0= 92 lbs or 41 grams which agrees nicely with the observed 50 grams. (Please excuse the mixed units.) For my Lehman, the wire in 0.012" diameter and is 29.5" long. With the= se values, the calc. gives 1.44 milligrams force per inch of deflection. = (Answer in milligrams because I have a feeling for that unit.) I calculate that for my Lehman which has about 8 lbs. of lead at the en= d, a deflection of 1" requires 413 milligrams force when the period is 30= secs. A 16" period pendulum would require more force. This is 290 times the force required to bend the suspension wire so I conclude that the wire stiffness is negligible. I'm a physical chemist so I'm on rather shaky ground with this sort of calculation. I would greatly appreciate it if someone more familiar with= this sort of thing would check all this and point out where I have gone wrong. If the 1.44 milligrams/in is correct, it gives me some feeling for why = a Lehman is so sensitive to air currents since the deflection due to a 'qua= ke is MUCH smaller than 1"! Bob Barns = _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Which filter type is best? Date: Thu, 20 Nov 1997 11:54:55 -0500 Albert, I tried a switched capacitor filter and found it to be impossibly noisy= (with a 16 bit A/D) at low (around 0.1 Hz) freqs. At these low freqs., I= suspect that the tiny capacitors on the chip are very leaky. I use a 6-pole active filter with a knee at 0.08Hz. and find it very satisfactory for teleseismic events. For nearby events, this is probably= too low a cut-off. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: Concrete foundations and DECOUPLING Date: Thu, 20 Nov 1997 11:19:27 -0700 John- > So basically a shorter, wider, pier made of the stiffest cement should > work out the best (such a design should increase the natural > frequency)??? .... but that will increase your high-frequency noise from local sources. I work with 2 Hz geophones (seismometers) in watertight cases (Mark Products L22 3-component) usually, and burying the geophone in a hole 0.5 meter deep improves the coupling and the signal/noise, but that would be harder to do with a larger Lehman. I still have to research Dave Nelsons question of the how deep the hole should be. -Edward John Hernlund wrote: > > Edward, > So basically a shorter, wider, pier made of the stiffest cement should > work out the best (such a design should increase the natural > frequency)??? > > On Tue, 18 Nov 1997, Edward Cranswick wrote: > > > Albert- > > That is a very insightful observation you have made about the > > decoupling effects and response characteristics of the concrete block, > > i.e., pier (traditional seismo terminology), on which you have mounted > > your seismograph. In effect, the "cherry on jelly" will act to > > shock-mount the seismometer. It will function as a damped harmonic > > oscillator with the block acting as the mass and the supporting soil > > acting as the spring and damping. The pier will have a flat response to > > ground motion, i.e., its motion will follow or accurately reflect ground > > motion, at low frequencies; it will resonate to a greater or lesser > > degree at its natural frequency; at frequencies higher than that > > frequency, its response will decay at 12 dB/octave, or its amplitude > > will diminish by a factor of 4 for every doubling of frequency. In > > other words, the response of the pier will be the reciprocal of the > > response of a seismometer: the former is said to have a flat response > > when there is a minimum of differential motion between the inertial > > frame (the mass) and the reference frame (the Earth), and the latter has > > a flat response when there is a maximum of differential motion between > > the inertial and reference frames. I have never quite thought about > > this matter before in these terms, and as such, it is somewhat > > paradoxical at first. > > Piers will act as low-pass filters to filter out footsteps and other > > high frequencies, but they can also exhibit very strong resonances that > > introduce pathological large-amplitude high-frequencies. I saw this > > latter effect in Armenia when we deployed our strong motion > > accelerometers and portable seismographs on piers built by the Soviets > > for long-period seismographs. > > -Edward > > > > prewar wrote: > > > > > > Hello, > > > I see from list of PSN sites that many have large concrete > > > blocks upon which the seismos are fixed. I too have a heavy > > > concrete block, 2ft long x 1.5 ft wide x 2ft DEEP. The block is > > > FLUSH with the ground surface, but ONLY the bottom 6 inches > > > of the block is in contact with the ground. (It is pinned into the > > > ground with 3/4 dia steel driven into earth at bottom last 6 inches). > > > > > > My reason for doing this was to decouple the block from any earth > > > movements at ground level.......footsteps, SMALL roots of hedges > > > and trees etc. > > > > > > I am now rather concerned that being situated on clay, then the > > > inertia of a 1/5th ton block will not allow it to move as the earth > > > beneath does. Should I 'fill in' the top 18 inches and ensure that > > > ALL the block is in direct contact with earth or not ?? Will the > > > block be decoupled and act as a cherry on top of jelly if I don't? > > > > > > If anyone with concrete blocks has considered above I would > > > like to know of their experiences, and what they did. Thanks. > > > > > > Regards, > > > > > > Albert Noble (England). > > > > > > _____________________________________________________________________ > > > > > > Public Seismic Network Mailing List (PSN-L) > > > > > > To leave this list email listserver@............. with the body of the > > > message: leave PSN-L > > > > -- > > Edward Cranswick Tel: 303-273-8609 > > US Geological Survey, MS 966 Fax: 303-273-8600 > > PO Box 25046, Federal Center cranswick@........ > > Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". > > > > _____________________________________________________________________ > > > > Public Seismic Network Mailing List (PSN-L) > > > > To leave this list email listserver@............. with the body of the > > message: leave PSN-L > > > > ****************************************************************************** > > John Hernlund > E-mail: hernlund@....... > WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ > > ****************************************************************************** > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: Force of Lehman susp. wire Date: Thu, 20 Nov 1997 20:54:43 +0000 Robert L Barns wrote: > Hi gang, > A question about the design of a Lehman seismometer has been in the back > of my mind for a long time and I finally got around to trying to answer it. > The question :Is the stiffness (or bending force) of the suspension wire > shortening the period of the Lehman? Obviously, if the wire was 1/4" in > diameter it would make the period very short..........snip................... Hi Bob, I have experienced this same thing ! My Hor. Seiemos have very fine point suspension + 10 lbs lead weights ....(I did describe them some weeks ago for PSN when I first joined.) In attempting to get 60 sec. periods, (WITHOUT any electronic assistance!), I found that it was very difficult to get much over 30 secs, using .015 piano wire. So, I substituted two strands of 30 lbs fishing line JUST at top, near to anchorage point.....(line stretches somewhat, and small length reduces this). The line does not exhibit any stiffness at its anchorage as the piano wire does. It was because of this that I did mention on PSN at this time, (12th Oct), if anyone had used CARBON FIBRE for suspension.... what we need is strength WITHOUT any stiffness, (which piano wire has of course.). Now, I haven't had time to complete my experiments in any scientific manner, BUT, the fishing line enabled the swing time to be increased beyond that attained with piano wire. The reason why long swing periods are 'stiffness sensitive', are because the amont that the seismo mass rises, (gaining its potential energy as it does so), is so much smaller than that for shorter periods. I believe that because of this, the influence of the stiffness of piano wire becomes more marked. A 60 sec period with a 24" beam has but a rise of LESS than one millionth of an inch(!), for a side to side swing of .01"......(over here that represents quite a large excursion !). If piano wire is used, I think it would assist the swing if it was NOT firmly anchored, but allowed to 'roll', on its anchorage, so that it need NOT BEND at all. I intend to do more work on this,and will post if anything interesting comes up. I am in the process of visiting fishing tackle shops here, in order to find a superior line.... ........with this I hope to 'reel-in' a large 'quake . Regards, Albert Noble (England). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: type of filter Date: Thu, 20 Nov 1997 21:17:06 +0000 Hi, Thanks to, among others, Barry, Bob, Karl and Phil, for very useful advice re filters. PSN is the best thing since, 'sliced bread'...! Regards, Albert Noble (England). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: Force of Lehman susp. wire Date: Thu, 20 Nov 1997 15:15:03 -0600 I suspected that the bending wire would be a problem. So I designed my Lehman with a knife edge pivot at the top. Jim Hannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: Force of Lehman susp. wire Date: Thu, 20 Nov 1997 15:05:20 -0800 Hi all -- My $.02 on the subject ... I believe that the force exerted by the piano wire on the mass should be pretty close to linear with deflection. And I think the restoring force due to gravity is also proportional to the deflection divided by the effective length of the pendulum. Not to discount your experience, but if this is true it should be possible to adjust the level of the Lehman such that one effect cancels the other and infinite period is the result. (Assuming perfect mechanical stability of the structure too.) Given the difficulty in achieving periods longer than 20 or 30 seconds, I think there may be another explanation. I have noticed that some commercial seismometers use flexures instead of a knife edge for the lower pivot. Perhaps friction involved with a knife edge or point pivot is part of the problem. Two additional things lead me to suspect this: I once calculated the size of a pivot point required to allow reasonably unimpeded deflections of the mass on the scale of seismic detection, and the pivot point had to be sharpened to a few-nanometer-wide point! After this, I put a drop of oil on the pivot point of my FB seismometer, and it improved the hysteresis (tendency not to return to the same place after an event) by about 50:1. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Clark Wockner Subject: Re: Force of Lehman susp. wire Date: Thu, 20 Nov 1997 17:27:10 -0800 prewar wrote: > Albert: You may want to inquire about a fishing line called spider wire. It is for casting reels and the TV comercials show a guy pulling a tree out with it. (grin) Regards, Clark --Illinois _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Mark Wilson mark@.............." Subject: Re: Force of Lehman susp. wire Date: Thu, 20 Nov 1997 16:36:03 -0800 (PST) At first I used piano wire, then I used threaded cable from a plotter, After it broke, I tried spider wire... great stuff... man it's strong, does not stretch, very flexible, and is real easy to work with. Just don't use scissors to cut it.. It's been on mine for about 8 months now. Never had to adjust for stretch yet. Kmart.. 100 ft (or so) for 12 bucks. Best part of the deal is... with what is left over, you put on your pole and go fishing! On Thu, 20 Nov 1997, Clark Wockner wrote: > prewar wrote: > > Albert: > You may want to inquire about a fishing line called spider wire. > It is for casting reels and the TV comercials show a guy pulling a tree > out with it. (grin) > Regards, Clark --Illinois > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L > *********************************************************************** --- mark@.............. --- http://www.markwilson.com --- wilsonm@............ *********************************************************************** ** Pursuant to US Code, Title 47, Chapter 5, Subchapter II, '227, ** ** any and all nonsolicited commercial E-mail sent to this address ** ** is subject to a download and archival fee to be determined by ** ** the provider supplying the bandwidth and disk storage space. ** ** ** ** E-mailing denotes acceptance of these terms. ** *********************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Dennis Eckert" Subject: Re: Any Washington State folks? Date: Thu, 20 Nov 1997 22:50:44 -0800 Allan, Nice to hear from you....I'm pretty new to the group. Instead of building a seismometer, I wanted to see what I could do with monitoring radio freqs first. A guy at the U-W sent me a description of their radio system with frequencies. Then I use an FFT program to take a look...haven't really seen an event....have to pay the $30 for the shareware program so I can log to a file. I'm also into scanners, particularly the new data trunking systems being used now in King County, altho I live in Snohomish. I'd be happy to forward you the E-mail from the U-W if you'd like....I cleaned it up a bit and put into a MS Word 97 format. Can you take it that way? In not, can re-save as MS-DOS text file... Take care... Dennis Eckert KB7ST (Amateur Radio Operator) Flies Standard Cirrus sailplane (SV) In Western & Eastern Washington ICQ 4324132 -----Original Message----- From: ACole65464@....... To: psn-l@............. Date: Wednesday, November 19, 1997 6:35 PM Subject: Re: Any Washington State folks? >Dennis, > >I live in Edmonds, Wa. I have been using radio telemetry for some years >though not much lately, contact me at the above AOL address. > >Allan Coleman > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Al Allworth Subject: Re: Force of Lehman susp. wire Date: Fri, 21 Nov 1997 00:31:34 -0800 (PST) At 08:54 PM 11/20/97 +0000, you wrote: > > >Robert L Barns wrote: > >> Hi gang, >> A question about the design of a Lehman seismometer has been in the back >> of my mind for a long time and I finally got around to trying to answer it. >> The question :Is the stiffness (or bending force) of the suspension wire I might suggest attaching the wire to a hardened metal ring and using a knife edged support for the top pivot through the ring. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: Spring Material Date: Fri, 21 Nov 1997 08:20:43 -0800 PSNers -- To all who responded to my query about springs, my sincere thanks. I've received a wealth of information on the subject, and I am now ready to proceed. For those interested, I ordered some .094" music wire and 302 stainless spring wire. I'll practice with the music wire, then make a good one with the stainless. Although 302 stainless does not have perfect temperature characteristics as a spring, I'll give it a try. As with most of these things, when it gives problems, I'll try to improve on it. Again, thanks to all for the suggestions. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Re: Spring Material Date: Fri, 21 Nov 1997 09:00:31 >To all who responded to my query about springs, my sincere thanks. I've >received a wealth of information on the subject, and I am now ready to >proceed. Karl I didn't monitor the entire conversation but did anyone happen to sugest magnetic repulsion or hydralics. Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: Spring Material Date: Fri, 21 Nov 1997 10:32:02 -0800 Norman -- No, those suggestions weren't made. I have thought about magnetic repulsion some, but am trying to keep any magnetic materials off of the moving parts of the system as much as possible; to reduce the sensitivity to changing magnetic fields and moving ferromagnetic stuff in the area (cars on the street, etc.). Do you have any suggestions for magnetic repulsion that avoid these problems? What hydraulic ideas do you have? -- Karl At 09:00 AM 11/21/97, you wrote: > Karl > I didn't monitor the entire conversation but did anyone happen to sugest >magnetic repulsion or hydralics. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roger Baker Subject: Re: Spring Material Date: Fri, 21 Nov 1997 13:14:47 -0600 Friends, I have had recent experience with trying to build a system with magnetic repulsion to support the mass. This arrangement is quite easy to build and sensitive and can use a magnet and razor blade combination with a thermostatted enclosure (since magents generally weaken with rise in temperature). The problem is that the device is sensitive to both short range micropulsations as well as seismic disturbances, and magnetic shielding in not very easy to do. Merely putting it in an iron box is not good enough--you probably need multiple iron layers plus mu-metal (as PSN member Crice suggested some time back). Even so you will have a residual field, but it will be constant at least. I used two heavy nested sections of iron pipes and that wasn't good enough and mu-metal is not common stuff. Thus the final device as suggested appears to be good as a gravimeter where you wish to measure long range DC fluctuations in vertical gravitation -- where magnetic variations tend to average out average out compared to earth tides-- but becomes less attractive than using actual springs when you want to measure brief seismic disturbances. That doesn't mean this approach is hopeless, but that one must proceed with great caution and it won't be so easy as it may seem. It may actually be a nifty way to build a vertical component magnetometer if I knew some easy way to shield out the seismics. Suggestions? --Yours, Roger Baker At 10:32 AM 11/21/97 -0800, you wrote: >Norman -- > >No, those suggestions weren't made. I have thought about magnetic >repulsion some, but am trying to keep any magnetic materials off of the >moving parts of the system as much as possible; to reduce the sensitivity >to changing magnetic fields and moving ferromagnetic stuff in the area >(cars on the street, etc.). Do you have any suggestions for magnetic >repulsion that avoid these problems? > >What hydraulic ideas do you have? > >-- Karl > > >At 09:00 AM 11/21/97, you wrote: >> Karl >> I didn't monitor the entire conversation but did anyone happen to sugest >>magnetic repulsion or hydralics. > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: George Harris Subject: Re: Force of Lehman susp. wire Date: Fri, 21 Nov 1997 11:00:42 +0000 Robert L Barns wrote: > > Hi gang, > A question about the design of a Lehman seismometer has been in the back > of my mind for a long time and I finally got around to trying to answer it. > The question :Is the stiffness (or bending force) of the suspension wire > shortening the period of the Lehman? Obviously, if the wire was 1/4" in > diameter it would make the period very short. Because I have been experimenting with small Lehman units, I wondered about the same question. As a mechanical engineer, I have now convinced myself that the stiffness is not really important. This is due to the fact that the stiffness acts the same as the tilt of the vetical. That is, if the stiffness is increased, it is canceled out by a slight backward tilt of the axis. Very small units with flexure pivots can have long periods and high sensitivity if they are properly leveled. George Harris - Carpinteria, CA > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Re: Spring Material Date: Fri, 21 Nov 1997 15:54:02 >What hydraulic ideas do you have? > I am no engineer but was thinking that a piston on a column of fluid and a weight on top. The compression would act as a spring. The more compressable the fluid (i.e. gas ) the better or more spring in the system. Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: lahr@................. (Dr. John Lahr (USGS-GI Seismologist)) Subject: Homes Found Date: Fri, 21 Nov 1997 18:23:50 -0700 > From CIPAR@.......... Thu Nov 20 11:46 MST 1997 > From: CIPAR@.......... > Date: Thu, 20 Nov 1997 13:47:38 -0400 (EDT) > Subject: Re: seismometers need good home > To: lahr@................. > X-Vms-To: SMTP%"lahr@................." > Mime-Version: 1.0 > Content-Transfer-Encoding: 7BIT > > John: > > Thanks for responding to my message regarding the WWSSN seismometers. > > I've succeeded in finding a good home for them. The community expressed > a lot of interest, which is gratifying. > > Best Regards, > --John Cipar > AF Research Lab > Hi John, Glad to hear that you've found a spot for them. I'm sure the PSN folks would love to know where they are going. Thanks, JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Caveat and AGU abstract Date: Fri, 21 Nov 1997 20:26:04 -0700 Jane- Two last points. I have little or no responsibility for the PSN; it just spontaneously develops, and I just provide some kind of link between it and the USGS. The PSN can act as a liason between the general public and professional seismologists, doing a job the latter frequently feel they have no time for or interest in performing. I have included below a copy of the abstract of our AGU presentation on 12 Dec. Also I am forwarding a recent email to you written by Dr. John Lahr, USGS, to the PSN email listserver. John works with the PSN and has been a proponent of public involvement in seismology long before I got involved. Thank you for your interview. -Edward ************************************************************************ Public Seismic Network (PSN): a Model for Preparing People to use Real-time Information About Natural Hazards Edward Cranswick and Benjamin Gardner (U.S. Geological Survey, MS 966, Box 25046, Federal Center, Denver, CO 80225, USA; 303-273-8609; cranswick@......... Public Seismic Network (http://psn.quake.net/, psn-l@.............. When an earthquake occurs, unlike any other natural hazard, every individual in the population at risk is aware within seconds that a dangerous event has happened. Without the aid of any technology, the consciousness of everyone affected is almost instantaneously focused on the same subject. Instead of soliciting that information, authorities broadcast the redundant message that an earthquake has occurred. A program of monitoring natural hazards for the public requires public participation to effectively mitigate those hazards. The Public Seismic Network (PSN), rather than relegating them to the role of sitting ducks waiting to be devastated by the unexpected, enables people to become aware that earthquakes are part of normal, on-going Earth processes. The PSN is a rapidly growing international group of amateur seismologists, concentrated in California, who record earthquakes with their own digital seismographs and exchange waveform time series and communicate with each other via the Internet. At present, the PSN consists of about 50 seismograph stations, about 250 subscribers to its email list server, and about 10 websites. In urban areas of high seismic risk, a grassroots organization like the PSN -- equipped with low-cost, mass-produced, standardized strong-motion seismographs -- could vastly increase the spatial density of sampling ground motions. This organization would form a constituency of well-informed residents who not only know how to respond to catastrophic earthquakes but also support hazard mitigation programs in the community. Rather than just building faster ambulances to mitigate the impact of heart attacks, it is more effective to modify the public habits of exercise and diet. The PSN is a model for using technology to connect human awareness to, rather than shield it from, the environment. -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: AP interview about PSN Date: Fri, 21 Nov 1997 20:37:37 -0700 PSN members- Earlier this evening, Jane Allen, the science writer for Associated Press in Los Angeles, interviewed me over the phone about the Public Seismic Network and our upcoming American Geophysical Union (AGU) presentation. I believe she will be writing an article about this that will be published sometime during the week of the AGU meeting (8-12 Dec). -Edward -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: [Fwd: Re: Public Seismic Network meeting at USGS, Menlo Park] Date: Fri, 21 Nov 1997 20:41:32 -0700 -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". Ed- I have rescheduled your meeting for December 13, Saturday, Bldg. 8, Rm. 8111, all day. Kristine Edward Cranswick wrote: > Kristine- > I just talked to Larry Cochrane, PSN Redwood City, about the PSN > meeting to be held at USGS Menlo Park on Saturday 20 Dec, and he said > that because of conflicts with the Holidays, many PSN members would not > be able to attend that day. We are now trying to find out whether more > members would be able to attend on Saturday 13 Dec, in which case, we > would like to change the meeting at the USGS to that date. Please let > me know if that would be a problem. > -Edward > > Kristine Estrada wrote: > > > > Carl/Ed: > > > > I have alerted the Safety/Security office of this Saturday meeting in Building 8, > > Room 8111; the guard will be notified. I penciled the meeting in for "all day". > > Let me know the time your group plans to arrive and depart. > > Thanks, > > Kristine, x4140 > > > > Carl Mortensen wrote: > > > > > Ed - > > > > > > Because of the construction on building 3, building 8 has the > > > largest conference room on campus, so it has been transferred to the OPS > > > Division to administer. The person who takes the reservations is : > > > > > > name: Estrada, Kristine R > > > email: kestrada@........ (kestrada@............ > > > phone: 650-329-4140 > > > address: 345 Middlefield Road, MS 225 > > > : Menlo Park, CA 94025 > > > office_location: 01, Room 117 > > > department: OPS > > > > > > I've cc'd her on this message so that she can make the reservations > > > if it's available. > > > > > > Regards, > > > > > > Carl > > > > > > >Carl- > > > > Members of the Public Seismic Network (PSN) from the San Francisco Bay > > > >Area are planning to hold a meeting on Saturday, 20 December 1997, and > > > >John Lahr suggested that I contact you about the possibility of having > > > >that meeting in Building 8 of USGS, Menlo Park. Several years ago, in > > > >1993 I believe, Joe Sena and Jerry Eaton sponsored a similar PSN meeting > > > >that was held in Building 8 on a Saturday so that PSN members who worked > > > >during the week would be able to attend. > > > > We will be presenting a PSN poster at AGU on Friday, 12 Dec, and I will > > > >be in the Bay Area to work with the PSN the following week (14-20 dec) > > > >and to attend on the PSN meeting that Saturday. So, I will be available > > > >as the USGS representative to be responsible for the visitors. I > > > >anticipate that there would be 10-40 attendees. > > > > Please let me know if we may hold the PSN meeting at the USGS, Menlo > > > >Park, on Saturday, 20 Dec 1997. > > > >-Edward > > > > > > > >-- > > > >Edward Cranswick Tel: 303-273-8609 > > > >US Geological Survey, MS 966 Fax: 303-273-8600 > > > >PO Box 25046, Federal Center cranswick@........ > > > >Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". > > > > > > ____________________________________________________________________ > > > Carl Mortensen e-mail: cmortensen@.................. > > > US Geological Survey Phone: 650-329-4856 > > > 345 Middlefield Road, MS/977 Fax: 650-329-5163 > > > Menlo Park, CA 94025 > > -- > Edward Cranswick Tel: 303-273-8609 > US Geological Survey, MS 966 Fax: 303-273-8600 > PO Box 25046, Federal Center cranswick@........ > Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". From: barry lotz Subject: Re: Force of Lehman susp. wire Date: Fri, 21 Nov 1997 09:27:20 -0800 All Me Too! Barry James M Hannon wrote: > > I suspected that the bending wire would be a problem. So I designed my > Lehman with a knife edge pivot at the top. > > Jim Hannon > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: Which filter type is best? Date: Fri, 21 Nov 1997 09:44:09 -0800 Albert I obtained a book from Analog Devices called "Digital Signal Processing in VLSI" by Richard Higgins which I found great for me. It talks about digital filtering, windowing and FFTs in not to complicated math. I can send you some info on basic programming of digital filtering. Barry prewar wrote: > > Hi everyone, > No. 3 requires a nifty piece of fast software, which I am > prepared to do, BUT does anyone have the relevant maths > (simple if possible and not in C!... > ....I use basic + assembly language)? Have just bought a rather > expensive book on DSP but it doesn't give information required. > . > (It would seem that one has to take various proportions of > the previous data i/p's and sum them, but do not know > how these proportions relate to cut off frequency chosen > for filtering.) > > Plenty has been said in archives about filters, so I don't > wish to start it all up again. However, DSP does > seem to be the way ahead now, so I wonder if anyone > can suggest the best way forward, or even recommend > another book for me to buy? (As it's getting near to Xmas, > I might even persuade Father Xmas to buy it for me ) > > Regards, > > Albert Noble (England). > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: Spring Material Date: Fri, 21 Nov 1997 09:52:11 -0800 Norman & Karl I also was wondering about magnetic repulsion but what I had tried had fairly low periods since the magnet field probably decreases with the square of the distance. It would be great to have a mass suspended in a uniform magnetic field and measure it's movement with respect to ground. What I attempted ended up in unstable equilibrium (ball on a hill). I got discouraged and stopped with that idea. Barry Karl Cunningham wrote: > > Norman -- > > No, those suggestions weren't made. I have thought about magnetic > repulsion some, but am trying to keep any magnetic materials off of the > moving parts of the system as much as possible; to reduce the sensitivity > to changing magnetic fields and moving ferromagnetic stuff in the area > (cars on the street, etc.). Do you have any suggestions for magnetic > repulsion that avoid these problems? > > What hydraulic ideas do you have? > > -- Karl > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Local N. Cal PSN meeting. Date: Fri, 21 Nov 1997 20:46:51 -0700 Hi All, Well it looks like Saturday the 20 may not be a good time for a meeting. I only got three RSVP. My guess is its too close to the "holidays". If it will help we could move it one week earlier to Saturday the 13, except Ted Blank (of the three that RSVPed) can make it on that day. So if you can make it on either date please let me know ASAP, and, let me know what date is better. We can use a conference room at the USGS so that isn't a problem. Regards, Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Charlie Rond Subject: Re: Local N. Cal PSN meeting. Date: Sat, 22 Nov 1997 00:46:27 -0600 >Hi All, > >Well it looks like Saturday the 20 may not be a good time for a meeting. I >only got three RSVP. My guess is its too close to the "holidays". If it >will help we could move it one week earlier to Saturday the 13, except Ted >Blank (of the three that RSVPed) can make it on that day. > >So if you can make it on either date please let me know ASAP, and, let me >know what date is better. We can use a conference room at the USGS so that >isn't a problem. Wow, a conclave! Wish I could join you folks. Good luck with your meeting. Charlie Rond -\/\--Public Seismic Network-Memphis rond@................ (901) 360-0302 [ free BBS ] http://gandlf.ceri.memphis.edu/~rond http://gandlf.ceri.memphis.edu/~rond/psn _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: Force of Lehman susp. wire Date: Sat, 22 Nov 1997 08:43:16 +0000 Hi, Will enquire about 'spider wire' in fishing shops.... Wondering as its called wire, whether it is METAL or some sort of nylon etc? Over here.....it may be known under different name? Maybe your fish over there are BIGGER than ours, and require stronger lines...... . Regards, Albert Noble (England). Clark Wockner wrote: > You may want to inquire about a fishing line called spider wire. > It is for casting reels and the TV comercials show a guy pulling a tree > out with it. (grin) > Regards, Clark --Illinois > Mark Wison wrote: At first I used piano wire, then I used threaded cable from a plotter, After it broke, I tried spider wire... great stuff... man it's strong, does not stretch, very flexible, and is real easy to work with. Just don't use scissors to cut it.. It's been on mine for about 8 months now. Never had to adjust for stretch yet. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: wizard@......... (Rick Jerome) Subject: Re Digital Signal Processing Date: Sat, 22 Nov 1997 04:42:38 -0800 Barry Re Digital Signal Processing. Have you ever looked at a program called SCilab (free)? Also, I wonder if MATlab would work? I think Matlab has a toolbox that will do live processing of signals. I am not a math type, however, these program allows m anipulating of large data arrays. It has built in filtering and fft analysis. There is a student edition of Matlab available for $65-$80 from most technical booksellers. Scilab is free via ftp. ------------------------- Michael D N6EGQ Tuolumne, CA ------------------------- "The round, full moon was briefly seen from the window of a speeding car." _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Dewayne (n0ssy) & Linda (n0uqf) Hill" Subject: Force of Lehman susp. wire Date: Sat, 22 Nov 1997 06:27:35 -0700 Hi to all, I am new to this as many others are so bear with me. I am getting my hardware together to build my Lehman. In these postings I have seen piano wire, Spiderwire and various other materials suqqested for the boom suspension. I am a flyfisherman and tie my own flies. I have found at my local fly shop Kevlar thread that is used to tie flies. I am going to give that a try unless some of you already have and can give some negative feedback about the use of it. Regards, Dewayne Hill _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: Re Digital Signal Processing Date: Fri, 21 Nov 1997 21:01:43 -0800 Hi Rick No I wasn't aware of SCilab. I have a few programs that do filterng and FFTs but I was trying to include code for filtering in my data acquisition program. Currently I create the filter coefs. and include them in my program as a data file and let it run. I will have to look into SCilab. Thanks for the suggestion. Barry Rick Jerome wrote: > > Barry > Re Digital Signal Processing. Have you ever looked at a program called > SCilab (free)? Also, I wonder if MATlab would work? I think Matlab has > a toolbox that will do live processing of signals. I am not a math > type, however, these program allows manipulating of large data arrays. > It has built in filtering and fft analysis. There is a student edition > of Matlab available for $65-$80 from most technical booksellers. > Scilab is free via ftp. > ------------------------- > Michael D > N6EGQ > Tuolumne, CA > ------------------------- > "The round, full moon was briefly seen from > the window of a speeding car." > _____________________________________________________________________ > Public Seismic Network Mailing List (PSN-L) > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Mammoth M4.5 (FYI) Date: Sat, 22 Nov 1997 08:33:48 -0700 Here is a copy of the Seismo-Watch Earthquake Alert Bulletin that went out earlier this morning: *=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*= Seismo-Watch Alert Bulletin 97-308 Regional Location: MAMMOTH LAKES, CALIFORNIA Preliminary Magnitude: 4.5 ML (NCSN) Moment Magnitude: 4.5 Mw (UCB) Greenwich Mean Date: 97/11/22 Greenwich Mean Time: 12:06:56 Latitude: 37.64N Longitude: 118.93W Focal Depth: 8.4 km Analysis Quality: A An earthquake registering a preliminary magnitude of ML 4.5 (Mw 4.5) occurred at 12:06 UTC (4:06 a.m. PST), November 22, at Mammoth Lakes, California. The quake was centered about 3 miles east-southeast Mammoth Lakes near the Highway 395/203 interchange. The Moment magnitude was provided by University of California, Berkeley. The focal depth was at 8.4 km (5.2 miles) beneath the surface. Preliminary reports indicate the quake shook the region quite sharply, waking many residence and resort visitors from sleep. A vigorous sequence has followed the quake and during the first three hours, rates have reached 37-40 M1+ quakes/hr and has included five events in the M3 range - the largest a M3.3 at 4:26 a.m. The M4.5 quake was the largest in the intense microearthquake swarm that has surged on and off in the Long Valley volcanic caldera since it began the first week of July. *=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*= -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Mammoth M4.5 (FYI) Date: Sat, 22 Nov 1997 09:37:32 -0800 (PST) Hello All: I just checked the USGS "Long Valley Caldera Web Page for an update on the so-called "current condition." Here is what they stated: The CURRENT CONDITION is GREEN (moderate unrest posing no Immediate Risk). Last updated at 5:55 AM (PST) on 22 November 1997. See Response Plan for information on conditions, activity levels, and the Long Valley caldera response plan. Caldera activity: Earthquake activity within the caldera picked up again with a M=4.5 event at 4:07 AM (PST) on the 22nd located 0.5 miles south of the Highway 203-395 junction (3 miles ESE of Mammoth Lakes). As of 5:40 AM, this sequence has included many smaller earthquakes, three of which have magnitudes greater than M=3: a M=3.2 event at 4:12, a M=3.6 event at 4:20, and a M=3.4 event at 4:27 all located in the vicinity of the highway juction. Now, if you ask me I would be very concerned over the increased seismic activity in the vicinity of Mammoth Lakes! Isn't it getting to the point where it poses a direct danger to anyone who happens to be in the area of the ski slopes when and if another large earthquake does occur? It seems to me that the USGS is patronizing the business interests of the Mammoth Lakes tourist industry by not going to a higher level alert status. I'm sure after the 4.5 earthquakes of this morning that the current level of seismic events has increased to the magic "thousand events" mentioned in my previous posting. Why else wouldn't this last event at least cause them to go to the "Yellow" status level? BTW I'm located in the seismic corridor between Fontana and Mammoth Lakes and expect to see some more activity there soon! Frank Condon mail to: frankcnd@.......... >Here is a copy of the Seismo-Watch Earthquake Alert Bulletin that went >out earlier this morning: > >*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*= > > >Seismo-Watch Alert Bulletin 97-308 > >Regional Location: MAMMOTH LAKES, CALIFORNIA > >Preliminary Magnitude: 4.5 ML (NCSN) > >Moment Magnitude: 4.5 Mw (UCB) > > Greenwich Mean Date: 97/11/22 > Greenwich Mean Time: 12:06:56 > Latitude: 37.64N > Longitude: 118.93W > Focal Depth: 8.4 km > Analysis Quality: A > > >An earthquake registering a preliminary magnitude of ML 4.5 (Mw 4.5) >occurred at 12:06 UTC (4:06 a.m. PST), November 22, at Mammoth Lakes, >California. The quake was centered about 3 miles east-southeast Mammoth >Lakes near the Highway 395/203 interchange. The Moment magnitude was >provided by University of California, Berkeley. The focal depth was at >8.4 km (5.2 miles) beneath the surface. Preliminary reports indicate the >quake shook the region quite sharply, waking many residence and resort >visitors from sleep. A vigorous sequence has followed the quake and >during the first three hours, rates have reached 37-40 M1+ quakes/hr and >has included five events in the M3 range - the largest a M3.3 at 4:26 >a.m. The M4.5 quake was the largest in the intense microearthquake >swarm that has surged on and off in the Long Valley volcanic caldera >since it began the first week of July. > >*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*= > >-- >---/---- >Charles P. Watson, Consulting Geologist >Advanced Geologic Exploration >Seismo-Watch / Earthquake Information Services >Voice: 702-852-0992 / Fax: 702-852-3226 >Office Location: 39.43N 119.71W >mailto:watson@................ >http://www.seismo-watch.com > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roger Baker Subject: Re: Force of Lehman susp. wire Date: Sat, 22 Nov 1997 11:59:42 -0600 DeWayne, I think you will soon find that any organic polymer is far too stretchy to work as well as steel wire or some kind of metal strut, since one of the critical requirements of a Lehman is to have the wire keep the horizontal beam and mass from drooping ANY, if possible, so that you can adjust the period and then have this critical adjustment remain stable. --Yours, Roger Baker At 06:27 AM 11/22/97 -0700, you wrote: >Hi to all, > > I am new to this as many others are so bear with me. >I am getting my hardware together to build my Lehman. In these postings >I have seen piano wire, Spiderwire and various other materials suqqested >for the boom suspension. I am a flyfisherman and tie my own flies. I have >found at my local fly shop Kevlar thread that is used to tie flies. I am >going to give that a try unless some of you already have and can give some >negative feedback about the use of it. > >Regards, Dewayne Hill > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Mammoth M4.5 (FYI) Date: Sat, 22 Nov 1997 10:04:20 -0700 Those are good comments, Frank, and I would not want to be in the USGS shoe's during this one. They seem to damned if they voice concern or damned if they are conservative. Very tricky proposition. Yet, I side with the USGS on this one. Clearly, there is no volcanic threat at this time. Go to this page to see their thinking on the subject: http://quake.wr.usgs.gov/VOLCANOES/LongValley/unrest.html Moreover, look at the depths of the activity. The M4.5 was at 8.4 km beneath the surface with the balance of the swarm at 5-8 km. It has a long way to go before it reaches the surface. As I have been since the 1996-1997 quiecence and continuing deformation of the resurgence dome, I am concerned about a larger quake, say, M6+. It would not unreasonable given the statistical number of events already recorded. I think the USGS feels the same way but what are they to do, wave the flag as they did in the 1980's. No. The consurvative approach is more resonable. As scientific evidence outlined in the Alert Status Plan comes in to play, then they should voice a conern. Unfortunately, the press and the public do not take kindly to feelings that do not play out. -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ken Navarre Subject: Wow... Date: Sat, 22 Nov 1997 10:06:47 -0800 (PST) Quite a while ago Larry, Steve Hammond, Joe Sena and I were talking about what the PSN's role should be following a "notable" earthquake. We discussed that perhaps we (PSN) could field a team that could respond into the area and set up a public information station that could be used to let folks in the affected area know whats going on. The ususal media just covers the same old, same old. You know, "aftershocks continue blah blah." "Damage is reported in..." The people in the shelters have always comented about the lack of information about what was taking place under the ground and how it could affect them - right then. The public Safety folks are innundated with information that help them develop their response plans but the PIO people can't be everywhere and rarely do they present technical information that so many of the victims are interested in. That's an area where PSN members could fill a need. Setting up "field stations" at some of the schools that serve as shelters or at a Red Cross information/aid station. Places where people could come and see what was going on and get some answers to their questions. Obviously we should develop some guidelines for our activites but I think that we certainly could provide a service that is sorely needed. At my worksite I have set up a telemetry receiving station in the lobby of our aministration building. The city administrators were quite suprized at how much background activity goes on that they never hear about. It has forced them to be aware that we're going to be hit with an event that will seriously imact their community. They all "know" that someday the "big one" will hit but most remain in comfortable denial that it will probably come during someone else's administration. Kind'a like tax day. April 15th is ALWAYS a long way off - until it surprizes us by being just a few days away and we haven't even looked at the tax forms... :( If Mammoth continues to stay active perhaps we western PSN folks should plan for a "field trip" to test our ability to respond into an area and set up a monitoring/display station. See if we really could keep a field station running for a week or so and if we could rotate some of our volunteers though so we could keep it operating in "field conditions". Or maybe not... Maybe another topic for discussion at the December meeting... Wow. Mammoth is REALLY bouncing today! One event right after another. Getting some good waveforms here in the San Jose area today! Everybody take care. Stay dry... Ken _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Marnie Gannon Subject: Re: Mammoth M4.5 (FYI) Date: Sat, 22 Nov 1997 10:53:39 -0700 Frank Condon wrote: > > Hello All: > > I just checked the USGS "Long Valley Caldera Web Page for an update on the > so-called "current condition." Here is what they stated: > > The CURRENT CONDITION is GREEN (moderate unrest posing no Immediate Risk). > Last updated at 5:55 AM (PST) on 22 November 1997. See Response Plan for > information on conditions, activity levels, and the Long Valley caldera > response plan. Hello everyone.. I would imagine the usgs will stick with its plan re: 5.0. Wouldn't avalanche be the greatest threat right now? Anyone know the snow level there? Recent storms? Most interesting of all..the last 3.0 shows a depth of 0.0km. The depths have gotten wildly anomolous, 29.0km all the way to 0.0km, and there are several others below 1.km. Just received a report of a 4.4 in Big Pine, albeit with a poor location. Marnie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Marnie Gannon Subject: new Mammoth 4.6 Date: Sat, 22 Nov 1997 11:18:20 -0700 Hey guys..correction: the usgs list shows the "Big Pine" quake to be at Mammoth.. with an "A" location: 97/11/22 17:19:41 37.64N 118.92W 7.1 1.1MD B* 3 mi ESE of Mammoth Lakes, CA 97/11/22 17:20:35 37.64N 118.94W 7.3 4.6MD A* 2 mi ESE of Mammoth Lakes, CA 97/11/22 17:24:02 37.63N 118.92W 0.7 3.2Ml C* 3 mi ESE of Mammoth Lakes, CA 97/11/22 17:24:41 37.63N 118.93W 7.2 2.9Ml B* 2 mi ESE of Mammoth Lakes, CA 97/11/22 17:27:36 37.64N 118.94W 14.1 3.1MD B* 2 mi ESE of Mammoth Lakes, CA 97/11/22 17:30:03 37.57N 119.01W 2.0 2.2MD D* 6 mi SSW of Mammoth Lakes, CA 97/11/22 17:30:57 37.63N 118.90W 8.3 2.5MD A* 4 mi ESE of Mammoth Lakes, CA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: new Mammoth 4.6 Date: Sat, 22 Nov 1997 10:39:43 -0700 And I had a nice afternoon planned.... -- ---/---- cpw _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Wow...Eeeeks! Date: Sat, 22 Nov 1997 11:04:29 -0700 Here is the frequency of the Mammoth activity since 7 pm last night: 7 pm 7 quakes/hour 8 pm 7 quakes/hour 9 pm 19 quakes/hour 10 pm 22 quakes/hour 11 pm 14 quakes/hour 12 am 10 quakes/hour 1 am 4 quakes/hour 2 am 9 quakes/hour 3 am 3 quakes/hour 4 am 37 quakes/hour - M4.5 and 4 M3’s 5 am 36 quakes/hour 6 am 40 quakes/hour 7 am 49 quakes/hour - M3 8 am 41 quakes/hour 9 am 62 quakes/hour - M4.6 and 6 M3’s < Subject: Re: Wow... Date: Sat, 22 Nov 1997 13:30:15 -0700 Ken- The Earth at Mammoth is sending some interesting signals, and the PSN (Charlie Watson, Marnie Gannon, Phil Giannini, Karl Cunningham, you, ....) is responding with some interesting email. -Edward Ken Navarre wrote: > > Quite a while ago Larry, Steve Hammond, Joe Sena and I were talking about > what the PSN's role should be following a "notable" earthquake. We > discussed that perhaps we (PSN) could field a team that could respond into > the area and set up a public information station that could be used to let > folks in the affected area know whats going on. The ususal media just > covers the same old, same old. You know, "aftershocks continue blah > blah." "Damage is reported in..." The people in the shelters have > always comented about the lack of information about what was taking > place under the ground and how it could affect them - right then. > > The public Safety folks are innundated with information that help them > develop their response plans but the PIO people can't be everywhere and > rarely do they present technical information that so many of the victims > are interested in. > > That's an area where PSN members could fill a need. Setting up > "field stations" at some of the schools that serve as shelters or at a > Red Cross information/aid station. Places where people could come and > see what was going on and get some answers to their questions. Obviously > we should develop some guidelines for our activites but I think that we > certainly could provide a service that is sorely needed. > > At my worksite I have set up a telemetry receiving station in the lobby > of our aministration building. The city administrators were quite > suprized at how much background activity goes on that they never hear > about. It has forced them to be aware that we're going to be hit with an > event that will seriously imact their community. They all "know" that > someday the "big one" will hit but most remain in comfortable denial that > it will probably come during someone else's administration. Kind'a like tax > day. April 15th is ALWAYS a long way off - until it surprizes us by > being just a few days away and we haven't even looked at the tax forms... :( > > If Mammoth continues to stay active perhaps we western PSN folks should > plan for a "field trip" to test our ability to respond into an area and > set up a monitoring/display station. See if we really could keep a field > station running for a week or so and if we could rotate some of our > volunteers though so we could keep it operating in "field conditions". > > Or maybe not... Maybe another topic for discussion at the December > meeting... > > Wow. Mammoth is REALLY bouncing today! One event right after another. > Getting some good waveforms here in the San Jose area today! > > Everybody take care. Stay dry... > > Ken > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Do Three Four Plus Earthquakes = 5.0? Date: Sat, 22 Nov 1997 12:39:23 -0800 (PST) Hello All: I just finished scanning the latest information on the epicenters of the current sequence located at Mammoth Lakes. I know I've been a little worried that the USGS has not upgraded their "moderate unrest" status to at least the "Yellow" level. But, I ask you all, "when will the ampunt of earthquakes seen in the Caldera area be enough to cause an alert status change by the USGS?" Enough is enough!, let's error on the side of safety! It is getting close to the holiday weekend and soon many visitors to the area will have not a single inkling of the ongoing threat to their lives while hotdogging down those slopes if and when the next earthquake occurs. Come on USGS! Let's get real about this situation. Give people a chance to decide for themselves if the risk is worth the pleasure afforded by going there! Frank Condon mail to:frankcnd@.......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: Do Three Four Plus Earthquakes = 5.0? Date: Sat, 22 Nov 1997 14:11:36 -0700 Frank- You should also send your email to hill@................... -Edward Frank Condon wrote: > > Hello All: > I just finished scanning the latest information on the epicenters of the > current sequence located at Mammoth Lakes. I know I've been a little worried > that the USGS has not upgraded their "moderate unrest" status to at least > the "Yellow" level. But, I ask you all, "when will the ampunt of earthquakes > seen in the Caldera area be enough to cause an alert status change by the > USGS?" Enough is enough!, let's error on the side of safety! It is getting > close to the holiday weekend and soon many visitors to the area will have > not a single inkling of the ongoing threat to their lives while hotdogging > down those slopes if and when the next earthquake occurs. Come on USGS! > Let's get real about this situation. Give people a chance to decide for > themselves if the risk is worth the pleasure afforded by going there! > > Frank Condon > > mail to:frankcnd@.......... > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Do Three Four Plus Earthquakes = 5.0? Date: Sat, 22 Nov 1997 13:32:02 -0800 (PST) Hello Edward: I took your advice and sent a slightly modified version of my posting to the USGS. Also, I sent out a Cc: to the PSN. I will let you know if I get a response from them. Thanks, Frank Condon "Located in the seismic corridor somewhere between Fontana and Mammoth Lakes!" mail to:frankcnd@.......... >Frank- > You should also send your email to hill@................... >-Edward > >Frank Condon wrote: >> >> Hello All: >> I just finished scanning the latest information on the epicenters of the >> current sequence located at Mammoth Lakes. I know I've been a little worried >> that the USGS has not upgraded their "moderate unrest" status to at least >> the "Yellow" level. But, I ask you all, "when will the ampunt of earthquakes >> seen in the Caldera area be enough to cause an alert status change by the >> USGS?" Enough is enough!, let's error on the side of safety! It is getting >> close to the holiday weekend and soon many visitors to the area will have >> not a single inkling of the ongoing threat to their lives while hotdogging >> down those slopes if and when the next earthquake occurs. Come on USGS! >> Let's get real about this situation. Give people a chance to decide for >> themselves if the risk is worth the pleasure afforded by going there! >> >> Frank Condon >> >> mail to:frankcnd@.......... >> >> _____________________________________________________________________ >> >> Public Seismic Network Mailing List (PSN-L) >> >> To leave this list email listserver@............. with the body of the >> message: leave PSN-L > >-- >Edward Cranswick Tel: 303-273-8609 >US Geological Survey, MS 966 Fax: 303-273-8600 >PO Box 25046, Federal Center cranswick@........ >Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Do Three Four Plus Earthquakes = 5.0? Date: Sat, 22 Nov 1997 13:37:02 -0700 It takes 10 M4.0 quakes to equel a Richter magnitude change and 33 of them to make a factor change in energy release. That would also correlate to 1,000 M3's warrenting a jump to M5, or 10,000 M2's, or 100,000 M1's. At last count, there have only been a few dozen M3's throughtout the life of this swarm, and this morning's pair of M4's are the first in the nearly five month-long sequence. While a few hundred M1+ events/day is spectular, this is not uncommon with active volcanic systems and does not meet the INTENSE UNREST qualifications outline in the Status Alert scale. The Staus Alert scale does need some modifications. You will notice is goes from MODERATE UNREST to INTENSE UNREST in one jump. There is no doubt this was done intentially so that media would not create undo panic during low to mid level activity. An for this current sequence, it does seem prudent to stay at the MODERATE UNREST until further data becomes available. I have made some suggestions to the USGS and raised the issue at yesterday's Nevada Earthquake Safety Council, who by the way, are concerned about the increased level of activity earthquake activity observed throughout the western Basin and Range during the past three weeks. A Status Alert change for MODERATELY STRONG and STRONG UNREST is needed to gain the appreciation of the public for the potential hazard. -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com Frank Condon wrote: > > Hello All: > I just finished scanning the latest information on the epicenters of the > current sequence located at Mammoth Lakes. I know I've been a little worried > that the USGS has not upgraded their "moderate unrest" status to at least > the "Yellow" level. But, I ask you all, "when will the ampunt of earthquakes > seen in the Caldera area be enough to cause an alert status change by the > USGS?" Enough is enough!, let's error on the side of safety! It is getting > close to the holiday weekend and soon many visitors to the area will have > not a single inkling of the ongoing threat to their lives while hotdogging > down those slopes if and when the next earthquake occurs. Come on USGS! > Let's get real about this situation. Give people a chance to decide for > themselves if the risk is worth the pleasure afforded by going there! > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Do Three Four Plus Earthquakes = 5.0? Date: Sat, 22 Nov 1997 13:57:31 -0800 (PST) Hello Charles: Thanks for the clarification about magnitude vs. quantity. I always wondered about that. How far do you think the USGS is from making an alert level status change in regard to the current activity? Why do they need the 5.0 before the status can change? Isn't the alert status more or less geared towards an erruption alert and not indicative of a earthquake alert? I'm sure that an erruption is a remote possibility compared to say the occurance of a magnitude larger earthquake in the Mammoth Lakes region. Thanks, Frank Condon "Located in the seismic corridor somewhere between Fontana and Mammoth Lakes" mail to:frankcnd@.......... >It takes 10 M4.0 quakes to equel a Richter magnitude change and 33 of >them to make a factor change in energy release. That would also >correlate to 1,000 M3's warrenting a jump to M5, or 10,000 M2's, or >100,000 M1's. At last count, there have only been a few dozen M3's >throughtout the life of this swarm, and this morning's pair of M4's are >the first in the nearly five month-long sequence. While a few hundred >M1+ events/day is spectular, this is not uncommon with active volcanic >systems and does not meet the INTENSE UNREST qualifications outline in >the Status Alert scale. > >The Staus Alert scale does need some modifications. You will notice is >goes from MODERATE UNREST to INTENSE UNREST in one jump. There is no >doubt this was done intentially so that media would not create undo >panic during low to mid level activity. An for this current sequence, it >does seem prudent to stay at the MODERATE UNREST until further data >becomes available. I have made some suggestions to the USGS and raised >the issue at yesterday's Nevada Earthquake Safety Council, who by the >way, are concerned about the increased level of activity earthquake >activity observed throughout the western Basin and Range during the past >three weeks. > >A Status Alert change for MODERATELY STRONG and STRONG UNREST is needed >to gain the appreciation of the public for the potential hazard. > >-- >---/---- >Charles P. Watson, Consulting Geologist >Advanced Geologic Exploration >Seismo-Watch / Earthquake Information Services >Voice: 702-852-0992 / Fax: 702-852-3226 >Office Location: 39.43N 119.71W >mailto:watson@................ >http://www.seismo-watch.com > > >Frank Condon wrote: >> >> Hello All: >> I just finished scanning the latest information on the epicenters of the >> current sequence located at Mammoth Lakes. I know I've been a little worried >> that the USGS has not upgraded their "moderate unrest" status to at least >> the "Yellow" level. But, I ask you all, "when will the ampunt of earthquakes >> seen in the Caldera area be enough to cause an alert status change by the >> USGS?" Enough is enough!, let's error on the side of safety! It is getting >> close to the holiday weekend and soon many visitors to the area will have >> not a single inkling of the ongoing threat to their lives while hotdogging >> down those slopes if and when the next earthquake occurs. Come on USGS! >> Let's get real about this situation. Give people a chance to decide for >> themselves if the risk is worth the pleasure afforded by going there! >> > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Do Three Four Plus Earthquakes = 5.0? Date: Sat, 22 Nov 1997 14:06:02 -0700 Holy Cow! Did you see the record at 11 am? Another pair of M4.7! and a dozen M3's. You my get you wish for an Alert Status change! Thar be some good data now! -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Do Three Four Plus Earthquakes = 5.0? Date: Sat, 22 Nov 1997 14:43:18 -0800 (PST) Hello Charles: Yes, I couldn't miss it! I'm checking in regularly during this near crisis! If Mammoth were to get another larger event, I expect to see some increase in activity between Bishop and Barstow due to sympathetic earthquakes. Watch out Ridgecrest! Frank Condon "Located in the seismic corridor somewhere between Fontana and Mammoth Lakes" mail to:frankcnd@.......... >Holy Cow! Did you see the record at 11 am? > >Another pair of M4.7! and a dozen M3's. > >You my get you wish for an Alert Status change! Thar be some good data >now! > >-- >---/---- >Charles P. Watson, Consulting Geologist >Advanced Geologic Exploration >Seismo-Watch / Earthquake Information Services >Voice: 702-852-0992 / Fax: 702-852-3226 >Office Location: 39.43N 119.71W >mailto:watson@................ >http://www.seismo-watch.com > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Marnie Gannon Subject: Current LV status Date: Sat, 22 Nov 1997 15:47:05 -0700 Here's the latest report on the caldera..I have no doubt they are monitoring like mad! Since most lists are several hours behind, including UNR and usgs CA/NEV..I found two which are more timely: http://quake.wr.usgs.gov/QUAKES/CURRENT/norcal.list (-20 min) http://www.cnss.org/cnss.cat.html (-40 min) The CURRENT CONDITION is GREEN (moderate unrest posing no Immediate Risk). Last updated at 1:30 PM (PST) on 22 November 1997. See Response Plan for information on conditions, activity levels, and the Long Valley caldera response plan. Caldera activity: The earthquake sequence that began this morning (Nov 22) with a M=4.5 earthquake at 4:07 AM continues through 1:30 PM in the afternoon. This sequence has included two additional earthquakes of M > 4 (a M=4.8 event at 9:21 AM and a M=4.7 at 10:11 AM), some 20 earthquakes of M > 3 all accompanied by several hundred smaller events. These earthquakes are located 2-3 miles ESE of Mammoth Lakes (about 0.5 miles south of the 203-395 highway junction) at depths of 6 to 8 km (4 to 5 miles). This activity is still within the bounds of condition GREEN (no immediate risk). We will track and continiously evaluate the activity around the clock over the the next several days. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: No Change of Alert Status Yet Date: Sat, 22 Nov 1997 14:55:34 -0800 (PST) Hello All: Will you look at what the USGS is saying about the latest events in the Mammoth Lakes area: The CURRENT CONDITION is GREEN (moderate unrest posing no Immediate Risk). Last updated at 1:30 PM (PST) on 22 November 1997. See Response Plan for information on conditions, activity levels, and the Long Valley caldera response plan. Caldera activity: The earthquake sequence that began this morning (Nov 22) with a M=4.5 earthquake at 4:07 AM continues through 1:30 PM in the afternoon. This sequence has included two additional earthquakes of M > 4 (a M=4.8 event at 9:21 AM and a M=4.7 at 10:11 AM), some 20 earthquakes of M > 3 all accompanied by several hundred smaller events. These earthquakes are located 2-3 miles ESE of Mammoth Lakes (about 0.5 miles south of the 203-395 highway junction) at depths of 6 to 8 km (4 to 5 miles). This activity is still within the bounds of condition GREEN (no immediate risk). We will track and continiously evaluate the activity around the clock over the the next several days. I'm not sure that they are taking this too seriously from the looks of it. Frank Condon "Located in the seismic corridor somewhere between Fontana and Mammoth Lakes"" Mail to:frankcnd@.......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: No Change of Alert Status Yet Date: Sat, 22 Nov 1997 15:03:22 -0700 No M3's since 11 am. 70 quakes/hour @ 1900 UTC is the tops thus far! Gee, it relaxed back to 65 q/hr at 2000 UTC -- ---/---- cpw _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Robert L. Hancock" Subject: Mammouth Lakes Activity Date: Sat, 22 Nov 1997 17:39:18 -0500 I have been following the increased activity at Mammouth Lakes over the past several months. The past few days have really been interesting. I have also been following the interest in setting up some type of information outlet for the public - press - etc. In my current job for a small federal agency, I am responsible for the press contacts I have when I investigate aviation accidents. I can tell you from several years in this job that the press is ONLY looking for quick simple answers. I am not certain that those answers are avaiable for the Mammouth Lakes events at this time. I have seen well meaning, technically competent personnel shreaded by the press in their attempts to explain something. The press wants a quick answer for the 6:00 PM news, anything that cannot be put into a 30 sec or less sound bite will not sell. A five minute disertation will never float. I wonder if the current story at Mammouth Lakes can be accurately told in a 30 second sound bite. While I share everyone's concern about the current level and where will it lead, I can tell you from personnel experience that incomplete information can do far more harm than good. Equally bad is sensationalism. The press loves it, the people panic, the news sells advertising time, but who is served, certainly not the public, and the people who live in the Mammouth Lakes region. Dealing with the press can be tricky at best. It is not an area for personnel that are technically competent, but untrained in how the press operates. Just some thoughts from another person who has been watching all this on the sidelines. Bob Hancock _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Re: Force of Lehman susp. wire Date: Sat, 22 Nov 1997 20:26:17 -0500 Jim, = Good idea about the pivot for the wire even though my calc. seems to sh= ow that wire stiffness (under the conditions stated) has no effect in limiti= ng the period. The pivot scheme (or variations) should put to rest the sear= ch for exotic materials such as carbon fiber and 'spider wire'. (BTW, I wou= ld like to hear what 'spider wire' is:is it metal, plastic or what?) Perhaps a simplification of your knife edge pivot would be to use 'crossed rings'. By this I mean to put a ring on the end of the wire and= a ring fixed (at right angles) on the support. Since this contact would be= a rolling contact, it's effect on boom motion should be zero. I can imagin= e some alignment problem with the knife edge which would not occur with the= rings.This ring arrangement was prompted by the message from Al Allworth.= = Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Re: Force of Lehman susp. wire Date: Sat, 22 Nov 1997 20:26:20 -0500 Karl, = Am I missing something (besides a brain)? I agree that both the force from the wire and the restoring force due to gravity are linear with deflection but I don't see how they can cancel. = I think that the use of flexures in commercial seismometers is to make them portable, not that they have no effect on the period. I'm curious about your calculation of the required width of the pivot point on the end of the boom. I am convinced that the long moment arm an= d the large mass at the end of the boom makes the motion almost completely insensitive to friction at the pivot. A frictionless pivot for the end of the boom is the "Zollner' suspensio= n which is described in Aki & Richards, "Quantitative Seismology", vol. 1, 1980, p 484. I made a mock-up of this and it works but I don't think it= is necessary. I use a steel disk about 1.5" dia. The edge is very dull having a radiu= s of something like 0.01". This presses against the flat surface of a bras= s bar with the disk roughly vertical. This is very easy to adjust. Since this is a rolling contact, I can't imagine that lubrication would help because the motion has no sliding component and the pressures are enormou= s which will squeeze out any lubricant. A small steel ball should work as well as the disk. The effect of pivot friction should be apparent in the recording of the= output signal. If the boom freezes momentarily, the output would show fl= at spots down to the noise level of the amplifier. I have looked for this a= nd have not seen it. I think that the normal seismic noise may be enough dither the system and overcome possible friction. = Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Dewayne (n0ssy) & Linda (n0uqf) Hill" Subject: Date: Sat, 22 Nov 1997 19:04:09 -0700 Here is the newbe again. Can some on e tell me what the Q factor is or refer my to a web page that explains it? Regards, Dewayne _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: Do Three Four Plus Earthquakes = 5.0? Date: Sat, 22 Nov 1997 19:17:19 -0700 (MST) On Sat, 22 Nov 1997, Frank Condon wrote: > Hello All: > I just finished scanning the latest information on the epicenters of the > current sequence located at Mammoth Lakes. I know I've been a little worried > that the USGS has not upgraded their "moderate unrest" status to at least > the "Yellow" level. But, I ask you all, "when will the ampunt of earthquakes > seen in the Caldera area be enough to cause an alert status change by the > USGS?" Enough is enough!, let's error on the side of safety! It is getting > close to the holiday weekend and soon many visitors to the area will have > not a single inkling of the ongoing threat to their lives while hotdogging > down those slopes if and when the next earthquake occurs. Come on USGS! > Let's get real about this situation. Give people a chance to decide for > themselves if the risk is worth the pleasure afforded by going there! > Frank Condon Frank, Don't forget about the political side of the issue! When it really comes down to it, the politicians will decide, not sound science... ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Tobin Fricke" Subject: Re: Do Three Four Plus Earthquakes = 5.0? Date: Sat, 22 Nov 1997 18:25:48 -0800 -----Original Message----- From: John Hernlund To: PSN-L Mailing List Date: Saturday, November 22, 1997 6:28 PM Subject: Re: Do Three Four Plus Earthquakes = 5.0? >Frank, > Don't forget about the political side of the issue! When it really >comes down to it, the politicians will decide, not sound science... Especially in Mammoth. Tourism is the main industry of Mammoth, so the volcanic and seismic activity of the area is kept quiet. Take, for example, Mammoth's Casa Diablo geothermal powerplant. I thought it was pretty cool, but unless you're looking for it, you won't realize it exists. Or the "Mammoth Scenic Loop," otherwise known as the Mammoth emergency escape route. Tobin _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Do Three Four Plus Earthquakes = 5.0? Date: Sat, 22 Nov 1997 19:23:17 -0800 (PST) Hello John: Sad but true it is that the politics and business of earthquakes supercedes the balance of risk! That the USGS would lean towards being the silence in a vacuum on this issue. I guess it is the Governor of California who makes the final call. And I suspect that he is well versed in the commercial disadvantages of an earthquake alert for Mammoth Lakes, especially right before what is essentially one of the peak weeks of the holiday season for skiers hitting the slopes. Frank Condon "Located in the seismic corridor somewhere between Fontana and Mammoth Lakes" mail to:frankcnd@.......... >Frank, > Don't forget about the political side of the issue! When it really >comes down to it, the politicians will decide, not sound science... > > > >****************************************************************************** > > John Hernlund > E-mail: hernlund@....... > WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ > >****************************************************************************** > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Robert L. Thomasson" <102073.3346@..............> Subject: Re: Do Three Four Plus Earthquakes = 5.0? Date: Sat, 22 Nov 1997 23:57:14 -0500 > Don't forget about the political side of the issue! When it really >comes down to it, the politicians will decide, not sound science... <> Gentlemen, I have to offer a counterpoint, and I also suggest that we, myself included, should try and stay with the purpose of this forum, whic= h is exchanging technical information. There is really no way to keep the seismic and potential volcanic activi= ty quiet in this day and age of the media. The quakes are daily news here i= n Reno and all the skiers and tourists know about it, and some of them choose to go to Mammoth anyway. = Geothermal power plants are, by definition, located in environmentally sensitive areas and the plants and piping are all painted a color that blends in with the local scenery. This is generally a BLM or USFS requirement. = The emergency escape route was paved - I think it was mainly an old loggi= ng road - after the major quake of 1982. It was a decision made by local politicians and a courageous and responsible one, since there was opposition to the idea and the expense. The "scenic route" designation= is probably not as forthright as "escape route", but at least they built= the road. The USGS has been dealing with the possibility of volcanic activity or a major earthquake in Mammoth for a long time. They're in a tough situation, since there is no 'sound science' for predicting earthquakes = or volcanic eruptions and unnecessary escalations of the alert level will result in the loss of credibility. They are much better at what they'r= e doing than we're giving them credit for. The local business community doesn't want unnecessary alerts, but they do want realistic information, since they all live there themselves and don't want to die. = Regards, Bob Thomasson _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: Do Three Four Plus Earthquakes = 5.0? Date: Sat, 22 Nov 1997 23:15:17 -0700 Robert- I am impressed by and I welcome your calm tone and fair-mindedness in discussing the issues related to the current seismic unrest in Mammoth. I would like to think, however, that "the purpose of this forum" is more than just "exchanging technical information"; your posting is proof off that. Ultimately, we are concerned about our connection with the Earth, and the technical aspect of seismology is a way of extending our perception of that relationship. Seismographs permit many of us to sense the state of the Earth and share that awareness with each other even when we are too far away to feel the ground shaking, the Earth moving, ourselves. The first earthquakes I chased in California, my first use of portable autonomous digital seismographs, my first feeling of a large earthquake occurred during our investigation of the 25 May 1980 Mammoth Lakes sequence that started with three magnitude 6 earthquakes on the Sunday one week after Mount St Helens erupted and two months after I started working for the USGS. It was the end of the ski season, and all the skiers left Mammoth that Sunday night and were replaced by an influx of seismologists on Monday morning, including myself. On Tuesday morning, a magnitude 6.4 event occurred, the largest in the sequence -- just as I jumped off a pickup truck in the parking lot of the ski chalet where we had driven to pickup some of our colleagues who were staying there -- and I saw ripples propagate up the asphalt driveway (I also saw a bunch of seismologists come running out of the chalet, after the silence when it stopped shaking, in the their underwear), and seventeen years later I have not yet experienced a larger earthquake or stronger ground motions. However, this afternoon I visited Meredith Lamb, who recently connected with the PSN, at his home in Denver, and saw his chart record of today that was full of surface-wave trains from Mammoth. He has been running seismographs on and off for more than 30 years in Denver, and he said he has not seen that kind of activity before. So being with him and Ben Gardner in the crawl space under his house that serves as his seismograph vault re-connected me to Mammoth and the start of my career with the USGS. Meredith has three components of Sprengnether 20-second seismometers installed and ready to go, and I am looking forward to when he starts recording them all digitally. -Edward Robert L. Thomasson wrote: > > > Don't forget about the political side of the issue! When it really > >comes down to it, the politicians will decide, not sound science... > > < volcanic and seismic activity of the area is kept quiet. Take, for > example, > Mammoth's Casa Diablo geothermal powerplant. I thought it was pretty cool, > but unless you're looking for it, you won't realize it exists. Or the > "Mammoth Scenic Loop," otherwise known as the Mammoth emergency escape > route.>> > > Gentlemen, I have to offer a counterpoint, and I also suggest that we, > myself included, should try and stay with the purpose of this forum, which > is exchanging technical information. > > There is really no way to keep the seismic and potential volcanic activity > quiet in this day and age of the media. The quakes are daily news here in > Reno and all the skiers and tourists know about it, and some of them > choose to go to Mammoth anyway. > > Geothermal power plants are, by definition, located in environmentally > sensitive areas and the plants and piping are all painted a color that > blends in with the local scenery. This is generally a BLM or USFS > requirement. > The emergency escape route was paved - I think it was mainly an old logging > road - after the major quake of 1982. It was a decision made by local > politicians and a courageous and responsible one, since there was > opposition to the idea and the expense. The "scenic route" designation > is probably not as forthright as "escape route", but at least they built > the road. > > The USGS has been dealing with the possibility of volcanic activity or a > major earthquake in Mammoth for a long time. They're in a tough > situation, since there is no 'sound science' for predicting earthquakes or > volcanic eruptions and unnecessary escalations of the alert level will > result in the loss of credibility. They are much better at what they're > doing than we're giving them credit for. The local business community > doesn't want unnecessary alerts, but they do want realistic information, > since they all live there themselves and don't want to die. > > Regards, Bob Thomasson > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Tobin Fricke" Subject: Hi Everyone Date: Sat, 22 Nov 1997 22:30:06 -0800 I thought maybe I'd introduce myself since I've been listening here for over a year.. I may have done this before but I'm not sure. I'm a senior this year at Mission Viejo High School in Orange County in Southern California. I love Physics and Chemistry and Mathematics and the sciences in general. Currently I keep bees with a friend of mine. I am interested in seismology too. How difficult would it be for me and a group of friends to construct a seismograph or two, so that we, too, could watch these events that everyone is discussing roll in? I'd really like it to be digital.. Dedicating a computer to the cause is no problem at all. I've always thought that a good seismograph would be something too expensive to purchase and something too complex to construct, but I'd like to be proven wrong. How can I get started? Tobin Fricke fricke@.................... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Re: Mammouth Lakes Activity Date: Sat, 22 Nov 1997 21:19:15 >In my current job for a small federal agency, I am responsible for the >press contacts I have when I investigate aviation accidents. Sounds like a FSDO inspector. What office? Norm RIU AFSS Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Re: Hi Everyone Date: Sun, 23 Nov 1997 08:22:21 How difficult would it be for me and a group of friends to construct a >seismograph or two, so that we, too, could watch these events that everyone >is discussing roll in? I'd really like it to be digital.. Dedicating a >computer to the cause is no problem at all. > Tobin I am just finishing a lehman and if you are at davis and need to look at one you are welcome to look here. I am in Shingle Springs east of Sacramento. Also I think Larry is in redwood city. Check out the web site. Lots of good information there. That is where I got all mine from. Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Minimum sampling rate. Date: Sun, 23 Nov 1997 08:24:08 What is the minimum sampling rate for the a/d converter. I have been using the RS multi meter and it is only 1 sec. Don't think it is going to hack it as it see's me but nothing else. Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Listing of seismic rates at ML Date: Sun, 23 Nov 1997 10:20:55 -0700 Here is the complete list of seismic rates for the November 22, 1997, Mammoth Lakes seismic swarm: 4 am 37 q/hour - M4.5 (4:06 am) and 4 M3šs 5 am 36 q/hour 6 am 40 q/hour 7 am 49 q/hour - M3.0 8 am 41 q/hour 9 am 62 q/hour - M4.6 (9:20 am) and 6 M3šs 10 am 66 q/hour - M4.8 (10:11 am) and 9 M3šs 11 am 70 q/hour - M3.6 12 pm 65 q/hour 1 pm 55 q/hour 2 pm 48 q/hour - M3.1 3 pm 36 q/hour - M3.0 4 pm 47 q/hour 5 pm 36 q/hour - M3.2 6 pm 42 q/hour - M3.7 7 pm 31 q/hour 8 pm 46 q/hour - M3.0 9 pm 36 q/hour 10 pm 20 q/hour - M3.8 11 pm 21 q/hour 12 am 14 q/hour 1 am 17 q/hour 2 am 10 q/hour 3 am 11 q/hour 4 am 13 q/hour 5 am 17 q/hour 6 am 24 q/hour 7 am 19 q/hour Clearly the M4's did not provide enough relief to cause the overall swarm to subside. It well be interesting to track the activity during the next few days/weeks. -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: Do Three Four Plus Earthquakes = 5.0? Date: Sun, 23 Nov 1997 15:35:23 -0700 (MST) I agree that criticism is probably unwarranted concerning the Mammoth Lakes activity. One thing is for sure though: I don't care how much Hill is paid to do his job but I don't think I would want to be in his shoes. We have seen volcanoes erupt with much less warning than LVC is experiencing right now, but at the same time this kind of increased activity is usually nothing. So Hill is in a tough spot. If he ups the alert, which leads to an evacuation and then nothing happens he will be criticized. If he doesn't and the caldera eruption vaporizes every living thing in the area he will also be criticized. The probability of avoiding criticism is very small! Either way though, I have met Hill, and heard him tell the story of LVC, and in the end I think he knows what to do better than anyone else on this planet. ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: Spring Material Date: Sun, 23 Nov 1997 15:58:36 -0700 (MST) On Fri, 21 Nov 1997, Karl Cunningham wrote: > No, those suggestions weren't made. I have thought about magnetic > repulsion some, but am trying to keep any magnetic materials off of the > moving parts of the system as much as possible; to reduce the sensitivity > to changing magnetic fields and moving ferromagnetic stuff in the area > (cars on the street, etc.). Do you have any suggestions for magnetic > repulsion that avoid these problems? I think the main problem with magnetic repulsion is the non-linear restoring force on the mass. You could perform some kind of mathematical filter on it to convert it out of this effect but the data on the upswing of the pendulum would be more dense than on the downswing. This may not be a problem though... I think most magnetic repulsion would follow a general equation for restoring force of: F = -k*x^n (where n is around 2) This would create an accelerating system something like this: A(t) = g - k*x^n (where A(t) is the acceleration of the ground) Subsequent integration would yield a more complicated result than would be found for linear restoring force in references like Richter's Elementary seismology... But it can be done, and working backwards through collected data could yield the correct linear ground velocity... ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: what is Q? Date: Sun, 23 Nov 1997 17:28:29 -0700 Dewayne & Linda- Q is a measure of the elastic efficiency of a medium that propagates seismic waves. The seismic attenuation, 1/Q, is to the Earth what damping is to a seismometer. More precisely, from QUANTITATIVE SEISMOLOGY: THEORY AND METHODS by Aki& Richards: "If a volume of material is cycled in stress at a frequency 'w', then a dimensionless measure of the internal friction (or the anaelasticity) is given by 1 dE ---- = - ------ Q(w) 2*pi*E where 'E' is the peak strain energy stored in the volume and '-dE' is the energy lost in each cycle because of imperfections in the elasticity of the material." High Q's mean that seismic waves propagate with little anelastic loss, low Q's mean that seismic waves, particularly the high-frequency, i.e., short-wavelength, waves are significantly attenuated as they propagate. -Edward Dewayne (n0ssy) & Linda (n0uqf) Hill wrote: > > Here is the newbe again. > > Can some on e tell me what the Q factor is or refer my to a web page that > explains it? > > Regards, Dewayne > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: Minimum sampling rate. Date: Sun, 23 Nov 1997 06:20:14 -0800 Norman If you are measuring velocity(measuring acceleration is higher), most local events are under 10hz,so oversampling at 30hz would work. If you are recording teleseismic events sampling at 8hz would work. Don't forget to filter frequencies above 1/2 the sampling frequency. I hope that helps. Barry Norman Davis WB6SHI wrote: > > What is the minimum sampling rate for the a/d converter. I have been using > the RS multi meter and it is only 1 sec. Don't think it is going to hack it > as it see's me but nothing else. > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Caruso Subject: Re: Minimum sampling rate. Date: Sun, 23 Nov 1997 21:24:40 -0500 (EST) I am going to set my sample rate at 17hz, the same as human muscle tetanus. I figure it is so for a good reason! Since earth surface is at 8 hz. than 2x8+1=17 ought to cover good ground! I found that dataq outputs in codas. Is that compatible w/winquake file interpretations? On Sun, 23 Nov 1997, barry lotz wrote: > Norman > If you are measuring velocity(measuring acceleration is higher), > most local events are under 10hz,so oversampling at 30hz would work. If > you are recording teleseismic events sampling at 8hz would work. Don't > forget to filter frequencies above 1/2 the sampling frequency. I hope > that helps. > Barry > Norman Davis WB6SHI wrote: > > > > What is the minimum sampling rate for the a/d converter. I have been using > > the RS multi meter and it is only 1 sec. Don't think it is going to hack it > > as it see's me but nothing else. > > > > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L STEPHEN CARUSO CET KB8UGH "Coincidence is a shortsighted mental delusion" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Tobin Fricke" Subject: Re: Hi Everyone Date: Sun, 23 Nov 1997 18:42:44 -0800 > I am just finishing a lehman and if you are at davis and need to look at >one you are welcome to look here. I am in Shingle Springs east of >Sacramento. Also I think Larry is in redwood city. Check out the web site. >Lots of good information there. That is where I got all mine from. I just looked at the SciAm article that's on the PSN website.. Looks doable! How much did it cost to build? Actually, I'm in SoCal, about an eight hour drive from Davis. )-: Tobin Fricke (KE6WHF) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: Do Three Four Plus Earthquakes = 5.0? Date: Sun, 23 Nov 1997 20:56:53 -0600 Edward Cranswick wrote: > > Robert- > I am impressed by and I welcome your calm tone and fair-mindedness in > discussing the issues related to the current seismic unrest in Mammoth. > I would like to think, however, that "the purpose of this forum" is more > than just "exchanging technical information"; your posting is proof off > that. Ultimately, we are concerned about our connection with the Earth, > and the technical aspect of seismology is a way of extending our > perception of that relationship. Seismographs permit many of us to > sense the state of the Earth and share that awareness with each other > even when we are too far away to feel the ground shaking, the Earth > moving, ourselves. The first earthquakes I chased in California, my > first use of portable autonomous digital seismographs, my first feeling > of a large earthquake occurred during our investigation of the 25 May > 1980 Mammoth Lakes sequence that started with three magnitude 6 > earthquakes on the Sunday one week after Mount St Helens erupted and two > months after I started working for the USGS. It was the end of the ski > season, and all the skiers left Mammoth that Sunday night and were > replaced by an influx of seismologists on Monday morning, including > myself. On Tuesday morning, a magnitude 6.4 event occurred, the largest > in the sequence -- just as I jumped off a pickup truck in the parking > lot of the ski chalet where we had driven to pickup some of our > colleagues who were staying there -- and I saw ripples propagate up the > asphalt driveway (I also saw a bunch of seismologists come running out > of the chalet, after the silence when it stopped shaking, in the their > underwear), and seventeen years later I have not yet experienced a > larger earthquake or stronger ground motions. However, this afternoon I > visited Meredith Lamb, who recently connected with the PSN, at his home > in Denver, and saw his chart record of today that was full of > surface-wave trains from Mammoth. He has been running seismographs on > and off for more than 30 years in Denver, and he said he has not seen > that kind of activity before. So being with him and Ben Gardner in the > crawl space under his house that serves as his seismograph vault > re-connected me to Mammoth and the start of my career with the USGS. > Meredith has three components of Sprengnether 20-second seismometers > installed and ready to go, and I am looking forward to when he starts > recording them all digitally. > -Edward > This discussion reminds me of Mt St Helens. I had the opportunity of visiting Mt St Helens a year or so after it blew and before the public was allowed back. It was an awesome experience to be standing in the middle of the destruction and then feel the whump of a pressure wave, turn around and see a 20000 ft column of dirt in the air. We spent 2 weeks camped out there studying how the plant life that was regrowing. I had several campfire discussions with a scientist from the university who was involved with the monitoring before the blast. Most interesting was the relationships with the press. There seems to be this idea that you can easily get people to panic in these situations. They had the opposite problem. Could not convince people to stay away. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Robert L. Thomasson" <102073.3346@..............> Subject: Re: Do Three Four Plus Earthquakes = 5.0? Date: Sun, 23 Nov 1997 22:44:18 -0500 Edward, "the purpose of this forum" is more > than just "exchanging technical information" I agree, and what I think I probably meant is let's try to be accurate i= f we're going to discuss politics. I was two years off on the date of the big Mammoth quake. Regards, Bob Thomasson _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: Hi Everyone Date: Sun, 23 Nov 1997 06:35:56 -0800 Tobin You can find many inexpensive 12 bit A/D plug in boards for PCs(probably from $50 up).Nuts & Volts or Electronics Now are a few pubs. which show boards. Larrys hardware and software is also available. EMON by Ted Blank is what I am using on two sensors. It comes with a list of supported boards. I have been using a 16 chan. 12 bit board from Acqutek for years. I think it cost me around $110. EMON supports it also. I hope this helps. Barry Tobin Fricke wrote: > > I thought maybe I'd introduce myself since I've been listening here for over > a year.. I may have done this before but I'm not sure. I'm a senior this > year at Mission Viejo High School in Orange County in Southern California. > I love Physics and Chemistry and Mathematics and the sciences in general. > Currently I keep bees with a friend of mine. I am interested in seismology > too. How difficult would it be for me and a group of friends to construct a > seismograph or two, so that we, too, could watch these events that everyone > is discussing roll in? I'd really like it to be digital.. Dedicating a > computer to the cause is no problem at all. I've always thought that a good > seismograph would be something too expensive to purchase and something too > complex to construct, but I'd like to be proven wrong. How can I get > started? > > Tobin Fricke > fricke@.................... > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roger Baker Subject: Re: Spring Material Date: Sun, 23 Nov 1997 23:17:14 -0600 Karl and John et al, While it is true that magnetic fields are quite non-linear, force feedback can take care of this problem quite nicely by keeping the mass effectively motionless. The other big problem, which I have experienced, is that the earth field noise gets mixed up with the seismic signal. I think I may try to build a model with powerful rare earth magnets supporting a lead mass on a razor blade pivot so that the earth field becomes much less important by comparison than is the case with my current ceramic magnet version. One of the major virtues of magnetic suspension is very high Q. One possible disadvantage is that the metallic conductivity of such magnets may reduce the inherent Q of the support system by inductive damping, possibly reducing long period sensitivity. This change might have the effect of making the whole instrument even smaller as a bonus, however. --Yours, Roger Baker At 03:58 PM 11/23/97 -0700, you wrote: >On Fri, 21 Nov 1997, Karl Cunningham wrote: >> No, those suggestions weren't made. I have thought about magnetic >> repulsion some, but am trying to keep any magnetic materials off of the >> moving parts of the system as much as possible; to reduce the sensitivity >> to changing magnetic fields and moving ferromagnetic stuff in the area >> (cars on the street, etc.). Do you have any suggestions for magnetic >> repulsion that avoid these problems? > > I think the main problem with magnetic repulsion is the non-linear >restoring force on the mass...John _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: Force of Lehman susp. wire Date: Sun, 23 Nov 1997 21:59:00 -0800 Bob -- Sorry, I forgot to mention a very important part. That to have the one force cancel the other, the leveling of the Lehman must be adjusted so that the upper pivot is behind the lower one. Without the force of the piano wire, this would result in a period >infinity, which I think in mathematical terms would be a negative period. But the addition of the force from the piano wire brings it back to positive, and in the case I was talking about, close to infinite. Following is a description of the pivot size calculations. If you want more detail about any of it, please ask. Also, if anyone sees any mistakes or oversights, I'd appreciate hearing about it. The calculation of pivot point size went something like this: Givent the angle of the suspension wire and a five-pound weight, the force on the pivot is about 6.25 pounds. Imagining that if what appears to be a pivot point is really a very small squared-off end, there will be a rest position of the boom where the whole flat end of the square pivot is touching the support plate. When movement occurs, there will be a certain force required to move the mass, which will involve rocking the "squared-off" pivot end to one side. In the process, the boom and mass will be moved ever so slightly away from the mast, and due to the Lehman geometry, it will be lifted against gravity in the process. This is in addition to the lifting of the mass against gravity due to its being suspended as a pendulum. At motion frequencies near or below the natural frequency of the pendulum, the effect of gravity pushing the mass back toward its rest position is the factor that limits the sensitivity of a Lehman-type instrument. Adding to gravity is this force due to the imperfection of the pivot point. I reasoned that if the force due to the pivot is very much more than the restoring force of gravity, I'm not getting the full potential of the instrument. The calculation of pivot width involved equating the restoring force on the mass due to gravity with the sideways force on the mass imparted by the squared-off end of the pivot for the deflection due to a small earthquake. A few background things: 1. The earth movement for a M2.0 at 100km (given some other assumptions) will be 36nm (Dr. John Lahr, post to this list 11/29/96). 2. The length of a simple pendulum with a period of 20 seconds is about 100 meters. 3. I used my force balance as the example geometry, which uses a 5-lb weight, a 15-inch boom, the piano wire has an angle of about 38.65 degrees from horizontal, and its free period is about 20 seconds. First, calculate the restoring force on the mass due to gravity for a 20-second pendulum, a five-pound weight, and a displacement of 36nm: F = x/l * Fo Where x is the displacement, l is the length of the equivalent simple pendulum, and Fo is the force on the mass due to gravity (its weight). So 36nm/99m * 5lb = 1.818E-9 lb, or 8.25E-7 grams. (These new calculators that handle units of measure are wonderful things.) Next, calculate the width of the squared-off pivot that would cause 8.25E-7 grams of force. In my case, the force on the pivot is about 6.25lb. w = 2 * 8.25E-7 grams / 6.25 lb * 15 inches = 2.2E-10 meters, or about .22 nanometers. As a side note, a .22nm square with 6.25 lb of force on it undergoes a compression pressure of 8.33E16 psi. So even if the point could be sharpened that sharp, it wouldn't stay that way under pressure. Obviously, this isn't what's really going on. If the pivot starts out very sharp, when placed in service it will plasticly deform (along with the peice it is pushing against) until its end is large enough to support the force, then hopefully deform elastically and just bend as the boom swings. But for larger excursions of the boom, it may again plastically deform, or microscopically slip, or even grind off little pieces of metal that may get in the way. So my conclusion was that for small earth displacements near the natural period of the Lehman, the pivot probably is something that may limit sensitivity. I haven't seen any freezing up either. I think that may be due to the pivot deforming elastically, which shouldn't be very lossy. As I described before, I had quite a bit of hysteresis on the long-period output (bandwidth .5sec to 100 sec). It may have been due to slippage of the pivot, or something else. But it sure got a lot better when I put a drop of oil on the pivot. All in all, I think flexures are the way to go. They undoubtedly have their own problems (microscopic oil-canning is one I can think of), and I'm not sure about operating them in compression. Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ted Blank Subject: Re: Hi Everyone Date: Sun, 23 Nov 1997 22:29:35 -0800 (PST) Tobin, don't forget to build a combination amplifier/lowpass filter if you want to record anything but 60 Hz noise from your fluorescent bulbs. :-) Larry's PSN web page has the schematics. Best regards, Ted _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: Force of Lehman susp. wire Date: Mon, 24 Nov 1997 05:45:14 -0600 Karl Cunningham wrote: > > Bob -- >SNIP > > Obviously, this isn't what's really going on. If the pivot starts out very > sharp, when placed in service it will plasticly deform (along with the > peice it is pushing against) until its end is large enough to support the > force, then hopefully deform elastically and just bend as the boom swings. > But for larger excursions of the boom, it may again plastically deform, or > microscopically slip, or even grind off little pieces of metal that may get > in the way. > > So my conclusion was that for small earth displacements near the natural > period of the Lehman, the pivot probably is something that may limit > sensitivity. > > > All in all, I think flexures are the way to go. They undoubtedly have > their own problems (microscopic oil-canning is one I can think of), and I'm > not sure about operating them in compression. > > Karl Cunningham > La Mesa, CA. > PSN Station #40 > karlc@....... > Karl, A very interesting and useful calculation. A commercial seismograph that I saw once had carbide pivot knives and agate supports. They claimed long life with this pivot method. It it possible to arrange the flexures so that both are in tension. I worried about all kinds of secondary modes of vibration with this arrangment. So I didn't persue the flexures. Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: Force of Lehman susp. wire Date: Mon, 24 Nov 1997 07:24:25 -0600 Albert, Surrounded as you are by the Atlantic you certanly have access to bigger fish than a lot of us who are landlocked. :) There is also a product called tiger tail. It is used for bead stringing. It consists of seven strands of fine stainless steel wire covered with plastic. Jim Hannon prewar@.............. on 11/22/97 02:43:16 AM Please respond to psn-l@............. To: psn-l@............. cc: (bcc: James M Hannon/CedarRapids/Collins/Rockwell) Subject: Re: Force of Lehman susp. wire Hi, Will enquire about 'spider wire' in fishing shops.... Wondering as its called wire, whether it is METAL or some sort of nylon etc? Over here.....it may be known under different name? Maybe your fish over there are BIGGER than ours, and require stronger lines...... . Regards, Albert Noble (England). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Re: Force of Lehman susp. wire Date: Mon, 24 Nov 1997 11:19:37 -0500 Roger, = I concur with your feelings about non-metallic fibers. I studied classical guitar for a few years and observed that a new set of nylon strings took 2 or 3 months to get to the point where only occasional tuni= ng was required. Steel strings take days to settle down but they are a lot faster than nylon. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: Force of Lehman susp. wire Date: Mon, 24 Nov 1997 14:03:37 -0800 Karl Cunningham wrote: .... > All in all, I think flexures are the way to go. They undoubtedly have > their own problems (microscopic oil-canning is one I can think of), and I'm > not sure about operating them in compression. I would think flexures would be the way too, but I'm confused by the last statement. It should always be possible to put the flexure in tension by reversing the position of the stationary and arm pivots. What I can't figure out at the moment is: How would one put a flexure pivot in tension, but not in shear where the pivots would be coaxial and essentially vertical as they are in a conventional Lehman? An interesting thought would be to extend the previous thought from Robert Barns of using disks. He said the disk was vertical, which would imply that the rolling contact was the .01 inch radius of the rolled edge. If one were to use slices of disks horizontally, then the entire motion would be based on rolling motion, which should be very low friction. Large ball bearings ( the disks) captured on the arm in pyramidal holes (3 point kinematic restraints) and rolling against tool steel flats, for instance. Now the problem would be how to keep it from sliding apart. What I keep coming back to is the old Rolamite band bearings. They are extremely low friction, do not require lubrication, and are definitely controlled in position. They could be made from drill rod or Thompson rod bearing stock. The hard part would be the alignment. They are are roller bearings in terms of the geometry, and would need very accurate coaxial alignment. This could be accomplished by overlapping the rods and tying them together with a third, to make the alignment. I'll try to make it clear with a ascii drawing -- if you want better, I can sketch it, scan it, and email it to anybody who is interested. I don't want to burn up the PSN mail list bandwidth +--------------------\ | \ | | \ | |===Fixed to support \ | \ | | | \ | | | <==Tied together \ | | | with hose clamps \ | \ Fixed=======| | \ to support | | \ +-----------------------------+Boom Weight + + +--Three pieces of drill rod or equiv. Charles R. Patton Editor, Geo-Monitor work 714-932-7476 home 909-698-9657 email: patton@......... Geo-Monitor homepage: http://iinet.com/users/patton _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: George Harris Subject: Re: Flexure pivots Date: Mon, 24 Nov 1997 22:40:25 +0000 Charles R. Patton wrote: > > Karl Cunningham wrote: > ... > > All in all, I think flexures are the way to go. > I would think flexures would be the way too, but I'm confused by the > last statement. It should always be possible to put the flexure in > tension by reversing the position of the stationary and arm pivots. > What I can't figure out at the moment is: How would one put a flexure > pivot in tension, but not in shear where the pivots would be coaxial and > essentially vertical as they are in a conventional Lehman? An Flexure pivots can be used in pure tension if the geometry is correct. The secret is to have the flexure element attachment points tilted in such a way that their extensions would meet at the center of gravity of the mass system. As an example, assume that the pivots are on the left, and the mass on a beam to the right. The lower pivot could be horizontal, that is the attachment points of the flexure are on a horizontal line and aligned with the beam. The fixed lower support is to the right of the attachment to the beam. That is, the beam must pass around the support and have its attachment to the left of the support. The mass will then cause this flexure to be in tension. The upper flexure should be tilted so that its extension would pass through the center of mass. The edges of the flexure strips support should be vertical, but the attachment points of the flexure should point toward the mass. I have used .002 mylar in this configuration with a 9 inch beam weighing only a few ounces. By proper alignment, the natural period can be made 10 seconds or more. The strips are about 1/4 inch wide and clamped with square washers with only 1/8 inch of the flexure exposed. As has been pointed out, the stiffness of the flexure is not critical, since it can be eliminated by slight backward tilting of the line through the flexures. The only trouble is if the beam is allowed to move a long distance. There seems to be in inflection point where the beam will then swing to the limit due to the backward tilt. George Harris - Carpinteria, CA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: Flexure pivots Date: Mon, 24 Nov 1997 23:56:32 -0800 At 10:40 PM 11/24/97 +0000, George Harris wrote: > There seems to be >in inflection point where the beam will then swing to the limit due >to the backward tilt. The inflection point you speak of could be due to a changing "hinge point" as the boom swings. (By hinge point I mean the center of the arc described by the boom.) Perhaps the hinge point is moving toward or away from the mast. A possible way around this is to use criss-crossed flexures: MAST //////////// ----------- \ / \ / TWO CROSSED \ / FLEXURES X / \ / \ /-----\ | | | B | | O | | O | | M | The "hinge point" will not necessarily be where the flexures cross, but I think it won't change as the boom swings. Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: Earthquake Bulletin Date: Tue, 25 Nov 1997 11:45:41 -0700 Bob- I will be coming back from the San Francisco Bay Area on Sunday 21 Dec the day after the PSN meeting in Menlo Park, and I will be in town for the next week at least (unless there is an earthquake somewhere, and we chase it; I spent Xmas 1988 in Armenia, USSR). I would like to show you around the USGS in Golden one of those days before Xmas. I am leaving for San Francisco on 5 Dec, so please let me know your plans before then, though I will probably be in touch with my email while I am in California. I don't know what is going on with NEIC or John Lahr's arrival time calculator, but he has just transferred here from Alaska to work with NEIC, and I have forwarded your email to him. See you next month. -Edward Bob Lewis wrote: > > Hi Ed...Do you know what's happened to the NEIC Bulletins? The last update was > Friday, Nov. 21; nothing posted since then. Dr. Lahr's arrival time calculator > isn't working either... > > We've finally made our plans to visit my wife's brother in Denver for > Christmas. We will be in Denver from Dec. 18th through the 25th. Let me know > what your plans are, and if you're going to be in town during that time; I'll > make plans to come up one day at your convenience. > > --------------------------------------------------------------- > > Name: ATTRIBS.BND > Part 1.2 Type: unspecified type (application/octet-stream) > Encoding: X-UUENCODE -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Minimum sampling rate. Date: Tue, 25 Nov 1997 14:00:21 -0500 Norman, The Nyquist criterion (which is almost certainly true) sez that the sampling rate should be at least 2 times the highest freq. to be measured= =2E Local events have a lot of information in the higher freqs., say up to = 10 Hz, so sampling at at least 20/sec would be required. Teleseismic events have little energy above 0.1 Hz so a sampling rate o= f 1 Hz would be more than enough. I use 1 sample/sec. and get very good recordings. Of course, a low pass filter before the A/D is required and= it should allow very little energy to pass which is above 1/2 the samplin= g freq. I use a filter with a knee at 0.08Hz. I also have a Radio Shack DMM with the RD-232 interface and find it ver= y handy for a variety of jobs (e.g., battery discharge curves) and mine wil= l get > 2 samps/sec. The main problem with it for seis. work is the dynami= c range. The largest number it will record is 2,000. So if you set your amp. gain to get say 20 counts with the seismic background, the largest 'quake you can see without clipping would have a signal/noise ratio of on= ly 100. I have gotten a fair number which exceed that. Larry's board has a= 16 bit A/D which has a max. count of 65,000 which is almost always adequate. Another major problem with the RS DMM is that is not compatible with SD= R. SDR is great for many reasons not the least of which is that the record can be displayed and analyzed by WINQUAKE. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredithlamb@........ (meredith c lamb) Subject: 1. semi-converting a Sprengnether? 2. LVDT coils; can a Date: Tue, 25 Nov 1997 14:39:15 -0700 Hi Group, 1. Distant future wise, I'am considering adding on to my Sprengnethers a LVDT and using the normal damping coil as the force feed back. The other remaining coil could still be used for normal velocity output, which it is anyway. Am not to technically orientated; but it seems to be an interesting conversion thought. The distance between the possible LVDT and feedback coil may be 6-8 inches. I haven't read of any specific conversion or add on, in previous email. Basically I am asking for opinion or feedback? 2. Could 3 normal relay coils, (excluding jumble wound), be used in a LVDT? I think I'am getting the idea that they are precison layered and that maybe the only major factor involved? Would ferrite be better than annealed steel/iron? Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: N.Cal meeting set for Dec 20. Date: Tue, 25 Nov 1997 17:32:28 -0700 Hi Everyone, I got a few more RSVPs and all of them said the either day was fine. Since more people can come on Dec 20th then the 13th, we will have it on the 20th. The time will be 11:00am and the location is building 8, Room 8111, at the Menlo Park USGS campus. I will be placing a map on my web site in a few days. If you plain to attend, and have not RSVPed yet, please do so so we can get an idea of how many people will be attending. See you there.... -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Re: Minimum sampling rate. Date: Tue, 25 Nov 1997 16:48:50 > The main problem with it for seis. work is the dynamic >range. The largest number it will record is 2,000. So if you set your >amp. gain to get say 20 counts with the seismic background, the largest >'quake you can see without clipping would have a signal/noise ratio of only >100. I have gotten a fair number which exceed that. Larry's board has a >16 bit A/D which has a max. count of 65,000 which is almost always >adequate. I do plan to get going with sdr but not right away. Do I need to have a DC amp for the DVM to give a decent registration. I have been trying the 2oo mv range and do get a reading but don't see any quakes. Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: Force of Lehman susp. wire Date: Wed, 26 Nov 1997 08:42:34 -0800 More thoughts -- George Harris' post to this list on 11/24 made me think about another possible problem in period adjustment of long-period Lehman seismometers made with suspension wires. When the boom moves just barely to the side, the piano wire will naturally bend to accommodate it. This bending really occurs over the entire unsupported length of the wire, with an apex of the bend at some point near the top support. As the boom moves further from its rest position, the force in the suspension wire pulls more to the side and the apex point of the bend will move in the direction of the top support. The result of this is as if the whole instrument were being rocked backward. This will have the effect of lengthening the period and, if the period is already fairly long, may push the period past infinity for anything but the smallest excursions of the boom. Strategies to improve this might include shortening the portion of the suspension wire that is allowed to bend, limiting the travel of the boom to as small an amount as possible. Another possibility is to use thicker wire. Thicker wire will increase the restoring force and need to be compensated for by leveling adjustment, but it may reduce the change in apex position. Also, I think that criss-crossed flexures may work better. Another problem is that the longer the period, the more sensitive the system is to the mechanical stability of the base and mast. I haven't done any calculations on this recently, but I beleive a Lehman adjusted for 30 seconds presents quite a challenge in this regard. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: gchantler@....... (Gary Chantler) Subject: quake?? Date: Wed, 26 Nov 1997 11:35:58 -0800 Hi all, picked up a signal (must be aliens) this morning Nov 26/97 at 07:50 loval time (15:50 utc) but I have not seen any posts on it yet. Has any one else received anything (or should I attempt to make contact). Waves are a few seconds in period and lasted for about 12-15 min or so - I'm guessing as I haven't really taken a close look. I'm in Pullman, S.E. Washington State Home of the Rose Bowl Bound Cougars! *********************************************************** ***************************************** Gary R. Chantler Instructional Tech. II Geology 101 (509) 335-5353 Webster Rm 922 gchantler@....... *#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#* _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Marnie Gannon Subject: Re: quake?? Date: Wed, 26 Nov 1997 12:48:19 -0700 Gary Chantler wrote: > > Hi all, > picked up a signal (must be aliens) this morning Nov 26/97 at > 07:50 loval time (15:50 utc) but I have not seen any posts on it yet. Gary, The time's a little off but this could be it: 97/11/26 15:38:53 29.62N 113.95W 10.0 5.1Ms A GULF OF CALIFORNIA Marnie Gannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: peaches@............ (Donna Whitaker) Subject: Re: quake?? Date: Wed, 26 Nov 1997 09:54:17 -1000 (HST) Hi all and Gary. It was prob the Baha event. This is what the IDC has. Mag usually is low. a 1997/11/26 15:38:57.6 29.54N 114.12W 27 14.1 mb 4.3 Baja California, Mexico Tony >Hi all, > picked up a signal (must be aliens) this morning Nov 26/97 at >07:50 loval time (15:50 utc) but I have not seen any posts on it yet. Has >any one else received anything (or should I attempt to make contact). > >Waves are a few seconds in period and lasted for about 12-15 min or so - >I'm guessing as I haven't really taken a close look. > >I'm in Pullman, S.E. Washington State >Home of the Rose Bowl Bound Cougars! > >*********************************************************** >***************************************** >Gary R. Chantler >Instructional Tech. II >Geology 101 >(509) 335-5353 Webster Rm 922 >gchantler@....... >*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#* > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Walt Williams" Subject: What does it all mean? Date: Wed, 26 Nov 1997 16:55:18 +0000 Hello All, I came across interesting abstract titled: "Artificial neural networks for seismic data interpretation" at: http://www.sti.nasa.gov/cgi-bin/waisgate?WAISdocID=8510327954+9+ 0+0&WAISaction=retrieve&WAISlogFile=/home3/wais/waislog Best Regards, Walt Williams, 97.11.26 dfheli@.............. Woodland Hills, (LA suburb), California USA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Station almost ready Date: Wed, 26 Nov 1997 19:37:35 -0700 (MST) Hello Everyone. I have almost completed working on the horizontal seismometer I talked about a week ago or so. I am giving it a test run over this long weekend and hopefully an event will come to pass in that time. I am definitely dealing with a noise problem at 10 Hz and around 18 Hz. Probably building system noise, so I'll see what I can do about that. The noise is much lower than what I had to deal with from the vertical benioff's location compared to the amplitude of a small disturbance on the concrete slab. I have not put in a damping resistor either, because I would like to see what it does without one installed first... If I manage to get an event I'll certainly send it to the events list. Thanks again everyone for all your input! ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: What does it all mean? Date: Wed, 26 Nov 1997 09:58:07 -0800 Walt I couldn't seem to go to the location you show from Netscape. Any thoughts. Barry Walt Williams wrote: > > Hello All, > > I came across interesting abstract titled: > "Artificial neural networks for seismic data interpretation" > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert Avakian Subject: Re: Minimum sampling rate. Date: Wed, 26 Nov 1997 23:42:03 -0800 A different idea on the entire signal recording problem was used by a geophysical contractor a number of years ago and was called sign bit recording. They wanted to add channles of recorders so they did away with the bulk of the A/D process and recorded just the sign of the amplitude of the geophone signal (1 bit per sample) albeit at a higher, "over sampled" rate. Integrating the data recovered the waveform. The results were accurate and, on the whole, removed concern over recording satbility, amplifier performance, electronic noise, and accuray in A/D. I wonder if this would hold any advantages to our work? Unfortunately I for get the company's name but I am sure one could hunt up some atricles in old issues of Geophysica, the journal of the SEG. Bob Avakian Robert L Barns wrote: > > Norman, > The Nyquist criterion (which is almost certainly true) sez that the > sampling rate should be at least 2 times the highest freq. to be measured. > Local events have a lot of information in the higher freqs., say up to 10 > Hz, so sampling at at least 20/sec would be required. > Teleseismic events have little energy above 0.1 Hz so a sampling rate of > 1 Hz would be more than enough. I use 1 sample/sec. and get very good > recordings. Of course, a low pass filter before the A/D is required and > it should allow very little energy to pass which is above 1/2 the sampling > freq. I use a filter with a knee at 0.08Hz. > I also have a Radio Shack DMM with the RD-232 interface and find it very > handy for a variety of jobs (e.g., battery discharge curves) and mine will > get > 2 samps/sec. The main problem with it for seis. work is the dynamic > range. The largest number it will record is 2,000. So if you set your > amp. gain to get say 20 counts with the seismic background, the largest > 'quake you can see without clipping would have a signal/noise ratio of only > 100. I have gotten a fair number which exceed that. Larry's board has a > 16 bit A/D which has a max. count of 65,000 which is almost always > adequate. > Another major problem with the RS DMM is that is not compatible with SDR. > SDR is great for many reasons not the least of which is that the record > can be displayed and analyzed by WINQUAKE. > Bob Barns > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: Minimum sampling rate. Date: Thu, 27 Nov 1997 08:21:05 -0600 Robert Avakian wrote: > > A different idea on the entire signal recording problem was used by a > geophysical contractor a number of years ago and was called sign bit > recording. They wanted to add channles of recorders so they did away > with the bulk of the A/D process and recorded just the sign of the > amplitude of the geophone signal (1 bit per sample) albeit at a higher, > "over sampled" rate. Integrating the data recovered the waveform. The > results were accurate and, on the whole, removed concern over recording > satbility, amplifier performance, electronic noise, and accuray in A/D. > I wonder if this would hold any advantages to our work? > > Unfortunately I for get the company's name but I am sure one could hunt > up some atricles in old issues of Geophysica, the journal of the SEG. > > Bob Avakian > Robert, You have essentially described the operation of the Sigma/Delta A/D converter. Enexpensive ICs that do this function are avaliable from at least Linear and Burr Brown. Other unique advantages are that because of the extreme oversampling no or a very minimal antialias filter is required. It is possible to adjust the sampling rate so that 60 or 50 HZ falls in a deep null of the devices response. You can get about 20 bits of resolution out of the Burr Brown device and because of this not much or no preamp would be required. The recent Geo Monitor newsletters have a seismograph construction article using the BB device. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Doug Crice Subject: Re: Minimum sampling rate. Date: Thu, 27 Nov 1997 09:34:27 -0800 Sign-bit recording was developed in the 1970's and used for petroleum exploration. Instead of an A/D converter, the input is just a comparator with an output of 1 or 0. It's not the same as delta-sigma A/D conversion. Sign-bit recording only worked well with a vibroseis energy source. A vibroseis is a large, truck-mounted shaker that vibrates the ground with a swept frequency, typically 10 to 80 Hz or so for about 15 seconds. They are typically used in groups of say 4 vehicles synchronized together, and you can really feel the ground shake. The seismic recording system runs for about 20 seconds, recording what looks like random noise. When the record is cross-correlated with the recorded sweep signal, the output looks just like a record from an impulsive source (e.g. dynamite). You get away with recording only one bit because the correlation process combines thousands of these creating a record with a usable number of bits. Sam Allen of Geophysical Systems in Pasadena invented the process and them spent years convincing the petroleum industry that it actually worked. Unfortunately, time and technology passed him by. The principle advantage of sign-bit recording is that the A/D comverter (a comparator) was quite cheap compared to A/D converters with lots of bits, and it became feasible to make seismic recording systems with thousands of channels. By the time sign-bit became accepted, A/D converters got cheap, and the fundamental economic basis has passed by. Sam also preceded the wide acceptance of 3D seismic (a surface grid instead of lines), so he was double ahead of his time. Anybody want to know more, just ask. Doug Crice _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: Force of Lehman susp. wire Date: Thu, 27 Nov 1997 18:57:09 +0000 Karl Cunningham wrote: ............snip........ Another problem is that the longer the period, the more sensitive the > system is to the mechanical stability of the base and mast. I haven't done > any calculations on this recently, but I beleive a Lehman adjusted for 30 > seconds presents quite a challenge in this regard. Hi Karl,I can confirm that over 30 secs becomes an 'art ' . My horizontals are made in 1" section steel, (AND braced as well!!!). The seismos weigh in at 60 lbs. so are quite massive and stable. As I recently posted to PSN, my experience has been that to achieve 60 sec period, (which I am determined to do!!), piano wire, if used, must NOT be allowed to bend. ( As I have found here, this does make 30 sec + periodicity, difficult to attain.). Rolling, knife edges etc., OR our old favourite on PSN at present ...spider wire fish line etc. etc. will help in this end. If one is not prepared to put in heavy and good engineering work into a PLAIN STANDARD hor. seismo, then 30 sec plus will be out of reach. (One only has to look at the older professional seismos to appreciate this.) The other geometry which MUST be maintained for stable working at these long swing rates, is that looking at the seismo with beam pointing at you, the suspension top anchorage MUST be well 'defined', and MUST be accurately maintained truly vertical above pivot. A few thou variation, (because the vertical offset is so small), represents such a large angular diversion of the beam....I'm sure many have cursed, as their beams have destabilised to one side or the other, just because, in slightly adjusting the leveling, has caused this verticality to become slightly lost. That's my experience to date.... (Those using electronic wizardry to attain long periodicities, may not have these troubles ). Regards, Albert Noble (England). > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Ron James" Subject: Re: What does it all mean? Date: Thu, 27 Nov 1997 13:17:46 -0600 Hi Berry, I tried the URL listed by Walt and had the same problem but I kept trying and I found it. Try this. Go to http://www.sti.nasa.gov/RECONselect.html once there, do a search on the text "Artificial neural networks for seismic data interpretation". You will get an answer. 73's de Ron/N6SZC Marble Falls, TX. -----Original Message----- From: barry lotz To: PSN-L Mailing List Date: Wednesday, November 26, 1997 9:58 PM Subject: Re: What does it all mean? >Walt > I couldn't seem to go to the location you show from Netscape. >Any thoughts. > Barry > >Walt Williams wrote: >> >> Hello All, >> >> I came across interesting abstract titled: >> "Artificial neural networks for seismic data interpretation" >> > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Ron James" Subject: Re: What does it all mean? Date: Thu, 27 Nov 1997 13:43:10 -0600 Walt, check out the report Titled: Real-time classification of signals from three-component seismic sensors using neural nets. I think you'll find your answer. Ron/N6SZC Marble Falls, TX. -----Original Message----- From: Walt Williams To: PSN-L Mailing List Date: Wednesday, November 26, 1997 6:03 PM Subject: What does it all mean? >Hello All, > >I came across interesting abstract titled: >"Artificial neural networks for seismic data interpretation" > >at: > >http://www.sti.nasa.gov/cgi-bin/waisgate?WAISdocID=8510327954+9+ >0+0&WAISaction=retrieve&WAISlogFile=/home3/wais/waislog > >Best Regards, > >Walt Williams, 97.11.26 >dfheli@.............. > >Woodland Hills, (LA suburb), California >USA > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Test Date: Thu, 27 Nov 1997 18:11:21 -0800 Test to see if alternate form of adress will go thru. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: Minimum sampling rate. Date: Thu, 27 Nov 1997 20:30:09 -0600 Doug Crice wrote: > > Sign-bit recording was developed in the 1970's and used for petroleum > exploration. Instead of an A/D converter, the input is just a > comparator with an output of 1 or 0. It's not the same as delta-sigma > A/D conversion. > > Sign-bit recording only worked well with a vibroseis energy source. A > vibroseis is a large, truck-mounted shaker that vibrates the ground with > a swept frequency, typically 10 to 80 Hz or so for about 15 seconds. > They are typically used in groups of say 4 vehicles synchronized > together, and you can really feel the ground shake. > > The seismic recording system runs for about 20 seconds, recording what > looks like random noise. When the record is cross-correlated with the > recorded sweep signal, the output looks just like a record from an > impulsive source (e.g. dynamite). > > You get away with recording only one bit because the correlation process > combines thousands of these creating a record with a usable number of > bits. > > Sam Allen of Geophysical Systems in Pasadena invented the process and > them spent years convincing the petroleum industry that it actually > worked. Unfortunately, time and technology passed him by. The principle > advantage of sign-bit recording is that the A/D comverter (a comparator) > was quite cheap compared to A/D converters with lots of bits, and it > became feasible to make seismic recording systems with thousands of > channels. > > By the time sign-bit became accepted, A/D converters got cheap, and the > fundamental economic basis has passed by. Sam also preceded the wide > acceptance of 3D seismic (a surface grid instead of lines), so he was > double ahead of his time. > > Anybody want to know more, just ask. > > Doug Crice I defer to Doug's expertise in Seismic data acquisition. I had to go back and reread the Burr Brown info on their converters. The basic concept of digitizing to only one bit (sign bit) at a high rate and then summing to get more bits of resolution is part of the delta-sigma concept but not the correlation with the source signal or the recording of just the sign bit. In the delta-sigma converter the summed result would be what one would record. All that aside I think the delta-sigma converter such as the Burr Brown ADS1210 would make an idea digitizer for a seismometer. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: Force of Lehman susp. wire Date: Thu, 27 Nov 1997 20:59:27 -0800 George Harris wrote: ... > Flexure pivots can be used in pure tension if the geometry is correct. > The secret is to have the flexure element attachment points tilted in > such a way that their extensions would meet at the center of gravity of > the mass system. > > As an example, assume that the pivots are on the left, and the mass > on a beam to the right. The lower pivot could be horizontal, that > is the attachment points of the flexure are on a horizontal line and > aligned with the beam. The fixed lower support is to the right > of the attachment to the beam. That is, the beam must pass around > the support and have its attachment to the left of the support. The > mass will then cause this flexure to be in tension. ..... George, You reinforced my comment that I still don't know how to accomplish the problem with flexures. I suppose I need to clarify my comment. One of the requirements (at least I think so) for the boom pivots is that the axis of the swing is coaxial for the two pivots and that axis is almost vertical (which causes the weight of the boom to describe a very shallow arc leading to the equivalent long period pendulum of long length). Your description of the bottom pivot has the flex axis almost horizontal and the upper pivot will have the axis perpendicular to the tension vector (aimed basically at the weight at the end of the arm.) Actually I would think that the bottom pivot is almost vertical because the boom basically "pushes" the weight away from the lower pivot, while the upper pivot is in tension trying to keep the weight from "falling"using a connection (the boom wire or suspension). But as a consequence, neither pivot is either vertical or horizontal. Now when the boom begins to swing, it will cause the top pivot in particular to go into twist as it would be at the greatest angle to the vertical, This twist wrap-up would be equivalent to shortening the boom pivot, and thereby shortening the period. Karl Cunningham wrote: .... >The "hinge point" will not necessarily be where the flexures cross, but I >think it won't change as the boom swings. Karl, I think that the pivot point travels a curved (hyperbolic?) path in the crossed pivot. Imagine that you really move it a bunch, then draw the flexures. I just took a pair of tongue depressors with wire standing in for the flexures and ran the experiment. It becomes very obvious that the pivot point moves! But just as an insight, draw the following pictures. Picture one is just as you drew the flexure. Picture shows the start of the rotation of 3/4. Picture three has completed the rotation of the 3/4 180 degrees. It has displaced and turned around . If you were to plot the intersection of the perpendiculars to the parts 1/2 and 3/4 you will see the curve goes to infinity. That means the pivot point moved toward the boom weight if the weight is on the same side as the pivot (such as 3/4). But that would be trying to use the flexure in compression, so if put in tension, i.e., 1/2 is between the weight and its pivot 3/4, then the axis point would be moving away. Now since the upper pivot would be normal in tension, its pivot axis would be moving toward the weight. This means that the vertical axis that the boom swings around is tipping in the direction of the weight and falling over to the side as the two pivots move. Which dominates I leave as an experiment for the student! (I.e., I don't know either.) 1========2 1========2 1========2-----------\ \ a / \ a | \-----------4========3 \ / \ | b \ / \ | \/ - |-\ /\ | \ / \ | b \ / \ | ====4 / b \ 3==== 3========4 Charles R. Patton, Editor, Geo-Monitor home: 909-698-9657 work 714-932-7476 fax:909-698-0224 email: patton@......... Geo-Monitor homepage: http://iinet.com/users/patton _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Doug Crice Subject: Delta-Sigma A/D converters Date: Thu, 27 Nov 1997 21:28:55 -0800 I agree that delta sigma is the converter of choice: You get more bits, lower harmonic distortion, more dynamic range. There's some pretty cheap ones out that were developed for audio, but probably the analog devices is the best for earthquake seismic. You get a built-in digital anti-alias filter, a real one, not one of those compromise anti-alias filters with just a few poles For a data sheet, check the Analog Devices home page at http://www.analog.com/products/selection_trees/highres_sigma/highres_sigma_ads_24.html If folks start using more than 16 bits, does the software have to be updated? Doug Crice _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Doug Crice Subject: Delta Sigma Converter Date: Thu, 27 Nov 1997 21:34:43 -0800 Excuse me, the Burr Brown AD1210 unit looks good too, maybe better than the Analog Devices unit. See it at http://www.burr-brown.com/Products/DataSheets/ADS1210.html Doug Crice _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Liberio Rossi Subject: Seismic signal sent by radio stations Date: Fri, 28 Nov 1997 14:48:18 +0100 Hi all, No one of the gang knows is some radio station is sending sismic signals ..this because it should be a simply way to compare our reception of the seismic signal in order to know much better what we are doing with our seismographs. I am a Radioamateur and my call is I 5 WC. My full name is Liberio Rossi ( liberio.rossi@......... Awaiting news from all the world have all my best regards Liberio _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: Force of Lehman susp. wire Date: Thu, 27 Nov 1997 21:42:53 -0800 Karl & Albert It seems that if a Lehman has a displacement measuring sensor in addition to the coil, one could keep track of the boom location. It might then be possible to provide a current offset to the coil or a second coil to keep the coil near the center. I don't think it would work quite the same as a force feedback system in that the sensor is allowed to move as the offset current to the coil is to compensate only for the slight horizontal component of gravity due to tilting. Barry prewar wrote: > > Karl Cunningham wrote: > ...........snip........ > Another problem is that the longer the period, the more sensitive the > > > system is to the mechanical stability of the base and mast. I haven't done > > any calculations on this recently, but I beleive a Lehman adjusted for 30 > > seconds presents quite a challenge in this regard. > ....I'm sure many have cursed, as their beams > have destabilised to one side or the other, just because, in slightly > adjusting the leveling, has caused this verticality to become slightly lost. > > That's my experience to date.... (Those using electronic wizardry to > attain long periodicities, may not have these troubles ). > > Regards, > > Albert Noble (England). > > > > > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Attenuation and velocity in all. basins Date: Fri, 28 Nov 1997 11:47:48 -0700 (MST) Hello Everyone, I am looking for references/information on seismic attenuation and velocity in alluvial basins. I would also be interested in finding any relationship between clast size and shape in these quantities. ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: lahr@.................. Subject: travel-time graph Date: Fri, 28 Nov 1997 13:51:19 -0700 (MST) I scanned a travel-time table and put it on my web page at: http://www.giseis.alaska.edu/Input/lahr/tttable.gif This is a graph of arrival time in minutes versus distance in degrees for various phases, based on the JB tables. It's a bit hard to read, but better than nothing. Does anyone know of a cleaner version of this chart on the web somewhere? Thanks, JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: Delta-Sigma A/D converters Date: Fri, 28 Nov 1997 13:38:46 -0700 At 09:28 PM 11/27/97 -0800, Doug Crice wrote: >I agree that delta sigma is the converter of choice: > > You get more bits, lower harmonic distortion, more dynamic range. > > There's some pretty cheap ones out that were developed for audio, but >probably the analog devices is the best for earthquake seismic. > > You get a built-in digital anti-alias filter, a real one, not one of >those compromise anti-alias filters with just a few poles > > For a data sheet, check the Analog Devices home page at > >http://www.analog.com/products/selection_trees/highres_sigma/highres_sigma_ ads_24.html > > If folks start using more than 16 bits, does the software have to be >updated? Yes it would. The current PSN event file format uses a 16 bit array. If you want to use the current PSN format you would have to truncate the lower bits. Since WinQuake can read SAC binary or PEPP format event files you could use them. Both use floating point numbers for the data. Unfortunately both lack the comment and station location string, something I real like about the PSN format. I think this is going to be one of the agenda items for our local PSN meeting. We need to come up with a new format and I think the meeting would be a good time to finalize it. In a few days I will start a tread on this list asking for peoples input for the new format. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Francesco" Subject: TELESESIM Date: Sat, 29 Nov 1997 00:50:40 +0100 Hi all, The italian stations have recorded this event: 23.07 utc dist. >=9.500 km Mg. 6.8 preliminary location: SudAmerica Did anyone chek this event? Francesco Nucera Osimo - Ancona - Italy _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: TELESESIM - PERU-BOLIVIA BORDER REGION Date: Fri, 28 Nov 1997 16:01:39 -0700 Heres the NEIC info on the event. I got a good P and S wave but no surface waves do to its depth. 97/11/28 22:53:42 13.44S 68.78W 585.6 6.3Mb A PERU-BOLIVIA BORDER REGION -Larry Cochrane At 12:50 AM 11/29/97 +0100, Francesco Nucera wrote: >Hi all, >The italian stations have recorded this event: > >23.07 utc >dist. >=9.500 km >Mg. 6.8 >preliminary location: SudAmerica > >Did anyone chek this event? > >Francesco Nucera >Osimo - Ancona - >Italy _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: Force of Lehman susp. wire Date: Fri, 28 Nov 1997 20:19:25 -0600 barry lotz wrote: > > Karl & Albert > It seems that if a Lehman has a displacement measuring sensor in > addition to the coil, one could keep track of the boom location. It > might then be possible to provide a current offset to the coil or a > second coil to keep the coil near the center. I don't think it would > work quite the same as a force feedback system in that the sensor is > allowed to move as the offset current to the coil is to compensate only > for the slight horizontal component of gravity due to tilting. > Barry > Barry, This is the direction I am headed with my Lehman. A LVDT will provide the displacment information to a lopass filter with a cutoff of about ..01 Hz. This signal will be used to keep the boom centered. An attempt will also be made to do the damping electrically by differentiating the displacment and feeding this back to the same coil. I may end up with a big mess but I think it is worth a try. You can record either the displacment output of the LVDT or to stay the same as a traditional Lehman the differentiated output of the LVDT. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: Force of Lehman susp. wire Date: Sat, 29 Nov 1997 10:27:28 +0000 Jim Hannon wrote: > barry lotz wrote: > > > > Karl & Albert > > It seems that if a Lehman has a displacement measuring sensor in > > addition to the coil, one could keep track of the boom location. It > > might then be possible to provide a current offset to the coil or a > > second coil to keep the coil near the center. I don't think it would > > work quite the same as a force feedback system in that the sensor is > > allowed to move as the offset current to the coil is to compensate only > > for the slight horizontal component of gravity due to tilting. > > Barry > > > Barry, > This is the direction I am headed with my Lehman. A LVDT will provide > the displacment information to a lopass filter with a cutoff of about > .01 Hz. This signal will be used to keep the boom centered. An attempt > will also be made to do the damping electrically by differentiating the > displacment and feeding this back to the same coil. I may end up with a > big mess but I think it is worth a try. You can record either the > displacment output of the LVDT or to stay the same as a traditional > Lehman the differentiated output of the LVDT. > Hi,Just a quick thought....Shouldn't the lowpass filter be of a narrow bandpass design, whose centre freq. is centred EXACTLY on the period of the beam? (But perhaps your beam is a 10 sec period for your .1 Hz filter mentioned?) Regards, Albert Noble (England) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: Force of Lehman susp. wire Date: Sat, 29 Nov 1997 07:49:39 -0600 prewar wrote: > > Hi,Just a quick thought....Shouldn't the lowpass filter be of a narrow > bandpass > design, whose centre freq. is centred EXACTLY on the period of the beam? > (But perhaps your beam is a 10 sec period for your .1 Hz filter mentioned?) > Regards, > Albert Noble (England) The filter I will use is .01 HZ which is equavalent to 100 second period. The idea here is to get the effect of the filter completely out of the way of the effect of the beam resonance. Filters tend to mess with the phase of the signals and one would very likely end up with an oscilator of some sort if the two frequencies were near each other. Another way of looking it is this arrangment will only remove movements of the boom that are longer in period than 100 sec. In otherwords long term drift ect. A band pass filter is very messey phase wise. There would also be problems with keeping it matched with the boom resonance. The damping is a separate function. For damping the velocity of the boom is computed by the differentiator and used to oppose the beam motion. This is the same thing that happens with oil or magnetic damping. The faster the boom is moving the more force is opposing the movement. - Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Al Allworth Subject: Boom position feedback Date: Sat, 29 Nov 1997 11:57:35 -0800 (PST) At 07:49 AM 11/29/97 -0600, you wrote: >prewar wrote: >> >> Hi,Just a quick thought....Shouldn't the lowpass filter be of a narrow >> bandpass I have thought for some time that the best way to take care of boom position feedback would be through the software feeding back through a D to A to the compensating coil. This would allow for complete control of the feedback and tayloring of the response to perfectly match the mechanical characteristics. Any thoughts? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: Boom position feedback Date: Sat, 29 Nov 1997 03:52:45 -0800 Al et al ($0.02) It seems to me that the offset reading from the displacement sensor could be feed to a second very low gain amp/coil to provide a "constant" looooow restoring force. I agree with previous comments that the signal would have to be low passed to prevent the seismic event from influencing the restoring coil. I agree that a D/A would also work if the system has one. The output would have to be low to prevent overshooting. Barry Al Allworth wrote: > > At 07:49 AM 11/29/97 -0600, you wrote: > >prewar wrote: > >> > >> Hi,Just a quick thought....Shouldn't the lowpass filter be of a narrow > >> bandpass > > I have thought for some time that the best way to take care of boom position > feedback would be through the software feeding back through a D to A to the > compensating coil. This would allow for complete control of the feedback and > tayloring of the response to perfectly match the mechanical characteristics. > Any thoughts? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Time! Date: Sat, 29 Nov 1997 03:59:58 -0800 Larry et al I apologize for this low power question. I was trying to understand how a WWWV time signal gets to the computer input. I realize tha Larry's hardware has the capability but I was trying to put together a compact low power remote station and also I don't have a scanner or GPS system. I was hoping to use an AM radio and Ramsey shortwave converter. Any help to the radio ignorant would be appreciated. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: Attenuation and velocity in all. basins Date: Sat, 29 Nov 1997 16:15:48 -0700 John- This is one of the $64,000 (maybe it's gone up recently) questions of my business in seismology, especially since Northridge Earthquake. In principle, this information can be used to predict the site response of the areas in question. Differences of response between rock and unconsolidated sediments can be associated with corresponding differences of material propperties such as velocity and attenuation. However, it is often difficult to obtain complete information about the variation of velocity and attenuation of sediments that correlates well with observed variations of site response. See http://geohazards.cr.usgs.gov/engnseis/Eshmpage/ofr96-273/ofr96-273.htm -Edward John Hernlund wrote: > > Hello Everyone, > I am looking for references/information on seismic attenuation and > velocity in alluvial basins. I would also be interested in finding any > relationship between clast size and shape in these quantities. > > ****************************************************************************** > > John Hernlund > E-mail: hernlund@....... > WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ > > ****************************************************************************** > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Time! Date: Sun, 30 Nov 1997 11:34:24 +1200 taking audio from the radio headphone/earphone jack to the appropriate input pin of the SDR board Pin 36 Dave At 03:59 AM 11/29/97 -0800, you wrote: >Larry et al > I apologize for this low power question. I was trying to understand >how a WWWV time signal gets to the computer input. I realize tha Larry's >hardware has the capability but I was trying to put together a compact >low power remote station and also I don't have a scanner or GPS system. >I was hoping to use an AM radio and Ramsey shortwave converter. Any help >to the radio ignorant would be appreciated. > Barry > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Student Desires Interview with Geologist Date: Sat, 29 Nov 1997 20:29:44 -0800 Greetings, all -- My daughter is in ninth grade and one of her assignments in school is to speak with several professionals in a field of study of her choice about what the profession is like. The field she has chosen is geology, and I said I would help her get in touch with some geologists. If any geologists out there would like to spend about five minutes on the phone with her to answer some questions about your work (or know of someone else who would), please let me know by private email; I'll get the two of you in touch with each other. She needs to complete the assignment by Friday, Dec 5. Thanks very much. Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: Attenuation and velocity in all. basins Date: Sat, 29 Nov 1997 23:49:31 -0700 (MST) On Sat, 29 Nov 1997, Edward Cranswick wrote: > John- > This is one of the $64,000 (maybe it's gone up recently) questions of > my business in seismology, especially since Northridge Earthquake. In > principle, this information can be used to predict the site response of > the areas in question. Differences of response between rock and > unconsolidated sediments can be associated with corresponding > differences of material propperties such as velocity and attenuation. > However, it is often difficult to obtain complete information about the > variation of velocity and attenuation of sediments that correlates well > with observed variations of site response. See > http://geohazards.cr.usgs.gov/engnseis/Eshmpage/ofr96-273/ofr96-273.htm > -Edward Edward, I enjoyed reading the page. It seems to be a problem which might be solved doing local refraction surveys (I have never done a large scale refraction survey so I am not sure of its limitations)? Has anyone ever tried this? It would be interesting to see the results, especially if any drilling was done afterwards to correlate the velocity specific layers with an actual sample of each. I am sure that there are many areas that have already been drilled so that half of the experiment would be complete. ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Re: Minimum sampling rate. Date: Sun, 30 Nov 1997 10:09:09 -0500 Bob Avakian, A truly fascinating idea esp. for those recording many channels at high= sampling rates. I don't have that problem since I have only 1 channel an= d use 1 samp/sec. I have simulated this with a GWBASIC program. Very interesting. I can= send the prog. to anyone who would like to fool with it. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Re: Minimum sampling rate. Date: Sun, 30 Nov 1997 10:09:10 -0500 Norman, You should amplify the signal until you get 5 or 10 least counts from t= he seismic noise on a quiet day. It should be either a DC amp. or one with = a hi-pass cut-off at something like 0.01Hz. Bob Barns KB2IKC _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: What does it all mean? Date: Sun, 30 Nov 1997 10:09:12 -0500 Walt, One meaning is that a new record for long URL's has been set. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Re: Minimum sampling rate. Date: Sun, 30 Nov 1997 08:08:34 At 10:09 AM 11/30/97 -0500, you wrote: >Norman, > You should amplify the signal until you get 5 or 10 least counts from the >seismic noise on a quiet day. It should be either a DC amp. or one with a >hi-pass cut-off at something like 0.01Hz. >Bob Barns >KB2IKC This has got to be one of the longest running threads. So if I do bandpass it should be low=.01HZ and high say =20HZ. Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: Boom position feedback Date: Sun, 30 Nov 1997 09:22:52 -0800 At 03:52 AM 11/29/97 -0800, you wrote: >Al et al >($0.02) It seems to me that the offset reading from the displacement >sensor could be feed to a second very low gain amp/coil to provide a >"constant" looooow restoring force. I agree with previous comments that >the signal would have to be low passed to prevent the seismic event from >influencing the restoring coil. I agree that a D/A would also work if >the system has one. The output would have to be low to prevent >overshooting. > Barry Barry & others-- There may be a potential snag with sending the feedback through a low-pass filter. The phase shift through a low-pass filter approaches 90 degrees lag per pole past its cutoff frequency. If the gain around the loop (including the mechanical system) is more than unity, it will oscillate when the phase shift around that same loop reaches 180 degrees. And there is undoubtedly already a phase shift in the loop associated with the feedback coil's force on the mass. I would suggest that if you run into these problems, don't be afraid to play with a differential feedback component. C1 in the following circuit feeds more signal to the feedback coil when the position is changing, and since the feedback coil is opposing the movement, this will tend to reduce lagging phase shift and associated overshoot/oscillations. It is usually necessary to put a resistor in series with C1 to limit its influence at higher frequencies. Sometimes higher-order differential feedback (more stages) is required to stabilize the loop. C1 R2 +---||---+---\/\/\----+ | | | From | | |\ | Position | R1 | | \ | Sensor ------+--\/\/\-+-|- \ | | >----+--- To Feedback Coil +---|+ / | | / | |/ --- \ / V Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Donald Sieber Subject: quake Date: Sun, 30 Nov 1997 14:49:21 -0800 Did you folks near Mammoth lakes just have another 4+ quake at 21:17 ut? None of the reporting stations seem to be working at the present time (22:48 UT) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Marnie Gannon Subject: Mammoth Date: Sun, 30 Nov 1997 16:23:43 -0700 Yes, it's at the top of the list on the CNSS list..only a "C" location. I can't get into the USGS sites..Looks like things have picked up again. Marnie 97/11/30 21:17:04 37.64N 118.96W 0.9 4.8Ml C* 1 mi SE of Mammoth Lake NC 97/11/30 21:20:44 37.65N 118.89W 10.4 2.7MD C* 5 mi E of Mammoth Lake NC 97/11/30 21:23:38 37.64N 118.93W 5.7 2.6MD B* 2 mi ESE of Mammoth Lake NC 97/11/30 21:24:38 37.65N 118.96W 4.1 2.1Ml B* 0 mi ESE of Mammoth Lake NC 97/11/30 21:25:24 37.63N 118.95W 7.2 2.4MD A* 1 mi SE of Mammoth Lake NC 97/11/30 21:26:03 37.64N 118.95W 8.1 3.0Ml A* 2 mi SE of Mammoth Lake NC 97/11/30 21:28:53 37.63N 118.93W 5.7 2.2MD B* 3 mi ESE of Mammoth Lake NC 97/11/30 21:30:14 37.64N 118.95W 9.1 2.5MD A* 1 mi SE of Mammoth Lake NC 97/11/30 21:32:18 37.64N 118.92W 6.0 2.2MD A* 3 mi ESE of Mammoth Lake NC 97/11/30 21:34:59 37.64N 118.94W 4.8 2.1Md 1* 3 km ESE of Mammoth Lake BK 97/11/30 21:37:16 37.64N 118.95W 5.1 2.6MD B* 2 mi ESE of Mammoth Lake NC 97/11/30 21:38:21 37.63N 118.92W 5.3 2.3Md 0* 4 km ESE of Mammoth Lake BK 97/11/30 21:39:29 37.64N 118.95W 5.2 2.9MD A* 1 mi ESE of Mammoth Lake NC 97/11/30 21:40:17 37.64N 118.94W 7.8 2.1MD B* 2 mi ESE of Mammoth Lake NC 97/11/30 21:42:59 37.64N 118.95W 7.9 2.1MD A* 1 mi ESE of Mammoth Lake NC 97/11/30 21:44:03 37.64N 118.95W 5.2 2.2MD B* 1 mi ESE of Mammoth Lake NC 97/11/30 21:45:54 37.62N 118.99W 6.7 2.5MD B* 2 mi SSW of Mammoth Lake NC 97/11/30 21:50:45 37.63N 118.93W 5.3 2.2MD A* 3 mi ESE of Mammoth Lake NC 97/11/30 22:03:23 37.64N 118.94W 5.7 2.3Md 1* 3 km ESE of Mammoth Lake BK 97/11/30 22:06:05 37.63N 118.95W 2.9 2.1Md 1* 3 km SE of Mammoth Lake BK 97/11/30 22:09:45 37.64N 118.92W 4.9 3.0Ml 0* 5 km ESE of Mammoth Lake BK 97/11/30 22:12:57 37.63N 118.93W 4.7 2.6Md 1* 4 km ESE of Mammoth Lake BK _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Norm L'Heureux" Subject: Re: quake Date: Sun, 30 Nov 1997 15:26:49 -0800 At 02:49 PM 11/30/97 -0800, you wrote: Here is some info. on the quake. A LIGHT EARTHQUAKE OCCURRED AT 01:17 PM PST Sunday, Nov 30, 1997. THE MAGNITUDE 4.8 (ML) EVENT IS LOCATED 1 MILES SE OF MAMMOTH LAKES, CA THE HYPOCENTRAL DEPTH IS 0.6 MILES. PRINCIPAL EARTHQUAKE PARAMETERS _______________________________ Magnitude : 4.83 ML Event Date & Time : 11/30/1997 01:17:04 PM PST 11/30/1997 21:17:04 UTC Location : 37.6367 N, 118.9592 W : (37 deg. 38.20 min. N, 118 deg. 57.55 min. W) Depth : 1.0 km. deep ( 0.6 miles) Location Quality : Fair 2 km ( 1 miles) SE (140 degrees) of Mammoth Lakes, CA 26 km ( 16 miles) WNW (289 degrees) of Toms Place, CA 38 km ( 24 miles) SSE (158 degrees) of Lee Vining, CA 57 km ( 36 miles) ESE (102 degrees) of Yosemite Village, CA 58 km ( 36 miles) WNW (302 degrees) of Bishop, CA >Did you folks near Mammoth lakes just have another >4+ quake at 21:17 ut? None of the reporting stations >seem to be working at the present time (22:48 UT) > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: quake Date: Sun, 30 Nov 1997 16:43:58 -0800 (PST) Hello All: Yes, and they're getting closer to the surface! Maybe, Dr. Hill (USGS)will now change the alert status to the "Yellow" condition. I think it is a shame when commercial interests are put ahead of the general safety of the public at large. This is a flagrant example of this! It's a good thing that they didn't get an even larger quake and that half of the people have probably left that were visiting for the long weekend before this latest event struck. Well, it's just a matter of time before someone gets hurt if they don't do something to protect them. Frank Condon Mail to:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" >At 02:49 PM 11/30/97 -0800, you wrote: >Here is some info. on the quake. >A LIGHT EARTHQUAKE OCCURRED AT 01:17 PM PST Sunday, Nov 30, 1997. >THE MAGNITUDE 4.8 (ML) EVENT IS LOCATED 1 MILES SE OF MAMMOTH LAKES, CA >THE HYPOCENTRAL DEPTH IS 0.6 MILES. > >PRINCIPAL EARTHQUAKE PARAMETERS >_______________________________ > >Magnitude : 4.83 ML >Event Date & Time : 11/30/1997 01:17:04 PM PST > 11/30/1997 21:17:04 UTC >Location : 37.6367 N, 118.9592 W > : (37 deg. 38.20 min. N, 118 deg. 57.55 min. W) >Depth : 1.0 km. deep ( 0.6 miles) >Location Quality : Fair > > 2 km ( 1 miles) SE (140 degrees) of Mammoth Lakes, CA > 26 km ( 16 miles) WNW (289 degrees) of Toms Place, CA > 38 km ( 24 miles) SSE (158 degrees) of Lee Vining, CA > 57 km ( 36 miles) ESE (102 degrees) of Yosemite Village, CA > 58 km ( 36 miles) WNW (302 degrees) of Bishop, CA > >>Did you folks near Mammoth lakes just have another >>4+ quake at 21:17 ut? None of the reporting stations >>seem to be working at the present time (22:48 UT) >> >> >>_____________________________________________________________________ >> >>Public Seismic Network Mailing List (PSN-L) >> >>To leave this list email listserver@............. with the body of the >>message: leave PSN-L >> > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Robert L. Hancock" Subject: Mammoth Tilt Data Date: Sun, 30 Nov 1997 21:25:49 -0500 During last weeks series of quakes, and again following the recent activity today, there were significant changes visible in both the shortbase tilt data base and the longbase tilt data base. These seem to indicate some change in the land shape. Where can I find something written for a non-geologist that would explain the significance of these two data bases, and what their differences are. Are these changes really significant, or are they measurements of such small changes as to be insignificant. Somebody please advise. Thanks, Bob Hancock _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Mammoth M4.8 Quake Date: Sun, 30 Nov 1997 18:42:30 -0700 This Seismo-Watch Earthquake Alert Bulletin was issued earlier this afternoon: +=*+=*+=*+=*+=*+=*+=*+=*+=*+=*+=*+=*+=*+=*+=*+=*+=*+=*+=*+=*+=*+=*+=*+=* MAMMOTH LAKES, CALIFORNIA 4.8 ML (NCSN) n/a Mw ( -- ) 97/11/30 21:17:04 (1:17 P.M. PST) 37.64N 118.96 1 km A --------- Notations: An earthquake registering a preliminary magnitude of ML 4.8 occurred at 21:17 UTC (1:17 p.m.), November 30, at Mammoth Lakes, California. The quake was centered about 1 mile southeast Mammoth Lakes, the closest of the four M4's to occur in the area during the 1997 Mammoth Lakes Earthquake Swarm. The focal depth was shallow, only 1 km (0.6 miles) beneath the surface. Preliminary reports indicate the quake shook the region quite sharply, but there have been no reports in damage or injuries. No avalanches were observed. A vigorous swarm sequence has followed and during the 2 p.m. hour, more than 80 quakes/hour were detected – a the highest rate of seismicity ever recorded at Mammoth Lakes! The activity has stayed very high, but dropped back to 62 quakes/hour during the 3 p.m. and 4 p.m. hours. Most of the activity has registered less M2 or less, but four events have been recorded in the M3 range. Three quakes in the M4+ range (M4.5, M4.8 and M4.7) occurred here on November 22, with peak seismic rates reaching 70 quakes/hour. The USGS has maintained a 24-hour watch at Mammoth Lakes since early November when activity topped the 500 events/week mark. The Volcanic Alert Status is still at the MODERATE UNREST or GREEN color code status level. The USGS maintains a color coded five-stage Volcanic Alert Status with the next stage, INTENSE UNREST or a YELLOW color code, triggered by a M5+ event or 40 M3’s/day. Deformation of the resurgent dome slowed during the past couple days and it will be interesting to watch the rates following this latest sequence. -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: NEIC Server back up Date: Sun, 30 Nov 1997 22:58:27 -0700 Looks like Sipken rebooted the server and its up and running again. Murphy's Law it should go down on a 4-day holiday, eh. -- ---/---- Charles _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Mammoth M4.8 Quake Date: Sun, 30 Nov 1997 23:56:25 -0800 (PST) Hello Charles: If you have them available, what is the statistical analysis over the last= =20 24 hours for the latest quakes near Mammoth Lakes? Is it anything like it=20 was on the 24th? Or, did this latest sequence die down more rapidly? Thanks, Frank Condon mail to: frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" >This Seismo-Watch Earthquake Alert Bulletin=20 >was issued earlier this afternoon: > >+=3D*+=3D*+=3D*+=3D*+=3D*+=3D*+=3D*+=3D*+=3D*+=3D*+=3D*+=3D*+=3D*+=3D*+=3D*= +=3D*+=3D*+=3D*+=3D*+=3D*+=3D*+=3D*+=3D*+=3D* > >MAMMOTH LAKES, CALIFORNIA > >4.8 ML (NCSN) > >n/a Mw ( -- ) > >97/11/30 =20 >21:17:04 (1:17 P.M. PST) >37.64N >118.96 >1 km >A =20 >--------- > >Notations:=20 > >An earthquake registering a preliminary magnitude of ML 4.8 occurred at >21:17 UTC (1:17 p.m.), November 30, at Mammoth Lakes, California. The >quake was centered about 1 mile southeast Mammoth Lakes, the closest of >the four M4's to occur in the area during the 1997 Mammoth Lakes >Earthquake Swarm. The focal depth was shallow, only 1 km (0.6 miles) >beneath the surface. Preliminary reports indicate the quake shook the >region quite sharply, but there have been no reports in damage or >injuries. No avalanches were observed. A vigorous swarm sequence has >followed and during the 2 p.m. hour, more than 80 quakes/hour were >detected =96 a the highest rate of seismicity ever recorded at Mammoth >Lakes! The activity has stayed very high, but dropped back to 62 >quakes/hour during the 3 p.m. and 4 p.m. hours. Most of the activity has >registered less M2 or less, but four events have been recorded in the M3 >range. Three quakes in the M4+ range (M4.5, M4.8 and M4.7) occurred here >on November 22, with peak seismic rates reaching 70 quakes/hour.=20 > >The USGS has maintained a 24-hour watch at Mammoth Lakes since early >November when activity topped the 500 events/week mark. The Volcanic >Alert Status is still at the MODERATE UNREST or GREEN color code status >level. The USGS maintains a color coded five-stage Volcanic Alert Status >with the next stage, INTENSE UNREST or a YELLOW color code, triggered by >a M5+ event or 40 M3=92s/day. Deformation of the resurgent dome slowed >during the past couple days and it will be interesting to watch the >rates following this latest sequence. > >--=20 >---/---- >Charles P. Watson, Consulting Geologist >Advanced Geologic Exploration >Seismo-Watch / Earthquake Information Services >Voice: 702-852-0992 / Fax: 702-852-3226=20 >Office Location: 39.43N 119.71W >mailto:watson@................ >http://www.seismo-watch.com > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the=20 >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: ERICH777@....... Subject: Unable to access sites Date: Mon, 1 Dec 1997 07:37:34 -0500 (EST) Hi I can't access sites with Mammoth or California & Nevada earthquake information. Anyone else with this problem? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Unable to access sites Date: Tue, 02 Dec 1997 00:45:23 +1200 yep the various USGS servers have been up and down like a yoyo..... just like last weekend..... murphy's law servers always crash in weekends when there is no-one around to reboot them Dave At 07:37 AM 12/1/97 -0500, you wrote: >Hi > >I can't access sites with Mammoth or California & Nevada earthquake >information. Anyone else with this problem? > Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Seismicty Rates @ Mammoth after M4.8 971130 Date: Mon, 01 Dec 1997 09:11:59 -0700 Here are the seismic rates at Mammoth following Sunday afternoon's M4.8 quake till 7 a.m. this morning local time: 971130 2100 1 pm M4.8 @ 1:17 p.m., 1-M3, 41 eq/hr 2200 2 pm 1-M3, 81 eq/hr 2300 3 pm 2-M3, 59 eq/hr 0000 4 pm 59 eq/hr 0100 5 pm 37 eq/hr 0200 6 pm 42 eq/hr 0300 7 pm 35 eq/hr 0400 8 pm 43 eq/hr 0500 9 pm 39 eq/hr 0600 10 pm 30 eq/hr 0700 11 pm 41 eq/hr 971201 0800 12 am 23 eq/hr 0900 1 am 26 eq/hr 1000 2 am 12 eq/hr 1100 3 am 10 eq/hr 1200 4 am 19 eq/hr 1300 5 am 21 eq/hr 1400 6 am 15 eq/hr 1500 7 am 19 eq/hr Seismic has dimminished considerably, however, still remains above the 300 events/day mark. No M3's since 2 hours after the main jolt. Best veiwed with a fixed font format (ie; Monaco, etc) and I hope the tab spacing comes out ok. If you would like to be on our fax service, call me or drop me an e-mail note. -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: fmurray@......... (frank murray) Subject: Re: Mammoth M4.8 Quake Date: Mon, 01 Dec 1997 18:42:20 GMT On Mon, 1 Dec 97 01:42:30 +0000, charles watson wrote: >........ The USGS maintains a color coded five-stage Volcanic Alert = Status >with the next stage, INTENSE UNREST or a YELLOW color code, triggered by >a M5+ event or 40 M3=92s/day.=20 does any one know if and where a precise wording of the usgs criteria for the varied stages might be found on the net??...the official usgs sites that i've browsed are rather vague in discussing those criteria...the above is the first mention of the 40 M3's/day as an alternate to an M5+ that i've seen mentioned... thanks, frank fmurray@......... for my electronic college proposal see: http://home.att.net/~fjtmurray/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Mexicali 3.6M Earthquake Date: Mon, 1 Dec 1997 11:24:44 -0800 (PST) Hello all: Could someone please tell me how far away was the recent 3.6M earthquake in Mexico from the Quarternary "Cerro Prieto" Volcano? Also, speculate "If Mammoth were to go active, then what are the chances that it would be the next one in the chain to become restless? 3.6 97/11/28 06:51:38 32.36N 115.31W 6.0 23 mi SSE of MEXICALI Thanks, Frank Condon mail to:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Mammoth M4.8 Quake Date: Mon, 01 Dec 1997 11:31:06 -0700 Frank- As you have probably seen... http://quake.wr.usgs.gov/VOLCANOES/LongValley/Response.html Response of the U.S. Geological Survey to episodes of unrest and the onset of possible volcanic activity in the vicinity of Long Valley caldera is described in Response Plans for Volcanic Hazards in the Long Valley Caldera and Mono Craters Area, California: U.S. Geo. Survey Open File Report 91-270, 64 p., 1991. Call them and have your VISA/MC card ready. The 40 M3's status change was obtained during a discussion with some of the seismologists at the USGS during the preceeding few weeks. They felt that a if a significant swarm were to develop and it contained 40 or more M3's, they would recommend to the CA OES a Volcanic Alert Status change. Obviously, the caldera has NOT reach this level of activity as of yet and does not warrant a status change. As they have said to me, this is a learning opperation, and they (the USGS and the CA OES) welcome comments from qualified members of the community. By the way, although a M4.8 quake did shake the region over the weekend, there was no hazard to the thousands of people visiting the area. There was no need to unjustly alarm people by prematurely issuing a YELLOW alert...as you called for earlier. They had a fine time and experienced a little bit of Mammoth take home with them and tell stories about to their relatives who stayed away in fear that the mountain was going to blow. Relax, relax..PVESD (Pre-Volcanic Eruption Stress Disorder) is curable given knowledge twice daily. Caution: Knowledge is habit forming. :> -- ---/---- Charlie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Mexicali 3.6M Earthquake Date: Mon, 01 Dec 1997 11:49:43 -0700 Frank Condon wrote: > > Hello all: > Could someone please tell me how far away was the recent 3.6M earthquake in > Mexico from the > Quarternary "Cerro Prieto" Volcano? Also, speculate "If Mammoth were to go > active, then what are the chances that it would be the next one in the chain > to become restless? > > 3.6 97/11/28 06:51:38 32.36N 115.31W 6.0 23 mi SSE of MEXICALI > The quake occurred pretty darn close to the Cerro Prieto volcano. The Mexican Government has allowed the development of a major geothermal power plant in the area to tap the thermal resource for producing electricity for their country and to sell to the Americans across the border. Seismicity is common in the area and has been the site of some significant swarms in the past. This past summer there was a robust swarm which consisted of a couple thousand of events over the course 6-weeks, including a dozen or so in the M3 range. The largest was M3.6, I think. Rarely, does activity get in the M4 range and less common above that. There was an article in SSAB Feb 1996 which discussed the possible correlation between major earthquake activity in Mexicalli Valley and fluid withdrawl from the geothermal field. Good reading! By golly, there is a geothermal power plant not far from the current swarm at Long Valley caldera! (and the light went on....) -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Seismometer construction link Date: Mon, 1 Dec 1997 14:23:46 -0600 Found this web site while browsing. It has some useful info and an interesting preamp schematic. http://www.info2000.net/~aloomis/seismom.htm Jim Hannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: fmurray@......... (frank murray) Subject: Re: Mammoth M4.8 Quake Date: Mon, 01 Dec 1997 20:59:16 GMT On Mon, 1 Dec 97 18:31:06 +0000, charles watson wrote: >.......... Call them and have your VISA/MC card ready. > >........The 40 M3's status change was obtained during a discussion with=20 >some ofthe seismologists at the USGS during the preceeding few weeks.=20 hmmm....if i read you right here, you are saying that buying a copy of the plan will not give me the precise criteria upon which the decision to go to "yellow" would be made...that, instead, the criteria are still, to some extent, in flux...is that what you are saying??...=20 >...........................They felt >that a if a significant swarm were to develop and it contained 40 or >more M3's, they would recommend to the CA OES a Volcanic Alert Status >change. this seems at variance with what the usgs says at: http://geopubs.wr.usgs.gov/FactSheets/RestlessCaldera/RestlessCaldera.htm= l where the indication is that the usgs will make the decision about a yellow watch and "notify" the oes of that decision...are you telling me that the decision, itself, will be made by oes rather than usgs??... >By the way, although a M4.8 quake did shake the region over the weekend, >there was no hazard to the thousands of people visiting the area. There >was no need to unjustly alarm people by prematurely issuing a YELLOW >alert...as you called for earlier.=20 hmmm...must be age...i remember making no such call...perhaps you'd provide me with the knowledge of where you have found my having done so...should you find that i've made no such call, use your new found realization as this week's treatment towards the cure of BIKS (Believing I Know Syndrome)...as the medication is potent, only a weekly dose is required... >Relax, relax..PVESD (Pre-Volcanic Eruption Stress Disorder) is curable >given knowledge twice daily. Caution: Knowledge is habit forming. :> yes...thank you...i'll use the forthcoming answers to my above questions for my daily dose... in medical wait, frank fmurray@......... for my electronic college proposal see: http://home.att.net/~fjtmurray/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Dave A. Nelson" Subject: seismometers Date: Tue, 02 Dec 1997 09:25:27 +1200 hi there, I don't know your first name as you don't have it anywhere on your pages. Another Excellent system available for digital recording can be found at Larry Cochrane's home pages at http://psn.quake.net although a wee bit dearer than some you mention on your pages the dos based data logging and windos based analysis software are very well written and FREE. There is now a large number of us guys around the world using this system which means instant compatability for conparing data files of events from around the world you may be unaware of this site and the wourld wide Public Seismic Network that has sprung up over the last few years see also Larry's pages for e-mail reflectors to join where MANY amateur seismo's are discussing events and equip. on my pages at (Larry hosts them) http://psn.quake.net/dave/quakes.htm you will find links to American, World, European New Zealand maps showing the locations of known amateur stations and also a database on those stations with info on their recording systems cheers Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Andy Loomis Subject: Re: seismometers Date: Mon, 1 Dec 1997 15:02:36 -0700 (MST) Hi Dave, First, thank you very much for the information on the PSN website. No, I wasn't aware it existed, and I am most pleased to offer a link to it on my webpage. The information I have on the seismometers we made at the University of Northern Colorado appears on two different websites. From the content of the letter you wrote to me, I suspect you saw the one that appears on the pages of the University of Northern Colorado's Earth Sciences Department. Unfortunately, that website is not as carefully updated as the one I maintain on my own. Further, it is not directly accessable to me -- involving a cumbersome process -- so I have pretty much abandoned any continuing involvement in it. May I direct your attention to my OWN website: http://www.info2000.net/~aloomis/seismom.htm THIS page is updated constantly. I think you'll find the information much more useful than on the UNC site. I have already added the link to the PSN site. You folks are doing some NICE stuff! If I can explain anything further, or be of any help at all, please let me know again. Sincerely, Andy Loomis, E-mail: aloomis@............ Ham Packet: KE0UL @ KE0UL.#NECO.CO.USA.NOAM _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Mammoth M4.8 Quake Date: Mon, 1 Dec 1997 14:02:41 -0800 (PST) Hello Charles: Yes, I've been a little on the edge since the latest swarm(s) occurred. And Hopefully it won't turn into another 1902 Mt. Pele for the USGS's sake! If Mammoth was just a normal volcano I wouldn't be as worried. But, with its past history of being gaseous, I kind of keep an eye and ear open for signs of any increased activity. Cause there's no telling how much of a warning the darn thing will give us when it does blow! Frank Condon mail to:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" >Frank- > >As you have probably seen... > >http://quake.wr.usgs.gov/VOLCANOES/LongValley/Response.html > >Response of the U.S. Geological Survey to episodes of unrest and the >onset of possible volcanic activity in the vicinity of Long Valley >caldera is described in Response Plans for Volcanic Hazards in the Long >Valley Caldera and Mono Craters Area, California: U.S. Geo. Survey Open >File Report 91-270, 64 p., 1991. Call them and have your VISA/MC card >ready. > >The 40 M3's status change was obtained during a discussion with some of >the seismologists at the USGS during the preceeding few weeks. They felt >that a if a significant swarm were to develop and it contained 40 or >more M3's, they would recommend to the CA OES a Volcanic Alert Status >change. > >Obviously, the caldera has NOT reach this level of activity as of yet >and does not warrant a status change. As they have said to me, this is a >learning opperation, and they (the USGS and the CA OES) welcome comments >from qualified members of the community. > >By the way, although a M4.8 quake did shake the region over the weekend, >there was no hazard to the thousands of people visiting the area. There >was no need to unjustly alarm people by prematurely issuing a YELLOW >alert...as you called for earlier. They had a fine time and experienced >a little bit of Mammoth take home with them and tell stories about to >their relatives who stayed away in fear that the mountain was going to >blow. > >Relax, relax..PVESD (Pre-Volcanic Eruption Stress Disorder) is curable >given knowledge twice daily. Caution: Knowledge is habit forming. :> > >-- >---/---- >Charlie > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Seismometer construction link Date: Tue, 02 Dec 1997 10:07:59 +1200 Thanks Jim, I e-mailed the guy informing him of the PSN etc. A copy was Cc'ed to the PSN mailer under ther subject Seismometers speaking of Cc 'ing mail what does Bcc do my email prog has that one too Dave At 02:23 PM 12/1/97 -0600, you wrote: >Found this web site while browsing. It has some useful info and an >interesting preamp schematic. >http://www.info2000.net/~aloomis/seismom.htm Jim Hannon Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Response from Andy Loomis Date: Tue, 02 Dec 1997 10:14:49 +1200 NOTE: his own home page as stated below is better updated than the one Jim and I initially visited Hi Dave, First, thank you very much for the information on the PSN website. No, I wasn't aware it existed, and I am most pleased to offer a link to it on my webpage. The information I have on the seismometers we made at the University of Northern Colorado appears on two different websites. From the content of the letter you wrote to me, I suspect you saw the one that appears on the pages of the University of Northern Colorado's Earth Sciences Department. Unfortunately, that website is not as carefully updated as the one I maintain on my own. Further, it is not directly accessable to me -- involving a cumbersome process -- so I have pretty much abandoned any continuing involvement in it. May I direct your attention to my OWN website: http://www.info2000.net/~aloomis/seismom.htm THIS page is updated constantly. I think you'll find the information much more useful than on the UNC site. I have already added the link to the PSN site. You folks are doing some NICE stuff! If I can explain anything further, or be of any help at all, please let me know again. Sincerely, Andy Loomis, E-mail: aloomis@............ Ham Packet: KE0UL @ KE0UL.#NECO.CO.USA.NOAM Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Mexicali 3.6M Earthquake Date: Mon, 1 Dec 1997 14:13:42 -0800 (PST) Hello Charles: Well, if that isn't just a coincidence that both areas are being mined for their geothermal resources and just happen to be swarming with quakes, too! An interesting observation on your part. What about the area around Ridgecrest (Little Lakes)? Isn't that another site that has been used to extract geothermal energy from the Earth? Frank Condon mail to:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" >Frank Condon wrote: >> >> Hello all: >> Could someone please tell me how far away was the recent 3.6M earthquake in >> Mexico from the >> Quarternary "Cerro Prieto" Volcano? Also, speculate "If Mammoth were to go >> active, then what are the chances that it would be the next one in the chain >> to become restless? >> >> 3.6 97/11/28 06:51:38 32.36N 115.31W 6.0 23 mi SSE of MEXICALI >> > >The quake occurred pretty darn close to the Cerro Prieto volcano. The >Mexican Government has allowed the development of a major geothermal >power plant in the area to tap the thermal resource for producing >electricity for their country and to sell to the Americans across the >border. > >Seismicity is common in the area and has been the site of some >significant swarms in the past. This past summer there was a robust >swarm which consisted of a couple thousand of events over the course >6-weeks, including a dozen or so in the M3 range. The largest was M3.6, >I think. Rarely, does activity get in the M4 range and less common above >that. There was an article in SSAB Feb 1996 which discussed the possible >correlation between major earthquake activity in Mexicalli Valley and >fluid withdrawl from the geothermal field. Good reading! > >By golly, there is a geothermal power plant not far from the current >swarm at Long Valley caldera! (and the light went on....) > >-- >---/---- >Charles P. Watson, Consulting Geologist >Advanced Geologic Exploration >Seismo-Watch / Earthquake Information Services >Voice: 702-852-0992 / Fax: 702-852-3226 >Office Location: 39.43N 119.71W >mailto:watson@................ >http://www.seismo-watch.com > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: Seismometer construction link Date: Mon, 01 Dec 1997 17:04:51 -0600 David A. Nelson wrote: > > speaking of Cc 'ing mail what does Bcc do my email prog has that one too > > Dave > > The Mail Bcc field contains the email address where you want a blind copy of your message sent. A blind copy does not display the address of the copy recipient -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Event late on the 26th Date: Mon, 01 Dec 1997 16:26:29 -0700 (MST) Hello Everyone, I received an odd event late on the 26th (Mountain Time Zone), but none of the earthquake lists will display events earlier than late on the 27th. Anybody know where such a list could be found????????? ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert Avakian Subject: Re: Mexicali 3.6M Earthquake Date: Mon, 01 Dec 1997 19:36:31 -0800 BAck in the late 60's a small swarm of quakes around Denver's Rocky Mt. Arsenal was triggered by pumping fluid into the ground, but theory would suggest that removal of fluids should actually keep quakes from happening, not start them. Avakian Charles Watson wrote: > > Frank Condon wrote: > > > > Hello all: > > Could someone please tell me how far away was the recent 3.6M earthquake in > > Mexico from the > > Quarternary "Cerro Prieto" Volcano? Also, speculate "If Mammoth were to go > > active, then what are the chances that it would be the next one in the chain > > to become restless? > > > > 3.6 97/11/28 06:51:38 32.36N 115.31W 6.0 23 mi SSE of MEXICALI > > > > The quake occurred pretty darn close to the Cerro Prieto volcano. The > Mexican Government has allowed the development of a major geothermal > power plant in the area to tap the thermal resource for producing > electricity for their country and to sell to the Americans across the > border. > > Seismicity is common in the area and has been the site of some > significant swarms in the past. This past summer there was a robust > swarm which consisted of a couple thousand of events over the course > 6-weeks, including a dozen or so in the M3 range. The largest was M3.6, > I think. Rarely, does activity get in the M4 range and less common above > that. There was an article in SSAB Feb 1996 which discussed the possible > correlation between major earthquake activity in Mexicalli Valley and > fluid withdrawl from the geothermal field. Good reading! > > By golly, there is a geothermal power plant not far from the current > swarm at Long Valley caldera! (and the light went on....) > > -- > ---/---- > Charles P. Watson, Consulting Geologist > Advanced Geologic Exploration > Seismo-Watch / Earthquake Information Services > Voice: 702-852-0992 / Fax: 702-852-3226 > Office Location: 39.43N 119.71W > mailto:watson@................ > http://www.seismo-watch.com > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Re: Minimum sampling rate. Date: Mon, 1 Dec 1997 21:43:39 -0500 Norman, For 'quakes where maximizing the signal to noise ratio is critical, an upper frequency limit should be around 0.1Hz. This helps avoid the noise peak near 0.16Hz. Since you are in CA you should get local (say within 200 mi.) 'quakes. = Hi-fidelity records of these require a much higher freq. response, say up= to 10 or 20 Hz. People often use two channels recording the same signal with one with filtered to the 0.1Hz limit and the other with the 10-20Hz. limit. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: Force of Lehman susp. wire Date: Mon, 01 Dec 1997 22:02:53 -0800 On 11/22/97 Robert L Barns wrote: .... > A frictionless pivot for the end of the boom is the "Zollner' suspension > which is described in Aki & Richards, "Quantitative Seismology", vol. 1, > 1980, p 484. ... Bob, Was the description that followed the above sentence a description of the Zollner pivot, or another pivot of your own design that you are using? Thanks, Charles R. Patton, Editor, Geo-Monitor home: 909-698-9657 work 714-932-7476 fax:909-698-0224 email: patton@......... Geo-Monitor homepage: http://iinet.com/users/patton _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Mexicali 3.6M Earthquake Date: Tue, 02 Dec 1997 00:01:57 -0700 Frank Condon wrote: > > > Well, if that isn't just a coincidence that both areas are being mined for their > geothermal resources and just happen to be swarming with quakes, too! An > interesting observation on your part. What about the area around Ridgecrest > (Little Lakes)? Isn't that another site that has been used to extract > geothermal energy from the Earth? > Humm..title the report: "Elevated seismicity at three western US KGRAs during 1997" KGRA = Known Geothermal Resource Area -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: [Fwd: PSN theme song] Date: Tue, 02 Dec 1997 01:30:01 -0700 -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". I think I sent this to you once before, but just ran across it in my browsing: Now we all move, we're moving with this Earth. The Earth is moving along, the water is moving along The grass is moving, the trees are moving the whole Earth is moving. So we all move along with the Earth, keeping time with the Earth. a Potawatomi song, quoted in essay by Joan Halifax in Dharma Gaia From: Sam Toon Subject: Re: Mexicali 3.6M Earthquake Date: Tue, 2 Dec 1997 12:26:17 -0500 (EST) On Mon, 01 Dec 1997 19:36:31 -0800 Robert Avakian wrote: > BAck in the late 60's a small swarm of quakes around Denver's Rocky Mt. > Arsenal was triggered by pumping fluid into the ground, but theory would > suggest that removal of fluids should actually keep quakes from > happening, not start them. > Yes, but to obtain geothermal power plants work by pumping water into the ground down one well and returns to the surface up another well. See this site http://www.ees4.lanl.gov/HOTDRYROCK.HTML for a good description of the concept. Sam ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Sam Toon serr15@......... Microseismology Research Group http://www.liv.ac.uk/~serr15/Microseis/ Dept of Earth Sciences Tel: +44 (0)151 794 5157 University of Liverpool Fax: +44 (0)151 794 5157 P.O. Box 147, Liverpool, L69 3BX United Kingdom ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Mike Stickney Subject: Re: Mexicali 3.6M Earthquake Date: Tue, 2 Dec 97 08:11:56 MST Avakian: Not so! Fluid extraction has also been shown to trigger seismicity in at least one southern California oil field. I can't remember the reference off the top of my head but could probably find it if you're interested. -Mike Stickney Montana Bureau of Mines and Geology ============================================ At 07:36 PM 12/1/97 -0800, you wrote: >BAck in the late 60's a small swarm of quakes around Denver's Rocky Mt. >Arsenal was triggered by pumping fluid into the ground, but theory would >suggest that removal of fluids should actually keep quakes from >happening, not start them. > >Avakian _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Marnie Gannon Subject: Induced Earthquake Bibliography Date: Tue, 02 Dec 1997 08:47:59 -0700 You're All correct! Here's a good reference. URL is at bottom of page. Marnie > [ ] Induced Earthquake Bibliography [ ] > > "Civilization exists by geological consent, subject to change without > notice." William Durant > > This bibliography is contains references to publications concerning > earthquakes and other seismicity induced by human activity. > > Additions are welcome! To add a citation click here > > Warning to non-scientists > > Topics: [ ] > * Induced Earthquakes in General (6 references) > * Injection Induced Earthquakes (116 references) > o Rocky Mountain Arsenal quakes > * Reservoir Induced Earthquakes (127 references) > * Oil & Gas Production Induced Earthquakes (48 references) > * Geothermal Energy Extraction Induced Earthquakes (38 references) > * Mining and Quarrying Induced Earthquakes (89 references) > * Nuclear Test Induced Earthquakes (20 references) > * Seismicity Related to Underground Gas Storage (7 references) > * Legal Implications of Induced Earthquakes (13 references) > * Miscellaneous References (21 references) > * Newspaper & Magazine References > * Links to other induced seismicity webpages > > ---------------------------------------------------------------------- > > CITATION FORM > > WANTED: > > 1. URLS related to induced seismicity > 2. Photographs related to induced seismicity. > > Authors: If you would like your name in the citations linked to your > homepage, e-mail your URL to me. > > ---------------------------------------------------------------------- > > This bibliography is maintained by Darlene A. Cypser. Please send > e-mail to me at dcypser@....... if you have any questions or comments, > or would like to make any additions or corrections to this > bibliography, or visit my homepage. > > ---------------------------------------------------------------------- > > This page comes to you courtesy of Nyx a public access Internet > service. > ---------------------------------------------------------------------- > [Stats] > > Last update: 8/27/97 http://www.nyx.net/~dcypser/induceq/induceq.bib.html _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Dewayne Hill Subject: UPPER SUPPORT POINT Date: Tue, 02 Dec 1997 08:47:37 -0700 I am in the final stages of assembling my seismometer, but I have been put in a state of quandary by some of the information posted here verses information at the PSN web site. In Karl Cunninghams post on 11/23/97 @ 22:59 he said that the upper support point should be behind the lower support point. Yet in the SAS article from 1979 it states that the upper support should be 1 cm. forward of the lower support point. I my way of thinking. The weight (mass) end would be the forward end with the vertical support being the back end. Can someone clarify this for me before I get any further in my assembly. Dewayne Hill n0ssy@................ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Induced Earthquake Bibliography Date: Tue, 02 Dec 1997 09:33:07 -0700 That's a good induced seismicity bibliography. Actually talked to Darlene at one time. She works on it for a hobby, practicing at law for an occupation. She was originally concerned about the induced seismicity at Rocky Mountain Flats and, being a trained lawyer adept at research, it expanded from there. Great service! -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: UPPER SUPPORT POINT Date: Tue, 02 Dec 1997 10:23:03 -0800 Dewayne -- When finally adjusted, the position of the upper and lower pivots will be so close it is hard to tell which is ahead, and very fine adjustment is necessary to achieve long natural periods. A popular method to make this adjustment is to use screws to adjust the level of the base, since the relative position of the two pivots is really measured with respect to the direction of the gravity vector. In my post of 11/23, I was suggesting that were it not for the influence of the restoring force of the suspension wire, the upper pivot would be in front of the bottom one. However, to make up for this spring force, the final adjustment of a long-period Lehman may result in the top pivot actually being behind the bottom one. Not by very much -- probably much less than 1mm. -- Karl At 08:47 AM 12/2/97 -0700, you wrote: >I am in the final stages of assembling my seismometer, but I have been >put in a state of quandary by some of the information posted here >verses information at the PSN web site. > >In Karl Cunninghams post on 11/23/97 @ 22:59 he said that the upper >support point should be behind the lower support point. Yet in the >SAS article from 1979 it states that the upper support should be >1 cm. forward of the lower support point. I my way of thinking. The >weight (mass) end would be the forward end with the vertical support >being the back end. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: UPPER SUPPORT POINT Date: Tue, 2 Dec 1997 12:46:57 -0600 Practically it is best to design the instrument so that the pivot points are in a vertical line. The leveling screws are then used to make the fine adjustments of the alignment necessary to adjust the period and centering. If there is no spring effect from the support wire the upper pivot will end up slightly forward of the lower pivot after adjustment. Jim Hannon n0ssy@................ on 12/02/97 09:47:37 AM Please respond to psn-l@............. To: PSN-L@............. cc: (bcc: James M Hannon/CedarRapids/Collins/Rockwell) Subject: UPPER SUPPORT POINT I am in the final stages of assembling my seismometer, but I have been put in a state of quandary by some of the information posted here verses information at the PSN web site. In Karl Cunninghams post on 11/23/97 @ 22:59 he said that the upper support point should be behind the lower support point. Yet in the SAS article from 1979 it states that the upper support should be 1 cm. forward of the lower support point. I my way of thinking. The weight (mass) end would be the forward end with the vertical support being the back end. Can someone clarify this for me before I get any further in my assembly. Dewayne Hill n0ssy@................ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Doug Crice Subject: Re: Mexicali 3.6M Earthquake Date: Tue, 02 Dec 1997 11:08:29 -0800 I was at the SSA meeting in Golden when they gave a paper on the Denver Earthquakes/Rocky Mountain Arsenal. At the time, the scientific community completely rejected the idea that you could create earthquakes by fluid injection. It was pretty easy to show with mathmatics and common sense that it was impossible. The issue was stirred up by a local newspaper that correlated the injections (of fluids from the Denver Arsenal into a deep disposal well) with earthquake swarms (we're talking good sized earthquakes here, enough to shake people up) and published the charts on the front page of the paper. The establishment poo-pooed the idea, but there was enough publicity that finally they had to do some serious research to stifle the debate. They set up arrays of seismometers, did their research, and found out surprisingly that the earthquakes were coming from the bottom of this deep well (used to dispose of by-products of nerve gas production back when it was politically correct to just stick noxious juices in the ground) and there was some correlation with pumping. They reported the results at the SSA meeting, and ended with your choice of titles: "The enema theory of earthquakes" or "Denver gets it in the Arsenal". Doug Crice _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Re: Force of Lehman susp. wire Date: Tue, 2 Dec 1997 14:29:13 -0500 Charles, I did not describe the Zollner. The description was something I though= t would work but I haven't tried it. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: Force of Lehman susp. wire Date: Tue, 02 Dec 1997 12:13:07 -0800 Bob, Sorry about this, I should have asked in the last post--can you please do a brief description of the Zollner pivot? Thanks, Charles R. Patton patton@......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Raster USGS topo maps? Date: Tue, 02 Dec 1997 12:26:19 -0700 I am looking for USGS topographic maps that have been raster formated (ie; tiff, jpg, giff, tga, etc.). Any one know where I could find some? web or corporate? -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: Raster USGS topo maps? Date: Wed, 3 Dec 1997 07:56:09 -0600 This site has street maps not topo maps but it might be useful to someone. http://tiger.census.gov/ JIm Hannon watson@................ on 12/02/97 01:26:19 PM Please respond to psn-l@............. To: psn-l@.............. QUAKE-L@................... Research@.................. in@.................. Quaternary@.................. Science@.................. QUATERNARY@.................. eq-geo-net@.................. cc: (bcc: James M Hannon/CedarRapids/Collins/Rockwell) Subject: Raster USGS topo maps? I am looking for USGS topographic maps that have been raster formated (ie; tiff, jpg, giff, tga, etc.). Any one know where I could find some? web or corporate? -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Mark Wilson mark@.............." Subject: Re: Raster USGS topo maps? Date: Wed, 3 Dec 1997 08:42:56 -0800 (PST) On Tue, 2 Dec 1997, Charles Watson wrote: > I am looking for USGS topographic maps that have been raster formated > (ie; tiff, jpg, giff, tga, etc.). > > Any one know where I could find some? web or corporate? Try ESRI at http://www.esri.com I am currently trying to get this type of mapping into Caligari Truespace 3 for modeling. I was talking to a Robert Flores, I don't know if that is what you want, but give it a try 909.793.2853 ext 1-1830 If this does not work, I would be interested in where. However, I always assumed that raster graphics were not bitmapped like gif, tga etc.. Postscript or DXF I alway thought was raster/vector. Don't you want XYZ coordinate stuff? *********************************************************************** --- mark@.............. --- http://www.markwilson.com --- wilsonm@............ *********************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Walt Williams" Subject: Advice: GraviMeter Date: Wed, 3 Dec 1997 09:57:16 +0000 Hello, Occasionally I see posts from people who are well familiar with magnetometers and similar type instruments. My SG is nearly complete and when finished I will place pictures of the instrument on my web site. I desire to build a gravimeter if such is feasible. One instrument I have read about uses a beam which is suspended with a spring. Gravity apparently deflects the beam. A mirror is attached on the 'swing' end of the boom. LASER energy is reflected from the mirror into an optical sensor which is used as the readout of the instrument. I suspect instrument accuracy is greatly affected by temperature of the spring. Any ideas, groups or identities of people who are constructing gravity measuring devices and/or recommendations of reference material will be appreciated. Thanks in advance. Walt Williams, 97.12.03 dfheli@.............. http://www.pacificnet.net/~dfheli _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Mike Stickney Subject: Date: Wed, 3 Dec 97 11:00:17 MST Hello all: I just wanted to point out new epicenter maps for the U.S. and World, available on the Web at the URL below. The Council of the National Seismic System (CNSS) compiled these maps and maintains a U.S. map of recent quakes with magnitudes down to 2.0. Enjoy. http://quake.geo.berkeley.edu/cnss/maps/cnss-map.html -Mike Stickney Montana Bureau of Mines and Geology Butte, MT _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: UPPER SUPPORT POINT Date: Wed, 03 Dec 1997 18:34:26 +0000 Hi Dewayne, You may like to see my posting about this on 28 Oct. ( 'formula for hor. pendulums). Providing top suspension is VERY flexible, top suspension is always slightly in front of bottom pivot.....this gives beam its central stability. My form. shows relationship between this slight offset, the beam length, and the period of beam. Hope this helps. Regards, Albert Noble (England). Dewayne Hill wrote: ....................... > weight (mass) end would be the forward end with the vertical support > being the back end. > > Can someone clarify this for me before I get any further in my > assembly........................ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Randle Olsen Subject: Raster USGS Topo Maps - Reply Date: Wed, 03 Dec 1997 13:49:58 -0500 Your request to Elly Brouwers was forwarded to me. Requested info can be found on webpage HTTP://MCMCWEB.ER.USGS.GOV/DRG/. For other mapping coverages, our mapping homepage has a number of hot links to available data - HTTP://MAPPING.USGS.GOV _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roger Baker Subject: Re: Advice: GraviMeter Date: Wed, 03 Dec 1997 14:19:38 -0600 Walt, I've been around that track a few times and here is what I have learned, some of which I posted before, but I keep learning more. I doubt that anybody has ever built a sensitive gravimeter that wasn't temperature controlled, with the possible partial exception of the Worden gravimeter which was built entirely of tiny quartz fibers in an ingenious configuration inside a thermos bottle and then read out with a microscope. Otherwise building a gravimeter capable of seeing earth tides is a matter of either building a sensitive magnetic or spring suspension and detecting nanometers of motion on a horizontal beam. A company here in Austin still builds miniature gravimeters based on the zero length spring suspension originally invented for vertical motion seismometers by La Coste in the 1930's. When you have a mirror/magnet dangling on the end of a vertical filament, like for a torsion magnetometer, a simple laser pointer and phototransistor makes a nice way to detect minute rotations and you should be able to see a constant background level of micropulsations this way. This arrangement tends to drift so its best to create a force feedback field with Helmholtz coils to keep the laser beam centered on the phototransistor, which can be mounted immediately behind a piece of half covered frosted glass to tell the circuit which way to correct the magnetic field to keep the laser beam centered. Shifting gears to gravimeters, where you have a horizontal beam, a superbright red LED and a phototransistor with their plasic lenses sawed off repolished and mounted in close proximity facing each other makes a very sensitive motion detector. Arrange them so that their bottom half is masked off up to the sensitive spots and then the beam carries a little aluminum flag that bobs up and down to totally block the beam. You may object that these sensors are temperture sensitive, but they are enclosed in the same rather small temperature controlled enclosure as the beam. A simple thermistor feedback circuit may be used to control temperature to within a hundredth or maybe a few thousanths of a degree in only one stage. My way to get good control is to glue many equally spaced small resistors to the aluminum enclosure with silicone and make them of such a value that the enclosure will only gradually heat up to five or ten degrees above ambient when the aluminum box is completely and snugly encased in styrofoam. The thermistor should be glued directly to one of these heating elements, and a high gain op amp circuit used to control a power darlington in series with the resistors in a parallel array. The best arrangement I have found is to have the heating circuit pulse on and off at intervals of a second or so. This uses far less power than having the heater half way on all the time. Put a capacitor across the feedback resistor in the final op amp gain stage just before the darligton to slow down the turn on and turn off transition a little and make it gentle or it will screw up any sensitive electronics operating off the same power supply. Even so, this circuit tends to create a slight voltage shift as it cycles on and off. Everything considered, this temperature control method only takes a few watts of power, is easily built with simple Radio Shack type parts, and is probably appropriate to many small sensitive scientific instruments with dimensions of a few inches. Every sensitive instrument is also a thermometer, like it or not. --Yours, Roger Baker At 09:57 AM 12/3/97 +0000, you wrote: >Hello, > >Occasionally I see posts from people who are well familiar with >magnetometers and similar type instruments. My SG is nearly complete >and when finished I will place pictures of the instrument on my web >site. I desire to build a gravimeter if such is feasible. One >instrument I have read about uses a beam which is suspended with a >spring. Gravity apparently deflects the beam. A mirror is attached on >the 'swing' end of the boom. LASER energy is reflected from the >mirror into an optical sensor which is used as the readout of the >instrument. I suspect instrument accuracy is greatly affected by >temperature of the spring. Any ideas, groups or identities of people >who are constructing gravity measuring devices and/or recommendations >of reference material will be appreciated. > >Thanks in advance. > >Walt Williams, 97.12.03 >dfheli@.............. >http://www.pacificnet.net/~dfheli > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Doug Crice Subject: Re: Advice: GraviMeter Date: Wed, 03 Dec 1997 12:21:54 -0800 The definitive paper on building gravimeters was written by Lucien LaCoste about 50 years ago, and it was reprinted in the Leading Edge magazine of the Society of Exploration Geophysics just a few years ago. So, go to the SEG site http://www.seg.org/ and search their data base for the reference for that paper, then go to your local university library and copy the article. The physics of a gravimiter is not much different from a vertical Lehman supported by a "zero-length" spring. A zero length spring is one that follows the equation F = kx where when F = 0, the length of the spring would be zero. The paper tells you how to wind the spring. Of course the wire is very special stuff in terms of long-term stability and temperture coefficient. LaCoste and Romberg Gravimiters are still made with wire springs in Austin Texas. Wusses who want to take the easy way out use quartz springs. Scintrex makes a popular gravimiter with quartz springs and automatic adjustments. Sam Worden also make quartz gravimiters. So cruise around the web using LaCoste and Romberg as one search term and Scintrex as another and Worden for good luck and you will find some information. Interestingly enough, that special wire works better than quartz. Too bad you can't buy it. Making a gravimiter is not too different from making a spring scale with a stability of 1 part in 10-8. Doug Crice _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: [Fwd: Re: AGU Press Releases] Date: Wed, 03 Dec 1997 14:06:29 -0700 -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". "You don't need to be a weatherman to know which way the wind blows" Bob Dylan How dangerous is Mammoth Lakes? Do we know? With what certainty can both false alarms be avoided and adequate warnings provided? The Mammoth Lakes seismic events of the last few weeks have shown the coming of age of the Public Seismic Network (PSN) as a vigorously functioning, Web-based amateur seismological community. The PSN is a rapidly growing international group of amateur seismologists, concentrated in California, who record earthquakes with their own digital seismographs and exchange waveform time series and communicate with each other via the Internet. With PSN members near and actually in the Mammoth Lakes zone, the organization uniquely links scientific and public domains. In the past the USGS has been skeptical as to how large a contribution the PSN could make. Now, as we see the USGS and the California Office of Emergency Services navigating the narrow channel between over and under the increased seismicity at Mammoth Lakes, we find in the PSN a lively forum that combines scientific data gathering and the freedoms and imperatives of private citizens. Seldom does the Earth telegraph its intentions unambiguously to the scientific community. There is almost always great room for debate, particularly with respect to the timing of infrequent, catastrophic events. Given this situation, distribution of the raw data along with a range of possible interpretations to as many well informed citizens as possible compliments the more formal and regimented color code system for conveying hazard information. AN: U51A-05 LO: MC HALL D HR: 0830h DA: Friday TI: Public Seismic Network (PSN): A Model for Preparing People to Use Real-Time Information About Natural Hazards AU: *E Cranswick, B Gardner MN: Fall Meeting 1997 Heidi Koehler wrote: > > Hi Don & Ed, > > Apologies for not shooting this off to you earlier-- > > Please email me a basic who, what, when (day, time), where (room#) & why > the public should care about the presentations you (or your co-authors) > will be giving @ AGU by 12 p.m. December 3. With this information, I'll be > able to build a general press release (and individual releases if you'd > like) and begin to get the attention of the media. > > Let me know if you have any questions--hope you had fabulous turkey days! > > : ) > Heidi > > *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-* > Heidi Koehler > Outreach Assistant > U.S. Geological Survey > Central Region, Regional Director's Office > P.O. Box 25046, MS 150 > Denver, CO 80225 > Phone: (303)236-5900 x302 > Fax: (303)236-5882 > email: hkoehler@........ > *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-* -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". From: watson@................ (Charles Watson) Subject: Re: Date: Wed, 03 Dec 1997 13:12:56 -0700 Mike Stickney wrote: > > Hello all: > I just wanted to point out new epicenter maps for the U.S. and > World, available on the Web at the URL below. The Council of the National > Seismic System (CNSS) compiled these maps and maintains a U.S. map of recent > quakes with magnitudes down to 2.0. Enjoy. > > http://quake.geo.berkeley.edu/cnss/maps/cnss-map.html > Mike, Gleefully, I looked at the M7.8+ events for 1946-1996 at the above URL and notice the Great Chile earthquake in 1960 was missing. Do you know what catalog they used? Maybe the magnitude was downgraded, eh? http://quake.geo.berkeley.edu/cnss/maps/eqs/world_2_01.01.1946-12.31.1996_M-7.8.gif -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: Advice: GraviMeter Date: Wed, 3 Dec 1997 15:51:42 -0600 Since time or frequency is one of the things that can be most accurately measured, couldn't one build a gravimeter that actually measured the acceleration of gravity on a free falling object in a vacuum say using a laser interferometer? It sticks in my mind that I read about such a device developed by the NBS some years ago. Jim Hannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Raster USGS topo maps? Date: Wed, 03 Dec 1997 14:53:24 -0700 Thanks for the url! -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Re: Minimum sampling rate. Date: Tue, 02 Dec 1997 20:15:46 At 09:43 PM 12/1/97 -0500, you wrote: >Norman, > For 'quakes where maximizing the signal to noise ratio is >critical, an upper frequency limit should be around 0.1Hz. This helps >avoid the noise peak near 0.16Hz. > Since you are in CA you should get local (say within 200 mi.) 'quakes. >Hi-fidelity records of these require a much higher freq. response, say up >to 10 or 20 Hz. > People often use two channels recording the same signal with one with >filtered to the 0.1Hz limit and the other with the 10-20Hz. limit. >Bob Barns That clears it up for me. I have a lowpass 20hz under constuction. That should do for starters. Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Doug Crice Subject: Re: [Fwd: Re: AGU Press Releases] Date: Wed, 03 Dec 1997 15:56:40 -0800 That press release is rather well written. I like to fancy myself as a wordsmith, but not in this league. Doug _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: James Subject: Question from an interested lurker Date: Wed, 3 Dec 1997 19:04:59 -0600 (CST) I've been watching this list for over a year now. I've learned alot about earthquakes. Thanks to all of you. I hope to build my own Lehman during the next year. I have a question: How is it possible to determine the distance and direction of an earthquake from 1 location? Thanks _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: [Fwd: press release!!!] Date: Wed, 03 Dec 1997 18:48:27 -0700 -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". science for a changing world News Release U.S. Department of the Interior Office of Outreach U.S. Geological Survey Central Region PO Box 25046, MS 150 Denver, CO 80225-0046 Release Contact Phone Email December 3, 1997 Heidi Koehler 303.236.5900x302 hkoehler@........ PUBLIC SEISMIC NETWORK LURES HAZARD-PRONE COMMUNITIES INTO SCIENCE "You don't need to be a weatherman to know which way the wind blows" Bob Dylan How dangerous is Mammoth Lakes? Do we know? With what certainty can both false alarms be avoided and adequate warnings provided? The Mammoth Lakes seismic events of the last few weeks have shown the coming of age of the Public Seismic Network (PSN) as a vigorously functioning, Web-based community created by amateur seismologists. Edward Cranswick, a geophysicist with the U.S. Geological Survey in Golden, Colo. will illustrate the value of PSN at a poster session entitled, "Public Seismic Network (PSN): A Model for Preparing People to Use Real-Time Information About Natural Hazards" on Friday, December 12 at 8:30 a.m. at the Fall 1997 meeting of American Geophysical Union in San Fransisco, Room U51A-05, MC HALL D. During the session, Cranswick and Larry Cochrane, PSN, Redwood City, Calif., will demonstrate a PSN seismograph and the PSN website, http://psn.quake.net . "Seldom does the Earth telegraph its intentions unambiguously to the scientific community. There is almost always great room for debate, particularly with respect to the timing of infrequent, catastrophic events," said John Lahr, a USGS geophysicist. "Given this situation, distribution of the raw data along with a range of possible interpretations to as many well-informed citizens as possible compliments the more formal and regimented color code system for conveying hazard information." (I MOVED THIS UP B/C JOURNALISTS ARE HUNGRY FOR QUOTES UP HIGH...) 2-2-2 PSN The PSN is a rapidly growing international group of amateur seismologists, concentrated in California, who record earthquakes with their own digital seismographs and exchange waveform time series and communicate with each other via the Internet. With PSN members living near and actually in the Mammoth Lakes zone, the organization uniquely links scientific and public domains. ***USGS*** From: Ted Blank Subject: Re: Question from an interested lurker Date: Wed, 3 Dec 1997 19:00:11 -0800 (PST) You can determine distance from 1 record, and get an estimate of direction, but for most accuracy you would triangulate from multiple recordings. (They say that the estimates of direction come from noting whether first motions are up or down at your site, but I've never delved into this more deeply...would like to if I get the time (ha)). The simplest way for me to calculate distance is to use the fact that P waves travel faster than S waves. The farther apart (in time) they are when they reach your station, the farther away from you the source was. Perhaps someone more knowledgeable can let us in on the secrets of the up/down motions. > Ted Blank > I've been watching this list for over a year now. I've learned alot about > earthquakes. Thanks to all of you. > > > I hope to build my own Lehman during the next year. > > I have a question: > How is it possible to determine the distance and direction of an earthquake > from 1 location? > > > > Thanks > > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: Question from an interested lurker Date: Wed, 03 Dec 1997 20:52:56 -0700 James- To complement Ted Blank's reply explaining how to estimate distance, here is how one uses the first motions of P-waves to estimate direction. The method assumes that one has three components (Z=vertical, North-South, East-West) of motion. We know that all seismic (earthquake or explosion) sources are down in the Earth, so the **body waves** are always moving up towards us away from the source. If the first motion, i.e., the direction of the **ground motion** produced by first P-wave that arrives, on the Z-component is up, i.e., ___/\___ then we know the that the ground is moving away from the source. Hence, for example, if the motion of that same first P-wave is North on the NS component and East on the EW component -- which are the directions away from the source, then the source must be in the opposite direction, i.e., to the SouthWest. Conversely, if the first motion on the Z-component is down, i.e., ___ ___ \/ then we know that ground motion is towards the source. In that case, a first motion to the North and to the East would indicate that the source is to the NorthEast. If there is little amplitude on the NS component compared to the EW component, the source is more to the East or West rather than to the North or South. One can actually make quantitative measures of the first motions and perform a vector analysis to obtain more precise estimates of direction -- but this assumes accurate polarity and amplification information and that no strong site response exists -- that is usually somewhat problematic (even assuming one has clear records of the first P-wave with good signal to noise). But it's fun; try it! -Edward PS. Ironically I tried to analyze Mammoth Lakes aftershock data from the 1980 four M6+ earthquake sequence with the first program I wrote to do vector analysis of first motions. This exercise taught me how complicated the Earth is and how difficult it is to know and keep track of instrument response. James wrote: > > I've been watching this list for over a year now. I've learned alot about > earthquakes. Thanks to all of you. > > I hope to build my own Lehman during the next year. > > I have a question: > How is it possible to determine the distance and direction of an earthquake > from 1 location? > > Thanks > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Mammoth M4.8 Upgraded to a M4.9! Date: Wed, 3 Dec 1997 20:14:42 -0800 (PST) Hello All: The earthquake that occurred within the caldera last Sunday was upgraded to a M4.9 That really brings it very close to going into a YELLOW alert status! I heard an interview on the radio that was done with Dr. David Hill about the current condition of the caldera. This was aired on the Art Bell "Dreamland" Talk show. I think there will be another update about the current status of Mammoth Lakes this coming Sunday on his show. If interested see http://www.artbell.com/ for the latest schedule. Frank Condon mail to:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredithlamb@........ (meredith c lamb) Subject: Streckeisen seismometers Date: Wed, 3 Dec 1997 21:07:43 -0700 Hi group, Am interested in knowing of any WWW site hosting any information regarding Streckeisen seismometers. In particular the internal workings of them. Have seen alot of bell jars and non descriptive references of their leaf springs and feedback electronics. Am seeking amateur engineering adoptive aspects of their sensor mechanical/electrical "blue prints". Even the address of the company or a photo would help. Thanks. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: [Fwd: Re: AGU Press Releases] Date: Thu, 04 Dec 1997 10:13:16 -0700 Charlie- Thanks for your kind remarks. Ben Gardner, USGS volunteer for science who has been working with me on various PSN-related activities since 1991, wrote the original press release material about the PSN and Mammoth Lakes, and then we, the USGS, revised that into the "appropriate professional" form. That is a good idea about the two modes of presenting the data. I am glad you have your great record of the the Alabama event up there, because I can weave that into my rap about USGS/PSN cooperation since we, the USGS, went out to Atmore to chase that event. -Edward Charlie Rond wrote: > > Edward, > > >How dangerous is Mammoth Lakes? ... > > Very well done! I know your presentation will go well. > > If you do a demo at the meeting, you might note that on the PSN-Memphis Web > page I've posted several seismograms. You can click on the file name and > download the recording - just as on Larry's Redwood City page. But what I > have done differently is also post a "screen capture" of a WinQuake display > of each recording. This allows a person without the WinQuake software to > view and/or download that image, and it also allows a MAC user to view > and/or download and display the recording - something heretofore impossible > for them. > > I've also created a section to post St. Agnes Academy seismograms. They > have picked up several but we've not gotten them transferred yet, so they > may not be posted by AGU time. > > Take good care of yourself.. > > Charlie Rond -\/\--Public Seismic Network-Memphis > rond@................ (901) 360-0302 [ free BBS ] > http://gandlf.ceri.memphis.edu/~rond http://gandlf.ceri.memphis.edu/~rond/psn -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Walt Williams" Subject: Neural Nets for Seismic Data - Abstracts Date: Thu, 4 Dec 1997 14:48:24 +0000 Hello, Several weeks past I posted URL which pointed to a NASA server that apparently sporadically malfunctions or is very slow. I appologize for not thoroughly testing the link prior to posting references to it. I took the liberty of acquiring abstract text for those who are interested. Best Regards, Walt Williams, 97.12.04 dfheli@.............. http://www.pacificnet.net/~dfheli =================================================== TITLE: Artificial neural networks for seismic data interpretation Document ID: 19920011621 N (92N20863) File Series: NASA Technical Reports Report Number: AD-A245006 ESD-TR-91-170 Sales Agency & Price: CASI Hardcopy A03 CASI Microfiche A01 Authors: Lacoss, Richard T. (Massachusetts Inst. of Tech.) Cunningham, Robert K. (Massachusetts Inst. of Tech.) Curtis, Susan R. (Massachusetts Inst. of Tech.) Seibert, Michael C. (Massachusetts Inst. of Tech.) Published: Jun 30, 1991 Corporate Source: Massachusetts Inst. of Tech. (Lexington, MA, United States) Pages: 28 Contract Number: F19628-90-C-0002 NASA Subject Category: CYBERNETICS Abstract: This is the second Semiannual Technical Summary of the MIT Lincoln Laboratory Artificial Neural Networks for Seismic Data Interpretation project. The effort during this period has concentrated upon phase labeling and event recognition networks for use in the DARPA/NMRO Intelligent Monitoring System (IMS) for seismic surveillance. Perception networks were developed with standard IMS parameters as inputs, improving upon the phase labeling performance of the expert IMS. These networks were developed and tested using data sets containing 5,000 to 10,000 arrivals. An initial version of the expert system achieved a 79 percent success rate compared with 86 percent for the neural network. A more recent and improved version of the expert system achieved rates of 87 percent compared with 90 percent for an updated neural network. Phase labeling experiments with sonograms and three-component autoregressive modeling for signal representation did not lead to further improvement. Two event labeling experiments were carried out using three-component autoregressive signal models with Radial Basis Function classification networks and involved on the order of 200 events. Success rates were 96.6 percent for an earthquake/nonearthquake classification experiment and 91 percent for a Kola Peninsula event recognition experiment. These results, using only autoregressive waveform representations, are encouraging but very preliminary. Major Subject Terms: DATA BASES DATA PROCESSING EARTHQUAKES EXPERT SYSTEMS LOGIC CIRCUITS NEURAL NETS Minor Subject Terms: SEISMOLOGY SURVEILLANCE U.S.S.R. Language Note: English NASA Access Help Desk E-mail: help@............ Phone: 301-621-0390 FAX: 301-621-0134 ============================================================== TITLE: Artificial neural networks for seismic data interpretation Document ID: 19910022429 N (91N31743) File Series: NASA Technical Reports Report Number: AD-A239673 S/A-ANN-12-30-90 ESD-TR-91-058 Sales Agency & Price: CASI Hardcopy A03 CASI Microfiche A01 Authors: Lacoss, Richard T. (Massachusetts Inst. of Tech.) Cunningham, Robert K. (Massachusetts Inst. of Tech.) Curtis, Susan R. (Massachusetts Inst. of Tech.) Seibert, Michael C. (Massachusetts Inst. of Tech.) Published: Nov 30, 1990 Corporate Source: Massachusetts Inst. of Tech. (Lexington, MA, United States) Pages: 40 Contract Number: F19628-90-C-0002 NASA Subject Category: GEOPHYSICS Abstract: Seismic surveillance applications were reviewed and data interpretation tasks were selected for initial neural network experimentation. The selected tasks are estimation of signal arrival time (time picking), labeling of seismic phases, and recognition of typical and atypical events on a regional basis. Basic seismology and surveillance techniques are reviewed and preliminary experimental results are summarized. Two types of data are used. Seismic waveform data with associated parametric information are being provided by SAIC in San Diego, CA. Parametric data for a much larger data set are being obtained by remote access to an on-line data base at the Center for Seismic Studies (CSS) in Arlington, VA. All the data are from NORESS and ARCESS arrays in Scandinavia and were processed by the IMS (Intelligent Monitoring System) regional seismic surveillance system. At the start of the contract SAIC provided an initial waveform data set for exploratory experimentation. While using it, the waveform data requirements and formats were worked out with SAIC and the first installment of waveforms for 50 events was received. Major Subject Terms: NEURAL NETS ON-LINE SYSTEMS SEISMOLOGY WAVE PROPAGATION Minor Subject Terms: DATA BASES SURVEILLANCE WAVEFORMS Language Note: English NASA Access Help Desk E-mail: help@............ Phone: 301-621-0390 FAX: 301-621-0134 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Interesting AGU presentation Date: Thu, 04 Dec 1997 16:03:25 -0700 PSN- Sean Morrissey of Saint Louis University is making an interesting presentation at AGU about a feedback seismometer he has built that is similar to some of the SG systems employed by various PSN members. His presentation will be Wednesday, 10 Dec (see below), AN: S31B-12 LO: MC HALL D HR: 0830h DA: Wednesday TI: A Homemade High Resolution Broadband Vertical Seismometer Constructed From Consumer Hardware and Electronics Items for School and Personal Use AU: *S T Morrissey MN: Fall Meeting 1997 but unfortunately I will not be able to attend because I will be in Redwood City working with Larry Cochrane on the PSN presentation for that Friday (see below). AN: U51A-05 LO: MC HALL D HR: 0830h DA: Friday TI: Public Seismic Network (PSN): A Model for Preparing People to Use Real-Time Information About Natural Hazards AU: *E Cranswick, B Gardner, Public Seismic Network MN: Fall Meeting 1997 Apparently there is no online version of Sean's abstract on the AGU webpage , but he may have presented his material at some other website with which I am not familiar. -Edward -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Homemade High Resolution Broadband Vertical Seismometer Date: Thu, 04 Dec 1997 16:28:05 -0700 Sean- Dave Simpson of IRIS sent me a copy of your manuscript, "A High Resolution Broadband Vertical Seismometer Constructed from hardware store and consumer electronics components" (Sean-Thomas Morrissey) and the corresponding AGU abstract. I was very impressed by what a thorough job you have done in designing and building the device, explicating the mathematical theory (most of which I could not follow), recording such good-example waveforms, and producing such a well-integrated and professional-looking manuscript that documents it all. Though perhaps not quite as polished as your approach, several Public Seismic Network (PSN ) members have been building and recording feedback seismic sensors for several years, e.g., and . I regret that I will probably miss your presentation on Wednesday because I will still be working on the PSN presentation for Friday, AN: U51A-05 LO: MC HALL D HR: 0830h DA: Friday TI: Public Seismic Network (PSN): A Model for Preparing People to Use Real-Time Information About Natural Hazards AU: *E Cranswick, B Gardner MN: Fall Meeting 1997 but I hope to see you somewhere, sometime at AGU. -Edward -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: PS. Re: Homemade High Resolution Broadband Vertical Seismometer Date: Thu, 04 Dec 1997 16:35:01 -0700 Sean- Is there a website that displays some or all of your manuscript and abstract? -Edward -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: PS. Re: Homemade High Resolution Broadband Vertical Seismometer Date: Thu, 4 Dec 1997 20:02:45 -0600 (CST) Edward, I appreciate your interest in the homemade seismometer. I have not put any of the information on a web page because the project is entirely a "home-hobby" activity, and I don't want anyone to get the idea that I have been working on it on USGS funded time, although this latter situation may change drastically with the projected reduction of USGS seismic network funding. Many people have been urging me to get it on the web, including John Lahr, who has sent me info about the PSN. But until I have the documentaion much more complete (a matter of time), I don't want to start something that raises more questions than answers. The draft of the paper is, in fact, on my PC at home, so I couldn't even steer you to it via ftp from here. But one of my motivations for presenting it at the AGU is to put all the ideas into the public domain so that none of the instrumentation companies can tie them up with patents. In particular, the mounting of the leaf spring uniquely avoids all the problems of a clamped spring. And the very simple mechanical system shows that the transfer function of the instrument can be completely controlled by very simple electronics. I hope to see you at the meeting, possibly before your presentation. I am staying at the Mariott. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Seismo-Watch Update 971204 Date: Thu, 04 Dec 1997 20:05:11 -0700 Two items on the up side and two on the down side: * Santa Barbara News-Press features a Seismo-Watch Earthquake Report. * Santa Paula Times receives a custom Seismo-Watch Fax-Report. * Salt Lake Tribune discontinues their Seismo-Watch Report. * The Seismo-Watch Report on Contra Costa Television is suspended. 1) Santa Barbara News-Press. It is with great pleasure to announce that the Santa Barbara News-Press has agreed to feature a weekly Seismo Watch Earthquake Report beginning January, 4, 1998. Their report will be located on the Sunday Weather Page and include the M2+ earthquake activity from the central and southern California coastal region between San Juan Bautista to the Salton Sea. The report will also include a detailed inset map showing the local M1+ activity, a brief discussion box of the notable regional seismicity, and a Information Box where notable historic earthquake activity, earthquake terms, and preparedness tips will be reviewed. The Santa Barbara News-Press services more than 500,000 people of Santa Barbara County and surrounding areas. 2) Santa Paula Times. On November 10, the Santa Paula Times agreed to feature a special Seismo-Watch earthquake report within a local columnist's section of community affairs and events. They requested a custom Seismo-Watch fax-report for weekly M1+ earthquake activity of eastern Ventura County. The information is incorporated in a weekly column prepared by journalist, Peggy Kelly. The area of coverage is northwest of the Northridge aftershock zone and has typically shown low to moderate seismicity during the past few decades. Events are listed with date, time, longitude, latitude, depth and magnitude notations, and tallied by week, previous week and year to date. Brief descriptions are provided for M2+ events and detailed maps with specific descriptions shall be submitted for activity over M3. Santa Paula Times services the diverse communities of eastern Ventura County, principally of the central Santa Clara River Valley. 3) Salt Lake Tribune. It is with much regret but after nearly two years, the Salt Lake Tribune has decided to discontinue their Seismo-Watch Earthquake Report. They said they wanted to go another direction with their Health and Science section, which featured the earthquake report, and considering the currently low seismic activity in Utah, there was a lack of reader interest which warranted a change. They were not dissatisfied the service, but wanted to keep pace with their ever changing readership needs. They have kept the door open for future involvement if activity, and thus reader interest, were to increase. The last report will be issued on Thursday, December 11, 1997. Seismo-Watch began weekly service to the Salt Lake Tribune in February, 1996, presenting a regional seismicity map from southern Montana to the northern Arizona border highlighting, the ever active Yellowstone caldera. The publication was moved to a monthly schedule in October 1996 because of a low reader interest. I am sadden by the Tribunešs notification yet understand their position. I thank the Salt Lake Tribune for the opportunity to present timely earthquake information in their newspaper during the past two years and encourage residents in the area to do like wise. 4) Contra Costa Television. On November 17, 1997, Contra Costa Television (CCTV) agreed to suspend the television programming of the Seismo-Watch Earthquake Report. They had been receiving declining viewer participation in their "InfoNet Interactive" community message bulletin board and, although the Seismo-Watch Earthquake Report had maintained one of the top six visited sites on the system, the low viewer participation was not enough to encourage corporate financial support. The non-commercial program format featured 31 panels that presented weekly updates to global and regional seismicity, special earthquake reports, preparedness and safety tips, and contact numbers for more information. Viewers navigated the InfoNet Interactive site using a touch tone phone which displayed their selections on their television screens. CCTV is the government access television station for Contra Costa County, California, servicing more than 850,000 people. The program was graciously sponsored by the Contra Costa Office of Emergency Services. Advanced Geologic Exploration and CCTV welcome suggestions for maintain this valuable programming. The parties will review the situation during the first quarter of 1998. A web site is being constructed to show the programming and a notification will be issued upon its completion. -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ken Navarre Subject: hobbist et al... Date: Thu, 4 Dec 1997 20:31:23 -0800 (PST) On Thu, 4 Dec 1997, S-T Morrissey wrote: (snip) > I appreciate your interest in the homemade seismometer. I have not > put any of the information on a web page because the project is > entirely a "home-hobby" activity, and I don't want anyone to get > the idea that I have been working on it on USGS funded time, although > this latter situation may change drastically with the projected > reduction of USGS seismic network funding. (snip) While the number of us "hobbist" is growing that is not the only group interested in sensors or telemetry systems that we can operate ourselves. I work for a municipality and have a system running in the administration offices of our city's water quality control plant. I've been working to increase the interest of the city "fathers" to the extent that we will have a system running SDR in the lobby of our municipal services building. Looks as if I may be able to have access to a dedicated microwave link to bring the signals from more distant telemetry sites to our offices. The positive press that you folks are producing is helping increase the awareness of seismicity and our needs to maintain (and expand) the network. Guess I should also thank the Gods for nudging Mammoth along a bit. A *little* shaking leads to a nervous public and that can make the politicos shake a few more shillings into the scientific coffers. (or one could hope...) Everybody take care. Ken _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Charlie Rond Subject: Quake? Date: Thu, 04 Dec 1997 17:54:11 -0600 I'm recording something sizeable 11:54UTC. Anybody know where it is? Charlie Rond -\/\--Public Seismic Network-Memphis rond@................ (901) 360-0302 [ free BBS ] http://gandlf.ceri.memphis.edu/~rond http://gandlf.ceri.memphis.edu/~rond/psn _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Quake? Date: Sat, 06 Dec 1997 00:15:30 +1200 can't say yet charlie, still waiting for the next update on the live seismic server nothing showing there yet, the las decent ones thay show are the Ms5.3 and Mb5.1 in Guatemala at 1456hrs and 2214 hrs UTC respect. Dave At 05:54 PM 12/4/97 -0600, you wrote: >I'm recording something sizeable 11:54UTC. Anybody know where it is? > > Charlie Rond -\/\--Public Seismic Network-Memphis > rond@................ (901) 360-0302 [ free BBS ] > http://gandlf.ceri.memphis.edu/~rond http://gandlf.ceri.memphis.edu/~rond/psn Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "jean-jacques HUNSINGER" Subject: Re: Quake? Date: Fri, 5 Dec 1997 13:29:36 +0100 -----Message d'origine----- De : Charlie Rond Ŕ : PSN-L@............. Date : vendredi 5 décembre 1997 12:56 Objet : Quake? >I'm recording something sizeable 11:54UTC. Anybody know where it is? hi, I'm recording the same event, beginning at 11h40 UTC here in France, and now, the amplitude is saturated. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Quake? Date: Sat, 06 Dec 1997 00:54:18 +1200 Looks like a possib. M6++ event in the Kamchatka Peninsula Nth Pacific there has been a whole mass of events there over the last couple of days including a couple of M5+ events will confirm soon Dave >>I'm recording something sizeable 11:54UTC. Anybody know where it is? > >hi, >I'm recording the same event, beginning at 11h40 UTC here in France, and >now, the amplitude is saturated. Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: fmurray@......... (frank murray) Subject: Re: Quake? Date: Fri, 05 Dec 1997 12:52:10 GMT On Fri, 5 Dec 97 12:29:36 +0000, you wrote: > >-----Message d'origine----- >De : Charlie Rond >=C0 : PSN-L@............. >Date : vendredi 5 d=E9cembre 1997 12:56 >Objet : Quake? > > >>I'm recording something sizeable 11:54UTC. Anybody know where it is? > >hi, >I'm recording the same event, beginning at 11h40 UTC here in France, and >now, the amplitude is saturated. a 7.7 off the coast of kamchatka...usgs briefly flashed it as a series of M2 and M3 quakes in southern cal... frank fmurray@......... for my electronic college proposal see: http://home.att.net/~fjtmurray/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Quake? Date: Sat, 06 Dec 1997 01:06:26 +1200 yeah all the chinese and russian on line seismographs are all saturating definately a big one pity a lot of the online seismo's are not working eg hawaii, and the two USA ones as they would give a good record prob. not overloaded because of their distance Dave > >a 7.7 off the coast of kamchatka...usgs briefly flashed it as a series >of M2 and M3 quakes in southern cal... >frank Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ray Gallagher Subject: Re: Quake? Date: Fri, 05 Dec 1997 05:07:03 -0800 e0439a0-w- f o NWS-PKZ130-122-121-520-5 12-05 0393 PKZ130-122-121-520-510-320-330-321-310-410-400-220-221-233- 230-231-210-211-120-110-PZZ130-131-133-134-132-135-150-051340- TSUNAMI BULLETIN NUMBER 2 WEST COAST AND ALASKA TSUNAMI WARNING CENTER/NOAA/NWS ISSUED DEC 5 AT 1240 UTC ..A TSUNAMI WARNING AND WATCH ARE IN EFFECT... THIS IS A TSUNAMI WARNING FOR THE COASTAL AREAS FROM DUTCH HARBOR, AK. TO ATTU, AK., INCLUSIVE. A TSUNAMI WATCH IS IN EFFECT FROM THE NORTH TIP OF VANCOUVER ISLAND, BC. TO SAND POINT, ALASKA. AT THIS TIME, THIS BULLETIN IS FOR INFORMATION ONLY FOR OTHER AREAS OF CALIFORNIA, OREGON, WASHINGTON, AND BRITISH COLUMBIA. AN EARTHQUAKE, PRELIMINARY MAGNITUDE 7.7, OCCURRED AT 0227 AST ON DEC 5, OR 0327 PST ON DEC 5, OR 1127 UTC ON DEC 5. THE EARTHQUAKE WAS LOCATED IN THE GENERAL AREA OF: KAMCHATKA NEAR 55.0N, 163.1E. THE PACIFIC TSUNAMI WARNING CENTER AT EWA BEACH, HAWAII WILL ISSUE BULLETINS FOR OTHER AREAS OF THE PACIFIC. EVALUATION: IT IS NOT KNOWN /REPEAT NOT KNOWN/ IF A TSUNAMI EXISTS, BUT A TSUNAMI MAY HAVE BEEN GENERATED. THEREFORE, PERSONS IN LOW LYING COASTAL AREAS SHOULD BE ALERT TO INSTRUCTIONS FROM THEIR LOCAL EMERGENCY OFFICIALS. PERSONS ON THE BEACH SHOULD MOVE TO HIGHER GROUND IF IN A WARNED AREA. TSUNAMI WAVE HEIGHTS CANNOT BE PREDICTED AND MAY BE A SERIES OF WAVES WHICH COULD BE DANGEROUS FOR SEVERAL HOURS AFTER THE INITIAL WAVE ARRIVAL. ESTIMATED TIMES OF INITIAL WAVE ARRIVAL FOR WATCH/WARNING AREAS: SEWARD, AK 0750 AST DEC 5 HOMER, AK 0845 AST DEC 5 LANGARA, BC 0910 PST DEC 5 KODIAK, AK 0722 AST DEC 5 KETCHIKAN, AK 0922 AST DEC 5 SAND PT., AK 0635 AST DEC 5 SITKA, AK 0803 AST DEC 5 COLD BAY, AK 0701 AST DEC 5 JUNEAU, AK 0925 AST DEC 5 DUTCH HARBOR, AK 0544 AST DEC 5 YAKUTAT, AK 0802 AST DEC 5 ADAK, AK 0443 AST DEC 5 CORDOVA, AK 0821 AST DEC 5 SHEMYA, AK 0339 AST DEC 5 VALDEZ, AK 0812 AST DEC 5 FOR INFORMATION ONLY: LA JOLLA, CA 1216 PST DEC 5 CHARLESTON, OR 1051 PST DEC 5 SAN PEDRO, CA 1205 PST DEC 5 SEASIDE, OR 1059 PST DEC 5 SAN FRANCISCO,CA 1143 PST DEC 5 ASTORIA, OR 1123 PST DEC 5 CRESCENT CITY,CA 1058 PST DEC 5 NEAH BAY, WA 1047 PST DEC 5 TOFINO, BC 1037 PST DEC 5 BULLETINS WILL BE ISSUED HOURLY OR SOONER IF CONDITIONS WARRANT. THE TSUNAMI WATCH/WARNING WILL REMAIN IN EFFECT UNTIL NOTICE. EDIS-12-05-97 0451 PST _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Seisguy Subject: Re: Quake? Date: Fri, 5 Dec 1997 09:55:24 EST Good Morning December 5, 1997 Looks like the 7.7 quake was joined by a volcanic eruption. If Mammoth goes, do we expect such a big quake also? A 7.7 at that location would touch L.A., San Francisco, Vegas, & Sacramento wouldn't it? Mike O'Bleness Northridge, Ca MOSCOW, Dec 5 (Reuters) - One of the most active volcanoes in Russia's Far East region of Kamchatka began erupting on Friday for the second time this year, spewing a column of ashes into the sky, the Emergencies Ministry said. The Bezymyanny volcano started erupting after seismic activity in the Bering Sea off Kamchatka's eastern coast, ministry officials said. An earthquake registering about five on the Richter scale was detected in the early hours on Friday. ``The column (from the volcano) was eight km (five miles) high. There are no victims,'' a ministry spokeswoman told Reuters. ``The people in nearby settlements are in no danger. The closest is about 60-80 km (40-50 miles) away from the eruption site.'' Officials said the situation would nonetheless be monitored closely in case people had to be evacuated. Itar-Tass news agency quoted volcano experts as saying the trail of ashes was 20 km (12 miles) long and could be seen moving to the northeast in the direction of the Pacific Ocean. But it said U.S. satellites registered the plume of ashes as being 100 km (60 miles) long. ``The satellites registered a heat spot over the volcano on Thursday. However, ground services showed no seismic fluctuations signalling that an eruption was about to start,'' Tass said. It said Bezymyanny was one of the most active volcanoes in the Kamchatka region. The last eruption occurred in May. ^REUTERS@ 02:46 12-05-97 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Interesting AGU presentation Date: Fri, 5 Dec 1997 10:43:25 -0500 Is there any way to get a pre-print or re-print from Morrissey about his SG? Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Streckeisen seismometers Date: Fri, 5 Dec 1997 10:43:23 -0500 Meridith, There is a fabulous paper on the leaf-spring seismometers:Weilandt & Streckeisin, "The Leaf-Spring Seismometer:Design and Performance", Bull. Seismological Soc. of Am., vol 72 no 6 pp 2349-2367, Dec 1982. Your local library can probably get you a photocopy of this. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Re: Force of Lehman susp. wire Date: Fri, 5 Dec 1997 10:43:27 -0500 Charles Patton, I will ftp a .GIF file of my drawing of the Zollner suspension (I hope,= I'm uncertain about sending this sort of stuff). I think that you will b= e able to see it by doing ftp://psn.quake.net/incoming/zollner.gif As the drawing shows, I made a (very crude) mock-up and got a nice long= period. The wire from the end of the boom to the frame can be very thin (and hence flexible) because there is very little load on it. The center of rotation of the boom seems to be the point of attachment of= the wire to the frame and this point is the one which must be slightly behind the upper suspension point. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Edward Cranswick's PSN schedule Date: Fri, 05 Dec 1997 11:19:51 -0700 PSN- During the period 5-21 December 1997, I will be out of the office in Golden, Colorado, and in the San Francisco Bay Area to particpate in the PSN presentation at AGU on 12 Dec and attend the Northern California PSN Meeting at USGS Menlo Park on 20 Dec. I will be spending much of that time working with Larry Cochrane so you can contact me through him if necessary. I wish you all happy holidays. -Edward -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: [Fwd: Explosive eruption of Bezymianny] Date: Fri, 05 Dec 1997 10:44:37 -0700 The Bezymianny erupion occurred prior to the Kronocki Peninsula M7.7 earthquake. Sipkin obtained a hypocenter depth of 14 km suggesting suface fault ruptures are likely! -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com This release is based on information received from KVERT (Kamchatka Volcanic Eruption Response Team) beginning about 11:30 AM AST and continuing throughout the day and several satellite passes. Bezymianny Volcano 55o58' N, 160o36'E, Elevation 2,882 m (9,453') Bezymianny volcano began an explosive eruption today probably about 9:30 AM AST based on seismic activity. As of 3:15 PM AST today, KVERT (Kamchatka Volcanic Eruption Response Team) was estimating the eruption plume height had reached 9 km (~30,000') ASL up from 6 km (~20,000') ASL earlier in the day. A satellite image at 4:30 PM AST indicated the ash cloud extended as far as 250 km to the east. A growing hot spot on Bezymianny volcano has been monitored on satellite images by AVO remote sensing specialists for the past 2 days. This hot spot was not accompanied by unusual seismicity or by an ash plume and is assumed to be related to small debris avalanches of the Bezymianny dome. An abrupt increase in seismicity was noted this morning at 9:30 AM AST. Bezymianny volcano is a frequently active, explosive volcano whose last significant eruption was in October 1995. The volcano experienced a violent Mount St. Helens type lateral blast and dome emplacement in 1956 and has had several partial dome collapses in recent years. A large lava dome has continued to grow sporadically in the summit crater. PLEASE CONTACT AVO IF YOU HAVE QUESTIONS OR COMMENTS. Dr.Vladimir Kirianov Dr.Tom Miller Kamchatka Volcanic Eruptions Alaska Volcano Observatory Response Team, IVGG, Piip Blvd, 9 4200 University Drive Petropavlovsk-Kamchatsky,683006,RUSSIA. Anchorage, Alaska 99508 E-mail:ivgg@.................. e-mail:futpm@................. attn: tel. (415-22) 59514 tel. (907) 786-7454 From: "Charles R. Patton" Subject: Re: Force of Lehman susp. wire Date: Fri, 05 Dec 1997 16:21:24 -0800 Bob, I just looked at the Zollner .gif file. I see you got it uploaded. That is a very interesing suspension. Thanks. Charles Patton home: patton@......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Quake? Date: Fri, 5 Dec 1997 17:09:59 -0800 (PST) Hi Mike: You are correct to assume increased seismic activity after the future eruption of Mammoth (Long Valley)caldera. I expect you could have sympathetic earthquakes from it in the areas nearby to as far away as Yellowstone. The magnitude could be large to great in size. The Owens Valley is the site of one of California's biggest earthquakes (1872). The area around Independence/Lone Pine was the epicenter. It was a M8.0 followed by a M6.5 aftershock. The surface fracture was from Big Pine to Olancha. The displacement was 6-7 meters. All not very far away from the site of all the latest activity! I hope that helps you, Frank Condon mail to:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" >Good Morning December 5, 1997 > >Looks like the 7.7 quake was joined by a volcanic eruption. If Mammoth goes, >do we expect such a big quake also? A 7.7 at that location would touch L.A., >San Francisco, Vegas, & Sacramento wouldn't it? > >Mike O'Bleness >Northridge, Ca > > >MOSCOW, Dec 5 (Reuters) - One of the most active volcanoes in Russia's Far >East region of Kamchatka began erupting on Friday for the second time this >year, spewing a column of ashes into the sky, the Emergencies Ministry said. > >The Bezymyanny volcano started erupting after seismic activity in the Bering >Sea off Kamchatka's eastern coast, ministry officials said. An earthquake >registering about five on the Richter scale was detected in the early hours on >Friday. > >``The column (from the volcano) was eight km (five miles) high. There are no >victims,'' a ministry spokeswoman told Reuters. > >``The people in nearby settlements are in no danger. The closest is about >60-80 km (40-50 miles) away from the eruption site.'' > >Officials said the situation would nonetheless be monitored closely in case >people had to be evacuated. > >Itar-Tass news agency quoted volcano experts as saying the trail of ashes was >20 km (12 miles) long and could be seen moving to the northeast in the >direction of the Pacific Ocean. > >But it said U.S. satellites registered the plume of ashes as being 100 km (60 >miles) long. > >``The satellites registered a heat spot over the volcano on Thursday. However, >ground services showed no seismic fluctuations signalling that an eruption was >about to start,'' Tass said. > >It said Bezymyanny was one of the most active volcanoes in the Kamchatka >region. The last eruption occurred in May. ^REUTERS@ > >02:46 12-05-97 > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Quake? Date: Fri, 5 Dec 1997 17:15:37 -0800 (PST) Hi Dave: Earlier today, there was a M4.0 located near Yucaipa! An aftershock of the Lander's earthquake according to the geologists at Caltech. Frank Condon Mail to:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" > yeah all the chinese and russian on line seismographs are all saturating > > definately a big one pity a lot of the online seismo's are not working >eg hawaii, and the two USA ones as they would give a good record prob. not >overloaded because of their distance > >Dave >> >>a 7.7 off the coast of kamchatka...usgs briefly flashed it as a series >>of M2 and M3 quakes in southern cal... > >>frank > >Co-ordinator: >New Zealand >Public Seismic Network > Dave A. Nelson ZL4TBN > 24 Jensen St., > Green Is., Dunedin, > South Is.. New Zealand. > >http://psn.quake.net/dave/home.htm > >IF there indeed are other parallel universes... I can now rest in the >knowledge, that in at least one of them, I am filthy rich and drive a red >Ferrari > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Al Allworth Subject: Re: Zohlner suspension Date: Fri, 5 Dec 1997 19:46:56 -0800 (PST) At 10:43 AM 12/5/97 -0500, you wrote: >Charles Patton, > I will ftp a .GIF file of my drawing of the Zollner suspension I have seen drawings of this suspension but didn't associate the name Zohlner with it. Is anything done to suppress the parasitic responses that might be present due to motion at the rear of the boom in at least two axis? Maybe because they would be much higher in frequency, filtering would effectively remove their effect. Just a thought. It looks interesting, though. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stvnsak Subject: Virgin Is. Date: Sat, 6 Dec 1997 03:55:26 EST Hello all, Has there been any unusual activity seismic/volcanic, in the virgin Is. recently? Thank you. Sincerly, Joseph Stevens _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Charlie Rond Subject: Re: Quake? Lost E-mail! Date: Fri, 05 Dec 1997 15:50:38 -0600 I saw messages streaming in from a number of you when I downloaded email Friday night. Then all the new mail was gone in a flash - as if deleted! Fortunately, there is Larry's PSN website, and I saw that what I was asking about was the 7.7 Kamchatka event. If any of you sent inquiries or something I should respond to, please email me again. Thanks.. Charlie Rond -\/\--Public Seismic Network-Memphis rond@................ (901) 360-0302 [ free BBS ] http://gandlf.ceri.memphis.edu/~rond http://gandlf.ceri.memphis.edu/~rond/psn _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Richard A. Webb" Subject: WWV Antenna Date: Sat, 06 Dec 1997 08:28:37 -0500 I recently obtained a short wave radio that I will be using in conjunction with Larry,s A/D board. Using the antenna that came with the radio seems less than satisfactory in that the signal comes and goes and has a lot of noise. Most likely I need an external antenna. I have a choice of 5 frequencies (2500 kHz, 5,000 kHz, 10,000 kHz, 15000 kHz and 20 kHz) and seem to have the best luck with the lower frequencies. I am planning on installing an external antenna and would like suggestions on design. I seem to recall that a simple folded dipole of a specific length is the way to go. Any advice? Dick _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: WWV Antenna Date: Sat, 06 Dec 1997 08:40:22 -0600 Richard A. Webb wrote: > > I recently obtained a short wave radio that I will be using in conjunction > with Larry,s A/D board. Using the antenna that came with the radio seems > less than satisfactory in that the signal comes and goes and has a lot of > noise. Most likely I need an external antenna. I have a choice of 5 > frequencies (2500 kHz, 5,000 kHz, 10,000 kHz, 15000 kHz and 20 kHz) and > seem to have the best luck with the lower frequencies. I am planning on > installing an external antenna and would like suggestions on design. I > seem to recall that a simple folded dipole of a specific length is the way > to go. Any advice? > > Dick > Welcome to the wonderful world of HF radio propagation.:) You are correct in that the lower frequencies will be avaliable more often than the higher frequencies. Unfortunately they are also subject to more manmade interference. A dipole for the lower frequencies is quite large so unless you have the room for it I would reccomend just trying a length of wire strung outside. The wire has the advantage of not being tuned to a specific frequency so you may change frequencies if necessary. A good source of information on antenna design and radio propagation is "The Radio Amateur's Handbook" published by the American Radio Relay League. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: bob ogburn Subject: Re: WWV Antenna Date: Sat, 06 Dec 1997 07:21:03 -0800 Using WWV can be somewhat problematic, based on the receiving location. High Frequency (HF or "short-wave") reception is subject to propagation problems. At different time during the local (receiving location) day, the signal from WWV will be stronger on a specific frequency. In my location, the lower frequencies are best during hours of darkness and the higher frequencies are best during daylight hours. A simple half-wave folded dipole antenna may be constructed using 300 ohm "twin lead" cable (used for TV antenna feed line). Obtain enough unshielded, flat 300 ohm twin lead (the length needed is the sum of the dipole dimension and the feed line distance from the dipole to the receiver. Dipole length in feet is calculated by dividing 468 by the operating frequency. For operation on 10 MHz, the dipole is 46.8 feet (14.25 meters)). Connect both conductors at the ends of the dipole and solder, locate the center of the dipole and cut the conductor on ONE SIDE of the twin lead. Connect the feed line to the exposed conductors on the dipole and provide mechanical support for the connection. The resulting assembly resembles the letter 'T'. Connect the feed line free end to the receiver external antenna connector (if the receiver has an unbalanced antenna input, a TV 300 to 75 ohm matching transformer is required here). Suspend the dipole using insulated material at the ends so that the diople is broadside to the transmitting station location (WWV in Colorado, or WWVH in Hawaii). Remember that antenna must be installed so that it does not create a safety problem. It should be positioned so that it is not a physical hazard, and more importantly, the antenna must never be installed near power lines. This antenna will operate on all of the HF NIST broadcasts because the frequencies are harmonically related, if you have the necessary space, calculate and construct the antenna for the lowest frequency that you can reliably receive. references: The Radio Amateur's Handbook, ARRL Richard A. Webb wrote: > > I recently obtained a short wave radio that I will be using in conjunction > with Larry,s A/D board. Using the antenna that came with the radio seems > less than satisfactory in that the signal comes and goes and has a lot of > noise. Most likely I need an external antenna. I have a choice of 5 > frequencies (2500 kHz, 5,000 kHz, 10,000 kHz, 15000 kHz and 20 kHz) and > seem to have the best luck with the lower frequencies. I am planning on > installing an external antenna and would like suggestions on design. I > seem to recall that a simple folded dipole of a specific length is the way > to go. Any advice? > > Dick > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Virgin Is. Date: Sat, 06 Dec 1997 07:51:29 -0700 Please find the attached earthquake report from the Puerto Rico seismic network for November 1997. You can find past report issues at: http://www.seismo-watch.com/EQSERVICES/CurrentActivity/CaribbeanLinks.html Try the snorkling at Cinnaman Cove on the north side of St. Johns. Mighty nice! -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com From: shammon1@............. Subject: Re: Virgin Is. Date: Sat, 06 Dec 1997 12:44:50 -0800 Charles Watson wrote: > > Please find the attached earthquake report from the Puerto Rico seismic > network for November 1997. You can find past report issues at: > > http://www.seismo-watch.com/EQSERVICES/CurrentActivity/CaribbeanLinks.htm The home page is also worth a look, http://rmsismo.upr.clu.edu/ if you are into homepage design. Regards, Steve Hammond PSN San Jose, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: WWV Antenna Date: Sun, 07 Dec 1997 10:12:23 +1200 Dick, don't get carried away with a tuned length at those freqs. too BIG too much effort for just a receive system in New Zealand I also receive WWV/H for time keeping and solar activity info and a "long wire antenna " is absolutely ideal and as Jim said it is them usable over all freqs. with very little difference noticed over a tuned antenna. if you are transmitting then IT IS ESSENTIAL to have a tuned antenna for the transmitter to look into. As any of my fellow amateur radio operators will tell you Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Caruso Subject: Re: WWV Antenna Date: Sat, 6 Dec 1997 19:29:40 -0500 (EST) Dave, I agree. the length of the antenna is not critical on reception. I (pardon my ignorance):-? am wondering exactly what are the wwv/wwvh frequencies? I have recently been trying to reassemble my lehman and get in tune! I have a dataq a/d converter that seems to track time pretty well. It outputs in various formats. 1. Ascii (sequential) 2. Binary (wCODAS header) 3. Binary (w/out codas header) 4. Asyst(ant) 5. Spreadsheet print 6. Dadisp 7. Easyest LX or AG I haven't had time to peruse the archives I have saved, seem to be having a problem w/my original preamp operating at less than optimal efficiency. I have used electrolytics and some mylar caps. STEPHEN CARUSO CET KB8UGH "Coincidence is a shortsighted mental delusion" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: WWV Antenna Date: Sun, 07 Dec 1997 13:18:08 +1200 Stephen, hi ya, 2.5, 5.0 10.0, 15.0, 20.0 MHz in NZ I get the 5 and 10 Meg ones well only ocassionaly hear the 15 meg freq. ok on the pre-amp probs. I will send you a gif of the preamp I use its very straight forward , low component count, works very well. I have build 6 of them 3 being used at home 3 else where wiil post gif to you directly save filling everyones mailbox Dave At 07:29 PM 12/6/97 -0500, you wrote: >Dave, I agree. the length of the antenna is not critical on reception. > I (pardon my ignorance):-? am wondering exactly what are the wwv/wwvh >frequencies? I have recently been trying to reassemble my lehman and get >in tune! I have a dataq a/d converter that seems to track time pretty >well. It outputs in various formats. >1. Ascii (sequential) >2. Binary (wCODAS header) >3. Binary (w/out codas header) >4. Asyst(ant) >5. Spreadsheet print >6. Dadisp >7. Easyest LX or AG > >I haven't had time to peruse the archives I have saved, seem to be having >a problem w/my original preamp operating at less than optimal efficiency. >I have used electrolytics and some mylar caps. > >STEPHEN CARUSO CET >KB8UGH >"Coincidence is a shortsighted mental delusion" > > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Andy Loomis Subject: Preamps, Filters and WWV Date: Sat, 6 Dec 1997 19:08:07 -0700 (MST) After following the postings for the past several days, I believe I may be able to contribute some worthwhile ideas to the network, too. We have constructed several of the Lehman-type seismometers at the University of Northern Colorado (in Greeley) as student projects, and have enjoyed marvelous success in the design and construction of incredibly low-noise seismic preamplifiers and filters. The designs have evolved over the past few years into what I believe is the most cost-effective, professional-grade instrumentation available. If you would be interested in reading about them, I have just developed a rather extensive webpage at: http://www.info2000.net/~aloomis/seismom.htm The website contains complete electronic descriptions, together with schematic diagrams. I've also included a very effective time-marker decoder for WWV reception. My specialty is instrumentation electronics, so you'll note that the site is still rather weak on the treatment of the mechanical aspects of the seismometers. -- Andy Loomis Senior Telecommunications & Electronics Splst. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Preamps, Filters and WWV Date: Sun, 07 Dec 1997 15:13:09 +1200 Andy, hmmmm interesting, prob. good for the long period seismometers but the filtering is toooo hefty for use with short period seismometers that are in wide use I find it is more useful to have the freq cutoff ~10 - 15 hz so as not to miss the genuine higher freq seismic signal and then use software filtering to get rid of the unwanted crud this is where Larry C's Winquake analysis software really comes into its own by using the FFT features. on a local quake with plenty of 1- 10 hz signal you can do hi pass filtering and get rid of the low freq noise with a teleseism which is predominantely less than 1 sec period it is then easy to do a low freq. pass filter and get rid of the high freq manmade noise the notch filter is also very useful as Phil G. has discovered his NS seismom. has a oscill. that often occurrs at 4.5 hz this results in a large spike in the FFT at that freq. using the notch filter it can be eliminated to produce a great looking event trace.. Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Andy Loomis Subject: Re: Preamps, Filters and WWV Date: Sat, 6 Dec 1997 21:00:58 -0700 (MST) Hi Dave, Yes, I designed the filter/s for teleseismic monitoring rather than for anything local. In my area, Colorado, there is very little seismic activity that a 1-Hz filter would obscure. Most of the seismometers we have made are eventually given to public schools for classroom use and the filtering comes in mighty handy in those environments, as you can imagine. I tend to forget that there are some folks who are close enough to tremors to actually FEEL them! For the benefit of those who care to change the cutoff frequency of the Butterworth filter to the 12 - 15 Hz range, the 5.1 meg resistors should be changed to 100-K ohms, and the capacitors from 0.22 to 0.1 uF. I plan to check out the Winquake software as you mentioned. It sounds terrific. Thanks for the tip! - Andy >Andy, >hmmmm interesting, prob. good for the long period seismometers but the >filtering is toooo hefty for use with short period seismometers that are >in wide use I find it is more useful to have the freq cutoff ~10 - 15 >z so as not to miss the genuine higher freq seismic signal and then use >oftware filtering to get rid of the unwanted crud this is where Larry >C's Winquake analysis software really comes into its own by using the >FFT features. >on a local quake with plenty of 1- 10 hz signal you can do hi pass >filtering and get rid of the low freq noise >with a teleseism which is predominantely less than 1 sec period it is >then easy to do a low freq. pass filter and get rid of the high freq >manmade noise the notch filter is also very useful as Phil G. has >discovered his NS seismom. has a oscill. that often occurrs at 4.5 hz >this results in a large spike in the FFT at that freq. using the notch >filter it can be eliminated to produce a great looking event trace.. >Dave >Co-ordinator: >New Zealand >Public Seismic Network _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Yucaipa M4.0 on San Andreas? Date: Sat, 6 Dec 1997 22:22:17 -0800 (PST) Hello All: Was the recent M4.0 earthquake in Yucaipa, CA that occurred last Friday located on the San Andreas fault? I figure it was at least within 1.5 miles from the Mill Creek ranger station which is right on top of it. Caltech listed it as an aftershock of the Landers earthquake. Although it was considered "significant" according to them. I wonder if this inactive part of the fault is starting to come to life? And I've heard that this section of the San Andreas might even be on a "thrust fault." Frank Condon mail to:frankcnd@.......... "Located in the seismic corridor somewhere between fontana & Mammoth Lakes" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: fmurray@......... (frank murray) Subject: Re: Yucaipa M4.0 on San Andreas? Date: Sun, 07 Dec 1997 06:29:00 GMT On Sun, 7 Dec 97 06:22:17 +0000, you wrote: >Hello All: >Was the recent M4.0 earthquake in Yucaipa, CA that occurred last Friday=20 >located on the San Andreas fault? I figure it was at least within 1.5 = miles=20 >from the Mill Creek ranger station which is right on top of it. Caltech=20 >listed it as an aftershock of the Landers earthquake. Although it was=20 >considered "significant" according to them. I wonder if this inactive = part=20 >of the fault is starting to come to life? And I've heard that this = section=20 >of the San Andreas might even be >on a "thrust fault." the below from usgs: Region: Southern California 4 mi. NNE of YUCAIPA 17 mi. E of SAN BERNARDINO 66 mi. E of PASADENA 17 mi. S of PFIZER (quarry) 13 mi. SW of Big Bear EQ (28 JUN 1992, 6.4 Mw) 1 mi. NNW of the SAN ANDREAS FAULT frank fmurray@......... for my electronic college proposal see: http://home.att.net/~fjtmurray/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Arie Verveer Subject: Levelling Screws Date: Sun, 07 Dec 1997 19:15:32 +0800 Hi, I've slowly been putting together a seismometer utilizing Larry's S_G parts and a friend of mine suggested that I should post the various construction stages . It seemed a good idea and an excuse to make a web page. The information is a little old, but here goes. Construction note: Levelling Screws at http://www.iinet.com.au/~ajbv/ Should I continue ? Arie Verveer ajbv@............ Hi,

I've  slowly been putting together a  seismometer  utilizing Larry's  S_G parts and a
friend of mine suggested that I should post the various construction stages . It seemed a
good idea and an excuse to make a web page. The information is a little old,  but here goes.

 Construction note: Levelling Screws   at             http://www.iinet.com.au/~ajbv/

Should I continue ?

Arie Verveer

ajbv@............ From: Frank Allen Subject: RE: Levelling Screws Date: Sun, 7 Dec 1997 09:57:57 -0500 I would like it if you would continue. Should I continue ? Arie Verveer ajbv@............ << File: ATT00001.htm >> From: "M. Luly" Subject: Help: Burr-Brown D/A Boards Date: Sun, 7 Dec 1997 15:01:15 -0500 I've been thinking about building a seismograph since I first saw the Amateur Scientist "Blue Book Collection" as a kid in the '60s. I've = inched closer to that goal now that a firend gave me a box of ~10 year o= ld Burr Brown I/O boards. The digital I/O and analog output boards had neve= r been opened and were complete with software and disks. Alas, the analog input board was opened and has no documentation. = Here is what I know: PCI-20089W-1 Analog Input Board 16/8 analog input channels (single-ended/differential) 12-bit Resolution Prgrammable Gain Amplifier (Gain=3D1,10,100) Up to 32 kHz Sample Rate Does anyone know have documentation on this? I have some BASIC drivers= , but am interested in the Pascal or C drivers. I've looked at the Burr-Brown web site, but they don't even list it on their discontinued page. Thanks. Matt Luly Lancaster, NY Matthew_Luly@.............. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: WWV Antenna Date: Sun, 7 Dec 1997 15:34:12 -0500 Dick, I'm in New Jersey, a long way from Colorado. I have just a wire about = 20 feet long suspended by a string hanging from a tree limb. This antenna i= s not tuned and is omnidirectional. WWV is solid most of the time, esp. 10= & 15 MHZ. = Try someting simple before going to the trouble of a dipole. Bob Barns KB2IKC _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: shansen@........ (shansen) Subject: Re: WWV Antenna Date: Sun, 7 Dec 1997 19:59:22 -0500 (EST) Just to add one more input on the WWV antenna topic. I have a dedicated WWV receiver in NH. The antenna was a 30 ft. long wire going from my chimney to a nearby tree. About 4 years ago the insulator at the far end of the wire broke leaving the antenna dangling down the chimney. Someday I'll put the thing back up but it remains adequate. This all to support the approach of try the simplest thing before going to any great lengths. Steve Hansen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: Levelling Screws Date: Sun, 07 Dec 1997 21:08:20 -0600 Arie Verveer wrote: > > Hi, > > I've slowly been putting together a seismometer utilizing Larry's > S_G parts and a > friend of mine suggested that I should post the various construction > stages . It seemed a > good idea and an excuse to make a web page. The information is a > little old, but here goes. > > Construction note: Levelling Screws at > http://www.iinet.com.au/~ajbv/ > > Should I continue ? > > Arie Verveer I had a look at the leveling screws on the web site. Beautiful machine work! A while back the two pitch leveling screw idea was posted on this list. Someone pointed out that you can get automotive studs with different pitches on each end. This is a way to do it if you don't have access to a machine shop. Please keep up the information. -- -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Magnetic spring seismometer improvement? Date: Mon, 08 Dec 1997 19:14:29 -0800 Roger (Baker), I have been pondering the problem of shielding a magnetic spring per your beam/repulse magnet seismometer, and think I may have a solution. I posted a GIF file on Larry's site at: ftp://psn.quake.net/incoming/sns-beam.gif Now, for the moment, imagine that the "Ferro" pieces are not present. When any vertical component of an external magnetic field is applied (as from fluctuations of the Earth's magnetic field), the effect is to cause an increase in the attraction of the two magnets. Forget that they are repulsing, and just think of them as ferromagnetic. Their permeability will concentrate some of the vertical field applied and cause the pieces to at- tract. This will happen even though the magnets are generally repulsing each other. The effect will be very small, but direct- ly proportional, and in addition to the overall magnet field. Now assume that the beam is ferromagnetic and thick enough that it does not saturate, but instead acts as a keeper, sending the flux back to the lower side magnets. If the upper ferro pieces are added, and have a similar permeability to the lower pieces, when a vertical component of an external uniform field (essen- tially the definition of flux from the Earth's field) is applied, then we have just balanced the attractive forces top and bottom for this external field and there will be no disturbance to the beam position. Obviously, this doesn't fix the temperature sensitivity of the magnets. But probably temperature control is easier than the problem of low level magnetic shielding. Anyway, just a thought. Charles R. Patton, Editor, Geo-Monitor patton@......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Magnetic spring seismometer improvement? Date: Mon, 08 Dec 1997 21:44:55 -0800 Roger (Baker), I have been pondering the problem of shielding a magnetic spring per your beam/repulse magnet seismometer, and think I may have a solution. I posted a GIF file on Larry's site at: ftp://psn.quake.net/incoming/sns-beam.gif Now, for the moment, imagine that the "Ferro" pieces are not present. When any vertical component of an external magnetic field is applied (as from fluctuations of the Earth's magnetic field), the effect is to cause an increase in the attraction of the two magnets. Forget that they are repulsing, and just think of them as ferromagnetic. Their permeability will concentrate some of the vertical field applied and cause the pieces to at- tract. This will happen even though the magnets are generally repulsing each other. The effect will be very small, but direct- ly proportional, and in addition to the overall magnet field. Now assume that the beam is ferromagnetic and thick enough that it does not saturate, but instead acts as a keeper, sending the flux back to the lower side magnets. If the upper ferro pieces are added, and have a similar permeability to the lower pieces, when a vertical component of an external uniform field (essen- tially the definition of flux from the Earth's field) is applied, then we have just balanced the attractive forces top and bottom for this external field and there will be no disturbance to the beam position. Obviously, this doesn't fix the temperature sensitivity of the magnets. But probably temperature control is easier than the problem of low level magnetic shielding. Anyway, just a thought. Charles R. Patton, Editor, Geo-Monitor patton@......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: piezoelectric instruments Date: Tue, 09 Dec 1997 00:32:49 -0700 (MST) Hello All, I was talking with a fellow today about different recording techniques and what it would take to make different types when we began discussing the use of piezoelectric transducers arrayed in a solid box around a solid block (mass). I was pretty certain that the kind of data recieved in terms of voltage was essentially a measure of force which is proportional to acceleration (the resistance of the mass to acceleration would produce an opposite inertial force which would then create a pressure on the piezoelectric crystal, and the displacement of the crystal is proportional to the force which is proportional to the potential created). He insisted that it actually measured displacement but I was unable to see how this was so (there was a slight language barrier). If anybody who is familiar with these kinds of designs could e-mail a reply about this I would greatly appreciate it as I would like to experiment with this kind of instrument in the future. Also, if anybody knows how much these kinds of transducers cost I would also be grateful... ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Richard A. Webb" Subject: Re: WWV Antenna Date: Tue, 09 Dec 1997 07:20:48 -0500 I'm sure that there was no pun intended. Dick At 07:59 PM 12/07/97 -0500, you wrote: >Just to add one more input on the WWV antenna topic. I have a dedicated >WWV receiver in NH. The antenna was a 30 ft. long wire going from my >chimney to a nearby tree. About 4 years ago the insulator at the far >end of the wire broke leaving the antenna dangling down the chimney. >Someday I'll put the thing back up but it remains adequate. > >This all to support the approach of try the simplest thing before going >to any great lengths. > >Steve Hansen > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: Magnetic spring seismometer improvement? Date: Tue, 9 Dec 1997 07:38:28 -0600 I wonder if this is what happens or does the earth's field simply attract or repel the moveable magent? If this is the case one could reduce the problem by using two pairs of magnets with the fields going in opposite directions. The earth's field would attract one magnet and repel the other cancelling out the effect. Jim Hannon patton@......... on 12/08/97 11:44:55 PM Please respond to psn-l@............. To: psn-l@.............. cc: RCBAKER@......... (bcc: James M Hannon/CedarRapids/Collins/Rockwell) Subject: Magnetic spring seismometer improvement? Roger (Baker), I have been pondering the problem of shielding a magnetic spring per your beam/repulse magnet seismometer, and think I may have a solution. I posted a GIF file on Larry's site at: ftp://psn.quake.net/incoming/sns-beam.gif Now, for the moment, imagine that the "Ferro" pieces are not present. When any vertical component of an external magnetic field is applied (as from fluctuations of the Earth's magnetic field), the effect is to cause an increase in the attraction of the two magnets. Forget that they are repulsing, and just think of them as ferromagnetic. Their permeability will concentrate some of the vertical field applied and cause the pieces to at- tract. This will happen even though the magnets are generally repulsing each other. The effect will be very small, but direct- ly proportional, and in addition to the overall magnet field. Now assume that the beam is ferromagnetic and thick enough that it does not saturate, but instead acts as a keeper, sending the flux back to the lower side magnets. If the upper ferro pieces are added, and have a similar permeability to the lower pieces, when a vertical component of an external uniform field (essen- tially the definition of flux from the Earth's field) is applied, then we have just balanced the attractive forces top and bottom for this external field and there will be no disturbance to the beam position. Obviously, this doesn't fix the temperature sensitivity of the magnets. But probably temperature control is easier than the problem of low level magnetic shielding. Anyway, just a thought. Charles R. Patton, Editor, Geo-Monitor patton@......... _____________________________________________________________________ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roger Baker Subject: Re: Magnetic spring seismometer improvement? Date: Tue, 09 Dec 1997 10:21:58 -0600 OK friends, let me explain at least some initial results of my personal experimentation in regard to magnetic suspensions. In the development of long period seismometers with good vertical sensitivity, you need to accurately balance the force of gravity with some other vertical force such as a spring or magnetism-- a problem which a Lehman circumvents as a type of pendulum. My thinking is that the setpoint of the Lehman tends to drift around, but that the forgiving nature of a magnet and coil detector in only being sensitive to velocity nicely circumvents this problem. Lets choose a magnetic suspension for a vertical instrument. In the case of magnetism, part of the problem is that you don't want the instrument to be very sensitive to exterior magnetic disturbances. As a practical matter, my best arrangement at this point is to use a single edged razor blade attracted to a thin sheet brass pivot support with rare earch magnets behind it to pull the blade into gentle contact to the brass. My solution to making the arrangement insensitive to magnetic fluctuation is to use two ounces of lead fishing weights on the blade and then two little Radio Shack rare earth magnets acting in repulsion to support the whole two ounces. My thinking is that the magnetic field used for suspension is now so great that the relative significance of the earth field will be highly diluted as a variable. I do use a third rare earth magnet on a screw support from above to fine tune the vertical position of the beam which carries a flag to interrupt a photobeam displacement sensor, however. The basic situation is still that two relatively small and powerful magnets in repulsion provide all the force to support several ounces of weights on a very short beam. That part is done. Force feedback will now require a very small coil with lots of fine turns, resembling an aspirin tablet inserted in the gap between the two magnets. I haven't done that part yet, but do have a force feedback circuit that worked pretty well with a previous version. The whole must be well maintained at some constant temperature, but this is not hard to do as posted earlier. Aditionally, I reread the Streckeisen paper cited a week or two back,and got convinced that atmospheric buoyancy is a serious problem that can be easily cured by mounting the instrument in any sort of rigid airtight enclosure. My preference is to cut off the top of a gallon jug and mount this over a plate of glass supporting the instrument. the leads could all be led out the stopper and a seal maintained under very mild vacuum. The Streckeisen (can't remember coauthor W's name)paper has a very interesting discussion of the importance of Q as a design consideration. Q is good and magnetic suspensions have high Qs. They also used a differential transformer as a DC displacement transducer, but an LED and phototransistor combination seems a lot easier to set up from my point of view with probably comparable sensitivity and has absolutely no backforce unlike a differential transformer and even capacitance. The heavy artillery in terms of high displacement sensitivity is capacitance micrometry, but that is difficult to set up too. --Yours, Roger Baker _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: shansen@........ (shansen) Subject: Re: WWV Antenna Date: Tue, 9 Dec 1997 13:27:44 -0500 (EST) Dick Webb wrote: >I'm sure that there was no pun intended. > >Dick > Guess I wasn't too subtle. Steve >At 07:59 PM 12/07/97 -0500, you wrote: >>Just to add one more input on the WWV antenna topic. I have a dedicated >>WWV receiver in NH. The antenna was a 30 ft. long wire going from my >>chimney to a nearby tree. About 4 years ago the insulator at the far >>end of the wire broke leaving the antenna dangling down the chimney. >>Someday I'll put the thing back up but it remains adequate. >> >>This all to support the approach of try the simplest thing before going >>to any great lengths. >> >>Steve Hansen >> >> >> >>_____________________________________________________________________ >> >>Public Seismic Network Mailing List (PSN-L) >> >>To leave this list email listserver@............. with the body of the >>message: leave PSN-L >> > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: piezoelectric instruments Date: Tue, 09 Dec 1997 08:32:46 -0800 John- Not to long ago I made a cube(about 6" on a side) of 1/4" thick acrylic plastic. I installed a peizo disk(used for speakers)on each face in a cut hole in the side.I then filled the cube with mineral oil. I then ran opposite sides outputs into a differencing amp. Opposite sides would record opposite signs when the mass moved.Thus forming a three component sensor. From what I know about peizos is that their voltage output is a function of velocity and respond better to higher frequencies. I couldn't get the system to respond the way I had hoped. I think my problem was that I didn't have the gain high enough an the frequency cutoff low enough. I think there is promise in the concept. I also made a one direction sensor in a similar design. I used a acrylic tube (about 2 1/2" in diameter) suspended a steel rod in the center between two Radio Shack peizo disks. Each disk formed the end of the tube.I could turn the tube on end then the other end and see how 2G affected the response. The output would go to zero when at rest (ie velocity). I think with proper amplification the system would work well.I am not sure about how to impose damping to the system. What I am trying to do now is find peizo cubes that I could use in a shake table. The disks are to weak to push the table mass + sensor. The beauty of peizo mat'l is that one can get small controlled displacements from an electronic source w/o a D/A converter etc. I was thinking of a spark generating peizo mat'l for a source.I have seen peizo transducers in Motion or Sensor magazines but I have to go back and find the company's name. Let me know what you find out. I hope this helps. Barry John Hernlund wrote: > > Hello All, > I was talking with a fellow today about different recording techniques > and what it would take to make different types when we began discussing > the use of piezoelectric transducers arrayed in a solid box around a > solid block (mass). I was pretty certain that the kind of data recieved > in terms of voltage was essentially a measure of force which is > proportional to acceleration (the resistance of the mass to > acceleration would produce an opposite inertial force which would then > create a pressure on the piezoelectric crystal, and the displacement of the > crystal is proportional to the force which is proportional to the > potential created). He insisted that it actually measured displacement > but I was unable to see how this was so (there was a slight language > barrier). If anybody who is familiar with these kinds of designs could > e-mail a reply about this I would greatly appreciate it as I would like > to experiment with this kind of instrument in the future. Also, if > anybody knows how much these kinds of transducers cost I would also be > grateful... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: piezoelectric instruments Date: Wed, 10 Dec 1997 00:29:19 -0700 (MST) On Tue, 9 Dec 1997, barry lotz wrote: > John- > tube.I could turn the tube on end then the other end and see how 2G > affected the response. The output would go to zero when at rest (ie > velocity). I think with proper amplification the system would work > well.I am not sure about how to impose damping to the system. Maybe it went to zero because the recording of the signal helped to discharge the sensor??? I have been thinking more on this. I remember a demonstration of piezoelectricity in my mineralogy class when a nice tourmaline crystal was dipped into liquid nitrogen, allowed to cool, and then pulled out. Since the coefficient of thermal expansion for tourmaline is anisotropic the difference in lengths produced an electric field. Ice began to condense on the crystal from each end in the shape of a dipole field and remained until it melted. For this reason I think it is the relative displacement of different crystallographic directions in piezoelectric crystal that causes charge to migrate toward each end (on 001 directions in hexagonal or tetragonal crystals). In a mass/crystal system the relative displacement will be proportional to the restoring force applied to it according to Hooke's Law F = -kx where k represents the compressional modulus for that crystallographic direction. Adding the forces yields MA = -kx + ma, where ma is the force supplied by the inertial mass and it equals MA because the system itself responds to the force applied to the seismometer due to the seismic event which accelerates it. What this means is that when MA = 0, ma = kx or x = a(m/k) = CV where C would be a piezoelectric constant and V is the potential created in volts. My reasoning for the CV term is that piezoelectricity is caused by displacement in a crystal and that the charge is proportional to the displacement and therefore to the potential... Is this sound reasoning? Or did I forget my physics already? ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Al Allworth Subject: Re: piezoelectric instruments Date: Wed, 10 Dec 1997 01:20:51 -0800 (PST) At 08:32 AM 12/9/97 -0800, you wrote: >John- In considering what piezo devices can do as transducers one must keep in mind that they are capacitors. as capacitors their response will be dictated by the resistive load placed upon them. I think if a high capacitance device like a spark generator was connected to an extremely high input resistance amp (electrometer) the low frequency response might be good enough. The remaining problems would still be the stiffness of the device and sensitvity to tempurature and humidity for some materials. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: USGS presentation about the status of Mammoth Lakes Date: Wed, 10 Dec 1997 16:59:21 -0700 PSN- I am at Larry's to work on the PSN presentation this Friday at the AGU meeting, and I have just returned from an excellent presentation at AGU by Dave Hill, USGS, about the current status of the seismic unrest at Mammoth Lakes. He reviewed the history of seismic activity and uplift of the resurgent dome at Long Valley Caldera near Mammoth Lakes during the last century. He also compared the Long Valley uplift to the uplift of other large calderas, and he noted that the Long Valley uplift rate is significantly less than the uplift rate of some other large calderas, such as Rabaul, prior to their eruption. He said that the seismic activity of the last month has been at times close to the threshold when a yellow alert status would be have been declared, but the activity has somewhat quieted down recently. He also noted that the four magnitude 6+ earthquakes that took place in 1980 were not accompanied by an eruption and that the uplift during period, though not then regularly monitored, must have been greater than current rates. Overall, I have the feeling that the USGS is doing a thorough and conscientious job of monitoring the seismic unrest of Long Valley Caldera and that the USGS will provide timely and reliable hazard assessments. -Edward _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: piezoelectric instruments Date: Wed, 10 Dec 1997 08:46:42 -0800 John Experiment time! I just fed the peizo disk output into the noninverting input of a FET op amp(high input resistance). You were right. I got 2 volts for a 1G load on the particular mass I was using. I guess what I thought was change in rate of displacement(velocity) was capacitor leakage/discharge through the load resistor. Barry John Hernlund wrote: > > On Tue, 9 Dec 1997, barry lotz wrote: > > John- > > tube.I could turn the tube on end then the other end and see how 2G > > affected the response. The output would go to zero when at rest (ie > > velocity). I think with proper amplification the system would work > > well.I am not sure about how to impose damping to the system. > > Maybe it went to zero because the recording of the signal helped to > discharge the sensor??? > > I have been thinking more on this. I remember a demonstration of > piezoelectricity in my mineralogy class when a nice tourmaline crystal > was dipped into liquid nitrogen, allowed to cool, and then pulled out. > Since the coefficient of thermal expansion for tourmaline is anisotropic > the difference in lengths produced an electric field. Ice began to > condense on the crystal from each end in the shape of a dipole field and > remained until it melted. For this reason I think it is the relative > displacement of different crystallographic directions in piezoelectric > crystal that causes charge to migrate toward each end (on 001 directions > in hexagonal or tetragonal crystals). In a mass/crystal system the > relative displacement will be proportional to the restoring force applied > to it according to Hooke's Law F = -kx where k represents the compressional > modulus for that crystallographic direction. Adding the forces yields > MA = -kx + ma, where ma is the force supplied by the inertial mass and it > equals MA because the system itself responds to the force applied to the > seismometer due to the seismic event which accelerates it. What this > means is that when MA = 0, ma = kx or x = a(m/k) = CV where C would be a > piezoelectric constant and V is the potential created in volts. My > reasoning for the CV term is that piezoelectricity is caused by > displacement in a crystal and that the charge is proportional to the > displacement and therefore to the potential... > > Is this sound reasoning? Or did I forget my physics already? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: An Excursion to Long Valley caldera Date: Wed, 10 Dec 1997 23:23:47 -0700 As a geologic consultant to the Reno Gazette Journal for an upcoming newspaper report, I just returned from a field trip to the Mammoth Lakes, Long Valley caldera area. Despite the 2-3 feet of recent snow fall and -2 degree F temperatures, we toured many of the popular geologic locations, like the Hilton Creek fault, Hot Creek Hot Springs, the geothermal power plant, Inyo-Mono Craters, and the infamous Mammoth Mountain. We also interviwed many people in town. A bright blue sky, still winds, and a 4x4 - a perfect day for a cruise about. A couple things were outstanding: 1) There were a lot more dead tree locations than described in Chris Farrar's paper. Interestingly, it was not hard to locate them as there seemed to be thermal anomalies associated with dead trees zones and the snow had already melted off, quite striking since there was 2-3 feet of snow in most other places. These locations are near the geothermal power plant and in the Hot Creek area, all along the south boundary to the resurgent dome. 2) Standing at the Hot Creek Fish Hatchery which is near the center of the caldera and with a 250 degree panorama of the caldera rim, I was amazed at the size of the caldera. It is moving to imagine the whole caldera performing one huge strombolian eruption! ...to look at the resurgent dome and get a feeling for up much uplift had occurred since the last rhyolite flow or even the past few weeks...to look at Mammoth Mountain from 8 miles away and imagine it spouting a 30,000 ft. column of ash...Stunning! 3) There was a broad denial from many of the residents to the situation at hand. The Gazette Journal interviewed many “man on the street” and it was far too common for people to say, “oh, another quake" or "yeah, I felt it” or “Excuse me, I have to go back to work” or "no comment". Many would probably like to see the whole situation go away. One said, “well, if I gotta go, this is a beautiful place to leave the planet.” (At that moment, I remember the care taker of Spirit Lake Lodge at the base of Mt. St. Helens who refused to leave for similar reasons.) Yet, given the day and the outstanding skiing conditions, I couldn't blame her. 4) Just how big the Inyo-Mono Craters chain of extrusions really are. Many reports call them small eruptions. I beg to differ. And to imagine some of them going off just 500 years ago! Clearly moving to this geologist’s soul! We ended up at the North Crater near Mono Lake. Beautiful obsidian glass. But more spectacular was the mirror reflection of Mono Lake on that windless and cloudless day. We drove to the South Tufa location and took the small nature trail trail to the shore where there was a stillness to the water I had never seen before. And in the fading sunlight of the afternoon and the intense quiescence of the area, there was a serenity which was thoroughly captivating. A brief note: we found a freshwater upwhelling at shoreline near some spires which was moderately warm, perhaps giving clues to its possible thermal origins. Abundant fresh calcium carbonate (and aragonite?) rinds and crystals, growing new a new generation of tufa spires. 5) A greater potential for earthquake-induced avalanches. I think this could be a potential hazard during winter months and should be looked into further. While we were there, a M3.7 temblor occurred. I didn’t feel the quake. I was eating dinner at the Chart House when it happened at 9:12 pm. There was a Lyons Club meeting going on at the other side of the building and they were making quite the racket. But, as a reference, many people interviewed said they did feel the quake. Most seem to be experts to feeling them by now (perhaps like the residents of Landers and Yucca Valley, CA, eh?). They said if your are on a second story building and quite still, you can even feel the M2.2’s. (Imagine that! Then imagine trying to sleep the night of Nov 22 or Nov 30 in a loft when hundreds of M2+ quakes occurred..Eeek!) Interestingly, there was a lot more damage from the M4.5, M4.7 and M4.8 events on Nov 22 and the Nov 30 M4.9 quake than previously reported. Many items toppled from table and shelves, including pictures, nick-nacks, etc. Some stores experienced some damage to commercial items. Some pictures fell from walls. Also, it seems as though some person in town sells painted old tree cutting saw blades and many of these fell from the walls. One person said she had to duck to keep from getting hit by one from the Nov 30 jolt. One more item to the Jim Berkland fans. Pet owners in the area are having difficulties. The animals are doing weird things,dogs are incessantly barking and howling, cat are clawing the heck out of furniture, and birds are squawking and flying about their cages. One person we talked to correlated the animal behavior with the earthquake activity. This should be looked into further. While I was there, I secured a weekly Seismo-Watch earthquake graphic in the Mammoth Times newspaper. I am looking for sponsors, so if any one would like to have their company acknowledged for sponsoring a valuable service to the residents and tourists of the area, please contact me. I am looking at the $25-35/week range for sponsorships with a minimum 6 month commitment. The graphic will be no doubt be heavily read and your commitment will receive a lot of attention as well. There is an obvious PR potential there. Anyway, an interesting trip. Beautiful country! Condos are as expensive as ever. -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Geo-Magnetic Field Change Detected. Date: Thu, 11 Dec 1997 00:54:45 -0800 (PST) Hello All: I monitor local geo-magnetic field strength changes as possible precursors to earthquakes activity. Yesterday (Wednesday) I registered a major change in the magnetic field strength in the area near Rancho Cucamonga/Fontana, California. Every last time I noticed this type of a fluctuation there was an event near Fontana/Rialto within a week of it that was M4-5.0 in size. My instrumentation includes a Spectrum Analyzer used to scan the 2.0-4.0 Hz range for amplitude changes around 3.0 Hz. So far this area has been acting fairly normal. Except for a 10 dB increase in signal level that occurred simultaneous to the magnetic field strength changes. So, I will be watching this data very carefully over the next few weeks. The Spectrum Analyzer has a floppy disk drive used for dumping data to diskette. There was a problem in formatting the disk, so I'm not sure if I actually captured anything yesterday except for what was in memory. This Japan manufactured instrument uses the NEC format and so it might not be compatible with DOS 720K formatting. I have a conversion program that came with it. But, it is in GW BASIC. Also, there was a major Santa Ana wind blowing thru there today. Could this possibly affect geo-magnetic field strengths? Frank Condon mail to:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Geo-Magnetic Field Change Detected. Date: Thu, 11 Dec 1997 22:32:25 +1200 Gidday Frank, your recorded change was probably the arrival of an interplanetary shockwave that originated on the sun as a Coronal Mass Ejection (CME) 2-3 days ago.... this shock has been strong enough to produce auroral conditions which have been visibly observed over large parts of Canada and Alaska despite the brightening moon phase. this from the "horses mouth" The geomagnetic field began the period at quiet levels but quickly escalated to unsettled at 10/0600UT and active conditions at 10/1200UT. Unsettled to active conditions have persisted since. This disturbance is a result of the 6 December very long duration C1 flare and associated halo/CME. STD: The arrival of the CME noted above occurred at 05:30 UTC. It was marked by a sudden magnetic impulse measuring 27 nT at Boulder. you have a good magnetometer there and over the next 5 years you are going to record many dozens of these event many very much stronger than this latest one. 27 nT is reasonably small I have seem some up to 1000nT during last solar max. Dave At 12:54 AM 12/11/97 -0800, you wrote: >Hello All: >I monitor local geo-magnetic field strength changes as possible precursors >to earthquakes activity. Yesterday (Wednesday) I registered a major change >in the magnetic field strength in the area near Rancho Cucamonga/Fontana, >California. Every last time I noticed this type of a fluctuation there was >an event near Fontana/Rialto within a week of it that was M4-5.0 in size. My >instrumentation includes a Spectrum Analyzer used to scan the 2.0-4.0 Hz >range for amplitude changes around 3.0 Hz. So far this area has been acting >fairly normal. Except for a 10 dB increase in signal level that occurred >simultaneous to the magnetic field strength changes. So, I will be watching >this data very carefully over the next few weeks. The Spectrum Analyzer has >a floppy disk drive used for dumping data to diskette. There was a problem >in formatting the disk, so I'm not sure if I actually captured anything >yesterday except for what was in memory. This Japan manufactured instrument >uses the NEC format and so it might not be compatible with DOS 720K >formatting. I have a conversion program that came with it. But, it is in GW >BASIC. Also, there was a major Santa Ana wind blowing thru there today. >Could this possibly affect geo-magnetic field strengths? > >Frank Condon >mail to:frankcnd@.......... >"Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: piezoelectric instruments Date: Thu, 11 Dec 1997 09:52:44 -0700 (MST) On Wed, 10 Dec 1997, barry lotz wrote: > John > Experiment time! I just fed the peizo disk output into the > noninverting input of a FET op amp(high input resistance). You were > right. I got 2 volts for a 1G load on the particular mass I was using. I > guess what I thought was change in rate of displacement(velocity) was > capacitor leakage/discharge through the load resistor. > Barry Thanks for trying it out! Now the thing to look at is its frequency response. If you have a working shake table maybe you could look at its magnification for various frequencies and same amplitudes. I think winquake will allows you to integrate the data twice to get displacement, though I have never tried it. Of course, the higher frequencies will yield greater acceleration, but a high sampling rate should allow for good integration (many times a low sampling rate makes for spikes and amplifies the smallest discontinuity). Although it seems doubtful, maybe you could get a lower frequency response out of it... I may try and pick up some piezoelectric transducers if this looks promising! ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: AGU abstract Date: Thu, 11 Dec 1997 12:04:24 -0700 >From: S-T Morrissey >Date: Mon, 8 Dec 1997 19:08:31 -0600 (CST) >To: "Edward Cranswick, Lakewood, CO " >Subject: AGU abstract >Cc: sean@........... > >Edward, > >I just remembered that I HAD sent a version of my AGU abstract into >here from home. You can forward it to the PSN if you want. >Of course, some details have changed since the abstract was submitted, >like reducing the operating period to 87 seconds (by simply changing >a resistor and the integrator capacitor in the feedback) because of the >noise in the basement of my house. > > >Abstract submitted for 1997 fall AGU meeting: > >A Homemade High Resolution Broadband Vertical Seismometer Constructed >from Consumer Hardware and Electronics Items for School and Personal Use. > >Sean-Thomas Morrissey (Dept. of Earth and Atmospheric Sciences, >St.Louis University, 3507 Laclede; St. Louis MO, 63103; 314 977 3129; >sean@........... > >The need for an affordable modern broadband seismometer and seismograph >system has been fulfilled by the construction of a very sensitive vertical >seismometer using only consumer hardware and electronics components, with >a digital multimeter and a PC as the digital seismograph. Key elements of >the design are a leaf-spring suspension (the blade of a drywall taping knife), >a displacement transducer with nanometer resolution (made from two miniature >audio transformers), and a very common but powerful feedback transducer >(the voice coil and magnet of a large stereo speaker). The 60 cm long >frame is of storm door aluminum; the hinges are bronze weatherstrip, >epoxied in place. The digitizer is a consumer digital multimeter with >serial output to the PC; digital seismograms are made with Mathcad. > >The broadband sensor normally operates at a "natural period" of 150 seconds >using a classical triple feedback system, which readily allows configurations >of To from 20 to 300 seconds. The velocity output is 1600 V/m/s, which the >transfer function indicates is flat from 100 seconds to 30 hz. Auxiliary >windings added to the main (speaker) coil allow for dynamic temperature >and pressure compensation of the mass position, as well as step calibration. >Without a pressure containment, the sensor readily shows atmospheric "acoustic >gravity" waves at periods greater than 10 minutes; the "mass position" output >shows earth tides. Broadband seismograms of M > 5.5 events almost anywhere >are the normal record. They compare favorably with local broadband records >from commercial sensors. > > >Regards, >Sean-Thomas > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: AGU abstract Date: Thu, 11 Dec 1997 14:18:06 -0600 You realize that this is driving me nuts, waiting for the details of this instrument! :) Jim Hannon cranswick@........ on 12/11/97 01:04:24 PM Please respond to psn-l@............. To: psn-l@............. cc: (bcc: James M Hannon/CedarRapids/Collins/Rockwell) Subject: AGU abstract >sean@........... > >The need for an affordable modern broadband seismometer and seismograph >system has been fulfilled by the construction of a very sensitive vertical >seismometer using only consumer hardware and electronics components, with >a digital multimeter and a PC as the digital seismograph. Key elements of >the design are a leaf-spring suspension (the blade of a drywall taping knife), >a displacement transducer with nanometer resolution (made from two miniature >audio transformers), and a very common but powerful feedback transducer >(the voice coil and magnet of a large stereo speaker). The 60 cm long >frame is of storm door aluminum; the hinges are bronze weatherstrip, >epoxied in place. The digitizer is a consumer digital multimeter with >serial output to the PC; digital seismograms are made with Mathcad. > >The broadband sensor normally operates at a "natural period" of 150 seconds >using a classical triple feedback system, which readily allows configurations >of To from 20 to 300 seconds. The velocity output is 1600 V/m/s, which the >transfer function indicates is flat from 100 seconds to 30 hz. Auxiliary >windings added to the main (speaker) coil allow for dynamic temperature >and pressure compensation of the mass position, as well as step calibration. >Without a pressure containment, the sensor readily shows atmospheric "acoustic >gravity" waves at periods greater than 10 minutes; the "mass position" output >shows earth tides. Broadband seismograms of M > 5.5 events almost anywhere >are the normal record. They compare favorably with local broadband records >from commercial sensors. > > >Regards, >Sean-Thomas > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Walt Williams" Subject: Ancient Mars Lake Bed & Malin reports to the AGU Date: Thu, 11 Dec 1997 12:51:22 +0000 Hello All, FYI. Walt Williams, 97.12.11 dfheli@.............. =============================================== To: "'seti@........" From: LARRY KLAES Subject: SETI Ancient lake bed found on Mars by MGS. Date sent: Tue, 9 Dec 1997 09:44:47 -0500 Send reply to: LARRY KLAES A news item from UPI reports that the Mars Global Surveyor (MGS) currently in Martian orbit has found evidence for an ancient lake on the Red Planet. This builds further evidence for a world that was much warmer and wetter, and therefore perhaps more hospitable to life. This in turn implies that if life could appear on more than one planet in our solar system, then perhaps life appeared many times over in other planetary systems, eventually leading to the kind of intelligent life we hope to detect with Project Argus. The URL is: http://biz.yahoo.com/upi/97/12/08/general_news/usmars_2.html ===================================================== To: "Walt Williams" From: LARRY KLAES Subject: re: Ancient Lake Bed & Malin reports to the AGU Date sent: Thu, 11 Dec 1997 12:11:29 -0500 Send reply to: LARRY KLAES Hello Walt, By all means, please do. Regards, Larry Klaes --------------------------------------------------------------------- From: "Walt Williams" , on 12/11/97 9:04 AM: Hello Larry Klaes, Would you mind if I were to cross post this in the Public Seismic Network (PSN) reflector list? The AGU, which is referenced by the URL in the report, is being attended and features several members of the PSN as speakers. I am sure the other members of the PSN (i.e., those of us who can not attend) would enjoy reading your find. Best Regards, Walt Williams, 97.12.11 dfheli@.............. http://www.pacificnet.net/~dfheli ============================================================ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Ancient Mars Lake Bed & Malin reports to the AGU Date: Thu, 11 Dec 1997 12:58:23 -0700 Interesting report about the Mars Global Surveyor. Anyone know where one could see a photo of the "playa" -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com Walt Williams wrote: > > Hello All, > > FYI. > > Walt Williams, 97.12.11 > dfheli@.............. > =============================================== > > To: "'seti@........" > From: LARRY KLAES > Subject: SETI Ancient lake bed found on Mars by MGS. > Date sent: Tue, 9 Dec 1997 09:44:47 -0500 > Send reply to: LARRY KLAES > > A news item from UPI reports that the Mars Global Surveyor (MGS) > currently in Martian orbit has found evidence for an ancient lake on > the Red Planet. This builds further evidence for a world that was > much warmer and wetter, and therefore perhaps more hospitable to life. > > This in turn implies that if life could appear on more than one planet > in our solar system, then perhaps life appeared many times over in > other planetary systems, eventually leading to the kind of intelligent > life we hope to detect with Project Argus. > > The URL is: > > http://biz.yahoo.com/upi/97/12/08/general_news/usmars_2.html > > ===================================================== > To: "Walt Williams" > From: LARRY KLAES > Subject: re: Ancient Lake Bed & Malin reports to the AGU Date > sent: Thu, 11 Dec 1997 12:11:29 -0500 Send reply to: LARRY > KLAES > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: An Excursion to Long Valley caldera Date: Thu, 11 Dec 1997 15:22:53 -0700 Charles- I really like your report from Mammoth Lakes. I am sorry that I missed you at AGU because you were "in the field". -Edward _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: media wakes up. Date: Thu, 11 Dec 1997 16:08:04 By Edie Lau Bee Staff Writer (Published Dec. 11, 1997) SAN FRANCISCO -- A restless earth has shaken Mammoth Mountain 8,000 times this year and counting, possibly signaling a comeing volcanic eruption, scientists said Wednesday. Speaking at an unscheduled session hastily convened during an American Geophysical Union meeting, earthquake and volcano experts said an ancient volcanic region in the eastern Sierra, south of Mono Lake, is in the midst of the most intensive seismic activity seen in a century. "It's kind of dramatic, if you look at the last year," said David Hill, a U.S. Geological Survey volcanologist based in Menlo Park. Hill is in charge of the Mammoth area for the USGS. Most of the 8,000 earthquakes, measured at magnitude 1.2 or greater, have occurred since July. The past three weeks have been especially active: On Nov. 22 alone, 944 quakes were recorded. The most powerful one of the year came on Nov. 30, measuring 4.9 on the Richter scale. As if he could forget, Hill was reminded Tuesday night of the restive region as he drove home -- his beeper went off, alerting him to a magnitude 3.7 quake shortly after 9 p.m. That was followed by more than 100 temblors. Considered individually, the quakes are not particularly big. USGS spokeswoman Pat Jorgenson said the 4.9 quake, with an epicenter about two miles from the little town of Mammoth Lakes, broke some glass. The 1989 Loma Prieta earthquake in the Bay Area, by comparison, measured 7.1. The greater concern for Mammoth is what the shuddering earth might foretell. "You can see clearly there's a reason for concern," said Peter Ward, a USGS geophysicist, "but it's not clear exactly what's going to happen." All scientists can say with confidence is that somewhere beneath the surface of the ground, molten rock is moving. The big question is whether and when it will come to the surface. History isn't much guide. Lucy Jones, a seismologist at the Geological Survey's Pasadena station, noted that Mount St. Helens was restless for only three months before blowing in 1980. The volcano that erupted on the Caribbean island of Montserrat this year rumbled for 95 years. "So you don't know," Jones said. "We could go through this (with Mammoth) for 95 years." Scientists call the volcano the Long Valley Caldera. A caldera is a large volcanic depression. This one was the product of a volcanic eruption some 760,000 years ago. Having ejected a load of hot, liquid rock -- magma -- the earth's surface sank more than one mile, forming an oval crater some 20 miles long by 10 miles wide. The caldera straddles Highway 395, beginning about 15 miles south of Mono Lake, and crossing Mammoth Mountain at its southwest edge. About 5,000 people live in the town of Mammoth Lakes inside the volcanic depression. On a big ski weekend, the population can expand by 25,000 visitors. Hill said scientists should be able to warn of an impending eruption "at least hours, and probably days, maybe weeks (in advance). Few of them really sneak up unannounced." The latest seismic activity dates to 1978, when a quake of magnitude 5.4 hit six miles southeast of the caldera. The place has shivered off and on since then. Besides the earthquake swarms, the moving underground magma is evident in a swelling hump in the middle of the caldera. Jones said the caldera floor has risen by 30 to 31 inches since 1979; and by more than 2 inches in just the past six months. Responding to intense seismic activity in the past, the Geological Survey issued a "notice of potential volcanic hazard" for the area in 1982, an act criticized by local business people fearful of losing tourists. The notice was rescinded in 1984 when the number and power of quakes diminished. The agency has a different type of warning system now. The first stage is "no immediate risk," indicating a typical situation that includes swarms of small earthquakes, along with the occasional bigger quake, measuring about magnitude 4. The current state is still within the "typical" description. But barely. Hill said that had the swarm in late November included a quake of magnitude 5, the USGS would have posted a volcano watch. The agency steps up monitoring under that condition of "intense unrest," setting up emergency field headquarters on site. It alerts the state Office of Emergency Services, which notifies local authorities. The next stage is a warning, which means that an eruption is likely within hours or days. The last stage is a volcano alert, meaning that an eruption is under way. The Long Valley Caldera is part of a large volcanic chain extending 25 miles from Mono Lake to Mammoth Mountain. Scientists believe that small eruptions happened in Mono Lake as recently as the mid-1800s. "That's the price you pay for living in the beautiful West Coast," Hill said. "It's beautiful because of all this geologic activity. Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: An Excursion to Long Valley caldera Date: Thu, 11 Dec 1997 16:56:50 -0800 Charles -- Thank you for the field trip report. As an interested and frequent visitor to the resurgent dome and mono craters area since the 1980 quakes (and a few times before), I read your report with interest. A couple of questions: Did you get into fumerole canyon or to the area of the drilling rig? If so, were there any changes in vent activity in fumerole canyon (or snow melt)? Any snow melt in the area of the drilling rig? Also, just north of the fish hatchery (~.7km, as I remember) is a fairly large (for the area) steam vent. Any changes there? Thanks again for posting the report, and keep 'em coming. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: An Excursion to Long Valley caldera Date: Thu, 11 Dec 1997 18:00:17 -0700 Hi Karl, I saw the vent north of the Fish Hatchery. It was very cold that day and the steam plume rose about 40-60 ft high. The newspaper went bananas over it. I've seen better at Lassen. I'm not familiar with Fumarole Canyon nor the drill rig. I stopped by the Mammoth-Pacific geothermal plant and walked about. Did not talk to the operators, although I would have liked to. I did not see any drill rig either. They usually stand out pretty good, too. There was quite a bit of snow and the reporters were...not eager to venture off the roads. -- ---/---- Charlie Karl Cunningham wrote: > > Charles -- > > Thank you for the field trip report. As an interested and frequent visitor > to the resurgent dome and mono craters area since the 1980 quakes (and a > few times before), I read your report with interest. > > A couple of questions: Did you get into fumerole canyon or to the area of > the drilling rig? If so, were there any changes in vent activity in > fumerole canyon (or snow melt)? Any snow melt in the area of the drilling > rig? Also, just north of the fish hatchery (~.7km, as I remember) is a > fairly large (for the area) steam vent. Any changes there? > > Thanks again for posting the report, and keep 'em coming. > > Karl Cunningham > La Mesa, CA. > PSN station #40 > karlc@....... > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: piezoelectric instruments Date: Thu, 11 Dec 1997 07:04:35 -0800 John The shake table is the next hurdle. I inquired about peizoelectric actuators but what limited data I have received to date say that low voltage actuators are prohibitably expensive due to stacking of several disks. I haven't tried a voice coil type. I'll keep in touch. Barry Thanks for trying it out! Now the thing to look at is its frequency > response. If you have a working shake table maybe you could look at its > magnification for various frequencies and same amplitudes. I > think winquake will allows you to integrate the data twice to get > displacement, though I have never tried it. Of course, the higher > frequencies will yield greater acceleration, but a high sampling rate > should allow for good integration (many times a low sampling rate makes > for spikes and amplifies the smallest discontinuity). Although it seems > doubtful, maybe you could get a lower frequency response out of it... I > may try and pick up some piezoelectric transducers if this looks > promising! _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: piezoelectric instruments--a simple starter Date: Thu, 11 Dec 1997 15:05:08 +0000 Hello piezo lovers everywhere , In October's issue of 'Electronics World', there is a cct. for a vertical seismo. (Altho' magazine is English........it used to be the old, 'Wireless World', ....I believe it is obtainable in USA etc.) Ingredients...one op-amp; one piezo gas lighter element; one plastic box; and a 6lbs. sack of sand !!! At this time of the year it may make a nice, 'stocking- filler', for a young lad just setting off down the seismic path. The bonus for this little device is that it detects low flying aircraft as well !! (microphonic tendencies ). Article is entitled, 'Fields, lines and tremors. (also covers simple magnetic detection and electric fields). Regards, Albert Noble (England). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Geo-Magnetic Field Change Detected. Date: Thu, 11 Dec 1997 21:56:12 -0800 (PST) Hello Dave: So that's what was being detected by my instrumentation. Do you know if this was an "X Class" emission? Today, the field seemed to have settled down to a near normal level. As for the readings at 3Hz there was another major shift in amplitude that occurred late this afternoon. I will have a better handle on studying the data in the morning. I'll be away until then from the location of the digital spectrum analyzer. Thanks, Frank Condon mail to:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" >Gidday Frank, > your recorded change was probably the arrival of >an interplanetary shockwave that originated on the sun as a Coronal Mass >Ejection (CME) 2-3 days ago.... this shock has been strong enough to >produce auroral conditions which have been visibly observed over large >parts of Canada and Alaska despite the brightening moon phase. > >this from the "horses mouth" > The geomagnetic field began the period at quiet levels but > quickly escalated to unsettled at 10/0600UT and active > conditions at 10/1200UT. Unsettled to active conditions have > persisted since. This disturbance is a result of the 6 December > very long duration C1 flare and associated halo/CME. > > STD: The arrival of the CME noted above occurred at 05:30 UTC. > It was marked by a sudden magnetic impulse measuring 27 nT at > Boulder. > > you have a good magnetometer there and over the next 5 years you are going >to record many dozens of these event many very much stronger than this >latest one. > 27 nT is reasonably small I have seem some up to 1000nT during last >solar max. > >Dave > > > > > > > > > > > >At 12:54 AM 12/11/97 -0800, you wrote: >>Hello All: >>I monitor local geo-magnetic field strength changes as possible precursors >>to earthquakes activity. Yesterday (Wednesday) I registered a major change >>in the magnetic field strength in the area near Rancho Cucamonga/Fontana, >>California. Every last time I noticed this type of a fluctuation there was >>an event near Fontana/Rialto within a week of it that was M4-5.0 in size. My >>instrumentation includes a Spectrum Analyzer used to scan the 2.0-4.0 Hz >>range for amplitude changes around 3.0 Hz. So far this area has been acting >>fairly normal. Except for a 10 dB increase in signal level that occurred >>simultaneous to the magnetic field strength changes. So, I will be watching >>this data very carefully over the next few weeks. The Spectrum Analyzer has >>a floppy disk drive used for dumping data to diskette. There was a problem >>in formatting the disk, so I'm not sure if I actually captured anything >>yesterday except for what was in memory. This Japan manufactured instrument >>uses the NEC format and so it might not be compatible with DOS 720K >>formatting. I have a conversion program that came with it. But, it is in GW >>BASIC. Also, there was a major Santa Ana wind blowing thru there today. >>Could this possibly affect geo-magnetic field strengths? >> >>Frank Condon >>mail to:frankcnd@.......... >>"Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" >> >> >>_____________________________________________________________________ >> >>Public Seismic Network Mailing List (PSN-L) >> >>To leave this list email listserver@............. with the body of the >>message: leave PSN-L >> >> > >Co-ordinator: >New Zealand >Public Seismic Network > Dave A. Nelson ZL4TBN > 24 Jensen St., > Green Is., Dunedin, > South Is.. New Zealand. > >http://psn.quake.net/dave/home.htm > >IF there indeed are other parallel universes... I can now rest in the >knowledge, that in at least one of them, I am filthy rich and drive a red >Ferrari > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: piezoelectric instruments Date: Fri, 12 Dec 1997 00:51:22 -0700 (MST) On Thu, 11 Dec 1997, barry lotz wrote: > John > The shake table is the next hurdle. I inquired about peizoelectric > actuators but what limited data I have received to date say that low > voltage actuators are prohibitably expensive due to stacking of several > disks. I haven't tried a voice coil type. I'll keep in touch. Barry, another thing to maybe try out is installing a large capacitor instead of a load resistor in the hope of reducing voltage drop. Capacitance could also be varied for a sort of low pass filter I think. It would also prevent discharge which would happen even under a large load resistance. ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: piezoelectric instruments Date: Fri, 12 Dec 1997 09:28:56 -0800 Peizo fans -- Many commercial accelerometers are made using piezoelectric transducers. These devices incorporate a "seismic mass" pressing on a piezoelectric crystal (quartz). They are usually preloaded to achieve bipolar response with only one crystal (triaxial with three). Endevco makes a number of them (see http://www.endevco.com ). The usual instrumentation for these devices is a "charge amplifier", which can be modeled by a low-pumpout-current op-amp with capacitive feedback. I've never built one of these before, but here's what I'd try... You need resistive feedback in parallel with the feedback capacitor to keep the op-amp from drifting off: (Excuse the crude ascii) C1 +-------||-------+ | | | | +-----R1-+-R3----+ | | | | R2 | | | | | --- | | \ / | | V | | | | |\ | --------+-----|- \ | | | \ | | | >----+------O Output | | / piezo --- ----|+ / --- | |/ | --- | \ / --- V \ / V This circuit converts the CHARGE from the piezo device into a voltage at its output. The main challenge is selecting the op-amp, but these days there are very some good ones. Look for ones with fet inputs and bias currents in the low picoamp region. Sometimes these are classified as electrometer amplifiers. The value of R1 is high -- 22Meg or more. Make R3 10K and R2 100 ohms to start out with. This establishes the amount of dc feedback to keep the op-amp on scale. The op-amp will probably need a zero control and may drift with temperature. C1 is small -- use perhaps 47pF or so. Make C1 larger to limit gain. Make sure the connection between the piezoelectric device and the amplifier is short -- the currents are small and noise sources abound. But be careful of shielded cable as triboelectric noise from the wiring can be a problem. The best method is to use very short open-air solid wire connections. Let me know if anyone tries this -- I'm curious how well it might work. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: piezoelectric instruments Date: Fri, 12 Dec 1997 15:09:59 -0800 On 8/18/97 I discussed briefly the equation for piezoelectric frequency response, but I thought I would expand the explanation a bit. +-----------+ | |\ | +--|- \ | | >---+---out +-----+-----|+ / | | |/ --- \ --- / |Csns \ Rin | / | | ___ ____ _ / / / ___ _ Sig1 | | ____ / / / In the figure above the piezoeletric element is represented by the equivalent C1/Sig1 combination. All piezoelectric sensors basically conform to this model in the range of interest for physical shock and vibration sensing. If you were interested in piezoelectic material for frequency control such as in oscillator crystals, the model would include a series resistance and inductance. Now as Karl just observed, you need a resistor for bias stability. Also the amplifier has an input resistance. Both can be lumped in Rin. Looking at the diagram above, you will see a voltage divider formed by Csns and Rin. The 3 dB low frequency rolloff point of that divider is figured by: f = 1 / (2*3.1416*Rin*Csns) This equation tells you that lowering the input impedance only raises the lo freq point. So loading is bad. More capacitance in the the sensor is better. The only problem with this arrangement is that it doesn't have any gain. So now we change to a charge amp. The trick with a charge amp is that the opamp now gets used in the inverting mode, so the junction of Rin and Csns goes to the negative input and the feedback comes by means of a capacitor. (Borrowing Karl's diagram below) C1 +-------||-------+ | | | | +-----R1-+-R3----+ | | | | R2 | | | | | --- | | \ / | | V | | | | |\ | --------+-----|- \ | | | \ | | | >----+------O Output | | / piezo --- ----|+ / --- | |/ Csns | --- | \ / --- V \ / V Now the opamp wants zero volts (a simplification, but go with me!) on the negative input so that means that if a voltage starts to appear on the terminal the output will move in the opposite direction trying to balance that point to zero. If the output is coupled through a capacitor, then the gain becomes the ratio of the capacitors Csns/C1. This equation is balanced at all frequencies, so it is flat at all frequencies. Since Rin has become R1 in the circuit above, it is in parallel with a "virtual ground" at the opamp input and it becomes insignificant in the equation. The last problem is to bias the amp now since you need some DC feed back. That is what R2 and R3 are supposed to do. They work because the apparent feedback resitance is very high. The R1, R2, R3 combination is a way to get the equivalent of very high resistances without the use of a very high resistors. The down side is that the bias point can become unstable due to the bias currents in the input. Sometimes the technique is to use a large capacitor for R2. Then at DC, the feedback is unity and very stable for bias, but at higher frequencies the capacitor will become low impedance and the feed back will decrease becoming dominated by the capacitor C1, and at that point the gain is as stated before, Csns/C1. Requirements for the opamp are very high input impedance (low bias current, and reasonable noise figures. Charles R. Patton, Editor, Geo-Monitor patton@......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: piezoelectric instruments Date: Fri, 12 Dec 1997 08:54:47 -0800 Karl I haven't tried your circuit yet but isn't the op amp inverted input a virtual ground? Would this ground the peizo? I inputed the peizo into the + input with a 30meg resistor to ground. The output was low & high pass filtered to eliminate dc offset and frequencies above 20-30hz. It worked pretty well. I needed the 30meg resistor to ground at the + input due to charge buildup. I'll try your circuit now. Barry Karl Cunningham wrote: > > Peizo fans -- > > Many commercial accelerometers are made using piezoelectric transducers. > These devices incorporate a "seismic mass" pressing on a piezoelectric > crystal (quartz). They are usually preloaded to achieve bipolar response > with only one crystal (triaxial with three). Endevco makes a number of > them (see http://www.endevco.com ). The usual instrumentation for these > devices is a "charge amplifier", which can be modeled by a > low-pumpout-current op-amp with capacitive feedback. I've never built one > of these before, but here's what I'd try... You need resistive feedback in > parallel with the feedback capacitor to keep the op-amp from drifting off: > (Excuse the crude ascii) > > C1 > +-------||-------+ > | | > | | > +-----R1-+-R3----+ > | | | > | R2 | > | | | > | --- | > | \ / | > | V | > | | > | |\ | > --------+-----|- \ | > | | \ | > | | >----+------O Output > | | / > piezo --- ----|+ / > --- | |/ > | --- > | \ / > --- V > \ / > V > > This circuit converts the CHARGE from the piezo device into a voltage at > its output. The main challenge is selecting the op-amp, but these days > there are very some good ones. Look for ones with fet inputs and bias > currents in the low picoamp region. Sometimes these are classified as > electrometer amplifiers. The value of R1 is high -- 22Meg or more. Make > R3 10K and R2 100 ohms to start out with. This establishes the amount of > dc feedback to keep the op-amp on scale. The op-amp will probably need a > zero control and may drift with temperature. C1 is small -- use perhaps > 47pF or so. Make C1 larger to limit gain. Make sure the connection > between the piezoelectric device and the amplifier is short -- the currents > are small and noise sources abound. But be careful of shielded cable as > triboelectric noise from the wiring can be a problem. The best method is > to use very short open-air solid wire connections. > > Let me know if anyone tries this -- I'm curious how well it might work. > > Karl Cunningham _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: bob ogburn Subject: Re: piezoelectric instruments Date: Fri, 12 Dec 1997 21:35:35 -0800 Barry, Piezoelectric devices act as a charge source, so yes, the input looks like ground. Think of the piezo device as a current source with a very high source impedance. A good description of a charge amplifier is found at the National Semiconductor web site in Application note AN-301 (http://www.national.com/apnotes/). barry lotz wrote: > > Karl > I haven't tried your circuit yet but isn't the op amp inverted input > a virtual ground? Would this ground the peizo? I inputed the peizo into > the + input with a 30meg resistor to ground. The output was low & high > pass filtered to eliminate dc offset and frequencies above 20-30hz. It > worked pretty well. I needed the 30meg resistor to ground at the + input > due to charge buildup. I'll try your circuit now. > Barry > > > Karl Cunningham wrote: > > > > Peizo fans -- > > > > Many commercial accelerometers are made using piezoelectric transducers. > > These devices incorporate a "seismic mass" pressing on a piezoelectric > > crystal (quartz). They are usually preloaded to achieve bipolar response > > with only one crystal (triaxial with three). Endevco makes a number of > > them (see http://www.endevco.com ). The usual instrumentation for these > > devices is a "charge amplifier", which can be modeled by a > > low-pumpout-current op-amp with capacitive feedback. I've never built one > > of these before, but here's what I'd try... You need resistive feedback in > > parallel with the feedback capacitor to keep the op-amp from drifting off: > > (Excuse the crude ascii) > > > > C1 > > +-------||-------+ > > | | > > | | > > +-----R1-+-R3----+ > > | | | > > | R2 | > > | | | > > | --- | > > | \ / | > > | V | > > | | > > | |\ | > > --------+-----|- \ | > > | | \ | > > | | >----+------O Output > > | | / > > piezo --- ----|+ / > > --- | |/ > > | --- > > | \ / > > --- V > > \ / > > V > > > > This circuit converts the CHARGE from the piezo device into a voltage at > > its output. The main challenge is selecting the op-amp, but these days > > there are very some good ones. Look for ones with fet inputs and bias > > currents in the low picoamp region. Sometimes these are classified as > > electrometer amplifiers. The value of R1 is high -- 22Meg or more. Make > > R3 10K and R2 100 ohms to start out with. This establishes the amount of > > dc feedback to keep the op-amp on scale. The op-amp will probably need a > > zero control and may drift with temperature. C1 is small -- use perhaps > > 47pF or so. Make C1 larger to limit gain. Make sure the connection > > between the piezoelectric device and the amplifier is short -- the currents > > are small and noise sources abound. But be careful of shielded cable as > > triboelectric noise from the wiring can be a problem. The best method is > > to use very short open-air solid wire connections. > > > > Let me know if anyone tries this -- I'm curious how well it might work. > > > > Karl Cunningham > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: Ancient Mars Lake Bed & Malin reports to the AGU Date: Sat, 13 Dec 1997 00:13:19 -0700 (MST) Try these: http://mars.sgi.com/mgs/msss/camera/images/11_10_97_release/1303/1303_2.jpg http://mars.sgi.com/mgs/msss/camera/images/11_10_97_release/2306/2306_ctx.jpg http://mars.sgi.com/mgs/msss/camera/images/11_10_97_release/2802/2802_1.jpg All of these are basins, but none of them appear to be enclosed... The third is really interesting though... ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: piezoelectric instruments Date: Sat, 13 Dec 1997 11:00:00 -0800 Barry -- Just to add a little to what Bob Ogburn wrote.. Yes the circuit shorts the output of the peizo, but it can still transfer current (charge) into the capacitor in the feedback of the op-amp. Since Q=CV, that charge will result in a voltage across the feedback capacitor, which will be presented at the output. -- Karl _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: piezoelectric instruments Date: Sat, 13 Dec 1997 00:33:14 -0800 Karl I tried your circuit last night. It's very sensitive! I had to increase the feedback cap to >1000pf . It was on my workbench which is noisy. The only problem I am having is with the predominate 60 hz signal. I am using solid wire from the peizo sensor to the solderless breadboard (about 3" away). I would like to reduce this noise at the start but I guess I could keep the initial gain lower and filter it then increase the gain more. The circuit did need a trim zero adjustment to the + input. I'll try it outside and see how the sensor works, more distant from electrical and mechanical noise. Barry Karl Cunningham wrote: > > Barry -- > > Just to add a little to what Bob Ogburn wrote.. > > Yes the circuit shorts the output of the peizo, but it can still transfer > current (charge) into the capacitor in the feedback of the op-amp. Since > Q=CV, that charge will result in a voltage across the feedback capacitor, > which will be presented at the output. > > -- Karl > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: AGU abstract Date: Sat, 13 Dec 1997 20:34:52 -0500 Sean-Thomas, I'm sure that many of us on the PSN would love to see the details of yo= ur system esp. since it is a vertical. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: piezoelectric instruments Date: Sun, 14 Dec 1997 17:26:15 -0800 Barry Glad to hear it works! You can filter the 60Hz downstream, or you could try enclosing the whole thing in a metal box connected to the signal ground. Sometimes just placing the whole thing on top of a plate of metal tied to signal ground makes quite a difference. Also, you might try connecting your signal ground to the power ground. -- Karl At 12:33 AM 12/13/97 -0800, you wrote: >Karl > I tried your circuit last night. It's very sensitive! I had to >increase the feedback cap to >1000pf . It was on my workbench which is >noisy. The only problem I am having is with the predominate 60 hz >signal. I am using solid wire from the peizo sensor to the solderless >breadboard (about 3" away). I would like to reduce this noise at the >start but I guess I could keep the initial gain lower and filter it then >increase the gain more. The circuit did need a trim zero adjustment to >the + input. I'll try it outside and see how the sensor works, more >distant from electrical and mechanical noise. > > Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Large Meteorite Impact in Iceland Date: Sun, 14 Dec 1997 18:51:34 -0800 (PST) Hello All: Did anyone pick up a seismographic signal from the recent large meteorite impact in Iceland? If so, then how does it compare to a normal tectonic earthquake seismographic waveform? Thanks, Frank Condon "mail to: frankcnd@.........." "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: BZIMMERMAN@............ Subject: Re: Large Meteorite Impact in Iceland Date: Mon, 15 Dec 1997 09:12:00 -0500 (EST) What was the date and time of the impact in Iceland? Brian Zimmerman _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Re: Large Meteorite Impact in Iceland Date: Mon, 15 Dec 1997 07:23:30 At 06:51 PM 12/14/97 -0800, you wrote: >Hello All: >Did anyone pick up a seismographic signal from the recent large meteorite >impact in Iceland? If so, then how does it compare to a normal tectonic >earthquake seismographic waveform? > I would think it would look like a surface explosion which I have a pix of using fftdsp. I don't know where the sensor is located that recorded this event though. I also recorded a large surface event just this week but did not correlate the greenland metior with that. I record forward scatter meteor echos and two channels of remote quake sensors and as I recall they were not related. The bang as I call it are just one large pulse with very little long period data and very short, short period data. I think a sonic boom would look the same. Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Marnie Gannon Subject: LA Times article on Mammoth and threat to LA water Date: Mon, 15 Dec 1997 09:19:44 -0700 Found an excellent article on Mammoth's importance to LA water: hint..two thirds of LA water supply comes from or winds through the area and DWP is launching a study on what to do..if... http://www.latimes.com/HOME/NEWS/FRONT/t000113474.html Marnie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Ega with sdr. Date: Mon, 15 Dec 1997 11:43:56 Well the lehman cought the 3.1 at mmh now I need to get a machine built up to run sdr. will my old ega monitor in the garage support sdr or emon. Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Ega with sdr. Date: Tue, 16 Dec 1997 08:37:43 +1200 Norm, I found that SDR would not work on EGA my friend north of my had to get a VGA (minimum) monitor be warned you may have troubles!!! Dave At 11:43 AM 12/15/97, you wrote: > Well the lehman cought the 3.1 at mmh now I need to get a machine built up >to run sdr. will my old ega monitor in the garage support sdr or emon. > > >Norman Davis WB6SHI >Email normd@............. >Shingle Springs, Ca, USA it ain't local... > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Computer advise... Date: Mon, 15 Dec 1997 18:38:34 -0700 >Date: Sun, 14 Dec 1997 15:24:08 -0500 >From: Robert L Barns <75612.2635@..............> >Subject: Computer advise >To: Larry Cochrane > >Larry, > Here's some good advice about computers. >If you think it's worth the time, send it to the members. > Happy holidays! >Bob Barns > If Dr. Seuss were a Technical Writer... Here's an easy game to play. Here's an easy thing to say. If a packet hits a pocket on a socket on a port, And the bus is interrupted as a very last resort, And the address of the memory makes your floppy disk abort, Then the socket packet pocket has an error to report! If your cursor finds a menu item followed by a dash, And the double-clicking icon puts your window in the trash, And your data is corrupted 'cause the index doesn't hash, Then your situation's hopless and your system's gonna crash! You can't say this? What a shame, sir! We'll find you another game, sir! If the label on the cable on the table at your house Says the network is connected to the button on the mouse, But your packets want to tunnel on another protocol That's repeatedly rejected by the printer down the hall And your screen is all distorted by the side effects of Gauss So your icons in the windows are as wavy as a souse, Then you may as well reboot and go out with a bang, 'Cause as sure a I'm a poet, the sucker's gonna hang! When the copy of your floppy's getting sloppy on the disk, And the microcode instructions cause unnecessary RISC, Then you have to flash your memory and you'll want to RAM your ROM Quickly turn off the computer and be sure to tell your mom! Author unknown. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Re: LA Times article on Mammoth and threat to LA water Date: Mon, 15 Dec 1997 11:51:19 >hint..two thirds of LA water supply comes from or winds through the area >and DWP is launching a study on what to do..if... yep, and a long history of unrest (political) in the owens valley over that issue. The folks from LA water and power were not very welcome up there. Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Recent event Date: Tue, 16 Dec 1997 07:10:26 -0800 Hi all I picked up some pretty strong surface waves at around 12:00 UTC. I can't get through to NEIS. Any one pick up them? Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: peaches@............ (Donna Whitaker) Subject: Re: Recent event Date: Tue, 16 Dec 1997 16:52:16 -1000 (HST) Hi Barry. Its prob the Mexico event. 97/12/16 11:48:33 16.27N 98.74W 33.0 5.4Ms A NEAR COAST OF GUERRERO, MEXICO Tony >Hi all > I picked up some pretty strong surface waves at around 12:00 UTC. I >can't get through to NEIS. Any one pick up them? > Barry > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: LA Times article on Mammoth and threat to LA water Date: Wed, 17 Dec 1997 08:13:53 -0700 BTW: this gentleman wrote a paper in the early 1990's on the effect of a volcanic eruption at Long Valley caldera on LA's water supply: R. Forrest Hopson, M.S. Geologist 6597 Camino Venturoso Goleta, CA 93117 USA (805) 964-5041 mailto:forrest@................... -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Large Meteorite Impact in Greenland Date: Wed, 17 Dec 1997 17:52:45 -0800 (PST) Hi Norman: It would be postulating... But, I wonder who is the most prominent geologist that specializes in meteorites? Also, I wonder if they were unable to attend the recent AGU meeting on account of they were out looking for a dirty snowball that fell to Earth from outer space about a week ago? Wouldn't that be something else to think about? Frank Condon mail to:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" >At 06:51 PM 12/14/97 -0800, you wrote: >>Hello All: >>Did anyone pick up a seismographic signal from the recent large meteorite >>impact in Iceland? If so, then how does it compare to a normal tectonic >>earthquake seismographic waveform? >> > I would think it would look like a surface explosion which I have a pix of >using fftdsp. I don't know where the sensor is located that recorded this >event though. I also recorded a large surface event just this week but did >not correlate the greenland metior with that. I record forward scatter >meteor echos and two channels of remote quake sensors and as I recall they >were not related. The bang as I call it are just one large pulse with very >little long period data and very short, short period data. I think a sonic >boom would look the same. > > >Norman Davis WB6SHI >Email normd@............. >Shingle Springs, Ca, USA it ain't local... > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Martin Brewer" Subject: Re: Recent event Date: Wed, 17 Dec 1997 10:23:31 -0400 Hi Barry, You wrote >Hi all > I picked up some pretty strong surface waves at around 12:00 UTC. I >can't get through to NEIS. Any one pick up them? > Barry > I picked up a strong pulse of 10 sec waves lasting four (4) minutes at 11:26 UTC on 16 December. It was a very short duration for long waves from a distant source. There was nothing from USGS, I think it must be "local" in the Atlantic. Any suggestions? Martin in Bermuda _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: dean sevold Subject: Fwd: Re: Recent meteorite strike Date: Wed, 17 Dec 97 23:28:35 PST Date: Thu, 18 Dec 97 02:37:01 PST From: Groenlandica To: dean sevold Subject: Re: Recent meteorite strike Dear Mr Seavold I can confirm the major strike. For 2-3 sec. the sky were bright as daylight from Disco Bay in North to Nanortalik in the most southern part of Greenland. An helicoprers are looking for the meteorite. One theory says it hit the icecap at the East coast south of Tasiilaq (Ammassalik). I do not know anything about recordings on seismographs. Klaus Georg Hansen Head of Groenlandica National Library POBox 1074 DK-3900 Nuuk Greenland >Dear Sirs: > >I have heard reports of a recent (within a week) meteor impact in Greenland, and would be interested if you could confirm or deny such a report. > >I am a member of a sesmic network, and according to a report I received, the impact was recorded on a seismograph. > >Any information you would have that would clarify this would be appreciated. > >Thank you for your time and trouble. > >Dean Sevold >232 Garner Road >Salt Spring Island >British Columbia >Canada > > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Fwd: Re: Recent meteorite strike Date: Thu, 18 Dec 1997 08:42:33 -0800 The following press statement was posted to sci.space.science ... >Greenland Meteorite Fall Update > > >From baalke@................... (Ron Baalke) >Organization Jet Propulsion Laboratory >Date 16 Dec 1997 23:56 UT >Newsgroups sci.space.science >Message-ID <16DEC199723565518@...................> > > Press statement > > by > > Niels Bohr Institute, Geophysical Dept. > > 971215 20.00UT > >---------------------------------------------------------------------------- > >A big meteor impact has probably occurred in Southern Greenland at 61 25N, >44 26W on Tuesday, December 9th app. 08.11UTC (05.11am local time). The >position is on the ice cap app. 50 kilometers NE of Narsarsuaq Airport. > >The position has been determined on the basis of observations made by a >Danish and a Norwegian trawler near the east coast of Greenland, and a >Danish trawler at a position in the bay off Julianehaab. Based on fairly >accurate direction findings and the fact, that the trawlers were situated on >both sides of Southern Greenland it can be determined, that the meteorite >fell on land. > >The relevant trawlers are: > >Halten Trawl, Norwegian at 62 05N, 41 10W >Regina C, Danish at 60 55N, 51 35W >Timmarut, Danish at 60 13N, 46 43W > >Observations of the satelite lighttrack from Nuuk indicates that the meteorite >passed a bit south of Nuuk in southeasterly direction towards the mentioned >impact site in Southern Greenland. > >Seismic disturbances have been observed on Svalbard and Finmarka (Norway). >These tremors are observed at 08.21UTC and 08.23UTC and are assumed to >relate to the impact or the passage of the meteorite through the atmosphere. >The signals did not allow a seismic localization of the event. The >observations are made by NORSAR (Norwegian Seismic Array), Kjeller, Norway. >Fainter signals were observed in Finland and Germany. The seismic stations >in Greenland (Sonder Stromfjord and Danmarkshavn) has no observations. >Further seismic data will be collected from Iceland and Canada in order to >confirm the visual localization. > >Observations from the satellites ERS1 and ERS2 are being planned. These >satellites observe the surface of the Earth using radar. > >The flashes observed in conjunction with the meteorite were so bright as to >turn night into daylight at a distance of 100 kilometers and can be compared >to the light af a nuclear explosion in the atmosphere. However, we stress >that there is no reason to belive other than natural causes. > >During the day, the position will be overflown by an ice reconnaissance >plane, from the Ice Central in Narsarsuaq on its planned flight from Kap >Farvel to Nuuk. > >The event can in size probably be compared to the Kap York meteorite, that >in prehistoric time fell in Melville Bay, Sassivik south of Thule. Findings >from the meteorite consist of a number of iron meteorites totalling 50 tons. >One of these ironfragments can be seen in Copenhagen outside the Geological >Museum. > >Collecting and studying material from this meteorite has great scientific >value. It is fortunate that the meteorite fell on land, but a search on the >ice cap is difficult and in winter impeded by bad weather and darkness. >Since December 9th 30-100cm of snow has fallen in the area and before summer >smaller fragments will be covered by 3 meters of snow. According to Danish >law, findings of meteorite material must be turned over to the authorities, >in this case they will be the property of the Greenland Home Rule. > >These investigations are coordinated by Geophysical Dept. at the Niels Bohr >Institute, University of Copenhagen in cooperation with: >Tycho Brahe Planetarium, Copenhagen. >Copenhagen Astronomical Society >National Survey and Cadastre, Denmark >NORSAR, Kjeller, Norway >Danish Center for Remote Sensing, Technical University of Denmark > >The information may be qouted, if the source is indicated. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: Recent meteorite strike Date: Thu, 18 Dec 1997 10:36:57 -0600 Interesting There was also a bright fireball seen here in the midwest USA last Friday about 8pm cst. Jim Hannon dsevold@.............. on 12/18/97 01:28:35 AM Please respond to psn-l@............. To: psn-l@............. cc: (bcc: James M Hannon/CedarRapids/Collins/Rockwell) Subject: Fwd: Re: Recent meteorite strike Date: Thu, 18 Dec 97 02:37:01 PST From: Groenlandica To: dean sevold Subject: Re: Recent meteorite strike Dear Mr Seavold I can confirm the major strike. For 2-3 sec. the sky were bright as daylight from Disco Bay in North to Nanortalik in the most southern part of Greenland. An helicoprers are looking for the meteorite. One theory says it hit the icecap at the East coast south of Tasiilaq (Ammassalik). I do not know anything about recordings on seismographs. Klaus Georg Hansen Head of Groenlandica National Library POBox 1074 DK-3900 Nuuk Greenland >Dear Sirs: > >I have heard reports of a recent (within a week) meteor impact in Greenland, and would be interested if you could confirm or deny such a report. > >I am a member of a sesmic network, and according to a report I received, the impact was recorded on a seismograph. > >Any information you would have that would clarify this would be appreciated. > >Thank you for your time and trouble. > >Dean Sevold >232 Garner Road >Salt Spring Island >British Columbia >Canada > > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Fwd: Re: Recent meteorite strike Date: Thu, 18 Dec 1997 17:39:17 -0800 (PST) Thanks Ron for the confirmation of the impact in Greenland! Some eaarlier reports on the network news said that it might have been a small comet. How would they tell the difference? Frank Condon mail to:frankcnd@.......... "Located in the seismic corridor somwhere between Fontana & Mammoth Lakes" >The following press statement was posted to sci.space.science ... > >>Greenland Meteorite Fall Update >> >> >>From baalke@................... (Ron Baalke) >>Organization Jet Propulsion Laboratory >>Date 16 Dec 1997 23:56 UT >>Newsgroups sci.space.science >>Message-ID <16DEC199723565518@...................> >> >> Press statement >> >> by >> >> Niels Bohr Institute, Geophysical Dept. >> >> 971215 20.00UT >> >>---------------------------------------------------------------------------- >> >>A big meteor impact has probably occurred in Southern Greenland at 61 25N, >>44 26W on Tuesday, December 9th app. 08.11UTC (05.11am local time). The >>position is on the ice cap app. 50 kilometers NE of Narsarsuaq Airport. >> >>The position has been determined on the basis of observations made by a >>Danish and a Norwegian trawler near the east coast of Greenland, and a >>Danish trawler at a position in the bay off Julianehaab. Based on fairly >>accurate direction findings and the fact, that the trawlers were situated on >>both sides of Southern Greenland it can be determined, that the meteorite >>fell on land. >> >>The relevant trawlers are: >> >>Halten Trawl, Norwegian at 62 05N, 41 10W >>Regina C, Danish at 60 55N, 51 35W >>Timmarut, Danish at 60 13N, 46 43W >> >>Observations of the satelite lighttrack from Nuuk indicates that the >meteorite >>passed a bit south of Nuuk in southeasterly direction towards the mentioned >>impact site in Southern Greenland. >> >>Seismic disturbances have been observed on Svalbard and Finmarka (Norway). >>These tremors are observed at 08.21UTC and 08.23UTC and are assumed to >>relate to the impact or the passage of the meteorite through the atmosphere. >>The signals did not allow a seismic localization of the event. The >>observations are made by NORSAR (Norwegian Seismic Array), Kjeller, Norway. >>Fainter signals were observed in Finland and Germany. The seismic stations >>in Greenland (Sonder Stromfjord and Danmarkshavn) has no observations. >>Further seismic data will be collected from Iceland and Canada in order to >>confirm the visual localization. >> >>Observations from the satellites ERS1 and ERS2 are being planned. These >>satellites observe the surface of the Earth using radar. >> >>The flashes observed in conjunction with the meteorite were so bright as to >>turn night into daylight at a distance of 100 kilometers and can be compared >>to the light af a nuclear explosion in the atmosphere. However, we stress >>that there is no reason to belive other than natural causes. >> >>During the day, the position will be overflown by an ice reconnaissance >>plane, from the Ice Central in Narsarsuaq on its planned flight from Kap >>Farvel to Nuuk. >> >>The event can in size probably be compared to the Kap York meteorite, that >>in prehistoric time fell in Melville Bay, Sassivik south of Thule. Findings >>from the meteorite consist of a number of iron meteorites totalling 50 tons. >>One of these ironfragments can be seen in Copenhagen outside the Geological >>Museum. >> >>Collecting and studying material from this meteorite has great scientific >>value. It is fortunate that the meteorite fell on land, but a search on the >>ice cap is difficult and in winter impeded by bad weather and darkness. >>Since December 9th 30-100cm of snow has fallen in the area and before summer >>smaller fragments will be covered by 3 meters of snow. According to Danish >>law, findings of meteorite material must be turned over to the authorities, >>in this case they will be the property of the Greenland Home Rule. >> >>These investigations are coordinated by Geophysical Dept. at the Niels Bohr >>Institute, University of Copenhagen in cooperation with: >>Tycho Brahe Planetarium, Copenhagen. >>Copenhagen Astronomical Society >>National Survey and Cadastre, Denmark >>NORSAR, Kjeller, Norway >>Danish Center for Remote Sensing, Technical University of Denmark >> >>The information may be qouted, if the source is indicated. > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Marnie Gannon Subject: Meteorite Date: Thu, 18 Dec 1997 18:42:57 -0700 Here's a great page of the meteorite. It shows a satellite picture of the landing crater in the snow..check it out. http://news.bbc.co.uk/hi/english/sci/tech/newsid_40000/40507.stm Marnie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Marnie Gannon Subject: Re: Meteorite Date: Thu, 18 Dec 1997 19:04:23 -0700 Marnie Gannon wrote: > > Here's a great page of the meteorite. It shows a satellite picture of > the landing crater in the snow..check it out. > > http://news.bbc.co.uk/hi/english/sci/tech/newsid_40000/40507.stm Oops..guess I should say landing area, not landing crater..does look like a crater though, doesn't it? Marnie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Meteorite Date: Thu, 18 Dec 1997 18:24:42 -0700 I liked the little annimation at the end of the message! :> -- ---/---- Charlie Marnie Gannon wrote: > > > > Here's a great page of the meteorite. It shows a satellite picture of > > the landing crater in the snow..check it out. > > > > http://news.bbc.co.uk/hi/english/sci/tech/newsid_40000/40507.stm > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Marnie Gannon Subject: Re: Meteorite Date: Thu, 18 Dec 1997 19:37:27 -0700 Charles Watson wrote: > > I liked the little annimation > at the end of the message! :> > I know :^) ! That BBC science page is pretty cool..well researched with lots of links. I check it often. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Humor - Twelve Commandments of Flaming Date: Thu, 18 Dec 1997 20:22:44 -0700 This was sent out on another list I am on. -Larry ---------------------------------------------- The Twelve Commandments of Flaming Prologue: Flames should be witty, insulting, interesting, funny, caustic, or sarcastic, but never, ever, should they be boring. 1. Make things up about your opponent: It's important to make your lies sound true. Preface your argument with the word "clearly." "Clearly, Fred Flooney is a liar, and a dirtball to boot." 2. Be an armchair psychologist: You're a smart person. You've heard of Freud. You took a psychology course in college. Clearly, you're qualified to psychoanalyze your opponent. "Polly Purebread, by using the word 'zucchini' in her posting, shows she has a bad case of penis envy." 3. Cross-post your flames: Everyone on the net is just waiting for the next literary masterpiece to leave your terminal! From the Apple II RoundTable to X-10 Powerhouse RoundTable, they're all holding their breath until your next flame. Therefore, post everywhere. 4. Conspiracies abound: If everyone's against you, the reason can't possibly be that you're a sh--head. There's obviously a conspiracy against you, and you will be doing the entire net a favor by exposing it. 5. Lawsuit threats: This is the reverse of Rule #4 (sort of like the Yin & Yang of Flaming). Threatening a lawsuit is always considered to be in good form. "By saying that I've posted to the wrong group, Bertha has libeled me, slandered me, and sodomized me. See you in court, Bertha." 6. Force them to document their claims: Even if Harry Hoinkus states outright that he likes tomato sauce on his pasta, you should demand documentation. If Newsweek hasn't written an article on Harry's pasta preferences, then Harry's obviously lying. 7. Use foreign phrases: French is good, but Latin is the lingua franca of flaming. You should use the words "ad hominem" at least three times per article. Other favorite Latin phrases are "ad nauseum," "veni, vidi, vici," and "fetuccini alfredo." 8. Tell 'em how smart you are: Why use intelligent arguments to convince them you're smart when all you have to do is tell them? State that you're a member of Mensa, or Mega, or Dorks of America. Tell them the scores you received on every exam since high school. "I got an 800 on my SATs, LSATs, GREs, MCATs, and I can also spell the word 'premeiotic'." 9. Accuse your opponent of censorship. It is your right as an American citizen to post whatever the hell you want to the net (as guaranteed by the 37th Amendment, I think). Anyone who tries to limit your cross-posting or move a flame war to e-mail is either a communist, a fascist, or both. 10. Doubt their existence: You've never actually seen your opponent, have you? And since you're the center of the universe, you should have seen them by now, shouldn't you? Therefore, THEY DON'T EXIST! This is the beauty of flamers' logic. 11. Lie, cheat, steal, leave the toilet seat up. 12. When in doubt, insult: If you forget the other 11 rules, remember this one. At some point during your wonderful career as a Flamer you will undoubtedly end up in a flame war with someone who is better than you. This person will expose your lies, tear apart your arguments, make you look generally like a bozo. At this point, there's only one thing to do: INSULT THE DIRTBAG!!! "Oh yeah? Well, your mother does strange things with vegetables." EXAMPLE...for the Rookie Flamer: > Dear Joe, I object to your use of the word "dear." It shows you are a condescending, sexist pig. Also, the submissive tone you use shows that you like to be tied down and flagellated with licorice whips. > While I found your article "The Effect of Belly-Button Lint > on Western Thought" to be extremely thought-provoking, "Thought-provoking?" I had no idea you could think, you rotting piece of swamp slime. > it really shouldn't have been posted in rec.scuba. What? Are you questioning my judgement? I'll have you know that I'm a member of the super-high-IQ society Menstruate. I got an 800 on my PMS exam. Your attempts constitute nothing less than censorship. There is a conspiracy against me. You, Riff Raff, and Simon Sinister have been constantly harassing me by e-mail. This was an ad hominem attack! I have therefore cross-posted this to alt.flame, rec.nude, comp.graphics, and rec.arts.wobegon. > Perhaps you should have posted it in misc.misc. It is my right, as granted in the Bill of Rights, the Magna Carta, the Bible, and the Koran to post whereever I want to. Or don't you believe in those documents, you damn fascist? Perhaps if you didn't spend so much time sacrificing virgins and infants to Satan, you would have realized this. > Your article would be much more appropriate there. Can you document this? I will only accept documents notarized by my attorney, and signed by you in blood. Besides, you don't really exist anyway, you AI project, you. *************End*************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: High Res Broadband Vertical Seismometer info at the PSN meeting Date: Thu, 18 Dec 1997 20:51:26 -0700 Hi Everyone, I just talked to Sam Gazdik and he was able to get the poster, used at the AGU meeting, that describes S-T Morrissey Broadband vertical sensor. He has also received some additional information on the sensor plus info on a horizontal version. The poster and all of the info that Sam has will be at the meeting on Saturday. I will contact S-T to see if I can post the info on my web site for all to see. Regards, Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Humor - Twelve Commandments of Flaming Date: Fri, 19 Dec 1997 18:28:19 +1200 absolutely brilliant still laughting thanks Larry Merry Xmas from New Zealand Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re:additional Date: Fri, 19 Dec 1997 18:32:55 +1200 I forgot to add a HUGE thanks for all the help throughout the year with what we have done together and what you have done for the PSN as a result my seismology hobby is no longer the same, I could never have imagined the fantastic change. tnx Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: It's nearly here! Date: Fri, 19 Dec 1997 08:15:02 +0000 ********************************************************* ********************************************************* ******>>>>>MERRY<<<<<******************************** ********************************************************* ********************************************************* *******************************>>>>>XMAS<<<<<********* ********************************************************* ********************************************************* ********************************************************* ********************************************************* **********and a Happy New Year*************************** ********************************************************* ********************************************************* To All on PSN.................................... ................................................From England (Albert) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roger Baker Subject: Micro-Lehman? Date: Fri, 19 Dec 1997 04:35:02 -0600 Friends, Here's an easy and interesting little experiment that could lead to a small seismographic instrument related to a Lehman. Was it Beniot (sic) who came up with a vertical torsion seismometer that the following configuration might also resemble? I have learned how to tension and mount tiny nylon monofilaments with a few grams, which filaments have a breaking strength on the order of half an ounce, and look similar to about a 15 cm string on a glass support bow. (Fine nylon fibers unraveled from twine are strong uniform and more convenient for experimentation than metal or glass fibers). I then cut out a V-shaped piece out of thin aluminum flashing, about 5x7 cm and weighing a few tenths of a gram and taped the legs of the V flat to the middle of the filament so the pointed end of the little beam is free to pivot around the filament. The free end of the little beam then swings around like the beam of a Lehman and the exact tilt of the fiber mount from the vertical determines the rest point and the natural period of the oscillations, etc. As you may imagine, the top portion of the filament is stretched outwards where the top the beam is taped to the filament, while the lower portion is forced inwards in the opposite direction, since the center of gravity of the little aluminum beam is supported off to one side of the filament a few centimeters; the beam is mounted like a flag sticking out sideways from the middle of the fine torsion fiber. The advantage is that there is no stickiness or hysteresis at all in the suspension, since the mounting is the mid-section of a torsion fiber. The horizontal rest position is extremely sensitive to tilt like a Lehman, and naturally the light flat little beam is also extremely sensitive to air currents. Accordingly, I put the device in a styrofoam cooler and then covered it with a towel. I used my favorite LED and phototransistor combination with a narrow gap as a displacement detector, and a little aluminum flag mounted on the tip of the beam to interrupt the beam. With suitable electronic amplification, the beam is always in motion, picking up and registering some sort of signals centered on its natural oscillation period of about two seconds. These must either be seismic vibrations, or else pneumatic disturbances of some sort I would imagine. Nothing magnetic about this beam. Assuming that the signals/noise I see are actually pneumatic and related to small convection currents rather than seismic disturbance in origin, then as the device is scaled up, this situation ought to change to favor seismic sensitivity. The device should show the normal properties of a Lehman, but based on a vertical torsion suspension instead of pointed pivots. This also raises the interesting issue of the optimum size or beam mass a somewhat larger version. I suspect that a very sensitive instrument could have a beam weighing an ounce or less. A practical instrument of this sort would certainly benefit from using force feedback since the rest position of the beam is subject to more uncertainty as the period is lengthened. My miniature beam can have its period lengthened to ten seconds of so with a critical adjustment (by sliding wedges under the cooler) but then it tends to wander around and getting it properly centered at rest to take full advantage of the great sensitivity of the optical sensor gets pretty hard to do. This is all the result of a few hours rather than days of experimentation, but the experiment was instructive and rather easy to set up. Happy Holidays, Roger Baker _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: TMichel917 Subject: Re: Streckeisen seismometers Date: Fri, 19 Dec 1997 08:49:10 EST Hi Meredith! You can find detailed information about the Streckeisen seismometers in the following articles: Wielandt, E. (1976) Ein astasiertes Vertikalpendel mit tragender Blattfeder. (Astatic Vertical Pendulum Supported by a Leaf Spring) J. Geohys. 41, 545-547 Describes a spring geometry which is used in the STS-1V (vertical) in a slightly altered version. Wielandt, E., and Streckeisen, G. (1982) The leaf spring seismometer: Design and performance. Bull. Seismol. Soc. Am. 72, 2349-2367. Describes the mechanics and electronics of the 20 sec STS-1 in detail. Wielandt, E., and Steim, J. M. (1986) A digital very-broad-band seismograph. Annales Geophysicae 4, 227-232 Describes the electronics of the very-broad-band (360 sec) version of the STS-1. Regards Torsten Michel _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: Micro-Lehman? Date: Fri, 19 Dec 1997 08:26:55 -0800 Roger -- As another source of hardware for experimentation, you might consider a taught-band meter movement. Instead of jewels, these use a taught fiber of (usually) berrylium copper for a suspension. If you hang your mass on the meter's needle, you could sense position, and the meter's coil could be used for force feedback. Happy holidays to all -- Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Micro-Lehman? Date: Fri, 19 Dec 1997 09:31:35 -0700 Karl Cunningham wrote: > > As another source of hardware for experimentation, you might consider a > taught-band meter movement. Instead of jewels, these use a taught fiber of > (usually) berrylium copper for a suspension. If you hang your mass on the > meter's needle, you could sense position, and the meter's coil could be > used for force feedback. Where would you obtain berrylium copper wire (fiber)? What would be an appropriate gauge? -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ken Navarre Subject: Re: N.Cal meeting Dec 20th. Date: Fri, 19 Dec 1997 10:47:41 -0800 (PST) On Tue, 25 Nov 1997, Larry Cochrane wrote: [snip] > Since > more people can come on Dec 20th then the 13th, we will have it on the > 20th. The time will be 11:00am and the location is building 8, Room 8111, > at the Menlo Park USGS campus. Are we still on for an 11:00 am meeting @ bldg. 8??? Looking forward to seeing some "old" faces as well as a bunch of the newer members. Hope folks will bring goodies for "show & tell"! Ken _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roger Baker Subject: Re: Micro-Lehman? Date: Fri, 19 Dec 1997 13:01:18 -0600 >As another source of hardware for experimentation, you might consider a >taught-band meter movement. Instead of jewels, these use a taught fiber of >(usually) berrylium copper for a suspension. If you hang your mass on the >meter's needle, you could sense position, and the meter's coil could be >used for force feedback. > >Happy holidays to all -- > >Karl Cunningham >La Mesa, CA. >PSN station #40 >karlc@....... Friends, As Karl points out, a torsion suspension meter movement would be a good place to start. You would presumably unbalance the meter by gluing up to a gram or so of weight to the end of the meter pointer along with a flag and optical detector. Then by carefully tilting the meter, you could get a long period. But I would hate to kill a working meter of the best kind. In the homebrew example I cited earlier, a suitable force feedback arrangement in my opinion would be to mount a little iron wire mounted perpendicular on the end of the beam and then have a pair of 12v reed relay coils mounted to either side of the beam compete in trying to draw it inside themselves on their side. Remember the beam is nearly perfectly stationary with a properly operating force feedback setup so centering and beam travel inconveniences are eliminated. But as a practical matter, having the beam free to swing maybe 5 degrees is useful if you want to adjust the natural period. Also a torsion suspension can have various modes of vibration such that the beam rocks and wobbles in every way possible -- and these vibrations can take seconds to damp down with my arrangement, when its subjected to jolts. Presumably force feedback would help calm down these parasitic vibration modes, assuming they exist enough under normal operation to cause a problem. -- Yours, Roger _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Conductivity Date: Fri, 19 Dec 1997 12:03:24 -0700 (MST) Hey Everyone, I have a quick question about conductivity in solids. Is a higher linear density of metal atoms in a particular direction more or less conductive??? ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: Conductivity Date: Fri, 19 Dec 1997 13:46:47 -0600 John, Interesting question. I am not sure it can be answered without a little more explanation of the problem. For grins I did a web search on "anisotropic conductivity" and got 51 hits most on very heavy subjects. A good book on "solid state physics" would be a place to start. JIm Hannon hernlund@....... on 12/19/97 01:03:24 PM Please respond to psn-l@............. To: psn-l@............. cc: (bcc: James M Hannon/CedarRapids/Collins/Rockwell) Subject: Conductivity Hey Everyone, I have a quick question about conductivity in solids. Is a higher linear density of metal atoms in a particular direction more or less conductive??? *************************************************************************** *** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ *************************************************************************** *** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Mammoth Mag pool Date: Fri, 19 Dec 1997 15:36:55 -0700 You'll get a chuckle out of this... So I call the Mammoth Times newspaper in Mammoth Lakes, California, to see if anyone felt today's M3.8 earthquake and the person says, "Oh, yea! We had an $0.25 office pool to see who could guess the magnitude". It was said the winner walked away with $2.00! -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: ACole65464 Subject: Re: Micro-Lehman? Date: Fri, 19 Dec 1997 22:52:11 EST Karl and the PSN Group, Some months back I did an experiment with an old volt meter movement to see if I could make a vertical seismometer with it too. It only had jewel pivots but showed some sensitivity to seismic background noise when turned up on its side. It had a small piece of aluminum foil bonded to the end of the 3" needle. A light beam was chopped by the alum foil, proportional to the ground motion and the meter's coil was used for feedback. When I get more time I will make the taut beam mechanism as it has been pointed out to be a better idea. Thanks for opening up this discussion. Merry Christmas to all. Allan Coleman _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: N.Cal meeting Dec 20th. Date: Fri, 19 Dec 1997 20:04:54 -0700 We sure are... See you tomorrow.... -Larry At 10:47 AM 12/19/97 -0800, you wrote: >Are we still on for an 11:00 am meeting @ bldg. 8??? >Looking forward to seeing some "old" faces as well as a bunch of the >newer members. Hope folks will bring goodies for "show & tell"! > >Ken _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Al Allworth" Subject: Re: Micro-Lehman? Date: Fri, 19 Dec 1997 20:52:58 -0800 -----Original Message----- From: ACole65464 To: psn-l@............. Date: Friday, December 19, 1997 7:54 PM Subject: Re: Micro-Lehman? >Karl and the PSN Group, > > Some months back I did an experiment with an old volt meter movement to see >if I could make a vertical seismometer with it too. It only had jewel pivots >but showed some sensitivity to seismic background noise when turned up on its >side. It had a small piece of aluminum foil bonded to the end of the 3" >needle. A light beam was chopped by the alum foil, proportional to the ground >motion and the meter's coil was used for feedback. > When I get more time I will make the taut beam mechanism as it to Many meters are built with taut band movements. All you have to do is find one. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Charlie Rond Subject: Re: N.Cal meeting Dec 20th. Date: Sat, 20 Dec 1997 02:24:26 -0600 >Are we still on for an 11:00 am meeting @ bldg. 8??? >Looking forward to seeing some "old" faces as well as a bunch of the >newer members. Hope folks will bring goodies for "show & tell"! Sure wish I could join you guys. Have a great meeting! How about posting "minutes" or a summary of what happens? Charlie Rond -\/\--Public Seismic Network-Memphis rond@................ (901) 360-0302 [ free BBS ] http://gandlf.ceri.memphis.edu/~rond http://gandlf.ceri.memphis.edu/~rond/psn _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Arie Verveer Subject: Article on Meteorite Seismic Impacts Date: Sun, 21 Dec 1997 00:15:40 +0800 Hi, You may be interested in these two articles on "meteorite impacts" They can be located at http://www.iinet.com.au/~ajbv/ The reference is at the bottom of the page and the data is in ".pdf" format. Regards Arie Verveer _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: Micro-Lehman? Date: Sat, 20 Dec 1997 09:06:10 -0800 Charles -- The taught-band meter I was referring to has the berrylium copper suspension built in already, and as I remember use a flat ribbon perhaps 0.5mm wide. These analog meter movements are particularly good against vibration and shock since the taught band just rebounds rather than suffering damage as jeweled movements do. But, as to your question, You might try California Fine Wire, Inc. (see http://www.calfinewire.com/index.htm ) This resource was suggested to me by Bob Thomasson in a post to this list 11/14/97. -- Karl At 09:31 AM 12/19/97 -0700, you wrote: >Where would you obtain berrylium copper wire (fiber)? >What would be an appropriate gauge? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: Micro-Lehman? Date: Sat, 20 Dec 1997 09:06:23 -0800 I have purchased several over the years at electronic-oriented swap meets for the $1-$2 range. If you look through the glass at the suspension system, you can see what you have. The ones I have seen don't have the usual hair spring, but rely on the band for zeroing. Phaostron is one maker of them, and they sometimes say what it is in the corner of the scale. After modification, it may be possible to put the meter back in its case using some sealer to make an air-tight enclosure. -- Karl At 08:52 PM 12/19/97 -0800, you wrote: >Many meters are built with taut band movements. All you have to do is find >one. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: Micro-Lehman? Date: Sat, 20 Dec 1997 11:54:03 -0600 (CST) If you replace the aluminum foil withthe sensing vane of a VRDT it will also work, especially with a large taught-band EDGEWISE meter turned on edge and the centering adjustment cranked to one end to support the slight mass of the vane. However, I had difficulty modeling it as a triple feedback vertical because the mechanical period is quite short, th emass is minimal, and the meter coil resistance is quite large compared to its' generator constant. It still might make a handy short-period sensor. But real very broadbands are more fun. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Seisguy Subject: Re: N.Cal meeting Dec 20th. Date: Sat, 20 Dec 1997 13:02:21 EST In a message dated 97-12-20 03:29:50 EST, you write: > Sure wish I could join you guys. Have a great meeting! > > How about posting "minutes" or a summary of what happens? > That's a great idea Charlie. I can't make it either but would love to see a summary also. Mike O'Bleness Northridge, Ca _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: Micro-Lehman? Date: Sat, 20 Dec 1997 10:35:32 -0800 Sean-Thomas -- I'm curious about your VRDT. Does the VR stand for variable reluctance? Do you excite it with DC or AC? What kind of resolution, dynamic range, SNR can you get? I'm not familiar with triple feedback. Is this the same as proportional-integral-differential (PID)? -- Karl At 11:54 AM 12/20/97 -0600, you wrote: >If you replace the aluminum foil withthe sensing vane of a VRDT it will >also work, especially with a large taught-band EDGEWISE meter turned on edge >and the centering adjustment cranked to one end to support the slight >mass of the vane. However, I had difficulty modeling it as a triple feedback >vertical because the mechanical period is quite short, th emass is minimal, >and the meter coil resistance is quite large compared to its' generator >constant. It still might make a handy short-period sensor. >But real very broadbands are more fun. >Regards, >Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: Micro-Lehman? Date: Sat, 20 Dec 1997 00:18:59 -0800 Sean-Thomas Like Karl, I am curious also. Tell us more about very broadband seismometers. Barry S-T Morrissey wrote: > > If you replace the aluminum foil withthe sensing vane of a VRDT it will > also work, especially with a large taught-band EDGEWISE meter turned on edge > and the centering adjustment cranked to one end to support the slight > mass of the vane. However, I had difficulty modeling it as a triple feedback > vertical because the mechanical period is quite short, th emass is minimal, > and the meter coil resistance is quite large compared to its' generator > constant. It still might make a handy short-period sensor. > But real very broadbands are more fun. > Regards, > Sean-Thomas > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: VBB feedback Date: Sat, 20 Dec 1997 14:38:47 -0600 (CST) Karl, Barry, et.al, I presented a paper at the fall AGU meeting on a homemade broadband I designed last spring; here is the abstract: ______________________ Abstract submitted for 1997 fall AGU meeting: A Homemade High Resolution Broadband Vertical Seismometer Constructed from Consumer Hardware and Electronics Items for School and Personal Use. Sean-Thomas Morrissey (Dept. of Earth and Atmospheric Sciences, St.Louis University, 3507 Laclede; St. Louis MO, 63103; 314 977 3129; sean@........... The need for an affordable modern broadband seismometer and seismograph system has been fulfilled by the construction of a very sensitive vertical seismometer using only consumer hardware and electronics components, with a digital multimeter and a PC as the digital seismograph. Key elements of the design are a leaf-spring suspension (the blade of a drywall taping knife), a displacement transducer with nanometer resolution (made from two miniature audio transformers), and a very common but powerful feedback transducer (the voice coil and magnet of a large stereo speaker). The 60 cm long frame is of storm door aluminum; the hinges are bronze weatherstrip, epoxied in place. The digitizer is a consumer digital multimeter with serial output to the PC; digital seismograms are made with Mathcad. Another digitizer uses a VCO and a PC soundcard. The broadband sensor normally operates at a "natural period" of 150 seconds using a classical triple feedback system, which readily allows configurations of To from 30 to 300 seconds. The velocity output is 1600 V/m/s, which the transfer function indicates is flat from 100 seconds to 30 hz. Auxiliary windings added to the main (speaker) coil allow for dynamic temperature and pressure compensation of the mass position, as well as step calibration. Without a pressure containment, the sensor readily shows atmospheric "acoustic gravity" waves at periods greater than 10 minutes; the "mass position" output shows earth tides. Broadband seismograms of M > 5.5 events almost anywhere are the normal record. They compare favorably with local broadband records from commercial sensors. _________ end of abstract ---------- After the meeting, Sam Gazdik asked me if I could send him the poster paper materials for the PSN meeting today at the USGS, which I did. So I presume that those attending the meeting are seeing the poster. I have received numerous queries about the sensor, to which I have sent the following form-email response: ____________________ form-email::::: Thanks for the interest in the homemade seismometer. Unfortunately I am not able to supply any detailed drawings and schematics of it at this time. Since it is entirely a home-hobby project, I cannot spend funded University time here to work on it, although I am working on trying to get some support to do so. I am hoping that I might have a useful information package assembled by March, possibly on my web page, which is currently nearly blank. But I did write a draft paper on the project back in September, and I am currently upgrading it to reflect the current status as shown in the poster. However it is a long way from complete documentation, even if you have the photographs of the prototype. However, when I have suitably revised it, I can send you the revised draft and some photos, and you can take it from there. I am currently assembling a second instrument that should solve some of the moment-of-inspiration design problems of the prototype. For the electronics, I am considering having it all pre-assembled by some local firm (maybe Sprengnether Instruments), and provided in some sort of kit form. Of course, if you have the resources, it is easy to fabricate. And of course, the most satisfying part of making the instrument is taking an Xacto knife and metal shears to a brand new stereo speaker to make the feedback transducer. ______________ end of form-email So to specifically answer your question, VRDT is Variable Reluctance Displacement Transducer. It consists of two open-faced inductors with ferrous cores separated by 1 to 2 mm, with a ferrous vane in between to sense motion; it is commonly used in pressure transducers (Validyne) where the inductors are imbedded in the housinng, and the diaphram is the moving element. I have used the Validyne electronics module for various applications (was $100). In operation, it is very similar to the LVDT; in fact the same oscillator/ demodulator can be used; a MAJOR advantage of the VRDT is that it is only sensitive to movement of the sensing vane along the axis between the inductors; it is NOT sensitive to lateral movement parallel to the core faces. THis makes it ideal for seismometers, whose booms and suspensions allow considerable lateral motion, which makes using a LVDT very difficult because of the minimal (0.1mm) clearance between the core and the coils. For some applications, I use a Validyne electronics with a Schaevitz LVDT to make microbarometers with micro-bar resolution; however, I use the LVDT in variable reluctance mode (not driving the center coil) for lower noise and better linearity. For the homemade seis, I make the VRDT with 500 ohm audio transformers, whose cores are reassembled into an open E pattern. Details are in my curently-being-updated paper. Typical sensitivity is 50 to 100 mv/micron. Regarding the triple feedback: it is also described in the paper; I also started a separate paper on just the feedback concepts, but it is unfinished. In essence, it uses the diplacement output voltage to provide a differential feedback (through a capacitor), a proportional feedback (through a resistor), and an integral feedback (through an integrator of 10 to 200 seconds, and a series resistor). I use a mathematical model of the transfer function to determine these component values for a given response, which is flat to velocity from tens of hz to anywhere from 10 to 300 seconds. It is also in the paper, and can be run with Mathcad. I have confirmed the response by comparing the FFT of a step displacement calibration pulse with the transfer function; it agrees perfectly. An important point is that the optput of the displacement transducer is just that without the feedback; when (and only when) the feedback is connected, the same output is the flat velocity response. I also was considering making some gestimates about the parameters of your own force-balance design, and modeling it as a triple feedback sensor. I am sorry I don't have this info available on my web page; it is all here at home, for now. If you are really anxious for a copy of the paper, send a self addressed 9x11 envelope with enough postage for about 30 pages to my web page address (www.eas.slu.edu/People/Staff/STMorrissey). (Same as on abstract above). And I have one special request: if you respond to this email, PLEASE TURN OFF the option that sends a copy of my mail back to me. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Date: Sat, 20 Dec 1997 15:00:12 -0600 (CST) LIST [ALPHA] _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: dean sevold Subject: Fwd: Local information on recent meteorite strike Date: Sat, 20 Dec 97 15:41:50 PST Date: Sat, 20 Dec 97 12:31:15 PST From: Klaus Georg Hansen To: dean sevold Subject: Local information on recent meteorite strike Dear Dean Sevold Thanks for you mail. It is now Saturday 20 December evening (local Greenlandic time): We have just heard the following in the news from KNR (Greenland's radio): Yesterday (Friday) one of the Danish Airforce's Golfstream overflew a new part of the ice cap in the search for the meteorite. From a latitude of 10 km a formation with a diameter of app. 1 km was interpreted as a possible meteorite impact area. The area is located 170 km east of Nuuk ('Godthaab' on older maps). To day (Saturday) a new research in the area was planed, but bad weather prevented any overflying of the area. Torben Risbo from Niels Bohr Institute in Denmark told KNR a SAR-flying is planed in Greenland from January 2nd 1998 and the following days. Now two possible impact areas are located; one near Narsarsuaq in the most southern part of Greenland and one 170 km east of Nuuk. At one location on the West coast people had felt someearth tremor at the time of the strike. That is in the settlement of Fiskenaesset south of Nuuk. Personally I can add my assistent was awake that morning and she saw the 'fireball' in the sky. Acording to her the strike area is east of Nuuk - so I believe the meteorite is to be found east of Nuuk. Marry Christmas and happy New Year Klaus Georg Hansen ************************************* Klaus Georg Hansen P.O.Box 1074, DK-3900 Nuuk, Greenland ************************************* _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ken Navarre Subject: Menlo Park Meeting Date: Sat, 20 Dec 1997 20:11:28 -0800 (PST) Hi folks, the meeting today was great. We got started on schedule and had a nice turnout. In attendance were: Edward Cranswick, Golden Co. Larry Cochrane, Redwood City, Ca. Steve Hammond, San Jose, Ca. Ted Blank, San Jose, Ca. Jan Froom, Gilroy, Ca. Sam Gasdik, Oakland, Ca. Mark Halliday, Ben Lomond, Ca. John Griffin, Mill Valley,Ca. Jerry Hammes, Palo Alto, CA Bob Ogburn, Daly City, CA Roger Griggs, Oakly, CA and myself from Sunnyvale, Ca. Sam brought a really splendid dispaly that he got from Sean-Thomas Morrissey that detailed his broadband vertical sensor. If you haven't seen the information it is a sensor that uses a piece of spring metal that is obtained from a drywall scrapper. Looks like a great project. They will try to get the information scanned and posted on the PSN web page. Give it a look when it appears. Pretty slick! Edward had a beautiful huge poster that he used at the AGU meeting that showed the California contingent of the PSN and our distribution, purpose, and potiential. Made my hair (what little I still have) stand on end. One of our former USGS sponsors, Leif Wennerberg, has gotten "out of the business" and left a treasure trove of books and pamplets that we picked over. Jerry is going to keep the leftovers so we can build a "library" of related books for those interested. We all spent the better part of an hour going over our individual "bios". Sharing what led us to join this ecclectic (and esteemed) group of individuals. Ted reported that he and Larry will be working to complete the support of Ted's EMON ver 7 so that it supports Larry's cards. He said that the new version is almost completed except for identifying some of the addresses. We should look forward to the new EMON soon. Then we had lunch... huge pizzas were brought in courtsey of Edward. Thanks Ed!!! We really porked out and chatted about our individual interests. Ted had EMON running on one laptop. I had another acquisition program running that supports the LPT parallel port A/D pulg. At least it used to until I managed to drop the A/D adapter onto the hard floor :( Heck, I needed a new project anyway...) Larry had SDR running but we never let him finish hooking up the system because we were having too much fun babbling with one another. We had a great time. Then Edward made a presentation whose topic was PSN - A model for a new relationship between the Survery and Society. He had a lot of overheads and wowed us with all kinds of graphics. then he showed us the coolest one of all... The Calnet system is comprized of hundreds of sensors throughout northern and central California. This overhead slide showed what happens when you arrange the data from all the sensors in the network aligned by latitude. From 38 degrees to 49 degrees N. They lined up all the P waves and filtered the output. the result was a display that showed a progression of straight lines that formed when the different waves arrived. You'd hardly notice the pattern just by looking at the data from one, two, or even a dozen sites. But when you stick the data from the entire system together you get a startling arrangement that clearly shows the different waves as they arrived. The P, pP, PP, PcP, pPcP, and the ScP were all apparent. We all went ga ga over this one. Larry will be posting it to the web site for all of you to enjoy. Ted suggested that we get a sweatshirt with it on it, it was soooooooo cool!!! (Some people might suggest that we get a life but I'd have to admit that all of us really dug this one!!!) Edward suggested that perhaps the members of PSN - at least the ones at this meeting were all "closet teleseismologists... we like the big ones far far away...) Before we rapped up the meeting we discussed the format of the PSN files. Ted remarked that as the software/hardware has evolved we need to let the software define the type of file that Quakeview or SDR is reading. Some of the newer format files apparently can't be read by Quakeview. No decision was made but it was noted that it would be nice if the software would let the operator know if the file was not readable what version of what program would read it. We also kicked around the idea of developing a standardized PSN sensor that could be calibrated. Doing so would allow us to provide information as to what local ground motion was doing from a single event. If all our machines were calibrated then investigators could draw some conclusions in areas of maximum shaking. Of course we would need good timekeeping so we talked a bit about that. Edward showed the distribution of Calnet sites in California. It was immediately apparent that most of the sites are located on bedrock in the hills and mountains. There was a discernable gap in coverage in the valleys where most of us live here in California. It is specifically *that* area that is of interest to most of the people in the state because that is where most of the damage and injuries will occur in major events. That is the area where there is a lot of interest in how the different ground structure result in different types of shaking and higher amplitudes. this is the same area where the PSN can be of real service to investigators. That led to the comment that all of us need to be sure that our systems stay on-line during an event. We should all do our best to have a UPS on the systems, have them bolted down so they will remain up and recording, and to develop some strong motion sensors so we don't saturate or clip. Maybe some of us can spend some time looking at some strong motion projects that we can share with one another. Well, we had a lot of fun, shared some stories, laughs, and ideas. We'll have to have another one, perhaps in the spring or summer. In the meantime, lets get our equipment nailed down, the UPS systems on line, and collect some good data. Larry is cranking out boards for us. So far he has munti channel filter/amp cards, demod cards, SG cards, and A/D cards with time correction features. He and Ted are working on some software mods that will make the data collection easier. We need to get more stations up and running and to make contacts in the schools and the community to increase public awareness of our projects as well as the USGS projects. (maybe we can wait til after Xmas to do this...) Everyone should have made out there Xmas list by now. Santa could probably use a bit of help guiding our spouse's choices of exactly which A-D card we want in our stocking - all hung with care... For me, I'm hoping Santa brings my spiffy new S-G card or maybe 90 lbs of concrete for my new sensor pad... Take care everybody. Thanks to everyone who showed up. Special thanks to Edward and Larry for putting the whole thing to gether! Ken PS Sorry for the typos. My keyboard died and some of the keys need to be REALLY pounded to get to work. Gotta get to Fry's to get another... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Charlie Rond Subject: Re: Menlo Park Meeting Date: Sun, 21 Dec 1997 03:52:31 -0600 Ken, Thank you so much for chronicling the meeting for the rest of us who wanted to be there but couldn't! Though we are out here in the boonies, you made us feel a part of the get together. And what a slate of names in attendance!! It sounds like the roster at an all-stars game. Keep up the good work - all of you! And HAPPY HOLIDAYS! Charlie Rond -\/\--Public Seismic Network-Memphis rond@................ (901) 360-0302 [ free BBS ] http://gandlf.ceri.memphis.edu/~rond http://gandlf.ceri.memphis.edu/~rond/psn _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Re: Menlo Park Meeting Date: Sun, 21 Dec 1997 08:03:28 Sounds like a realy great time. Will have to try and make the next one. I was wondering if anyone is working on a a/d interface that would work on a cheap lap top. It would be good for both low power consumption and and portability. The cheapest a/d right now is the R/S or dataq modual but only two channel By the way I have got a VCO now working with my lehman so it feeds a tone into fftdsp. I have two channels of remote sensor with mine in the middle and then on the right I have forward scatter metior detection. 4 channels. Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: Menlo Park Meeting Date: Sun, 21 Dec 1997 10:42:25 -0600 (CST) Ken, Thanks for the review of the meeting, expecially in such a timely fashion. I also want to thank Sam Gazdick for putting up my AGU poster on the homemade broadband leaf spring vertical. It started out as just a challenge to replicate the performance of the expensive commercial broadbands once I knew that the transfer function model would accurately predict the response of whatever I made at home. But I have received considerable encouragement to continue the project for the benefit of the PSN and schools, museums, etc. As you might guess, the documentation part of the project is boring but needs to be done. As for your speculation about being "closet teleseismologists", I would suggest that being a "broadband" seismologist is even more fun: to have a single instrument record the 3.0 quake in the next county on the same record as the 6.5 event in Tibet definitely keeps up the interest in seismology. And with the inherent linearity and dynamic range of a triple fedback sensor (gt. 120db), the low-gain output is also a strong-motion output (at around 100 V/M/sec, compared with the normal output of 3200 V/M/s). Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: Menlo Park Meeting Date: Sun, 21 Dec 1997 09:24:52 -0800 Ken -- Thanks very much for the meeting report. I enjoyed reading it very much. It increased my resolve to be sure to make the next one. Were any group pictures taken that could be scanned and put up for the rest of us to see? Thanks again, Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: Menlo Park Meeting Date: Sun, 21 Dec 1997 01:20:39 -0800 Ken I had great plans to attend. A company Xmas party on Friday night together with last minute Xmas shopping took priority. I'm sorry I missed seeing you guys again. Barry S-T Morrissey wrote: > > As for your speculation about being "closet teleseismologists", I > would suggest that being a "broadband" seismologist is even more fun: > to have a single instrument record the 3.0 quake in the next county on the > same record as the 6.5 event in Tibet definitely keeps up the interest > in seismology. And with the inherent linearity and dynamic range of > a triple fedback sensor (gt. 120db), the low-gain output is also a > strong-motion output (at around 100 V/M/sec, compared with the normal > output of 3200 V/M/s). > A compact,low powered,wide gain sensor is what I'm shooting for. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Darrell Collins Subject: a/d interface Date: Sun, 21 Dec 1997 14:29:22 -0700 At 08:03 AM 12/21/97, you wrote: >I was wondering if anyone is working on a a/d interface that would work >on a cheap lap top. It would be good for both low power consumption and >portability. I think what you are looking for was in the Oct 23 issue of EDN magazine. It is an 8 chan, 12 bit A/D that plugs into the Par port on a PC (laptop). Uses the ultra-low power MAX147 chip and a MAX872 to power it. The 12 bit would most likely be suited to a portable since set-up, adjustment, temp control and everything else that affects a seismometer would be just noise in a 16 bit system. And the software is written and in the EDN web site. The library should have a copy, if not let me know and I'll fax you a copy. If Santa comes through, I'll scan it and e-mail you a copy! Darrell WA7DSV _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: a/d interface Date: Sun, 21 Dec 1997 03:09:17 -0800 Hi In the Dec Circuit Cellar magazine there was an outfit that had a 8 chan 12 bit plug in for the parallel port. ADNAV Electronics. www.tgn.net/~adnav . I haven't checked out the web site but they the adaptor is $99. Barry Darrell Collins wrote: > > At 08:03 AM 12/21/97, you wrote: > >I was wondering if anyone is working on a a/d interface that would work > >on a cheap lap top. It would be good for both low power consumption and > >portability. > > I think what you are looking for was in the Oct 23 issue of EDN magazine. > It is an 8 chan, 12 bit A/D that plugs into the Par port on a PC (laptop). > Uses the ultra-low power MAX147 chip and a MAX872 to power it. The 12 bit > would most likely be suited to a portable since set-up, adjustment, temp > control and everything else that affects a seismometer would be just noise > in a 16 bit system. And the software is written and in the EDN web site. > > The library should have a copy, if not let me know and I'll fax you a copy. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: Re: Menlo Park Meeting Date: Sun, 21 Dec 1997 20:25:49 EST TO: SEAN-THOMAS I am totally new in this hobby. However, I am intrigued with your project. Could you please describe in terms a totally new person to the hobby could understand how a leaf spring verticle seismometer is constructed (not the electronics just the mechanicals). Does it have a boom (pendilum), and if so how long? Is it made simular to a Lehman design but with some sort of spring? Does it look like the one made by the "Amateur Seismologist" company in Montrose, Ca. which is a verticle seiosmometer with a spring attached to the boom? Any assistance you could provide would be appreciated. Thanks Jim Allen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ken Navarre Subject: Re: Menlo Park Meeting Date: Sun, 21 Dec 1997 19:49:58 -0800 (PST) On Sun, 21 Dec 1997, Charlie Rond wrote: > Ken, > Thank you so much for chronicling the meeting for the rest of us who wanted > to be there but couldn't! Though we are out here in the boonies, you made > us feel a part of the get together. I had to leave out a lot of the "really good stuff" just because of bandwidth. One small digression... It was an excellent experience to see Edward's face when Ted got up to share a few slide overlays from the seismo sites in and around Peekskill, New York where both he and Ted worked several years apart. Edward showed us on Ted's slides where he grew up, went to school, (I'll omit the location of his first date overlookign the Hudson...) and later worked. Syncronicity... That was the byword of the day between Ted and Edward. Seems as if their personal lives were intertwined well before they ever met... Doncha just love those "coincidences! Yep. We all had a good time! Ken _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ken Navarre Subject: Re: Menlo Park Meeting Date: Sun, 21 Dec 1997 19:56:02 -0800 (PST) On Sun, 21 Dec 1997, Norman Davis WB6SHI wrote: > Sounds like a realy great time. Will have to try and make the next one. I > was wondering if anyone is working on a a/d interface that would work on a > cheap lap top. It would be good for both low power consumption and and > portability. The cheapest a/d right now is the R/S or dataq modual but only > two channel I haven't had the opportunity to play with either of the units that you mentioned, Norman. I'm tinkering with a single channel 12 bit A/D that plugs into the parallel port. Got it from the new a year or so ago. It's a really tiny little convertor that is the size of a 25 pin connector. Manufactured by ADNAV Elect. in Texas. Jerry Hammes mentioned that he got one as a "kit" that is a 16 bit version. I got mine for $60 and it included some software that is written in QBASIC and is easily modified for multiple lines of display. I use it when I go to Mammoth and don't want to lug the minitower with me. One problem that I have is that I haven't yet got the software to save the file. It is just for real time monitoring. For the saved stuff I still need to rely on SDR at the home station. If I can get my programming skills up I'll have it saving files in the PSN format but please don't hold your breath! :( Ken _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ken Navarre Subject: Re: Menlo Park Meeting Date: Sun, 21 Dec 1997 19:59:09 -0800 (PST) On Sun, 21 Dec 1997, S-T Morrissey wrote: [snip] > I also want to thank Sam Gazdik for putting up my AGU poster > on the homemade broadband leaf spring vertical. Oh yeah! We all loved the innovation. As a matter of fact I now have a brand new drywall knife sitting in front of me (much to the dismay of my significant other! She *knows* where this is going to lead...) Thanks for providing the material for Sam to bring and share! Hope you can make the next meeting! Ken _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ken Navarre Subject: Re: Menlo Park Meeting Date: Sun, 21 Dec 1997 20:01:19 -0800 (PST) On Sun, 21 Dec 1997, Karl Cunningham asked: > Were any group pictures taken that could be scanned and put up for the rest > of us to see? Yeah. Steve Hammond documented the event. Even the parts where we had cheeze "strings" hanging from our mouths from the pizza. I shre how he edits them before he posts them!!! :( He will give Larry some of the better ones for sharing on the site. Ken _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: large sth pacific quake Date: Mon, 22 Dec 1997 16:05:38 +1200 hi all, a large sth pac event recorded at recorded 0214 UTC 22 12 97 usgs servers are out AGAIN i dont yet know how big or where picking ~6.5 and between kermadec to fiji reg maybe greater vanuatu area large p arrival very small S arrival Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Marnie Gannon Subject: large south pacific Date: Sun, 21 Dec 1997 21:15:02 -0700 Dave, From NEIC list: 97/12/22 02:05:49 5.54S 147.77E 179.7 6.7Ms A E NEW GUINEA REG., P.N.G. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Clark Wockner Subject: Re: large sth pacific quake Date: Sun, 21 Dec 1997 22:25:21 -0800 David A. Nelson wrote: > > hi all, > a large sth pac event recorded at recorded 0214 UTC 22 12 97 > > usgs servers are out AGAIN i dont yet know how big or where > > picking ~6.5 and between kermadec to fiji reg maybe greater > vanuatu area > > large p arrival very small S arrival > > Dave > > Co-ordinator: > New Zealand > Public Seismic Network > Dave A. Nelson ZL4TBN > 24 Jensen St., > Green Is., Dunedin, > South Is.. New Zealand. > > http://psn.quake.net/dave/home.htm > > IF there indeed are other parallel universes... I can now rest in the > knowledge, that in at least one of them, I am filthy rich and drive a red > Ferrari > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L Hi David: Yo mentioned in your post about servers being down. try this one. It works when others don't. http://www.eas.slu.edu/cgi-bin/finger?quake@................. Later, Clark _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: large south pacific Date: Mon, 22 Dec 1997 16:26:13 +1200 thanks marnie all the main servers are down even tne inline seismograph servers its Mw must be up in the 7.5 region as the ampl. I have is very large for a Ms 6.7 at that distance tnx again Dave At 09:15 PM 12/21/97 -0700, you wrote: >Dave, > >>From NEIC list: > >97/12/22 02:05:49 5.54S 147.77E 179.7 6.7Ms A E NEW GUINEA REG., >P.N.G. > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: vertical broadband Date: Sun, 21 Dec 1997 23:06:08 -0600 (CST) Jim. Here is a brief description of the broadband vertical leaf-spring seis: THe boom is horizontal, about 18 inches long, with crossed flexure hinges at one end attaching it to an upright support about 6 " high. The leaf spring is 12 " x 3", but is bent in a semicircle under the boom, with one end pressing on the base (through flexures), and the upper end pressing on the under side of the boom, about 3" from the hinges. The mass on the free end of the boom is adjusted so that the boom is balanced. The feedback transducer (speaker coil) is also mounted on the end of the boom. The natural mechanical period is 2 to 4 seconds, depending on the effectiv e mass (about 0.5kg) and other parameters. With feedback, the effective period can be very long, from 20 to gt. 600 seconds, and is totally controlled by the triple feedback from the displacement transducer. The reason a leaf spring is preferred for broadband instruments is that with their flat response from eg. 30 hz to 90 seconds (the present configuration of the prototype in my basement here), mechanical resonances show up in the output, and coil springs have many modes of mechanical ringing in the 1 to 50 hz range; lateral resonances actually shorten the coil spring, raisinbg the mass, causing a long bump in the data. A leaf spring has very high resonances, like several hundred hz, effectively avoiding the problem, and they have no lateral resonances. Hopefully more detailed info on the seis will show up soon on a web page near you. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: drywall knife! Date: Sun, 21 Dec 1997 23:09:23 -0600 (CST) Ken, Be careful there; a student of ours went out and bought his to start on his seis, but his landlord saw it and asked him to help with repairs to the walls of his residence. So now he has to make sure he doesn't get plaster in his seis! Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: large sth pacific quake Date: Mon, 22 Dec 1997 17:18:01 +1200 To leave this list email listserver@............. with the body of the >> message: leave PSN-L >Hi David: >Yo mentioned in your post about servers being down. try this one. It >works when others don't. >http://www.eas.slu.edu/cgi-bin/finger?quake@................. > Later, Clark thanks Ckark didnt know about that one BTW it has been given Mw 7.1 180 km deep Ms 6.7 thanks to all post file soon to events list Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: Re: vertical broadband Date: Mon, 22 Dec 1997 02:51:30 EST Thanks very very much for your explanation. I am going to experiment with your design during the holiday period. I'll let you know how I do. I hope you and your family have a great and safe holiday season. Again Thanks very much. Jim Allen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: large south pacific (Mw 7.1) Date: Mon, 22 Dec 1997 07:26:19 -0700 Here is Jascha Polet's CMC: Subject: CMT Mw=7.1 EASTERN NEW GUINEA REG., P.N.G. Date: Sun, 21 Dec 1997 20:30:15 -0800 (PST) From: Jascha Polet To: autocmtlist@............... General region : EASTERN NEW GUINEA REG., P.N.G. surface waves (3.0,3.5,7,7.5 mHz) Stations used : COR KIP KONO NWAO PAB TUC Origin time: 1997 356 2 5 49 Original location (lat,lon,depth) : -5.50000 147.800 180 Moment tensor (x1.e26 dyncm) : Mrr : -0.103607 Mtt : -4.706806 Mff : 4.810413 Mrt : 4.097936 Mrf : 1.400747 Mtf : -0.208536 T-axis: moment= 5.282 plunge= 19.409 azimuth= 277.113 N-axis: moment= 1.890 plunge= 52.431 azimuth= 34.372 P-axis: moment= -7.172 plunge= 30.744 azimuth= 175.016 best double couple: Mo= 6.227(x1.e26 dyncm) Mw=7.1 tau= 10.2 nodal planes (strike/dip/slip): 223.91/ 82.73/-36.96 319.35/ 53.38/-170.93 Centroid location : -5.554 147.787 160.701 Centroid time : 7.787 Variance reduction (%) : 85 *********** **** **** ***oo-----------------*** **-----oooooo------------oo** **-----------oooo-------ooo--** *----------------ooo---oo-------* *-------------------oooo----------* **------------------oooooo---------** *-----------------ooo----oo---------* **--T-------------oo-------oo--------** **--------------ooo+ -oo-------** **------------ooo oo------** *-----------oo oo-----* **--------oo o ---** *------ oo o -* *--- oo oo * ** oo oo** **o P o** *** *** **** **** *********** -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Re: a/d interface Date: Mon, 22 Dec 1997 07:24:02 At 02:29 PM 12/21/97 -0700, you wrote: >At 08:03 AM 12/21/97, you wrote: >>I was wondering if anyone is working on a a/d interface that would work >>on a cheap lap top. It would be good for both low power consumption and >>portability. > >I think what you are looking for was in the Oct 23 issue of EDN magazine. >It is an 8 chan, 12 bit A/D that plugs into the Par port on a PC (laptop). >Uses the ultra-low power MAX147 chip and a MAX872 to power it. The 12 bit >would most likely be suited to a portable since set-up, adjustment, temp >control and everything else that affects a seismometer would be just noise >in a 16 bit system. And the software is written and in the EDN web site. > >The library should have a copy, if not let me know and I'll fax you a copy. >If Santa comes through, I'll scan it and e-mail you a copy! > >Darrell >WA7DSV I have built a a/d converter based on the max 187 chip but the big rub is will it work with sdr. I don't think any of the rs232 or parallel port converters have drivers for sdr. Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Re: Menlo Park Meeting Date: Mon, 22 Dec 1997 07:37:39 If I can get my programming skills up I'll have >it saving files in the PSN format but please don't hold your breath! :( > Ken I haven't looked at the sdr format. Is it a text dump or in binary, and where can I get the tech data on the format. Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Dennis Eckert" Subject: Re: a/d interface Date: Mon, 22 Dec 1997 09:33:33 -0800 Has anyone tried the DATAQ A/D unit that Radio Shack's mail-order company is selling for $99? Known as the DI-150. It is 2-channels, 12-bit resolution, and includes Win95 software. Know it is only 2 channels but seems like DATAQ has a pretty good reputation with app notes and additional software at their web site: www.dataq.com Specs in RS catalog also say: software allows recording of data to hard drive, plus viewing it in real-time on our monitors in a "selectable oscilloscope-like or chart-recorder-type display." 0-5 volts, 0-10 V or +5 input ranges; gains of 1 and 100. Includes Plug-and-Play serial interface, software, serial cable and, of course, documentation. DATAQ sells essentially the same unit for the same price. "The DI-150 is an improved version of the DI-190. The DI-150 supports (2) thermistors, the DI-190 does not. The DI-150 has (2) gain settings, the DI-190 is fixed at (1). Otherwise they are both the same. "We can take your order for either unit or you can place an order at your local Radio Shack (for the DI-150 only)......" Dennis Eckert KB7ST (Amateur Radio Operator) Flies Standard Cirrus sailplane (SV) In Western & Eastern Washington ICQ 4324132 -----Original Message----- From: barry lotz To: PSN-L Mailing List Date: Sunday, December 21, 1997 2:07 PM Subject: Re: a/d interface >Hi > In the Dec Circuit Cellar magazine there was an outfit that had a 8 >chan 12 bit plug in for the parallel port. ADNAV Electronics. >www.tgn.net/~adnav . I haven't checked out the web site but they the >adaptor is $99. > Barry > >Darrell Collins wrote: >> >> At 08:03 AM 12/21/97, you wrote: >> >I was wondering if anyone is working on a a/d interface that would work >> >on a cheap lap top. It would be good for both low power consumption and >> >portability. >> >> I think what you are looking for was in the Oct 23 issue of EDN magazine. >> It is an 8 chan, 12 bit A/D that plugs into the Par port on a PC (laptop). >> Uses the ultra-low power MAX147 chip and a MAX872 to power it. The 12 bit >> would most likely be suited to a portable since set-up, adjustment, temp >> control and everything else that affects a seismometer would be just noise >> in a 16 bit system. And the software is written and in the EDN web site. >> >> The library should have a copy, if not let me know and I'll fax you a copy. > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Dennis Eckert" Subject: A/D intro Date: Mon, 22 Dec 1997 09:53:45 -0800 This page at DATAQ offers a nice introduction to data acquisition issues. http://www.dataq.com/sensors.htm begin 666 Sensors.url M6TEN=&5R;F5T4VAO Subject: VBB feedback Date: Mon, 22 Dec 1997 17:28:54 -0600 (CST) Jim, Thanks for your interest in the broadband sensor feedback analysis. I use MATHCAD for the mathematical modeling; I assume that SPICE will do as well; I looked it at, but couldn't afford it. Unfortunately, I do all this work here at home, since my work at the University is essentially "interrupt driven" with the effort of building and operating instrumentation for seismic networks. But I don't have any ready means of exporting the MATHCAD, AUTOCAD, and .WPS files to the UNIX system at work, ...yet. However, because of the considerable interest in it, I have "hand-written" the transfer function so it can be exported as a .txt file: The transfer function of a triple feedback broadband seismometer: The mechanical sensor values: r = displacement transducer constant, volts/meter (range: 80 - 1000 V/m) Td = Displacement transducer time constant (less than 0.01 sec) Gn = force transducer constant, newtons/amp (range 10 -100 N/A) Rf = force transducer resistance, ohms (range 5 -500 ohms) M = sensor effective mass, kg To = Mechanical free period of the sensor, seconds (range 1 -15 sec.) The Electronic feedback parameters: C = feedback capacitor, farads (range 1 - 36 uf) Rp = Proportional feedback resistor, ohms (range 100 - 1000k) TI = Integrator time constant, seconds (range 20 - 1000 seconds) RI = Integrator feedback resistor, ohms (range 200 - 2000k) (C and Rp are connected from the displacement transducer output amp to the feedback coil; RI is connected from the integrator output to the feedback coil, at the same summing point as C and Rp) Actual (or sample) values for a 90 second instrument: r = 370000 volts/meter; Td = 0.02 sec.; Gn = 12.65 Newtons/Ampere; Rf = 8.5 ohms; M = 0.5kg; To = 2 seconds; C = 24 ufarad; Rp = 561k ohms; TI = 80.4 seconds; RI = 107k ohms. (The following mathematical expressions are in ascii notation so that they can be exported by kermit, email,etc.) (If you want the MATHCAD document, email a FAX number). b: In the transfer function, "G" is actually conventional "G" / M. G = Gn/M (m/sec**2/amp Also, the angular frequrncy is Sw0 = 2*pi/To c: Expression for effective free period: controlled only by electronic components. Tn = 2*pi*(C*RI*TI)**-2 d: Expression for effective damping is determined by electronic components and the mechanical free period. If Rp is turned off, the system is effectively under damped, and will oscillate at Tn. zeta = 0.5(1/Rp + Sw0**2/R*G)*(TI*RI/C)**-2 With the sample values, Tn = 90seconds, zeta = 0.847 e: Complete transfer function: a fourth order expression. (Si is complex, = j*wi, w being omega, i being a subscript) Output voltage per Acceleration: Ai = k*[Si*(1 + Si*n)/Si**4*a + Si**3*b + Si**2 + Si*c +d] Where: k = 1/G*C n = C*Rf a = Rf/r*G b = 1/r*G*C c = [Sw0**2/r*G*C + 1/C*Rp] d = 1/C*RI/TI The Voltage per Velocity is simply [Ai * Si], in volts/meter/second With the sample values, the velocity output voltage is 1647 V/m/s, flat from 64 seconds to 33 hz +-2db. I hope that this satisfies your interest and allows you to plug the expressions into SPICE. If you want a copy of the MATHCAD document, send me a FAX number. Regards, and Merry Christmas, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Geo-magnetic Field Disturbance Noted Date: Mon, 22 Dec 1997 19:05:55 -0800 (PST) Hello All: Yet another significant change in the geo-magnetic field strength was noticed over this past weekend. The location of my magnetometer is approx. 6 miles west of Fontana, CA. It is the second time in the past two weeks that a major change was observed. It seems that the time stamp was not valid because of a malfunction. So, I can only give the time of occurance between Friday 12/19/97 5:00pm PST and Monday 12/22/97 7am PST. Did any more of those solar flares happen in that time window? Frank Condon mail to:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana and Mammoth Lakes" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: a/d interface Date: Mon, 22 Dec 1997 20:18:19 -0700 At 07:24 AM 12/22/97, Norman Davis wrote: > I have built a a/d converter based on the max 187 chip but the big rub is >will it work with sdr. I don't think any of the rs232 or parallel port >converters have drivers for sdr. > Unfortunately not. SDR was written around a 1 millisecond interrupt produced by the A/D card. It also needs a very fast A/D converter chip so that several channels can be sampled at a high sample rate. It would take a MAJOR rewrite of SDR to use the RS232 or the printer port. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: PSN format Date: Mon, 22 Dec 1997 20:51:30 -0700 At 07:37 AM 12/22/97, Norman Davis wrote: > I haven't looked at the sdr format. Is it a text dump or in binary, and >where can I get the tech data on the format. The PSN event file format is binary. The format is described in the following text file: http://psn.quake.net/info/format.txt -Larry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Feedback Coil Date: Mon, 22 Dec 1997 10:45:32 -0800 Hi All I have been wondering about the feedback coil used in a force-balance system. In a Lehman, where the coil is used as a sensor, more turns is better. In a solenoid ,for the same spool size more turns of a finer wire produces a higher resistance and lower current whereas fewer turns gives higher current but is the field strength higher? Ie, is there an optimum coil # of turns for a given wire size to generate the highest force output? Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: Menlo Park Meeting Date: Mon, 22 Dec 1997 22:41:28 -0700 Ken Navarre- Thank you very much for the wonderful reporting job on the PSN meeting. I have not been able to read it all in detail because my old microVAX email server software blew up while I was on the road in California, and the last week of email, particularly that of the weekend (wouldn't you know) is in shambles. I hope to sort out my situation by Xmas, and if I don't, there are the PSN RWC archives. Doing the documentation is always my weakest point, and so I am very grateful for your writing. Thank you and thank you all who attended and thank you those who read about it and responded. -Edward _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Al Allworth" Subject: Re: Feedback Coil Date: Mon, 22 Dec 1997 23:03:46 -0800 -----Original Message----- From: barry lotz To: psn list Date: Monday, December 22, 1997 9:46 PM Subject: Feedback Coil >Hi All > I have been wondering about the feedback coil used in a force-balance >system. In a Lehman, where the coil is used as a sensor, more turns is >better. In a solenoid ,for the same spool size more turns of a finer >wire produces a higher resistance and lower current whereas fewer turns The magnetic field strength is the function of: Amperes X Turns. (That is for the same spool size.) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: Feedback Coil Date: Tue, 23 Dec 1997 06:17:55 -0600 Al Allworth wrote: > > -----Original Message----- > From: barry lotz > To: psn list > Date: Monday, December 22, 1997 9:46 PM > Subject: Feedback Coil > > >Hi All > > I have been wondering about the feedback coil used in a force-balance > >system. In a Lehman, where the coil is used as a sensor, more turns is > >better. In a solenoid ,for the same spool size more turns of a finer > >wire produces a higher resistance and lower current whereas fewer turns > > The magnetic field strength is the function of: Amperes X Turns. (That is > for the same spool size.) > > Two things need to be considered for the feedback coil. One is matching the current/voltage requirements of the driving circuit and the second is the packing factor of the wire size chosen. If the driving circuit can be designed around the current/voltage requirements of the coil then all that is necessary is to find the wire size that will give you the most ampereturns for the coil size needed. In high power applications square wire is sometimes used to get more ampturns in the same space. The other thing to consider is the magnetic field strength throught the coil. The stronger the field the stronger the force for a given coil. Having a complete magnetic path except for the gap the coil sits in and keeping the gap as small as possible both contrubute to a stronger field in the gap. These same considerations work for a sense coil also. Since the power delivered by the coil for a given movement is the important factor. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: Feedback Coil Date: Tue, 23 Dec 1997 11:49:23 -0600 (CST) Jim, Barry, et al, Here is some helpful info re. feedback coils: For a feedback seismometer the DC resistance of the coil is one of the terms of the transfer function, and if it is too large w.r.t other parameters, the function is unstable. This is why efforts to use many commercial seismometers for feedback configurations will not work, because their coils have very high resistances for electronic applications. IN fact, the signal coil of some sensors cannot even be used for damping. In most commercial fedback seismometers, the force coils have resistances of 50 to 200 ohms, and generator constants of between 20 and 80 Newtons/Ampere. The highest resistance I have been able to use in an experimental feedback configuration is the 500 ohm coil of the classic Sprengnether-Columbia long period (15 to 30 second) seis ( model S5000) used in the WWNSS (World Wide Network of Standard Seismograph Stations, of which over 200 were installed in the 60's); (the horizontal seismometer is the "predecessor" of the "Lehman" design.) This large sensor has an 11 kg mass and a large generator constant of 83 N/A, so it works as a broadband at an effective period of 600 seconds (recording solid earth normal modes). One way to estimate the the constant of a coil is to count the turns and determine the strength B of the magnetic field in gauss. Estimate the length L of the winding IN CM by multiplying the # of turns by the mean circumference. Then G = B * L *10 **-6 N/A. For the 8-ohm stereo speaker I use, there are 162 turns at a mean diameter of 3.95cm, and the flyer says the field is 7500 gauss, so the constant is 15.08 N/A. When I determine the constant by force balance, 1 gram is balanced by 0.775ma, for a constant of 12.664 N/A, which probably means that not all the winding is within the magnetic field, which is the case. Large (10" or greater) stereo speakers make great feedback coils if the seismometer is constructed so as to maintain the minimal clearance between the coil and the annular gap between the poles of the large (20 ounce) magnet. Regards, and Merry Christmas Sean-THomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: bob@................. (Bob Hammond (USGS-AVO Geophysicist)) Subject: new URL for the Alaska Public Seismic Network (and other changes) Date: Tue, 23 Dec 1997 10:24:55 -0900 Hi all, I've had to move my APSN webpage to: www2.polarnet.com/~whammond Also, I'm working with another elementary school (Weller Elementary, east of Fairbanks) to install a short-period sensor with EMON and QUAKEVU. It will probably be operational in early January. The Grayling School station (GRY) has probably bit the dust due to a lack of interest. My own station has changed. I'm now running Larry's SDR with his 12-bit A/D board. This winter's project is to get the Geotech 10-second instrument on a concrete pier under the house. Glad to see the N. California meeting so well attended. When do we get to hear more about EMON? Merry Christmas to all, Bob Hammond APSN Fairbanks, AK _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Walt Williams" Subject: Geo-magnetic Field Disturbance Noted Date: Tue, 23 Dec 1997 11:39:00 +0000 Hello Frank, Please see: gopher://proton.sec.noaa.gov:70/11/plots The SEL / NOAA plot gifs as you probably know are coded, YrMoDy, i.e., 970101 := 1997, Jan, 01 and see: http://www.pfrr.alaska.edu/~pfrr/DATA/MR-1997.HTM for interesting magnetosphere and ionospheric info. Best Regards, Walt Williams, 97.12.23 Woodland Hills, Ca., (LA suburb) USA dfheli@.............. http://www.pacificnet.net/~dfheli p.s. Best wishes for all in this holiday season. ====================================== ------- Forwarded Message Follows ------- Date: Mon, 22 Dec 1997 19:05:55 -0800 (PST) To: psn-l@............. From: frankcnd@.......... (Frank Condon) Subject: Geo-magnetic Field Disturbance Noted Reply-to: PSN-L Mailing List Hello All: Yet another significant change in the geo-magnetic field strength was noticed over this past weekend. The location of my magnetometer is approx. 6 miles west of Fontana, CA. It is the second time in the past two weeks that a major change was observed. It seems that the time stamp was not valid because of a malfunction. So, I can only give the time of occurance between Friday 12/19/97 5:00pm PST and Monday 12/22/97 7am PST. Did any more of those solar flares happen in that time window? Frank Condon mail to:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana and Mammoth Lakes" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Warner Lindholm Subject: Re: VBB feedback Date: Tue, 23 Dec 1997 13:55:18 -0800 (PST) Is there anyone on the list beside me having trouble with S-T Morrissey's transfer function? This is wonderful stuff that I'd like to run through Matlab but there are what appear to be contradictions, ambiguities and omissions. I hope this language is not misconstrued because I mean it to be taken in the kindest way. I'm puzzled about r, the displacement transducer constant. The range is given as 80 - 1000 V/m but the actual value reported is 370000 volts/meter. Is this the correct value or a typo? In 'c; Expression for effective free period' Tn is given as '2*pi*(C*RI*TI)**-2'. Should not this be '2*pi*sqrt(C*RI*TI)' which gives the 90 second value reported. In the expression for zeta an undefined variable, R, is used but plugging the various R parameters did not yield the reported value for zeta. Maybe the problem is with the '(TI*RI/C)**-2' construct? Perhaps 'zeta = 0.5*(1/Rp + Sw0**2/RG)*sqrt(TI*RI/C)' was meant instead? How about the dimensions of zeta? I wasn't smart enough to figure out how to make the expression a dimensionless number but as it appears on the page things don't seem to add up. I'm sure I've misunderstood the expression for the transfer function because the way it's written leaves an Si term that can be reduced. Perhaps some of you out there can clarify things for me. I'd like to build one of these things. I especially want to thank S-T Morrissey for sharing his work with us and I predict we'll soon be seeing a lot of S-T Morrissey seismometers out there! _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: VBB feedback Date: Tue, 23 Dec 1997 16:26:10 -0600 Warner Lindholm wrote: > > Is there anyone on the list beside me having trouble with S-T Morrissey's > transfer function? This is wonderful stuff that I'd like to run through > Matlab but there are what appear to be contradictions, ambiguities and > omissions. I hope this language is not misconstrued because I mean it > to be taken in the kindest way. > >Warner, Sean sent me this correction to the transfer function. I don't think it got copied to the list. I haven't had the time yet to look at the equations in detail so I can't make any other comments. Jim, I just noticed an ambiguity in the long-hand version of the transfer function that might not be noticed by someone not familiar with such expressions; brackets now separate the numerator and denominator. The transfer function of a triple feedback broadband seismometer: Ai = k*{[Si*(1 + Si*n)]/[ Si**4*a + Si**3*b + Si**2 + Si*c +d]} Regards, Sean-Thomas -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: VBB feedback corrections Date: Tue, 23 Dec 1997 17:28:53 -0600 (CST) Warner et. al, Thanks for the feedback on the equations. I sort of stuck my neck out in trying to write them in ascii, which I really never do, and probably got confused with the eqn constructs of troff in UNIX or other archaic constructs. The error here is that I wrote the square root as **-2 rather than **1/2. You suggested "sqrt" as in fortran and C. I also noticed a parsing error in the laplacian, which I corrected, but as Karl noted, didn't send to the PSN list. The corrected equations should read: The transfer function of a triple feedback broadband seismometer: G = Gn/M (m/sec**2/amp Tn = 2*pi*(C*RI*TI)**1/2 zeta = 0.5[1/Rp + (Sw0**2/R*G)]*(TI*RI/C)**1/2 Ai = k*{[Si*(1 + Si*n)]/[ Si**4*a + Si**3*b + Si**2 + Si*c +d]} Where: k = 1/G*C n = C*Rf a = Rf/r*G b = 1/r*G*C c = [Sw0**2/r*G*C + 1/C*Rp] d = 1/C*RI/TI Of course, you can always send me a FAX number or a self-addressed stamped envelope, and I will send you the actual MATHCAD document. And your observation on the discrepancy in the value of the displacement transducer output is correct: the output range is usually in mv/micron, or volts/millimeter; but the function needs volts/meter. BUT, I omitted the detail that my 37mv/micron transducer has a 10 x amplifier after it, for a gain of 370 volts/mm, which converts to the listed value of 370 000 volts/meter. The last value of the r= line should read "V/mm". Thanks for your interest, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: VBB feedback corrections: Date: Tue, 23 Dec 1997 17:46:13 -0600 (CST) Warner, I forgot another detail that you noticed: the R in the damping equation should be "r": The correct equations are: (and please discard previous editions) The transfer function of a triple feedback broadband seismometer: : G = Gn/M (m/sec**2/amp Tn = 2*pi*(C*RI*TI)**1/2 zeta = 0.5[1/Rp + (Sw0**2/(r*G))]*(TI*RI/C)**1/2 Ai = k*{[Si*(1 + Si*n)]/[ Si**4*a + Si**3*b + Si**2 + Si*c +d]} Where: k = 1/(G*C) n = C*Rf a = Rf/(r*G) b = 1/(r*G*C) c = [Sw0**2/(r*G*C) + 1/(C*Rp)] d = 1/(C*RI*TI) Hopefully these will translate back to the proper function. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: VBB feedback & feedback coil Date: Tue, 23 Dec 1997 07:39:10 -0800 Al,Jim & Sean Thomas Thanks for the input. I'll ponder the coil turn/current issue. Sean - I am unsure about your VBB feedback component flow. Could you briefly explain the component sequence. I understood the displacement output is fed thru a parallel resistor & cap into the coil. Also the displacement output is fed thru an integrator into the coil also parallel to the resistor and cap. Is there a summing amp just before the coil? Where is the output measured? I will send you an envelope for a copy of your paper. I can wait if 1 picture is worth 1000 words. Safe Holidays to all Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Warner Lindholm Subject: Re: VBB feedback corrections: Date: Tue, 23 Dec 1997 19:36:17 -0800 (PST) Sean-Thomas, Thanks for the clarification. With Matlab I'm now able to see just how flat your seismometer is. Pretty darned impressive I must say! Now let me ask you this; having the transfer function could I now calculate the impulse response to derive coefficients for a digital filter so I could do the signal processing in software? Wouldn't that be a hoot! -Warner _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: new URL for the Alaska Public Seismic Network (and other Date: Wed, 24 Dec 1997 15:47:15 +1200 noted bob, will update the psn database soon thankyou merry xmas Dave At 10:24 AM 12/23/97 -0900, you wrote: >Hi all, >I've had to move my APSN webpage to: www2.polarnet.com/~whammond >Also, I'm working with another elementary school (Weller Elementary, east of Fairbanks) to >Merry Christmas to all, >Bob Hammond >APSN >Fairbanks, AK Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Cristiano Subject: Re: VBB feedback corrections: Date: Tue, 23 Dec 1997 20:57:15 -0800 S-T Morrissey wrote: > G = Gn/M (m/sec**2/amp > Tn = 2*pi*(C*RI*TI)**1/2 > zeta = 0.5[1/Rp + (Sw0**2/(r*G))]*(TI*RI/C)**1/2 > Ai = k*{[Si*(1 + Si*n)]/[ Si**4*a + Si**3*b + Si**2 + Si*c +d]} > > Where: k = 1/(G*C) > n = C*Rf > a = Rf/(r*G) > b = 1/(r*G*C) > c = [Sw0**2/(r*G*C) + 1/(C*Rp)] > d = 1/(C*RI*TI) Geeeeezzzzz, OK, I give. What you're saying is that the dirivitive is equal to the inverse of the exponential argument squared by the magnitude of the flux parameter, taken to the -.26153 power multiplied by pi? I'll have to do some more work on my transform functions. Jim cristiano@........... P.S. No wonder I can't get the #@&$*~!! thing to work! _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: [Fwd: Purchasing Seismograph] Date: Tue, 23 Dec 1997 23:02:55 -0700 -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". Dear Sir, How do I go about obtaining the manufacturer and purchase price of a PADS? My Email address is pinecone@............. John Paul Martin From: S-T Morrissey Subject: Re: VBB feedback & feedback coil Date: Wed, 24 Dec 1997 00:32:49 -0600 (CST) Barry, Here is a primitive block diagram of the VBB feedback: ...... in ascii! Displacement|-------->> VBB output, V/M/sec -->> to recorder Transducer | (W. X10 amp)| |--->> Proportional Resistor (Rf) ----> | | | |--->> Differential Capacitor (C) ----> | | | |-->> Integrator (TI seconds) | output: | | | Feedback |->> Integrator Resistor RI --> | Coil | -->> )--( )--( )--( )--( circuit common | -->> )--( | |----| |MASS| |----| Notes: 1. The displacement transducer output is Volts/meter when the feedback is not connected, as when the mass/boom needs to be centered. WHEN and ONLY WHEN the feedback is connected, the SAME output is the VBB signal, in volts/meter/second. 2. No amplifier or buffer is used between the summing junction of Rf, C, and RI. All three MUST be connected directly to the feedback coil, whose other end is the circuit common. The feedback coil is installed on the free end of the boom near the mass. 3. Additional amplification may be needed for the VBB output; I use another X20 gain to get the background microseisms up to a range of 1 to 5 mv p-p. Commercial sensors have a variety of such "line drivers". 4. The integrator (which by the way, is unity gain) output can be metered as a "mass position" output to determine if the feedback is within operating range; I use a cheap +,- 5 volt analog meter. The same meter can be switched to the VBB output to monitor recentering of the mass with the feedback off. This is more useful for making adjustments than the integrator output, which is delayed by TI. Hopefully this will clarify the simplicity of the VBB configuration. Merry Christmas, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: VBB block diag, Date: Wed, 24 Dec 1997 00:56:06 -0600 (CST) Barry, When the mail came back, it trashed the block diagram because of the tabs: Here is the same w/o tabs (at the risk of filling up a lot of PSN mboxes) Here is a primitive block diagram of the VBB feedback: ...... in ascii! Displacement|----->> VBB output, V/M/sec -->> to recorder Transducer | (W. X10 amp)| |->> Proportional Resistor (Rf) --> | | | |->> Differential Capacitor (C) --> | | | |->> Integrator (TI seconds) | output: | | | Feedback |->> Integrator Resistor RI ---> | Coil | -->> )--( )--( )--( )--( circuit common | -->> )--( | |----| |MASS| |----| Notes: 1. The displacement transducer output is Volts/meter when the feedback is not connected, as when the mass/boom needs to be centered. WHEN and ONLY WHEN the feedback is connected, the SAME output is the VBB signal, in volts/meter/second. 2. No amplifier or buffer is used between the summing junction of Rf, C, and RI. All three MUST be connected directly to the feedback coil, whose other end is the circuit common. The feedback coil is installed on the free end of the boom near the mass. 3. Additional amplification may be needed for the VBB output; I use another X20 gain to get the background microseisms up to a range of 1 to 5 mv p-p. Commercial sensors have a variety of such "line drivers". 4. The integrator (which by the way, is unity gain) output can be metered as a "mass position" output to determine if the feedback is within operating range; I use a cheap +,- 5 volt analog meter. The same meter can be switched to the VBB output to monitor recentering of the mass with the feedback off. This is more useful for making adjustments than the integrator output, which is delayed by TI. Hopefully this will clarify the simplicity of the VBB configuration. again, Merry Christmas Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: Public Seismic Network meeting at USGS, Menlo Park Date: Wed, 24 Dec 1997 00:00:02 -0700 Kristine & Carl- Thank you very much for making the necessary arrangements that allowed the Public Seismic Network (PSN) to use the Building 8 Conference Room for the Northern California PSN meeting on Saturday, 20 Dec 1997. Eleven members of the PSN attended the meeting, and I believe it was quite successful. I wish you both Happy Holidays and a Happy New Year. -Edward Kristine Estrada wrote: > > Carl/Ed: > > I have alerted the Safety/Security office of this Saturday meeting in Building 8, > Room 8111; the guard will be notified. I penciled the meeting in for "all day". > Let me know the time your group plans to arrive and depart. > Thanks, > Kristine, x4140 > > Carl Mortensen wrote: > > > Ed - > > > > Because of the construction on building 3, building 8 has the > > largest conference room on campus, so it has been transferred to the OPS > > Division to administer. The person who takes the reservations is : > > > > name: Estrada, Kristine R > > email: kestrada@........ (kestrada@............ > > phone: 650-329-4140 > > address: 345 Middlefield Road, MS 225 > > : Menlo Park, CA 94025 > > office_location: 01, Room 117 > > department: OPS > > > > I've cc'd her on this message so that she can make the reservations > > if it's available. > > > > Regards, > > > > Carl > > > > >Carl- > > > Members of the Public Seismic Network (PSN) from the San Francisco Bay > > >Area are planning to hold a meeting on Saturday, 20 December 1997, and > > >John Lahr suggested that I contact you about the possibility of having > > >that meeting in Building 8 of USGS, Menlo Park. Several years ago, in > > >1993 I believe, Joe Sena and Jerry Eaton sponsored a similar PSN meeting > > >that was held in Building 8 on a Saturday so that PSN members who worked > > >during the week would be able to attend. > > > We will be presenting a PSN poster at AGU on Friday, 12 Dec, and I will > > >be in the Bay Area to work with the PSN the following week (14-20 dec) > > >and to attend on the PSN meeting that Saturday. So, I will be available > > >as the USGS representative to be responsible for the visitors. I > > >anticipate that there would be 10-40 attendees. > > > Please let me know if we may hold the PSN meeting at the USGS, Menlo > > >Park, on Saturday, 20 Dec 1997. > > >-Edward > > > > > >-- > > >Edward Cranswick Tel: 303-273-8609 > > >US Geological Survey, MS 966 Fax: 303-273-8600 > > >PO Box 25046, Federal Center cranswick@........ > > >Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". > > > > ____________________________________________________________________ > > Carl Mortensen e-mail: cmortensen@.................. > > US Geological Survey Phone: 650-329-4856 > > 345 Middlefield Road, MS/977 Fax: 650-329-5163 > > Menlo Park, CA 94025 -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: Public Seismic Network meeting at USGS, Menlo Park Date: Wed, 24 Dec 1997 00:19:15 -0700 To PSN members ... who attended the 20 Dec PSN meeting and/or who have benefitted from Sam Gazdik's display of Sean-Thomas Morrissey's poster at the meeting and/or who feel the Holiday Spirit, I think it would be good for PSN/USGS relations if you would send email to Kristine & Carl of the USGS (see below) thanking them for allowing us to have the PSN meeting at USGS Menlo Park. Happy Holidays and Happy New Year to you and your families all! -Edward > > > name: Estrada, Kristine R > > > email: kestrada@........ (kestrada@............ > > > phone: 650-329-4140 > > > address: 345 Middlefield Road, MS 225 > > > : Menlo Park, CA 94025 > > > office_location: 01, Room 117 > > > department: OPS > > > Carl Mortensen e-mail: cmortensen@.................. > > > US Geological Survey Phone: 650-329-4856 > > > 345 Middlefield Road, MS/977 Fax: 650-329-5163 > > > Menlo Park, CA 94025 Edward Cranswick wrote: > > Kristine & Carl- > Thank you very much for making the necessary arrangements that allowed > the Public Seismic Network (PSN) to use the Building 8 Conference Room > for the Northern California PSN meeting on Saturday, 20 Dec 1997. > Eleven members of the PSN attended the meeting, and I believe it was > quite successful. > I wish you both Happy Holidays and a Happy New Year. > -Edward -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Charlie Rond Subject: Menlo Park Meeting reflections Date: Wed, 24 Dec 1997 05:01:15 -0600 At this time of year, I'm especially thankful for family, good friends and their special gifts. The Menlo Park meeting reminded me of my indebtedness and gratitude to the good friends (most of whom I've never actually met) in the PSN "family". My special thanks to: Edward Cranswick-for "fathering" the PSN, continuing to encourage and educate the rest of us, and for his friendship. Steve Hammond-for "birthing" PSN-Memphis with equipment, support and encouragement. Ted Blank-for his wonderful EMON and Quakeview software, for continued support and development of it, and his readiness to respond to users suggestions and feedback. Larry Cochrane-for invaluable development and production work on his WinQuake and SDR software, the Web, the PSN List, and his good, reliable electronics. Ken Navarre-for past help and for reporting on the recent Menlo Park meeting. Pete Rowe-for his initial amplifier design. Dorothy Darby-for a level of help and constant support that it could never be totally summarized, much less repaid. Jerry Darby-for equipment and help. Ted Smith-for his amazing commitment to keeping us connected and updated through the GeoInfo Net, as well as other help. and for many more, whom I've not singled out. My sincerest wishes for a Happy Holiday season for all of you! Charlie Rond -\/\--Public Seismic Network-Memphis rond@................ (901) 360-0302 [ free BBS ] http://gandlf.ceri.memphis.edu/~rond http://gandlf.ceri.memphis.edu/~rond/psn _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Giovanni Rotta" Subject: from Italy Date: Wed, 24 Dec 1997 13:57:20 +0100 Hi friends !! Merry Christmast and Happy New Year from Italy ! Giovanni Giovanni Rotta rottag@.......... Via F. Pizzigoni, 10 33010 Resia (Udine) Italy Lat. 46.22N Long. 13.18E _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: Re: SEISMIC COIL Date: Wed, 24 Dec 1997 09:57:09 EST Sean-Thomas - Et.All Thank you for the help you have provided to me in the last few days. I am well on my way to constructing my first seismometer which will have features simular to the one you recently developed. Yesterday I purchased a large (3.5 inch X 3.5 inch) horseshoe magnet with a gap of about 1 inch wide X 2 inches deep. For the seismic pickup coil I would like to use one of the speaker coils simular to the one you are using for a feedback coil. Can the coils be used for the seismic coil or do they have a metal core or some other construction that would prohibit there use for this purpose? Again thanks for you help. Jim Allen Cerritos, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Mustafa Erdik Subject: Re: from Istanbul Date: Wed, 24 Dec 1997 14:57:04 +0000 To Public Seismic Network Friends Have a Merry Christmas and a Happy New Year. Mustafa Erdik Mustafa Erdik Professor and Chair, Department of Earthquake Engineering Kandilli Observatory and Earthquake Engineering Bogazici University 81220 Cengelkoy, Istanbul, Turkey e-mail: erdik@..................... earthquake@............... mustafa@.................... Fax: +90.216.308.0163, +90.216.332.1711 Tel: (Bus.) +90.216.332.6560, +90.216.332.9701 (Home) +90.216.339.8633 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Francesco" Subject: R: from Italy Date: Wed, 24 Dec 1997 18:24:33 +0100 Hi. Marry Christmas and happy new year to all. Francesco Nucera - Ancona, Italy. SPERIMENTAL SEISMIC ITALIAN NETWORK _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Francesco" Subject: R: from Istanbul Date: Wed, 24 Dec 1997 18:26:53 +0100 Happy Days for you Francesco Nucera - Ancona, Italy SPERIMENTAL SEISMIC ITALIAN NETWORK _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: SEISMIC COIL Date: Wed, 24 Dec 1997 11:36:36 -0600 (CST) Jim, Here is some info on the speaker coil: Re. using a stereo speaker for the feedback transducer in a broadband seismometer: (A more detailed description will come to a web page near you someday) I use the Radio Shack 10-inch dual coil "sub-woofer" because it has two coils for a total of 8 ohms. (leading to sometimes calling the seismometer a "speakerseis" or the STM-8, which is a name similar to the $15k commercial STS-1). (RS Catalog # 40-1349, can be found on sale for $40). I use both the voice coil AND the 20 ounce magnet. The strength of this large ceramic magnet is listed at 7500 gauss in the annular gap of the coil; this is about 10X stronger than most other magnet configurations. To dismantle the speaker use a sharp Xacto style knife; carefully remove the cone by cutting around the outer edge and around the lower support diaphram. The central dome is also removed. Cut off the leads near the underside of the cone. Very carefully remove the coil assembly: if it gets damaged, it won't fit back into the magnet gap. Then cut away all but the last 2-3" of the cone. I then cut a square notch in both sides of the remaining cone to fit a 1/2h x 3/4"w x 6"l aluminum channel to the coil, carefully fitted so it rests directly on the inside end of the coil, epoxied to both the end of the coil and the base of the cone on both sides. Drill a pattern of mounting holes in the aluminum channel first, though, so it can be mounted to the boom. The coil is formed on a thin aluminum cylinder that has an axial notch so it doesn't damp, but provides heat dissipation. Leave it intact. If you want calibration or compensation coils, wind them (5 to 25 turns) around the base of the cone just above the main voice coil windings, using #36 BELDSOL magnet wire, glued in place, and bring the ends to a handy terminal strip (a 16-pin IC socket upside down) glued inside the Al channel. To prepare the magnet, first tape over the annular gap and the 1/2 inch holes through the pole with heavy tape (like duct); you don't want magnetic filings in the gap. Then cut away the steel cone frame just above the magnet face; I have used metal shears as well as a hacksaw. The hacksaw makes lots of filings that have to be pulled off of all parts of the magnet with sticky tape. I eventually overwrap the outside of the magnet with stretched tape to keep the remaining filings trapped. Remove filings from the annular gap with tape. The magnet can be mounted with a piece of 1/2" aluminum, brass, or stainless threaded rod through the hole in the pole. To use the coil and magnet as the feedback transducer, the boom must be long enough so that the arc of the movement of the coil in the magnet gap allows several millimeters of movement without jamming. I use a boom about 16" long. When installing the magnet under the coil, don't force it, but let it drop into the annular gap as you slide the magnet toward the hinge. Fine position the magnet pole inside the coil so the boom oscillates freely. The air damping of the coil in the gap is appreciable. Always use stainless, aluminum, or brass hardware. Keep the magnet away from your tools,etc., it is a powerful attractor. Regards, and Merry Christmas Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Doug Crice Subject: Re: Fault Creep Date: Wed, 24 Dec 1997 09:48:22 -0800 I spent my formative years measuring fault displacement on the San Andreas system from San Francisco to Palm Springs. We used a Model 2A Geodimeter with a tungsten lamp (this was before lasers) working between mountain tops at night in the period from 1959 to circa 1970. The USGS continued with a similar program afterwards, but I moved out of the earthquake business and never got to hear the end of the story (what was moving where and how much). Is there a more recent report I could order detailing fault slip in California. If anybody cares, I can tell you what was happening then. Doug Crice _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: VBB block diag, Date: Tue, 23 Dec 1997 23:39:19 -0800 Sean Thomas Thanks. I got it. My experimental sensor has all the components arranged in a different configuration. I won't be a problem to rearrange and give your circuit a try. I will have to use a different coil since mine was made with 40 ga wire and mega resistance (>20k to be exact). I thought more turns would be better. I went thru my old physics books and it seems the magnetic field strength is a function of the wire crossectional area and input voltage, but obviously there is a upper limit. The power requirement would be a function of the (wire area)^2. There should be a way to calculate the optimum wire size, given a constant input voltage and spool configuration. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: Re: SEISMIC COIL Date: Wed, 24 Dec 1997 13:40:36 EST Again thank you very very much. Not only has your information been educational but tremendously inspiring. I am going our right now and purchasing one of those speakers from a local surplus source in Los Angeles. Merry Christmas Jim Allen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: Re: SEISMIC COIL Date: Wed, 24 Dec 1997 13:44:24 EST TO: Sean-Thomas Again thank you very much. Not only has your information been educational but tremendously inspiring. I am going ou right now and purchasing one of those speakers from a local surplus source in Los Angeles. Merry Christmas Jim Allen Cerritos, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: coil resistance Date: Wed, 24 Dec 1997 13:20:05 -0600 (CST) Barry, You probably won't be able to use the triple feedback VBB config with a 20K coil. If you notice inthe transfer function, that value (Rf) is a coefficient of the 4-th order term Si**4. When it is large, the configuration is unstable at the short period end, and the seis will actually oscillate. But other feedback configs might work. Merry Christmas, Sean-Thomas .. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "M. Luly" Subject: BurrBorwn A/D Card Questions Date: Wed, 24 Dec 1997 15:25:15 -0500 A friend recently gave me a set of old Burr-Brown I/O cards. While the Analog Output and Digital I/O cards were in the original shrink wrap with= disks & manuals, the Analog input card had been used and the documentatio= n is missing. Here is what I know: + Burr-Brown PCI-20089W-1 + manufactured about 1989 + 16/8 analog input channels + single-ended/differential + 12-bit resolution + programmable gain amplifier + gain=3D1, 10, 100 + up to 32kHz sample rate Burr-Brown no longer lists it on their web site, not even under the discontinued section. Intelligent Instrumentation Products appears to ha= ve manufactured it for Burr-Brown, but they don't list it on their site either. QUESTION: Does any one have experience/documentation for this card? I am= considering programming in either Turbo Pascal V6 (DOS) on a 386SX DOS machine dedicated to data acquisition, or Visual Basic (or maybe Delphi) = on a Pentium machine. But without drivers and/or a manual I'm stuck. Do th= e popular amatuer seismograph software packages support it? I appreciate a= ny help. Thanks. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Fault Creep Date: Wed, 24 Dec 1997 13:01:54 -0800 (PST) Hi Doug: What can you tell us about the "Palmdale Bulge" that is along the San Andreas? Happy Holidays! Frank Condon mail to:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" >I spent my formative years measuring fault displacement on the San >Andreas system from San Francisco to Palm Springs. We used a Model 2A >Geodimeter with a tungsten lamp (this was before lasers) working between >mountain tops at night in the period from 1959 to circa 1970. > >The USGS continued with a similar program afterwards, but I moved out of >the earthquake business and never got to hear the end of the story (what >was moving where and how much). > >Is there a more recent report I could order detailing fault slip in >California. If anybody cares, I can tell you what was happening then. > >Doug Crice > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: "palmdale bulge" Date: Wed, 24 Dec 1997 17:21:03 -0600 (CST) The Palmdale bulge turned out to be a surveying artifact, as was shown by D. Jackson et al at UCLA (I think) about 1985 or so.It seems that as the leveling survey progressed uphill from the reference tide gauge near LA, the proper refraction correction was not used to correct for the uneven heights of the survey instruments on a slope. With proper corrections, the bulge disappeared into the noise. The USGS promptly ended most research on it in the western Mojave, including a tiltmeter program I had near Lancaster. Most of the fault creep monitoring is being done at Parkfield with a milti-wavelength geodimeter by the USGS. There was also a lot of effort by Roger Bilham at CIRES, but I don't know the status of it. In the creeping section at Hollister and north, there were taught invar wire gauges across the fault with monitor indicators on them that let one actually watch the creep progress; its spooky. Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: coil resistance Date: Wed, 24 Dec 1997 08:54:44 -0800 Sean Thomas My earlier version of the sensor had the feedback resistor and capacitor as you documented but not the integrator. It also had the oscillations! Barry S-T Morrissey wrote: > > Barry, > You probably won't be able to use the triple feedback VBB config > with a 20K coil. If you notice inthe transfer function, that value > (Rf) is a coefficient of the 4-th order term Si**4. When it is large, > the configuration is unstable at the short period end, and the seis > will actually oscillate. But other feedback configs might work. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Fault Creep Date: Wed, 24 Dec 1997 22:54:08 -0800 I'm sure you all have seen the USGS's Parkfield monitoring site at the following URL: http://quake.wr.usgs.gov/QUAKES/crustaldef/park.html Charles _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Mexico City Volcanic Alert Status Date: Thu, 25 Dec 1997 13:55:24 -0800 (PST) Hello All: I haven't heard anything else other than that there was an eruption of a large volcano near Mexico City yesterday. Were there any casualties involved? Thanks, Frank Condon mail to:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Seisguy Subject: Re: Mexico City Volcanic Alert Status Date: Thu, 25 Dec 1997 17:19:47 EST In a message dated 97-12-25 16:55:09 EST, you write: > Hello All: > I haven't heard anything else other than that there was an eruption of a > large volcano near Mexico City yesterday. Were there any casualties involved? > > > Thanks, Here's the article from Reuters........ Mike O'Bleness MEXICO CITY, Dec 24 (Reuters) - Mexico's giant Popocatepetl volcano spewed black smoke four miles (7 km) high and belched a pool of lava late on Wednesday in its strongest explosion since June, volcano experts and media reports said. ``It was a relatively intense but short explosion. The volcano is stable now,'' chief volcano monitor Roberto Quaas told Reuters. ``It is the strongest activity seen since June 30.'' The explosion at about 7:30 p.m. local time (8:30 p.m. EST) (0130 GMT Thursday) sent hot rock and ash into the sky, visible from as far away as Mexico City. Popocatepetl is about 33 miles (50 km) southeast of Mexico's capital. Residents in nearby Tlaxcala and Puebla states said a shower of ash fell briefly after the blast, Radio Red reported. Interior Ministry officials met late on Wednesday and decided against calling a red alert, which would mean the evacuation of villagers at the foot of the volcano, Radio Red said. A June 30 explosion from the 17,719-foot (5,452-meter) volcano forced Mexico City's airport shut and villagers near the peak to evacuate their homes. When Washington state's Mount St. Helens exploded in May 1980, it sent a plume of ash and lava 15 miles high. ^REUTERS@ 22:08 12-24-97 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: Feedback Coil Date: Tue, 23 Dec 1997 12:43:18 -0600 Thanks for the insight Sean. This is one reason I want the get a simulation running. I don't want to be building an oscillator! sean@........... on 12/23/97 11:49:23 AM Please respond to psn-l@............. To: psn-l@............. cc: (bcc: James M Hannon/CedarRapids/Collins/Rockwell) Subject: Re: Feedback Coil >Jim, Barry, et al, >Here is some helpful info re. feedback coils: >For a feedback seismometer the DC resistance of the coil is one >of the terms of the transfer function, and if it is too large w.r.t >other parameters, the function is unstable. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: Feedback Coil Date: Fri, 26 Dec 1997 08:17:38 -0800 Jim -- You wrote: >I don't want to be building an oscillator! Your comment reminded me of an old adage among instrumentation designers: When you design an amplifier, you get an oscillator. When you design an oscillator, you get an amplifier. Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: [Fwd: ] (fwd)(fwd) Date: Fri, 26 Dec 1997 13:04:47 -0700 (MST) ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ ****************************************************************************** ---------- Forwarded message ---------- Date: Mon, 22 Dec 1997 18:17:09 -0700 From: John Moreau To: GEOGRAD@.................. Subject: [Fwd: ] (fwd)(fwd) John Moreau "With an eye made quiet by the power Graduate Research Assistant Of harmony, and the deep power of joy, Department of Geology We see into the life of things." BOX 871404 Arizona State University -Wordsworth Tempe, AZ 85287-1404 (602)965-7029 (602)965-8102 (fax) ---------- Forwarded message ---------- Date: Mon, 22 Dec 1997 09:22:30 -0700 From: Bryan Paynich -FT-~ To: John Moreau , cynthia Subject: [Fwd: ] -- Bryan Shaw Paynich Intel Corporation bpaynich@................ ------- Forwarded Message Return-Path: screel@......................... Received: from pan.ch.intel.com (pan.ch.intel.com [143.182.246.24]) by sedona.intel.com (8.7.6/8.7.3paulmail) with ESMTP id JAA52050 for ; Mon, 22 Dec 1997 09:14:48 -0700 From: screel@......................... 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Message-Id: <86256575.0058F7BC.00@.......................> Date: Mon, 22 Dec 1997 10:11:58 -0500 Subject: Remember the reason for the season:) Mime-Version: 1.0 Content-Type: multipart/mixed; Boundary="0__=OpNtP2AjctYN2hIyxnjvSNW4V1kpMgHaYUthCWoZyHvNscIquS4CGrhT" - --0__=OpNtP2AjctYN2hIyxnjvSNW4V1kpMgHaYUthCWoZyHvNscIquS4CGrhT Content-type: text/plain; charset=US-ASCII - ---------------------- Forwarded by Sher Creel/section33/ladotd/us on 12/22/97 10:17 AM --------------------------- Buffy Brinkley 12/22/97 10:06 AM To: Rittirong Charoenpap/section25/ladotd/us@ladotd, John Chemin/district61/ladotd/us@ladotd, Elvert Chisley/section22/ladotd/us@ladotd, Denis Chon/AMS/ladotd/us@ladotd, Glenn Chustz/section13/ladotd/us@ladotd, Wilma Chustz/section33/ladotd/us@ladotd, Kirt Clement/section22/ladotd/us@ladotd, John Collins/section42/ladotd/us@ladotd, Sarah Collins/section13/ladotd/us@ladotd, Paul Colquette/district05/ladotd/us@ladotd, Derrick Condalary/section13/ladotd/us@ladotd, Joyce Coston/section14/ladotd/us@ladotd, Wynnette Crawford/section42/ladotd/us@ladotd, Sher Creel/section33/ladotd/us@ladotd, Tony Culp/section88/ladotd/us@ladotd, Helene Cumbaa/section19/ladotd/us@ladotd, Gene Cummings/section13/ladotd/us@ladotd, Arthur D'Andrea/section25/ladotd/us@ladotd, Alan Dale/section24/ladotd/us@ladotd, Dale Dauphine/section13/ladotd/us@ladotd, Reggie Dauzat/section08/ladotd/us@ladotd, Lorie Davis/section16/ladotd/us@ladotd, deanl@.................. Rey del Castillo/section24/ladotd/us@ladotd, Frank Denton/section01/ladotd/us@ladotd, Kathy Devall/section13/ladotd/us@ladotd, Roddy Dillon/section53/ladotd/us@ladotd, District 02, District 03, District 04, District 05, District 07, District 08, District 58, District 61, District 62, LA DOTD1/PERBAdmn/ladotd/us@ladotd, LA DOTD2/PERBAdmn/ladotd/us@ladotd, LA DOTD3/PERBAdmn/ladotd/us@ladotd, LA DOTD4/PERBAdmn/ladotd/us@ladotd, Joseph Douglas/section25/ladotd/us, Bill Drake/section42/ladotd/us@ladotd, Janice Drake/section16/ladotd/us@ladotd, Ken Duay/district02/ladotd/us@ladotd, Tony Ducote/section25/ladotd/us@ladotd, Morgan Dugas/section25/ladotd/us@ladotd, Angele Dumestre/section13/ladotd/us@ladotd, Jason Dunlap/section13/ladotd/us@ladotd, Farilyn Dupuy/section16/ladotd/us@ladotd, Roy Dupuy/section42/ladotd/us@ladotd, Larry Durant/section47/ladotd/us@ladotd, Cheryl Duvieilh/section47/ladotd/us@ladotd, Karen Dykes/section13/ladotd/us@ladotd, Marcia Easley/section01/ladotd/us@ladotd, Bruce Easterly/district04/ladotd/us@ladotd, Udeme Edoho/section13/ladotd/us@ladotd, Johnny Edwards/section42/ladotd/us@ladotd, ellingtn@.................. John Evanco/district02/ladotd/us@ladotd, Dee Everett/section16/ladotd/us@ladotd, ewingr@.................. Sal Faldetta/section15/ladotd/us@ladotd, acs@....... cc: Subject: Remember the reason for the season:) - ---------------------- Forwarded by Buffy Brinkley/section66/ladotd/us on 12/22/97 10:07 AM --------------------------- Nicole Smith 12/22/97 09:35 AM To: David Brewer/section67/ladotd/us@ladotd, Ed Preau/section64/ladotd/us@ladotd, Juanita Saltzman/section64/ladotd/us@ladotd, Kimberlee Holland/section64/ladotd/us@ladotd, Dot McConnell/section65/ladotd/us@ladotd, vandeman@............... jgs@.............. Buffy Brinkley/section66/ladotd/us@ladotd, acs@....... cc: Subject: Remember the reason for the season:) - ---------------------- Forwarded by Nicole Smith/section65/ladotd/us on 12/22/97 09:33 AM --------------------------- (Embedded image moved madison@........... to file: 12/21/97 12:59 AM PIC29537.PCX) To: tgnnet@....... cc: hockey@........ rawaller@.................. theroux@............ bkts@.......... hal9000@.......................... rondaw@.............. hvymtl@........... jskyzer@......... devnull@............... JFerr1968@........ jenger@............. Rottymax@........ ohhsaint@............ josr@............ sens@......... mpci@........... dkenn19@........ sidbec@.............. KasentA@........ drye@............ u1005311@............ mickster@.............. ples@........... swilliam@........ mastern@............... thequeb@........... nitrosteve@........ dmccombs@........ lshotts@............ andy@.................... sthrn.cmfrt@........... kimp@......... madison@............ bhi@................. dvnsu@........ frank@......... chuck.powers@........ nicolson@........ jgs@.............. onevol@........ jacks@............. heart-j@...................... brclaas@.............. stonecld@......... Raggwingg@........ jugrnot@................ twrlyg@........ hoc1sg@.............. katlovr@........ undercofler@............. kajunqween@........ mab@............. washbass@................ BOLDER@............ easy@............ cab@.............. ix-ball@......... digs@............ olscarol@.......... 623435@......... mm@.......... daddyno@.............. slvrtree@.............. olscarol@......... ppottier@........ Eymhere@........ stevedm@............ rachelle@............... Gailwinds5@........ est@............ navsk8@........ me_u_642@............ bsnodgrass@............. bigjim@.......... dethnite@........ gopone.com@.......... werner@............ Eymhere@........ Nicole Smith/section65/ladotd/us, fsbill@........ anniew@......... wooie@.............. rhuenefeld@................. aeropilot@............ sk@............ mms046@............ ssher@.......... jrichview@............. andee@.............. csis@................ noles1@............. whattodo@.............. chaz@............ seald@.............. nengle@............. hwpere@.............. patriot@.......... bhaynes@.............. NAMartin1@........ colibri@......... rawaller@.................. diamond@............ tima@......... brownlegs@............ david.cote@......... numa@........ acs@....... Subject: Remember the reason for the season:) This one is important. No comedy here. It's about a seven year old girl with cancer. Read it and pass it on to as many people that you can. Occasionally we get to use this medium for some actual good, rather than trading barbs across the waves. And once in a while things like this bring us back to reality, allowing us to count ourselves lucky in life. Let's put our network to work here! It will only take you a second to send this message ************************* Jessica Mydek is seven years old and is suffering from an acute and very rare case of cerebral carcinoma. This condition causes severe malignant brain tumors and is a terminal illness. the doctors have given her six months to live. As part of her dying wish, she wanted to send a letter to inform people of this condition and to send people the message to live life to the fullest and joy every moment, a chance that she will never have. Furthermore, the American Cancer Society and several corporate sponsors have agreed to donate three cents toward continuing cancer research for every new person that gets forwarded this message. Please give Jessica and all cancer victims a chance. Add acs@....... to the list of people that you send this to so that the American cancer society will be able to calculate how many people have gotten this. If there are any QUESTIONS, SEND THEM TO THE AMERICAN CANCER SOCIETY AT acs@....... Three cents for every person that receives this letter turns out to be a lot of money considering how many people will get this letter and how many people they, in turn, pass it on to. Please go ahead and forward it to whoever you know - it really doesn't take much to help out. ******************************** Jean Ann Linney, Ph. D. Professor and Department Chair Department of Psychology University of South Carolina Columbia, SC 29208 Phone: 803-777-4301 Fax: 803-777-9558 Thanks and have a Great Day! Karen L. Dalton CTSG kldalton@........... 513-397-9954 voice - --0__=OpNtP2AjctYN2hIyxnjvSNW4V1kpMgHaYUthCWoZyHvNscIquS4CGrhT Content-type: application/octet-stream; name="PIC29537.PCX" Content-transfer-encoding: base64 CgUBCAAAAABoACwAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAABaQABAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAD1E9sTzRPHE8MTwhP1E9sTzRPHE8MTwhP1E9sTzRPHE8MTwhP1E9sTzRPH E8MTwhP1E9sTzRPHE8MTwhP1E9sTzRPHE8MTwhP1E9sTzRPHE8MTwhP1E9sTzRPHE8MTwhP1E9sT zRPHE8MTwhPwEwzIBgzYE8wTxhPDE8IT7hPOBtcTzBPGE8MTE+wTwgbCBwbCEgbCEgbCEsUG1hPL E8YTwxMT6hMMwgYHwgLCAwISwgfEEsMCwwbVE8sTxRPDExPpE8MGAwcCBwMCwhLDB8ISwgISwgLD BtUTyhPFE8MTE+gTwgIHA8ICEw4DDgLDE8USwwLCEMIG1BPKE8UTwxMT5xMCAwcDAg4TDgITwgIS D8ISD8ISBRICEcICwwbUE8oTxRPCExPmEwYCBwMCDgIOwgLDExITEhPCEg8GxgLDBtMMDAfJE8QT whMT5hMGwwITBgMCDhLFEw8SE8ISBgIDwhIDEsMGB9MDxwwHxRPDExPlEwYHAhESAg8CwhMPwhMP xBMPxRIQwgIDAgMCBtMDxwPEDAfDE8IT4RMHwwzCBgLCEhMCDxLIE8MSD8MSwwIQAwIDBgfSDMkD wgPCDAfCExPbEwfGDMIDDAIHERITEhMSwxMPwxMPwxPDEgIDAgMCwwMCBgzREwfHDMYDDMITE9YT B8UMyAMGB8ICBhLDAsYTEhMSExIPwhIHAgcCAwUQAgYRBgfSE8UTB8QMwgMMwhMT0hMHxAzLA8IM BsISDxESExITAw4DxBMSExITwxICBwPCAsMDDMIGB9ITyRMHwwzCExPPEwfDDMkDxQwHwhMGBxIT AhECEwMOAg7DExITDxMPwxIDAgMCBwMCDAYRBgfSE8kTwhPCDMITE8wTB8MMxwPEDMIHxxMGxBLD Ag4DDgIGwg/IEgIDwgIDAgwCEMIGB9ITyRMHDAcMwhMTyhMHwgzGA8MMwgfMEwYHwhLCEAIOAg4C DhDDAhIPxhIFAgXDAgUCEQYH0hPHEwfCDAcPDMITE8gTB8IMxQPDDAfQEwbDEhDEAhAOEA4QwgLG EgcSBhIGBcMCBcIGB9ATB8UMEwfCDA8HDwwHwhMTxhMHwgzEA8MMB9MTBgfCEhADEMICDhAOEMIC EQIDxxIGBwbCAgUCEQYHyxMHxAwHwhMHEwzCEwcPBw8MB8MTE8UTBwzEA8IMB9YTBsQSEAMCA8UC EQIDAgPDEgcSBgfCBgUQAhDCBgfGEwfEDAfGE8INEwzCEw8HwgwHwxPCE8QTBwzDA8IMB9gTBgfE EhACEMYCEQIDAsQSBhLDBsICEALCBgfCEwfDDAfKEwfCDRMHwhPCDAfEE8ITE8MTBwzCA8IMB9oT DBIHwxLDDBEDxQIDAgPDEgYSBgfCBgIQAhAGDAfCEwzDE8MHyRMHwhPCBxMHxRPDExPDEwzCAwwH 3RMGxxICEQPDAgMCA8MSBhIGBwYMBhACEAIGDMMTDBPCB8YTwwfHEwfGE8MTwhPDEwwDDAfeEwYH xxICEQPDAgMCwhIGEgYHBgwGEAIQAsIGB8MTDMYTwwfKEwzGE8MTwhPDE8IMB98TDBLCB8USAgMR xAISB8ISBgcGDAYQBhAGEAYMB8MMB8kTwwfHEwzGE8MTwhPDEwwPwgzfEwYSB8ISB8ISAhECAwID EgcSBwYHBgwGEAYQxgzDD8IHxRPDB8kTBwzGE8MTwhPDEwzDD8QM3BPCBhIGwxIGAhECAwIHBgcG yAzJDxMHzRMHwwwHxxPDE8ITwxMHDMYPxwwH1BMGEgYSBhLLDM4PwwwTDMcTwgfEDAfJE8QTwhMT xBMHwgzLD9sM0w/GDAfDEwzDEwfEDAfLE8YTwxMTxhMHxAztD8gMBgfIE8QMB84TxxPDE8ITyhMH xwzbD8sMEAUMBcIMwgYH1RPKE8UTwxMT0RMH2wwGEAYQBhACBQwFDAUMBgwHBgfWE8sTxRPDExPu EwYMBhAGEAIGDAYMwwYH1xPLE8YTwxMT8BPKBgfYE8wTxhPDExP1E9sTzRPHE8MTwhP1E9sTzRPH E8MTwhMMAAAAgAAAAIAAgIAAAACAgACAAICAwMDAwNzApsrw//vwoKCkgICA/wAAAP8A//8AAAD/ /wD/AP//////AAAAgAAAAIAAgIAAAACAgACAAICAwMDAwNzApsrw//vwoKCkgICA/wAAAP8A//8A AAD//wD/AP//////AAAAgAAAAIAAgIAAAACAgACAAICAwMDAwNzApsrw//vwoKCkgICA/wAAAP8A //8AAAD//wD/AP//////AAAAgAAAAIAAgIAAAACAgACAAICAwMDAwNzApsrw//vwoKCkgICA/wAA AP8A//8AAAD//wD/AP//////AAAAgAAAAIAAgIAAAACAgACAAICAwMDAwNzApsrw//vwoKCkgICA /wAAAP8A//8AAAD//wD/AP//////AAAAgAAAAIAAgIAAAACAgACAAICAwMDAwNzApsrw//vwoKCk gICA/wAAAP8A//8AAAD//wD/AP//////AAAAgAAAAIAAgIAAAACAgACAAICAwMDAwNzApsrw//vw oKCkgICA/wAAAP8A//8AAAD//wD/AP//////AAAAgAAAAIAAgIAAAACAgACAAICAwMDAwNzApsrw //vwoKCkgICA/wAAAP8A//8AAAD//wD/AP//////AAAAgAAAAIAAgIAAAACAgACAAICAwMDAwNzA psrw//vwoKCkgICA/wAAAP8A//8AAAD//wD/AP//////AAAAgAAAAIAAgIAAAACAgACAAICAwMDA wNzApsrw//vwoKCkgICA/wAAAP8A//8AAAD//wD/AP//////AAAAgAAAAIAAgIAAAACAgACAAICA wMDAwNzApsrw//vwoKCkgICA/wAAAP8A//8AAAD//wD/AP//////AAAAgAAAAIAAgIAAAACAgACA AICAwMDAwNzApsrw//vwoKCkgICA/wAAAP8A//8AAAD//wD/AP//////AAAAgAAAAIAAgIAAAACA gACA//vwoKCkgICA/wAAAP8A//8AAAD//wD/AP////// - --0__=OpNtP2AjctYN2hIyxnjvSNW4V1kpMgHaYUthCWoZyHvNscIquS4CGrhT-- ------- End of Forwarded Message From: Doug Crice Subject: Re: [Fwd: ] (fwd)(fwd) Date: Fri, 26 Dec 1997 15:32:07 -0800 The Jessica Mydeck story is one of the more popular "urban legends" which are spread on the Internet. It doesn't appear to be true, but look at the number of folks who were exposed in this round. A number of internet sites address these stories, for example http://urbanlegends.miningco.com/ These's even a government site that tracks these, but I lost the URL. Doug Crice _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: Feedback Coil Date: Fri, 26 Dec 1997 21:25:06 -0600 (CST) Jim, Barry, Karl, and co: It is helpful to understand a key point about the VBB feedback. When the base or frame experiences an acceleration of the ground, the inertia of the mass causes a small displacement of the boom, and the displacement transducer produces a voltage proportional to the small displacement. This is coupled to the feedback coil through the feedback components Rp, C, and RI, producing three characteristic CURRENTS in the feedback coil. These currents produce forces that attempt to prevent the mass from moving in response to the input acceleration. With the feedback functioning, the displacement transducer output then becomes the VBB output voltage that is flat to velocity. Because the feedback is in the form of currents through passive components, the dynamic range is not limited by any active electronics, and easily exceeds 120db. I have used the MATHCAD model to iterate on variations of all the feedback components; it readily shows the instabilities as any of the parameters are varied over what seemed to me to be reasonable values. Of course the trade-offs are endless, but only a narrow range of values will indicate a stable and flat response. This is why my early efforts at "just trying it" were notably unsuccessful, producing lots of oscillators. If you don't have access to a MATHCAD model (or equiv.), send me the known parameters of your seismometer, and I will try to model it. A quick pass with Karl C.s parameters shows that a response from 40 seconds to 10 hz is possible with some changes, notably reducing mass from 2.7kg to 0.3 kg. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: Feedback Coil Date: Fri, 26 Dec 1997 21:27:44 -0600 (CST) And I often had the problem that neither the amplifier nor the oscillator would work unless the Simpson multimeter was attached to the circuit somewhere. I could never find the electrical equilavent of the multimeter. Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Brian Chesire Subject: Re: Feedback Coil Date: Fri, 26 Dec 1997 20:43:03 -0700 My equivalent to the ubiquitous Simpson is the 2N2222, If there is not at least one doing something, somewhere in the circuit it's guaranteed not to work. Brian WA5PPO Tucson, AZ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Seisguy Subject: Fwd: Montserrat Volcano Spews Ashes Date: Fri, 26 Dec 1997 23:05:45 EST Here's another volcano article for those of you interested..... Mike O'Bleness Northridge, CA 

Montserrat Volcano Spews Ashes


.c The Associated
Press


 ST. JOHNS, Montserrat (AP) - With a continuous roar, the Soufriere Hills
volcano on this Caribbean island spewed ashes high into the sky early Friday,
setting off a show of lightning.

Two days of rumbling preceded the volcano's ``pyroclastic flow'' - an eruption
of 1,000-degree gas, ash and rocks. The debris settled in a long-abandoned
area southwest of the volcano.

The volcano spewed ash 36,000 feet into the sky.

Most of the residents of the British colony have left the island since the
volcano began erupting in July 1995. Predicting the eruptions is difficult,
and scientists could not say if Friday's blast was leading up to a bigger one.

``Every few weeks we seem to get some elevated activity,'' said Stephen
Sparks, chief scientist at the Montserrat Volcano Observatory. ``This seems to
be the latest one.''

``The volcano just told everybody it's still there,'' Sparks said.

Ash from the eruption did not affect the northern part of the 39-square-mile
island where the few remaining residents live.

One effect of the eruption may actually be pleasant for residents and
vacationers in the northeastern Caribbean.

The U.S. National Weather Service in Puerto Rico said upper-level winds would
likely keep the ash from falling to earth, but the hazy skies could result in
some spectacular sunsets.

AP-NY-12-26-97 1328EST


 Copyright 1997 The Associated
Press.  The information  contained in the AP news report may not be published,
broadcast, rewritten or otherwise distributed without  prior written authority
of The Associated Press. 


 

To edit your profile, go to keyword NewsProfiles.
For all of today's news, go to keyword News.
From: barry lotz Subject: Re: Feedback Coil Date: Fri, 26 Dec 1997 10:26:13 -0800 Sean Thomas Is the integrator made of passive components also? I was going to make it with an op amp until I read your latest posting. With passive components it's a low pass filter. BTW, I just cut out the cone. The clearances are pretty tight. I will mount the magnet in such a way as to be able to allow for some adjustment, like between 3 screws. Also, I think I'm going to try it in a horizontal sensor. Barry S-T Morrissey wrote: > > Jim, Barry, Karl, and co: With the feedback functioning, the displacement transducer output > then becomes the VBB output voltage that is flat to velocity. > Because the feedback is in the form of currents through passive > components, the dynamic range is not limited by any active electronics, > and easily exceeds 120db. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: integrator Date: Sat, 27 Dec 1997 11:20:04 -0600 (CST) Barry, The integrator is made with active components, but has unity gain, so its' clip level is the same as the VRDT or LVDT amplifier. I use a 3 op-amp "instrumentation amp" configuration to minimize the effect of leakage of the integrator capacitor. A very high quality single amp would probably also do, like the OP177 or the MAX140 series. As you note, a simple low pass single pole filter is also an integrator, but an amplifier is needed to drive the relatively low impedance (compared to the integrator resistor of several megohms) of the integral feedback resistor. For mounting the speaker magnet, I use the hole through the center of the magnet pole, which was 1/2" on the first one, but only 7/16" on the second one. I use a 3/8" stainless steel threaded rod, washers, and a 5/8" hole in the base to allow for fine positioning of the magnet, which lays flat for the vertical. For the horizontal, mounting it to a large aluminum angle first allows a similar arrangement for adjustment. I do not make any effort to make a permanent mount for the magnet just because of the need for fine positioning, and I just assume that it will be removed if the instrument is to be transported. Before you mount the speaker coil, be sure to add a 5 to 20 turn winding of fine wire (eg#36) for calibration. I wind it just above the main coil, at the base of the remaining cone. It is not in the main gap of the magnet pole, but the fringe field is quite adequate a few mm above the pole face. The step calibration is a relatively easy way to verify the instrument performance. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Notice the 3 SAF M3's... Date: Sat, 27 Dec 1997 11:20:40 -0800 Golly, did you notice the trio of M3's along the locked southern portion of the San Andreas fault at the Salton Sea? They occurred north of the Obsidian Buttes where activity is relatively common. These events are the first in this magnitude range here in some time. The Coachilla Valley segment last ruptured in 1690. -- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration / Seismo-Watch Voice: 702-852-0992 / Fax: 702-852-3226 mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: from Italy Date: Sat, 27 Dec 1997 17:18:58 -0700 Giovanni- Merry Xmas (a little late) and Happy New Year to you, too! I looked at your record and its FFT spectrum with Winquake. I see your sample rate is 10 sps, and therefore, the Nyquist frequency is 5 Hz. You probably have an anti-aliasing filter at about 2 Hz because the spectrum is peaked at about 1.7 Hz, though this could be a site effect, i.e., a resonance of the glacial moraine layer under your instrument. What is the corner frequency of your anti-aliasing (low-pass) filter? In terms of the source spectrum, the corner frequency of a magnitude 3.5-4.0 earthquake should be about 10 Hz, and this implies that you should record this event at about 50 sps. Of course, there will be alot of attenuation of the high frequencies since the event is 300 km away. I am not able to pick the S-wave arrival, or rather, distinguish it the S-wave from the later arriving Lg and surface waves. The monochromatic nature and "beating" of the seismogram suggests that you should increase your sample rate if you want to record these local and regional events. Good luck! I look forward to your developments. -Edward Giovanni Rotta wrote: > > Hi, Ed !! > Merry Christmast and Happy New Year ! > I send you the file of the recent event in northern Italy for your > evaluation. > Have a good time ! > Giovanni > > Giovanni Rotta > rottag@.......... > Via F. Pizzigoni, 10 > 33010 Resia (Udine) Italy > Lat. 46.22N Long. 13.18E > > --------------------------------------------------------------- > > Name: 971224b.gr1 > Type: unspecified type > Part 1.2 (application/octet-stream) > Encoding: base64 > Description: 971224b (GR1 File) -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: Re: LEAF-SPRING Date: Sat, 27 Dec 1997 20:25:20 EST SEAN-THOMAS I purchased a beautiful dry wall taping knife from Home Depot with a 12 X 3 inch flexible blade. With its stained handle its almost to beautiful to remove the blade and destroy - Oh well. My question is what should be the orientation of the spring when mounted under the boom. Should the open end of the curved semicirclar spring face the rear or towards the front where the coil is placed - or does it matter? My guess is that yours has the open end of the semicicle spring facing towards the rear ending about three inches from the upright support. Thanks Jim Allen Cerritos, CA. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: Re: EMON Date: Sat, 27 Dec 1997 22:34:17 EST TED BLANK et.all I just received an A/D board CIO-DAS08/JR (12 bits) from a company called ComputerBoards. I understood that this unit should work with programs such as EMON. However, when I downloaded EMON this board is not listed in its menu of boards that it is configured to run. Is there a way to have EMON utilize this board? My Board also came with a program called LabTech Notebook where you program the A/D functions with Icons (Dont need to know a lick of programming language). Since I just received it I placed two icons on the programs desk top and hit the start button and it automatically begin capturing a signal from my radiotelescope. Has anyone utilized this program before for seismometry applications? The potential seems to be great. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: fmurray@......... (frank murray) Subject: Re: Notice the 3 SAF M3's... Date: Sun, 28 Dec 1997 05:03:54 GMT On Sat, 27 Dec 97 19:20:40 +0000, you wrote: >Golly, did you notice the trio of M3's along the locked southern portion= =20 >of the San Andreas fault at the Salton Sea? They occurred north of the=20 >Obsidian Buttes where activity is relatively common. These events are=20 >the first in this magnitude range here in some time. The Coachilla=20 >Valley segment last ruptured in 1690. do you know of a map available on line that divides the san andreas by the times of its ruptures??... frank fmurray@......... for my electronic college proposal see: http://home.att.net/~fjtmurray/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Is Mammoth Mountain Picking up Steam? Date: Sat, 27 Dec 1997 21:45:24 -0800 (PST) Hello All: After visiting the USGS Web-site for the latest information about earthquakes in the caldera, I noticed there were two M3.0 within a couple of hours of each other today. Does this mean that the caldera is coming back to life again? Frank Condon mail to:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: LEAF-SPRING Date: Sun, 28 Dec 1997 00:13:12 -0600 (CST) Jim, I buy the cheap one with the plastic handle in paint department at Builders Square for ~$8. THe leaf spring is installed with the orientation that you surmised. I have not completed the documentation on the mounting of the spring. If you send a SASE I will send you the available drawings. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: Re: LEAF-SPRING Date: Sun, 28 Dec 1997 01:56:24 EST SEAN-THOMAS Thanks. I will send the stamped envelope for the drawings. Jim Allen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Re: EMON Date: Sun, 28 Dec 1997 08:07:25 >I just received an A/D board CIO-DAS08/JR (12 bits) from a company called >ComputerBoards. I understood that this unit should work with programs such as >EMON. I would be interested in where you got the board and how much you payed. I am into ra also. Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: Re: EMON Date: Sun, 28 Dec 1997 11:55:37 EST TO: NORMAN DAVIS I purchased the A/D board from a company called ComputerBoards, Inc., located in Mansfield, MA. There pho. # (508) 261-1123 FAX# (508) 261-1094, WEB SITE: www.computerboards.com As indicated, I purchased the CIO-DAS08/JR (12-bit resolution, +/- 5V input,20 KHz Max sample rate, 8 input channels) which cost $99.00 purchased alone. However, I bought a package deal of the A/D board and Labtech Notebook software for $199.00. I also sprung for the connecting kit, DFCON-37, which included a terminal board and 37 wire cable for an additional $75.00 since I did not want to cobble my own hook-up which could have been done for much less money. The Board and especially the software is fantastic. I am in the process of learning how to program it which appears easy since you only use icons and not programing language. As for Bill Kennedy when you contact the company - he is very helpful. By the way, the company has an on- line catalog on their web site. Best wishes Jim Allen Cerritos, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: VBB Conversion Date: Sun, 28 Dec 1997 12:02:29 -0600 (CST) Bob, I am quite familiar with the "baby" benioff; I still have several in service (w. telemetry, or course), and even have the prototype of the "Big" Benioff for the WWNSS sitting on the pier under the old gym at SLM. They also make good demo seises. However, even with the 8 coil configuration, I think that the hugh inductance may be a problem. But with the coils in a low Z parallel configuration (eg to drive an 80 ohm galvo, as in the manual: do you have it?) it might work. I have converted a number of old seised to VBB, but have not done a model for the 4681A, but I will. I looked at the S-13, but it is hard to find it in a low resistance coil. I have a Columbia-Sprengnether LP-Z (the WWNSS version) running at 600 seconds though. I don't have the Validyne info here at home. The electronics is the unpotted module that they use in their diaphram gauges. I have completed most of the write-up on making the displacement transducer. I'm trying to get all the info and photos on my web site, but I have too much to do other than getting into the time trap of a web site. But I can sent you the next draft of the paper if you send a 9x11 SASE. BTW, I am an instrumentation packrat of sorts, beginning in 1969. I have an hugh old underground munitions bunker for a test vault ... and an Attic. So I have quite a collection of Geotech originals, including PTAs (LP and SP) from the station ADK in the Aleutians, which I operated (from SLU) from 1976 to 1993 with modern telemetry and a 14 station regional network for CIRES. When that funding ended, we pulled it all out (including the 400 lb big benioffs), and left behind an IRIS station with STS-1s. Maybe you remember "Doc" Hall at Geotech, who was my main contact. He sent me all the remaining parts for your 14-track, 14 day recorders, since I was still running two of them until about 1984. So I still have them, along with other Geotech "goodies", like three develocorders. I use an old "portacorder" here as a monitor for the 90 second home made leaf spring seis; I have converted it to write on FAX paper with a heated stylus. I'll let you know if the transfer function of a "baby benioff VBB" can indicate a workable configuration; maybe you can do it yourself. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: VBB conversion specific to Sprengnether Date: Sun, 28 Dec 1997 15:49:10 -0800 Hi Sean-Thomas Your reference today to the the Columbia-Sprengnether LP-Z, the WWNSS version, and being successful in VBB conversion is of very, very strong interest too me, as I have the model and 2 same time period horizontals. I have only a poor electronics experience background, but only perseverance. Yes....you guessed it;....I'am interested to know, if perhaps you may have schematics available on that conversion? Any other stuff like drawings, pictures, would be also received with much enthusiasm if possible, or available. Perhaps....(?)....it is much like the present VBB circuitry details you have been generiously supplying to PSN email recipients?? P.s.....yes, they have 500 ohm coils. Thank you, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: George Bush Subject: Re: EMON Date: Sun, 28 Dec 1997 16:36:15 -0800 At 08:07 AM 12/28/97, you wrote: >>I just received an A/D board CIO-DAS08/JR (12 bits) from a company called >>ComputerBoards. I understood that this unit should work with programs >such as >>EMON. > > I would be interested in where you got the board and how much you payed. > I just bought a CIO-DAS08/Jr/16. It is similar to the above board but has 16 bits resolution and costs less than $200 from ComputerBoards. If you need more resolution then you might want to consider this board. You get a lot of bits for the buck. Ted Blank has graciously offered to add a driver to EMON so it is another tool in our seismic toolbelt. I live almost on the San Andreas fault and wanted more dynamic range for my location than the 12-bit board offered. George Bush- Sea Ranch CA, USA George _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: S5000 VBB Date: Mon, 29 Dec 1997 00:33:36 -0600 (CST) Meredith, Re: WWNSS LP seis conversion to VBB: Send me a SASE and I will send you the info I have, including a partial schematic. I am using the VRDT transducer with the Validyne electronics. The 500 ohm coils work on the beast only because they have a hugh generator constant (like 90 N/A), and the mass is large (11kg). I leave the mechanical period at 15 seconds, but with the VBB feedback I operate it at an effective period of 600 seconds. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: microbarographs Date: Mon, 29 Dec 1997 00:45:12 -0600 (CST) Ben, I will send you the info on the one I assemble with the Taylor compensated mechanism (pricy, like $200), the Schaevitx 005mhr LVDT, and the Validyne electronics. It has an output of 100mv/millibar, and with the dial mechanism disengaged, microbar sensitivity. It is sensitive enough to calibrate it simply by moving it vertically a few centimeters in the atmospheric pressure gradient. I have presented two papers on using the data from such a unit to compensate/remove the barometric noise from very broadband data, like the STS-1s at IRIS stations. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Marnie Gannon Subject: Princeton Earth Physics Project Date: Mon, 29 Dec 1997 10:17:36 -0700 Just for your info.looking around the web and found this ongoing project to provide seismographs and technical support to high schools throughout the US. Currently only a few stations are online, and there are none in California. I seem to recall a few PSN posts talking about a project just like this...It's worth taking a look at the whole site.. Marnie=20 > [Image] >=20 > Welcome to the > Princeton Earth Physics Project > HomePage. >=20 > The Princeton Earth Physics Project is an educational project of > Princeton University in collaboration with other members of IRIS, with > financial support from the National Science Foundation. PEPP is > building a network of seismic recording stations in high schools > across the US. Students use the PEPP network to study earthquakes and > build research skills using real seismic data. PEPP's WWW server > provides access to seismograms recorded by the PEPP Seismograph > Network and other networks, access to a global seismicity database > through QEDs and earthquake catalogs, and many other useful resources > associated with PEPP or available on the Internet. >=20 > NOTE: We have reorganised the curriculum projects so old bookmarks may > not work!! >=20 > [Image] PEPP Curriculum Projects >=20 > [Image] Feedback or questions to PEPP >=20 > [Image] PEPP Software >=20 > [Image] PEPP data >=20 > [Image] PEPP Seismograph Network -- station locations, maps, and > network status >=20 > [Image] Join the PEPP Mailing List >=20 > [Image] Online versions of the PEPP Newsletters >=20 > [Image] Other Information >=20 > ---------------------------------------------------------------------- > [Image] [Image] [Image] >=20 > ---------------------------------------------------------------------- > [Image] >=20 > PEPP has been selected as an Eisenhower National Clearinghouse Digital > Dozen site >=20 > ---------------------------------------------------------------------- > Send comments and suggestions about the PEPP Web Pages by email to Dr. > Bob Clouser bclouser@................. >=20 > Document updated September 30, 1997 11:30AM EST. > Copyright:=A9 PEPP, 1996, 1997. All rights reserved. >=20 > These pages are best viewed with Netscape Navigator browser. http://lasker.princeton.edu/pepp.shtml _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: bob@................. (Bob Hammond (USGS-AVO Geophysicist)) Subject: Re: EMON and ComputerBoards CIO-DAS08Jr. Date: Mon, 29 Dec 1997 09:28:33 -0900 All of the schools participating in the APSN use the ComputerBoards CIO-DAS08Jr A/D board. EMON is used as well. I asked Ted Blank to modify EMON to use this board which he did some two years ago. I can provide copies of EMON for use with the CIO-DAS08Jr A/D if it's ok with Ted. Ted? regards, Bob Hammond Alaska Public Seismic Network Fairbanks _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: bob@................. (Bob Hammond (USGS-AVO Geophysicist)) Subject: Re: EMON Date: Mon, 29 Dec 1997 09:45:20 -0900 To get the version of EMON which supports the ComputerBoards CIO-DAS08JR A/D board: ftp to: eq.giseis.alaska.edu login as: anonymous give password as: your email address cd to /home/ftp/pub/bob/emon/ get the files there: emon.exe, emon.opt, emon.doc, quakevu.ini, quakevu.exe Let me know if you have problems getting the files. EMON.opt at this ftp site is the one I used at station GSV and is used by the schools I work with. regards, Bob Hammond APSN Fairbanks _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ken Navarre Subject: Re: LEAF-SPRING Date: Mon, 29 Dec 1997 12:33:50 -0800 (PST) On Sun, 28 Dec 1997, S-T Morrissey wrote: > I buy the cheap one with the plastic handle in paint department at > Builders Square for ~$8. THe leaf spring is installed with the orientation > that you surmised. I have not completed the documentation on the > mounting of the spring. Word of caution regarding the spring... It'd be a good idea to wear safety glasses while experimenting with the mounting! IT has a tendancy to shoot across the room until you get it "nailed" down. I've attached mine with a small steel wire thru holes drilled thru the rod attached to the ends of the leaf spring. Also, instead of using the brass rod and having to deal with cutting a slot for the spring to fit in I found that steel "roll pins" are just perfect. The leaf spring fits snuggly in the slot of the roll pin and is easily epoxied. Until I get the electronics up and running I've incorporated the "lehman" principal into the design and have now got a pretty spiffy vertical "sensor with a period of about 8 seconds. Too bad I didn't have it up and running for this morning's 4.6 at Mammoth... Regardss Ken _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: Re: EMON Date: Mon, 29 Dec 1997 16:33:24 EST BOB HAMMON (USGS-AVO Geophysicist) Thanks very much Bob. Happy New Years. P.S. If you want to try the program I am using let me know. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: Re: LEAF-SPRING Date: Mon, 29 Dec 1997 17:05:04 EST KEN Thanks for the advice regarding safety in installing the leaf-spring. Your project sounds interesting. would like to hear more about it on the list. I am also looking into modifying some of the provisions of the leaf-spring seismometer developed by Sean-Thomas. By the way that's one guy that I would like to meet someday - he is great. Anyway, I am considering using four small neodymium rare earth magnets, with one attached to the top of the boom and another to the bottom each repelled by a simular magnet placed about a 1/4 of an inch from and facing the above two. I theorize that by sandwiching them in this fashion they sould damp the booms up and down motion and, at least crudely serve as a replacement for the feed-back coil in Sean-Thomas's seismometer. In the event that this does not work, I did purchase a large 12 inch speaker. Happy New years Jim Allen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: LEAF-SPRING Date: Mon, 29 Dec 1997 16:52:20 -0600 (CST) Ken and Jim, The word to the wise about out-of-control leaf springs IS good advice. One of mine got loose and flung a good collection of small stainless hardware into the next room, causing my dogs to panic and hide in the bedroom. Ken's idea for a suspension of the spring sounds like the "taught-band" arrangement I tried with fine stainless fishing leader attached thru small holes across each end of the spring material and tensioned by a wide AL channel. I was not confident in its' stability, and became concerned about the mechanical noise of the arrangement. Of course, there are many trade-offs to be evaluated. The important point of my design is that the ends of the spring must be able to flex; clamping them introduces the rigity of the spring itself; we just want the lift. BTW, the spring material can be drilled with the "cobalt" style drill bits, using an oil coolant (3-1, 20w, etc.), and pushing the drill as fast as you can; if you drill slowly, its the re-enactment of fire-by-friction, and ruins the bit at once. Regarding damping with magnets, it was used on all the early seismometers that has optical levers. It uses the principle of eddy currents, where a thick copper vane moves in a very strong magnetic field. The movement causes currents in the copper, whose induced field counters the motion. I would consider using rare-earth magnets with an old real copper penny. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: Re: LEAF-SPRING Date: Mon, 29 Dec 1997 18:24:49 EST SEAN-THOMAS Thanks for the advice and idea about using copper pennies. I will try that. Your ideas and advice have been invaluable. I had the UC Berkeley Earthquake Engineering Research Center Library send me a photo-copy of the article by E. Wielandth and G. Streckeisen from the Bulletin of the Seismological Society of America Subject: The Leaf-Spring Seismometer - Design and Performance. Its OK reading although I don't understand all the technical stuff in it. Actually, I have learned more from your description of your project. I hope that you publish it not only on the web but in one of the popular magazines. Can you imagine the ideas it would give to high school and college students interested in this field. Jim Allen Cerritos, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: SFBA PSN records for Mike Antolik Date: Mon, 29 Dec 1997 16:57:18 -0700 PSN members in the San Francisco Bay Area- Dr. Mike Antolik of the Seismograph Station at UC Berkeley is developing 3-dimensional, finite-difference models of seismic wave propagation and site response in the San Francisco Bay Area. He would like to have some low-frequency records (< 0.5 Hz) of local earthquakes recorded by stations in the Santa Clara Valley, on the flat land adjacent to the Bay, and on the hills immediately adjacent to the Bay. The records should be unclipped and high signal/noise and provided with as much information about instrument response as possible. I know that this is asking alot, but it will be interesting to see what is available. Please provide me with a list of these records, and please upload the records themselves to the Redwood City PSN server (i.e., Larry) if they have not already been uploaded. Mike has already run some wave propagation models similar to those done by Art Frankel, USGS, that I presented at the PSN meeting at USGS Menlo Park on 20 Dec, but I don't know if any of these models are available on the web yet, but I will find out. I look forward to seeing what the Bay Area PSN has recorded in the neighborhood during the the 1990's. -Edward -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: VBB Feedback Date: Tue, 30 Dec 1997 13:35:52 -0800 Sean-Thomas -- I am quite impressed by your analysis of force-feedback, and the VBB feedback. This seems to be a very insightful piece of work, and as I study it more I am beginning to see what makes it tick. I'd like to review my understanding of a few of the features of the VBB feedback. Please feel free to correct my errors and omissions. My assumption in building my force-balance system was to maximize gain around the feedback loop at all frequencies to try to keep the mass stationary. This allows a direct readout of acceleration that is flat with frequency, since it is proportional to the current in the feedback coil. It appears that the amount of feedback in your system is much less -- only enough to reduce the movement of the mass by about 2:1 for long-period signals. And the predominant feedback path is through a differentiator in the frequencies of interest. Since the feedback current is still proportional to acceleration of the mass by the earth, and since the feedback current is the differential of the output of the displacement transducer, the output of the displacement transducer is, by definition, velocity. This has the advantage of having a direct velocity output, whereas my system requires additional integration stages to derive velocity from the acceleration signal, with the associated increase in noise and drift. Another interesting feature is the feedback path through the integrator. This has the effect of raising the loop gain at low frequencies and provides a high-pass filter for the velocity output, and helps keep the mechanical system centered. There is one thing I am not sure about. It seems that in the system you described the gain of the displacement transducer is rather high. Have you calculated the saturation level of the transducer in terms of earth velocity or in terms of event magnitude and distance? Also, WRT feedback coil sensitivity and resistance in a VBB system, couldn't one use an amplifier to drive the coil if it wasn't sensitive enough? Understanding, of course, that there would be more noise introduced into the system. Given the numbers from my system, you pointed out that I should reduce the mass to better match the feedback coil I have. Could I apply an amplifier to bring these back into equality? Thanks Sean-Thomas, for your analysis and for sharing it with the group. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: VBB Feedback Date: Tue, 30 Dec 1997 21:39:31 -0600 (CST) Karl and co, Karl, Our mail passes in the dark, or wherever internet mail goes. I just sent you: (in case you didn't get it.): Karl, I think I told you already that I have have made a pass at a transfer function for a 40 second To for your instrument with these parameters: r = 212 800 V/M (requires 20x gain after your LVDT), Gn = 5.1N/A (for your main coil), M = 0.3kg (much reduced from your 2.27kg, or 5lb, but needed for the flatness to 10 hz, with damping at 0.69), C= 16 uf, Rp = 361K ohms, RI = 127K, Rf = 7 ohms, TI = 20 seconds, and To = 4 seconds. This gives a response of 3685 volts/m/sec, flat from 40 seconds to 10 hz. Maybe these will be helpful for your new vertical. I wasn't sure if I sent all the numbers before. Regarding your analysis of the VBB feedback, it is pretty good on most points. I tend to rely on the mathematical model as strongly as the engineering intuition to understand what is going on. As I have mentioned before, the feedback is still a summation of currents into the force coil, NOT voltages. So inserting a voltage amplifier between the feedback elements and the coil will not produce a VBB response. Maybe a "Norton" current amp might work, but unless the differential and integral currents can both be controlled by their circuit elements, their effect will be nil. In the transfer function, the flat response occurs when the differential feedback dominates at less than To with the same magnitude that the integral feedback dominates below To. In fact, this creates an oscillator right AT To, so the proportional current through Rp is needed to damp the system, which will actually oscillate if Rp is open. Regarding the relative DC or static mass movement (as compared with the dynamic movement, which is much less): it is controlled by both the proportional and integral currents, and depends on the sensitivity of the mechanical suspension restoring force, which ideally would be zero and the period infinite. However, in a stable instrument it is handy to have the mass come to an equilibrium position, which is even more useful since the restoring force also aids in dealing with significant temperature effects. So the mechanical restoring force is finite but small, meaning that the feedback will allow some DC movement of the mass. This amount is easily determined by measuring the displacement output with the feedback on as well as off. On the prototype here, the ratio is about 10 to 1. This also means that if I determine the sensitivity of my 5-turn calibration coil (using the VRDT with the feedback off) to be 25 nanometers / microamp (it is actually 26.4), the mass only moves 2.5 nm /uamp. I need a step current of 30ua to produce a voltage of about 100 mv (peak pulse voltage) at the VBB output, which is equilavent to an actual step movement of the mass of 12 nanometers. Naturally, if the feedback perfectly controlled the static position of the mass, a step calibration would not work except for the transient time of Td. Regarding the sensitivity of the displacement transducer: with a sensitivity of say 50mv/micron and a 10x amp, it is 0.5 Volt/micron, or 500V/mm, or 500 000 Volts/meter. Sounds like a lot, until you realize that we are trying to measure 10**-10 meter, or 0.1 nanometer, which would have a voltage of only 5 microvolts, which is near the low noise limit of even high quality amplifiers. With my prototype here, the VBB output is about 3200 V/M/sec, but the 6-second microseisms come in at only 1 to 5 millivolts. And it took the M 7.7 in Tibet to clip the 12-bit digitizer here at 200mv. My maximum output is 7 volts, so I need the 16-bit ADC; actually, if my noise floor IS 5 microvolts, I have a dynamic range of 122.9db, which would take a 20-bit ADC to resolve. And conversely, a peak of 7 volts is a peak velocity of 2.18mm/second, or a pretty good shake (you can feel 10 microns/ second). In terms of earthquake magnitude, if we have a Mb3.0 at 110km (1 deg), and Mblg = 3.75 + 0.9*log[DELTA](degrees) +log[A](microns), the amplitude is 0.178 microns (at 1 hz). A magnitude 5 at the same distance would have an amplitude of 17.8 microns. And finally, regarding the size of the mass: larger is better if you have a powerful feedback coil, like the 90N/A in the S5000 with the ll kg mass, but the commercial VBB sensors have masses from 0.3 to 0.6 kg, with force coils around 20N/A for more high frequency output. If I model your sensor with the 2.7kg mass, the response is a rounded bump, much like a narrowband LP seis; the feedback currents simply cannot control it. The response is nicely broad and flat with the 0.3kg mass. I hope that I have answered your questions. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Notice the 3 SAF M3's... Date: Wed, 31 Dec 1997 06:45:45 -0800 (PST) But, did you notice the M4.1 this morning? I wonder who is not getting any sleep over that scenario? Frank Condon mail to:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" PS. I think I'm catching the "Quakey-Achey-Breaky Flu." >Golly, did you notice the trio of M3's along the locked southern portion >of the San Andreas fault at the Salton Sea? They occurred north of the >Obsidian Buttes where activity is relatively common. These events are >the first in this magnitude range here in some time. The Coachilla >Valley segment last ruptured in 1690. > >-- >Charles P. Watson, Consulting Geologist >Advanced Geologic Exploration / Seismo-Watch >Voice: 702-852-0992 / Fax: 702-852-3226 >mailto:watson@................ >http://www.seismo-watch.com > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Notice the 3 SAF M3's... Date: Wed, 31 Dec 1997 07:44:03 -0700 Oh my! That poor locked segment is feeling the strain... The M4.1 and the M3 aftershock are ~4 miles closer to Niland than the previous events. That's good. The Obsidian Buttes area often receives swarms of activity but furthern northwest, towards Mecca, is not so good. The Coachilla Valley segemnt of the San Andreas fault has not ruptures since 1680 and there might be a tight wire there. -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Oil damping of the Lehman Date: Wed, 31 Dec 1997 10:48:36 -0500 Hi gang, The damper for my Lehman (period about 25") has always been a vane attached to the boom. The vane is partially immersed in a pan of oil and= the amount of damping was adjusted by changing the oil level so that more= or less of the vane was in the oil. I found that the quickest way to meas. the period (and the amount of damping) during adjustments was to observe the boom motion with a microscope (about 30X) which has a scale in the eyepiece. A push was giv= en to the boom and the return motion was observed. = I observed that the boom motion was not like I would have expected--whe= n returning toward the equilibrium position, the boom traveled faster durin= g the first part of the motion and then slowed down for the last part (just= before reaching the equilibrium position). These tests were always with = a small motion, say 1/2 mm or less. I think that the fast early motion was caused by the oil "piling up" in= front of the vane during the push. This pile-up then applied more force = to the boom than if there had been sufficient time for the oil to flow aroun= d the vane. I thought that this seemingly non-linear damping was not good but ignored it. I have finally found a way to get easily adjustable damping without usi= ng a partially immersed vane. The idea is to have the vane totally immersed and simply rotate the vane = to change the damping-when the vane is perpendicular to the motion, the damping will be max. and when parallel, the damping will be min. With a totally immersed vane, I think that the resistance to motion will be proportional to the velocity and hence give the linear damping desired. The damper (which attaches to boom) is simply a 1/8" rod thru a mountin= g block. The bottom of the rod carries the vane and the top carries a pointer which rests on a calibrated scale. The scale has calibration mar= ks corresponding to the projected area (from 0 to one) of the vane in the direction of motion (cos of the rotation angle--45 deg is marked 0.7). = I found the proper vane size on the second try. The whole thing was easy = to make. I measured the damping by integrating (in Winquake) the records of boom= velocity. A constant (from test to test) push on the boom was produced b= y the meter-movement calibrator at four settings of the damper. I was astonsihed to get a nearly perfect straight line when % damping was plott= ed against the damper setting (per cos of angle)! The line does not pass th= ru zero which is correct since when the vane is paralled to the motion there= is still some viscous drag due to the vane and the shaft. Observing the motion with the microscope now shows what appears to be t= he proper exponentially-decaying-speed motion--not the two-speed stuff. = So I'm convinced that an oil damper should have the vane totally immersed. Happy new year! Bob Barns P.S. I'm glad to hear that the meeting was a great success and am sorry = to have missed it but such long flights seemed too uncomfortable. One suggestion:a meeting at some time other than heavy air travel might be good. = = _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Notice the 3 SAF M3's... Date: Wed, 31 Dec 1997 11:40:20 -0800 (PST) Hello Charles: Bombay Beach lives for another day! After getting out the maps and locating the faults in relation to the most recent activity, I believe your statement is correct. Isn't it kind of close to the cinder cones at Obsidian Butte? Could we be looking at the start of another geothermally active spot like Mammoth Lakes and Little Lake? Frank Condon mail to:frankcnd@.......... "Located in the seimic corridor somewhere between Fontana & Mammoth Lakes" >Oh my! That poor locked segment is feeling the strain... > >The M4.1 and the M3 aftershock are ~4 miles closer to Niland than the >previous events. That's good. The Obsidian Buttes area often receives >swarms of activity but furthern northwest, towards Mecca, is not so >good. The Coachilla Valley segemnt of the San Andreas fault has not >ruptures since 1680 and there might be a tight wire there. > >-- >---/---- >Charles P. Watson, Consulting Geologist >Advanced Geologic Exploration >Seismo-Watch / Earthquake Information Services >Voice: 702-852-0992 / Fax: 702-852-3226 >Office Location: 39.43N 119.71W >mailto:watson@................ >http://www.seismo-watch.com > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Notice the 3 SAF M3's... Date: Wed, 31 Dec 1997 11:59:59 -0700 Frank Condon wrote: > > Hello Charles: > > Bombay Beach lives for another day! After getting out the maps and locating the > faults in relation to the most recent activity, I believe your statement is > correct. Isn't it kind of close to the cinder cones at Obsidian Butte? Could > we be looking at the start of another geothermally active spot like Mammoth > Lakes and Little Lake? > Yes, Frank, it could, but an eruption would be rather unlikely. The Obsidian Buttes frequently has earthquake swarms, sometime, quite vigorous, and the last time a M4+ quake happened was way back in 1989. Yes, it is a geothermally active spot, as evident by the recent (Holocene) cinder cones. However, the likelyhood of the current sequence precipitating into an eruption is unlikely. It may continue much like the Cerro Prieto sequence in August where a few hundred M2+ events ralleyed for several weeks then dwindled away. My concern, rather, is the activity further northwest and along the Coachilla Valley fault segment. BTW: I start a new Seismo-Watch earthquake report in the Santa Barbara News-Press on Sunday and have been running a weekly feature in the Mammoth Times now for three weeks. The MT sponsor is Conservators Emporium, former makers of "Quake Wax" now called "Stay-Put". Legal problems with the former name, I gather. Cheers and Happy New Year! -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L)