From: Karl Cunningham Subject: Re: VBB feedback current Date: Tue, 30 Jun 1998 14:57:34 -0700 Sean-Thomas -- Thanks for all the information. I think I understand what you are saying about the feedback generating a current in the coil. It seems that if an amplifier has a low input impedance (to impersonate the impedance of the feedback coil), and if its output is a current from a high-impedance source (to impersonate the high impedance of the feedback components), I don't see why it wouldn't work. In other words, if one could place an ideal CURRENT amplifier in the line to the feedback coil, to magically boost the current to the coil while keeping everything else the same, would that not work? If so, then the problem is only to construct such a device. (And there are a lot of ways to connect up an op-amp). Since G of my new vertical will be about 4.7 (N/A-kg), I am planning to experiment with a current amplifier. And I am interested in methods to verify that the response is as desired. Please understand that I mean no disrespect, and I realize that you have a LOT more experience with seismic instrumentation than I do. But being one of those head-in-the-clouds engineer types who thinks that most of the world's problems can be solved with op-amps, I tend to question things I think I understand but don't make sense to me. (And I'd be even more of a pain if I were from Missouri ;). Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: Nuclear? tests? Date: Tue, 30 Jun 1998 17:34:36 -0700 (MST) On Tue, 30 Jun 1998, robert barns wrote: > Has solid evidence been presented that the Indian and/or Pakistani > "nuclear" tests were really nuclear events and not just large explosions of > conventional explosives? > Bob Barns Yes, they were nuclear. I am ashamed to admit that I can't remember who it was that posted some really cool EMPs recorded using some other device... ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ http://www.public.asu.edu/~hernlund/ "Enlightenment is man's emergence from his self-imposed immaturity. Immaturity is the inability to use one's understanding without guidance from another. This immaturity is self-imposed when its cause lies not in lack of understanding, but in lack of resolve and courage to use it without guidance from another. Sapere Aude! "Have courage to use your own understanding!"- that is the motto of enlightenment. -Immanuel Kant: "An Answer to the Question: What is Enlightenment?" ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: S-G period and Q Date: Tue, 30 Jun 1998 18:09:25 -0700 Hi Ed That's the way I understand it also. Barry Edward Cranswick wrote: > > Barry- > Having been forced to examine textbooks ("Mechanics", Symon; "Physics", > Resnick & Halliday) from physics classes I failed, I think that your > statements below confirm my belief that the frequency of a simple pendulum is > independent of its mass for all angles. Please correct me if I am wrong. > -Edward > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Nuclear? tests? Date: Tue, 30 Jun 1998 21:22:14 -0700 (PDT) Hi Guys: It was Charlie Plyler who captured those fantastic graphs with his ELF instrumentation. Yes, you can clearly see the EMP from the nuclear detonations. It is somewhat unclear as to how many indian tests were conducted from what is claimed. Frank Condon frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" >On Tue, 30 Jun 1998, robert barns wrote: >> Has solid evidence been presented that the Indian and/or Pakistani >> "nuclear" tests were really nuclear events and not just large explosions of >> conventional explosives? >> Bob Barns > > Yes, they were nuclear. I am ashamed to admit that I can't remember who it >was that posted some really cool EMPs recorded using some other device... > >****************************************************************************** > > John Hernlund > E-mail: hernlund@....... > WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ > http://www.public.asu.edu/~hernlund/ > >"Enlightenment is man's emergence from his self-imposed immaturity. >Immaturity is the inability to use one's understanding without guidance from >another. This immaturity is self-imposed when its cause lies not in lack of >understanding, but in lack of resolve and courage to use it without guidance >from another. Sapere Aude! "Have courage to use your own understanding!"- >that is the motto of enlightenment. >-Immanuel Kant: "An Answer to the Question: What is Enlightenment?" > >****************************************************************************** > > >_____________________________________________________________________ > >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: Greg Subject: Re: Nuclear? tests? Date: Tue, 30 Jun 1998 21:50:48 -0700 Frank Condon wrote: > It was Charlie Plyler who captured those fantastic graphs with his ELF Unless he's an employee of the Pakistan government and he faked the images ;) Conspiracy theory anyone? Encrypting my hard disk right now, Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Walt Williams" Subject: SETI SOHO -- CNN Report Date: Tue, 30 Jun 1998 23:41:21 +0000 ------- Forwarded Message Follows ------- From: "Walt Williams" To: seti@....... Date: Mon, 29 Jun 1998 22:32:52 +0000 Subject: SETI SOHO -- CNN Report Hello All, On 06-29-98, CNN (TV news 'channel'), after announcing Peter Sturrock's SSE 'UFO' scientific panel review and report, reported that "controllers lost contact with the Solar and Heliospheric Observatory" (SOHO) spacecraft. See: http://www.foxnews.com:80/js_index.sml?content=/scitech/062998/lostsat ellite.sml For information on the SOHO spacecraft see: http://wholesun.nascom.nasa.gov/index-text.html Walt Williams _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: robert barns <75612.2635@..............> Subject: Re: Nuclear? tests? Date: Wed, 1 Jul 1998 11:46:37 -0400 Hi, I have little knowledge about the production of EMP by nuclear tests bu= t I'm wondering if tests, esp. such small ones, produce EMP detectable at long distances. If so, would it have been enough for Plyler to detect? The 26 June issue of Science mag. and the July issue of Physics Today (which arrived yesterday) have extensive and very interesting technical articles about the tests. They both discuss seismic data in detail and conclude that the data conflict with many of the Indian and Pakistani claims. Neither mentions EMP observations. Hurry down to your library and look these up. Physics Today has other info. of interest to seismologists. Bob Barns Wear short sleeves! Support your right to bare arms! = _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: robert barns <75612.2635@..............> Subject: Re: Nuclear? tests? Date: Wed, 1 Jul 1998 11:46:37 -0400 Hi, I have little knowledge about the production of EMP by nuclear tests bu= t I'm wondering if tests, esp. such small ones, produce EMP detectable at long distances. If so, would it have been enough for Plyler to detect? The 26 June issue of Science mag. and the July issue of Physics Today (which arrived yesterday) have extensive and very interesting technical articles about the tests. They both discuss seismic data in detail and conclude that the data conflict with many of the Indian and Pakistani claims. Neither mentions EMP observations. Hurry down to your library and look these up. Physics Today has other info. of interest to seismologists. Bob Barns Wear short sleeves! Support your right to bare arms! = _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: Nuclear? tests? Date: Wed, 01 Jul 1998 13:03:37 -0700 (MST) On Wed, 1 Jul 1998, robert barns wrote: > I have little knowledge about the production of EMP by nuclear tests but > I'm wondering if tests, esp. such small ones, produce EMP > detectable at long distances. Yes, they sure can... > If so, would it have been enough for Plyler to detect? I think so. The problem is how the pulse is going to find its way around the globe, i.e. how will it propagate... Many portions of the earth at great depth are far too conductive to allow short wavelength propagation (must be ultra-long period), so that leaves mainly ionospheric reflection for the vast majority of the energy, similar to the transmission of strong radio. Some frequencies from the pulse will probably not behave in this manner, but EMPs are a mess that always has a matching frequency. If I had that file of Charlie Plyer's I would be interested in looking at the fourier spectrum to see how low the frequencies reach... > Neither mentions EMP observations. EMP observations are probably too often forgot by the public, however I think that they are used a lot more than we know about...and they will not appear in scientific journals much because there isn't a whole lot of prospects for exploiting it scientifically... ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ http://www.public.asu.edu/~hernlund/ "Enlightenment is man's emergence from his self-imposed immaturity. Immaturity is the inability to use one's understanding without guidance from another. This immaturity is self-imposed when its cause lies not in lack of understanding, but in lack of resolve and courage to use it without guidance from another. Sapere Aude! "Have courage to use your own understanding!"- that is the motto of enlightenment. -Immanuel Kant: "An Answer to the Question: What is Enlightenment?" ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: Nuclear? tests? Date: Wed, 01 Jul 1998 19:31:13 -0500 John Hernlund wrote: > > EMP observations are probably too often forgot by the public, however I think > that they are used a lot more than we know about...and they will not appear in > scientific journals much because there isn't a whole lot of prospects for > exploiting it scientifically... > John, This is not exactly EMP but have you heard of project HAARP? A huge HF transmitter in Alaska that can beam energy up into the ionosphere to cause local heating of the ionosphere. By proper scanning of the HF beam they expect to be able to generate ELF waves in the ionosphere. One use of the generated ELF waves is imaging of underground features, Such as faults and nuclear test facilities. An experiment using naturally occuring ELF has imaged the tunnel in Texas for the defunct accelerator project. HAARP has generated huge amounts of protests against this supposed "directed energy weapon". -- 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: Re: Nuclear? tests? Date: Thu, 02 Jul 1998 13:29:03 +1200 Yes Jim i know of it i recorded an excellect documentary about HAARP in late 1996 off the telly and as u say all about the out cries of a weapon weather control etc. very interesting all the same Dave >John, >This is not exactly EMP but have you heard of project HAARP? >A huge HF transmitter in Alaska that can beam energy up into the >ionosphere to cause local heating of the ionosphere. By proper scanning >of the HF beam they expect to be able to generate ELF waves in the >ionosphere. One use of the generated ELF waves is imaging of underground >features, Such as faults and nuclear test facilities. An experiment >using naturally occuring ELF has imaged the tunnel in Texas for the >defunct accelerator project. >HAARP has generated huge amounts of protests against this supposed >"directed energy weapon". >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: "frank murray" Subject: RE: (Fwd) SETI SOHO -- CNN Report Date: Wed, 1 Jul 1998 19:02:11 -0700 > On 06-29-98, CNN (TV news 'channel'), after announcing Peter > Sturrock's SSE 'UFO' scientific panel review and report, > reported that "controllers lost contact with the Solar and > Heliospheric Observatory" (SOHO) spacecraft. yes...the second major satellite to go bonkers, since folks started getting noisy about clinton sending satellite encryption and control tech to the chicoms...kinda looks like they're sending us a message... let's see now, how'd that intro on "the outer limits" go: "WE control the horizontal", "WE control the vertical"... frank _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Stovepipe Wells M4.7 Ubehebe Crater Date: Wed, 1 Jul 1998 23:31:49 -0700 (PDT) Hello All: What is your opinion about the recent seismic activity right near the old Ubehebe Crater in Death Valley? The depth was very shallow and seem to be epicentered very close to the crater. What is the historic record for the Ubehebe crater? Anything happened there over the past 500 years? Frank Condon frankcnd@.......... "Located in the Seismic Corridor Somewhere Between Fontana & Mammoth Lakes" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: New Mammoth EQ site Date: Wed, 01 Jul 1998 23:42:10 -0700 Fellow earthquake chasers, The Mammoth Times nespaper has asked me to put together a Seismo-Watch Earthquake Report for their web site. Before I submit it to them, I would like your comments to the following web page(s): http://www.seismo-watch.com/EQSERVICES/SeismoReports/MTSeismo/MTSeismo.html I know the graphics are a bit bulky and I will improve the bit density as time goes on. I also used a new jpg compaction method which seems to work well with my browser but I am unsure how it will work with others. Feel free to make some constructive comments and either post them here or send them to me directly. -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration/Seismo-Watch P.O. Box 18012, Reno, Nevada 89511 Voice: 702-852-0992 / Fax: 702-852-3226 mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Stovepipe Wells M4.7 Ubehebe Crater Date: Thu, 02 Jul 1998 00:00:29 -0700 Yea, I saw that too, Frank. A number of years ago, I mapped some of the active faults along the Death Valley-Furnace Creek fault system. Pretty impressive. Multiple displacements along a wide zone. I forget, but I think the Ubehebe Crater is on the west for the Cottenwood Mountains. There is a promintory ridge that comes down from Tin Mountain and the crater is off the northwest side. The DV-FC fault is on the east side of Death Valley, a few miles east from the Ubehebe Crater. There are a bunch of springs along the fault trace and that's where Scottys Castle is. The epicenter for the M4.7 looks like it is southwest of Scottys Castle near the defunct(?) Mesquite Spring. Mayby it'll start flowing again, eh? Kinda erie since the northern portion of the DV-FC fault in Fish Lake Valley had that M5.1 and subsequence robust swarm. Max credable eq for the DV-FC fault is ~M8. EeeeK! -- ---/---- Charles P. Watson Seismo-Watch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Walt Williams" Subject: The Sun Did It! Date: Thu, 2 Jul 1998 02:06:56 +0000 Frank, Please forgive me, this is off topic, one last time. The first satellite I could 'see' a possible link, whereas the SOHO is research craft which was built by the ESA and NASA to study the sun. If one were to visit the SEL archive at: gopher://proton.sec.noaa.gov:70/I9/plots/satenv/980627 gopher://proton.sec.noaa.gov:70/I9/plots/electron/980627 Maybe the sun fried it? Walt, 98.07.02 ============================================ ------- Forwarded Message Follows ------- From: "frank murray" To: "PSN-L Mailing List" Subject: RE: (Fwd) SETI SOHO -- CNN Report Date: Wed, 1 Jul 1998 19:02:11 -0700 Reply-to: PSN-L Mailing List > On 06-29-98, CNN (TV news 'channel'), after announcing Peter > Sturrock's SSE 'UFO' scientific panel review and report, > reported that "controllers lost contact with the Solar and > Heliospheric Observatory" (SOHO) spacecraft. yes...the second major satellite to go bonkers, since folks started getting noisy about clinton sending satellite encryption and control tech to the chicoms...kinda looks like they're sending us a message... let's see now, how'd that intro on "the outer limits" go: "WE control the horizontal", "WE control the vertical"... frank _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: The Sun Did It! Date: Thu, 02 Jul 1998 07:42:25 -0700 I received a Solar bulletin which said the craft was lost at 23:16 GMT 24 June. The anomalies on the GEOS Sat were on June 26. Pretty strong anomalies, though. -- ---/---- Charles P. Watson Seismo-Watch Walt Williams wrote: > > Frank, > > Please forgive me, this is off topic, one last time. > > The first satellite I could 'see' a possible link, whereas the SOHO > is research craft which was built by the ESA and NASA to > study the sun. If one were to visit the SEL archive at: > > gopher://proton.sec.noaa.gov:70/I9/plots/satenv/980627 > gopher://proton.sec.noaa.gov:70/I9/plots/electron/980627 > > Maybe the sun fried it? > > Walt, 98.07.02 > ============================================ > > ------- Forwarded Message Follows ------- > From: "frank murray" > To: "PSN-L Mailing List" > Subject: RE: (Fwd) SETI SOHO -- CNN Report > Date: Wed, 1 Jul 1998 19:02:11 -0700 > Reply-to: PSN-L Mailing List > > > On 06-29-98, CNN (TV news 'channel'), after announcing Peter > > Sturrock's SSE 'UFO' scientific panel review and report, > > reported that "controllers lost contact with the Solar and > > Heliospheric Observatory" (SOHO) spacecraft. > > yes...the second major satellite to go bonkers, since folks started > getting noisy about clinton sending satellite encryption and control > tech to the chicoms...kinda looks like they're sending us a message... > > let's see now, how'd that intro on "the outer limits" go: "WE control > the horizontal", "WE control the vertical"... > > frank > > _____________________________________________________________________ > > 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: "frank murray" Subject: RE: New Mammoth EQ site Date: Thu, 2 Jul 1998 09:38:19 -0700 hi charlie, well organized site...date is prominent, an item too often ignored...graphics are both pleasant to eye and info-rich...but one very slight problem: the depth chart gives the viewer the first impression that the recent series of quakes are within the caldera...i'm not sure that can be avoided without excessive section views or explanatory notes that would clutter up the site... good job, frank > Fellow earthquake chasers, > > The Mammoth Times nespaper has asked me to put together a Seismo-Watch > Earthquake Report for their web site. Before I submit it to them, I > would like your comments to the following web page(s): > http://www.seismo-watch.com/EQSERVICES/SeismoReports/MTSeismo/MTSeismo.html I know the graphics are a bit bulky and I will improve the bit density as time goes on. I also used a new jpg compaction method which seems to work well with my browser but I am unsure how it will work with others. Feel free to make some constructive comments and either post them here or send them to me directly. -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration/Seismo-Watch P.O. Box 18012, Reno, Nevada 89511 Voice: 702-852-0992 / Fax: 702-852-3226 mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "frank murray" Subject: RE: The Sun Did It! Date: Thu, 2 Jul 1998 09:56:08 -0700 walt wrote: > The first satellite I could 'see' a possible link, whereas the SOHO > is research craft which was built by the ESA and NASA to > study the sun. If one were to visit the SEL archive at: i agree that this is a bit off topic here, but on the other hand, earth watchers are likely to be decently informed on other matters of scientific interest...so i pose the question: anybody here know a source for info on the control of the SOHO??...specifically, were those same encryption algoritms used in it??... btw...i'd have thought that nasa would have hardened the craft to protect against the maximum reasonably expected sun blasts... frank _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: New Mammoth EQ site Date: Thu, 02 Jul 1998 10:03:56 -0700 Thanks for your comments, Frank. Yea, unsure how to make the activity in the Sierra terrain stand out differently than that in the caldera without a north-south x-section. maybe if I get a couple more sponsors, I can spend the extra time in making one. (hint-hint) Thanks again!! -- ---/---- Charlie Seismo-Watch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: lahr@.................. Subject: IASPEI Web Site Date: Thu, 2 Jul 1998 13:25:24 -0600 (MDT) The International Association of Seismology and Physics of the Earth's Interior (IASPEI) home page, located at http://www.seismo.com/iaspei/ may have some items of interest to PSN members, although I have not checked it out in depth. JCLahr ################################## John C. Lahr ################################# Seismologist ################################ U.S. Geological Survey ############################### Geologic Hazards Team, MS966 ############################## PO Box 25046 #############################/############################## ############################/############################### Denver, Colorado 80225-0046 ################################ Phone: (303) 273-8596 ################################## Fax: (303) 273-8600 ################################### lahr@........ ##################################### http://giseis.alaska.edu/lahr http://lahr.org/john-jan _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Walt Williams" Subject: PSNL - Re: Nuclear? tests? - HAARP Date: Thu, 2 Jul 1998 15:59:35 +0000 Hello, FYI. Regarding HAARP, there is much blah, blah, blah, but here is some of the good stuff. High-frequency Active Auroral Research Program (HAARP). Cut to the chase: Data Index: http://www.haarp.alaska.edu/haarp/data.html My favorite data: http://server5550.itd.nrl.navy.mil/projects/haarp/rioData.html (The 98 data seems to have disappeared?) HAARP Diagnostic: http://server5550.itd.nrl.navy.mil/projects/haarp/haarpDiag.html and the Main page: http://server5550.itd.nrl.navy.mil/projects/haarp/index.html Walt, 98.07.02 p.s. I am still working the problems of my Lehman seismometer. Flexure is a problem, now I think I know why everybody went with the short plate and the bricks. ========================================================== ------- Forwarded Message Follows ------- Date: Thu, 02 Jul 1998 13:29:03 +1200 To: PSN-L Mailing List From: "David A. Nelson" Subject: Re: Nuclear? tests? Reply-to: PSN-L Mailing List Yes Jim i know of it i recorded an excellect documentary about HAARP in late 1996 off the telly and as u say all about the out cries of a weapon weather control etc. very interesting all the same Dave >John, >This is not exactly EMP but have you heard of project HAARP? >A huge HF transmitter in Alaska that can beam energy up into the >ionosphere to cause local heating of the ionosphere. By proper scanning >of the HF beam they expect to be able to generate ELF waves in the >ionosphere. One use of the generated ELF waves is imaging of underground >features, Such as faults and nuclear test facilities. An experiment >using naturally occuring ELF has imaged the tunnel in Texas for the >defunct accelerator project. >HAARP has generated huge amounts of protests against this supposed >"directed energy weapon". >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) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: The Sun Did It! Date: Thu, 2 Jul 1998 16:59:25 -0700 (PDT) Hi Frank: Yeah, I think so too. That is a great possibility since we are having lots of CME's and proton streams headed towards us from the Sun. Thanks for the links! Unfortunately, I've heard that it will take a few years before they can replace it with another one. Frank >Frank, > >Please forgive me, this is off topic, one last time. > >The first satellite I could 'see' a possible link, whereas the SOHO >is research craft which was built by the ESA and NASA to >study the sun. If one were to visit the SEL archive at: > >gopher://proton.sec.noaa.gov:70/I9/plots/satenv/980627 >gopher://proton.sec.noaa.gov:70/I9/plots/electron/980627 > >Maybe the sun fried it? > >Walt, 98.07.02 >============================================ > > >------- Forwarded Message Follows ------- >From: "frank murray" >To: "PSN-L Mailing List" >Subject: RE: (Fwd) SETI SOHO -- CNN Report >Date: Wed, 1 Jul 1998 19:02:11 -0700 >Reply-to: PSN-L Mailing List > > > >> On 06-29-98, CNN (TV news 'channel'), after announcing Peter >> Sturrock's SSE 'UFO' scientific panel review and report, >> reported that "controllers lost contact with the Solar and >> Heliospheric Observatory" (SOHO) spacecraft. > >yes...the second major satellite to go bonkers, since folks started >getting noisy about clinton sending satellite encryption and control >tech to the chicoms...kinda looks like they're sending us a message... > >let's see now, how'd that intro on "the outer limits" go: "WE control >the horizontal", "WE control the vertical"... > >frank > > >_____________________________________________________________________ > >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: S-T Morrissey Subject: VRDT calibration Date: Thu, 2 Jul 1998 19:59:57 -0500 (CDT) Meredith, You asked about calibrating the VRDT or displacement sensor for the VBB instrument, particularly the setup I use. It is quite basic, consisting of a heavy base plate to hold the fixed coils of the sensor, and a micrometer mounted so that the moving pin of the micrometer moves parallel to the baseplate. In reality, my baseplate is a large SS pressure cap from a deep ocean seis case, about 4" in diameter with a dozen holes drilled around the perimeter. I mount the coils frame of the VRDT in one of these holes. Then I use the mounting bracket of the micrometer to set it up so that it moves across the baseplate parallel to the VRDT frame, or at a right angle to the gap of the transducer. Then I use a strip of 1/4" wide by about 1/32" thick brass shim stock to attach the moving vane of the VRDT to the moving pin of the micrometer. The strip is simply wrapped in a tight short spiral around the 1/4" dia micrometer pin (actually, it is first wrapped around a thinner rod so it will fit tightly), with the free end turned 90 degrees and the ferrous vane attached (solder or epoxy) to it. By jointly pivoting the VRDT frame and the micrometer on the baseplate, they can be adjusted so that the vane fits perfectly centered in the VRDT coils gap and moves axially within it as the micrometer is turned. This is a case where a picture is worth ,......! But I think you can figure it out. I pre-set the vane position for a maximum positive output, then turn the micrometer in small increments (10 microns with the differential Mitutoyo unit I have) through zero to the maximum negative output. I do this at the PC, so I can log the numbers (voltage at each setting) as I do it. I reverse the procedure to repeat the data set. This results in the inverted V style plot of the web page. The slightly snakey appearance of the data wrt the straight line is due to the differential thread error of the micrometer for each revolution. A similar procedure can also be used with the SG capacitive sensor, but I would leave it assembled to the boom. The micrometer could be fastened to the base so that it pushes the boom or mass as it is turned, with a small rubber band making sure that constant contact is made. On the STM vertical, the micrometer can be fastened to the central support post such that it pushes up on the boom as it is turned. If you don't have a micrometer, the space between the boom and the support post can be filled with a stack of 0.001" shim stock strips until the VRDT output is at zero, then one strip at a time can be removed or added to calibrate the displacement transducer. You also asked about the pressure case for the STM. I did buy a 20 gallon terrarium and was fitting a reinforced acryllic lid to it with a feed-through for the electrical ribbon cable through the plastic frame. But the project is on hold because I was invited to show the STM seismometer to the IRIS Education and Outreach Committee at the IRIS workshop at Santa Cruz next week. So I decided to build three "neat and tidy" copies of the second prototype, and to take the better two, one as an assembled instrument, and another to show details of the individual parts. But the first task though was to complete the mechanical drawing of the complete instrument, which required taking all the dimensions from the Beta prototype and spending lots of time using CAD to make an accurate scaled drawing of the whole unit. I am making the three new units from the dimensional information of the drawing, which, of course, brings out all the errors so I can correct them. After I am done and all the corrections are made, I will post it on the web. It is accurate enough to be scaled up with a copier to full scale to make patterns for cutting and drilling. (I will put a 1/2 scale version in the SASE you sent several months ago.) And of course, improvements are still being made, like a modification of the spring suspension that allows quite long mechanical periods (over 20 seconds). Regards, Sean-THomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: EarthQuake Subject: Re: The Sun Did It! Date: Thu, 02 Jul 1998 19:03:09 -0700 At 04:59 PM 7/2/98 -0700, Frank Condon wrote: >Hi Frank: >Yeah, I think so too. That is a great possibility since we are having lots >of CME's and proton streams headed towards us from the Sun. Thanks for the >links! This has been ongoing for years.........so why is it now just coming up as a possibility? I and others have suggested that this may be science........probable...repeatable etc...........yet we continue to call the 'fringe' group of folks eccentric????? Hello? Good Morning! Of course Frank this is nothing personal...I jsust took it as a jumping off point for myown ventures.......Always appreciate your input! As well as most of Larry group. Bob PS Yes I know this is a group message! _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Walt Williams" Subject: PSN-L Re: The Sun Did It! Date: Thu, 2 Jul 1998 19:08:52 +0000 Charles, Thanks. Since I posted the e-letter to the PSN-L I have been in touch with a SOHO team member. They are hoping to regain control of the spacecraft; not looking too good. The sun as most already know has been quite anomalous, lately. Walt, 98.07.02 dfheli@.............. http://www.pacificnet.net/~dfheli ------- Forwarded Message Follows ------- Date: Thu, 02 Jul 1998 07:42:25 -0700 From: watson@................ (Charles Watson) Organization: Advanced Geologic Exploration / Seismo-Watch To: PSN-L Mailing List Subject: Re: The Sun Did It! Reply-to: PSN-L Mailing List I received a Solar bulletin which said the craft was lost at 23:16 GMT 24 June. The anomalies on the GEOS Sat were on June 26. Pretty strong anomalies, though. -- ---/---- Charles P. Watson Seismo-Watch Walt Williams wrote: > > Frank, > > Please forgive me, this is off topic, one last time. > > The first satellite I could 'see' a possible link, whereas the SOHO > is research craft which was built by the ESA and NASA to > study the sun. If one were to visit the SEL archive at: > > gopher://proton.sec.noaa.gov:70/I9/plots/satenv/980627 > gopher://proton.sec.noaa.gov:70/I9/plots/electron/980627 > > Maybe the sun fried it? > > Walt, 98.07.02 > ============================================ > > ------- Forwarded Message Follows ------- > From: "frank murray" > To: "PSN-L Mailing List" > Subject: RE: (Fwd) SETI SOHO -- CNN Report > Date: Wed, 1 Jul 1998 19:02:11 -0700 > Reply-to: PSN-L Mailing List > > > On 06-29-98, CNN (TV news 'channel'), after announcing Peter > > Sturrock's SSE 'UFO' scientific panel review and report, > > reported that "controllers lost contact with the Solar and > > Heliospheric Observatory" (SOHO) spacecraft. > > yes...the second major satellite to go bonkers, since folks started > getting noisy about clinton sending satellite encryption and control > tech to the chicoms...kinda looks like they're sending us a message... > > let's see now, how'd that intro on "the outer limits" go: "WE control > the horizontal", "WE control the vertical"... > > frank > > _____________________________________________________________________ > > 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) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: New Mammoth EQ site Date: Thu, 02 Jul 1998 20:03:22 -0700 (MST) On Thu, 2 Jul 1998, Charles Watson wrote: > Thanks for your comments, Frank. Yea, unsure how to make the activity in > the Sierra terrain stand out differently than that in the caldera > without a north-south x-section. maybe if I get a couple more sponsors, > I can spend the extra time in making one. (hint-hint) Charles, Jonathan Lees at Yale has developed some cool software that makes viewing and constructing seismic activity cross-sections easy...you can download it from his page (I don't have the address right now but it shouldn't be difficult to find). ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ http://www.public.asu.edu/~hernlund/ "Enlightenment is man's emergence from his self-imposed immaturity. Immaturity is the inability to use one's understanding without guidance from another. This immaturity is self-imposed when its cause lies not in lack of understanding, but in lack of resolve and courage to use it without guidance from another. Sapere Aude! "Have courage to use your own understanding!"- that is the motto of enlightenment. -Immanuel Kant: "An Answer to the Question: What is Enlightenment?" ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: STM-8 new spring suspension and etc. Date: Thu, 02 Jul 1998 23:13:30 -0600 Sean-Thomas, Thanks for the detailed reply about the vrdt calibration, it all sounds good and clear too me. On the terrarium pressure case, with the acrylic lid, I presume you plan to have the lid on top/vertical? Probably the case weight was a factor along with the structurally weaker lid and its atmospheric pressure distribution along the top rim, away from the seismo. May need an anti-slide mechanism for the adjusting screws on the glass? We'll be looking forward to the new drawings of the STM-8 on the web. Actually, I'am glad I didn't start on the beta prototype mechanically, as any changes will be in the drawing and I'd have been out of date. Will the spring suspension improvement of over 20 seconds, be incorporated into the drawing; or is it too new thus far? That would be really something.....over 20 seconds....wow! Of course you know you've got to get that "published" fast-ha. Curiosity....I presume it changes the flexures; and, is it more or less stable than the old design, or is it yet to be made, or any other data? So....with the + 20 seconds, does this extend the vbb range significantly from 600 seconds upwards too? Boom the same length? Hope the IRIS workshop (etc.) goes very well, and they bestow alot of notoriety to your very significant contributions. Of course, I hope its very enjoyable there too. Have a good trip. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: New Mammoth EQ site Date: Thu, 2 Jul 1998 22:44:44 -0700 (PDT) Hello: Here is the URL for the software: http://love.geology.yale.edu/~lees/lees.html#lees.software Frank Condon frankcnd@.......... "Located in the seismic corridor somewhere between fontana & Mammoth Lakes" >On Thu, 2 Jul 1998, Charles Watson wrote: >> Thanks for your comments, Frank. Yea, unsure how to make the activity in >> the Sierra terrain stand out differently than that in the caldera >> without a north-south x-section. maybe if I get a couple more sponsors, >> I can spend the extra time in making one. (hint-hint) > >Charles, > Jonathan Lees at Yale has developed some cool software that makes viewing >and constructing seismic activity cross-sections easy...you can download it >from his page (I don't have the address right now but it shouldn't be >difficult to find). > >****************************************************************************** > > John Hernlund > E-mail: hernlund@....... > WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ > http://www.public.asu.edu/~hernlund/ > >"Enlightenment is man's emergence from his self-imposed immaturity. >Immaturity is the inability to use one's understanding without guidance from >another. This immaturity is self-imposed when its cause lies not in lack of >understanding, but in lack of resolve and courage to use it without guidance >from another. Sapere Aude! "Have courage to use your own understanding!"- >that is the motto of enlightenment. >-Immanuel Kant: "An Answer to the Question: What is Enlightenment?" > >****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: New Mammoth EQ site Date: Thu, 02 Jul 1998 23:36:59 -0700 Wooh-golly Frank! That's some mean 3-D GIS software! Now that I have had the chance to wipe the drool from my chin, I'll have to break out the ATM card and treat myself to a SUN Sparcstations running SUN OS-4.1.3. Gads! In my dreams! Hey, if you got another lying around, I'll pay the shipping. :> I'll keep the URL for when my ship does come in. Thanks! Nevertheless, I should show a N-S x-section. My modest Mac software can handle the data, it just takes time to generate it, which is a valuable commodity these days when there are other mountains to climb. Cheers! -- ---/---- Charlie Forever chained to a vintage Mac Performa. Frank Condon wrote: > > Hello: > Here is the URL for the software: > http://love.geology.yale.edu/~lees/lees.html#lees.software > > Frank Condon > frankcnd@.......... > "Located in the seismic corridor somewhere between fontana & Mammoth Lakes" > > >On Thu, 2 Jul 1998, Charles Watson wrote: > >> Thanks for your comments, Frank. Yea, unsure how to make the activity in > >> the Sierra terrain stand out differently than that in the caldera > >> without a north-south x-section. maybe if I get a couple more sponsors, > >> I can spend the extra time in making one. (hint-hint) > > > >Charles, > > Jonathan Lees at Yale has developed some cool software that makes viewing > >and constructing seismic activity cross-sections easy...you can download it > >from his page (I don't have the address right now but it shouldn't be > >difficult to find). > > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Greg Subject: Re: New Mammoth EQ site Date: Fri, 03 Jul 1998 09:15:17 -0700 Charles Watson wrote: > Wooh-golly Frank! That's some mean 3-D GIS software! Now that I have had the > chance to wipe the drool from my chin, I'll have to break out the ATM card and > treat myself to a SUN Sparcstations running SUN OS-4.1.3. Gads! In my dreams! The documentation page says, "The source code will be available in the future for easy porting to any X11 UNIX environment." Which probably means that with some effort you could get it to run under Linux. I have no idea how difficult it would be and I'm not anxious to try, becuase I have no need for it, but if you really wanted it... Linux for the Mac is a lot cheaper than a Sun (even a used Sun). Worst case scenario you have to prod some other people into helping you compile it for Mac Linux and you need a little more RAM/HD space to run Linux and MacOS on the same computer. If not, I've seen used (remanufactured) Sun workstations and servers on the onsale web site for well under $10,000 ;) A $4,000 dual Pentium II would probably be just as fast but oh well. Just a thought, Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: angel Rodriguez Subject: Can this gizmo work? Date: Fri, 03 Jul 1998 12:36:22 -0400 Members of the list, I live and play in Panama (8,47 N by 82,41 W) and just lately have gotten interesed in this wonderful hobby. I have a vertical instrument that works well and am building several others. I keep time by reading the output of a handheld GPS. The other morning I made a gizmo and posted its photo on http://www.chiriqui.com/photo It's a 10k jpg. It's basically a horizontal device with a vertical pendulum but could easly be a Lehman type. The hinge is a piezo element that I took out of a broken phone. With my voltmeter I get quite a range of +- millivolt even with the slightest motion. My question is: Is this use of a piezo out to lunch? Has it been done and not proven useful? I don't want to waste my time, but if I can build useful cheap devices, why not. Any comment would be very welcome. Angel Rodriguez _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: New Mammoth EQ site Date: Fri, 03 Jul 1998 13:49:46 -0700 Thanks for the suggestions. I saw the line for Linux but had never known what it was. I would like to first upgrade my work station with a new Apple G-3 300 Mhz and from there expand back into the PC platform, with a UNIX machine operating all the core data retrevial and processing. As I have read here and elsewhere, I could really use a few operating systems around the office which are networked together. Come to think of it, I could really dream of some pretty neat setups. Got to start somewhere! My earthquake reporting busines is really at the critical state where I could really use some employees, but the finacial end of it hasn't caught up with it yet. I do all the the work, sometimes putting in 6-7 days a week 10-16 hours a day. I'll need to clone myself in order to get the work for free and make the extra money to aquire the hardware/software upgrades. Newspapers really don't have any money and making the eq reporting busines to work was really just a shot in the dark anyway. I like to do it but there is little financial reward doing the work. Been there, done that, eh? So after reaching the break point a year ago, I decided to make that jump. I submitted a proposal to NEHRP this year to see if they would assist in the financial go of it. Should know in a couple weeks if I was a successful canidate. I hope so. I see a lot I could do with more resources but more importantly, getting appropriately compensated for the work. If the proposal doesn't work out, then it's back to the drawing board and consider the losses. Charlie Seismo-Watch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: New Mammoth EQ site Date: Fri, 03 Jul 1998 15:32:59 -0700 (MST) On Fri, 3 Jul 1998, Greg wrote: > Charles Watson wrote: > > Wooh-golly Frank! That's some mean 3-D GIS software! Now that I have had the > > chance to wipe the drool from my chin, I'll have to break out the ATM card and > > treat myself to a SUN Sparcstations running SUN OS-4.1.3. Gads! In my dreams! > The documentation page says, "The source code will be available in the > future for easy porting to any X11 UNIX environment." Which probably > means that with some effort you could get it to run under Linux. I have > no idea how difficult it would be and I'm not anxious to try, becuase I > have no need for it, but if you really wanted it... Linux for the Mac is > a lot cheaper than a Sun (even a used Sun). Worst case scenario you have > to prod some other people into helping you compile it for Mac Linux and > you need a little more RAM/HD space to run Linux and MacOS on the same > computer. Lees uses linux running some kind of xwindows platform for this program. ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ http://www.public.asu.edu/~hernlund/ "Enlightenment is man's emergence from his self-imposed immaturity. Immaturity is the inability to use one's understanding without guidance from another. This immaturity is self-imposed when its cause lies not in lack of understanding, but in lack of resolve and courage to use it without guidance from another. Sapere Aude! "Have courage to use your own understanding!"- that is the motto of enlightenment. -Immanuel Kant: "An Answer to the Question: What is Enlightenment?" ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: New Mammoth EQ site Date: Fri, 3 Jul 1998 17:47:41 -0700 (PDT) Hi charlie: I guess it is a little way out there for the average user... I'm still using the freeware software authored by Dr. Alan Jones (SUNY)named "Seismic" on my PC for tracking events. It does 3d graphs, too. My favorite ones are the plots for the Northridge Earthquake & aftershocks. But, I have been known to use a defunct Delorme Windows program named "Map-Expert" (2d) for precise locations (One-step up from US Atlas). A new tool that I'm currently learning to use is Maptech's TopoScout for WIN95. But it's Not a 3d program and it gives elevation gains for hikers and burros. Sorry, I'm not sure if there is a MAC equivalent for any of these. BTW I own a Mac-Plus that is still used ocasionally. Frank... frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" >Wooh-golly Frank! That's some mean 3-D GIS software! Now that I have had the >chance to wipe the drool from my chin, I'll have to break out the ATM card and >treat myself to a SUN Sparcstations running SUN OS-4.1.3. Gads! In my dreams! >Hey, if you got another lying around, I'll pay the shipping. :> > >I'll keep the URL for when my ship does come in. Thanks! > >Nevertheless, I should show a N-S x-section. My modest Mac software can handle >the data, it just takes time to generate it, which is a valuable commodity these >days when there are other mountains to climb. > >Cheers! > >-- >---/---- >Charlie >Forever chained to a vintage Mac Performa. > >Frank Condon wrote: >> >> Hello: >> Here is the URL for the software: >> http://love.geology.yale.edu/~lees/lees.html#lees.software >> >> Frank Condon >> frankcnd@.......... >> "Located in the seismic corridor somewhere between fontana & Mammoth Lakes" >> >> >On Thu, 2 Jul 1998, Charles Watson wrote: >> >> Thanks for your comments, Frank. Yea, unsure how to make the activity in >> >> the Sierra terrain stand out differently than that in the caldera >> >> without a north-south x-section. maybe if I get a couple more sponsors, >> >> I can spend the extra time in making one. (hint-hint) >> > >> >Charles, >> > Jonathan Lees at Yale has developed some cool software that makes viewing >> >and constructing seismic activity cross-sections easy...you can download it >> >from his page (I don't have the address right now but it shouldn't be >> >difficult to find). >> > >> > >_____________________________________________________________________ > >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: bob ogburn Subject: Re: Can this gizmo work? Date: Fri, 03 Jul 1998 19:57:42 -0700 Angel, I built several piezo sensors several years ago using elements from a product called a "flutter fan". The sensors were used to detect rapid vertical displacement (P waves) and they seemed to work well. I suspect the sensor you created will also be most useful for short period events due to the 'stiffness' of the hinge. bob ogburn Daly City, CA PSN angel Rodriguez wrote: > Members of the list, > > I live and play in Panama (8,47 N by 82,41 W) and just lately have gotten > interesed in this wonderful hobby. I have a vertical instrument that works > well and am building several others. I keep time by reading the output of a > handheld GPS. > > The other morning I made a gizmo and posted its photo on > http://www.chiriqui.com/photo It's a 10k jpg. > > It's basically a horizontal device with a vertical pendulum but could easly > be a Lehman type. The hinge is a piezo element that I took out of a broken > phone. With my voltmeter I get quite a range of +- millivolt even with the > slightest motion. My question is: Is this use of a piezo out to lunch? Has > it been done and not proven useful? I don't want to waste my time, but if I > can build useful cheap devices, why not. > > Any comment would be very welcome. > > Angel Rodriguez > > _____________________________________________________________________ > > 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: [Fwd: Re: Daily Summary of Solar Geophysical Activity for 27 June] Date: Sat, 04 Jul 1998 11:57:25 -0700 FYI -- ---/---- cpw From: "Walt Williams" Subject: A SOHO Status Report Date: Sat, 4 Jul 1998 12:45:02 +0000 Charles, Thank you. Walt Williams, 98.07.04 Best 4th to the USAers of the List =================================== Date sent: Sat, 04 Jul 1998 11:57:25 -0700 From: watson@................ (Charles Watson) Organization: Advanced Geologic Exploration / Seismo-Watch To: Subject: Daily Sum'ry of Solar Geophysical Activity for 27 June Send reply to: PSN-L Mailing List FYI -- ---/---- cpw ======================================================= ------- Forwarded Message Follows ------- From: Cary Oler Subject: Re: Daily Summary of Solar Geophysical Activity for 27 June To: watson@................ (Charles Watson) Date: Fri, 3 Jul 1998 16:17:16 -0600 (MDT) > What is the status of SOHO. > Did they get it back up and running? Not yet, but they're hopeful. I've appended below the status report that we provided with yesterdays daily summary of solar and geophysical activity (which you should receive in the next few hours - our system is busy sending out all of the older stuff and it may take a few hours to begin posting the recent material). Best regards. -Cary Oler Oler@.................. Oler@......... Oler@............... or COler@.................. SOHO SPACECRAFT UPDATE ---------------------- Controllers are still attempting to regain contact with the Solar and Heliospheric Observatory spacecraft. Contact was lost on 24 June during routine maintenance activities. There apparently were several emergency safe modes activated on the spacecraft prior to the loss of telemetry. Controllers now believe the spacecraft is tumbling in a spin mode that is preventing sunlight from reaching the solar panels sufficiently to charge the batteries to allow the spacecraft to transmit and receive ground commands. Fortunately, if this assessment is correct and if the assumed spin is correct, the orientation of the spacecraft to the Sun may change over the next few weeks to permit enough sunlight to charge the batteries and allow ground controllers to determine the problems and possibly regain control. In the meantime, a board is being convened to investigate the loss of contact in greater detail. European Space Agency ground stations in Europe have now joined the effort to help regain telemetry from the spacecraft. This is in addition to the Deep Space Network radio telescopes which have been trying since the incident occurred. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "frank murray" Subject: RE: [Fwd: Re: Daily Summary of Solar Geophysical Activity for 27 June] Date: Sat, 4 Jul 1998 13:13:46 -0700 charlie forwarded: >....................Contact was lost on 24 June during >routine maintenance activities. There apparently were >several emergency safe modes activated on the spacecraft >prior to the loss of telemetry................. hmmm...i'd like knowing more about those "emergency safe modes" and their activation...is this a reference to self protective routines that the bird was designed to go into when subjected to heavy sun blasts, to partial system failure, or to "illegal" communication attempts??...systems i've helped install at secure institutions typically go into "emergency safe modes" when any operator attempts to access levels of the system above that operator's authorization... if this is all too far off topic for this list, i'm open to private e-mail from any that might wander across further info on what happened to either the HALO or that geo-sychro bird... thanks again, charlie frank _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Keith Payea Subject: Parts Source Date: Sun, 5 Jul 1998 18:54:19 -0400 I've been considering the construction of one of Sean Thomas's vertical units, and I "re-discovered" a source for some of the parts, especially t= he brass shim stock. The outfit is "Small Parts, Inc.", 1-800-220-4242 139= 80 NW 58th Court, PO Box 4650, Miami Lakes, FL 33014-0650. They have all o= f the aluminum extrusion shapes, stainless hardware, and the troublesome sh= im stock in sizes from 0.001" to 0.031" thick. A 6" by 9" piece of the 0.00= 5" stock is only $3.69. They have a $15.00 minimum, but that won't be a problem once you see the catalog! They even have some titanium hardware like machine screws and 1/4-20 threaded rod. Good Luck, Keith Keith Payea Port Hadlock Design Group phdg@.............. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Greg Subject: Re: Parts Source Date: Sun, 05 Jul 1998 20:20:20 -0700 Keith Payea wrote: > brass shim stock. The outfit is "Small Parts, Inc.", 1-800-220-4242 13980 I spend too much time on the internet... I found the URL for those of us not planning on visiting the store anytime soon. Not that they probably wouldn't send a catalog in the mail. ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Erich F. Kern" Subject: Re: Parts Source Date: Sun, 5 Jul 1998 20:53:51 -0700 Greg, I've no idea what you've just said. What does spending time on the internet have to do with Greg's post???? Erich > From: Greg > To: PSN-L Mailing List > Subject: Re: Parts Source > Date: Sunday, July 05, 1998 20:20 > > Keith Payea wrote: > > > brass shim stock. The outfit is "Small Parts, Inc.", 1-800-220-4242 13980 > > I spend too much time on the internet... I found the URL for those of us > not planning on visiting the store anytime soon. Not that they probably > wouldn't send a catalog in the mail. > > ,Greg > > _____________________________________________________________________ > > 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: Greg Subject: Re: Parts Source Date: Sun, 05 Jul 1998 21:10:53 -0700 Erich F. Kern wrote: > I've no idea what you've just said. What does spending time on the internet > have to do with Greg's post???? Not a lot really. I just happen to be online when the message arrived and I read through it and searched for the company and posted all in one session. In fact, I haven't hung up yet. By the way, I'm Greg and I was only criticizing myself. It's not the first time it's happened. A while ago someone posted info about an electronics surplus compnay from Scottsdale, AZ? and I found the URL for it as well. It's probably in the mailing list archive files. Also I think I may have found the URL for Gateway Electronics. I hope that makes more sense. I should really hang up now, Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Greg Subject: Re: Parts Source Date: Mon, 06 Jul 1998 10:19:58 -0700 Can I blame it on the internet as well? I was up too late? Not enough caffiene in my diet? Should have been dusting the furniture instead? http://www.smallparts.com/ http://www.gatewayelex.com/ Sorry, I forgot the name of the third one. And I didn't bookmark it. ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: longer period of STM vertical Date: Mon, 6 Jul 1998 19:27:57 -0500 (CDT) Meredith, Regarding your questions about the longer period of the STM vertical. It turns out that the width and thickness of the original flexures of the leaf spring was limiting the mechanical period: ie. some of the rigidity of the spring ends was coupled into the system. In the BETA unit I had experimented and cut the lower flexures to 1/2" wide, and a 4 second period was obtainable as the upper spring support frame contact at the boom was moved toward the boom hinges. For the three new GAMMA units, I tried making the working width of both the upper and lower flexures only 1/4" wide (the soldering area is still 3/4" wide). Since the flexures are in tension, this is not a strength problem, but makes them easier to damage by excessive bending. THe thinner suspension further decouples the torques of the spring end as the boom moves and changes the angle of the spring restoring force. The period is adjusted by moving the upper spring support bar towards the hinges. A change of about 12 mm will vary the period from 2 seconds to infinity (ie. instability). Since the mechanical period affects the damping of the VBB system, the advantage of greater sensitivity or longer electronic period is traded off for a more stable mechanical period, like 6 to 10 seconds. There is still room for experimentation here. I am still packing up the new seismometers for the IRIS meeting at Santa Cruse, so I probably will not be able to post the new drawing of the seismometer until later in the month. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Home brew "speaker" magnetic enhancement Date: Mon, 06 Jul 1998 19:39:28 -0600 Hi all, If you're familar with speaker magnet construction, you might be interested in this approach of a homebrew speaker voice coil magnetic enhancement. Basically all speakers are shaped somewhat like a open ended can with a center pole welded inside on the bottom surface and extending up to a donut magnet with its space gap from the center post. Atop this is usually a donut shaped ferrite magnet. My unit has the same construction, but the only single change, was the addition of a neodymium magnet on the bottom of the container back plate. Then, the center post is sat on top of the neo. The strength of the 2 pole neo magnet is about 14K, while the ferrite donut magnet above is maybe less than 1K....depending on gap spacing. I plan on epoxying the center post to the magnet, but not to the back plate...this will allow movement for centering. The neo magnets power precludes any need for mechanical attachment. I do use a flat sheet metal backplate and a magnetic metal tube to extend the height of the assembly...which is normal. Of course the gap strength is really enhanced....maybe 5-10 times. No gaussmeter to check here though. The only interesting result other than the increased field I've seen, is that while normally the docut and center pole have equal attraction to metal, now; the neo takes over. So if you were to run a small screwdriver along the ferrite gap, it would stay there, but if you were to slightly space it from the ferrite the center pole would grab it. My Sprengnethers use the same basic construction. They are more adjustable than a store bought speaker unit. All parts can be dissassembled. My homebrew is of the same construction. The neodymium magnet I used is about 1/2" thick X 1" X 5/8" wide. Not a common size. I would expect that any 2 pole magnet of the neodymium (or Samarium) variety, would show a large field gap increase over just a plain ferrite gap. Obviously whether its used for a pickup or a feed back assembly, the sensitivity/power is increased for the coil....which is separate. My unit is not at a final stage. I will have to adopt to any coil and of the diameter of the center pole will also have to be found. If the above already exists somewhere...I don't know of it...yet-ha. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Re: longer period of STM vertical Date: Mon, 06 Jul 1998 21:50:29 -0600 Sean-Thomas, Thanks for the reply on the longer period of your STM-Gamma unit. The period variation of 2 seconds too infinity really is fantastic for a vertical instrument! Well done Sean-Thomas! It almost sounds like with some electronic circuit and/or damping changes, it can attain long periods comparable too or over that of commercial units. Of course, I'am only guessing, but it would "seem" to be on the horizon. We'll be anxious to see the new drawings. Again, have a good time in Santa Cruz. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Re: longer period of STM vertical Date: Mon, 06 Jul 1998 21:50:29 -0600 Sean-Thomas, Thanks for the reply on the longer period of your STM-Gamma unit. The period variation of 2 seconds too infinity really is fantastic for a vertical instrument! Well done Sean-Thomas! It almost sounds like with some electronic circuit and/or damping changes, it can attain long periods comparable too or over that of commercial units. Of course, I'am only guessing, but it would "seem" to be on the horizon. We'll be anxious to see the new drawings. Again, have a good time in Santa Cruz. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Steve Hammond Subject: Status- Geosource MD-100 geophones Date: Mon, 06 Jul 1998 21:49:50 -0700 Electronics goldmine USA 1-800-445-0697 FAX 602-661-8259 Http://www.goldmine item # G9621 MD-100 geophone $8.95 each US I received my order over the weekend and everything is as expected. They are small and they work (I ordered 3) 14-hrz, 335 ohm coil, and appear to be used. I connected each up to the Lehman amp ciruit provided in the PSN documentation (Op27 configured with a gain of 221 and coax driver) and was pleased with the generated waveform. They look like they should work well for recording local events. I would have like to seen them shipped with the coil shorted however. I have installed one inplace of my one of my hs10's and will match the data to vertical and N/S to see how they perform in operation. Post the findings as I receive the data. Regards, Steve PSN San Jose _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Peter Subject: Geophone Date: Mon, 06 Jul 1998 23:04:14 -0700 I have been recording with one of the geophones from electronics gold mine. Its buried 2 feet deep in a paint can with sand and is quite sensitive. I pick up noise from a nearby construction site as well as a mystery event every 5:50am on week days only? Pete Fleming _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Brian Subject: LPT:Analog? Date: Tue, 07 Jul 1998 02:33:27 -0400 Some time ago, a company called ADNAV Electronics, was selling a low cost A/D adapter that pluged in to the printer port. Does any one know if this is still available somewhere as the company appears to be out of business. It was called the LPT:Analog! v2.0 and sold for US$59.00. Thanx in advance! Brian. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Charlie Rond Subject: Event? Date: Tue, 07 Jul 1998 15:17:29 -0500 Something coming in at Memphis: 7/7/98 - 20:15uct. Charlie Rond -\/\--Public Seismic Network-Memphis http://gandlf.ceri.memphis.edu/~rond/psn _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ken Navarre Subject: Re: LPT:Analog? Date: Tue, 7 Jul 1998 13:26:48 -0700 (PDT) On Tue, 7 Jul 1998, Brian wrote: > Some time ago, a company called ADNAV Electronics, was selling a low > cost A/D adapter that pluged in to the printer port. Does any one know if > this is still available somewhere as the company appears to be out of > business. It was called the LPT:Analog! v2.0 and sold for US$59.00. I have one of these lttle goodies. One problem is that is unipolar. I shoved a "D" cell battery in series with it to "load" it so I could get the semblance of a +/- data trace. Another problem is that it isn't supported by either EMON or SDR. I had to write a Qbasic program to view the data and still haven't gotten it to save the data to a file... :( So much for a "simple" portable solution for a field unit using a laptop... I'll check to see if I have the address (email or snail) for these guys. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ken Navarre Subject: Re: LPT:Analog? Date: Tue, 7 Jul 1998 13:30:39 -0700 (PDT) Ah, here is the address for ADNAV. I had it tucked safely away in my bookmark file... David & Dorith Prutchi (409)292-0988 or mail (58 Chicory Ct, Lake Jackson,TX 77566) Ken _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Rex Klopfenstein, Jr." Subject: PSN - Adjustment Screws Source Date: Tue, 07 Jul 1998 18:14:23 -0400 After missing the cheap adjusting screws referred to in the past, I decided to use 1/4-28 screws. Last week I found a source of "relative" inexpensive adjustment screws. THORLABS, Inc sells 1/4-80 & 3/16-100 adjustment screws. These come in lengths from 1" to 3" with and without knobs. They also sell brass matching nuts. What is nice with these screws is that they have steel balls staked into the end of adjustment screws. By the way, the screws vary in price from $6 to $9 for 1/4 units and the nuts are in the $6 to $8 range. They accept MC, VISA, or AmEx THORLABS, INC. 435 Route 206, PO Box 366 Newton, NJ 07860-0366 973-579-7227 973-383-8406 (FAX) http://www.throlabs.com -- Rex Klopfenstein, Jr. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Rex Klopfenstein, Jr." Subject: Re: PSN - Adjustment Screws Source Date: Tue, 07 Jul 1998 19:16:36 -0400 Rex Klopfenstein, Jr. wrote: > > http://www.throlabs.com <----WRONG!!! The correct URL is http://www.thorlabs.com Sorry, my fingers got ahead of my brain!!! > > > -- > Rex Klopfenstein, Jr. > > _____________________________________________________________________ > > 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: longer period of STM vertical Date: Tue, 07 Jul 1998 18:13:30 -0700 Sean Thomas Did moving the spring support closer reduce your mass much and consequently the gain. I'm sure there is a trade off in there, re. period vs gain. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Al Allworth" Subject: A Y2K compliance test program Date: Thu, 9 Jul 1998 23:26:35 -0700 Hi All A Y2K compliance test program can be found at: The manual method may not tell the whole story. Al _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: RE: A Y2K compliance test program Date: Tue, 07 Jul 1998 23:54:14 -0700 >From: "Al Allworth" >To: "Larry Cochrane" >Subject: RE: A Y2K compliance test program >Date: Thu, 9 Jul 1998 23:39:19 -0700 >X-MSMail-Priority: Normal >X-Mailer: Microsoft Outlook 8.5, Build 4.71.2173.0 >Importance: Normal >X-MimeOLE: Produced By Microsoft MimeOLE V4.72.3110.1 > > > >Hi all, > >Sorry, the url should be: www.nstl.com > > Al > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Francesco" Subject: LARGE EVENT NEAR AZORES ISLAND Date: Thu, 9 Jul 1998 17:19:51 +0200 05.19.07 UTC MB 6.1 Loc: ATLANTIC OCEAN - AZORES ISLAND 8 victims , many iniured e many material damnages I.ES.N. - PSN ITALY
05.19.07  UTC
MB 6.1
Loc: ATLANTIC OCEAN - AZORES = ISLAND
 
8 victims , many iniured e many = material=20 damnages
 
I.ES.N. - PSN ITALY
From: "Francesco" Subject: IRAN Date: Thu, 9 Jul 1998 17:26:17 +0200 14.18 UTC MB 6.0 Loc.: IRAN-ARMENIA-AZERBAIJAN BDR I.ES.N. - PSN ITALY
14.18  UTC
MB = 6.0
 
Loc.:  IRAN-ARMENIA-AZERBAIJAN BDR
 
I.ES.N. - PSN ITALY 
From: "David A. Nelson" Subject: LARGE Kermadec Sth PAC event Date: Fri, 10 Jul 1998 03:37:49 +1200 Hi all 15:30 utc, 9th july 98 and the surface waves are finally starting to die off S-P 3 minutes from Dunedin so event is jst Nth of the Kermadec Islands byeeeeeeee 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: Edward Cranswick Subject: Good luck in Santa Cruz Date: Thu, 09 Jul 1998 13:05:04 -0600 Larry & Merredith- I agree with Meredith: Good luck in Santa Cruz. meredith lamb wrote: Again, have a good time in Santa Cruz. -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: Stephen & Kathy Subject: BOOMs Date: Fri, 10 Jul 1998 18:52:41 -0700 Is there anyone in the Northern California area that is recording any Sonic Booms????? Sinse the 12 of June I have recorded, on approx 10 occasions, usually between 17:00 and 19:00 UTC, a series of 7 to 8 and on one occasion 14 BOOMs!! They are approx 15 sec apart!! I've contacted all the quarrys, the sheriffs dept., the forestry dept., the fire dept., several heavy construction contracters and no one can account for them!!! I'm still trying to determine if it could be a local mine or if I am picking up Sonic Booms from Nevada???? The last set that I recorded was this evening starting at approx (July 11, 98 00:27:40),, (July 10, 98 17:27:43 local PDT) Thanks in advance, Stephen Mortensen PSN Station #55 Pilot Hill Ca USA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert Avakian Subject: Re: BOOMs Date: Fri, 10 Jul 1998 20:28:40 -0700 I understand from relatives who live near Redding that there is an artillery or munitions base which shoots off rounds about that time. I even heard on or two this spring when I was there. Could this be what you are detecting? Avakian Stephen & Kathy wrote: > > Is there anyone in the Northern California area that is recording any > Sonic Booms????? Sinse the 12 of June I have recorded, on approx 10 > occasions, usually between 17:00 and 19:00 UTC, a series of 7 to 8 > and on one occasion 14 BOOMs!! They are approx 15 sec apart!! > I've contacted all the quarrys, the sheriffs dept., the forestry dept., > the fire dept., several heavy construction contracters and no one > can account for them!!! I'm still trying to determine if it could > be a local mine or if I am picking up Sonic Booms from Nevada???? > The last set that I recorded was this evening starting at approx > (July 11, 98 00:27:40),, (July 10, 98 17:27:43 local PDT) > Thanks in advance, > Stephen Mortensen > PSN Station #55 > Pilot Hill Ca 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: EarthQuake Subject: Re: BOOMs Date: Fri, 10 Jul 1998 19:14:42 -0700 At 06:52 PM 7/10/98 -0700, Stephen & Kathy wrote: >Is there anyone in the Northern California area that is recording any >Sonic Booms????? >The last set that I recorded was this evening starting at approx >(July 11, 98 00:27:40),, (July 10, 98 17:27:43 local PDT) >Thanks in advance, >Stephen Mortensen >PSN Station #55 >Pilot Hill Ca USA Stephen; A very interesting scenario. Although I am not a seimso owner, this AM as my kids were about ready to go to the aquatic center in Grand Forks BC., two major and I mean major sonic booms. First time I have heard them since I moved from Cleveland in 1976! These puppies were so huge they shook my one window open and almost rattled the big sunroom windows to shatters....First came one which got me right out of my seat..then another almost as you say about 10-15 seconds later. It took a bit but we knew what they were. FYI We live at apprx. 2100 ft in the Kettle Range at 48.9 N and I forget the Long but it is close to 118. The planes were flying together from N to S which means at that speed they had to cross over from Canada! The birds came RIGHT over our octagon cabin and the noise etc...really blew us away! Bob Shannon Pinpoint EQ News _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: EarthQuake Subject: Re: BOOMs Date: Fri, 10 Jul 1998 19:33:42 -0700 At 06:52 PM 7/10/98 -0700, Stephen & Kathy wrote: >Is there anyone in the Northern California area that is recording any >Sonic Booms????? Stephen; Could you please cross-post your original on this to my list? Pinpoint@.............. Thanks Bob _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Peter Subject: Missing Quake? Date: Fri, 10 Jul 1998 19:43:54 -0700 PSN, There was a quake on the usgs page: http://quake.wr.usgs.gov/recenteqs/ It was listed as a M4.1 at about 19:18:50 (the time it arrived here) on 7/8/98. The location was just off the coast of southern CA. The map showed it as a red box so it happened within the hour and should have been on the map for 7 days? Now its gone? I think I recorded it here in San Jose on my Lehman. I would not have noticed it was gone until a friend mentioned its disappearance? Anyone know what it was or why it is gone? Thanks, Pete Fleming _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "John Krempasky" Subject: Re: Missing Quake? Date: Fri, 10 Jul 1998 22:51:02 -0400 Here's a copied section of a post from Lucy Jones of the USGS found on ca.earthquakes on USENET: A similar thing happened with the "M4.2" off San Diego. It was really a M4.8 off Baja, but with no stations nearby the automatic system mislocated it. Lucy Jones USGS/Caltech - Southern California Seismic Network speaking for myself So, it was a mislocated quake by an automatic system. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen & Kathy Subject: Re: BOOMs Date: Fri, 10 Jul 1998 19:54:15 -0700 Robert Avakian wrote: > > I understand from relatives who live near Redding that there is an > artillery or munitions base which shoots off rounds about that time. I > even heard on or two this spring when I was there. Could this be what > you are detecting? > > Avakian > > Stephen & Kathy wrote: > > > > Is there anyone in the Northern California area that is recording any > > Sonic Booms????? Sinse the 12 of June I have recorded, on approx 10 > > occasions, usually between 17:00 and 19:00 UTC, a series of 7 to 8 > > and on one occasion 14 BOOMs!! They are approx 15 sec apart!! > > I've contacted all the quarrys, the sheriffs dept., the forestry dept., > > the fire dept., several heavy construction contracters and no one > > can account for them!!! I'm still trying to determine if it could > > be a local mine or if I am picking up Sonic Booms from Nevada???? > > The last set that I recorded was this evening starting at approx > > (July 11, 98 00:27:40),, (July 10, 98 17:27:43 local PDT) > > Thanks in advance, > > Stephen Mortensen > > PSN Station #55 > > Pilot Hill Ca USA At this point it could be most anything!! If no one else is recording them, then I will go back to looking for something local. If anyone needs more specific times I can give them!! Thanks for the reply, Stephen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: EarthQuake Subject: Re: BOOMs Date: Fri, 10 Jul 1998 20:22:15 -0700 At 07:54 PM 7/10/98 -0700, Stephen & Kathy wrote: >At this point it could be most anything!! If no one else is recording >them >then I will go back to looking for something local. If anyone needs >more >specific times I can give them!! FYI My times are not specific but my wife did make mental notes, as it was such an unusual occurence. Between 11:30AM and 12:15PM PCT. I thought this was a no-no....sonic stuff over populated areas.... I realize Larry attempts and succeeds at keeping this a very focused group, but I think those who have had this happen in the past few days may find it at least indirectly related. Bob Pinpioint _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Arie Verveer Subject: One Degree ? Date: Sat, 11 Jul 1998 18:47:05 +0800 Hi, I plan to generate a Travel time table for West Australia that can be used with Winquake. I'll be using a set of tables given to me by the local geophysical observatory. (time verses distance.) But the tables used by Winquake are in degrees verses time. The question is: What is a degree? Is a degree based on the geoid height or do you need to compensate for the shape of the earth? Any help would be appreciated. Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Kermadec Islands Quake Lr-Lq Attenuation Date: Mon, 13 Jul 1998 09:04:29 -0600 Hi All, Am questioning the Kermadec Islands 6.3 quake of 7/9/98, which occurred at 14:45:26. Why do all the records from many amateur sources have such large P & S traces, and the LR-LQ traces have such low amplitudes? Even the records of instruments of longer period (~15 seconds up), show little amplitude. It occurred at normal depth. Alot of quakes around other ocean areas are not so affected. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Kermadec Islands Quake Lr-Lq Attenuation Date: Tue, 14 Jul 1998 07:30:02 +1200 At 09:04 AM 7/13/98 -0600, you wrote: >Hi All, >Am questioning the Kermadec Islands 6.3 quake of 7/9/98, which >occurred at 14:45:26. Why do all the records from many amateur >sources have such large P & S traces, and the LR-LQ traces have >such low amplitudes? Even the records of instruments of longer >period (~15 seconds up), show little amplitude. It occurred at >normal depth. Alot of quakes around other ocean areas are not so >affected. >Thanks, Meredith Lamb Thats easy meredith, cuz the quake was not nornal depth its was ~250 km deep, the NEIC record for this event was well out, the New Zealand seismological observatory with many closer in recorders, got a far more accurate location and depth calculation here is their info which is a far better fit to the data U.T.: 1998 July 9 14:45:57 NZST: 1998 July 10 2:45:57 a.m. Lat, Long: 32.05S 176.39W Location: 341 km south-south-east of Raoul Island Focal depth: 250 km Magnitude: ML 6.5 U will also notice that there is a huge difference in location as well... 2 degrees (222km) further south and 3 degrees (333km) further west than the NEIC records. It was only when I got this data did my P and S arrivals make sense cuz I could see that the quake was somewhat closer to me that the NEIC indicated. The real problem lies in that they (NEIC) have only a few stations is this part of the world and as a result their locations, etc are often a long way out. They often locate events off shore of NZ that are really in the centre of either the North or South Island. Congrats. on ur noticing of the lack of large surface waves for such a sizeable event (Mw7.2) when I sat in front of my SDR and drum recorders and watched this event roll in, I also noted the low amplitude of the surface waves and said to myself hmmmmm a deep quake ! Take care 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 & Kathy Subject: major quake Date: Tue, 14 Jul 1998 21:57:16 -0700 Major Quake as I type Stephen Pilot Hill Ca USA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen & Kathy Subject: second smaller quake Date: Tue, 14 Jul 1998 22:00:28 -0700 A second smaller quake is rolling through Stephen Pilot Hill Ca _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Steve Hammond Subject: Re: second smaller quake Date: Tue, 14 Jul 1998 21:39:54 -0700 Tom's place 5.1 http://quake.usgs.gov/recenteqs/Maps/119-38.html Regards, Steve Hammond Stephen & Kathy wrote: > > A second smaller quake is rolling through > Stephen > Pilot Hill 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: Stephen & Kathy Subject: quake 3 Date: Tue, 14 Jul 1998 23:50:07 -0700 another small quake,,, probably about a 3.7 or 3.8 going off!! Stephen Pilot Hill _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen & Kathy Subject: quake 4 Date: Tue, 14 Jul 1998 23:54:16 -0700 And another one about the same size! Stephen Pilot Hill _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Canie Brooks Subject: Re: quake 3 Date: Tue, 14 Jul 1998 23:53:37 -0700 At 11:50 PM 7/14/98 -0700, Stephen & Kathy wrote: >another small quake,,, probably about a 3.7 or 3.8 going off!! >Stephen >Pilot Hill Here it is! == PRELIMINARY EARTHQUAKE REPORT == Rapid Earthquake Location Service U.S. Geological Survey, Menlo Park, California U.C. Berkeley Seismological Laboratory, Berkeley, California Version 2: Updates lower and earlier versions of this earthquake report This is a computer-generated message -- it has not yet been reviewed by a seismologist. A LIGHT EARTHQUAKE OCCURRED AT 11:46 PM PDT Tuesday, Jul 14, 1998. THE MAGNITUDE 4.1 (ML) EVENT IS LOCATED 7 MILES WSW OF TOMS PLACE, CA THE HYPOCENTRAL DEPTH IS 3.1 MILES. PRINCIPAL EARTHQUAKE PARAMETERS _______________________________ Magnitude : 4.07 ML Event Date & Time : 07/14/1998 11:46:32 PM PDT 07/15/1998 06:46:32 UTC Location : 37.5345 N, 118.8125 W : (37 deg. 32.07 min. N, 118 deg. 48.75 min. W) Depth : 5.0 km. deep ( 3.1 miles) Location Quality : Good 12 km ( 7 miles) WSW (256 degrees) of Toms Place, CA 19 km ( 12 miles) SE (132 degrees) of Mammoth Lakes, CA 42 km ( 26 miles) WNW (297 degrees) of Bishop, CA 54 km ( 34 miles) SSE (150 degrees) of Lee Vining, CA 62 km ( 38 miles) NW (312 degrees) of Big Pine, CA ADDITIONAL EARTHQUAKE PARAMETERS ________________________________ number of phases : 160 rms misfit : 0.06 seconds horizontal location error : 0.2 km vertical location error : 0.6 km maximum azimuthal gap : 109 degrees distance to nearest station : 6. km In region 2 (098) MT. MORRISON (RSM) event ID: 51058350 ========================================================================== > >_____________________________________________________________________ > >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: Canie Brooks Subject: Re: quake 4 Date: Tue, 14 Jul 1998 23:57:38 -0700 At 11:54 PM 7/14/98 -0700, Stephen & Kathy wrote: >And another one about the same size! >Stephen >Pilot Hill Must be this one: == PRELIMINARY EARTHQUAKE REPORT == Rapid Earthquake Location Service U.S. Geological Survey, Menlo Park, California U.C. Berkeley Seismological Laboratory, Berkeley, California Version 2: Updates lower and earlier versions of this earthquake report This is a computer-generated message -- it has not yet been reviewed by a seismologist. A MINOR EARTHQUAKE OCCURRED AT 11:50 PM PDT Tuesday, Jul 14, 1998. THE MAGNITUDE 3.7 (ML) EVENT IS LOCATED 3 MILES E OF MAMMOTH LAKES, CA THE HYPOCENTRAL DEPTH IS 4.8 MILES. PRINCIPAL EARTHQUAKE PARAMETERS _______________________________ Magnitude : 3.69 ML Event Date & Time : 07/14/1998 11:50:56 PM PDT 07/15/1998 06:50:56 UTC Location : 37.6433 N, 118.9120 W : (37 deg. 38.60 min. N, 118 deg. 54.72 min. W) Depth : 7.8 km. deep ( 4.8 miles) Location Quality : Excellent 5 km ( 3 miles) E ( 96 degrees) of Mammoth Lakes, CA 22 km ( 14 miles) WNW (294 degrees) of Toms Place, CA 40 km ( 25 miles) SSE (152 degrees) of Lee Vining, CA 55 km ( 34 miles) NW (304 degrees) of Bishop, CA 61 km ( 38 miles) E (100 degrees) of Yosemite Village, CA ADDITIONAL EARTHQUAKE PARAMETERS ________________________________ number of phases : 142 rms misfit : 0.09 seconds horizontal location error : 0.3 km vertical location error : 0.4 km maximum azimuthal gap : 42 degrees distance to nearest station : 1. km In region 2 (090) SOUTH MOAT (LVC) event ID: 51058352 ========================================================================== > >_____________________________________________________________________ > >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: Fred S Subject: Re: quake 4 Date: Wed, 15 Jul 1998 17:34:04 -0700 Is it really nessecary to RE-post all the USGS reports. Seems to me anyone on this email list has web access. Just an observation as I compress my mail folder. Fred -- Gravity: It's not just a good idea. It's the LAW ! _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: [Fwd: Re: AFTERSHOCK FORECAST] Date: Wed, 15 Jul 1998 18:52:19 -0600 Dave- The message was not sent to the Public Seismic Network (PSN), but I got my first notification of the Mammoth lakes activity from the 7 messages that PSN members posted within the first couple of hours of the quake, starting with: > Subject: > major quake > Date: > Tue, 14 Jul 1998 21:57:16 -0700 > From: > Stephen & Kathy > Reply-To: > PSN-L Mailing List > To: > PinpointEQ@........... > CC: > psn-l@............. > > > > > Major Quake as I type > Stephen > Pilot Hill Ca USA > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L > and including: > Subject: > Re: second smaller quake > Date: > Tue, 14 Jul 1998 21:39:54 -0700 > From: > Steve Hammond > Reply-To: > PSN-L Mailing List > To: > PSN-L Mailing List > References: > 1 > > > > > Tom's place 5.1 > > http://quake.usgs.gov/recenteqs/Maps/119-38.html > > Regards, Steve Hammond > > Stephen & Kathy wrote: > > > > A second smaller quake is rolling through > > Stephen > > Pilot Hill 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) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L > > Subject: Re: AFTERSHOCK FORECAST > Date: Wed, 15 Jul 98 11:32:54 PDT > From: oppen@................ (David Oppenheimer) > To: bakun@.................... djackson@......... edward_Bortugno@........... > hfmengeo@...................... brune@............... > jdieterich@................... mori@......... > kmcnally@................. jones@....................... > reasen@.................... Rich_Eisner@........... dschwartz@......... > sieh@....................... tcasadev@................... > jdavis@.............. barbara@.................... > lind@.................... pjorgenson@......... dacox@......... > jfilson@......... cnss-list@........ beepers@.................... > warning_center@........... oppen@................... > > The NCSN/BDSN issued its first aftershock probability statement in > response to the M5.1 at Mammoth last evening. The message was issued > ~12 minutes after the mainshock. The message was sent to CA OES for > rebroadcast via their EDIS system to the wire services and was also > posted on the WWW. You can view the latter at the very bottom of the > text page for the mainshock at > > http://quake.wr.usgs.gov/recenteqs/Quakes/nc51058271.html > > So far, there have been no inquiries about the statement to either the > USGS or CA OES. Perhaps the lack of media interest was the routine > occurrence of big events at Mammoth ?? > > -David -- 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". Dave-
    The message was not sent to the Public Seismic Network (PSN), but I got my first notification of the Mammoth lakes activity from the 7 messages that PSN members posted within the first couple of hours of the quake, starting with: 
Subject: 
          major quake
     Date: 
          Tue, 14 Jul 1998 21:57:16 -0700
     From: 
          Stephen & Kathy 
 Reply-To: 
          PSN-L Mailing List 
       To: 
          PinpointEQ@...........
      CC: 
          psn-l@.............




Major Quake as I type
Stephen
Pilot Hill Ca USA

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and including:
  

Subject: 
            Re: second smaller quake
       Date: 
            Tue, 14 Jul 1998 21:39:54 -0700
      From: 
            Steve Hammond 
   Reply-To: 
            PSN-L Mailing List 
        To: 
            PSN-L Mailing List 
 References: 
            1




Tom's place 5.1 

http://quake.usgs.gov/recenteqs/Maps/119-38.html

Regards, Steve Hammond

Stephen & Kathy wrote:
> 
> A second smaller quake is rolling through
> Stephen
> Pilot Hill Ca
> 
> _____________________________________________________________________
> 
> Public Seismic Network Mailing List (PSN-L)
> 
> To leave this list email listserver@............. with the body of the
> message: leave PSN-L

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Subject: Re: AFTERSHOCK FORECAST

Date: Wed, 15 Jul 98 11:32:54 PDT

From: oppen@................ (David Oppenheimer)

To: bakun@.................... djackson@......... edward_Bortugno@...........

     hfmengeo@...................... brune@...............

     jdieterich@................... mori@.........

     kmcnally@................. jones@.......................

     reasen@.................... Rich_Eisner@...........
dschwartz@.........

     sieh@....................... tcasadev@...................

     jdavis@.............. barbara@....................

     lind@.................... pjorgenson@.........
dacox@.........

     jfilson@......... cnss-list@........ beepers@....................

     warning_center@........... oppen@...................


The NCSN/BDSN issued its first aftershock probability statement in

response to the M5.1 at Mammoth last evening.  The message was
issued

~12 minutes after the mainshock.  The message was sent to CA OES
for

rebroadcast via their EDIS system to the wire services and was also

posted on the WWW.  You can view the latter at the very bottom
of the

text page for the mainshock at


http://quake.wr.usgs.gov/recenteqs/Quakes/nc51058271.htm
l


So far, there have been no inquiries about the statement to either the

USGS or CA OES.  Perhaps the lack of media interest was the routine

occurrence of big events at Mammoth ??


-David

 

--

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: Arie Verveer 
Subject: Re: Kermadec Lr-Lq Attenuation
Date: Thu, 16 Jul 1998 01:26:00 +0800

Hi Meredith,


> Am questioning the Kermadec Islands 6.3 quake of 7/9/98, which
> occurred at 14:45:26.  Why do all the records from many amateur
> sources have such large P & S traces, and the LR-LQ traces have
> such low amplitudes?

In my case I'm using a high and low frequency output from theseismometer
electronics.  I generally post the high frequency
output "AU1" + "AU3" and rarely post the low frequency "AU2"
and"AU4".  The low frequency gives a nice display on the LR-LQ
waves. Maybe I should post both on a big event?

Regards

Arie




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From: EARTHQUAKE REPORTING 
Subject: Re: [Fwd: Re: AFTERSHOCK FORECAST]
Date: Wed, 15 Jul 1998 18:46:28 -0700

At 06:52 PM 7/15/01 -0600, Edward Cranswick wrote:
>Dave-
>    The message was not sent to the Public Seismic Network (PSN), but I
got my
>first notification of the Mammoth lakes activity from the 7 messages that PSN
>members posted within the first couple of hours of the quake, starting with:

Ed etal;
The problem is net-wide and concerns both DNS lookups as well as a buried
COBAL error that has been lurking. This problem is causing multiple sends
amongst other major problems. I addressed this problem to CERN 6 weeks ago
but received no response.....BTW..It is my impression as a long time (34
years) programmer that this is another in a series of problems that will
come as a hidden scenario in this Y2K stupidity.....sort of a nested
problem but we have so many "experts" out there that nobody wants to listen
to simple logic!
Bob Shannon
Pinpoint Since 2001:->


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From: 
Subject: Re:  {EarthWaves} Re: quake  4
Date: Wed, 15 Jul 1998 22:39:18 EDT

Uh.... Fred?

We got the message -- three times. Looks like your server is hiccuping again.

:) 

Adrienne

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From: meredith lamb 
Subject: SG Electronics
Date: Wed, 15 Jul 1998 21:32:53 -0600

Hi Arie,

I'd be interested in seeing your low frequency event files
for the bigger events.  Am amazed by what I've seen in the past
for the SG response.  Your seismo is the smallest I've seen,
but it sure seems to work well for near and far quakes.

Guess I have more of a long period seismo interest. 

Do have a question.....is your electronics basically the same as
per the PSN schematic, or...is it different, or is it Larry Cochranes
commercial amplifier model?

Thanks, Meredith Lamb


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From: Karl Cunningham 
Subject: Tiltmeter Concept
Date: Thu, 16 Jul 1998 08:45:15 -0700

Greetings --

An item crossed my desk at work that has been patented (Pat no 5,632,093),
that is a tiltmeter design I hadn't seen before.  It contains an
arrangement of coils similar to that of an LVDT, but instead of having a
moving core it is partially submerged in a ferromagnetic fluid.  This fluid
provides the magnetic coupling from primary to the secondaries.  As the
apparatus is tilted (or accelerated), the fluid covers more of one
secondary and less of the other, and causes an imbalance in the output of
the pickup coils.

Cute idea.  Just thought some of you might be interested.




Karl Cunningham
La Mesa, CA.
PSN station #40
karlc@.......

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From: Doug Crice 
Subject: Re: quake  4
Date: Thu, 16 Jul 1998 09:51:07 -0700

I rather appreciate the re-posting of the USGS reports.  It's an easy
way to get the magnitude and location, which doesn't usually come
through the usual messages.  Sure, I could look it up, but I wouldn't.
-- 
Doug Crice          web site http://www.georadar.com
GeoRadar Inc.             e-mail dcrice@............
19623 Via Escuela Drive           phone 408-867-3792
Saratoga, CA 95070 USA              fax 408-867-4900


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From: Karl Cunningham 
Subject: Re: quake  4
Date: Thu, 16 Jul 1998 13:17:30 -0700

I subscribe to the Quake-L email list from LISTSERV.NODAK.EDU.  Although it
is not limited to USGS reports, there is so little other traffic it might
as well be.

I offer this as a suggestion that might satisfy some people -- one could
get the reports automatically yet not have them come through this list.


Karl Cunningham
La Mesa, CA.
PSN station #40
karlc@.......

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From: Robert Avakian 
Subject: Re: quake  4
Date: Thu, 16 Jul 1998 15:56:53 -0700

How do we subscribe to the service?  

Bob Avakian

Karl Cunningham wrote:
> 
> I subscribe to the Quake-L email list from LISTSERV.NODAK.EDU.  Although it
> is not limited to USGS reports, there is so little other traffic it might
> as well be.
> 
> I offer this as a suggestion that might satisfy some people -- one could
> get the reports automatically yet not have them come through this list.
> 
> 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


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From: "Francesco" 
Subject: ADRIATIC SEA   e SANTA CRUZ
Date: Thu, 16 Jul 1998 23:55:57 +0200

h 17.29   UTC
MB 4.4
Located: Central Adriatic Sea  - Greece-Albania border region

----------------------------

All italian station had registered at 14.16 Utc  Santa Cruz Island quake =
 Ms 6.6
Good S  and large LQ -  LR


Francesco Nucera
I.E.S.N.  - PSN ITALY









h 17.29   UTC


MB 4.4


Located: Central Adriatic Sea  =
-=20
Greece-Albania border region


 


----------------------------


 


All italian station had registered =
at 14.16=20
Utc  Santa Cruz Island quake  Ms 6.6


Good S  and large LQ - =20
LR


 


 


Francesco Nucera


I.E.S.N.  - PSN=20
ITALY


From: Arie Verveer 
Subject: Re: SG Electronics
Date: Fri, 17 Jul 1998 03:15:17 +0800

Hi Meredith

> I'd be interested in seeing your low frequency event files
> for the bigger events.

What luck,  the " Ms6.6 Santa Cruz Islands " is a good exampleof the low
frequency response of the seismometer. I've
just posted the event to the PSN event list.
{High frequency "AU3" ,  Low frequency "AU4"}
I haven't post filtered the data but did cut the samples down to
10 per second to save space in posting.


> Do have a question.....is your electronics basically the same as
> per the PSN schematic, or...is it different, or is it Larry Cochranes
> commercial amplifier model?
>

Its Larry's commercial amplifier. The only thing that I havechanged is the
low frequency response for the N-S seismometer.
It was made to respond to slightly higher frequency's and thus
give a reasonable "P" and "S" wave from the events that come
from the Java trench area. I left the E-W alone.
The amplifier works very well.


All the best


Arie.



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From: meredith lamb 
Subject: SG Electronics
Date: Thu, 16 Jul 1998 22:36:19 -0600

Hi Arie,

Thanks for the fast service on the Santa Cruz quake and your
low frequency seismogram response-ha.  Luck yes!

Interesting.  I put one gram behind the other up against a lamp,
and except (generally) for the short period waves amplitude,
theres not a great deal of difference overall.

Obviously, the amplifier does indeed work well.

Two more questions.  Whats the weight of your S-G mass?
Whats your hinge material, thickness, width, and distance
between hinges?  For comparison to the original on the PSN site.

...........

>From all the PSN seismograms I've seen of the Santa Cruz
Islands quake, it appears like the travel times for deeper quakes
and phases like, Lq-Lr, is obviously shorter than standard surface
quakes, as none seem to really match up as marked for their
apparent respective phases...including mine of course-ha.

Thanks, Meredith Lamb





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From: "David A. Nelson" 
Subject: ANOTHER large west Pacific event 
Date: Fri, 17 Jul 1998 21:42:42 +1200


  09:30 UTC  17 July     another large west pacific event in progress

 surface waves  now dying off for me and  tony in hawaii


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


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From: "Francesco" 
Subject: LARGE EVENT
Date: Fri, 17 Jul 1998 12:56:39 +0200

LARGE SURFACE WAVE
08.50 UTC
NEW GUINEA?

FRANCESCO NUCERA
I.E.S.N. PSN ITALY









LARGE SURFACE WAVE


08.50 UTC


NEW GUINEA?


 


FRANCESCO=20
NUCERA


I.E.S.N. PSN ITALY


From: barry lotz 
Subject: Re: ANOTHER large west Pacific event
Date: Fri, 17 Jul 1998 04:47:29 -0700

Hi
 Picked it up here in California also.
                             Barry


>David A. Nelson wrote:
> 
>   09:30 UTC  17 July     another large west pacific event in progress
> 
>  surface waves  now dying off for me and  tony in hawaii
> 
> Dave
>

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From: Karl Cunningham 
Subject: Re: quake  4
Date: Fri, 17 Jul 1998 10:50:34 -0700

Bob --

Here are the instructions for the QUAKE-L list:

The QUAKE-L list is for general discussions about earthquakes. The list
covers a wide range of topics from discussions of specific earthquakes and
the after-effects to various theories and scientific principles of
earthquakes and related phenomena. QUAKE-L is now on
listserv@.................. (host site is the North Dakota Higher Education
Computer Network).

To subscribe to the list send e-mail to listserv@.................. with
the command:

sub quake-l [your_first_name your_last_name]
For example: sub quake-l James Witt
You will be asked to confirm your subscription and will then be sent
further information about workings of the LISTSERV server. The QUAKE-L
owner/manager is Marty Hoag, hoag@................. 

Karl Cunningham
La Mesa, CA.
PSN station #40
karlc@.......


At 03:56 PM 7/16/98 -0700, you wrote:
>How do we subscribe to the service?  
>
>Bob Avakian
>


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From: barry lotz 
Subject: Santa Cruz vs Papua NG
Date: Fri, 17 Jul 1998 18:10:07 -0700

Dave 
   The pervious discussion about surface waves and event depth is
displayed in the difference between these two events. One at around 33k
with large surface wave component and the other at 110k w/o much surface
wave component. Both are in the same general area . Good call.
                                       Barry

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From: Arie Verveer 
Subject: Re: SG Electronics
Date: Sat, 18 Jul 1998 20:08:23 +0800

Hi Meredith,

> Two more questions.  Whats the weight of your S-G mass?
> Whats your hinge material, thickness, width, and distance
> between hinges?  For comparison to the original on the PSN site.
>

The Pendulum weighs around 70 grams. The hinge is made up oftwo separate brass hinges some
0.002" in thickens by 8 millimetres
wide and 5 mm between the hinges. The hinges are separated by
28 mm between centres. The pendulum has a natural frequency
around  1 Hertz.

Image at:

http://www.iinet.net.au/~ajbv/SG/Penbulum/Pendulum.htm

I should include these numbers in the web page. I'll put
it on the list of things to do.

All the best.

Arie.




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From: "Margarida Conde" 
Subject: SDR questions
Date: Sat, 18 Jul 1998 15:38:26 +0100

Two questions about SDR:
1) How to keep the SDR time accurate?
In the documentation I´ve found references to a short wave radio receiver.
Are there any alternatives? For instance, can I keep my PC clock accurate by
the network?
Which DOS software should I use? Can SDR do that alone?
2) Where to get the latest version of SDR? I believe that the one at
http://psn.quake.net is not the latest one. Am I wrong?
TIA
Margarida Conde
mconde@...............



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From: bob ogburn 
Subject: Re: SDR questions
Date: Sat, 18 Jul 1998 09:10:57 -0700

In response to Q1:
The method used here is to synchronize the local clock using the SNTP (pr=
otocol)
as described in RFC 1796.
It is important to select a time server that has the most consistent path=
 as
determined by using trace route.
This technique is not automatic, you must periodically run a time synch t=
o
correct your local clock.
In Windows, I use the time sync routine in a program called NetScanTools
(shareware from Kirk Thomas), a very useful suite.
To obtain a DOS compatible program, search for SNTP at the shareware site=
s.

An alternative, real-time method would be to recover the UTC information =
from a
GPS receiver and record it using your data collection routine.

bob ogburn PSN Daly City California E-W SG

Margarida Conde wrote:

> Two questions about SDR:
> 1) How to keep the SDR time accurate?
> In the documentation I=B4ve found references to a short wave radio rece=
iver.
> Are there any alternatives? For instance, can I keep my PC clock accura=
te by
> the network?
> Which DOS software should I use? Can SDR do that alone?
> 2) Where to get the latest version of SDR? I believe that the one at
> http://psn.quake.net is not the latest one. Am I wrong?
> TIA
> Margarida Conde
> mconde@...............
>
> _____________________________________________________________________
>
> Public Seismic Network Mailing List (PSN-L)
>
> To leave this list email listserver@............. with the body of the
> message: leave PSN-L




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From: "David A. Nelson" 
Subject: 3RD BIG SW Pacific quake
Date: Sun, 19 Jul 1998 08:30:02 +1200

hi all
           the 3rd big quake in this pa4rt of the world in as many days

  Ms6.0  in the Vanuatu Islands


 BTW  the Mw7.1  from the nth coast of  PNG  caused a 7 metre   (~22ft)
tsunami  drowning at least 70 ppl  as it wiped out coastal villages in this
VERY remote part of the country.

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


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From: Larry Cochrane 
Subject: Re: SDR questions
Date: Sun, 19 Jul 1998 15:21:30 -0700

Hi Margarida,

At 03:38 PM 7/18/98 +0100, you wrote:
>Two questions about SDR:
>1) How to keep the SDR time accurate?
>In the documentation I´ve found references to a short wave radio receiver.
>Are there any alternatives? For instance, can I keep my PC clock accurate by
>the network?
>Which DOS software should I use? Can SDR do that alone?

Here in the lower United States (from what I hear WWV does not work very
well in Alaska, and Hawaii has WWVH so it should work very well there) SDR
users can use WWV, or WWVB with the new release of SDR coming out soon. It
can also use the serial port that is connected up to another system that
can send out accurate time. The serial port can be use to daisy chain
several SDR systems together, if you need more than 6 channels, or it can
be connected up to a system that is using NTP (Network Time Protocol) or
some other means to keep its clock accurate. SDR then checks the time on
the other system every 15 minutes and uses this info for its internal time
keeping.  

NTP should work fine if the time server system is connected up to a high
speed link into the Internet. With a 28k modem there can be several 100ths
of milliseconds latency, so the time jumps around a lot.

I think the way to go for people who can not receive WWV/WWVB or don't want
to setup another system to act as time server, is to use GPS. One of the
main drawbacks too using GPS is cost. Too get a GPS receiver with accurate
time output, one needs a special unit. The off the shelf GPS receivers are
not designed with accurate timing output in mind. If someone knows of a
commercial unit that does have good time (< 10Ms) output please let me /
the group know. 

I am working with Ray (sorry I don't know Ray's last name) at
rayv@............................ He has purchased a unit that has the 1
pulse per second output need for accurate time keeping. He will be sending
the unit to me this week so I can add the code need to use it with SDR.
Maybe Ray can tell us more about the cost and where he got it. I believe
the cost is around $250.00. The receiver costs around 180.00 but you still
need an antenna, box and power supply etc.

One more thing about SDR. SDR does not use the computers time except when
it first start up. After reading the systems time at startup of the
program, SDR keeps track of the time by using the 1 ms interrupt generated
by the A/D card. This is why running TSRs like RIGHTTIME does not help. In
fact, they can cause problems by disabling interrupts too long and causing
SDR to miss interrupts.

>2) Where to get the latest version of SDR? I believe that the one at
>http://psn.quake.net is not the latest one. Am I wrong?
>TIA

The version I have on my site is very old. I am shipping version 2.2 with
my A/D card and I have the next release almost ready. I want to add the GPS
code before I release the next version.  I will send Margarida, and anyone
else who would like to have it, the current release and the current beta
release.

Regards,
Larry Cochrane
Redwood City, PSN




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From: Greg 
Subject: Re: SDR questions
Date: Sun, 19 Jul 1998 16:12:41 -0700

Larry Cochrane wrote:

> If someone knows of a
> commercial unit that does have good time (< 10Ms) output please let me =
/
> the group know.

I metioned this before. I don't think it went to the list though.
http://www.tapr.org/ has lots of GPS and timing stuff. However it's all
in a kit form. The recievers are probably like Ray's with the seperate
antenna. They have some software TAC-32 (Totally Accurate Clock) that
shows the time and the number of satellites and signal strength and
stuff, but I don't think it acts as a time server. It does adjust the
hardware clock though. If there was a Windows 95 based network time
server, it would be pretty good. I don't know of any.

From the web page:
"The software can automatically reset the PC=EDs internal clock with 25
msec accuracy."
It's not 10ms but I doubt WWV is either.

TAPR (Tucson Amateur Packet Radio) is a ham club of sorts, but I doubt
you'd need a license to buy the recievers. There is a discount to
members, of which I am not. Which is not unreasonable since I am now a
ham in Tucson. The club is somewhat nationally (at least) known.

I did a lot of searching for commercial time servers and WWV recievers
and everything I found was too expensive to even look at. For me at
least. I did see some equipment under $3,000. I think that this would be
a decent place for a Linux time server with a GPS receiver plugged into
the serial port and a network card in it. Of course that means 2
computers running 24 hours. If one computer could handle the GPS and the
SDR, that would be ideal.

Sorry about the short choppy sentences,
Greg

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From: Steve Hammond 
Subject: Re: SDR questions
Date: Sun, 19 Jul 1998 20:09:27 -0700

Larry Cochrane wrote:
>=20
> Hi Margarida,
>=20
> At 03:38 PM 7/18/98 +0100, you wrote:
> >Two questions about SDR:
> >1) How to keep the SDR time accurate?
> >In the documentation I=B4ve found references to a short wave radio rec=
eiver.


Here is a WWV clock for $99.95 with a serial interface. I was thinking
about getting this and giving it a try. It keeps time if WWV is lost.=20
http://www.feist.com/~bodegroup/arc5.html=20

Regards, steve Hammond PSN San Jose

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From: Bob Fryer 
Subject: Quake sensitives on PBS
Date: Mon, 20 Jul 1998 18:21:57 -0700

Hello folks,

Saw "Savage Earth" part 1 and 2 last night on PBS, and it was well done.

Tonight's episodes, parts 3 and 4, should have some of my earthquake
sensitive friends.  Ali Rhoden of SoCal, who was interviewed for the show,
is one of the more sensitive of them.  I have spent several weeks with her
family.

Am really curious to see how they treat the subject.  Many of us were
interviewed or taped for another show that will air in Britain in
September, here later, on Discovery Channel.

Also, enjoyed the too brief meeting with Larry Cochrane at the IRIS seminar.

Take care,
Bob Fryer


----- earthquake WARNING research -----
--- animals, people, scientific evidence ---
---  http://www.teleport.com/~bfryer ---



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From: "Rex Klopfenstein, Jr." 
Subject: PSN-SDR Board & PC Power Saving Functions
Date: Mon, 20 Jul 1998 21:27:37 -0400

I have just upgraded an old 386 minitower to a 166MHz Pent.  I bought
the mother board and CPU for about $170 (since the Pent II came out, the
Pent equipment has really dropped in price!!).  I have my SDR board in
it running WIN98 without any problems.

These new boards have provisions to power down the monitor and spin down
the hard drive.  This would be nice for a machine that sets there doing
nothing but watching incoming signals for most of the time.

My questions to the low level system wizards are as follows:

Will the SDR software let the monitor and disk drive shut down or will
it see activity that keeps the equipment active?

Will I lose any data if I let the system shutdown the disk drive?  My
gut feeling is it shouldn't because there should be enough buffer to
queue data until disk gets up and running.

Thanks in advance

Rex Klopfenstein, Jr
Bowling Green, OH


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From: Pinpoint 
Subject: Re: Quake sensitives on PBS
Date: Mon, 20 Jul 1998 18:31:00 -0700

At 06:21 PM 7/20/98 -0700, Bob Fryer wrote:
>Hello folks,
>
>Saw "Savage Earth" part 1 and 2 last night on PBS, and it was well done.

It is still on here in the PNW at 49 degrees but obvious that Ali and
Kathys parts are over... A number of things struck me...

 #1 It must have cost a lot of money to do a show like this...lots and
lots...Ali spent much time worrying and thinking about he taping crew which
came in, but only had a few seconds on a big long show...Of course that
part of timing is understood, but imagine the amount of money that must
have gone into this production. I think the show as a whole was very
dynamic and VERY VERY Good!

  #2...To You Kathy F. You must have been a looker cus you still ARE!:->
And I say that with all honesty. What an honest, youthfull and enjoyable
few seconds I had seeing you! I am so glad your feeling a bit better!

    Now having said that Ali----Of course you and Larry were too cool....as
were the pics of the Punchbowl....I fell so very priviledged to know you
both! And thank you also for your support and help over the years! What a
great show!

>Also, enjoyed the too brief meeting with Larry Cochrane at the IRIS seminar.

Add to that Bob F. that you might have seen Steve Malone the author of the
software for Iris..Did you get to see him? I have only talked with him via
email and once in a great while.........What a group! I am now totally
impressed!
Again!
Bob

 
>Take care,
>Bob Fryer
>
>
>----- earthquake WARNING research -----
>--- animals, people, scientific evidence ---
>---  http://www.teleport.com/~bfryer ---
>
>
>
>_____________________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email listserver@............. with the body of the 
>message: leave PSN-L
>
>

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From: Larry Cochrane 
Subject: IRIS workshop earlier this month
Date: Mon, 20 Jul 1998 23:42:42 -0700

Hi Everyone,

Sorry for not writing about this sooner. The last few weeks have been very
hectic...

The workshop entitled "Teaching Seismology Using Education Software" went
very well. I presented WinQuake and also talked about the PSN and our web
sites. There where 10 presentations, and about 20 other people, each
lasting about 30 minutes. The first few presentations where Web based
teaching tools and information / data sites.

Bob Woodward, from Albuquerque Seismological Laboratory, talked about their
LISS service. LISS stands for Live Internet Seismic Server. What they have
done is place some, currently 29 of the 115, broadband seismic stations on
the Internet. The data from these stations are sent to Albuquerque using
the Internet and then re broadcasted, again using the Internet, to anyone
who wants the data in near real time. There is about 30 to 60 seconds of
latency from the time the sensor records the data and to when you get it.
More info about LISS can be found at
http://aslwww.cr.usgs.gov/Seismic_Data/liss.htm.

After the web based talks there was only one person who present a Mac based
software package. All of the rest where PC based. The Mac based program is
called Wiggles. It is similar to WinQuake in that it is used to analyze
event files. It can read / write SAC binary files.

One program called DIMAS was interesting. Bob Woodward also presented this
one.  DIMAS is used to analyze seismograms. They pass it out to their
remote station operators so they can look at the data produced by the
seismometer and do some simple analyses. This program can try and locate
the event using one three component station. The azimuth is determined by
the partial motion based on the P wave and the distance using the P and S
wave. Since the azimuth and distance are known, the approximate location
can be determined. It can also locate the event based on multiple station P
and S wave distances. It also has the ability to display the information on
a map. What's nice about DIMAS is they supply the source code, in "C"!!!

I have already added two new features to WinQuake. One uses the travel time
table used by DIMAS. The file is similar to the JB travel time tables
currently used by WinQuake, but contain more phases and all of the data is
located in one 2 Meg file (it zips down to around 400K). It seems to be
only useful for teleseismic events. The regional JB travel time tables seem
to work better for local events, so I will not be removing the JB table
support. The other thing I am playing around with is the mapping feature. I
currently have WinQuake displaying a map with the stations and distance
circles based on the event file windows and the placement of the P and S
markers in each window. What I need to do before I get too far into this is
to make sure that I can use the data and code from their program. I hope to
add other features from DIMAS if I get permission and as I can find time to
do it.

Michelle HallWallace, she hosted the event, has created a web page at
http://www.geo.arizona.edu/K-12/azpepp/education/software/IRIS.software.html
.. The page has links to all of the information presented at the workshop.
This page may move to somewhere under www.iris.edu at some point.

One thing that was a little strange, and several people pointed this out,
was the no one from PEPP (Princeton Earth Physics Project) was there. Since
their organization is based on placing seismometers in high schools, one
would think they would have someone there showing their software and
learning about what others are doing. Several people came up to me and ask
if we (PSN) are doing anything with PEPP. I had to say very little. I
explained that several of their members are using WinQuake and that John
Taber, from the Victoria University of Wellington in New Zealand, is using
some of the PSN hardware/software and incorporating the course work from
the PEPP.

Regards,
Larry Cochrane
Redwood City, PSN
  




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From: "William Combs" 
Subject: RE: IRIS workshop earlier this month
Date: Tue, 21 Jul 1998 13:41:00 -0500



Larry,

I do not know what happened to PEPP but I heard a hacker got into their
server and I have not been able to upload files since. Here in central
Indiana I have been able to pick up most M6.0 quakes on their seismograph.
M5.5 or greater out of Central America. I hopefully will get a webpage up on
the school server this fall.

One thing that was a little strange, and several people pointed this out,
was the no one from PEPP (Princeton Earth Physics Project) was there. Since
their organization is based on placing seismometers in high schools, one
would think they would have someone there showing their software and
learning about what others are doing. Several people came up to me and ask
if we (PSN) are doing anything with PEPP. I had to say very little. I
explained that several of their members are using WinQuake and that John
Taber, from the Victoria University of Wellington in New Zealand, is using
some of the PSN hardware/software and incorporating the course work from
the PEPP.

Regards,
Larry Cochrane
Redwood City, PSN





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From: S-T Morrissey 
Subject: STM seis at IRIS workshop
Date: Tue, 21 Jul 1998 14:08:10 -0500 (CDT)

Re. IRIS workshop at Santa Cruz

To answer some queries about the presentations at the IRIS workshop
at Santa Cruz July 8 to 11. I unfortunately did not meet Larry C,
since his seminar was Wednesday morning and I finally found the 
right location about 5 PM (the maps were really cryptic) where the 
posters were to be set up. I was asked to present a working STM seis
as well as one to have hands-on contact. Of course the working seis
had limited stability on a table top, but everyone got the idea.
The presentations were up for all three days, and interest in the
seis led others to help with the explanations while I attended
other formal presentations of the workshop.

The poster portion was the calibration and noise data from the March
presentation at the SSA (Seismological Society of America) meeting 
in Boulder; nothing new, but the comparisons of the STM data
with regional commercial VBB sensors (the Streckeisen STS-1) had
many asking why they were paying around $15k for the STS-1. Many
wanted to sign up for a "production" copy of the sensor, or at least
for the electronics box.  I had used the Validyne electronics for the 
VRDT displacement transducer and a completely "passive" feedback
(no amplifiers and a R-C-R integrator) for the demo, which greatly 
reduced the high frequency response as expected, but made the 
feedback seem quite simple for a response that was flat from 1 hz
to 50 seconds or so.

The most consistent concerns were about the physical size, which
complicates the pressure containment of the vertical, and the 
thermal response, which needs some serious study. The size can be
reduced if the boom is shortened, which requires a lot more clearance
of the coil within the magnet (of the 10" speaker). THis brings
up the options of modifying the magnet gap (with a machine lathe)
or winding a coil less than about 0.5mm thick.  The thermal response
of the leaf spring may need some active compensation.

The few copies of the current mechanical drawing of the seis 
disappeared; I will hopefully scan it and post it on the web 
later this week.

I had hoped to see more of the PEPP (Princeton Earth Physics Project)
program, but there was not much presented. There was a poster 
about adding a capacitive displacement sensor to a 4.5hz geophone, 
requiring complicated machining. I have recently successfully
added a VRDT to a 4.5 hz phone in a much simpler fashion, but have
not implemented it with a VBB response ... yet. (Such a VBB sensor
will have an inherently high noise level because the mass is only
22 grams.)

Regards,
Sean-Thomas.

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From: Larry Cochrane 
Subject: Re: PSN-SDR Board & PC Power Saving Functions
Date: Tue, 21 Jul 1998 23:02:21 -0700

At 09:27 PM 7/20/98 -0400, Rex Klopfenstein, Jr wrote:
>I have just upgraded an old 386 minitower to a 166MHz Pent.  I bought
>the mother board and CPU for about $170 (since the Pent II came out, the
>Pent equipment has really dropped in price!!).  I have my SDR board in
>it running WIN98 without any problems.

SDR will have problems with time keeping if it is run inside of a DOS box.
Does Win98 have a DOS only mode similar to Win95?

>
>These new boards have provisions to power down the monitor and spin down
>the hard drive.  This would be nice for a machine that sets there doing
>nothing but watching incoming signals for most of the time.

I recommend that all of the motherboard Green power monitoring stuff be
disabled. I ran into problems with SDR dropping interrupts do to the
interrupt monitoring done by the power monitoring. Also, SDR is not just
sitting there waiting for an event. It is constantly saving all of the data
it records too disk. This gives it the ability to replay the data to see
what you got at a particular time and not rely only on triggered data.

>
>My questions to the low level system wizards are as follows:
>
>Will the SDR software let the monitor and disk drive shut down or will
>it see activity that keeps the equipment active?

Since SDR is saving data too disk every minute, you don't want to start and
stop the motor that often. I really don't think the few cents, if that,
saved each month is worth the trouble. Starting and stopping a motor
constantly will cut down on the life of the drive. The few cents save would
be lost if you need to buy a new drive. With portable computers it make
more sense to save every watt....

The monitor is another story. It uses a lot more power than a motor and
turning it on and off makes more sense.

>
>Will I lose any data if I let the system shutdown the disk drive?  My
>gut feeling is it shouldn't because there should be enough buffer to
>queue data until disk gets up and running.

Again, SDR uses the disk drive too often to turn it on and off.

-Larry Cochrane
Redwood City, PSN


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From: Fred S 
Subject: Re: PSN-SDR Board & PC Power Saving Functions
Date: Tue, 21 Jul 1998 23:09:01 -0700

Win 98 Power save functions may have some bugs.  My system and 2 other's
at my company all lock up periodicly when the monitor powers down. 

Just a warning

Fred
-- 
Gravity:  It's not just a good idea.  It's the LAW !

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From: Larry Cochrane 
Subject: Re: PSN-SDR Board & PC Power Saving Functions
Date: Tue, 21 Jul 1998 23:32:58 -0700

A bug in Win98??? Unbelievable...

-Larry

At 11:09 PM 7/21/98 -0700, Fred S wrote:
>Win 98 Power save functions may have some bugs.  My system and 2 other's
>at my company all lock up periodicly when the monitor powers down. 
>
>Just a warning
>
>Fred
>-- 
>Gravity:  It's not just a good idea.  It's the LAW !
>
>_____________________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email listserver@............. with the body of the 
>message: leave PSN-L
>

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From: Jim Hannon 
Subject: Re: PSN-SDR Board & PC Power Saving Functions
Date: Wed, 22 Jul 1998 06:11:35 -0500

Larry Cochrane wrote:
> 
> 
> SDR will have problems with time keeping if it is run inside of a DOS box.
> Does Win98 have a DOS only mode similar to Win95?
> 
Win98 has the same DOS only mode as Win95. In fact overall Win98 is so
similar to Win95 that I question calling it a new OS :)


-- 
Jim Hannon
http://soli.inav.net/~jmhannon/
42,11.90N 91,39.26W
WB0TXL


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From: watson@................ (Charles Watson)
Subject: Re: IRIS workshop earlier this month
Date: Wed, 22 Jul 1998 07:51:25 -0700

Thanks for the IRIS report. A lot of useful stuff. Could you send me a 
contact for the Mac based Wiggles program?

-- 
---/----
Charles P. Watson
Seismo-Watch

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From: watson@................ (Charles Watson)
Subject: Larry, I found it..
Date: Wed, 22 Jul 1998 07:54:22 -0700

Larry, I found more info about the Wiggles program at Michelle 
HallWallace's web page. 

Thanks again for your report!

-- 
---/----
Charles P. Watson
Seismo-Watch

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From: meredith lamb 
Subject: Re: STM seis at IRIS workshop & Magnet reworking concern
Date: Wed, 22 Jul 1998 14:16:54 -0600

Sean-Thomas,

With your message it sounds like the STM-8 was a big success,
and drew alot of interest at the IRIS workshop.  Congratulations!

In regards to reworking the magnet (as is) on a machine lathe, it
might ruin the ferrite on clamping of the lathe head, as its pretty
fragile stuff.  The chips from any successful cutting will also be a
problem of removal.  Even if the center pole washer edge is
clamped and cutting commences, the ferrite may still shatter from
the cutting pressure on the upper washer.  The steel is tough stuff.

Had the bad experience of trying drilling a hole on the center pole
side, tapping, and using a 1/4-20 bolt to force the washers apart,
with the idea of washers/ferrite separation.  Turns out the ferrite
is securely glued to the washers, and the glue held, but the ferrite
didn't....ugh!  The width of the ferrite from the outer edge to the
inner ID edge is .950".  I also misjudged the width of the magnet
and promptly learned that ferrite readily dulls drills..from that,
it would appear that trying to rework ferrite alone is a tough task.

Aside from the cost of machining and the risk of the voice coil
magnet destruction, offhand, it would not appear to be the better
choice of approach.  The choices would seem to be...

1.  Leave it as is.
2.  Find another commercial speaker thats workable.
3.  Homebrew a speaker magnet assembly and/or borrow a
    coil from a commercial speaker,etc, or make your own coil.

FB magnets/coils rule...seismometrists drool-ha.  Ahem....

Anyway...will be looking forward to your new mechanical drawing.

Meredith Lamb


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From: "Rex Klopfenstein, Jr." 
Subject: Re: PSN-SDR Board & PC Power Saving Functions
Date: Wed, 22 Jul 1998 17:54:41 -0400



Larry Cochrane wrote:

> >SDR will have problems with time keeping if it is run inside of a DOS box.
> >Does Win98 have a DOS only mode similar to Win95?
>

Yes, from what I understand WIN98 is better described as a service release than
new program.  When I load SDR I generated a DOS shortcut and there is a DOS box
in WIN98.


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From: barry lotz 
Subject: Re: STM seis at IRIS workshop & Magnet reworking concern
Date: Wed, 22 Jul 1998 16:37:35 -0700

Hi
 I bought two ceramic grade 5 ring magnets from an outfit in Calif a few
years ago. The Dowling Miner Magnets corp.(1-800-magnet-1) 707-935-0352.
they were 4.33" OD and 1.77" ID  0.425" thick and cost around $10 ea.
They had a pretty good selection of ring magnets.
                                           Barry

meredith lamb wrote:
> ....
> In regards to reworking the magnet (as is) on a machine lathe, it
> might ruin the ferrite on clamping of the lathe head, as its pretty
> fragile stuff.  The chips from any successful cutting will also be a
> problem of removal.  Even if the center pole washer edge is
> clamped and cutting commences, the ferrite may still shatter from
> the cutting pressure on the upper washer.  The steel is tough stuff.
> 
> Had the bad experience of trying drilling a hole on the center pole
> side, tapping, and using a 1/4-20 bolt to force the washers apart,
> with the idea of washers/ferrite separation.  Turns out the ferrite
> is securely glued to the washers, and the glue held, but the ferrite
> didn't....ugh!  The width of the ferrite from the outer edge to the
> inner ID edge is .950".  I also misjudged the width of the magnet
> and promptly learned that ferrite readily dulls drills..from that,
> it would appear that trying to rework ferrite alone is a tough task.
> 
> Aside from the cost of machining and the risk of the voice coil
> magnet destruction, offhand, it would not appear to be the better
> choice of approach.  The choices would seem to be...
> 
> 1.  Leave it as is.
> 2.  Find another commercial speaker thats workable.
> 3.  Homebrew a speaker magnet assembly and/or borrow a
>     coil from a commercial speaker,etc, or make your own coil.
>

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From: barry lotz 
Subject: Owens Valley
Date: Wed, 22 Jul 1998 19:20:19 -0700

I was listening to NPR with regards to the restoring water to the
Owens Valley. That area has been awfully quiet since the 1872 event. Has
anyone heard about the potential affect of the restoring water to the
valley and it's affect on potential earthquakes? 
                                  Barry

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From: Greg 
Subject: Re: Owens Valley
Date: Wed, 22 Jul 1998 20:27:44 -0700

barry lotz wrote:

> anyone heard about the potential affect of the restoring water to the
> valley and it's affect on potential earthquakes?

In Tucson, Arizona the city is supposedly "recharging the water supply"
with water routed from somewhere else? I'm somewhat new here and I don't
know all of the facts, but no earthquakes yet ;) I doubt the water is
being forced in under any pressure like the Denver deal.

,Greg

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From: Jim Hannon 
Subject: Re: STM seis at IRIS workshop & Magnet reworking concern
Date: Wed, 22 Jul 1998 22:44:06 -0500

meredith lamb wrote:
> 
> In regards to reworking the magnet (as is) on a machine lathe, it
> might ruin the ferrite on clamping of the lathe head, as its pretty
> fragile stuff.  The chips from any successful cutting will also be a
> problem of removal.  Even if the center pole washer edge is
> clamped and cutting commences, the ferrite may still shatter from
> the cutting pressure on the upper washer.  The steel is tough stuff.
> 
> Had the bad experience of trying drilling a hole on the center pole
> side, tapping, and using a 1/4-20 bolt to force the washers apart,
> with the idea of washers/ferrite separation.  Turns out the ferrite
> is securely glued to the washers, and the glue held, but the ferrite
> didn't....ugh!  The width of the ferrite from the outer edge to the
> inner ID edge is .950".  I also misjudged the width of the magnet
> and promptly learned that ferrite readily dulls drills..from that,
> it would appear that trying to rework ferrite alone is a tough task.
> 
I have successfully enlarged the gap in a speaker manget assembly on a
lathe. The magnet holds all the cuttings in the gap, this makes it hard
to see what you are doing and cut smoothly. Also the soft iron is gummy
and cuts more like copper than steel. It however can be done with light
cuts and a lot of patience.

The way to spearate the glue is with heat. If you are careful you can
soften the glue before you reach the Curie temp. of the ferrite.

Ferrite is really hard. I dulled a carbide drill enlarging a hole in a
ferrite bead that I was using for a flux gate magnetometer.
-- 
Jim Hannon
http://soli.inav.net/~jmhannon/
42,11.90N 91,39.26W
WB0TXL


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From: bschafer@.........
Subject: KFWB news clip
Date: Wed, 22 Jul 1998 23:58:57 -0500 (CDT)

Here is something that I heard on the news and thought it might be of 
interest.  I ran and got my tape recorder and got exactly what was said.  
Here it is following.


"Your greatest risk may not be from the San Andreas or the big 
mountain-building thrust faults.  KFWB's Jack Popejoy reports the study
combined GPS data with traditional geology.
Study co-author Dr. James Dolan of the Southern California Earthquake 
Center tells KFWb this doesn't change the overall seismic risk just our 
understanding of the risk the smaller surface faults running right 
through the urban area present.  "A lot more energy is being stored up 
on certain faults that we call strike slip faults--more than we thought 
in the past.  The flip side of that is that that energy that is being 
stored up on the strike slip faults isn't being stored on the big thrust 
faults that are building our mountains."  "The four leading strike slip
fault candidates in the study are the Verdugel fault, the Raymond,
the San Josae, and the Chino fault.  You can find them through the KFWB
web service at kfwb.com.  Just go to our news page."

Anyway, thought that was very interesting.  I thought that most faults 
in the Southern California area are strike slip faults.

Also, please forgive my spelling on some of these names.



Bonnie
the crafty crafter

 



Bonnie
the crafty crafter


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From: Norman Davis WB6SHI 
Subject: Re: Owens Valley
Date: Thu, 23 Jul 1998 07:35:15

At 07:20 PM 7/22/98 -0700, you wrote:
>I was listening to NPR with regards to the restoring water to the
>Owens Valley. That area has been awfully quiet since the 1872 event. Has
>anyone heard about the potential affect of the restoring water to the
>valley and it's affect on potential earthquakes? 
>                                  Barry

 The big deal in the owens goes back to the 20's. LA water and power
purcased all the land and then sold it without water rights. then took all
they wanted for use in LA. They also created lakes in the sierra and take
all that too. It has been at times a war like environment between the folks
up there and LA. That may be what they are talking about.

 BTW: Just came back from a drive from big pin to bridgport. Lots of water.
No shaking. Rats....

Norman Davis WB6SHI
Shingle Springs, Ca
normd@.............
http://www.directcon.net/normd/index.htm


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From: Robert Avakian 
Subject: Re: Owens Valley
Date: Thu, 23 Jul 1998 10:47:46 -0700

This may be off the subject a bit but, Mono Lake is one of, if not the
last of the unique rangefront lakes not dired out by LAPW and a very
significant breeding area for various birds.  I first encountered the
lake in 1970 doing field work as a grad student.  It is a very
impressive and magical place.  Locals fought the water people and won a
landmark decision protecting the lake.  However, the LAPW people are
trying any number of ways to slip out of the decision and subsequent
agreements.  The lake is a real treat as are the Mono craters nearby.  

The Mono Lake Committee (the white hats) are at PO Box 29, Lee Vining,
CA, 93541.  They are also on the web, i believe.
Bob Avakian


Norman Davis WB6SHI wrote:
> 
> At 07:20 PM 7/22/98 -0700, you wrote:
> >I was listening to NPR with regards to the restoring water to the
> >Owens Valley. That area has been awfully quiet since the 1872 event. Has
> >anyone heard about the potential affect of the restoring water to the
> >valley and it's affect on potential earthquakes?
> >                                  Barry
> 
>  The big deal in the owens goes back to the 20's. LA water and power
> purcased all the land and then sold it without water rights. then took all
> they wanted for use in LA. They also created lakes in the sierra and take
> all that too. It has been at times a war like environment between the folks
> up there and LA. That may be what they are talking about.
> 
>  BTW: Just came back from a drive from big pin to bridgport. Lots of water.
> No shaking. Rats....
> 
> Norman Davis WB6SHI
> Shingle Springs, Ca
> normd@.............
> http://www.directcon.net/normd/index.htm
> 
> _____________________________________________________________________
> 
> Public Seismic Network Mailing List (PSN-L)
> 
> To leave this list email listserver@............. with the body of the
> message: leave PSN-L


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From: Edward Cranswick 
Subject: [Fwd: Santa Cruz Seismic Instruction Software]
Date: Thu, 23 Jul 1998 16:51:16 -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".

Jan-
	I thought that you, Steve, and Ted might do something, and I think that
I forwarded some kind of info to the PSN-L.  However, I was not really
connected with it myself, and I wasn't going to try to tell you guys
what you should do (what maybe I should have helped to do myself).  In
any case, the IRIS meeting does not get as much coverage as the AGU
meetin in San Francisco in December which Larry and Ted attended last
year with me.  So I think it would be a great idea to pursue the idea
that you and Ted talked about last year of having a bunch of students
submit a poster for the AGU meeting 6-10 December this year
. You guys can write the
abstract and prepare the poster and I, as an AGU member, can sponsor it
and get the USGS to pay for it. The abstract deadline for that is: 

	August 26, 1998		(Postal/express mail submissions)

        September 2, 1998	(Interactive Web Form submissions) 

	Because we only have about a month, please let me know ASAP what you
think and also CC a copy to me at  which what
I am trying to make my address for PSN-related activities.
-Edward

Jan Froom wrote:
> 
> It's a shame that we couldn't have gone to this conference, since I think
> Steve, Ted & I  are about the only ones in this area that are actually working
> with schools.... well Elementary, Middle & High.  I tried, and got a note from
> a lady in Arizona that forwarded my request to a lady in Santa Cruz....  but
> after that I got no answer.
> ---------------------- Forwarded by Jan Froom/San Jose/IBM on 07-22-98 11:26 AM
> ---------------------------
> 
> Ted Blank
> 07-21-98 01:13 PM
> To: Jan Froom/San Jose/IBM@IBMUS
> cc:
> From: Ted Blank/Santa Teresa/IBM @ IBMUS
> Subject: Re: Santa Cruz Seismic Instruction Software
> 
> I tried to get the information from Larry but it was all very vague.  Finally
> he called me the night before to say it was the next day but by that time I had
> other plans.  Oh well.
> 
> Regards, Ted
> DB2 Performance, IBM Santa Teresa Lab, San Jose, California
> 
> Ted Blank/Santa Teresa/IBM .....(from Notes)
> IBMUSM50(TED) .............................(from PROFS/VM)
> ted@.......... ..............................(from internet sites)
> STLVM6(BLANK) .............................(for LIST3820 files etc.)
> Tie: 8-543-3589    Ext:  (408) 463-3589   Fax:  (xxx-2614)

-- 
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: Papua New Guinea tsunami
Date: Thu, 23 Jul 1998 17:12:12 -0600

PSN-
    Here are three interesting and instructive websites about the Papua
New Guinea tsunami:

    http://omzg.sscc.ru/tsulab

    http://walrus.wr.usgs.gov/docs/tsunami/PNGhome.html

    http://www.theage.com.au/special/png/index.html

The human suffering in PNG is beginning to sound horrible.
-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".




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From: barry lotz 
Subject: Re: Owens Valley
Date: Thu, 23 Jul 1998 17:17:21 -0700

Greg
   The reason it came to mind was that I had heard of the increase in
seismic activity with the construction of certain dams(I don't remember
which). However dams do produce a much larger static head.
                                        Barry
 
Greg wrote:
> 
> barry lotz wrote:
> 
> > anyone heard about the potential affect of the restoring water to the
> > valley and it's affect on potential earthquakes?
> 
> In Tucson, Arizona the city is supposedly "recharging the water supply"
> with water routed from somewhere else? I'm somewhat new here and I don't
> know all of the facts, but no earthquakes yet ;) I doubt the water is
> being forced in under any pressure like the Denver deal.
> 
> ,Greg
>

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From: Robert Avakian 
Subject: Re: Owens Valley
Date: Thu, 23 Jul 1998 20:01:04 -0700

As I remeber, the seismic activity was atrtributed to the loading of the
water, too.


barry lotz wrote:
> 
> Greg
>    The reason it came to mind was that I had heard of the increase in
> seismic activity with the construction of certain dams(I don't remember
> which). However dams do produce a much larger static head.
>                                         Barry
> 
> Greg wrote:
> >
> > barry lotz wrote:
> >
> > > anyone heard about the potential affect of the restoring water to the
> > > valley and it's affect on potential earthquakes?
> >
> > In Tucson, Arizona the city is supposedly "recharging the water supply"
> > with water routed from somewhere else? I'm somewhat new here and I don't
> > know all of the facts, but no earthquakes yet ;) I doubt the water is
> > being forced in under any pressure like the Denver deal.
> >
> > ,Greg
> >
> 
> _____________________________________________________________________
> 
> Public Seismic Network Mailing List (PSN-L)
> 
> To leave this list email listserver@............. with the body of the
> message: leave PSN-L



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From: Mike Lozano 
Subject: Re: Owens Valley
Date: Fri, 24 Jul 1998 06:49:40 -0500



barry lotz wrote:

> Greg
>    The reason it came to mind was that I had heard of the increase in
> seismic activity with the construction of certain dams(I don't remember
> which). However dams do produce a much larger static head.
>                                         Barry
>
> Greg wrote:
> >
> > barry lotz wrote:
> >
> > > anyone heard about the potential affect of the restoring water to the
> > > valley and it's affect on potential earthquakes?
> >
> > In Tucson, Arizona the city is supposedly "recharging the water supply"
> > with water routed from somewhere else? I'm somewhat new here and I don't
> > know all of the facts, but no earthquakes yet ;) I doubt the water is
> > being forced in under any pressure like the Denver deal.
> >
> >

Barry,

A few dams suffering increased seismic activity after filling are:  Hoover Dam
had a 5.0 in 1940.  Since that time, reportedly, seismicity has decreased.
All the quakes were on the east side of the dam, with a focal depth of less
than 8 km.

Lake Kariba in Zambia (filled in 1958) had a 5.8 in 1963, and decreased
activity since.
It was the last quake in a series of 2000 minor tremors.

Koyna, India had a 6.5 in 1967 which killed 200 and injured 1500.  Seismic
activity has generally followed rainfall patterns.

The filling of the Aswan High Dam on Lake Nasser has set off numerous quakes,
the heaviest of which, happened in 1981.

Funny, I was just browsing through Bruce Bolt's 'Earthquake' when your email
comment popped up on my screen.

Regards, Mikel Lozano



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From: barry lotz 
Subject: Re: Owens Valley
Date: Thu, 23 Jul 1998 19:21:14 -0700

Mike & Greg
    Thanks for the feedback.
                 Barry

>Mike Lozano wrote:
> 
> Barry,
> 
> A few dams suffering increased seismic activity after filling are:  Hoover Dam
> had a 5.0 in 1940.  Since that time, reportedly, seismicity has decreased.
> All the quakes were on the east side of the dam, with a focal depth of less
> than 8 km.
> 
> Lake Kariba in Zambia (filled in 1958) had a 5.8 in 1963, and decreased
> activity since.
> It was the last quake in a series of 2000 minor tremors.
> 
> Koyna, India had a 6.5 in 1967 which killed 200 and injured 1500.  Seismic
> activity has generally followed rainfall patterns.
> 
> The filling of the Aswan High Dam on Lake Nasser has set off numerous quakes,
> the heaviest of which, happened in 1981.
> 
> Funny, I was just browsing through Bruce Bolt's 'Earthquake' when your email
> comment popped up on my screen.
> 
> Regards, Mikel Lozano

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From: frankcnd@.......... (Frank Condon)
Subject: Re: Owens Valley
Date: Thu, 23 Jul 1998 22:06:42 -0700 (PDT)

From what I've heard the Owens River Valley was kind of like the bread 
basket of the Eastern Sierras in it's heyday before the LA aqueduct.

Frank Condon
"Located in the Seismic Corridor Somewhere Between Fontana & Mammoth Lakes"

>At 07:20 PM 7/22/98 -0700, you wrote:
>>I was listening to NPR with regards to the restoring water to the
>>Owens Valley. That area has been awfully quiet since the 1872 event. Has
>>anyone heard about the potential affect of the restoring water to the
>>valley and it's affect on potential earthquakes? 
>>                                  Barry
>
> The big deal in the owens goes back to the 20's. LA water and power
>purcased all the land and then sold it without water rights. then took all
>they wanted for use in LA. They also created lakes in the sierra and take
>all that too. It has been at times a war like environment between the folks
>up there and LA. That may be what they are talking about.
>
> BTW: Just came back from a drive from big pin to bridgport. Lots of water.
>No shaking. Rats....
>
>Norman Davis WB6SHI
>Shingle Springs, Ca
>normd@.............
>http://www.directcon.net/normd/index.htm
>
>
>_____________________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email listserver@............. with the body of the 
>message: leave PSN-L
>
>


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From: Edward Cranswick 
Subject: is there anybody out there?
Date: Fri, 24 Jul 1998 12:51:13 -0600

Larry-
    I posted two messages to the PSN-L yesterday and have received no
acknowlegement that they were received and neither have been posted.  Is it me
or you or both of us?
--
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".




_____________________________________________________________________

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From: Canie Brooks 
Subject: Re: is there anybody out there?
Date: Fri, 24 Jul 1998 11:56:21 -0700

They are there!  I've gotten them - one on AGU and seismic instruction
software and another on the PNG tsunamis...

Canie

At 12:51 PM 7/24/98 -0600, Edward Cranswick wrote:
>Larry-
>    I posted two messages to the PSN-L yesterday and have received no
>acknowlegement that they were received and neither have been posted.  Is
it me
>or you or both of us?
>--
>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
> 

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From: S-T Morrissey 
Subject: Re: Owens Valley
Date: Fri, 24 Jul 1998 19:14:40 -0500 (CDT)

Re induced seismicity from reservoirs:

I had the opportunity of working in the USSR exchange program in
the late '70s on installing seismic telemetry around large reservoirs
that had the potential of inducing seismicity or modifying the
release of accumulating slip potential. The first was the 350 meter
high Nurek reservoir near Dushanbe in Tadjikistan on the Naryn
river just west of the Hindu Kush ranges. The other was at Totugul
in Kirgisia, on the Talas-Fergana fault system. The Nurek reservoir
would cause quakes anytime the level was rapidly dropped, like more
than 10 meters per day. This would unburden the pressure on the 
faults, alowing the high pore pressure induced  by the impoundment
to lubricate the faults. Raising the water level would turn off
the quakes.
A general rule of thumb for induced seismicity is that the impoundment
has to exceed 100 meters in depth. The general concept is that the
hydrostatic pore pressure increase and/or the vertical load do not
of themselves cause earthquakes, but modify the way accumulating
regional stress is released.
I doubt if refilling Mono lake would in itself induce seismicity;
The Owens valley has enough potential of its own.

Regards,
Sean-Thomas

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From: bschafer@.........
Subject: cranswick@......................
Date: Fri, 24 Jul 1998 19:27:59 -0500 (CDT)

is there anybody out there?
  
Hi, just got this message loud and clear and thought I would let you 
know.

Just got a very good book written by Bruce Bolt called "Earthquakes."  A 
very good and well written book for the person who doesn't know much 
about seismology.  He had another one there but didn't have enough cash 
to get it right then.  I saw it at Borders bookstore.


Bonnie
the crafty crafter


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From: S-T Morrissey 
Subject: STM-8 drawings
Date: Fri, 24 Jul 1998 20:17:15 -0500 (CDT)

I have finally posted the latest drawings of the hardware-
store seismometer on the web site at:

http://www.eas.slu.edu/People/STMorrissey/index.html

under the "figures and drawings" page. The seismometer
drawings are of two dimensions only; the overhead view
can generally be deduced from the side view because of
the natural symmetry of the design.

Regards,
Sean-Thomas

_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: Edward Cranswick 
Subject: Include PSN in seismic network survey?
Date: Fri, 24 Jul 1998 21:33:27 -0600

PSN-
    As usual, I am passing this on a bit late, but I am still trying to
unravel the enigmatic link or lack thereof I have with the PSN-L.  So I
am sending this out to see our response.
-Edward

********************************************************************
Subject:
         Request for network information
   Date:
         Wed, 8 Jul 1998 10:23:28 -0700 (PDT)
   From:
         Steve Malone 

I have sent e-mail to all of the official CNSS network representatives
and
alternates regarding the need for information for an "Assessment of
Seismic Monitoring in the US" and a contribution to an IASPEI
publication.
If anyone associated with a regional network who should have gotten
this notice but did not you may find it posted on the WEB at URL:

        http://www.cnss.org/NETS/request.survey.txt

Please try to make sure that any seismic network you are associated with

will be responding to this request.

        Thanks,


        Steve Malone                    E-mail:
steve@......................
        Geophysics Program              Phone: (206) 685-3811
        University of Washington        FAX: (206)543-0489
        Box 351650                      Office: ATG-226
        Seattle, WA 98195       http://www.geophys.washington.edu



--
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: meredith lamb 
Subject: Re: STM-8 drawings
Date: Fri, 24 Jul 1998 23:00:15 -0600



S-T Morrissey wrote:

> I have finally posted the latest drawings of the hardware-
> store seismometer on the web site at:
>
> http://www.eas.slu.edu/People/STMorrissey/index.html
>
> under the "figures and drawings" page. The seismometer
> drawings are of two dimensions only; the overhead view
> can generally be deduced from the side view because of
> the natural symmetry of the design.
>
> Regards,
> Sean-Thomas
>

Thanks for posting the new drawings on the web site.  Took off
3 drawings: Leafspring 4, Vertseis 5 & 6 drawings with no problem.
The enhanced Vertseis 6, seemed to be much clearer here.

A magnificent public contribution....

Thanks, Meredith Lamb




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From: meredith lamb 
Subject: Re: Papua New Guinea tsunami
Date: Fri, 24 Jul 1998 23:03:27 -0600

Edward Cranswick wrote:

> PSN-
>     Here are three interesting and instructive websites about the Papua
> New Guinea tsunami:
>
>     http://omzg.sscc.ru/tsulab
>
>     http://walrus.wr.usgs.gov/docs/tsunami/PNGhome.html
>
>     http://www.theage.com.au/special/png/index.html
>
> The human suffering in PNG is beginning to sound horrible.
> -Edward
> --

It indeed does appear to be a big disaster.  Perhaps a part of
the replication is the economics, life span, life style, education,
etc.  Sad results that are more a fact of life in alot of parts of the
world, and hard to write about.

Makes me wish that there was perhaps some form of a cheap
seismic instrumentation available that might help save some lives.
For remote and electrical powerless locations like that, solar
sun cells would work for rechargeables....but the cost just for
those items would be prohibitive in their economy, and there
likely isn't any real knowleable and responsible party in every
village.  True, for this quake, some 12 odd miles/kilometers
offshore they would have felt it strongly; but for more distant
quakes, they may not, and yet....get the same results.

I'am not aware of any government promotion of earthquake
awareness outside the U.S., Japan, and China.  Its possible
they simply can't afford even simple equipment to distrubute
over numerious villages etc.  Communication equipment is not
likely even considered, due to higher cost, and also it is not
automated in response or alarm.

For power saving features, it would almost seem to be essential
to use power saving items like eddy current damping of the
seismometer.  Any circuit would have to operate on minimum
battery draw.  Such a circuit would likely have to have some kind
of audio alarm for threshold exceeded limits.  Waterproof.  Likely
buried for long term.  Geophones are probably the most
attractive candidates for such a scheme.....if there is any undertaken
.....wherever...and if ever...

I know you're strong on earthquake safety and awareness.  Perhaps with
time, better and cheaper instrumentation can assist in reducing any
quake loss results due to limited budgets, and; increase more critical
concerned public personnel like yourself.  Here or abroad.


Meredith Lamb


_____________________________________________________________________

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From: meredith lamb 
Subject: Re: Include PSN in seismic network survey?
Date: Sat, 25 Jul 1998 00:31:14 -0600

Hi Edward,

Seems too me, you "enigmatic" (puzzling) link to PSN has been
around about 15 years-ha.  Guess you will have to accept the
fact of your convictions, that a wider arena (PSN), has brought
both enlightenment to yourself and mostly to us....as students.

Summertime silence on PSN.  Happens every year is my guess.

Anyway....checked out the survey list.  Do have a question or
two.  I can't quite believe they list Wood-Andersons horizontal
seismometers thereon?  I thought that went out with the great
extinctions-ha.  Probably the simplest design ever created.  Hmmm,
maybe with newer sensors attached it could come back........
like...with a vrdt or ?   No joke meant here.  Simpler is better.
Equipment is always a major hurdle with anybody, government
or private amateur.

The survey looks like it is a re-creation of a much older document.
Photo recording?  No one I know of....    The 24 bit recording is
a possible future dream.....

The survey is revealing, interesting, puzzling with the abbreviations,
kind of elongated with mystic reasoning redish tape, and etc.
Uhhh......YOU... do... understand all that stuff don't you?-ha.

Alot of things have changed in your 15 years, there weren't there
before.  More things will change in the future...and you'll be there to
be a part of it...

Thanks for the survey surprise.

Meredith Lamb



_____________________________________________________________________

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From: watson@................ (Charles Watson)
Subject: Re: Papua New Guinea tsunami
Date: Sat, 25 Jul 1998 08:46:24 -0700

Meredith -

Noble words. It was following last year's NE Venezuela 7.1 earthquake that 
my bell rang. In reporting on the event, I was in constant contact with a 
Venezuela Newspaper, radio station and the University. I heard first hand of 
the rescue efforts for two schools which totally collasped killing all or 
most the children and their teachers inside. It wrenched my guts out as the 
radio station broadcasted live over the internet a rescue team's failed 
attempts to save a small child trapped in the school rubble. Just as they 
broke an openning to reach her, an aftershock hit and brought more rubble 
down, sealing the childs fate and injuring some of the rescue workers. 
Really, really horrible. 

But what's really sad is these losses could have been prevented by better 
building codes and improved siting of critical structures like schools, 
hospitals, etc. It was a known area of strong earthquake activity and yet 
they continued to build in the soft sediments around the bay. Unfortuantely, 
this kind of disaster is not restricted to the third world. I pray when the 
Hayward or Seattle faults (just to name a pair) rupture that they are of 
modest magnitudes rather that their maximum crediable.

Prior to the Venezuela earthquake, I had almost a boyish passion to tracking 
earthquake activity. The larger the better and I wished I could be there to 
feel the energy released from the rupture. While the passion is still there, 
it is tempered with the reality that some of these large earthquakes will 
occur on land and cause extreme trauma to the region. My role in the seismic 
reporting world has changed and I emphasis early detection and warning, 
along with preparedness before, during and after the earthquake.

There has been much descussion about the early warning systems but none 
implimented here in the States. Anyone know of the progress towards 
establishing these systems?

-- 
---/----
Charles P. Watson
Seismo-Watch

meredith lamb wrote:
> 
> Edward Cranswick wrote:
> 
> > PSN-
> >     Here are three interesting and instructive websites about the Papua
> > New Guinea tsunami:
> >
> >     http://omzg.sscc.ru/tsulab
> >
> >     http://walrus.wr.usgs.gov/docs/tsunami/PNGhome.html
> >
> >     http://www.theage.com.au/special/png/index.html
> >
> > The human suffering in PNG is beginning to sound horrible.
> > -Edward
> > --
> 
> It indeed does appear to be a big disaster.  Perhaps a part of
> the replication is the economics, life span, life style, education,
> etc.  Sad results that are more a fact of life in alot of parts of the
> world, and hard to write about.
> 
> Makes me wish that there was perhaps some form of a cheap
> seismic instrumentation available that might help save some lives.
> For remote and electrical powerless locations like that, solar
> sun cells would work for rechargeables....but the cost just for
> those items would be prohibitive in their economy, and there
> likely isn't any real knowleable and responsible party in every
> village.  True, for this quake, some 12 odd miles/kilometers
> offshore they would have felt it strongly; but for more distant
> quakes, they may not, and yet....get the same results.
> 
> I'am not aware of any government promotion of earthquake
> awareness outside the U.S., Japan, and China.  Its possible
> they simply can't afford even simple equipment to distrubute
> over numerious villages etc.  Communication equipment is not
> likely even considered, due to higher cost, and also it is not
> automated in response or alarm.
> 
> For power saving features, it would almost seem to be essential
> to use power saving items like eddy current damping of the
> seismometer.  Any circuit would have to operate on minimum
> battery draw.  Such a circuit would likely have to have some kind
> of audio alarm for threshold exceeded limits.  Waterproof.  Likely
> buried for long term.  Geophones are probably the most
> attractive candidates for such a scheme.....if there is any undertaken
> ....wherever...and if ever...
> 
> I know you're strong on earthquake safety and awareness.  Perhaps with
> time, better and cheaper instrumentation can assist in reducing any
> quake loss results due to limited budgets, and; increase more critical
> concerned public personnel like yourself.  Here or abroad.
> 
> Meredith Lamb
> 
> _____________________________________________________________________
> 
> Public Seismic Network Mailing List (PSN-L)
> 
> To leave this list email listserver@............. with the body of the
> message: leave PSN-L

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From: Mike Lozano 
Subject: Re: Papua New Guinea tsunami
Date: Fri, 24 Jul 1998 19:05:47 -0500

Charles & Meredith & everyone else,

It was with a great deal of interest that I read both of your messages.  It's so
true that every time we see a gigantic squiggle, someone else pays the price.  I
face the same thing in my field of meteorology.  Everytime there's a microburst
or tornado or hail, etc.,etc... someone pays the price; but the years of
intrepreting data and drawing conclusions has begun to pay off in the earlier
warnings we're seeing now.  Just 2 weeks ago, the Des Moines area was hit with a
large tornado.  Due to the early warning generated by doppler radar and
mesoscale analysis algorithms (some of which I had a miniscule part in
developing), no one died.  Hopefully, at some time in the future, earthquakes
and tsunami will be as predictable.

On your other note, a few years ago, I developed a lahar warning device that is
so cheap it's considered expendable.  It's solar charged, consumes 50
microamperes, and is pretty much fail-safe.  I even got a patent on it (mostly
for my own vanity), and offered it to a university (I now forget if it was the
Univ. of Michigan) for free.  Guess what?  I never even received a reply to my
offer.  So much for the advancement of affordable warning devices.  I hope I'm
not stepping on any toes, but sometimes the "not invented here" syndrome is
alive and well - unfortunately, the cost is to those who don't wind up alive and
well.

comments?

Mikel Lozano
-0-


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From: Fred S 
Subject: Re: Papua New Guinea tsunami
Date: Sat, 25 Jul 1998 12:36:37 -0700

Meredith, In a situation like PNG or any other place 
of poor economy and high risk. It seems a low cost GO/NO GO 
system could be implimented. The actual magnitude and location 
is not so important as just an indication of an event exceeding a
pre-set threshold. 

What about low cost geophones like the type used in oil exploration. I
have been using these to monitor local activity with good results.
Coupled with some low power CMOS electronics and a simple burst type
transmitter. This could be a low cost alternative to a complicated
network.

Fred

-- 
Gravity:  It's not just a good idea.  It's the LAW !

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From: watson@................ (Charles Watson)
Subject: Re: Papua New Guinea tsunami
Date: Sat, 25 Jul 1998 14:23:30 -0700

Mikel -

I have mixed feelings too. Sometimes I have looked at the squiggles on =

the seismograph and wondered: Wow, that=B9s a big one! where was it! =

surface fault ruptures?... But then reality sets in: who was =

effected?...who suffered?...who died this time?... At almost the same =

time, my scientific side of me is charged with excitement, but the other =

is sadden by the potential loss and suffering.

Perhaps under different situations the value of human life would be =

elevated. In some situations we, as a species, are willing to risk one =

life in order save an other. But in the harsh world of global economics =

and product development, the amount of lives saved is factored into the =

financial cost. Product cost vs. lives saves - and erie thought on its =

own, the price of human life vs. product development. If life is so =

valuable, why are willing to expend the ultimate sacrifice, another =

human life, just to save one other. But when thousands of lives could be =

save at a profit in product development, we jump on the campaign and =

indeed it is done. Or sadly in turn, not choose a product because it =

does not save enough lives for the amount spent.

And then there is art, science, and medicine. There is a fine line an =

artist, scientist, or physician must walk in order to do their job - to =

compose the emotional distraught scene, determine the answers to some =

pretty tough questions, or perform a difficult procedure in surgery - =

some of which may mean maybe one or hundreds of human lives were either =

lost or saved. I admire the experts in their fields, yet understand the =

pain they must have endured to achieve their status. Wise people must =

endure suffering, therefore, wisdom comes at a valuable cost, one beyond =

financial measure. =


I often look at the PSN group as people with wisdom beyond their years. =

The potential is greater than the current sum, knowing the mean will =

satisfy the many. =



                                       - Charlie



-- =

---/----
Charles P. Watson, Consulting Geologist
Advanced Geologic Exploration/Seismo-Watch
P.O. Box 18012, Reno, Nevada 89511
Voice: 702-852-0992  /  Fax: 702-852-3226 =

mailto:watson@................
http://www.seismo-watch.com

_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: Steve Hammond 
Subject: Re: Include PSN in seismic network survey?
Date: Sat, 25 Jul 1998 13:44:18 -0700

I think it is important for use to be included in this listing. We
contribute to the international record and have been contributing for
eight years. I took the liberty of going to Dave=92s WEB site and
downloading the text list of all the stations. We have the data together
it just needs to be formatted. Does anybody feel we should not submit
this to the Office of CNSS?If not I need just a little help to assemble
Dave=92s New Zealand station PSN station Site listing into the proper
format. Can you look at this URL

http://www.iris.washington.edu/manuals/acrobat/SEED_A_only.pdf

and define the shackle-ford-gundersen, Lehman, geophone <10 sec
response. I want to make sure I get it right-- And anybody with good
eye=92s might look over our station list and add other=92s like the AS-1.
Please look over these items and contribute. Also, if you don=92t want to
be included please tell me.

----Hey Larry! ---- how much data do we have on-line and off-line now? I
have 500MB or so on CD-ROM from the original BBS network.

The deadline is the end of July folks--

Regards, Steve Hammond   PSN San Jose, California



Edward Cranswick wrote:
>=20
> PSN-
>     As usual, I am passing this on a bit late, but I am still trying to
> unravel the enigmatic link or lack thereof I have with the PSN-L.  So I
> am sending this out to see our response.
> -Edward
>=20
> ********************************************************************
> Subject:
>          Request for network information
>    Date:
>          Wed, 8 Jul 1998 10:23:28 -0700 (PDT)
>    From:
>          Steve Malone 
>=20
> I have sent e-mail to all of the official CNSS network representatives
> and
> alternates regarding the need for information for an "Assessment of
> Seismic Monitoring in the US" and a contribution to an IASPEI
> publication.
> If anyone associated with a regional network who should have gotten
> this notice but did not you may find it posted on the WEB at URL:
>=20
>         http://www.cnss.org/NETS/request.survey.txt
>=20
> Please try to make sure that any seismic network you are associated wit=
h
>=20
> will be responding to this request.
>=20
>         Thanks,
>=20
>         Steve Malone                    E-mail:
> steve@......................
>         Geophysics Program              Phone: (206) 685-3811
>         University of Washington        FAX: (206)543-0489
>         Box 351650                      Office: ATG-226
>         Seattle, WA 98195       http://www.geophys.washington.edu
>=20
> --
> 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".
>=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

_____________________________________________________________________

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From: Greg 
Subject: Re: Papua New Guinea tsunami
Date: Sat, 25 Jul 1998 15:37:48 -0700

I noticed nobody mentioned the Tsunami Warning Center(s) yet. 

I found this site while poking around the internet today:
http://www.unesco.org/ioc/oceserv/itsu/itic.htm

Maybe the earthquake happened too close to give enough warning? There's
not really too much you can do if you have any warning, except try to
leave? If everyone knew the instant the earthquake happened that there's
was a tsunami coming would it have been enough time? I think the only
way this can be prevented is if the earthquake and tsunami are expected
well in advance of the actual event. 

,Greg

_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: Jim Hannon 
Subject: Re: Papua New Guinea tsunami
Date: Sat, 25 Jul 1998 21:27:15 -0500

Mike Lozano wrote:
> 
> Charles & Meredith & everyone else,
> 
> It was with a great deal of interest that I read both of your messages.  It's so
> true that every time we see a gigantic squiggle, someone else pays the price.  I
> face the same thing in my field of meteorology.  Everytime there's a microburst
> or tornado or hail, etc.,etc... someone pays the price; but the years of
> intrepreting data and drawing conclusions has begun to pay off in the earlier
> warnings we're seeing now.  Just 2 weeks ago, the Des Moines area was hit with a
> large tornado.  Due to the early warning generated by doppler radar and
> mesoscale analysis algorithms (some of which I had a miniscule part in
> developing), no one died.  Hopefully, at some time in the future, earthquakes
> and tsunami will be as predictable.
> 
> On your other note, a few years ago, I developed a lahar warning device that is
> so cheap it's considered expendable.  It's solar charged, consumes 50
> microamperes, and is pretty much fail-safe.  I even got a patent on it (mostly
> for my own vanity), and offered it to a university (I now forget if it was the
> Univ. of Michigan) for free.  Guess what?  I never even received a reply to my
> offer.  So much for the advancement of affordable warning devices.  I hope I'm
> not stepping on any toes, but sometimes the "not invented here" syndrome is
> alive and well - unfortunately, the cost is to those who don't wind up alive and
> well.
> 
> comments?
> 
> Mikel Lozano
> -0-
I had to look up "lahar" to see what it was. :)

The death and destruction caused by human activity such as war causes me
much more pain that that caused by natural disasters.
-- 
Jim Hannon
http://soli.inav.net/~jmhannon/
42,11.90N 91,39.26W
WB0TXL


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From: S-T Morrissey 
Subject: period/mass etc of STM
Date: Sat, 25 Jul 1998 22:43:35 -0500 (CDT)

Barry,
To finally answer your question about the period adjustment of the
STM seis vs the mass. Moving the leaf spring contact point
along the boom toward the hinges does increase the period 
while requiring a slight reduction of the mass. However, the
adjustment from a period of several seconds to instability is 
only about 10 mm, so the change in the mass is relatively minor,
and was accomplished by moving the 20 gram brass trim mass.
This is because the adjustment is within the range of the 
"zero length" behavior of the spring, where the restoring
force is relatively constant over a small change of the spring
length, or opening in the case of the leaf spring.
The change in the mechanical period does affect the damping
of the VBB feedback configuration.

Regarding a change in the sensitivity with a change in the mass:
the value of the mass appears in most of the terms of the 
transfer function, so changing it does affect the shape of the overall
response. However, this effect of a 10% change on the shape of the
response is not serious. But the mass value is also part of the
constant term, so a 10% increase of the mass does produce a 10% 
increase in the output sensitivity (in volts/meter/second).

In the drawing of the seis that I have posted, the dimensions
indicated result in  a mechanical period of about 10 seconds, 
(with the base level and with the reduced dimensions of the flexures)
which is fine for a VBB feedback configuration of 90 seconds.

Regards,
Sean-Thomas

_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: Edward Cranswick 
Subject: Re: is there anybody out there?
Date: Sat, 25 Jul 1998 21:58:46 -0600

Larry, John, Canie & Jim-
    Thank you for your responses which I am receiving.  However, I am not
receiving notification that my mail has been received by PSN-L nor I am
receiving the messages themselves from PSN-L that I send even though I am
receiving the messages others, e.g., like yours.
-Edward

Larry Cochrane wrote:

> Your messages are coming through just fine. Let me know if you get this.
>
> -Larry
>
> At 12:51 PM 7/24/98 -0600, you wrote:
> >Larry-
> >    I posted two messages to the PSN-L yesterday and have received no
> >acknowlegement that they were received and neither have been posted.  Is
> it me
> >or you or both of us?
> >--
> >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
> >



--
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: cranswick@......................
Date: Sat, 25 Jul 1998 22:13:49 -0600

Bonnie-
    Thank you for your message telling me it's all OK. I have not read the
Bolt book though I have heard good things about it.  I wish I had had a copy
of it or one of his other introductory texts when I taught a course at the
American University of Armenia in Yerevan in 1992 entitled, "Introduction to
High-frequency Digital Seismic Data Acquisition, Processing and Analysis for
Strong Ground Motion Studies", that was supposed to be a warmup for the
seismology class he taught later that year.  I  drank alot of vodka instead
to try to compensate for my ignorance of some seismological fundamentals.
-Edward

bschafer@......... wrote:

> is there anybody out there?
>
> Hi, just got this message loud and clear and thought I would let you
> know.
>
> Just got a very good book written by Bruce Bolt called "Earthquakes."  A
> very good and well written book for the person who doesn't know much
> about seismology.  He had another one there but didn't have enough cash
> to get it right then.  I saw it at Borders bookstore.
>
> Bonnie
> the crafty crafter
>
> _____________________________________________________________________
>
> 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: "Walt Williams" 
Subject: Re: Papua New Guinea tsunami
Date: Sat, 25 Jul 1998 22:56:10 +0000

Hello Mike,

Pardon my ignorance, but is a:
"lahar warning device"?

Thank you.

Walt Williams, 98.07.25
dfheli@..............
========================================

------- Forwarded Message Follows -------
Date:          Fri, 24 Jul 1998 19:05:47 -0500
From:          Mike Lozano 
Reply-to:      PSN-L Mailing List 
Organization:  Applied Sciences, Ltd.
To:            PSN-L Mailing List 
Subject:       Re: Papua New Guinea tsunami

Charles & Meredith & everyone else,

It was with a great deal of interest that I read both of your
messages.  It's so true that every time we see a gigantic squiggle,
someone else pays the price.  I face the same thing in my field of
meteorology.  Everytime there's a microburst or tornado or hail,
etc.,etc... someone pays the price; but the years of intrepreting data
and drawing conclusions has begun to pay off in the earlier warnings
we're seeing now.  Just 2 weeks ago, the Des Moines area was hit with
a large tornado.  Due to the early warning generated by doppler radar
and mesoscale analysis algorithms (some of which I had a miniscule
part in developing), no one died.  Hopefully, at some time in the
future, earthquakes and tsunami will be as predictable.

On your other note, a few years ago, I developed a lahar warning
device that is so cheap it's considered expendable.  It's solar
charged, consumes 50 microamperes, and is pretty much fail-safe.  I
even got a patent on it (mostly for my own vanity), and offered it to
a university (I now forget if it was the Univ. of Michigan) for free. 
Guess what?  I never even received a reply to my offer.  So much for
the advancement of affordable warning devices.  I hope I'm not
stepping on any toes, but sometimes the "not invented here" syndrome
is alive and well - unfortunately, the cost is to those who don't wind
up alive and well.

comments?

Mikel Lozano
-0-


_____________________________________________________________________

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_____________________________________________________________________

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From: "David A. Nelson" 
Subject: Re: (Fwd) Re: Papua New Guinea tsunami
Date: Sun, 26 Jul 1998 20:00:05 +1200

At 10:56 PM 7/25/98 +0000, you wrote:
>Hello Mike,
>Pardon my ignorance, but is a:
>"lahar warning device"?
>Thank you.
>Walt Williams, 98.07.25
>dfheli@..............


 Hi Walt,
                Lahars  =  mud flows,   usually referring to ones  from the
sides of volcanoes.
 since the loss of a passenger train and 153 lives on Xmas eve1953 when a
lahar washed out the rail bridge,   warning devices are now in place along
parts of the several rivers that come off Mt Ruapehu.   This mountain being
one of the active volcanoes in the Nth Island of New Zealand.    
   the lahar in 1953 was not caused by an eruption... rather the fragile
crater wall collapsed allowing the crater lake to partly empty as a huge mud
laden flow into the river channel down the mountain.   
   the detectors that have now been installed give early warning to road and
rail traffic approaching bridges in the area  b4 those bridges are crossed.

  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


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From: Bob Fryer 
Subject: Re: Papua New Guinea tsunami
Date: Sun, 26 Jul 1998 01:12:54 -0700

Hello Greg,

For those within 50 to 100 miles of a quake, the quake itself is the
warning.  On July 12, 1993 at Okushiri Island, Japan, an M7.8 struck 44
miles offshore.  Many of those who immediately headed for high ground from
the fishing port of Aonae were spared from the tsunami which first struck
about 5 minutes later, as warnings were being issued on Hokkaido.  At least
160 people died on the island, including the 35 fatalities in a hotel
struck by a landslide.

A major complication in the New Guinea event was that many of the villages
were on a sand spit -- there was no escape.

The town of Seaside, Oregon faces a similar problem -- the bridges needed
for escape will likely be destroyed by the quake which is expected sometime
in the next hundred years.  Wide areas of the Northwest coast, from
northern California to Vancouver Island, were inundated by the massive
tsunamis generated by the estimated M9.2 quake in January of 1700.  The
expected quake will likely range from M8.0 to 8.5.

Bob Fryer  -- on the Cascadia Subduction Zone


>I noticed nobody mentioned the Tsunami Warning Center(s) yet.
>
>I found this site while poking around the internet today:
>http://www.unesco.org/ioc/oceserv/itsu/itic.htm
>
>Maybe the earthquake happened too close to give enough warning? There's
>not really too much you can do if you have any warning, except try to
>leave? If everyone knew the instant the earthquake happened that there's
>was a tsunami coming would it have been enough time? I think the only
>way this can be prevented is if the earthquake and tsunami are expected
>well in advance of the actual event.
>
>,Greg

----- earthquake WARNING research -----
--- animals, people, scientific evidence ---
---  http://www.teleport.com/~bfryer ---



_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: barry lotz 
Subject: Re: period/mass etc of STM
Date: Sun, 26 Jul 1998 06:56:11 -0700

S-T Morrissey wrote:
Sean Thomas
   Thanks for getting back to me. Last week I ran a calibration on my
capacitive displacement transducer and the sensitivity was high and
linear. the problem I had was over a 20+ sec the output would drift. It
might have been mechanical but it seemed more like electrical. I am
trying an LVDT now. There was a thread back a while regarding LVDT vs
Capacitive sensor verses VRDT. I can't remember the particular result of
that discussion. I will get around to testing all three to convince
myself which works for me. I'm trying to keep the electronics as simple
as possible and yet get the sensitivity. I haven't looked at your recent
updated site yet. Looking forward to it.
                                        
Regards                               
                                         Barry

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Public Seismic Network Mailing List (PSN-L)


From: barry lotz 
Subject: Re: Papua New Guinea tsunami
Date: Sun, 26 Jul 1998 07:03:40 -0700

Bob,Greg
   I think Hawaii have a similar warning system when a large event is
recorded from around the rim.
                          Barry

Bob Fryer wrote:
> 
> Hello Greg,
> 
> For those within 50 to 100 miles of a quake, the quake itself is the
> warning.  On July 12, 1993 at Okushiri Island, Japan, an M7.8 struck 44
> miles offshore.  Many of those who immediately headed for high ground from
> the fishing port of Aonae were spared from the tsunami which first struck
> about 5 minutes later, as warnings were being issued on Hokkaido.  At least
> 160 people died on the island, including the 35 fatalities in a hotel
> struck by a landslide.
> 
> A major complication in the New Guinea event was that many of the villages
> were on a sand spit -- there was no escape.
> 
> The town of Seaside, Oregon faces a similar problem -- the bridges needed
> for escape will likely be destroyed by the quake which is expected sometime
> in the next hundred years.  Wide areas of the Northwest coast, from
> northern California to Vancouver Island, were inundated by the massive
> tsunamis generated by the estimated M9.2 quake in January of 1700.  The
> expected quake will likely range from M8.0 to 8.5.
> 
> Bob Fryer  -- on the Cascadia Subduction Zone
>

_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: Greg 
Subject: Re: Papua New Guinea tsunami
Date: Sun, 26 Jul 1998 11:22:07 -0700

barry lotz wrote:
 
> Bob,Greg
>    I think Hawaii have a similar warning system when a large event is

http://www.unesco.org/ioc/oceserv/itsu/itic.htm

The link I sent to the list is for the International Tsunami Information
Center (ITIC) is in Hawaii. I think there is also a U.S. only Tsunami
Warning Center in Hawaii. I found links for one in Alaska and one in
British Columbia. There was also something about Kamchatka, but I don't
remember. I wouldn't doubt that Japan has it's own as well. My guess is
they all coordinate with the international one. Not to sound too
insulting but there are lots of typos on the page and it hasn't been
updated since November 1996. 

Pacific Tsunami Warning Center
91-270 Fort Weaver Road
Ewa Beach, Oahu, HI 96706

International Tsunami Information Center
737 Bishop Street, Suite 2200
Honolulu, HI 96813-3213

,Greg

_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: Karl Cunningham 
Subject: Re: STM-8 drawings
Date: Sun, 26 Jul 1998 12:47:52 -0700

Sean-Thomas --

I downloaded the new drawings on your STM-8.  They look great!  To view
them, I saved the images to disk and printed them with LView (a shareware
graphics program).  Printed at 600dpi, there is very little loss in quality
and they are quite easily read.

Thank you for taking the time to make these drawings and making them
available to us.

Karl Cunningham
La Mesa, CA.
PSN Station #40
karlc@.......


At 08:17 PM 7/24/98 -0500, you wrote:
>I have finally posted the latest drawings of the hardware-
>store seismometer on the web site at:
>
>http://www.eas.slu.edu/People/STMorrissey/index.html
>
>under the "figures and drawings" page. The seismometer
>drawings are of two dimensions only; the overhead view
>can generally be deduced from the side view because of
>the natural symmetry of the design.


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: Ted Blank 
Subject: Re: [Fwd: Santa Cruz Seismic Instruction Software]
Date: Sun, 26 Jul 1998 18:22:41 -0700 (PDT)


I will speak to my son's science teacher.  When I mentioned it to her 
last year she was very excited about the idea.  Thanks for proposing to 
sponsor us.  



Ted Blank
San Jose, California

On Thu, 23 Jul 1998, Edward Cranswick wrote:

> 
> 
> --
> 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".
> 
> 
Jan-
	I thought that you, Steve, and Ted might do something, and I think that
I forwarded some kind of info to the PSN-L.  However, I was not really
connected with it myself, and I wasn't going to try to tell you guys
what you should do (what maybe I should have helped to do myself).  In
any case, the IRIS meeting does not get as much coverage as the AGU
meetin in San Francisco in December which Larry and Ted attended last
year with me.  So I think it would be a great idea to pursue the idea
that you and Ted talked about last year of having a bunch of students
submit a poster for the AGU meeting 6-10 December this year
. You guys can write the
abstract and prepare the poster and I, as an AGU member, can sponsor it
and get the USGS to pay for it. The abstract deadline for that is: 

	August 26, 1998		(Postal/express mail submissions)

        September 2, 1998	(Interactive Web Form submissions) 

	Because we only have about a month, please let me know ASAP what you
think and also CC a copy to me at  which what
I am trying to make my address for PSN-related activities.
-Edward

Jan Froom wrote:
> 
> It's a shame that we couldn't have gone to this conference, since I think
> Steve, Ted & I  are about the only ones in this area that are actually working
> with schools.... well Elementary, Middle & High.  I tried, and got a note from
> a lady in Arizona that forwarded my request to a lady in Santa Cruz....  but
> after that I got no answer.
> ---------------------- Forwarded by Jan Froom/San Jose/IBM on 07-22-98 11:26 AM
> ---------------------------
> 
> Ted Blank
> 07-21-98 01:13 PM
> To: Jan Froom/San Jose/IBM@IBMUS
> cc:
> From: Ted Blank/Santa Teresa/IBM @ IBMUS
> Subject: Re: Santa Cruz Seismic Instruction Software
> 
> I tried to get the information from Larry but it was all very vague.  Finally
> he called me the night before to say it was the next day but by that time I had
> other plans.  Oh well.
> 
> Regards, Ted
> DB2 Performance, IBM Santa Teresa Lab, San Jose, California
> 
> Ted Blank/Santa Teresa/IBM .....(from Notes)
> IBMUSM50(TED) .............................(from PROFS/VM)
> ted@.......... ..............................(from internet sites)
> STLVM6(BLANK) .............................(for LIST3820 files etc.)
> Tie: 8-543-3589    Ext:  (408) 463-3589   Fax:  (xxx-2614)

-- 
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: Peter 
Subject: Re: Papua New Guinea tsunami
Date: Sun, 26 Jul 1998 23:32:14 -0700

Here is a page that has a cheap warning device, I don't know if it would
work in some cases?

http://www.pacifier.com/~sunmanh/edd_tws.html

Pete Fleming


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Public Seismic Network Mailing List (PSN-L)


From: lahr@..................
Subject: Re: Papua New Guinea tsunami
Date: Mon, 27 Jul 1998 10:39:15 -0600 (MDT)

Pete,

I would say that the device is of no help!  Where the ball would fall, if indeed
the ball of the entire divice didn't land on the floor, would depend on the focal 
mechanism of the earthquake.  If the EQ is offshore and the first motion at the home is a 
compression, then the ground would move up and landward.  If the first motion was
a dilation, then the ground would move down and seaward.  Therefore, the direction
the ball falls would not give information about the location of the earthquake.

If I were located at sea level in a tectonically active area, I would head for high
ground right after feeling a strong earthquake.  It could be a false alarm, but
why take a chance?

JCLahr
################################## John C. Lahr
################################# Seismologist
################################ U.S. Geological Survey
############################### Geologic Hazards Team, MS966
############################## PO Box 25046
#############################/##############################
############################/###############################
Denver, Colorado 80225-0046 ################################
    Phone: (303) 273-8596 ##################################
     Fax: (303) 273-8600 ###################################
         lahr@........ #####################################
                http://giseis.alaska.edu/lahr
               http://lahr.org/john-jan


> Date: Sun, 26 Jul 1998 23:32:14 -0700
> From: Peter 
> 
> Here is a page that has a cheap warning device, I don't know if it would
> work in some cases?
> 
> http://www.pacifier.com/~sunmanh/edd_tws.html
> 
> Pete Fleming
> 
> 
> _____________________________________________________________________
> 


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Public Seismic Network Mailing List (PSN-L)


From: "Walt Williams" 
Subject: PSN-L: Papua New Guinea tsunami
Date: Mon, 27 Jul 1998 10:32:54 +0000

Hello Greg and All,

Recently presented on the 'Discovery Channel' was a three hour 
show about Tsunamis, their destructive power, warning systems, 
mechanical tsunami break-wall systems (Japan). Japan does have full 
time tsunami center. I did not view the beginning nor the end of the 
show. It was an excellent presentation. I am in the Los Angeles area, 
and the show was last month.

Walt Williams, 98.07.27 
=========================================================


------- Forwarded Message Follows -------
Date:          Sun, 26 Jul 1998 11:22:07 -0700
From:          Greg 
To:            PSN-L Mailing List 
Subject:       Re: Papua New Guinea tsunami
Reply-to:      PSN-L Mailing List 

barry lotz wrote:

> Bob,Greg
>    I think Hawaii have a similar warning system when a large event is

http://www.unesco.org/ioc/oceserv/itsu/itic.htm

The link I sent to the list is for the International Tsunami
Information Center (ITIC) is in Hawaii. I think there is also a U.S.
only Tsunami Warning Center in Hawaii. I found links for one in Alaska
and one in British Columbia. There was also something about Kamchatka,
but I don't remember. I wouldn't doubt that Japan has it's own as
well. My guess is they all coordinate with the international one. Not
to sound too insulting but there are lots of typos on the page and it
hasn't been updated since November 1996. 

Pacific Tsunami Warning Center
91-270 Fort Weaver Road
Ewa Beach, Oahu, HI 96706

International Tsunami Information Center
737 Bishop Street, Suite 2200
Honolulu, HI 96813-3213

,Greg

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From: Hubert Vroomen 
Subject: Re: period/mass etc of STM
Date: Mon, 27 Jul 1998 13:49:35 +0200

Dear Sean-Thomas and others,

I have been following the discussion around the development of the STM-8
with great interest. Altough not actively involved in real seismology
(neither as an amateur nor professional, yet), I am interested in its
aspects of precise instrument construction. I have been involved however,
for a very short period, in gravity measurement and the development of an
airborne gravimeter based on the GWR superconducting gravimeter.=20

(By the way, if someone happens to have some information or even a (copied)
handbook of a Askania/Bodenseewerke GSS2 or GSS-20 ship-borne gravimeter,
which she/he could make available to me, I would be much obliged. I have
such a piece of mechanical art here and besides a cruel electrical
schematic I have almost no substantial information on the beast (if someone
is interested, I can give more information in a later post).)

But now for the reason of this post. I have been thinking about the
possibilities of recentering the STM-8 beam, as the method you proposed,
using a thread with a small weight, seems to me not the most elegant way. I
would think, that a method that is not using some moving parts on the beam
would be preferred above a method which is. Your post on the adjustment of
the period brought me the following idea:

If you could change the moment of the spring-force, which you are doing
when changing the point of attachment of the spring along the beam, one
would be able to recenter. To even improve the elegance of the system, one
could try to change the position of the attachment to the BASE, instead of
changing its BEAM-position. Doing this with a slow, gentle motion would
result in a (possible) elegant way of recentering.

I have thought of using a piece of aluminium wire or rod for this, and
using a controlled current through it to control its temperature and
therewith the length of the part, which can be used (either direct or via a
lever-system) to change the base-position of the spring. But after some
after-tought :-), I came to the conclusion that using a
differential-temperature actuator in a temperature sensible system like a
seismometer would not be the smartest idea, but the basic priciple stands,
and one could try to use a small electric motor to change the position as
well.

In fact, one could also use the spring itself as an actuator as well,
running some fine heating wires along the spring-surface, but I could
imagine that the resulting differential movement of these wires along the
surface could result in substantial damping, which is not good off-course.

I must admit, that the overall design and concept of the STM-8 amazes me
because of its simple and natural beauty, and putting an electrical motor
on the beam seems to me like putting a ski-rack on a Porsche (or, for you
US-guys, on a Camaro). That is the reason I came up with this new
recentering concept. I have no proof of it being better (or worse), just my
intuition as a mechanical engineer and precision instrument freak. I have a
lot of other potential ideas in which to improve the STM-design in detail,
but the basic thought behind it is just marvelous and could really bring
amateur-seismology a lot further.

Just some of my neurons that didn't want to sit still,

Hubert


Ir. Hubert Vroomen
Heinz Nixdorf Institut
Universit=E4t-GH Paderborn
Paderborn, Germany

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From: lahr@..................
Subject: Re: PNG Tsunami
Date: Mon, 27 Jul 1998 12:43:59 -0600 (MDT)

Speaking of the PNG disaster, I just received this Email message and decided
to send a small check. 

JCLahr

Better to light a candle than to curse the darkness.

> ===============$$$$$$$$$$$$$$$$$===============###############========@@@@
> 
> Date: Mon, 27 Jul 1998 11:35:15 -0400
> From: Rick Wunderman 
> Subject: [NAT-DSR:452] Papua New Guinea: Tsunami [PNG Embassy: 23-Jul-98]
> To: jon.fink@.......
> 
> >Subject: [NAT-DSR:452] Papua New Guinea: Tsunami [PNG Embassy: 23-Jul-98]
> >
> >Embassy of Papua New Guinea
> >Washington, DC
> >Disaster Relief Fund Appeal
> >23 July 1998
> >
> >
> >Dear Friends/Wantoks/Relatives of Papua New Guinea
> >
> >You would have already been informed through the international media
> >on the tsunami (tidal wave) which brought catastrophe upon three
> >Aitape sub-district villages in the northwestern part of Papua New
> >Guinea on the night of Friday, July 17, 1998.  The Embassy of Papua
> >New Guinea staff and their families are saddened by this latest
> >tragedy and are appealing for combined prayers and support for those
> >country-folks affected.
> >
> >
> >GENERAL BACKGROUND
> >
> >The tsunami, in three successions of waves towering approximately 30
> >feet (10 meters), resulted from a 7.0 magnitude shallow underwater
> >earthquake 18 miles (30 Kilometers) off the coast.  The three
> >villages, Arop, Nimas, and Waropu were completely destroyed whilst
> >neighboring Sissano, Malol, Aitape, and seven others received
> >extensive damages.
> >
> >Unofficial death toll stands at approximately 700 with possible
> >figures reaching between 2500 and 3000.  The three devastated
> >villages have a population of over 8000 inhabitants and thus far 6000
> >are unaccounted for. Reports received indicated that the elderly and
> >children were mostly killed in the disaster.
> >
> >The tsunami is the latest of a series of natural disasters striking
> >Papua New Guinea in the last three and a half years.  The volcano
> >eruption in Rabaul, cyclone Justin's destruction in the Milne Bay
> >area, and the El Nino-induced drought in most parts of the country,
> >have caused a horrendous burden on the Government and the people of
> >Papua New Guinea.
> >
> >
> >CURRENT RELIEF OPERATIONS
> >
> >At present, the Government, with assistance from the Australian and
> >New Zealand Defence forces, are working around the clock to bring
> >relief supplies and medical attention to the affected areas.  Relief
> >efforts are currently at phases one and two of the post-disaster
> >exercise.
> >
> >Phase one efforts include identifying the missing, recovering bodies,
> >cremation or burial, and evacuating survivors to medical centers.
> >Phase two will be to deal with the traumatized survivors and
> >relatives, and to sanitize the affected areas from diseases resulting
> >from the tsunami.  Concurrent on- site medical attention and
> >evacuation of survivors and villagers from nearby are part of the
> >phase two exercise.
> >
> >
> >EMBASSY OF PAPUA NEW GUINEA RELIEF FUND
> >
> >The Embassy is embarking, through this letter, to announce its relief
> >assistance efforts from the Americas by setting up a disaster relief
> >account to solicit donations for the people of Aitape sub-district
> >who are currently in distress.  The funds will assist in phase three
> >of the relief exercise which will include resettling of survivors
> >into new village dwellings and assisting them rebuild their lives.
> >Donations should be made to:
> >
> >               "Aitape Disaster Relief Fund"
> >               The Embassy of Papua New Guinea
> >               1615 New Hampshire Avenue, N.W.
> >               Suite 300
> >               Washington D.C., 20009
> >               United States of America
> >
> >
> >Due to the Embassy's incapacity to receive and handle volumes of
> >relief materials and supplies, it is requesting individual and group
> >donors to channel their items through legitimate or qualified
> >international organizations such as the Red Cross (in the U.S. and
> >Canada), Counterpart International Inc., Doctors Without Borders,
> >Habitat for Humanity, Oxfam America, Project Hope, and others.  The
> >materials and supplies referred to include shelter, medical supplies,
> >clothing, sanitary water, and logistic systems.  Specialists such as
> >doctors, trauma counselors, and other humanitarian-related agencies
> >willing to provide services, should also seek programs that are
> >sponsored by these organizations.
> >
> >
> >CONTACTS FOR DISASTER RELIEF EFFORTS
> >
> >The Embassy of Papua New Guinea's contacts on the relief exercise is
> >Mr Graham Michael, Counsellor, and Ms. Barbara Age, Second Secretary.
> >They will be available to facilitate any enquiries on relief efforts
> >and donations, provide media guidance on the latest, and co-ordinate
> >with international disaster relief organizations on programs
> >associated with the Aitape disaster. They can be reached on
> >Ph: 202 745 3680, Fax: 202 745 3679, or through
> >E-Mail: kunduwash@.......
> >
> >The Embassy will keep you updated should further information becomes
> >available.
> >
> >
> >
> >H.E. Nagora Y. Bogan, KBE
> >Ambassador
> >
> >
> >
> >
> >distributed by
> >- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> >Volunteers in Technical Assistance
> >Disaster Information Center                   lists: listproc@........
> >                                                     sitreps   nat-dsr
> >      web: www.vita.org                              appeal    fireline
> >- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> >comments/suggestions/requests to incident@........
> ###########################################################################
> 


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From: Ashley Neal Hornbeck 
Subject: What is the destructive range of an earthquake?
Date: Mon, 27 Jul 1998 15:43:42 -0500

Hello All,

I'm one of the silent reader of this list.  I've lived in Texas my entire
life.  Because I have practically no experience with earthquakes I have a
question.

Is there a rule-of-thumb attenuation equation for earthquakes?

In other words:
If I'm x miles away from the epicenter of M7.0.
That would be equivalent to being directly above the epicenter of a M y.
Where:
 x is distance
 y is magnitude

While this may not be the proper way of describing the force at some
distance, x, away from the epicenter I believe you can understand my question.

Would someone mind helping with this?

Thanks,
Ash

 -----------------------------------------------
| Ashley Neal Hornbeck - Hornbeck@............. |
 -----------------------------------------------
| iiSys Corporation                             |
| 12777 Jones Road, Suite 195                   |
| Houston, TX  77070                            |
 -----------------------------------------------
| (281) 894 1674                                |
 -----------------------------------------------

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From: Edward Cranswick 
Subject: Re: Include PSN in seismic network survey?
Date: Mon, 27 Jul 1998 17:14:10 -0600

Steve-
    I agree with you, I admire your energy, and by coincidence, I received
another request for this information today from Steve Malone (see below).  I
think it would be a good idea to include the PSN info in the CNSS directory as
you and he both suggest because it will give the PSN more access to the world,
and the vice versa; that I think is one of the main rationales for the PSN in
the first place.
-Edward

*********************************************************************
[Steve Malone wrote:]

        Also, on a different subject, since I know you are interested and
involved in the Peoples Seismograph Network I have a question.  I have
been tasked with doing an inventory of seismic networks in the US and am
getting a response from most of the regional networks (ie members of the
CNSS).  The `PSN' has never been an actual part of the CNSS since it is a
pretty ad hoc group with no central authority (as it should).  However,
for this inventory (and maybe just to increase its visability it might be
nice to include stations form the PSN in what I am doing.  You may find a
descritpion of what I need on the WEB at:
        http://www.cnss.org/NETS/request.survey.txt

Any ideas you might have on how I could do this, please let me know.


        Steve Malone                    E-mail: steve@......................
        Geophysics Program              Phone: (206) 685-3811
        University of Washington        FAX: (206)543-0489
        Box 351650                      Office: ATG-226
        Seattle, WA 98195       http://www.geophys.washington.edu

*********************************************************************

Steve Hammond wrote:

> I think it is important for use to be included in this listing. We
> contribute to the international record and have been contributing for
> eight years. I took the liberty of going to Dave’s WEB site and
> downloading the text list of all the stations. We have the data together
> it just needs to be formatted. Does anybody feel we should not submit
> this to the Office of CNSS?If not I need just a little help to assemble
> Dave’s New Zealand station PSN station Site listing into the proper
> format. Can you look at this URL
>
> http://www.iris.washington.edu/manuals/acrobat/SEED_A_only.pdf
>
> and define the shackle-ford-gundersen, Lehman, geophone <10 sec
> response. I want to make sure I get it right-- And anybody with good
> eye’s might look over our station list and add other’s like the AS-1.
> Please look over these items and contribute. Also, if you don’t want to
> be included please tell me.
>
> ----Hey Larry! ---- how much data do we have on-line and off-line now? I
> have 500MB or so on CD-ROM from the original BBS network.
>
> The deadline is the end of July folks--
>
> Regards, Steve Hammond   PSN San Jose, California
>
> Edward Cranswick wrote:
> >
> > PSN-
> >     As usual, I am passing this on a bit late, but I am still trying to
> > unravel the enigmatic link or lack thereof I have with the PSN-L.  So I
> > am sending this out to see our response.
> > -Edward
> >
> > ********************************************************************
> > Subject:
> >          Request for network information
> >    Date:
> >          Wed, 8 Jul 1998 10:23:28 -0700 (PDT)
> >    From:
> >          Steve Malone 
> >
> > I have sent e-mail to all of the official CNSS network representatives
> > and
> > alternates regarding the need for information for an "Assessment of
> > Seismic Monitoring in the US" and a contribution to an IASPEI
> > publication.
> > If anyone associated with a regional network who should have gotten
> > this notice but did not you may find it posted on the WEB at URL:
> >
> >         http://www.cnss.org/NETS/request.survey.txt
> >
> > Please try to make sure that any seismic network you are associated with
> >
> > will be responding to this request.
> >
> >         Thanks,
> >
> >         Steve Malone                    E-mail:
> > steve@......................
> >         Geophysics Program              Phone: (206) 685-3811
> >         University of Washington        FAX: (206)543-0489
> >         Box 351650                      Office: ATG-226
> >         Seattle, WA 98195       http://www.geophys.washington.edu
> >
> > --
> > 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)
>
> 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".




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From: S-T Morrissey 
Subject: centering and temp comp of STM seis
Date: Mon, 27 Jul 1998 18:27:59 -0500 (CDT)

Hubert,
Thanks for your observations about the recentering of the STM-8
vertical seis. I do believe that using a small DC (9volt,5 ma)
gearmotor (2 RPM) (Edmund Scientific number 41331, $25) to
turn a thin threaded rod (6-32) attached to its output shaft 
to translate a small mass (10grams, with a larger 10-32 hole)
in parallel with the boom is going to be hard to beat for elegance
and simplicity. I wouldn't worry about the asthetics of it any
more than I worried about the ski rack on the back of my old
'70 Corvette: one has to do what has to be done. And the motor
and shaft are completely passive when not in use. A full scale
recentering takes about 5 minutes, introducing about 50 milliwatts
of heat in the motor case, which I do not think I can later see
in the output. I guess I need to get a photo of it to the web site.

The motor is just about balanced at its mounting flange with the 
weight of the 10 cm stainless steel or brass shaft extension ,
so mounting it to a corner of the aluminum angle at the moving side 
of the main hinges only slightly increases the moment of the boom.
This reduces the effective "reduced pendulum" length ( where not all 
the mass is at the end as in an ideal pendulum) which slightly 
shortens the mechanical period. Since this is a VBB fedback
system, this slightly affects the damping term.  However, the effect 
IS slight, and the change is not observable above the noise in the 
output of a step calibration with the sensor operating at 90 seconds. 

And the adjustment of the period itself is really not critical,
with 6 to 10 seconds being a convenient value. Longer mechanical periods
are more unstable, which adds to the thermal problem of the large
leaf spring, which currently contributes about 200 microns of 
displacement (at the VRDT) per degree C with the feedback off. 
This is about ten times the effect calculated from the thermal
coefficients of the hinge support, VRDT and vane support, etc.

This temperature effect of the leaf spring is still a serious 
problem that needs to be solved in an elegant way. An additional 
complexity is that the spring has what might be called a negative 
thermal coefficient. Ie, it gets stiffer with a temperature decrease, 
which raises the boom.  This would suggest that some thermo-elastic 
elememt that contracts when cooled could be used to compensate the 
expansion of the leaf spring. I am currently experimenting with
a very fine coil spring (100 turns wound at 5mm diameter of #36 drawn
copper) installed from the boom to the base. It is too early to
determine its effectiveness. 

The only really successful thermal compensation has been electronic,
 using the LM35 thermometer chip and the 25-turn auxillary coil
 at the magnet. This can contribute noise in the passband, so it
 is low-pass filtered at 5000 seconds. It is another complication
 though, with additional electronics, and not the "set it and 
 forget it" compensation that I would prefer.

 Regards,
 Sean-Thomas


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From: meredith lamb 
Subject: More surplus geophones & etc.
Date: Mon, 27 Jul 1998 18:07:52 -0600

Hi all,

My brother Robert (Bob) has alerted me to a new geophone source
(I think,... besides Gateway & Startronics in recent past).

http://www.allcorp.com/

The web site seems to cover alot of territory over other surplus
sources.  Magnets (afew 1/4" thick variety neo....cheap
compared to alot of other sources...if you don't have any, this
is the place to buy).  Looks like 2 pole & likely 4 pole varietys
per catalog. Relays etc, etc., 96 pages catalog which
you can download via free acrobat reader (3.191 meg for catalog).
Or you can request a mail copy per site.

Anyway...the geophone (pg 96), cat GP-1, $8.00 plus minimum
of $5.00 shipping and handling; doesn't go into details, nor is
there any indication they are all the same model (presumed).
LED indicator circuit schematic enclosed, which Bob says works.
Foreign purchase ok, if drawn on U.S. bank...see details.

Bobs purchase geophone was a 10hz, 600 ohm, which he
claims are much more sensitive than the Startronics (Arizona) model
(14hz) ...roughly by ~8X signal.  Size, 1.6" height X 1.2" diameter.
Bob is a retired electronics engineer.

Visit the web site for more info.  Los Angeles & Van Nuys, California
stores.

I think this surplus source has been around for quite a number of years,
but I've never bought anything from them myself.  Bob has several
times, so I presume they are OK.

Am no geophone user myself, strictly teleseimometrist....unless I
lived in California, or was visiting Yellowstone National Park-ha.

Meredith Lamb


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From: S-T Morrissey 
Subject: eq magnitude range
Date: Mon, 27 Jul 1998 19:17:43 -0500 (CDT)

Ash,

What you feel from a given quake of a given size depends on
what part of the country you live in and what your local geology
consists of. There are really no exact formulas, and the matter
is complicated by the use of two (in general) earthquake scales.

The Richter scale indicates the total energy released by an event,
and generally everyone gets the same magnitude from their seismic
data regardless of their distance from the quake (unless, of course,
they are in dire need of funding, which moves the quake closer to
their area of study and increases the magnitude.) Magnitudes do not
relate directly to what is felt because a deep earthquake will be
felt weakly over a larger area that a stronger shallow event. Several
years ago there was a large (7.0+)  quake 600 km deep below Bolivia
that was felt from Panama to Buenos Aires, but did little damage.
Magnitudes are listed as arabic numbers with a decimal point, eg 5.5.

The Mercalli intensity scale relates what physically happens in
the epicenter area, from a MMI of being sensed by sensitives to
a MMXII being total devastation. It is pretty subjective, and needs
input of local geology, what the local population has recently
inhaled, etc, to relate it to the Richter magnitude.
(There is a listing of it on our Earthquake Center web site,
//www.eas.slu.edu/Earthquake_Center/mercalli.html).
Intensities are listed as Roman numerals, with no decimal point.

Here in the USA, it generally takes a (Richter) magnitude 3.0 to
be felt, and a 5.0 to throw things off shelves in the epicentral area,
a 6.0 to crack buildings and bridges, and a 7.0 to throw them down.

But if you are not at the epicenter, then local and regional geology
will control the Mercalli intensity you feel. Here in the midwest, a
magnitude 5 can be felt over 100 km away, but in California, in the 
mountainous regions, it may only be felt 10 km away , and even less
near the freeways. But often the most destruction (higher intensity)
is in soft alluvial valleys, which amplify the ground motion, as in
Mexico city,  and the areas near the San Francisco bay in the Loma 
Prieta quake several years ago. In the Aleutians, we could feel
magnitude 4.0 events 50 km away because of the solid volcanics.

Regards,
Sean-Thomas

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From: Fred S 
Subject: Re: Papua New Guinea tsunami
Date: Mon, 27 Jul 1998 17:40:00 -0700

Pete,  This reminds me of a device I saw in a history book used in China
around 1200AD.  A ball would drop in the oppisite direction. Pretty cool
idea for such a long time ago.

-- 
Gravity:  It's not just a good idea.  It's the LAW !

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From: barry lotz 
Subject: Re: centering and temp comp of STM seis
Date: Mon, 27 Jul 1998 16:58:04 -0700

Sean Thomas
 $0.02
   It has been my belief that besides the possible affect of temperature
on the spring length/stiffness,  the main reason that the beam moved up
was that the air is more dense at lower temperatures. Since the bouyancy
force is the weight of the medium displaced there is a larger bouyancy
force at lower temperatures.

                                      Barry

PS I found the approximate volume of my sensor using the unit weight of
aluminum. I then calculated the uplift(air density change) for a 10
degree temperature change. For a given temperature change I measured the
voltage change(drift)of my sensor. It agreed  reasonably well with the
vts/gm calibration factor I had obtained previously.


>S-T Morrissey wrote:
> ....
> This temperature effect of the leaf spring is still a serious
> problem that needs to be solved in an elegant way. An additional
> complexity is that the spring has what might be called a negative
> thermal coefficient. Ie, it gets stiffer with a temperature decrease,
> which raises the boom.

_____________________________________________________________________

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From: "Walt Williams" 
Subject: PSN-L: (Fwd) More surplus geophones & etc.
Date: Mon, 27 Jul 1998 18:30:43 +0000

Hi Meredith & All,

I recently bought several Geosource MD-81, 10 Hz geophones from the
Van Nuys, California, USA, store. They are packaged exactly the same
as the Gateway supplier, but are slightly less expensive. Mostly
same type. They have same diagram and a little perfboard with a LM393
quad comparator and some resistors. You solder together to make
simple circuit with red LED.

I put my Tek-465B with x1 probe, 5 mv channel setting directly on
geophone pins, place on rug (simple low-pass filter :-), lots of 60
Hz, but works pretty good! I can see cars and trucks passing maybe
60 meters from house. Can see cat walking in kitchen, making din din
run -- no amplifier, surprisingly sensitive! One of the nice folks 
(Roger Sorenson) on PSN sent me TurboCAD layout for geophone amp he 
built, I have hacked that up and made a simple test circuit, works 
well. This is very interesting, lots of good ways to spend boring 
nights!

Cheers,

Walt Williams, 98.07.27
dfheli@..............

------- Forwarded Message Follows -------
Date:          Mon, 27 Jul 1998 18:07:52 -0600
From:          meredith lamb 
To:            psn-l mailing list 
Subject:       More surplus geophones & etc.
Reply-to:      PSN-L Mailing List 

Hi all,

My brother Robert (Bob) has alerted me to a new geophone source
(I think,... besides Gateway & Startronics in recent past).

http://www.allcorp.com/

The web site seems to cover alot of territory over other surplus
sources.  Magnets (afew 1/4" thick variety neo....cheap
compared to alot of other sources...if you don't have any, this
is the place to buy).  Looks like 2 pole & likely 4 pole varietys per
catalog. Relays etc, etc., 96 pages catalog which you can download via
free acrobat reader (3.191 meg for catalog). Or you can request a mail
copy per site.

Anyway...the geophone (pg 96), cat GP-1, $8.00 plus minimum
of $5.00 shipping and handling; doesn't go into details, nor is
there any indication they are all the same model (presumed).
LED indicator circuit schematic enclosed, which Bob says works.
Foreign purchase ok, if drawn on U.S. bank...see details.

Bobs purchase geophone was a 10hz, 600 ohm, which he
claims are much more sensitive than the Startronics (Arizona) model
(14hz) ...roughly by ~8X signal.  Size, 1.6" height X 1.2" diameter.
Bob is a retired electronics engineer.

Visit the web site for more info.  Los Angeles & Van Nuys, California
stores.

I think this surplus source has been around for quite a number of
years, but I've never bought anything from them myself.  Bob has
several times, so I presume they are OK.

Am no geophone user myself, strictly teleseimometrist....unless I
lived in California, or was visiting Yellowstone National Park-ha.

Meredith Lamb


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From: meredith lamb 
Subject: MEK to remove glue
Date: Mon, 27 Jul 1998 20:44:54 -0600

Hi All,

Bob Lamb recently suggested using MEK solvent to assist in
dissolving glue holding magnets and metal washers from speakers;
and of course for other parts desired.  It will remove paint and
ruin plastic of course.

Bob Lamb:  "Over the years I have had alot of success with "MEK"
solvent - especially leaving things for a day or so; even softens some
epoxy-like cements.  Very volatile bad stuff, so its a strictly a
outdoors use item, with a breeze in the right direction."  Keep out
of reach of children, pets, etc.   "MEK, is the same ingredient in
PVC cement."

The original goal was too remove a ring or donut ferrite magnet
from a speaker magnet assembly, for possible further machining.
The item I tried it with was a broken Radio Shack speaker,
originally for the STM-8 vertical seismometer.  After 3 days of
soaking, it was apparent that the fluid was not penetrating very
well, as it still could not be removed.  It may work if its allowed
to soak for a much longer period of indeterminate time.  The
visual side glue was softened within hours and easily was removed.
No harm was done to the steel or ferrite by the chemical.

Probably not the route to go, if one is in a hurry.

Meredith Lamb









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From: Pinpoint 
Subject: Re: MEK to remove glue
Date: Mon, 27 Jul 1998 21:13:32 -0700


>Bob Lamb recently suggested using MEK solvent to assist in
>dissolving glue holding magnets and metal washers from speakers;
>and of course for other parts desired.  It will remove paint and
>ruin plastic of course.

Acetone works well also and has same problems.....
   I worked with 50-50 acetone water in a fine spray mist for 2 years
inside of a very closed environment. The results was major brain and liver
damage and to this day I receive disability because of it...Watch out for
solvents!


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From: Fred S 
Subject: Re: period/mass etc of STM
Date: Mon, 27 Jul 1998 23:56:19 -0700

I like this idea Hubert. There is a material called Nitinol wire might
work well for this. I think Edmund Sceintific and Mondo Electronics both
carry it. It has a very predictable contraction with application of
current. They also have spring type actuators Another good idea might be
some kind of insulation such as teflon tubing to reduce the effect of
air currents. I have never used the stuff but was thinking about
designing a simple shaker table for calibrating sensors.  Anyone else
have any experience with this material ?

Fred  
-- 
Gravity:  It's not just a good idea.  It's the LAW !

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From: Hubert Vroomen 
Subject: Re: centering and temp comp of STM seis/ bouyancy effect
Date: Wed, 29 Jul 1998 00:33:02 +0200

Hello Sean-Thomas and others,

regarding my idea of centering through spring movement:

you wrote
>and simplicity. I wouldn't worry about the asthetics of it any
>more than I worried about the ski rack on the back of my old
>'70 Corvette: one has to do what has to be done. And the motor

whoa, a corvette, cool (drool). Sorry, had to say this, I know it is of
topic. But still, that ski-rack bothers me :-).

I was wondering, as Barry Lotz told in another mail of his calculations of
the bouyancy-effect, if you could give some more precise numbers of this
"negative temperature spring effect". If I remember well, you did some
experiments with pill-jars to compensate for a bouyancy effect, wasn't it.
I do not remember whether it was a succes or not, just curious to see if
bouyancy might give a rather large or small error-contribution. I mean, it
would not only help in temperature correction, but in pressure correction
as well.

thanks in advance for a interesting discussion,

Hubert

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From: Hubert Vroomen 
Subject: Re: period/mass etc of STM/ Nitinol actuators
Date: Wed, 29 Jul 1998 00:23:05 +0200

dear Fred and others,

the use of Nitinol and other so-called SMA (for shape-memory-alloys) is not
new. It has been done for about twenty years (if my memory serves me well)
and is also known under the name of artificial muscles. In fact, you can
find some coincidence with the behaviour of real muscles.

Regarding your idea of building a shaker table with SMA-actuators, it
definitely depends on the frequency range you are planning to use. SMA is
not good at higher frequencies (don't ask for a number, my intuition says
definitely bad above 1 Hz. or so), especially because of the thermal
problems concidering rapid heating and cooling. It is just pretty difficult
to heat a wire over a temperature range of several degrees with a frequency
of more then a several tenth's of a Herz, and it is even more difficult to
cool it at a frequency like that. 

In my, humble, opinion, I would go for a simple crank with a fixed
amplitude if building a shaker table. Just by variing the rotational speed
of the crank you change the frequency of vabration, and making a crank turn
very slow is not so difficult (stepping motor, DC motor with proper
gearing). To determing the speed at higher frequency you can use a
stroboscope or an electronic speed counter. For lower speeds, just mount a
piece of cardboard on the crank that "flaps" agains some fixed structure
and count the number of flaps during a certain time.

Someone on thit list has build a shaker table for a school project using an
electrical hand-drill, if I remember well. I think that it was Bob Hammond
in Alaska, but I am not sure (have difficulties with all those Bob's and
Hammonds on the list, to much german beer I suppose :-)).

Please don't hessitate to ask if you have any more questions.

Hubert

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From: S-T Morrissey 
Subject: mass buoyancy
Date: Tue, 28 Jul 1998 18:46:58 -0500 (CDT)

Barry,

I saw but cannot find your previous calculations for the buoyancy change
of the mass due to air density change due to air temperature change.

In general, we do not see this effect with the commercial VBB
seismometers; their temperature behavior is the same whether they
are evacuated or not. This seems to also be true for the "sealed"
sensors such as the STS-2 and the Guralp series, where any change
in temperature would actually change the density and consequently
the pressure of the air contained in the enclosure.

So I looked into the physics involved. Since density r falls out of the
ideal gas law PV = NkT, (P = pressure, V = volume, N = moles, k = constant,)
and r = N/V = P/kT, where T is the temperature in degrees Kelvin.
A 1 degree C change is actually a change from 298 to 299 deg. K (at 20
deg. C), or a change of about 0,336% in the density. Since the density of
air (at 20 deg C> )is 1.2047 MILLIgrams / cm^3. a change of 0.336% 
is 0.00404 milligrams.
When this is multiplied by the volume of the mass of the STM seis 
(about 50 cm^3), the buoyancy force is 0.202 milligrams. This is about
one-thousandth of the change in mass that is needed to correct the
leaf spring expansion for a 1 degree C temperature change.

Over a larger range of 10 to 20 deg. C (which my prototypes will
not operate over), the densities of air at STP can be found in the 
CRC handbook and are 1.2472 and 1.2047 mg/cm^3 at each temperature.
The difference is 0.0425 mg/cm^3, or a buoyancy of the mass of 2.125
milligrams. Again, this is a very small number compared to the mass
adjustment needed.

While we are discussing buoyancy problems, the CRC tables show an air
density change from 760 to 770 mm (hg) of 0.0159 milligrams/cm^3, or a
buoyancy force of about 0.0604 milligrams/millibar pressure change on
a mass of 50 cm^3 (which is why we should use lead on vertical sensors). 
This is the major noise source we have to deal with from the vertical 
sensor, assuming that good thermal insulation will keep the period 
of the thermal noise well out of our data passband.

Regards,
Sean-Thomas

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From: "Charles R. Patton" 
Subject: Re: period/mass etc of STM/ Nitinol actuators
Date: Tue, 28 Jul 1998 17:00:10 -0700

Nitinol, aka "muscle wire"; shape memory alloys; Dynalloy; Flexinol,
Titinol;  has some very nice characteristics including work-density
(being capable of large amounts of work vs volume but unfortunately it
would probably be unsuitable for this application.  The main drawback is
that it is not linear.  There is almost no change until it hits its
phase transition temperature, whereupon it goes through a large change
in strain strength (getting larger with increase of temperature)
together with significant hysteresis.  Typical numbers for Flexinol are
3% change in length from about 68 to 75 degrees Centigrade and then
returning through that 3% from 50 to 41 degrees Centigrade. Over the
whole 25 to 80 degree range it went through about a 5% change.  Note the
comment about strain strength =96 in order to use it to its best ability
it has to work against a preload such as a spring.  So in order to use
this you would have to preheat the wire to the transition range and hold
it there while controlling it.  That along with significant hysteresis
would make the control tough.

I still think that maybe the earlier post I made about controlling the
temperature of the spring itself might be the easiest, anyway just a
note to the discussion.

Charles R. Patton
Please change email to:  charles.r.patton@........

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From: Hubert Vroomen 
Subject: Re: mass buoyancy
Date: Wed, 29 Jul 1998 02:48:50 +0200

Hello Sean-Thomas and others,

I just did not completely understand the following part:

>In general, we do not see this effect with the commercial VBB
>seismometers; their temperature behavior is the same whether they
>are evacuated or not. This seems to also be true for the "sealed"
>sensors such as the STS-2 and the Guralp series, where any change
>in temperature would actually change the density and consequently
>the pressure of the air contained in the enclosure.

In my opinion, in a sealed container the mass of the enclosed air will not
change. So, a temperature change will result in a pressure change, but not
(in my opinion) in a change of density. The only reason I can imagine some
effect like this (in a sealed container) would be if you account for the
flexure or thermal contraction/elongation of the container, thereby
changing its inner volume. But because the thermal coefficients of air and
metals a different by several orders of magnitude this last term should not
be very important. In my feeling, only a changing density of the air inside
will result in a changing bouyancy, so this might be a reason for the fact
you do not see this effect in sealed seismometers.

But, to be honest, I have not done any calculations on this, so I might as
well be on the wrong side of the track.

>While we are discussing buoyancy problems, the CRC tables show an air
>density change from 760 to 770 mm (hg) of 0.0159 milligrams/cm^3, or a
>buoyancy force of about 0.0604 milligrams/millibar pressure change on
>a mass of 50 cm^3 (which is why we should use lead on vertical sensors). 
>This is the major noise source we have to deal with from the vertical 
>sensor, assuming that good thermal insulation will keep the period 
>of the thermal noise well out of our data passband.

this was the reason of your pill-jar experiment, wasn't it. Just a
question, can you separate between pressure and temperature effects? Here
in Europe (should be the same in the US) high pressure is often connected
to high temperature (and less rain, which makes correcting gravity
measurements a very interesting hobby :-)). I mean, do you see some diurnal
effect because of temperature, independent of the pressure-signal.

regards,

Hubert

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From: Hubert Vroomen 
Subject: Re: period/mass etc of STM/ Nitinol actuators
Date: Wed, 29 Jul 1998 02:34:57 +0200

Hello Charles and others,

my post on this subject was meant to be as a bit of information on Nitinol.
I totally agree with your analysis of its behaviour, that was one of the
reasons I discouraged it for the use in a shake-table. I think however,
that a non-SMA material with linear temperature behaviour (like brass, or
aluminium or simple steel) could be a nice actuator for large forces over
small strokes. And the fact that it is easily controlled via electric
current makes it even more interesting.

I just have some bad feelings with the usage of a heated part in a
seismometer, as we all are trying to keep these instruments on a as stable
temperature as possible. This would be indeed a pro for temperature
controlling of the spring. But, if you start controllng the
spring-temperature, it is not far away from controlling the temperature of
the whole instrument's enclosure, which has the added benefit of reducing
differential temperature effect because of different materials used in the
construction.

My idea of using the spring as an temperature-actuator is nearly the same
as your idea of controlling its temperature, but with the added benefit
that not only temperature might be controlled, but also (perhaps)
air-density/bouyancy effects.

It stays interesting this way, and somehow, a better world will result from
this :-)

Hubert


PS. Pardon my irony, just am finishing my PhD.-thesis and not much else
besides this list is giving me reason to smile these days, so pardon again.


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From: S-T Morrissey 
Subject: Re: centering and temp comp of STM seis/ bouyancy effect
Date: Tue, 28 Jul 1998 19:57:53 -0500 (CDT)

Hubert,
The old corvette has been parked in what has become the "seismometer
shop" since 1978 when the 4-piston brake calipers all started to
leak (bad castings) and I didn't have $1k per to replace them, and
I was spenting all my summers in Alaska. So how does one "antique" 
a corvette: park it in a garage and bury it with interesting "stuff";
we can still get in the drivers' door to play Gordon Lightfoot on 
the 8-track.

Re the seis barometric compensation with sealed pill jars installed
on the back side of the hinges: again, an experiment with an 
indefinite result. It seemed to help, but not notably; I suspect 
that they were actually flexing (plastic caps) with small changes 
of pressure. And figuring the correct volume*moment wrt. the boom
and the seis mass was an ambiguous endeavor.  I have thought of 
trying a copper toilet tank float if a real lightweight could be 
found. Or even some very low density but impervious solid.

In the mean time, the terraraium awaits being fitted out as a
pressure containment; not to be evacuated, but just to lengthen
the pressure time constant to several hours. I am working on a
way to pass the support of the seis through the glass bottom to
the pier in such a way that pressure flexing of the bottom does
not move the seis vertically. The other problem is a tight seal:
a small pinhole leak will breathe and blow the mass around.

The other idea is to shrink the design by at least 1/2 so it will
fit inside a large old fashioned pressure canner (Sears sells them).
They are cast aluminum and will hold a vacuum.

Regarding the leaf spring behavior of getting stiffer and extending
as the temperature decreases: I have no numbers on it, since the
effect in the seis depends on the mechanical period. I do observe
that the 4-second unit needs about a 1 cm shift (near the center of 
the boom) of the 10-gram trim mass to overcome a 1 deg. C temperature
change. The motor driven weight of 20 grams needs about 10 turns
(at 32tpi) to compensate for about half the temperature range, 
which causes a 7-volt offset of the mass position output, or 
about 200 microns with the feedback turned off. I need to modify
the 4-second (BETA) unit with the period adjustment feature of the
Gamma units to study this effect at longer periods. It may make
matters worse. Longer mechanical periods of a VBB fedback system
allow a better defined response, but are not necessary unless one
wants an extremely long period response. I have found that the VBB
period can be more than 20 times the mechanical period.

regards,
Sean-Thomas

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From: S-T Morrissey 
Subject: aquarium heater?
Date: Tue, 28 Jul 1998 20:08:01 -0500 (CDT)

Hubert,
I forgot to mention the plan C for temperature: to put an
aquarium heater in a large (liter+) jar of water inside the
seis case. They control within a degree F, and the jar of
water would average out the cycling of the heater. Maaybe
the heater can be broken into to refine its sensitivity.

I should do this on the prototype, because the 1000 second high
pass to the old drum recorder allows some DC drift through, so
the traces crowd or spread apart as the mass wanders around
over periods of hours or more.
 
Regards,
Sean-thomas

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From: S-T Morrissey 
Subject: Re: mass buoyancy
Date: Tue, 28 Jul 1998 20:35:27 -0500 (CDT)

Hubert,

I said it wrong about the sealed containers; you are right.
The density (mass per volume) cannot change because the mass
of air is held constant, except for the (probable) flexing
you noted. The pressure will change with temperature per 
the gas law.

Regarding diurnal pressure/temperature/tides/etc. I have
done some short manual logging of the mass position of the
VBB seismometer when the atmospherics were quiet (high 
pressure), and it seems to be earth tidal. But until I get 
the pressure and temperature under control, logging such 
would be useless. Then I will connect up the miniature strip 
chart recorders we use for tiltmeter data.

Speaking of which, you might be interested that I have been
operating a very old Geodynamics Recording Gravimeter here since I
arrived in '69. It is a quartz suspension, with capacitive
displacement output, using double active thermal jackets and
passive pressure control (a sealed acryllic case). Not the 
current superconducting art, but a good teaching/interest aid.
I have closely followed these instruments; we have a NIST? site
in our basement that they periodically occupy with the lasar+
corner-cube + "superspring" instrument.

Regards,
Sean-Thomas


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From: Fred Gibson 
Subject: Re: MEK to remove glue
Date: Wed, 29 Jul 1998 01:11:54 -0400

Hello all,

Being a former adhesive chemist, thought a few tricks might be helpful.  It
would be less effective, but isopropyl alcohol, IPA, will slowly soften
many adhesives.  IPA will be less likely to destroy a plastic part, but can
fog some clear panels.  Best to try a small spot to see.  From a safety
point of view, gloves and ventilation is the key with anything other than
water.  I havn't looked at the recent bottles of fingernail polish remover
(they once used Acetone) but it may work as well since nail polish is a
coating.


Fred

09:13 PM 7/27/98 -0700, you wrote:
>
>>Bob Lamb recently suggested using MEK solvent to assist in
>>dissolving glue holding magnets and metal washers from speakers;
>>and of course for other parts desired.  It will remove paint and
>>ruin plastic of course.
>
>Acetone works well also and has same problems.....
>   I worked with 50-50 acetone water in a fine spray mist for 2 years
>inside of a very closed environment. The results was major brain and liver
>damage and to this day I receive disability because of it...Watch out for
>solvents!
>
>
>_____________________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email listserver@............. with the body of the 
>message: leave PSN-L
>


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From: Steve Hammond 
Subject: Re: Include PSN in seismic network survey?
Date: Tue, 28 Jul 1998 21:13:01 -0700

Here is the station list for the Assesmrnt and IASPEI Handbook that
Steve Malone, the CNSS Chair is requesting. Please review your station
information as "I" (as in there is danger here...) defined your station
SEED-LIKE type based on the inputs you gave to Dave some time back. If
you don't agree please cut-out the line and send the old line and new
inputs to me in a note at:
 
Shammon1@.............  

Alos, if you don't want to be included you must tell me now. What you
see is what you get--  

You have until Wed. JULY 29 to make your comments because the deadline
for submission is July 31. 
 
_____________________________  Legend
_________________________________________________
Field 1
	Station Operator
Field 2
	Latitude	Longitude
Field 3
	XXX  see legend  (1st,2nd,3rd charachter

1st charachter

	J = Short period <10 seconds
	O = Long-period >10 seconds
	E = Accelerometer

2nd charachter
	S = Short period corner <10 seconds
	B = Broad Band 10 to 89 seconds corner > 10 seconds
	H = smoke / chart recorder >80 seconds

3rd charachter

	Number of orientations (ie 1-single channel, 2..,  3... )

Field 4 Network Name (PSN NetWork)

_____________________________ LIST starts
_____________________________________________

"Name:            Grayling School, Alaska "							GRY	62.8	-160.1	JS1
PSN
"Name:            HSC;  Fairbanks, Alaska"							HSC	62.8	-160.1	JS1	PSN
"Name:            McGrath School, Alaska"							MCG	62.9	-155.6	JS1	PSN
"Name:            Pearl Creek School, Alaska"							PCK	64.9	-147.8	JS1
PSN
"Name:            SRA,  Fairbanks, Alaska"							SRA	62.8	-160.1	JS1	PSN
"Name:           Al Allworth    
W7PXX                                                   (51)							AA1
42.51	-124.33	JS1	PSN
"Name:           Albert Judge 
(Alby)                                                    (37)							AJ1
-32	115	OB1	PSN
"Name:           Almaden Country School, Middle School Science Class  
(48)"							ACS	37.12	-121.5	OB1	PSN
NAME:           Arie 
Verveer                                                          
(59)							AV1	-32.0083	116.1346	OB2	PSN
NAME:           Barry
Lotz                                                             
(15)							BL1	39.23	-121.07	OB1	PSN
NAME:           Bill
Scolnik                                                           
(28)							BS1	41.05	-74.25	JS1	PSN
NAME:           Bill
Scolnik                                                            (28)
		BS2	33.5	-74.25	OB2	PSN
NAME:           Bob
Hammond                                                            
(13)							BH1	64.921	-147.937	JH1	PSN
NAME:           Bob
Hammond                                                            
(13)							BH2	64.921	-147.937	OH1	PSN
NAME:           Bob Lewis   
WB5FDF                                                   (39)							FD1
33.1	-96.43	OB1	PSN
NAME:           Bob Lewis   
WB5FDF                                                   (39)							FD2
33.1	-96.43	JS1	PSN
NAME:           Bob
Teller                                                             
(9)							BT1	46.19	-111.3	OB3	PSN
NAME:           Brian
Zimmerman                                                        
(16)							BZ1	41.875	-80.125	JS1	PSN
NAME:           Brian
Zimmerman                                                        
(16)							BZ2	41.875	-80.125	OB2	PSN
NAME:           Bruce Kinney
			BK1	37.24	-121.839	OB1	PSN
NAME:           Charlie
Rond                                                           
(35)							CR1	35.041	-89.84	OB1	PSN
NAME:           Charlie
Thompson                                                       
(10)							BUE	30.112	-97.891	OB2	PSN
Name:           Clark
Wockner                                                          
(43)							CW1	40.78	-87.75	OB1	PSN
NAME:           Claudio
Conti                                                          
(58)							CC1	37.035	15.135	OB1	PSN
NAME:           Claudio
Conti                                                          
(58)							CC2	37.035	15.135	SJ3	PSN
NAME:           Darrell
Collins                                                        
(27)							DC1	33.5	-111.9	JS1	PSN
NAME:           Darrell
Collins                                                        
(27)							DC2	33.5	-111.9	OB2	PSN
NAME:           Dave Nelson    
ZL4TBN                                                  (4)							DN1
-45.8	170.3	JS1	PSN
NAME:           Dave Nelson    
ZL4TBN                                                  (4)							DN2
-45.8	170.3	JS1	PSN
NAME:           Dave Nelson    
ZL4TBN                                                  (4)							DN3
-45.8	170.3	JS1	PSN
NAME:           Dave Nelson    
ZL4TBN                                                  (4)							DN4
-45.8	170.3	OB1	PSN
NAME:           David
Wolny                                                            
(34)							DW1	39.091	-108.487	OB1	PSN
NAME:           Dennis
Leatart                                                         
(8)							DL1	34.1	-118.88	JS1	PSN
NAME:           Dick
Webb                                                              
(30)							RW1	35.54	-78.39	OB1	PSN
Name:           Donald Sieber
(retired)                                                 (47)							DS1
43.61	-116.21	JS1	PSN
NAME:           Douglas
McConnell                                                      
(49)							DM1	-30.317	149.988	OH1	PSN
NAME:           Francesco
Nucera                                                        (53)						
FN1	43.48	13.48	ES1	PSN
NAME:           Francesco
Nucera                                                        (53)						
FN2	39.96	-82.98	OB1	PSN
NAME:           Frank Cooper   
W5VID                                                   (20)							FC1
29.52	-95.17	OB1	PSN
NAME:           Fred
Bruenjes                                                          
(2)							FB1	32.822	-117.084	OB1	PSN
NAME:           Fred
Bruenjes                                                          
(2)							FB2	32.822	-117.084	OB1	PSN
NAME:           George
Bush                                                            
(14)							TSR	38.74	-123.5	ES3	PSN
NAME:           Giovanni
Rotta                                                         
(45)							GR1	46.22	13.18	OB1	PSN
NAME:           Gregory A.
Lyzenga                                                      (7)						
GL1	34.20N	-118.13	OB1	PSN
NAME:           Jack
Sandgathe                                                         
(23)							JS1	49.35	-119.62	OB1	PSN
NAME:           Jan Froom	
			GC1	37.5	-121.1	OB2	PSN
NAME:           Jan Froom	
			GC2	37.5	-121.1	JS1	PSN
NAME:           Jean-Jacques
Hunsinger                                                (41)							JCH
47.5	7	OB1	PSN
"NAME:           Jeff Batten  ( Caltech Seismo Lab. Pasadena, Ca.)    
(25)"							JB1	34.13	-118.12	JS2	PSN
"NAME:           Jeff Batten  ( Caltech Seismo Lab. Pasadena, Ca.)    
(25)"							JB2	34.13	-118.12	OB1	PSN
"NAME:           Jeff Batten  ( Caltech Seismo Lab. Pasadena, Ca.)    
(25)"							JB3	34.13	-118.12	JH1	PSN
NAME:           Jim
Lovell                                                             
(22)							JL1	-43.52	172.61	OS1	PSN
NAME:           Karl
Cunningham                                                        
(40)							KC1	32.7705	-116.978	JS1	PSN
NAME:           Karl
Cunningham                                                        
(40)							KC2	32.7705	-116.978	ES1	PSN
NAME:           Kees
Verbeek                                                           
(12)							KV1	51.26	5.3	JH1	PSN
NAME:           Ken
Navarre                                                            
(21)							KN1	37.39	-121.99	OB1	PSN
NAME:           Larry
Cochrane                                                         
(1)							LC1	37.496	-122.241	OB1	PSN
NAME:           Larry
Cochrane                                                         
(1)							LC2	37.496	-122.241	JS3	PSN
NAME:           Larry
Cochrane                                                         
(1)							LC3	37.496	-122.241	OB1	PSN
NAME:           Liberio
Rossi                                                          
(56)							LR1	43.54	10.34	JS3	PSN
NAME:           Lucas
Haag                                                             
(11)							LH1	40.13N	-100.29	JS1	PSN
NAME:           Malcolm
Sinclair                                                       
(32)							DHQ	-45.6	170.4	JH1	PSN
NAME:           Malcolm
Sinclair                                                       
(32)							MS1	-43.55	172.68	JH1	PSN
NAME:           Mark
Halliday                                                          
(5)							MH1	37.085	-122.106	JS1	PSN
NAME:           Mark
Halliday                                                          
(5)							MH2	37.085	-122.106	OB1	PSN
Name:           Martin S.
Brewer                                                        (44)						
MB1	32.278	-64.793	OB2	PSN
NAME:           Meredith
Lamb                                                          
(52)							ML1	39.703	-105.006	OB3	PSN
NAME:           Paolo
Frediani                                                         
(57)							PF1	44.13	10.06	SJ2	PSN
NAME:           Paolo
Frediani                                                         
(57)							PF2	44.13	10.06	OB1	PSN
"NAME:           Peter Styles, Sam
Toon                                                (36)"							ST1	53.4
-2.96	JS1	PSN
NAME:           Phil
Giannini                                                          
(17)							SFX	37.72	-122.416	OB2	PSN
NAME:           Phil
Giannini                                                          
(17)							SFZ	37.72	-122.416	JS1	PSN
NAME:           Phil
Giannini                                                          
(17)							SMX	37.75	-122.2	JN3	PSN
NAME:           Phil
Giannini                                                          
(17)							SMZ	37.75	-122.2	JN3	PSN
NAME:           Phil
Giannini                                                          
(17)							TVN	37.75	-122.2	OB1	PSN
NAME:           Phil
Giannini                                                          
(17)							TVZ	37.75	-122.2	JS1	PSN
NAME:           Richard Chelberg
			RC1	37.24	-121.845	OB1	PSN
NAME:           Robert (Bob) L.
Barns                                                   (3)							RB1
40.6802N	-74.4142	OB1	PSN
NAME:           Robert L.
Laney                                                         (50)						
RL1	38.902	-77.38	OB2	PSN
NAME:           Roberto E.
Pozzo                                                        (38)						
RP1	44.46	8.21	OB1	PSN
NAME:           Roberto E.
Pozzo                                                        (38)						
RP2	44.46	8.21	JS1	PSN
NAME:           Roger
Griggs                                                           
(6)							RG1	37.98	-121.72	OB1	PSN
NAME:           Roger
Sorensen                                                         
(19)							RS1	34.16	-118.36	ES2	PSN
NAME:           Roger
Sorensen                                                         
(19)							RS2	34.16	-118.36	JS3	PSN
Name:           Ron
Westfall                                                           
(42)							RW1	49.325	-122.996	OB2	PSN
NAME:           Southland Boys High
School                                         (60)							SHS	-46.5
168.2	SJ1	PSN
NAME:           Stephen
Mortensen                                                      
(55)							SM1	38.828	-120.978	OB1	PSN
NAME:           Steve
Clark                                                            
(24)							SC1	44.99	-122.96	JS1	PSN
NAME:           Steve
Hammond                                                          
(18)							FSX	37.245	-121.815	OB2	PSN
NAME:           Steve
Hammond                                                          
(18)							FSZ	37.245	-121.815	JS3	PSN
NAME:           Tom
Frey                                                               
(26)							LK1	47.17	-122.49	OB1	PSN
NAME:           Tony
Potenzo                                                           
(46)							TP1	19.723	-155.991	OB1	PSN
NAME:           Tony
Potenzo                                                           
(46)							TP2	19.723	-155.991	JS1	PSN
NAME:           Walt
Catino                                                            
(29)							WC1	45.42	-123.04	SL2	PSN

_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: "Al Allworth" 
Subject: RE: MEK to remove glue
Date: Tue, 28 Jul 1998 23:11:56 -0700

Hi All,

The last speaker I tried to take apart was assembled with epoxy. It was so
strong that the
magnet broke. A thin layer of magnet material stayed on the frame. I don't
know if there is anything that will soften epoxy. I know alcohol or acetone
has no effect.

> -----Original Message-----
> From: Fred Gibson [mailto:fgibson@.......
> Sent: Tuesday, July 28, 1998 10:12 PM
> To: PSN-L Mailing List
> Subject: Re: MEK to remove glue
>
>
> Hello all,
>
> Being a former adhesive chemist, thought a few tricks might be
> helpful.  It
> would be less effective, but isopropyl alcohol, IPA, will slowly soften
> many adhesives.  IPA will be less likely to destroy a plastic
> part, but can
> fog some clear panels.  Best to try a small spot to see.  From a safety
> point of view, gloves and ventilation is the key with anything other than
> water.  I havn't looked at the recent bottles of fingernail polish remover
> (they once used Acetone) but it may work as well since nail polish is a
> coating.
>
>
> Fred
>
> 09:13 PM 7/27/98 -0700, you wrote:
> >
> >>Bob Lamb recently suggested using MEK solvent to assist in
> >>dissolving glue holding magnets and metal washers from speakers;
> >>and of course for other parts desired.  It will remove paint and
> >>ruin plastic of course.
> >
> >Acetone works well also and has same problems.....
> >   I worked with 50-50 acetone water in a fine spray mist for 2 years
> >inside of a very closed environment. The results was major brain
> and liver
> >damage and to this day I receive disability because of it...Watch out for
> >solvents!
> >
> >
> >_____________________________________________________________________
> >
> >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: Hubert Vroomen 
Subject: several points regarding thermal, pressure and bouyancy
Date: Wed, 29 Jul 1998 12:45:36 +0200

Hello Sean-Thomas and others,

Thanks for your answers regarding bouyancy effects and temperature
compensation.

BTW, what do you mean by antiqueing your corvette? At this side of the
ocean, a corvette is considered a classic (as probably a BMW or Porsche at
your side), so you do not have to make it an antique to have a special car
:-).

>Re the seis barometric compensation with sealed pill jars installed
>on the back side of the hinges: again, an experiment with an 
>indefinite result. It seemed to help, but not notably; I suspect 
>that they were actually flexing (plastic caps) with small changes 
>of pressure. And figuring the correct volume*moment wrt. the boom
>and the seis mass was an ambiguous endeavor.  I have thought of 
>trying a copper toilet tank float if a real lightweight could be 
>found. Or even some very low density but impervious solid.

I am thinking about a material that would fullfil these requirements, but
have not found anything. he closest I have come is using a glass jar with a
small glass plate waxed over the opening (should be stiffer than a plastic
cap). But to be honest, I doubt if the flexing of the caps would be so
notable, we are talking small pressure differences here, and the plasic
caps I know are pretty stiff, but one should rather try to calculate this
effect than theorise (mea culpa)! To tune the volume you could use a glass
tube of the correct lenght and seal both end with waxed glass plates. 

Determination of the volume of a irregular object is easy (as long as you
do not mind drying it afterwards). Just take a basket of water filled to
the rim, place it on a scale and write down the weight, place the object to
be measured in the basket (it should sink!) and take care that the spilling
water does not enter the scale. Remove the object and measure the weight
again, the difference with the first number is the mass of the water that
was spilled because of the volume of the object. Divide this mass by the
specific mass of the water at the measuring temperature, and you have the
volume of the object.

Measuring the volume-moment around a certain axis is much more difficult,
you could do volume measurements of parts of the same material, and
multiply these volumes with the lever arms of the center of gravity (which
is also the center of volume of homogeneous materials/objects) around the
axis. Much more work but doable, rather inconvenient if you have already
assembled the seismometer.

>In the mean time, the terraraium awaits being fitted out as a
>pressure containment; not to be evacuated, but just to lengthen
>the pressure time constant to several hours. I am working on a
>way to pass the support of the seis through the glass bottom to
>the pier in such a way that pressure flexing of the bottom does
>not move the seis vertically. The other problem is a tight seal:
>a small pinhole leak will breathe and blow the mass around.

Have you thought about using the terrarium upside-down, putting a generous
bead of silicone on your pier around the seismometer, pressing the cables
in this bead (with more silicone to follow) and pressing the terrarium
upside-down in this bead. If the tiles of your pier are close enough, this
concept might work and could give you a simple solution. This way, the
seismometer could still stand on the original pier with unmodified support.

>The other idea is to shrink the design by at least 1/2 so it will
>fit inside a large old fashioned pressure canner (Sears sells them).
>They are cast aluminum and will hold a vacuum.

I have some ideas in which the base of the seismometer is also the pressure
containment (I am very into exostructures). But it would need a rather
large chunk of stainless steel (expensive) or aluminium (cheaper but not
ideal because of the different thermal expansion compared to the
leaf-spring) and could still be to weak to stand larger pressure changes.
If my time permits (end of october or so) I will try to make a drawing of
it, at this moment it only exists in my head.

>I forgot to mention the plan C for temperature: to put an
>aquarium heater in a large (liter+) jar of water inside the
>seis case. They control within a degree F, and the jar of
>water would average out the cycling of the heater. Maaybe
>the heater can be broken into to refine its sensitivity.

good idea, water is a good thermal buffer. The only disadvantage I see is
the possible corrosion danger and the problem of local condensation, which
would lead to changes of the weight of the mass/beam structure (funny jumps
in the output would be the result). Both problems can be countered by
sealing the heated jar vapourtight.

>Speaking of which, you might be interested that I have been
>operating a very old Geodynamics Recording Gravimeter here since I
>arrived in '69. It is a quartz suspension, with capacitive
>displacement output, using double active thermal jackets and
>passive pressure control (a sealed acryllic case). Not the 
>current superconducting art, but a good teaching/interest aid.

Is this a follow-up of the old Worden gravimeter (it was optical if I
remember well)? I know that in Australia or New Zealand a new quartz
suspension gravimeter has been build by Hugill (beginning of the 80-ties)
that also uses capacitive displacement sensoring. It is marketed by a
Canadian company I believe.

>I have closely followed these instruments; we have a NIST? site
>in our basement that they periodically occupy with the lasar+
>corner-cube + "superspring" instrument.

really? Well, that probably means no hip-hop parties then, isn't it? I have
read some papers by those guys and it is a really marvelous instrument.
With proper electronics, the "superspring" concept could also be a
candidate for a vertical seismometer (like every vertically swinging object
with sufficiently large period).

BTW, Walt Williams asked in a seperate post about calibration of
gravimeters. This NIST instrument is one of the absolute gravimeters
(free-fall instrument) that is used to map gravity calibration ranges
around the world.


regards,

Hubert


PS Sean-Thomas, as you have some years of experience in this field. Do you
have any information about the bodenseewerke GSS20 respectively askania
GSS2/KSS2 ship-born gravity sensor. I am in desperate need for
documentation on this instrument and the original manufacturer
(Bodenseewerke in Meersburg, Germany) could not help me anymore.

_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: Edward Cranswick 
Subject: Re: Include PSN in seismic network survey?
Date: Wed, 29 Jul 1998 11:59:53 -0600

Steve-
    I think your list is great!  You could just go ahead and send a copy to Steve Malone directly when you think it is ready (t
onight
being the deadline for changes as you suggested), and CC a copy to the PSN-L and me.  Include the note he sent to me and that I

forwarded to you and PSN-L so he knows where it is coming from.  Thank you very much for putting this together.
    Regards to the family.
-Edward

Steve Hammond wrote:

> Hi Steve,
> I have the station list together for the Public Seismic Network and it
> is out for review on the PSN mail list. The group has until Wed. to
> reply. At that point I will cut off the Station operator field and send
> you the station list as requested. Items 1 - 13 for the handbook will
> follow ASAP. Here is a Sample. We currently have 94 stations in the
> list.
> Regards, Steve Hammond PSN San Jose
>
> ----------- legend -------------
> Field 1
>         Station Operator
> Field 2
>         Latitude        Longitude
> Field 3
>         XXX  see legend  (1st,2nd,3rd charachter
>
> 1st charachter
>
>         J = Short period <10 seconds
>         O = Long-period >10 seconds
>         E = Accelerometer
>
> 2nd charachter
>         S = Short period corner <10 seconds
>         B = Broad Band 10 to 89 seconds
>         H = smoke / chart recorder >80 seconds
>
> 3rd charachter
>
>         Number of orientations (ie 1-single channel)
>
> Field 4 Network Name
>
> ------------------ Sample data ----------------------------------
>
> "Name:            Grayling School, Alaska "                                                     GRY     62.8    -160.1  JS1
> PSN
> "Name:            HSC;  Fairbanks, Alaska"                                                      HSC     62.8    -160.1  JS1  
   PSN
> "Name:            McGrath School, Alaska"                                                       MCG     62.9    -155.6  JS1  
   PSN
> "Name:            Pearl Creek School, Alaska"                                                   PCK     64.9    -147.8  JS1
> PSN
> "Name:            SRA,  Fairbanks, Alaska"                                                      SRA     62.8    -160.1  JS1  
   PSN
> "Name:           Al Allworth
> W7PXX                                                   (51)                                                    AA1
> 42.51   -124.33 JS1     PSN
> "Name:           Albert Judge
> (Alby)                                                    (37)                                                  AJ1
> -32     115     OB1     PSN
> "Name:           Almaden Country School, Middle School Science Class
> (48)"
> ----------------------------  snip snip  -------------------------------
> > *********************************************************************
> > [Steve Malone wrote:]
> >
> >         Also, on a different subject, since I know you are interested and
> > involved in the Peoples Seismograph Network I have a question.  I have
> > been tasked with doing an inventory of seismic networks in the US and am
> > getting a response from most of the regional networks (ie members of the
> > CNSS).  The `PSN' has never been an actual part of the CNSS since it is a
> > pretty ad hoc group with no central authority (as it should).  However,
> > for this inventory (and maybe just to increase its visability it might be



--
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: "Giovanni Rotta" 
Subject: R: Include PSN in seismic network survey?
Date: Wed, 29 Jul 1998 19:47:10 +0200

Hi Steve !
Please, tell me how many time we have to send you the requested data.
Have my best regards,
Giovanni

Giovanni Rotta
rottag@..........
Via F. Pizzigoni, 10
33010 Resia (Udine) Italy
Lat. 46.373N   Long. 13.305E
QTH Locator JN66PI

----------
> Da: Steve Hammond 
> A: PSN-L Mailing List 
> Cc: steve@......................
> Oggetto: Re: Include PSN in seismic network survey?
> Data: mercoledì 29 luglio 1998 6.13
> 
> Here is the station list for the Assesmrnt and IASPEI Handbook that
> Steve Malone, the CNSS Chair is requesting. Please review your station
> information as "I" (as in there is danger here...) defined your station
> SEED-LIKE type based on the inputs you gave to Dave some time back. If
> you don't agree please cut-out the line and send the old line and new
> inputs to me in a note at:
>  
> Shammon1@.............  
> 
> Alos, if you don't want to be included you must tell me now. What you
> see is what you get--  
> 
> You have until Wed. JULY 29 to make your comments because the deadline
> for submission is July 31. 
>  
> _____________________________  Legend
> _________________________________________________
> Field 1
> 	Station Operator
> Field 2
> 	Latitude	Longitude
> Field 3
> 	XXX  see legend  (1st,2nd,3rd charachter
> 
> 1st charachter
> 
> 	J = Short period <10 seconds
> 	O = Long-period >10 seconds
> 	E = Accelerometer
> 
> 2nd charachter
> 	S = Short period corner <10 seconds
> 	B = Broad Band 10 to 89 seconds corner > 10 seconds
> 	H = smoke / chart recorder >80 seconds
> 
> 3rd charachter
> 
> 	Number of orientations (ie 1-single channel, 2..,  3... )
> 
> Field 4 Network Name (PSN NetWork)
> 
> _____________________________ LIST starts
> _____________________________________________
> 
> "Name:            Grayling School, Alaska "							GRY	62.8	-160.1	JS1
> PSN
> "Name:            HSC;  Fairbanks, Alaska"							HSC	62.8	-160.1	JS1	PSN
> "Name:            McGrath School, Alaska"							MCG	62.9	-155.6	JS1	PSN
> "Name:            Pearl Creek School, Alaska"							PCK	64.9	-147.8	JS1
> PSN
> "Name:            SRA,  Fairbanks, Alaska"							SRA	62.8	-160.1	JS1	PSN
> "Name:           Al Allworth    
> W7PXX                                                   (51)							AA1
> 42.51	-124.33	JS1	PSN
> "Name:           Albert Judge 
> (Alby)                                                    (37)							AJ1
> -32	115	OB1	PSN
> "Name:           Almaden Country School, Middle School Science Class  
> (48)"							ACS	37.12	-121.5	OB1	PSN
> NAME:           Arie 
> Verveer                                                          
> (59)							AV1	-32.0083	116.1346	OB2	PSN
> NAME:           Barry
> Lotz                                                             
> (15)							BL1	39.23	-121.07	OB1	PSN
> NAME:           Bill
> Scolnik                                                           
> (28)							BS1	41.05	-74.25	JS1	PSN
> NAME:           Bill
> Scolnik                                                            (28)
> 		BS2	33.5	-74.25	OB2	PSN
> NAME:           Bob
> Hammond                                                            
> (13)							BH1	64.921	-147.937	JH1	PSN
> NAME:           Bob
> Hammond                                                            
> (13)							BH2	64.921	-147.937	OH1	PSN
> NAME:           Bob Lewis   
> WB5FDF                                                   (39)							FD1
> 33.1	-96.43	OB1	PSN
> NAME:           Bob Lewis   
> WB5FDF                                                   (39)							FD2
> 33.1	-96.43	JS1	PSN
> NAME:           Bob
> Teller                                                             
> (9)							BT1	46.19	-111.3	OB3	PSN
> NAME:           Brian
> Zimmerman                                                        
> (16)							BZ1	41.875	-80.125	JS1	PSN
> NAME:           Brian
> Zimmerman                                                        
> (16)							BZ2	41.875	-80.125	OB2	PSN
> NAME:           Bruce Kinney
> 			BK1	37.24	-121.839	OB1	PSN
> NAME:           Charlie
> Rond                                                           
> (35)							CR1	35.041	-89.84	OB1	PSN
> NAME:           Charlie
> Thompson                                                       
> (10)							BUE	30.112	-97.891	OB2	PSN
> Name:           Clark
> Wockner                                                          
> (43)							CW1	40.78	-87.75	OB1	PSN
> NAME:           Claudio
> Conti                                                          
> (58)							CC1	37.035	15.135	OB1	PSN
> NAME:           Claudio
> Conti                                                          
> (58)							CC2	37.035	15.135	SJ3	PSN
> NAME:           Darrell
> Collins                                                        
> (27)							DC1	33.5	-111.9	JS1	PSN
> NAME:           Darrell
> Collins                                                        
> (27)							DC2	33.5	-111.9	OB2	PSN
> NAME:           Dave Nelson    
> ZL4TBN                                                  (4)							DN1
> -45.8	170.3	JS1	PSN
> NAME:           Dave Nelson    
> ZL4TBN                                                  (4)							DN2
> -45.8	170.3	JS1	PSN
> NAME:           Dave Nelson    
> ZL4TBN                                                  (4)							DN3
> -45.8	170.3	JS1	PSN
> NAME:           Dave Nelson    
> ZL4TBN                                                  (4)							DN4
> -45.8	170.3	OB1	PSN
> NAME:           David
> Wolny                                                            
> (34)							DW1	39.091	-108.487	OB1	PSN
> NAME:           Dennis
> Leatart                                                         
> (8)							DL1	34.1	-118.88	JS1	PSN
> NAME:           Dick
> Webb                                                              
> (30)							RW1	35.54	-78.39	OB1	PSN
> Name:           Donald Sieber
> (retired)                                                 (47)							DS1
> 43.61	-116.21	JS1	PSN
> NAME:           Douglas
> McConnell                                                      
> (49)							DM1	-30.317	149.988	OH1	PSN
> NAME:           Francesco
> Nucera                                                        (53)						
> FN1	43.48	13.48	ES1	PSN
> NAME:           Francesco
> Nucera                                                        (53)						
> FN2	39.96	-82.98	OB1	PSN
> NAME:           Frank Cooper   
> W5VID                                                   (20)							FC1
> 29.52	-95.17	OB1	PSN
> NAME:           Fred
> Bruenjes                                                          
> (2)							FB1	32.822	-117.084	OB1	PSN
> NAME:           Fred
> Bruenjes                                                          
> (2)							FB2	32.822	-117.084	OB1	PSN
> NAME:           George
> Bush                                                            
> (14)							TSR	38.74	-123.5	ES3	PSN
> NAME:           Giovanni
> Rotta                                                         
> (45)							GR1	46.22	13.18	OB1	PSN
> NAME:           Gregory A.
> Lyzenga                                                      (7)						
> GL1	34.20N	-118.13	OB1	PSN
> NAME:           Jack
> Sandgathe                                                         
> (23)							JS1	49.35	-119.62	OB1	PSN
> NAME:           Jan Froom	
> 			GC1	37.5	-121.1	OB2	PSN
> NAME:           Jan Froom	
> 			GC2	37.5	-121.1	JS1	PSN
> NAME:           Jean-Jacques
> Hunsinger                                                (41)							JCH
> 47.5	7	OB1	PSN
> "NAME:           Jeff Batten  ( Caltech Seismo Lab. Pasadena, Ca.)    
> (25)"							JB1	34.13	-118.12	JS2	PSN
> "NAME:           Jeff Batten  ( Caltech Seismo Lab. Pasadena, Ca.)    
> (25)"							JB2	34.13	-118.12	OB1	PSN
> "NAME:           Jeff Batten  ( Caltech Seismo Lab. Pasadena, Ca.)    
> (25)"							JB3	34.13	-118.12	JH1	PSN
> NAME:           Jim
> Lovell                                                             
> (22)							JL1	-43.52	172.61	OS1	PSN
> NAME:           Karl
> Cunningham                                                        
> (40)							KC1	32.7705	-116.978	JS1	PSN
> NAME:           Karl
> Cunningham                                                        
> (40)							KC2	32.7705	-116.978	ES1	PSN
> NAME:           Kees
> Verbeek                                                           
> (12)							KV1	51.26	5.3	JH1	PSN
> NAME:           Ken
> Navarre                                                            
> (21)							KN1	37.39	-121.99	OB1	PSN
> NAME:           Larry
> Cochrane                                                         
> (1)							LC1	37.496	-122.241	OB1	PSN
> NAME:           Larry
> Cochrane                                                         
> (1)							LC2	37.496	-122.241	JS3	PSN
> NAME:           Larry
> Cochrane                                                         
> (1)							LC3	37.496	-122.241	OB1	PSN
> NAME:           Liberio
> Rossi                                                          
> (56)							LR1	43.54	10.34	JS3	PSN
> NAME:           Lucas
> Haag                                                             
> (11)							LH1	40.13N	-100.29	JS1	PSN
> NAME:           Malcolm
> Sinclair                                                       
> (32)							DHQ	-45.6	170.4	JH1	PSN
> NAME:           Malcolm
> Sinclair                                                       
> (32)							MS1	-43.55	172.68	JH1	PSN
> NAME:           Mark
> Halliday                                                          
> (5)							MH1	37.085	-122.106	JS1	PSN
> NAME:           Mark
> Halliday                                                          
> (5)							MH2	37.085	-122.106	OB1	PSN
> Name:           Martin S.
> Brewer                                                        (44)						
> MB1	32.278	-64.793	OB2	PSN
> NAME:           Meredith
> Lamb                                                          
> (52)							ML1	39.703	-105.006	OB3	PSN
> NAME:           Paolo
> Frediani                                                         
> (57)							PF1	44.13	10.06	SJ2	PSN
> NAME:           Paolo
> Frediani                                                         
> (57)							PF2	44.13	10.06	OB1	PSN
> "NAME:           Peter Styles, Sam
> Toon                                                (36)"							ST1	53.4
> -2.96	JS1	PSN
> NAME:           Phil
> Giannini                                                          
> (17)							SFX	37.72	-122.416	OB2	PSN
> NAME:           Phil
> Giannini                                                          
> (17)							SFZ	37.72	-122.416	JS1	PSN
> NAME:           Phil
> Giannini                                                          
> (17)							SMX	37.75	-122.2	JN3	PSN
> NAME:           Phil
> Giannini                                                          
> (17)							SMZ	37.75	-122.2	JN3	PSN
> NAME:           Phil
> Giannini                                                          
> (17)							TVN	37.75	-122.2	OB1	PSN
> NAME:           Phil
> Giannini                                                          
> (17)							TVZ	37.75	-122.2	JS1	PSN
> NAME:           Richard Chelberg
> 			RC1	37.24	-121.845	OB1	PSN
> NAME:           Robert (Bob) L.
> Barns                                                   (3)							RB1
> 40.6802N	-74.4142	OB1	PSN
> NAME:           Robert L.
> Laney                                                         (50)						
> RL1	38.902	-77.38	OB2	PSN
> NAME:           Roberto E.
> Pozzo                                                        (38)						
> RP1	44.46	8.21	OB1	PSN
> NAME:           Roberto E.
> Pozzo                                                        (38)						
> RP2	44.46	8.21	JS1	PSN
> NAME:           Roger
> Griggs                                                           
> (6)							RG1	37.98	-121.72	OB1	PSN
> NAME:           Roger
> Sorensen                                                         
> (19)							RS1	34.16	-118.36	ES2	PSN
> NAME:           Roger
> Sorensen                                                         
> (19)							RS2	34.16	-118.36	JS3	PSN
> Name:           Ron
> Westfall                                                           
> (42)							RW1	49.325	-122.996	OB2	PSN
> NAME:           Southland Boys High
> School                                         (60)							SHS	-46.5
> 168.2	SJ1	PSN
> NAME:           Stephen
> Mortensen                                                      
> (55)							SM1	38.828	-120.978	OB1	PSN
> NAME:           Steve
> Clark                                                            
> (24)							SC1	44.99	-122.96	JS1	PSN
> NAME:           Steve
> Hammond                                                          
> (18)							FSX	37.245	-121.815	OB2	PSN
> NAME:           Steve
> Hammond                                                          
> (18)							FSZ	37.245	-121.815	JS3	PSN
> NAME:           Tom
> Frey                                                               
> (26)							LK1	47.17	-122.49	OB1	PSN
> NAME:           Tony
> Potenzo                                                           
> (46)							TP1	19.723	-155.991	OB1	PSN
> NAME:           Tony
> Potenzo                                                           
> (46)							TP2	19.723	-155.991	JS1	PSN
> NAME:           Walt
> Catino                                                            
> (29)							WC1	45.42	-123.04	SL2	PSN
> 
> _____________________________________________________________________
> 
> Public Seismic Network Mailing List (PSN-L)
> 
> To leave this list email listserver@............. with the body of the 
> message: leave PSN-L

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From: Doug Crice 
Subject: Corvettes
Date: Wed, 29 Jul 1998 11:56:37 -0700

Sean:

I find it difficlut to believe that someone who builds a world class
seismograph from scratch can't machine a set of brake callipers from
scrap laying around the lab  :)
-- 
Doug Crice          web site http://www.georadar.com
GeoRadar Inc.             e-mail dcrice@............
19623 Via Escuela Drive           phone 408-867-3792
Saratoga, CA 95070 USA              fax 408-867-4900



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From: Hubert Vroomen 
Subject: Re: More surplus geophones & etc.
Date: Wed, 29 Jul 1998 21:29:44 +0200

Hello Meredith,

I did not find information on the allcorp geophones on their web-site. As I
do not want to download the whole 3.2 MB catalog, can you give me a small
clue where to find this info (I looked at their chapter "transducers" and
some other chapters but didn't find anything)

Thanks,

Hubert

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From: S-T Morrissey 
Subject: Askania gravimeter
Date: Wed, 29 Jul 1998 15:19:10 -0500 (CDT)

Hubert,
We do have an unidentified object that is reported to be a gravimeter
in a large (.5m x .5m x1m) gimballed case for ship-born operation.
It is in my underground test (munitions) vault; I have never looked into just
exactly what instrument is in there. rumor has it that it may be
an old optical Worden instrument. I have to go to the remote site next
week (lightning zapped the telemetry from it), so I can look into it.
Unfortunately, I have no literature on it. The only Ascania info I have
is on their borehole tiltmeter, with the hip-hop ball calibration.

Thanks for your other comments. For the barometric compensation volumes,
we need to keep the mass as minimal as possibe, since the added mass
changes the center of gravity of the boom.  Any glass container would
have to be vary light.

I have considered using the terrarium inverted as a cover over the sensor 
and sealed to a baseplate on the pier surface. The STS-1 is set up this 
way; the 2cm thick pyrex baseplates of the instruments are vacuum-grouted 
to the pier surface, and the large glass bell jar sits on large circular
flat gaskets that are sealed by the atmospheric pressure when the bell is
evacuated. The cable/connector is through a hole bored in the edge of
the glass plate. For the homemade seis, I do not know if I can make a
useful seal to the large tiles on top of the pier, so I am considering 
epoxing a large acrillic plate to the pier surface to accomplish a 
similar result.
However, I would not want a permanent seal for the cover, since the it
needs to be removed to work on the seis. So the hunt is on for a suitable flat
gasket or weatherstrip that can be made pressure tight. McMaster has
a large selection of such, if the local hardware stores don't.

I may try the aquarium heater in a large container of fine sand rather
than water to avoid the humidity problem.

regards,
Sean-Thomas

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From: Karl Cunningham 
Subject: Re: period/mass etc of STM/ Nitinol actuators
Date: Wed, 29 Jul 1998 13:45:45 -0700

Another thought about centering..

It seems that using the motor approach of Sean-Thomas has some advantages
-- it contributes very little noise and heat when not in use, and it
doesn't drift much.  For those not happy with mounting the motor on the
boom, how about a very small-geometry flexure (spring) which would extend
down from the area of the other flexures to the baseplate and be deflected
by a nut on a motor-driven lead screw.  This small flexure would bend and
provide a restoring force that is adjustable using the motor.  I think the
reduction in natural period due to the addition of this flexure could be
compensated for by an adjustment of the leaf spring position.  As in
Sean-Thomas' approach, a periodic evaluation of the centering of the system
could be used.

Just another $.02

                                                           \
          |------------------------------------------------/
          |         Boom                                   \
   |-----|+-+----------------------------------------------\ 
   |     |  |                                              /
   |     |  |
   |     |  | New Flexure
   |     |  | 
   |     |  |
   |     |  |  Lead
   |     |  |  Screw  |-------|
   |     | x=xxxxxxxx-| Motor |-
   |     |  |         |-------|                         
   |     |             /\   /\                   BASE
----------------------------------------------------------------------------
-----


Karl Cunningham
La Mesa, CA.
PSN station #40
karlc@.......

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From: Greg 
Subject: Re: More surplus geophones & etc.
Date: Wed, 29 Jul 1998 14:27:58 -0700

Hubert Vroomen wrote:

> clue where to find this info (I looked at their chapter "transducers" and
> some other chapters but didn't find anything)

I looked through a large portion of the "chapters" and didn't find it.
It would have probably been quicker to download the whole thing for me
;) I'm all set for geophones, but I little curious.

,Greg

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From: Hubert Vroomen 
Subject: Re: period/mass etc of STM/ Nitinol actuators
Date: Wed, 29 Jul 1998 23:34:18 +0200

Karl,

I had been thinking about an idea like yours, but thought it might add to
much stiffness to the whole system (shortening the period). Perhaps I
overestimate this effect. I forgot to calculate the exact numbers, but I
think that the range of torque that is needed for thermal adjustment is
quite large (Sean-Thomas speaks about a 10 gram mass over a 10 inch
travel). This would mean that in your concept you either have a flexure
that is stiff (and you don't want that, see above) with small travel or a
flexible flexure with a large travel (which gives problems with kinematics
and non-linearities). 

I would like to repeat my previous idea, borrowing your picture, so it
might be a little clearer:

         |-------------------------------------------------MMMMMM
         |         Beam                                   MMMMMM Mass
   |-----+-----------------------+-------------------------MMMMMM
   |     | pivot        upper    |  ****
   |  S  | flexures     mounting | *    *
   |  u  |                       |*      *
   |  p  |                                *   Zero-length
   |  p  |                                 *  leaf-spring
   |  o  |                                 *
   |  r  |                                 *
   |  t  |   possible motion   <--->      *
   |     |          of           |*      *             
   |     |              lower    | *    *
   |     |              mounting |  ****      Base
---+-----+-----------------------+------------------------------------------

By variing the possition of the lower mounting the moment/torque of the
springforce around the axis of the flexures can be changed, and therewith
the restoring force for the vertical motion of the mass.

Perhaps it is a little bit clearer now, and thanks again for the wonderfull
ASCII art!

regards,

Hubert

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From: Hubert Vroomen 
Subject: Re: Askania gravimeter
Date: Thu, 30 Jul 1998 00:03:45 +0200

Hello Sean-Thomas

>We do have an unidentified object that is reported to be a gravimeter
>in a large (.5m x .5m x1m) gimballed case for ship-born operation.

If it is a round container, with about the dimensions you said, and the
axis of the cylinder in the horizontal plane, it could very well be an
Askania/Bodenseewerke. In my memory all Worden instruments have been
vertical cylinders, with three feet under it for support. And I do not know
of a ship-borne Worden.

At one end of the container you will find the electrical connections and a
measuring microscope. If it is one of the newer instruments (but if it is
on a gimballed platform it probably is not, newer systems are
gyro-stabilised) you will find a gear coming out of the container, with
perhaps an electric motor attached to it (this motor is missing at my
instrument). This motor was used for automatic zeroing (using the signal of
a differential photo-cell) during automatic recording on-sea.

>It is in my underground test (munitions) vault; I have never looked into just
>exactly what instrument is in there. rumor has it that it may be
>an old optical Worden instrument. I have to go to the remote site next
>week (lightning zapped the telemetry from it), so I can look into it.
>Unfortunately, I have no literature on it. The only Ascania info I have
>is on their borehole tiltmeter, with the hip-hop ball calibration.

I am not sure whether this system was also used for the calibration of this
gravimeter. I think it was, I once spoke with the inventor of this gadget,
and he still was very proud about it (no idea why, I still think it is a
funny way of calibrating, but whatever). I am reluctant to open the case of
my gravimeter, as it is a very delicate instrument and I am afraid of
destroying anything without having the proper documentation. BTW the
Askania/Bodenseewerke instruments live under many different names
(KSS5/GSS2/GSS20 and some more that I forgot, mine is a GSS2 which was
(partly) modified to GSS20 standard).

>Thanks for your other comments. For the barometric compensation volumes,
>we need to keep the mass as minimal as possibe, since the added mass
>changes the center of gravity of the boom.  Any glass container would
>have to be vary light.

I know, but glass can be pretty light. And you can use a glass ball (hey,
what about a christmas tree ball! Some of them are airtight and even
evacuated!).

>I have considered using the terrarium inverted as a cover over the sensor 
>and sealed to a baseplate on the pier surface. The STS-1 is set up this 
>way; the 2cm thick pyrex baseplates of the instruments are vacuum-grouted 
>to the pier surface, and the large glass bell jar sits on large circular
>flat gaskets that are sealed by the atmospheric pressure when the bell is
>evacuated. The cable/connector is through a hole bored in the edge of
>the glass plate. For the homemade seis, I do not know if I can make a
>useful seal to the large tiles on top of the pier, so I am considering 
>epoxing a large acrillic plate to the pier surface to accomplish a 
>similar result.
>However, I would not want a permanent seal for the cover, since the it
>needs to be removed to work on the seis. So the hunt is on for a suitable
flat
>gasket or weatherstrip that can be made pressure tight. McMaster has
>a large selection of such, if the local hardware stores don't.

I understand. I once had to build a small vacuum chamber at work, and I
used a steel baseplate with the electrical cables epoxied in it (we removed
the insulation at the pass-through to create a better airlock and forced
epoxy into the free ends of the cables to close them even more. You can
drink like a straw through about 3 meters of RG58 coax cable, no problem!).
Over it we placed a simple bell-jar. For evacuation we used a airco-pump,
it was the cheapest way to achieve reasonable vacuum.

If I were to be to build a pier, I would integrate into the pier a steel or
aluminium rim around the seismometer, of sufficient height to make some
pass-throughs for cables and with an upper surface to mate the terrarium,
either via some silicone or a solid gasket. It is probable much easier to
do this when you are building then afterwards, but you could also try to
mount such a rim to your pier with silicone. It will be not as mechanically
stable, but who cares.

I do not think that you need a baseplate, in my opinion it must be feasible
to seal the terrarium or the rim to the tiles, just use enought silicone
(it is called different in the States, but I forgot the correct name).

>I may try the aquarium heater in a large container of fine sand rather
>than water to avoid the humidity problem.

be careful, the conduction of heat to the sand is less than to the water,
it might destroy your heater.

regards,

Hubert

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From: meredith lamb 
Subject: Re: More surplus geophones & etc.
Date: Wed, 29 Jul 1998 15:04:18 -0600

Hubert,

All Electronics corp., has an email address for catalog request
or....questions:  allcorp@...........   The geophone is on the
last page (pg 96), but it lacks alot of detail.  Probably the best
route is too email and ask.  I emailed a questionaire afew minutes
back...but with all things, we maybe lucky to get an answer.
Lacking that for the present, the only info I have is:.....

Walt Williams information of afew days back:

Walt Williams wrote:

> Hi Meredith & All,
>
> I recently bought several Geosource MD-81, 10 Hz geophones from the
> Van Nuys, California, USA, store. They are packaged exactly the same
> as the Gateway supplier, but are slightly less expensive. Mostly
> same type. They have same diagram and a little perfboard with a LM393
> quad comparator and some resistors. You solder together to make
> simple circuit with red LED.
>
> I put my Tek-465B with x1 probe, 5 mv channel setting directly on
> geophone pins, place on rug (simple low-pass filter :-), lots of 60
> Hz, but works pretty good! I can see cars and trucks passing maybe
> 60 meters from house. Can see cat walking in kitchen, making din din
> run -- no amplifier, surprisingly sensitive! One of the nice folks
> (Roger Sorenson) on PSN sent me TurboCAD layout for geophone amp he
> built, I have hacked that up and made a simple test circuit, works
> well. This is very interesting, lots of good ways to spend boring
> nights!
>
> Cheers,
>
> Walt Williams, 98.07.27
> dfheli@..............
>
>
> Bob Lambs info:
>
> Bobs purchase geophone was a 10hz, 600 ohm, which he
> claims are much more sensitive than the Startronics (Arizona) model
> (14hz) ...roughly by ~8X signal.  Size, 1.6" height X 1.2" diameter.
> Bob is a retired electronics engineer.
>
>

The geophone is not with the transducers.  It looks like a last minute
throw on, on the last page, which was partially used for the mailing
label.  They are used functioning units.  There is more info here, than
on their ad.  Walt says they were "mostly same type", which means more
than one type of course.

If they email me back, I'll put on the PSN email.

Meredith Lamb


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From: Hubert Vroomen 
Subject: STS-1 vacuum-grouting
Date: Thu, 30 Jul 1998 00:35:22 +0200

Sean-Thomas and others,

>I have considered using the terrarium inverted as a cover over the sensor 
>and sealed to a baseplate on the pier surface. The STS-1 is set up this 
>way; the 2cm thick pyrex baseplates of the instruments are vacuum-grouted 
>to the pier surface, and the large glass bell jar sits on large circular

something I have been wanting to ask for a long time :-), what exactly is
vacuum-grouting, and why/how is it done. Is it because of air-bubbles in
the grout under the plate that would cause the plate to warp and tilt at
variing atmospheric pressures? Would it be an advice for future amateur
pier-builders, to top their piers with a plate of glass (as thick as
possible) put into a thick layer of grout/concrete?

I know that here in Germany it is possible to get old pieces of safety
glass from banks (many centimeters thick) for almost nothing, so this could
be a nice pier-top.

I still believe you do not need a real baseplate, just try without it,
simply use the terrarium upside-down (I admit, I just can't wait for
pressure-compensated results from the STM-8)!

regards, and thanks for this continuing interesting discussion,

Hubert

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From: "Charles R. Patton" 
Subject: Re: STS-1 vacuum chamber mouting idea
Date: Wed, 29 Jul 1998 16:34:19 -0700

Previous posts:
>I have considered using the terrarium inverted as a cover over the senso=
r=20
>and sealed to a baseplate on the pier surface.

I couldn=92t resist a comment on a possible method of mounting that would
tend to be pressure insensitive and could be easily used on any floor.=20
How about taking a rigid pipe section =96 maybe 1" to 2" in diameter and
making a pier feedthrough to the actual base plate. Then make your
vacuum plate float on that.  Something like this:

..  +------------------+
..  |                  |  <---Box over Seismometer
..  |                  |       and internal pier
..  |    seismometer   |      (Vacuum chamber
..  |  +------------+  |
..  |  |////////////|  |
..  |  +----+ +-----+  |
..  |       |/|        |
..  |       |/|        |
.. +------+ |/| +-------+
.. |\\\\\\| |/| |\\\\\\\|  Floating plate siliconed
.. +------+ |/| +-------+   on to pier riser
..          |/|
..          |/|
..     +----+ +-----+=20
..     |////////////| Baseplate with adjusment screws
..     +----+-+-----+=20
XXXXXXXXXXXXXXXXXXXXXXXXXXX  Floor or bedrock

Now, even though the vacuum plate flexes, it doesn=92t transmit bending
torque to the seismometer mounting.  The actual construction would be
quite simple.  A standard short nipple section screwed into two pipe
flanges would make the pier feedthrough.  Seal the pipe.  Screw on one
pipe flange, slip the vacuum chamber base plate on, then screw on the
other flange.  Attach two base plates =96 one inside for the seismometer
and one outside for the floor. =20

Charles R. Patton
charles.r.patton@........

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From: Hubert Vroomen 
Subject: Re: STS-1 vacuum chamber mouting idea
Date: Thu, 30 Jul 1998 02:19:00 +0200

Hello Charles and others,

You did draw:
>.  +------------------+
>.  |                  |  <---Box over Seismometer
>.  |                  |       and internal pier
>.  |    seismometer   |      (Vacuum chamber
>.  |  +------------+  |
>.  |  |////////////|  |
>.  |  +----+ +-----+  |
>.  |       |/|        |
>.  |       |/|        |
>. +------+ |/| +-------+
>. |\\\\\\| |/| |\\\\\\\|  Floating plate siliconed
>. +------+ |/| +-------+   on to pier riser
>.          |/|
>.          |/|
>.     +----+ +-----+ 
>.     |////////////| Baseplate with adjusment screws
>.     +----+-+-----+ 
>XXXXXXXXXXXXXXXXXXXXXXXXXXX  Floor or bedrock

I think this could be a good idea. Although a 1" or 2" might be a little
bit to flimsy, it is very well possible to use a larger post or (would be
my favorite) use longer and larger adjustment screws and omit the lower
baseplate, floating the "vacuum plate" to the adjustment screws. I suppose
that this is the kind of construction that Sean-Thomas is thinking about.

Not using any baseplate, either floating or fixed, and sealing the pressure
container to the pier is even simpler off-course, but demands a proper
finish of the pier-top (see my previous mail).

not long 'till we overtake the commercial instruments :-),

regards,

Hubert

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From: Brian Chesire 
Subject: Re: MEK to remove glue
Date: Wed, 29 Jul 1998 17:37:53 -0700

There are two chemicals that will slowly disolve cured epoxy. I've used
them both, maybe I can remember how to spell them.
 1.) Methylene Chloride: Probably on the EPA banned list. I know we
can't even mention it at work anymore.
 2.) Crescylic Acid: Will attack most anything organic. Used as a carbon
dissolver in Bendix "Solv-A-Seal", a 5 gallon bucket with a basket to
hold parts and a layer of oil on top to prevent evaporation, found in
almost all aircraft piston engine shops, also a major ingredient of auto
parts store dip type caburetor cleaner, Found in one gallon cans at my
local parts store. The best teacher is pain, DO NOT, stick your fingers
through the oil layer to find out whats under it. Took about 4 months
for the fingernails to grow back, OUCH.(I was only 12 and not too
bright!!)

Brian WA5PPO
Tucson, AZ

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From: David Josephson 
Subject: Re: MEK to remove glue
Date: Wed, 29 Jul 1998 18:11:47 -0700 (PDT)

> There are two chemicals that will slowly disolve cured epoxy. I've used
> them both, maybe I can remember how to spell them.
>  1.) Methylene Chloride: Probably on the EPA banned list. I know we
> can't even mention it at work anymore.

Available in most hardware stores as regular paint stripper.

>  2.) Crescylic Acid: Will attack most anything organic. Used as a carbon
> dissolver in Bendix "Solv-A-Seal", a 5 gallon bucket with a basket to
> hold parts and a layer of oil on top to prevent evaporation, found in
> almost all aircraft piston engine shops, also a major ingredient of auto

Aka "Turco" and still in aircraft engine shops. May take overnight
to eat epoxy, but it does.

-- 
David Josephson / Josephson Engineering / San Jose CA / david@.............

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From: barry lotz 
Subject: Re: mass buoyancy
Date: Wed, 29 Jul 1998 17:45:49 -0700

Sean Thomas
   I too can't find my calcs, so I ran thru them again. I tend to write
everything on the backs of envelopes. Anyway, for a say 10 degree F temp
change I got an about 2 mg bouyancy. I put a 70mg weight on my sensor
and got a 1.5 vt output . This leads to a 50 mv change. It isn't that
much.
                                          Barry

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From: barry lotz 
Subject: Re: STS-1 vacuum chamber mouting idea
Date: Wed, 29 Jul 1998 17:56:00 -0700

Hi All
   I would be careful about subjecting a flat sided glass terrarium to a
14 psi external pressure(vacuum). Round maybe, where the stresses are
axial. Implosion! If it has been done I would like to know, so I would
be a little less conservative.
                                    Barry

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From: meredith lamb 
Subject: [Fwd: Geophone on sale]
Date: Wed, 29 Jul 1998 20:11:36 -0600


Meredith,

The geophones are made by Geosource Inc., Model # MD-81.  They were
manufactured in 1985 and appear to have been used.  They measure 616 ohms
across the coil.
Guaranteed functional.  That's all we know.

All Electronics Corp



>Sir:
>
>Request more information on your geophone on sale per your
>catalog....pg 96.  Who is the mfgr, model, resistance etc.?  Is
>there more than one type?
>
>Thanks, Meredith Lamb


                ============================================
                        . . . .  . . . . .  . . . . . .
                        . email - allcorp@........... .
                        .   www  and on-line store    .
                        .   http://www.allcorp.com/   .
                        .      phone toll free        .
                        .        888-826-5432         .
                        .     fax 818-781-2653        .
                        . . . . . . . . . . . . . . . .

                ============================================




From: S-T Morrissey 
Subject: vacuum grouting; pier sealing
Date: Thu, 30 Jul 1998 01:17:17 -0500 (CDT)

Hubert and co,

The vacuum grouting of the baseplates of the STS-1 seismometers
is intended to remove air from the grout and from under the glass
baseplate. First a grout slurry is poured in a shallow form and
a 2 ft dia steel dome is placed over it and sealed to the pier with
a very compliant gasket. A dry vane pump then evacuates the dome and
pulls the bubbles out of the grout, which is enhanced with latex
bonding and sealing additives.
Then the glass baseplate is placed in the grout and worked down
about 1 cm, and the steel dome is replaced and again evacuated 
until no further bubbles are evident. This commits the instrument
to a permanent installation.

On the other hand, for the STM designs, I would like to avoid an
installation that cannot be easily modified or relocated, at
least for the present. We need to keep things simple, and while
being acutely aware of potential noise sources, realize that most
practical sites will not warrant ultimate low noise designs. 
So I will be more inclined to work on more "portable" ideas.
The sealed commercial seismometers, especially
the STS-2, incorporate an integral baseplate that is mechanically
isolated from the containment vessel, somewhat along the ideas
just presented here by George P., except on a smaller scale. 

Likewise, I do not think we need to pursue evacuated containment;
we can speculate on the possibilities, but it can also be dangerous.
A containent that has a pressure time constant of several hours will
adequately solve our barometric noise problems.

Regards,
Sean-Thomas

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From: Karl Cunningham 
Subject: Re: period/mass etc of STM/ Nitinol actuators
Date: Thu, 30 Jul 1998 08:16:49 -0700

Hubert --

Thanks for your comments.  I missed the concept of how much correction
Sean-Thomas needed.  Thanks for pointing that out.  It seems that your
method may not affect natural period since it should only change the vector
of the spring's force, and therefore only the mechanical advantage (gain)
of the spring.  I am curious if anyone has equations that describe the
characteristics of a leaf spring when used in this manner.  



Karl Cunningham
La Mesa, CA.
PSN station #40
karlc@.......

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From: Norman Davis WB6SHI 
Subject: Re: aquarium heater?
Date: Wed, 29 Jul 1998 07:17:24

At 08:08 PM 7/28/98 -0500, you wrote:
>Hubert,
>I forgot to mention the plan C for temperature: to put an
>aquarium heater in a large (liter+) jar of water inside the
>seis case. They control within a degree F, and the jar of
>water would average out the cycling of the heater. Maaybe
>the heater can be broken into to refine its sensitivity.

 I was into that stuff a while back and they make a electronic control
heater that is quite accurate and may do the job for you. BTW that is a
slick idea if it provides the amount of heat you need.

My problem is a lizard that likes to bathe in the mineral oil. Looks like a
7.0 every time he gets into it. Looks like it is time for magnetic damping...


Norman Davis WB6SHI
Shingle Springs, Ca
normd@.............
http://www.directcon.net/normd/index.htm


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From: S-T Morrissey 
Subject: bimetallic thermal comp
Date: Thu, 30 Jul 1998 19:36:06 -0500 (CDT)

re: bimetallic thermal compensation

I have finally implemented plan D for temperature compensation.
This involves extracting the coiled bi-metallic element from a
large cheap dial thermometer, attaching a new central shaft to the
center of the coil (a 0.010 slit in a piece of 1/16" rod, glued
with epoxy), and straightening our about 6cm of the outer
end. 
For a trial installation, the central shaft is clamped to
the boom about 5 cm toward the hinges from the support post, and 
the extended end applies a force to the underside of the 1/4" boom 
clamping bolt. The bimetallic element curls clockwise from the
center, and closes tighter with increasing temperature. So an increase 
in temperature winds up the element, applying less force to the
underside of the support post, allowing the boom to rise. This
compensates for the drop in boom position that results from warming
the main leaf spring. One can test it by breathing on the bimetallic
coil, which makes the boom rise.

Of course, the first evaluation is whether this adversely affects the 
overall performance of the seis. Since the contact of the bimetallic
element with the support post bolt is a metal-metal surface, some
stiction steps might be observed, although I have not seen any. THis
contact will be replaced with a small flexure made with a loop of
nylon thread to allow free differential motion.

To adjust the effectiveness of the compensation, the clamp of the 
central shaft is rotated to apply more or less pressure by the 
free extended end on the fixed bolt.
Since the bimetallic element is actually a temperature dependent spring,
this will increase or decrease the compensation effect.

Does it work? It seems to. I just turned it for more compensation,
and as the box cools off, the DC trend is now negative, indicating
over-compensation. Now I need to log the DC mass position voltage
wrt. temperature to see how effective it is in the long run.
I suppose that to properly adjust it some switchable artificial 
heat source will have to be used, like a small light bulb.

Regards,
Sean-Thomas

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From: taber@............. (John Taber)
Subject: Re: What is the destructive range of an earthquake?
Date: Fri, 31 Jul 1998 12:52:24 +1200



Ashley Neal Hornbeck asked:

>Is there a rule-of-thumb attenuation equation for earthquakes?
>
>In other words:
>If I'm x miles away from the epicenter of M7.0.
>That would be equivalent to being directly above the epicenter of a M y.
>Where:
 >x is distance
 >y is magnitude
>

As Sean-Thomas explained the attenuation varies with tectonic regions, so 
there are a range of attenuation expressions that have been 
determined from different data sets.

An example by Joyner and Boore (1981) for the western US is

log y = -1.02 + 0.249M -log r -0.00255r

where 

y = peak horizontal acceleration in g (decimal fractions of gravity)
r = shortest distance to the fault in km
M = surface wave magnitude

If I've done my algebra right, that means being

10 km away from a magnitude 6 (0.28g) is about the same as being
17 km away from a magnitude 7.  

Cheers,

John 


John Taber		School of Earth Sciences, Victoria University
John.Taber@.............. Box, 600, Wellington, New Zealand


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From: barry lotz 
Subject: Re: bimetallic thermal comp
Date: Thu, 30 Jul 1998 19:40:46 -0700

Sean Thomas
   Thats the best temp compensation device I've heard yet. Simple. I
like it.
                                      Barry

>S-T Morrissey wrote:
> 
> re: bimetallic thermal compensation
> .....

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From: "Al Allworth" 
Subject: RE: bimetallic thermal comp
Date: Thu, 30 Jul 1998 22:19:38 -0700



> -----Original Message-----
> From: S-T Morrissey [mailto:sean@............
> Sent: Thursday, July 30, 1998 5:36 PM
> To: psn-l@.............
> Subject: bimetallic thermal comp
>
>
> re: bimetallic thermal compensation
>


Another thought for the group,

Why not plate copper on one side of the spring. I think this would be the
elegant
solution. Copper plating can be done easily in the home shop / lab and
should be
repeatable once the desired effect is achieved.

								Al


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From: Steve Hammond 
Subject: updated PSN station list
Date: Thu, 30 Jul 1998 22:49:47 -0700

This is the station list with your map ID number is a new listing. All
names without (xx) are new stations added to the list.
This has already been submitted to Steve Malone for the Council of the
National Seismic System Assessment and IASPEI Handbook.
Regards, Steve Hammond 


  Field 1
          Station Operator ID
  Field 2
          Latitude        Longitude
  Field 3
          XXX  see legend  (1st,2nd,3rd charachter
 
  1st charachter
 
          J = Short period <10 seconds
          O = Long-period >10 seconds
          E = Accelerometer
 
  2nd charachter
          S = Short period corner <10 seconds
          B = Broad Band 10 to 89 seconds
          H = smoke / chart recorder >80 seconds
 
  3rd charachter
 
          Number of orientations (ie 1-single channel)


1 NAME:           Al Allworth     W7PXX    (51)      AA1 42.51 -124.33
JS1
2 Name:           Almaden Country Middle School      ACS 37.12 -121.5
OB1
3 NAME:           Albert Judge  (Alby)     (37)      AJ1 -32 115
OB1                                     
4 NAME:           Arie  Verveer            (59)      AV1 -32.0083
116.1346 OB2
5 NAME:           Bob Hammond              (13)      BH1 64.921 -147.937
JH1
6 NAME:           Bob Hammond              (13)      BH2 64.921 -147.937
OH1
7 NAME:           Barry Lotz               (15)      BL1 39.23 -121.07
OB1
8 NAME:           Bill Scolnik             (28)      BS1 41.05 -74.25
JS1                                     
9 NAME:           Bill Scolnik             (28)      BS2 33.5 -74.25
OB2                                    
10 NAME:           Bob Teller               (9)      BT1 46.19 -111.3
OB3
11 NAME:           Charlie Thompson        (10)      BUE 30.112 -97.891
OB2
12 NAME:           Brian Zimmerman         (16)      BZ1 41.875 -80.125
JS1
13 NAME:           Brian Zimmerman         (16)      BZ2 41.875 -80.125
OB2
14 NAME:           Claudio Conti           (58)      CC1 37.035 15.135
OB1
15 NAME:           Claudio Conti           (58)      CC2 37.035 15.135
SJ3
16 Name:           Clark Wockner           (43)      CW1 40.78 -87.75
OB1
17 NAME:           Darrell Collins         (27)      DC1 33.5 -111.9
JS1                                   
18 NAME:           Darrell Collins         (27)      DC2 33.5 -111.9
OB2                                   
19 NAME:           Malcolm Sinclair        (32)      DHQ -45.6 170.4 JH1
20 NAME:           Dennis Leatart           (8)      DL1 34.1 -118.88
JS1
21 NAME:           Douglas McConnell       (49)      DM1 -30.317 149.988
OH1
22 NAME:           Dave Nelson     ZL4TBN   (4)      DN1 -45.8 170.3 JS1
23 NAME:           Dave Nelson     ZL4TBN   (4)      DN2 -45.8 170.3 JS1
24 NAME:           Dave Nelson     ZL4TBN   (4)      DN3 -45.8 170.3 JS1
25 NAME:           Dave Nelson     ZL4TBN   (4)      DN4 -45.8 170.3 OB1
26 Name:           Donald Sieber (retired) (47)      DS1 43.61 -116.21
JS1
27 NAME:           Fred Bruenjes            (2)      FB1 32.822 -117.084
OB1
28 NAME:           Fred Bruenjes            (2)      FB2 32.822 -117.084
OB1
29 NAME:           Frank Cooper    W5VID   (20)      FC1 29.52 -95.17
OB1
30 NAME:           Bob Lewis    WB5FDF     (39)      FD1 33.1 -96.43
OB1                             
31 NAME:           Bob Lewis    WB5FDF     (39)      FD2 33.1 -96.43
JS1                            
32 NAME:           Francesco Nucera        (53)      FN1 -43.29 13.29
OS1
33 NAME:           Francesco Nucera        (53)      FN2 -43.29 13.29
JS2
34 NAME:           Francesco Nucera        (53)      FN2 39.96 -82.98
OB1
35 NAME:           Steve Hammond           (18)      FSX 37.245 -121.815
OB2
36 NAME:           Steve Hammond           (18)      FSZ 37.245 -121.815
JS3
37 NAME:           David Wolny             (34)      GJC 39.079 -108.554
OB1
38 NAME:           Gregory A. Lyzenga       (7)      GL1 34.2 -118.13
OB1
39 NAME:           Giovanni Rotta          (45)      GR1 46.22 13.18 JB1
40 Name:           Grayling School, Alaska           GRY 62.8 -160.1 OH1
41 NAME:           South Valley Jr. High             GS1 37 -121.6 OB1
42 Name:           HSC;  Fairbanks, Alaska           HSC 62.8 -160.1 OH1
43 NAME:           Jeff Batten             (25)      JB1 34.13 -118.12
JS2
44 NAME:           Jeff Batten             (25)      JB2 34.13 -118.12
OB1
45 NAME:           Jeff Batten            (25)       JB3 34.13 -118.12
JH1
46 NAME:           Jean-Jacques Hunsinger (41)       JCH 47.5 7 OB1
47 NAME:           Jerry Darby                       JD1 36.65 -119.3
OB1
48 NAME:           Jim Lovell             (22)       JL1 -43.52 172.61
OS1
49 NAME:           Jack Sandgathe         (23)       JS1 49.35 -119.62
OB1
50 NAME:           Karl Cunningham        (40)       KC1 32.7705
-116.97775 JS1
51 NAME:           Karl Cunningham        (40)       KC2 32.7705
-116.97775 EH1
52 NAME:           Karl Cunningham        (40)       KC3 32.7705
-116.97775 OB1
53 NAME:           Kim Froom                         KF1 34.9 -121.45
OB1
54 NAME:           Ken Navarre            (21)       KN1 37.39 -121.99
OB1
55 NAME:           Kees Verbeek           (12)       KV1 51.26 5.3 JH1
56 NAME:           Larry Cochrane          (1)       LC1 37.496 -122.241
OB1
57 NAME:           Larry Cochrane          (1)       LC2 37.496 -122.241
JS3
58 NAME:           Larry Cochrane          (1)       LC3 37.496 -122.241
OB1
59 NAME:           Lucas Haag             (11)       LH1 40.13 -100.29
JS1
60 NAME:           Tom Frey               (26)       LK1 47.17 -122.49
OB1
61 NAME:           Liberio Rossi          (56)       LR1 43.54 10.34 JS3
62 Name:           Martin S. Brewer       (44)       MB1 32.278 -64.793
OB2
63 Name:           McGrath School, Alaska            MCG 62.9 -155.6 OH1
64 NAME:           Mark Halliday           (5)       MH1 37.085 -122.106
JS1
65 NAME:           Mark Halliday           (5)       MH2 37.085 -122.106
OB1
66 NAME:           Meredith Lamb          (52)       ML1 39.703 -105.006
OB1
67 NAME:           Meredith Lamb          (52)       ML2 39.703 -105.006
OB1
68 NAME:           Meredith Lamb          (52)       ML3 39.703 -105.006
OB1
69 NAME:           Malcolm Sinclair       (32)       MS1 -43.55 172.68
JH1
70 Name:           Pearl Creek School, Alaska        PCK 64.9 -147.8 OH1
71 NAME:           Paolo Frediani         (57)       PF1 44.13 10.06 SJ2
72 NAME:           Paolo Frediani         (57)       PF2 44.13 10.06 OB1
73 NAME:           Pete Rowe                         PR1 37.38 -121.79
JS1
74 NAME:           Robert (Bob) L. Barns   (3)       RB1 40.6802
-74.4142 OB1
75 NAME:           Roger Griggs            (6)       RG1 37.98 -121.72
OB1
76 NAME:           Robert L. Laney        (50)       RL1 38.902 -77.38
OB2
77 NAME:           Charlie Rond           (35)       RM1 35.041 -89.84
OB1
78 NAME:           Roberto E. Pozzo       (38)       RP1 44.46 8.21 OB1
79 NAME:           Roberto E. Pozzo       (38)       RP2 44.46 8.21 JS1
80 NAME:           Roger Sorensen         (19)       RS2 34.2711
-118.59386 JS3
81 NAME:           Dick Webb              (30)       RW1 35.54 -78.39
OB1
82 Name:           Ron Westfall           (42)       RW1 49.325 -122.996
OB2
83 NAME:           Steve Clark            (24)       SC1 44.99 -122.96
JS1
84 NAME:           Phil Giannini          (17)       SFX 37.72 -122.416
OB2
85 NAME:           Phil Giannini          (17)       SFZ 37.72 -122.416
JS1
86 NAME:           Sam Gazdik                        SG1 41.8 -123.2 OB2
87 NAME:           Southland Boys High School (60)   SHS -46.5 168.2 SJ1
88 NAME:           Stephen Mortensen      (55)       SM1 38.828 -120.978
OB1
89 NAME:           Phil Giannini          (17)       SMX 37.75 -122.2
JN3
90 NAME:           Phil Giannini          (17)       SMZ 37.75 -122.2
JN3
91 Name:           SRA,  Fairbanks, Alaska           SRA 62.8 -160.1 OH1
92 NAME:           Peter Styles, Sam Toon (36)       ST1 53.4 -2.96 JS1
93 NAME:           Ted Blank                         TB1 37.21 -121.85
OB1
94 NAME:           Tony Potenzo           (46)       TP1 19.723 -155.991
OB1
95 NAME:           Tony Potenzo           (46)       TP2 19.723 -155.991
JS1
96 NAME:           George Bush            (14)       TSR 38.74 -123.5
EH3
97 NAME:           Phil Giannini          (17)       TVN 37.75 -122.2
OB1
98 NAME:           Phil Giannini          (17)       TVZ 37.75 -122.2
JS1

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From: 
Subject: Geophones
Date: Fri, 31 Jul 1998 11:42:53 EDT

Hello,

Geophones are made in two different configurations, normal and reverse.  The
reverse geophones have the magnet reversed and coil wound in the opposite
direction in reference to the norman phones. They pick up seismic data in the
same phase.  However, any induced emf will be cancelled and therefore 60 hz
power interference is reduced.  They are made to be used in pairs or in an
array, where there will be the same number of normal and reverse geophones.
There is a marking on the geophone element denoting if the geophone is normal
or reversed.

I suggest those of you who are using the MD-81 Geosource vertical phone to use
two phones, one normal and one reverse either connected in parallel or in
series.

Good recordings,

George Erich
GeE777@.......
Seismic Exploration Consultant

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From: Doug Crice 
Subject: Re: Geophones
Date: Fri, 31 Jul 1998 09:25:54 -0700

George:

>From one old sage to another, I have been buying geophones for 25 years
and never heard about normal and reverse geophones.

I believe that modern geophones, including the MD-81, all have "dual
hum-bucking" coils where the geophone has two coils wound to respond to
external fields in equal and opposite polarities so the noise canceling
is internal.

Somebody with a little free time ought to buy a supply of 4.5 Hz phones
from Clark or Mitcham and then resell them individually to the group at
a modest cost.  Since there's so much interest in the 10 Hz phones, 4.5
would be better.  If we're patient, we might buy some 3-component 4.5 Hz
packages cheap.
-- 
Doug Crice          web site http://www.georadar.com
GeoRadar Inc.             e-mail dcrice@............
19623 Via Escuela Drive           phone 408-867-3792
Saratoga, CA 95070 USA              fax 408-867-4900


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From: Greg 
Subject: Re: Geophones
Date: Fri, 31 Jul 1998 10:00:28 -0700

Doug Crice wrote:

> Somebody with a little free time ought to buy a supply of 4.5 Hz phones
> from Clark or Mitcham and then resell them individually to the group at
> a modest cost.  

I checked into a group discount with one company. The volume discount is
well beyond the number of people on the list. Of course, that was just
one company.
I think I lost the original quote from the company, but it might just be
on the other operating system (Windows 95).

OK, I'll bite, who are Clark or Mitcham?

You'd think anyone that can afford to do that would probably just buy
one or two nice commercial instruments for themselves.

,Greg

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From: Doug Crice 
Subject: Re: Geophones
Date: Fri, 31 Jul 1998 10:16:50 -0700

R. T. Clark (405-751-9696) and Mitcham Industries (409-291-2277) are
dealers in used geophysical exploration gear, including seismographs
(exploration), magnetometers, gravimeters, cables, phones, etc.  I'm
sure that neither would welcome orders for individual geophones, but
would be happy to sell a pile of geophones to anybody willing to buy. 
Clark publishes a little flyer once or twice a year which might even
include some 1 Hz phones and an occasional drum recorder, but not at
scrap prices, more like 25 to 50 % of new cost.

They will test the geophones for you.

Seismic crews buy geophones in lots of 5 or 10 thousand, that's why the
quantity discount is our of our reach.  I haven't checked, but I would
guess that a new 4.5 Hz element would cost about $50.
-- 
Doug Crice          web site http://www.georadar.com
GeoRadar Inc.             e-mail dcrice@............
19623 Via Escuela Drive           phone 408-867-3792
Saratoga, CA 95070 USA              fax 408-867-4900


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From: Greg 
Subject: Re: Geophones
Date: Fri, 31 Jul 1998 10:27:37 -0700

Doug Crice wrote:

> guess that a new 4.5 Hz element would cost about $50.

There's one that someone on the list is using. I think it's the GeoSpace
GS-11D. It's about $70 from GeoSpace. They're the ones I asked about the
group discount with.

,Greg

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From: Greg 
Subject: Re: Geophones
Date: Fri, 31 Jul 1998 11:17:31 -0700

Doug Crice wrote:
 
> R. T. Clark (405-751-9696) and Mitcham Industries (409-291-2277) are

I found one anyway ;) http://www.mitchamindustries.com/ 
They have mostly 10Hz geophones from what I saw.

,Greg

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From: Edward Cranswick 
Subject: Re: Use this list -- PSN Station list
Date: Fri, 31 Jul 1998 13:02:57 -0600

Steve-
    That was a labor of love to get all the stations in the list (I
still don't quite grok the instrument description code, but I am working
on it: I downloaded the manual from the IRIS DMC).  Do you have any
thoughts about parts A & C?, i.e.,


> The following items are needed by the end of July:
>
> A.  Network Summary (questionnaire attached below)
> B.  List of stations
> C.  Draft of one paragraph "abstract"
>
I could help you out with something this weekend.
-Edward

Steve Hammond wrote:

> I found a clipped field in the other note--
> please use this list.
>  Steve,
>  PSN Station list attached below
>  Regards, Steve Hammond
>  ---------------------------------
>   Field 1
>           Station Operator
>   Field 2
>           Latitude        Longitude
>   Field 3
>           XXX  see legend  (1st,2nd,3rd charachter
>
>   1st charachter
>
>           J = Short period <10 seconds
>           O = Long-period >10 seconds
>           E = Accelerometer
>
>   2nd charachter
>           S = Short period corner <10 seconds
>           B = Broad Band 10 to 89 seconds
>           H = smoke / chart recorder >80 seconds
>
>   3rd charachter
>
>           Number of orientations (ie 1-single channel)
>



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From: Greg 
Subject: Rip it up or add to it
Date: Fri, 31 Jul 1998 13:12:51 -0700

There was the mention of a web page devoted to geophones as they relate
to PSN a while back. I didn't see anything yet, so I butted in and wrote
a FAQ. I'd appreciate your constructive and destructive comments on it. 

Email me at ghost@.............
The page is at http://www.treefort.org/~ghost/geo.html

It's fairly simple and without pictures. I tested some of the links and
some are from bookmarks. I almost know someone has a few more to add.

Thanks,
Greg

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From: Doug Crice 
Subject: Re: Rip it up or add to it
Date: Fri, 31 Jul 1998 16:33:15 -0700

Greg:

Nice FAQ.

Actually, it's the coil that moves, not the magnet.  You might want to
add a note about frequency response as related to natural frequency, and
mention that they are velocity sensors.

I doubt that Mitchan's web site is an accurate representation of his
inventory.  He's so busy leasing 1000-channel systems and fending off
the lawyers that such things are trivial.  I would give Rory Clark a
call, it's a nice little outfit.
-- 
Doug Crice          web site http://www.georadar.com
GeoRadar Inc.             e-mail dcrice@............
19623 Via Escuela Drive           phone 408-867-3792
Saratoga, CA 95070 USA              fax 408-867-4900



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From: robert barns <75612.2635@..............>
Subject: Re: period/mass etc of STM/ Nitinol actuators
Date: Fri, 31 Jul 1998 20:24:25 -0400

Hi gang,
  Larry Cochrane described in some detail the shaker tabel he built.  He
used a stepper motor.  Look thru the mail archives for this.
Bob Barns

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From: Robert Avakian 
Subject: Re: Geophones
Date: Fri, 31 Jul 1998 19:59:29 -0700

I missed the first post.  The old crews did worry about phone polarity. 
To reduce groundroll and inline noise, the phones were linked in a
series/parallel hookup.  To make sure phones were properly hooked up,
the two leads on each phone were of different widths, one wide, one
narrow.  These fit corresponding takeouts in the cables.  Despite this I
often found strings of phones clipped in backwards. 

I remeber, dimly, some of the companies, such as Pan American supposedly
had their phones wired "backwards" so that even their field records were
reverse polarity from every one else's.

Outside fields meant 60 "cycle" from power lines.  The cables were the
real problem - hroizontal and miles long.  60 Hz "notch" filters were
routinely used in the recording trucks in amy areas as we were
interested in 25 - 80 hz energy.  

Are any seismologists bothered by 60 Hz noise? 



 Doug Crice wrote:
> 
> George:
> 
> >From one old sage to another, I have been buying geophones for 25 years
> and never heard about normal and reverse geophones.
> 
> I believe that modern geophones, including the MD-81, all have "dual
> hum-bucking" coils where the geophone has two coils wound to respond to
> external fields in equal and opposite polarities so the noise canceling
> is internal.
> 
> Somebody with a little free time ought to buy a supply of 4.5 Hz phones
> from Clark or Mitcham and then resell them individually to the group at
> a modest cost.  Since there's so much interest in the 10 Hz phones, 4.5
> would be better.  If we're patient, we might buy some 3-component 4.5 Hz
> packages cheap.
> --
> Doug Crice          web site http://www.georadar.com
> GeoRadar Inc.             e-mail dcrice@............
> 19623 Via Escuela Drive           phone 408-867-3792
> Saratoga, CA 95070 USA              fax 408-867-4900
> 
> _____________________________________________________________________
> 
> Public Seismic Network Mailing List (PSN-L)
> 
> To leave this list email listserver@............. with the body of the
> message: leave PSN-L


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From: Hubert Vroomen 
Subject: short leave
Date: Sat, 01 Aug 1998 11:40:04 +0200

Dear friends,

because I will be away some time the next months, and do not have the
recources for a 1MB e-mail folder, I will leave this very interesting list
for a short period. I hope I will catch up via the archives and expect many
new and interesting things to have happened (Sean-Thomas !) when I
subscribe again (september/october this year or so).

In urgent cases :-) I can be reached under my personal account:
hubert@....................

Thanks alot for the interesting stuff (special thanks to Larry Cochrane for
all his efforts) and good-bye till autumn.

regards,

Hubert


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From: watson@................ (Charles Watson)
Subject: PSN Acknowledged
Date: Sat, 01 Aug 1998 08:54:39 -0700

The PSN was acknowledged in the Opinion section of the July/August 1998 
issue of the Seismological Research Letters.

-- 
---/----
Charles P. Watson
Seismo-Watch

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From: Larry Cochrane 
Subject: Re: PSN Acknowledged
Date: Sat, 01 Aug 1998 13:28:53 -0700

Charles,

Since most of us do not have access to the Seismological Research Letters,
can you tell us what it said?

Thanks,

-Larry Cochrane
Redwood City, PSN

At 08:54 AM 8/1/98 -0700, you wrote:
>The PSN was acknowledged in the Opinion section of the July/August 1998 
>issue of the Seismological Research Letters.
>
>-- 
>---/----
>Charles P. Watson
>Seismo-Watch


_____________________________________________________________________

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From: Edward Cranswick 
Subject: Re: PSN Acknowledged
Date: Sat, 01 Aug 1998 17:25:22 -0600

Larry-
    The article is available at

Interestingly enough, some of the references in it to earthquake prediction,
China and monitoring seismicity using public participation sound similar to
John Lahr's USGS Open-file report of 1978 and the AGU poster that Robert
Banfill and I presented in 1990.  Thanks to Charles Watson for pointing out
the reference.
-Edward

Larry Cochrane wrote:

> Charles,
>
> Since most of us do not have access to the Seismological Research Letters,
> can you tell us what it said?
>
> Thanks,
>
> -Larry Cochrane
> Redwood City, PSN
>
> At 08:54 AM 8/1/98 -0700, you wrote:
> >The PSN was acknowledged in the Opinion section of the July/August 1998
> >issue of the Seismological Research Letters.
> >
> >--
> >---/----
> >Charles P. Watson
> >Seismo-Watch
>
> _____________________________________________________________________
>
> 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".




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From: Edward Cranswick 
Subject: Re: [Fwd: Santa Cruz Seismic Instruction Software]
Date: Sun, 02 Aug 1998 15:53:11 -0600

Ted & Jan -
    I am looking forward to hearing what your plans are for a PSN poster at AGU this
December presented by high school students from Almaden School. Last Thursday, I gave
a short presentation about the PSN to the Education & Outreach (E&O) people from
USGS, and I gave them a handout that was somewhat cosmically connected to the subject
of education; see  ftp://groundmotion.cr.usgs.gov/PSN/PSN_summary.html
    Having a bona fide school connection has always been one of the Holy Grails of
the PSN. Steve Hammond and I were going to do a project with San Jose schools in
1994, but the hiccoughing of the Silicon Valley economy, the Northridge Earthquake,
and school system politics acted together to distract us from that goal.
    I know that you need to talk with the science teacher about the AGU poster, but I
would like a rough draft of the abstract within the next couple of weeks so that I
could run it by the USGS E&O people and get their response and, I hope, support,
before we submit it to AGU (deadline for submission to AGU is the end of August).
    I wish you luck in your preparations.
-Edward

PS. I am having some problems with emailing to the PSN-L, and sometimes I am not sure
whether I am coming or going; so my correspondence may be a trifle incoherent.

Ted Blank wrote:

> I will speak to my son's science teacher.  When I mentioned it to her
> last year she was very excited about the idea.  Thanks for proposing to
> sponsor us.
>
> Ted Blank
> San Jose, California
>
> On Thu, 23 Jul 1998, Edward Cranswick wrote:
>
> >
> >
> > --
> > 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".
> >
> >
>
>   ------------------------------------------------------------------------
>
> Subject: Re: Santa Cruz Seismic Instruction Software
> Date: Thu, 23 Jul 1998 16:47:09 -0600
> From: Edward Cranswick 
> Organization: US Geological Survey, Golden, CO
> To: Jan Froom 
> CC: cranswick@...............
> References: <5030300023233283000002L032*@MHS>
>
> Jan-
>         I thought that you, Steve, and Ted might do something, and I think that
> I forwarded some kind of info to the PSN-L.  However, I was not really
> connected with it myself, and I wasn't going to try to tell you guys
> what you should do (what maybe I should have helped to do myself).  In
> any case, the IRIS meeting does not get as much coverage as the AGU
> meetin in San Francisco in December which Larry and Ted attended last
> year with me.  So I think it would be a great idea to pursue the idea
> that you and Ted talked about last year of having a bunch of students
> submit a poster for the AGU meeting 6-10 December this year
> . You guys can write the
> abstract and prepare the poster and I, as an AGU member, can sponsor it
> and get the USGS to pay for it. The abstract deadline for that is:
>
>         August 26, 1998         (Postal/express mail submissions)
>
>         September 2, 1998       (Interactive Web Form submissions)
>
>         Because we only have about a month, please let me know ASAP what you
> think and also CC a copy to me at  which what
> I am trying to make my address for PSN-related activities.
> -Edward
>
> Jan Froom wrote:
> >
> > It's a shame that we couldn't have gone to this conference, since I think
> > Steve, Ted & I  are about the only ones in this area that are actually working
> > with schools.... well Elementary, Middle & High.  I tried, and got a note from
> > a lady in Arizona that forwarded my request to a lady in Santa Cruz....  but
> > after that I got no answer.
> > ---------------------- Forwarded by Jan Froom/San Jose/IBM on 07-22-98 11:26 AM
> > ---------------------------
> >
> > Ted Blank
> > 07-21-98 01:13 PM
> > To: Jan Froom/San Jose/IBM@IBMUS
> > cc:
> > From: Ted Blank/Santa Teresa/IBM @ IBMUS
> > Subject: Re: Santa Cruz Seismic Instruction Software
> >
> > I tried to get the information from Larry but it was all very vague.  Finally
> > he called me the night before to say it was the next day but by that time I had
> > other plans.  Oh well.
> >
> > Regards, Ted
> > DB2 Performance, IBM Santa Teresa Lab, San Jose, California
> >
> > Ted Blank/Santa Teresa/IBM .....(from Notes)
> > IBMUSM50(TED) .............................(from PROFS/VM)
> > ted@.......... ..............................(from internet sites)
> > STLVM6(BLANK) .............................(for LIST3820 files etc.)
> > Tie: 8-543-3589    Ext:  (408) 463-3589   Fax:  (xxx-2614)
>
> --
> 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".



--
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".




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Public Seismic Network Mailing List (PSN-L)


From: Edward Cranswick 
Subject: test: PSN-L Mailing List 
Date: Sun, 02 Aug 1998 18:29:08 -0600

PSN-L Mailing List 

--
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: test: PSN-L@..............
Date: Sun, 02 Aug 1998 18:30:28 -0600

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: meredith lamb 
Subject: Re: PSN Acknowledged
Date: Mon, 03 Aug 1998 16:00:31 -0600



Edward Cranswick wrote:

> Larry-
>     The article is available at
> 
> Interestingly enough, some of the references in it to earthquake prediction,
> China and monitoring seismicity using public participation sound similar to
> John Lahr's USGS Open-file report of 1978 and the AGU poster that Robert
> Banfill and I presented in 1990.  Thanks to Charles Watson for pointing out
> the reference.
> -Edward
>

Hello Edward,

Indeed it looks like you were busy on the weekend, as you were
the only email traffic on Sunday.

In reference to the above...is there any access to John Lahr's open
file report of 1978?  Of course, if its no longer accessible; the
general message is likely the same I assume.

I commend your never ending efforts to encourage more participation
from the public as a whole.  Earthquakes are of course, not a very
positive subject of interest, as they are dealt with by the media in
terms of death and misery.  This approach often overshadows other
preventative presentations of life and property, which often does not
have the right amount of market share or sales appeal.

As far as prediction efforts, the only point I would care to comment
about, is that the general idea of prediction, should be pinpointed to within
a day of the event...which is a preposterious notion, on the geologic scale of
time.  I would think a plus or minus 5 years would be more of a
bulls eye on a successful prediction, and even here, a additional
century or two leeway, could fall in the success circle zone.  Geological
realism controlls the event, not human timescales.   Parkview and other
sites really deserve a much larger time frame of caution.
............

On a recent TV show, it looks like they are going for the use of
automotive accelerometers in the Los Angeles area...or at least
implied strong interest for their use, as a more distant early warning
system between P & S waves..  Is this approach still in progress,
or is the show out of date?  I believe if my memory serves me right,
that a USGS employee, a Dr. Evans was engaged in this project?

Thanks, Meredith Lamb







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Public Seismic Network Mailing List (PSN-L)


From: meredith lamb 
Subject: Big quake coming in
Date: Tue, 04 Aug 1998 13:55:53 -0600

Hi guys,

See my computer SDR is literally being smeared by a big quake
"somewhere".  Can't even easily follow individual traces.

Hope it is not a killer of people and property.

Meredith Lamb


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Public Seismic Network Mailing List (PSN-L)


From: Marchal van Lare 
Subject: Re: Big quake coming in
Date: Tue, 4 Aug 1998 16:37:01 -0400

Hi all,

This is the first raw data: =


04Aug1998 18:59:07.8  2.6S  81.8W 10 mb=3D6.5 A SED NEAR COAST ECUADOR   =
     1918

source:
http://seismo.ethz.ch/redpuma/redpuma_ami_list.html

Regards,

Marchal van Lare
Nieuwvliet, The Netherlands
 =

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From: meredith lamb 
Subject: Near coast of Ecuador
Date: Tue, 04 Aug 1998 15:06:34 -0600

NEIC says;

98/08/04 18:59:19 Lat 0.47s Long 80.05w  Depth 33.0
Mag 7.1Ms  Near coast of Ecuador

Meredith Lamb




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From: "Walt Williams" 
Subject: PSN-L: Geophone Mounting
Date: Tue, 4 Aug 1998 14:38:49 +0000

Hello All,

I have been experimenting with geophones. 

How are geophones to the connected to amplifier? 

Should the geophone be soldered directly to a an amplifier PCB made 
for that purpose?

Or should the geophone be connected through some short cable/wires to 
the amplifier? 

Thanks in advance.

Walt Williams, 98.08.04
dfheli@..............

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Public Seismic Network Mailing List (PSN-L)


From: "Frank Cooper" 
Subject: Re: Big quake coming in
Date: Tue, 4 Aug 1998 16:58:04 -0500



Hi PSN,
I would like to congratulate John Cole (W5AUH) of Pearland, Texas, USA,
upon receiving his first big earthquake (i.e. 7.1 NEAR COAST OF EQUADOR)
via his newly constructed Lehman seismograph. John called me earlier this
afternoon and asked me if I was receiving something big on my Lehman.  Sure
enough, the pen recorder was hitting the stops on both sides and the signal
was saturating my computer.  The pen on Johns' Esterline-Angus chart
recorder was also hitting the stops on both sides.  We then went on fast
scan amateur television and compared our chart recordings in progress
visually while hopefully many people in the Houston area were watching our
TV broadcast.  My amateur call is W5VID.  We were transmitting on 1.2ghz
and receiving on 70cm (cable channel 57 reception by using an external
antenna) through the Houston Amateur Television Society (HATS) repeater in
downtown Houston, Texas. Several times during the past year and a half I
have broadcast live television pictures of seismograms of an earthquake in
progress.  This may be a first for two live television broadcasts comparing
seismograms of an earthquake in progress.

John has discovered a simple way to dramatically increase the period of a
Lehman.  John will share his discovery on my web site
(http://freeweb.pdq.net/fxc/) with pictures and text within the next day or
two.

Frank Cooper, Friendswood, Texas, USA


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From: "Francesco" 
Subject: BIG QUAKE -    
Date: Wed, 5 Aug 1998 00:55:24 +0200

LARGE P
S in saturation
longe LQ, LR  e T

MS > 7.2

I.E.S.N.  PSN ITALY
Francesco Nucera









LARGE P


S in saturation


longe LQ, LR  e T


 


MS > 7.2


 


I.E.S.N.  PSN =
ITALY


Francesco =
Nucera


From: S-T Morrissey 
Subject: bimetallic thermometer
Date: Tue, 4 Aug 1998 19:57:35 -0500 (CDT)

Barry,

I think that mounting the center of the bimetallic spiral at 
the hinge would probably result in less noise from the 
mechanical arrangement, but would reduce the effect of the 
thermometer, as you observe.  I have the spiral end attached 
to the boom, and the free end applying the correcting force 
to the center boom suppport. I thought of reversing the arrangement,
with the free end contacting the boom near the feedback coil, 
but the bimetallic element is ferrous and is attracted by the 
main magnet. I can reverse the direction, which will allow the
spiral to be mounted to the boom support with a more definitive
method of adjusting the effect (by rotating the center of it).

An easy way to observe the effect of the thermometer is to 
monitor the displacement transducer output and shine a penlight
flashlight (Mini-maglight) on the bimetallic spiral. The heat
of the light will drive the boom up (and off scale) in a few
seconds. A large flashlight will similarly warm the main spring.

The transducer output that you have is a realistic number, but
the transfer function needs the 10x value for the feedback to 
be stable. I do not have any problems with voltage limitations
in normal operation with r= 400 000 volts/meter. The usual
microseismic background runs about 2 to 5 millivolts at the 
VBB output. Todays Mb 7.1 ECUADOR quake peaked at 180 millivolts.
I have the diurnal thermal wander down to about +- 1 volt.
When the feedback is on, the mass movement is reduced by
about 20 to 1 with the Beta instrument.

Regards,
Sean-Thomas

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From: S-T Morrissey 
Subject: geophone info list
Date: Tue, 4 Aug 1998 20:04:39 -0500 (CDT)

I have a flyer here from GEOSWISS GEOPHONE DATA BANK that
proposes a geophone data bank with data on over 3 000
geophones. It is set up for Windows 3.1, 95.
It says it has data, specifications, responses, plots,
etc. at:

http://menbers.aol.com/geophones/geo3.htm

or Geophones@.......

I have not looked at it yet; maybe someone can evaluate it.

Regards,
Sean-Thomas

_____________________________________________________________________

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From: Edward Cranswick 
Subject: Did Clinton feel the Earth move?
Date: Tue, 04 Aug 1998 22:15:52 -0600

Bob-
     Last Thursday (30 July), when I talked to the USGS Education &
Outreach representatives about the PSN, in response to a question about
what kind of ground motions would be felt in Washington DC from
seismicity in Eastern North America, I showed them your record from
Virginia of the earthquake that happened that day in Quebec.
-Edward

Bob Laney wrote:
>
>     ---------------------------------------------------------------
>
>                    Name: 980730a.rl2
>     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".




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From: "Al Allworth" 
Subject: RE: geophone info list
Date: Tue, 4 Aug 1998 23:02:58 -0700

I couldn't get the geophone data list to on AOL to work. The "user"
subaddress
jumps into another url. They must have changed things around. I tried a
search
with no luck.			Al

> -----Original Message-----
> From: S-T Morrissey [mailto:sean@............
> Sent: Tuesday, August 04, 1998 6:05 PM
> To: psn-l@.............
> Subject: geophone info list
>
>
> I have a flyer here from GEOSWISS GEOPHONE DATA BANK that
> proposes a geophone data bank with data on over 3 000
> geophones. It is set up for Windows 3.1, 95.
> It says it has data, specifications, responses, plots,
> etc. at:
>
> http://menbers.aol.com/geophones/geo3.htm
>
> or Geophones@.......
>
> I have not looked at it yet; maybe someone can evaluate it.
>
> Regards,
> Sean-Thomas
>
> _____________________________________________________________________
>
> Public Seismic Network Mailing List (PSN-L)
>
> To leave this list email listserver@............. with the body of the
> message: leave PSN-L
>


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From: Larry Cochrane 
Subject: Re: PSN-L: Geophone Mounting
Date: Wed, 05 Aug 1998 00:02:39 -0700

At 02:38 PM 8/4/98 +0000, Walt wrote:
>Hello All,
>
>I have been experimenting with geophones. 
>
>How are geophones to the connected to amplifier? 
>
>Should the geophone be soldered directly to a an amplifier PCB made 
>for that purpose?
>
>Or should the geophone be connected through some short cable/wires to 
>the amplifier? 

Geophones are usually pretty low impedance (resistance) so you will not
have a problem running a few feet of shielded wire between the sensor and
the amp.

-Larry Cochrane
Redwood City, PSN


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From: "Walt Williams" 
Subject: PSN-L: RE: geophone info list
Date: Wed, 5 Aug 1998 03:41:40 +0000

Hello ST, and All,

The posted URL has a mispelling: 

http://menbers.aol.com/geophones/geo3.htm

the corrected URL:

http://members.aol.com/geophones/geophones.html

homepage:

http://members.aol.com/geophones/geophones.html

Upon visiting the site: the topic appears to be demonstration
software (available for download) which displays information about
geophones from a database. The program allows dynamic modelling of
strings/arrays of geophones. The download version of the database
appears truncated. 

Walt Williams, 98.08.05
dfheli@..............
========================================================



------- Forwarded Message Follows -------
From:          "Al Allworth" 
To:            "PSN-L Mailing List" 
Subject:       RE: geophone info list
Date:          Tue, 4 Aug 1998 23:02:58 -0700
Reply-to:      PSN-L Mailing List 

I couldn't get the geophone data list to on AOL to work. The "user"
subaddress jumps into another url. They must have changed things
around. I tried a search with no luck.			Al

> -----Original Message-----
> From: S-T Morrissey [mailto:sean@............
> Sent: Tuesday, August 04, 1998 6:05 PM
> To: psn-l@.............
> Subject: geophone info list
>
>
> I have a flyer here from GEOSWISS GEOPHONE DATA BANK that
> proposes a geophone data bank with data on over 3 000
> geophones. It is set up for Windows 3.1, 95.
> It says it has data, specifications, responses, plots,
> etc. at:
>
> http://menbers.aol.com/geophones/geo3.htm
>
> or Geophones@.......
>
> I have not looked at it yet; maybe someone can evaluate it.
>
> Regards,
> Sean-Thomas
>
> _____________________________________________________________________
>
> Public Seismic Network Mailing List (PSN-L)
>
> To leave this list email listserver@............. with the body of the
> message: leave PSN-L
>


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From: Arie Verveer 
Subject: Amateur PSN
Date: Wed, 05 Aug 1998 21:39:41 +0800

Hi

Here is one that warms the heart.

For the last 4 months the federal  Governments, local  Geophysical Observatory
(Western Australia) has been sending me a list of  the local, low level seismic events.
This has help immeasurably in identifying the small local events in the data record. So I
responded by sending them the printouts. I then started to wonder if this  might  be
seen as an "amateur irritant",  so I contacted the people involved and asked the
question "Do you really want this stuff". There answer was yes.
So there is a small place for the amateur in the local events. That warms the heart.

Arie.


Then again they may need the printouts to line the bottom of the "parrots" cage. ?



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From: Edward Cranswick 
Subject: Re: Amateur PSN
Date: Wed, 05 Aug 1998 11:58:03 -0600

Arie-
    One of these days maybe the USGS will want some data from the PSN. Just after and because
of the PSN AGU presentation last December, I did get a request for PSN records of local
events in the San Francisco Bay Area from a seismologist from University of California
Berkeley, but at the time I was not able to to find suffiicient unclipped data from
well-behaved instruments.
    On the other hand, as they say in California (or as some said back in the 1960's): "Every
day in every way, better and better".
-Edward

Arie Verveer wrote:

> Hi
>
> Here is one that warms the heart.
>
> For the last 4 months the federal  Governments, local  Geophysical Observatory
> (Western Australia) has been sending me a list of  the local, low level seismic events.
> This has help immeasurably in identifying the small local events in the data record. So I
> responded by sending them the printouts. I then started to wonder if this  might  be
> seen as an "amateur irritant",  so I contacted the people involved and asked the
> question "Do you really want this stuff". There answer was yes.
> So there is a small place for the amateur in the local events. That warms the heart.
>
> Arie.
>
> Then again they may need the printouts to line the bottom of the "parrots" cage. ?
>
> _____________________________________________________________________
>
> 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".




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From: 
Subject: Re: Did Clinton feel the Earth move?
Date: Wed, 5 Aug 1998 16:54:17 EDT

Edward--

Interesting!  Glad my record of the Quebec event was of use.  Now, if the one
yesterday in Ecuador had been available for your discussions--it was a dandy.

Bob

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From: "Frank Cooper" 
Subject: simple way to increase the period of a Lehman
Date: Wed, 5 Aug 1998 22:01:42 -0500


Hi,
I have posted pictures and text on my home page illustrating John Cole's
(W5AUH) simple way to increase the period of a Lehman.  There may be slight
changes in the text during the next day or two.
Frank Cooper (W5VID), 
Friendswood, Texas, USA


> John has discovered a simple way to dramatically increase the period of a
> Lehman.  John will share his discovery on my web site
> (http://freeweb.pdq.net/fxc/) with pictures and text within the next day
or
> two.
> 
> Frank Cooper, Friendswood, Texas, USA



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From: bob ogburn 
Subject: EW activity for 40 Min.
Date: Wed, 05 Aug 1998 20:13:53 -0700

About 40 min. ago, strong East-West motion here. Still moving.



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From: Gregory Bajuk 
Subject: 16 bit Audio A/D cards
Date: Wed, 5 Aug 1998 21:34:13 -0700 (PDT)

Since most computer audio cards can convert music/voice/sound input to a
digital .wave file, can these cards be used to record and display
seismograph files as well.  Has anyone tried this? If so please reply with
your experiences.  Thanks.
Greg Bajuk


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Public Seismic Network Mailing List (PSN-L)


From: Greg 
Subject: Re: 16 bit Audio A/D cards
Date: Wed, 05 Aug 1998 22:24:20 -0700

Gregory Bajuk wrote:

> seismograph files as well.  Has anyone tried this? If so 

I was very disappointed to see this message, but since it's out there...
I wanted to see how far I could get with it and announce it to the list
if it was a major breakthrough or something.

I just tried this today. I have often thought of it since I first saw
the cost of DA cards. I have a geophone connected to the line in on my
sound card right now. I was playing around with jumping up and down and
beating the floor with my fist and I finally noticed the gain on the
line in was set to half. I have a gif file with about six signals from
me pounding my heal on the carpet. It doesn't look too bad until you
consider that I was about 2 feet away and I had to amplify the signal
the equivalent of 14 times the original. I'm going to try the microphone
again soon.

One of the main things I wanted to do on the internet tonight was look
into writing or finding software for it. I've been playing with some
software called HamView lately and I managed to see some signals in that
also. It's very neat software, if there are any hams on the list. I can
see all kinds of noise and satellites and ... There's a similar program
that requires registration and doesn't seem to show as much called
FFTDSP4.2 or something similar.

If I can't find the software I'd like to find some C function that
allows you to retrieve the signal from either input source on the sound
card. One thing to consider is that I think the voltage range for the
line in is +- 2V? I think the Larry C. board is +- 5V? It might need a
different preamp than the Larry C. because of the voltage difference,
but I'm not an electronics wiz.

,Greg

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From: David Josephson 
Subject: Re: 16 bit Audio A/D cards
Date: Wed, 5 Aug 1998 23:29:28 -0700 (PDT)

Most of the computer sound cards roll off below a few tens of
Hz. They use delta-sigma analog to digital converters that are
fine for audio, but don't give very good performance in the 
0.01 - 10 Hz range you need.

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From: Steve Hammond 
Subject: [Fwd: LAte late PSN additions]
Date: Wed, 05 Aug 1998 22:56:53 -0700

RPC is Dick Chelberg
BK1 is Bruce Kinney
GC1 is Jan Froom

I mist have not saved the data at some point because I did add them at
one point. 
Thanks for bringing it to my attention.

Regards, Steve Hammond
Steve An error was just brought to my attention. I missed three of the
main PSN stations in the survey... can you add them?
Thanks-- Steve Hammond

RPC 37.24 -121.845 OB1 PSN
BK1 37.24 -121.839 OB1 PSN
GC1 37.5 -126.1 OB2 PSN

From: "David A. Nelson" 
Subject: Re: EW activity for 40 Min.
Date: Thu, 06 Aug 1998 19:48:58 +1200

At 08:13 PM 8/5/98 -0700, you wrote:
>About 40 min. ago, strong East-West motion here. Still moving.

bob  where are u   ??

 what was the universal time (UTC)  ??


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


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From: Edward Cranswick 
Subject: Re: Near coast of Ecuador
Date: Thu, 06 Aug 1998 03:05:48 -0600

Meredith-
    Though I have not yet responded to your previous message, I wanted to
look at some of your vector (three-component) records of the Ecuador event
before they became too stale.

    ftp://groundmotion.cr.usgs.gov/PSN/lamb/980804/VEC18V.GIF
is 18 minutes of the three components of velocity as recorded and plotted
to the same amplitude scale.
    1 000/000  =  Z
    2 090/000  =  N
    3 090/090  =  E
    [There are two spherical-coordinate values in degrees, separated by a
'/',
    that define the direction of positive ground motion of each orthogonal

    component. The first value is the zenith angle, i.e., the inclination
measured
    from the zenith, i.e., 000/ = vertical-up, and 090/ = horizontal.
    The second value is the azimuth measured clockwise from North,
    i.e., /000 = North, and /090 = East]
Note that the P phase is somewhat larger on the vertical component (Z)
than on the horizontal components (N, E) and that the S and SS&SSS phases
are much larger on the horizontals than on the vertical.  Also note that
the amplitudes of corresponding P and S phases on both horizontals are
roughly equal.

    ftp://groundmotion.cr.usgs.gov/PSN/lamb/980804/VEC18VR.GIF
is the same as the previous plot (the amplitude scale has been changed by
about 15%) except that the N and E horizontal components have been rotated
respectively into the radial (R) and tangential (T) orientations with
respect to the direction at the receiver (station) of waves propagating
away from the source (epicenter). This radial direction away from the
source as measured at the receiver is the opposite (+/-180 degrees) of the
"Station to Event Azimuth: 144.1 degrees" calculated by WinQuake 2.5.2 for
this station/earthquake pair. Hence:
    1 000/000  =  Z
    2 090/324  =  R
    3 090/054  =  T
Note that the different phases have now been differentially partitioned
between the horizontal components. The P phases are virtually absent on
the T component (as they should be in theory), and nearly all of the
P-wave energy is on the R component. The S phase appears to be different
on the R & T components, and the SS&SSS phases are strong on T but weak on
R.

    I have done more analysis of this vector record and hope to put some
more of it out on the Web.
-Edward

meredith lamb wrote:

> NEIC says;
>
> 98/08/04 18:59:19 Lat 0.47s Long 80.05w  Depth 33.0
> Mag 7.1Ms  Near coast of Ecuador
>
> Meredith Lamb
>
> _____________________________________________________________________
>
> 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".




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From: robert barns <75612.2635@..............>
Subject: EW activity for 40 Min.
Date: Thu, 6 Aug 1998 09:45:31 -0400

Where is "here" ?
Bob Barns

Quantum Mechanics--The dreams stuff is made of.

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From: Steve Hammond 
Subject: Re: EW activity for 40 Min.
Date: Thu, 06 Aug 1998 06:56:17 -0700

Bob lives in the San Francisco Bay area.

robert barns wrote:
> 
> Where is "here" ?
> Bob Barns
> 
> Quantum Mechanics--The dreams stuff is made of.
> 
> _____________________________________________________________________
> 
> Public Seismic Network Mailing List (PSN-L)
> 
> To leave this list email listserver@............. with the body of the
> message: leave PSN-L

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From: Greg 
Subject: Re: 16 bit Audio A/D cards
Date: Thu, 06 Aug 1998 09:53:57 -0700

David Josephson wrote:

> 0.01 - 10 Hz range you need.

When you consider that the geophone is a 10 Hz geophone and it's an
almost free setup, I still think it's worth pursuing.

I've been reading about the hardware level programming and it would
appear so far to be restricted to recording at a minimum of 4-5 KHz. I'm
going to check some more and it might be easy to just strip out most of
the data as it's recorded to disk. If not the disk would have to be
pretty darn big.

,Greg

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From: meredith lamb 
Subject: Vector Analysis of ML Sprengnether S5000 set
Date: Thu, 06 Aug 1998 11:56:17 -0600

Hi Edward,

Thanks for your time and effort of the analysis of 8/6/98.  I'll be
looking forward to seeing the afore mentioned upcoming additional
data in the future.

Am assuming that the current part only shows the difference in
horizontals response, and outside of variables like damping and
amplifier differences there may not be much more, that can be
done to attain a more equitable response.

Outside of the generious time for the above:

I would also be very interested in your accessment of the the normal
N-S (ML2), versus, the ML4 experimental Hall sensor phase/frequency
responses, which is on the same boom of the ML2, Ecuador quake dated
8/4/98.

The time that Robert Lamb and I have put into the sensor has been
substantial, and it currently is of very strong interest, for possible
ongoing continuing improvement.  Eventually I hope to throw on these
sensors on all 3 components, for comparisons of the Hall v/s the
normal velocity coils.  Would appreciate even a very rough appraisal
as I lack everything compared to your experience/equipment.  I do have
the unprocessed files if you are that interested, which I can forward
via email or regular mail. To say the least; I think they have alot
of potential for seismic use or even velocity coil sensor replacement,
but that is just my opinion.  Any eventual results will be public use
or disclosure of course.  Am also assuming this is not new stuff, but,
I've heard or seen zero on Hall sensor seismic use, outside of
Albert Judge of England. 

Thanks, Meredith Lamb


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From: "Steve Carniglia" 
Subject: Re: 16 bit Audio A/D cards
Date: Thu, 6 Aug 1998 11:14:57 -0700

Yes...........quite a bit of fooling around with this and yes it works but
getting the data to conform to the standard is a REAL challenge......there
is a bunch of free software on the internet that will allow you to watch the
data.....

Best Regards
Steve



-----Original Message-----
From: Gregory Bajuk 
To: PSN-L@............. 
Date: Wednesday, August 05, 1998 9:37 PM
Subject: 16 bit Audio A/D cards


>Since most computer audio cards can convert music/voice/sound input to a
>digital .wave file, can these cards be used to record and display
>seismograph files as well.  Has anyone tried this? If so please reply with
>your experiences.  Thanks.
>Greg Bajuk
>
>
>_____________________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email listserver@............. with the body of the
>message: leave PSN-L


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From: "Steve Carniglia" 
Subject: Re: 16 bit Audio A/D cards
Date: Thu, 6 Aug 1998 11:16:56 -0700

Yes there is lots of this stuff out there.....I have experimented with a
bunch of it....

Best Regards  or as we say in the ham world, 73

Steve   KV6A




-----Original Message-----
From: Greg 
To: PSN-L Mailing List 
Date: Wednesday, August 05, 1998 10:30 PM
Subject: Re: 16 bit Audio A/D cards


>Gregory Bajuk wrote:
>
>> seismograph files as well.  Has anyone tried this? If so
>
>I was very disappointed to see this message, but since it's out there...
>I wanted to see how far I could get with it and announce it to the list
>if it was a major breakthrough or something.
>
>I just tried this today. I have often thought of it since I first saw
>the cost of DA cards. I have a geophone connected to the line in on my
>sound card right now. I was playing around with jumping up and down and
>beating the floor with my fist and I finally noticed the gain on the
>line in was set to half. I have a gif file with about six signals from
>me pounding my heal on the carpet. It doesn't look too bad until you
>consider that I was about 2 feet away and I had to amplify the signal
>the equivalent of 14 times the original. I'm going to try the microphone
>again soon.
>
>One of the main things I wanted to do on the internet tonight was look
>into writing or finding software for it. I've been playing with some
>software called HamView lately and I managed to see some signals in that
>also. It's very neat software, if there are any hams on the list. I can
>see all kinds of noise and satellites and ... There's a similar program
>that requires registration and doesn't seem to show as much called
>FFTDSP4.2 or something similar.
>
>If I can't find the software I'd like to find some C function that
>allows you to retrieve the signal from either input source on the sound
>card. One thing to consider is that I think the voltage range for the
>line in is +- 2V? I think the Larry C. board is +- 5V? It might need a
>different preamp than the Larry C. because of the voltage difference,
>but I'm not an electronics wiz.
>
>,Greg
>
>_____________________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email listserver@............. with the body of the
>message: leave PSN-L


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From: "James M Hannon" 
Subject: Re: 16 bit Audio A/D cards
Date: Thu, 6 Aug 1998 13:15:21 -0500






Greg  on 08/06/98 11:53:57 AM

Please respond to PSN-L Mailing List 

To:   PSN-L Mailing List 
cc:
Subject:  Re: 16 bit Audio A/D cards




I've been reading about the hardware level programming and it would
appear so far to be restricted to recording at a minimum of 4-5 KHz. I'm
going to check some more and it might be easy to just strip out most of
the data as it's recorded to disk. If not the disk would have to be
pretty darn big.

,Greg



Greg,

I did a little looking and it appears that you are limited to 4KHz minimum
      sample rate by the hardware.  It would be easy enough to throw away
      samples and only keep every Nth sample. This will work fine as long
      as you have some external anti aliasing filter in your setup.

I have been considering using the sound card in a laptop to record geophone
      outputs to do a little seismic exploration with geophones and a large
      hammer. Haven't found the time to persue it though. :)



Jim Hannon




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Public Seismic Network Mailing List (PSN-L)


From: "James M Hannon" 
Subject: Re: Near coast of Ecuador
Date: Thu, 6 Aug 1998 13:18:42 -0500

Edward,
Thanks for showing us your analysis of the 3 axis data.  I had been
wondering what sort of usefull information could be extracted if you had 3
axis data avaliable.  This will be very usefull when I get my three axis
instrument running.

Jim Hannon



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From: Pinpoint 
Subject: Re: 16 bit Audio A/D cards
Date: Thu, 06 Aug 1998 11:51:34 -0700

At 11:16 AM 8/6/98 -0700, Steve Carniglia wrote:
>Yes there is lots of this stuff out there.....I have experimented with a
>bunch of it....
>
>Best Regards  or as we say in the ham world, 73

Perhaps I am misreading what this thread is all about.
  We use graphics to demonstrate trends in a way that many people can
understand. In that same sense if we were able to 'hear' the trace besides
just seeing it, what an interesting thing that might be for some.
  If it were a simple cut and paste from the trace onto something such as
Soundblaster or Goldwave....but none of those manufactures allow for
graphics to digital. What about raw data? Would be very easy to convert raw
data into sound .wav files
.. I have done something similar to that in the past, but knew about the
media with which I was working. If someone would be willing to send me a
raw data file with simple explanation and trace gif, I would be willing to
write a conversion program to SB/GUS digital standards...
Bob

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From: lahr@..................
Subject: All Electronics Corp. Geophones
Date: Thu, 6 Aug 1998 13:12:07 -0600 (MDT)

This is from the back page of the All Electronics Corp. 
catalog #496, which is the one available in PDF format on
the web.

JCLahr

INTERNET USERS!
Visit Our WWW Site
http://www.allcorp.com
E-Mail us at
allcorp@...........
California Store Locations
905 S. Vermont Avenue
Los Angeles, 90006
(213) 380-8000
14928 Oxnard Street
Van Nuys, 91411
(818) 997-1806
BULK RATE
US POSTAGE
PAID
ONTARIO, CA
PERMIT # 12
A AL LL L
E EL LE EC CT T R R O ON NI I C CS S
C O R P O R AT I O N

GEOPHONE -
VIBRATION SENSOR
Extremely sensitive to all kinds of
vibration, from a tiny tap on a table to
a truck driving by in the street. These
Geophones were used in oil exploration to
gather geological statistics. They can be used as
seismic detectors or shock detectors in alarm systems.
Inside is a magnet suspended in a coil which
generates an electrical current capable of lighting an
LED. Natural frequency: 10Hz. We supply a couple
of simple circuit diagrams which allow you to monitor
and harness the Geophone's response. 1.6" high x
1.2" diameter. These are
functioning used units.
CAT # GP-1

> From: Woolf Kanter 
> Subject: Re: Geophone on sale
> 
> Meredith,
> 
> The geophones are made by Geosource Inc., Model # MD-81.  They were
> manufactured in 1985 and appear to have been used.  They measure 616 ohms
> across the coil.
> Guaranteed functional.  That's all we know.
> 
> All Electronics Corp
> 

Actually the coil is suspended in the field of a magnet.

JCLahr

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From: "James M Hannon" 
Subject: Re: 16 bit Audio A/D cards
Date: Thu, 6 Aug 1998 14:15:51 -0500






Pinpoint  on 08/06/98 01:51:34 PM

Please respond to PSN-L Mailing List 

To:   PSN-L Mailing List 
cc:
Subject:  Re: 16 bit Audio A/D cards




Perhaps I am misreading what this thread is all about.
  We use graphics to demonstrate trends in a way that many people can
understand. In that same sense if we were able to 'hear' the trace besides
just seeing it, what an interesting thing that might be for some.
  If it were a simple cut and paste from the trace onto something such as
Soundblaster or Goldwave....but none of those manufactures allow for
graphics to digital. What about raw data? Would be very easy to convert raw
data into sound .wav files
.. I have done something similar to that in the past, but knew about the
media with which I was working. If someone would be willing to send me a
raw data file with simple explanation and trace gif, I would be willing to
write a conversion program to SB/GUS digital standards...
Bob

Bob,
The thread is about recording the output of either geophones or a
seismograph with a sound card rather than listening to the recorded data.

Listening to a data file is fairly easy. I have converted one of Larry's
recordings into a .au file and put it on the web at
http://soli.inav.net/~jmhannon/seismology.html click on "listen to an
earthquake" if you have a browser set up to play .au files.


Jim Hannon




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From: "Phil Giannini" 
Subject: Earthquake Lists
Date: 6 Aug 1998 13:08:03 -0800

Mail*Link(r) SMTP               Earthquake Lists


Hello Fellow Enthusiasts,
    Not too very long ago there was a great website that had a complete
archive listing of past earthquakes. It was designed in a calendar-like
format where you could click on a date and get a listing of all the more
significant quakes for that particular day. The location was:
   http://www.cdidc.org:65120/web-bin/bulldaily/calendar=yes/bulletin=GAMMAs

   I get a "no such URL" message when I try that location now. My question is,
does anyone know what happened to that website and is there something
similar to that around anymore. Any input will be appreciated.

                                        Thanks, Phil  SFN&Z



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From: S-T Morrissey 
Subject: VCO into sound card
Date: Thu, 6 Aug 1998 15:20:52 -0500 (CDT)

Re. Sound cards

For input to a PC sound card, we have considered the possibility 
of using a VCO (voltage controlled oscillator) IC after the 
seismometer pre-amp to convert the seismic signal into an FM audio 
tone whose frequency change is proportional to the input voltage. 
We use this FM-VCO method in all the analogue telemetry that we do, 
since it allows us to transmit the near DC seismic signal over VHF 
radio links and standard telephone lines. With 10 VCO center frequencies, 
each deviating +- 125 hz for a +- 2 volt input, we can get ten 
seismic stations on one RF link or phone line.
(for reference, we use a preamp gain of 72db, or x 4 000, on the
output of an L4-C seismometer with a 5500 ohm coil at 270 V/M/sec.)

This audio VCO would get the seismic input into the passband of 
the sound card. THere is software that can read the instantaneous 
frequency value, which would have to be sampled at some moderate 
rate and written to a buffer. To recover the seismic signal, a 
digital "discriminator" would compare the instantaneous FM frequency 
with the VCO referenced center frequency, the difference being the
seismic voltage in volts/hz, which is 16 mv/hz with our VCOs.
With oversampling, the difference could be determined with a phase
resolution of 45 degrees or better, which, with a +- 125 hz deviation, 
would allow a dynamic range of 1000 or 60 db, or about 10 bits of
resolution. Of course, the VCO span could be increased by a factor of
10 or more, like 2 khz +- 1250 hz, to get a dynamic range of 
10 000, or 80 db, or 13 to 14 bits.

With the dynamic range needed for seismometer data, 10 bits is
not really enough; our lowest resolution for network data is 16 bits
and the broadband stations have 24 bit ADCs.

Regards,
Sean-THomas


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From: Canie Brooks 
Subject: Re: Earthquake Lists
Date: Thu, 06 Aug 1998 13:18:41 -0700

Try this:
http://www.cmr.gov/web-bin/recentevents

canie

At 01:08 PM 8/6/98 -0800, Phil Giannini wrote:
>Mail*Link(r) SMTP               Earthquake Lists
>
>
>Hello Fellow Enthusiasts,
>    Not too very long ago there was a great website that had a complete
>archive listing of past earthquakes. It was designed in a calendar-like
>format where you could click on a date and get a listing of all the more
>significant quakes for that particular day. The location was:
>   http://www.cdidc.org:65120/web-bin/bulldaily/calendar=yes/bulletin=GAMMAs
>
>   I get a "no such URL" message when I try that location now. My question
is,
>does anyone know what happened to that website and is there something
>similar to that around anymore. Any input will be appreciated.
>
>                                        Thanks, Phil  SFN&Z
>
>
>
>_____________________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email listserver@............. with the body of the 
>message: leave PSN-L
> 

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From: Pinpoint 
Subject: Re: 16 bit Audio A/D cards
Date: Thu, 06 Aug 1998 13:29:05 -0700

At 02:15 PM 8/6/98 -0500, James M Hannon wrote:

>Bob,
>The thread is about recording the output of either geophones or a
>seismograph with a sound card rather than listening to the recorded data.
>
>Listening to a data file is fairly easy. I have converted one of Larry's
>recordings into a .au file and put it on the web at
>http://soli.inav.net/~jmhannon/seismology.html click on "listen to an
>earthquake" if you have a browser set up to play .au files.


Jim and others;
  Thanks so much for clarifying! So...What method are you or others using
to 'hear' the earthquake? Would some of you who know or have this software
please share other earthquake sounds. I believe I may have had an intuitive
thought on this sounds at PSN which you directed me to.
  In OW...anyone with EQ sounds, please send them to me as attachments. I
noticed the .au file was not very long so attachments should not be a
problem in either direction...
  FYI Netscape is set-up to hear .au sounds as long as one has a sound card
and knows how to configure NS.
Bob


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From: David Josephson 
Subject: Re: VCO into sound card
Date: Thu, 6 Aug 1998 14:25:31 -0700 (PDT)

Sean-Thomas writes

> For input to a PC sound card, we have considered the possibility 
> of using a VCO (voltage controlled oscillator) IC after the 
> seismometer pre-amp to convert the seismic signal into an FM audio 
> tone whose frequency change is proportional to the input voltage. 
> We use this FM-VCO method in all the analogue telemetry that we do, 

This makes good sense to me. It would also be a way to get many 
seismic signals into a cheap computer at once. For example, several
axes of geophones, and one or more long period instruments (perhaps
with different deviation limits according to the s/n required). Then
it would not be difficult to expand the software mentioned:

> the sound card. THere is software that can read the instantaneous 
> frequency value, which would have to be sampled at some moderate 
> rate and written to a buffer. To recover the seismic signal, a 

The limitations on s/n mentioned

> would allow a dynamic range of 1000 or 60 db, or about 10 bits of
> resolution. Of course, the VCO span could be increased by a factor of
> 10 or more, like 2 khz +- 1250 hz, to get a dynamic range of 
> 10 000, or 80 db, or 13 to 14 bits.

can be further expanded, as a typical sound card will record at
44.1 kHz stereo, which is about 40 kHz of bandwidth (20-20kHz,
times two channels)

While the sampling rate would be high, the software could reduce
this to baseband at the desired data rate before sending it to disk.


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From: Arie Verveer 
Subject: Re: Earthquake Lists
Date: Fri, 07 Aug 1998 00:29:22 +0800

Hi Phil

I know what you mean, I used the list often. So armed with
bull dogged determination, it was tracked down to :

http://www.pidc.org/dataprodbox/prod.html

Regards

Arie


Phil Giannini wrote:

> Mail*Link(r) SMTP               Earthquake Lists
>
> Hello Fellow Enthusiasts,
>     Not too very long ago there was a great website that had a complete
> archive listing of past earthquakes. It was designed in a calendar-like
> format where you could click on a date and get a listing of all the more
> significant quakes for that particular day. The location was:
>    http://www.cdidc.org:65120/web-bin/bulldaily/calendar=yes/bulletin=GAMMAs
>
>    I get a "no such URL" message when I try that location now. My question is,
> does anyone know what happened to that website and is there something
> similar to that around anymore. Any input will be appreciated.
>
>                                         Thanks, Phil  SFN&Z
>
> _____________________________________________________________________
>
> Public Seismic Network Mailing List (PSN-L)
>
> To leave this list email listserver@............. with the body of the
> message: leave PSN-L




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From: bob ogburn 
Subject: Re: EW activity for 40 Min.
Date: Thu, 06 Aug 1998 19:49:41 -0700

Sorry....

here= 37.67704 -122.47334
when= 0358 6Aug98 Z
what= local construction (piledriving at SFO)



David A. Nelson wrote:

> At 08:13 PM 8/5/98 -0700, you wrote:
> >About 40 min. ago, strong East-West motion here. Still moving.
>
> bob  where are u   ??
>
>  what was the universal time (UTC)  ??
>
> 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)
>
> To leave this list email listserver@............. with the body of the
> message: leave PSN-L




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From: taber@............. (John Taber)
Subject: PSN and schools
Date: Fri, 7 Aug 1998 16:08:34 +1200


Edward,

You wrote:

>Having a bona fide school connection has always been one of the Holy 
>Grails of the PSN. 

Perhaps we can help with that connection.  We have started a school
seismic network here in New Zealand, and you can visit the beginnings
of our Quake Trackers home page at 
http://www.geo.vuw.ac.nz/seismology/Quake_Trackers/.

We are getting off the ground with the considerable help of Larry 
Cochrane and Dave Nelson and others including local teachers
and students, and with initial funding from the NZ 
Earthquake Commission (the national earthquake insurance company for
NZ).  We are using Larry's A/D board and software and 
the 4.5 Hz geophones that Dave has shown are effective at picking
up NZ seismicity.  Following Dave's lead in the South Island
(at Alan Munro's Southland Boys High School) 
we have installed a seismograph at the first of
the 5-6 schools we plan to have set up in the Wellington region
by the end of the year.   The plan is to add at least 5-6 schools per 
year.

We are mirroring PEPP's curriculum pages with
slight modifications to make them more applicable to NZ.  We
are also working with Larry and local teachers to develop activities 
based around WinQuake.

Any comments and suggestions for the web site are most welcome.

We will be storing the data on our web site since the data
will be primarily for local events, but it will be stored in
PSN format so all WinQuake users will be able to access it.
The database should be up before the end of the month.

I've followed your efforts ever since I was shown your first PSN AGU 
abstract, and have wanted to get involved in some way but never seemed 
to have sufficient time and/or funding.  Now through global
cooperation it all seems to be comming together.

Do you know if there is going to be a session on seismology
education in schools at AGU this year, and do you think it would be
worthwhile for us to submit an abstract?  I wasn't initially
planning to come this year (it's a long way from NZ) but if you
think there would be sufficient interest, I think I could
arrange it.


Regards,

John 



John Taber		School of Earth Sciences, Victoria University
John.Taber@.............. Box, 600, Wellington, New Zealand

phone: +64-4-472-1000
fax:   +64-4-495-5186


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From: Herald Gessinger 
Subject: Re: 16 bit Audio A/D cards
Date: Fri, 07 Aug 1998 08:34:54 +0200

Hi Greg,

I had a similar idea, but I think it is necessary to use the quake signal as a
modulation signal of a 1000 cps carrier. This can easily be done by some
analog circuitry with a frequency modulation chip. The sound card will produce
a *.wav file with the modulated 1000 cps tone.

But I stopped here with the problem to translate the stored FM signal into a
quake file. My mathematical background and my programming knowledge is too low
to write such a converter program. Is anybody here in the list with more
experience?

Herald Gessinger
Austria/Europe
h.gessinger@.........

Gregory Bajuk wrote:

> Since most computer audio cards can convert music/voice/sound input to a
> digital .wave file, can these cards be used to record and display
> seismograph files as well.  Has anyone tried this? If so please reply with
> your experiences.  Thanks.
> Greg Bajuk
>
> _____________________________________________________________________
>
> 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: 16 bit Audio A/D cards (DSP 101)
Date: Fri, 7 Aug 1998 07:47:03 -0500






Herald Gessinger  on 08/07/98 01:34:54 AM

Please respond to PSN-L Mailing List 

To:   PSN-L Mailing List 
cc:
Subject:  Re: 16 bit Audio A/D cards




Hi Greg,

I had a similar idea, but I think it is necessary to use the quake signal
as a
modulation signal of a 1000 cps carrier. This can easily be done by some
analog circuitry with a frequency modulation chip. The sound card will
produce
a *.wav file with the modulated 1000 cps tone.

But I stopped here with the problem to translate the stored FM signal into
a
quake file. My mathematical background and my programming knowledge is too
low
to write such a converter program. Is anybody here in the list with more
experience?

Herald Gessinger
Austria/Europe
h.gessinger@.........



There are about as many ways to do this as there are DSP designers.  Here
      is the approach I would take.

Complex mix the signal down to DC.  To do this you multiply the data
      samples by the sin and cos of 1000 Hz.  The resulting sample pairs
      are called  I and Q for Inphase and Quadurature. At this point the FM
      signal is centered around DC rather than 1000 Hz so you can clean it
      up a little by running it through a FIR low pass filter.  Now the
      frequency of the signal is represented by how fast the vector
      represented by the I and Q signals rotates.  If your original signal
      was at 1000 Hz the vector would not rotate at all. For frequencies
      (in the original signal) above 1000 Hz the vector will rotate in one
      direction and for frequencies below 1000 Hz the vector will rotate in
      the opposite direction. To compute the frequency you calculate the
      angle represented by each successive vector and then subtract the
      angles of successive samples.  This difference in angles represents
      the frequency of the signal or in our case the original voltage out
      of the seismograph. The sign of the voltage is indicated by which way
      the vector is rotating so we recover our original plus or minus
      voltage signal.  At this point you need to run the demodulated
      samples through a decimation filter to get the sample rate down to
      something in line with the original seismic waveform frequency
      response and store the data as a PSN file.

Jim Hannon




_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: Norman Davis WB6SHI 
Subject: Re: VCO into sound card
Date: Fri, 07 Aug 1998 07:09:02


>> For input to a PC sound card, we have considered the possibility 
>> of using a VCO (voltage controlled oscillator) IC after the 
>> seismometer pre-amp to convert the seismic signal into an FM audio 
>> tone whose frequency change is proportional to the input voltage. 
>> We use this FM-VCO method in all the analogue telemetry that we do, 

We are already doing this... I run my lehman into an xr chip and then into
the sound card and view it on fftdsp software. Also remote sites of usgs
can be heared on vhf radio and mixed into the soundcard and viewed at the
same time.


Norman Davis WB6SHI
Shingle Springs, Ca
normd@.............
http://www.directcon.net/normd/index.htm


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: Norman Davis WB6SHI 
Subject: Re: 16 bit Audio A/D cards
Date: Fri, 07 Aug 1998 07:15:21

At 09:34 PM 8/5/98 -0700, you wrote:
>Since most computer audio cards can convert music/voice/sound input to a
>digital .wave file, can these cards be used to record and display
>seismograph files as well.  Has anyone tried this? If so please reply with
>your experiences.  Thanks.
>Greg Bajuk
>

 There are two of us in the central valley of califonia that monitor usgs
signals using fftdsp off of vhf radio. I built a vco xr chip to convert my
lehman to tone and feed that into fftdsp as well. At one time I had 3
channels going. 2 usgs and my lehman, all on one screen. It does work. The
only problem is that the fftdsp is not event trigered. You have to record
all the time. The geophone will have to be amplified and filtered before
you can see much from it.


Norman Davis WB6SHI
Shingle Springs, Ca
normd@.............
http://www.directcon.net/normd/index.htm


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: lahr@..................
Subject: Re: 16 bit Audio A/D cards
Date: Fri, 7 Aug 1998 09:56:16 -0600 (MDT)

Norman,

Where did the fftdsp software come from?  Are you using a dsp board
in your PC?

Thanks,
JCLahr

> From psn-l-return@.............. Fri Aug  7 08:18 MDT 1998
> From: Norman Davis WB6SHI 
> Subject: Re: VCO into sound card
> 
> >> For input to a PC sound card, we have considered the possibility 
> >> of using a VCO (voltage controlled oscillator) IC after the 
> >> seismometer pre-amp to convert the seismic signal into an FM audio 
> >> tone whose frequency change is proportional to the input voltage. 
> >> We use this FM-VCO method in all the analogue telemetry that we do, 
> 
> We are already doing this... I run my lehman into an xr chip and then into
> the sound card and view it on fftdsp software. Also remote sites of usgs
> can be heared on vhf radio and mixed into the soundcard and viewed at the
> same time.
> 
> Date: Fri, 07 Aug 1998 07:15:21
> 
> >Since most computer audio cards can convert music/voice/sound input to a
> >digital .wave file, can these cards be used to record and display
> >seismograph files as well.  Has anyone tried this? If so please reply with
> >your experiences.  Thanks.
> >Greg Bajuk
> >
> 
>  There are two of us in the central valley of califonia that monitor usgs
> signals using fftdsp off of vhf radio. I built a vco xr chip to convert my
> lehman to tone and feed that into fftdsp as well. At one time I had 3
> channels going. 2 usgs and my lehman, all on one screen. It does work. The
> only problem is that the fftdsp is not event trigered. You have to record
> all the time. The geophone will have to be amplified and filtered before
> you can see much from it.
> 
> Norman Davis WB6SHI
> Shingle Springs, Ca
> normd@.............
> http://www.directcon.net/normd/index.htm
> 


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: "Ron Horton" 
Subject: New Amateur
Date: Fri, 7 Aug 1998 12:09:48 -0000

Hi to all and thanks for a great site. I am attempting to build a =
version of the Lehman sensor. For the mechanically challenged such as =
myself this means lots of questions. Hope no one gets hurt falling off =
their chair while laughing at my questions. Question #1: How critical is =
boom length ? (ie do I HAVE to cut the 36" rod down to 30") Question #2: =
How can I accurately (inexpensively) determine latitude/longitude of my =
site ?  Will newer versions of Delorme's Street Atlas or similar =
programs give me accurate results ? Thanks for any help in advance. My =
personal e-mail address is ron.horton@........










Hi to all and thanks for a great =
site. I am=20
attempting to build a version of the Lehman sensor. For the mechanically =

challenged such as myself this means lots of questions. Hope no one gets =
hurt=20
falling off their chair while laughing at my questions. Question #1: How =

critical is boom length ? (ie do I HAVE to cut the 36" rod down to=20
30") Question #2: How can I accurately (inexpensively) determine=20
latitude/longitude of my site ?  Will newer versions of Delorme's =
Street=20
Atlas or similar programs give me accurate results ? Thanks for any help =
in=20
advance. My personal e-mail address is ron.horton@........


 


From: "James M Hannon" 
Subject: Re: New Amateur
Date: Fri, 7 Aug 1998 12:52:19 -0500






"Ron Horton"  on 08/07/98 07:09:48 AM

Please respond to PSN-L Mailing List 

To:   psn-l@.............
cc:    (bcc: James M Hannon/CedarRapids/Collins/Rockwell)
Subject:  New Amateur




Hi to all and thanks for a great site. I am attempting to build a version
of the Lehman sensor. For the mechanically challenged such as myself this
means lots of questions. Hope no one gets hurt falling off their chair
while laughing at my questions. Question #1: How critical is boom length ?
(ie do I HAVE to cut the 36" rod down to 30") Question #2: How can I
accurately (inexpensively) determine latitude/longitude of my site ?  Will
newer versions of Delorme's Street Atlas or similar programs give me
accurate results ? Thanks for any help in advance. My personal e-mail
address is ron.horton@........





_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: "James M Hannon" 
Subject: Re: New Amateur OOPS
Date: Fri, 7 Aug 1998 13:06:28 -0500

Oops,
For some reason my text did not get sent with my reply.

Hi Ron,
In answer to your questions.
You do not have to have the boom exactly 30" long 36" would work just fine.
I recently purchased a Delorme topo atlas of my state (Iowa) for about $10.
It has "GPS grids" in other words lat and lon lines.  The maps are so
detailed that they even show my driveway which is about 700 ft long. You
should be able to interpolate the grids to a fiarly accurate lat and lon.

Jim Hannon



_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: "Ron Horton" 
Subject: Thanks
Date: Fri, 7 Aug 1998 15:05:52 -0000

Thanks for reply, Jim. Appreciate info. Have a great day !
Ron










Thanks for reply, Jim. Appreciate =
info. Have a=20
great day !


Ron


 


From: Norman Davis WB6SHI 
Subject: Re: 16 bit Audio A/D cards
Date: Fri, 07 Aug 1998 15:19:22

At 09:56 AM 8/7/98 -0600, you wrote:
>Norman,
>
>Where did the fftdsp software come from?  Are you using a dsp board
>in your PC?
>
>Thanks,
>JCLahr

 Check my web site. there is a link to the site where fftdsp can be had. I
am usning a awe sound blaster but any sound card that is soundblaster
compatable should work. I have it working on 3 different cards.


Norman Davis WB6SHI
Shingle Springs, Ca
normd@.............
http://www.directcon.net/normd/index.htm


_____________________________________________________________________

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From: "Ron Horton" 
Subject: Lehman Plans
Date: Fri, 7 Aug 1998 18:28:31 -0000

Hi Robert,

Thanks for reply. I am using plans from PSN site. Plummers version. Am =
going to try modification to John Cole's idea of using ball bearing. I =
still need to find a base, but otherwise have all the parts. Once I =
succeed in building mechanical portion I'll order Larry's boards and try =
my luck. Probably first week in September. I live in Houston, Texas. =
Yes, the gc stands for "gulf coast". Thanks again. Have a great day.

Ron










Hi Robert,


 


Thanks for reply. I am using plans from PSN site. =
Plummers=20
version. Am going to try modification to John Cole's idea of using ball =
bearing.=20
I still need to find a base, but otherwise have all the parts. Once I =
succeed in=20
building mechanical portion I'll order Larry's boards and try my luck. =
Probably=20
first week in September. I live in Houston, Texas. Yes, the gc stands =
for=20
"gulf coast". Thanks again. Have a great day.


 


Ron


 


From: robert barns <75612.2635@..............>
Subject: Re: New Amateur
Date: Fri, 7 Aug 1998 20:52:55 -0400

Ron,
  I hope you don't have too much trouble getting your Lehman working--I
have found this hobby a source of great satisfaction.
  Certainly, the boom length is not critical--30" is as good as 36". =

However, you might consider that a 30" boom (or even less) will make
building an insulating enclosure easier.  Such an enclosure (dog house?) =
is
absolutely essential since a Lehman is extremely sensitive to air current=
s.
 Be sure to put a small (10W) heater in the top of the box to stagnate th=
e
air.  I built my box out of 2" thick styrafoam (avail. at a lumber yard)
glued together with Elmer's glue.  It seems to work very well.
  I have Street Atlas USA (a great device).  I made a large number of
measurements of my lat and lon with a GPS reciever and the avgerage of
these differs from the Street Atlas lat and lon by only 0.6 arc secs.  Th=
is
is perfect agreement considering the various uncertainties.  This accurac=
y
is far greater than you need for a seismograph.
  Your effort will surely pay off if for no other reason than the joy of
using Larry's WinQuake program.
Bob Barns

The early bird gets the worm but the second mouse gets the cheese.

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From: S-T Morrissey 
Subject: Lehman design ideas
Date: Fri, 7 Aug 1998 20:49:08 -0500 (CDT)

Ron,

Some thoughts on your building the Lehman seismometer:

(I have edited together some previously posted information)

The Lehman is a "poor-boys'" version of the Columbia-Sprengnether
S5000 long-period, of which there are over 1000 in use.
I have scanned a pictorial drawing of it to my web site on
the psn info page. 

http://www.eas.slu.edu/People/STMorrissey/index.html

Of particular interest is the lower suspension of the boom.
Here the boom passes over the frame member attached to the base,
and pulls on the frame via a taught wire arrangement. For
the Lehman, I would make a right angle fixture at the end of
the boom, and have it drop down behind the place where the
bolt and pivot currently are, and pull from the "backside"
with a short ( about 1 cm ) length of music wire.  The operating
principal of this horizontal configuration assumes that forces
about the boom pivot are minimal, and the period is actually
controlled by the angle of the boom with respect to the horizontal.

Some formulae of interest for the horizontal pendulum:
(assuming that the restoring force by the hinges and/or 
pivot are minimal):

The natural period: Tn = 2*pi*sqrt(l/(g*sine i))
 
where l is the boom length in cm, g=980cm/sec^2, i is the angle
that the boom makes wrt the horizontal, measured in radians,
(where sine i = i). For example, a 40 cm boom hanging vertically
as a simple pendulum ( an angle of 90 degrees) has a period of 
1.3 seconds. (a one second clock pendulum is 24.8 cm). When tilted
horizontally to about 4 degrees, the period is 5 seconds. At
about a 1 degree angle, it is 10 seconds, and at about 0.23 deg.
it is 20 seconds. So the period is changing with inverse of the
square root of the angle, which is why long periods are so unstable.
But unstable also means sensitive to smaller ground motions.

So the stability question for a horizontal seismometer depends 
mostly on the mechanical period and the working range of the 
velocity coil; ie how far it can drift before touching. The 
old S5000s that I operate at 15 seconds in vaults rarely 
need to be recentered.  (the working range is +,- 5mm for 
these horizontals). Years ago we ran them at 30 seconds, 
and had to center them about every other month.  I understand 
that most Lehmans operate at 10 seconds give or take, 
but that some can be workable at 20 seconds with more 
frequent adjustment. Of course, the stability of the pier
becomes a major concern. Also, thermal effects on the base
and frame of the instrument can cause major drifting.

My specific hope for someone making a new Lehman would be to 
to make it as rugged and massive as possible so that longer
periods are easily attainable, (which provides a significantly more 
interesting response to teleseisms), but without the problem 
of needing frequent recentering. A 20 second instrument would be nice,
but would need 4 times the tilt stability of a 10 second sensor.
I don't have any information on the actual sensitivity of the 
Lehman designs that are in use. But for comparison to the S5000s 
I am operating at 15 seconds, which have a 32 tpi (turns per inch) 
leveling screw, about 1/100th turn (the leveling knob happens 
to have about a 100 mm circumference) is about 16 microradians, 
and moves the mass about 1mm.  One can calculate how much the 
mass should move when tilted at a given period.

Another useful calculation is the tilt sensitivity of the horizontal
pendulum (which can be used to calibrate the displacement detector)

			z = (g * Tn^2 / 4 * pi^2) * phi

where z is the horizontal displacement of the mass, Tn is the 
natural period, and phi is the tilt of the base at right angles
to the boom, again measured in radians.

From my example above about the S5100: the base is 500 mm, so
the tilt from 1/100 turn of the screw ( which is 0.008 mm) is 
0.008/500 = 0.000016 radian. If Tn = 15 seconds, the mass will
move 0.88 mm, which is close to my approximation.

Evaluating this on my STM-8 horizontal, with l = 40 cm, and 
Tn = 10 seconds, 1/12 turn of the 28 tpi leveling screw is
0.9mm/12 = 0.075mm; the base width is 130mm, so the tilt is
0.075/130 = 0.00058 radians. This calculates to an offset
of the mass of 1.43 cm, which is about what I measure. At
20 seconds, the offset is about 4 times, or 5.7 cm. 

Two points are clear: the stability is inversely proportional
to the square of the period, or conversely, the sensitivity
increases with square of the period.  And the amount of the mass
is not a consideration for the period or the displacement
sensitivity.  As long as it is significantly greater (like 10x)
than the weight of the boom, it will work.

And a final thought: I would forgo the hydraulic damping and
simply use resistive damping with the main coil by shunting
it with an appropriate resistor, which is what is done in
modern seismology. The value of the resistor  can be readily 
calculated; the voltage loss of the resistive damping is easily
made up for with additional gain of the preamplifier.

regards,
Sean-Thomas

_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: bob ogburn 
Subject: Re: New Amateur
Date: Fri, 07 Aug 1998 20:40:26 -0700

Hi Ron,

to locate your station try visiting http://tiger.census.gov/
if you can correlate your station location to the map, the page will
return a high precision
latitude/longitude result.  I checked the grid coordinates obtained from
this page with a GPS receiver - good result.

bob ogburn
PSN Daly City

Ron Horton wrote:

>  Hi to all and thanks for a great site. I am attempting to build a
> version of the Lehman sensor. For the mechanically challenged such as
> myself this means lots of questions. Hope no one gets hurt falling off
> their chair while laughing at my questions. Question #1: How critical
> is boom length ? (ie do I HAVE to cut the 36" rod down to 30")
> Question #2: How can I accurately (inexpensively) determine
> latitude/longitude of my site ?  Will newer versions of Delorme's
> Street Atlas or similar programs give me accurate results ? Thanks for
> any help in advance. My personal e-mail address is
> ron.horton@........




_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: "Phil Giannini" 
Subject: Earthquake lists
Date: 7 Aug 1998 20:58:26 -0800

  REGARDING           Earthquake lists

Hi Arie,
    Thanks for the help, that was indeed the place.  Nice sleuthing. I have
changed the address and bookmarked it again.    Regards, Phil


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: "Ron Horton" 
Subject: Thanks
Date: Sat, 8 Aug 1998 00:48:25 -0000

Thanks to Jim Hannon, Robert Avakian, Robert Barnes, Bob Ogburn, Frank =
Cooper, and others for information and encouragement. I have a lot to =
learn and all help is appreciated. Thanks to Larry Cochrane for =
EVERYTHING. I have already enjoyed reading much of the PSN archives, =
using Winquake (with events from many others), and getting up courage to =
try to build my own "seismograph."

Thanks, Ron Horton









Thanks to Jim Hannon, Robert =
Avakian, Robert=20
Barnes, Bob Ogburn, Frank Cooper, and others for information and =
encouragement.=20
I have a lot to learn and all help is appreciated. Thanks to Larry =
Cochrane for=20
EVERYTHING. I have already enjoyed reading much of the PSN archives, =
using=20
Winquake (with events from many others), and getting up courage to try =
to build=20
my own "seismograph."


 


Thanks, Ron =
Horton


From: "Walt Williams" 
Subject: PSN-L: Lehman Plans & Base Plates
Date: Sat, 8 Aug 1998 07:37:24 +0000

Hello Ron,

Regarding the base: After much wasted time and with help from the 
nice people of the PSN-L --use thick aluminum or something similar. 
My current base is 5/16 inch thick aluminum and that is not thick 
enough. The 'word' on the street is 1/2" to 1" thick.  Thicker the 
better.

Good luck.

Walt Williams, 98.08.08
dfheli@..............

p.s.

See my 'modified' plummer's Lehman at:
http://www.pacificnet.net/~dfheli/seismo.html

You can click on highlighted text next to thumbnails for larger 
image.
=================================================== 

------- Forwarded Message Follows -------
From:          "Ron Horton" 
To:            "PSN-L" 
Subject:       Lehman Plans
Date:          Fri, 7 Aug 1998 18:28:31 -0000
Reply-to:      PSN-L Mailing List 

Hi Robert,

Thanks for reply. I am using plans from PSN site. Plummers version. Am
going to try modification to John Cole's idea of using ball bearing. I
still need to find a base, but otherwise have all the parts. Once I
succeed in building mechanical portion I'll order Larry's boards and
try my luck. Probably first week in September. I live in Houston,
Texas. Yes, the gc stands for "gulf coast". Thanks again. Have a great
day.

Ron



_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: 
Subject: MASS FOR LEHMAN SEIS
Date: Sat, 8 Aug 1998 16:57:38 EDT

TO:  PSN FRIENDS
For those of you building a Lehman Seis. of planning to build one or wanting
to upgrade an existing one, I just returned from a shopping trip to Pasadena,
California (U.S.A.).  While there I bought a soild brass mass for a future
Lehman that I am building.  The mass is a cylinder 3 inches tall by 4 inches
in diameter with two tapped holes on one of the 4inch sides for 5/16 inch
bolts.  The cylinder weighs 11.5 lbs.  The cost for this cylinder was $25.00.
There are three left in the store and they are not shown in the stores
Catalog.  If you are interested the name of the store is:
	C and H Sales Company.  2176 E. Colorado Blvd., Pasadena, Calif. 91107
	Mailing address:  P.O. Box 5356, Pasadena, Calif. 91117
	email address:  c&h@...........
	Telephone # :  Toll Free (800) 325-9465
You may order by telephone and they will ship anywhere.  This surplus company
has been in business since 1948.
Jim Allen
Cerritos, California

_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: Edward Cranswick 
Subject: PSN/School presentations at AGU
Date: Sat, 08 Aug 1998 17:08:50 -0600

Ted & Jan-
    Below is a description of a special session at the December AGU meeting in San
Francisco that would be a perfect opportunity for a PSN/school computer-poster
presented by the students of Almaden School.  I will be out of the office for the
next week, but please let me know what you think.
-Edward

S12   Digital Communications in Seismology: Glimpses of the 21st Century Seen Today?
The explosive growth in digital communications brought on by widespread public
interest in the internet has profoundly changed seismic instrumentation. Digital
communication links to seismic stations for real-time data collection, near-real-time
data collection, or for least
state of health data are becoming standard experimental procedure. The rapid
evolution of this technology, however, has led to a proliferation of different
approaches to solving the same problem. The primary goal of this session is to
provide a forum for comparison of the different technologies currently available. Our
hope is that this will help move the community toward a set of standards that will
allow for a more transparent exchange of data between networks and for distribution
to the broader community. In addition, widespread availability of digital
communication links to sensors and between sensor networks promises to profoundly
change the scientific infrastructure of seismology. Papers are also solicited on
ideas for scientific problems that could be addressed by a network of networks of
seismic instruments on a national to global scale with thousands of broadband seismic
stations.

Conveners: Gary L. Pavlis, Department of Gelogical Sciences, Indiana University, 1005
10 Street, Bloomington, IN 47405, Phone: +1-812-855-5141, Fax: +1-812-855-7899,
E-mail: pavlis@............ and Steve Malone, Geophysics Program, University of
Washington, Box 351650, Seattle, WA 98195, Phone: +1-206-685-3811, Fax:
+1-206-543-0489, E-mail: steve@......................

Ted Blank wrote:

> I will speak to my son's science teacher.  When I mentioned it to her
> last year she was very excited about the idea.  Thanks for proposing to
> sponsor us.
>
> Ted Blank
> San Jose, California
>
> On Thu, 23 Jul 1998, Edward Cranswick wrote:
>
> >
> >
> > --
> > 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".
> >
> >
>
>   ------------------------------------------------------------------------
>
> Subject: Re: Santa Cruz Seismic Instruction Software
> Date: Thu, 23 Jul 1998 16:47:09 -0600
> From: Edward Cranswick 
> Organization: US Geological Survey, Golden, CO
> To: Jan Froom 
> CC: cranswick@...............
> References: <5030300023233283000002L032*@MHS>
>
> Jan-
>         I thought that you, Steve, and Ted might do something, and I think that
> I forwarded some kind of info to the PSN-L.  However, I was not really
> connected with it myself, and I wasn't going to try to tell you guys
> what you should do (what maybe I should have helped to do myself).  In
> any case, the IRIS meeting does not get as much coverage as the AGU
> meetin in San Francisco in December which Larry and Ted attended last
> year with me.  So I think it would be a great idea to pursue the idea
> that you and Ted talked about last year of having a bunch of students
> submit a poster for the AGU meeting 6-10 December this year
> . You guys can write the
> abstract and prepare the poster and I, as an AGU member, can sponsor it
> and get the USGS to pay for it. The abstract deadline for that is:
>
>         August 26, 1998         (Postal/express mail submissions)
>
>         September 2, 1998       (Interactive Web Form submissions)
>
>         Because we only have about a month, please let me know ASAP what you
> think and also CC a copy to me at  which what
> I am trying to make my address for PSN-related activities.
> -Edward
>
> Jan Froom wrote:
> >
> > It's a shame that we couldn't have gone to this conference, since I think
> > Steve, Ted & I  are about the only ones in this area that are actually working
> > with schools.... well Elementary, Middle & High.  I tried, and got a note from
> > a lady in Arizona that forwarded my request to a lady in Santa Cruz....  but
> > after that I got no answer.
> > ---------------------- Forwarded by Jan Froom/San Jose/IBM on 07-22-98 11:26 AM
> > ---------------------------
> >
> > Ted Blank
> > 07-21-98 01:13 PM
> > To: Jan Froom/San Jose/IBM@IBMUS
> > cc:
> > From: Ted Blank/Santa Teresa/IBM @ IBMUS
> > Subject: Re: Santa Cruz Seismic Instruction Software
> >
> > I tried to get the information from Larry but it was all very vague.  Finally
> > he called me the night before to say it was the next day but by that time I had
> > other plans.  Oh well.
> >
> > Regards, Ted
> > DB2 Performance, IBM Santa Teresa Lab, San Jose, California
> >
> > Ted Blank/Santa Teresa/IBM .....(from Notes)
> > IBMUSM50(TED) .............................(from PROFS/VM)
> > ted@.......... ..............................(from internet sites)
> > STLVM6(BLANK) .............................(for LIST3820 files etc.)
> > Tie: 8-543-3589    Ext:  (408) 463-3589   Fax:  (xxx-2614)
>
> --
> 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".



--
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: PSN and schools
Date: Sat, 08 Aug 1998 17:22:09 -0600

John-
    I heartily recommend that you submit an AGU abstract about "Quake
Trackers" to the special session: "S12   Digital Communications in
Seismology: Glimpses of the 21st Century Seen Today?"  I looked fast
through the QT website and was impressed by what you and Dave and others
are doing.  I will be out of the office for the next week, but I will
scrutinize what you all are doing more carefully when I return.  See you
in San Francisco!
-Edward

John Taber wrote:

> Edward,
>
> You wrote:
>
> >Having a bona fide school connection has always been one of the Holy
> >Grails of the PSN.
>
> Perhaps we can help with that connection.  We have started a school
> seismic network here in New Zealand, and you can visit the beginnings
> of our Quake Trackers home page at
> http://www.geo.vuw.ac.nz/seismology/Quake_Trackers/.
>
> We are getting off the ground with the considerable help of Larry
> Cochrane and Dave Nelson and others including local teachers
> and students, and with initial funding from the NZ
> Earthquake Commission (the national earthquake insurance company for
> NZ).  We are using Larry's A/D board and software and
> the 4.5 Hz geophones that Dave has shown are effective at picking
> up NZ seismicity.  Following Dave's lead in the South Island
> (at Alan Munro's Southland Boys High School)
> we have installed a seismograph at the first of
> the 5-6 schools we plan to have set up in the Wellington region
> by the end of the year.   The plan is to add at least 5-6 schools per
> year.
>
> We are mirroring PEPP's curriculum pages with
> slight modifications to make them more applicable to NZ.  We
> are also working with Larry and local teachers to develop activities
> based around WinQuake.
>
> Any comments and suggestions for the web site are most welcome.
>
> We will be storing the data on our web site since the data
> will be primarily for local events, but it will be stored in
> PSN format so all WinQuake users will be able to access it.
> The database should be up before the end of the month.
>
> I've followed your efforts ever since I was shown your first PSN AGU
> abstract, and have wanted to get involved in some way but never seemed
> to have sufficient time and/or funding.  Now through global
> cooperation it all seems to be comming together.
>
> Do you know if there is going to be a session on seismology
> education in schools at AGU this year, and do you think it would be
> worthwhile for us to submit an abstract?  I wasn't initially
> planning to come this year (it's a long way from NZ) but if you
> think there would be sufficient interest, I think I could
> arrange it.
>
> Regards,
>
> John
>
> John Taber              School of Earth Sciences, Victoria University
> John.Taber@.........    P.O. Box, 600, Wellington, New Zealand
>
> phone: +64-4-472-1000
> fax:   +64-4-495-5186
>
> _____________________________________________________________________
>
> 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: PSN and CNSS (Re: Use this list -- PSN Station list)
Date: Sat, 08 Aug 1998 18:02:23 -0600

PSN, Steve Hammond, Steve Malone-
    I think it would be useful if the PSN were represented in the list of global
seismograph stations that is being compiled by CNSS, i.e., see below:

>       Also, on a different subject, since I know you are interested and
>involved in the Peoples Seismograph Network I have a question.  I have
>been tasked with doing an inventory of seismic networks in the US and am
>getting a response from most of the regional networks (ie members of the
>CNSS).  The `PSN' has never been an actual part of the CNSS since it is a
>pretty ad hoc group with no central authority (as it should).  However,
>for this inventory (and maybe just to increase its visability it might be
>nice to include stations form the PSN in what I am doing.  You may find a
>descritpion of what I need on the WEB at:
>       http://www.cnss.org/NETS/request.survey.txt
>
>Any ideas you might have on how I could do this, please let me know.
>
>
>       Steve Malone                    E-mail: steve@......................
>       Geophysics Program              Phone: (206) 685-3811
>       University of Washington        FAX: (206)543-0489
>       Box 351650                      Office: ATG-226
>       Seattle, WA 98195       http://www.geophys.washington.edu

One of the requested pieces of information is a the name of a contact person to
represent the seismograph network.  After some discussion about this, John Lahr
(USGS) and I decided that it would not be appropriate for either of us to be this
contact person. If we want to keep the PSN for the "Public", any "semi-official" PSN
positions should not be occupied by professional seismologists. John and I can serve
as liasons between the PSN and the USGS, but I don't think a public group should be
represented by a professional.  Steve Hammond, Jerry & Dorothy Darby, Charlie Rond,
Larry Cochrane and Dave Nelson -- to name a few -- have done wonderful jobs of
taking it upon themselves to do alot of PSN work, and I think that is the best way.
If this sounds like I am shrugging off responsibility, you are right -- I am. If PSN
members do not want do something, it is not my job to tell them that they should. I
really don't know what should be done; I just sometimes have some ideas which I
sometimes voice, like what I am saying now.
    I will be out of the office for the next week.
-Edward

Steve Hammond wrote:

> See may last few notes today. Yes, you need to add Jan Froom, Dick
> Chelberg, and Bruce Kinney. I have the notes I made when adding them to
> the list. I must have not saved the work...
> Regards, S--
>
> Edward Cranswick wrote:
> >
> > Steve-
> >     Good to talk to you last Saturday.  I got kind of bogged down on the
> > Part#A for CNSS (Steve Malone).  Attached is a list of PSN participants I took
> > from your list and alphabetized, and which I was going to use, following your
> > suggestion, for item#2 (STAFF).  However, I notice several people are absent,
> > such as Dick Chelberg and Bob Ogburn (whom you noted) who I remember did alot
> > to establish PSN. I want your advice about where to go with the 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".
> >
> >     ---------------------------------------------------------------
> > Al Allworth
> > Almaden Country Middle School
> > Robert (Bob) L. Barns
> > Jeff Batten
> > Ted Blank
> > Martin S. Brewer
> > George Bush
> > Fred Bruenjes
> > Steve Clark
> > Larry Cochrane
> > Darrell Collins
> > Claudio Conti
> > Frank Cooper
> > Karl Cunningham
> > Dorothy & Jerry Darby
> > Paolo Frediani
> > Tom Frey
> > Kim & Jan Froom
> > Sam Gazdik
> > Phil Giannini
> > Grayling School, Alaska
> > Roger Griggs
> > Lucas Haag
> > Mark Halliday
> > Bob Hammond
> > Steve Hammond
> > Jean-Jacques Hunsinger
> > Albert Judge
> > Meredith Lamb
> > Robert L. Laney
> > Dennis Leatart
> > Bob Lewis
> > Barry Lotz
> > Jim Lovell
> > Gregory A. Lyzenga
> > Douglas McConnell
> > McGrath School, Alaska
> > Stephen Mortensen
> > Francesco Nucera
> > Ken Navarre
> > Dave Nelson
> > Pearl Creek School, Alaska
> > Tony Potenzo
> > Roberto E. Pozzo
> > Charlie Rond
> > Liberio Rossi
> > Giovanni Rotta
> > Pete Rowe
> > Jack Sandgathe
> > Bill Scolnik
> > Donald Sieber
> > Malcolm Sinclair
> > Roger Sorensen
> > South Valley Jr. High
> > Southland Boys High School
> > SRA, Fairbanks, Alaska
> > Peter Styles
> > Bob Teller
> > Charlie Thompson
> > Sam Toon
> > Kees Verbeek
> > Arie Verveer
> > Dick Webb
> > Ron Westfall
> > Clark Wockner
> > David Wolny
> > Brian Zimmerman



--
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: Norman Davis WB6SHI 
Subject: Di-150rs support for emon
Date: Sun, 09 Aug 1998 18:51:56

 Has anyone heared if Ted has got the drivers working for the DI-150rs
modual?  He said he was working on it but never heared if he finished it up.






Norman Davis WB6SHI
Shingle Springs, Ca
normd@.............
http://www.directcon.net/normd/index.htm


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From: Peter 
Subject: Re: Di-150rs support for emon
Date: Sun, 09 Aug 1998 22:33:55 -0700

Norman,

Did Ted ever get a di150 to work on?
I sure could use e mon as I now record round the  clock

Pete

Norman Davis WB6SHI wrote:

>  Has anyone heared if Ted has got the drivers working for the DI-150rs
> modual?  He said he was working on it but never heared if he finished it up.
>
> Norman Davis WB6SHI
> Shingle Springs, Ca
> normd@.............
> http://www.directcon.net/normd/index.htm
>
> _____________________________________________________________________
>
> 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: Di-150rs support for emon
Date: Mon, 10 Aug 1998 07:19:23

At 10:33 PM 8/9/98 -0700, you wrote:
>Norman,
>
>Did Ted ever get a di150 to work on?
>I sure could use e mon as I now record round the  clock
>
>Pete
>

 How do you find the quakes in your recorded files??

Norman Davis WB6SHI
Shingle Springs, Ca
normd@.............
http://www.directcon.net/normd/index.htm


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From: Fred and Tina 
Subject: Re: Di-150rs support for emon
Date: Mon, 10 Aug 1998 07:51:30 -0700

Pete,  Are you sure eMON will work on the DI150 ?.  I thought it
had a very specific output string.  Whats wrong with the software that
shipped with it. I couldnt get the VB routines to work either (off the
web page)

Fred

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Public Seismic Network Mailing List (PSN-L)


From: ralvarez@........ (Raul Alvarez)
Subject: psn and the general public
Date: Mon, 10 Aug 1998 17:20:31 -0600 (MDT)

Hi all,

Have a question for the group.  Has there ever been any discussion
on having, say, PSN shirts, etc?   It seem it would be a good way to promote
our cause.

Raul
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                                                       
         "My dreams are the seeds of my reality,    
            nurtured in the womb of my soul"        
                  RJA, 1985                            
                                                         
                   Raul J. Alvarez
              La Estrellita Observatory
                  Bellvue, Colorado
              e-mail ralvarez@........ 
           homepage  www.frii.com/~ralvarez
            "The Renaissance Experimenter"
                  doing research in:
    Radio and Optical Astronomy, Seismology, Weather,
       Computers, Instrumentation and Neat Stuff!
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


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Public Seismic Network Mailing List (PSN-L)


From: Pinpoint 
Subject: Re: psn and the general public
Date: Mon, 10 Aug 1998 17:20:00 -0700

At 05:20 PM 8/10/98 -0600, Raul Alvarez wrote:
>Hi all,
>
>Have a question for the group.  Has there ever been any discussion
>on having, say, PSN shirts, etc?   It seem it would be a good way to promote
>our cause.

? I'll buy one but I didn't really understand the cause? Where can one be
purchased? Common Larry get an artistic person going on this one for
sure..I like it! Seriously!
Bob


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: Pinpoint 
Subject: Re: psn and the general public
Date: Mon, 10 Aug 1998 17:20:00 -0700

At 05:20 PM 8/10/98 -0600, Raul Alvarez wrote:
>Hi all,
>
>Have a question for the group.  Has there ever been any discussion
>on having, say, PSN shirts, etc?   It seem it would be a good way to promote
>our cause.

? I'll buy one but I didn't really understand the cause? Where can one be
purchased? Common Larry get an artistic person going on this one for
sure..I like it! Seriously!
Bob


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: S-T Morrissey 
Subject: Re: VBB temperature comp
Date: Mon, 10 Aug 1998 20:07:46 -0500 (CDT)

Barry,

Maybe your bimetallic element is too stiff. The one I use has a
bimetallic coil about 1/8" wide and 3/4" dia when coiled, About
5 turns of the coil are left when I straighten out the 3" lever arm.
I measured the force it applies to the boom with small weights on
threads, and it is about 3.5 grams at the present setting. This
does not appear to affect the free period or the response in a 
significant way; the step calibration is the same.
I haven't attempted fine adjustment of it yet; I just ran another
multi-pair signal cable from the recorder to downstairs where the
pier is so I can record the temperature and mass postion (and the
micro-barometer also).

I have tried your suggestion of having the bimetallic element move a 
mass with temp change. The strip I have does not move perceptibly
with a 1 degree C change, but this 1 deg C has required about a 
1 cm shift of the 10 gram trim mass on the boom to compensate it. 
It is too wimpy to support a significant trim mass. But using the 
thin bimetallic spring directly is much more sensitive; like I 
said, you can test it by shinning a penlight on it.

The old WWNSS LP vertical seismometers (the Sprengnether S5000) DO
have a very large bimetallic compensator. It is about 4cm wide and
an inverted U about 10 cm high, with an attached mass of about
200 grams (the seis mass is 11kg). It is also quite stiff.

You mention that your VBB output varies several volts on a daily
basis. This is typical of VBB sensors; even without thermal and
barometric noise, they sense earth tides. Usually they are connected
to a 24 bit digitizer (1:16 000 000), and the offset is removed
in later processing. With our 12 and 16 bit ADCs, the VBB needs
a single pole high pass amp to remove the large DC signal. I use
1 megohm into 1 000 microfarad (= 1000 seconds; use 2 ea. 2000 uf
low leakage capacitors in series connected + to +) with a gain of 2 
for the "line" output of the seismometer. The data and calibrations
I have shown are via this arrangement.

Regards,
Sean-Thomas

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From: "Francesco" 
Subject: NEW RELEASE OF I.E.S.N  WEB SITE
Date: Tue, 11 Aug 1998 04:05:01 +0200

HELLO GUYS,
NOW IT'S ON LINE THE NEW VERSION OF OUR WEB SITE.
GOOD NAVIGATION !

I.E.S.N. - PSN ITALY
Francesco Nucera



English version at:   http://space.tin.it/scienza/frnucer/English.htm









HELLO GUYS,


NOW IT'S ON LINE THE NEW VERSION OF =
OUR WEB=20
SITE.


GOOD NAVIGATION !


 


I.E.S.N. - PSN ITALY


Francesco Nucera


 


 


 


English version at:   http://space.tin=
..it/scienza/frnucer/English.htm


From: Fred and Tina 
Subject: Re: 16 bit Audio A/D cards
Date: Mon, 10 Aug 1998 19:09:55 -0700

Norman,  Are you using three at once in the same system ?  If so some
setup info would be appreciated.

Fred

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Public Seismic Network Mailing List (PSN-L)


From: "Charles R. Patton" 
Subject: Re: New Amateur-coordinate location
Date: Mon, 10 Aug 1998 21:23:32 -0700

If your location shows up on the MSN terraserver:
 http://terraserver.microsoft.com/
 you can do a very fine location. It's free and it gives you a great
aerial view of your location.  (Just a hint on something it took me a
while to notice -- When you have zoomed down and it starts returning
aerial photographs, notice that you can click on the upper left portion
of the photograph window where it says "Map".  Then you get a standard
road map like presentation.  This makes life a lot easier in finding out
where you are. Home in where you want to go, then click the same spot
again and it will return to the photo mode.)  The problem is who to
believe -- the terraserver data or the quad maps from the USGS.  In my
case figuring from quad maps vs the terraserver I had a difference of
0.0207 degrees latitude and 0.0244 degrees longitude. Perhaps they are
using different datum points?  Maybe somebody can tell us.  Anyway,  the
quad puts me NW of the location figured from the terraserver.  You can
easily resolve 50 ft. or less using the terraserver -- so if the base
coordinates are right, you will get a very accurate location.

Charles R. Patton
charles.r.patton@........


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From: Arie Verveer 
Subject: LP filter design program
Date: Tue, 11 Aug 1998 08:05:17 +0800

Hi, I was just downloading some info from the Burr-Brown site
and came across a low pass filter design program:
Its worth downloading from:

   http://www.burr-brown.com:80/Applications/Applications.html

   program is called      FilterPro
   Application notes     AB-034



Arie.


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Public Seismic Network Mailing List (PSN-L)


From: Roger Sorensen 
Subject: Re: psn and the general public (T-shirts & Caps)
Date: Tue, 11 Aug 1998 08:59:58 -0700

> At 05:20 PM 8/10/98 -0600, Raul Alvarez wrote:
> >Hi all,
> >
> >Have a question for the group.  Has there ever been any discussion
> >on having, say, PSN shirts, etc?   It seem it would be a good way to promote
> >our cause.

------------------------------------------------------------------

I too thought that it would be fun to have
PSN T-shirts. 

About two years ago I came to an agreement
with the leaders of the group to use their
copyrighted logo. My original though was 
to hand-make them one at a time. While
working out the details on the logo use, there
seemed to be a fair amount of interest, so
I did the artwork and had a batch silk-screened
by a professional shop here in town. 

As it turns out, there was little interest.
I would be happy to sell the remainder of the
first and only batch at a price that just
covers the T-shirt and screen costs. I 
also have mesh baseball caps with the PSN
logo on them. You get the same price deal 
on them too.

T-shirts:
Black Hanes Beefy T's with a medium blue PSN logo
   # in stock   Size   Price
    6           Large   $12.00
   16           X-Large $12.00

Black Mesh Ball Cap with medium blue PSN logo
 22 in stock -  Price 6.00


Prices include postage to U.S.A (Foreign
orders, e-mail me with your address and
I'll see what I can do)

California residents include local sales tax.

Payment: Visa, MC, Money Order, Cashiers Check,
         Personal Check (allow 10 days for personal
         checks to clear. 

If you have any questions, feel free to e-mail me.

Roger Sorensen (a PSN station)
Caliber Graphics
21110 Celtic St.
Chatsworth, CA U.S.A. 91311 (34.27N 118.59W)
(818) 709-5117 (9 am - 6 pm Pacific Time)

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From: Greg 
Subject: Re: psn and the general public (T-shirts & Caps)
Date: Tue, 11 Aug 1998 09:23:02 -0700

> About two years ago I came to an agreement
> with the leaders of the group to use their
> copyrighted logo. My original though was

I have little or no interest in the shirts or hats, but what does the
PSN logo look like?

,Greg

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From: Roger Sorensen 
Subject: PSN (C) logo - psn.jpg 9.64K
Date: Tue, 11 Aug 1998 11:32:01 -0700

Greg wrote:

> I have little or no interest in the shirts or hats, but what does the
> PSN logo look like?
> 
> ,Greg

Here is the PSN logo. It is copyrighted and shall only be used with
permission of the PSN.

My apologies if the size of this message has caused a problem.

From: "James M Hannon" 
Subject: Re: PSN (C) logo
Date: Tue, 11 Aug 1998 16:09:38 -0500

Ok For the next question. How does one go about getting permission to use
the PSN logo?  It would be nice to make up a couple of different size .gif
files and use them on a web site for identity recognition or link buttons
and such.

Jim Hannon



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From: watson@................ (Charles Watson)
Subject: [Fwd: BULLETIN: SOHO on the road to recovery]
Date: Tue, 11 Aug 1998 14:29:30 -0700

FYI

-- 
---/----
Charles P. Watson
Seismo-Watch

From: S-T Morrissey 
Subject: bimetallic compensator mounting
Date: Tue, 11 Aug 1998 22:27:01 -0500 (CDT)

Barry,
Re: installation of bimetallic thermal compensator:

I guess that my description of the installation is not clear.
If you refer to the latest mechanical of drawing of the sensor
that shows the side profile, there is a "Boom support" post
between the spring and the feedback magnet. Near the top,
the arrow points to a 1/4" hole which is occupied by a 3" SS
bolt. This is used to clamp the boom by looping a rubber band 
over the boom and both ends of the bolt. THis is also the
contact point for the free end of the bimetallic strip.

THe coil of the bimetallic element is mounted by its center
at the second hole in the boom toward the spring, about under
the end of the word "adjust". The coil spirals clockwise, then
straightens out, and the free end is placed UNDER the 1/4" bolt
on the support post. Once the coil is mounted, its center is turned
about 1/2 turn counterclockwise for a preliminary setting that applies
about 3 to 4 grams of force to the bolt. Since the coil contracts 
when warmed, this moves the free end down, applying less force on  
the bolt, allowing the boom to rise, correcting for the main 
spring effect.

The bimetallic element is from a 5" Taylor thermometer. The 
contact with the bolt could be replaced with a loop of nylon
thread to eliminate any stiction noise.

Regards,
Sean-Thomas



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From: S-T Morrissey 
Subject: Lead weight source
Date: Tue, 11 Aug 1998 22:39:01 -0500 (CDT)

Re: lead mass for seis

A handy lead mass for Lehman and other sensors is the 5-pound
weight used for diving weight belts. It is about 3" square by
1" thick, with two slots for the belt. It can be cut with a
hacksaw (for smaller masses) or drilled. It is available at
diving shops; I purchased several at the "Sports Authority" 
for about $5 each. For a vertical sensor, lead is essential,
since the atmospheric buoyancy is inversely proportional to
the mass density. Depleted Uranium would be even better!
For horizontal sensors, other metals are OK, but bulkier.

Regards,
Sean-Thomas


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From: barry lotz 
Subject: Re: bimetallic compensator mounting
Date: Tue, 11 Aug 1998 20:23:17 -0700

Sean Thomas
   You know how when you are trying too hard to think of something it
doesn't come to mind? Well at work it finally dawned on me what you were
saying. I appreciate the time to describe where you put the coil. I
installed a "Morrissey fishing pole" tonight. I took the free end of the
bimetal coil and attached a strip of 0.001" shim stock with a small
brass nut on the end. I set the nut in the boom channel behind the
feedback coil. Since I don't have exactly the same bolt arrangement I
made a brass pedestal and mounted the center of the bimetal coil to the
top of it. The coil center is fixed and the coil free end is moving. I
likewise took up some of the weight of the nut with a turn of the coil
center. Anxious to see what happens when the temperature stabilizes.
Another reason I used a
pedestal and nut on the end of the coil is that if I want to move it
towards the boom hinge later on for a possible different sensitivity it
won't be as hard for me to move and reattach
it.                                            Regards
                                              Barry

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From: Larry Cochrane 
Subject: Event in N. Cal
Date: Wed, 12 Aug 1998 07:28:03 -0700

Hi Everyone,

We just had an moderate event here in Northern California. This one I
definitely felt and was recorded on my strong motion sensors. Event my
ADX05 picked it up! The first event for this sensor. The news just said it
was a 5.4 near Hollister. There where two small foreshocks then the big
one. More later...

-Larry Cochrane
Redwood City, PSN
  

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From: meredith lamb 
Subject: 5.4Ml Central California
Date: Wed, 12 Aug 1998 10:05:00 -0600

Can't raise NEIC at the moment, but with the 5.4Ml msg by
Larry, the
http://www.avo.alaska.edu sites says:

98/08/12 14:10:25 Lat 36.75N Long 121.46w, Depth 8.9
Mag 5.4Ml  Central California

Meredith Lamb




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From: "Giovanni Rotta" 
Subject: NEW SEISMIC STATION WEB PAGES OF RESIA (Udine) ITALY
Date: Wed, 12 Aug 1998 18:58:10 +0200

Hi friends !!
I am very happy to present to you the web pages of my experimental seismic
station now present in Resianet web site 

http://www.geocities.com/~resianet (with english version)

So, I also offer to you the opportunity to visit my splendid valley !
(be quite... there is also the english version !)

Have my best regards,
Giovanni

Giovanni Rotta
rottag@..........
Via F. Pizzigoni, 10
33010 Resia (Udine) Italy
Lat. 46.373N   Long. 13.305E
QTH Locator JN66PI

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From: "Steve Carniglia" 
Subject: Re: Di-150rs support for emon
Date: Wed, 12 Aug 1998 10:17:02 -0700

Hi...I am the one who sent Ted the DI-190....
Last time I talked to him, he was still working on it with some hope of
being able to make it work...

Steve



-----Original Message-----
From: Norman Davis WB6SHI 
To: psn-l@............. 
Date: Sunday, August 09, 1998 7:06 PM
Subject: Di-150rs support for emon


> Has anyone heared if Ted has got the drivers working for the DI-150rs
>modual?  He said he was working on it but never heared if he finished it
up.
>
>
>
>
>
>
>Norman Davis WB6SHI
>Shingle Springs, Ca
>normd@.............
>http://www.directcon.net/normd/index.htm
>
>
>_____________________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email listserver@............. with the body of the
>message: leave PSN-L


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From: "Francesco" 
Subject: R: NEW SEISMIC STATION WEB PAGES OF RESIA (Udine) ITALY
Date: Wed, 12 Aug 1998 19:46:32 +0200

Ma chi credi che ci venga in quella valle di =
desolazione.................padana......

AHAHAHAHA

CHE FAI COPI LA PRESENTAZIONE I.E.S.N. ???????

Bye
Fran









Ma chi credi che ci venga in quella =
valle di=20
desolazione.................padana......


 


AHAHAHAHA


 


CHE FAI COPI LA PRESENTAZIONE =
I.E.S.N.=20
???????


 


Bye


Fran


From: Norman Davis WB6SHI 
Subject: Re: Di-150rs support for emon
Date: Fri, 14 Aug 1998 06:45:03

At 10:17 AM 8/12/98 -0700, you wrote:
>Hi...I am the one who sent Ted the DI-190....
>Last time I talked to him, he was still working on it with some hope of
>being able to make it work...
>

 I was wondering if ted knows about the suff on the dataq page. There is
quite a bit of stuff on the data stream and pinouts and the likes. Also
some visual basic source code for a program called alarm. Sounds like it
might be useful to him..

http://www.dataq.com


Norm


Norman Davis WB6SHI
Shingle Springs, Ca
normd@.............
http://www.directcon.net/normd/index.htm


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From: Fred and Tina 
Subject: Note to Windaq/DI150 users
Date: Fri, 14 Aug 1998 07:56:29 -0700

For anyone using the DI150 for datalogging. Pete(Alarm@............
showed me a usefull tip.  If your system goes down while recording, 
You can run Scandisk(Win 95) to recover the otherwise unusable file.

Normally you will get a "Illeagal file header 44" error. 

Anyone know of any low cost, high capacity UPS's.

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From: "Steve Carniglia" 
Subject: Re: Di-150rs support for emon
Date: Fri, 14 Aug 1998 09:06:54 -0700

Hmmmmmmmm......maybe but last time I talked to Ted, the problem was a
graphic problem between the DI190 and EMON....he is able to talk to the
device with no problem....He also has all the software that was supplied
with the DI190 and the full docs.

73
Steve


-----Original Message-----
From: Norman Davis WB6SHI 
To: PSN-L Mailing List 
Date: Friday, August 14, 1998 7:24 AM
Subject: Re: Di-150rs support for emon


>At 10:17 AM 8/12/98 -0700, you wrote:
>>Hi...I am the one who sent Ted the DI-190....
>>Last time I talked to him, he was still working on it with some hope of
>>being able to make it work...
>>
>
> I was wondering if ted knows about the suff on the dataq page. There is
>quite a bit of stuff on the data stream and pinouts and the likes. Also
>some visual basic source code for a program called alarm. Sounds like it
>might be useful to him..
>
>http://www.dataq.com
>
>
>Norm
>
>
>Norman Davis WB6SHI
>Shingle Springs, Ca
>normd@.............
>http://www.directcon.net/normd/index.htm
>
>
>_____________________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email listserver@............. with the body of the
>message: leave PSN-L


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From: Karl Cunningham 
Subject: Re: Note to Windaq/DI150 users
Date: Fri, 14 Aug 1998 11:48:45 -0700

At 07:56 AM 8/14/98 -0700, you wrote:
>Anyone know of any low cost, high capacity UPS's.

Fred --

I have found 600-800 watt UPS's at electronic-oriented swap meets in So.
Calif. for the $20 range.  They often need new batteries, but you can
usually plug them in to see if they at least work.


Karl Cunningham
La Mesa, CA.
PSN station #40
karlc@.......

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From: Fred and Tina 
Subject: Re: Note to Windaq/DI150 users
Date: Fri, 14 Aug 1998 16:20:14 -0700

Thanks Karl,  Actually i'm more in need of duration types. The power
outage last week lasted 4hr's.  What about replacing the exsisting
internal batt's with a couple car batteries or maybe a deep cycle type. 

Anybody forsee any problems with this aside from one batt discharging
into the other if the cells short. Could fuse it or use a PTC
overcurrent fuse.  Any thoughts

Fred

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From: S-T Morrissey 
Subject: UPS systems
Date: Fri, 14 Aug 1998 19:26:38 -0500 (CDT)

We operate several of them here at the seismic observatory and at
the major remote sites. With the 1 killowatt "Best" brand units, 
we parallel the internal battery (ies) with external batteries, 
using low voltage, low resistance  "rectifier" fuses for protection. 
The large DC battery connectors are helpful (Grainger 6A070 series,
about $10). It is VERY important that all the batteries that are
connected in parallel be of exactly the same type and age, even 
if this means replacing the original internal battery with a new 
one, or simply omitting it. We use the 90 amp-hr Delco photo-
voltaic batteries, or else the deep-discharge "marine" type 
batteries. With continuous float charging, they only last 3 to 
4 years.

We have also made some hybrid UPS systems using commercial 1kw precision
inverters (by TOPAZ), large 3-phase DC supplies (13.6V at 250 amps), and
large "stationary" batteries by Exide. These are 660 amp/hr cells
with high calcium plates, which are used in stationary service like
telephone exchanges and backup power for mine hoists. They are 
guaranteed for 20 years. With 660 Ah cells, we get about 6 hours
of UPS power at the 1kw level. (We can get the generator going by then).
(Also, we limit our loads to about 750 watts).

Our loads operate continuously from the inverters, so the AC-DC 
supply has to provide its input (like 100 Amps) plus re-charge the
batteries in a resonable time. It is also precise enough to be set
within 10 millivolts to properly float the batteries. So with the 
batteries always connected to the inverter, there is no power 
transfer needed when the AC goes out. However, we do have a 
"failsafe" arrangement that connects the external loads to the 
AC line in the rare event that the inverter fails. We also have
a pair of digital timers that force an "equalizing" charge voltage
for several hours once a month by switching on a different resistor
in the AC-DC supply voltage feedback reference. These large 
systems weigh about 1 500 lbs.

Regards,
Sean-Thomas

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From: Greg 
Subject: Re: Note to Windaq/DI150 users (UPS)
Date: Fri, 14 Aug 1998 21:08:51 -0700

Fred and Tina wrote:
> 
> Thanks Karl,  Actually i'm more in need of duration types. The power
> outage last week lasted 4hr's.  What about replacing the exsisting
> internal batt's with a couple car batteries or maybe a deep cycle type.

I doubt anyone's warranty will cover that, but if you want to spend a
reasonable amount on a commercial UPS... I used to work at a place with
some really nice APC Smart UPS 2200 VA running 486s with all kinds of
electronics attached. One time we had a power outage and after like 2
hours there was no (less than 1% that the display would show) drop in
the battery capacity. 

I have a little APC Back UPS 450 at home and aside from the annoying
beep every time the power dips, I like it plenty. The next time I buy
one I'll get another APC, but probably a Back UPS Pro or a Smart UPS. I
have never lost anything due to power problems with the UPS on my
computer. Of course, I don't need 4 hour uptimes though ;) I paid about
$180 in 1995? Still the same battery it came with.

APC and I'm sure other UPS manu's have web sites.

http://www.apcc.com/

You can also call APC and get a recommendation. If you're an engineer
you can add another 20% ;)

The best part about buying a commercial UPS is that your computer is
protected by their warranty that if lightning gets through they'll cover
you to a point. The only thing is that you have to have everything
plugged into the UPS.

I don't work for APC so this is not a shameless plug. 

,Greg

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From: Karl Cunningham 
Subject: Re: Note to Windaq/DI150 users
Date: Sat, 15 Aug 1998 00:46:13 -0700

At 04:20 PM 8/14/98 -0700, you wrote:
>Thanks Karl,  Actually i'm more in need of duration types. The power
>outage last week lasted 4hr's.  What about replacing the exsisting
>internal batt's with a couple car batteries or maybe a deep cycle type. 

Fred --

My 486 that runs SDR draws about 40 watts with the video monitor off, and
the electronics on my seismo another 11 watts.  So, an 800 watt UPS loaded
to 50 watts will take an outage for a while.  I haven't ever measured it,
but I think it would be several hours with the internal gell cells.  Of
course, the bigger the battery you use the longer it will go.

Karl Cunningham
La Mesa, CA.
PSN Station #40
karlc@.......

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From: "Francesco" 
Subject: CENTRAL ITALY  MB 4.8
Date: Sat, 15 Aug 1998 10:59:26 +0200

05.18
MB 4.8
LOC.: CENTRAL ITALY  (Rieti=20


I.E.S.N.  PSN-ITALY









05.18


MB 4.8


LOC.: CENTRAL ITALY  (Rieti =



 


 


I.E.S.N. =20
PSN-ITALY


From: Larry Cochrane 
Subject: Strong motion data recorded on my ADXL05 sensor.
Date: Sat, 15 Aug 1998 22:15:49 -0700

Hi Everyone,

I just completed a new web page documenting the strong motion data I got
from the 5.4Ml Hollister California event the other day. This page compares
the ADXL05 monolithic accelerometer chip sensor and a commercial
Kinemetrics three component FBA-23A strong motion sensor I am monitoring.

The URL is: http://psn.quake.net/StrongMotion.html

What I got was about +-6.1mg of acceleration from the event. This event was
about 108km (67 miles) from me and was large enough to be felt, but not
large enough, at that distance, to move anything around in the house.

Regards,
Larry Cochrane
Redwood City, PSN
 

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From: meredith lamb 
Subject: New Italian web sites
Date: Sun, 16 Aug 1998 00:51:36 -0600

Hi guys,

The two Italian web sites both look great.  The I.E.S.N site is
really extensive and impressive with the number of instruments
which seems to have grown in number.

Giovanni Rotta's web site is also very worthwhile visiting and it
gets my vote for being the most beautiful web page in the
seismographic community.

Thanks and well done guys.

Meredith Lamb


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From: frankcnd@.......... (Frank Condon)
Subject: Balleny Event Revisited
Date: Sun, 16 Aug 1998 02:55:41 -0700 (PDT)

Hello All:
I was wondering how close was the Balleny Seismic Event to the Magnetic 
South Pole?

Frank Condon
"Located in the seismic corridor somewhere between Fontana & Mammoth Lakes"


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From: barry lotz 
Subject: Event? 
Date: Sun, 16 Aug 1998 08:31:33 -0700

Well It was Mt San Gorgonio Ca @ 13:34:40 UTC
   34.12N, 116.93W   M=4.8
                 Barry

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From: Roger Sorensen 
Subject: Re: Strong motion data recorded on my ADXL05 sensor.
Date: Sun, 16 Aug 1998 10:55:27 -0700

Good work on the ADXL05 page, Larry.

What sensor components did you end up with? I used the parts described
in the Application Notes from Analog, and found the noise floor to
be excessive - somewhere in the range of 5% of a G. It would take a
large jolt to get a full P/S reading from the sensor. ( a 5M, 7 miles
away didn't even do it)

I'd be interested to hear more about your design.

Roger 
Chatsworth, CA (34:16:15N 118:35:37W)

Larry Cochrane wrote:
> 
> Hi Everyone,
> 
> I just completed a new web page documenting the strong motion data I got
> from the 5.4Ml Hollister California event the other day.

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From: Mark Wilson 
Subject: RE: Re: Strong motion data recorded on my ADXL05 sensor.
Date: Sun, 16 Aug 1998 16:12 -0400

Well, I knew that I should have put paper on my PS1 last night.

I live about 3 mi from the epicenter of the San Gorgonio quake that happened this morning.
Mild shake, nothing major, about 15-20 seconds..  I am still picking up aftershocks, in the 2 range on my Lehman and the Ps1.

I always know if the epi is close.  Low altitude planes always fly over shortly after.

Ciao, nice weekend..

Mark Wilson
mark@..............
http://www.markwilson.com
Where the San Andreas and the San Jacinto meet..	;)


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From: John Hernlund 
Subject: Re: Strong motion data recorded on my ADXL05 sensor.
Date: Sun, 16 Aug 1998 17:29:31 -0700 (MST)

Hey Larry,
   Do you have both sensors situated on the same pier or location?  How do the
FFTs compare?

******************************************************************************

			       John Hernlund
     		          E-mail: hernlund@.......
      WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/
		    http://www.public.asu.edu/~hernlund/

"Enlightenment is man's emergence from his self-imposed immaturity.
Immaturity is the inability to use one's understanding without guidance from
another.  This immaturity is self-imposed when its cause lies not in lack of
understanding, but in lack of resolve and courage to use it without guidance
from another.  Sapere Aude!  "Have courage to use your own understanding!"-
that is the motto of enlightenment.
-Immanuel Kant: "An Answer to the Question: What is Enlightenment?"

******************************************************************************


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From: Edward Cranswick 
Subject: Re: Strong motion data recorded on my ADXL05 sensor.
Date: Sun, 16 Aug 1998 18:55:40 -0600

Larry-
    Very interesting comparsion.  I note that there is a very strong resonance
which can be seen in the monochromatic nature of the FBA23 timeseries. The
corresponding FFT reveals a set of resonance peaks at about 1.4, 3.7, 6.5 Hz.
This looks something like the 1-3-5 progression of the fundamental resonance
and its first and second harmonics that is characteristic of seismic waves
reverberating in a low-velocity layer over a high-velocity halfspace.  However,
the observed peaks do not exactly the 1-3-5 ratio. Nonetheless, assuming that
the 1.4 Hz peak is the fundamental quarter-wavelength resonance of the near
surface, and assuming an S-wave velocity of 200 m/s for the low-velocity
near-surface sediments that underlie your house, and using the formula for the
quarter-wavelength resonance:

                    f  =  v  / (4 * h)

where "f" is the fundamental quarter-wavelength frequency (Hz), "v" is the
seismic velocity of the low-velocity layer (m/s) , and "h" is the thickness of
that layer (m), we get:

                    h = v / (4 * f)  = 200 / (4 * 1.4) = ~ 36 m

This value seems reasonable with uncertainties of a factor of two (20 - 70 m)
given the uncertainties of the seismic velocity low-velocity material (100 -
400 m/s).  When in doubt, flap your arms, that's what I say.  More later.
-Edward

Larry Cochrane wrote:

> Hi Everyone,
>
> I just completed a new web page documenting the strong motion data I got
> from the 5.4Ml Hollister California event the other day. This page compares
> the ADXL05 monolithic accelerometer chip sensor and a commercial
> Kinemetrics three component FBA-23A strong motion sensor I am monitoring.
>
> The URL is: http://psn.quake.net/StrongMotion.html
>
> What I got was about +-6.1mg of acceleration from the event. This event was
> about 108km (67 miles) from me and was large enough to be felt, but not
> large enough, at that distance, to move anything around in the house.
>
> Regards,
> 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".




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From: Larry Cochrane 
Subject: Re: Strong motion data recorded on my ADXL05 sensor.
Date: Sun, 16 Aug 1998 23:19:39 -0700

At 05:29 PM 8/16/98 -0700, John Hernlund wrote:
>Hey Larry,
>   Do you have both sensors situated on the same pier or location?  How do
the
>FFTs compare?

The two sensors are separated by about 18 inches. Both sensors are screwed
to the wood floor in my spare bedroom. This floor is sitting on the
concrete slab of the house. The concrete slap sits on the ground, no
basement or crawl space.  

-Larry Cochrane
Redwood City, PSN  

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From: Larry Cochrane 
Subject: Re: Strong motion data recorded on my ADXL05 sensor.
Date: Mon, 17 Aug 1998 21:49:11 -0700

At 10:55 AM 8/16/98 -0700, Roger Sorensen wrote:
>Good work on the ADXL05 page, Larry.
>
>What sensor components did you end up with? I used the parts described
>in the Application Notes from Analog, and found the noise floor to
>be excessive - somewhere in the range of 5% of a G. It would take a
>large jolt to get a full P/S reading from the sensor. ( a 5M, 7 miles
>away didn't even do it)
>
>I'd be interested to hear more about your design.

The sensor uses two ADXL05 chips in a "push-pull" configuration. The output
from both chips are summed together and then amplified and low pass
filtered. The signal then goes to my A/D card. I used the "push-pull"
configuration because it seems to work pretty well on the SG sensor. With
the SG sensor the two receiver plates, one producing a positive voltage and
the other a negative, are also summed together etc... Since my sensor has a
little less internal noise, around 3mg, it seems to help a little.

-Larry Cochrane
Redwood City, PSN




  

 

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From: meredith lamb 
Subject: [Fwd: Seismicity analysis tools]
Date: Tue, 18 Aug 1998 10:56:44 -0600

Heres a reference to a free program from the British Geological
Survey.



From: John Hernlund 
Subject: Event on 8/4/98
Date: Tue, 18 Aug 1998 14:31:15 -0700 (MST)

Hello All,
   I was out of town for fives weeks and returned to discover a very nice
quake record recorded on 8/4/98 here in Tempe, Arizona.  It occurred somewhere
around 17:00 UTC on 8/4/98, but I could not find any listing for this event on
the USGS sites.  Does anyone have any info???

******************************************************************************

			       John Hernlund
     		          E-mail: hernlund@.......
      WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/
		    http://www.public.asu.edu/~hernlund/

"It is easier to excuse an ignorant person who claims that theory is
unnecessary and dispensable in his supposed practice, than to excuse a
Sophist who concedes its value to the schools (as, perhaps, only a mental
exercise) but who at the same time maintains that matters are quite
different in practice- that as one leaves school to enter the world, one
will realize one has been pursuing empty ideals and philosophical dreams-
and, in a word, that what sounds good in theory is of no practical
use."
-Immanuel Kant, On the Proverb: That May be True in Theory, But Is of No
Practical Use

******************************************************************************


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From: lahr@..................
Subject: Re: Event on 8/4/98
Date: Tue, 18 Aug 1998 16:39:20 -0600 (MDT)

John,

Here are the QED events for August 4th:

98/08/04 00:48:35   8.40N  82.66W  33.0 4.9Mb A  PANAMA-COSTA RICA BORDER REG
98/08/04 02:13:38  61.83N 150.94W  67.0 4.5Mb A  SOUTHERN ALASKA
98/08/04 05:07:38  21.28S 179.61W 615.5 4.7Mb B  FIJI ISLANDS REGION
98/08/04 06:23:15  16.23S 179.06W 600.0 4.3Mb C  FIJI ISLANDS REGION
98/08/04 11:42:01  37.80N  57.23E  33.0 5.1Mb B  TURKMENISTAN-IRAN BORDER REG
98/08/04 11:46:49  52.94S  21.67E  10.0 5.0Mb B  SOUTH OF AFRICA
98/08/04 12:18:18  41.26N 137.91E 262.5 4.4Mb B  EASTERN SEA OF JAPAN
98/08/04 12:28:35  52.92S  21.86E  10.0 5.3Mb B  SOUTH OF AFRICA
98/08/04 13:03:16  52.92S  21.87E  10.0 4.5Mb    SOUTH OF AFRICA
98/08/04 15:51:01  56.72S 147.00E  10.0 5.5Ms B  WEST OF MACQUARIE ISLAND
98/08/04 17:35:04   0.43S  80.03W  33.0 5.2Mb A  NEAR COAST OF ECUADOR
98/08/04 17:48:20  52.93S  21.61E  10.0 5.4Ms C  SOUTH OF AFRICA
98/08/04 18:59:19   0.47S  80.05W  33.0 7.1Ms A  NEAR COAST OF ECUADOR
98/08/04 22:55:32   0.53S  79.65W  33.0 4.1Mb C  ECUADOR

JCLahr



_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: watson@................ (Charles Watson)
Subject: [Fwd: ALERT: Major X-Class Solar Flare Alert #3 - 18 August]
Date: Tue, 18 Aug 1998 17:18:46 -0700

Here we go again.

-- 
---/----
Charlie

From: Steve Hammond 
Subject: CNSS Inventory of Seismic Networks
Date: Wed, 19 Aug 1998 13:16:20 -0700

I intend to submit this to Steve Malone within the next 48 hours. Please
review it and provide comments or corrections ASAP. Also take a look at
http://www.cnss.org/NEWNETS/ to get an idea of how the information is to
be used.  

----------Submission information -----------


Name:

Public Seismic Network


Staff:

WWW Staff:
Larry Cochrane, Redwood City California http://psn.quake.net
Bob Hammond, Fairbanks, Alaska  http://www2.polarnet.com/~whammond
Charlie Rond, Memphis, Tennessee
http://gandlf.ceri.memphis.edu/~rond/psn
Dave Nelson, Dunedin, New Zealand http://psn.quake.net/dave/quakes.htm
Jerry&Dorothy Darby, Pasadena, California
http://www.pacificnet.net/~darby/index.html
Steve Hammond, (principal author) San Jose California
http://pw2.netcom.com/~shammon1/psnsj.htm
Arie Verveer, Kalamunda Western Australia http://www.iinet.com.au/~ajbv/
Francesco Nucera, Italy http://space.tin.it/scienza/frnucer
Tony Potenzo, Kailua-Kona, Hawaii
http://www.geocities.com/CapeCanaveral/Hangar/7195/ 

Station site staff:
Al Allworth \AA1, Almaden Country School School \ ACS, Albert Judge
\AJ1, Avie Verveer \AV1, Bob Hammond \BH1&2, Barry Lotz \BL1, Bill
Scolnik \BS1&2, Bob Teller \BT1, Bruce Kinney \BK1, Bob Ogburn \OB1,
Charlie Thompson \BUE, Brian Zimmerman \BZ1&2, Claudio Conti \CC1&2,
Clark Wockner \CW1, Darrell Collins \DC1&2, Malcolm Sinclair \DHQ,
Dennis Leatart \DL1, Douglas McConnell \DM1, Dave Nelson \DN1-4, Donald
Sieber \DS1, Fred Bruenjes \FB1&2, Frank Cooper \FC1, Bob Lewis \FD1&2,
Francesco Nucera \FN1-3, Steve Hammond \FX1&2 FS1-3, David Wolny \GJC,
Gregory A. Lyzenga \GL1, Giovanni Rotta \GR1, Grayling School, Alaska
\GRY, South Valley Jr. High \GS1, HSC High School; Fairbanks, Alaska
\HSC, Jeff Batten  ( Caltech Seismo Lab. Pasadena, Ca.) \JB1-3,
Jean-Jacques Hunsinger \JCH, Jerry&Dorothy Darby \JD1, Jim Lovell \JL1,
Jack Sandgathe \JS1, Karl Cunningham \KC1-3, Jan Froom \GC1&2, Kim Froom
\KF1, Ken Navarre \KN1, Kees Verbeek \KV1, Larry Cochrane \LC1-3, Lucas
Haag \LH1, Tom Frey \LK1, Liberio Rossi \LR1, Martin S. Brewer \MB1,
McGrath School, Alaska \MCG, Mark Halliday \MH1&2, Meredith Lamb \ML1-3,
Malcolm Sinclair \MS1, Sam Gazdick \OK1, Pearl Creek School, Alaska
\PCK, Paolo Frediani \PF1&2, Pete Rowe \PR1, Richard Chellberg \RC1,
Robert L. Barns \RB1, Roger Griggs \RG1, Robert L. Laney \RL1, Charlie
Rond \RM1, Roberto E. Pozzo \RP1&2, Roberto E. Roger Sorensen \RS2, Dick
Webb \RW1, Ron Westfall \RW1, Steve Clark \SC1, Phil Giannini \SFX&SFZ,
Sam Gazdik \SG1, Southland Boys High School \SHS, Stephen Mortensen
\SM1, SRA High School, Fairbanks, Alaska \SRA, Peter Styles, Sam Toon
\ST1, Ted Blank \TB1, Tony Potenzo \TP1&2, George Bush \TSR

Geographic Location:

There are 73 member operated PSN sites around the world with
approximately 2/3 of the stations sites inside the continental US,
Alaska, Bermuda, and Hawaii. The remaining world-wide sites include in
country networks and recording sites in New Zealand, Australia, Italy,
England, and Western Europe. A detailed site map including station
information is available on the WWW at:
http://psn.quake.net/dave/people.htm


Network Code:

PSN


Institution:

The Public Seismic Network is an all volunteer organization with two
bylaws which are to never have elected officials or conduct formal
meetings more than 4 times in any calendar year. The PSN normally has
one public meeting a year and communicates regularly on the WWW using a
mailing list-serv which can be found at http://psn.quake.net. Central
contacts and key spokes persons for the group are any of the members
listed as WWW Staff or Ed Cranswick who regularly acts as a public
relations and spokes person for the group.

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


Stations:

43 short period, 51 broadband, and 2 drum recording systems. 


Receding:

The recording equipment and method used is at the members choice.
Typically the data digitization rate is 30-60 sps and recorded locally
on a PC with a dynamic range of 72-96db (12-16 bit resolution). Both
triggered (EMON software) and continues receding (SDR software) methods
are used. 

Seismic Data Recording (SDR) software is offered by Larry Cochrane and
is used in conjunction with special hardware also offered by Larry that
collects data from 1 to 4 channels at 50, 25, 10 or 5 samples per
second(SPS). All data is saved to disk so you can replay the data and
produce PSN format files that Winquake can view. The data is stored in a
file for each channel with the file extension of CHANx.jjj wherex = 1 to
4 and jjj = Julian day or 001 to 365. Each day, starting at midnight
local time, a new record file will be created. Old record files will be
purged from your system depending on a setting under the F6 settings.
You must make sure you have enough disk space available for the number
of channels you have, and, the number of days of data you want to save.
Each channel will produce about 6 megabytes per day at 50 SPS.

The Earth Monitor (EMON) program is freely distributed by Ted Blank and
designed to run continuously in the PC. It periodically checks the input
from the seismometer and amplifier for earthquake-like activity. An
earthquake data file is saved to disk only when an earthquake signal is
detected. An options file called EMON.OPT is read at startup. You can
change the parameters that control saving data by changing entries in
the OPT file. You can collect data from up to three seismometers
simultaneously. A separate quake file will be written for each device.
Figure 1 shows a sample of how the EMON screen appears when it is
monitoring for earthquakes. Notice that three quake files have already
been saved to disk, and their names appear in the space at the bottom of
the screen. If your PC has graphics capability (as this one did), the
box at the upper right displays a real-time trace of the output of the
seismometer. However, EMON can collect data on a PC which does not have
graphics capability. You will just need to use a different PC to display
the data later. EMON creates PSN formatted files that quake View or
Winquake can view.

Data Analysis:

Members use Winquake and QuakeView software locally to analyze waveform
data, determine the distance to the epicenter, and origin times.
Additionally, http://psn.quake.net/cgi-dos/event.exe offers near
real-time WWW access to events recorded in the SF Bay Area by short
period and Broad band instruments.


Data Availability:

Data is shared via a mailing list which can be found at
http://psn.quake.net/ Additionally, the following WWW sites provide
on-line wareform data access:

http://space.tin.it/scienza/frnucer/English1.htm  Italy
http://psn.quake.net/  Redwood City, California
http://psn.quake.net/dave/quakes.htm  New Zealand
http://gandalf.ceri.memphis.edu/~rond/psn/  Memphis, Tenn


Other Products:

Examples of information found on the PSN WWW sites include:
Build your own Seismograph Station, White Paper on A/D system dynamic
range needed for seismic 
recording., Article by Bob Barns on a method you can use to calibrate
your sensor. Article by Allan Coleman on lengthening the natural period
of a Lehman seismometer. Plans are freely available for the Lehman
Sensor, the Shackleford-Gundersen Sensor, a Force-Balance Seismometer by
Karl Cunningham and a Leafspring Broadband Vertical Seismometer by
Sean-Thomas Morrissey. Software including EMON Version 7.0 written by
Ted Blank and Winquake and Seismic Data Recorder (SDR) version 1.8
developed and offered by Larry Cochrane. Items offered for sale include
12/16 bit A/D cards and amplifier systems.


New or Proposed development:

Members continue to build and refine the Leafspring Broadband Vertical
Seismometer by Sean-Thomas Morrissey. This broadband seismograph is
proving to be a very versatile sensor.


Approximate size of data submission for CD-ROM. 

31MB 1991-1997 1,401 objects recorded and uploaded to the original PSN
BBS network, available from http://pw2.netcom.com/~shammon1/psnsj.htm  
5M on-line data access from http://psn.quake.net/cgi-dos/eqfiles.exe
Daily updates on new events as they occur.


Acknowledgements:

The PSN would like to acknowledge the many employees of the USGS that
have spent personal time working with the PSN members and PSN supported
activities by providing continuing support, advice, and council which
has helped to further educate the group and develop it into a world-wide
organization of amateur seismologists.

_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: meredith lamb 
Subject: The Lamb S-G type Seismometer with a linear Hall-Effect sensor
Date: Wed, 19 Aug 1998 20:32:34 -0600

Hi Guys,

Finally have evolved my giant S-G type horizontal seismos, into their
contemplated final version.  Each weighs 37 pounds.  One second natural
period.  The Magnetic eddy current damping uses neodymium magnets and
an aluminum plate.  19" height X 14" base.  The seismo is literally
made out of old large computer main frame drive disks and stainless
steel spacers.  The hinge, boom, and mass are hanging down
through the center holes (3&7/8") of smaller 10.5" (1/8" thick) diameter
disks which are stacked 3 to a tier, with 4 tiers up from the base
"plate". The mass is a round brass inertia wheel out of old data tape
recorders and weighs about 4 lbs each.  The hinge is very light .001"
thick, by 1/4" width common brass shim stock with ~ 3/16" length 
exposure between clamps.  The boom is 1/4" diameter aluminum rod. 
The mass to boom ratio is ~ 15 to 1, with the adjustable clamps taking
up most of the weight.  The seismo is massive but with a strong frame
construction, with low center of weight and is a balanced design
overall. 

The primary goal of building these seismometers has been not for
a personal precise seismometer, but for a more long term useful
evaluation of the linear Hall effect sensor.  Thus far, it appears to
be exceeding our expectations. Obviously my science/electronic skill 
level is low, so the reader can expect many possible inconsistancies,
and they are invited to correct any misinformation presented, or, add
their own information which I would be very interested to hear of. 

The sensor is a Allegro/Sanken A3515LUA, which they call a
ratiometric, linear hall-effect sensor.  It looks like a small 3 wire
plastic transistor.   It actually has a number of stages therein,
including a chopper, and a high gain op-amp.  See:

http://www.allegromicro.com/control/prodline.htm

The web site covers alot of details and spec's.  There is also
many, many web sites with hall-effect as the subject.  Apparently 
there is many manufacturers of linear Hall devices, but Allegro seems
to be the major one with such an extensive line and general specialty.   

The circuit amplifier currently in use was designed by Robert
Lamb, and is still evolving, from its Feb-March 1998 first version.
Currently it is using one IC, a  National Semiconductor LF412A,
which is a dual fet op-amp.  Eventually the circuit/s will somehow
be made public.  Its really a AC (alternating current/velocity) or
a DC (direct current/displacement) switchable circuit.  The AC
circuit use has been used with my horizontal S5000, and the only
quake record from that setup is archived on PSN as 980804a.ml4.
That at the time used an Allegro A3503 hall sensor; which is about
4 times less sensitive than the present A3515 Hall sensor, but seems
to be better for wider mass drift seismos, and still stay in scale.
The recent central California 5.4 quake is a DC low gain ~100
(corrected from 25), record of  980812a.ml4, which is from the S-G
previous version N-S instrument.  The high tilt rate was due to a
influx of water from a heavy downpour in the crawlspace. Future ml4
quake records will be from the S-G and AC output usually.   The gain I
use on AC is ~ 500, which with the amplifier in the hall, is probably
more like 1500-2000 in reality.  Eventually more circuits will be
built other than the one in use by Robert, and the one he built for
my use.  Robert has used his circuit since about March on his Lehman
like seismometer, but there is no recording there. 

A brief written description of the present circuit is this:  The Hall
has small voltage regulators, both + and -, which in a adjustable 
resistive bridge configuration, deliver a signal to the first stage,
which is DC with feedback.  The first stage uses a output selected
capacitor for the frequency of interest, and is fed to the 2nd stage
(AC) and is selectable for gain.  With a switch, one can select DC
or AC outputs. The DC stage is most useful for zeroing the hall.  Two
capacitors really determine what is shown on the output.  The first 
is really a filter capacitor from the input to ground.  The 2nd is 
the primary one, and can be changed to the instrument used.  I use a
10 microfarad mylar capacitor, and it seems to work well for the normal
phases of more intense interest; i.e., p-s etc.  In this circuit 10
microfarad are equivalent to 10 seconds, but the hall signal
still will show attenuated longer period phases, with its constant
signal on the capacitor.  For reference see the 980804ml4; some of the
Lr Lq phases were of about 1 minute duration on closeup. 
 
The Hall sensor on the S-G seems to be almost a natural companion, with
its almost null mass drift.  Previous versions didn't seem to need much
attention after 2-3 days of settling in.  The Hall sensor is mounted on
the bottom of the boom pointing down.  The neo magnets are mounted on
edge upright, with a simple aluminum spacer inbetween.  The neos
themselves rest on a round steel plate and held down by the attraction.
Using a sliding movement, zeroing by physical magnet movement and the
base plate screw is attained.

The Hall sensor has what is called a quiesant voltage, which is usually
midway between the + and - bipolar power supply voltages.  This is read
with the sensor magnet removed and denoted.  Upon reinstalling the
sensor magnet, I use a DMM, to arrive at the zero position.  Due to
tilt influence, I usually have to adjust, back away, read, and adjust
the zero for it.  I don't usually try to get an exact zero, as a
difference of only afew tens of millivolts is more than sufficient.
My AD card and SDR computer program allow for minor and major offsets
with DC initial zeroing...and any future DC potential.  Being as most
recording is AC mode, their is no zero problem. Its possible to mark
the center of the magnets, but the DMM is much easier to use for
zeroing. The A3515 seems to have a much narrower range of movement than
the A3503; perhaps 1/20".  A adjustment overscale will show either 0.5v 
or 4.97V, but it isn't to difficult to adjust it to around 2.47V; the
quiesant voltage or zero (found per each device).
  
The aluminum plate and magnet damping, although antique in age/useage,
seem to be adequate for the present.  I use an unknown mfger assembly,
which is "U" shape, with one,  two-pole magnet affixed inside the unit
on each side ( two total 2 pole magnets).  They are 2 pole neodymium,
about 5/16" thick X 2.3" Length, X, 1 & 9/16" width.  They are painted
white, and perhaps have a gauss around 14K each.  The aluminium plate is
1/16" and goes between the magnets in the 1/4" gap easily.  Damping
seems to be slightly overdamped.  I have no real idea of the original
use of these assemblys, but, they too are likely computer surplus.

The normal Hall device may use a 2 pole magnet with only 1 face or
occasionally other magnets in various push-pull configurations.  Their
gauss range is generally around 800.  For this seismometer, I use a 4
pole neodymium magnet (bat-butterfly-wing shape) as is.  In the center
of the magnet running up and down the width is a magnetic junction of
the magnets, with seems to be relatively sharp.  The Hall device in
the circuit is directional (N-S), and registers any change as a
corresponding +-. The Hall is a slide by function of this junction
field, and so there is basically no severely limited range limit as
with alot of seismological sensors.  The neodymium magnet I use has a
gauss of ~ 14,000.  The Hall manufacturer states that there is no
maximum gauss per device, but a high gauss field may make the output
non-linear.  Robert Lamb has ran linearity checks with high gauss neo's
and the linearity is very good even with this high a field.
Unfortunately I can not identify the magnet I use as to company.  It
is 1 & 3/4" in length (45mm), 11/16" in width as measured on one end
(17 mm), and 5/32" thick (4 mm).  Mine have been chrome plated
externally, and they are likely older computer surplus material.

By putting a non-magnetic spacer between two 4 pole magnets, and with
the hall in between, the sensitivity generally increases roughly 40%.
Magnetic fields variations in such a constrained "clamp" configuration,
does not seem to show any influence from other exterranious normal
magnetic influences; i.e., passing cars etc.

The total range of mass motion is about 3/4".  The Hall sensors range
of distance motion is alot less and seems to be dependent on the Hall
device used.  I've seen the A3503 show a signal over 1/2" of movement,
and with the present A3515, a range of about 1/20th", can make it
out of range, especially when its between two, 4 pole neo magnets.  

Sensitivity is related to the distance between the magnet and the Hall
device. I generally run it at a distance of some .030-40" from the
magnet face.  The closer it gets the more sensitivity increases.

Balancing the magnet field strength with the Hall for its desired 
range seems to be an experimental determination.  There are limits,
none of which is really understood at the moment.    

The seismometer actually has 2 IC sockets (plug ins), for 2 Hall
devices, however being as the enclosure needs more insulation, it is 
only run on one Hall with AC output.  Perhaps some day, both Halls can
be run, with one on DC and the other on AC...hence a DC/tiltmeter/zero
reference and a AC/velocity unit in one.

The seismometer "tiers" provide adequate space for possible add-ons like
feed back.

I presently use Larry Cochranes 16 bit AD card, SDR, and Winquake
programs.  I've no experience with other resources of computer recording
programs, cards, etc.

With my 3 component Sprengnether velocity set already in operation,
I do make a ready comparison to the same N-S sensors.  The Sprengnethers
with their greater range of motion display somewhat more tilt effects.
The Hall output seems much more accurate of actual ground motion.
Otherwise, the Hall in use, seems to fairly replicate "big brother",
and seem more capable of higher frequencys of interest.  The Hall gets
a signal all the time, whereas the coil/magnet is kind of a pulsating
nature.

Personal opinion wise, I think the linear Hall effect devices are the
choice of simpler, cheaper and very sensitive seismometers.  The Hall
device itself is relatively cheap and available, whereas other sensor 
approaches are scarce availability resources and getting depleted with
time, or their total cost, construction aspects, seem to be unweldy.
I obtained my Hall units from Newark Electronics for $4.32 each plus
shipping, insurance, etc.  See pages 731 & 833 of their 1988 catalog,
(116) which can be requested via the internet at:

http://www.newark.com/

Their are probably other sources around, for the Allegro linear Hall
devices. 

I bought my neo's for $1 each, but most surplus sources are
ranging up ~ $8 each.  Unfortunately surplus sources don't identify
their magnets very well, let alone 2 pole from 4 pole magnets. There
are wing magnets out there that are only 2 pole and even ferrite of
the same general shape.  If you have access to a surplus store with
a selection, bring along a little 2 pole bar magnet and run along the
flat length of the suspected 4 pole; around the middle if it is 4 pole,
it will want to flip, if not, it isn't a 4 pole. Otherwise, the
internet may yield sources.  Two pole magnets can work, if the Hall
is run over the magnetic junction between the N-S; most likely an
edge, but the junction may not be as sharp as those on 4 pole magnets
and the result may not be as encouraging.  Apparently, 4 pole magnets
are not as abundant as I originally thought.  Alot of surplus sources
have the 4 pole units within metal assemblys.  Disassembly varies from
impossible to easy.  Generally the magnets are glued to the metal and
can be wedged or knocked off with little or no harm, but not always.

The circuit and mechanical seismometer descriptions are of the joint 
efforts of Robert Lamb and myself.  Evidently the Hall works, but at
the moment, additional work remains to understand it, and ensure it will
be more stable.

Eventually the 2nd E-W seismo will come on line (ml5), as soon as I
quit klutzing up the connections-ha.

Thanks, Meredith Lamb


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: Karl Cunningham 
Subject: Recorders available
Date: Thu, 20 Aug 1998 10:41:27 -0700

Greetings, All --

I've been cleaning up, and have the following two chart recorders that I
will be happy to send off to good homes for the cost of shipping them.  I
had both working some years ago, but they have been in storage ever since
and I cannot guarantee their operation.

These are two Molytek 2700's, with operation manuals.  They are rack
mounted and use thermal paper about 10" wide (four extra rolls come with
each).  They are digitally controlled, programmed via an attached keyboard,
32 input channels, with programmable sensitivity from 1 millivolt to 10
volts.  They also accept thermocouple inputs for temperature recording.
Chart speed is programmable from 0.01"/hr to 120"/hr.  Now for the bad news
-- the record on the paper is not continuous but a series of dots made by a
heated stylus, and it will only put a dot down about once per second at
best (maybe not even that fast, I don't quite remember).  The stylus
multiplexes between channels, so it's slower yet when doing multiple
channels.  And given the width of the paper, the chart gets pretty busy
when drawing anything but straight lines with more than about 15 channels.
They would be best used for testing very slow things like thermal drifts,
long-term variations, etc., but not very good for continuous seismic
recording.  Shipping weight: about 20kg each.

If anyone is interested, email me directly; please do not send replies to
the list.

Karl Cunningham
La Mesa, CA.
PSN station #40
karlc@.......

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Public Seismic Network Mailing List (PSN-L)


From: meredith lamb 
Subject: "Seismometrists are...sort of...OK"
Date: Thu, 20 Aug 1998 11:57:59 -0600

Hi All,

Title is a delicious humor quote from Robert Lamb-ha.  Anyway,
I got my latest improved version giant S-G type horizontal
running on the 19th.  North-South orientation.  Linear Hall
sensor pickup with AC output.  One second natural period with
a 10 second high pass filter.  Gain of 500 + amplifier in device.
See 98/08/20aml4.  Compare to 98/08/20aml1, which is a
velocity 15 second coil/magnet seismo with the same orientation.

Main improvement assistance credit (boom-mass weight ratio),
goes to Sean-Thomas Morrissey.

Thanks, Meredith Lamb

P.S.,  The S-G has a plastic tall kitchen wastebasket liner
covering it.  Nothing is too good for it.  Have a nice linear Hall
sensor-less day-ha.

Unfortunately I missed out on the Rat Islands, Aleutian 
Islands quake series...power failure.


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: lahr@..................
Subject: Re: Recorder desired
Date: Thu, 20 Aug 1998 14:58:58 -0600 (MDT)


Karl's posting reminded me that I would love to find
a used (read very inexpensive or free) strip-chart
recorder that has ~2.5 inch-wide paper.  At public 
exhibits it's fun to have people create a "seismic"
event and then give them the chart as a record of 
their accomplishment.  The smaller the better, as
table space is usually at a premium.

Cheers,
JCLahr
################################## John C. Lahr
################################# Seismologist
################################ U.S. Geological Survey
############################### Geologic Hazards Team, MS966
############################## PO Box 25046
#############################/##############################
############################/###############################
Denver, Colorado 80225-0046 ################################
    Phone: (303) 273-8596 ##################################
     Fax: (303) 273-8600 ###################################
         lahr@........ #####################################
                http://giseis.alaska.edu/lahr
               http://lahr.org/john-jan


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: S-T Morrissey 
Subject: seis covers: nothing too good.
Date: Thu, 20 Aug 1998 18:58:10 -0500 (CDT)

Meredith,

Rubbermaid could cash in on the market for seismometer covers.
For the pricey STS-1s I start out with a 20-gallon round planter,
cover it with 4" fiberglass matt, nest it in a 30 gallon round tote
tub, which is covered with another 2" of fiberglass then wrapped
with REFLECTIX sheeting taped with duct tape. Similar packaging
is used for the STS-2 and the smaller Guralp, whose shipping crate
is designed to be a thermal cover.

Major drawback: in the cavern, mice made a nest in the outer layer.
Also, round containers only work with compact sensors; the STS-1
baseplates are about 30 cm across, and the vacuum bell jar is
about the same height. (Another reason I want to reduce the size
of the STM sensors.) For larger sensors, like your S5000s, we use
4" rigid poly foam with dovetailed corners and candy-apple sticks
(or kabob skewers) to hold the enclosure together.

Regards,
Sean-Thomas

_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: "d.sevold" 
Subject: Earthquake Hysteria?
Date: Thu, 20 Aug 1998 23:51:16

All:

There seems to be a lot of activity on the west coast of Canada relating to
the Earthquake preparedness programs and various public media releases
relating to an incipient large magnitude event. We have received in our
last telephone bill from BC Tel a pocket earthquake guide, with survival
tips and telephone numbers. This is all very good, as heightened awareness
and specific measures might lead to a greater survivability in the
aftermath of this coming event. 

There are also rumours here that the US military are moving personnel and
equipment away from the west coast in anticipation of this large quake. Can
anyone comment on this?

Thanks

Dean Sevold
dsevold@..............


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: Gregory Bajuk 
Subject: Computer interfacing
Date: Fri, 21 Aug 1998 10:03:21 -0700 (PDT)

For anyone interested in the basic methods of computer interfacing to the
outside world there is an interesting web site,  www.boondog.com  

Subjects on this site include building a parallel port interface box,
building an 8255 programmable peripheral interface card, and programming
custom hardware in visual basic.

Greg Bajuk  


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From: John Hernlund 
Subject: Re: Earthquake Hysteria?
Date: Fri, 21 Aug 1998 11:03:24 -0700 (MST)

On Thu, 20 Aug 1998, d.sevold wrote:
> There are also rumours here that the US military are moving personnel and
> equipment away from the west coast in anticipation of this large quake. Can
> anyone comment on this?

   Well, such an event can't really be predicted but maybe they are becoming
aware themselves.  I'll bet they have some items that would be hazardous to
everyone around if they were to be damaged during a quake; I would be
surprised if they did not!  

******************************************************************************

			       John Hernlund
     		          E-mail: hernlund@.......
      WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/
		    http://www.public.asu.edu/~hernlund/

"It is easier to excuse an ignorant person who claims that theory is
unnecessary and dispensable in his supposed practice, than to excuse a
Sophist who concedes its value to the schools (as, perhaps, only a mental
exercise) but who at the same time maintains that matters are quite
different in practice- that as one leaves school to enter the world, one
will realize one has been pursuing empty ideals and philosophical dreams-
and, in a word, that what sounds good in theory is of no practical
use."
-Immanuel Kant, On the Proverb: That May be True in Theory, But Is of No
Practical Use

******************************************************************************


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Public Seismic Network Mailing List (PSN-L)


From: John Rollins 
Subject: Re: Earthquake Hysteria?
Date: Fri, 21 Aug 1998 14:31:27 +1200

>There seems to be a lot of activity on the west coast of Canada relating to
>the Earthquake preparedness programs and various public media releases
>relating to an incipient large magnitude event. We have received in our
>last telephone bill from BC Tel a pocket earthquake guide, with survival
>tips and telephone numbers. This is all very good, as heightened awareness
>and specific measures might lead to a greater survivability in the
>aftermath of this coming event.
I can't say I blame them. That entire area from the bottom of Puget Sound
to the tip of Vancouver Islands isn't exactly a quite area. Enough large
quakes in the past, and a bunch of smaller ones in the past few years. Last
time I was up on Vancouver Islands, there was a quake between the island
and the mainland... A small one, but it WAS an quake. Or maybe just a
submarine that lost it's way and ran into a seismograph? ;-)


>There are also rumours here that the US military are moving personnel and
>equipment away from the west coast in anticipation of this large quake. Can
>anyone comment on this?
Almost funny! Just imagine trying to move the navy, army and air force
bases. Just too much to move and nowhere to go with it all. Do you really
think they would give up on everything down in California and surrounding
states? The San Andreas hasn't scared 'em out yet, I don't think much of
anything will. And where would they move everything to from Puget Sound?
There's TONS of stuff up there. Premanent moves are pretty much out of the
question(although not completely impossible, considering the shuffling down
in CA with the Marines and Navy), and as for temporary moves, I can't
undestand why. Since when does the US military predict earthquakes? Or are
they thinking of setting off something to trigger one? Oh, and while you're
at it go line your head with aluminum foil to keep the CIA brain scanners
out...

--------------------------------------------------------------
| http://members.tripod.com/~jrollins/index.html - Computers |
| http://www.geocities.com/Area51/Lair/1681/ - Star Trek     |
|   Orham@....... list admin                KD7BCY           |
--------------------------------------------------------------



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From: Doug Crice 
Subject: Re: Earthquake Hysteria?
Date: Fri, 21 Aug 1998 16:48:05 -0700

There was a really large earthquake just offshore Vancouver about 300
years ago.  Recently dated by looking at the Tsunami records from Asia. 
I have a friend with the Canadian Geological Survey measuring
near-surface shear wave velocities for ground spectral response
studies.  He says there is a high degree of horizontal anisotrophy in
the Frasier Delta aluvial deposits related to that earthquake.

The theory is that you measure the shear and P wave velocities near the
surface, add density, and construct a computer model to predict how the
ground will shake in relation to the earthquake (in other words, what
frequencies get amplified by the earth-jello).  Then, a good structural
engineer designs the building to shake at different frequencies.  In
this case, you would design it to shake different in different
directions (but of course it will probably liquify and it won't matter).
-- 
Doug Crice          web site http://www.georadar.com
GeoRadar Inc.             e-mail dcrice@............
19623 Via Escuela Drive           phone 408-867-3792
Saratoga, CA 95070 USA              fax 408-867-4900



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From: taber@............. (John Taber)
Subject: PSN/School presentations at AGU
Date: Sat, 22 Aug 1998 15:13:52 +1200

Ed, Ted, and Jan,

Ed recently suggested people submit PSN related posters to the
up coming AGU session on  Digital Communications in Seismology.
That's a very good idea, but for those whose focus is more on
seismology education, there is now an option of a session
devoted to seismology education.

Catherine Johnson at IRIS (catherine@......... wrote:

>I have received several enquiries over the past few days from
>people who are interested in submitting seismology education
>related abstracts to the Fall AGU. If there are sufficient
>abstracts submitted there will be a dedicated session.
>I strongly encourage you to submit education-related abstracts
>if possible.   If you do submit an abstract
>please send me the title, author list and text of your abstract
>by email.  Please pass this information along to
>any of your colleagues whom you think may be interested in
>submitting seismology education/outreach abstracts.
  
John Taber


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From: Edward Cranswick 
Subject: Re: Earthquake Hysteria?
Date: Fri, 21 Aug 1998 22:24:57 -0600

Doug-
    I have spent a day or so a couple of times being dragged through the
tidal flats around Seattle by some geologists looking for thin sand layers
interbedded with the peats. These sands are indicative of tsunamis which in
turn imply the occurrence of large earthquakes. However, I don't understand
the relationship between the anisotropy and earthquake.
-Edward

Doug Crice wrote:

> There was a really large earthquake just offshore Vancouver about 300
> years ago.  Recently dated by looking at the Tsunami records from Asia.
> I have a friend with the Canadian Geological Survey measuring
> near-surface shear wave velocities for ground spectral response
> studies.  He says there is a high degree of horizontal anisotrophy in
> the Frasier Delta aluvial deposits related to that earthquake.
>
> The theory is that you measure the shear and P wave velocities near the
> surface, add density, and construct a computer model to predict how the
> ground will shake in relation to the earthquake (in other words, what
> frequencies get amplified by the earth-jello).  Then, a good structural
> engineer designs the building to shake at different frequencies.  In
> this case, you would design it to shake different in different
> directions (but of course it will probably liquify and it won't matter).
> --
> Doug Crice          web site http://www.georadar.com
> GeoRadar Inc.             e-mail dcrice@............
> 19623 Via Escuela Drive           phone 408-867-3792
> Saratoga, CA 95070 USA              fax 408-867-4900
>
> _____________________________________________________________________
>
> 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: Doug Crice 
Subject: Re: Earthquake Hysteria?
Date: Fri, 21 Aug 1998 22:11:04 -0700

Ed,

I may be all wet, but consider the Frasier Delta as one big landslide. 
When the earthquake comes, the earth slumps toward the sea, and so the
shear strength in the direction of the epicenter is different than the
shear strength transverse.

In the San Francisco, you see anisotrophy in the bay muds, but we
thought this was tectonic.

When you reflect on the above, there's no clear case for either
mechanism in either site.  It might be more scientifically objective to
just say that the shear strength varies with azimuth because of the way
the ground moves and not try and assign the motion to short events
during earthquakes as opposed to slow creep in the absence of more
information/knowledge.
-- 
Doug Crice          web site http://www.georadar.com
GeoRadar Inc.             e-mail dcrice@............
19623 Via Escuela Drive           phone 408-867-3792
Saratoga, CA 95070 USA              fax 408-867-4900


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: "d.sevold" 
Subject: Military seismometers
Date: Fri, 21 Aug 1998 22:58:11

John Rollins wrote:
> Since when does the US military predict earthquakes? Or are
>they thinking of setting off something to trigger one? Oh, and while you're
>at it go line your head with aluminum foil to keep the CIA brain scanners
>out...
>

While living here in the Gulf Islands, I met a man, now retired, who
installed seismometers in an abandoned lead-zinc mine just about 5 miles
SSE of Flin Flon, Manitoba, on the road to Denare Beach, Saskatchewan. The
location is within the Precambrian Shield close to the Paleozoic limestones
to the south. The date of the installation was 1962. The installation was
done by a US company under contact to the US military. There was no
documentation given to the contractor, too hush-hush. Anyone care to
speculate on the type of equipment installed?

Flin Flon is my hometown. I remember the no tresspassing signs going up at
that mine road, by order of Department of National Defence. 

Should I be grounding out that aluminum helmet?



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From: Edward Cranswick 
Subject: Re: PSN/School presentations at AGU
Date: Sat, 22 Aug 1998 00:31:29 -0600

John-
    Thank you for the info from Catherine Johnson.  I agree with you that
the education session would be more appropriate for the Almaden School/PSN
AGU poster that we have discussed.
-Edward

John Taber wrote:

> Ed, Ted, and Jan,
>
> Ed recently suggested people submit PSN related posters to the
> up coming AGU session on  Digital Communications in Seismology.
> That's a very good idea, but for those whose focus is more on
> seismology education, there is now an option of a session
> devoted to seismology education.
>
> Catherine Johnson at IRIS (catherine@......... wrote:
>
> >I have received several enquiries over the past few days from
> >people who are interested in submitting seismology education
> >related abstracts to the Fall AGU. If there are sufficient
> >abstracts submitted there will be a dedicated session.
> >I strongly encourage you to submit education-related abstracts
> >if possible.   If you do submit an abstract
> >please send me the title, author list and text of your abstract
> >by email.  Please pass this information along to
> >any of your colleagues whom you think may be interested in
> >submitting seismology education/outreach abstracts.
>
> John Taber
>
> _____________________________________________________________________
>
> 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: Greg 
Subject: Re: Military seismometers
Date: Sat, 22 Aug 1998 10:34:57 -0700

d.sevold wrote:
> 
> John Rollins wrote:
> > Since when does the US military predict earthquakes? Or are
> >they thinking of setting off something to trigger one? Oh, and while 

Check out:
http://www.tbe.com/products/geotech/geotech.html

I did not write the page, but it appears vaguely related to the topic.

,Greg

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From: John Hernlund 
Subject: Re: Earthquake Hysteria?
Date: Sat, 22 Aug 1998 18:12:07 -0700 (MST)

On Fri, 21 Aug 1998, Doug Crice wrote:
> He says there is a high degree of horizontal anisotrophy in
> the Frasier Delta aluvial deposits related to that earthquake.

    Anisotropy???  I am not sure I understand what you mean here; could be
interesting.  It seems that shaking should lead to isotropy and
randomness...  

******************************************************************************

			       John Hernlund
     		          E-mail: hernlund@.......
      WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/
		    http://www.public.asu.edu/~hernlund/

"It is easier to excuse an ignorant person who claims that theory is
unnecessary and dispensable in his supposed practice, than to excuse a
Sophist who concedes its value to the schools (as, perhaps, only a mental
exercise) but who at the same time maintains that matters are quite
different in practice- that as one leaves school to enter the world, one
will realize one has been pursuing empty ideals and philosophical dreams-
and, in a word, that what sounds good in theory is of no practical
use."
-Immanuel Kant, On the Proverb: That May be True in Theory, But Is of No
Practical Use

******************************************************************************


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: John Hernlund 
Subject: Re: Earthquake Hysteria?
Date: Sat, 22 Aug 1998 18:24:27 -0700 (MST)

On Fri, 21 Aug 1998, Doug Crice wrote:
> I may be all wet, but consider the Frasier Delta as one big landslide. 
> When the earthquake comes, the earth slumps toward the sea, and so the
> shear strength in the direction of the epicenter is different than the
> shear strength transverse.
> In the San Francisco, you see anisotrophy in the bay muds, but we
> thought this was tectonic.

   I am wondering about the mechanism for aligning crystals in a mud.  I know
that in a hot system (e.g. upper mantle) shearing can have an impact on the
thermodynamics controlling crystal growth and cause them to line up in a
certain direction by making that the best energy path for growth.  Stresses
transmitted in a clast supported sedimentary structure have similar effects
whose speed depends on heat and the magnitude of the stress.  Maybe in a mud
minerals like phyllosilicates can rotate under shearing conditions until a
good slip-fit is achieved by flat crystals lying flat one on top of the
other...  This seems flimsy though, and if it does exist I would most
definitely choose tectonic stress as being the culprit because it is more
consistent over very long periods of time; earthquakes are too brief and the
stresses are very small and more random. 

******************************************************************************

			       John Hernlund
     		          E-mail: hernlund@.......
      WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/
		    http://www.public.asu.edu/~hernlund/

"It is easier to excuse an ignorant person who claims that theory is
unnecessary and dispensable in his supposed practice, than to excuse a
Sophist who concedes its value to the schools (as, perhaps, only a mental
exercise) but who at the same time maintains that matters are quite
different in practice- that as one leaves school to enter the world, one
will realize one has been pursuing empty ideals and philosophical dreams-
and, in a word, that what sounds good in theory is of no practical
use."
-Immanuel Kant, On the Proverb: That May be True in Theory, But Is of No
Practical Use

******************************************************************************


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: Edward Cranswick 
Subject: [Fwd: PSN related abstract]
Date: Sat, 22 Aug 1998 19:33:38 -0600

John-
    After thinking about this mail last night, I am taking the liberty
of forwarding it to the PSN-L because it contains alot of info pertinent
to PSN with respect to the upcoming AGU abstract deadline.
-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".

John-
    I went through the QT website in some further detail, and it is
quite a promising beginning you have there to be used in conjunction
with the 5-6 schools you plan to have online this year (I like the
modulated wavetrain seismogram!). It was a long web trip that ended up
in LA with the Loma Prieta EQ, and it will be good to see when you have
got all the NZ ducks in a row on the Web. It must be nice to have some
young talent like Tim to do things like ActiveX.  At 47, I am one of the
"young dudes" at USGS Golden, and I don't anticipate jumping through too
many more of Bill Gates' hoops in this lifetime. I am impressed by your
book, and want to order a copy so that I can have a gander. It's
interesting that both you and Martha Savage, with whom I worked at the
Nevada Test Site during our aftershock investigation of the Little Skull
Mountain EQ (induced(?) a day after the1992 Landers EQ), are from
Swarthmore, one of the many colleges by which I was rejected for my
freshman year in 1969 ...
    Anyway, the abstract sounds good (you are welcome to that sentence
which I undoubtedly lifted from someone else), and I think that the
proposed special education session would be appropriate for it and the
abstract that I hope Ted & Jan will submit for the Almaden School.
However, though it is a bit of a moot point if noone submits a general
PSN abstract, I think the Digital Communications in Seismology session
is more appropriate for the essence of the way that the PSN has come to
operate.  Nearly (virtually?) all other networks are monitored by
several staff members who are concentrated together in one or two
offices, and these individuals have each other to share results with,
etc.  By contrast, each PSN seismograph station is a one-person
operation and, perforce, must rely upon digital communicatons to
function effectively. The unity of the PSN depends upon the Web/Internet
(courtesy of Larry Cochrane) in a way that we never anticipated back in
the old San Jose PSN BBS days, not to mention the history of previous
amateur analogue seismology organiztions, now defunct.
-Edward

John Taber wrote:

> Ed,
>
> I've put together a draft abstract for AGU and I'd appreciate any
> comments.  I hope it's ok that I used a sentence from your
> abstract last year to describe the PSN.  Do you think I should
> mention specific PSN members in the abstract?
>
> I received the following from Catherine Johnson at IRIS , and I
> think that might be a better place to submit PSN related
> seismology education absracts.  What do yiou think?
>
> >Dear all,
> >
> >I have received several enquiries over the past few days from
> >people who are interested in submitting seismology education
> >related abstracts to the Fall AGU.  Please note that there
> >are no special seismology sessions in education arranged for
> >the Fall AGU.  AGU's current policy is to run Education sessions
> >primarily at the Spring AGU.  However, I just talked with Steve
> >Grand who is the program chair for the Fall AGU seismology
> >program.  He is happy to accept education-related abstracts
> >and if there are sufficient submitted he will make a dedicated
> >session.  Unfortunately, unlike for the Spring AGU you are only
> >allowed
> >one first author contributed abstract (At Spring AGU two first
> >author contributed abstracts were permitted as long as one was
> >research-related and one education-related).  Remember, however
> >that the first author need not be the presenting author so one
> >can be creative in finding ways around this rule....
> >
> >I strongly encourage you to submit education-related abstracts
> >if possible.  For those of you involved in research
> >but also pursuing various education/outreach efforts,
> >recognition
> >of these education efforts by the same community that recognizes
> >your research is extremely important.  If you do submit an
> >abstract
> >please send me the title, author list and text of your abstract
> >by email - Steve Grand asked me to pass on a list of abstracts
> >which I know to have been submitted to help him sorting through
> >everything.  With some coordination we should be able to get at
> >least one dedicated sessions.  Please pass this information
> >along to
> >any of your colleagues whom you think may be interested in
> >submitting
> >seismology education/outreach abstracts.
> >
> >Thanks!
> >
> >Catherine Johnson
>
> -------
>
> Below is my draft abstract.
>
> Cheers,
>
> John
>
> Quake Trackers - A new high school seismology program in New Zealand
>
> John Taber, School of Earth Sciences, Victoria University of
> Wellington, PO Box 600, Wellington, New Zealand,
> John.Taber@.........
>
> Michael Kozuch, Institute of Geological and Nuclear
> Sciences, PO Box 30-368, Lower Hutt, New Zealand,
> m.kozuch@..........
>
> A new seismology education program has been established in
> New Zealand based on the Princeton Earth Physics project
> (PEPP), using low-cost data acquisition and analysis
> software developed by members of the Public Seismic Network
> (PSN).  The project has involved local teachers, students
> (high school to graduate level) and amateur seismologists
> and shows how seismology education modules can easily be
> shared internationally.
>
> We are following PEPP's model of curriculum pages and an
> online waveform database to be shared among all schools
> (including those without a seismograph of their own).
> PEPP's curriculum pages have been modified slightly to make
> them more applicable to NZ and additional modules are under
> development  based around the PSN software. Schools without
> a seismograph of their own can also view a near-real-time
> seismograph on the the website.
>
> The PSN is a rapidly growing  international group of amateur
> seismologists concentrated in California, who record data
> with their own digital seismographs and exchange waveform
> data and communicate to each other via the Internet.  The
> PSN hardware and software we are using has been developed by
> Larry Cochrane and tested in New Zealand by Dave Nelson.
> Each seismograph will consist of a 3-component 4.5 Hz
> sensor, 16 bit A/D board, gps timing  with recording on a
> dedicated 386 or 486 PC.  The low cost of the system means
> it is affordable for a large number of schools and for
> interested members of the public.  The cost has been kept
> low by using the PSN hardware and software and relatively
> high frequency sensors that are adequate for recording local
> and regional seismicity.
>
> Five to six schools will have seismographs by the end of the
> year.  The first year network is concentrated in the
> Wellington region with a few schools distributed throughout
> the country.  The initial schools have been chosen to sample
> a variety of site conditions so that the data can be used
> for site response research.
>
> The initial funding for the project has come from the NZ
> Earthquake Commission, which is the national earthquake
> insurance company for NZ.  Their involvement recognizes that
> public earthquake education can reduce earthquake damage.
>
> The Quake Trackers home page can be found at
> http://www.geo.vuw.ac.nz/seismology/Quake_Trackers/.



--
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: Robert Avakian 
Subject: Re: Earthquake Hysteria?
Date: Sat, 22 Aug 1998 20:52:27 -0700

Perhaps the surface waves compact unconcolidated soils in the direction
normal to their propogation?  If the locations of the epicenters of all
the significant quakes were far enough or restricted enough, the
compaction might look unidirectional.  There are some pretty weird
happenings in unconsolidated soils during and after quakes.   Or am I
totally off base??

Bob



John Hernlund wrote:
> 
> On Fri, 21 Aug 1998, Doug Crice wrote:
> > He says there is a high degree of horizontal anisotrophy in
> > the Frasier Delta aluvial deposits related to that earthquake.
> 
>     Anisotropy???  I am not sure I understand what you mean here; could be
> interesting.  It seems that shaking should lead to isotropy and
> randomness...
> 
> ******************************************************************************
> 
>                                John Hernlund
>                           E-mail: hernlund@.......
>       WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/
>                     http://www.public.asu.edu/~hernlund/
> 
> "It is easier to excuse an ignorant person who claims that theory is
> unnecessary and dispensable in his supposed practice, than to excuse a
> Sophist who concedes its value to the schools (as, perhaps, only a mental
> exercise) but who at the same time maintains that matters are quite
> different in practice- that as one leaves school to enter the world, one
> will realize one has been pursuing empty ideals and philosophical dreams-
> and, in a word, that what sounds good in theory is of no practical
> use."
> -Immanuel Kant, On the Proverb: That May be True in Theory, But Is of No
> Practical Use
> 
> ******************************************************************************
> 
> _____________________________________________________________________
> 
> Public Seismic Network Mailing List (PSN-L)
> 
> To leave this list email listserver@............. with the body of the
> message: leave PSN-L


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From: meredith lamb 
Subject: quake rolling in now
Date: Sun, 23 Aug 1998 08:21:05 -0600

P seems to be long period....perhaps a fair distant large quake.

meredith lamb




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From: barry lotz 
Subject: Re: quake rolling in now
Date: Sun, 23 Aug 1998 08:59:58 -0700

Meredith
   Red puma says central america but not specific.
                                     Barry

meredith lamb wrote:
> 
> P seems to be long period....perhaps a fair distant large quake.
> 
> meredith lamb
>

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From: barry lotz 
Subject: New event
Date: Sun, 23 Aug 1998 09:16:07 -0700

All
  Sorry, the distances on the latest event I uploaded are screwed up.
The new version of winquake doesn't have the distance shown next to the
epicenter coordinates so I tend to forget to correct the distance on the
file description. I leave a place for the distance with an arbitrary
number and correct it later.
                                         Regards
                                          Barry

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From: Greg 
Subject: sound card oscope
Date: Sun, 23 Aug 1998 11:08:19 -0700

I found this little program a while ago and I've sort of forgot to
download the library I need to install it since. I got the library
yesterday and it installed it and ran it. It's been so long since I even
touched an oscope that I forgot about all of the controls. I got it
connected to the audio from the CD-ROM and later the geophone (while I
shook it up and down a little) and made a couple of screen shots. These
are under X Windows with Linux, but I think the program is also
available for other Unices. I know the library was written for Silicon
Graphics computers. The program reads from /dev/dsp or a Radio Shack
ProbeScope /dev/probescope connected to the serial port. So if you have
a UNIX computer, you'll need read access to the device. I think I
remember a similar DOS program.

Someone mentioned hitching a geophone up to a real oscope, but this is
slightly closer to what I WANTED to do. Speaking of which I decided that
I'll probably just save my pennies and get a DataQ DI-1xxxx thingy or a
Larry C. DA board. I did manage to get some 16 bit unsigned integers
from the soundcard, but you do have to throw away a lot of data in order
to get the file size down. If I used Norman's? VCO circuit the sampling
rate will have to be higher also (so the files won't shrink). The
official word from Creative Labs is 15 Hz lowest sampling frequency for
their soundcards. I actually got a reply from my email to them. BTW
sound card programming at this level is a little easier under Linux. At
least with the samples that I found. It's very computer intensive to
record like I wanted to, so a 386 might not cut it. At least not with
the sloppy code I was writing.

Music 2 channels right and left from CD-ROM drive:
http://www.treefort.org/~ghost/scope.gif

Single channel music left channel? from CD-ROM drive:
http://www.treefort.org/~ghost/scope1.gif

Single channel geophone in line in of soundcard:
http://www.treefort.org/~ghost/scope2.gif

I got the program and library here:
http://rufus.w3.org/linux/RPM/

So I guess that's it,
Greg

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From: Doug Crice 
Subject: Re: Earthquake Hysteria?
Date: Sun, 23 Aug 1998 17:18:49 -0700

Isotrophy is, I guess, uniform in all directions, so anisotrophy means
the physical properties vary depending on the direction they are
measured.

In the shear wave case,  we measure the shear wave velocity down a
borehole (by measuring the time it takes for a transverse sledgehammer
impact to propagate down into the ground).  By doing it at a number of
points, you can measure the shearwave velocity at different depths.  You
might clamp your geophone in the borehole every five feet say, until you
get to "rock like material" which becomes the source of vibrations from
an earthquake which are amplified by the sediments, thus collapsing
buildings.

Anisotrophy in the case, means that the shear wave velocities are
different in different azimuths.  For example, NS velocities would be
different than EW.  This is a rather esoteric subset of aseismic design.

In the unlikely event anybody wants to see a downhole geophone, photos
are on my website at http://www.georadar.com/geophone.htm

The spring expands to clamp the geophone against the wall of the
borehole so you can sense the horizontal motion.
-- 
Doug Crice          web site http://www.georadar.com
GeoRadar Inc.             e-mail dcrice@............
19623 Via Escuela Drive           phone 408-867-3792
Saratoga, CA 95070 USA              fax 408-867-4900


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From: "Charles R. Patton" 
Subject: Possible source for micrometer leveling screws
Date: Mon, 24 Aug 1998 11:08:13 -0700

As I was wandering, I came across this URL:
http://www.mermac.com/deals.html
with this ad:
*********
0-1" Micrometers (China) 
These are rather crude, but seem to be accurate to .001". They are great
to use as "beaters" around the shop. Throw
one in your toolbox, one in the glove compartment of your car, and don't
forget to give one to your Gorilla-like
neighbor or friend who is always using your nice Starrett mike as a
C-clamp! 
Regular Price: $???? 
SALE: $6.00 ea. for singles, $5.00 ea. for 2 or more
*********
This may be just the ticket for your leveling screws in your
seismometers.

I've never done business with this company -- I'm just posting it FYI.

Charles R. Patton

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Public Seismic Network Mailing List (PSN-L)


From: watson@................ (Charles Watson)
Subject: [Fwd: WARNING: Arrival of Energetic Protons Expected - 24/25 August]
Date: Mon, 24 Aug 1998 16:29:44 -0700

here it comes...

-- 
---/----
Charles P. Watson
Seismo-Watch

From: watson@................ (Charles Watson)
Subject: [Fwd: WARNING: >100 MEV PROTONS ARE BEGINNING TO ARRIVE]
Date: Mon, 24 Aug 1998 16:31:17 -0700

Its upon us now..

-- 
---/----
Charles P. Watson
Seismo-Watch

From: Doug Crice 
Subject: Re: [Fwd: WARNING: >100 MEV PROTONS ARE BEGINNING TO ARRIVE]
Date: Mon, 24 Aug 1998 16:55:21 -0700

Charles,

I find the proton warnings rather interesting, but haven't been around
enough to understand the significance.  Should I go to the archives or
more information or just stay indoors, or perhaps carry an umbrella when
outside? :)

Seriously, how about a short briefing on physical effects.

Thanks,
-- 
Doug Crice          web site http://www.georadar.com
GeoRadar Inc.             e-mail dcrice@............
19623 Via Escuela Drive           phone 408-867-3792
Saratoga, CA 95070 USA              fax 408-867-4900


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: watson@................ (Charles Watson)
Subject: Re: [Fwd: WARNING: >100 MEV PROTONS ARE BEGINNING TO ARRIVE]
Date: Mon, 24 Aug 1998 17:39:48 -0700

Doug Crice wrote:
> 
> Charles,
> 
> I find the proton warnings rather interesting, but haven't been around
> enough to understand the significance.  Should I go to the archives or
> more information or just stay indoors, or perhaps carry an umbrella when
> outside? :)
> 
> Seriously, how about a short briefing on physical effects.
> 
> Thanks,
> --
> Doug Crice 


In the ol' days, many of the PSN people were ham radio operators as well as 
seismo-zons. These proton bursts usually disrupt short wave radio signels, 
sometimes to a point of totally reducing their usefulness during peak levels.

If you are a satelite owner, you may want to be concerned about communicating 
with your baby in space.

Geomagnitism also goes wonkers in large proton burst.

Although not conclusive, there has been some correlations between solar flares 
and earthquake activity. I say this weakly because I am only now accumulating 
references to this regard. The data does seem rather tenuious but when you're 
in the business in reporting on earthquakes, active periods, as well as 
inactive periods, are important to know about so one can plan vacations, 
computer repairs, etc., accordingly. 

Really? Just another geophysical phenomenon to watch and see what happens.


-- 
---/----
Charles P. Watson
Proton-Watch

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Public Seismic Network Mailing List (PSN-L)


From: watson@................ (Charles Watson)
Subject: [Fwd: ALERT: Solar Proton Event Alert at > 10 MeV]
Date: Mon, 24 Aug 1998 17:41:07 -0700

here is the latest Solar Alert Bulletin.

I promiss, this will be the last.

-- 
---/----
Charles P. Watson
Proton-Watch

From: Jim Hannon 
Subject: Re: [Fwd: WARNING: >100 MEV PROTONS ARE BEGINNING TO ARRIVE]
Date: Mon, 24 Aug 1998 19:54:44 -0500

Doug Crice wrote:
 >
 > Charles,
 >
 > I find the proton warnings rather interesting, but haven't been
around
 > enough to understand the significance.  Should I go to the archives
or
 > more information or just stay indoors, or perhaps carry an umbrella
when
 > outside? :)
 >
 > Seriously, how about a short briefing on physical effects.
 >
 > Thanks,
 > --
 > Doug Crice

It means I should go out and look for Northern Lights tonight, but it
looks too cloudy drats. :) 

-- 
Jim Hannon
http://soli.inav.net/~jmhannon/
42,11.90N 91,39.26W
WB0TXL


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From: barry lotz 
Subject: Guatemala
Date: Mon, 24 Aug 1998 18:18:23 -0700

To all
   My records of the Guatemala event had minor epicentral data errors
and the distance from my station is incorrect. I miss having the
distance show up next to the epicentral coordinates in the latest
version of winquake. I just have to remember to correct the distance
space I leave with an arbitrary distance in the description line. I
posted this message yesterday but got a delivery error message so I'm
sending it again. If it went thru, sorry for the repeat.
                                         Barry

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Public Seismic Network Mailing List (PSN-L)


From: Clark Wockner 
Subject: Clark's new address
Date: Mon, 24 Aug 1998 22:50:51 -0500

Hi everyone:
    I have changed providers and my new address will be----
< clark@................. >
Thanks ,  Clark Wockner
                W9RWX


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From: Ted Blank 
Subject: Abstract for AGU Poster Session
Date: Mon, 24 Aug 1998 21:44:55 -0700 (PDT)


Edward,

Here is what I have come up with for the abstract.  I was thinking that 
one teacher and 2 students could man the poster for shifts of (say) 2 
hours, then another couple of students could take over.  Usually there 
are just a handful of students in the class who get excited about 
operating the station, so between Almaden Country School and South Valley 
Junior High School maybe 10-12 students total would be chosen...

Last year when I visited Larry and your poster session, I imagined that 
if we did a student session, the participants would get two benefits.  
First the experience of putting together the poster and display data from 
their own data.  Second, the opportunity to stroll around (chaperoned by 
teachers/parents) and see how the other scientists in the poster session 
have presented their work.

I was imagining the poster itself in two parts.  One half would be based 
on what they have learned about the structure of the earth and the 
mechanisms which generate earthquakes.  The other half would be the 
results of their classroom monitoring - actual seismograms, P- and S-wave 
phase identifications, tied to a map of the earth showing the location of 
the quakes.

Anyway, let me know what you think.
-=-=-=-= Start of Abstract -=-=-=-=
Seismic Monitoring in the Classroom-  A Complement to the Traditional 
Middle School Earth Science Curriculum

For several years the Public Seismic Network (PSN) has supported several 
amateur seismic monitoring stations in Middle School science classrooms 
in the San Francisco Bay Area. Software, hardware and training are 
donated by the PSN.  Two of the longest-running stations are at Almaden 
Country School (6835  Trinidad Drive, San Jose 95120) and South Valley 
Junior High School of Science and Technology (385 I.O.O.F. Avenue, Gilroy 
95020) .
Near the beginning of 
each school year a member of the PSN visits the school and provides the 
students and teachers with an overview of the station hardware and 
software.  During the remainder of the school year the students and 
teachers operate the station in conjunction with the earth science 
curriculum at the school.  Significant local and teleseismic events which 
pass the software triggering filter are analyzed and  P- and S-wave phase 
times are used to calculate the epicentral distance.  Results are checked 
for accuracy against USGS data from the World Wide Web.  Quake locations 
are tracked on small- and large-scale maps and students are encouraged to 
keep accurate station records.  Data collected at the school stations is 
uploaded to the PSN web site (http://psn.quake.net) and data from other 
PSN stations around the world is downloaded to provide the students with 
enough records to perform accurate triangulation of epicentral locations 
for large events.  Operation of a classroom PSN station provides students 
with the opportunity to participate in an unusual and direct hands-on 
Earth Science activity which, it is hoped, gives them a more solid 
foundation on which to anchor the information they will be receiving 
during the course of the year as they study the structure of the earth.  
Students also learn the frustrations associated with "real science" - the 
importance of accurate record keeping, lost/missing/poor quality data, 
hardware and software problems, etc.  This poster session will be manned 
by students and teachers from both schools who have participated in the 
operation of the classroom station during the course of the school year.  
It will consist of a review of the seismic data collected in the 
classroom and student interpretations of how that data fits in with 
current models of the structure of the earth.
 
-=-=-=-= End of abstract -=-=-=-=-=

Ted Blank
San Jose, California


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From: Edward Cranswick 
Subject: Re: Problems with USGS finger server...
Date: Mon, 24 Aug 1998 23:09:15 -0600

Ken-
    Are you a friend of Bill W. (as they say)?  I was just reading your
excellent review of "Homebuilt Seismograph - FAQ" and noticed that it was
signed "Seismoholic". You also made an interesting remark at the PSN meeting
at USGS last December to the effect that "PSN should never be organized", and
that got my attention. I have been in the program for the last five years --
I always realize I have a drinking problem when I wake up married, and after
a 9-year hiatus, I started drinking vodka in Moscow so I ended up with a
Russian wife -- and the parallels between PSN and the former have always been
striking, perhaps in part because of Ben Gardner who I bamboozled into
getting involved with PSN and who 12th-stepped me in revenge.
-Edward

Ken Navarre wrote:

> Anyone else notice that the finger server for quake@................. has
> been down for a couple of days now?
>
> 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".



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From: Fred and Tina 
Subject: Geophone ? 
Date: Mon, 24 Aug 1998 23:47:26 -0700

I have a couple of geophones from Geosource INC (MD-79)   It is buried
about 3FT down, inside a 1PT paint can filled with dry sand. I seem to
be picking up alot of local noise. ie:Cars, kids running, etc.   

My question is, how far down do I need to go to reduce this garbage to
an acceptable level. 

Also, Does anyone else get large DC offsets with the DI150RS in the X100
setting. Could I replace the internal reff with a temp/compensated reff
?  

Fred

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Public Seismic Network Mailing List (PSN-L)


From: 
Subject: Re: Geophone ?
Date: Tue, 25 Aug 1998 08:09:17 EDT

If it is practical, put your geophone at or slightly below the top of the
water table.  In many places this is about 15-20 feet below the surface. A
rule of thumb is that the velocity of sound below the water table is 6000
ft/sec and above is 2000 ft/sec.  This velocity contrast mirriors much of the
seismic energy back.  Lots of your surface noise will be greatly attenuated.

In a message dated 98-08-25 02:46:48 EDT, you write:

<< 
 I have a couple of geophones from Geosource INC (MD-79)   It is buried
 about 3FT down, inside a 1PT paint can filled with dry sand. I seem to
 be picking up alot of local noise. ie:Cars, kids running, etc.   
 
 My question is, how far down do I need to go to reduce this garbage to
 an acceptable level. 
  >>

George Erich
GeE777@.......
Seismic Exploration Consultant
Phone (562) 868-6013
P. O. Box 2011
Norwalk, CA 90651
33 - 53.87N
118 - 04.50W

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From: Ken Navarre 
Subject: Re: Philosophic detour...
Date: Tue, 25 Aug 1998 10:21:59 -0700 (PDT)

On Mon, 24 Aug 1998, Edward Cranswick wrote:

> Ken-
>     Are you a friend of Bill W. (as they say)?  I was just reading your
> excellent review of "Homebuilt Seismograph - FAQ" and noticed that it was
> signed "Seismoholic". 

Ahhhh yes, that quite adequately describes my passion for those times 
when the "earth moves..."

> You also made an interesting remark at the PSN meeting
> at USGS last December to the effect that "PSN should never be organized", and
> that got my attention. I have been in the program for the last five years --
> I always realize I have a drinking problem when I wake up married, and after
> a 9-year hiatus, I started drinking vodka in Moscow so I ended up with a
> Russian wife -- and the parallels between PSN and the former have always been
> striking, perhaps in part because of Ben Gardner who I bamboozled into
> getting involved with PSN and who 12th-stepped me in revenge.
> -Edward

I think I was repeating an oft heard concern of some of the "original 10" 
that if PSN were to be "organized" that it might become guided by some 
sort of "agenda".  Several of the "founders" felt that our common bond was 
nothing more than a support group created to help us non-professional 
seismo types pool info and tech support to allow us to view what the "big 
kids" get paid to do.  In *that* regard I think that PSN has been a 
tremendous success.  I have NEVER seen the likes of it... 
consider the development of such a network of curious, dedicated folks
who have pooled info and resources to replicate something that, formerly, 
only the gov't or educational institutions were able to do.  IT's pretty 
darned remarkable!!!  Many of us have more sophisticated data collection 
systems than some of the government sites have in some countries of the 
world... We're pretty lucky!

Personally, I have no real concern over a formal organization.  During 
the years that I have been a member of PSN I felt that I had some talents 
to offer but I have gladly stepped back into the woodwork as people with 
more skills have offered their services and input.  You see, I love our 
group and have no ego involvment in it.  By that I mean that I love the 
search for the elusive waves an not the search for recognition..  I think 
that some of the "concern" over "organization" came from valid 
observations from experiences with other groups in other disciplines that 
may have been driven by egos rather than curosity.

I have been impressed by the selflessness of the people who have 
"accepted the call" in the PSN group to take on responsibility with the 
absence of any self motivated agenda!  This is truely an amazing group of 
people and I am proud to be associated with all of you!


....ramblings from Ken Navarre
 

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From: Greg 
Subject: Commercial/government level
Date: Tue, 25 Aug 1998 11:48:11 -0700

I found some really neat data acquisition equipment on the DATAQ web
site and I thought someone with lots of money might want to know about
it. In other words government and commercial. 

There's a 16 bit 32 channel DA box that plugs into either a parallel
port, an USB port, or a ethernet port on a LAN. The last option has got
to be the most appropriate for seismo because with a fiber optic line
you could actually get some distance between instruments. Enough to see
different arrival times for the same event, without radios. The prices
are from $400 to over $2000.

I also thought of something a little cheaper. Use a fiber optic line
driver (Black Box) and a DI-150RS to put a little distance between the
computer and the instrument. I wonder if you can run two DI-150RSs on
the same computer? 4 channels with 2 miles between the instruments
sounds nice to me, but who has a two mile long backyard? Plus it's
optically isolated. Only thing is that you'd need power (solar) at each
instrument for the DI-150RS and amp(?).

One little question that's been sort of bugging me. What do the
commercial and government types use for software and hardware now? Is
the software custom written for every site around the world or is there
a standard program everyone uses? I know that some use fancy geophones
and real seismometers, but what about software, operating systems, data
transmission from the instruments to the computer, etc... There's one
site on the internet that shows the complete details about the
instrument location and how it was built, but I think it's a little
unique. 

I would guess that for one instrument physically seperated from the
computer for a little distance you'd need the instrument, amp/filter,
power, and a radio or wire. Something else?

,Greg

_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: "Michael R. Phillips" 
Subject: Re: Earthquake Hysteria?
Date: Tue, 25 Aug 1998 15:15:35 -0700



John Hernlund wrote:

> On Fri, 21 Aug 1998, Doug Crice wrote:
> > He says there is a high degree of horizontal anisotrophy in
> > the Frasier Delta aluvial deposits related to that earthquake.
>
>     Anisotropy???  I am not sure I understand what you mean here; could be
> interesting.  It seems that shaking should lead to isotropy and
> randomness...
>
> ******************************************************************************
>
>                                John Hernlund
>                           E-mail: hernlund@.......
>       WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/
>                     http://www.public.asu.edu/~hernlund/
>
> "It is easier to excuse an ignorant person who claims that theory is
> unnecessary and dispensable in his supposed practice, than to excuse a
> Sophist who concedes its value to the schools (as, perhaps, only a mental
> exercise) but who at the same time maintains that matters are quite
> different in practice- that as one leaves school to enter the world, one
> will realize one has been pursuing empty ideals and philosophical dreams-
> and, in a word, that what sounds good in theory is of no practical
> use."
> -Immanuel Kant, On the Proverb: That May be True in Theory, But Is of No
> Practical Use
>
> ******************************************************************************
>
> _____________________________________________________________________
>
> 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: Fw: Abstract for AGU Poster Session
Date: Tue, 25 Aug 1998 15:13:37 -0600


-----Original Message-----
From: Edward Cranswick 
To: Ted Blank 
Date: Monday, August 24, 1998 11:20 PM
Subject: Re: Abstract for AGU Poster Session


>Ted-
>    Based on a skimmed reading, I think the abstract is great. Now that the
>ball is in my court, I am busy checking out what I have to do to sponsor
its
>submission to AGU. I'll let you know more completely in a day or so.
>-Edward
>
>-----Original Message-----
>From: Ted Blank 
>To: psn-l@............. 
>Cc: cranswick@...................... 
>Date: Monday, August 24, 1998 10:45 PM
>Subject: Abstract for AGU Poster Session
>
>
>>
>>Edward,
>>
>>Here is what I have come up with for the abstract.  I was thinking that
>>one teacher and 2 students could man the poster for shifts of (say) 2
>>hours, then another couple of students could take over.  Usually there
>>are just a handful of students in the class who get excited about
>>operating the station, so between Almaden Country School and South Valley
>>Junior High School maybe 10-12 students total would be chosen...
>>
>>Last year when I visited Larry and your poster session, I imagined that
>>if we did a student session, the participants would get two benefits.
>>First the experience of putting together the poster and display data from
>>their own data.  Second, the opportunity to stroll around (chaperoned by
>>teachers/parents) and see how the other scientists in the poster session
>>have presented their work.
>>
>>I was imagining the poster itself in two parts.  One half would be based
>>on what they have learned about the structure of the earth and the
>>mechanisms which generate earthquakes.  The other half would be the
>>results of their classroom monitoring - actual seismograms, P- and S-wave
>>phase identifications, tied to a map of the earth showing the location of
>>the quakes.
>>
>>Anyway, let me know what you think.
>>-=-=-=-= Start of Abstract -=-=-=-=
>>Seismic Monitoring in the Classroom-  A Complement to the Traditional
>>Middle School Earth Science Curriculum
>>
>>For several years the Public Seismic Network (PSN) has supported several
>>amateur seismic monitoring stations in Middle School science classrooms
>>in the San Francisco Bay Area. Software, hardware and training are
>>donated by the PSN.  Two of the longest-running stations are at Almaden
>>Country School (6835  Trinidad Drive, San Jose 95120) and South Valley
>>Junior High School of Science and Technology (385 I.O.O.F. Avenue, Gilroy
>>95020) .
>>Near the beginning of
>>each school year a member of the PSN visits the school and provides the
>>students and teachers with an overview of the station hardware and
>>software.  During the remainder of the school year the students and
>>teachers operate the station in conjunction with the earth science
>>curriculum at the school.  Significant local and teleseismic events which
>>pass the software triggering filter are analyzed and  P- and S-wave phase
>>times are used to calculate the epicentral distance.  Results are checked
>>for accuracy against USGS data from the World Wide Web.  Quake locations
>>are tracked on small- and large-scale maps and students are encouraged to
>>keep accurate station records.  Data collected at the school stations is
>>uploaded to the PSN web site (http://psn.quake.net) and data from other
>>PSN stations around the world is downloaded to provide the students with
>>enough records to perform accurate triangulation of epicentral locations
>>for large events.  Operation of a classroom PSN station provides students
>>with the opportunity to participate in an unusual and direct hands-on
>>Earth Science activity which, it is hoped, gives them a more solid
>>foundation on which to anchor the information they will be receiving
>>during the course of the year as they study the structure of the earth.
>>Students also learn the frustrations associated with "real science" - the
>>importance of accurate record keeping, lost/missing/poor quality data,
>>hardware and software problems, etc.  This poster session will be manned
>>by students and teachers from both schools who have participated in the
>>operation of the classroom station during the course of the school year.
>>It will consist of a review of the seismic data collected in the
>>classroom and student interpretations of how that data fits in with
>>current models of the structure of the earth.
>>
>>-=-=-=-= End of abstract -=-=-=-=-=
>>
>>Ted Blank
>>San Jose, California
>>
>>
>>
>



_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: S-T Morrissey 
Subject: data acquisition systems
Date: Tue, 25 Aug 1998 17:10:27 -0500 (CDT)


Greg,

The scientific/seismological community uses about 5 or 6 commercial
data acquisition systems or products. They all essentially do the 
same thing: oversample the data at 24 bits resolution, decimate it 
to various channels with multiple sample rates with FIR filters, 
event detect on selected channels, and archive the data on disk 
and/or write it to tape, with some channels ported out to a 
satellite or spread-spectrum link. Usually only events are saved 
at higher sample rates (20 sps to 200 sps), but continuous archiving 
is done at slower rates (1 to 0,001 sps). For the nuclear test ban 
verification instruments, we archive the 40 sps data continuously,
lest someone allege that a clandestine event escaped the event detector.

All the systems write standard output files, the most common being
SEED (Standard for Environmental and Earthquake  Data ?) format, 
which is readily converted to others by SAC (Seismic Analysis Code).

All the IRIS high-gain stations use Quanterra digitizers/processors
running an operating system called SHEAR, so anyone in the world
can call and retrieve the data (part of the "open resource idea" for
the non-proliferation treaty). The French have a compatible process
in their GEOSCOPE stations. Even when a system seems to have many
special attributes, like the BDSN (Berkeley Digital Seismic Network),
they are mostly in the data transmission part. Even the BDSN station
on the Farallon islands is running a Quanterra system.

So there is little incentive to re-invent the wheel if one can
be bought at moderate cost. And having common hardware and software
is essential for handling data in extensive networks, even on
a global scale. The IRIS network has over 120 stations (look at:
http://www.iris.washington.edu/ ).

You ask about a site where the station processor is separated
from the sensors/digitizer. My station CCM is such, where the
sensors are in a cavern with a 9-channel, 24-bit digitizer, and
the data is sent via  a 3 km fiber optic to the state park visitor 
center where the processing, archiving, and satellite link are. 
The SHEAR operating system is operating at both ends of the fiber 
link, sharing instructions and timing  and data in real time.

regards,
Sean-Thomas

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Public Seismic Network Mailing List (PSN-L)


From: Charlie Rond 
Subject: Getting something-maybe microseisms
Date: Wed, 26 Aug 1998 02:29:02 -0500

All,

Getting something 7:29 UTC, is it microseisms?  From Bonnie?




 Charlie Rond     -\/\--Public Seismic Network-Memphis
                  http://gandlf.ceri.memphis.edu/~rond/psn        
  


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From: frankcnd@.......... (Frank Condon)
Subject: Need Source for mercury batteries
Date: Wed, 26 Aug 1998 00:22:46 -0700 (PDT)

Hello All:
I have a RFL 101 magnetometer that requires me to feed it some fresh 
batteries. There are two kinds installed in it. One is for the field 
compensation Gamma and is a Mallory 6.75 V, 1000mAH. The other two are for 
portable power and use Mallory 6.75V, 2200mAH. Any help would be greatly 
appreciated in locating a substitute or original.

Thanks,

Frank Condon


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Public Seismic Network Mailing List (PSN-L)


From: David Josephson 
Subject: Re: Need Source for mercury batteries
Date: Wed, 26 Aug 1998 01:44:51 -0700 (PDT)

> compensation Gamma and is a Mallory 6.75 V, 1000mAH. The other two are for 
> portable power and use Mallory 6.75V, 2200mAH. Any help would be greatly 
> appreciated in locating a substitute or original.

Mercury batteries are history as far as US sources are concerned. As I
understand it, some states enacted laws prohibiting their sale, and 
subsequently all of the manufacturers stopped making them here. There 
are a few types available still in Europe and Asia. This is particularly 
a problem for applications like magnetometers and light meters where 
the flat discharge characteristic is used to assure high stability. 
Mercury cells produce 1.35 volts for more than 90% of their life, 
while others drift with age. 

The practical substitute is a pack of alkaline or lithium cells driving 
a precision voltage regulator. Zinc-air cells work fairly well in
light meters at 1.4 volts but are not quite as stable, and produce 
a fraction of the current that mercury cells do -- 1 or 2.2 
amp-hours, no way.


-- 
David Josephson / Josephson Engineering / San Jose CA / david@.............

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From: frankcnd@.......... (Frank Condon)
Subject: Re: Need Source for mercury batteries
Date: Wed, 26 Aug 1998 01:58:20 -0700 (PDT)

Hi david:
I was afraid of that! How about if I install a DC/DC converter using a 4.0AH 
12VDC Gel Cell as the main power source? All I'd need to do is find one that 
has the correct current output rating and an adjustable regulated output.

Thanks,

Frank Condon
"Located in the seismic corridor somewhere between Fontana & Mammoth Lakes.
 
>> compensation Gamma and is a Mallory 6.75 V, 1000mAH. The other two are for 
>> portable power and use Mallory 6.75V, 2200mAH. Any help would be greatly 
>> appreciated in locating a substitute or original.
>
>Mercury batteries are history as far as US sources are concerned. As I
>understand it, some states enacted laws prohibiting their sale, and 
>subsequently all of the manufacturers stopped making them here. There 
>are a few types available still in Europe and Asia. This is particularly 
>a problem for applications like magnetometers and light meters where 
>the flat discharge characteristic is used to assure high stability. 
>Mercury cells produce 1.35 volts for more than 90% of their life, 
>while others drift with age. 
>
>The practical substitute is a pack of alkaline or lithium cells driving 
>a precision voltage regulator. Zinc-air cells work fairly well in
>light meters at 1.4 volts but are not quite as stable, and produce 
>a fraction of the current that mercury cells do -- 1 or 2.2 
>amp-hours, no way.
>
>
>-- 
>David Josephson / Josephson Engineering / San Jose CA / david@.............
>
>_____________________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email listserver@............. with the body of the 
>message: leave PSN-L
>
>


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From: David Josephson 
Subject: Re: Need Source for mercury batteries
Date: Wed, 26 Aug 1998 02:11:10 -0700 (PDT)

> I was afraid of that! How about if I install a DC/DC converter using a 4.0AH 
> 12VDC Gel Cell as the main power source? All I'd need to do is find one that 
> has the correct current output rating and an adjustable regulated output.

Yes, that will work, but I'll bet that the mag depends on very, very stable
6.75V  output. The fact that they use separate batteries for the compensation
coil and the main mag reinforces this. Even the best voltage references
have a drift on the order of 1 to 10 ppm per degree C. An ordinary good
regulator like Linear Tech LT1086 will probably work for portable power,
but I'll bet that you'll need something more stable for the compensation
coil. See the data sheets for Burr Brown REF-10 series, and Linear Tech
LT1236 etc.  

-- 
David Josephson / Josephson Engineering / San Jose CA / david@.............

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From: 
Subject: Re: Getting something-maybe microseisms
Date: Wed, 26 Aug 1998 11:29:49 EDT

Yes, microsiesms started here in northern Virginia on the E-W sensor about 6
PM yesterday and are quite strong this morning.  Nothing much on the N-S
sensor.  Likewise assume that Bonnie is the cause.

Bob Laney

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From: Karl Cunningham 
Subject: Re: Getting something-maybe microseisms
Date: Wed, 26 Aug 1998 09:11:02 -0700

Charlie --

You're not alone.  Background noise in Southern California is also up.  Had
to increase my alarm thresholds this morning.  Here, its usually from
tropical storms in the Eastern Pacific.

Karl Cunningham
La Mesa, CA.
PSN station #40
karlc@.......


At 02:29 AM 8/26/98 -0500, you wrote:
>All,
>
>Getting something 7:29 UTC, is it microseisms?  From Bonnie?


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From: S-T Morrissey 
Subject: hurricane microseisms
Date: Wed, 26 Aug 1998 16:53:34 -0500 (CDT)


Re: hurricanes and 6-second microseisms:

A historical note on tracking hurricanes before the use of
satellites and aircraft:  small seismograph arrays were used.
At our old station FLO outside St. Louis, two additional small
vaults were built 1/4 mile west and north of the main vault.
THen intermediate period (10 second) seismometers were used,
connected to 6-second galvanometers for photo recording with a 
peak response at 6-seconds.
THe relative phase of the microseisms crossing the L shaped
array  provided a vector pointing toward the origin if the waves.
It was much more accurate than 3-component particle motion
analysis. It also helps that the lithosphere under the eastern
USA is a fairly efficient waveguide for 6-second waves. They are
so monochromatic that we use passive twin-tee notch filters to 
reduce them by 1/100 for our high gain analogue monitor records.
They are recorded very nicely on the broadband instruments, so
I use also the notch filter here for the monitor recorder.

With several such stations (one was at Spring Hill, AL, another at
Rochester, NY) providing a pointer, the location of the hurricane
could be estimated, even when hundreds of km from shore.

Regards,
Sean-Thomas



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From: Karl Cunningham 
Subject: Re: hurricane microseisms
Date: Wed, 26 Aug 1998 15:21:39 -0700

Sean-Thomas --

Very interesting.  I wonder if such a system was ever tried on the west
coast.  As I understand, before the advent of satellites there was the
occasional hurricane that would hit San Diego or LA without warning.

Of course, nothing like the problems on the east coast.


Karl Cunningham
La Mesa, CA.
PSN station #40
karlc@.......


At 04:53 PM 8/26/98 -0500, you wrote:
>
>Re: hurricanes and 6-second microseisms:
>
>A historical note on tracking hurricanes before the use of
>satellites and aircraft:  small seismograph arrays were used.
>At our old station FLO outside St. Louis, two additional small
>vaults were built 1/4 mile west and north of the main vault.
>THen intermediate period (10 second) seismometers were used,
>connected to 6-second galvanometers for photo recording with a 
>peak response at 6-seconds.
>THe relative phase of the microseisms crossing the L shaped
>array  provided a vector pointing toward the origin if the waves.
>It was much more accurate than 3-component particle motion
>analysis. It also helps that the lithosphere under the eastern
>USA is a fairly efficient waveguide for 6-second waves. They are
>so monochromatic that we use passive twin-tee notch filters to 
>reduce them by 1/100 for our high gain analogue monitor records.
>They are recorded very nicely on the broadband instruments, so
>I use also the notch filter here for the monitor recorder.


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From: frankcnd@.......... (Frank Condon)
Subject: Re: Need Source for mercury batteries
Date: Wed, 26 Aug 1998 19:57:49 -0700 (PDT)

I assuming that the unit consumes 20mA at(+/-)6.75 VDC because the manual 
says that it will operate up to 100 hours on those 2200mAH batteries. Also, 
it says that the 6.75V field compensation circuit battery will need 
replacement after 500 hours and that one is rated for 1000mAH. So, it is 
only consuming a minimal 2.0mA
or so. Maybe I can use a small unregulated DC/DC converter and use a two 
stage zener regulator with two silicon diodes in series for temp 
compensation to replace it? Interestingly enough the manual says that the AC 
Supply which is inside of the unit is an option and appears to be a Full 
wave rectifier with a couple of zener diodes for its regulation. That should 
be easy to replace, just like you said! So, the tricky one to replace is the 
stand alone battery that is the reference. So, I hope the super regulator 
circuit will work satisfactorily.
other wise?

Frank...
"Located in the seismic corridor somewhere between Fontana & Mammoth Lakes"

>> I was afraid of that! How about if I install a DC/DC converter using a 4.0AH 
>> 12VDC Gel Cell as the main power source? All I'd need to do is find one that 
>> has the correct current output rating and an adjustable regulated output.
>
>Yes, that will work, but I'll bet that the mag depends on very, very stable
>6.75V  output. The fact that they use separate batteries for the compensation
>coil and the main mag reinforces this. Even the best voltage references
>have a drift on the order of 1 to 10 ppm per degree C. An ordinary good
>regulator like Linear Tech LT1086 will probably work for portable power,
>but I'll bet that you'll need something more stable for the compensation
>coil. See the data sheets for Burr Brown REF-10 series, and Linear Tech
>LT1236 etc.  
>
>-- 
>David Josephson / Josephson Engineering / San Jose CA / david@.............
>
>_____________________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email listserver@............. with the body of the 
>message: leave PSN-L
>
>


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From: David Josephson 
Subject: Re: Need Source for mercury batteries
Date: Wed, 26 Aug 1998 23:43:37 -0700 (PDT)

> or so. Maybe I can use a small unregulated DC/DC converter and use a two 
> stage zener regulator with two silicon diodes in series for temp 

I don't think this buys you nearly enough stability. I don't know what you
mean "DC/DC converter" unless you mean some sort of switching power supply,
and I would recommend against that because of the hash that would get in to
the front end of the mag. Just a regular linear regulator from a gel cell
would be fine.

> compensation to replace it? Interestingly enough the manual says that the AC 
> Supply which is inside of the unit is an option and appears to be a Full 
> wave rectifier with a couple of zener diodes for its regulation. That should 
> be easy to replace, just like you said! So, the tricky one to replace is the 
> stand alone battery that is the reference. So, I hope the super regulator 
> circuit will work satisfactorily.
> other wise?

Otherwise you work on it until it does work satisfactorily. Check the
rest of the field compensation circuit -- it's probably just a precision
regulated variable current source, in which case a new design of that,
which would compensate for variations in supply voltage, would do the trick.

-- 
David Josephson / Josephson Engineering / San Jose CA / david@.............

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From: Charlie Rond 
Subject: Re: Philosophic detour...
Date: Thu, 27 Aug 1998 05:36:19 -0500

Ken,

>I have been impressed by the selflessness of the people who have 
>"accepted the call" in the PSN group to take on responsibility with the 
>absence of any self motivated agenda!  This is truely an amazing group of 
>people and I am proud to be associated with all of you!
>
>
>...ramblings from Ken Navarre

That goes double for our regard for you, Ken!


 Charlie Rond     -\/\--Public Seismic Network-Memphis
                  http://gandlf.ceri.memphis.edu/~rond/psn        
  


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From: Jim Hannon 
Subject: Re: Need Source for mercury batteries
Date: Thu, 27 Aug 1998 06:03:18 -0500

There are temperature compensated zener diodes that should be just as
stable as the mercury battery.  One potential problem though is that the
stand alone battery may not have a common ground reference to the rest
of the circuit. If this is the case you would still need a separate
battery for the regulator. 
-- 
Jim Hannon
http://soli.inav.net/~jmhannon/
42,11.90N 91,39.26W
WB0TXL


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From: watson@................ (Charles Watson)
Subject: geomagnetic storm
Date: Thu, 27 Aug 1998 10:33:16 -0700

CNN is covering the geomagnetic storm from the solar flare a few days ago.

http://customnews.cnn.com/cnews/pna.show_story?p_art_id=2874045&p_section_name=Sci-Tech

-- 
---/----
cpw

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From: "Charles R. Patton" 
Subject: Re: Need Source for mercury batteries
Date: Thu, 27 Aug 1998 11:56:54 -0700

>So, the tricky one to replace is the 
> stand alone battery that is the reference. 

One other thought is that the magnetometer was depending on the low
noise characteristics of the mercury batteries.  Batteries can have much
lower noise than zener or band-gap references.  The effect is some 3
orders of magnitude or more from 0.1 Hz and up when compared with one of
the best lo-noise references, the LTZ1000A.   A good article with a
discussion and solution to this problem is:
Ultralow-Noise Programmable Voltage Source
IEEE Transactions on Instrumentation and Measurment, Vol 46, No. 6, Dec.
1997 Pg.. 1256-1260

Charles R. Patton

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From: Edward Cranswick 
Subject: PSN abstract for AGU
Date: Thu, 27 Aug 1998 17:21:15 -0600

PSN-
    Below is an abstract I plan to submit to the special session, "S12
Digital Communications in Seismology: Glimpses of the 21st Century Seen
Today?" of the December 1998 AGU meeting in San Francisco, and below
that is the session description. Please give me your thuoghts on this.
-Edward

***ABSTRACT***

Public Seismic Network (PSN): A Model for Science, Technology and
Community in the Coming Age

The Public Seismic Network (PSN) is a model for using technology to
connect human awareness to, rather than shield it from, the environment.
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. The World Wide Web is rapidly
engulfing nearly all aspects of human life and beginning to constitute a
virtual reality where many of us spend more and more of our time. At the
same time, the physical reality of Earth is being environmentally and
ecologically degraded at an ever-increasing rate.  A critical issue is
whether the Web will be used to enhance or to obscure our vision of
Earth. Most of the Web traffic contains very little sense data, i.e.,
empirical information, about the Earth. Other than the Internet and
other artificial electromagnetic media, seismic waves propagate more
rapidly and, therefore, convey information about the state of the planet
faster than any other means. Ground motions are disturbances of our rest
position on the Earth’s surface and convey the message that change in
life is ubiquitous and inevitable. Most of the energy of
earthquake-produced ground motions is in the frequency band, several
seconds to several Hertz, to which the human brain is most sensitive. If
we cannot respond to earthquakes, it will be even more difficult to
respond to other phenomena, such as global warming, with much longer
time constants. The distribution of low-cost broadband seismometers in
conjunction with Web access would allow people worldwide, i.e., the next
human generation of Earth, to directly perceive and to share the
concrete perception with each other that we all share the same ground.


***SESSION DESCRIPTION***

S12   Digital Communications in Seismology: Glimpses of the 21st Century
Seen Today?
The explosive growth in digital communications brought on by widespread
public interest in the internet has profoundly changed
seismic instrumentation. Digital communication links to seismic stations
for real-time data collection, near-real-time data
collection, or for least state of health data are becoming standard
experimental procedure. The rapid evolution of this
technology, however, has led to a proliferation of different approaches
to solving the same problem. The primary goal of this
session is to provide a forum for comparison of the different
technologies currently available. Our hope is that this will help
move the community toward a set of standards that will allow for a more
transparent exchange of data between networks and
for distribution to the broader community. In addition, widespread
availability of digital communication links to sensors and
between sensor networks promises to profoundly change the scientific
infrastructure of seismology. Papers are also solicited on
ideas for scientific problems that could be addressed by a network of
networks of seismic instruments on a national to global
scale with thousands of broadband seismic stations.

Conveners: Gary L. Pavlis, Department of Gelogical Sciences, Indiana
University, 1005 10 Street, Bloomington, IN 47405,
Phone: +1-812-855-5141, Fax: +1-812-855-7899, E-mail:
pavlis@............ and Steve Malone, Geophysics Program,
University of Washington, Box 351650, Seattle, WA 98195, Phone:
+1-206-685-3811, Fax: +1-206-543-0489, E-mail:
steve@......................


--
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".



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From: "Edward Cranswick" 
Subject: Re: Abstract for AGU Poster Session
Date: Thu, 27 Aug 1998 17:34:16 -0600

Ted-
    I am all set to sponsor your abstract, but I need a list of authors and
the phone, address and email of the contact author.  As soon as I hear from
you, I will submit it.
-Edward

-----Original Message-----
From: Ted Blank 
To: psn-l@............. 
Cc: cranswick@...................... 
Date: Monday, August 24, 1998 10:49 PM
Subject: Abstract for AGU Poster Session


>
>Edward,
>
>Here is what I have come up with for the abstract.  I was thinking that
>one teacher and 2 students could man the poster for shifts of (say) 2
>hours, then another couple of students could take over.  Usually there
>are just a handful of students in the class who get excited about
>operating the station, so between Almaden Country School and South Valley
>Junior High School maybe 10-12 students total would be chosen...
>
>Last year when I visited Larry and your poster session, I imagined that
>if we did a student session, the participants would get two benefits.
>First the experience of putting together the poster and display data from
>their own data.  Second, the opportunity to stroll around (chaperoned by
>teachers/parents) and see how the other scientists in the poster session
>have presented their work.
>
>I was imagining the poster itself in two parts.  One half would be based
>on what they have learned about the structure of the earth and the
>mechanisms which generate earthquakes.  The other half would be the
>results of their classroom monitoring - actual seismograms, P- and S-wave
>phase identifications, tied to a map of the earth showing the location of
>the quakes.
>
>Anyway, let me know what you think.
>-=-=-=-= Start of Abstract -=-=-=-=
>Seismic Monitoring in the Classroom-  A Complement to the Traditional
>Middle School Earth Science Curriculum
>
>For several years the Public Seismic Network (PSN) has supported several
>amateur seismic monitoring stations in Middle School science classrooms
>in the San Francisco Bay Area. Software, hardware and training are
>donated by the PSN.  Two of the longest-running stations are at Almaden
>Country School (6835  Trinidad Drive, San Jose 95120) and South Valley
>Junior High School of Science and Technology (385 I.O.O.F. Avenue, Gilroy
>95020) .
>Near the beginning of
>each school year a member of the PSN visits the school and provides the
>students and teachers with an overview of the station hardware and
>software.  During the remainder of the school year the students and
>teachers operate the station in conjunction with the earth science
>curriculum at the school.  Significant local and teleseismic events which
>pass the software triggering filter are analyzed and  P- and S-wave phase
>times are used to calculate the epicentral distance.  Results are checked
>for accuracy against USGS data from the World Wide Web.  Quake locations
>are tracked on small- and large-scale maps and students are encouraged to
>keep accurate station records.  Data collected at the school stations is
>uploaded to the PSN web site (http://psn.quake.net) and data from other
>PSN stations around the world is downloaded to provide the students with
>enough records to perform accurate triangulation of epicentral locations
>for large events.  Operation of a classroom PSN station provides students
>with the opportunity to participate in an unusual and direct hands-on
>Earth Science activity which, it is hoped, gives them a more solid
>foundation on which to anchor the information they will be receiving
>during the course of the year as they study the structure of the earth.
>Students also learn the frustrations associated with "real science" - the
>importance of accurate record keeping, lost/missing/poor quality data,
>hardware and software problems, etc.  This poster session will be manned
>by students and teachers from both schools who have participated in the
>operation of the classroom station during the course of the school year.
>It will consist of a review of the seismic data collected in the
>classroom and student interpretations of how that data fits in with
>current models of the structure of the earth.
>
>-=-=-=-= End of abstract -=-=-=-=-=
>
>Ted Blank
>San Jose, California
>
>
>_____________________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email listserver@............. with the body of the
>message: leave PSN-L
>
>



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From: frankcnd@.......... (Frank Condon)
Subject: Re: Need Source for mercury batteries
Date: Thu, 27 Aug 1998 17:27:29 -0700 (PDT)

That does create quite a predicament! The chassis has a front panel polarity 
switch that reverses the battery connections to the compensation coil. Looks 
like I will need a floating regulated 6.75 VDC power source to do the 
substitution.
Another small 1000mAH 12VDC gel cell should be able to provide the input 
power for the regulator circuit. 

Frank Condon
"Located in the seismic corridor somewhere between Fontana & Mammoth Lakes"

>There are temperature compensated zener diodes that should be just as
>stable as the mercury battery.  One potential problem though is that the
>stand alone battery may not have a common ground reference to the rest
>of the circuit. If this is the case you would still need a separate
>battery for the regulator. 
>-- 
>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
>
>


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From: Roger Griggs 
Subject: Cleaning out the junk box
Date: Thu, 27 Aug 1998 20:31:42 -0700

Hi all,

Karl has motivated me to check my salvage box and offer some electronics
that could be used in seismic applications.

I have about 16 ARNET serial boards. ARNET was bought out by Digi Board.
They are AT type boards that are ISA bus compatable. They were used in a
DOS box in a data aquisition system. There is an onboard processor but I do
not know its capacity or power. These are the Smartport 8 cards that have 8
channels that support buad rates upto 38.4 k all channels at the same time.
I think they cost about $1200 apiece about 5 years ago. About half of the
boards have RJ11 sockets right on the card and the other half, which are
newer, have a 50 pin DB socket. 8 RJ45 sockets are on the end of a 6' cable
that plugs into the socket. They are all in mint condition and working.
Some have never been used. I have one driver manual and one installation
manual so I would have to make copies.
I will happy to give these away to anyone on the PSN who can give me a good
line on why they want one and not just to add
more junk to the junk box. Hopefully it will be a project that has seismic
connections. Otherwise into the salvage bin they go.
Obviously you will want to pay for shipping and repo costs for the manuals.
I think these boards are going to need some programming nerds and not
someone who is faint at heart when they look into the guts of a pc.

In fact as I look deeper into the old junk box I see lots of boards (most
with manuals) for older pc's like AST Rampage memory boards, EGA video
cards, MFM hard drive controllers, 1200 buad modems, serial/parallel I/O,
and AST Fast ram memory boards (fully populated with 2 meg of ram, wow).
All for the price of a e-mail and shipping. So please e-mail me directly
and not to the list if any of this stuff has been on your "been trying to
find forever list". 
Lets get those essays in kids...

Roger
Oakley Seismic Station
Oakley, Calif. USA


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From: Steve Hammond 
Subject: Re: Update PSN San Jose Web Site
Date: Fri, 28 Aug 1998 21:41:12 -0700

Bob, I just found I never made this change..
 
 http://pw2.netcom.com/~shammon1/psncon.htm
 
 Anybody got an update I can add to the outreach list?
 Regards, Steve Hammond
 
> Bob Hammond (USGS-AVO Geophysicist) -created a k-12 science and math
> education project based on in-school seismographs in urban and rural
> Alaska.  Four schools are currently involved.

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From: Edward Cranswick 
Subject: [Fwd: ]
Date: Sat, 29 Aug 1998 22:49:21 -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".

Ken-
    Your name is familiar. I was at Lamont 1974-1978 but I returned
intermittently to give talks there, etc., at various times in the 1980s.
The Public Seismic Network (PSN) http://psn.quake.net/ is the best general
source of info about building seismographs, and Sean-Thomas Morrissey
http://www.eas.slu.edu/People/STMorrissey/index.html has built a
seismometer using a putty knife. Good luck!
-Edward

Kenneth J. Hurst wrote:

> Ed-
> I dont know if you know me, I believe I remember you from Lamont.
> I was there from 80-85 and again 88-90.
>
> I have volunteered to help out with the local Frazier Mountain High
> School physics class here. One project we were thinking of would be to
> build a seismometer. I seem to remember that you had a design for
> an instrument made from a putty knife and other odd things.
> Is my memory serving me correctly? Do you have any other ideas
> we might use?
>
> Thanks
>
> Ken Hurst
> Mail Stop 238-600                       voice: 818-354-6637
> Jet Propulsion Lab / Caltech            FAX:   818-393-4965
> Pasadena, CA 91109                      hurst@..................



--
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: meredith lamb 
Subject: Geophones (again) & Zap stuff
Date: Sat, 29 Aug 1998 23:39:18 -0600

Electronic Goldmine has reduced their price on the Geosource
Model MD-100, from $8.95 to $6.95.  Valid only through
September.  Their catalog #G9621.  Shipping and handling is
a minimum of $5.00.  P.O. Box 5408 Scottsdale, Az 85261
http://www.goldmine-elec.com

According to Steve Hammonds msg of 7/6/98, they are 14hz,
335 ohm and may be used (not new).

Frustration bit:  started to swap out Hall circuit for a improved
circuit, and about 3-4 minutes into this, the P wave from the
Marianas (mag 6.2) started coming in.......bad time....of course.
Ha.

Meredith Lamb


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: RLLaney@.......
Subject: PSN abstract for AGU
Date: Mon, 31 Aug 1998 13:31:05 EDT

Edward:

I was please to see the interest in bringing the Public Seismic Network to the
attention to the scientific community at the AGU meeting in December.  I
appreciate your taking the time to draft an abstract on this subject for the
meeting.

I have taken you up on your request for thoughts on the abstract for AGU.
Basically, I compared the abstract with the goals of AGU's Session 12,
"Digital Communications in Seismology:  Glimpses of the 21st Century Seen
Today?"  The session description is repeated below.  I read the session's
goals as follows (somewhat paraphrased):

1)  To provide a forum for comparison of the different technologies currently
available;

2)  To urge development of a set of standards that will allow for more
efficient exchange of data; and

3)  To  discuss ideas for scientific problems that could be addressed by
national and global and networks.

The abstract is repeated below.   The parts that are italicized and bold could
be kept much as they are because they address the goals of the session,
although additional words, no doubt, could always be added.  The middle part
of the abstract, which is underlined, has a number of references to
seismology-related issues, but this part seems somewhat philosophical in
nature and may not be directly focused on the objectives of the session.
Please see my suggestions below.



Subj:	 PSN abstract for AGU
Date:	98-08-27 19:22:31 EDT
From:	cranswick@...................... (Edward Cranswick)
Reply-to:	psn-l@............. (PSN-L Mailing List)
To:	psn-l@............. (PSN-L Mailing List)

PSN-
    Below is an abstract I plan to submit to the special session, "S12
Digital Communications in Seismology: Glimpses of the 21st Century Seen
Today?" of the December 1998 AGU meeting in San Francisco, and below
that is the session description. Please give me your thuoghts on this.
-Edward

***ABSTRACT***

Public Seismic Network (PSN): A Model for Science, Technology and
Community in the Coming Age

The Public Seismic Network (PSN) is a model for using technology to
connect human awareness to, rather than shield it from, the environment.
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. 

This is a good description of the PSN and it addresses the first goal of the
session.


The World Wide Web is rapidly
engulfing nearly all aspects of human life and beginning to constitute a
virtual reality where many of us spend more and more of our time. At the
same time, the physical reality of Earth is being environmentally and
ecologically degraded at an ever-increasing rate.  A critical issue is
whether the Web will be used to enhance or to obscure our vision of
Earth. Most of the Web traffic contains very little sense data, i.e.,
empirical information, about the Earth. Other than the Internet and
other artificial electromagnetic media, seismic waves propagate more
rapidly and, therefore, convey information about the state of the planet
faster than any other means. Ground motions are disturbances of our rest
position on the Earth’s surface and convey the message that change in
life is ubiquitous and inevitable. Most of the energy of
earthquake-produced ground motions is in the frequency band, several
seconds to several Hertz, to which the human brain is most sensitive. If
we cannot respond to earthquakes, it will be even more difficult to
respond to other phenomena, such as global warming, with much longer
time constants. 

I suggest altering this part of the abstract to tell what PSN can do right
now.  This would address the session goal number 2 of considering a set of
standards.  For example:

1)  Mention the type of seismic data PSN can collect and manipulate with SDR
and WinQuake (and EMON).

2)  Mention that we can interchange event files with Princeton Earth Physics
Project and binary SAC files.

3)  Perhaps mention the work that some have done with high schools?


The distribution of low-cost broadband seismometers in
conjunction with Web access would allow people worldwide, i.e., the next
human generation of Earth, to directly perceive and to share the
concrete perception with each other that we all share the same ground.

This part of the abstract begins to address the third goal of the session, but
it would be helpful if more specific types of scientific issues be mentioned;
for example, perhaps  suggest more work with high schools, museums, and county
and state parks that have visitor centers, etc. where seismographs and
computers connected to other networks could be set up to expose the general
public to the wonderful world of seismology, and more important a chance to
provide awareness and knowledge of the earth and its processes?  No doubt
there are many other scientific issues that could be mentioned.

I hope that others in the PSN list server will have additional thoughts and
suggestions.

Bob Laney



***SESSION DESCRIPTION***

S12   Digital Communications in Seismology: Glimpses of the 21st Century
Seen Today?
The explosive growth in digital communications brought on by widespread
public interest in the internet has profoundly changed
seismic instrumentation. Digital communication links to seismic stations
for real-time data collection, near-real-time data
collection, or for least state of health data are becoming standard
experimental procedure. The rapid evolution of this
technology, however, has led to a proliferation of different approaches
to solving the same problem. The primary goal of this
session is to provide a forum for comparison of the different
technologies currently available. Our hope is that this will help
move the community toward a set of standards that will allow for a more
transparent exchange of data between networks and
for distribution to the broader community. In addition, widespread
availability of digital communication links to sensors and
between sensor networks promises to profoundly change the scientific
infrastructure of seismology. Papers are also solicited on
ideas for scientific problems that could be addressed by a network of
networks of seismic instruments on a national to global
scale with thousands of broadband seismic stations.

Conveners: Gary L. Pavlis, Department of Gelogical Sciences, Indiana
University, 1005 10 Street, Bloomington, IN 47405,
Phone: +1-812-855-5141, Fax: +1-812-855-7899, E-mail:
pavlis@............ and Steve Malone, Geophysics Program,
University of Washington, Box 351650, Seattle, WA 98195, Phone:
+1-206-685-3811, Fax: +1-206-543-0489, E-mail:
steve@......................

_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: Edward Cranswick 
Subject: Re: PSN abstract for AGU
Date: Mon, 31 Aug 1998 12:58:46 -0600

Bob-
    Thank you very much for your feedback. I received quite alot of flack this
morning from an in-house USGS reviewer who shared some of your criticisms of the
overly philosophical aspect of the abstract. On the other hand, I have had a
couple of favourable comments made as well. So I am sure I will make some changes,
but I don't know about the extent of them yet.
-Edward

RLLaney@....... wrote:

> Edward:
>
> I was please to see the interest in bringing the Public Seismic Network to the
> attention to the scientific community at the AGU meeting in December.  I
> appreciate your taking the time to draft an abstract on this subject for the
> meeting.
>
> I have taken you up on your request for thoughts on the abstract for AGU.
> Basically, I compared the abstract with the goals of AGU's Session 12,
> "Digital Communications in Seismology:  Glimpses of the 21st Century Seen
> Today?"  The session description is repeated below.  I read the session's
> goals as follows (somewhat paraphrased):
>
> 1)  To provide a forum for comparison of the different technologies currently
> available;
>
> 2)  To urge development of a set of standards that will allow for more
> efficient exchange of data; and
>
> 3)  To  discuss ideas for scientific problems that could be addressed by
> national and global and networks.
>
> The abstract is repeated below.   The parts that are italicized and bold could
> be kept much as they are because they address the goals of the session,
> although additional words, no doubt, could always be added.  The middle part
> of the abstract, which is underlined, has a number of references to
> seismology-related issues, but this part seems somewhat philosophical in
> nature and may not be directly focused on the objectives of the session.
> Please see my suggestions below.
>
> Subj:    PSN abstract for AGU
> Date:   98-08-27 19:22:31 EDT
> From:   cranswick@...................... (Edward Cranswick)
> Reply-to:       psn-l@............. (PSN-L Mailing List)
> To:     psn-l@............. (PSN-L Mailing List)
>
> PSN-
>     Below is an abstract I plan to submit to the special session, "S12
> Digital Communications in Seismology: Glimpses of the 21st Century Seen
> Today?" of the December 1998 AGU meeting in San Francisco, and below
> that is the session description. Please give me your thuoghts on this.
> -Edward
>
> ***ABSTRACT***
>
> Public Seismic Network (PSN): A Model for Science, Technology and
> Community in the Coming Age
>
> The Public Seismic Network (PSN) is a model for using technology to
> connect human awareness to, rather than shield it from, the environment.
> 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.
>
> This is a good description of the PSN and it addresses the first goal of the
> session.
>
> The World Wide Web is rapidly
> engulfing nearly all aspects of human life and beginning to constitute a
> virtual reality where many of us spend more and more of our time. At the
> same time, the physical reality of Earth is being environmentally and
> ecologically degraded at an ever-increasing rate.  A critical issue is
> whether the Web will be used to enhance or to obscure our vision of
> Earth. Most of the Web traffic contains very little sense data, i.e.,
> empirical information, about the Earth. Other than the Internet and
> other artificial electromagnetic media, seismic waves propagate more
> rapidly and, therefore, convey information about the state of the planet
> faster than any other means. Ground motions are disturbances of our rest
> position on the Earth’s surface and convey the message that change in
> life is ubiquitous and inevitable. Most of the energy of
> earthquake-produced ground motions is in the frequency band, several
> seconds to several Hertz, to which the human brain is most sensitive. If
> we cannot respond to earthquakes, it will be even more difficult to
> respond to other phenomena, such as global warming, with much longer
> time constants.
>
> I suggest altering this part of the abstract to tell what PSN can do right
> now.  This would address the session goal number 2 of considering a set of
> standards.  For example:
>
> 1)  Mention the type of seismic data PSN can collect and manipulate with SDR
> and WinQuake (and EMON).
>
> 2)  Mention that we can interchange event files with Princeton Earth Physics
> Project and binary SAC files.
>
> 3)  Perhaps mention the work that some have done with high schools?
>
> The distribution of low-cost broadband seismometers in
> conjunction with Web access would allow people worldwide, i.e., the next
> human generation of Earth, to directly perceive and to share the
> concrete perception with each other that we all share the same ground.
>
> This part of the abstract begins to address the third goal of the session, but
> it would be helpful if more specific types of scientific issues be mentioned;
> for example, perhaps  suggest more work with high schools, museums, and county
> and state parks that have visitor centers, etc. where seismographs and
> computers connected to other networks could be set up to expose the general
> public to the wonderful world of seismology, and more important a chance to
> provide awareness and knowledge of the earth and its processes?  No doubt
> there are many other scientific issues that could be mentioned.
>
> I hope that others in the PSN list server will have additional thoughts and
> suggestions.
>
> Bob Laney
>
> ***SESSION DESCRIPTION***
>
> S12   Digital Communications in Seismology: Glimpses of the 21st Century
> Seen Today?
> The explosive growth in digital communications brought on by widespread
> public interest in the internet has profoundly changed
> seismic instrumentation. Digital communication links to seismic stations
> for real-time data collection, near-real-time data
> collection, or for least state of health data are becoming standard
> experimental procedure. The rapid evolution of this
> technology, however, has led to a proliferation of different approaches
> to solving the same problem. The primary goal of this
> session is to provide a forum for comparison of the different
> technologies currently available. Our hope is that this will help
> move the community toward a set of standards that will allow for a more
> transparent exchange of data between networks and
> for distribution to the broader community. In addition, widespread
> availability of digital communication links to sensors and
> between sensor networks promises to profoundly change the scientific
> infrastructure of seismology. Papers are also solicited on
> ideas for scientific problems that could be addressed by a network of
> networks of seismic instruments on a national to global
> scale with thousands of broadband seismic stations.
>
> Conveners: Gary L. Pavlis, Department of Gelogical Sciences, Indiana
> University, 1005 10 Street, Bloomington, IN 47405,
> Phone: +1-812-855-5141, Fax: +1-812-855-7899, E-mail:
> pavlis@............ and Steve Malone, Geophysics Program,
> University of Washington, Box 351650, Seattle, WA 98195, Phone:
> +1-206-685-3811, Fax: +1-206-543-0489, E-mail:
> steve@......................
>
> _____________________________________________________________________
>
> 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: curtis 
Subject: Re: Geophones (again) & Zap stuff
Date: Mon, 31 Aug 1998 12:01:04 -0700

Please, which catalog number are you using?  I could not find the
item number (#G9621) you mentioned.

tia,  curtis

meredith lamb wrote:
> 
> Electronic Goldmine has reduced their price on the Geosource
> Model MD-100, from $8.95 to $6.95.  Valid only through
> September.  Their catalog #G9621.

[snip]

_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: meredith lamb 
Subject: Additional S-G type seismo "Yellowstone" on line
Date: Mon, 31 Aug 1998 15:53:02 -0600

Hi all,

Just got done putting up my added S-G type East-West seismo
which uses a linear Hall sensor.  This, like the North-South,
has a gain of 500 (plus Hall 3X? amplification).  Built the same.
Luckily I can compare it too the Sprengnether East-West,
and a visual initial check, shows it too be fairly comparable.
Time and quakes will tell...

Bob Lamb has changed the circuit, and reduced the circuit
board noise roughly by 2/3rds, from the previous design. A
very good improvement in the reduction of spikes and occasional
oscillations experienced in the previous design.  Thanks Bob!

Have yet to go beyond a trash container plastic cover over it,
and a leaky styrofoam pier cover.  However, it seems to be
without much observable temperature change problems like the
other S-G.....   Likely, the size and weight (37lbs) construction
precludes much temperature sensitivity.

Thinking of calling it the "yellowstone", with its rough
volcano like structure, with a "dome" of plastic.  I figure
its different enough from the original S-G, to have a more
enticing name.....hmmmmmmm,...its cooking experimentally
anyway....

Bob Lamb quote: "Seismometrists are...sort of...OK"-ha.

Meredith Lamb


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: meredith lamb 
Subject: Re: Geophones (again) & Zap stuff
Date: Mon, 31 Aug 1998 16:18:38 -0600



curtis wrote:

> Please, which catalog number are you using?  I could not find the
> item number (#G9621) you mentioned.
>
> tia,  curtis
>
> meredith lamb wrote:
> >
> > Electronic Goldmine has reduced their price on the Geosource
> > Model MD-100, from $8.95 to $6.95.  Valid only through
> > September.  Their catalog #G9621.
>

The stock number is correct.  The number came from their
monthly flyer, which is separate from the main catalog, and being
as I bought some stuff awhile back, they do send it out to "buyers".
Its in the September 1998 flyer "catalog" titled "Hot Specials &
New Arrivals".  Perhaps a email or written request would produce
it?

Am not any  geophone authority, but previous msgs on PSN email,
talk of a variety of units, which may, or maynot, be of even
more interest and availability also.

Meredith Lamb






_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: Greg 
Subject: Re: Additional S-G type seismo "Yellowstone" on line
Date: Mon, 31 Aug 1998 15:36:26 -0700

meredith lamb wrote:

> Hi all,
> 
> Just got done putting up my added S-G type East-West seismo
> which uses a linear Hall sensor.  This, like the North-South,

Is there any chance of some internet accessible pictures, schematics or
drawings? Please.

,Greg

_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: meredith lamb 
Subject: "Cranking up" geophone output with additional magnets
Date: Mon, 31 Aug 1998 16:49:03 -0600

Hi All,

Being as the subject of geophones came up.  Have a question:
Would putting additional magnets on the outside case, be of
any value for increased sensitivity?  Suppose they might have
to be critically placed.  Did this yesterday with a Geosource
MD-81, 10hz, and it seemed to increase the sensitivity very
roughly... perhaps 20-40%.  Used a double pole neodymium
magnet flat on the case side.  Haven't tried regular 2 pole
magnets...yet....

Meredith Lamb


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: Art Kapoor 
Subject: Lehman Seismo Placement
Date: Mon, 31 Aug 1998 16:08:34 -0700

Hello Everyone,

I've got the electronics for my Lehman working and I am in the process
of putting the entire system together.  My only remaining challenge is
where to locate the seismo on my property.  I thought of locating it on
a concrete pad under my house in a insulated box as opposed to an
outdoor location.  The under house location saves effort in making the
whole thing weatherproof.  What I wish know is if any of you have any
experience with this type of location?  My concern is that this may
prove to be a noiser location than one outside in a remote corner of my
yard.  All of your thoughts and suggestions would be appreciated.

Regards to all,
Art Kapoor
Lafayette, CA

_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: barry lotz 
Subject: Re: Lehman Seismo Placement
Date: Mon, 31 Aug 1998 17:54:06 -0700

Art
   I have had my Lehman in a detached garage (about 40' away)for years.
It does pick up foot steps. If I lightly stomp on the floor I get
oscillations on the sensor. This is how I check if it's functioning
correctly(calibrated foot :). I imagine if your gain is high and the
frequency range includes 10 hz or so you may pick up footsteps in the
house. I'd try it anyway, experimenting is what it's all about. Good
luck! I hope to see some of your events posted in the future.BTW I've
spent a lot of time in the Lafayette,Concord area in the past. My folks
lived in Orinda.
                                    Regards,
                                    Barry
>Art Kapoor wrote:
> 
> Hello Everyone,
> 
> I've got the electronics for my Lehman working and I am in the process
> of putting the entire system together.  My only remaining challenge is
> where to locate the seismo on my property.  I thought of locating it on
> a concrete pad under my house in a insulated box as opposed to an
> outdoor location.  The under house location saves effort in making the
> whole thing weatherproof.  What I wish know is if any of you have any
> experience with this type of location?  My concern is that this may
> prove to be a noiser location than one outside in a remote corner of my
> yard.  All of your thoughts and suggestions would be appreciated.
>

_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: meredith lamb 
Subject: Re: Additional S-G type seismo "Yellowstone" on line
Date: Mon, 31 Aug 1998 19:06:01 -0600

Greg wrote:

> meredith lamb wrote:
>
> > Hi all,
> >
> > Just got done putting up my added S-G type East-West seismo
> > which uses a linear Hall sensor.  This, like the North-South,
>
> Is there any chance of some internet accessible pictures, schematics or
> drawings? Please.
>
> ,Greg
>

Greg,

Unfortunately its a no at this time.  I don't have a digital camera,
scanner, or even a diciperable schematic at this time and date.
Bob just changed the circuit yesterday and thus the circuit is not
up to date...it encompasses about 3 different circuits on one
original circuit drawing, with crossouts and etc.  About the only
plus is that I do have a web site, but....its empty at this time, and
limited too 2 megs....maybe inadequate unless things are moved
around from time to time.

In reality, my S-G type seismo, is a gross variation of the original
S-G, which uses a capacitive sensor and is ALOT smaller and
lighter in size.  My S-G is also made out of material that is not
obtainable for probably 100% of amateurs.  Nor is the type of seismo
really condoned in reality by any real professionals.  Being a non
professional, about all I can say for the seismo, is that it does
work very well from my limited viewpoint,...and mainly from a
comparison to my Sprengnethers output.   The only reason I'am
using the S-G, is because of other amateurs seem to get fair
results, and with the mass not subject too much tilt (except from
ground water cycles).  Am using eddy current damping with
aluminium plates with my S-G's, another weird approach, but
it works fairly well.  Perhaps, in the future, it might be possible
to use more common material than what I have....

Bob's circuit is deliously simple compared to most I've seen.  It
(for the moment) just uses a single dual op-amp; the National
LF412A, but even that can change soon enough.  The linear
Halls I've come to favor, seem to be the Allegro UGN7503, for
use with normal horizontals, and the 7515 for use with the 2
"Yellowstones" (ha), as they are much more sensitive, but have
a more limited field of displacement.  Without a doubt, the
biggest expense with the circuit, is having the dual polarity +
and - 12V power supplys, which for me, are adopted old
linear DC power supplys, not the switching type (which may
be useful?)

My goal for the time being, is the further observation of these
linear Hall units to prove that they are a viable means for purely
amateur use (at this time).  Have had them on 2 different seismos
and they do work, but the kicker is that one really needs a solid
stable pier and a well built seismo with very little mass drift, to
have them work well.  I  have one Hall on one of my horizontal
Sprengnethers, and it worked, but I only have 2 circuits for now,
so I'll leave them on the S-G's, till I stumble and accidentally can
replicate more-ha.  Basically....one seismo does not prove
anything, but 2 or preferably more, make it much more convincing.
Perhaps with time, I can install Halls on the other 2 Sprengnethers,
and with quakes records demonstrate their use.

So....at this time, I wouldn't recommend running out and buying
stuff, because everything could change in the next few months.
Now....I'am convinced...but that doesn't make for a good
recommendation without more backup, and a more proper
presentation.  I doubt that using Halls is new stuff, but I've seen
nothing within PSN.  For all I know, Sprengnether or some
other company is already selling Hall units...but I don't know.

Of any seismometer, I would recommend the Sean-Thomas
Morrissey STM-8, mainly because he is a professional and the
unit is a desireable vertical.  Horizontals are run of the mill stuff.
I use my Sprengnether vertical coil/magnet as the trigger for all
the rest, as it isn't so tilt sensitive of course.

Anyway.....thats the scope of it for now.  Sorry to disappoint
you at this time, but hopefully things will resolve in the future.

In the meantime, check out the ML1: Sprengnether coil/magnet
versus the ML4, and the ML3 versus the ML5 Hall records
"Hall-OH-grams", as they appear -ha.

Meredith Lamb


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: meredith lamb 
Subject: Re: Lehman Seismo Placement
Date: Mon, 31 Aug 1998 19:27:46 -0600

Art Kapoor,

Concede with Barry Lotz.  My 5 seismos are under the house,
and protected from undue moisture problems.  One will get
tilt from the house floor above, but that can be readily easily
recognized.  Suggest a 4" or thicker pier concrete base, 3'X3'.
You may want to review past PSN msgs, especially for Jan
1998, with alot of contributions from various people; they sure
went overboard and helped me with my similar question at the
time.  Talent galore in PSN.

Have fun.

Meredith Lamb





_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: Fred and Tina 
Subject: Geophone spec's
Date: Mon, 31 Aug 1998 20:49:50 -0700

Hi all,

Anyone have the spec's handy on the  Geosources Inc  Mod: MD-79

Thanks in advance
Fred

_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: Edward Cranswick 
Subject: USGS weak-motion seismograph deployment in the Santa Clara Valley
Date: Mon, 31 Aug 1998 22:11:17 -0600

PSN-
    Here is a .GIF-file
ftp://groundmotion.cr.usgs.gov/santaclara/sc_val_3.gif
of a map of the south Santa Clara Valley that displays the locations of
portable seismographs that have been deployed there since the early
summer by Al Lindh of the USGS.  I have also included some email
interchange with him on the subject.
-Edward

> Subject:
>         Re: Seismo-party in the Santa Clara Valley and the 13th fairie
>    Date:
>         Mon, 31 Aug 1998 13:29:43 -0700 (PDT)
>    From:
>         Al Lindh
>      To:
>         "Edward Cranswick, Lakewood, CO "
>
>
>
>
> 1.  We have the M5.4 Cienega event on about 95% of our stations
>       about 1/3 of the horz clipped slightly, those on soft sediments
>       and over the basin are of course the ones that clipped
> 2.  I will ship the data for JD224, which contains the event, to the DMC in
>       Seattle today or tomorrow, but with people in the field or on vacation
>          it will be sometime next week before they get it entered into the database
>
> 3.  It will be about a week before I get thru verifying that all the polarities
>        are correct.  then the data will be freely available
>
> 4.  Please do look at it asap, and encourage your PSN friends to do so also
>        If you could get their data for me in sac format, we would analyze
>         it along with ours, and acknowledge their contribution
>


> Subject:
>              Re: Seismo-party in the Santa Clara Valley and the 13th fairie
>         Date:
>              Mon, 31 Aug 1998 12:20:14 -0600
>        From:
>              Edward Cranswick
>  Organization:
>              US Geological Survey, Golden, CO
>          To:
>              Al Lindh
>   References:
>              1
>
>
>
>
> Al-
>     I finally got my act together and transferred some files from your
> FTP site (you know if it's not on the Web, I am too lazy to deal with
> it; but I finally did).  I see a beautiful map of the Santa Clara
> Valley, but I am a little unsure about what's what, though I assume the
> solid black squares are the locations of your stations. Is there a
> legend?
>     How did you make out with the M5.2 Holister event on 12 Aug? Larry
> Cochrane  of PSN recorded it on-scale with an
> FBA at his house in Redwood City. How does the data look in general? It
> is available somewhere to be scrutinized?
> -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: seismometer vault
Date: Tue, 1 Sep 1998 00:46:00 -0500 (CDT)

Art,

I support the idea that a basement or crawl space is adequate for
most seismology. OF COURSE a buried vault in a remote field would be
better, but this places lots of requirements on dryness, security,
temperature control (of both the vault and the seis), etc. not to
mention power for the amp, signal cables, critter control, etc. I 
have a nice hand dug 1 meter diameter pit 10 meters deep 800 feet from
the house in my back field, but it takes a weather-ready seis and 
system to use it (it does have a 1-sec telemetry unit in it for
noise comparison with a surface unit). I would LIKE to put an
STM vertical out there... some day.

Here is an edited version of previous pier info.
There are photos of this at:

http://www.eas.slu.edu/People/STMorrissey/index.html

The house here is also old, some of it log from 1917. The basement 
floor is thin concrete without rebar. The pier is in a former coal-bin
area.  The grout I used is the fine bagged prefab stuff designed 
for setting large floor tiles.
The concrete blocks of the pier are are solid, and set in a thick 
grout or mortar in a wood form on the floor, and also grouted together. 
Massiveness is the key here.  A tombstone would make a great pier. 
The top is made from two 24" x 24" patio pavers, and the 12" sq 
glazed ceramic tiles are grouted to the top of these. The glazed
surface allows thermal expansion of the seis base without the feet
sticking.

Re the enclosure box:
The draft-tight inner box is prefab shelving, because it is square 
and can be screwed together.  The front and lid are removeable, but 
restrained with brass latches and a thin foam weatherstrip for the top lid.
An important detail is that the three feet of the seis go through 1" holes
in the bottom of the inner box, so the seis sets on the glazed tiles
directly. Thin (1/4") foam sheet fitted around the feet, inside the box,
stop drafts. The box itself rests on a square of 1/4" weatherstrip
rather than directly on the pier surface, so the seis is the only
object making firm contact with the pier surface.

Regards,
Sean-Thomas

_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: John Hernlund 
Subject: Torsion and linear component station
Date: Tue, 01 Sep 1998 08:09:47 -0700 (MST)

Does anybody know or has anyone ever heard about any stations that have been
tried using the common three linear components (eg. Vn, Ve, and Vz) and also
three torsion components (eg. Ten, Tnz, Tez)?  The total output would be a
tensor which would also give rotational components...   

******************************************************************************

			       John Hernlund
     		          E-mail: hernlund@.......
      WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/
		    http://www.public.asu.edu/~hernlund/

"It is easier to excuse an ignorant person who claims that theory is
unnecessary and dispensable in his supposed practice, than to excuse a
Sophist who concedes its value to the schools (as, perhaps, only a mental
exercise) but who at the same time maintains that matters are quite
different in practice- that as one leaves school to enter the world, one
will realize one has been pursuing empty ideals and philosophical dreams-
and, in a word, that what sounds good in theory is of no practical
use."
-Immanuel Kant, On the Proverb: That May be True in Theory, But Is of No
Practical Use

******************************************************************************


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: Edward Cranswick 
Subject: Re: Torsion and linear component station
Date: Tue, 01 Sep 1998 12:13:33 -0600

John-
    In 1993, I recorded at magnitude 5+ earthquake at a station in San Bernadino,
CA, using a 3-component conventional (translational or linear) geophone and a
3-component Soviet-built rotational (torsional) seismometer.  There was a lot of
noise on the rotational sensor, after the SSA presentation I made, I was
distracted by the 1994 Northridge Earthquake, and I did not oursue the rotational
sensor further.
-Edward

***ABSTRACT***

RECORDINGS OF GROUND MOTION ROTATION IN SAN BERNARDINO, CALIFORNIA, PRODUCED BY A
MAGNITUDE 5 EARTHQUAKE

CRANSWICK, E., OVERTURF, D., BICE, T., US Geological Survey, MS 966, Box 25046,
Federal Center, Denver CO  80225, cranswick@...................  HOUGH, S., U.S.
Geological Survey, 525 Wilson Ave., Pasadena, CA  91106;  ABRAMOVICH, I., PMD
Scientific, Inc., 139A W.Dudleytown Rd., Bloomfield, CT  06002.

Sedimentary basins are often densely populated, and they are the sites of complex
interactions between seismic body waves and surface waves.  The shaking
experienced by manmade structures at such sites cannot be resolved into
translational modes only.  A novel seismic sensor was used to directly record the
rotational velocity components of ground motion at the Central Fire Station in San
Bernardino, California produced by a magnitude 5 earthquake at 95 km range (OT
1993 AUG 21 01: 46:38.39;  34 01.76' N, 116 19.26' W, z=9.04).  The
instrumentation had been  installed in a preliminary test configuration two hours
prior to the earthquake.  The rotational sensor recorded the angular velocities of
ground motion around three orthogonal axes (Z, N, E) in the frequency band
0.08-5.0 Hz. A collocated 2-Hz geophone recorded three orthogonal components of
translational ground velocity (Z, N, E).  All six channels were recorded at 100
sps/channel by a single digital recorder (GEOS).  The translational data were
corrected to extend their flat response to 0.1 Hz.  Low-frequency ground looping
and high-frequency coupling resonances of the rotational sensor create noise below
0.1 Hz and above 2 Hz respectively, but the signal is believed to be reliable in
the intervening frequency band.  Assuming SH wave propagation, the angular
rotation (integrated angular velocity) around the Z-axis estimates the SH shear
strain.  The ratio of the SH translational particle velocity to the shear velocity
of the medium independently estimates the SH shear-wave strain.  Phase velocities
inferred from these two strain estimates are in the range 0.1-1.0 km/s.  A strong
pulse of Z-axis rotation occurs at the time that a strong P-to-S converted phase
is observed on the radial component of translation.  This may be caused by
reflection or refraction from an interface that dips transversely to the the
radial direction.  The significant component of horizontal rotation associated
with the P-phase that is nominally characterized by radial motion only is an
example of the waveform complexity that must be considered in the design of
structures sensitive to torsional loads.

Cranswick, E., Overturf, D., Bice, T., Hough, S., Abramovich, I., 1994, Recordings
of ground motion rotation in San Bernardino, California, produced by a magnitude 5
earthquake: Seismological Research Letters, v. 65, no. 1, p. 39.


John Hernlund wrote:

> Does anybody know or has anyone ever heard about any stations that have been
> tried using the common three linear components (eg. Vn, Ve, and Vz) and also
> three torsion components (eg. Ten, Tnz, Tez)?  The total output would be a
> tensor which would also give rotational components...
>
> ******************************************************************************
>
>                                John Hernlund
>                           E-mail: hernlund@.......
>       WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/
>                     http://www.public.asu.edu/~hernlund/
>
> "It is easier to excuse an ignorant person who claims that theory is
> unnecessary and dispensable in his supposed practice, than to excuse a
> Sophist who concedes its value to the schools (as, perhaps, only a mental
> exercise) but who at the same time maintains that matters are quite
> different in practice- that as one leaves school to enter the world, one
> will realize one has been pursuing empty ideals and philosophical dreams-
> and, in a word, that what sounds good in theory is of no practical
> use."
> -Immanuel Kant, On the Proverb: That May be True in Theory, But Is of No
> Practical Use
>
> ******************************************************************************
>
> _____________________________________________________________________
>
> 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: change to abstract
Date: Tue, 01 Sep 1998 16:03:25 -0600

Steve Hammond-
    Congratulations on getting the PSN descriptions out to Steve Malone for the
IASPEI/CNSS inventory.
-Edward

Steve Malone wrote:

> Steve,
>         OK, I am back from vacation and catching up and have taken your
> last summary information and converted it to HTML and installed it in the
> summary page list.  You might check it out and see that it all looks OK.
>         http://www.cnss.org/NEWNETS/
>
> If you need to mkae other changes please grab this document as source,
> edit it with a text editor to make the changes and then e-mail me the
> source back so it will already be in HTML for me.
>         Thanks,
>
>         Steve Malone                    E-mail: steve@......................
>         Geophysics Program              Phone: (206) 685-3811
>         University of Washington        FAX: (206)543-0489
>         Box 351650                      Office: ATG-226
>         Seattle, WA 98195       http://www.geophys.washington.edu



--
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: Fw: Abstract for AGU Poster Session
Date: Tue, 1 Sep 1998 17:28:40 -0600

Catherine-
    In response to your email cited by John Taber, I am forwarding
this email to you to notify that Ted Blank & Jan Froom have submitted
this seismology-education related abstract (see below) to AGU today
for the December meeting.
-Edward

>Dear all,
>
>I have received several enquiries over the past few days from
>people who are interested in submitting seismology education
>related abstracts to the Fall AGU.  Please note that there
>are no special seismology sessions in education arranged for
>the Fall AGU.  AGU's current policy is to run Education sessions
>primarily at the Spring AGU.  However, I just talked with Steve
>Grand who is the program chair for the Fall AGU seismology
>program.  He is happy to accept education-related abstracts
>and if there are sufficient submitted he will make a dedicated
>session.  Unfortunately, unlike for the Spring AGU you are only
>allowed
>one first author contributed abstract (At Spring AGU two first
>author contributed abstracts were permitted as long as one was
>research-related and one education-related).  Remember, however
>that the first author need not be the presenting author so one
>can be creative in finding ways around this rule....
>
>I strongly encourage you to submit education-related abstracts
>if possible.  For those of you involved in research
>but also pursuing various education/outreach efforts,
>recognition
>of these education efforts by the same community that recognizes
>your research is extremely important.  If you do submit an
>abstract
>please send me the title, author list and text of your abstract
>by email - Steve Grand asked me to pass on a list of abstracts
>which I know to have been submitted to help him sorting through
>everything.  With some coordination we should be able to get at
>least one dedicated sessions.  Please pass this information
>along to
>any of your colleagues whom you think may be interested in
>submitting
>seismology education/outreach abstracts.
>
>Thanks!
>
>Catherine Johnson

-----Original Message-----
From: Ted Blank 
To: psn-l@............. 
Cc: cranswick@...................... 
Date: Monday, August 24, 1998 10:45 PM
Subject: Abstract for AGU Poster Session


>
>Edward,
>
>Here is what I have come up with for the abstract.  I was thinking that 
>one teacher and 2 students could man the poster for shifts of (say) 2 
>hours, then another couple of students could take over.  Usually there 
>are just a handful of students in the class who get excited about 
>operating the station, so between Almaden Country School and South Valley 
>Junior High School maybe 10-12 students total would be chosen...
>
>Last year when I visited Larry and your poster session, I imagined that 
>if we did a student session, the participants would get two benefits.  
>First the experience of putting together the poster and display data from 
>their own data.  Second, the opportunity to stroll around (chaperoned by 
>teachers/parents) and see how the other scientists in the poster session 
>have presented their work.
>
>I was imagining the poster itself in two parts.  One half would be based 
>on what they have learned about the structure of the earth and the 
>mechanisms which generate earthquakes.  The other half would be the 
>results of their classroom monitoring - actual seismograms, P- and S-wave 
>phase identifications, tied to a map of the earth showing the location of 
>the quakes.
>
>Anyway, let me know what you think.
>-=-=-=-= Start of Abstract -=-=-=-=
>Seismic Monitoring in the Classroom-  A Complement to the Traditional 
>Middle School Earth Science Curriculum
>
>For several years the Public Seismic Network (PSN) has supported several 
>amateur seismic monitoring stations in Middle School science classrooms 
>in the San Francisco Bay Area. Software, hardware and training are 
>donated by the PSN.  Two of the longest-running stations are at Almaden 
>Country School (6835  Trinidad Drive, San Jose 95120) and South Valley 
>Junior High School of Science and Technology (385 I.O.O.F. Avenue, Gilroy 
>95020) .
>Near the beginning of 
>each school year a member of the PSN visits the school and provides the 
>students and teachers with an overview of the station hardware and 
>software.  During the remainder of the school year the students and 
>teachers operate the station in conjunction with the earth science 
>curriculum at the school.  Significant local and teleseismic events which 
>pass the software triggering filter are analyzed and  P- and S-wave phase 
>times are used to calculate the epicentral distance.  Results are checked 
>for accuracy against USGS data from the World Wide Web.  Quake locations 
>are tracked on small- and large-scale maps and students are encouraged to 
>keep accurate station records.  Data collected at the school stations is 
>uploaded to the PSN web site (http://psn.quake.net) and data from other 
>PSN stations around the world is downloaded to provide the students with 
>enough records to perform accurate triangulation of epicentral locations 
>for large events.  Operation of a classroom PSN station provides students 
>with the opportunity to participate in an unusual and direct hands-on 
>Earth Science activity which, it is hoped, gives them a more solid 
>foundation on which to anchor the information they will be receiving 
>during the course of the year as they study the structure of the earth.  
>Students also learn the frustrations associated with "real science" - the 
>importance of accurate record keeping, lost/missing/poor quality data, 
>hardware and software problems, etc.  This poster session will be manned 
>by students and teachers from both schools who have participated in the 
>operation of the classroom station during the course of the school year.  
>It will consist of a review of the seismic data collected in the 
>classroom and student interpretations of how that data fits in with 
>current models of the structure of the earth.
> 
>-=-=-=-= End of abstract -=-=-=-=-=
>
>Ted Blank
>San Jose, California
>
>
>



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Public Seismic Network Mailing List (PSN-L)


From: Pinpoint 
Subject: Re: Fw: Abstract for AGU Poster Session
Date: Tue, 01 Sep 1998 16:43:40 -0700

At 05:28 PM 9/1/98 -0600, Edward Cranswick wrote:
<...125 lines snipped by a guy with only an AA in music!....>
,said .."methinks thou quote well...but yet exceedingly!"...:->
Bob
PINPOINT


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: "David A. Nelson" 
Subject: BIG QUAKE
Date: Wed, 02 Sep 1998 21:34:26 +1200


  Large Western Pacific quake in progress

  event arrival in dunedin NZ    08:40 UTC  wed 02 Sept. 98


  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: "Francesco" 
Subject: PHILIPPINE
Date: Wed, 2 Sep 1998 12:39:50 +0200

A LARGE QUAKE  AT 08.38  020998=20

MS 6.6
LOC:  MINDANAO-PHILIPPINE ISLANDS

Registered by all italian stations.

I.E.S.N.  -  PSN ITALY
Francesco Nucera









A LARGE QUAKE  AT 08.38  =
020998=20



 


MS 6.6


LOC:  MINDANAO-PHILIPPINE=20
ISLANDS


 


Registered by all italian =
stations.


 


I.E.S.N.  -  PSN =
ITALY


Francesco =
Nucera


From: Edward Cranswick 
Subject: Re: 6.7 Philippine files from Meredith Lamb
Date: Thu, 03 Sep 1998 02:17:59 -0600

Meredith-
    The times look pretty similar to me. Check out:
        ftp://groundmotion.cr.usgs.gov/PSN/lamb/980902/HOR0855R.GIF
-Edward

meredith lamb wrote:

> Hall stuff.  Can't make Hall & coil/magnet times agree.
> Shadow zone or ?
> Compare ML1 (15s coil) with ML4 (Hall 1s)
> Compare ML3 (15s coil) with ML5 (Hall 1s)
>
>   ------------------------------------------------------------------------
>
>                      Name: 980902a.ml4
>    980902a.ml4       Type: unspecified type (application/octet-stream)
>                  Encoding: base64
>
>                      Name: 980902a.ml5
>    980902a.ml5       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: John Hernlund 
Subject: Re: 6.7 Philippine files from Meredith Lamb
Date: Thu, 03 Sep 1998 08:31:50 -0700 (MST)

On Thu, 3 Sep 1998, Edward Cranswick wrote:
>     The times look pretty similar to me. Check out:
>         ftp://groundmotion.cr.usgs.gov/PSN/lamb/980902/HOR0855R.GIF

   They look pretty nice!  One thing to remember though is that a Hall sensor
gives an output voltage which is proportional to displacement, while the coil
gives an output which is proportional to velocity.  Therefore, you have to
integrate the coil signal, or differentiate the Hall response to get matched
units for a dependent variable...  Make sense?  Edward, did you differentiate
the Hall signal?

> > Hall stuff.  Can't make Hall & coil/magnet times agree.
> > Shadow zone or ?
> > Compare ML1 (15s coil) with ML4 (Hall 1s)
> > Compare ML3 (15s coil) with ML5 (Hall 1s)

******************************************************************************

			       John Hernlund
     		          E-mail: hernlund@.......
      WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/
		    http://www.public.asu.edu/~hernlund/

"It is easier to excuse an ignorant person who claims that theory is
unnecessary and dispensable in his supposed practice, than to excuse a
Sophist who concedes its value to the schools (as, perhaps, only a mental
exercise) but who at the same time maintains that matters are quite
different in practice- that as one leaves school to enter the world, one
will realize one has been pursuing empty ideals and philosophical dreams-
and, in a word, that what sounds good in theory is of no practical
use."
-Immanuel Kant, On the Proverb: That May be True in Theory, But Is of No
Practical Use

******************************************************************************


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: Nick & Sophie Caporossi 
Subject: Pivot point
Date: Thu, 03 Sep 1998 19:08:57 -0400

To Psn members:
 Am one of the Silent members.
 I am having some trouble with the pivot point on a horizontal seismograph.
The Boom it a steel rod. The end is grounded to a point and sit in a small
tapered hole in a steel bolt. Am using picture frame wire to hold up the
boom and a fishing swivel Eyelet to fasten to the vertical up right. I have
the boom at about 38 deg. from the horizontal. The center of the mass of
the boom is about 30 inches. I am using oil as a damper. The magnet and
pick up coil seem to be working ok. It operates very well for a few weeks.
It then does not osculate correctly. It will not come back to dead center
as it first was balanced. I currently have the system on a heavy duty work
bench.  This will not be it's permanent spot.
Any suggestions or help would be appreciated.

 Nick Caporossi, nickcap@.............

_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: "J. D. Cooley" 
Subject: Iris.Washington.edu question
Date: Thu, 03 Sep 1998 19:24:58 -0700

I don't see any place to ask questions on the washington.edu site, so I will 
ask here.

When I ftp to dmc.iris.washington.edu/pub/farm etc. and I look at the
seismograms
I see numbers next to the station identifications.  What do they mean?

example:

9/3/98 17:37

CPUP 13 80 P+
LPAZ 13 14 P+
NNA 18343 P+

Thanks in advance,

"JD"


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: Steve Hammond 
Subject: Re: Pivot point
Date: Thu, 03 Sep 1998 20:37:47 -0700

Hi Nick-- The level of the workbench has changed. Most likely due to the
ground under the floor drying out or becoming wet. In what area are you
located? You should find that it does not take too much change to
recenter the boom. If you look at
http://pw2.netcom.com/~shammon1/equip.htm 
you will see that even though the unit is clamped to the workbench with
a C-clamp, there are 2 (you can only see 1) screws at the left and right
rear of the base plate in the photo. I use these screws to re-center the
boom when it drifts. 
Regards, Steve Hammond  PSN San Jose


Nick & Sophie Caporossi wrote:
> 
> To Psn members:
>  Am one of the Silent members.
>  I am having some trouble with the pivot point on a horizontal seismograph.
> The Boom it a steel rod. The end is grounded to a point and sit in a small
> tapered hole in a steel bolt. Am using picture frame wire to hold up the
> boom and a fishing swivel Eyelet to fasten to the vertical up right. I have
> the boom at about 38 deg. from the horizontal. The center of the mass of
> the boom is about 30 inches. I am using oil as a damper. The magnet and
> pick up coil seem to be working ok. It operates very well for a few weeks.
> It then does not osculate correctly. It will not come back to dead center
> as it first was balanced. I currently have the system on a heavy duty work
> bench.  This will not be it's permanent spot.
> Any suggestions or help would be appreciated.
> 
>  Nick Caporossi, nickcap@.............
> 
> _____________________________________________________________________
> 
> 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: meredith lamb 
Subject: Re: Pivot point
Date: Thu, 03 Sep 1998 23:27:43 -0600

Nick & Sophie Caporossi wrote:

> To Psn members:
>  Am one of the Silent members.
>  I am having some trouble with the pivot point on a horizontal seismograph.
> The Boom it a steel rod. The end is grounded to a point and sit in a small
> tapered hole in a steel bolt. Am using picture frame wire to hold up the
> boom and a fishing swivel Eyelet to fasten to the vertical up right. I have
> the boom at about 38 deg. from the horizontal. The center of the mass of
> the boom is about 30 inches. I am using oil as a damper. The magnet and
> pick up coil seem to be working ok. It operates very well for a few weeks.
> It then does not osculate correctly. It will not come back to dead center
> as it first was balanced. I currently have the system on a heavy duty work
> bench.  This will not be it's permanent spot.
> Any suggestions or help would be appreciated.
>
>  Nick Caporossi, nickcap@.............
>

Hello Nick,

Sounds too me like your work bench is tilting, sagging from your
instrument weight; or it could be other influences acting on the
work bench.  Possibly your base plate maybe also be slowly
deforming....does it have adjustment screws?  Presume you also
mean the angle is nearer to 90 degrees....then use your base
plate screws to increase/decrease the period.

I'd accelerate building your pier, hopefully in a protected
environment.  Do you have a crawl space, basement, garage,
for placement?  Preferably a form of concrete/blocks/stepping
stones cemented together, and perhaps 3' X 3' X ~ 4-6" thick.
I use a ground covering of plastic sheet, then stepping stones
cemented together, then a tile top.  I have also painted the
pier/s with a acyclic/latex called ConcoPro, which unlike most
paints seems to remain like a pliable plastic....to keep the
humidity/water out of the "pier" and affecting the seismo on top.
I used masonry cement between 3 layers of stepping stones,
and let it all dry out first, before, painting.  Takes time, but it is
not very costly.  I use a crawlspace myself, with bare ground.
Settling in time will vary with location, my clay environment
usually takes 2-3 weeks.

You also need an enclosure around the pier, mainly to keep
drafts from affecting your coil/magnet.  Likely because it is a
coil/magnet, temperature affects won't show up noticeably.
Allow room for yourself and the instrument adjustments.  Try
to allow extra for height; its no fun bending all the time, if
possible.

If you can download past PSN email messages, I'am sure you
will find alot of similar references to problems/solutions.  You
might also check out the web stations with pictures of similar
instruments, that can help alot.

I'd be interested in more detail of your horizontal...this would
likely give way to suggestions for assistance.  Heck....we all
have problems...

Have fun,

Meredith Lamb


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: "Ron Horton" 
Subject: Re: Pivot Point
Date: Fri, 4 Sep 1998 08:58:33 -0000

Hi all,

I just completed building Lehman sensor (thanks to help from John Cole & =
Frank Cooper) and have noticed that I have to adjust level periodically. =
I also have noticed that the longer the period the more often I have to =
adjust. My question is, why does the level change quicker with longer =
period ? Thanks in advance.

Have a great day !
Ron Horton









Hi all,


 


I just completed building Lehman =
sensor (thanks=20
to help from John Cole & Frank Cooper) and have noticed that I have =
to=20
adjust level periodically. I also have noticed that the longer the =
period the=20
more often I have to adjust. My question is, why does the level change =
quicker=20
with longer period ? Thanks in advance.


 


Have a great day !


Ron Horton


From: "James M Hannon" 
Subject: Re: Pivot Point
Date: Fri, 4 Sep 1998 09:25:06 -0500



Ron,
 At long periods the amount of movment required to mess things up is much
smaller than at shorter periods. So for the same amount of drift the
instrument will go out of adjustment sooner when adjusted for long periods.

Jim Hannon

Jim Hannon



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From: S-T Morrissey 
Subject: horizontal sensitivity
Date: Fri, 4 Sep 1998 11:03:55 -0500 (CDT)

Some thoughts on building the Lehman seismometer:

The Lehman is a "poor-boys'" version of the Columbia-Sprengnether
S5000 long-period, of which there are over 1000 in use.
I have scanned a pictorial drawing of it to my web site on
the psn info page. 

http://www.eas.slu.edu/People/STMorrissey/index.html

Of particular interest is the lower suspension of the boom.
Here the boom passes over the frame member attached to the base,
and pulls on the frame via a taught wire arrangement. For
the Lehman, I would make a right angle fixture at the end of
the boom, and have it drop down behind the place where the
bolt and pivot currently are, and pull from the "backside"
with a short ( about 1 cm ) length of music wire.  The operating
principal of this horizontal configuration assumes that forces
(torques) about the boom pivot are minimal, and the period is actually
controlled by the angle of the boom with respect to the horizontal.

Some formulae of interest for the horizontal pendulum:
(assuming that the restoring force by the hinges and/or 
pivot are minimal):

The natural period: Tn = 2*pi*sqrt(l/(g*sine i))
 
where l is the boom length in cm, g=980cm/sec^2, i is the angle
that the boom makes wrt the horizontal, measured in radians,
(where sine i = i). For example, a 40 cm boom hanging vertically
as a simple pendulum ( an angle of 90 degrees) has a period of 
1.3 seconds. (a one second clock pendulum is 24.8 cm). When tilted
horizontally to about 4 degrees, the period is 5 seconds. At
about a 1 degree angle, it is 10 seconds, and at about 0.23 deg.
it is 20 seconds. So the period is changing with inverse of the
square root of the angle, which is why long periods are so unstable.
But unstable also means sensitive to smaller ground motions.

So the stability question for a horizontal seismometer depends 
mostly on the mechanical period and the working range of the 
velocity coil; ie how far it can drift before touching. The 
old S5000s that I operate at 15 seconds in vaults rarely 
need to be recentered.  (the working range is +,- 5mm for 
these horizontals). Years ago we ran them at 30 seconds, 
and had to center them about every other month.  I understand 
that most Lehmans operate at 10 seconds give or take, 
but that some can be workable at 20 seconds with more 
frequent adjustment. Of course, the stability of the pier
becomes a major concern. Also, thermal effects on the base
and frame of the instrument can cause major drifting.

My specific hope for someone making a new Lehman would be to 
to make it as rugged and massive as possible so that longer
periods are easily attainable, (which provides a significantly more 
interesting response to teleseisms), but without the problem 
of needing frequent recentering. A 20 second instrument would be nice,
but would need 4 times the tilt stability of a 10 second sensor.
I don't have any information on the actual sensitivity of the 
Lehman designs that are in use. But for comparison to the S5000s 
I am operating at 15 seconds, which have a 32 tpi (turns per inch) 
leveling screw, about 1/100th turn (the leveling knob happens 
to have about a 100 mm circumference) is about 16 microradians, 
and moves the mass about 1mm.  One can calculate how much the 
mass should move when tilted at a given period.

Calculation of the tilt sensitivity of the horizontal pendulum:
(which can be used to calibrate the displacement detector)

			z = (g * Tn^2 / 4 * pi^2) * phi

where z is the horizontal displacement of the mass, Tn is the 
natural period, and phi is the tilt of the base at right angles
to the boom, again measured in radians. g = 980cm/sec^2; z = cm.

From my example above about the S5100: the base is 500 mm, so
the tilt from 1/100 turn of the screw ( which is 0.008 mm) is 
0.008/500 = 0.000016 radian. If Tn = 15 seconds, the mass will
move 0.89 mm, which is close to my approximation.

Evaluating this on my STM-8 horizontal, with l = 40 cm, and 
Tn = 10 seconds, 1/12 turn of the 28 tpi leveling screw is
0.9mm/12 = 0.075mm; the base width is 130mm, so the tilt is
0.075/130 = 0.00058 radians. This calculates to an offset
of the mass of 1.43 cm, which is about what I measure. At
20 seconds, the offset is about 4 times, or 5.7 cm. 

Two points are clear: the stability is inversely proportional
to the square of the period, or conversely, the sensitivity
increases with square of the period.  And the amount of the mass
is not a consideration for the period or the displacement
sensitivity.  As long as it is significantly greater (like 10x)
than the weight of the boom, it will work.

And a final thought: I would forgo the hydraulic damping and
simply use resistive damping with the main coil by shunting
it with an appropriate resistor, which is what is done in
modern seismology. The value of the resistor  can be readily 
calculated; the voltage loss of the resistive damping is easily
made up for with additional gain of the preamplifier.

regards,
Sean-Thomas


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From: Ted Blank 
Subject: Re: Pivot point
Date: Fri, 4 Sep 1998 10:03:00 -0700 (PDT)


Nick,

Grinding the end of the boom to a point will lead to other problems.  It 
will be very difficult to get the point and it's tapered recess hole to 
match correctly, and the point will eventually try to "walk" up the sides 
of the recess.  Even worse, the single point of contact allows the boom 
to rotate around its long axis, which will contaminate your recordings 
with spurious oscillations.

The original Lehman design called for grinding the end of the boom to a 
knife edge.  Very hard to do this and keep it in contact over the entire 
knife edge for very long.  I ended up grinding mine to a knife edge and 
then removing material in the middle of the knife edge.  Result was two 
tiny knife edges, one at the very top and one at the very bottom of the 
boom.  (Boom was 3/8" steel rod).  You can adjust this fairly easily to 
get both edges firmly touching the support and it would stay in 
adjustment for a long time.

However, I do think a better approach would be to design a support which 
operates in tension.


Ted Blank
San Jose, California

On Thu, 3 Sep 1998, Nick & Sophie Caporossi wrote:

> To Psn members:
>  Am one of the Silent members.
>  I am having some trouble with the pivot point on a horizontal seismograph.
> The Boom it a steel rod. The end is grounded to a point and sit in a small
> tapered hole in a steel bolt. Am using picture frame wire to hold up the
> boom and a fishing swivel Eyelet to fasten to the vertical up right. I have
> the boom at about 38 deg. from the horizontal. The center of the mass of
> the boom is about 30 inches. I am using oil as a damper. The magnet and
> pick up coil seem to be working ok. It operates very well for a few weeks.
> It then does not osculate correctly. It will not come back to dead center
> as it first was balanced. I currently have the system on a heavy duty work
> bench.  This will not be it's permanent spot.
> Any suggestions or help would be appreciated.
> 
>  Nick Caporossi, nickcap@.............
> 
> _____________________________________________________________________
> 
> Public Seismic Network Mailing List (PSN-L)
> 
> To leave this list email listserver@............. with the body of the 
> message: leave PSN-L
> 

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From: Karl Cunningham 
Subject: Re: Pivot point
Date: Fri, 04 Sep 1998 10:30:18 -0700

Nick --

Likely tilt is your main problem, as others have suggested.  But I have
also had problems with friction in the pivot causing hysteresis -- the
tendency for the boom to not come back to the same place after being
deflected.  If you think about what is going on at the pivot on a
microscopic scale, the point will actually have a very small blunt end and
irregularities and the hole in the bolt has irregularities too.  So on a
very small scale there might be some sliding and grinding of microscopic
metal particles which get in the way of a smooth pivot.  The instrument is
more sensitive to this with longer periods, for the same reasons as as tilt
is: the restoring force on the boom due to gravity is less for longer
period instruments.

For my seismo, a very small drop of automatic transmission fluid in the
pivot reduced the problem to where it wasn't a factor.

Karl Cunningham
La Mesa, CA.
PSN station #40
karlc@.......

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From: "Frank Cooper" 
Subject: Re: Pivot point
Date: Fri, 4 Sep 1998 15:05:39 -0500

Nick,
You might consider John Cole's solution for reducing friction at the pivit
point by using a ball bearing.  Pictures of this process are posted on my
web site at http://freeweb.pdq.net/fxc/
Frank Cooper, Friendswood, Texas, USA





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From: S-T Morrissey 
Subject: Re: "Cranking up" geophone output with additional magnets
Date: Fri, 4 Sep 1998 17:07:19 -0500 (CDT)

Meredith,
The geophone has a cylindrical magnet in the center, and a thick cylindrical
ferrous shunt around it, with the coil bobbin suspended in between. 
On small phones, the outer cylinder is the outer case; on others,
like the HS-1 4.5hz from geospace, there is an aluminum casing on
the outside. Since the magnetic polarity of the outer shunt cylinder 
is induced by the central magnet, adding additional magnets in parallel
with it might increase the net field strength of the assembly. Or it may
also depolarize the shunt and reduce the output. And unless the effect
was very symmetrical, it could cause non-linear output.

However, I doubt that that any major increase can be realized compared
with simply doubling the gain of the amplifier. The output of these
small geophones is already remarkedly high, like 40 V/m/sec for a 4.5 hz
phone with a 1250 ohm coil.

Regards,
Sean-Thomas


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From: johnccole@........ (john c cole)
Subject: Re: Pivot point
Date: Fri, 4 Sep 1998 19:26:11 -0500

gentlemen
  your comments  about the pivot point were correct. if you want an
instrument with a long time period , use a ball bearing on a hard
polished surface. i have two detectors running using the ball bearing as
a pivot point and they will give you any time length that you want . i
run mine at about 16 seconds. very little adjustments necessary. the
longer the time , the more adjustment. if you place the ball bearing in
an indention , you are back with the friction problem. try to make the
surface that the ball bearing rest on as hard as possible to prevent
pitting when the boom is accidently forced into the flat surface. 
  try this method and see for yourself . you can always change it back.
                                                             john cole

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From: S-T Morrissey 
Subject: Hall-effect sensors
Date: Fri, 4 Sep 1998 20:33:39 -0500 (CDT)

Meredith,

You and others are wondering why we don't see hall-effect  sensors 
used in commercial seismometers and force-balance accelerometers.
The simple answer is that because if the physics involved, the numbers 
don't look very good if one wants a low noise sensor. The manufacturers 
of modern (especially broadband) seismometers have the USGS low noise 
model framed on their walls, and among other criteria (such as power 
consumption), it is the holy grail of expected performance, since they 
know that the seismologists with the $$$$$ also have it on their wall, 
even though probably only 10% of the sites in the world are quiet enough 
to realize it. 

Even though hall-effect technology has greatly improved in recent years
(you might even have one in the solid-state distributor in your car),
I know of no manufacturer of seismic instruments that has successfully
employed a hall-effect device. Most hall devices are used as switches;
linear, proximity, or distance determining applications are limited.

Since most of seismology has been based on velocity data, moving-coil 
sensors have been preferred for low noise, high output, and ease of 
damping, with no power consumption. Displacement sensors are used 
in fedback instruments which are configured for a linear velocity output, 
Some use LVDT displacement sensors specifically designed for low noise.
Most utilize capacitive sensors working over a very small range,
(but in differential mode for linearity), with a resolution of less
than a nanometer. The noise level of the USGS new low noise model at 
1 hz is at a power spectral density of about -160 db (referred to 1 
meter/sec^4/hz), which is a displacement of 10^-8 meter, or 10 nano-,
meters. Manufacturers want good signal-to-noise figures here, so
detectors have to be much better, like 0.1 nanometer.

I have reviewed the details and specifications of some of the linear
sensors and the magnet configurations necessary for a linear gradient
of the magnetic field.  Two considerations are of prime concern: the
displacement equalavent of the sensor noise, and the dynamic range.

The dynamic range estimate is based on the advertised linear range
(of the Allegro device) of +,- 2 volts, with a  wideband noise (at 10 hz)
level of 0.4 millivolts, a ratio of 4 volts to 0.4 mv, which is 10 000 
to 1. This is only 80 db, or about 14 bits of resolution. The actual 
dynamics of earthquakes requires a range of at least 120 db.

The other consideration is the noise figures when referred to actual
displacement. Two figures are given: "quiescent output drift", a rather
undefined figure of temperature dependence, usually about 2mv/degC, which
is the temperature stability near "DC" frequencies, and "wideband noise", 
which is specified from 10hz and up.  This wideband noise will follow
the 1/f law, meaning that it is 10 times greater at 1hz than 10 hz, etc.

To convert these numbers into displacement the gradient of the 
magnetic field has to be known. The literature indicates
that 10 gauss per mil (0.001") is a practical figure, but that some magnet 
configurations, using rare earth alloys, can achieve 100 gauss/mil, 
which severely limits the linear range because the hall sensor starts
to saturate (go non-linear) at about 400 gauss. (a peak output of +,- 2000
millivolts at 5mv/gauss = +,- 400 gauss). At 100 gauss/mil, the range
is therefore +,- 4 mils or about 100 microns (0.1mm).

What is the useful range in a field of 10 gauss/mil? Using 1 mil = 25.4 
microns, and assuming a sensor output of 5 mv/gauss, a field gradient of 
10g/mil (or 10g/25.4u) is 50mv/mil or ~2mv/micron.  If the linear range is 
+,- 2 volts, 2mv/micron is +,- 1000 microns or +,- 1 mm.

So, what is the displacement equivalent of the noise?  The wideband noise
is given as 0.4 mv at 10 hz. But at 1 hz it will be 4 mv, and 10x more 
at 10 seconds (that pesky 1/f law). Considering the 1 hz level, 4 mv
in the 10 gauss/mil field is 2 microns (peak to peak). If the intense
100 gauss/mil gradient is used, the noise is still 0.2 microns, or
200 nanometers. Unfortunately, it would be 10x greater at 10 seconds.

So this is the reason that hall-effect sensors are not used in commercial
seismometers; there are also other complications, such as the need for
magnetic shielding for protection from Geomagnetic storms, and the problem
of the magnet strength varying inversely with temperature, etc. Also,
the DC offset or drift must be removed by differentiation to a velocity 
signal, or the displacement signal must be used in a feedback configuration. 

But I think that these noise figures would be an impediment to using 
hall-effect sensors in  high resolution amateur seismic sensors, (although 
their performance might be better than some of the sensors that are in use). 
Considering the data from the VBB operating in the basement here; it 
has a velocity output of 3.2mv/micron/second.
So the displacement sensitivity at 1 second is 2*pi*3.2 or 20mv/micron. 
The quietest nighttime earth background noise is 0.4 to 0.8 mv, or 0.02
to 0.04 microns, or 20 to 40 nanometers, (at 1 hz).  I think that every
seismologist should be able to record the quietest signal possible, as
limited by location or siting, and not by the sensor or electronics.

regards,
Sean-Thomas

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From: johnccole@........ (john c cole)
Subject: Re: Pivot point
Date: Fri, 4 Sep 1998 20:33:40 -0500

karl
 your reply to nick was fantastic. most of us do not think of the problem
 in a microscopic way. it took two or three weeks for me to find out why
i could not get a longer time. when i changed to the ball bearing point
on the polished surface , the time went up dramatically. i can now choose
a practical  time. drill a hole in the end of the boom and glue a ball
bearing in the hole. the ball bearing should rest on a flat polished hard
bolt head etc.
                                                           john  w5auh

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From: Ted Blank 
Subject: Re: Pivot point
Date: Fri, 4 Sep 1998 20:51:13 -0700 (PDT)

John,
I can certainly appreciate the benefit of the ball bearing approach and I 
will use it if I ever build another Lehman.  However, don't you find 
unwanted oscillation around the long axis of the boom?  Most of the booms 
I've constructed have a fairly hefty piece of copper attached to one end 
which hangs down into the magnetic field of the damping magnets.  This 
weight acts like a pendulum and is very easy to set swinging.  Would 
using two ball bearings a cm or so apart be workable?  Keeping them both 
in contact with the polished surface might be problematic though.  


Ted Blank
San Jose, California

On Fri, 4 Sep 1998, john c cole wrote:

> gentlemen
>   your comments  about the pivot point were correct. if you want an
> instrument with a long time period , use a ball bearing on a hard
> polished surface. i have two detectors running using the ball bearing as
> a pivot point and they will give you any time length that you want . i
> run mine at about 16 seconds. very little adjustments necessary. the
> longer the time , the more adjustment. if you place the ball bearing in
> an indention , you are back with the friction problem. try to make the
> surface that the ball bearing rest on as hard as possible to prevent
> pitting when the boom is accidently forced into the flat surface. 
>   try this method and see for yourself . you can always change it back.
>                                                              john cole
> 
> _____________________________________________________________________
> You don't need to buy Internet access to use free Internet e-mail.
> Get completely free e-mail from Juno at http://www.juno.com
> Or call Juno at (800) 654-JUNO [654-5866]
> 
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> 
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> 
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> message: leave PSN-L
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From: "Frank Cooper" 
Subject: PIVOT POINT
Date: Fri, 4 Sep 1998 23:55:17 -0500

Please see my web site http://freeweb.pdq.net/fxc/ for pictures of John =
Cole's use of a ball bearing inserted in the boom to allow easier =
lengthening of the period by reducing friction.
Frank Cooper, Friendswood, Texas, USA.  (note:thanks Larry)









Please see my web site http://freeweb.pdq.net/fxc/ for =
pictures=20
of John Cole's use of a ball bearing inserted in the boom to allow =
easier=20
lengthening of the period by reducing friction.


Frank Cooper, Friendswood, Texas, =
USA. =20
(note:thanks Larry)


From: bob ogburn 
Subject: Re: VCO into sound card
Date: Fri, 04 Sep 1998 23:00:03 -0700



Norman Davis WB6SHI wrote:

> >> For input to a PC sound card, we have considered the possibility
> >> of using a VCO (voltage controlled oscillator) IC after the
> >> seismometer pre-amp to convert the seismic signal into an FM audio
> >> tone whose frequency change is proportional to the input voltage.
> >> We use this FM-VCO method in all the analogue telemetry..... 

Is there an index or list of the station RF carrier frequency and modulation
frequency for the seismic sensors deployed in the Bay Area?



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From: johnccole@........ (john c cole)
Subject: Re: Pivot point
Date: Sat, 5 Sep 1998 05:00:04 -0500

ted
  i have no problem  at all.all recordings are clean. use two ball
bearings? an excellent idea , think that i might try it as an experiment.
   this is the thing that makes seismology so exciting. the search to
find a better way. everyone with an open mind and willing to share. it is
a pleasure to be part of such a group.
                                                          john w5auh

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From: Nick & Sophie Caporossi 
Subject: Re: Pivot point
Date: Sat, 05 Sep 1998 11:04:31 -0400

John Cole:
 I went to Frank's web page which showed your idea of using a ball bearing
at the pivot point. It is an excellent idea. Do you find that you have
difficulty keeping the ball Bearing in the center of a polished flat
surface of a bolt?
 I suspect that the center of the mass of the boom is very critical. That
is an other problem that I will have to solve. 
Is there a problem with the tendency for the boom to rotate? 

 I would like to take this opportunity to thank all those who responded to
my question of boom centering. The more I get into building a seismograph
the tantalizing the problems become. I am enjoying the dialogue.

 Nick Caporossi  

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From: johnccole@........ (john c cole)
Subject: Re: Pivot point
Date: Sat, 5 Sep 1998 12:13:44 -0500

nick
  i place the ball bearing as near to the center as possible with the
eye. if the pendulum swings to the right or left too much,move the ball
bearing with your fingers to left or right until the pendulum is roughly
centered. use the leveling legs to fine tune.once the pendulum is
repositioned , it must always be re leveled horizontally.mine never moves
from where it is placed unless i drop something on it.being able to move
this position makes it easier to level.
  to keep pendulum from rotating, drill the lead weight a little off
center, more below the center of the lead than above.when using a knife
edge i learned this trick. to sum it up, eyeball the position that it
touches the polished bolt.touch up the base level legs,then level the
pendulum. it does defy logic that it will stay in place.
                                                 
                                                       john w5auh

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From: S-T Morrissey 
Subject: USGS FM telemetry frequencies
Date: Sat, 5 Sep 1998 12:33:47 -0500 (CDT)

Here are the USGS telemetry network frequencies as used in the
New Madrid/St. Louis U. network. You can find them with a
scanner, but will have to find out locally which stations use
which. A frequency counter can determine the VCO (voltage controlled
oscillator) >>>> McGuire just hit his 60th <<<<<<<.  frequency.

Listing of USGS station channel numbers and exact frequencies.
Also indicating which stations use which channel as of  Feb. 1995

Channel	Frequency	Used At:

RF 0A	163.025000	not
RF 0B	163.175000	not
RF 1	163.609375	WCK, (TYMO)
RF 1W	163.606250	TPMO, CCMO (old)
RF 2	163.796875	LDMO, (CCTN)
RF 2W	163.793750	not
RF 3 	164.009375	DMMO, (CBL), (WYTN)
RF 3W	164.006250	not
RF 3A	164.250000	not
RF 4	164.846875	DWM, (CLAR)
RF 4W	164.843750	not
RF 5	165.809375	POW, NRMO
RF 5W	165.806250	MFTN
RF 6	166.421875	ELC, LTN
RF 6W	166.418750	(MLMO)
RF 7	166.659375	CRU, ECD
RF 7W	166.656250	(BKMO)
RF 8	167.196875	RMB, TYS
RF 8W	167.193750	(SRKY), (HMAR), (JSMO)
RF 9	167.809375	DON, NKT, (CTMO)
RF 9W	167.806250	CBMO, (WLTN), 
RF 10A	169.575000	CCMO (new)
RF 10B	170.375000	not
RF 10C	162.809300	not
RF 10D	171.215600	not
RF 11	171.406275	GRT, OKG, (HDMO)
RF 11A	171.175000	not
RF 11B	171.975000	not
RF 11C	172.100000	FVM (old)
RF 12	173.193750	LST, JHP, OHTN, FVM (new).

Comm	155.235000	Voice 2-way radios

VCO center frequencies are 680, 1020, 1360, 1700, 2040, 2380, 2720, 3060
(these are standard IRIG (inter-range-inter-governmental) frequencies
originally used for telemetry from rockets at the Nevada test range)

Regards,
Sean-THomas

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From: bob ogburn 
Subject: Re: USGS FM telemetry frequencies
Date: Sat, 05 Sep 1998 11:07:28 -0700

Sean-Thomas-
thanks for the list.  I believe that IRIG is an acronym for InterRange
Instrumentation Group.

S-T Morrissey wrote:

> Here are the USGS telemetry network frequencies as used in the
> New Madrid/St. Louis U. network. You can find them with a
> scanner, but will have to find out locally which stations use
> which. A frequency counter can determine the VCO (voltage controlled
> oscillator) >>>> McGuire just hit his 60th <<<<<<<.  frequency.
>
> Listing of USGS station channel numbers and exact frequencies.
> Also indicating which stations use which channel as of  Feb. 1995
>
> Channel Frequency       Used At:
>
> RF 0A   163.025000      not
> RF 0B   163.175000      not
> RF 1    163.609375      WCK, (TYMO)
> RF 1W   163.606250      TPMO, CCMO (old)
> RF 2    163.796875      LDMO, (CCTN)
> RF 2W   163.793750      not
> RF 3    164.009375      DMMO, (CBL), (WYTN)
> RF 3W   164.006250      not
> RF 3A   164.250000      not
> RF 4    164.846875      DWM, (CLAR)
> RF 4W   164.843750      not
> RF 5    165.809375      POW, NRMO
> RF 5W   165.806250      MFTN
> RF 6    166.421875      ELC, LTN
> RF 6W   166.418750      (MLMO)
> RF 7    166.659375      CRU, ECD
> RF 7W   166.656250      (BKMO)
> RF 8    167.196875      RMB, TYS
> RF 8W   167.193750      (SRKY), (HMAR), (JSMO)
> RF 9    167.809375      DON, NKT, (CTMO)
> RF 9W   167.806250      CBMO, (WLTN),
> RF 10A  169.575000      CCMO (new)
> RF 10B  170.375000      not
> RF 10C  162.809300      not
> RF 10D  171.215600      not
> RF 11   171.406275      GRT, OKG, (HDMO)
> RF 11A  171.175000      not
> RF 11B  171.975000      not
> RF 11C  172.100000      FVM (old)
> RF 12   173.193750      LST, JHP, OHTN, FVM (new).
>
> Comm    155.235000      Voice 2-way radios
>
> VCO center frequencies are 680, 1020, 1360, 1700, 2040, 2380, 2720, 3060
> (these are standard IRIG (inter-range-inter-governmental) frequencies
> originally used for telemetry from rockets at the Nevada test range)
>
> Regards,
> Sean-THomas
>
> _____________________________________________________________________
>
> Public Seismic Network Mailing List (PSN-L)
>
> To leave this list email listserver@............. with the body of the
> message: leave PSN-L




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From: S-T Morrissey 
Subject: Horizontal pivot
Date: Sat, 5 Sep 1998 13:09:17 -0500 (CDT)

Re. horizontal pivot:

I would like to again suggest that a taught flexible hinge or
wire be used for the boom pivot of a horizontal seis. Even if a
bearing/knife-edge setup has surfaces that are highly polished, 
say to 1 micro-inch, which is a brightly finished surface, it
movement about this surface is still large compared with the 
ground motions we are trying to record. An irregularity of 
1 micro-inch is 25 nanometers, while background earth noise is
of the order of 10 nanometers. With the flexible hinge (flexure or
taught wire), no surface contacts change as the boom moves.

I have posted the drawing of the horizontal seis that has been
used since the 50s in the WWNSS (worldwide network of standard 
seismographs) at 

http://www.eas.slu.edu/People/STMorrissey/index.html

on the page for PSN info. The design is fairly simple and should
be easy to implement. Note that the mass is suspended with a forked
wire loop from the upper pivot (which is a short taught wire), and is 
attached to both sides of the upper portion of the mass (NOT the boom), 
which prevents any rotation. 
More compact broadband horizontal sensors use miniature
flexures of the "Press-Ewing" design, or are actually inverted pendula, 
where the whole boom with the mass on top rises vertically from a 
single flexure hinge, which is also clamped to the base vertically. 
(sort of like a SG built upside down); the hinge flexure controls 
the period, and its dimensions have to be determined experimentally.

Regards,
Sean-Thomas

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From: meredith lamb 
Subject: RE: Hall-effect sensors
Date: Sat, 05 Sep 1998 13:54:32 -0600

Sean-Thomas,

Thanks for the general background review of Hall devices.  Theres
no doubt on the increased general noise factor of these critters
versus coil/magnet configurations.  Indeed the Hall's exhibit more
noise by far, than the circuit we use....perhaps 3 times the ratio,
as I remember from Bob's resistive load versus the hall tests.
If I remember right, the figure was around +-25 microvolts noise
from the hall with a no magnet, and, +- 10 microvolts with a dummy
input resistive load on the circuit itself (Hall = 15 microvolts).
I suppose for general non-precision amateur use, the noise factor
is so buried by the signal that for the most part it could be rather
ignored.  We use a LF412A, which National lists with a +- 10
microvolt drift. For comparison, a LM308 ranges up to +- 30 microvolts
per degree temperature noise/drift each unit.   Even worse, is the fact
that our tests, are kind of drawn over a day or two, and, are a meter
eyeball evaluation conclusion-ha. Bob's new circuit reduced the
electronic noise of the old circuit perhaps X2-3.  Adding the 2nd AC
amplifier noise yields a noise figure of around 35 microvolts total,
which isn't extremely too bad. Someday...we'll find a way to post the
circuit.

A brief forray into a crude shield of soft iron surrounding the Hall,
made it evident that there is some influence from the environment.
The "shield", seemed to make the "noise" drop by ~ 25%.  We've
not made any real effort todate to shield the hall's on our 2
working S-G type seismos.   At the moment, the only partial
shield, is the placement of the Hall; which is between two, 4 pole
neodymium magnets salvaged from computer surplus material.
(Hmmm....use as a geomagnetic storm sensor....interesting...)

The neodymium magnets with their rough 14K gauss field
undoubtedly overdrive the Hall into its non-linear state, but,
even here, the linearity isn't too bad from past linearity experiments.
The placement distance from the magnets has a profound impact on
output sensitivity, and thus, it is adjustable for the desired range
sought.  I've made no direct seismo measurements, but I wouldn't be
surprised to find around 65 millivolts per micron DC.  Using one 4 pole
magnet it probably drops to around 40.  Increasing the distance would
drop it further of course.   Some day I think I'll run a noise test
with a magnet versus none...the intense neo field "may" itself
be more of a diluting shield than I anticipate now.

I make no pretense as to totally understanding all of your generious
review.  More than likely, I don't reasonable ever hope to attain
a total understanding of the linear Hall aspects.  I'll also never
attain enough test equipment to delve very deeply into all the
specifics of measurements...my pocketbook isn't very deep.  Am
not too concerned about competing with precision professional
equipment here, with the no choice limitations I have.

Perhaps the key point to me, is that its simplicity, Hall/magnet
availability and adjustable zero/sensitivity/range can make it a
reasonably cheap approach to rough amateur seismic interests,
if they can't afford more precision otherwise.

We do use AC output for normal recording.  The DC part is
used for fine sensor zeroing  via the seismometer adjustment screws
and by a DMM on the circuit ground and Hall output leads.

Current problems I see (perhaps too frequently), is because of its
bridge nature; power supply fluctuations create spikes from
household  draw on the line.  Batterys are thought entertained.
Presently I use only doorbell wires from the upstairs amplifer; some
shielded wire between can help noise reduction....along with a nice
ground connection on the seismo sometime near in the future.

Hey.....I did notice you left the door open a crack for this
stumbling amateur with your statement in the last paragraph-ha.
"(although their performance might be better than some of the sensors
that are in use.)"  I presume.... you may mean like the Bosch-Omori
or Weichert class-ha.   Yes...someday I'll get back to your gamma
STM-8 project...its never been without considerable appeal to try.
I appreciate your input on this Hall stuff, as I do with all other
subjects.  One can't help but pick up juicy tidbits from your
experience.

Thanks, Meredith Lamb


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From: frankcnd@.......... (Frank Condon)
Subject: Got Magnetometer!
Date: Sat, 5 Sep 1998 14:42:58 -0700 (PDT)

Hello All:
This magnetomter is driving me up the wall with its readings from one day to 
the next. For example on Tuesday the vertical reading with an axial mu-metal 
probe was at +6,250 Gamma(nT). On September 3rd (7:30PM PDT), the reading 
went through the ceiling and was almost at the meters maximum range of 
100,000 Gamma! Specifically, it measured at approximately 83,600 Gamma(nT), 
a greater than ten-fold increase! Then, on Thursday it was back to the level 
seen on Monday at +6,100 Gamma(nT).

My question is this: What on Earth is capable of causing such a wide 
difference in readings taken only 24 hours apart at a single outdoor 
location? Also, does anyone have access to the readings from a nearby 
magnetic observatory? I'm located in the High Desert just 12 miles from the 
Cajon Pass near Victorville.
According to my information, in order to acheive such a high reading as that 
I'd have to be sitting right on the Magnetic North Pole!

September 3, 1998 (7:30PM PDT)

I give you the strangest readings seen since I started monitoring the daily 
perturbations of the Geo-Magnetic Field.

Magnetic North 49,500nT (+45,590nT)+1,266.0%

Geographic-North 46,800nT
(+42,920nT) +1,262.0%

Geo-North-East 47,100nT
(-43,150nT) +1,192.0%

Geographic-East 11,625nT 
(+10,560nT) +1,092.0%

Geo-South-East -13,225nT
(+11,530nT) +780.0%

Geographic-South -41,000nT
(+37,465nT) +1,160.0%

Geo-South-West -37,900nT 
(+34,835nT) +1,237.0%

Geographic-West -10,325nT
(+9,320nT) +1,027.0%

Geo-North-West 14,725nT
(+12,520nT) +668.0%

Vertical Down 83,600nT
(+77,550nT) +1,382.0%
--------------------------------------------------------------------

Frank Condon
"Located in the seismic corridor somewhere between Fontana & Mammoth Lakes"


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From: "Walt Williams" 
Subject: Re: Pivot point 
Date: Sat, 5 Sep 1998 14:57:03 +0000

Hello Ted, John and All,

Pardon me for intruding. In the past others and as well as recently,
Sean Morrissey suggested using resistance damping on the 
Lehman sensor coil. If I understand the reasoning, the method would 
elegantly solve the boom damping problem altogether. Or does one need 
additional damping?

Let all see if I am missing something here:

The sensor coil (if mounted on boom) moves in a strong magnetic
field, thereby generating electric current. The resistor causes a
counter field or 'back EMF' that is proportional to boom movement
which causes torque to dampen boom movement, i.e., self damping and
no additional mechanics involved. The downside, there is 
less voltage due to the added 'load' --the preamplifier gain 
"needs to be increased" to offset the difference.

An alternative method:

Copper plate(s) moving through strong magnetic field generate eddy
currents in the copper plate(s) which create a proportional field
that causes torque to dampen the boom movement, but with added mass
and volume area attached to the free end of the boom which is also
susceptible to air currents and mechanical oscillation. 

I too use the copper damping approach in my Lehman and I am planning 
to implement the electronic damping method. 

Thanks for any comments,

Walt Williams, 98.09.05
================================================

------- Forwarded Message Follows -------
Date:          Fri, 4 Sep 1998 20:51:13 -0700 (PDT)
From:          Ted Blank 
Subject:       Re: Pivot point
To:            PSN-L Mailing List 
Reply-to:      PSN-L Mailing List 

John,
I can certainly appreciate the benefit of the ball bearing approach
and I will use it if I ever build another Lehman.  However, don't you
find unwanted oscillation around the long axis of the boom?  Most of
the booms I've constructed have a fairly hefty piece of copper
attached to one end which hangs down into the magnetic field of the
damping magnets.  This weight acts like a pendulum and is very easy to
set swinging.  Would using two ball bearings a cm or so apart be
workable?  Keeping them both in contact with the polished surface
might be problematic though.  


Ted Blank
San Jose, California

On Fri, 4 Sep 1998, john c cole wrote:

> gentlemen
>   your comments  about the pivot point were correct. if you want an
> instrument with a long time period , use a ball bearing on a hard
> polished surface. i have two detectors running using the ball bearing as
> a pivot point and they will give you any time length that you want . i
> run mine at about 16 seconds. very little adjustments necessary. the
> longer the time , the more adjustment. if you place the ball bearing in
> an indention , you are back with the friction problem. try to make the
> surface that the ball bearing rest on as hard as possible to prevent
> pitting when the boom is accidently forced into the flat surface. 
>   try this method and see for yourself . you can always change it back.
>                                                              john cole
> 
> _____________________________________________________________________
> You don't need to buy Internet access to use free Internet e-mail.
> Get completely free e-mail from Juno at http://www.juno.com
> Or call Juno at (800) 654-JUNO [654-5866]
> 
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> 
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> 
> To leave this list email listserver@............. with the body of the 
> message: leave PSN-L
> 

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From: johnccole@........ (john c cole)
Subject: Re: Horizontal pivot
Date: Sat, 5 Sep 1998 16:54:36 -0500

sean
 i have two long wave seismic detectors  in operation at this time . both
work great . i tried the knife edge method and the sharp point in a small
 indentation. both methods were ok but not good enough. the ball bearing
method that i came up with works  very, very good . the question is ,can
it be made better? i have no doubt that it can. i am building another
detector at this time and it will be as you suggested. i am the new kid
on the block and have a lot to learn, so be patient with me. 
   i do not have much to offer this group in a technical way but i have a
fair mechanical ability to offer.  i will keep you informed as to how it
works  out.
     ps  any other ideas would be appreciated                            
                  john cole w5auh

_____________________________________________________________________
You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at http://www.juno.com
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From: Larry Cochrane 
Subject: Re: HKT event file
Date: Sat, 05 Sep 1998 15:48:19 -0700

At 10:12 PM 9/4/98 -0500, Charlie Thompson wrote:

>Hi Larry,
>
>Who is the HKT station?

Charlie,

The HKT event files you see are from a broadband sensor located about 200km
do east of you. I'm recording the data using the Live Internet Seismic
Server at http://www.liss.org/. I wrote a program that connects to the LISS
server and records several of the stations they have online. I have another
program that extracts PSN formatted event files from the data saved by the
other program. The  HKT event files from the Ms6.0 QUEEN CHARLOTTE ISLANDS
REGION is the first event I captured using the new software.

Currently I am monitoring the following stations:
HKT, Texas USA
GUMO, Guam
COLA, Alaska USA
KONO, Norway
KIP, Hawaii USA

See http://aslwww.cr.usgs.gov/Seismic_Data/telemetry_data/map_sta_eq.shtml
for a map of the LISS stations and recent events.

The program that saves the data currently records the BHZ, BHN and BHE 20
SPS data and the LHZ, LHN and LHE 1 SPS data. It looks like COLA only sends
LHZ and BHz data.

Today, GUMO recorded the 5.2Mb NEW BRITAIN REGION, P.N.G at 9/05 17:09.
This event is ~2000km from station. I have archived the BH* channels on my
system.

I hope to create a Web page soon that will allow anyone to access the data.
This page would be simular to the Data Request page
(http://psn.quake.net/request.html) that I already have for my local SDR data.

-Larry Cochrane
Redwood City, PSN
 

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From: "Ron Horton" 
Subject: HKT
Date: Sat, 5 Sep 1998 20:40:20 -0000

Hi all,

HKT is station code for Hockley Seismic Station in Hockly Texas. Run by =
University of Texas. Their home page is =
http://wadati.ig.utexas.edu:8000/earthquake/HKT/hkt.html

Have a great day !

Ron Horton










Hi all,


 


HKT is station code for Hockley =
Seismic Station=20
in Hockly Texas. Run by University of Texas. Their home page is http://=
wadati.ig.utexas.edu:8000/earthquake/HKT/hkt.html


 


Have a great day !


 


Ron Horton


 


From: S-T Morrissey 
Subject: review of resistive damping
Date: Sat, 5 Sep 1998 22:00:12 -0500 (CDT)


Re electromagnetic damping:

Most moving coil seismometers only use resistive damping. If properly
calculated, no other damping is needed or should be used.

To calculate the value of the damping resistor to be used, one first
has to know or determine the open circuit damping, called Bo. It
is the mechanical air-dashpot function of the coil movement, and is
often listed in the specifications for the seismometer. For most
seismometers, it ranges from 0.2 to 0.4, where a value of 0.8 is for
critical damping. It can also be determined from the logrithmic 
decrement of the free oscillations of the undamped seismometer.
(write for details on logrithmic decrement; you need a recorder or
oscilloscope to do it. It involves measuring the successive amplitudes
of undamped oscillations).

Then the motor constant and resistance of the main coil have to be
determined or found in the specifications.

The electromagnetic damping Bem needed is determined by 
subtracting the Bo from the required total Bt.
		Bem = Bt - Bo
		(If you don't know your Bo, use a value of 0.3)

Then the damping resistor is calculated by:
		Bem = G^2 / (2*omega*M*(Rs + Rd), or

		Rd = [G^2 / (Bem*2*omega*m)] - Rs

	Where Bem is the electromagnetic damping, G is the main coil
	constant, omega is the angular frequency, equivalent to 
	2*pi/Tn, where Tn is the natural period, and M is the mass.

For an L4-C, with a 5500 ohm coil, with G = 270 V/m/sec, Bo = 0.27,
we want Bt to be 0.77, so Bem = 0.5, M = 1 kgm, omega = 2*pi, we
calculate a damping resistor Rd of 6102 ohms for critical damping.

For an S5000 Long Period Seis, with a 500 ohm coil, G = 100 V/m/sec,
Bo = 0.1, we want a flatter response with Bt = 1, so Bem = 0.9,
omega = 2*pi/15 (seconds), M = 11 kg, we calculate a resistor of
705 ohms for Bt = 1 (the LP is over damped for a broader response).

For an HS-1 4.5 hz geophone with a 1250 ohm coil, G = 41 V/m/sec, and
Bo = 0.28; we want critical damping with Bt = 0.8, so Bem = 0.52,
omega = 2*pi*4.5 (hz), M = 0.022kg, we calculate Rd = 1348 ohms.

This method of damping is the only method currently being used on
velocity sensors. The method is so exact that often the resistor
for Rd is installed inside the smaller geophones at the factory.
Metal-film resistors are used for lower noise.

When one is connecting a seismometer to an amplifier with a low
input impedance Ra, that value is in parallel with the seismometer,
so must be taken into account. So if Ra = 10k ohms, and Rd is to
be 5k ohms, the actual resistor to be used is Rs = Rd*Ra/(Ra-Rd),
or in this case Rs = 10k ohms. Generally very high input impedance
amplifiers are not used because of noise considerations, so this
detail is often overlooked.

Unfortunately I have no idea what the constants for a Lehman might
be. I note that the coil is 1/4 pound of # 34 wire which has 8310 feet
per pound and 2168 ohms per pound at 20 deg.C.

So assuming the coil is about 500 ohms, I would try a damping resistor
of about 1000 ohms, unless you already know the constant G of the
main coil and can calculate the value.

With this type of damping, the response should be flat to velocity
from roughly the natural period to whatever low-pass filter you
have in your amplifier. (BTW another place to check to see if the
shorter p-wave phases are being filtered out).

The drawback of resistive damping, other than the loss of part
of the signal from the coil (made up for with less attenuation
in the recording circuitry) is that it is dissipative, and makes
noise. This is the reason it is not used in the VBB configuration,
where the damping is a dynamic process in the feedback loop. The
noise from the damping resistor is primarily Johnson or thermal
noise, which can be estimated, as well as 1/f noise. A low noise
metal film resistor does help. This noise is generally not a problem 
for most seismometer sites.

Regards,
Sean-Thomas

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From: Robert Avakian 
Subject: Re: Got Magnetometer!
Date: Sun, 06 Sep 1998 00:09:22 -0700

Could it be from a power line or industrial comples?  An anomaly of
20,000 gamma was reported in the literature at Naf Idaho, Raft River
Mts. 
We ran a survey there several years later and no anomaly was found.  The
town sits in a loop of power lines which we figured were the source of
the originally measured anomaly.  Anyone else have experience with power
lin generted anomalies?

Bob Avakian
> 
> Hello All:
> This magnetomter is driving me up the wall with its readings from one day to
> the next. For example on Tuesday the vertical reading with an axial mu-metal
> probe was at +6,250 Gamma(nT). On September 3rd (7:30PM PDT), the reading
> went through the ceiling and was almost at the meters maximum range of
> 100,000 Gamma! Specifically, it measured at approximately 83,600 Gamma(nT),
> a greater than ten-fold increase! Then, on Thursday it was back to the level
> seen on Monday at +6,100 Gamma(nT).
> 
> My question is this: What on Earth is capable of causing such a wide
> difference in readings taken only 24 hours apart at a single outdoor
> location? Also, does anyone have access to the readings from a nearby
> magnetic observatory? I'm located in the High Desert just 12 miles from the
> Cajon Pass near Victorville.
> According to my information, in order to acheive such a high reading as that
> I'd have to be sitting right on the Magnetic North Pole!
> 
> September 3, 1998 (7:30PM PDT)
> 
> I give you the strangest readings seen since I started monitoring the daily
> perturbations of the Geo-Magnetic Field.
> 
> Magnetic North 49,500nT (+45,590nT)+1,266.0%
> 
> Geographic-North 46,800nT
> (+42,920nT) +1,262.0%
> 
> Geo-North-East 47,100nT
> (-43,150nT) +1,192.0%
> 
> Geographic-East 11,625nT
> (+10,560nT) +1,092.0%
> 
> Geo-South-East -13,225nT
> (+11,530nT) +780.0%
> 
> Geographic-South -41,000nT
> (+37,465nT) +1,160.0%
> 
> Geo-South-West -37,900nT
> (+34,835nT) +1,237.0%
> 
> Geographic-West -10,325nT
> (+9,320nT) +1,027.0%
> 
> Geo-North-West 14,725nT
> (+12,520nT) +668.0%
> 
> Vertical Down 83,600nT
> (+77,550nT) +1,382.0%
> --------------------------------------------------------------------
> 
> Frank Condon
> "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


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From: Ted Blank 
Subject: Re: Horizontal pivot
Date: Sat, 5 Sep 1998 22:16:16 -0700 (PDT)

Sean-Thomas,

The "y" suspension to prevent rotation sounds much better than the 
two-ball-bearing approach.  Come to think of it, the horizontal seis I 
put in my son's school (professional model donated) is built this way but 
it's been under the floor of the school for so long I forgot what it 
looked like.  


Ted Blank
San Jose, California

On Sat, 5 Sep 1998, S-T Morrissey wrote:

> Re. horizontal pivot:
> 
> I would like to again suggest that a taught flexible hinge or
> wire be used for the boom pivot of a horizontal seis. Even if a
> bearing/knife-edge setup has surfaces that are highly polished, 
> say to 1 micro-inch, which is a brightly finished surface, it
> movement about this surface is still large compared with the 
> ground motions we are trying to record. An irregularity of 
> 1 micro-inch is 25 nanometers, while background earth noise is
> of the order of 10 nanometers. With the flexible hinge (flexure or
> taught wire), no surface contacts change as the boom moves.
> 
> I have posted the drawing of the horizontal seis that has been
> used since the 50s in the WWNSS (worldwide network of standard 
> seismographs) at 
> 
> http://www.eas.slu.edu/People/STMorrissey/index.html
> 
> on the page for PSN info. The design is fairly simple and should
> be easy to implement. Note that the mass is suspended with a forked
> wire loop from the upper pivot (which is a short taught wire), and is 
> attached to both sides of the upper portion of the mass (NOT the boom), 
> which prevents any rotation. 
> More compact broadband horizontal sensors use miniature
> flexures of the "Press-Ewing" design, or are actually inverted pendula, 
> where the whole boom with the mass on top rises vertically from a 
> single flexure hinge, which is also clamped to the base vertically. 
> (sort of like a SG built upside down); the hinge flexure controls 
> the period, and its dimensions have to be determined experimentally.
> 
> Regards,
> Sean-Thomas
> 
> _____________________________________________________________________
> 
> Public Seismic Network Mailing List (PSN-L)
> 
> To leave this list email listserver@............. with the body of the 
> message: leave PSN-L
> 

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From: frankcnd@.......... (Frank Condon)
Subject: Re: Got Magnetometer!
Date: Sat, 5 Sep 1998 22:36:52 -0700 (PDT)

Hi Bob: Thanks for your concern. No, I'm not in an industrial area, it is 
rural residential. The nearest transmission towers are 9/10 miles to the 
West and 1 mile to the South and the nearest power plant is three miles to 
the Southwest.
I heard of an anomalous reading like this prior to the Alaska "Good-Friday" 
M8.5 
earthquake, and that makes me wonder since I'm only 12 miles to the 
Northeast of the San Andreas fault!

Frank...

>Could it be from a power line or industrial comples?  An anomaly of
>20,000 gamma was reported in the literature at Naf Idaho, Raft River
>Mts. 
>We ran a survey there several years later and no anomaly was found.  The
>town sits in a loop of power lines which we figured were the source of
>the originally measured anomaly.  Anyone else have experience with power
>lin generted anomalies?
>
>Bob Avakian
>> 
>> Hello All:
>> This magnetomter is driving me up the wall with its readings from one day to
>> the next. For example on Tuesday the vertical reading with an axial mu-metal
>> probe was at +6,250 Gamma(nT). On September 3rd (7:30PM PDT), the reading
>> went through the ceiling and was almost at the meters maximum range of
>> 100,000 Gamma! Specifically, it measured at approximately 83,600 Gamma(nT),
>> a greater than ten-fold increase! Then, on Thursday it was back to the level
>> seen on Monday at +6,100 Gamma(nT).
>> 
>> My question is this: What on Earth is capable of causing such a wide
>> difference in readings taken only 24 hours apart at a single outdoor
>> location? Also, does anyone have access to the readings from a nearby
>> magnetic observatory? I'm located in the High Desert just 12 miles from the
>> Cajon Pass near Victorville.
>> According to my information, in order to acheive such a high reading as that
>> I'd have to be sitting right on the Magnetic North Pole!
>> 
>> September 3, 1998 (7:30PM PDT)
>> 
>> I give you the strangest readings seen since I started monitoring the daily
>> perturbations of the Geo-Magnetic Field.
>> 
>> Magnetic North 49,500nT (+45,590nT)+1,266.0%
>> 
>> Geographic-North 46,800nT
>> (+42,920nT) +1,262.0%
>> 
>> Geo-North-East 47,100nT
>> (-43,150nT) +1,192.0%
>> 
>> Geographic-East 11,625nT
>> (+10,560nT) +1,092.0%
>> 
>> Geo-South-East -13,225nT
>> (+11,530nT) +780.0%
>> 
>> Geographic-South -41,000nT
>> (+37,465nT) +1,160.0%
>> 
>> Geo-South-West -37,900nT
>> (+34,835nT) +1,237.0%
>> 
>> Geographic-West -10,325nT
>> (+9,320nT) +1,027.0%
>> 
>> Geo-North-West 14,725nT
>> (+12,520nT) +668.0%
>> 
>> Vertical Down 83,600nT
>> (+77,550nT) +1,382.0%
>> --------------------------------------------------------------------
>> 
>> Frank Condon
>> "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes"
>> 
>> _____________________________________________________________________
>> 
>> Public Seismic Network Mailing List (PSN-L)
>> 
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>> message: leave PSN-L
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From: "Walt Williams" 
Subject: Re: Got Magnetometer!
Date: Sat, 5 Sep 1998 23:01:56 +0000

Hello Frank,

I forwarded your magnetometer readings to one of my list members, 
Dr. Bruce Cornet, Ph.D. Paleontology. He has had much experience 
with magnetometers. He suggests that you should post the 
readings AND the UTC timestamps to enable possible corollation 
with magnetic (laboratory) databases. Perhaps CMEs are the cause, 
without the timestamp who can tell?

Also, perhaps Roger Baker may have some insight as well. He has 
been quiet lately, and his postings are missed --where are you Roger?

Best Wishes,

Walt Williams, 98.09.05
dfheli@..............
http://www.pacificnet.net/~dfheli

=======================================================
------- Forwarded Message Follows -------
Date:          Sat, 5 Sep 1998 22:36:52 -0700 (PDT)
To:            PSN-L Mailing List 
From:          frankcnd@.......... (Frank Condon)
Subject:       Re: Got Magnetometer!
Reply-to:      PSN-L Mailing List 

Hi Bob: Thanks for your concern. No, I'm not in an industrial area, it
is rural residential. The nearest transmission towers are 9/10 miles
to the West and 1 mile to the South and the nearest power plant is
three miles to the Southwest. I heard of an anomalous reading like
this prior to the Alaska "Good-Friday" M8.5 earthquake, and that makes
me wonder since I'm only 12 miles to the Northeast of the San Andreas
fault!

Frank...

>Could it be from a power line or industrial comples?  An anomaly of
>20,000 gamma was reported in the literature at Naf Idaho, Raft River
>Mts. 
>We ran a survey there several years later and no anomaly was found.  The
>town sits in a loop of power lines which we figured were the source of
>the originally measured anomaly.  Anyone else have experience with power
>lin generted anomalies?
>
>Bob Avakian
>> 
>> Hello All:
>> This magnetomter is driving me up the wall with its readings from one day to
>> the next. For example on Tuesday the vertical reading with an axial mu-metal
>> probe was at +6,250 Gamma(nT). On September 3rd (7:30PM PDT), the reading
>> went through the ceiling and was almost at the meters maximum range of
>> 100,000 Gamma! Specifically, it measured at approximately 83,600 Gamma(nT),
>> a greater than ten-fold increase! Then, on Thursday it was back to the level
>> seen on Monday at +6,100 Gamma(nT).
>> 
>> My question is this: What on Earth is capable of causing such a wide
>> difference in readings taken only 24 hours apart at a single outdoor
>> location? Also, does anyone have access to the readings from a nearby
>> magnetic observatory? I'm located in the High Desert just 12 miles from the
>> Cajon Pass near Victorville.
>> According to my information, in order to acheive such a high reading as that
>> I'd have to be sitting right on the Magnetic North Pole!
>> 
>> September 3, 1998 (7:30PM PDT)
>> 
>> I give you the strangest readings seen since I started monitoring the daily
>> perturbations of the Geo-Magnetic Field.
>> 
>> Magnetic North 49,500nT (+45,590nT)+1,266.0%
>> 
>> Geographic-North 46,800nT
>> (+42,920nT) +1,262.0%
>> 
>> Geo-North-East 47,100nT
>> (-43,150nT) +1,192.0%
>> 
>> Geographic-East 11,625nT
>> (+10,560nT) +1,092.0%
>> 
>> Geo-South-East -13,225nT
>> (+11,530nT) +780.0%
>> 
>> Geographic-South -41,000nT
>> (+37,465nT) +1,160.0%
>> 
>> Geo-South-West -37,900nT
>> (+34,835nT) +1,237.0%
>> 
>> Geographic-West -10,325nT
>> (+9,320nT) +1,027.0%
>> 
>> Geo-North-West 14,725nT
>> (+12,520nT) +668.0%
>> 
>> Vertical Down 83,600nT
>> (+77,550nT) +1,382.0%
>> --------------------------------------------------------------------
>> 
>> Frank Condon
>> "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
>
>
>_____________________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email listserver@............. with the body of the 
>message: leave PSN-L
>
>


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From: "Walt Williams" 
Subject: Re: Got Magnetometer!
Date: Sat, 5 Sep 1998 23:02:12 +0000

Hello Frank,

I forwarded your magnetometer readings to one of my list members, 
Dr. Bruce Cornet, Ph.D. Paleontology. He has had much experience 
with magnetometers. He suggests that you should post the 
readings AND the UTC time-stamp to enable possible correlation 
with magnetic (laboratory) databases. Perhaps CMEs are the cause, 
without the time-stamp who can tell?

Also, perhaps Roger Baker may have some insight as well. He has 
been quiet lately, and his postings are missed --where are you Roger?

Best Wishes,

Walt Williams, 98.09.05
dfheli@..............
http://www.pacificnet.net/~dfheli

=======================================================
------- Forwarded Message Follows -------
Date:          Sat, 5 Sep 1998 22:36:52 -0700 (PDT)
To:            PSN-L Mailing List 
From:          frankcnd@.......... (Frank Condon)
Subject:       Re: Got Magnetometer!
Reply-to:      PSN-L Mailing List 

Hi Bob: Thanks for your concern. No, I'm not in an industrial area, it
is rural residential. The nearest transmission towers are 9/10 miles
to the West and 1 mile to the South and the nearest power plant is
three miles to the Southwest. I heard of an anomalous reading like
this prior to the Alaska "Good-Friday" M8.5 earthquake, and that makes
me wonder since I'm only 12 miles to the Northeast of the San Andreas
fault!

Frank...

>Could it be from a power line or industrial comples?  An anomaly of
>20,000 gamma was reported in the literature at Naf Idaho, Raft River
>Mts. 
>We ran a survey there several years later and no anomaly was found.  The
>town sits in a loop of power lines which we figured were the source of
>the originally measured anomaly.  Anyone else have experience with power
>lin generted anomalies?
>
>Bob Avakian
>> 
>> Hello All:
>> This magnetomter is driving me up the wall with its readings from one day to
>> the next. For example on Tuesday the vertical reading with an axial mu-metal
>> probe was at +6,250 Gamma(nT). On September 3rd (7:30PM PDT), the reading
>> went through the ceiling and was almost at the meters maximum range of
>> 100,000 Gamma! Specifically, it measured at approximately 83,600 Gamma(nT),
>> a greater than ten-fold increase! Then, on Thursday it was back to the level
>> seen on Monday at +6,100 Gamma(nT).
>> 
>> My question is this: What on Earth is capable of causing such a wide
>> difference in readings taken only 24 hours apart at a single outdoor
>> location? Also, does anyone have access to the readings from a nearby
>> magnetic observatory? I'm located in the High Desert just 12 miles from the
>> Cajon Pass near Victorville.
>> According to my information, in order to acheive such a high reading as that
>> I'd have to be sitting right on the Magnetic North Pole!
>> 
>> September 3, 1998 (7:30PM PDT)
>> 
>> I give you the strangest readings seen since I started monitoring the daily
>> perturbations of the Geo-Magnetic Field.
>> 
>> Magnetic North 49,500nT (+45,590nT)+1,266.0%
>> 
>> Geographic-North 46,800nT
>> (+42,920nT) +1,262.0%
>> 
>> Geo-North-East 47,100nT
>> (-43,150nT) +1,192.0%
>> 
>> Geographic-East 11,625nT
>> (+10,560nT) +1,092.0%
>> 
>> Geo-South-East -13,225nT
>> (+11,530nT) +780.0%
>> 
>> Geographic-South -41,000nT
>> (+37,465nT) +1,160.0%
>> 
>> Geo-South-West -37,900nT
>> (+34,835nT) +1,237.0%
>> 
>> Geographic-West -10,325nT
>> (+9,320nT) +1,027.0%
>> 
>> Geo-North-West 14,725nT
>> (+12,520nT) +668.0%
>> 
>> Vertical Down 83,600nT
>> (+77,550nT) +1,382.0%
>> --------------------------------------------------------------------
>> 
>> Frank Condon
>> "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
>
>
>_____________________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email listserver@............. with the body of the 
>message: leave PSN-L
>
>


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From: David Josephson 
Subject: Re: Got Magnetometer
Date: Sat, 5 Sep 1998 23:14:39 -0700 (PDT)

From the readings you gave, you have not got magnetometer. Something
is broken. The magnitude of diurnal variations and the worst magnetic
storms in the US is on the order of a few hundred to maybe a 
thousand nT.

-- 
David Josephson / Josephson Engineering / San Jose CA / david@.............

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From: frankcnd@.......... (Frank Condon)
Subject: Re: (Fwd) Re: Got Magnetometer!
Date: Sun, 6 Sep 1998 01:27:36 -0700 (PDT)

Walt:
I certainly appreciate you taking the time to help me figure this out.
I have a nearly steady reading taken at dusk 0330 UTC 09/04/98 that lasted 
for at least the next couple of hours that I kept monitoring it.  Afterward, 
I removed the instrument to a sheltered location about 100 feet to the 
southeast and took a second reading of the vertical intensity that showed 
the same higher than normal reading. That was specifically on September 3, 
1998 - local time. I've got a Rustrak recorder that I'm going to hook up to 
the output of the magnetometer and keep a running strip chart record of 
readings from now on. I have to admit that it somewhat caught me off-guard . 
But, I know what I was observing on that magnetometer wasn't normal for us. 
The frequency response of this fluxgate magnetometer is rated from DC up to 
5 Hertz, and is using a 4-1/2" taut-band meter. 

Frank...


>Hello Frank,
>
>I forwarded your magnetometer readings to one of my list members, 
>Dr. Bruce Cornet, Ph.D. Paleontology. He has had much experience 
>with magnetometers. He suggests that you should post the 
>readings AND the UTC timestamps to enable possible corollation 
>with magnetic (laboratory) databases. Perhaps CMEs are the cause, 
>without the timestamp who can tell?
>
>Also, perhaps Roger Baker may have some insight as well. He has 
>been quiet lately, and his postings are missed --where are you Roger?
>
>Best Wishes,
>
>Walt Williams, 98.09.05
>dfheli@..............
>http://www.pacificnet.net/~dfheli
>
>=======================================================
>------- Forwarded Message Follows -------
>Date:          Sat, 5 Sep 1998 22:36:52 -0700 (PDT)
>To:            PSN-L Mailing List 
>From:          frankcnd@.......... (Frank Condon)
>Subject:       Re: Got Magnetometer!
>Reply-to:      PSN-L Mailing List 
>
>Hi Bob: Thanks for your concern. No, I'm not in an industrial area, it
>is rural residential. The nearest transmission towers are 9/10 miles
>to the West and 1 mile to the South and the nearest power plant is
>three miles to the Southwest. I heard of an anomalous reading like
>this prior to the Alaska "Good-Friday" M8.5 earthquake, and that makes
>me wonder since I'm only 12 miles to the Northeast of the San Andreas
>fault!
>
>Frank...
>
>>Could it be from a power line or industrial comples?  An anomaly of
>>20,000 gamma was reported in the literature at Naf Idaho, Raft River
>>Mts. 
>>We ran a survey there several years later and no anomaly was found.  The
>>town sits in a loop of power lines which we figured were the source of
>>the originally measured anomaly.  Anyone else have experience with power
>>lin generted anomalies?
>>
>>Bob Avakian
>>> 
>>> Hello All:
>>> This magnetomter is driving me up the wall with its readings from one day to
>>> the next. For example on Tuesday the vertical reading with an axial mu-metal
>>> probe was at +6,250 Gamma(nT). On September 3rd (7:30PM PDT), the reading
>>> went through the ceiling and was almost at the meters maximum range of
>>> 100,000 Gamma! Specifically, it measured at approximately 83,600 Gamma(nT),
>>> a greater than ten-fold increase! Then, on Thursday it was back to the level
>>> seen on Monday at +6,100 Gamma(nT).
>>> 
>>> My question is this: What on Earth is capable of causing such a wide
>>> difference in readings taken only 24 hours apart at a single outdoor
>>> location? Also, does anyone have access to the readings from a nearby
>>> magnetic observatory? I'm located in the High Desert just 12 miles from the
>>> Cajon Pass near Victorville.
>>> According to my information, in order to acheive such a high reading as that
>>> I'd have to be sitting right on the Magnetic North Pole!
>>> 
>>> September 3, 1998 (7:30PM PDT)
>>> 
>>> I give you the strangest readings seen since I started monitoring the daily
>>> perturbations of the Geo-Magnetic Field.
>>> 
>>> Magnetic North 49,500nT (+45,590nT)+1,266.0%
>>> 
>>> Geographic-North 46,800nT
>>> (+42,920nT) +1,262.0%
>>> 
>>> Geo-North-East 47,100nT
>>> (-43,150nT) +1,192.0%
>>> 
>>> Geographic-East 11,625nT
>>> (+10,560nT) +1,092.0%
>>> 
>>> Geo-South-East -13,225nT
>>> (+11,530nT) +780.0%
>>> 
>>> Geographic-South -41,000nT
>>> (+37,465nT) +1,160.0%
>>> 
>>> Geo-South-West -37,900nT
>>> (+34,835nT) +1,237.0%
>>> 
>>> Geographic-West -10,325nT
>>> (+9,320nT) +1,027.0%
>>> 
>>> Geo-North-West 14,725nT
>>> (+12,520nT) +668.0%
>>> 
>>> Vertical Down 83,600nT
>>> (+77,550nT) +1,382.0%
>>> --------------------------------------------------------------------
>>> 
>>> Frank Condon
>>> "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
>>
>>
>>_____________________________________________________________________
>>
>>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
>
>_____________________________________________________________________
>
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>
>To leave this list email listserver@............. with the body of the 
>message: leave PSN-L
>
>


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From: frankcnd@.......... (Frank Condon)
Subject: Re: Got Magnetometer
Date: Sun, 6 Sep 1998 02:00:18 -0700 (PDT)

David:
You have given me sound reason to question the reliability of this 
instrument. It's only been in my possesion for the last two weeks and was 
supposedly checked out by the dealer before shipping it to me on 8/14/98. I 
won't mention any names here, but it does begin with the letter "T" like in 
Texas. The learning curve is steep when you are first starting out. Since 
then I've read the book by LL. Nettleton "Elementary Gravity and Magnetics 
for Geologists and Seismologists", and the "Applications Manual for Portable 
Magnetometers" by S. Breiner. After reading your reply and before finishing 
this reply I have discovered an intermittent loose front panel connector 
(missing ground) going to the probe that is suspect for causing the 
anomalous false alarm. Probably a long story to tell you how it got that 
way, but it looks like the mystery is solved until the next time around. 
Right now, the reading is incorrectly at 64,000 Gamma! So much for late 
night troubleshooting... I'll fix it in the morning... Yawn!

Thank you,
Frank Condon

>>From the readings you gave, you have not got magnetometer. Something
>is broken. The magnitude of diurnal variations and the worst magnetic
>storms in the US is on the order of a few hundred to maybe a 
>thousand nT.
>
>-- 
>David Josephson / Josephson Engineering / San Jose CA / david@.............
>
>_____________________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email listserver@............. with the body of the 
>message: leave PSN-L
>
>


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From: Bob Fryer 
Subject: Re: Got Magnetometer!
Date: Sun, 6 Sep 1998 03:09:38 -0700

Hello Frank, et al.,

A friend, Ali R. -- who lives near Palmdale -- on the San Andreas fault,
has measured some interesting anomalies for a period of years.  But she
doesn't have a magnetometer.  Her (quality) compass will sometimes swing as
much as much as 15 degrees off north; an ohmmeter measuring resistance in
the ground will vary from 50 to 2500 (independent of changes in moisture);
and a carpenter's brass plumb-bob, suspended from a seven-foot ceiling over
a target on the floor, will wander more than 1/2" off of vertical.  We
associate these variations with stress-induced changes in the
electromagnetic fields along the fault.  There are also significant daily
variations in the water levels in her two wells, which are independent of
each other, and independent of the normal seasonal changes, her domestic
use, and the neighbor's experience.

We are building up the material so that we can present this information on
my www page.

Take care,
Bob -- on the Cascadia Subduction Zone

PS
I am preparing to go to California again.  Perhaps we could arrange a tour
of her place late this month (You are not that far from her). (Ali was
featured in a segment recently on PBS -- The Savage Earth -- she is very
sensitive to the changes.  Also, she is featured in "A Sense of Disaster,"
showing on BBS this month, and on The Discovery Channel -- here -- in
October.)  While traveling, my E-mail address is 72164,2537@.............. .
B.


>Hello All:
>This magnetomter is driving me up the wall with its readings from one day to
>the next. For example on Tuesday the vertical reading with an axial mu-metal
>probe was at +6,250 Gamma(nT). On September 3rd (7:30PM PDT), the reading
>went through the ceiling and was almost at the meters maximum range of
>100,000 Gamma! Specifically, it measured at approximately 83,600 Gamma(nT),
>a greater than ten-fold increase! Then, on Thursday it was back to the level
>seen on Monday at +6,100 Gamma(nT).
>
>My question is this: What on Earth is capable of causing such a wide
>difference in readings taken only 24 hours apart at a single outdoor
>location? Also, does anyone have access to the readings from a nearby
>magnetic observatory? I'm located in the High Desert just 12 miles from the
>Cajon Pass near Victorville.
>According to my information, in order to acheive such a high reading as that
>I'd have to be sitting right on the Magnetic North Pole!
>
>September 3, 1998 (7:30PM PDT)
>
>I give you the strangest readings seen since I started monitoring the daily
>perturbations of the Geo-Magnetic Field.

SNIP
>
>Frank Condon
>"Located in the seismic corridor somewhere between Fontana & Mammoth Lakes"
>
>__________________________________________________________________
>Public Seismic Network Mailing List (PSN-L)

----- earthquake WARNING research -----
--- animals, people, scientific evidence ---
---  http://www.teleport.com/~bfryer ---



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From: CARRJJ@.......
Subject: Re: Got Magnetometer!
Date: Sun, 6 Sep 1998 13:18:44 EDT

Assuming no defects with the circuit, how close are you to Edwards AFB. You
could be "measuring" electromagnetic interference and not magnetic fields at
all.

Joe Carr

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From: Roger Baker 
Subject: Where I'm at
Date: Sun, 06 Sep 1998 12:14:20 -0500


>Also, perhaps Roger Baker may have some insight as well. He has=20
>been quiet lately, and his postings are missed --where are you Roger?
>
>Best Wishes,
>
>Walt Williams, 98.09.05
>dfheli@..............
>http://www.pacificnet.net/~dfheli

Friends,
          Lately I have been what I think is referred to in the cyberworl=
d
as 'lurking', on this list.
=20
I do have other parallel lives, namely as an investor and fairly
controversial writer on politics, economics, transportation policy and so
forth, most of which is off-topic on this list. I also like to hold court
on a bunch of other lists. I do think these e-mail lists are one of the
great human inventions of all time, and consider PSN to be the very best
anywhere near to my area of general amateur science.

As you may recall, some of my last postings were on my magnetic spring
vertical seismo with an optical displacement detector mounted inside a
mu-metal shield and surrounded by an isothermal enclosure. It works quite
well both as a tidal gravimeter (since its response goes down to DC) and =
as
a tele-seismograph so far as I can tell, and I did post a few charts to
John Lahr and Larry just to prove it worked. But to convince a sceptical
world that such a design is practical (as you may recall, my proposals we=
re
greeted with some scepticism by Sean Thomas), and after having posted a
prose description and a few photographs to Larry, one really needs to hav=
e
a web site with circuit diagrams.=20

So I vowed to post all the details of my vertical -- which I call the Hi-=
Q=20
-- based on the fact that it achieves a lot of its performance from a
combination of a high Q magnetic spring in combination with active feedba=
ck
-- on a web site. But this involves learning web site construction in
competition with all the other irons I have in the fire, and you know how
that goes.=20

And I'm kind of a scientific vagabond of instrumentation, trying to inven=
t
and maybe patent a super-accurate densimeter at the moment. My delight is
in inventing and not collecting seismographic data, and once something is
invented the challenge is gone and my attention drifts to other areas...

But I do have the following offering on the topic of magnetometry, which =
I
submitted as a Science hacker column to the Society for Amateur Scientist=
's
Journal edited by Jack Herron last January. It was never published, and I
now have my doubts whether my Science Hacker column will ever be publishe=
d,
given the numerous chronic delays and problems within the SAS organizatio=
n.
But here is that piece complete minus the illustrations, which I should
probably post on a web site, once I ever get around to learning the basic=
s
of web page design, whenever that happens.

                                                  --Yours, Roger

************************************************************************

    How to build a Small, Cheap, Supersensitive Magnetometer for $5

                    By Roger Baker, January, 1998

Such a deal!  Actually when you get into the fine print in this column, i=
t
turns out that this is about how to build a  torsion magnetometer, and th=
e
stripped down essential part starts at about five bucks, assuming you got=
 a
well-stocked junk pile.  And we=92ll suppose your spiffy friend loans you=
 a
$30 laser pointer so you can watch a red spot dance around on the wall in
response to magnetic fluctuations. =20

A magnetometer built as described should be able to see cars pass at 50
feet, and should allow you to see the short term magnetic fluctuations
which somewhat resemble heartbeats, called magnetic pulsations, as well a=
s
magnetic storm events.=20

We end up with an instrument in several parts (a magnetometer, a balancin=
g
magnet, a laser pointer, and the wall). It is portable, but is normally
meant to detect slow fluctuations up to a few cycles per second from a
fixed position. Such detectable magnetic pulsations extend up through the
audio frequencies.

There are many ways to detect magnetic fields known to physicists includi=
ng
Hall effect devices, which are tiny but not very sensitive, and flux gate=
s
starting at about $50. Magnetometers tend to get expensive fast and invol=
ve
exotic physics when they get more sensitive than a simple torsion
instrument, since they usually involve particle physics, atomic light
emission spectra, superconductivity, etc.=20

So we will proceed by hanging tiny bits of mirror and a tiny pair of rare
earth magnets from a tiny fiber.  We  will use a laser pointer to bounce
light off the little chips of flat mirror. (Note: there are many other
possible experimental uses for this simple fiber suspension technique, li=
ke
supersensitive balances with little beams suspended from a torsion fiber)=
.. =20

The first step is to go to the hardware store and buy some glossy, silky
nylon twine. Then unravel about a one foot section into lesser strands, a=
nd
learn to pull single fibers roughly a thousandth of an inch in diameter o=
ut
of these strands. One piece of twine contains enough fibers to last
forever, probably. Nylon is nice although it drifts because it is strong,
safe,  easy to get, and forgiving to the clumsy. Quartz is the best fiber
for torsion instruments (but the type used for fiber optics tends to be t=
oo
thick). =20

We start by building a taut nylon fiber suspension within a kind of flat
glass case.  A square foot of plain window glass which we cut into two
strips 2 in wide and 6 in. long with a carbide wheel glasscutter. Then we
silicone glue two stacks of glass to each end. Each stack is two pieces
high, made of  glass strips 1/2 by 2 in =20

This will make raised plateaus on each end. After the rubber is set, we
face the plateaus with stretchy black vinyl electrical tape to keep the
edges of the glass from cutting into the fiber. Then we stretch a nylon
fiber between two of these plateaus and tape it in place with more black
tape.  We tape the fiber to top half, letting the fiber hang vertically,
and then tape a stack of four nickels to the lower end of the fiber. This
stretches the fiber before we tape the bottom end too, locking in this
tension. =20

We now have a microscopic tensioned fiber spanning a gap. The next step i=
s
to use silicone rubber to glue two tiny rare earth magnets from Radio Sha=
ck
to the middle of the fiber. They will leap to cling to each other, so we
smear one magnet with silicone and position it it in the middle of the
fiber, supported from below while the rubber sets. Then we let the other
magnet jump into place and nudge them onto good symmetry, sandwiching the
fiber in the middle.=20

To make mirror chips, I cut a piece from a glass vanity mirror. Rub the
protective lacquer off using methyl ethyl ketone ketone or similar solven=
t
to expose the bare silver. This gives a front surface mirror that can be
cut to little pieces a millimeter or two square with a glass cutter.  We
glue two similar mirror chips with silicone, silvered sides out,
immediately to one side and touching the magnet pair. These are pushed
together to contact and trap the filament, in similar fashion to the
magnets grasping the fiber. The resulting magnet/mirror mass should have
good rotational balance, like the well-balanced wheel of a car on a
horizontal axle.=20

Finally, in a strange twist of instrument design, I silicone a copper
(pre-1980 or so) penny flat to the inside of the glass strip facing the
magnet/mirror, positioned so that its free rotation is not blocked.  The
copper greatly helps to kill unwanted magnet/mirror oscillations by
inducing lossy eddy currents.

Now put the second strip of glass with spacers on top to enclose the fibe=
r,
magnet, and mirror in a sort of flat transparent glass shell. The stacks =
of
glass spacers hold the six inch strips strips of glass about 1/2 in apart
at each end. When everything is properly arranged, we use black vinyl tap=
e
to hermetically seal the chamber from air currents along the open sides. =
We
have easy optical access to the side of the glass case which isn=92t cove=
red
by the penny.=20

The instrument is now a good compass. If you walk around the room holding
this gadget, the magnet/mirror should rotate on the fiber in an interesti=
ng
and obedient manner with little oscillation.

This magnetometer suspension can be used to detect different vectors of
magnetic force by tilting the axis of the nylon fiber in any appropriate
direction. A vertical fiber instrument usually gives better sensitivity
than a horizontal position and is much more convenient. If we wanted to
measure magnetic fields in space, which geophysicists routinely do to
extract interesting information, we would need three such magnetometers,
with their fibers aligned along the X,Y and Z axes. Since a torsion
suspension is sensitive to twisting force, the greatest sensitivity is to=
 a
magnetic force is in the plane of rotation and 45 degrees to each side of
the the face of the magnetic discs.

The last step is to null or balance the earth=92s magnetic field as nearl=
y as
possible with a nulling magnet. An earth field nulling magnet is made by
cementing four Radio Shack donut magnets flat, pushed together despite
repulsion, to a wide strip of glass using silicone rubber.  Use clothes
pins to hold them until the rubber has set. This makes a kind of magnetic
paddle which can be mounted on a glass base.=20

Actually, the earth=92s field is pointed is pointed through space like a
tilted arrow.  The ideal way to cancel out the earth field would involve
positioning the nulling magnet in the reverse direction along the same ti=
lt
to create a zone surrounding the magnet/mirror where the earth field is
nearly balanced down to a zero net field. In practice it is easier to
adjust and detect horizontal vectors of magnetic force using a flat table=
top.
=20
The nulling magnet and the magnetometer can be mounted on little pedestal=
s
and moved or rotated in any position, while everything remains at the
height of the magnet/mirror. The laser pointer is held  =93on=94  with a
clothespin and propped horizontally to one side, pointed at the
magnet/mirror, and the reflected red spot is viewed on the wall.

Working on a flat surface, one should approach the magnetometer from the
direction that the magnet pair is facing on the vertical fiber, from
somewhere in line with the magnet=92s axis of rotation, and with the magn=
etic
paddle squarely facing the flat side of the suspended magnet. From one
direction, it will pull the magnet into stronger alignment, but from the
other direction it will cause the pair to suddenly flip as it approaches.
Which way the pair flips is defendant on the exact position of the paddle.
As one slowly approachrs the pair from this direction, it will begin to
wobble and rotate when the field from the paddle very nearly balances the
earth=92s field.=20

There is a point in space such that the combined force of gravity, the
torsion of the fiber, and the external influence of the surrounding
magnetic field is nearly zero. Here we get the maximum rotation of the
suspended magnet/mirror with the least external force, making the
instrument highly sensitive. This condition can be seen by a lengthening =
of
the natural oscillation period to a second or more. The sensitivity will =
be
a little different each time the adjustments are made but reasonably stab=
le.

We should now have an instrument sensitive to perhaps a gamma or nanoTesl=
a
(which are the same thing, and both equal to about one 50,000th part of t=
he
earth=92s magnetic field. Typically micropulsations are a few gamma in
amplitude). You can play with this instrument by watching the laser point=
er
beam shift around on the wall as cars drive by, screen visitors for
pocketknives and handguns, etc.  One can rig the laser pointer to get pow=
er
from two large alkaline batteries to operate for weeks rather than about
twelve hours, and thus make a semi-permanent display for viewing solar
flares, etc. =20

Many embellishments are possible. Helmholtz coils may be used for
calibration using simple formulas. Serious amateurs can wind a pair of
Helmholtz coils on a rolled oats container to make a feedback version of
this instrument which can keep a laser spot exactly centered on a
photocell. The strength of this fine-tuning feedback field can then be us=
ed
to make a continuous chart of the magnetic field fluctuations by feeding
the electronic signal from the feedback circuit into a computer. A $100
DATAQ module from Radio Shack works well for me.

The best and most reable readable introduction to geomagnetometry is
probably =93Introduction to Geomagnetism=94, Elsevier, by W.D. Parkinson
(1982?). Pages 299-307 have basic information on the origin of the variou=
s
frequencies of geomagnetic pulsations. =20



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From: CARRJJ@.......
Subject: Re: Got Magnetometer!
Date: Sun, 6 Sep 1998 13:23:48 EDT

In a message dated 98-09-06 01:12:11 EDT, you write:

<< psn-l@............. >>
===========================

The possibility of RF EMI should not be overlooked.

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From: Robert Avakian 
Subject: Re: Got Magnetometer!
Date: Sun, 06 Sep 1998 15:30:20 -0700

If the anomaly does have something to do with a quake, you'd better have
you seatbelt fastened :-)

Bob
> 
> Hi Bob: Thanks for your concern. No, I'm not in an industrial area, it is
> rural residential. The nearest transmission towers are 9/10 miles to the
> West and 1 mile to the South and the nearest power plant is three miles to
> the Southwest.
> I heard of an anomalous reading like this prior to the Alaska "Good-Friday"
> M8.5
> earthquake, and that makes me wonder since I'm only 12 miles to the
> Northeast of the San Andreas fault!
> 
> Frank...
> 
> >Could it be from a power line or industrial comples?  An anomaly of
> >20,000 gamma was reported in the literature at Naf Idaho, Raft River
> >Mts.
> >We ran a survey there several years later and no anomaly was found.  The
> >town sits in a loop of power lines which we figured were the source of
> >the originally measured anomaly.  Anyone else have experience with power
> >lin generted anomalies?
> >
> >Bob Avakian
> >>
> >> Hello All:
> >> This magnetomter is driving me up the wall with its readings from one day to
> >> the next. For example on Tuesday the vertical reading with an axial mu-metal
> >> probe was at +6,250 Gamma(nT). On September 3rd (7:30PM PDT), the reading
> >> went through the ceiling and was almost at the meters maximum range of
> >> 100,000 Gamma! Specifically, it measured at approximately 83,600 Gamma(nT),
> >> a greater than ten-fold increase! Then, on Thursday it was back to the level
> >> seen on Monday at +6,100 Gamma(nT).
> >>
> >> My question is this: What on Earth is capable of causing such a wide
> >> difference in readings taken only 24 hours apart at a single outdoor
> >> location? Also, does anyone have access to the readings from a nearby
> >> magnetic observatory? I'm located in the High Desert just 12 miles from the
> >> Cajon Pass near Victorville.
> >> According to my information, in order to acheive such a high reading as that
> >> I'd have to be sitting right on the Magnetic North Pole!
> >>
> >> September 3, 1998 (7:30PM PDT)
> >>
> >> I give you the strangest readings seen since I started monitoring the daily
> >> perturbations of the Geo-Magnetic Field.
> >>
> >> Magnetic North 49,500nT (+45,590nT)+1,266.0%
> >>
> >> Geographic-North 46,800nT
> >> (+42,920nT) +1,262.0%
> >>
> >> Geo-North-East 47,100nT
> >> (-43,150nT) +1,192.0%
> >>
> >> Geographic-East 11,625nT
> >> (+10,560nT) +1,092.0%
> >>
> >> Geo-South-East -13,225nT
> >> (+11,530nT) +780.0%
> >>
> >> Geographic-South -41,000nT
> >> (+37,465nT) +1,160.0%
> >>
> >> Geo-South-West -37,900nT
> >> (+34,835nT) +1,237.0%
> >>
> >> Geographic-West -10,325nT
> >> (+9,320nT) +1,027.0%
> >>
> >> Geo-North-West 14,725nT
> >> (+12,520nT) +668.0%
> >>
> >> Vertical Down 83,600nT
> >> (+77,550nT) +1,382.0%
> >> --------------------------------------------------------------------
> >>
> >> Frank Condon
> >> "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
> >
> >
> >_____________________________________________________________________
> >
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> >
> >To leave this list email listserver@............. with the body of the
> >message: leave PSN-L
> >
> >
> 
> _____________________________________________________________________
> 
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> 
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From: meredith lamb 
Subject: A S-G horizontal using Coil/magnet question
Date: Sun, 06 Sep 1998 15:28:46 -0600

Got to thinking today, that right off, I don't know of any
amateur who uses the S-G variety, that has the usual coil and
magnet output?  Anybody out there tried it?  Naturally they
would be short period....but probably very good and reliable
instruments in active areas, with their zero drift characteristics
(for the most part).

Meredith Lamb

P.S., no, I'am not giving up the Hall sensor-ha.


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From: George Bush 
Subject: Re: Got Magnetometer!
Date: Sun, 06 Sep 1998 17:10:33 -0700

At 02:42 PM 9/5/98 -0700, you wrote:
>Hello All:
>...snip...>
>My question is this: What on Earth is capable of causing such a wide 
>difference in readings taken only 24 hours apart at a single outdoor 
>location? 

Frank-
	It may not be "on Earth." I am also an am. astronomer and have been
watching a monstrous double sunspot rotate across the face of the sun. The
width of the thing is more than 10% of the Sun's diameter! This spot should
rotate to the back in a few days. If there is any connection, you may see
your magnetometer activity drop.


George

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From: Larry Cochrane 
Subject: Re: A S-G horizontal using Coil/magnet question
Date: Sun, 06 Sep 1998 20:26:14 -0700

Meredith,

I've been think about it... It would be very easy to add another coil and
magnet to the SG sensor. This would be a short period velocity output that
could be amplified with one of my Amp / Filter cards. Hope to try it
someday...

-Larry Cochrane
Redwood City, PSN


At 03:28 PM 9/6/98 -0600, you wrote:
>Got to thinking today, that right off, I don't know of any
>amateur who uses the S-G variety, that has the usual coil and
>magnet output?  Anybody out there tried it?  Naturally they
>would be short period....but probably very good and reliable
>instruments in active areas, with their zero drift characteristics
>(for the most part).
>
>Meredith Lamb
>
>P.S., no, I'am not giving up the Hall sensor-ha.
>
>
>_____________________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email listserver@............. with the body of the 
>message: leave PSN-L
>

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From: meredith lamb 
Subject: Re: A S-G horizontal using Coil/magnet question
Date: Sun, 06 Sep 1998 23:39:24 -0600



Larry Cochrane wrote:

> Meredith,
>
> I've been think about it... It would be very easy to add another coil and
> magnet to the SG sensor. This would be a short period velocity output that
> could be amplified with one of my Amp / Filter cards. Hope to try it
> someday...
>
> -Larry Cochrane
> Redwood City, PSN
>

Larry,

Yes that sounds like a very good add-on for your unit.  Would
make a very convenient addition to what I would consider a
reliable and very low maintenance seismo (mechanically).  You
may have to increase the damping a hair I would expect, unless
compensating mass weight is removed.   Short and broad band
in one....very good.

Would guess your card would work right off the bat, with no
additions or subtractions of the circuit.  Use your amplifiers
on my Sprengnethers and have never had to touch them since
setup some odd 3 months ago....I like that.   I figure you didn't
put on any pots for reliablity, and it seems to work better for it.

Still haven't messed with any real insulation for my S-G types.
Actually; they don't give any indication of any real need for a
strong temp controlled covering "box".  The Hall's only dissipate
some 6.5ma, and damping is aluminum/magnet eddy current, so
for the most part their is no heat generators.  Seems like, as long
as the adjustment screws are relatively locked with nuts both
above and below the base plates, the mass just doesn't wander
very much.   I'll likely make some better insulated boxes eventually,
for some other trial ideas.

I also considered the addition of a coil/magnet to my S-G's, but,
need to do more Hall work.  Actually...a vrdt on the S-G sounds
very interesting too, as Sean-Thomas brought up awhile back.

Meredith Lamb






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From: meredith lamb 
Subject: Correction....
Date: Mon, 07 Sep 1998 00:39:39 -0600

Larry,

I forgot about the gain adjustments trimpots on your amplifier
circuit boards.  Probably I suffer from set-um and forget-um
syndrome, or perhaps its the influence of the tektite atop the
Sprengnether mass interfering with my brain wave patterns,
or........ha.

Meredith Lamb




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From: "Frank Cooper" 
Subject: THANKS KARL CUNNINGHAM
Date: Mon, 7 Sep 1998 11:12:32 -0500

I want to publicly thank Karl Cunningham for taking his time and effort =
to pack and ship two chart recorders to another PSN member for only =
shipping charges. Karl could have sold the recorders or otherwise =
disposed of them locally with far less trouble than shipping them to me. =
The Esterline Angus and Gould Brush Mark 220 are in working condition.  =
I plan to use the Esterline Angus to record the output of my S-G sensor =
(in addition to digital recording) when completed.  I am currently =
digitally recording the output of a Lehman sensor.  The output of the =
Lehman has also been monitored with an Esterline Angus chart recorder =
since January, 1997.  I am going to attempt to adapt the two channel =
Gould straight line recording mechanism to a rotating drum.

Thanks again Karl.

Frank Cooper, Friendswood, Texas, USA









I want to publicly thank Karl Cunningham for taking =
his time=20
and effort to pack and ship two chart recorders to another PSN member =
for only=20
shipping charges. Karl could have sold the recorders or otherwise =
disposed of=20
them locally with far less trouble than shipping them to me. The =
Esterline Angus=20
and Gould Brush Mark 220 are in working condition.  I plan to use =
the=20
Esterline Angus to record the output of my S-G sensor (in addition to =
digital=20
recording) when completed.  I am currently digitally recording the =
output=20
of a Lehman sensor.  The output of the Lehman has also been =
monitored with=20
an Esterline Angus chart recorder since January, 1997.  I am going =
to=20
attempt to adapt the two channel Gould straight line recording mechanism =
to a=20
rotating drum.


 


Thanks again Karl.


 


Frank Cooper, Friendswood, Texas,=20
USA


From: meredith lamb 
Subject: Re: THANKS KARL CUNNINGHAM
Date: Mon, 07 Sep 1998 11:10:16 -0600

Karl Cunningham,

 APPLAUSE!!!!!  Generiousity is a measure of a good person.

Frank,

OK.....now, you're making a S-G.  So,....give some more
details.  Its like a couple having a child and only saying its a
homo-erectus species, and leaving off all the other details - ha.
Whats your plans for its genetic makeup?

The Nosey Neanderthal...Meredith Lamb


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From: S-T Morrissey 
Subject: SG as VBB?
Date: Mon, 7 Sep 1998 12:43:51 -0500 (CDT)

Meredith, Larry, Frank, and co.,

My suggestion for the SG pendulum: (an alternative solution
to the damping questions)

Why not simply configure it as a VBB with triple feedback?

You already have many options for a displacement detector, and already
have a coil-magnet for the force coil (the coil is on the boom).
You also have some basic electronics at hand for the detector, so
adding an integrator amplifier should not be a problem. Possibly 
some modifications of Larry's SG board would take care of everything.

Damping of a VBB is accomplished by the feedback loop, specifically by
the value of the proportional resistor. Fedback damping is not 
dissipative as is resistive, eddy current, etc., so  those noise
sources are avoided.

So if  one wanted to extend the period of the SG, there is 
no reason that the triple feedback used in the STM cannot be used.
All it needs is a good displacement detector and a strong feedback
coil attached to a pendulum of reasonable period Tn. A one second Tn
will work, but I think that your 4 lb mass might be too much unless
you have a very powerful coil-magnet. With the S5000 seis with the 11 kg
mass the coil constant is nearly 100 Newtons/Ampere. With the STM
seis with 0.5 kg mass, the constant is 12 N/A. A large mass is not
necessary for a fedback system other than to reduce Brownian noise, 
where M*T*Q should be greater than 1 (for the reader: M= mass in kg, 
T = period in seconds, and Q is the inverse of the mechanical damping: 
Bo. (for a closed seis like a L4-C, Bo = 0.25, so Q = 4; for a quartz 
fiber torsion suspension, where the mass will oscillate almost indefinitely, 
Bo might be 0.01, so Q would be 100, allowing a much smaller mass..  

The problem as I see it is making a homemade feedback coil with a 
large generator constant, which is why I tried the stereo speaker.
The coil constant can be determined on the seismometer by a setup
that pulls horizontally on the boom at the the coil with a thread with 
a 90 deg V in it with the test weight at the base of the V, so it 
applies half of the test force horizontally to the boom. Then an 
adjustable current (from a battery and a pot and a meter) through the 
coil is used to return the boom to the center position).

Then the weight (divided by two in the horizontal setup) in Kgrams 
is multiplied by g (9.806m/sec^2) and divided by the current in Amperes 
to get Newtons/Ampere. (actually grams*g/milliamperes gives the same result).
When I determine the constant of the speaker coil by force balance, 
1 gram is balanced by 0.755ma, for a constant of 12.988 N/A, 

Another 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.  Hopefully you would have
information on the strength of the magnet. Then G = B * L *10 **-6 N/A.
(The length L can also be determined by knowing the wire size and
the resistance and looking it up in a table of wire parameters).
(Also, one could use this method to actually determine the strength
of the magnet by doing the force balance first to determine G).

One could model the transfer function of a  VBB-SG using the triple
feedback if one new the sensitivity of the displacement detector, (which
can be scaled by the displacement amplifier to whatever is needed),
as well as the mass, the coil constant, and the period.
else one could assume some values. I think it should be easy to make 
the 1 second pendulum perform as a 30 second broadband sensor.
The transfer function will provide values for the differential 
capacitor, the proportional resistor, the integrator period, and the
integral feedback resistor. (The function recently worked quite nicely
in configuring a 4.5 hz geophone work at 21 seconds (but with a 29 gram
mass, MTQ is poor, like 0.032!, so it is 100x noisier than the STM-8);
it has recorded several teleseisms, like the 6.7 in the Phillipines).

Regards,
Sean-Thomas

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From: meredith lamb 
Subject: Re: SG as VBB?
Date: Mon, 07 Sep 1998 15:48:56 -0600

Sean-Thomas,

I do have a surplus source for linear motor coils which might
alleviate some pain in winding.  Problem is they only measure
at 3 ohms.  They are a very tough molded plastic round cylinder
shape with the end opposite the coil being closed, which can
be tapped for ease in mounting.  Somewhat lengthy at 8.14 cm
(3.2"),  diameter of the plastic is 3.51 cm (1.382").  The coil
business end is smaller in diameter at 3.46 cm (1.365") by
1.04 cm (.410") with about 24 rectangular wires wide by 6
layers deep.  The wire is unusual stuff for sure.  With the coil
diameter of 3.48cm (1.365") and the bottom diameter of the coil
being 3.2cm (1.230"), I'am guessing the mean circumference is
3.42cm (1.346").  The actual I.D. inside the plastic is 3.6 cm
(1.209").  They don't seem to vary more than + - .002".  The
precision wound coil is there.

I think the winding is contra terminology as the beginning and the
end meet in the same plane (upper end).  Anyway, with the above,
this would make the wire length some 492.48cm (193.9").

The surplus source can't seem to make up their mind about price
as they have not marked the item (probably acouple hundred
available), but over time I've paid $2 and $4 each, depending on
who's there at the time-ha.

Have made a number of home brew magnet assemblys using iron
washers and "wing" 2 pole, 1.27cm (.5") thick neodymium magnets,
which give a max gauss of some 14K, but with the iron and some
..26 cm (.1") gap, each side of the coil and no gaussmeter around,
the field is probably greatly reduced to a lesser fraction (guess) of
around 2-5k to the center pole.   Months back, I tried a 9 volt
battery to the coil and hand holding the coil....zip... like a solenoid
in both polaritys-ha. Yes,...the coil survived, but it got hot of
course.

Obviously the coil seems to dominate the rarity scale of things.
I don't know if it will work for the S-G, as I'am terrible at math
and electronics (my metric measurements maybe weird also).

I suppose the potential is here for a somewhat "standard" design??

Two pole magnets are around surplus sources, but they wildly
vary in size, thickness, price, quanity etc.   I've tried a variety
of ferrite, but nothing is big enough, and the stuff is fairly
impossible to work....thats why I went to sandwiching neos
between washers.  I've seen the same size neo sell from $1.25
each; on up to around $6.00 each....wow.....especially when
one may need 4 or more each assembly.

Anyway.....the coil is on the table so too speak.  Don't know
the manufacturer, but they seem to have been made in 87-88
from the white paint markings on the black plastic.

Am seeking your opinion.  Can forward a sample or two, if you
wish.  If they sound no good, then this can be the end here for
the coil.  My eyes aren't very good close up...so you may find
deviation from the figures above.

Who knows...they maybe the partial answer for your prospective
shorter length STM-8?  Well....partially....maybe.

I'am carrying on, and, with no mention of the electronics either.....

Meredith Lamb





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From: S-T Morrissey 
Subject: coils, magnets, and G
Date: Mon, 7 Sep 1998 22:32:56 -0500 (CDT)

Meredith,

The low resistance coils you describe sound interesting, but
the important consideration is what the motor constant might be
when you fit them to a magnet. And you are an expert at home-brewing
magnet assemblies, whereas I would buy a magnet, probably from
Edmund Sci., and try everything in sight to see if it would fit
as a coil former. ANd even though I can only see the #36 wire
with my glasses off, I would wind the coil to fit the magnet, 
using a spindle setup to support the coil and patiently winding 
every turn parallel and every layer flat to optimize the turns
density.  (As a grad student, I wound the poles of quadrupole
lenses for the cyclotron, where every turn had to be placed 
exactly, and even the dress of the leads had to be identical 
to maintain symmetry). I have wound 25 and 50 turn auxillary
coils above the speaker coil for the STMs.

But determining the approximate coil-magnet constant is necessary. For
a quick estimate, I tape the coil under the end of a ruler and
balance it with whatever (the salt shaker?) with a pen as a fulcrum
across a book. The magnet is resting on the table but under and 
carefully aligned inside the coil.  The setup is carefully balanced, 
then upset by placing a gram or ten on top of the coil. Then a 
controlled current (battery, variable resistor, and meter) thru the 
coil is used to rebalance the beam. It is very approximate
depending on the "quality" of your beam balance, but will quickly
help sort out the better magnet configurations, etc. And having
determined the G of the assembly, if you can figure the length
of the winding, the actual strength of the magnet can be determined.

But for the reduced size STM, I am holding out for a readily
available retail resource, rather than limited surplus finds. 
Actually, the size reduction (to less than 8" long) may require 
too many compromises to be acceptable (to picky me, of course). 
One of the problems is trying to keep the VRDT away from the main 
magnet.

Regards,
Sean-Thomas

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From: John Hernlund 
Subject: RE: Hall-effect sensors
Date: Tue, 08 Sep 1998 08:04:55 -0700 (MST)

On Sat, 5 Sep 1998, meredith lamb wrote:
> Current problems I see (perhaps too frequently), is because of its
> bridge nature; power supply fluctuations create spikes from
> household  draw on the line.  Batterys are thought entertained.
> Presently I use only doorbell wires from the upstairs amplifer; some
> shielded wire between can help noise reduction....along with a nice
> ground connection on the seismo sometime near in the future.

   I am seriously looking into a battery power supply for some other research
that I am working on, because for the sensitivity of our and definitely a hall
device assembly is strongly dependent on the noise from the amplifier.  The
only problem is that batteries run low eventually...  I was thinking of using
two banks of batteries connected to a switch that will charge one side while
the other is cranking and change over when they get low.  If I do explore this
option, I'll let you know how it works out and if there are any good switching
and charging methods available...

   I was also wondering how well a home-built hall device might work.  The
concept is simple, connect a low-noise circuit to a flat conductor (maybe a
square sheet of pure low resistance metal; Platinum comes to mind) and connect
two lead across the top and bottom of the sheet to measure the relative
voltage...  The rest is all amplification.  The whole thing would need to be
shielded of course.

******************************************************************************

			       John Hernlund
     		          E-mail: hernlund@.......
      WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/
		    http://www.public.asu.edu/~hernlund/

"It is easier to excuse an ignorant person who claims that theory is
unnecessary and dispensable in his supposed practice, than to excuse a
Sophist who concedes its value to the schools (as, perhaps, only a mental
exercise) but who at the same time maintains that matters are quite
different in practice- that as one leaves school to enter the world, one
will realize one has been pursuing empty ideals and philosophical dreams-
and, in a word, that what sounds good in theory is of no practical
use."
-Immanuel Kant, On the Proverb: That May be True in Theory, But Is of No
Practical Use

******************************************************************************


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From: meredith lamb 
Subject: RE: Hall-effect sensors
Date: Tue, 08 Sep 1998 11:10:27 -0600

John Hernlund,

OK on battery bank possibility.  Yes I'd be interested in any
eventual setup/charging resolution.  Sean-Thomas recommends
same age batterys as I recall from past email.  I would expect
some reasonably cheap auto variety, would be best, along with
a normal charger/s. (Wonder if one charger would be adequate,
using trickle charge?)

If you get into home-built hall experiments, that would also be
interesting to hear of your results.  Hmmm, I immediately wonder
what the results maybe of a larger sheet size might be, from the
environment?  Speculation.  Probably not cost possible.....
Never checked out the basic concept myself.  I would guess the
main magnetic susceptiblity is via the broad side, but maybe not.

Shielding the magnet/hall sensor that you mentioned, is also a
item which would likely help noise reduction.  It could not be
totally enclosed of course.  

Meredith Lamb



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From: meredith lamb 
Subject: Re: coils, magnets, and G
Date: Tue, 08 Sep 1998 11:54:19 -0600

meredith lamb wrote:

> >Sean-Thomas wrote:  One of the problems is trying to keep the VRDT
> away from the main magnet.

Sean-Thomas,

 In regard to possible vrdt shielding, this might be considered.
 I suppose reprinting this older email, may bring some protest,
 but according to Robert Lamb, the stuff is a mu-metal and can be
 used accordingly.  He had the stuff nuclear metal element tested
 and its real.  He has used the stuff for along time, and because
 of the foil like nature, as I remember, he says about 5 layers work
 pretty good. It would seem to be a good reprint what with STM-8
 consideration S-G sensor possible vrdt use, and even my Hall noise  
 problems considerations.

 This is a reprint from the email dated 4/10/98, Surplus store
 Mu-metal foil:

> meredith lamb wrote:
>
> > A possible source for mu-metal might be found in electronic
> > surplus stores.  These are canned donut shaped which were originally
> > used for donut choke etc. coils...i.e., ferrite predominates now.  In
> > Colorado I've seen them in 3 out of 4 surplus stores.  They seem to
> > be mostly orange, but sometimes black and mixed in with the ferrite
> > core stuff.  The tip off is that on one side, on the rim it has the
> > appearance of being like a grocery can lid edge.  Some are made
> > different, and can be pried open, or pulled apart.  Inside is
> > mu-metal rolls of foil, usually not too wide...varies ~ 1/4", but
> > they can usually be rolled off readily to whatever surface...and
> > glued...whatever.  The prices really run a wide range, from cheap to
> > fairly expensive...50 cents each on up to $3 each, depending on store.
> > These maybe leftovers From the 60's or so.  Diameters are ~ 1.25 to
> > 1.50" usually, but some are bigger.  I don't know how thick the foil
> > is...I've never got one.  For your deal, it may take several, and
> > hopefully you can get them cheap.  They are getting scarcer all the
> > time, and never seem to be in much quanity at all.  If it doen't
> > look like ferrite, check it out.
> >
> > Meredith Lamb


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From: John Hernlund 
Subject: RE: Hall-effect sensors
Date: Tue, 08 Sep 1998 11:04:56 -0700 (MST)

Here is a brief description of the Hall Effect:

As a current flows through a conductor the motion of the charge carriers
(electrons) are influenced by a magnetic field.  The force that moves the
electrons is at right angles to both the motion of the electrons themselves
and the magnetic field direction.  This means they are deflected upwards to
the top of the conductor or downwards to the bottom of the conductor,
depending on the direction of the current and/or magnetic field lines.  If
more electrons are moved in one direction than the other then the top and
bottom of the conductor will develop a relative electric charge, which is
measurable using a volt meter...



******************************************************************************

			       John Hernlund
     		          E-mail: hernlund@.......
      WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/
		    http://www.public.asu.edu/~hernlund/

"It is easier to excuse an ignorant person who claims that theory is
unnecessary and dispensable in his supposed practice, than to excuse a
Sophist who concedes its value to the schools (as, perhaps, only a mental
exercise) but who at the same time maintains that matters are quite
different in practice- that as one leaves school to enter the world, one
will realize one has been pursuing empty ideals and philosophical dreams-
and, in a word, that what sounds good in theory is of no practical
use."
-Immanuel Kant, On the Proverb: That May be True in Theory, But Is of No
Practical Use

******************************************************************************


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From: S-T Morrissey 
Subject: mu-metal
Date: Tue, 8 Sep 1998 17:56:10 -0500 (CDT)

Meredith,

I have looked into the availability of mu-metal, particulaly the
conical cylinders used to shield CRT tubes. A problem with mu-metal
is that it has to be annealed over a complex temperature profile
after it has been fabricated or re-worked. Any bending or cutting
destroys the grain properties of the alloy in the regions that are
restressed, possibly rendering it about as useful as a tin can.

I recently worked on some specifications for magnetic shielding of
1-hz geophones to be used in a very high sensitivity application.
The mu-metal cans were of 1/8" material, with welded bottoms and
a flanged cap, and cost about $200 ea. If we dropped one on the
concrete, it had to be sent back to be re-annealed, since the shock
in the earths' magnetic field would render it magnetic.

regards,
Sean-Thomas


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From: Jim Hannon 
Subject: Re: coils, magnets, and G
Date: Tue, 08 Sep 1998 19:26:53 -0500

On the subject of magnetic shielding. While looking for something to use
as the core for a ELF recieving coil I ran across this material 
http://www.allied.com/metglas/magnetic/2714a.htm The particular alloy
described in the web page has a perm of 1 million when properly
annealed. It comes in thin ribbons. I found one company that is making
toriods out of the suff. Still haven't found someplace to buy some of
the stuff. 
-- 
Jim Hannon
http://soli.inav.net/~jmhannon/
42,11.90N 91,39.26W
WB0TXL


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From: S-T Morrissey 
Subject: 0.01% battery power supply
Date: Tue, 8 Sep 1998 19:30:45 -0500 (CDT)

Re: magnetometer power supply:

A highly regulated battery operated supply is described in:

"A 50-Milliwatt Power Converter to Replace Mercury Batteries in 
Seismic Amplifier/VCO Systems", Bulletin of the Seismological
Society of America, Vol. 72, No. 2, pp671-674, April 1982.
by Sean-Thomas Morrissey.

The seismic amplifiers and telemetry VCOs were originally powered
by 4.05 volt mercury batteries that provided low noise for the
seismic amp and very well regulated voltage so the VCO (voltage 
controlled oscillator) frequency would not drift. When the Hg
batteries were no longer available, we developed this circuit to
"steal" a few milliamps from the large air-cell batteries that
powered the VHF transmitter, while still allowing a full two
years of operation from the 12 volt battery pack.

Its output is 4.05VDC, +- 0.01%, providing up to +- 4 milliamps.
This might not be enough for the magnetometer operating current.
It has a CMOS inverter, which we replace with a 1 watt unregulated
commercial inverter ($30) for higher output currents and voltages 
while still being able to regulate to 0.01%. The voltage reference 
is a LM136-2.5, a 20 ppm device with military specification (a 
LM285 can be used). Different output voltages are available by 
changing one resistor. 

The CMOS version  will operate at full load for at least a month 
from a 12-volt alkaline lantern battery.  The high current, +- 9 volt 
version is used in the STM feedback electronics, powered by a radio 
Shack 12 v, 500 ma power cube ($12).

For non-battery powered applications, there are linear regulators
like the LM317T and others that have been suggested that can 
provide 0.1% at 100 milliamps.

regards,
Sean-Thomas

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From: meredith lamb 
Subject: "Hall" down to your 1999 Radio Shack catalog
Date: Tue, 08 Sep 1998 20:32:43 -0600

According to Bob Lamb, Radio Shack in their 1999 catalog,
carrys a number of linear Hall devices now, including our
experimentally used Allegro/Sanken 3503 and 3515 devices
as seismic sensors.   The list they show is on page 194, upper
right.  Another linear there is the A3516EU, a 2.5m/g, which
we haven't tried.  The A3515EU is the most sensitive with
5.0m/g.  Prices seem to be competitive, with the 3515 at
$4.79 each plus shipping and handling.  If ordered they would
have to be purchased as a mail order item via a co-operating
Radio Shack store (not all do).  Only the ones I mentioned
are linear.  The 3503 does not have a chopper, whereas the
3515 & 3516 do (I'd call it assisted, as they do drift).

Another item immediately below the hall effect sensors is a
possibly interesting item.  A "Calibrated Hall-effect linear kit"
used for measuring magnetic flux densities.  They don't give the
range of the item, but it is likely for low flux fields like below
2K or so?  It does not say any other electronics is included,
nor even if a Hall device is included, but the Hall is inferred.
Only says it includes a "tool",reference curve & CD-ROM data book.
Wonder even if a schematic is included?  $59.99

Meredith Lamb


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From: "Al Allworth" 
Subject: RE: coils, magnets, and G
Date: Tue, 8 Sep 1998 21:45:51 -0700



> -----Original Message-----
> From: Jim Hannon [mailto:jmhannon@.........
> Sent: Tuesday, September 08, 1998 5:27 PM
> To: PSN-L Mailing List
> Subject: Re: coils, magnets, and G
>
>
> On the subject of magnetic shielding. While looking for something to use
> as the core for a ELF recieving coil I ran across this material
> http://www.allied.com/metglas/magnetic/2714a.htm The particular alloy


From Al Allworth

I have been saving some of the anti-theft strips but haven't explored their
properties
yet. According to the data sheet on the site they might be free samples of
the material
in question.


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From: Karl Cunningham 
Subject: Re: coils, magnets, and G
Date: Tue, 08 Sep 1998 23:09:31 -0700

Jim & the group --

We use metglas for shielding at work and have it in two varieties:  Strip
about 2" wide and about 0.001" thick, and 6-ply laminate (six 0.001" layers
of metglas, each separated by a layer of 0.0005" polyester).  The laminate
is much more effective as a shield, but about as malleable as a microscope
slide and about as difficult to cut.  It also is as sharp as glass when cut
and very hazardous to work with.  It can shatter into very small shards
which can fly into the air and can even be inhaled if one is not careful.

The strip is much more friendly to work with -- about like stainless steel
of the same thickness.  I think it suffers from the same annealing problem
as other mu-metal, though -- if you bend it, you have to anneal it to get
its shielding properties back.

I think we can spare a few pieces, and if a couple of people are interested
in playing with it I can mail a bit out.  Let me know.

-- Karl


At 07:26 PM 9/8/98 -0500, you wrote:
>On the subject of magnetic shielding. While looking for something to use
>as the core for a ELF recieving coil I ran across this material 
>http://www.allied.com/metglas/magnetic/2714a.htm The particular alloy
>described in the web page has a perm of 1 million when properly
>annealed. It comes in thin ribbons. I found one company that is making
>toriods out of the suff. Still haven't found someplace to buy some of
>the stuff. 


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From: "Francesco" 
Subject: LARGE QUAJKE IN ITLY
Date: Wed, 9 Sep 1998 15:21:11 +0200

11.38 UTC

MB 5.6

SOUTHERN ITALY

SOME MATERIAL DAMNAGES

Later, other us information

I.ES.N.  -  PSN ITALY
FRANCESCO NUCERA









11.38 UTC


 


MB 5.6


 


SOUTHERN ITALY


 


SOME MATERIAL DAMNAGES


 


Later, other us information


 


I.ES.N.  -  PSN ITALY


FRANCESCO NUCERA


From: "Francesco" 
Subject: ITALIAN QUAKE
Date: Wed, 9 Sep 1998 16:27:12 +0200

many material damnages
Some people iniured,
1 victmis, until now.

Someone had registered the event?

I.E.S.N.
Francesco nucera









many material damnages


Some people iniured,


1 victmis, until now.


 


Someone had registered the =
event?


 


I.E.S.N.


Francesco nucera


From: Canie Brooks 
Subject: Re: ITALIAN QUAKE
Date: Wed, 09 Sep 1998 07:47:19 -0700

At 04:27 PM 9/9/98 +0200, Francesco wrote: 
>
> many material damnages
> Some people iniured,
> 1 victmis, until now.
>  
> Someone had registered the event?


This was found at the site:
http://seismo.ethz.ch/redpuma/redpuma_ami_list.html
D a t e  Time (UTC)   Location  Dep Magni. T AGY R e g i o n
HHMM
 
09Sep1998 11:29:28.0 45.1N  10.6E 10 ML>4.2 A*SED NORTHERN ITALY           
1135
09Sep1998 11:28:05.3 40.5N  16.5E 10 No Mag M*SED SOUTHERN ITALY           
1341
09Sep1998 11:28:05.0 39.6N  15.6E  0 mb=5.2 M*MAD SOUTHERN ITALY           
1249
09Sep1998 11:28:00.4 40.0N  15.9E 33 MS=5.4 M*GSR SOUTHERN ITALY           
1249
09Sep1998 11:27:59.5 40.0N  16.0E 10 ML=5.3 M*EMS SOUTHERN ITALY           
1241
09Sep1998 11:27:59.0 39.6N  18.0E 10 No Mag M*LED SOUTHERN ITALY           
1233
09Sep1998 11:27:15.6 37.6N  19.0E 10 ML=5.4 A*ING IONIAN SEA               
1142



>
>  
> I.E.S.N.
> Francesco nucera




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From: "Charles R. Patton" 
Subject: Re: Pivot point
Date: Wed, 09 Sep 1998 12:29:35 -0700

With all the talk of pivots, I would like to toss out a question.  Has
anyone ever experimented with a "Rollamite" type bearing?  It would seem
to me that it would solve several needs simultaneously.

1. It is a flexure bearing that has a rolling contact =96 but by design i=
t
does not have any sliding friction.
2. It=92s position and "axis of rotation" are very well defined.  This
should address one problem with flexure pivots in that the point of
revolution can move or is somewhat undefined as has been mentioned by
Sean-Thomas.

I=92ve played with them for a project and they can be very low friction,
similar to the ball bearing.  But they are dependent on flexure, just as
flexure bearings are so the hysteresis in shim stock will show up,
however they are balanced, so no additional force will appear as they
roll (i.e. they do not act like a spring unlike the flexure bearing
which can have significant spring rates.)

You can look at  patent "4438983 : Low friction pivot " at=20
http://www.patents.ibm.com/patquery.html
which shows a slightly more complex form of the basic Rollamite
bearing.  I=92ll try and describe it in words=20

Take two clylinders, A & B, and place side-by-side in rolling contact
(not end-to-end). And stand them on end on a flat surface (a table for
instance).I.e., a salt & pepper shaker set  sitting side-by-side.  Now
take a ribbon (srping steel band or music wire), tape it to A at a point
away from the line of contact between A & B and 1/3 of the way up the
cylinder.  Start wrapping it CW around A, just like Scotch tape is on
the spool) and pass between the line of contact of  A & B , but instead
of continuing on A, start wrapping CCW on B and go a bit further and cut
the ribbon and tape it to B.  At this point you have an "S" shaped
ribbon (when viewed from above) of one half turn on each cylinder.  Now
1/3 of the way from the top repeat the whole procedure above.  Be sure
that when you tape the final point that the ribbons are taut and the
cylinders are parallel.  Now the magic.  Do one more ribbon half way up
(between the other two ribbons) but start the wrap in the opposite
direction (CCW).  When you reach the end, pull the ribbon tight and tape
it down.  You have just made the basic Rollamite bearing of very low
friction, far superior to any roller bearing of equivalent size.  Actual
construction could be with drill blanks and music wire or steel shim
stock.  For a simple kinematic design, usedtwo Rollamites in crossed
configuration  (a universal joint) at the pivot point.
The results would be a pivot point that will not slip, has a controlled
axis of rotation (i.e. the period will not change because of change in
strength of the flexure point.)

Charles R. Patton
charles.r.patton@........

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From: Karl Cunningham 
Subject: Re: Pivot point
Date: Wed, 09 Sep 1998 13:06:45 -0700

Charles --

Excellent description!  I've wondered about this type of thing instead of
pivots, but have not experimented.  Has anyone tried this?

-- Karl
karlc@.......

At 12:29 PM 9/9/98 -0700, you wrote:
>With all the talk of pivots, I would like to toss out a question.  Has
>anyone ever experimented with a "Rollamite" type bearing?  It would seem
>to me that it would solve several needs simultaneously.
[snip]


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From: "Warren Shedrick" 
Subject: OP27 OP227 Op Amp
Date: Wed, 9 Sep 1998 16:50:45 -0700

Several weeks ago, someone mentioned that one of the sites on the 
Seismic network contained a schematic for a high gain amplifier using 
a OP27 or OP227 opamp that would be suitable for use with a 
seismometer. Does anyone know where this site is?

Thank you 

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From: Jim Hannon 
Subject: Re: coils, magnets, and G
Date: Wed, 09 Sep 1998 20:11:39 -0500

Karl Cunningham wrote:
> 
> Jim & the group --
> 
> We use metglas for shielding at work and have it in two varieties:  Strip
> about 2" wide and about 0.001" thick, and 6-ply laminate (six 0.001" layers
> of metglas, each separated by a layer of 0.0005" polyester).  The laminate
> is much more effective as a shield, but about as malleable as a microscope
> slide and about as difficult to cut.  It also is as sharp as glass when cut
> and very hazardous to work with.  It can shatter into very small shards
> which can fly into the air and can even be inhaled if one is not careful.
> 
> The strip is much more friendly to work with -- about like stainless steel
> of the same thickness.  I think it suffers from the same annealing problem
> as other mu-metal, though -- if you bend it, you have to anneal it to get
> its shielding properties back.
> 
> I think we can spare a few pieces, and if a couple of people are interested
> in playing with it I can mail a bit out.  Let me know.
> 
> -- Karl

Karl, 
Thanks for the offer, but if I follow through on the project I will need
quit a bit of the stuff. 

 BTW The 2417 alloy should make a great flux gate magnetometer as it
saturates very easily.

-- 
Jim Hannon
http://soli.inav.net/~jmhannon/
42,11.90N 91,39.26W
WB0TXL


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From: meredith lamb 
Subject: Re: OP27 OP227 Op Amp
Date: Thu, 10 Sep 1998 11:03:28 -0600

Warren Shedrick wrote:

> Several weeks ago, someone mentioned that one of the sites on the
> Seismic network contained a schematic for a high gain amplifier using
> a OP27 or OP227 opamp that would be suitable for use with a
> seismometer. Does anyone know where this site is?
>
> Thank you
>

Warren,

Am fairly sure there is no circuit per say, devoted to that op amp.
I think the discussion evolved around a general discussion of
worthy op amps which evolved around a possible replacement
question (at the time) of the LM308, used in the STM-8, and,
for use in any prospective circuits.

Meredith Lamb


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From: "David A. Nelson" 
Subject: Re: OP27 OP227 Op Amp
Date: Fri, 11 Sep 1998 09:34:24 +1200

At 11:03 AM 9/10/98 -0600, you wrote:
>Warren Shedrick wrote:
>> Several weeks ago, someone mentioned that one of the sites on the
>> Seismic network contained a schematic for a high gain amplifier using
>> a OP27 or OP227 opamp that would be suitable for use with a
>> seismometer. Does anyone know where this site is?
>> Thank you
>Warren,

 Yes Warren,
                      U are correct,  its on my PSN pages......

 http://psn.quake.net/dave/g_phones.htm

 this is the section  describing my station setup


 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


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From: Doug Crice 
Subject: Re: OP27 OP227 Op Amp
Date: Thu, 10 Sep 1998 14:53:53 -0700

Hello Dave,

I admire your ingenuity and appreciate your effort, but I can't help
kibitzing your design.

On the preamp, it would probably be more appropriate to use
non-polarized film 1 uFd capacitors in the high cut filters instead of
electrolytics.  These are readily available in most surplus stores at
modest cost.

The second TL071 is wired as a non-inverting amplifier, which means that
its input impedence is many megohms.  You could put a good-sized
capacitor in the input and filter out any minor DC offset from the
preamp and then you don't need the offset adjust circuit on the TL071.
(At least for the 4.5 Hz geophones, probably not for the long-period
sensor).
-- 
Doug Crice   
David A. Nelson wrote:
> 
> At 11:03 AM 9/10/98 -0600, you wrote:
> >Warren Shedrick wrote:
> >> Several weeks ago, someone mentioned that one of the sites on the
> >> Seismic network contained a schematic for a high gain amplifier using
> >> a OP27 or OP227 opamp that would be suitable for use with a
> >> seismometer. Does anyone know where this site is?
> >> Thank you
> >Warren,
> 
>  Yes Warren,
>                       U are correct,  its on my PSN pages......
> 
>  http://psn.quake.net/dave/g_phones.htm
> 
>  this is the section  describing my station setup
> 
>  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)
> 
> To leave this list email listserver@............. with the body of the
> message: leave PSN-L


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From: S-T Morrissey 
Subject: seismic amplifier
Date: Thu, 10 Sep 1998 19:02:17 -0500 (CDT)

Re. micropower seismic amplifier:

Since 1981 we have been using a micropower seismic amplifier
for all the telemetry stations. It is based on the LM4250CN
micropower amplifier. It uses four amplifiers, with the total
current drain of 80 microamps at +-4.05 volts. The first two
amps are for DC gains of 18 to 54 db and 6 to 36 db. The
second two amps are a 4-pole low pass filter at 20 hz. The
first and second gain stages are AC coupled at a 60-second corner
to remove the DC offset, and the output is similarly AC coupled 
for input to the VCO. The noise referred to the input at 60db 
(gain of 1000) is 1 microvolt. For most stations using the L4-C 
seismometer (pre-scaled for 100v/m/s output) the gains range 
from 60 to 72 db. The additional gain available up to 90 db 
(gain of 31 600) is useful for smaller geophones.

The schematic is posted on the PSN info page at:
http://www.eas.slu.edu/People/STMorrissey/index.html
The original is an old pencil drawing, so the quality is
not very good. If you remember what a SASE is, I can mail
a copy, along with the circuit board artwork.

For use as an isolated amplifier, (installed in the borehole
near the seismometer or geophone), photo-lithium batteries 
can be used. A battery pack of 6 of the the AA size, configured
for +,- 4.8 volts, will provide 80 microamps for 30 months or more.
The AA size costs about $6 per pair. Larger lithiums will last
for years, or the shelf life: 80 microamps is about the level 
of the internal leakage.

A question was raised about using the low noise OP27: it is specified for
a supply current of 4.7 milliamps, which is not compatible with
long term battery operation. The OP184 is similarly low noise, but is
specified for 30 microamps; the OP181/186 are even lower power at 
4 microamps, but have considerable voltage noise. The MC1776 is
the Motorola replacement for the LM4250, with a noise level of
less than 6 nanovolts/hz.

Regards,
Sean-Thomas

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From: Steve Hammond 
Subject: Re: OP27 OP227 Op Amp
Date: Thu, 10 Sep 1998 17:16:58 -0700

The older PSN member have used the OP-27 a lot. When Larry built his amp
board, it was so nice we dropped the design from the WEB pages. This is
the only copy I have online at the moment, it is from the old PSN BBS in
San Jose, so it will have to do until I have more time. I put AMP2_1.GIF
on the PSN WEB site in San Jose at.
http://pw2.netcom.com/~shammon1/equip.htm
If you can't download the image from the web page, drop me a line and
after I get my scanner software reloaded I'll make a copy of Pete Rowes
orginal drawing and send it to you.

Sorry for the delay.
Regards, Steve Hammond   PSN San Jose



Warren Shedrick wrote:
> 
> Several weeks ago, someone mentioned that one of the sites on the
> Seismic network contained a schematic for a high gain amplifier using
> a OP27 or OP227 opamp that would be suitable for use with a
> seismometer. Does anyone know where this site is?
> 
> Thank you
> 
> _____________________________________________________________________
> 
> Public Seismic Network Mailing List (PSN-L)
> 
> To leave this list email listserver@............. with the body of the
> message: leave PSN-L

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From: Steve Hammond 
Subject: Re: OP27 OP227 Op Amp
Date: Thu, 10 Sep 1998 17:55:11 -0700

A few points on the last post.
(1) An OP-27 can be sub'ed for the LF353.
(2) If you try to use OP-37's, remember that
they must have a min closed loop gain >4 (check the tech sheet).
(3) The one pole filter in the drawing 1M rest /.015 cap following the
coil driver op-27 should be labeled 1M / 1uf cap (not .015uf)
(4) you may want to play with this filter. It should rolloff at about
10hrz in the city were there is noise. What it is doing is cutting off
as much noise as it can before the noise is amplified by the following
gain stages.
Regards, Steve Hammond
 

Steve Hammond wrote:
> 
> --------------------------------------------------------------------------
> Your following message has been delivered to the 262 members of
>   the list psn-l@............. at 18:18:30 on 10 Sep 1998.
> --------------------------------------------------------------------------
> 
> The older PSN member have used the OP-27 a lot. When Larry built his amp
> board, it was so nice we dropped the design from the WEB pages. This is
> the only copy I have online at the moment, it is from the old PSN BBS in
> San Jose, so it will have to do until I have more time. I put AMP2_1.GIF
> on the PSN WEB site in San Jose at.
> http://pw2.netcom.com/~shammon1/equip.htm
> If you can't download the image from the web page, drop me a line and
> after I get my scanner software reloaded I'll make a copy of Pete Rowes
> orginal drawing and send it to you.
> 
> Sorry for the delay.
> Regards, Steve Hammond   PSN San Jose
> 
> Warren Shedrick wrote:
> >
> > Several weeks ago, someone mentioned that one of the sites on the
> > Seismic network contained a schematic for a high gain amplifier using
> > a OP27 or OP227 opamp that would be suitable for use with a
> > seismometer. Does anyone know where this site is?
> >
> > Thank you
> >
> > _____________________________________________________________________
> >
> > 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

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From: George Harris 
Subject: Re: Pivot point
Date: Wed, 09 Sep 1998 20:17:04 +0000

Karl Cunningham wrote:
> 
> Charles --
> 
> Excellent description!  I've wondered about this type of thing instead of
> pivots, but have not experimented.  Has anyone tried this?
> 
> -- Karl
> karlc@.......
> 
> At 12:29 PM 9/9/98 -0700, you wrote:
> >With all the talk of pivots, I would like to toss out a question.  Has
> >anyone ever experimented with a "Rollamite" type bearing?  It would seem
> >to me that it would solve several needs simultaneously.
> [snip]

This is the type of pivot which I have been using for a couple years
in both horizontal and vertical experimental models.  I highly 
recommend it.  It is friction free, and has very low spring constant
when constructed correctly.  It is similar to what is known as a 
crossed flexure pivot.  Using it, very small seismos can be made with
long periods.  

The basic principle in making such a pivot is to orient it so that both
of the flexure elements (which should cross at an angle near 90 degrees)
are in tension.  The best material is very thin shim stock. Phosphor
bronze or berrylium copper are best though steel is acceptable if it
does not interfere with magnetics.  An alternative for the small units
is to use sheet mylar.  In either case, the thin material should be
clamped to a smooth curve to prevent sudden bends at the flexure point.

Recently, I have completed a model of a vertical unit which is 
about ten inches long with the mass being the feedback coil.  The
unit can be adjusted to periods of a few seconds.  The moving element
is in the shape of "T" with the coil on the long leg.  Each of the 
arms of the T has a crossed flexure to the base.  The mass is supported
by a horizontal wire above the T (the T is lying flat) which is
attached to a cantilever spring.  By properly adjusting the height of
the wire and it's tension, the period can be adjusted from very 
short to the point of instability.

I don't have the the means of taking photos and putting them on the
web.  However, I have just moved to the SF bay area, and I would
be glad to bring the unit to somone who can take a picture and put it
on their site.  Send a message to me if there is interest.

George Harris - Benicia, CA


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Public Seismic Network Mailing List (PSN-L)


From: Gregory Bajuk 
Subject: Re: Pivot point
Date: Fri, 11 Sep 1998 12:09:05 -0700 (PDT)

I was just looking at the inside of an old 30 meg hard drive and noticed
that the arm which holds the read/write heads is positioned by a 
cylindrical pivot type hinge attached to the stepper motor.  Is this the
type of pivot point you are describing?

Greg Bajuk

On Wed, 9 Sep 1998, George Harris wrote:

> Karl Cunningham wrote:
> > 
> > Charles --
> > 
> > Excellent description!  I've wondered about this type of thing instead of
> > pivots, but have not experimented.  Has anyone tried this?
> > 
> > -- Karl
> > karlc@.......
> > 
> > At 12:29 PM 9/9/98 -0700, you wrote:
> > >With all the talk of pivots, I would like to toss out a question.  Has
> > >anyone ever experimented with a "Rollamite" type bearing?  It would seem
> > >to me that it would solve several needs simultaneously.
> > [snip]
> 
> This is the type of pivot which I have been using for a couple years
> in both horizontal and vertical experimental models.  I highly 
> recommend it.  It is friction free, and has very low spring constant
> when constructed correctly.  It is similar to what is known as a 
> crossed flexure pivot.  Using it, very small seismos can be made with
> long periods.  
> 
> The basic principle in making such a pivot is to orient it so that both
> of the flexure elements (which should cross at an angle near 90 degrees)
> are in tension.  The best material is very thin shim stock. Phosphor
> bronze or berrylium copper are best though steel is acceptable if it
> does not interfere with magnetics.  An alternative for the small units
> is to use sheet mylar.  In either case, the thin material should be
> clamped to a smooth curve to prevent sudden bends at the flexure point.
> 
> Recently, I have completed a model of a vertical unit which is 
> about ten inches long with the mass being the feedback coil.  The
> unit can be adjusted to periods of a few seconds.  The moving element
> is in the shape of "T" with the coil on the long leg.  Each of the 
> arms of the T has a crossed flexure to the base.  The mass is supported
> by a horizontal wire above the T (the T is lying flat) which is
> attached to a cantilever spring.  By properly adjusting the height of
> the wire and it's tension, the period can be adjusted from very 
> short to the point of instability.
> 
> I don't have the the means of taking photos and putting them on the
> web.  However, I have just moved to the SF bay area, and I would
> be glad to bring the unit to somone who can take a picture and put it
> on their site.  Send a message to me if there is interest.
> 
> George Harris - Benicia, 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: S-T Morrissey 
Subject: flexure hinges
Date: Fri, 11 Sep 1998 20:38:02 -0500 (CDT)

Some historical info:

Crossed flexure hinges have been used on various seismometers
since the '40s, and have often been called the "Press-Ewing" 
suspension.  They are used on both vertical and horizontal sensors,
but are more complex on the latter since the lower suspension has 
to be mounted behind the axis of rotation so it is under tension,
while the upper flexures are in front of the axis. The
crossed flexure will not work with any significant amount of
compression. Even when they are used on vertical sensors with
large angled springs above the boom, as on the large Sprengnether
S5000, they are mounted behind the axis of rotation.

A variation that is closer to the "rolomite" design is seen on
the large Johnson-Matheson 0.8 second vertical of 1960, where
a "cardan" hinge is used on both ends of the spring cantilevers.
This uses a single bronze strip with the wider center strap folded 
back thru the narrower outer straps and clamped only on one side.
From the end it forms a figure-8 pattern. However, unlike the "rolomite",
there is no physical contact between the two supporting shafts; this
would probably add significant micro-positioning and thermal noise. 
(This seis had a fatal design flaw in that the coil was fixed to the
base and the magnet was the moving mass).

For the past decade the crossed flexures have been assembled inside
a pair of small parallel rings that are easily installed on the seismometer.
These "bendix" hinges are widely used in the current broadband designs.
They can be very compact (less than 1/8" diameter) and are made from pretty
exotic metals. An individual flexure may cost more than $100 though.

I have used the crossed flexure hinge in both the vertical and
horizontal designs of the STM seismometer. It is especially necessary
because it provides very precise control of the boom motion, which is
necessary because of the very close clearance of the coil in the magnet.
There is a (poor) photo of the horizontal prototype on the web site
(http://www.eas.slu.edu/People/STMorrissey/index.html)
showing the upper hinge pulling to the left (toward the boom) and
the lower pulling to the right,

Regards,
Sean-Thomas

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Public Seismic Network Mailing List (PSN-L)


From: Brian Chesire 
Subject: Re: flexure hinges
Date: Sun, 06 Sep 1998 02:34:48 -0700

I remember the Bendix (now Lucas) crossed flexures were quite expensive.
I just found another source at www.c-flex.com. No Idea of the price but
at least there seems to be one other manufacturer.

Brian Chesire

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Public Seismic Network Mailing List (PSN-L)


From: Bill Scolnik 
Subject: Shortt slave run
Date: Sun, 13 Sep 1998 19:23:04 -0400


Bob,

Here is last weeks run of the Fedchenko. As you can see, there still is
that peculiar 24 hour variation. This is a chart of the rate.

Bill
1005
 1.00000067493339	 4.836089E-07
 0	 1
 1	 2
 4	09-06-1998
 1	 8/29/98
 1	7:46:48 PM
 1	7:56:48 PM
 .999999961666667	8:06:48 PM
 1.00000001	8:16:48 PM
 1.00000009208333	8:26:48 PM
 1.00000005833333	8:36:48 PM
 1.00000006138889	8:46:48 PM
 1.00000006119048	8:56:48 PM
 1.00000004604167	9:06:48 PM
 1.00000007	9:16:48 PM
 1.00000007366667	9:26:48 PM
 1.00000009333333	9:36:48 PM
 1.00000012116667	9:46:48 PM
 1.000000164	9:56:48 PM
 1.000000155	10:06:48 PM
 1.00000021316667	10:16:48 PM
 1.000000262	10:26:48 PM
 1.00000027916667	10:36:48 PM
 1.000000319	10:46:48 PM
 1.00000034333333	10:56:48 PM
 1.00000037637454	11:06:50 PM
 1.00000038287238	11:16:50 PM
 1.00000039003665	11:26:50 PM
 1.00000037637454	11:36:50 PM
 1.00000038837054	11:46:50 PM
 1.00000037937354	11:56:50 PM
 1.00000034905032	12:06:50 AM
 1.00000035971343	12:16:50 AM
 1.00000037037654	12:26:50 AM
 1.00000035971343	12:36:50 AM
 1.000000322	12:46:50 AM
 1.00000033733333	12:56:50 AM
 1.00000034383333	1:06:50 AM
 1.00000034633333	1:16:50 AM
 1.00000033733333	1:26:50 AM
 1.00000032966667	1:36:50 AM
 1.00000035166667	1:46:50 AM
 1.00000036533333	1:56:50 AM
 1.00000037733333	2:06:50 AM
 1.000000394	2:16:50 AM
 1.000000442	2:26:50 AM
 1.00000042783333	2:36:50 AM
 1.00000043383333	2:46:50 AM
 1.000000442	2:56:50 AM
 1.00000046516667	3:06:50 AM
 1.00000048783333	3:16:50 AM
 1.00000048116667	3:26:50 AM
 1.00000048716667	3:36:50 AM
 1.00000048716667	3:46:50 AM
 1.00000043366667	3:56:50 AM
 1.00000042166667	4:06:50 AM
 1.00000043366667	4:16:50 AM
 1.00000044183333	4:26:50 AM
 1.0000004555	4:36:50 AM
 1.00000043366667	4:46:50 AM
 1.00000042166667	4:56:50 AM
 1.000000417	5:06:50 AM
 1.000000408	5:16:50 AM
 1.00000039133333	5:26:50 AM
 1.000000399	5:36:50 AM
 1.00000039383333	5:46:50 AM
 1.00000039433333	5:56:50 AM
 1.0000003885	6:06:50 AM
 1.00000037016667	6:16:50 AM
 1.00000037483333	6:26:50 AM
 1.00000036366667	6:36:50 AM
 1.00000036366667	6:46:50 AM
 1.000000341	6:56:50 AM
 1.00000033283333	7:06:50 AM
 1.00000036116667	7:16:50 AM
 1.00000035766667	7:26:50 AM
 1.000000335	7:36:50 AM
 1.0000003185	7:46:50 AM
 1.00000031716667	7:56:50 AM
 1.00000032316667	8:06:50 AM
 1.00000032966667	8:16:50 AM
 1.00000036516667	8:26:50 AM
 1.000000366	8:36:50 AM
 1.00000036516667	8:46:50 AM
 1.000000363	8:56:50 AM
 1.0000003605	9:06:50 AM
 1.00000038316667	9:16:50 AM
 1.00000038483333	9:26:50 AM
 1.0000003665	9:36:50 AM
 1.0000003575	9:46:50 AM
 1.00000037116667	9:56:50 AM
 1.00000032666667	10:06:50 AM
 1.0000003575	10:16:50 AM
 1.0000003725	10:26:50 AM
 1.00000039083333	10:36:50 AM
 1.00000036	10:46:50 AM
 1.00000034333333	10:56:50 AM
 1.00000034333333	11:06:50 AM
 1.00000031716667	11:16:50 AM
 1.00000032316667	11:26:50 AM
 1.0000003125	11:36:50 AM
 1.00000027566667	11:46:50 AM
 1.00000023116667	11:56:50 AM
 1.00000018533333	12:06:50 PM
 1.00000013833333	12:16:50 PM
 1.000000161	12:26:50 PM
 1.00000012416667	12:36:50 PM
 1.0000001105	12:46:50 PM
 1.00000013316667	12:56:50 PM
 1.00000007066667	1:06:50 PM
 1.00000003083333	1:16:50 PM
 1.00000003683333	1:26:50 PM
 1.00000001716667	1:36:50 PM
 1.00000001716667	1:46:50 PM
 1.000000003	1:56:50 PM
 .9999999465	2:06:50 PM
 .999999952	2:16:50 PM
 .999999945184938	2:26:52 PM
 .999999965344885	2:36:52 PM
 .999999991002999	2:46:52 PM
 1.00000000466511	2:56:52 PM
 1.00000001882706	3:06:52 PM
 1.00000038937021	3:16:52 PM
 1.00000039536821	3:26:52 PM
 1.00000041552816	3:36:52 PM
 1.00000040736421	3:46:52 PM
 1.00000040353216	3:56:52 PM
 1.00000025133333	4:06:52 PM
 1.0000001575	4:16:52 PM
 1.00000017166667	4:26:52 PM
 1.00000006166667	4:36:52 PM
 1.00000007316667	4:46:52 PM
 .99999975	4:56:52 PM
 .9999996905	5:06:52 PM
 .999999735833333	5:16:52 PM
 .999999822333333	5:26:52 PM
 .999999832666667	5:36:52 PM
 .999999978166667	5:46:52 PM
 1.00000001716667	5:56:52 PM
 1.00000003683333	6:06:52 PM
 1.0000001605	6:16:52 PM
 1.0000001105	6:26:52 PM
 1.000000101	6:36:52 PM
 1.000000354	6:46:52 PM
 1.00000028683333	6:56:52 PM
 1.000000259	7:06:52 PM
 1.00000028083333	7:16:52 PM
 1.00000033433333	7:26:52 PM
 1.00000038783333	7:36:52 PM
 1.00000038016667	7:46:52 PM
 1.00000032666667	7:56:52 PM
 1.000000354	8:06:52 PM
 1.0000003665	8:16:52 PM
 1.00000017166667	8:26:52 PM
 1.00000018533333	8:36:52 PM
 1.0000001965	8:46:52 PM
 1.0000001515	8:56:52 PM
 1.00000010616667	9:06:52 PM
 1.00000007366667	9:16:52 PM
 1.00000005816667	9:26:52 PM
 1.00000008133333	9:36:52 PM
 1.00000006166667	9:46:52 PM
 1	9:56:52 PM
 .999999983333333	10:06:52 PM
 .999999969666667	10:16:52 PM
 .999999935833333	10:26:52 PM
 .9999999435	10:36:52 PM
 .999999941333333	10:46:52 PM
 .9999999015	10:56:52 PM
 .999999874166667	11:06:52 PM
 .999999884833333	11:16:52 PM
 .999999883166667	11:26:52 PM
 .999999890833333	11:36:52 PM
 .999999869	11:46:52 PM
 .999999826166667	11:56:52 PM
 .999999798333333	12:06:52 AM
 .9999998125	12:16:52 AM
 .9999997975	12:26:52 AM
 .999999817666667	12:36:52 AM
 .999999834333333	12:46:52 AM
 .999999834333333	12:56:52 AM
 .999999855666667	1:06:52 AM
 .999999906666667	1:16:52 AM
 .9999999465	1:26:52 AM
 1.00000002783333	1:36:52 AM
 1.00000007833333	1:46:52 AM
 1.0000000985	1:56:52 AM
 1.00000013833333	2:06:52 AM
 1.000000161	2:16:52 AM
 1.00000016866667	2:26:52 AM
 1.00000018883333	2:36:52 AM
 1.00000020083333	2:46:52 AM
 1.00000019343552	2:56:54 AM
 1.00000021309563	3:06:54 AM
 1.00000021009663	3:16:54 AM
 1.00000024091969	3:26:54 AM
 1.00000025758081	3:36:54 AM
 1.00000025291569	3:46:54 AM
 1.00000027724092	3:56:54 AM
 1.00000029740087	4:06:54 AM
 1.00000032305898	4:16:54 AM
 1.00000035304898	4:26:54 AM
 1.000000363	4:36:54 AM
 1.00000038016667	4:46:54 AM
 1.00000039383333	4:56:54 AM
 1.00000039433333	5:06:54 AM
 1.00000039383333	5:16:54 AM
 1.0000004105	5:26:54 AM
 1.00000043883333	5:36:54 AM
 1.00000043666667	5:46:54 AM
 1.000000405	5:56:54 AM
 1.0000004225	6:06:54 AM
 1.00000043666667	6:16:54 AM
 1.0000004495	6:26:54 AM
 1.00000045083333	6:36:54 AM
 1.000000467	6:46:54 AM
 1.00000045083333	6:56:54 AM
 1.00000045115038	7:06:52 AM
 1.00000041730577	7:16:52 AM
 1.00000042914305	7:26:52 AM
 1.00000048099366	7:36:52 AM
 1.00000049983328	7:46:52 AM
 1.00000047199066	7:56:52 AM
 1.00000049766589	8:06:52 AM
 1.00000050833611	8:16:52 AM
 1.00000048566189	8:26:52 AM
 1.00000049166389	8:36:52 AM
 1.00000053583333	8:46:52 AM
 1.0000005525	8:56:52 AM
 1.00000052866667	9:06:52 AM
 1.000000515	9:16:52 AM
 1.00000050083333	9:26:52 AM
 1.00000057366667	9:36:52 AM
 1.00000060233333	9:46:52 AM
 1.0000006105	9:56:52 AM
 1.00000064816667	10:06:52 AM
 1.000000673	10:16:52 AM
 1.00000063616667	10:26:52 AM
 1.00000068366667	10:36:52 AM
 1.00000075433333	10:46:52 AM
 1.00000078466667	10:56:52 AM
 1.00000080373209	11:06:54 AM
 1.00000082122626	11:16:54 AM
 1.00000080923026	11:26:54 AM
 1.00000080923026	11:36:54 AM
 1.0000008263912	11:46:54 AM
 1.00000087637454	11:56:54 AM
 1.0000009041986	12:06:54 PM
 1.00000087520826	12:16:54 PM
 1.00000088887038	12:26:54 PM
 1.00000087987338	12:36:54 PM
 1.00000090066667	12:46:54 PM
 1.00000090283333	12:56:54 PM
 1.00000090333333	1:06:54 PM
 1.00000089216667	1:16:54 PM
 1.0000008725	1:26:54 PM
 1.000000825	1:36:54 PM
 1.000000828	1:46:54 PM
 1.0000008095	1:56:54 PM
 1.0000008185	2:06:54 PM
 1.00000079116667	2:16:54 PM
 1.00000078216667	2:26:54 PM
 1.0000007205	2:36:54 PM
 1.00000069566667	2:46:54 PM
 1.000000676	2:56:54 PM
 1.00000070333333	3:06:54 PM
 1.00000063016667	3:16:54 PM
 1.00000060833333	3:26:54 PM
 1.0000005715	3:36:54 PM
 1.00000048466667	3:46:54 PM
 1.000000464	3:56:54 PM
 1.00000038616667	4:06:54 PM
 1.0000003605	4:16:54 PM
 1.0000002975	4:26:54 PM
 1.00000026666667	4:36:54 PM
 1.00000017166667	4:46:54 PM
 1.0000001605	4:56:54 PM
 1.00000006716667	5:06:54 PM
 1.00000002016667	5:16:54 PM
 1.000000003	5:26:54 PM
 .9999999465	5:36:54 PM
 .9999999405	5:46:54 PM
 .9999998955	5:56:54 PM
 .999999854	6:06:54 PM
 .999999843333333	6:16:54 PM
 .999999774833333	6:26:54 PM
 .999999819333333	6:36:54 PM
 .999999828333333	6:46:54 PM
 .999999831333333	6:56:54 PM
 .999999814166667	7:06:54 PM
 .999999825333333	7:16:54 PM
 .9999997945	7:26:54 PM
 .999999755166667	7:36:54 PM
 .999999768833333	7:46:54 PM
 .999999751666667	7:56:54 PM
 .999999780833333	8:06:54 PM
 .999999730333333	8:16:54 PM
 .999999730333333	8:26:54 PM
 .999999732	8:36:54 PM
 .999999712333333	8:46:54 PM
 .999999721333333	8:56:54 PM
 .999999744	9:06:54 PM
 .999999811166667	9:16:54 PM
 .9999998455	9:26:54 PM
 .9999998455	9:36:54 PM
 .999999875833333	9:46:54 PM
 .9999998985	9:56:54 PM
 .999999923333333	10:06:54 PM
 .999999972166667	10:16:54 PM
 1	10:26:54 PM
 1.00000001666667	10:36:54 PM
 1	10:46:54 PM
 1.000000012	10:56:54 PM
 .999999982833333	11:06:54 PM
 1.00000001966667	11:16:54 PM
 1.0000000475	11:26:54 PM
 1.00000008733333	11:36:54 PM
 1.00000009033333	11:46:54 PM
 1.00000009033333	11:56:54 PM
 1.00000013016667	12:06:54 AM
 1.000000155	12:16:54 AM
 1.0000002025	12:26:54 AM
 1.0000002085	12:36:54 AM
 1.00000025433333	12:46:54 AM
 1.00000027916667	12:56:54 AM
 1.000000256	1:06:54 AM
 1.00000028683333	1:16:54 AM
 1.00000031466667	1:26:54 AM
 1.00000032016667	1:36:54 AM
 1.00000033433333	1:46:54 AM
 1.00000032916667	1:56:54 AM
 1.00000036733333	2:06:54 AM
 1.000000372	2:16:54 AM
 1.0000004105	2:26:54 AM
 1.00000044733333	2:36:54 AM
 1.00000050516667	2:46:54 AM
 1.00000050733333	2:56:54 AM
 1.00000055616667	3:06:54 AM
 1.00000061783333	3:16:54 AM
 1.000000631	3:26:54 AM
 1.000000679	3:36:54 AM
 1.00000068366667	3:46:54 AM
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 .9999998895	10:27:17 PM
 .999999899	10:37:17 PM
 .999999905	10:47:17 PM
 .999999902	10:57:17 PM
 .999999906666667	11:07:17 PM
 .999999906666667	11:17:17 PM
 .999999929333333	11:27:17 PM
 .9999999495	11:37:17 PM
 1.00000001666667	11:47:17 PM
 1.00000007916667	11:57:17 PM
 1.00000004583333	12:07:17 AM
 1.00000007533333	12:17:17 AM
 1.00000008433333	12:27:17 AM
 1.00000011	12:37:17 AM
 1.00000011766667	12:47:17 AM
 1.00000013483333	12:57:17 AM
 1.00000012416667	1:07:17 AM
 1.00000014383333	1:17:17 AM
 1.00000014733333	1:27:17 AM
 1.00000010916667	1:37:17 AM
 1.00000011816667	1:47:17 AM
 1.0000001182939	1:57:19 AM
 1.00000012045985	2:07:19 AM
 1.00000011746085	2:17:19 AM
 1.00000012995668	2:27:19 AM
 1.00000011879374	2:37:19 AM
 1.00000015428191	2:47:19 AM
 1.00000010679773	2:57:19 AM
 1.00000011446185	3:07:19 AM
 1.00000010679773	3:17:19 AM
 1.00000009780073	3:27:19 AM
 1.0000000925	3:37:19 AM
 1.000000101	3:47:19 AM
 1.00000009033333	3:57:19 AM
 1.00000008433333	4:07:19 AM
 1.000000092	4:17:19 AM
 1.00000007016667	4:27:19 AM
 1.00000011816667	4:37:19 AM
 1.00000009033333	4:47:19 AM
 1.000000107	4:57:19 AM
 1.00000012716667	5:07:19 AM
 1.0000001515	5:17:19 AM
 1.000000152	5:27:19 AM
 1.00000016266667	5:37:19 AM
 1.0000001515	5:47:19 AM
 1.000000158	5:57:19 AM
 1.000000164	6:07:19 AM
 1.0000001485	6:17:19 AM
 1.00000016566667	6:27:19 AM
 1.00000016866667	6:37:19 AM
 1.00000017166667	6:47:19 AM
 1.000000155	6:57:19 AM
 1.0000001665	7:07:19 AM
 1.00000016866667	7:17:19 AM
 1.0000001995	7:27:19 AM
 1.000000202	7:37:19 AM
 1.0000002025	7:47:19 AM
 1.0000002115	7:57:19 AM
 1.00000022216667	8:07:19 AM
 1.00000022516667	8:17:19 AM
 1.00000021916667	8:27:19 AM
 1.00000023116667	8:37:19 AM
 1.0000002055	8:47:19 AM
 1.00000022516667	8:57:19 AM
 1.0000002085	9:07:19 AM
 1.00000022283333	9:17:19 AM
 1.00000019966667	9:27:19 AM
 1.00000018	9:37:19 AM
 1.00000018133333	9:47:19 AM
 1.00000014966667	9:57:19 AM
 1.00000015816667	10:07:19 AM
 1.00000015266667	10:17:19 AM
 1.00000016033333	10:27:19 AM
 1.0000001415	10:37:19 AM
 1.0000001385	10:47:19 AM
 1.00000013233333	10:57:19 AM
 1.000000155	11:07:19 AM
 1.00000018066667	11:17:19 AM
 1.00000015966667	11:27:19 AM
 1.00000018366667	11:37:19 AM
 1.000000149	11:47:19 AM
 1.00000010866667	11:57:19 AM
 1.000000104	12:07:19 PM
 1.000000048	12:17:19 PM
 1.00000004515162	12:27:21 PM
 1.00000002199267	12:37:21 PM
 .999999988670443	12:47:21 PM
 .999999966677774	12:57:21 PM
 .999999932355881	1:07:21 PM
 .999999866877707	1:17:21 PM
 .999999878873709	1:27:21 PM
 .999999902032656	1:37:21 PM
 .999999871209597	1:47:21 PM
 .999999966177941	1:57:21 PM
 .9999998765	2:07:21 PM
 .999999868833333	2:17:21 PM
 .9999998255	2:27:21 PM
 .999999754666667	2:37:21 PM
 .999999719166667	2:47:21 PM
 .9999997025	2:57:21 PM
 .999999564145285	3:07:23 PM
 .999999479840053	3:17:23 PM
 .999999451182939	3:27:23 PM
 .999999346717761	3:37:23 PM
 .999999301566145	3:47:23 PM
 .999999304565145	3:57:23 PM
 .999999296901033	4:07:23 PM
 .999999260079973	4:17:23 PM
 .99999923742086	4:27:23 PM
 .999999219853431	4:37:25 PM
 .9999992964012	4:47:25 PM
 .999999276074642	4:57:25 PM
 .999999286737754	5:07:25 PM
 .999999312895701	5:17:25 PM
 .999999337887371	5:27:25 PM
 .999999327224259	5:37:25 PM
 .99999940853049	5:47:25 PM
 .999999425191603	5:57:25 PM
 .999999509496834	6:07:25 PM
 .999999537833333	6:17:25 PM


From: "Walt Williams" 
Subject: Test
Date: Sun, 13 Sep 1998 16:27:58 +0000

Please disregard....test.


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: "Francesco" 
Subject: SOUTHERN ITALY
Date: Mon, 14 Sep 1998 08:52:01 +0200

05.25
ML 4.6
DEPTH: 200 KM
LOC:  SOUTHERN TYRRENIAN SEA  - USTICA ISLAND
FELT VERY WELL IN NORTHERN SICILY AND PALERMO

I.E.S.N.  PSN ITALY
FRANCESCO NUCERA









05.25


ML 4.6


DEPTH: 200 =
KM


LOC:  SOUTHERN TYRRENIAN =
SEA  - USTICA=20
ISLAND


FELT VERY WELL IN NORTHERN SICILY =
AND=20
PALERMO


 


I.E.S.N.  PSN =
ITALY


FRANCESCO =
NUCERA


From: "Giacomo Sperandini" 
Subject: R: SOUTHERN ITALY
Date: Mon, 14 Sep 1998 18:44:24 +0200

Ok thanks Francesco and psn staff.
Congratulanions for mailist.
Bye bye next time events.
Hello dy Giacomo from Fano in italy.
    -----Messaggio originale-----
    Da: Francesco 
    A: PSN 
    Data: luned=EC 14 settembre 1998 9.21
    Oggetto: SOUTHERN ITALY
   =20
   =20
    05.25
    ML 4.6
    DEPTH: 200 KM
    LOC:  SOUTHERN TYRRENIAN SEA  - USTICA ISLAND
    FELT VERY WELL IN NORTHERN SICILY AND PALERMO
    =20
    I.E.S.N.  PSN ITALY
    FRANCESCO NUCERA









Ok thanks Francesco and psn =
staff.


Congratulanions for =
mailist.


Bye bye next =
time=20
events.


Hello dy Giacomo from Fano in italy.


    
-----Messaggio =
originale-----
Da:=20
    Francesco <franuc@......>
A: PSN =
<psn-l@.............>
Dat=
a:=20
    lunedì 14 settembre 1998 9.21
Oggetto: SOUTHERN =

    ITALY


    
05.25

    
ML 4.6

    
DEPTH: 200 =

    KM

    
LOC:  SOUTHERN TYRRENIAN =
SEA  -=20
    USTICA ISLAND

    
FELT VERY WELL IN NORTHERN =
SICILY AND=20
    PALERMO

    
 

    
I.E.S.N.  PSN =
ITALY

    
FRANCESCO=20
NUCERA


From: Art Kapoor 
Subject: Tradeoffs in the use of low noise op amps
Date: Mon, 14 Sep 1998 13:56:20 -0700

Dear All,

For those of you who do not have time to become electronic experts I
thought you might like to get a quick synopsis on low noise op amps.  

First of all there is two types of noise in op amps, current and voltage
noise. Voltage noise is the dominant source from low impedance sources
such as a pickup coil often used in amateur seismos.  However, current
noise does become a factor in overall amplifier performance.

Low voltage noise in op amps is obtained in two ways, large input
transistor size and large input stage current.  This is why low noise op
amps have high supply currents.  In addition, the large input stage
current allows the op amp to slew (change its output voltage) quickly. 
However, since siesmo signals move slowly this doesn't really help us
much.  The drawback is that op amps with high input stage currents have
high current noise. This current noise developed across the source
impedance will appear as voltage noise and be amplified accordingly. 
Therefore it always important to consider the entire amplifier system
including the source impedance to get lowest noise performamce.  A good
way to see this is to look at a data sheet for Analog Devices' (formerly
PMI) OP-470.  The data sheet shows a graph for peak to peak noise (0.1hz
to 10hz) vs source resistance for various op amps including the low
voltage noise OP-470 and the OP-400 (a quad OP-07).  Total noise
(remember by including a source resistance we are including the effect
of op amp current noise across the source, voltage noise from the source
itself (all resistances develop inherent voltage noise), and the op amp
voltage noise) when using the low voltage noise OP-470 is lowest for
source impedances below 17kohms.  Above that the OP-400 shows lower
total noise.  Most sensor coil impedances are between 1k and 10k. 
Remember, the penalty is in supply current, the OP-470 using 9ma for all
four op amps and the OP-400 only 2.4ma. For those of you dying to know
more the OP-470 data sheet goes into great detail on this subject.

Regards,
Art Kapoor

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Public Seismic Network Mailing List (PSN-L)


From: S-T Morrissey 
Subject: Re: Tradeoffs in the use of low noise op amps
Date: Mon, 14 Sep 1998 18:17:34 -0500 (CDT)

A very detailed treatment of amplifier selection vs. noise 
vs. coil resistance (including damping R) can be found in:

"Limits of Sensitivity of Inertial Seismometers with Velocity
Transducers and Electronic Amplifiers" by M.A.Riedesel, R.D.Moore,
and J.A.Orcutt; BSSA Vol 80, No 6, pp 1725-1752; December 1990.

It makes an important contribution in showing the importance
of the selection of the proper amplifier for a given coil 
(with damping) resistance. It shows in figure 3 (which has 
one axis mis-labeled as "frequency" when it should be labeled 
"coil resistance") such things as that using a OP-27 rather 
than a LT1012 (same as the dual LT1024) can reduce the noise 
when using an input of 400 ohms by a factor of 10. But they
are about equal with a 1000 ohm input, and the OP-27 is 10
times noisier with a 5000 ohm input.

The paper shows numerous instrumental measurements with various
combinations of sensors, including a 4.5 hz geophone. Their
bottom line is that for low frequency data (10 to 20 seconds)
from small velocity sensors, amplifiers need to be improved
by one to two orders of magnitude to resolve the earth noise 
minimum below 10 to 20 seconds. 

The paper only indirectly addresses the question of power consumption,
It doesn't mention the older micro-power options such as the 
LM4250 or the MC1776, but does evaluate the icl8021 and the newer 
LT-1079, both of which will operate from  the 30-50 microamp power 
supply currents needed for isolated battery operation while still 
having acceptable noise levels. In fact, when used with their
L4-C seismometer, the LT-1079 has only 10% of the noise of an
OP-27 at 1 hz. (Figure 7 of the paper).

(If you need a copy of the paper, send a stamped (x4) envelope to:
Sean-Thomas Morrissey ; Saint Louis University;
Department of Earth and Atmospheric Sciences;
3507 Laclede Ave.; St. Louis, MO 63103;)

Regards,
Sean-Thomas

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From: barry lotz 
Subject: New Event?
Date: Mon, 14 Sep 1998 17:27:22 -0700

Is anyone picking up a teleseismic event now? It appears to have started
at about 23:00 UTC. It's still coming in so I don't want to review the
file until it finishes.
                                           Barry

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Public Seismic Network Mailing List (PSN-L)


From: Canie Brooks 
Subject: Re: New Event?
Date: Mon, 14 Sep 1998 17:31:31 -0700

At 05:27 PM 9/14/98 -0700, barry lotz wrote:
>Is anyone picking up a teleseismic event now? It appears to have started
>at about 23:00 UTC. It's still coming in so I don't want to review the
>file until it finishes.
>                                           Barry

This was posted on RedPuma site:
14Sep1998 23:17:31.0 59.0N 166.0W 10 mb=5.8 A*LED SOUTHERN ALASKA
2342
14Sep1998 23:16:48.0 51.7N 173.0W 33 mb=5.6 A*NEI ANDREANOF ISLANDS,
ALEUTIA2338
14Sep1998 23:16:33.5 49.4N 170.6W 33 mb=5.4 A*NOR SOUTH OF ALEUTIAN ISLANDS
2344
14Sep1998 23:16:28.6 47.4N 177.0E 10 mb=6.0 A*SED SOUTH OF ALEUTIAN ISLANDS
2334

I'm not sure this is the event you are talking about...

See: http://seismo.ethz.ch/redpuma/redpuma_ami_list.html
>
>_____________________________________________________________________
>
>Public Seismic Network Mailing List (PSN-L)
>
>To leave this list email listserver@............. with the body of the 
>message: leave PSN-L
> 

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Public Seismic Network Mailing List (PSN-L)


From: barry lotz 
Subject: Re: New Event?
Date: Mon, 14 Sep 1998 18:27:21 -0700

Canie
    I think it is. I am confused about the Red Puma postings. Could
someone explain how the multiple lines of event listings are to be
interpreted? Are the the approximate epicenters calc'd from various
stations? or what.  Thanks
                                       Barry

Canie Brooks wrote:
> 
> At 05:27 PM 9/14/98 -0700, barry lotz wrote:
> >Is anyone picking up a teleseismic event now? It appears to have started
> >at about 23:00 UTC. It's still coming in so I don't want to review the
> >file until it finishes.
> >                                           Barry
> 
> This was posted on RedPuma site:
> 14Sep1998 23:17:31.0 59.0N 166.0W 10 mb=5.8 A*LED SOUTHERN ALASKA
> 2342
> 14Sep1998 23:16:48.0 51.7N 173.0W 33 mb=5.6 A*NEI ANDREANOF ISLANDS,
> ALEUTIA2338
> 14Sep1998 23:16:33.5 49.4N 170.6W 33 mb=5.4 A*NOR SOUTH OF ALEUTIAN ISLANDS
> 2344
> 14Sep1998 23:16:28.6 47.4N 177.0E 10 mb=6.0 A*SED SOUTH OF ALEUTIAN ISLANDS
> 2334
> 
> I'm not sure this is the event you are talking about...
>

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From: Canie Brooks 
Subject: Re: New Event?
Date: Mon, 14 Sep 1998 18:35:03 -0700

At 06:27 PM 9/14/98 -0700, barry lotz wrote:
>Canie
>    I think it is. I am confused about the Red Puma postings. Could
>someone explain how the multiple lines of event listings are to be
>interpreted? Are the the approximate epicenters calc'd from various
>stations? or what.  Thanks
>                                       Barry

Yep - its the reporting of multiple stations... if you go to their web page
and click on the heading AGY (?) it will give you a list of what stations
the letters stand for.

NEI = NEIC, NOR=norway, etc...

>
>Canie Brooks wrote:
>> 
>> At 05:27 PM 9/14/98 -0700, barry lotz wrote:
>> >Is anyone picking up a teleseismic event now? It appears to have started
>> >at about 23:00 UTC. It's still coming in so I don't want to review the
>> >file until it finishes.
>> >                                           Barry
>> 
>> This was posted on RedPuma site:
>> 14Sep1998 23:17:31.0 59.0N 166.0W 10 mb=5.8 A*LED SOUTHERN ALASKA
>> 2342
>> 14Sep1998 23:16:48.0 51.7N 173.0W 33 mb=5.6 A*NEI ANDREANOF ISLANDS,
>> ALEUTIA2338
>> 14Sep1998 23:16:33.5 49.4N 170.6W 33 mb=5.4 A*NOR SOUTH OF ALEUTIAN ISLANDS
>> 2344
>> 14Sep1998 23:16:28.6 47.4N 177.0E 10 mb=6.0 A*SED SOUTH OF ALEUTIAN ISLANDS
>> 2334
>> 
>> I'm not sure this is the event you are talking about...
>>
>
>_____________________________________________________________________
>
>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: Aleutian Event
Date: Mon, 14 Sep 1998 23:46:12 -0500 (CDT)

Re confusion of multiple listings of the event:

NEIS lists it (via FTP to Finger Quake)

origin 23:16:47 , 51.83N, 173.09W, d 33km Ms. 5.9 Andreanof Isl, Aleutians.
(this is about the right latitude and longitude for an event in the 
trench there; some of those other locations are way off)
The closest station was (of course) at ADAK, with an arrival at 23:17:27.

........it was nicely recorded at St. Louis......
........even on the 4.5hz geophone fedback to operate at 21 seconds .

Regards,
Sean-Thomas

_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: meredith lamb 
Subject: Re: Aleutian Event
Date: Mon, 14 Sep 1998 23:02:55 -0600



S-T Morrissey wrote:

> .......it was nicely recorded at St. Louis......
> .......even on the 4.5hz geophone fedback to operate at 21 seconds .
>
> Regards,
> Sean-Thomas
>

Sean,

Any more details on the geophone deal, i.e., cut open geophone,
is circuit the same as used on the STM-8?  Etc.  Any web site
possiblity of a shown quake trace using the geophone result?
Curio item for sure.

Any other exotic seismic trials using other items not previously
mentioned?  Piezo?  LVDT?  Tried any conversions on any of
your number of other older seismos?

Thanks, Meredith Lamb




_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: John Hernlund 
Subject: Re: Aleutian Event
Date: Tue, 15 Sep 1998 07:58:00 -0700 (MST)

On Mon, 14 Sep 1998, S-T Morrissey wrote:
> origin 23:16:47 , 51.83N, 173.09W, d 33km Ms. 5.9 Andreanof Isl, Aleutians.
> (this is about the right latitude and longitude for an event in the 
> trench there; some of those other locations are way off)
> The closest station was (of course) at ADAK, with an arrival at 23:17:27.
> 
> .......it was nicely recorded at St. Louis......
> .......even on the 4.5hz geophone fedback to operate at 21 seconds .

   Yes, we even had a nice recording in Tempe, AZ.  I thought for sure it was
a larger event, the surface waves looked like they belonged to a Ms>6.5 

******************************************************************************

			       John Hernlund
     		          E-mail: hernlund@.......
      WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/
		    http://www.public.asu.edu/~hernlund/

"It is easier to excuse an ignorant person who claims that theory is
unnecessary and dispensable in his supposed practice, than to excuse a
Sophist who concedes its value to the schools (as, perhaps, only a mental
exercise) but who at the same time maintains that matters are quite
different in practice- that as one leaves school to enter the world, one
will realize one has been pursuing empty ideals and philosophical dreams-
and, in a word, that what sounds good in theory is of no practical
use."
-Immanuel Kant, On the Proverb: That May be True in Theory, But Is of No
Practical Use

******************************************************************************


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Public Seismic Network Mailing List (PSN-L)


From: "Walt Williams" 
Subject: Aleutian Event & GeoPhone Question
Date: Tue, 15 Sep 1998 11:29:40 +0000

Hello Sean-Thomas,

>>Walt 
I know you are busy. When it is convenient could you
spare a few words on:

>>Sean-Thomas
........even on the 4.5hz geophone fedback to operate at 21 seconds. 

>>Walt
How does one lengthen the period of a fixed period sensor?

Thank you.

Walt Williams, 98.09.15
dfheli@..............

================================================


------- Forwarded Message Follows -------
Date:          Mon, 14 Sep 1998 23:46:12 -0500 (CDT)
From:          S-T Morrissey 
To:            psn-l@.............
Subject:       Aleutian Event
Reply-to:      PSN-L Mailing List 

Re confusion of multiple listings of the event:

NEIS lists it (via FTP to Finger Quake)

origin 23:16:47 , 51.83N, 173.09W, d 33km Ms. 5.9 Andreanof Isl,
Aleutians. (this is about the right latitude and longitude for an
event in the trench there; some of those other locations are way off)
The closest station was (of course) at ADAK, with an arrival at
23:17:27.

........it was nicely recorded at St. Louis......
........even on the 4.5hz geophone fedback to operate at 21 seconds .

Regards,
Sean-Thomas

_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


_____________________________________________________________________

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From: "Ron Horton" 
Subject: Thanks
Date: Tue, 15 Sep 1998 16:59:55 -0000

Hi to All,

A big thank you to John Cole & Frank Cooper. John & I tested my =
completed Lehman on his chart recorder. We got a good clean signal at =
the lowest gain setting Larry's amp board provides. I should have =
digital set up completed in a few days & hope to start sending event =
files to PSN soon.

Have a great day !

Ron Horton










Hi to All,


 


A big thank you to John Cole & =
Frank Cooper.=20
John & I tested my completed Lehman on his chart recorder. We got a =
good=20
clean signal at the lowest gain setting Larry's amp board provides. I =
should=20
have digital set up completed in a few days & hope to start sending =
event=20
files to PSN soon.


 


Have a great day !


 


Ron Horton


 


From: meredith lamb 
Subject: Re: Thanks
Date: Tue, 15 Sep 1998 17:41:26 -0600

Ron Horton,

Congratulations on your new setup!  I'am beginning to think that
Texas is making a run for the lead in number of members-ha.

Hmmm, .......is this near the time of year for the annual sloppy
Colorado - Texas "border", over ripe tomato throwing war?  I
think the Texas tomatoes are called "the stars of Texas are
upon you" or something like that.  This year however, the Texas
crops underwent a drought; whereas the Colorado crop got ALOT
and ALOT of water.  Seems, sort of, fair too me.  Cultural exchange
events like this are very important....

Meredith Lamb


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: johnccole@........ (john c cole)
Subject: Re: Thanks
Date: Tue, 15 Sep 1998 20:14:59 -0500

meredith
  ron and i are both  thankful to have a good friend like frank cooper 
to show us the way. frank has been more than generous with his time and
materials. we also appreciate this net and the members  who supply us
with technical information. gentlemen, do you know how important that is
to the novice? 
  the reason for the bountiful harvest  is the hard working gardener..

                                                     your friend john c
cole w5auh

_____________________________________________________________________
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Get completely free e-mail from Juno at http://www.juno.com
Or call Juno at (800) 654-JUNO [654-5866]

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From: meredith lamb 
Subject: Re: Thanks
Date: Tue, 15 Sep 1998 22:23:37 -0600



john c cole wrote:

> meredith
>   ron and i are both  thankful to have a good friend like frank cooper
> to show us the way. frank has been more than generous with his time and
> materials. we also appreciate this net and the members  who supply us
> with technical information. gentlemen, do you know how important that is
> to the novice?
>   the reason for the bountiful harvest  is the hard working gardener..
>
>                                                      your friend john c
> cole w5auh
>

John Cole,

Yes, we all need the human interaction aspect.  It can get very
empty and meaningless without it.  Sharing the joys and sorrows
of ourselves and of others similar needs is really more living than
burrowing a hole with other illusions of nonsense.  The best
people on earth are the ones who can and do give to others in
whatever type of assistance they possibly can do.

Am still curious about you and Ron Horton's setups down there
and particularly in regard to the seismo's detailed makeups.
Any more detailed written descriptions coming up sometime via
PSN email?

Uh.....decided to not "give" any large juicy tomatoes to the
great Colorado-Texas tomato war cause...they look too good
and I hear the Texas bunch is all planning to use butterfly nets
to catch and take them home as edible war souvenir's.  You
guys don't play fair either....ha.

Have fun, Meredith Lamb
















_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)


From: S-T Morrissey 
Subject: period lengthening
Date: Wed, 16 Sep 1998 00:58:13 -0500 (CDT)

Regarding extending the period:

The operating period of almost any well behaved pendulum
can be extended by a factor of from 30 to 100 by incorporating
a proper feedback system with a suitable displacement
transducer as input with output to a suitable feedback
force coil and magnet.  The details of such a system are
described in detail in the paper on the STM broadband
seismometer at:
http://www.eas.slu.edu/People/STMorrissey/index.html

For example, a 1 second pendulum can be made to operate
as a 30-second sensor. A 15 second long period sensor is
operating at 600 seconds. The commercial STS-1, the best
low noise broadband (and priciest) has a 6 second pendulum
but operates at 360 seconds.

The serious limitation is the design factor that the M*T*Q product 
should be greater than 1 for acceptable self noise levels,
where: M= mass in kg, T = period in seconds, and Q is the inverse 
of the mechanical damping: Bo. (for a closed seis like a L4-C, 
Bo = 0.25, so Q = 4; for a quartz fiber torsion suspension, where 
the mass will oscillate almost indefinitely, Bo might be 0.01, 
so Q would be 100, allowing a much smaller mass..  
Recently in an experiment was done to configure a 4.5 hz geophone 
to work at 21 seconds; but with a 29 gram mass, MTQ is really poor, 
like 0.032!, so it is 100x noisier than the STM-8.

Regards,
Sean-Thomas

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From: lahr@..................
Subject: Re: Gem and Mineral Show
Date: Wed, 16 Sep 1998 09:50:54 -0600 (MDT)


If you'll be near Denver this weekend, don't miss the Denver
Gem and Mineral Show.  It's open Friday from 9 AM to 6 PM,
Saturday from 10 AM to 6 PM, and Sunday from 10 AM to 5 PM.

I'll be there in the Kid's Corner with a hands-on display of 
"Table Top Seismology."  This includes a sliding-rock make-a-
quake demo, some simple devices to illustrate how a seismometer
works, a shake table with a design challenge, and more!

In fact if anyone (Meredith? Edward?) wants to help me out at the
booth for a few hours, I'll see that they get a free ticket!

The show is at the Expo Hall of the Merchandise Mart, I25 &
58th Avenue, Denver.

Cheers,
JCLahr
################################## John C. Lahr
################################# Seismologist
################################ U.S. Geological Survey
############################### Geologic Hazards Team, MS966
############################## PO Box 25046
#############################/##############################
############################/###############################
Denver, Colorado 80225-0046 ################################
    Phone: (303) 273-8596 ##################################
     Fax: (303) 273-8600 ###################################
         lahr@........ #####################################
                http://giseis.alaska.edu/lahr
               http://lahr.org/john-jan


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From: meredith lamb 
Subject: Re: Gem and Mineral Show
Date: Wed, 16 Sep 1998 16:48:29 -0600

John Lahr,

Your offer sounds like fun and normally I think I'd jump to do
some assistance.  However, presently my wife's medical
problems, preclude any participation at this time.   Maybe next
year, as the saying goes......

I do have on hand a box of smoky quartz crystals, which perhaps
the kids visiting your booth, might be interested in receiving.
They are mostly not gem quality stuff, but they do exhibit the
crystalline mineral habit.  Or, perhaps they could "dress up"
your display, or both.  Guessing its about 20 pounds worth,
and mostly smaller thumb size crystals.  I have no use for such,
and can briefly deliver to your place.  Free of course....let me
know.

Ah.....the Denver Gem and Mineral show.  Haven't been to one
of those in many years.  Last one was maybe the late 70's or so.
Fairly big affair as I remember.  Alot of vendors with lucious
specimens and afew large faceted show only gemstones.
Flowers of the mineral kingdom.....crystals.

(You really wanted to read this stuff-ha)

Reminds me of the 60's & 70's rock hounding days.  Platte
Mountain south west of Denver (also called Devils Head) in
the mountain range.  At the time the main rock hounding area
was a wide open affair, picnic areas and various short roads
branching off into areas.  Main draw was smoky quartz crystals
and pink feldspar in pockets occuring sporadically around the
area.  They don't allow any more digging since maybe 1985.
Alot of big quartz crystals came out of the area in the first half
of this century, with big maybe being 25 pounders.  Original
main draw was a pegmatite south of the mountain which yielded
topaz and a broad host of rarer mineral specimens early in the
century.  Like all noted locations, that site has been throughly
picked over countless times.  Being a public area, there was alot
of "claim jumping" so to speak.  If someone found a good spot,
unless they cleaned it out, someone else would-ha.  It wouldn't
be unusual for the individuals to camp out at their sites and
spend days there.  Most of the crystals there did not come close
to being of the quality of the Brazilian minerals in beauty or even
toughness.  Nevertheless, there were alot of smaller pockets
scattered around the mountain.  Part of the routine of rock
hounding is that if you do find a potentially good spot, that after
you were through for the day, you would re-cover the dig site in
hopes of coming back at another time and exploring further, or
cover it knowing you weren't coming back.

The area is red granite, and is some 17 million year old material
for the site.  As I recall it is volcanic in nature, with the 3 adjacent
eroded pipes giving the area its assumed name of Devils Head.
Like quartz gold prospecting, amateurs usually follow quartz
float uphill to the source, if it still exists.  I usually just used a
shovel and crowbar, as none of my excursions were really never
meant to be other than a pleasant past time in the mountains.
Most of the pockets were either formed out of old gas/water
bubbles or rock fractures seam affairs.

As I said earlier in so many words the competion was kind of
fierce.  Even had several occurrances of people using
binoculars surveying and even watching other people-ha.

The most interesting "event" was finding clear quartz float
on the side of a hill, somewhat away from the roads.  Followup
digging indicated a winding path up the hill to an abandoned
older "dig" (not fresh ground digging/dump indications).   A
brief forray into the same area, kept on giving small milky
quartz crystals.  Being I was a weekend "warrior", I had to
give it up with nightfall coming on.

The next weekend I came back.   Low and behold, the same
spot had been dig up and recovered again by another person!
Do I give up and go looking elsewhere or not was the question.
Decided to see what or how far they had progressed.  Reaching
the bottom, showed that there were still indications of small
crystals trending northward from the original dig site.  After
doing more excavation, the number of small crystals still
persisted.  I came back the next day and continued, but the
signs were still there.  I covered the hole late Sunday and left.

Yes....you got it....someone came back during the weekday
and had further progressed trending north ward.  I got the
same good signs for an additional week thereafter, and yes,
the hole had been dug further by someone else again during
the weekday sometime.

The next weekend was different this time.  The excavation
had not been totally covered up this time.  Acouple hours into
new rock and smaller crystals, I came upon a quartz dome shaped
outline about 2 & 1/2 feet in diameter.  Tapping on it with the
crowbar gave a muffled hollow sound.  This was like a fused
quartz cap and proved to be about 6 inches thick.  Good thing
it wasn't noon yet-ha.  It took about 45 minutes of crowbar
smashing and prying to break the cap.  Lifting the entry pieces
showed a layer of  water and thick red clay like mud.  Inserting
my hand into the mud and feeling around, I could sense the
sharp points of some 8 crystals and the longest was about
7-8 inches long by maybe 2" in diameter at the most.  The
bottom of the cavity was about the length of the arm up to the
elbow.  OH, OH, a rockhounds buried treasure was here!
I used a discarded tin can to sipeon off the water and mud.
Removing the crystals and matrix proved to be impossible.
Ended up prying the crystal bottoms and removing that way.
It was getting dark by the time I was satisfied with the
retrieval of all the crystals.  I covered it up to about the
same height as left by the previous companion claim
jumper-ha.   I think I'am glad I wasn't around to hear the
claimjumpers after they saw the crystal bases in the granite
in the following weekdays-ha.  The crystals themselves were
not exactly the greatest in quality, but they sure were pretty
too me!

End of story???....not quite.  The next weekend I came out
again (can't get too much of a good thing), and again the
hole had been uncovered.  This time they went straight down
into bare granite with some gusto.  Further examination
showed a "pipe" going west and uphill.  Followed that up to
the surface and found quite afew additional milky crystals,
before it petered out.   Afew weeks later I came back, and
of course the claim jumpers had expanded the same route-ha.

Anyway, ...I think more than anything, this story is about the
same as building a seismograph.  Alot of problems, diversions
and resolutions along the way....but when it works, its a
treasure you don't ever forget, and the whole episode is
really worthwhile.

Meredith Lamb





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From: lahr@..................
Subject: Lehmann sensor
Date: Thu, 17 Sep 1998 11:27:46 -0600 (MDT)

On this page:

http://psn.quake.net/info/homefaq.txt

it is stated that:

Aside:
        No one seems to know if the Lehman(n) sensor is named after the author,
        James D. Lehman, or the famed Danish seismologist, Inge Lehmann, who
        published a paper in 1936, that postulated that the earth held an inner
        core estimated to be about the size of our moon within the outer core.
        If someone has some information on this please forward it to me
        so I can include it in the next update of the FAQ. (kjn@...........

I met James Lehman at at National Science Teachers Association meeting in
Seattle in 1996.  He is indeed the person that the Lehman is named after, although
he was a bit shy about this. His talk was "Seismology in the Classroom:  Sensor
Design and How to do it."

He was not on Email at that time, nor into digital recording, but it might be 
interesting to contact him now to see if he would be interested in the PSN.

His address is:

Jim Lehman
Physics Department
Harrisonburg, Virginia 22807
Phone: (540) 568-6643

JCLahr
################################## John C. Lahr
################################# Seismologist
################################ U.S. Geological Survey
############################### Geologic Hazards Team, MS966
############################## PO Box 25046
#############################/##############################
############################/###############################
Denver, Colorado 80225-0046 ################################
    Phone: (303) 273-8596 ##################################
     Fax: (303) 273-8600 ###################################
         lahr@........ #####################################
                http://giseis.alaska.edu/lahr
               http://lahr.org/john-jan



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From: Ted Blank 
Subject: Re: Lehmann sensor
Date: Thu, 17 Sep 1998 11:55:07 -0700 (PDT)


Clearly the case.  See Scientific American, July 1979, Amateur Scientist 
column.  All about Jim Lehman and his contraption.  His name was used by 
members of the PSN as the natural identification of the design or 
discovery.  Long history of this - see Compton Effect, etc.

One thing we haven't done is named a unit of measurement after him.  
Maybe the Lehman Scale could be defined in terms of how high you have to 
jump in the garage to get a standard deflection on a Lehman sensor.


Ted Blank
San Jose, California

On Thu, 17 Sep 1998 lahr@.................. wrote:

> On this page:
> 
> http://psn.quake.net/info/homefaq.txt
> 
> it is stated that:
> 
> Aside:
>         No one seems to know if the Lehman(n) sensor is named after the author,
>         James D. Lehman, or the famed Danish seismologist, Inge Lehmann, who
>         published a paper in 1936, that postulated that the earth held an inner
>         core estimated to be about the size of our moon within the outer core.
>         If someone has some information on this please forward it to me
>         so I can include it in the next update of the FAQ. (kjn@...........
> 
> I met James Lehman at at National Science Teachers Association meeting in
> Seattle in 1996.  He is indeed the person that the Lehman is named after, although
> he was a bit shy about this. His talk was "Seismology in the Classroom:  Sensor
> Design and How to do it."
> 
> He was not on Email at that time, nor into digital recording, but it might be 
> interesting to contact him now to see if he would be interested in the PSN.
> 
> His address is:
> 
> Jim Lehman
> Physics Department
> Harrisonburg, Virginia 22807
> Phone: (540) 568-6643
> 
> JCLahr
> ################################## John C. Lahr
> ################################# Seismologist
> ################################ U.S. Geological Survey
> ############################### Geologic Hazards Team, MS966
> ############################## PO Box 25046
> #############################/##############################
> ############################/###############################
> Denver, Colorado 80225-0046 ################################
>     Phone: (303) 273-8596 ##################################
>      Fax: (303) 273-8600 ###################################
>          lahr@........ #####################################
>                 http://giseis.alaska.edu/lahr
>                http://lahr.org/john-jan
> 
> 
> 
> _____________________________________________________________________
> 
> Public Seismic Network Mailing List (PSN-L)
> 
> To leave this list email listserver@............. with the body of the 
> message: leave PSN-L
> 

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From: barry lotz 
Subject: Eddy current sensor
Date: Thu, 17 Sep 1998 20:43:45 -0700

Sean Thomas et al
   The latest issue of Sensors magazine has an interesting article on
eddy current position sensors. The author claims nanometer resolution.
The geometry and electronics looks simple. Have any seismic sensors used
this method if measuring deflection? If so how was the performance?
                                             Regards
                                                 Barry

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From: meredith lamb 
Subject: Re: Eddy current sensor
Date: Thu, 17 Sep 1998 23:28:54 -0600



barry lotz wrote:

> Sean Thomas et al
>    The latest issue of Sensors magazine has an interesting article on
> eddy current position sensors. The author claims nanometer resolution.
> The geometry and electronics looks simple. Have any seismic sensors used
> this method if measuring deflection? If so how was the performance?
>
> Regards                                                 Barry
>
>

Barry,

Is it possible to describe more on the article, i.e., did they use a coil,
or something else?  Is it somewhat like a variable reluctance sensor?
Or, an electronic circuitry from the eddy current source? Etc.???

Went to the http://www.sensorsmag.com, but they don't list September
articles; which I presume it is in.   The magazine seems to be mainly
for presently active companys buyers/personnel, and even with a
subscription (somehow), its not cheap, and maybe delayed 6 weeks.
I doubt it is a general library type magazine.  The previous articles
are super condensed, and incomplete on the web site.

Interested....but shut out, so too speak....is why I ask.

Meredith Lamb




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From: Nick & Sophie Caporossi 
Subject: Measuring deflection
Date: Fri, 18 Sep 1998 09:19:46 -0400

Hi all:

 Need more help. Now that I have gotten the hinge and pivot problem pretty
well resolved "thanks to the many responses", I am now having some trouble
determining what is the distance that the Boom will move when sensing an
event. I also find that the coil and magnet combination is having a far
more damping effect than I expected it to have. In reading over some of the
details which other members have written about on the subject, I'm not sure
if I should try a larger magnet and smaller coil or vice versa. Any help
would be greatly appreciated.
(I wound the coil on a 10 penny nail, 2 inches in length, about 800 turns)

 As a point of interest, for holding the boom to the vertical post. I found
that a Fishing line "20 pound or better test" is working quite well. The
non Stretch Spider brand fishing line is what I used.

Nick Caporossi

    

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From: "James M Hannon" 
Subject: Re: Eddy current sensor
Date: Fri, 18 Sep 1998 10:48:57 -0500



Meridith,
I had a look at the Sensors mag. article.  The sensor is essentially the
same as the VRDT except that the one described in the article is single
ended rather than a bridge circuit. It's claim to fame is that it will work
with any metal rather than just iron.  For seismograph applications I would
stay with the VRDT.

Jim Hannon




meredith lamb  on 09/18/98 12:28:54 AM

Please respond to PSN-L Mailing List 

To:   PSN-L Mailing List 
cc:
Subject:  Re: Eddy current sensor







Barry,

Is it possible to describe more on the article, i.e., did they use a coil,
or something else?  Is it somewhat like a variable reluctance sensor?
Or, an electronic circuitry from the eddy current source? Etc.???

Went to the http://www.sensorsmag.com, but they don't list September
articles; which I presume it is in.   The magazine seems to be mainly
for presently active companys buyers/personnel, and even with a
subscription (somehow), its not cheap, and maybe delayed 6 weeks.
I doubt it is a general library type magazine.  The previous articles
are super condensed, and incomplete on the web site.

Interested....but shut out, so too speak....is why I ask.

Meredith Lamb












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From: "Al Allworth" 
Subject: RE: Measuring deflection
Date: Fri, 18 Sep 1998 08:53:23 -0700



> -----Original Message-----
> From: Nick & Sophie Caporossi [mailto:nickcap@..............
> Sent: Friday, September 18, 1998 6:20 AM
> To: psn-l@.............
> Subject: Measuring deflection
>
>
> Hi all:
>
>  Need more help. Now that I have gotten the hinge and pivot problem pretty
> well resolved "thanks to the many responses", I am now having some trouble
> determining what is the distance that the Boom will move when sensing an
> event. I also find that the coil and magnet combination is having a far
> more damping effect than I expected it to have. In reading over
> some of the
> details which other members have written about on the subject,
> I'm not sure
> if I should try a larger magnet and smaller coil or vice versa. Any help
> would be greatly appreciated.
> (I wound the coil on a 10 penny nail, 2 inches in length, about 800 turns)


Hi Nick and the group,

If you have left the nail in the coil the period of the boom will be greatly
shortened by the attraction of the magnet to the nail. It works better for
the coil to be wound on a non-metalic tubular form large enough for the
magnet to enter without touching. For best sensitivity the arrangement
should produce the greatest flux change through the turns of the coil for a
given amount of motion.

					Al Allworth


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From: Karl Cunningham 
Subject: Re: Measuring deflection
Date: Fri, 18 Sep 1998 10:27:47 -0700

Nick --

The Lehman (or "garden gate") design is simulating a very long pendulum,
which has a natural period -- the time it takes the mass to swing over and
return to its original position.  For earth movements with periods shorter
than the natural period, the mass should (more or less) stay put while the
earth moves under it.  This is what your coil/magnet will be able to pick
up.  For earth movements with periods longer than the natural period, the
mass will (more or less) move with the earth and your coil/magnet will see
little relative motion.

The response is second order, which means the actual amount of movement of
the mass relative to the BASE will decrease as the square of the signal
period for periods LONGER than the natural period.  It also means that the
movement of the mass relative to an INERTIAL FRAME will decrease as the
square of the signal period for periods SHORTER than the natural period.
i.e., the mass will stay put and let the earth and the base move under it.
This response is similar to a capacitor and inductor connecte together, in
the electronics world.

This still doesn't address what happens with signals near the natural
period, which gets to your second question.  If you have very little
friction in the mechanics, and very little damping from the coil, the mass
will swing much more than the movement of the earth with signals with
periods near the natural period.  In other words, it will resonate.  To do
any kind of quantitative work, having these resonances is undesireable, and
this is where damping comes in.

One way to measure the amount of damping is to pull the mass to one side
and let it go.  See how many times it swings back and forth before the
energy is dissipated (it stops moving).  Others can probably shed more
light on this, but if the mass is swinging much less far (half to a third
of the original distance) at the beginning of the second cycle, the damping
is probably ok.

As to what may cause excessive damping, one thing comes to mind:  The
magnet passing by the iron nail will cause eddy currents in the nail, which
in turn cause heating of the nail, which takes energy from the boom and
dampens the swing.  Winding the coil on a non-conductive form may help.  In
most cases, it is necessary to introduce some artificial damping (resistor
across the output of the coil) to properly damp the swing.

Karl Cunningham
La Mesa, CA.
PSN station #40
karlc@.......


At 09:19 AM 9/18/98 -0400, you wrote:
>Hi all:
>
> Need more help. Now that I have gotten the hinge and pivot problem pretty
>well resolved "thanks to the many responses", I am now having some trouble
>determining what is the distance that the Boom will move when sensing an
>event. I also find that the coil and magnet combination is having a far
>more damping effect than I expected it to have. In reading over some of the
>details which other members have written about on the subject, I'm not sure
>if I should try a larger magnet and smaller coil or vice versa. Any help
>would be greatly appreciated.
>(I wound the coil on a 10 penny nail, 2 inches in length, about 800 turns)


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From: S-T Morrissey 
Subject: Re: Eddy current sensor
Date: Fri, 18 Sep 1998 18:39:58 -0500 (CDT)

Barry,
 
You are probably awre of the abundance of proximity sensors available 
that operate by induced eddy currents in non-ferrous objects. Most are 
designed as yes/no swithches to count things. Some are used as actual 
distance measuring devices where the absorption of the excitation energy in
the conductive target produces an output. They are generally neither
sensitive nor linear. I have not seen the articly you refer to.

Regarding the consideration of non-ferrous material for the core of 
an LVDT or the vane in a VRDT:  highly permeable ferrous materials are 
used for maximum sensitivity. I have done some experimenting on the
VRDT with strips of brass, stainless (non magnetic) steel, and aluminum. 
They will provide an output, but at about 1% of a ferrous vane over 
the whole width of the gap. I suspect that the reactance change
is because the excitation coils induce eddy currents in these conductors,
which means it would be strongest near either pole face, but highly
non-linear in between. A wider gap with a thicker copper vane might
do better.

Since we need all the available output from the transducer, to avoid
the need for much more subsequent amplification, I would stick with
ferrous cores or vanes. I am  currently amplifying the output of the
VRDT (at about 50mv.micron) by 30X (to 1 500 000 volts/meter) to improve
the short period response of the broadband configuration. 
However, I have found that the vane and inductors can be weakly
magnetized by passing too close to the magnet, so I demagnetize them
with a tape head demagnitizer or by passing them near the loop of a 
large solder gun.

regards,
Sean-Thomas

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From: "Rex Klopfenstein, Jr." 
Subject: VBB Seism Questions
Date: Fri, 18 Sep 1998 19:55:11 -0400

This note is really addressed to S-T Morrissey, but maybe someone else
can answer.  Also, this will get the responses in the archives.

I decided to start building a VBB described at S-T Morrissey's site.  I
am working on generating a schematic of the entire electronic circuit in
AutoCAD so I can search my 'junk' rack for parts.  I have just entered
the sine wave oscillator as shown in documentation.  I have several
questions and could not find any answers in the archive.

My first question has to do with the oscillator (CD4047).  In checking
the data sheet, it seem like the input voltage and ground do not agree
with 'true gating' astable multivibrator function (pins 4,5,6)shown in
mfg documentation.  What is the frequency of the oscillator?  According
to the data sheet, the formula is Freq = 4.4RC (output @ pin 10).  By
the way, which frequency is the best 5K or 40K?

What size do you recommend for the two capacitors located at the power
+/-9 power connections?  I take it that they are tant's.  By the way,
what is the purpose of the 100 ohm resistors in series with the power
feeds?

I am getting ready to draw the bridge amp/demod/filter/amp next.  I am
not really familar with VRDT circuit and have questions about the
insertion of the dual coil VRDT coil assembly into the circuit.  Is the
transformer shown after A4 of the oscillator output amp the VRDT?  How
does the VRDT coils attach to the bridge amplifier and resistors?

When I get the answers to the above questions and incorporate into my
drawing I will post a .dxf file of the oscillator section on my
website.  If possible I would like individuals who are familiar with
these circuits to download and check and let me know about any
problems.  As I add other sections, I will post for the review process.
When it is complete, I will gladly furnish a complete .dxf to S-T
Morrissey so he can control general distribution.  I will also generate
a complete components list (most likely an EXCEL spreadsheet).

Most importantly this drawing and components should be reviewed by S-T
Morrissey for accuracy.  If any copyright is required, please provide
and I will incorporate.

Thanks in advance

Rex Klopfenstein, Jr.
Bowling Green, OH


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From: barry lotz 
Subject: Re: Eddy current sensor
Date: Fri, 18 Sep 1998 20:13:36 -0700

Meridith
     As Sean Thomas mentioned it is non linear and sensitive to
temperature changes among other things. It's basic geometry is a coil
constructed in a plane . It is subjected to AC current in the order of 1
MHZ. It resonates with a capacitor in the circuit. The variation in
distance from an adjacent metal surface causes variations in the coils
impedance.The article says if one stays within ~1/2 of the coil diameter
from the metal surface the linearity is not to bad. Evidently there will
be other articles on error corrections. 
                                         Barry
 
PS  Jim- I thought the VRDT was more like the plate arrangement of the
SG. I didn't see where a coil/inductance was involved. Can you
elaborate.

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From: Karl Cunningham 
Subject: Radio-Controlled Clock
Date: Fri, 18 Sep 1998 20:53:55 -0700

Greetings, all --

I came across a product from Oregon Scientific, model RM 116E that is very
similar to the Radio Shack radio-controlled clock described by Larry
Cochrane on this list last January 13.  See
http://www.oregonscientific.com/prdcltim.html .  In fact, I think it is the
same as the RS clock but in a slightly different case and with a slightly
different LCD readout.  The antenna unit looks identical.

Oregon Scientific's web page lists the price at $100, but it was at Fry's
(California electronics superstore) for $30.  I am using the RS unit and it
works great at keeping SDR's time synchronized to WWVB.  (Many thanks to
Larry for helping me with this.)


Karl Cunningham
La Mesa, CA.
PSN Station #40
karlc@.......

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From: barry lotz 
Subject: Re: Radio-Controlled Clock
Date: Fri, 18 Sep 1998 21:24:06 -0700

Karl
    I was wishing to include the clock in my system but was having
trouble with the receiving signal. It is not always received or is
intermittent. The Radio Shack unit checks the time at early morning
hours for better success. Do you have a way of checking for errors in
the incoming data or time intervals?
                                                     Regards
                                                     Barry

Karl Cunningham wrote:
> 
> Greetings, all --
> 
> I came across a product from Oregon Scientific, model RM 116E that is very
> similar to the Radio Shack radio-controlled clock described by Larry
> Cochrane on this list last January 13.  See
> http://www.oregonscientific.com/prdcltim.html .  In fact, I think it is the
> same as the RS clock but in a slightly different case and with a slightly
> different LCD readout.  The antenna unit looks identical.
> 
> Oregon Scientific's web page lists the price at $100, but it was at Fry's
> (California electronics superstore) for $30.  I am using the RS unit and it
> works great at keeping SDR's time synchronized to WWVB.  (Many thanks to
> Larry for helping me with this.)

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From: Karl Cunningham 
Subject: Re: Radio-Controlled Clock
Date: Sat, 19 Sep 1998 00:16:15 -0700

Barry --

Larry suggested what sounds like a good way to check the timing accuracy:
Look at the waveform of WWV with a scope while triggering it from the WWVB
receiver.  I haven't tried that yet.  When I modified the clock, I put in
an LED to indicate the state of the data output line from the clock to SDR
(as Larry's schematic shows).  When the signal is good, the LED shows a
clean signal (either on or off, flashing once per second), and when the
signal is noisy the LED goes randomly on and off.  At my location, the
signal appears to be good about 80% of the time.

I put an optical isolator between the clock and my computer that runs SDR
to cut down on the noise from the computer to the clock's receiver, and
lengthened the cable to the antenna to about 25' using shielded cable.  I
found a location for the antenna away from the computer and flourescent
lights that seems to get a pretty good signal.  I played with antenna
location and orientation for quite a long time before I had what I think is
optimum.  Some locations are just plain lousy, while only a few feet away
is good.

When I was fiddling around, I found a web page that describes a loop
antenna and preamp for WWVB.  See http://www.lakeweb.com/dbLabs/wwvb/  I
figured it might help if I had trouble.

Also, I think SDR has code that looks at the pulses and throws out noisy
ones that don't fit the trend.

Hope this helps,

Karl Cunningham
La Mesa, CA.
PSN Station #40
karlc@.......


At 09:24 PM 9/18/98 -0700, you wrote:
>Karl
>    I was wishing to include the clock in my system but was having
>trouble with the receiving signal. It is not always received or is
>intermittent. The Radio Shack unit checks the time at early morning
>hours for better success. Do you have a way of checking for errors in
>the incoming data or time intervals?


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From: Karl Cunningham 
Subject: Re: Radio-Controlled Clock
Date: Sat, 19 Sep 1998 09:44:38 -0700

Barry --

Re: My message of last night.  I could have been clearer:

>Look at the waveform of WWV with a scope ...

should have read:

Look at the demodulated audio waveform from WWV with a scope...

Sorry for any confusion.

Karl Cunningham
La Mesa, CA.
PSN Station #40
karlc@.......


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From: "Ron Horton" 
Subject: Cultural Exchange
Date: Tue, 15 Sep 1998 23:23:51 -0000

Meridith,

Thanks for sharing your knowledge of cultural exchange programs ! I'm =
sure that with the influence Texas PSN members have in the state we =
could secure a personal invitation for you to participate (on the Texas =
side) if you like. Ha ! On the more serious side, thanks for all of your =
input to the list. As a fairly new member, I find the information =
exchage to be interesting and informative. Thanks for the encouragement =
as well.

Have a great day !

Ron










Meridith,


 


Thanks for sharing your knowledge of =
cultural=20
exchange programs ! I'm sure that with the influence Texas PSN members =
have in=20
the state we could secure a personal invitation for you to participate =
(on the=20
Texas side) if you like. Ha ! On the more serious side, thanks for all =
of your=20
input to the list. As a fairly new member, I find the information =
exchage to be=20
interesting and informative. Thanks for the encouragement as =
well.


 


Have a great day !


 


Ron


 


From: "Ron Horton" 
Subject: Cultural Exchange
Date: Wed, 16 Sep 1998 19:23:54 -0000

Meredith,

Thanks for sharing your knowledge and humor of cultural exchange =
programs, and your help and encouragement to all. If you ever do want to =
participate in any cultural exchange programs here in Texas let us know. =
I'm sure we can arrange for memorable activities. Ha ! Have a great day =
!

Ron









Meredith,


 


Thanks for sharing your knowledge =
and humor of=20
cultural exchange programs, and your help and encouragement to all. If =
you ever=20
do want to participate in any cultural exchange programs here in Texas =
let us=20
know. I'm sure we can arrange for memorable activities. Ha ! Have a =
great day=20
!


 


Ron


From: "Ron Horton" 
Subject: RE: Cultural Exchange
Date: Wed, 16 Sep 1998 19:35:20 -0000

Meredith,

Thanks for sharing your knowledge of cultural exchange programs, your =
sense of humor, and your help & encouragement. It is all appeciated. =
Have a great day.

Ron









Meredith,


 


Thanks for sharing your knowledge of cultural =
exchange=20
programs, your sense of humor, and your help & encouragement. It is =
all=20
appeciated. Have a great day.


 


Ron


From: "Ron Horton" 
Subject: test
Date: Wed, 16 Sep 1998 22:31:03 -0000

Just a test. My ISP has been flakey lately. Sorry.










Just a test. My ISP has been flakey =
lately.=20
Sorry.


 


From: S-T Morrissey 
Subject: VRDT electronics
Date: Sat, 19 Sep 1998 16:44:17 -0500 (CDT)

Ron,

Thanks for your interest in the VRDT electronics. If it would 
help you any with your CAD update, I have kermitted my CAD originals
in to the University and posted them as .. .DXF versions at:

http://www.eas.slu.edu/People/STMorrissey/etc_export/tilt2osc.dxf
and ..../tilt3dmd.dxf

I think they can be FTP'd from there. I don't have the software to
convert the .dxf to HTML.

Regarding your questions:
The circuit card is the oscillator as drawn. (make sure you have a
corrected version of the schematic: I originally had the common pins
of the Statek and the 4047 reversed.) I did some additional touching
up of the drawings today before I sent them in.

The DC input power supply filter is the 100 ohm resistors and a handy size
(10uf to 47 uf) tantalum capacitor. The 100 ohm r's also serve as fuses.

The oscillator(s) run at 8x of the desired output: 5khz for 625 hz (the
5khz is a Statek option), or 40khz for 5 khz output.
The tradeoff in frequency seems to be that 5 khz is considerably more
sensitive to the reactance change caused by the vane movement,
but, because of the transformer inductance, there is considerably
less current in the coils. Also, a high frequency makes the VRDT
sensitive to all the stray capacitances (eg cables) that are
sensitive to movement and temperature. I have found that the 625 hz
(a selected output of the STATEK quartz oscillator) gives about
the same sensitivity V/V for the VRDTs with 200 or 500 ohm (DC Res)
coils. The 500 ohm coils I found in a surplus store, and fitted them
with the core laminates from the TL019 transformer.

For comparison with an available low-power commercial osc/amp/demod,
the Validyne osc/amp/demodulator uses 5hkz; their embeded inductors
are quite small; they use regulated supplies, the CD4047, and Mosfet
drivers. For the tiltmeters, as we worked to increase the
thermal noise immunity, we found that lowering  the frequency
by 10 decreased the direct thermal noise by about the same amount.
We eventually used the STATEK oscillator because of some residual
frequency dependence of both the sensitivity (even with an electrolytic
bridge) and the null position; this will also be the case with the VRDT.
It is important that both the frequency and amplitude be very stable,
which is why I use the LM136AH voltage reference for both the 
oscillator and the sine converter. There is still a thermal problem
with the DC resistance of the coils themselves, which is why they
should be very closely matched.
For a personal seismograph, using silicon diode Vrefs and the CD4047 
may have to suffice.

I have yet to optimize the output amplifier for the 200 ohm VRDTs;
it should have a lower output impedance transformer, as noted.

For the bridge amplifier and demodulator: I will try to draw up 
the configuration of the connections to the VRDT with all the details. 
There are many trade-offs to be considered.  Currently I am using the 
625 hz frequency, 2k bridge resistors, the TL021 transformer coils, 
and getting about 100 millivolts/micron. The bridge amplifier has 
considerably more gain than needed.  If the gain is too high, the 
transducer is difficult to calibrate, since it limits at +-7 volts, 
or +- 70 microns. It may be desirable to use lower gain for the low 
output, and more gain in the follower.  The feedback transfer function 
needs about 1000 mv/micron.

Regards,
Sean-Thomas

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From: Jim Hannon 
Subject: Re: Eddy current sensor
Date: Sat, 19 Sep 1998 20:22:04 -0500

barry lotz wrote:

> 
> PS  Jim- I thought the VRDT was more like the plate arrangement of the
> SG. I didn't see where a coil/inductance was involved. Can you
> elaborate.
> 
Barry,

Mechanically the VRDT is like the SG moving vane arrangnment. In that
there is a moving vane between two fixed objects.  The VRDT uses
inductors (coils) that change inductance depending on the distance
between the vane and the inductor. The inductors are connected in a
bridge circuit with two resistors forming the other legs of the bridge.
Any unbalance in the inductance of the two inductors causes an output
voltage of the bridge. Since the bridge is excited with AC one can tell
the direction of unbalance by the phase of the output voltage. Sean uses
audio transformers as the inductors in the STM-8. Removing the
laminations from one end of the coil allows the vane to complete the
magnetic path thereby increasing the inductance as the vane moves
closer. I am working on a very tiny VRDT that uses ferrite pot cores for
the sensors.

Hope this helps.
-- 
Jim Hannon
http://soli.inav.net/~jmhannon/
42,11.90N 91,39.26W
WB0TXL


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From: "Ron Horton" 
Subject: Multiple messages
Date: Sat, 19 Sep 1998 20:48:29 -0000

Sorry for the multiple messages. My e-mail was not functioning properly. =
I kept getting messages that my e-mails were not being received.  Ron.









Sorry for the multiple messages. My =
e-mail was=20
not functioning properly. I kept getting messages that my e-mails were =
not being=20
received.  Ron.


From: robert barns <75612.2635@..............>
Subject: Measuring deflection
Date: Sun, 20 Sep 1998 11:12:23 -0400

Nick & Sophie,
  Using a magnetic core for your coil will certainly result in a
seismometer with very nearly zero sensitivity.  When placed near the
magnet, the attraction will esentially lock the boom at one point.  A
non-magnetic bobbin (or coil form) is required.
  The choice of the best material for the suspension wire on a Lehman was=

discussed extensively on this net recently.  I think that there was fairl=
y
general agreement that piano wire (high tensile strength seel wire) is th=
e
best.
  You can buy a steel guitar (high E) string at your local music store
(probably have to buy a whole set of 6) but this may be too short to be
convenient.
  I used 0.012" dia. piano wire (which has a yield strength of about 34
lbs.) in my Lehman and it has been fully satisfactory.  I have a large
quantity of many sizes of piano wire (I once contemplated re-stringing on=
e
of my pianos) and I would be happy to mail you (no charge) a more than
adequate length of this if you will supply your mailing address (I don't
know how to send it by e-mail).
Bob Barns

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From: barry lotz 
Subject: Re: Eddy current sensor
Date: Sun, 20 Sep 1998 08:28:18 -0700

Jim
   Thanks
   Barry


>Jim Hannon wrote:
> 
> Mechanically the VRDT is like the SG moving vane arrangnment. In that
> there is a moving vane between two fixed objects.  The VRDT uses
> inductors (coils) that change inductance depending on the distance
> between the vane and the inductor. The inductors are connected in a
> bridge circuit with two resistors forming the other legs of the bridge.
> Any unbalance in the inductance of the two inductors causes an output
> voltage of the bridge. Since the bridge is excited with AC one can tell
> the direction of unbalance by the phase of the output voltage. Sean uses
> audio transformers as the inductors in the STM-8. Removing the
> laminations from one end of the coil allows the vane to complete the
> magnetic path thereby increasing the inductance as the vane moves
> closer. I am working on a very tiny VRDT that uses ferrite pot cores for
> the sensors.
> 
> Hope this helps.
> --
> Jim Hannon

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From: Clark Wockner 
Subject: Re: Measuring deflection
Date: Sun, 20 Sep 1998 11:31:33 -0500

Hi to all:
    I am in the process of building a new layman.   I want to improve the
sensitivity and am doing things differently than on my old original Layman.
My old unit has a 7 lb. mass and the boom is made of 1/4 inch make bolt.   The
new one has a 22 lb. mass and a 5/16 inch boom.  My question to all.  Has any
one tried making a boom suspension mechanism out a solid rod with a yoke on
the upper end to replace the piano wire commonly used in Layman's.  Piano wire
stretching must introduce vertical component into the recording.    I would
think a yoke on the upper end with a ball bearing running in compression on a
polished bolt would provide a a solid suspension for the mass without inducing
any vertical component into the recording.  ( I have  forgotten whose idea it
was for the ball bearing but it sounds good to me.)   Does anyone have any
other method of keeping the vertical component out of the picture?
    Living in  a Seismic no mans land like Illinois,  one needs all the
sensitivity one can get.

Thanks,  Clark Wockner


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From: S-T Morrissey 
Subject: Lehman suspension
Date: Sun, 20 Sep 1998 12:38:14 -0500 (CDT)

Clark and all the Lehman fans:
(this is an update of a previous post)

I have seen enough of your problems with the design of the
hinges for the Lehman horizontal, what with razor blades,
oil burner nozzles and ball bearings (which have considerable
friction compared to the small torques seismometers need to be
sensitive to, which is why they are often immersed in oil when
used in machinery), so I am presenting a well proven option, 
namely the design that has been used in the WWNSS (World Wide 
Network of Standard Seismographs) for the Long Period Horizontal.
The seismometer is the Sprengnether S-5000H, which hasn't been 
produced in decades, but probably a hundred are still in use.

I have scanned a drawing of the details of the lower
and upper hinges to my web page labeled ... PSN info...
at:
http://www.eas.slu.edu/People/STMorrissey/index.html

Hopefully this simple taught-wire arrangement will
simplify the problems with hinges. IN fact, the overall
design of the seis can easily be copied. If there is
some interest, I will take a photo of one of 4 that
I am still operating and post it.

The suspension yoke wires that fasten to each side of the
mass are large, like 0.025 (#22) to 0.050. (Use 16 gauge 
stainless steel electric fence wire). The actual hinge at the top,
from the yoke saddle clamp to the frame upright, is about 0.015 wire,
(#26: use Guitar B string at 0.016) about 5mm long, as is the 
hinge at the bottom, from the forked support at the end of the 
boom to the frame. Notice how the fork arrangement reverses the
force of the boom so the suspension is under tension. The mass 
is 11 kg, or about 25 pounds.

Regarding the question of vertical movement of the horizontal
mass: it will be present, but the coil-magnet velocity 
sensor is only sensitive to axial motion of the coil in the 
magnet, so does not sense vertical motion. Because there will
be some vertical movement of the coil (it actually swings in
a very shallow arc, and there are thermal effects), sufficient
clearance of the coil in the magnet is necessary.

(Clark, if you are ever close to St. Louis, invite yourself in
for a visit to the seismological laboratory at St. Louis U).
(my phone is 314 977 3129).

Regards,
Sean-Thomas

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From: S-T Morrissey 
Subject: VBB oscillations
Date: Sun, 20 Sep 1998 13:09:00 -0500 (CDT)

Barry,
A quick answer regarding your VBB configuration. It is important
to know the sensitivity of your displacement transducer to
use the Mathcad model of the transfer function. The resulting
response quite accurately reflects what you get, as I have 
previously shown in the calibration data.

The transfer function will indicate an oscillator if either
end of the flat velocity response has an inflection in it.
If the damping term zeta is much less than 0.6, the oscillation
will be at the effective period, like 20 to 100 seconds,
depending on your configuration. If the response has a bump
at the short period end, several instabilities are possible
due to "out of range" selection of the feedback components,
like the value of Cp is too large or r is too small or too 
large. The response should be quite flat.

To determine the actual value of r, the gain(s) of the displacement
amplifier(s) need to be known; this is readily determined from
the elements in their feedback per your schematic. Like for one
of the VBBs here, the transducer is 58mv/micron, the first amp 
is x3, the second is x10, so the value used in the Mathcad
function (which uses MKS units) is 1 740 000 volts/meter.
(1.74 million V/m sounds hugh, but it is a reality of the VBB).
My transfer function response indicates an oscillation at 300-400hz, 
which I can hear, but I killed it with appropriate low-pass filtering
in the 2nd X10 displacement amp. I also use a low-Z filter at
the demodulator output, like 1k ohms with 4 ufarad, (NP of course).

Regards,
Sean-Thomas

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From: "Rex Klopfenstein, Jr." 
Subject: Re: VRDT electronics
Date: Sun, 20 Sep 1998 15:01:54 -0400

Thanks for the help, this should keep me out of trouble for a while!

> Thanks for your interest in the VRDT electronics.

Rex Klopfenstein, JrBowling Green, OH


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From: Larry Cochrane 
Subject: Re: Radio-Controlled Clock
Date: Sun, 20 Sep 1998 13:22:43 -0700

Barry,

SDR does not need continuous reception to WWV or WWVB to work. The longer
the better, but if you can get a few hours of data SDR will be able to keep
the time fairly accurate during the times of no signal.

-Larry Cochrane
Redwood City, PSN 


At 09:24 PM 9/18/98 -0700, you wrote:
>Karl
>    I was wishing to include the clock in my system but was having
>trouble with the receiving signal. It is not always received or is
>intermittent. The Radio Shack unit checks the time at early morning
>hours for better success. Do you have a way of checking for errors in
>the incoming data or time intervals?
>                                                     Regards
>                                                     Barry


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From: Clark Wockner 
Subject: Re: Lehman suspension
Date: Sun, 20 Sep 1998 19:21:16 -0500

Sean-Thomas:
    Thanks very much for posting the drawings of the Sprengnether S 500H
seismometer hinges.  This will solve many problems for me.  It looks
fairly simple to duplicate.
Thanks again,   Clark



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From: barry lotz 
Subject: Re: Radio-Controlled Clock
Date: Sun, 20 Sep 1998 18:57:08 -0700

Larry
   I evidently get enough reception for Radio Shack. Their data
indicates if the clock is updated in the last 4 days or so it doesn't
display a poor reception symbol. I have always had an ok signal
identification. Sometime in the in the early morning the reception must
be ok or good. My "problem" is I am not currently using a color monitor
and therefore SDR on the 386 being used. I also am checking a FFT
triggering routine I wrote. Therefore I need to include the timing logic
in my program. I will eventially get the sub thought out and
incorporated but am still working on the flow diagram to consistantly
detect the 800ms frame at the top of the minute.
                                                 Regards
                                                   Barry
   
Larry Cochrane wrote:
> 
> Barry,
> 
> SDR does not need continuous reception to WWV or WWVB to work. The longer
> the better, but if you can get a few hours of data SDR will be able to keep
> the time fairly accurate during the times of no signal.
> 
> -Larry Cochrane
> Redwood City, PSN
>

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From: "David A. Nelson" 
Subject: seismo  station maps  updated
Date: Mon, 21 Sep 1998 21:00:25 +1200

 hi all,
              sorry for the delay,    have been really busy over the last 2
months

   the Calif. and USA PSN station maps are finally updated  with the 4 new
additions.....

    Walt Williams, Canoga Park,   Calif

   Michael Layman,  Corpus Christie,  Texas

  John Cole,  Pearland,   Texas

  Ron Horton,  Houston, Texas


   An  Official (smile) welcome  to the group guys    thanks for passing ur
station info  on to me  fo addition to the map and database.

  OHHHH    please note  !!!!

  the database is now in 2 parts  as  windows notepad  got to its file size
limit.

  stations  1    -    49   are   in   people.htm
  stations  50  - >>      are in    people1.htm

  now  when accessing  station data  the ur www browser  will automatically
select the appropriate  file
but  if u are wanting to   take copies of the full database u need to be
aware that its in 2 parts

   there will be  2 new New Zealand  stations  added in the near future too
 both in the North Island,  the first ones operating up there.
one in Welling city  at the sthrn end of the island, the other in  Taupo  i
nthe middle of the Volcanic region.  Both are in high schools.

   cheers  all

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


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From: "Rex Klopfenstein, Jr." 
Subject: VBB Oscillator Questions - II
Date: Mon, 21 Sep 1998 12:53:06 -0400

S-T Morrissey
I have downloaded your schematics and that really helps.  When my
printer tries to print the graphics from your page, a lot of detail is
lost!  Also, your post gives some real helpful information.

I do have a few questions.

First, I take it that the absolute value of the oscillator frequency is
not critical as long it is stable in frequency and amplitude (and near
the 5 or 40KHz)?

The other question has to do with components in the oscillator.  What is
the size of the individual polarized capacitors used to make the
non-polarized capacitor?  Are the capacitors 10 mfd each or constructed
from two 20mfd's so the total capacitance is 10 mfd.

What is the value of the resistor connects to on side of the transformer
primary and labeled "(0-30)(5khz)"?

When I get these changes made and put a components list together, I will
post the partial schematic on my webpage (as a .dxf file) to be reviewed
and checked.  I will post information on this list when I get everthing
set.  I am now working on the Bridge/Demod/Filt circuit.

Rex Klopfenstein, Jr
Bowling Green, OH



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From: Nick & Sophie Caporossi 
Subject: Re: Measuring deflection
Date: Mon, 21 Sep 1998 16:59:33 -0400


Karl "Station #40"
 Thanks for your explanation on the natural frequency of a "garden gate"
Lehman seismograph. It seems that I have some major revisions to make. It
is time to make a more stable base, perhaps using angle irons. Need to
rewound the coil on a non metallic core. Some of the other designs which
members suggested for the horizonal and vertical hinge points will have to
be considered. Will also have to get rid of the fishing line and use a
steel or guitar wire as recommended be Bob Barns.

 Again thanks for your help
Nick  

At 10:27 AM 9/18/98 -0700, you wrote:
>Nick --
>
>The Lehman (or "garden gate") design is simulating a very long pendulum,
>which has a natural period -- the time it takes the mass to swing over and
>return to its original position. 

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From: S-T Morrissey 
Subject: Re: VBB Oscillator Questions - II
Date: Mon, 21 Sep 1998 17:23:25 -0500 (CDT)

Rex,
Your SASE arrived today. Do you still need hard copies of the
schematics? I assume that downloading the .dxf files served
up all the details you need. I have made a preliminary drawing
of the VRDT connections; I will finish it and post both the .dxf
and a scanned copy, as well as new scans of the revised schematics.
I will try to double the resolution at the expense of creating
larger .gif files. Maybe someone can suggest a better format for
line drawings. I don't have any info on how many people can
use the .dxf files. I use a subset of autoCAD called autoSKETCH
which is not very expensive compared to the full AutoCAD package.
It is quite old (pre-internet) ; an upgrade might actually write 
..html files.

Your questions:
The frequency itself needs only to be approximate, but stable,
especially in amplitude. I still haven't determined whether the
600 hz or 5 khz should be preferred for the VRDT.

The back-to-back electrolytics in the coupling from the sine
converter to the output filter are 10uf each or greater.
The 30 ohm resistor from the low side of the transformer primary
to common is for properly matching the impedance, and should
equal the transformer impedance (600 ohms) divided by the gain
(where 100k/5.1k = 20), so 600 / 20 = 30 ohms.

They are also used in the secondary gain loop of the AC bridge amp 
where they are 10uf each, or greater. They prevent the amplifier 
from having a high DC gain. I should probably also add capacitors
to the input of the amplifier to prevent it from having any
DC gain at all. When it is used with the electrolytic tiltmeters,
large non-polarized capacitors are installed at the bridge 
itself to keep any DC out of the bubble, so it was AC coupled.

I have the artwork for both PC boards if you want to try to
print your own. It is 2x, with black lines, so would have to
be reduced and reversed. Our copier can do the reduction to
a transparency that can be used to make a negative with 
contact film. Maaybe there is a copier that can reverse an
image. But somewhere along the line I will redraw to PC artwork 
so it is all one board specifically for the VRDT.

regards,
Sean-Thomas

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From: "Rex Klopfenstein, Jr." 
Subject: Re: VBB Oscillator Questions - II
Date: Mon, 21 Sep 1998 19:08:46 -0400



S-T Morrissey wrote:

>
> I don't have any info on how many people can
> use the .dxf files. I use a subset of autoCAD called autoSKETCH
> which is not very expensive compared to the full AutoCAD package.
> It is quite old (pre-internet) ; an upgrade might actually write
> .html files.

I am actually using AUTOCad 14.  I am note using anything special in my
drawings so any program that accepts .dxf files should have no problems.
I also remember a utility program that came with Netscape that translates
autocad files into web files (not sure of the format).  I will investigate
and maybe use when I post by schematic.


Thanks

Rex Klopfenstein, Jr
Bowling Green, OH



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From: Nick & Sophie Caporossi 
Subject: Re: Measuring deflection
Date: Tue, 22 Sep 1998 08:41:11 -0400

>Date: Mon, 21 Sep 1998 16:59:33 -0400
>To: PSN-L Mailing List 
>From: Nick & Sophie Caporossi 
>Subject: Re: Measuring deflection
>
>
>Karl "Station #40"
> Thanks for your explanation on the natural frequency of a "garden gate"
Lehman seismograph. It seems that I have some major revisions to make. It
is time to make a more stable base, perhaps using angle irons. Need to
rewound the coil on a non metallic core. Some of the other designs which
members suggested for the horizonal and vertical hinge points will have to
be considered. Will also have to get rid of the fishing line and use a
steel or guitar wire as recommended be Bob Barns.
>
> Again thanks for your help
>Nick  
>
>At 10:27 AM 9/18/98 -0700, you wrote:
>>Nick --
>>
>>The Lehman (or "garden gate") design is simulating a very long pendulum,
>>which has a natural period -- the time it takes the mass to swing over and
>>return to its original position. 

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From: Nick & Sophie Caporossi 
Subject: Testing ?
Date: Tue, 22 Sep 1998 08:47:26 -0400

There seems to be something amiss. My mail is not being delivered.
 Nick

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From: S-T Morrissey 
Subject: baseplate material
Date: Tue, 22 Sep 1998 11:32:08 -0500 (CDT)

Nick,

I am concerned about your suggestion to use "angle iron" for
the baseplate of your seismometer. Since seismometers generally
use coil-magnet transducers, ferrous materials have generally
been avoided in any other part of the sensor. Any peripheral
magnetic fields will be enhanced by iron materials and induce
unwanted voltages into the coil or transducer.

Since it is so easy to work with, and available in many shapes,
aluminum is generally preferred, although non-magnetic stainless 
steel is also used for the base and frame. I would also suggest that
aluminum channel 1" x 1" x1" x 1/8" thick should also be used
for the boom, unless you can find brass or stainless threaded
rod; I would not use steel rod. All the hardware should also be
stainless steel; Home Depot or HQ has an excellent selection.

My experience with baseplates has been mostly in the realm of
tiltmeters, which are horizontal seismometers by another name.
In this regard, thicker is better, with even the smallest designs
using 1/2" aluminum plate.

For the vertical VBB sensor here, a base/frame made with aluminum
channel and angle material 1/8" thick is adequate. This is because
everything is moving in a vertical plane, not torqueing the base.
When I use the same structure for a horizontal, it is not rigid 
enough, since the movement is across the plane of the base, 
including the centering adjustment which is applied to one corner.
Even the slightest rotation or twisting of the base will 
affect the alignment of the transducers.  So I use 1/2" aluminum 
plate (from McMaster Supply) under the inverted channel+angles 
of the base frame. I drill holes through both to fasten the seis 
components.

I can also suggest that if the trip to the metal scrap yard yields
a piece of aluminum baseplate that needs to be cut or squared up,
I have been using a fine-toothed CARBIDE tipped table saw blade 
and a similar miter saw blade (60 teeth/10") to cut aluminum.
THey make clean (shiney) cuts; please use all precautions, though.
The "piranna" curve of the teeth can make them prone to gouge 
into aluminum and throw it at you; always clamp the pieces.

Regards,
Sean-Thomas


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From: Jim Hannon 
Subject: Re: baseplate material
Date: Tue, 22 Sep 1998 15:50:05 -0500

S-T Morrissey wrote:

> I can also suggest that if the trip to the metal scrap yard yields
> a piece of aluminum baseplate that needs to be cut or squared up,
> I have been using a fine-toothed CARBIDE tipped table saw blade
> and a similar miter saw blade (60 teeth/10") to cut aluminum.
> THey make clean (shiney) cuts; please use all precautions, though.
> The "piranna" curve of the teeth can make them prone to gouge
> into aluminum and throw it at you; always clamp the pieces.
> 
> Regards,
> Sean-Thomas
> 

My experience with cutting aluminum with a table saw is that you need
"full body protection" when cutting. I wear a denim jacket, eyeglasses,
a full face shield and gloves. The metal chips are very sharp and one in
your eye would cause serious injury.
-- 
Jim Hannon
http://soli.inav.net/~jmhannon/
42,11.90N 91,39.26W
WB0TXL


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From: johnccole@........ (john c cole)
Subject: Re: Thanks
Date: Thu, 17 Sep 1998 00:53:41 -0500

meredith
  ron and i are both  thankful to have a good friend like frank cooper 
to show us the way. frank has been more than generous with his time and
materials. we also appreciate this net and the members  who supply us
with technical information. gentlemen, do you know how important that is
to the novice? 
  the reason for the bountiful harvest  is the hard working gardener..

                                                     your friend john c
cole w5auh

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From: johnccole@........ (john c cole)
Subject: Re: baseplate material
Date: Tue, 22 Sep 1998 17:03:47 -0500

sean
  i have been reading your mail . the advice that was give as to the
upper and lower hinges were right on . i personally have two leahman long
wave detectors that operate great using a ball bearing . could it be
better?  absolutely. as an amateur we have to start somewhere. i will
modify these detectors shortly.
   we all appreciate your input and help in the construction of our
equipment. there are a lot of new kids on the block that are listening 
and can use the advise.
                                                          john w5auh

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From: "Al Allworth" 
Subject: RE: baseplate material
Date: Tue, 22 Sep 1998 22:09:49 -0700



> -----Original Message-----
> From: Jim Hannon [mailto:jmhannon@.........
> Sent: Tuesday, September 22, 1998 1:50 PM
> To: PSN-L Mailing List
> Subject: Re: baseplate material

Hi Jim and all,

I have 2 suggestions concerning the cutting of aluminum on a table saw.

1.  Get a smaller pulley for the motor on the table saw, about the same size
as on the arbor.
    This gets the tooth speed down to where the aluminum isn't being melted
at the tips of
    the teeth while cutting. It doesn't stick to the teeth as bad and get
thrown around the
    room wit as much force. Waxing the blade with paste wax also produces a
nicer cut.

2.  Have a blade ground for cutting aluminum. The angle on the tip of the
teeth is different.
    Most towns have someone doing carbide blade sharpening. I saw an add
recently for sharpening
    for .50 per tooth. If you have a blade that is getting dull, this would
be a good investment
    for your shop, just get it resharpened but at the different angle.

There is a paste wax made for use in machine shops that comes in a stick.
You just touch the stick against the blade while rotating before each cut.
Regular paste wax works OK but must be applied with the power OFF. Apply to
both sides and the tips of the teeth.

Use a push stick when cutting smaller pieces. It is a stick with a notch in
the ent so that it can push both forward and down. You  should probably make
two, one for each hand. Also don't stand directly behind the saw, stand off
to one side.

It is dangerous to try to use a Skill saw for cutting aluminum.

Keep in mind: It's awfully hard to build seismometers only with one hand.

						Al Allworth




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From: Nick & Sophie Caporossi 
Subject: Re: baseplate material
Date: Wed, 23 Sep 1998 18:14:20 -0400

Sean-Thomas:
At 11:32 AM 9/22/98 -0500, you wrote:
>Nick,
>
>I am concerned about your suggestion to use "angle iron" for
>the baseplate of your seismometer. Since seismometers generally
>use coil-magnet transducers, ferrous materials have generally
>been avoided in any other part of the sensor. Any peripheral
>magnetic fields will be enhanced by iron materials and induce
>unwanted voltages into the coil or transducer.
>

 Thanks for the tip about not using Iron on the base and frame. 
Since I intend to make a few seismometers, the next seis. will be made of
all aluminum.  I am using Iron only on the frame and the vertical post for
this current one. The Magnet and coil will be about 6 inches away from any
iron. 

>for the boom, unless you can find brass or stainless threaded
>rod; I would not use steel rod. All the hardware should also be
>stainless steel; Home Depot or HQ has an excellent selection.

 I am using stainless steel for the boom.  

>For the vertical VBB sensor here, a base/frame made with aluminum
>channel and angle material 1/8" thick is adequate. This is because
>everything is moving in a vertical plane, not torqueing the base.

 A few weeks ago I sent you a message, requesting information on a leaf
Spring Broadband Seismometer and also sent a self addresses envelope. I
mailed it to "sean@..........."  The message read as follows:

>>Hi Sean-Thomas:
>>A job well done. I went to your web site and it is full of very
interesting >>information. I like to try my hand at making a leaf spring
Seismometer.
>>Please send me information on making a Homemade leaf springroadband
>>Seismometer. A 9" x 11" SASE with 5 32cent stamps on it, is on it's way. 
>>I have downloaded some of your some of your photos. They are chuck full
of >>information. 

>>Been following the correspondence between the members of PSN-L quake.net
for last >>couple of years.  You and other members are quite knowledgeable
in the field of >>Seismology.

>>Nicholas Caporossi, nickcap@.............

 Thanks I can use any help I can get.
Nick


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From: "Rex Klopfenstein, Jr." 
Subject: VBB Schematics
Date: Wed, 23 Sep 1998 20:33:20 -0400

Well, I have just posted my schematics for Sean T. Morrissey's Sine Wave
Oscillator.  Go to http://www.wcnet.org/~klopfen and follow the links.
These should be exact copies of Sean's circuits other than the physical
placement of components on page.

I have a link that will download a .dxf format file which is the
schematic.  A parts list can be viewed on linked page.  See page for
info on mailing copies.  I am looking for a better way to post
drawings.  About all can do is scan in hardcopy and post.  I'll try this
latter tonight.  It may be hard to print out though!!

I would appreciate it if all could review and send me comments.  I have
just started drawing the bridge amplifier.  Sean is suppose to post the
wiring scheme for the VRDT transformers and how they attach to the
oscillator and bridge.  My goal is to complete a schematic of the entire
VBB seismometer on one 36"x24" sheet with components list.

There is several things that I would like to comment on the sine wave
oscillator circuit and parts list.  I am not sure of the type of
capacitor that should be used for what I have labeled as C6 (on output
of voltage reference).  Even though a 10-15 turn potentiometer seems to
be easier to adjust, I find that single turn pots are easier to adjust
because they don't jump in resistance when the screwdriver is removed
(maybe just a personal preference!!).  I also have a question on the
wiring for the 4047.  I have the spec sheet and they show that pin 6
should be connected to 5v instead of ground for free-running mode, maybe
a typo error in spec sheet?

By the way, I tried to locate information on the Statek Oscillator
#PXO-1000.  Statex has discontinued this model and suggested Epson.  I
have requested a catalog but need the specifications for the PXO-1000 to
find a cross!

Please check and comment!!!

Rex Klopfenstein, Jr.
Bowling Green, OH



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From: "Rex Klopfenstein, Jr." 
Subject: Re: VBB Schematics
Date: Wed, 23 Sep 1998 22:03:13 -0400



Rex Klopfenstein, Jr. wrote:

>  Well, I have just posted my schematics for Sean T. Morrissey's Sine Wave
> Oscillator.  Go to http://www.wcnet.org/~klopfen and follow the links.

 The link should read: http://www.wcnet.org/~rklopfen



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From: S-T Morrissey 
Subject: VRDT oscillator frequency
Date: Wed, 23 Sep 1998 22:21:58 -0500 (CDT)

Rex,

You must have come up with some pretty poor multi-turn
potentiometers, or that giant craftsman screwdriver needs
replacing. The whole advantage of multi-turn over single turn is 
greater resolution and stability. Like a 720 ohm, 20 turn
pot is only 36 ohms/turn, or 0.1 ohm per degree,  whereas the 
single turn 720 ohm is 2 ohms /degree (if it went 360 deg.).
And the manufacture of the multi-turn pots usually produces a 
linear element, often made of a thermally stable ceramic,
which is much more difficult with a circular element.

Your questions:

The capacitor on the output of the voltage reference can be
any handy value.

I don't think that the crystal oscillator is necessary if proper
components are used with the 4047, like a polyester film capacitor
at pin 2. I just checked the PC board again, and pin 6 is grounded.

I have almost finished the drawing of the VRDT connections, and 
will try to post it tomorrow or Friday.  I had to crawl into the
cave in the Ozarks today to change the desiccants in the electronics
that support the STS-1 based system. ( some photos are linked from the
IRIS page of my site).

I have also considered the oscillator frequency question and gathered
this information:

a:	The inductance of the VRDT when made with the TL021 transformer 
with the vane centered in a 2mm gap is 125 millihenries (per side). 
This calculates to an impedance of 3.9k ohms at 5khz, and 470 ohms 
at 600 hz. This would be the effective bridge impedance.

b:	With the borrowed digital LCR meter, I measured the inductance
change as the vane is moved with the micrometer. Of course one side
increases as the other decreases, so I summed the changes. They
average 70 micro-henry per micron. This is a change of the reactance 
of 2.26 ohms per micron at 5 khz, but only 0.27 ohms at 600 hz. 
Clearly the 5 khz (or even higher?) frequency gives much more sensitivity.

c:	The 600 hz option is used for the tiltmeters because it greatly
reduces reactive changes caused by temperature, etc, of the long
(over 10 meters) cables that are used. For the seismometer, the 
bridge can be within a few cm of the VRDT, so this is much less a problem.
(Also, the tiltmeters are electrolytic resistive bridges, whose 
output was not frequency dependent.) 

d: As long as the bridge excitation is a clean sine wave, without
high frequency harmonics, reactive changes should be minimized.
I have noticed that the Validyne waveform is 'a mess", and 
considerable DC offsets can be produced in the VRDT output just
by touching the ribbon cable that I use.

e:	SO... It looks like the sine frequency should be 5 khz.
This makes the bridge impedance 4.02k ohms (at 1%), which is 
what it was designed for, and how I have drawn the schematic.

f:	I have still not considered whether a different transformer
is needed at the output of the oscillator. It may be necessary
if one oscillator is used to drive 3 VRDTs in a three-component
system; one oscillator is used to drive both components of the
biaxial titlmeter.

Regards,
Sean-Thomas

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From: "James M Hannon" 
Subject: Re: VBB Schematics
Date: Thu, 24 Sep 1998 09:22:11 -0500



Rex,
DigiKey has a large selection of Oscillators including the Epson parts.
Look in their online catalog at http://www.digikey.com/ They do have the
Epson parts with built in divider but they are $20 each. If you want
crystal control I would get one of the higher fixed frequency oscillators
for less than $5 and add an external cmos divider chip. You might also be
interested in looking at http://soli.inav.net/~jmhannon/driver.html for my
approach to driving the VRDT .

Jim Hannon






"Rex Klopfenstein, Jr."  on 09/23/98 07:33:20 PM

Please respond to PSN-L Mailing List 

To:   PSN-L Mailing List 
cc:
Subject:  VBB Schematics



By the way, I tried to locate information on the Statek Oscillator
#PXO-1000.  Statex has discontinued this model and suggested Epson.  I
have requested a catalog but need the specifications for the PXO-1000 to
find a cross!

Please check and comment!!!

Rex Klopfenstein, Jr.
Bowling Green, OH












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From: S-T Morrissey 
Subject: Re: VBB Schematics
Date: Thu, 24 Sep 1998 19:22:53 -0500 (CDT)

Rex,
I just checked your site. I guess you haven't had time to scan
the schematic. I don't want to retrieve the .dxf file yet, since 
we have to jump over several firewalls to get it from an external
server to a useful location. (the U is paraniod about hackers).

I looked at the parts list. I will try to be more specific about
the parts specifications, like 1% or capacitor construction. Much
of the schematic material is from old pencil notes that are often
marked up inconsistently. You saw my comments about multi-turn
pots, which are necessary for low noise and long term stability.

I think that the transformer will remain the 600-600 ohm TM016,
since it looks like 5khz will be a better excitation frequency
for the seismometer.

I was going to scan the VRDT interconnection but I found some
more editing to do first. Tomorrow ....

Regards,
Sean-Thomas

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From: S-T Morrissey 
Subject: Re: mini vbb noise
Date: Thu, 24 Sep 1998 19:53:00 -0500 (CDT)

Barry,

If you are looking for teleseisms recently, there has not been much
to record. The 30-second surface wave you saw was from a 6.3 in the
SW pacific. The smaller the sensor, the more it is susceptible to
thermal noise, especially if the MTQ (mass*period*Q) product is small, 
so the better it has to be insulated. I made a thermal
shell with a 3-gallon flower pot with 3 layers inside and out of
1/2" reflectix insulation, and it dropped the noise from the broadband
geophone by a factor of 10. Another noise that varies markedly from
day to night is barometric; the daytime is rich in thermal heating/
bouyancy effects making plumes in the atmosphere. These particularly
effect a vertical, especially if the mass is not real dense. Only
a good pressure containment can eliminate them.

Today the noise picture here is dominated by the 6-second microseisms
from the hurricane. They increased in amplitude by about 50 X in 
the last 15 hours or so, and will probably get worse.

But we need whomever is holding off the interesting earthquakes
to "quit it out" so we can evaluate our creations.

Regards,
Sean-Thomas

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From: Gregory Bajuk 
Subject: Your pictorial of the S5000 long-period Seis.
Date: Fri, 25 Sep 1998 12:35:39 -0700 (PDT)

Sean, 
I downloaded your pictorial of the S5000 (Columbia-Sprengnether)
horizontal seismometer that you have on your internet site.  It took me a
while to figure out how the lower hinge worked but then the light went on.
It is a simple but elegant arrangement and like you said  solves all of
the lower hinge friction problems.  Thanks for putting that pictorial on
your site.

The S5000 looks fairly compact and you mentioned it could probably be
built by amateurs like me.  Could you provide some more details of its
dimensions, length, width, height, weight.  Also is there a source for the
pictorial schematic that you have on your site?  Any information would be
helpful.  Any commercial sources for this type of seismometer?

Thanks, Greg Bajuk 


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From: Seisguy@.......
Subject: Earthquake Shakes Midwest
Date: Fri, 25 Sep 1998 16:55:20 EDT

 
Earthquake Shakes Midwest

..c The Associated Press

 CLEVELAND (AP) -- An earthquake believed centered in northeast Ohio and
ranging into at least three other states shook buildings Friday afternoon, but
there were no immediate reports of damage.

John Minsch, geophysicist for the U.S. Geological Survey in Golden, Colo.,
confirmed an earthquake of a preliminary magnitude of about 5 was felt shortly
before 4 p.m. EDT in parts of Ohio, Pennsylvania, Michigan and New York.

The quake was felt as far west as Fremont, about 75 miles west of Cleveland,
and as far south as Columbus.

``We believe it was centered at or near Ashtabula, Ohio, but we're trying to
pin that down,'' Minsch said.

He said the severity was not major. ``But it was moderate, probably enough to
knock things off of shelves, but we wouldn't expect extensive damage.''

``It was like riding on a bumpy road,'' said Steve Fought, a campaign
spokesman for U.S. Senate candidate Mary Boyle, who felt the tremor at his
office in downtown Cleveland.

Vania Stefanova, an attorney working in her office on the 19th floor of a
Cleveland office building, thought something was wrong with her desk.

``It was a jolt,'' she said.

While office workers felt the quake, several people on the street said they
didn't notice anything unusual.

Dick Patton, a radio operator at the Cleveland State Park along Lake Erie,
said he felt a ``gentle, rolling motion that kept going for about 30 seconds''
at 3:52 p.m.

``It's more of a thrill type thing than a danger,'' he said. ``People in
California would laugh at us.''

Magnitude 5 can produce moderate damage.

State officials plan to set up an earthquake monitoring network in November
that will include at least six stations around the state, said Tom Bert, a
geologist of the Ohio Department of Natural Resource's Division of Geological
Survey.

The state had 13 operating seismographs in 1980, primarily paid for with
grants from the Nuclear Regulatory Commission. But money gradually ran out.

A Cleveland network of seismographs at John Carroll University was dismantled
in 1992 when the priest who ran it went to Bolivia.

A seismograph was installed last summer by the College of Wooster. An older
seismograph at the University of Toledo can pick up only large quakes.

Geologists estimate that in the past 200 years there have been 130 Ohio
earthquakes strong enough to be felt at the surface.

AP-NY-09-25-98 1639EDT

 Copyright 1998 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: S-T Morrissey 
Subject: Ohio Quake
Date: Fri, 25 Sep 1998 17:29:08 -0500 (CDT)

Info on today's quake:

NEIS has just posted:

19:52:52   41.47N   80.48W  5 km (deep) MBlg 5.2	OHIO

The location is in northeast Ohio, near the Pennsylvania border.
There have been felt reports over many states.

Regards,
Sean-Thomas

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From: Edward Cranswick 
Subject: Re: Earthquake Shakes Midwest
Date: Fri, 25 Sep 1998 16:52:20 -0600

PSN-
    Three of us from USGS, Golden, Colorado, will be leaving early tomorrow
morning (Saturday, 26 Sep) to go to the field to record aftershocks of this
earthquake using portable seismographs.
-Edward

Seisguy@....... wrote:

>
>
>   ------------------------------------------------------------------------
>
> Subject: Earthquake Shakes Midwest
> Date: Fri, 25 Sep 1998 16:41:33 EDT
> From: AOLNews@.......
>
> Earthquake Shakes Midwest
>
> .c The Associated Press
>
>  CLEVELAND (AP) -- An earthquake believed centered in northeast Ohio and
> ranging into at least three other states shook buildings Friday afternoon, but
> there were no immediate reports of damage.
>
> John Minsch, geophysicist for the U.S. Geological Survey in Golden, Colo.,
> confirmed an earthquake of a preliminary magnitude of about 5 was felt shortly
> before 4 p.m. EDT in parts of Ohio, Pennsylvania, Michigan and New York.
>
> The quake was felt as far west as Fremont, about 75 miles west of Cleveland,
> and as far south as Columbus.
>
> ``We believe it was centered at or near Ashtabula, Ohio, but we're trying to
> pin that down,'' Minsch said.
>
> He said the severity was not major. ``But it was moderate, probably enough to
> knock things off of shelves, but we wouldn't expect extensive damage.''
>
> ``It was like riding on a bumpy road,'' said Steve Fought, a campaign
> spokesman for U.S. Senate candidate Mary Boyle, who felt the tremor at his
> office in downtown Cleveland.
>
> Vania Stefanova, an attorney working in her office on the 19th floor of a
> Cleveland office building, thought something was wrong with her desk.
>
> ``It was a jolt,'' she said.
>
> While office workers felt the quake, several people on the street said they
> didn't notice anything unusual.
>
> Dick Patton, a radio operator at the Cleveland State Park along Lake Erie,
> said he felt a ``gentle, rolling motion that kept going for about 30 seconds''
> at 3:52 p.m.
>
> ``It's more of a thrill type thing than a danger,'' he said. ``People in
> California would laugh at us.''
>
> Magnitude 5 can produce moderate damage.
>
> State officials plan to set up an earthquake monitoring network in November
> that will include at least six stations around the state, said Tom Bert, a
> geologist of the Ohio Department of Natural Resource's Division of Geological
> Survey.
>
> The state had 13 operating seismographs in 1980, primarily paid for with
> grants from the Nuclear Regulatory Commission. But money gradually ran out.
>
> A Cleveland network of seismographs at John Carroll University was dismantled
> in 1992 when the priest who ran it went to Bolivia.
>
> A seismograph was installed last summer by the College of Wooster. An older
> seismograph at the University of Toledo can pick up only large quakes.
>
> Geologists estimate that in the past 200 years there have been 130 Ohio
> earthquakes strong enough to be felt at the surface.
>
> AP-NY-09-25-98 1639EDT
>
>  Copyright 1998 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.



--
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".



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From: bzimmerman@............
Subject: Re: Earthquake Shakes Midwest
Date: Fri, 25 Sep 1998 19:27:34 -0500 (EST)


Don't laugh in CA but this quake is a major deal here.  I've been
interviewed by every major TV station and paper in the area.  Score one
for PSN.

Please send any and all recordings or information.

Ed I'd love the opportunity to meet and go out in the field with you.

By the way the quake coordinates place just this side of the border in
Pennsylvania.  80 km from my station.  Makes it the largest quake ever in
PA.


Brian Zimmerman
Dept. of Geosciences
Edinboro University of PA


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From: Edward Cranswick 
Subject: Re: Earthquake Shakes Midwest
Date: Fri, 25 Sep 1998 17:52:48 -0600

Brian-
    I am looking forward to seeing you out there and getting your advice
about what the local story is.
-Edward

bzimmerman@............ wrote:

> Don't laugh in CA but this quake is a major deal here.  I've been
> interviewed by every major TV station and paper in the area.  Score one
> for PSN.
>
> Please send any and all recordings or information.
>
> Ed I'd love the opportunity to meet and go out in the field with you.
>
> By the way the quake coordinates place just this side of the border in
> Pennsylvania.  80 km from my station.  Makes it the largest quake ever in
> PA.
>
> Brian Zimmerman
> Dept. of Geosciences
> Edinboro University of PA
>
> _____________________________________________________________________
>
> 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".



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From: Edward Cranswick 
Subject: Re: Ohio Ms5.2Lg earthquake
Date: Fri, 25 Sep 1998 17:55:40 -0600

Charlie Rond and Bob Laney-
    Thank you very much for posting your records of the event.
-Edward

Charlie Rond wrote:

> Attached is the Ohio/PA 5.2 Quake of 9/25/98.
>
>   ------------------------------------------------------------------------
>
>                       Name: 980925TA.RM1
>    980925TA.RM1       Type: unspecified type (application/octet-stream)
>                   Encoding: base64
>
>   ------------------------------------------------------------------------
>
>  Charlie Rond     -\/\--Public Seismic Network-Memphis
>                   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".



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From: Edward Cranswick 
Subject: Re: Earthquake Shakes Midwest
Date: Fri, 25 Sep 1998 18:28:04 -0600

PSN-
    Check out Brian's records at

http://coop20.geos.edinboro.edu/~brianz/seismo.html

the closest ones to the event I have so far seen.
-Edward

bzimmerman@............ wrote:

> Don't laugh in CA but this quake is a major deal here.  I've been
> interviewed by every major TV station and paper in the area.  Score one
> for PSN.
>
> Please send any and all recordings or information.
>
> Ed I'd love the opportunity to meet and go out in the field with you.
>
> By the way the quake coordinates place just this side of the border in
> Pennsylvania.  80 km from my station.  Makes it the largest quake ever in
> PA.
>
> Brian Zimmerman
> Dept. of Geosciences
> Edinboro University of PA
>
> _____________________________________________________________________
>
> 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".



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From: S-T Morrissey 
Subject: S5000 LP seis dimensions
Date: Sat, 26 Sep 1998 17:39:29 -0500 (CDT)

Greg,
 
 Looks (aka) drawings can be deceiving, as with the S5000 LP
 horizontal seis. It is actually quite large. I don't have the
 dimensions here at home, but the base is about 50 cm on a side.
 The boom is about 30 cm long (to deal with the fact that the 
 coils have to move in an arc in the magnet with minimum clearance).
 The mass is a solid brass cylinder of about 10.7 kg.

 The size could readily be reduced by about half if the coil
 clearance is dealt with. In the commercial fedback broadband
 sensors the boom is less than 10 cm long.

 The seismometer has not been made for decades. But you could send
 your interest to www.sprengnether.com; ask them for a quote! 
 They are pursuing more compact fedback designs. They may also 
 produce a version of the STM-8 leaf spring educational seis.

 As for manuals, etc, I can send (in your SASE) a copy of the 
 operating manual; unfortunately it contains little physical 
 or design information.

 Regards,
 Sean-Thomas

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From: Charlie Rond 
Subject: Re: Ohio Ms5.2Lg earthquake
Date: Sun, 27 Sep 1998 05:43:24 -0500

Edward,

>Charlie Rond and Bob Laney-
>    Thank you very much for posting your records of the event.
>-Edward

You are welcome.  Good luck with your field studies!


 Charlie Rond     -\/\--Public Seismic Network-Memphis
                  http://gandlf.ceri.memphis.edu/~rond/psn        
  


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From: robert barns <75612.2635@..............>
Subject: Re: Measuring deflection
Date: Sun, 27 Sep 1998 13:15:19 -0400

Clark,
  A 7 lb. mass should be plenty.  My current mass is about 9 lbs. and if =
I
were to build another, I think that I would use 5 lbs.
  A larger mass will require a larger dia. suspension wire which may have=

enough stiffness to cause trouble.  =

  I used 1/2" dia. aluminum rod for the boom which should be fine for any=

length boom from say 12" to 36".  This is readily avail. at hardware stor=
es
or Home Depot.  If the magnet is attached to the boom, a boom of magnetic=

material should be OK but if the coil is on the boom, the magnet will
attract a magnetic boom.
Bob Barns

Televangelists: the Pro Wrestlers of religion.

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From: "Rex Klopfenstein, Jr." 
Subject: Seimo-Watch Bulletin #98-235 Error
Date: Sun, 27 Sep 1998 13:31:01 -0400

I printed out this report of the earthquake in Ohio and noted an error!

In the paragraph where the report describes a quake on 1/31/86 and lists
a series of counties that were affected, Wood County is listed.  Wood
County is not in NE Ohio, it is located in NW Ohio just south of Toledo!

Rex Klopfenstein, Jr
Bowling Green, OH (located in Wood County)



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From: "Rex Klopfenstein, Jr." 
Subject: VBB Circuitry
Date: Sun, 27 Sep 1998 14:11:47 -0400

Sean

One comment on the selection of potentiometer types (single turn vs
multiturn).  I didn't come up with this idea myself.  I attended a
design seminar put on by Analog Devices, Burr-Brown or National (can't
remember which).  One of the speakers made the following statement:
"use a single turn potentiometer insures setting stability.  As a test,
adjust a multiturn potentiometer to desired setting.  At that time tap
the unit with a pencil and observe the results".  I tried the experiment
and sure enough, as I tapped the potentiometer the setting changed and
did not return to original setting.  The speaker blamed the stability
problems on the more complex mechanism to implement the multiturn
capability.

Now for more questions on VBB schematics

First, would a non-polarized capacitor work for the 33 mF device across
the output of the 5V voltage source in the sine wave oscillator
circuit?  It is readily available from Digi-Key or Mouser.  I have some
of the "orange-drop" capacitors (from my junk box) which would work but
they don't seem to be readily available for the popular distributors.  I
will soon place the updated schematics and parts list on my page.

I have the bridge ampifier/demodulator schematic drawn and  a rough
draft of the components list.  I have several initial questions before I
post the schematic :

1.    In your VBB system do you replace the circuit (output filter &
amplifier) after the 1K/1% resistor on the output of A5 with circuit
shown on your Block Diagram (4/97)?

2.    In trying to download a copy of the MC14066B device, I found that
it has been replaced by MC14016B ( I think that the MC14066B still is
available from suppliers).  It looks like that the only difference is
that the MC14016B has a higher "ON" resistance.

3.    I have a question on the two 100 ohms potentiometers located in
the bridge circuit (Bridge Zero & Zero Test).  According to your notes,
these potentiometers are 1%.  I haven't found any listed in Mouser or
Digi-Key, most are 5 or 10% of listed value.  Maybe you could point me
in the right direction.

Rex Klopfenstein, Jr
Bowling Green, OH



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From: Karl Cunningham 
Subject: Re: VBB Circuitry
Date: Sun, 27 Sep 1998 22:33:52 -0700

Rex --

The problem of stability of multiturn pots is real.  We have done quite a
bit of investigation of  this at work.  Miniature multiturn (usually
20-turn) pots usually one of two mechanisms:  a leadscrew and a slider in
the form of a plastic nut, squashed to reduce backlash (this slider drives
the wiper mechanism); or a worm drive to a wiper.  The same thoughts apply
to both.  Since there is stress on the slider from the screw pushing it
against the friction of the wiper, rapping on the pot after adjusting it
releaves some of this stress and moves the wiper in the process.

If you "unload" the mechanism after adjusting it by reversing the rotation
perhaps 1/32 turn, this instability is much reduced.  You will notice that
the setting changes somewhat when you turn the screw back like this, but
with some practice you can anticipate how much it will be and get it set to
what you want after unloading.

Most miniature multiturn pots have a "cermet" resistive element, which is a
conductive coating on a flat substrate.  The wiper is a spring contact that
makes connection to this conductive coating.  Manufacturers claim
"infinite" resolution -- meaning that the longer you play with it the
closer you will get to the setting you want.  Although harder to find,
another approach is to use wirewound pots instead.  These come in very
similar packages to the cermet units, but are more expensive.  They have
the advantage that after mechanical unloading, the wiper will sit in the
low spot between two wires of the winding and is relatively insensitive to
shock.  It takes a pretty hard jolt to get the wiper to actually jump to
the next wire -- usually impossible.  Their disadvantage is limited
resolution -- on the order of 0.025%.

Single-turn pots are much better for this problem, but the reduced
setability of having only one turn negates much of this advantage for many
uses.  The real answer is to design the rest of the circuit so that the pot
has only enough range to accomplish the needed adjustment and not so much
that instability of the pot is a big factor.  Sometimes a selected resistor
can provide a rough setting and a fine adjustment pot the remainder.

Karl Cunningham
La Mesa, CA.
PSN Station #40
karlc@.......


At 02:11 PM 9/27/98 -0400, you wrote:
>One comment on the selection of potentiometer types (single turn vs
>multiturn).  I didn't come up with this idea myself.  I attended a
>design seminar put on by Analog Devices, Burr-Brown or National (can't
>remember which).  One of the speakers made the following statement:
>"use a single turn potentiometer insures setting stability.  As a test,
>adjust a multiturn potentiometer to desired setting.  At that time tap
>the unit with a pencil and observe the results".  I tried the experiment
>and sure enough, as I tapped the potentiometer the setting changed and
>did not return to original setting.  The speaker blamed the stability
>problems on the more complex mechanism to implement the multiturn
>capability.


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From: S-T Morrissey 
Subject: VBB schematics
Date: Mon, 28 Sep 1998 01:30:03 -0500 (CDT)

Rex,

My prime source for electronics is Newark (www.newark.com).
They have a 1700 page catalogue, take MC and VISA, etc.

The 1% pots are prefered because this includes temperature
and moisture tolerance (moisture is a problem with cermet).
Since the pots are in a bridge, overall change over the 
span will affect the output. Some pots are specified for
resistance tolerance as well as temperature, humidity, 
setability, and repeatability, some of the points that
Karl made. Bourns is a good brand. In the tiltmeters, the 
pots are large wirewound units driven by miniature gearmotors
( by ETI) and controlled by the autozeroing system.
Good bargains in multiturn pots are often found at electronics
surplus stores, often at 10% of retail.

You might want to hold off on finishing your schematic until 
I get the VRDT interface posted. I was going to do it on Friday, 
but the OH / PA quake pre-empted the afternoon. Maybe tomorrow...

The block diagram is just that, and was never intended to 
be a schematic of any usefulness.

The 33microfarad cap at the regulated voltage output might 
as well be polarized, since the voltage is.

Newark lists 3 available packages for the 14066. Its lower
ON resistance also has better temperature behavior.

I don't have internet access here at home, so I will have to
wait to look at the HTML version of the schematic.

Regards,
Sean-Thomas

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From: meredith lamb 
Subject: Afew pictures is all for now...
Date: Mon, 28 Sep 1998 12:17:25 -0600

Hi guys,

Just activated my show and (eventually) tell web site:

http://www.geocities.com/ResearchTriangle/Facility/1739/index.html

One paragraph and 7 jpeg pictures is all there is for now.  The
pictures are all of my "yellowstone" horizontal seismometer.  Derived
the name from the general "model" characteristics of the instrument;
i.e., "dome" (plastic), "layers" (old main frame disks), "pipe" (boom),
"magma chamber" (mass), and of course the general yellow/brown color.
The unit is actually basically patterned after the Shackleford-Gunderson
seismometer on the PSN main web site; only the size is much larger.

The pictures don't show the output/s cables...but the general idea of
construction speaks pretty much for itself.

This is the unit with the linear Hall sensor.  Eventually the circuit
created by Robert Lamb, will show up on the web site; along with
more verbal details.

New at web site confusion with html stuff, so "hang" in there
and more will show up some time.

Meredith Lamb


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From: Karl Cunningham 
Subject: Re: Afew pictures is all for now...
Date: Mon, 28 Sep 1998 14:51:44 -0700

Meredith --

Great photos of your instrument.  Not quite sure what I'm looking at, but
am willing to wait for details.


Karl Cunningham
La Mesa, CA.
PSN station #40
karlc@.......

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From: Greg 
Subject: Re: Afew pictures is all for now...
Date: Mon, 28 Sep 1998 15:36:35 -0700

meredith lamb wrote:
> 
> Hi guys,
> 
> Just activated my show and (eventually) tell web site:
> 
> http://www.geocities.com/ResearchTriangle/Facility/1739/index.html

Very nice pictures. Thanks. I wish I had something new to put on my
site. Maybe in a little while.

> New at web site confusion with html stuff, so "hang" in there
> and more will show up some time.

I just bought a book on HTML myself. This is after I set up a web site
for a local organization. ;)

If anyone gets The Learning Channel you might want to check in on it.
Lately there have been a lot of shows about Earth. I actually learned a
couple of neat things. :) I didn't know about the formation of Iceland
or that Sweden was rising up.

,Greg

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From: "Rex Klopfenstein, Jr." 
Subject: VBB Bridge Potentiometers
Date: Mon, 28 Sep 1998 19:19:08 -0400

Sean

I searched the Newark and Allied catalog and found potentiometers with
overall resistance tolerances from 3% to 20%+, nothing near 1%.  Maybe I
am missing something, when you say 1% do you mean overall resistance
(value across resistance element) or are you talking about something
else like linearity?

Rex Klopfenstein, Jr
Bowling Green, OH



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From: Jim Hannon 
Subject: Re: VBB Bridge Potentiometers
Date: Mon, 28 Sep 1998 19:10:21 -0500

Rex Klopfenstein, Jr. wrote:
> 
> Sean
> 
> I searched the Newark and Allied catalog and found potentiometers with
> overall resistance tolerances from 3% to 20%+, nothing near 1%.  Maybe I
> am missing something, when you say 1% do you mean overall resistance
> (value across resistance element) or are you talking about something
> else like linearity?
> 
> Rex Klopfenstein, Jr
> Bowling Green, OH
> 
Rex,
Sean specified a 1% pot because it in general represents a good quality
part in other respects.  There is no electrical need for the 1% accuracy
of the pot overall resistance. Pick a good quality part of any tolerance
and use it.
-- 
Jim Hannon
http://soli.inav.net/~jmhannon/
42,11.90N 91,39.26W
WB0TXL


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From: S-T Morrissey 
Subject: VBB bridge values
Date: Mon, 28 Sep 1998 22:16:25 -0500 (CDT)

Rex,

You have to bear in mind that the schematics are of circuits that
were originally designed to push the envelope of stability for
electrolytic tiltmeters, where we are aiming for 1 nano-radian
per degree C and 1 micro-radian PER YEAR instability from all
sources. We in fact used 0.25% span tolerance pots for the motor-
driven auto-zeroing, since the bridge resistors at the sensor were
0.01%, 10 ppm/C. The "zero-test" pot was a 5% selected for 1% of span,
since this "zero test" was used to measure the total DC net tilt 
of the installed and un-disturbed instrument over months to years.

Of course, the time span of stability (both mechanical and electronic)
for a VBB seis is usually at most several days (if one wants to 
record earth tides), so such extreme tolerances are not necessary. 
However, the better the overall stability and noise considerations of
the zero control over temp, humidity, setability, etc, the better.
For a VBB instrument, it may be better to omit it all together and 
rely on only mechanical centering if there is a possibility of the 
zero pot contributing noise in the data passband.

In originally presenting these schematics for others to use, I
made no effort to adapt the specifications for a home made VBB 
sensor, since I was recycling them as they were, and didn't want
to get started on considerations and evaluation of more affordable 
adaptations. 

So I have just finished updating the schematics in this direction.
I hope to get them scanned and posted sometime this week.

Regards,
Sean-Thomas

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From: meredith lamb 
Subject: Re: Afew pictures is all for now...
Date: Mon, 28 Sep 1998 21:34:36 -0600



Karl Cunningham wrote:

> Meredith --
>
> Great photos of your instrument.  Not quite sure what I'm looking at, but
> am willing to wait for details.
>
> Karl Cunningham

Karl,

Thanks for the photo compliment.  Actually they are digital
camera results, of the H-P Photo Smart C20 model, and its
associated computer program.  The program does all the usual
stuff, but I didn't have to touch up any.  No tripod for shaky here.

Just got done putting in verbal descriptions under each photo.  I'll
probably change the words endlessly...but its a start-ha.

Thanks,

Meredith Lamb




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From: "Francesco" 
Subject: LARGE QUAKE IN BALKAN REGION
Date: Wed, 30 Sep 1998 00:46:08 +0100

UTC 22.16.06
ML  5.5
LOCATED pre.:  JUGOSLAVIA - BEOGRAD

Some material damnages; non injured at now

I.E.S.N-   PSN ITALY
Francesco Nucera









UTC 22.16.06


ML  5.5


LOCATED pre.:  JUGOSLAVIA -=20
BEOGRAD


 


Some material damnages; non injured =
at=20
now


 


I.E.S.N-   PSN =
ITALY


Francesco =
Nucera


From: Edward Cranswick 
Subject: [Fwd: [Fwd: Pymatuning, Ohio, Earthquake]]
Date: Tue, 29 Sep 1998 22:46:23 -0600

PSN-
    Yesterday afternoon (Monday), Brian Zimmerman came down to visit our
USGS field headquarters here in Greenville, Pennsylvania, to join in the
general hectic frivolity that included TV news helicopters flying in
from Columbus, Ohio, and landing in the field behind our motel so that
they could learn that we were recording no aftershocks. Brian's PSN
station was the closest seismograph to last Friday's Pymatuning
Earthquake and he has been significantly media-ized as a consequence.
Brian also brought his PSN record of the 1998sep28 13:54 Java Earthquake
which is the only eathquake we have recorded so far (see website below).
Then we all, including Leonardo Seeber and John Armbruster from LDEO
(Columbia University) and Ray Buyce, a Geology professor from Mercyhurst
Archeological Institute who is thinking about going PSN, all had dinner
together.
-Edward
The website is:

http://groundmotion.cr.usgs.gov/pym/pym.htm

From: Gregory Bajuk 
Subject: Dataq acquisition module
Date: Wed, 30 Sep 1998 08:43:18 -0700 (PDT)

Dataq Instruments has an Internet special price promotion on a serial port
data acquisition module DI-150.  Features 2 channels, +/- 10 volt input,
12 bit, up to 240 samples per second, and free acquisition, display and
analysis software.  Price $49.95 (1/2 of normal price).  It does not have
all the features of the Data acquisition boards but is a cheap way to get
started in data acquisition with a PC.  Their internet address is:
www.dataq.com

Greg Bajuk


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From: Steve Carniglia 
Subject: Re: Dataq acquisition module
Date: Wed, 30 Sep 1998 08:53:31 -0700 (PDT)

I have a DI190 ...it seems to work great but having some problemes using
the current Seismo software that we all use....

Best Regards
Steve


On Wed, 30 Sep 1998, Gregory Bajuk wrote:

> Dataq Instruments has an Internet special price promotion on a serial port
> data acquisition module DI-150.  Features 2 channels, +/- 10 volt input,
> 12 bit, up to 240 samples per second, and free acquisition, display and
> analysis software.  Price $49.95 (1/2 of normal price).  It does not have
> all the features of the Data acquisition boards but is a cheap way to get
> started in data acquisition with a PC.  Their internet address is:
> www.dataq.com
> 
> Greg Bajuk
> 
> 
> _____________________________________________________________________
> 
> Public Seismic Network Mailing List (PSN-L)
> 
> To leave this list email listserver@............. with the body of the 
> message: leave PSN-L
> 


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From: "Francesco" 
Subject: R: Dataq acquisition module
Date: Wed, 30 Sep 1998 19:16:11 +0100

Which problem have the board using our software (Sdr or Emon or Wq?) ?

Regards
Francesco Nucera









Which problem have the board using =
our software=20
(Sdr or Emon or Wq?) ?


 


Regards


Francesco =
Nucera


From: bzimmerman@............
Subject: Re: [Fwd: [Fwd: Pymatuning, Ohio, Earthquake]]
Date: Wed, 30 Sep 1998 14:45:47 -0500 (EST)

If you ever find yourself close to an earthquake that attracts the 
attention of the USGS, be sure and arrange to have dinner with Edward 
Cranswick.  I learned quite a bit, mostly but not entirely related to 
seismology.  Got some nice pictures of one of their field sites for use in
my classes and good advice on upgrading/improving my system. Nice to see 
my taxes put to good use.  Thanks Ed!
          
Things are slowly getting back to normal here.  Still no aftershocks.

Brian Zimmerman


On Tue, 29 Sep 1998, Edward Cranswick wrote:

> PSN-
>     Yesterday afternoon (Monday), Brian Zimmerman came down to visit our
> USGS field headquarters here in Greenville, Pennsylvania, to join in the
> general hectic frivolity that included TV news helicopters flying in
> from Columbus, Ohio, and landing in the field behind our motel so that
> they could learn that we were recording no aftershocks. Brian's PSN
> station was the closest seismograph to last Friday's Pymatuning
> Earthquake and he has been significantly media-ized as a consequence.
> Brian also brought his PSN record of the 1998sep28 13:54 Java Earthquake
> which is the only eathquake we have recorded so far (see website below).
> Then we all, including Leonardo Seeber and John Armbruster from LDEO
> (Columbia University) and Ray Buyce, a Geology professor from Mercyhurst
> Archeological Institute who is thinking about going PSN, all had dinner
> together.
> -Edward
> 


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