From: Roger Baker Subject: Re: VBB Feedback Date: Wed, 31 Dec 1997 14:43:22 -0600 Friends, There has been a lot of good discussion of force balancing feedback lately, an approach which is pretty much needed for vertical instruments and likely could be used with advantage the Lehman configuration too. Let me add a few comments of my own based on practical experientation. I remain in awe of the experts on such matters. One way to use force feedback, appropriate when the feedback force must be weak, is simply to use a very low pass filter to apply a little trimming force to recenter the DC displacement sensor in its most sensitive zone. This is perhaps best described as drift compensation and sacrifices very low frequency response by constantly nudging the sensor in the direction of its slow average midpoint reading. The signal used is the relatively fast response from the sensor, which may still be noisy due to natural period oscillations. A practical example from my recent experience is a torsion magnetometer which uses a Helmholtz coil to apply a weak field to keep a light beam centered in the detector. The fast oscillations of the magnet/mirror still needed to be damped magnetically with a copper ring. This method is very easy to apply and is intuitive and straightforward and nothing much can go wrong but it doesn't achieve tight dynamic control over the feedback loop. Tight feedback loops and servosystems with response times shorter than the natural period of the system are the best way to go, but tend to require complex analysis to achieve optimum results. Horowitz and Hill deal with the elements of stability criteria in the Art of Electronics. PHDs and mathematicians are in high demand where control system design involving nested feedback loops is concerned. There are some standard tricks that can be used to partly tame control systems and allow maximum gain in the feedback loop without oscillation such as a notch filter to kill gain at the natural period of the system, linking the sensor as closely as possible to the source of force, reducing feedback gain until the system stabilizes, etc. I have found it possible to use a simple adjustable filter in the feedback loop between the voltage output from the sensor and the force coil to stabilize several different magnetic force feedback systems. Assume we have a twelve volt regulated power supply with a virtual ground, a reference point at the voltage midpoint. Our displacement sensor generates a DC voltage which fluctuates above and below this ground reference and we want to feed back magnetic force to push a suspended mass very nearly back towards the point that results in the sensor output being the same as the ground reference voltage, plus six volts in this case. We can feed back the difference betwen the sensor output and the reference voltage straight into a magnetic coil which has one lead tied to this midpoint reference so that the force will try to push the system back to the midpoint. Which is when the system will usually turn into an oscillator, and which we don't want, but it usually means we're on the right track. Instead, I tie the noninverting input of an op amp to the reference voltage. Then I use about a one meg potentiometer and about a one MFD capacitor connected together in parallel between the buffered (meaning we run it through a little op amp voltage follower to beef up its output current a little) sensor output and the inverting input of the op amp. Then I put a second identical pot/cap pair in parallel between the inverting input of the op amp and its output. This is where the feedback resistor of the op amp normally goes. Thats it. The fact is that in many cases some empirical setting of the two pots will OFTEN kill the feedback oscillations and cause the system to lock onto and control the position of the mass in the desired and stable fashion. I like to follow the sensor voltage with a DC amplification stage, where the voltage signal is increased by ten or a hundred times and the output fed into an LED so that one can see the system stabilize by the lack of flickering at the natural oscillation period of the system. This amplified DC output from the sensor is also used as the data stream. The practical effect of such a filter is consistant with all the recent discussion, but I offer it here as a practical way to tame feedback oscillations in systems with natural periods of less than a second. Since magnetic coils tend to have a low resistance, we may need to hang a booster transistor between the output of the op amp and the coil to give lots of current to handle peak demand, but normally the system will probably be nearly balanced and the power demand on the force coil will be low. --Yours, Roger Baker At 09:39 PM 12/30/97 -0600, you wrote: >Karl and co, >Karl, >Our mail passes in the dark, or wherever internet mail goes. I just sent >you: (in case you didn't get it.): > >Karl, >I think I told you already that I have have made a pass at a transfer >function for a 40 second To for your instrument with these >parameters: r = 212 800 V/M (requires 20x gain after your LVDT), Gn = >5.1N/A (for your main coil), M = 0.3kg (much reduced from your 2.27kg, or 5lb, >but needed for the flatness to 10 hz, with damping at 0.69), C= 16 uf, >Rp = 361K ohms, RI = 127K, Rf = 7 ohms, TI = 20 seconds, and To = >4 seconds. This gives a response of 3685 volts/m/sec, flat from 40 >seconds to 10 hz. >Maybe these will be helpful for your new vertical. > >I wasn't sure if I sent all the numbers before. > >Regarding your analysis of the VBB feedback, it is pretty good on most points. >I tend to rely on the mathematical model as strongly as the engineering >intuition to understand what is going on. > >As I have mentioned before, the feedback is still a summation of currents >into the force coil, NOT voltages. So inserting a voltage amplifier between >the feedback elements and the coil will not produce a VBB response. Maybe >a "Norton" current amp might work, but unless the differential and integral >currents can both be controlled by their circuit elements, their effect >will be nil. In the transfer function, the flat response occurs when the >differential feedback dominates at less than To with the same magnitude that >the integral feedback dominates below To. In fact, this creates an oscillator >right AT To, so the proportional current through Rp is needed to damp the >system, which will actually oscillate if Rp is open. > >Regarding the relative DC or static mass movement (as compared with >the dynamic movement, which is much less): it is controlled by both the >proportional and integral currents, and depends on the sensitivity >of the mechanical suspension restoring force, which ideally would be >zero and the period infinite. However, in a stable instrument it is handy >to have the mass come to an equilibrium position, which is even more useful >since the restoring force also aids in dealing with significant >temperature effects. So the mechanical restoring force is finite but small, >meaning that the feedback will allow some DC movement of the mass. > >This amount is easily determined by measuring the displacement output >with the feedback on as well as off. On the prototype here, the ratio >is about 10 to 1. This also means that if I determine the sensitivity of >my 5-turn calibration coil (using the VRDT with the feedback off) to be >25 nanometers / microamp (it is actually 26.4), the mass only moves >2.5 nm /uamp. I need a step current of 30ua to produce a voltage of about >100 mv (peak pulse voltage) at the VBB output, which is equilavent to an >actual step movement of the mass of 12 nanometers. Naturally, if the >feedback perfectly controlled the static position of the mass, a step >calibration would not work except for the transient time of Td. > >Regarding the sensitivity of the displacement transducer: with a sensitivity >of say 50mv/micron and a 10x amp, it is 0.5 Volt/micron, or 500V/mm, or >500 000 Volts/meter. Sounds like a lot, until you realize that we are >trying to measure 10**-10 meter, or 0.1 nanometer, which would have a >voltage of only 5 microvolts, which is near the low noise limit of even >high quality amplifiers. With my prototype here, the VBB output is about >3200 V/M/sec, but the 6-second microseisms come in at only 1 to 5 millivolts. >And it took the M 7.7 in Tibet to clip the 12-bit digitizer here at 200mv. >My maximum output is 7 volts, so I need the 16-bit ADC; actually, if my >noise floor IS 5 microvolts, I have a dynamic range of 122.9db, which would >take a 20-bit ADC to resolve. And conversely, a peak of 7 volts is a peak >velocity of 2.18mm/second, or a pretty good shake (you can feel 10 microns/ >second). > >In terms of earthquake magnitude, if we have a Mb3.0 at 110km (1 deg), and >Mblg = 3.75 + 0.9*log[DELTA](degrees) +log[A](microns), the amplitude is >0.178 microns (at 1 hz). A magnitude 5 at the same distance would have an >amplitude of 17.8 microns. > >And finally, regarding the size of the mass: larger is better if you have >a powerful feedback coil, like the 90N/A in the S5000 with the ll kg >mass, but the commercial VBB sensors have masses from 0.3 to 0.6 kg, with >force coils around 20N/A for more high frequency output. If I model your >sensor with the 2.7kg mass, the response is a rounded bump, much like a >narrowband LP seis; the feedback currents simply cannot control it. >The response is nicely broad and flat with the 0.3kg mass. > >I hope that I have answered your questions. > >Regards, >Sean-Thomas > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Marnie Gannon Subject: Yikes..Mammoth again Date: Wed, 31 Dec 1997 13:55:09 -0700 Update time = Wed Dec 31 12:47:29 PST 1997 Here are the 30 most recent earthquakes and all big earthquakes on this map... MAG DATE LOCAL-TIME LAT LON DEPTH LOCATION y/m/d h:m:s deg deg km 1.7 97/12/31 12:44:36 37.64N 118.87W 7.2 6 mi E of MAMMOTH LAKES 1.4 97/12/31 12:43:36 37.63N 118.84W 7.5 7 mi E of MAMMOTH LAKES 1.9 97/12/31 12:43:03 37.63N 118.86W 7.7 6 mi ESE of MAMMOTH LAKES 3.2 97/12/31 12:41:47 37.63N 118.86W 7.0 6 mi E of MAMMOTH LAKES 1.4 97/12/31 12:41:28 37.63N 118.83W 8.5 8 mi ESE of MAMMOTH LAKES 3.7 97/12/31 12:39:52 37.62N 118.86W 5.2 6 mi ESE of MAMMOTH LAKES 4.7 97/12/31 12:36:47 37.63N 118.87W 6.9 6 mi ESE of MAMMOTH LAKES 1.8 97/12/31 12:36:31 37.63N 118.87W 6.3 6 mi E of MAMMOTH LAKES _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: VBB Feedback Date: Wed, 31 Dec 1997 13:29:38 -0800 Sean-Thomas: To increase the effective feedback coil sensitivity, consider a current-in/current-out amplifier. I haven't looked into the magnitude of noise and drift introduced from the op-amp, but the following circuit may work: R1 +---\/\/\/\-----+ | | | |\ | | | \ | Current from VBB Feedback Ckt ---+---|- \ | R2 | >-----+---\/\/\/\---- To Feedback coil +---|+ / | | / | |/ -+- \ / V The current gain is R1/(R2+Rf), where Rf is the feedback coil's dc resistance. R2 should be substantially larger than the inductive reactance of the feedback coil at the highest frequency of significant energy from the VBB feedback. Otherwise, the drive to the coil is not so purely a current and, as you say, the result won't be a true VBB response. For speaker coils and the like, this shouldn't present a problem. Also to be considered is the emf generated across the coil when moving in the magnetic field, which will disrupt the true current feedback. So long as this emf is low compared to the voltage across (R2+Rf) at the same point in time, this shouldn't be a problem either. Your sensitivity/dynamic range numbers sound good. I've done a spreadsheet with your equations so I can play with the numbers and look at the results. I'll see if I can come up with a solution with viable component values for my vertical. Thanks a lot for your help. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: TESMECO Subject: great post Date: Wed, 31 Dec 1997 17:11:19 EST we should send more info like this on this list thanks greatly appreciated TIM SLU SEEYA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Bob Fryer Subject: Re: great post Date: Wed, 31 Dec 1997 14:45:02 -0800 Uhhh, Tim, What post were you referring to? Bob F >we should send more info like this on this list > > thanks greatly appreciated TIM SLU > > >SEEYA > >_____________________________________________________________________ > ----- earthquake WARNING research ----- --- animals, people, scientific evidence --- --- http://www.teleport.com/~bfryer --- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: TESMECO Subject: Re: great post Date: Wed, 31 Dec 1997 18:04:32 EST the mammoth info great visual aid it was all compiled so ididnt have to go get thats all tim slu seeya _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: fmurray@......... (frank murray) Subject: Re: Notice the 3 SAF M3's... Date: Wed, 31 Dec 1997 23:12:59 GMT On Wed, 31 Dec 97 19:40:20 +0000, frank condon wrote: >Bombay Beach lives for another day! After getting out the maps and = locating the >faults in relation to the most recent activity, I believe your statement= is=20 >correct. Isn't it kind of close to the cinder cones at Obsidian Butte? = Could=20 >we be looking at the start of another geothermally active spot like = Mammoth=20 >Lakes and Little Lake? coincidentally, or perhaps not, when the niland quake at 14:32:03 occurred, the sequence at mammoth slowed to a thirteen minute gap between quakes...no other gap at mammoth had exceeded about three minutes since the M4.8...nor had any other niland quakes occurred during the time since that M4.8...after that thirteen minute gap the quakes at mammoth returned to a frequency of about one per minute...speculation??... frank fmurray@......... for my electronic college proposal see: http://home.att.net/~fjtmurray/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: VBB Feedback Date: Wed, 31 Dec 1997 17:57:33 -0600 (CST) Karl, Of course the only thing to do is to try it. My feeling is that if the designers of the commercial instruments don't do it, it probably won't work. I believe that the reason is, as I have mentioned before, that the feedback currents MUST be controlled by the three feedback elements Rp, C, and RI sumultaneously controlling the current through the feedback coil. Anything between them and the coil modifies their behavior, and the transfer function, which is actually an expression of accelerations, doesn't work. I know that your present coil will work as is; if not, speakers are cheap. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: STM-8 photos Date: Wed, 31 Dec 1997 18:05:16 -0600 (CST) To those interested in the broadband leaf spring vertical seismometer: I have spent my holiday getting up to speed with a web page at //www.eas.slu.edu/People/Staff/STMorrissey. It is a bit primitive so far, and the paper on the homemade seis is in limbo until I can find a converter from RTF to .html, but I have posted a few photos of the leaf-spring prototype. Your comments and suggestions are appreciated. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Caruso Subject: digression? Date: Wed, 31 Dec 1997 20:19:00 -0500 (EST) I was wondering if anyone has an update on the meteor impact in greenland? STEPHEN CARUSO CET KB8UGH "Coincidence is a shortsighted mental delusion" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Yikes..Mammoth again Date: Wed, 31 Dec 1997 17:45:42 -0800 (PST) So Mammoth Mountain takes a vacation for the holidays. But, returns to celebrate the New Year with a bang! Frank Condon mail to:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" >Update time = Wed Dec 31 12:47:29 PST 1997 >Here are the 30 most recent earthquakes and all big earthquakes on this >map... > >MAG DATE LOCAL-TIME LAT LON DEPTH LOCATION > y/m/d h:m:s deg deg km > >1.7 97/12/31 12:44:36 37.64N 118.87W 7.2 6 mi E of MAMMOTH LAKES >1.4 97/12/31 12:43:36 37.63N 118.84W 7.5 7 mi E of MAMMOTH LAKES >1.9 97/12/31 12:43:03 37.63N 118.86W 7.7 6 mi ESE of MAMMOTH LAKES >3.2 97/12/31 12:41:47 37.63N 118.86W 7.0 6 mi E of MAMMOTH LAKES >1.4 97/12/31 12:41:28 37.63N 118.83W 8.5 8 mi ESE of MAMMOTH LAKES >3.7 97/12/31 12:39:52 37.62N 118.86W 5.2 6 mi ESE of MAMMOTH LAKES >4.7 97/12/31 12:36:47 37.63N 118.87W 6.9 6 mi ESE of MAMMOTH LAKES >1.8 97/12/31 12:36:31 37.63N 118.87W 6.3 6 mi E of 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) From: dean sevold Subject: Fwd: Re: Meteorite fall Date: Wed, 31 Dec 97 18:58:00 PST Date: Tue, 30 Dec 97 11:41:48 PST From: Klaus Georg Hansen To: dean sevold Subject: Re: Meteorite fall Dear Dean No news - Nothing will happen before January 2nd 1998. I'll keep you informed. Happy New Year. Klaus This is all the news from greenland, but am expecting more shortly Deasn _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ken Navarre Subject: Re: LEAF-SPRING Date: Wed, 31 Dec 1997 19:22:32 -0800 (PST) On Mon, 29 Dec 1997, S-T Morrissey wrote: > Ken and Jim, > The word to the wise about out-of-control leaf springs IS good advice. > One of mine got loose and flung a good collection of small stainless > hardware into the next room, causing my dogs to panic and hide in the > bedroom. Yeah, that sounds like what I observed... :( [snip] > Regarding damping with magnets, it was used on all the early seismometers > that has optical levers. It uses the principle of eddy currents, where > a thick copper vane moves in a very strong magnetic field. The movement > causes currents in the copper, whose induced field counters the motion. > I would consider using rare-earth magnets with an old real copper penny. I've installed the magnet from a large speaker in the vertical plane under the end of the boom. For damping I've hung a piece of copper salvaged from a high voltage electrical bus its 4" x 4" x 1/4" and weighs a couple pounds. A 2 mm seperation between the magnet and copper damps the swing in 2 cycles. A small ceramic magnet is attached to the top of the boom and faces the sensing coil. The sensing coil is mounted with aluminium angle and is easily adjusted to minimal spacing. This arrangement is certainly no improvement to Sean's design but it gave me a vertical to get on-line while I get up to speed with the electronics. KEn _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: New Event Date: Wed, 31 Dec 1997 12:16:39 -0800 Hi all Has anyone picked up a fairly large distant event @ about 06:10:51 UTC 01/01/98? It's possible I'm picking up wind vibrations. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: New Event Date: Thu, 1 Jan 1998 00:57:10 -0800 (PST) I see this one is listed for the proper time. 98/01/01 06:11:16 24.00N 141.99E 33.0 6.7Mb B VOLCANO ISLANDS REGION Must not be the wind. Frank Condon >Hi all > Has anyone picked up a fairly large distant event @ about 06:10:51 >UTC 01/01/98? It's possible I'm picking up wind vibrations. > Barry > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Seisguy Subject: Fwd: Earthquakes Fewer, Deadlier in '97 Date: Thu, 1 Jan 1998 07:50:58 EST 
Earthquakes Fewer, Deadlier in '97


.c The Associated
Press


 WASHINGTON (AP) - The U.S. Geological Survey reports there were fewer
earthquakes than usual in 1997, but they killed more people.

The agency said Wednesday it recorded 17 major tremors during the year,
meaning those with a magnitude of 7.0 or more and thus capable of widespread,
heavy damage.

The annual average is 20 major quakes. There were 21 in 1996.

Meanwhile, the agency said it recorded the first significant quake of 1998 at
1:11 a.m. EST today in a string of unoccupied volcanic islands off Japan.

It said the epicenter of the quake, which recorded a preliminary magnitude of
6.5, was about 65 miles southwest of Iwo Jima and was unlikely to have been
felt because of the isolated location in the Pacific Ocean. There were no
reports of damage.

Despite the decline in temblors, the 1997 death toll was at least 2,913, up
from 449 in 1996, according to figures compiled by the Survey's National
Earthquake Information Center in Golden, Colo.

The year's deadliest earthquake struck northern Iran on May 10 with a
magnitude of 7.1. It caused at least 1,567 deaths, 2,300 injuries and left
50,000 homeless.

In the United States the year's strongest quake had a magnitude of 4.9 and
struck the state of Washington in June, causing slight damage at Bremerton and
Poulsbo.

Other significant earthquakes for the year occurred near the East coast of
Kamchatka, Russia, and near the coast of central Chile.

The strongest earthquake in the world in 1997 struck Xizang Province, Tibet,
about 520 miles north-northeast of Katmandu, Nepal, on Nov. 8.

AP-NY-01-01-98 0701EST


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


 

To edit your profile, go to keyword NewsProfiles.
For all of today's news, go to keyword News.
From: Robert L Barns <75612.2635@..............> Subject: Rockland filter Date: Thu, 1 Jan 1998 09:16:44 -0500 Hi gang, Here's something you might look for at a hamfest or on used equipment lists. I find it a very useful accessory to my Lehman. I got it from Bi= ll Scolnic. He found it at a hamfest. He uses a Kron-Hite filter which I think is quite similar. I'm guessing that $100 or so might get one or th= e other at a hamfest. It is a Rockland Systems Corp. adjustable filter, Model 1022F. It is i= n a 19" rack mount case 5 1/2" high and is not very heavy. It contains 2 identical sections and the data below are for each section. I don't have the manual so the data are my measurements. A switch selects either low or high pass. There are 3 decimal dials (X.XX) and a 1X, 10X, 100X and 1000X range switch. This allows setting the knee frequency from 0.01Hz to 9,990 Hz! A switch selects either 0 or 20db gai= n. With the knee frequency set at either 0.08Hz or 200Hz, I found that the slope above the knee of the low pass filter is 24db/octave with no vis. ripple. Who could ask for anything more? The output is from DC with an offset in the output of about 5 mV and I saw no clipping with output voltages up to 9V. The input impedence is 1= megohm. There is a switch for each section labelled BW-AC. Can anyone explain this switch? I don't know the vintage but found it interesting that the active components look to be all transistors-no op-amps. When I got it, the lef= t section worked fine but the right section was a mess. Each section consists of 5 or 6 small (3X4" about) plug-in cards. I started to troubleshoot the right section by swapping these cards from section to section but I discovered that one of the cards in the right section was plugged-in BACKWARDS. Putting this in the right way fixed it. Since I have only one seismometer, I'm using it set at 0.08Hz with the= two sections in series so that the slope above the knee is 48db/octave. = With my old home-made 6-pole 0.08Hz filter, I could always see some of th= e noise peak at 0.016Hz. With 48 db/octave, this peak is not seen. A filter which is so easily adjusted opens the door to various experiments. Happy hunting & Happy New Year! Bob Barns = = _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Bob Thomasson <102073.3346@..............> Subject: Re: Notice the 3 SAF M3's... Date: Thu, 1 Jan 1998 12:58:56 -0500 <> The same day of the Sylmar, CA quake in 1970 a new fumarole opened up at Hot Creek near Mammoth. The USGS claimed it was pure coincidence, but it= does make you wonder, doesn't it? Regards, Bob _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Re: STM-8 photos Date: Thu, 01 Jan 1998 11:48:22 >I have spent my holiday getting up to speed with a web page >at //www.eas.slu.edu/People/Staff/STMorrissey. Just tried it and it says no such page Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: SEAN-THOMAS'S WEB PAGE Date: Thu, 1 Jan 1998 14:39:57 EST TO: SEAN-THOMAS I think I may have copied your web page address incorrectly. Tried to access it but was informed repeatedly that AOL could no find URL. Can you give it again. I copied: http://www.eas.slu.edu/People/Staff/STMorrissey Jim Allen Cerritos, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: STM-8 photos Date: Thu, 01 Jan 1998 13:54:19 -0600 Norman Davis WB6SHI wrote: > > >I have spent my holiday getting up to speed with a web page > >at //www.eas.slu.edu/People/Staff/STMorrissey. > > Just tried it and it says no such page > > Norman Davis WB6SHI > Email normd@............. > Shingle Springs, Ca, USA it ain't local... > I had to fiddle around a little to find it. TRY http://www.eas.slu.edu/People/STMorrissey/index.html -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Charlie Rond Subject: Re: SEAN-THOMAS'S WEB PAGE Date: Thu, 01 Jan 1998 15:16:40 -0600 Jim, >TO: SEAN-THOMAS > >I think I may have copied your web page address incorrectly. Tried to access >it but was informed repeatedly that AOL could no find URL. Can you give it >again. I copied: http://www.eas.slu.edu/People/Staff/STMorrissey >Jim Allen >Cerritos, California My apologies to Sean-Thomas for speaking for him, but I've located his page. http://www.eas.slu.edu/People/STMorrissey/index.html Thought I might step in for him while he's watching the football games :-) Happy New Year! Charlie Rond -\/\--Public Seismic Network-Memphis rond@................ (901) 360-0302 [ free BBS ] http://gandlf.ceri.memphis.edu/~rond http://gandlf.ceri.memphis.edu/~rond/psn _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Current Status of Mammoth Date: Thu, 1 Jan 1998 13:37:29 -0800 (PST) Hi All: Finally they updated the Web page that is dedicated to telling the public about the CURRENT CONDITION at Mammoth Lakes: --------------------------------------------------------------------------- Caldera activity: An energetic swarm of earthquakes in the south moat of the caldera (centered in the vicinity of the airport, 6 to 7 miles ESE of Mammoth Lakes) began with a M=4.8 earthquake at 12:37 PM on December 31. This swarm has included nearly 1,000 events through 9:45 AM on the 1st as detected and located by the realtime computer system. Some 48 of these earthquakes have magnitudes of M=2.5 or greater and 13 have magnitudes of M=3.0 or greater. Swarm earthquakes with magnitudes of M=3.5 or greater include M=3.6 and M=3.7 events at 12:40 PM, a pair of M=3.5 events at 4:55 PM and 9:32 PM all on the 31st, and a M=3.8 event at 4:19 AM on the 1st. The latter was part of a second swarm centered 2 miles ESE of Mammoth Lakes that began at 4:15 AM on the 1st. The pattern of ground deformation has not shown any marked changes associated with this swarm activity. The resurgent dome continues to inflate at about the same rate as observed in late-October and early November. The condition remains GREEN. ----------------------------------------------------------------- A strong upsurge in activity around the full Moon... Hmm! Is there a corelation between volcanic activity and the phases of the Moon? Could it be the ocean tides have an effect, too! Frank Condon mail to:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: Re: SEAN-THOMAS'S WEB PAGE Date: Thu, 1 Jan 1998 17:58:40 EST TO: CHARLIE ROND Thanks Charlie. Sean-Thomas's web page is very nice. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Current Status of Mammoth Date: Fri, 02 Jan 1998 12:03:26 +1200 >A strong upsurge in activity around the full Moon... Hmm! Is there a >corelation between volcanic activity and the phases of the Moon? Could it be >the ocean tides have an effect, too! > the 30 dec new moon not full moon but but sun and moon wouls be pulling in same direction Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: EMON CONFIGURATION Date: Thu, 1 Jan 1998 19:51:13 EST TO: BOB HAMMOND AND ALL LIST MEMBERS Thanks to the assistance of Bob Hammon I now have EMON up and running. I have several questions: 1. Is there a way to change the resolution? My screen shows a signal pattern with the dots Not Connected. I have changed the verticle compression of displayed signal to 20 and the horizonal to 15 which seemed to help somewhat. 2. Is there a way to add color to the screen, even IBM Blue? When the program saves the traces and I view it in Winquake the trace is good. I am using EMON configured for the CIO-DAS08/Jr 12-bit A/D. Any suggestions would be appreciated. Jim Allen Cerritos, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: 3d map visulation Date: Thu, 01 Jan 1998 18:59:05 -0600 A friend just sent me this link. Very interesting freeware for visulation of 3d map data and some links to online 3d map data. Haven't tried it out yet. http://www.monumental.com/rshorne/3dem.html -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: web page Date: Thu, 1 Jan 1998 19:06:46 -0600 (CST) Hi Meredith, Norman,Jim, Larry, Charlie. Mike, et al. I appreciate your comments on my effort at a web page. Sorry about making it hard to find; when I start netscape on our server, it defaults to the department page, and I just click on the People, Staff. etc to get around. I guess other access needs the final path links. I appreciate Charlie's effort at solving the problem. I wonder what an aol access would find at just //www.eas.slu.edu ??. So I spent the day replacing the protorype leaf spring broadband with the "new, improved" BETA instrument on my pier in the basement. Of course its' too soon to evaluate it, but it seems to be continuing the 6-second microseism noise (from the storm off the east coast) and the local windy-day noise that the prototype was producing, and the calibration pulse still looks like that of a 90 second instrument. I will try to get sharper, clearer photos of it onto the web page. I've also been advised that html doesn't DO equations, so I'll scan the figures, graphics, and schematics for the paper and post them. Maybe tomorrow. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Marnie Gannon Subject: NPR- Volcano Date: Fri, 02 Jan 1998 11:02:47 -0700 Hey Guys.. taking a look around NPR archives..last weeks' Science Friday has an hour long report on volcanoes in realaudio..If you don't listen today then you will need to go to the archives..Go Here: http://www.npr.org/programs/totn/archives/scifricurrent.html Discussion with David Hill at Long Valley, Steve Malone of UW re Rainier and other Cascadia Volcanoes, and Jill Norton, chief scientist at Montserrat..also a call in section which touches on other US volcanoes.. Marnie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Seisguy Subject: Fwd: Mexico Volcano Spews Ash, Lava Date: Fri, 2 Jan 1998 13:20:57 EST Happy New Year Popo! Now take some Tylenol and sleep it off.....;-) Mike 
Mexico Volcano Spews Ash, Lava


.c The Associated
Press


 MEXICO CITY (AP) - Hot ash rained on the outskirts of Mexico City when snow-
capped Popocatepetl volcano erupted for the second time in two weeks, spewing
glowing rock and smoke into the air.

The 18,000-foot volcano settled down 90 seconds after erupting Thursday
evening, and there were no reports of injuries or damage, officials told the
government news service Notimex.

Ash fell on nearby communities, and Notimex said the roar of the eruption
shook windows and doors of houses. Authorities said the eruption was
accompanied by a magnitude-3.5 earthquake.

The volcano 45 miles southeast of Mexico City last erupted on Dec. 24.

Government Ministry official Ricardo Garcia Villalobos was quoted by Notimex
as saying the smoke from the most recent blast rose two miles into the sky.

He said the blast was smaller than the June 30 eruption that shot a
40,000-foot plume of ash into the air, the biggest exhalation since 1925. It
coated Mexico City in ash, causing massive traffic jams.

Popocatepetl - which means ``smoking mountain'' in the language of the ancient
Aztecs - had been quiet for 70 years until periodic eruptions began in 1994.

AP-NY-01-02-98 0435EST


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


 

To edit your profile, go to keyword NewsProfiles.
For all of today's news, go to keyword News.
From: "David A. Nelson" Subject: Mt Ruapehu active Date: Sat, 03 Jan 1998 10:03:57 +1200 hi all, trust everyone has recovered from the festivities and there are not tooo many sore heads. :) just to let u know yesterday 02 Jan 98 New Zealand Mt ruapehu did 2 significant ash eruptions covering the mountain slopes with the fallout. These are the first for the last ~3 months 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 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: SFBA PSN records for Mike Antolik Date: Fri, 02 Jan 1998 14:53:01 -0700 PSN members in the San Francisco Bay Area- 3-dimensional, finite-difference models of seismic wave propagation and site response in the San Francisco Bay Area created by members of the Seismic Station at UCB can be seen: http://www.seismo.berkeley.edu/seismo/events_of_interest/3dmod/3dmod.html -Edward -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: shammon1@............. Subject: Re: SFBA PSN records for Mike Antolik Date: Fri, 02 Jan 1998 18:45:07 -0800 Hi Ed, (and group) Great meeting-- I've been kind of slow in getting my act together because of the holidays... I have the film from the meeting at the local photo drop and as sonn I get it back and the scanner running again I'll post them to the San Jose PSN web site. I'll make an announcement on the PSN-List as soon as it done. QUESTION-- help me out here. When was the Alum Rock Quake? I lost my notes and I'm looking for the data you asked about. Regards, Steve Hammond PSN San Jose Edward Cranswick wrote: > > PSN members in the San Francisco Bay Area- > 3-dimensional, finite-difference models of seismic wave propagation and > site response in the San Francisco Bay Area created by members of the > Seismic Station at UCB can be seen: > > http://www.seismo.berkeley.edu/seismo/events_of_interest/3dmod/3dmod.html> > -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) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Seisguy Subject: Re: SFBA PSN records for Mike Antolik Date: Fri, 2 Jan 1998 21:26:39 EST In a message dated 98-01-02 20:52:26 EST, you write: > QUESTION-- help me out here. When was the Alum Rock Quake? I lost my > notes and I'm looking for the data you asked about. > Steve, that M4.7 quake was May 21, 1996 @ 1:50pm. Regards, Mike O'Bleness Northridge, Ca _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: EMON CONFIGURATION Date: Fri, 02 Jan 1998 06:23:54 -0800 Hi Jim I asked Ted the same question several years ago. Plotting is done with points rather than lines to speed up the program sample rate. PSET is quicker than LINE. I don't know about the color. I have been viewing green on black for a while. I guess I got use to it. Barry RADIOTEL wrote: > > TO: BOB HAMMOND AND ALL LIST MEMBERS > > Thanks to the assistance of Bob Hammon I now have EMON up and running. I have > several questions: > 1. Is there a way to change the resolution? My screen shows a signal pattern > with > the dots Not Connected. I have changed the verticle compression of > displayed > signal to 20 and the horizonal to 15 which seemed to help somewhat. > 2. Is there a way to add color to the screen, even IBM Blue? > When the program saves the traces and I view it in Winquake the trace is good. > I am using EMON configured for the CIO-DAS08/Jr 12-bit A/D. > > Any suggestions would be appreciated. > Jim Allen > Cerritos, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: STM-8 documents Date: Fri, 2 Jan 1998 21:32:03 -0600 (CST) To those interested in the broadband leaf-spring vertical seis: I managed to get some of the drawings and schematics onto my web page at //www.eas.slu.edu/People/STMorrissey/index.html. It is still a bit disorganized, and it took me a while to figure out how to get readable documents without having giant files, but it is a start. ........ And Saturday is a good day to start gathering parts ...... Your comments and suggestions are, of course, welcome. The drawings are in .gif format. Someone advised me that I could put them out in .RTF format if someone's browser had the "plug in" too read it. Any comments? Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: Re: EMON CONFIGURATION Date: Fri, 2 Jan 1998 22:48:21 EST TO: BARRY LOTZ Thanks for your assistance re. EMON. Jim Allen Cerritos, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: peaches@............ (Donna Whitaker) Subject: Kilauea Volcano Date: Fri, 2 Jan 1998 22:30:16 -1000 (HST) Hi all. Today, Jan 3 marks the 15th year of the Pu'u O'o eruption at Kilauea volcano on the Big Island of Hawaii. Here is the Hawaii Volcano Observatory (HVO) update URL which has their latest info and some nice picts. Enjoy and Aloha. http://hvo.wr.usgs.gov/geology/update2.html Tony Potenzo PSN Kona Station _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Doug Crice Subject: Pictures and drawings on the web Date: Sat, 03 Jan 1998 10:21:20 -0800 As a general rule, I think illustrations should be in either .GIF or ..JPG format, since virtually all browsers support these two standards for viewing. ..GIF is preferred for drawings, and will generally be most efficient for them. .GIF has only 256 colors, which keeps the size down. ..JPG (or jpeg) is preferred for photographs. It's a standard file compressing method which produces small files with lots of colors. If you want to get elegant, use progressive JIF and JPG, the kind of figures that appear full size then gradually get better as more of the file downloads. That way, the reader can either be entertained while he's waiting or go on if he's not interested. There is a pretty good graphics/photo editing program Lviewpro which can create these formats from others, available for download from http://lview.com/ Doug Crice _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: Pictures and drawings on the web Date: Sat, 03 Jan 1998 11:57:23 -0700 (MST) On Sat, 3 Jan 1998, Doug Crice wrote: > As a general rule, I think illustrations should be in either .GIF or > .JPG format, since virtually all browsers support these two standards > for viewing. I think .tiff files are supported for Netscape on all platforms now as well, though I don't use them very often. > .JPG (or jpeg) is preferred for photographs. It's a standard file > compressing method which produces small files with lots of colors. > There is a pretty good graphics/photo editing program Lviewpro which can > create these formats from others, available for download from > http://lview.com/ This is true indeed. But I haven't yet found a program better than Adobe Photoshop for every graphics task. JPEGs have an option which you can control which is the compression of the graphic, which is something you can play with when saving a JPEG in Photoshop. But the accuracy of the image decreases with the amount of compression so that what you are seeing as you compress it more and more is only an approximation of the original. However, for most people browsing in 256 colors or even thousands of colors this difference is almost entirely undetectable. But then again, nothing beats the crispness of a less compressed, well-scanned photo while viewing in 32-bit true RGB. My best result of this can be seen in a photo of Superstition Mountain near Mesa I have posted to my web site. The URL is http:/www.public.asu.edu/~hernlund/ Sure, Photoshop can be expensive if you buy it yourself, but it is worth every penny. This software has also been invaluable to scientific research based on digital images (Hubble, etc.) due to all the manipulation tools and macros/filters it supports. ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: coil winding,etc Date: Sat, 3 Jan 1998 13:02:07 -0600 (CST) Jim, Before you wind your coil with 1/2 pound of # 34 wire, here are some considerations. That amount of #34 has a resistance of 1084 ohms at room temperature, which is way too much if you intend to use it for a feedback coil. I would suggest using much larger wire, not only to reduce the resistance, but to create a stronger electromagnet for use as a feedback or force coil. (This should not be confused with the voltage produced by moving a coil in a magnetic field, in which the more the turns, the greater the voltage.) For example, if you use #30, it has 170 ohms / 1/2 lb; however, it has a cross section of 0.000079 sq.", whereas the #34 is 0.000031. So the #30 has about 2.5 times the area, meaning that in the same coil form it will give 1/2.5 (0.4) times the number of turns. But the resistance of #30 is 1/6.4 (0.16) x that of #34. The strength of an electromagnet is determined by the Ampere-turns (# turns x current); so even if you get only 0.4 of the turns, with 0.16 of the resistance, you have 6.4 times the current for the same voltage, or 0.4/0.16 = 2.5 times the Ampere-turns or field strength. Going even further, #24 wire has 1/10 the cross section of #34, but only 10.5 ohm/0.5 lb, or 1/100th that of #34. so the induced field will be 10x stronger. This is why stereo speakers have such low resistances. Regarding the natural period of your seismometer; I am confused by your mention of 100 and 600 seconds; I guess that these are the length of the decay time of the free oscillations, and not the natural period. The natural period will range from less than 1 to more than 20 seconds for most mechanical systems. It is determined by measuring the time of, say, 10 oscilations, with a stopwatch and dividing. If the system has minimal frictional or air damping, it should oscillate a few mm for at least a minute or two. If you have the lower end of the leaf spring clamped to the base, it will force the natural period to be very short. Both ends of the spring must be able to flex, ie. follow the curvature of the whole spring. When the ends are about 5.5 to 6" apart, it starts to exhibit "zero length" behavior, where the restoring force is constant for small changes in length. At this point very long periods, even instability, are realized. This is achieved with coil springs by twisting the wire as it is coiled, so the spring requires a large initial force just to open it, which is why this type of spring is used for vertical seismometers. I am working on a writeup of the details of the leaf-spring installation; I will send you a draft later today. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: The Latest Swarm in Mammoth Date: Sat, 3 Jan 1998 11:23:56 -0800 (PST) Hello All: Here is an updated CURRENT CONDITION report on Mammoth Lakes from the official USGS Long Valley Caldera Web Site: -------------------------------------------------------------------- Caldera activity: The gradual decay in the level of earthquake swarm associated with the M=4.8 earthquake of December 31 was interrupted with a slight increase in activity in the early hours of Jan. 3. This activity, which continues to be concentrated in the area between the airport and fish hatchery (5 to 7 miles E of Mammoth Lakes), included three earthquakes of magnitude M=3.0 or greater: a pair of M=3.0 events at 2:19 AM and 2:57 AM respectvely, and a M=3.2 event at 3:38 AM. The realtime computer system detected and located some 250 events over the past 24 hours, nine of which had magnitudes of M=2.5 or greater (including the three M>3 events mentioned above). The resurgent dome continues to inflate at about the same rate as observed in late-October and early November. -------------------------------------------------------------- Frank Condon mail to:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: STM-8 documents Date: Sat, 03 Jan 1998 00:36:26 -0800 Sean Thomas I appreciate your effort. GIF is was ok for me. I used paintshop pro and had good resolution. I only had problems with the horizontal scale on the graphs (clipped) but I was more interested in the schematics. I have been looking for awhile for documentation that would increase the effective period of a sensor electronically. I am in the process of trying to take your feedback ideas and incorporating it with the vertically hung horizontal sensor (Like the SG suspension- less problem with drift than my long period garden gate Lehman). I'll let you know how it goes. I am currently trying to center the Radio Shack coil in the magnet with only a 8" sensor arm. Thanks again for your efforts. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Tobin Fricke" Subject: Re: Pictures and drawings on the web Date: Sat, 3 Jan 1998 11:35:12 -0800 > I think .tiff files are supported for Netscape on all platforms now as >well, though I don't use them very often. I'd stay away from TIFF files on the web. If a web browser supports images at all, it will support GIF, and most likely JPG. Version 4 browsers have some support for PNG, an excellent format. Photographs should use JPG Drawings and diagrams should use GIF Tobin _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Your Name Subject: Solder Geophone Terminals??? Date: Sat, 03 Jan 1998 12:11:11 -0800 Can you solder directly to the two little terminals on top of a GS-11D geophone without messing up the sensor??? Thanks! Roger - KD6LQE _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: Solder Geophone Terminals??? Date: Sat, 3 Jan 1998 14:53:22 -0600 (CST) Roger, Yes you can solder to the terminals, but with a relatively small solder pencil. The current in the tip of a solder gun may demagnetize the magnet of the little geophone. The damping resistor is usually soldered across the terminals. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Solder Geophone Terminals??? Date: Sun, 04 Jan 1998 10:02:38 +1200 At 12:11 PM 1/3/98 -0800, you wrote: >Can you solder directly to the two little terminals on top >of a GS-11D geophone without messing up the sensor??? >Thanks! Roger - KD6LQE Yes no trouble at all, al of the ones I have inastalled aroind the place i have soldered to without any problem. The sensor is very robust. like any thing electronic that u solder DONT linger there with the soldering bolt get the joint done and let it cool cheers Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Geophone Date: Sat, 03 Jan 1998 15:45:02 I just got a copy of rtclark cataloge. There are two types of geophones. One is called shearwave and the other nothing. I asume the lower freq the better. What kind do I want? Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roger Sorensen Subject: Re: Geophone Date: Sat, 03 Jan 1998 16:40:13 -0800 Norman Davis WB6SHI wrote: > > I just got a copy of rtclark cataloge. There are two types of geophones. > One is called shearwave and the other nothing. I asume the lower freq the > better. > What kind do I want? > > Norman Davis WB6SHI > Email normd@............. > Shingle Springs, Ca, USA it ain't local... Well I'm no expert, but from what I understand "shearwave" is a horizontal sensor while the other "no name" is a vertical sensor. I think in our application, the lower the freq. is the better. I just got my GS-11D geophone in the ground and it seems to work pretty well. Best of luck with yours. Roger - KD6LQE Chatsworth, CA, USA (34.16.23 118.35.62) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Charlie Rond Subject: Re: EMON CONFIGURATION Date: Sat, 03 Jan 1998 19:48:03 -0600 Jim, From my perspective, the Ted Blank software is really a package of components. EMON, of course, is the data monitoring module, QUAKEVIEW (or QUAKEVU) is the display module for a single seismogram, EL lists a group of seismograms for QUAKEVIEW to display, MSPLICE is a utility to "glue" together several files representing a single quake, HOWFAR calculates great circle distance to an epicenter from latitude and longitude, and there are other utilities. If QUAKEVIEW is present, one can display a recorded seismogram from within EMON merely by pressing F8 (and delete, annotate, etc.). The recording can be displayed as a series of data points - as you see on the screen in EMON - or with dots connected by lines (as in WINQUAKE) to any degree of horizontal or vertical compression, etc. P and S points can be picked, comments added, the recording modified and so on. If you have a lot of data files accumulated, EL (QUAKEVIEW) is the fastest way to quickly scan them. My point is that you are not fully utilizing EMON unless you also are using QUAKEVIEW (and EL). As to color: I think the answer is no. By the way, I'm not an "agent" for Ted Blank. I just think he and Larry Cochrane have provided us with some superb software we rarely exploit to full capacity. I'm running both EMON and SDR on different setups and couldn't do without either. --Charlie Rond >> TO: BOB HAMMOND AND ALL LIST MEMBERS >> >> Thanks to the assistance of Bob Hammon I now have EMON up and running. I have >> several questions: >> 1. Is there a way to change the resolution? My screen shows a signal pattern >> with >> the dots Not Connected. I have changed the verticle compression of >> displayed >> signal to 20 and the horizonal to 15 which seemed to help somewhat. >> 2. Is there a way to add color to the screen, even IBM Blue? >> When the program saves the traces and I view it in Winquake the trace is good. >> I am using EMON configured for the CIO-DAS08/Jr 12-bit A/D. >> >> Any suggestions would be appreciated. >> Jim Allen >> Cerritos, California > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) ---------------------------------------------------------------------- Charlie Rond -\/\--Public Seismic Network-Memphis rond@................ (901) 360-0302 [ free BBS ] http://gandlf.ceri.memphis.edu/~rond http://gandlf.ceri.memphis.edu/~rond/psn _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: James Subject: Mammoth Lakes question Date: Sat, 3 Jan 1998 20:36:32 -0600 (CST) Some people explain some "ufo" sightings as ball lightning caused by earthquakes. Are any reports of "lights" coming from Mammoth Lakes? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: Re: EMON CONFIGURATION Date: Sat, 3 Jan 1998 21:44:49 EST TO: CHARLIE ROND Thanks for your advice. I will certainly followup on those suggestions. Jim Allen Cerritos, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Bill Scolnik Subject: Re: Rockland filter Date: Sat, 3 Jan 1998 22:34:15 -0500 (EST) At 09:16 AM 1/1/98 -0500, Robert L Barns wrote: > Hi gang, > Here's something you might look for at a hamfest or on used equipment >lists. I find it a very useful accessory to my Lehman. I got it from Bill >Scolnic. He found it at a hamfest. He uses a Kron-Hite filter which I >think is quite similar. I'm guessing that $100 or so might get one or the >other at a hamfest. > It is a Rockland Systems Corp. adjustable filter, Model 1022F. It is in >a 19" rack mount case 5 1/2" high and is not very heavy. It contains 2 >identical sections and the data below are for each section. > I don't have the manual so the data are my measurements. A switch >selects either low or high pass. There are 3 decimal dials (X.XX) and a >1X, 10X, 100X and 1000X range switch. This allows setting the knee >frequency from 0.01Hz to 9,990 Hz! A switch selects either 0 or 20db gain. > With the knee frequency set at either 0.08Hz or 200Hz, I found that the >slope above the knee of the low pass filter is 24db/octave with no vis. >ripple. Who could ask for anything more? > The output is from DC with an offset in the output of about 5 mV and I >saw no clipping with output voltages up to 9V. The input impedence is 1 >megohm. There is a switch for each section labelled BW-AC. Can anyone >explain this switch? > I don't know the vintage but found it interesting that the active >components look to be all transistors-no op-amps. When I got it, the left >section worked fine but the right section was a mess. Each section >consists of 5 or 6 small (3X4" about) plug-in cards. I started to >troubleshoot the right section by swapping these cards from section to >section but I discovered that one of the cards in the right section was >plugged-in BACKWARDS. Putting this in the right way fixed it. > Since I have only one seismometer, I'm using it set at 0.08Hz with the >two sections in series so that the slope above the knee is 48db/octave. >With my old home-made 6-pole 0.08Hz filter, I could always see some of the >noise peak at 0.016Hz. With 48 db/octave, this peak is not seen. > A filter which is so easily adjusted opens the door to various >experiments. >Happy hunting & Happy New Year! >Bob Barns > > Bob, The BW/AC switch most likely changes the filter configuration from Butterworth to RC. Bill Scolnik > > >_____________________________________________________________________ > >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: Re: VBB Integrator Date: Sat, 3 Jan 1998 23:26:44 -0600 (CST) Barry et al, Your observation of the non-inverting integrator configuration is correct. It is true that most integrators are inverting, but this is just a hangover from early op-amp circuits where everything was using the inverting input. Of course, it is also a low-pass filter of one pole, and is even described in the literature as a "unit-lag" or "running-mean" amplifier. The response of an inverting integrator is: Eout = - 1/(RC)*integral [( Ein - Eout )dt]. It is the same for the non-inverting config, except without the "-" The time constant is R(ohms) x C (farads) in seconds. IF it WERE considered a filter, then the Fc would be 2*pi*R*C, as you observed. But our transfer function needs the time constant, which is actually in radians/second. As for using a single amplifier, a very low input offset and leakage current unit will work, something like the OPA111. I use the instrumentation configuration because with affordable large capacitors (ie electrolytics), leakage currents vary with temperature, etc, and I am trying to minimize all known noise sources. (I also have a box of them left over from monitoring earth currents in the Aleutians, which the Greeks claimed could predict quakes; just a bunch of noise, though). Also the two 2meg resitors should have a low a temp coefficient and be carefully matched so the amp input currents don't vary with temperature. And, of course, it does work as advertised in the 6 VBB circuits I am running with it. I do appreciate the feedback needs for clarifications. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: MAJ EVENT Date: Sun, 04 Jan 1998 19:22:58 +1200 time 06 22 utc 04 jan 98 maje event coming in Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: MA EVENT Date: Sat, 03 Jan 1998 22:34:33 -0800 Amazing, your message arrived about 30 seconds before the P wave arrived here... I was setting at my computer and your message arrived. After reading it, I looked over at my SDR systems and saw nothing. Then all of a sudden the alarm went off.... No S wave yet. -Larry At 07:22 PM 1/4/98 +1200, Dave Nelson wrote: > >time 06 22 utc 04 jan 98 maje event coming in > > >Dave _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Tom Frey" Subject: Re: MA EVENT Date: Sat, 3 Jan 1998 22:45:23 -0800 Same Here!!!! _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ron Westfall Subject: Re: MA EVENT Date: Sat, 03 Jan 1998 22:42:28 -0800 Hi The S waves reached Vancouver, BC about 3 - 4 minutes ago. They are still coming in. Ron Westfall Larry Cochrane wrote: > Amazing, your message arrived about 30 seconds before the P wave arrived > here... I was setting at my computer and your message arrived. After > reading it, I looked over at my SDR systems and saw nothing. Then all of a > sudden the alarm went off.... No S wave yet. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Monster Quake? Date: Sat, 03 Jan 1998 22:49:24 -0700 Any word on where it was yet? -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "frank murray" Subject: RE: MA EVENT Date: Sat, 3 Jan 1998 22:49:14 -0800 if everybody could pop their times and locations into their posts, we could all see the pattern of the waves... > -----Original Message----- > From: Tom Frey [mailto:tfrey@............ > Sent: Saturday, January 03, 1998 10:45 PM > To: PSN-L Mailing List > Subject: Re: MA EVENT > > > Same Here!!!! > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ron Westfall Subject: Re: MA EVENT Date: Sat, 03 Jan 1998 22:59:41 -0800 Hi Vancouver, BC, Canada P: approx. 6:25:00 S: approx. 6:35:45 Ron Westfall frank murray wrote: > if everybody could pop their times and locations into their posts, we could > all see the pattern of the waves... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: MA EVENT Date: Sun, 04 Jan 1998 20:03:29 +1200 ok larry and i actually was ~4 minutes into the event when i mailed u guys tooo bust watching the event come in to mail sooner Dave At 10:34 PM 1/3/98 -0800, you wrote: >Amazing, your message arrived about 30 seconds before the P wave arrived >here... I was setting at my computer and your message arrived. After >reading it, I looked over at my SDR systems and saw nothing. Then all of a >sudden the alarm went off.... No S wave yet. > >-Larry > >At 07:22 PM 1/4/98 +1200, Dave Nelson wrote: >> >>time 06 22 utc 04 jan 98 maje event coming in >> >> >>Dave > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "John Krempasky" Subject: Re: MA EVENT Date: Sun, 4 Jan 1998 02:07:13 -0500 Hmm, interesting, I've been surfing around, nothing on NEIC, this is what I've found so far (I presume this is the seismo) from the Swiss network; they don't have a loc yet. Off the scale, I guess, yes? http://seismo.ethz.ch/networks/telemetry_net/signals/KP199801040631.gif _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Tom Frey" Subject: Re: MA EVENT Date: Sat, 3 Jan 1998 23:12:00 -0800 P approx 06:25:07 @ RM1 (47.456N, 121.803W) 06:25:06 @ GM1 (47.202N, 121.790W) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: MAJ EVENT Date: Sat, 03 Jan 1998 23:11:58 -0800 At 10:59 PM 1/3/98 -0800, you wrote: >Hi > > Vancouver, BC, Canada > P: approx. 6:25:00 S: approx. 6:35:45 Redwood City, Ca USA P: 6:24:50 S: 6:35:20 Based on a depth of 33km distance = 9559km from station and a time of origin of 6:12:12UTC. Magnitude over 7 -Larry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: MA EVENT Date: Sun, 04 Jan 1998 20:11:34 +1200 im posting my event file in a couple of minutes get my p arrival off there Dave At 10:59 PM 1/3/98 -0800, you wrote: >Hi > > Vancouver, BC, Canada > P: approx. 6:25:00 S: approx. 6:35:45 > >Ron Westfall > >frank murray wrote: >> if everybody could pop their times and locations into their posts, we could >> all see the pattern of the waves... > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Once again, it's Vanuatu Islands! Date: Sat, 03 Jan 1998 23:15:11 -0700 Once again, it's Vanuatu Islands! -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com From: Ray Gallagher Subject: Re: MA EVENT Date: Sat, 03 Jan 1998 23:17:07 -0800 e0208c0-w- d o NWS-TSUNAMI-BULLETIN-NUM 01-03 0167 TSUNAMI BULLETIN NUMBER 1 WEST COAST AND ALASKA TSUNAMI WARNING CENTER/NOAA/NWS ISSUED JAN 4 AT 0655 UTC ..THIS IS A TSUNAMI INFORMATION BULLETIN FOR ALASKA, BRITISH COLUMBIA, WASHINGTON, OREGON, AND CALIFORNIA ONLY... NO, REPEAT NO, WATCH OR WARNING IS IN EFFECT. AN EARTHQUAKE, PRELIMINARY MAGNITUDE 7.0, OCCURRED AT 2112 AST ON JAN 3, OR 2212 PST ON JAN 3, OR 0612 UTC ON JAN 4. THE EARTHQUAKE WAS LOCATED IN THE GENERAL AREA OF: SOUTH OF VANUATU NEAR 22.1S, 170.7E. THE PACIFIC TSUNAMI WARNING CENTER WILL ISSUE A TSUNAMI INFORMATION BULLETIN FOR HAWAII AND OTHER AREAS OF THE PACIFIC. EVALUATION: BASED ON LOCATION AND MAGNITUDE THE EARTHQUAKE WAS NOT SUFFICIENT TO GENERATE A TSUNAMI DAMAGING TO CALIFORNIA, OREGON, WASHINGTON, BRITISH COLUMBIA OR ALASKA. SOME AREAS MAY EXPERIENCE SMALL SEA LEVEL FLUCTUATIONS. THIS WILL BE THE ONLY BULLETIN ISSUED FOR THIS EVENT BY THE WEST COAST AND ALASKA TSUNAMI WARNING CENTER UNLESS CONDITIONS WARRANT.IF AVAILABLE, REFER TO THE INTERNET SITE (USE LOWER CASE) HTTP://WWW.ALASKA.NET/(TILDA)ATWC FOR MORE INFORMATION. EDIS-01-03-98 2257 PST _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ray Gallagher Subject: Re: MA EVENT Date: Sat, 03 Jan 1998 23:17:43 -0800 e0209c0-w- d o NWS-TSUNAMI-BULLETIN-NO. 01-03 0141 TSUNAMI BULLETIN NO. 001 PACIFIC TSUNAMI WARNING CENTER/NOAA/NWS ISSUED AT 0701Z 04 JAN 1998 THIS BULLETIN IS FOR ALL AREAS OF THE PACIFIC BASIN EXCEPT CALIFORNIA, OREGON, WASHINGTON, BRITISH COLUMBIA, AND ALASKA. . THIS IS A TSUNAMI INFORMATION MESSAGE, NO ACTION REQUIRED . . AN EARTHQUAKE, PRELIMINARY MAGNITUDE 7.0 OCCURRED AT 0612 UTC 4 JAN 1998, LOCATED NEAR LATITUDE 22S LONGITUDE 171E IN THE VICINITY OF LOYALTY ISLANDS REGION EVALUATION: A PACIFIC-WIDE TSUNAMI WAS NOT GENERATED BASED ON EARTHQUAKE AND HISTORICAL TSUNAMI DATA. THIS WILL BE THE ONLY BULLETIN ISSUED UNLESS ADDITIONAL INFORMATION BECOMES AVAILABLE. . . NO PACIFIC-WIDE TSUNAMI WARNING IS IN EFFECT . . . RECIPIENTS OF THIS MESSAGE LOCATED IN CALIFORNIA, OREGON, WASHINGTON, BRITISH COLUMBIA, AND ALASKA SHOULD REFER ONLY TO ALASKA TSUNAMI WARNING CENTER MESSAGES FOR INFORMATION ABOUT ANY TSUNAMI THREAT IN THOSE AREAS. EDIS-01-03-98 2302 PST _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: vanuatu .... Date: Sun, 04 Jan 1998 20:47:43 +1200 i have a ham radio friend in vanuatu have jst emailed him to see if he felt it will let u know what he says cheers Dave BTW these are the largest P waves i have EVER recorded from this area will be interesting to see the final USGS report have a feeling the Mw will tell the real truth 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: Canie Brooks Subject: Loyalty Islands Date: Sun, 04 Jan 1998 00:03:40 -0800 This is the URL for the event on IDC List: http://www.cdidc.org:65120/web-bin/event/bulletin=AELs/evids=1248641/map_sca le=2 (BTW: Can anyone explain why they are always lower in magnitude than USGS?) Canie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Loyalty Islands Date: Sun, 04 Jan 1998 21:15:12 +1200 At 12:03 AM 1/4/98 -0800, you wrote: >This is the URL for the event on IDC List: >http://www.cdidc.org:65120/web-bin/event/bulletin=AELs/evids=1248641/map_sca >le=2 > >(BTW: Can anyone explain why they are always lower in magnitude than USGS?) > >Canie it is a computer generated report mate they are ALLWAYS extremely low cheers DAve Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Francesco Subject: BIG QUAKE Date: Sun, 04 Jan 1998 10:15:18 +0100 Hi to all, the italian station have registered at 6.33 Utc a big quake. Large P non S and Surface wave. Preliminary location Sud Est Pacific (LOyalty Islands???) Ms =>6.9 Good Day Francesco FRANCESCO NUCERA OSIMO - Ancona - ITALY Lat. 43 29" E - Long. 13 29" E _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Paul Subject: Re: MA EVENT Date: Sun, 04 Jan 1998 02:13:31 -0800 Larry Cochrane wrote: > Amazing, your message arrived about 30 seconds before the P wave arrived > here... I was setting at my computer and your message arrived. After > reading it, I looked over at my SDR systems and saw nothing. Then all of a > sudden the alarm went off.... No S wave yet. > > -Larry > > At 07:22 PM 1/4/98 +1200, Dave Nelson wrote: > > > >time 06 22 utc 04 jan 98 maje event coming in > > > > > >Dave > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L Larry, did you or nyone else pick up something around 1-1:30 PST? I felt a fairly muted but strong tremor in the Sherman Oaks area of So. CA this morning, and went online a bit later to see if there was any news, and lo and behold, you magic Indians had your ears to the ground! Not surprising, I was just wondering if this might be related... We get a lot of these up in the hills, very close along the line of the Northridge fault that took part of this area down in '94... Thanks, (I did get an S wave in my seat at the time...). -- Stephen Paul :^) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Paul Subject: Re: MA EVENT Date: Sun, 04 Jan 1998 02:16:52 -0800 Larry, Actually I see by the time that these messages started appearing, it could have been earlier. I was immersed in a film and stupidly neglected to note the time... I'm sure it must be related. Any news yet? - Stephen :^) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Paul Subject: Re: MA EVENT Date: Sun, 04 Jan 1998 02:19:39 -0800 frank murray wrote: > if everybody could pop their times and locations into their posts, we could > all see the pattern of the waves... > > > -----Original Message----- > > From: Tom Frey [mailto:tfrey@............ > > Sent: Saturday, January 03, 1998 10:45 PM > > To: PSN-L Mailing List > > Subject: Re: MA EVENT > > > > > > Same Here!!!! > > > > > > Tom, As I mentioned to Larry, I didn't get the time, but my house really swayed down here in Sherman Oaks, San Fernando Valley area of So. CA -- Stephen Paul :^) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Paul Subject: Re: MA EVENT Date: Sun, 04 Jan 1998 02:38:31 -0800 I now have checked with my girlfriend and I'm not as crazy as I thought... we actually had a quake down here in So. CA over two hours later... Could these possibly be related? Kate Hutton would tell me that there's no relationship as they're too far away from each other... but I wonder... there's that ringing bell again? -- Stephen :^) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: STM-8 documents Date: Sun, 4 Jan 1998 09:49:55 -0500 Sean-Thomas, I would suggest staying with .GIF format since more people can easliy view this brand of graphics. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Fwd: Caltech's CMT for the Loyality Is. quake Date: Sun, 04 Jan 1998 08:12:41 -0700 Attached below is Caltech's Automatic Centroid Moment Tensor solution for the Loyalty Islands event. It was centered pretty darn close to the intersection of the Hebrides subduction zone and the Hunter Ridge. The orientation of the focal mechanism, however, suggests a better relationship with the Hunter Ridge zone. There was a M7.7 near here on May 16, 1995 - centered slightly closer to Walpole Island. -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com From: "Martin Brewer" Subject: Re: MA EVENT Date: Sun, 4 Jan 1998 00:20:33 -0400 Hello All, Bermuda recorded the Loyalty Islands Region earthquake at a distance of 130 degrees away. What appears to be a SkP arrived at 06:34:33. There was no obvious P wave equivalent. Martin _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: VBB integrator Date: Sun, 4 Jan 1998 11:02:32 -0600 (CST) Barry, I forgot to mention one detail about the integrator: why I use a non-inverting configuration: For the VBB feedback, the integral feedback thru RI can not be inverted with respect to the proportional or differential feedbacks, so if an inverting integrator is used, an additional inverter amp is required between the displacement transducer amp/filter and the inverted integrator input. (This is done on commercial units that provide a full differential output of the VBB signal for 1 bit more of dynamic range.) I stay with a "single ended" system for simplicity. Regards, Sean-THomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: MA EVENT Date: Sun, 04 Jan 1998 09:05:57 -0800 Stephen -- I just uploaded my event file for your felt earthquake... 98/01/04 09:11:45 34.20N 118.62W 0.0 3.2ML 1 mi W of CANOGA PARK Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... At 02:13 AM 1/4/98 -0800, Stephen Paul wrote: > Larry, did you or nyone else pick up something around 1-1:30 PST? I felt a >fairly muted but strong tremor in the Sherman Oaks area of So. CA this >morning, and went online a bit later to see if there was any news, and lo and >behold, you magic Indians had your ears to the ground! Not surprising, I was >just wondering if this might be related... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: The Current Status of Mammoth Date: Sun, 4 Jan 1998 10:51:27 -0800 (PST) Hello All: Here is the latest information about the CURRENT CONDITION of the Mammoth Lakes (Long Valley) caldera as posted by the USGS on their Web Site. ---------------------------------------------------------- Caldera activity: Earthquake activity within the caldera over the past 24 hours included four earthquakes with magnitudes greater than M=3.0. On the evening of the 3rd, M=3.6 and M=3.4 events at 10:19 PM and 10:25 PM, respectively, were located 5 miles east of Mammoth Lakes (near the mouth of Fumarole Valley). On the morning of the 4th, M=3.2 and M=3.6 events at 4:29 AM and 4:34 AM, respectively, were located 2 miles ESE of Mammoth Lakes. All together, 306 earthquakes were detected and located by the realtime computer system over the past 24 hours. Seventeen of these (including the four M>3 earthquakes) had magnitudes of M=2.5 or greater. Most of these earthquakes were located in the south moat from the vicinity of fish hatchery to east of the airport (5 to 7 miles E of Mammoth Lakes) with a smaller number in a cluster just 2 miles ESE of Mammoth Lakes. The resurgent dome continues to inflate at about the same rate as observed in late-October and early November. ---------------------------------------------------------- Frank Condon mail to:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Marnie Gannon Subject: ISAIAH AUTOMATIC DATA SUMMARY FOR EVENT ID=9038429 Date: Sun, 04 Jan 1998 12:47:11 -0700 Hey Guys, could you tell me what this is, in easy speak? Thanks, Marnie http://www-socal.wr.usgs.gov/given/review/quakes/9038429_sum.html From: shammon1@............. Subject: Re: ISAIAH AUTOMATIC DATA SUMMARY FOR EVENT ID=9038429 Date: Sun, 04 Jan 1998 14:53:30 -0800 This is the Southern Californa automatic earthquake locator system. It is an example of the state of the art in cool web pages. Take a look at http://www-socal.wr.usgs.gov/given/review/quakes/9038516_sum.html because it also includes the event data which is missing on the URL you posted. I'm told that it is also tied to a pager system but I've yet to so one. Maybe somebody has more information. Regards, Steve Hammond PSN BBS San Jose Marnie Gannon wrote: > > Hey Guys, could you tell me what this is, in easy speak? > Thanks, Marnie > http://www-socal.wr.usgs.gov/given/review/quakes/9038429_sum.html > > --------------------------------------------------------------- > > ISAIAH AUTOMATIC DATA SUMMARY FOR EVENT ID=9038429 > > ON THIS PAGE, JUMP TO... > > [Seismograms] [Notification Message] [Solution Output] [Phase Listing] > [Return to TOP] > > [BACK TO EARTHQUAKE LIST] > > Seismograms of closest stations (sorted by distance) > ---------------------------------------------------------------------- > > [Image] > > WHAT THE PLOT SHOWS: > > * Closest 15 sites with phase picks > * 60 Seconds of time > * Event origin time is 10 sec after beginning of plot > > [Seismograms] [Notification Message] [Solution Output] [Phase Listing] > [Return to TOP] > > [BACK TO EARTHQUAKE LIST] > > ---------------------------------------------------------------------- > > Notification message > > ---------------------------------------------------------------------- > > == PRELIMINARY REPORT OF SIGNIFICANT EVENT == > Southern California Seismographic Network operated by USGS and Caltech > (This is a computer generated solution and has not been reviewed by a human) > > Event Date and Time : 04-JAN-1998 09:32:40.5 gmt (04-JAN 01:32:40.5 pst) > Preliminary Magnitude: 2.2 MGN > Preliminary Location : 35 deg. 37.0 min. > -120 deg. 30.4 min. -6.0 km depth > > Event ID #: 9038429 , 8 phases used, RMS = 0.63 ERH = 2.50 ERZ = 52.50 > > 20 mi. SSW of PARKFIELD > 168 mi. NW of PASADENA > 14 mi. NNE of SANTA-MARGARITA (quarry) > 21 mi. S of Parkfield EQ (28 JUN 1966, 5.6) > 9 mi. WNW of the RINCONADA FAULT > > [Seismograms] [Notification Message] [Solution Output] [Phase Listing] > [Return to TOP] > > [BACK TO EARTHQUAKE LIST] > > ---------------------------------------------------------------------- > > HYPOINVERSE solution output > > ---------------------------------------------------------------------- > > ERROR ELLIPSE: -< 52.50 0 90>-< 2.50 226 0>-< 1.77 316 0> > ------------------------------------------------------------------------------------ > YR MO DA --ORIGIN-- --LAT N- --LON W-- DEPTH RMS ERH ERZ XMAG FMAG > 98- 1- 4 0932 40.48 35 36.99 120 30.40 6.00 0.63 2.50 52.50 > SOURCE > NSTA NPHS DMIN MODEL GAP ITR NFM NWR NWS NVR REMRKS N.XMG-XMMAD-T N.FMG-FMMAD-T L F X > 11 11 50.7 HAD 121 14 0 8 0 11 - 0.00 0.00 0.00 0.00 > REGION= FALX LOCATION: 9038429 > > STA CR DIST AZM AN P/S WT SEC (TOBS -TCAL -DLY =RES) WT SR INFO CAL DUR-W-FMAG-T AMP-PER-W-XMAG-T RMK > PBI 50.7 176 90 P 49.71 9.23 8.53 0.00 0.70* 1.05 0.313 > PSM 51.0 351 90 P 1 50.43 9.95 8.58 0.00 1.37* 0.66 0.240 > PPB 52.3 221 90 P 49.65 9.17 8.79 0.00 0.38 1.05 0.472 > YEG 53.3 112 90 P 49.67 9.19 8.94 0.00 0.25 1.05 0.705 > SIM 54.8 122 90 P 49.66 9.18 9.18 0.00 0.00 1.05 0.930 > PHC 58.9 278 90 P 49.65 9.17 9.84 0.00 -0.67* 1.05 0.470 > PRI 60.1 347 90 P 50.37 9.89 10.03 0.00 -0.14 1.05 0.580 > BCH 61.2 141 90 P 49.68 9.20 10.20 0.00 -1.00* 1.05 0.286 > PTQ 115.3 183 90 S 70.55 30.07 33.43 0.00 -3.36* 0.00S 0.000 > MTU 261.0 42 53 P 70.59 30.11 38.53 0.00 -8.42* 0.00 0.000 > MTC 263.9 31 53 P 70.67 30.19 38.90 0.00 -8.71* 0.00 0.000 > > [Seismograms] [Notification Message] [Solution Output] [Phase Listing] > [Return to TOP] > > [BACK TO EARTHQUAKE LIST] > > ---------------------------------------------------------------------- > > Phase picks (HYPOINVERSE format) > > ---------------------------------------------------------------------- > > PHC IPU0 98 1 4 93249.65 P VHZ 1225 0 > PPB IPD0 98 1 4 93249.65 P VHZ 1094 0 > YEG IPD0 98 1 4 93249.67 P VHZ 952 0 > SIM IPU0 98 1 4 93249.66 P VHZ 742 0 > BCH IPU0 98 1 4 93249.68 P VHZ 1026 0 > PBI IPU0 98 1 4 93249.71 P VHZ 2132 0 > PSM IPU1 98 1 4 93250.43 P VHZ 625 0 > PRI IPD0 98 1 4 93250.37 P VHZ 1019 0 > PTQ 98 1 4 933 10.55ISD0 S VHZ 1322 0 > MTC IPU0 98 1 4 93310.67 P VLZ 1722 0 > MTU IPU0 98 1 4 93310.59 P VHZ 767 0 > 932404835 3699120 3040 6.00 9038429 9038429 0.00 > > [Seismograms] [Notification Message] [Solution Output] [Phase Listing] > [Return to TOP] > > [BACK TO EARTHQUAKE LIST] > > ---------------------------------------------------------------------- > [Image] Return to USGS homepage _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Caruso Subject: Re: ISAIAH AUTOMATIC DATA SUMMARY FOR EVENT ID=9038429 Date: Sun, 4 Jan 1998 19:54:07 -0500 (EST) Marnie, I don't know if anybody else has a problem with your message (if they don't then ignore this one)but there is alot of html language aboard. I have noticed an html option in the software but if that's what you intended I'll have to load it into a browser off this 8088. Thanks for the bandwidth. STEPHEN CARUSO CET KB8UGH "Coincidence is a shortsighted mental delusion" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Caruso Subject: Re: ISAIAH AUTOMATIC DATA SUMMARY FOR EVENT ID=9038429 Date: Sun, 4 Jan 1998 20:20:39 -0500 (EST) Don't get me wrong, I am enthused w/every PSN message. I just thought you weren't aware of what was coming across the net. Thanks for posting.:^) STEPHEN CARUSO CET KB8UGH "Coincidence is a shortsighted mental delusion" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Trading Post? Date: Sun, 04 Jan 1998 20:19:39 -0700 Hi everyone, This is tentative in thought...Is anyone interested in trading whatever for whatever?? I know for myself... I have a surplus of old stuff I'll likely never get around to using. Expect there is afew out there in the same surplus condition, who would treasure someone else's endless storage goodies. This avocation cost can be considerable over a period of time and a swap may bring a faster and cheaper solution than commercial approaches. Guess it would be fun too. I'am sure that an endless email approach is not desired over the PSN machine. Perhaps, for those interested they could privately communicate outside PSN per their own individual email. It should be possible to make it a swap only....no cash involved....except for postage costs. Anyway....being as this is just a thought...what do you think? Rules? Limitations? Gone Fishing in this PSN pond.........?? Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Marnie Gannon Subject: Re: ISAIAH AUTOMATIC DATA SUMMARY FOR EVENT ID=9038429 Date: Sun, 04 Jan 1998 21:23:46 -0700 Stephen Caruso wrote: > > Don't get me wrong, I am enthused w/every PSN message. I just thought you > weren't aware of what was coming across the net. Thanks for posting.:^) Sorry, you guys, for some reason the seismogram didn't send on the page link..What it was..not what is showing in your post, was a series of tremors on one 60 second plot..I think it showed about 4 8-10 second events, separated by smaller periods with no signal at all..each of the tremors seemed to have its own p wave, not sure about s.. Darn, wish I could show it to you. The entire quake has been deleted now... so I can't send it as a link or anything. Still about 70 or so deleted links on the page for Parkfield and San Luis Obispo quakes...I'm assuming these are bad locations for Mammoth quakes... The ISAIAH site is great..I refer to it often, just lately alot of odd links, deleted, etc.. You hadtohavebeenthere I guess! Sorry about the posting snafu.. Marnie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: kathy mortensen Subject: DATAQ DI-150RS Date: Sun, 04 Jan 1998 21:01:09 -0700 O.K. I just found the PSN mailing list about 3 weeks ago and have been glued to my email. I was intriged with Sean Thomas Idea of using the Radio Shack dvm as a data recorder. I've been looking for an economical way to record my seimograph signals. When I checked with Radio Shack I discovered their data logger. I ordered it and received it on the 9th working day (UPS) the day before new years eve. You know what I've been doing ---no partying--- !!! I did learn a lot about com ports and IRQs!! With a mouse on com-1 IRQ-4 and a modem on com-2 IRQ-3, both activated in windows, I was stuck!! I tried ever combination of com amd IRQs --- with lockup,lockup,lockup#!%@ I down loaded the sample qbasic program from the dataq web site and finally got it to respond --- sometimes --- . It sometimes missed the respond signal and would --guess what-- yes, lockup#%$#@! Next I decided to disable the modem in windows -- we won't go into that story. The easy way turned out to be to load a short version of windows into a separate directory ---fun,fun,fun%$#@! loaded the dataq software --- guess what -- does not respond!!! FINALLY to the point of this story!! I downloaded the latest software from their web site (as they put it - if you have problems) daaa!! YES,YES,YES --- it works!!! The best data logger I ever had --- of course it is also the worst -- it's the only one!!! I have nothing to compare it to!!! At this point I suspect that I am not compatible with anyone!! At last I can record waveforms. I was on line when the loyalty set off my alarm but I was in the standby mode %$#@#$!!!! but I did catch the end of it and the two mammoths at approx. 4:30 A.M. A long story but hopefully helpful to anyone considering getting a DATAQ. Stephen K. Mortensen here after SKM email mortskm@....... Pilot Hill, Calif. USA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: Re: Trading Post? Date: Mon, 5 Jan 1998 00:41:37 EST MEREDITH LAMB Your trading post idea is great. I say lets go for it. Jim Allen Cerritos, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Re: DATAQ DI-150RS Date: Sun, 04 Jan 1998 22:44:23 I was intriged with Sean Thomas Idea of using the Radio Shack >dvm as a data >recorder. I have been using the rs dvm for loging for a while now and find the sapling rate to slow. 1 sec but it does work and is great for trouble shooting and designing amps and filters. I and mike d have been thinking of the dataq modual for this purpose and intersted in your post. > I was on line when the loyalty set off my alarm but I was >in the standby >mode %$#@#$!!!! but I did catch the end of it and the two mammoths at >approx. 4:30 A.M. What is loyalty?? >A long story but hopefully helpful to anyone considering getting a >DATAQ. I could use it for other stuff like radio astomomy and weather data but think I will put any further money into a good adc board as then I can use a program like emon or sdr. Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: PSN records for M. Antolik - Map / MPEG viewers Date: Sun, 04 Jan 1998 23:03:34 -0800 Greetings, Does anyone know of a MPEG viewer that can display the files at the link below. All of the Win95/NT versions I can find on the Net either won't display the pictures correctly or need to be registered to display the large files. While I'm at it... I'm also looking for a good commercial street map program that can be used to display the location of local or regional events. A long time ago I had a Windows 3.1 program called LocalExpert. It was limited in what it could do but was OK for locating local events. It would allow you to draw circles of X diameter so one could plot the event location based on the P and S wave distance from several stations. Unfortunately I lost that program a while back when I had a hard disk crash. I now do regular backups... I now have a program called Precision Mapping 2.0. Its not very good. It only displays distance in miles, no km, and drawing of a circle is real flaky. So if anyone can suggest a good MPEG view and / or map program please let me know. Regards, Larry Cochrane Redwood City, PSN At 02:53 PM 1/2/98 -0700, Edward Cranswick wrote: >PSN members in the San Francisco Bay Area- > 3-dimensional, finite-difference models of seismic wave propagation and >site response in the San Francisco Bay Area created by members of the >Seismic Station at UCB can be seen: > >http://www.seismo.berkeley.edu/seismo/events_of_interest/3dmod/3dmod.html > >-Edward _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: kathy mortensen Subject: Re: DATAQ DI-150RS Date: Sun, 04 Jan 1998 23:35:29 -0700 What is loyalty?? > LOYALTY ISLANDS REGION was the reference that USGS gave for a 7.0 earthquake N.E. of astralia -- 22.17S, 170.51E Jan 4 06:11:50 1998 GMT About 6,100 miles from here! > Norman Davis WB6SHI > Email normd@............. > Shingle Springs, Ca, USA it ain't local... > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "frank murray" Subject: RE: PSN records for M. Antolik - Map / MPEG viewers Date: Mon, 5 Jan 1998 00:06:12 -0800 > -----Original Message----- > From: Larry Cochrane [mailto:cochrane@............... > Sent: Sunday, January 04, 1998 11:04 PM > To: PSN-L Mailing List > Subject: Re: PSN records for M. Antolik - Map / MPEG viewers > > > Greetings, > > Does anyone know of a MPEG viewer that can display the files at the link > below. All of the Win95/NT versions I can find on the Net either won't > display the pictures correctly or need to be registered to display the > large files. > i tried the ones for the hayward fault and found that the smaller two (about ..2 mbyte and .5 mbyte) would run under ie4, but not the larger one...i suspect that updating my version of RUNDLL32 should do it...the updates are usually available at the ms site...i'll let you know if that works...and thanks for the cue to the site...cool movies... frank _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: PSN records for M. Antolik - Map / MPEG viewers Date: Mon, 05 Jan 1998 05:55:02 -0600 Larry Cochrane wrote: > While I'm at it... I'm also looking for a good commercial street map > program that can be used to display the location of local or regional > events. A long time ago I had a Windows 3.1 program called LocalExpert. It > was limited in what it could do but was OK for locating local events. It > would allow you to draw circles of X diameter so one could plot the event > location based on the P and S wave distance from several stations. > Unfortunately I lost that program a while back when I had a hard disk > crash. I now do regular backups... I now have a program called Precision > Mapping 2.0. Its not very good. It only displays distance in miles, no km, > and drawing of a circle is real flaky. > > So if anyone can suggest a good MPEG view and / or map program please let > me know. > > Regards, > Larry Cochrane > Redwood City, PSN Larry, We have been using software and data from DeLorme Mapping Co. at work for our GPS tracking system. I can find out more about how well it works today from the guys that are actually using it. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "frank murray" Subject: anything at 12:50 UTC??... Date: Mon, 5 Jan 1998 05:15:25 -0800 did anyone pick up something just prior to 12:50 UTC on 1/5/98??... frank _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: ralvarez@........ (Raul Alvarez) Subject: Re: Trading Post? Date: Mon, 5 Jan 1998 06:34:06 -0700 (MST) Greetings! Great idea!! I sure have a lot of junk, er, treasure, I can swap. Why not also post your needed items? Raul >Hi everyone, > >This is tentative in thought...Is anyone interested in trading >whatever for whatever?? I know for myself... I have a >surplus of old stuff I'll likely never get around to using. > >Expect there is afew out there in the same surplus condition, >who would treasure someone else's endless storage goodies. > >This avocation cost can be considerable over a period of >time and a swap may bring a faster and cheaper solution >than commercial approaches. Guess it would be fun too. > >I'am sure that an endless email approach is not desired over >the PSN machine. Perhaps, for those interested they >could privately communicate outside PSN per their own >individual email. It should be possible to make it a swap >only....no cash involved....except for postage costs. > >Anyway....being as this is just a thought...what do you >think? Rules? Limitations? Gone Fishing in this PSN >pond.........?? > >Thanks, Meredith Lamb > > > > > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~ ~ ~ "My dreams are the seeds of my reality, ~ ~ nurtured in the womb of my soul" ~ ~ RJA, 1985 ~ ~ ~ ~ ~ ~ Raul J. Alvarez ~ ~ Bellvue, Colorado ~ ~ e-mail ralvarez@........ ~ ~ homepage www.frii.com/~ralvarez ~ ~ "The Renaissance Experimenter" ~ ~ experimenter in: ~ ~ Radio and Optical Astronomy, Seismology, Weather, ~ ~ Computers, Instrumentation and Neat Stuff! ~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Mike Lozano Subject: Re:Trading Post! Date: Mon, 05 Jan 1998 08:54:54 -0600 Hi guys! Trading post sounds like a great idea! Why don't I kick things off with two offerings: 1 ea. FastVac DV-85/DV-142 Series Deep Vacuum Pump BRAND NEW - NEVER EVEN PLUGGED IN! with spare Wankel-type cylinder replacement kit (still in box), and 1 Qt. of oil (still sealed). Purchased for around $400 for a project that never got off the ground. Great for micro-barometry experimenters! 2 ea. DRSI Micro Data Link Controllers (packet radio system) Licensed on commercial itinerant frequency in the 460 MHz band (5 watt transmitter and cut-to-frequency rubber duck antennas on BNC connectors. This system uses commercial packet standard, and is not easily compatible with amateur packet. Used, but in MINT condition. Purchased for around $1500. Set up your own remote seismic station! Mike Lozano, N0BDF mikel@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: ISAIAH AUTOMATIC DATA SUMMARY FOR EVENT ID=9038429 Date: Mon, 05 Jan 1998 07:35:27 -0700 Stephen Caruso wrote: > > Don't get me wrong, I am enthused w/every PSN message. I just thought you > weren't aware of what was coming across the net. Thanks for posting.:^ I can understand your frustration, Steve. It has been my experience that different web browsers interpret web sites differently and it is the same for e-mail readers as well. When Marnie attaches the html document, many modern e-mail readers, like Netscape, Explorer, Claris, etc., can interpret the html language and format the message in a full html document with font enhancements, links and graphics. Quite a wonderful invention, really! I used it extensively when publishing Seismo-Watch Earthquake Alert Bulletins via e-mail. However, the draw back is many people do not use these modern e-mail readers and it can be a bother when all they see is a bunch of html scripting. They really don't know what they are missing and it can be frustrating to get all the gibberish html. I have found it is best when passing information from other web sites to simply provide the html link and if people are really interested, they can go to the web site and see it for themselves. Cheers! -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Re: PSN records for M. Antolik - Map / MPEG viewers Date: Mon, 05 Jan 1998 07:31:27 >While I'm at it... I'm also looking for a good commercial street map >program that can be used to display the location of local or regional >events. A long time ago I had a Windows 3.1 program called LocalExpert. It >was limited in what it could do but was OK for locating local events. It >would allow you to draw circles of X diameter so one could plot the event >location based on the P and S wave distance from several stations. >Unfortunately I lost that program a while back when I had a hard disk >crash. I now do regular backups... I now have a program called Precision >Mapping 2.0. Its not very good. It only displays distance in miles, no km, I have the newer version 3.0 it and it seems to me that it will do km and the circles look good, IMHO. Norm Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Trading Post! Date: Mon, 05 Jan 1998 07:57:37 -0700 Hey this is a great idea! Maybe a web page could be set up at the PSN web site that could deal with these "treasures". Call it the "PSN Trading Post". -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: PSN records for M. Antolik - Map / MPEG viewers Date: Mon, 05 Jan 1998 09:44:12 -0700 Larry- I think that I am using a plugin from Intervu, http://www.intervu.net/ though I am somewhat confused about what is going on when I try to track down the details of my instalation of Netscape Navigator Gold ver 3.01. -Edward Larry Cochrane wrote: > > Greetings, > > Does anyone know of a MPEG viewer that can display the files at the link > below. All of the Win95/NT versions I can find on the Net either won't > display the pictures correctly or need to be registered to display the > large files. -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: dean sevold Subject: Fwd: Meteorite News Date: Mon, 05 Jan 98 08:49:27 PST Date: Sun, 04 Jan 98 16:11:05 PST From: Klaus Georg Hansen To: dean sevold Subject: Meteorite News Dear Dean Last news from Greenland (KNR): Today (4th) 10.000 km2 has been overflewn by an airplane with the special radar. On the plane were a crew of 11 specialists. The area overflewn is between Groennedal to the south and Nuuk to the north. Radar operator Soeren Madsen Danish Technical University told KNR they saw nothing from the plane that with certainty was a meteorite, but something might be interpreted as a strike area. Now all the data from the radar must be analysed on computers in Denmark before anytning new can be said. These analysis might last for a week or so. Klaus Georg Hansen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Marnie Gannon Subject: Re: PSN records for M. Antolik - Map / MPEG viewers Date: Mon, 05 Jan 1998 10:04:31 -0700 Edward Cranswick wrote: > > Larry- > I think that I am using a plugin from Intervu, > > http://www.intervu.net/ Edward, Just went over and looked at the site. Do you find it true that it speeds graphics downloads by two or three times? Marnie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: ERICH777 Subject: Event So CA Date: Mon, 5 Jan 1998 13:20:31 EST To : psn-l@............. Subject: Time: Date: Jan 5 approx 10 :14 Station Location 33,51.00N 118,8.33W Remarks; P to S 24 miles away A n George Erich ~~~~~~~|~~~~~~~~~~/~~~~~ Seismic Exploration Consulting Services '' ' ' ' ' ' ' 'O' " ' ' ' ' '` ' ' ' ' /' ' ' ' ' ' ' P. O. Box 2011 ` ` ` ` ` ` ` \ ` ` `` ` ' '` ` / ` ` ` ` ` ` Norwalk, CA 90651-2011 USA . . . . . . . . \ . . . . . . / . . . . . . - - - - - - - - -\ - - - - -/ - - - - - - - Telephone (562) 868-6013 : : : : : : : : : \ : :' ::/ : : : : : : : e-mail GeE777@....... \ / ' ' ' ' ' ' ' ' ' ' ' ' '.\ ' / " " " " " " " Psalms 85:11 Truth shall spring out of the earth; . . . .. ___V___________ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: ERICH777 Subject: Re; Geophone Date: Mon, 5 Jan 1998 13:12:05 EST Hi all Date: 98-01-03 18:49:16 EST normd@............. (Norman Davis WB6SHI) writes; << I just got a copy of rtclark cataloge. There are two types of geophones. One is called shearwave and the other nothing. I asume the lower freq the better.>> I have used the GSC-11D geophone in work with exploration seismology. Don't worry about soldering, I'ts made for that. The notrhing is a vertical phone. I suggest RT Ckark used seismic equipment catalog at ( rtclark@........... ) for inexpensive equipment. Remember, most of their stuff is for seismic exploration and they record higher frequency seismic signals. A n George Erich ~~~~~~~|~~~~~~~~~~/~~~~~ Seismic Exploration Consulting Services '' ' ' ' ' ' ' 'O' " ' ' ' ' '` ' ' ' ' /' ' ' ' ' ' ' P. O. Box 2011 ` ` ` ` ` ` ` \ ` ` `` ` ' '` ` / ` ` ` ` ` ` Norwalk, CA 90651-2011 USA . . . . . . . . \ . . . . . . / . . . . . . - - - - - - - - -\ - - - - -/ - - - - - - - Telephone (562) 868-6013 : : : : : : : : : \ : :' ::/ : : : : : : : e-mail GeE777@....... \ / e-mail ERICH777@....... ' ' ' ' ' ' ' ' ' ' ' ' '.\ ' / " " " " " " " Psalms 85:11 Truth shall spring out of the earth; . . . .. ___V___________ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "frank murray" Subject: RE: Event So CA Date: Mon, 5 Jan 1998 10:52:04 -0800 this from usgs: 98/01/05 18:14:06 33.94N 117.71W 7.8 4.3Ml SOUTHERN CALIFORNIA > -----Original Message----- > From: ERICH777 [mailto:ERICH777@........ > Sent: Monday, January 05, 1998 10:21 AM > To: psn-l@............. > Subject: Event So CA > > > To : > psn-l@............. > Subject: > Time: > > Date: Jan 5 approx 10 :14 > > > Station Location > 33,51.00N > 118,8.33W > > Remarks; > P to S 24 miles away > > > A n > George Erich > ~~~~~~~|~~~~~~~~~~/~~~~~ > Seismic Exploration Consulting Services '' ' ' ' ' ' ' 'O' " ' ' ' ' '` > ' ' ' ' /' ' ' ' ' ' ' > P. O. Box 2011 ` ` ` ` ` ` ` \ ` ` > `` ` ' '` ` / ` ` ` ` ` ` > Norwalk, CA 90651-2011 USA . . . . . . . . \ . . . . .. . > / . . . . . . > - - - - - - > - - -\ - - - - -/ - - - - - - - > Telephone (562) 868-6013 : : : : : : : : : \ : :' > ::/ : : : : : : : > e-mail GeE777@....... \ / > ' ' ' ' ' ' > ' ' ' ' ' ' '.\ ' / " " " " " " " > Psalms 85:11 Truth shall spring out of the earth; . . . .. ___V___________ > > > > _____________________________________________________________________ > > 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@................. (Bob Hammond (USGS-AVO Geophysicist)) Subject: Re: Geophone Date: Mon, 5 Jan 1998 09:51:54 -0900 Norman Davis, et al: I use a Mark Products L4 geophone which is sold by the RT Clark, Co. I suggest using this geophone as a short-period vertical sensor for amateur seismographs because it a 1-Hz seismometer, has good response, and is used by virtually all of the university and government seismograph networks in the US. Keep in mind that geophones normally used in oil exploration are 2 Hz geophones and are not as good for monitoring regional and local earthquakes as a 1 Hz instrument. The L4 comes with a calibration coil and is marked as a L4-C. You don't need the cal coil. regards, Bob Hammond APSN Fairbanks (- 43F this morning) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: PSN records for M. Antolik - Map / MPEG viewers Date: Mon, 05 Jan 1998 12:16:37 -0700 Marnie- I don't know, i.e., I have not done any benchmark tests; against what? -Edward Marnie Gannon wrote: > > Edward Cranswick wrote: > > > > Larry- > > I think that I am using a plugin from Intervu, > > > > http://www.intervu.net/ > > Edward, > > Just went over and looked at the site. Do you find it true that it > speeds graphics downloads by two or three times? > > Marnie > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Paul Subject: Re: MA EVENT Date: Mon, 05 Jan 1998 10:36:03 -0800 Karl Cunningham wrote: > Stephen -- > > I just uploaded my event file for your felt earthquake... > > 98/01/04 09:11:45 34.20N 118.62W 0.0 3.2ML 1 mi W of CANOGA PARK > > Karl Cunningham > La Mesa, CA. > PSN Station #40 > karlc@....... > > At 02:13 AM 1/4/98 -0800, Stephen Paul wrote: > > Larry, did you or nyone else pick up something around 1-1:30 PST? I felt a > >fairly muted but strong tremor in the Sherman Oaks area of So. CA this > >morning, and went online a bit later to see if there was any news, and lo and > >behold, you magic Indians had your ears to the ground! Not surprising, I was > >just wondering if this might be related... > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L Thanks Karl... I'm really beginning to suspect the interrelatedness of these events all over the world, and most especially on the opposite sides of the rim. We had a real shaker again this morning at about 02:20 UTC. Preliminary reports I've seen say it was a 4.1 centered in Chino, CA... I suspect it isn't the end... my house felt like a 747 landing for close to 30-45 seconds! Apparently this one was widely felt... There are so many fractures down here that sometimes it's hard to tell just what is happening, i.e. is it a big one far off or a small one close by? A lot depends on how the P wave feels. The sharper the jolt, the closer it usually is. But I guess the length of duration of the S is what causes the mondo damage. And Italy seems to be still having more than its share of woes. Did you happen to map this morning's event? Appreciate the reply. Thanks. -- Stephen :^) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Paul Subject: Re: PSN records for M. Antolik - Map / MPEG viewers Date: Mon, 05 Jan 1998 11:11:27 -0800 Larry Cochrane wrote: > Greetings, > > Does anyone know of a MPEG viewer that can display the files at the link > below. All of the Win95/NT versions I can find on the Net either won't > display the pictures correctly or need to be registered to display the > large files. > > While I'm at it... I'm also looking for a good commercial street map > program that can be used to display the location of local or regional > events. A long time ago I had a Windows 3.1 program called LocalExpert. It > was limited in what it could do but was OK for locating local events. It > would allow you to draw circles of X diameter so one could plot the event > location based on the P and S wave distance from several stations. > Unfortunately I lost that program a while back when I had a hard disk > crash. I now do regular backups... I now have a program called Precision > Mapping 2.0. Its not very good. It only displays distance in miles, no km, > and drawing of a circle is real flaky. > > So if anyone can suggest a good MPEG view and / or map program please let > me know. > > Regards, > Larry Cochrane > Redwood City, PSN > > At 02:53 PM 1/2/98 -0700, Edward Cranswick wrote: > >PSN members in the San Francisco Bay Area- > > 3-dimensional, finite-difference models of seismic wave propagation and > >site response in the San Francisco Bay Area created by members of the > >Seismic Station at UCB can be seen: > > > >http://www.seismo.berkeley.edu/seismo/events_of_interest/3dmod/3dmod.html > > > >-Edward > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L Larry, do you know what type or layer MPEG it is? If it's MJPEG this could be the problem, and I do have solutions for most everything viewable... might it be in DVD format? That could cause difficulty too. I have a Post setup in my shop and can steer you to a solution most likely. I'll pop over the link also and see what I can find out and hopefully let you know something within a few days. Keep your fingers crossed... I'm also a computer dealer on the side, and if you can find out who wrote or manufactured the map program, I will check through my distributors for what you need and get it to you wholesale... Let me know if I can help. -- Stephen :^) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Paul Subject: Re: PSN records for M. Antolik - Map / MPEG viewers Date: Mon, 05 Jan 1998 11:40:19 -0800 Larry Cochrane wrote: > Greetings, > > Does anyone know of a MPEG viewer that can display the files at the link > below. All of the Win95/NT versions I can find on the Net either won't > display the pictures correctly or need to be registered to display the > large files. > > While I'm at it... I'm also looking for a good commercial street map > program that can be used to display the location of local or regional > events. A long time ago I had a Windows 3.1 program called LocalExpert. It > was limited in what it could do but was OK for locating local events. It > would allow you to draw circles of X diameter so one could plot the event > location based on the P and S wave distance from several stations. > Unfortunately I lost that program a while back when I had a hard disk > crash. I now do regular backups... I now have a program called Precision > Mapping 2.0. Its not very good. It only displays distance in miles, no km, > and drawing of a circle is real flaky. > > So if anyone can suggest a good MPEG view and / or map program please let > me know. > > Regards, > Larry Cochrane > Redwood City, PSN > > At 02:53 PM 1/2/98 -0700, Edward Cranswick wrote: > >PSN members in the San Francisco Bay Area- > > 3-dimensional, finite-difference models of seismic wave propagation and > >site response in the San Francisco Bay Area created by members of the > >Seismic Station at UCB can be seen: > > > >http://www.seismo.berkeley.edu/seismo/events_of_interest/3dmod/3dmod.html > > > >-Edward > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L Larry, I successfully played the movie with the built in Media Player in Win 95... Haven't checked the 32 bit ver. in NT yet, but in 95 (Build 950a-IOW Sevice pack 1 installed for 95, available from the MS site) it ran fine. I do have Mpeg decoders built in all over the place, but try that and let me know if it plays. If not, I'll check my System.ini and find out what module is being used to play it besides Rundll, and see if I can send you a copy. Most of my MPEG stuff is distributable. -- Stephen :^) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: MA EVENT Date: Mon, 05 Jan 1998 12:46:29 -0700 Stephen- You appear to be in a very sensitive site for picking up events -- and this makes sense in terms of the concentrated pattern of damage to Sherman Oaks by the Northridge Earthquake. What is your address? -Edward Stephen Paul wrote: > > frank murray wrote: > > > if everybody could pop their times and locations into their posts, we could > > all see the pattern of the waves... > > > > > -----Original Message----- > > > From: Tom Frey [mailto:tfrey@............ > > > Sent: Saturday, January 03, 1998 10:45 PM > > > To: PSN-L Mailing List > > > Subject: Re: MA EVENT > > > > > > > > > Same Here!!!! > > > > > > > > > > > Tom, > > As I mentioned to Larry, I didn't get the time, but my house really swayed down > here in Sherman Oaks, San Fernando Valley area of So. CA > -- > Stephen Paul :^) > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Global M5+ Activity - record tying sequence Date: Mon, 05 Jan 1998 13:17:21 -0700 As I was preparing this week's Seismo-Watch Global Earthquake Report for December 21-27, 1997, I noticed there have been 8 consecutive weeks of 20+ earthquakes registering M5 or stronger. (Week: Sunday through Satruday; Time: GMT; Source: NEIC QED and PDE files) Sustained activity at this level is uncommon happenning only 3 prior times in the last 5 years (twice in 1995 and from Feb - Apr earlier in 1997). I have not looked in the PDE catalogs prior to 1992, but does anyone know how often this has occurred before this and if there have ever been 9 consecutive weeks of 20+ earthquakes registering M5 or stronger? -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Walt Williams" Subject: Re:Trading Post! & Suggestions Date: Mon, 5 Jan 1998 14:12:40 +0000 Hello PSN-L, The idea of a 'Trading Post' is an interesting idea. In the tradition of technical reflectors, items for swap / sale are typically listed seperate to avoid clogging the 'data' channel. Perhaps the PSN-L host could be asked nicely to provide a separate list or web space? If not, and depending upon traffic (as I am busy these days), I will offer some web page space for PSN-L list members to post their offerings / wants. I pose a question: fellow PSN-Ls, do we really want 'spam' co-mingled with normal dialog of the list? Best Regards, Walt Williams, 98.01.05 dfheli@.............. http://www.pacificnet.net/~dfheli Canoga Park, (LA suburb), California USA ===================================================== ------- Forwarded Message Follows ------- Date: Mon, 05 Jan 1998 08:54:54 -0600 From: Mike Lozano Reply-to: PSN-L Mailing List Organization: Applied Sciences, Ltd. To: PSN-L Mailing List Subject: Re:Trading Post! Hi guys! Trading post sounds like a great idea! Why don't I kick things off with two offerings: 1 ea. FastVac DV-85/DV-142 Series Deep Vacuum Pump BRAND NEW - NEVER EVEN PLUGGED IN! with spare Wankel-type cylinder replacement kit (still in box), and 1 Qt. of oil (still sealed). Purchased for around $400 for a project that never got off the ground. Great for micro-barometry experimenters! 2 ea. DRSI Micro Data Link Controllers (packet radio system) Licensed on commercial itinerant frequency in the 460 MHz band (5 watt transmitter and cut-to-frequency rubber duck antennas on BNC connectors. This system uses commercial packet standard, and is not easily compatible with amateur packet. Used, but in MINT condition. Purchased for around $1500. Set up your own remote seismic station! Mike Lozano, N0BDF mikel@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: lahr@.................. Subject: exploration geophones Date: Mon, 5 Jan 1998 15:44:09 -0700 (MST) On my web site I give some information on obtaining a free exploration geophone from Arlen Juels of Seistex `86 Inc. These are used phones that would probably work fine for local earthquake monitoring. http://www.giseis.alaska.edu/Input/lahr/web.sites.html#GEOPHONES 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://www.aeic.alaska.edu/lahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Marnie Gannon Subject: LA peak velocties/acceleration Date: Mon, 05 Jan 1998 16:34:00 -0700 Don't know if you all know about this page: http://www-socal.wr.usgs.gov/pga.html It's a prototype which has computer generated contour maps of 1. Peak Velocity 2. Peak Acceleration 3. Focal Mechanism and 4. Individual station info for Southern California. The Chino earthquake is up now. Most significant local EQs will show up in about 5 minutes.. Marnie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: evans@.................... (John Evans) Subject: ADXL-05 info Date: Mon, 5 Jan 98 16:00:00 PST Edward, Please post the following info for the PSN folks. It's recent price and availability for the ADXL05 accel (a fairly noisy but interesting device good for demos at least). Some may be interested: Distributors: 800-463-9275 Subject: Re: DATAQ DI-150RS Date: Mon, 5 Jan 1998 16:45:12 -0800 I'm pretty new to all this monitoring, and been thinking about the DATAQ logger. But I don't have the COM1 conflicts that you do. Since you dint specify what computer you are using, is it possible your motherboard has a PS/2 connector on it? If so, you either buy a PS/2 mouse or get an adapter cable to convert your RS-232 mouse to a PS/2 mouse and free up that RS-232 port! BTW, the RS232 mice are the slowest ones and that is why so many folks use the PS/2 connector. Now, the bit question: What device is the input to your DATAQ card? and is it the DATAQ software that gives you the "alarm" you talk about? Dennis Eckert KB7ST (Amateur Radio Operator) Flies Standard Cirrus sailplane (SV) In Western & Eastern Washington ICQ 4324132 -----Original Message----- From: kathy mortensen To: psn-l@............. Date: Sunday, January 04, 1998 9:03 PM Subject: DATAQ DI-150RS >O.K. I just found the PSN mailing list about 3 weeks ago and have been >glued to my >email. I was intriged with Sean Thomas Idea of using the Radio Shack >dvm as a data >recorder. I've been looking for an economical way to record my >seimograph signals. >When I checked with Radio Shack I discovered their data logger. I >ordered it and >received it on the 9th working day (UPS) the day before new years eve. >You know what >I've been doing ---no partying--- !!! I did learn a lot about com >ports and IRQs!! >With a mouse on com-1 IRQ-4 and a modem on com-2 IRQ-3, both activated >in windows, I >was stuck!! I tried ever combination of com amd IRQs --- with >lockup,lockup,lockup#!%@ >I down loaded the sample qbasic program from the dataq web site and >finally got it to >respond --- sometimes --- . It sometimes missed the respond signal and >would --guess >what-- yes, lockup#%$#@! Next I decided to disable the modem in >windows -- we won't >go into that story. The easy way turned out to be to load a short >version of windows >into a separate directory ---fun,fun,fun%$#@! loaded the dataq >software --- guess >what -- does not respond!!! FINALLY to the point of this story!! I >downloaded >the latest software from their web site (as they put it - if you have >problems) daaa!! > YES,YES,YES --- it works!!! The best data logger I ever had --- >of course it >is also the worst -- it's the only one!!! I have nothing to compare >it to!!! >At this point I suspect that I am not compatible with anyone!! At >last I can record >waveforms. I was on line when the loyalty set off my alarm but I was >in the standby >mode %$#@#$!!!! but I did catch the end of it and the two mammoths at >approx. 4:30 A.M. >A long story but hopefully helpful to anyone considering getting a >DATAQ. > >Stephen K. Mortensen here after SKM >email mortskm@....... >Pilot Hill, Calif. 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: watson@................ (Charles Watson) Subject: Re: LA peak velocties/acceleration Date: Mon, 05 Jan 1998 17:00:33 -0700 Marnie Gannon wrote: > > Don't know if you all know about this page: > > http://www-socal.wr.usgs.gov/pga.html > > It's a prototype which has computer generated contour maps of 1. Peak > Velocity 2. Peak Acceleration 3. Focal Mechanism and 4. Individual > station infofor Southern California. The Chino earthquake is up now. > Most significant local EQs will show up in about 5 minutes.. Thanks for redirecting my attention to the site. My felt reports from the region suggest the acceleration map is pretty good. I got sharply felt reports from Chino, Sierra Madra and San Gabriel Valley (to the NNW) as well as from the Riverside region (to the SE), but every one else did not feel it as sharply. -- interesting. -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Marnie Gannon Subject: Re: LA peak velocties/acceleration Date: Mon, 05 Jan 1998 18:21:04 -0700 Charles Watson wrote: > > > Thanks for redirecting my attention to the site. My felt reports from > the region suggest the acceleration map is pretty good. I got sharply > felt reports from Chino, Sierra Madra and San Gabriel Valley (to the > NNW) as well as from the Riverside region (to the SE), but every one > else did not feel it as sharply. -- interesting. Same here Charles, Friends and news reports say it was a sharp, 3-4 second, jolting quake. I didn't notice the first time that when you click on the triangles the ind.station info comes up..Check out Seal Beach! Marnie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: TESMECO Subject: Re: Trading Post? Date: Mon, 5 Jan 1998 20:48:49 EST good idea _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Paul Subject: Re: MA EVENT Date: Mon, 05 Jan 1998 18:04:37 -0800 Edward Cranswick wrote: > Stephen- > You appear to be in a very sensitive site for picking up events -- and > this makes sense in terms of the concentrated pattern of damage to > Sherman Oaks by the Northridge Earthquake. What is your address? > -Edward > > Stephen Paul wrote: > > > > frank murray wrote: > > > > > if everybody could pop their times and locations into their posts, we could > > > all see the pattern of the waves... > > > > > > > -----Original Message----- > > > > From: Tom Frey [mailto:tfrey@............ > > > > Sent: Saturday, January 03, 1998 10:45 PM > > > > To: PSN-L Mailing List > > > > Subject: Re: MA EVENT > > > > > > > > > > > > Same Here!!!! > > > > > > > > > > > > > > > > Tom, > > > > As I mentioned to Larry, I didn't get the time, but my house really swayed down > > here in Sherman Oaks, San Fernando Valley area of So. CA > > -- > > Stephen Paul :^) > > > > _____________________________________________________________________ > > > > Public Seismic Network Mailing List (PSN-L) > > > > To leave this list email listserver@............. with the body of the > > message: leave PSN-L > > -- > Edward Cranswick Tel: 303-273-8609 > US Geological Survey, MS 966 Fax: 303-273-8600 > PO Box 25046, Federal Center cranswick@........ > Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L Edward, I am in the hills about 1 block E. of Woodman, and a mile or so south, and I would guess at an elevation of roughly 800-1200 ft. above the boulevard. Though many felt the event was 3-4 seconds, up here I definitely felt motion for 30-45 seconds. And you are so right. I can feel even the slightest tremors up here, which is a characteristic of being in the hills, mostly bedrock I believe, though more damage resulted here than in Studio City hills, my former residence for 10 years... I guess it's like being at the end of a stick where you can really fell the motion. What do you think of the 'ringing bell' hypothesis put forward some years ago? I tend to believe it... I read aboout it in an article in Scientific American some 6-7 years ago. Are you aware of it? -- Stephen :^) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: LA peak velocties/acceleration Date: Mon, 05 Jan 1998 21:43:34 -0700 Charlie & Marnie- Where are you getting your felt reports from? -Edward Marnie Gannon wrote: > > Charles Watson wrote: > > > > > Thanks for redirecting my attention to the site. My felt reports from > > the region suggest the acceleration map is pretty good. I got sharply > > felt reports from Chino, Sierra Madra and San Gabriel Valley (to the > > NNW) as well as from the Riverside region (to the SE), but every one > > else did not feel it as sharply. -- interesting. > > Same here Charles, > > Friends and news reports say it was a sharp, 3-4 second, jolting quake. > I didn't notice the first time that when you click on the triangles the > ind.station info comes up..Check out Seal Beach! > > Marnie > > _____________________________________________________________________ > > 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: ERICH777 Subject: Re: Geophone Date: Mon, 5 Jan 1998 23:59:06 EST Most exploration geophones have a natural frequency above 8 to 10 HZ. The primary reason for this is to get rid of "ground roll "so it doesn't saturate the amplofiers. I don't envy your temperature at Fairbanks, Bob. I pulled a few winters on the North Slope. First time was the winter of 1948/1949. Seismic exploration for the Navy on NPR4 Regards, < A n Subject: Re: MA EVENT Date: Mon, 05 Jan 1998 21:34:02 -0800 Stephen -- I'm no expert in statistics, to say for sure that there is a relation between events across the globe would take quite a bit of statistical (computer) crunching. But, I think it's true that peoples brains (massive networks of neural nodes) are capable of discerning patterns that would take a lot of crunching by conventional computers to identify. And too, I've seen my brain (and others') be fooled by what appears to be a correlation and really isn't. I guess what I'm saying is that I'm not ready to say that these seeming correlations are anything abnormal, statistically. I've just uploaded my trace of this morning's Chino event. -- Karl At 10:36 AM 1/5/98 -0800, you wrote: >I'm really beginning to suspect the interrelatedness of these events all over the >world, and most especially on the opposite sides of the rim. > >And Italy seems to be still having more than its share of woes. Did you happen to >map this morning's event? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "frank murray" Subject: RE: Global M5+ Activity - record tying sequence Date: Mon, 5 Jan 1998 21:45:40 -0800 > -----Original Message----- > From: Charles Watson [mailto:watson@................. > Sent: Monday, January 05, 1998 12:17 PM > To: Public Seismic Network Mailing List > Cc: QUAKE-L Earthquake Discussion List > Subject: Global M5+ Activity - record tying sequence > > I have not looked in the PDE catalogs prior to 1992, but does anyone > know how often this has occurred before this and if there have ever been > 9 consecutive weeks of 20+ earthquakes registering M5 or stronger? > hmmm...how far back might we trust the catalogs to be complete on M5 quakes??... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Marnie Gannon Subject: Re: LA peak velocties/acceleration Date: Mon, 05 Jan 1998 22:55:41 -0700 Edward Cranswick wrote: > > Charlie & Marnie- > Where are you getting your felt reports from? Edward, Since I live in Montana, I didn't feel it. ;^> I correspond with a number of people in the CA/LA area..seemed most people felt it first as a vibration and then a single jolt. If you need some felt reports from these areas I could probably gather them for you.. Marnie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: new zealand a shaking Date: Tue, 06 Jan 1998 18:54:58 +1200 wow guys 3 unrelated events in one day all good size M4.5 and greater in the South Island of New Zealand. the latest only 1 hr befor this mail posted was so far the largest, they have been getting bigger as the day rolls on this is putting January 1997 to shame Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: LA peak velocties/acceleration Date: Mon, 05 Jan 1998 22:21:22 -0700 Edward Cranswick wrote: > > Charlie & Marnie- > Where are you getting your felt reports from? Edward, I prepare professional regional and global earthquake graphics/reports for newspapers and television, and a few for the public as well. I have a pretty large following and get felt reports via phone, fax and the internet from domestic and worldwide sources. -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Global M5+ Activity - record tying sequence Date: Mon, 05 Jan 1998 22:24:57 -0700 frank murray wrote: > > > > > I have not looked in the PDE catalogs prior to 1992, but does anyone > > know how often this has occurred before this and if there have ever been > > 9 consecutive weeks of 20+ earthquakes registering M5 or stronger? > > > > hmmm...how far back might we trust the catalogs to be complete on M5 > quakes??... > probably 1960's, better as time goes on. For a while, I tracked M4+ events, but that went the way of the buffalo during the 1995 round of NEIC budget cuts. -- ---/---- Charles P. Watson _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Walt Williams" Subject: Re: MA EVENT Date: Tue, 6 Jan 1998 03:38:33 +0000 Hello All, For any one interested. I live in Canoga Park, which is a suburb of Los Angeles, California. The city sandwiched between Northridge and Chatsworth. Sherman Oaks, is located East of these three cities. We 'felt' 20...30 seconds of sharp shaking, which was preceded with a loud bang sound. Often, I 'feel' events minutes before I start to see posts here on the PSN-L. I have been quiet about posting comments about these 'felt' events as there is little useful data to be gained. My house is located slightly west of center of the so-called 'Valley' in the San Fernando Valley. Walt Williams, 98.01.06 dfheli@.............. Canoga Park, (LA suburb), California USA ------- Forwarded Message Follows ------- Date: Mon, 05 Jan 1998 18:04:37 -0800 From: Stephen Paul Organization: Built On Dreams To: PSN-L Mailing List Subject: Re: MA EVENT Reply-to: PSN-L Mailing List Edward Cranswick wrote: > Stephen- > You appear to be in a very sensitive site for picking up events -- and > this makes sense in terms of the concentrated pattern of damage to > Sherman Oaks by the Northridge Earthquake. What is your address? > -Edward > > Stephen Paul wrote: > > > > frank murray wrote: > > > > > if everybody could pop their times and locations into their posts, we could > > > all see the pattern of the waves... > > > > > > > -----Original Message----- > > > > From: Tom Frey [mailto:tfrey@............ > > > > Sent: Saturday, January 03, 1998 10:45 PM > > > > To: PSN-L Mailing List > > > > Subject: Re: MA EVENT > > > > > > > > > > > > Same Here!!!! > > > > > > > > > > > > > > > > Tom, > > > > As I mentioned to Larry, I didn't get the time, but my house really swayed down > > here in Sherman Oaks, San Fernando Valley area of So. CA > > -- > > Stephen Paul :^) > > > > _____________________________________________________________________ > > > > Public Seismic Network Mailing List (PSN-L) > > > > To leave this list email listserver@............. with the body of the > > message: leave PSN-L > > -- > Edward Cranswick Tel: 303-273-8609 > US Geological Survey, MS 966 Fax: 303-273-8600 > PO Box 25046, Federal Center cranswick@........ > Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L Edward, I am in the hills about 1 block E. of Woodman, and a mile or so south, and I would guess at an elevation of roughly 800-1200 ft. above the boulevard. Though many felt the event was 3-4 seconds, up here I definitely felt motion for 30-45 seconds. And you are so right. I can feel even the slightest tremors up here, which is a characteristic of being in the hills, mostly bedrock I believe, though more damage resulted here than in Studio City hills, my former residence for 10 years... I guess it's like being at the end of a stick where you can really fell the motion. What do you think of the 'ringing bell' hypothesis put forward some years ago? I tend to believe it... I read aboout it in an article in Scientific American some 6-7 years ago. Are you aware of it? -- Stephen :^) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Charlie Rond Subject: Re: web page Date: Mon, 05 Jan 1998 20:10:28 -0600 Sean-Thomas, You are doing good work and I am enjoying your Web Page. I've included a link to your vertical on the PSN-Memphis Web Page under "construction." Charlie Rond -\/\--Public Seismic Network-Memphis rond@................ (901) 360-0302 [ free BBS ] http://gandlf.ceri.memphis.edu/~rond http://gandlf.ceri.memphis.edu/~rond/psn _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ted Blank Subject: Re: Trading Post! & Suggestions Date: Tue, 6 Jan 1998 07:22:55 -0800 (PST) I think the trading post is a great idea. I hope it can be kept separate from the discussions on the list so it will be quicker to scan the list of items for trade. Also, that list should have lower volume so would stay around longer. Regards, Ted > > Hello PSN-L, > > The idea of a 'Trading Post' is an interesting idea. In > the tradition of technical reflectors, items for swap / sale are > typically listed seperate to avoid clogging the 'data' channel. > Perhaps the PSN-L host could be asked nicely to provide a > separate list or web space? If not, and depending upon traffic (as I > am busy these days), I will offer some web page space for PSN-L list > members to post their offerings / wants. > > I pose a question: fellow PSN-Ls, do we really want 'spam' > co-mingled with normal dialog of the list? > > Best Regards, > > Walt Williams, 98.01.05 > dfheli@.............. > http://www.pacificnet.net/~dfheli > > Canoga Park, (LA suburb), California > USA > > ===================================================== > > ------- Forwarded Message Follows ------- > Date: Mon, 05 Jan 1998 08:54:54 -0600 > From: Mike Lozano > Reply-to: PSN-L Mailing List > Organization: Applied Sciences, Ltd. > To: PSN-L Mailing List > Subject: Re:Trading Post! > > Hi guys! > Trading post sounds like a great idea! Why don't I kick things off > with two offerings: > > 1 ea. FastVac DV-85/DV-142 Series Deep Vacuum Pump > BRAND NEW - NEVER EVEN PLUGGED IN! with spare Wankel-type cylinder > replacement kit (still in box), and 1 Qt. of oil (still sealed). > Purchased for around $400 for a project that never got off the ground. > Great for micro-barometry experimenters! > > 2 ea. DRSI Micro Data Link Controllers (packet radio system) Licensed > on commercial itinerant frequency in the 460 MHz band (5 watt > transmitter and cut-to-frequency rubber duck antennas on BNC > connectors. This system uses commercial packet standard, and is not > easily compatible with amateur packet. Used, but in MINT condition. > Purchased for around $1500. Set up your own remote seismic station! > > Mike Lozano, N0BDF > mikel@....... > > > _____________________________________________________________________ > > 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: watson@................ (Charles Watson) Subject: Re: (Fwd) Re: MA EVENT Date: Tue, 06 Jan 1998 07:38:14 -0700 Thanks for the felt report, Walt. I use the felt reports in my Seismo-Watch earthquake reports - of course, just giving the regions it was felt and the extent of shaking. Since I am way up here in Reno, I often do not find out if the smaller (M3) temblors in California were felt sometimes till much later. With the Northern and Southern California offices of the USGS discontinuing their weekly earthquake bulletins there will be a significant loss of felt earthquake reports available to the public. I am concerned about this and have voiced my concerns to the appropriate parties. I would greatly appreciate an e-mail message if anyone feels an earthquake, no matter how big or small, or where ever you are on the planet. -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Mike Lozano Subject: Seismic system Date: Tue, 06 Jan 1998 10:02:16 -0600 I'm sure it's not news to the "pro's" in the bunch, but my company did some work with the Bureau of Reclamation recently. They maintain their own seismographic system for Dam Safety. http://seismo.usbr.gov/quake/curWus.html covers Colorado, Wyoming and Idaho, as I recall. Mike Lozano, N0BDF -0- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: bob@................. (Bob Hammond (USGS-AVO Geophysicist)) Subject: Re: oil exploration geophones Date: Tue, 6 Jan 1998 07:55:59 -0900 I know a seismologist who attempted to use oil exploration geophones (a pair, actually) in lieu of 1 Hz seismometers for his regional seismic network. While they did indeed respond to very local earthquakes, their output was just not adequate due to the mass and coil being so small. By the way, my hat's (but not my coat, it's still too cold here) off to Sean Thomas for his design and construction of his VBB seismometer! It's "way cool"! I might just have to build a few and put them in the schools I work with instead of the short-period verticals I use now. George Erich: I'd like to hear more about your winter experiences on NPR4 in 48/49. regards to all, Bob Hammond APSN Fairbanks _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: lahr@.................. Subject: mpeg player Date: Tue, 6 Jan 1998 10:24:41 -0700 (MST) I found that the VMPEG viewer listed on this page worked well with Windows 95. http://www.mpeg.org/pointers/MPEG-video-player.html I was able to view the video that Edward mentioned, located at: http://www.seismo.berkeley.edu/seismo/events_of_interest/3dmod/3dmod.html The player that comes with Windows 95 did not work for me. I also tried one called MPEGPLAY. It only displayed a black and white picture for the small video's and required a $25 registration to play a larger video! The earthquake videos are in color and look great with the free VMPEG viewer. JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: kathy mortensen Subject: Re: DATAQ DI-150RS Date: Tue, 06 Jan 1998 14:27:25 -0700 Dennis Eckert wrote: > > I'm pretty new to all this monitoring, and been thinking about the DATAQ > logger. But I don't have the COM1 conflicts that you do. Since you dint > specify what computer you are using, is it possible your motherboard has a > PS/2 connector on it? If so, you either buy a PS/2 mouse or get an adapter > cable to convert your RS-232 mouse to a PS/2 mouse and free up that RS-232 > port! > > BTW, the RS232 mice are the slowest ones and that is why so many folks use > the PS/2 connector. > > Now, the bit question: What device is the input to your DATAQ card? and is > it the DATAQ software that gives you the "alarm" you talk about? > > Dennis Eckert KB7ST (Amateur Radio Operator) > Flies Standard Cirrus sailplane (SV) > In Western & Eastern Washington > > ICQ 4324132 > -----Original Message----- > From: kathy mortensen > To: psn-l@............. > Date: Sunday, January 04, 1998 9:03 PM > Subject: DATAQ DI-150RS > > >O.K. I just found the PSN mailing list about 3 weeks ago and have been > >glued to my > >email. I was intriged with Sean Thomas Idea of using the Radio Shack > >dvm as a data > >recorder. I've been looking for an economical way to record my > >seimograph signals. I have a clone, no PS/2 connection. I'm using com4 IRQ5 --so far no problems, except, I can't log and go on the web or even use my regular windows! Eventually I want to get a dedicated system. The bit answer: The DATAQ is a module that has a cable to connect to a serial port (9 pin) (I use an adapter and connect to my spare 25 pin serial port, the one I had to disable to hook up my modem -- long story). The alarm that I was refering to is on my amplifier board. I don't know enough about the DATAQ software yet to know if they have any alarms, well except for the beep for file full. If I find any, I'll post! The DATAQ DI-150RS is a 2 ch. (or 1 ch. differential) with a therm 1 and 2, (which I haven't figured out yet) and an excitation input (up to 15 volts) with an excit + and - for use with a bridge network. More as I learn!! SKM ICQ 6314138 email mortskm@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Re: Geophone Date: Mon, 05 Jan 1998 20:39:31 >I use a Mark Products L4 geophone which is sold by the RT Clark, Co. I suggest using this geophone >as a short-period vertical sensor for amateur seismographs because it a 1-Hz seismometer, has good >response, and is used by virtually all of the university and government seismograph networks in >the US. Well bob keep mind the word amature. At 375 a piece I can get a lot of 4 hz phones for that price. Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: bob@................. (Bob Hammond (USGS-AVO Geophysicist)) Subject: Re: Geophone Date: Tue, 6 Jan 1998 14:53:08 -0900 Norm Davis: Yes, I agree the L4 is high cost compared to 4 Hz geophones. TANSTAAFL. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: Global M5+ Activity - record tying sequence Date: Tue, 06 Jan 1998 08:28:37 -0800 Frank I agree with Charles. It may go back to the mid 40's in the US. Barry Charles Watson wrote: > > ---/---- > Charles P. Watson > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: PSN records for M. Antolik - Map / MPEG viewers Date: Wed, 07 Jan 1998 00:31:13 -0800 Thanks for everyone's help. I was able to use the MPEG viewer at http://www.intervu.net/. This Netscape plug-in worked just fine on the larger MPEG files. Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: yet another good sthrn new zealand event Date: Thu, 08 Jan 1998 01:55:25 +1200 Hi all, SW offshore NZ rocking again, these events really show the ability of 4.5 Hz geophone to perform excellently for local and regional quakes These events are all around 390 to 420km (240 to 260 miles) from my home/sensors the 6 quakes I have recorded in the last 2 days have all been captured by the geophones with no trouble at all. I highly recomend geophones for local and regional activities as their small size, ease of installation, zero maintenance and low cost make them invaluable for amateur activities. They also make a perfect companion to other low freq. teleseismic sensors such as the Lehman seismometer. Cheers Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: bob@................. (Bob Hammond (USGS-AVO Geophysicist)) Subject: Dave Nelson email about 4.5 Hz geophones Date: Wed, 7 Jan 1998 08:48:17 -0900 Sorry, folks, I was obviously wrong about 4.5 Hz geophones being worth using! I based my opinion on my one and only exposure to using them for regional seismograph networks. I stand corrected, Bob Hammond APSN Fairbanks "think twice, email once" (a spin on that old carpenter's rule) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: ERICH777 Subject: Another Small Southern California Event Date: Wed, 7 Jan 1998 14:13:09 EST Hello All Time: 09:50 Date: 98/01/07 Station Location 33,51.00N 118,8.33W Remarks; P delta time to S indicates about 18 miles from me Magnetude M3.XX ? I was away from home when this event occurred and heard about it on my car radio. I did record it with my 4.5 HZ geophone. < A n Subject: 1 hz from 4.5 hz phones; Date: Wed, 7 Jan 1998 13:41:27 -0600 (CST) They can be used for lower frequency work by using very low noise amplifiers to make a 2-pole low pass filter with a gain of about 100, with a corner at 1hz or less. Also, there is a better equalizer circuit board you could get from Sprengnether Instruments Co. (314 535 1682) that is based on an article by P.M.Roberts in BSSA, vol 79, No. 4, Oct 1989. It makes the 4.5 hz phone response look like the L4-C. I don't know what it costs, but it might be around $50. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Marchal, Lare van" Subject: 1 hz from 4.5 hz phones; Date: Wed, 7 Jan 1998 17:36:52 -0500 > They can be used for lower frequency work by using very low noise amplifiers to make a 2-pole low pass filter with a gain of about 100, with a corner at 1hz or less. < = I use this kind of filter with my 4.5 Hz geophones. Last month they detected the two Jan Mayen events (both M5+) about 1800 Km north of my home here in Holland. Bye for now, Marchal van Lare Nieuwvliet, Holland 51.38 N 3.50 E _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roger Sorensen Subject: Re: 1 hz from 4.5 hz phones; Date: Wed, 07 Jan 1998 15:53:24 -0800 Is there somewhere we can find out more about this filter/amp setup? Any Web pages? Thanks Roger (KD6LQE) Chatsworth, CA USA > They can be used for lower frequency work by using very low noise > amplifiers to make a 2-pole low pass filter with a gain of about 100, > with a corner at 1hz or less. > > I use this kind of filter with my 4.5 Hz geophones. Last month they > detected the two Jan Mayen events (both M5+) about 1800 Km north > of my home here in Holland. > > Marchal van Lare _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jeff Batten Subject: test-ignore Date: Wed, 7 Jan 1998 20:15:37 -0800 (PST) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: 1 hz from 4.5 hz phones; Date: Thu, 08 Jan 1998 17:43:24 +1200 At 05:36 PM 1/7/98 -0500, you wrote: They can be used for lower frequency work by using very low noise >amplifiers to make a 2-pole low pass filter with a gain of about 100, >with a corner at 1hz or less. >I use this kind of filter with my 4.5 Hz geophones. Last month they >detected the two Jan Mayen events (both M5+) about 1800 Km north >of my home here in Holland. Bye for now, Marchal van Lare >Nieuwvliet, Holland >51.38 N 3.50 E Hmmmm Marchal by cutting off at 1 Hz u are loosing a lot of valuable seismic data. Local and regional events are very rich in higher freq signal. I far more reccomend a 10Hz filter and then u dont miss that data if the event is teleseismic with a mainly lower freq content then u can use software filtering to get rid of any higher freq manmade noise that may be present i would not even consider using a 1 hz filter myself as u are really defeating the good ability of the geophone also most of the geophones have very severe low freq attenuation (that is they dont respond well) below their resonant freq. so their output there is very low. for ur thoughts 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: "Al Allworth" Subject: Re: L4 Geophone Date: Wed, 7 Jan 1998 21:15:33 -0800 -----Original Message----- From: Bob Hammond (USGS-AVO Geophysicist) To: psn-l@............. Date: Monday, January 05, 1998 10:58 AM Subject: Re: Geophone > Norman Davis, et al: > >I use a Mark Products L4 geophone which is sold by the RT Clark, Co. I suggest using this geophone >as a short-period vertical sensor for amateur seismographs because it a 1-Hz seismometer, has good >response, and is used by virtually all of the university and government seismograph networks in >the US. Keep in mind that geophones normally used in oil exploration are 2 Hz geophones and are not >as good for monitoring regional and local earthquakes as a 1 Hz instrument. The L4 comes with a >calibration coil and is marked as a L4-C. You don't need the cal coil. > >regards, > >Bob Hammond Has anyone seen the internal construction of the L4 geophone? I have several 1 Hz. units and was wondering if a displacement transducer could be added to enable a force feedback conversion. How is the calibration loop used with the L4? Mine are labeled "Seismometer". I have seen others labeled geophone. Is there a difference or only the application? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Marchal, Lare van" Subject: Re: 1 hz from 4.5 hz phones; Date: Thu, 8 Jan 1998 10:19:16 -0500 Dave Nelson wrote: > by cutting off at 1 Hz u are loosing a lot of valuable seismic data. Local and regional events are very rich in higher freq signal. < Yes , Dave, I totally agree with you. Last month I experimented for some time to see what would happen when I use a 1 Hz-filter with 4.5 Hz geophones. I was very surprised to see my seismo was able to detect M5's at 1800 Km.= Cheers, Marchal van Lare Nieuwvliet, Holland (51.38 N 3.50 E) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: 1 hz from 4.5 hz phones; Date: Thu, 8 Jan 1998 00:19:47 -0600 (CST) The response of a geophone rolls off with omega**2 below its' natural frequency. so the voltage output of a 4.5 hz phone is down by a factor of 20 at 1 hz which is where regional and teleseismic p-waves show up. A contour filter or the better equalizer circuit makes up for this loss, the idea is not to attenuate the high frequency response, but to bring up the lower frequency response to a useful level above the electronic noise or the lsb of the DAC. When the fc is properly selected (somewhat below 1 hz, per the math), the 4.5 hz phone will look like a 1 hz phone. This in no way reduces its' high frequency response. We use 1 hz phones for data from 0.1 to 30 hz for regional network stations; ground motion studies require the broader response. Regards, Sean-Thomas St. Louis University _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: 1 hz from 4.5 hz phones; Date: Thu, 08 Jan 1998 08:15:31 -0800 Hi -- I've not tried this circuit with phones, but it should work. It is a basic 2-pole low-pass non-inverting topology. This, along with an amplifier before it should compensate for the second-order roll off of the geophone. Using a third-order filter (add another resistor and capacitor -- I can provide component values if anyone wants) will provide high-frequency attenuation too, if this is desired. Many filter characteristics are in common use. Bessel provides linear phase-to-frequency relationship around the cutoff frequency, which tends to preserve the "look" of the resulting waveform. The values for a two-pole Bessel filter are calculated as follows: C1 = 0.6667F C2 = 0.5F R1 = R2 Choose a value for R1 and R2 that is high -- say 10K or 100K. Now, for desired cutoff frequency f, multiply the above capacitor values by 1/R*w, where R is the chosen resistor values, and w is 2*pi*f. So, for f = 4.5Hz and R1=R2=10K, C1=2.36uF, and C2=1.77uF. | | C1 +------| |----------------+ | | | | | |\ | R2 | R2 | \ | o----\/\/\-+--\/\/\--|-----|+ \ | | | \ | --- | >---++------------o C2 --- | / | | +--|- / | | | | / | | | |/ | | | | | +-----------+ | --- \ / V For the amplifier stage, I'd put it before the filter so the drift of the filter stage is not being amplified too. Just use a good low-drift op-amp. Gain is R1/(R1+R2). |\ | \ o--------------------------|+ \ | \ | >---+-------------o | / \ +--|- / / | | / \ R1 | |/ / | | +-----------+ | \ / \ R2 \ | --- \ / V Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: 1 hz from 4.5 hz phones; Date: Thu, 08 Jan 1998 09:21:51 -0800 Ooops. There must be a correlary to Murphy's law that says I won't realize my mistakes until they are published... I had the wrong idea about conditioning the response of the geophones. What is really needed is for the cutoff frequency of the filter to be set to the low frequency of the desired response (1Hz in the example), and the gain of the amplifier stage be set to make up the difference (20:1, in this case), as Sean-Thomas has suggested. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: L4 fedback? Date: Thu, 8 Jan 1998 11:30:03 -0600 (CST) Bob, Al, and co., I have been overhauling L4-C seismometers for the past 23 years, and I have a collection of them in various states of (dis)repair. The usual problem is that the suspension sags over time, and the internal spacers have to be rearranged to raise the mass, which is difficult to do and still retain the 1-second To. (A temporary solution to a sagging mass is to tilt the seis about 10 degrees, until the mass centering tester indicates it is off the bottom stop). Other problems are the fine connection to the cal coil (I always use them) get fried from accidental contact with a voltage, or the whole thing gets sparked up when lightning hits the telemetry antenna and tries to find ground through the seis by puncturing the thick ABS pipe it is installed in. I tried to use the L4 with feedback several years ago, using the VRDT transducer (the LVDT won't work because the mass rotates slightly as it moves with the multiple circular leaf-spring suspension.) THe problem I had was that all my L4s have 5500 ohm coils, which is way too much resistance for the feedback coil: the response becomes an oscillator, even using half the coil. Mark Products has made low resistance coils, but they are hard to find. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: 4.5hz equalizer Date: Thu, 8 Jan 1998 11:52:06 -0600 (CST) For improving the response below To, I strongly recommend looking at the article : "A Versatile Equalization Ciruit for Increasing Seismometer Velocity Response Below the Natural Frequency", P.M.Robarts, BSSA, Vol 79, No 4, Oct. 1989. For proper equalization of the response, a unity gain amplifier is used in parallel with the low pass stage, so that the response above the filter is restored; the output of the parallel stages is then summed with another amplifier. But using a second-order low pass to correct the omega**2 rolloff presents phase problems near zero voltage (see the article), so two stages are used, but with only first order (single pole) filters, and each with its' parallel unity gain follower and summing amplifier. So a total of 6 amplifiers is needed, which is why a 2-pole low-pass filter is a partial solution; it, however, does not restore the higher frequency response. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Doug Crice Subject: Re: 4.5hz equalizer Date: Thu, 08 Jan 1998 10:01:30 -0800 The response curve of a geophone looks roughtly like this: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx x x | x | db x f x x x x where f is the natural frequency of the pendulum. The behavior at the corner varies with the damping from an upward peak (underdamped) to a smoother rolloff (overdamped). The slope of the attenuation curve is 12 db/octave. So, to make it look more like a 1 Hz geophone, you need to feed the signal through a filter which flattens the response. Something that looks like this: x x x x x db x f x | x xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx You want the gain of this filter to be 1 (well constant anyway) above the natural frequency, and you want increasing gain below that frequency with a slope of +12 db/octave. This should theoretically extend the frequency response of the geophone indefinitely downward until of course noise becomes as big as the signal. For example, at 0.25 Hz, you would need about 48 db of gain just to get a flat response. Karl's 2-pole lowpass (high cut) circuit is not strictly correct; it has the slope but the flat spot is in the wrong place. xxxxxxxxxxxxxxxxxxxxxxx x x x x db x x x x So, depending on where the corner is, you don't get the low boost and you lose the high frequencies. I would guess that the article Sean refers to has the right circuit. Doug Crice _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roger Baker Subject: Re: L4 fedback? Date: Thu, 08 Jan 1998 12:31:51 -0600 Friends, I am not familiar with specific geophones, but the ones I have seen in the literature have something like a alnico cylinder magnet hanging vertically from a springy suspension and inside the high resistance sensing coil. Would it not be possible to wind a tubular low resistance feedback coil on the outside of the geophone, assuming a geophone is really that simple in principle? The instantaneous power demand on such a coil might be high and might require watts of peak output, but the average power demand should be low. Comments? --Yours, Roger Baker At 11:30 AM 1/8/98 -0600, you wrote: >I tried to use the L4 with feedback several years ago, using the VRDT >transducer (the LVDT won't work because the mass rotates slightly as it >moves with the multiple circular leaf-spring suspension.) THe problem >I had was that all my L4s have 5500 ohm coils, which is way too much >resistance for the feedback coil: the response becomes an oscillator, >even using half the coil. Mark Products has made low resistance coils, >but they are hard to find. > > > >Regards, >Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jack Ivey Subject: RE: L4 fedback? Date: Thu, 8 Jan 1998 14:01:54 -0500 I'm surprised that coil resistance is a fundamental limitation. Couldn't you use a current source to feed it? Jack Ivey ivey@.......... > > > >I tried to use the L4 with feedback several years ago, using the VRDT >transducer (the LVDT won't work because the mass rotates slightly as it >moves with the multiple circular leaf-spring suspension.) THe problem >I had was that all my L4s have 5500 ohm coils, which is way too much >resistance for the feedback coil: the response becomes an oscillator, >even using half the coil. Mark Products has made low resistance coils, >but they are hard to find. > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: L4 fedback? Date: Thu, 8 Jan 1998 15:47:15 -0600 (CST) Roger, Jack, & co. In most geophones the coil moves, not the magnet. In the 50's there were a lot of moing-magnet seismometers, including the impressive Johnson-Matheson with a 20? kg mass. Unfortunately, as the sensitivities were cranked up, the moving magnets were found to be moving around because of geomagnetic storms and local distrubances, like cars moving by. So with a moving coil, it is also the effective mass.In most small phones (and the L4-C) the signal is coupled out through the suspensions at each end. Also, the windings are split and wound in opposite directions to cancel any externally induced voltages (they are also at opposite ends of the magnet); the coils are usually wound within brass cylinders and impregnated with epoxy, ie not even repairable. Regarding the resistance of the feedback or force coil in a triple feedback broadband configuration: the object isn't just to get a current to flow through the coil. The current is the summation of three characteristic currents, each producing a different result (proportional, differential, and integral functions of the displacement voltage) that result in an acceleration of the mass due to these currents. In the transfer function, the force coil resistance is a coefficient of the fourth-order term; if it is at all large, the term "blows up". You can see this in the transfer function available in the figures, etc, section at: http://www.eas.slu.edu/People/STMorrissey/index.html Also, in the report in the "seismometer" page, there is a table of parameters of known VBB seismometers, which shows the coil resistances used. And believe me, if the German, Swiss, and British manufacturers of VBB sensors could make high resistances work, we would see it. Regards, Sean-THomas St. Louis Univ. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Marnie Gannon Subject: Live Internet Seismic Server Date: Thu, 08 Jan 1998 14:50:42 -0700 Hey Guys, Forgive me if I already sent this link, http://aslwww.usgs.gov/Seismic_Data/liss.htm/ but wanted to be sure you saw it..online seismograms from stations around the world.. Also a very good link page..http://www.cco.caltech.edu/~meltzner/seismolinks.html which includes the new address for KNBC seismogram Marnie > > Live Internet Seismic Server > > The Live Internet Seismic Server (LISS) allows mulitple users to > receive near-real-time seismic data in a relatively passive way. > Specific data requests are not necessary, nor are individual dial-up > or telnet sessions to seismic stations. Once the software is running > on the host machine and connected to the LISS and desired port, SEED > binary data files are converted to ASCII and may be stored in a > rotating buffer, for example, enabling the user to access live and > recent data at will. > > [Image] Connecting to the LISS > > [Image] Telemetry status > > [Image] Map of telemetry stations and recent earthquakes > [Image]Live data - Helicorder Plots - Updated every 30 > minutes[Image] > > [Image] Preceding two hours of data from all stations > > > > [Image] > > Return to Seismic Data Page > > This page is URL: > Maintained by: webmaster@............... > Last modified on December 3, 1997 (gws) http://aslwww.cr.usgs.gov/Seismic_Data/liss.htm _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: shammon1@............. Subject: [Fwd: time url] Date: Thu, 08 Jan 1998 20:25:36 -0800 This is the URL for the WEB time to set a PC clock via the NBS WEB site. http://www.bldrdoc.gov/timefreq/javaclck.htm From: wb6nvo@............. (Jim Skinner) Subject: BSSA back issues availability Date: Thu, 8 Jan 1998 21:41:46 -0700 (MST) - To all - I have noticed the traffic for the last few days concerning papers/articles published in the Bulletins of the Seismological Society of America. They are currently clearing out a lot of "back issues" that they have extra copies of. The latest BSSA issues discussed in this forum were the 4.5 Hz filter scheme in BSSA , vol. 79, No. 4 , Oct 1989 and "The Leaf- Spring Seismometers: Design and Performance" BSSA , vol. 72, No. 6 , Dec 1982 (this vol is a 2 vol. set; the article is in "6A"). I talked with Kathy at the SSA today and BOTH volumns are still available.....Price I was quoted was $16.50 for both (shipping is included). If anyone is interested call Kathy @ (510) 525-5474 or send her a check (payable to: Seismological Society of America) Seismological Society of America 201 Plaza Professional Building El Cerrito , Ca. 94530-4003 They can take a credit card providing they have a signature. By the way....membership is only $100 per year ($110 outside U.S.) and is worth many times that for the periodicals alone (BSSA and SRL bulletins). I highly recommend membership in this Org. Congrats to Sean-Thomas Morrissey and Charlie Watson for joining (was published in the SSA , BOD meeting minutes in the SRL). - Jim Skinner - Tucson, Ariz. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: Trading Post? Date: Thu, 08 Jan 1998 21:06:56 -0800 My .02 cents... I like the idea... I think this list and a Web page could work out OK. People could make their announcement using this list (I don't think another list just for this is warranted) and a web page could be used to archive the unsold/untraded equipment. I have no problem hosting the web page BUT someone else will have too manage it. I have enough things on my plate... I think we should limit the equipment to seismic monitoring equip. (sensor etc), computer equip., electronic equip. (test equip. parts etc), and EQ safety equip, and maybe others... As I write this Jim Skinner sent out an excellent message about past issue of Bulletins of the Seismological Society of America. This type of message could also be archived on the PSN Trading Post Web page. So if we are going too do this we are first going to need a volunteer to keep the web page up to date. For the first go around I think we should email the info directly to the person who will manage the page. This will cut down on the number of initial post directly to this list. After the web page gets created, and as new items become available, they could be posted to this list and the email messages can be archived on the web page until the equipment gets sold or traded. Larry Cochrane Redwood City, PSN At 08:19 PM 1/4/98 -0700, you wrote: >Hi everyone, > >This is tentative in thought...Is anyone interested in trading >whatever for whatever?? I know for myself... I have a >surplus of old stuff I'll likely never get around to using. > >Expect there is afew out there in the same surplus condition, >who would treasure someone else's endless storage goodies. > >This avocation cost can be considerable over a period of >time and a swap may bring a faster and cheaper solution >than commercial approaches. Guess it would be fun too. > >I'am sure that an endless email approach is not desired over >the PSN machine. Perhaps, for those interested they >could privately communicate outside PSN per their own >individual email. It should be possible to make it a swap >only....no cash involved....except for postage costs. > >Anyway....being as this is just a thought...what do you >think? Rules? Limitations? Gone Fishing in this PSN >pond.........?? > >Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Al Allworth" Subject: Re: [Fwd: time url] Date: Thu, 8 Jan 1998 23:42:33 -0800 -----Original Message----- From: shammon1@............. To: psn-l@............. Date: Thursday, January 08, 1998 7:25 PM Subject: [Fwd: time url] >This is the URL for the WEB time to set a PC clock via the >NBS WEB site. What happened to the URL? My reader didn't show it. I would be interested in getting this URL. Al Allworth allworth@.............. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: TMichel917 Subject: 4.5hz equalizer Date: Fri, 9 Jan 1998 10:31:59 EST There=B4s another way to extend the frequency range of a geophone, develo= ped 15=0Ayears ago by Lippmann. This method is based on an overdamping of= the geophone=0A(similar to the method used in feedback seismometers - it= =B4s based on an=0Aflattening of the response curve by increasing the dam= ping=0Awith an electronic feedback network.).=0AAs a geophone - especiall= y the cheap ones for prospecting work - has only one=0Acoil, the damping = can only be increased by lowering the damping resistor.=0AUnfortunately t= he damping of a shorted geophone isn=B4t high enough - and the=0Aoutput v= oltage is zero. The solution is to replace the damping resistor by a=0ANI= C (negative impedance converter). A NIC is an OP-AMP-circuitry which=0Asi= mulates a negative resistance. With an appropriate negative resistance th= e=0Aoutput of the geophone in the interesting area is no longer proporti= onal to=0Aground velocity above the natural frequency and proportional to= the derivative=0Aof the ground acceleration below it, but proportional t= o ground acceleration=0Aaround the area of the former natural frequeny. T= o get an output proportional=0Ato ground velocity, the output of the NIC = has to be integrated only once by an=0Aelectronic integrator. This method= has some advantages over the method with an=0Ainverse linearisation netw= ork:=0A=0A1. Better linearity because of the smaller displacement of the = internal mass.=0A=0A2. Better Signal-to-noise-ratio because only a one-st= age integrator is used=0Aand lower amplification=0Ais needed and therefor= e a better dynamic range.=0A=0AIt also has advantages over seismometers w= ith a lower natural frequency:=0A=0A1. Robust and unsensitive against har= sh handling.=0A=0A2. Unsensitive against improper leveling.=0A=0AThis met= hod is patented and used by lennartz electronic=0A(http://www.hway.net/le= nnartz), Germany, in their LE-xD/x product line. Their=0Alatest version i= s the LE-3D/20s, a triaxial seismometer with a corner period=0Aof 20 s, w= hich uses 1 Hz geophones. The first model, the LE-3D, is a 1 Hz=0Awhich u= ses cheap 4.5 Hz prospecting geophones.=0A=0ARegards,=0A=0ATorsten=0Ators= ten@............ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Doug Crice Subject: Lennartz geophone Date: Fri, 09 Jan 1998 08:45:27 -0800 Torsten: Fascinating stuff about the Lennartz geophone compensation. Unfortunately, the link seems to be obsolete and I couldn't find a new one on the search engines. Also couldn't find any reference to Lennartz geophone on the IBM patent search home page. Can you provide us with a contact point or new URL? Doug Crice _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: shammon1@............. Subject: Re: [Fwd: time url] Date: Fri, 09 Jan 1998 10:23:25 -0800 http://www.bldrdoc.gov/timefreq/javaclck.htm Here is is again. URL to NBS time Regards, Steve Al Allworth wrote: > > -----Original Message----- > From: shammon1@............. > To: psn-l@............. > Date: Thursday, January 08, 1998 7:25 PM > Subject: [Fwd: time url] > > >This is the URL for the WEB time to set a PC clock via the > >NBS WEB site. > > What happened to the URL? My reader didn't show it. I would be interested > in getting this URL. > > Al Allworth > allworth@.............. > > _____________________________________________________________________ > > 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: Karl Cunningham Subject: Re: 4.5hz equalizer Date: Fri, 09 Jan 1998 09:41:10 -0800 At 10:31 AM 1/9/98 EST, Torsten wrote: >The solution is to replace the damping resistor by a > NIC (negative impedance converter). A NIC is an OP-AMP-circuitry which > simulates a negative resistance. Torsten & the gang -- I experimented with this approach while working on my horizontal FB unit. It worked VERY well, with a period in excess of 1 HOUR! (The natural period of the Lehman-style mechanical system it was mounted on was about 15 seconds) The only problem was that the noise and stability requirements of the op-amp and resistors were quite severe to get this kind of long-period performance, and the change in resistance of the coil with temperature needed to be compensated for. I'm sure that with a good chopper-stabilized op-amp and good resistors, one could make it work for shorter periods with no problem. The design is very simple, since it uses the same coil/magnet for both the velocity transducer and the feedback, and electronics amounts to only an op-amp and a half-dozen resistors, then the integrator stage to get velocity. I think that one could make an ok horizontal seismometer by attaching a mass to a loudspeaker cone and connecting it to the NIC electronic circuit. Air currents would be a problem using a speaker, but it makes a very simple arrangement. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: TMichel917 Subject: Re: Lennartz geophone Date: Fri, 9 Jan 1998 13:57:18 EST Hi Doug,=0A=0Aunfortunately the URL of lennartz electronic is down since = some days or weeks=0Aand I don=B4t know another. Maybe you can get infor= mation about their email-=0Aaddress: lennartz@.................. patent i= s a german one and its number is DE 33 07 575 C2. This is nearly=0Athe on= ly information source about the circuitry, and it doesn=B4t include any= =0Ainformation on how to get the circuitry really work.=0A=0AIf you have = special questions about it I will try to help you.=0A=0ARegards=0A=0ATors= ten=0A _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ken Navarre Subject: Problems with USGS finger server... Date: Fri, 9 Jan 1998 16:18:44 -0800 (PST) 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) From: wizard@......... (Rick Jerome) Subject: USGS Server Date: Fri, 09 Jan 1998 16:30:09 -0800 Yes it has been SLOW when it does work. Noticed it about noon PST yesterday. ------------------------- Michael D wizard@......... N6EGQ Tuolumne, CA ------------------------- "With our ears may we hear what is good." Mundaka _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: J-M, etc. Date: Fri, 9 Jan 1998 19:34:30 -0600 (CST) Bob, The J-M seis was a workhorse of the AFOSR programs, like at TFO. We also had a bunch of them in the Aleutians. I once told the students from CIRES (univ of colo) that they could have one if they could find it. They chased the cable for miles in the tundra; I failed to tell them that it was buried in an oil drum about 4 meters deep and weighed about 150 lbs; the thick steel case provided good magnetic shielding. Our main noise problem there was the wind. Being students, they DID recover the seismometer. I haven't looked at the Benioff question. I would be inclined to use the all-parallel configuration and directly measure the constant with a small mass and a VRDT as a null indicator. Because of the mutual inductances, I'm not sure how accurate a result can be obtained by using series/parallel calculations. Several years ago, I also looked at the S-13 as a possible feedback candidate, but all of mine have high Z coils. We are currently using sets of them as part of the Nuclear Non-Proliferation Test Ban Treaty verification effort. They are co-sited at our broadband stations, and equipped with high gain amplifiers and 24-bit digitizers. Someday I will put some photos of the station in the cavern (CCM) on the web page. I have some "extra" 24-bit channels there, and I hope to use one of them to directly compare the STM-8 with the STS-1s; the channels are currently being used for the microbarometers. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: L4 Seismometers Date: Fri, 9 Jan 1998 20:03:24 -0600 (CST) Al, Nice find of the L4-C seismometers. Mark Products is currently getting $1100 for new ones. Some of your questions: (I have data sheets on them if you can send me a FAX number or SASE). The L4-C is a 1hz sensor, the L4-A is 2 hz (rare) The 23.9 Kdyne/A is the calibration coil constant. The 500 ohm coil has an output of 83 v/m/sec, and takes a shunt resistance of 810 ohms for critical damping. Often this damping resistance is installed at the underside of the connector at the factory. I usually also install 100 ohms in series with the calibration coil to protect it from excessive current. Dismanteling them runs the risk of ruining them. There are stacks of etched leaf-spring suspensions and spacers. The case is opened at the top by pulling the roll pins, or by slitting the case above them and removing the cover; new holes are drilled to replace them. Open the unit inverted, as this clamps the mass. there is one screw at the bottom insulator that holds the whole thing together. If you re-arrange the suspension elements, you probably won't get 1hz again; often it won't even lift the mass; Mark Prod. makes a secret as to how they get the mass suspended with a To of 1 second. Also, the coils are potted in the brass cylinders that make up the mass. regards, Sean-Thomas BTW: some of you are mailing html stuff that is unreadable to most mail readers. I use the old-fashioned UNIX "Mail" that was invented before html. Listing a URL is more useful. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: VBBsensor Date: Fri, 09 Jan 1998 22:14:20 -0800 Sean Thomas I got MCAD working. My 1 sec, .5 kg, 6" vertical sensor seems to have a low frequency knee at 10 sec or so. I have tried to vary the mass, resistors and feedback cap trying to lower the frequency of the knee. The velocity output is more sensitive to certain component values and not so sensitive to others. I found increasing the feedback cap size to do the most good.If I can increase the mechanical free period to 1.5 sec it will help. Any suggestions? Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: China quake, bad news Date: Sat, 10 Jan 1998 09:15:47 -0700 Did you hear that over 47 people were killed from the M5.8 quake in China. *sigh* -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: L4 Seismometers Date: Sat, 10 Jan 1998 11:21:56 -0600 (CST) Ken and co: Ken, One of the wildcards for L4 seises IS the connector: it can be a 6-pin circular pattern, a 6-pin T pattern, a 10-pin full pattern, or a 4-pin square. It is also easily changed because it is a common "06" (I think) MS-type Bendix or Amphenol shell size, (available from Newark, or often electronic surplus) and the connections from the inside wiring and case ground are soldered directly to the back. (If you change it, be sure to add some ohms to the calibration circuit so it can't be burned out by a battery; I had a technician once burn out a bunch of them with a wrong setup, while he "proved" that all of them were open. BTW: a common problem withthe L4 that results from rough handling is a very short mechanical period that results when one of the diaphram leaf springs inverts. It can usually be remedied by a firm blow with the base of the palm of the hand to the side of the case. For handling, the seis should be kept upside down and the short jumper installed across the output pins to damp any movement of the mass. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: VBBsensor Date: Sat, 10 Jan 1998 11:35:18 -0600 (CST) Barry, It sounds like you are getting there. BTW, we usually refer to the changes in slope of the response curve as "corners" ("low frequency corner") even though they look like knees. I use MATHCAD to run an iteration or a sweep of the important values to see what they do. You didn't mention what integrator time constant TI you were using. Usually the effective period comes out somewhere near TI, although you can get a 40-second response with a 20-second integrator. Increasing C does raise the overall output, but rounds out the response away from the desired flat velocity response. If you want me to double check your figures, I need all the values (M, To, Gn, Rn, C, Rp, TI, and RI) you are using. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: VBBsensor Date: Fri, 09 Jan 1998 23:48:22 -0800 Sean Thomas Here's what I started with and what I thought was an improvement Start Current M 0.457kg 0.6 T0 1 sec 1.5 GN 12.653 12.653 Radio Shack speaker RN ? ? C 24e-6 60e-6 RP 5.61e5 1.5e6 TI 80.4 80.4 RI 1.07e5 1.07e5 r 234,000 234,000 Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roger Baker Subject: Seismometers Date: Sat, 10 Jan 1998 14:20:58 -0600 Well Sean-Thomas, It has indeed been a delight to read your posts on PSN. What PSN has lacked is someone truly knowledgeable about seismic design. I=92m a hard core instrument freak and inventor myself, and am quite interested in this topic right now. But there is no substitute for someon= e like yourself, conversant with the decades of engineering experience that have been incorporated into commercial products. Incidently I would describe your vertical as a straight-forward hack closely along Streckeis= en (sic-is that the name of that thing?) lines. Let me describe my current understanding of some of the principles of seismic design and then maybe you can correct any misimpressions. Apparently, one general principle with verticals is to be certain the mas= s moves along only one axis-has one degree of freedom. This is the point of the crossed hinge, which effectively defines a pivot axis, as a knife edg= e would do. But there are other ways to do the job. If we suspend a weight from a hacksaw blade clamped in a vise so as to be= nd the top of the blade over horizontal and then suspend a four ounce lead weight from a link of copper wire from the hole in the end of the blade, = we get an oscillator with a period of a second and the oscillations may take twenty minutes to die down-- a very high Q system with a long distance of vertical travel.=20 Easy to set up for one thing--I did it just last night and recorded the results with a DATAQ, because it was simple to rig up and I was curious. For detection I use a phototransistor in close proximity to an LED and chopped by an aluminum flag glued on the bottom of the weight. Such a detector is DC and has nanometer resolution-handy technique.=20 The thing is supersensitive to 1 sec jolts as you would imagine and prett= y useless as a seismometer because of the high Q and lack of damping in the described form. If I should turn this into a useful seismometer, my first step would be to kill the unwanted degrees of freedom by stretching two very fine horizontal nylon filaments at right angles and attach then to t= he lead weight to restrict its travel to the vertical axis and induce heavy damping with any sideways modes of mass vibration. I see some on the char= t. In my mind, the most innovative aspect of your instrument is the use of a loudspeaker coil to induce feedback force. Generally speaking, you are miles ahead in the game if you can borrow some well- engineered, mass produced technology to solve your problems. And a loudspeaker is a great fast high power force actuator so far as cost and mechanical characteristics are concerned ( I have used loudspeakers to build little micropumps, but for some reason, their use in this application had not occured to me). The end result should be to impart as least as much force to the mass as the ground shocks deliver null it. I think you say the force should actually be equal to the full weight of the mass. So you should be able t= o apply four ounces of force at least momentarily with your speaker coil to= a four ounce mass like my fishing weight. In other words, small speaker, small weight. And there is some proportion that fits best as you scale the instrument size up or down.=20 Its dangerous to challege an expert such as yourself, but I do not believ= e I agree with your rule of thumb that the product of the mass in kilograms and period should be at least one. In other words, you should typically t= ry to have one kilogram mass and one second period.=20 I am strongly oriented toward trying to reduce the size of the instrument. The constraints of temperature drift and barometric bouyancy encourage small designs. I like to use an electrical feedback thermostatted enclosu= re for similar instruments and its easy to build small hermetic enclosures from gallon jugs I think Black (?) did a paper on a quartz torsion fiber and horizontal beam gravimeter in the 1960=92s. It was an excessively gold-plated force feedback design, but the device was very small and sensitive to seismic shocks. My understanding from reading this and Melton=92s stuff is that t= he theoretical limit on size is the brownian movement of the mass, but that = in reality the limit is much more likely to be too much energy loss from air damping, which is less with larger masses. Melton suggested that the prop= er bottom limit was 100 grams or so because of the difficulty of pulling and maintaining a high vacuum on plastic coated wire!=20 So my conclusion is that tradition has dictated that seismometers are larger than they probably need to be -- and they could be somewhat or maybe a lot smaller without sacrificing much sensitivity. This conclusion is somewhat in line with the conclusion that long period geophones can be filtered to detect teleseismic events, although perhaps with some loss in sensitivity. Has anyone ever filled a geophone with helium or pulled a vacuum on one to cut gas damping losses? I=92m weak on feedback theory, but my reading of your force feedback appr= oach is that you insert a sort of filter between sensor and speaker coil such that it passes three sources of current; first a straight-through signal, second a low pass or integrated response component, and third a different= al response component through a capacitor. I assume this is right? That mean= s if you could get a big enough choke coil as an integrator, you could have just it, a properly sized resistor and a capacitor in parallel in the loo= p and get equivalent results? This seems to me sort of equivalent to a not= ch filter with adjustable parameters. My own quasi-Luddite approach would be to put three potentiometers in series with each path and then twiddle the three pots until the step response showed the best damping and overall best results. I posted the details of one such force feedback circuit, that works in some cases, recently. I=92m a seat of the pants analog designer, weak on the mathemat= ical side--I=92ve never done a Bode plot to compute critical stability criteri= a, but I have a vague understanding of what is going on. Enough for now. If I=92m way off base in any of my notions, I=92d like to= know. You can repost any of my comments or your possible reply as you wish and = as you think appropriate. PS, did you happen so see my super cheap and simple microbariograph desig= n that I posted a few months back? I notice from your web page that you've worked with the commercial versions. --Yours, Roger Baker; Austin, Texas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Francesco Subject: MAJOR QUAKE IN CENTRAL MEDITERRANEAN SEA Date: Sat, 10 Jan 1998 21:55:05 +0100 Hi guys, Date: 090198 19.21 UTC Preliminary Locate and Mag: 1000 km se from Ancona-Italy: SOUTHERN GREECE - Mb: =>5.5 Registered by all stations of ITALIAN SEISMIC INTEGRATED NETWORK Greetings to all Francesco FRANCESCO NUCERA OSIMO - Ancona - ITALY Lat. 43 29" E - Long. 13 29" E _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Trading Post & Larry C's web page donation Date: Sat, 10 Jan 1998 13:54:36 -0700 Hi everyone, Being as I initiated the trading post thought; I feel compelled to respond to Larry Cochranes generious web page offering response. To lay the facts on the line...however, I have as much web page experience as frogs hair is obvious....zero zilch to be exact. Moreover, I don't have the faintest idea what would be involved...unless I delve into this Netscape program which may or may not be adequate?? The manual I have jumps like a frog in subject change. I think they presume everyone is a computer geek already :>) Hey...I can press the wrong button REAL well! I feel strongly about the equipment issue as being the most frustrating parts of this avocation. This is...one of the rarest hobbys there is, and the commercial prices reflect it. Even home brew (all kinds), requires the mental approach of an engineer (all kinds), and compensating green (much) to evolve something that works, let alone work good, or best of all to be reliable & good for a long time (rare). An individual has to be a scavenger to pick the brains and castoffs of others to have some success, let alone what they can learn along the way. Nothing wrong with this, we all do it, and sometimes some of us,.... get the thrill of being asked for our expertise. I can remember my own start (too many years ago), as being somewhat of a....collecting the hairs of a frog into something substantial....mostly the evaporation of fried electronics....due to the lack of funds for more newer components (I hate old capacitors that bang). Hence, .....there is a world of people interested in this, but money controls and limits and often forces an end to their interests. But.......if people have a web page to check...there maybe a piece that helps...may be not....BUT, maybe it offers a glimmer of hope for their precious interests with the page just being there. Pieces & parts seem to be the rule of most of us...one here and one there...mostly scarce or too high priced, BUT MAYBE THERE ON THE WEB PAGE. I carry on don't I? Anyway...being things as they are and with my limitations, unless someone has more computer experience with web page stuff...I will have to decline any kind of consideration as a volunteer...unless you all want to wait a long time and wait for me to gain (any) web page knowledge. GPF's seem to love me...(this is normal?) So....for now...does anybody have the experience..and is willing to do this for the rest of us? Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Mike Lozano Subject: Re: Trading Post & Larry C's web page donation Date: Fri, 09 Jan 1998 22:33:12 -0600 Hi Meredith & the bunch, Like you, I don't have a much experience with maintaining a Web page, much less a Web site, but I'm willing to learn. I have PageMill (which I'm trying to learn) & PhotoShop 4 (which I use regularly). Since I cast the first stones with a vacuum pump and packet telemetry system which I haven't had any response to, although I'd love to trade them for almost any kind of seismo equipment, I'm going to open my mouth to volunteer to help with a trade page. I someone has the room to host a page, I'll contribute updating and artworking in return for all the stuff I've learned about this fascinating hobby by just 'reading the mail'. How 'bout it? Mike Lozano. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Karl Cunningham & NIC circuit Date: Sat, 10 Jan 1998 15:14:41 -0700 Karl, In your 1/9/98 msg re: 4.5hz equalizer about a NIC op amp, you had a VERY interesting mention of a previous circuit you had tried out and thought it may have some merit for a seismo FB circuit. I'am very interested in learning or getting more info on that specific circuit. It sounds just too good to pass by! It maybe difficult temp wise, but with the few parts mentioned, it could be much more reliable over time because of that. Any availability of more info? Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Caruso Subject: Re: China quake, bad news Date: Sat, 10 Jan 1998 19:11:36 -0500 (EST) It is a terrible tragedy for those involved. The brighter side is that it was predicted according to the wire service several days ago, but only with a large window into the future. I read the news after getting online at 730am est and the wire report said it happenned at 0323gmt That would have made it an hour later then when I read the report? STEPHEN CARUSO CET KB8UGH "Coincidence is a shortsighted mental delusion" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Seisguy Subject: Fwd: Quakes Rattle Sicilian Volcano Date: Sat, 10 Jan 1998 21:42:36 EST For those of you interested...... Mike 
Quakes Rattle Sicilian Volcano


.c The Associated
Press


 CATANIA, Sicily (AP) - A series of earthquakes rattling Mount Etna raised
concerns Saturday that the volcano in eastern Sicily might erupt.

``Etna is experiencing a serious enough seismic crisis,'' said vulcanologist
and Civil Defense official Franco Barberi. ``Now we're looking to see if it's
moving toward a true eruption.''

Etna last had a major eruption six years ago. Farm villages stud the volcano's
slopes, and skiers in winter enjoy the mountain snow.

Of the several quakes that began rattling Etna's slopes on Friday evening, the
strongest happened Saturday morning, reaching a preliminary magnitude of 3.8.
A quake of magnitude 2.5 to 3 is the smallest generally felt by people.

No plans to evacuate were announced.

AP-NY-01-10-98 2118EST


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


 

To edit your profile, go to keyword NewsProfiles.
For all of today's news, go to keyword News.
From: barry lotz Subject: .WAV files Date: Sat, 10 Jan 1998 09:19:34 -0800 Hi all Does anyone know of a DOS or WIN3.1 program that will perform an FFT on a sound (.WAV) file? If not how about one that will save the file as ascii numbers (.dat or .txt) file? Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Re: .WAV files Date: Sat, 10 Jan 1998 20:33:48 -0800 At 09:19 AM 1/10/98 -0800, you wrote: >Hi all > Does anyone know of a DOS or WIN3.1 program that will perform an FFT >on a sound (.WAV) file? If not how about one that will save the file as >ascii numbers (.dat or .txt) file? Santis does. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roger Baker Subject: Mis-posting happens! Date: Sat, 10 Jan 1998 23:38:11 -0600 Whoops, Sorry Folks! I didn't mean to post my comments directed to Sean-Thomas to everyone else on this list, as may have been apparent. But no harm done and it may have been of some technical interest to others. My apology. --Yours, Roger baker _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: kathy mortensen Subject: Re: Mis-posting happens! Date: Sat, 10 Jan 1998 22:08:12 -0700 Roger Baker wrote: > > Whoops, > Sorry Folks! I didn't mean to post my comments directed to > Sean-Thomas to everyone else on this list, as may have been apparent. But > no harm done and it may have been of some technical interest to others. My > apology. > > --Yours, Roger > baker > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L No apology needed here, I hope he comments to the PSN as I am very interested in his projects. It's refreshing to find people willing to share their experiences without a price tag. also, I'm glad to see others using a DATAQ!! While I'm at it, my detector and DATAQ logger recorded the Guatemala (6.4) quake at 00:27:01 PST add approx. 5 sec. for a slow computer clock. SKM My loc. Lat. 38.828 N Lon. 120.978 W _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roseberry Subject: Re: .WAV files Date: Sun, 11 Jan 1998 00:14:57 -0600 Barry: Try the following URL: http://www-pw.physics.uiowa.edu/mcgreevy/ This page is by a researcher (Stephen P. McGreevy) who records audio-band natural rf, then "listens" to them. Near the bottom of the above referenced page, you will find a link for downloading something called "GRAM23.ZIP"; an explanatory paragraph is reproduced below: GRAM23.ZIP, 33333 bytes You can download SPECTROGRAM 2.3, a freeware Spectrogram program written by R. S. Horne. This spectrogram program plots frequency- versus-time of digital audio recordings. A sound card is required, as this program will not play WAV files using the Windows 3.1x PC-Speaker Driver (as will Sound Recorder). Contains two files: GRAM23.EXE and README.TXT. Lets you save the spectrogram display to a *.bmp file for viewing with Paint Brush. You can also Paste screen prints of the maximized Spectrogram 2.3 window into Word 6.0 or other graphics capable word-processors. Version 2.3 has been improved over version 2.2, allowing for unlimited-length files and also improved bitmap image creation. I used this program about a year ago and found it quite adequate for my needs; it has a very nice user interface, as well. It may serve your needs as well. As they say: you mileage may vary ... Regards, Michael J. Roseberry Fort Worth, Texas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: WAV FFT Date: Sat, 10 Jan 1998 12:04:07 -0800 Michael,Rick&Norman Thanks for your help. I can see many productive hours making use of SANTIS & GRAM32 and WAV files. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: W6JRF Subject: Re: Mis-posting happens! Date: Sun, 11 Jan 1998 04:32:43 EST I concur with mortskm, no apology needed here either. I found your posting so interesting, I printed it out for my paper archive. While I don't have any equipment as of yet, I know all the info I can gather now will save me time, trouble and that all important factor, MONEY! when I finally do get going on this fascinating pursuit. Keep the info coming. Thanks. Bob (W6JRF @ AOL.COM) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Francesco Subject: Re: Fwd: Quakes Rattle Sicilian Volcano Date: Sun, 11 Jan 1998 11:39:41 +0100 The swarm is still in action. It have been registered around 100 events with MG<= 3.0 The last eruption of the Etna Volcano has happened 6 years, with serious damages. The actual crisis is initiate in the month of December with repeated harmonic shivers and some shake among 3.3/ 4.0 Mg. These elements do retain that an eruption is possible and liable, but of sure there are not such elements that could do retain that a big eruption will be audited. The recent epicenter has located at 3 km of depth in the zone of north/ west of the mountain, then not in the more dangerous zone that is the crater of north/east. The events have followed from the Institute of Vulcanologia of Catania, from the Observatory of Acireale and from our station of Siracusa of ITALIAN SEISMIC SPERIMENTAL NETWORK For more details, contact us. Greetings At 21.42 10/01/98 EST, you wrote: >For those of you interested...... > >Mike >From: AOL News >Return-path: >Subject: Quakes Rattle Sicilian Volcano >Date: Sat, 10 Jan 1998 21:22:21 EST >Organization: AOL (http://www.aol.com) >Content-type: text/plain; charset=US-ASCII >Content-transfer-encoding: 7bit > >
Quakes Rattle Sicilian Volcano
>
>
.c The Associated
>Press

>
> CATANIA, Sicily (AP) - A series of earthquakes rattling Mount Etna raised
>concerns Saturday that the volcano in eastern Sicily might erupt.
>
>``Etna is experiencing a serious enough seismic crisis,'' said vulcanologist
>and Civil Defense official Franco Barberi. ``Now we're looking to see if it's
>moving toward a true eruption.''
>
>Etna last had a major eruption six years ago. Farm villages stud the
volcano's
>slopes, and skiers in winter enjoy the mountain snow.
>
>Of the several quakes that began rattling Etna's slopes on Friday evening,
the
>strongest happened Saturday morning, reaching a preliminary magnitude of 3.8.
>A quake of magnitude 2.5 to 3 is the smallest generally felt by people.
>
>No plans to evacuate were announced.
>
>AP-NY-01-10-98 2118EST
>
>
 Copyright 1997 The Associated
>Press.  The information  contained in the AP news report may not be
published,
>broadcast, rewritten or otherwise distributed without  prior written
authority
>of The Associated Press. 

>
> 
>
>To edit your profile, go to keyword HREF="aol://1722:NewsProfiles">NewsProfiles.
>For all of today's news, go to keyword HREF="aol://1722:News">News.
> FRANCESCO NUCERA OSIMO - Ancona - ITALY Lat. 43 29" E - Long. 13 29" E _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: wizard@......... (Rick Jerome) Subject: Re: .WAV files Date: Sun, 11 Jan 1998 07:48:03 -0800 At 12:14 AM 1/11/98 -0600, you wrote: >Barry: > >Try the following URL: http://www-pw.physics.uiowa.edu/mcgreevy/ > I have been using Gram32 to watch the Seismo information transmitted on VHF from the USGS and DWR. It works quite well for non-critical viewing. Just run it when I'm in the shop. The filtering features allow you to view a single channel. Lots of nice features. I highly recommend it. DATAQ software will also view wave files. You just need to input the correct information in the import program. You will see some incorrect data at the beginning of the file. That data is the header information. You can select a different portion of the wave form for FFT. It also does inverse FFT after filtering. I downloaded it from DATAQ. ------------------------- Michael D wizard@......... N6EGQ Tuolumne, CA ------------------------- "With our ears may we hear what is good." Mundaka _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Bob Thomasson <102073.3346@..............> Subject: Re: .WAV files Date: Sun, 11 Jan 1998 10:53:33 -0500 There is also a fairly elaborate 30 day free trial FFT program at www.telebyte.com/pioneer. It looks to be very interesting. I downloaded it, but the 30 clock expir= ed before I got around to really experimenting much with it. Also, don't know the cost if you want to keep it after 30 days - I think it's $300+ Regards, Bob _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: .WAV files Date: Sat, 10 Jan 1998 22:07:54 -0800 Rick I tried Gram32.I like it. It's small and I have been looking for a program that produces a spectrogram. Do you or anyone else know what the PCM or WAV format is? I always wanted to review recorded quakes this way (without writing the program myself). I would like to adapt some of my recorded events for spectrogram viewing. Barry Rick Jerome wrote: > > At 12:14 AM 1/11/98 -0600, you wrote: > >Barry: > > > >Try the following URL: http://www-pw.physics.uiowa.edu/mcgreevy/ > > > I have been using Gram32 to watch the Seismo information transmitted on VHF > from the USGS and DWR. It works quite well for non-critical viewing. Just > run it when I'm in the shop. The filtering features allow you to view a > single channel. Lots of nice features. I highly recommend it. > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: .WAV files Date: Sun, 11 Jan 1998 12:07:11 -0600 barry lotz wrote: > > Rick > I tried Gram32.I like it. It's small and I have been looking for a > program that produces a spectrogram. Do you or anyone else know what the > PCM or WAV format is? I always wanted to review recorded quakes this way > (without writing the program myself). I would like to adapt some of my > recorded events for spectrogram viewing. > Barry You might want to look at http://www.wotsit.demon.co.uk/ for file formats. I have succesfully input PSN format files into CoolEdit by telling it the file was a raw 16 bit binary file and editing off the header. But sometimes it gets a byte off and doesn't work. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: VBB Seismometers Date: Sun, 11 Jan 1998 15:12:43 -0600 (CST) Roger & co, A few comments on your comments and questions, which seemed to be an inquiry about why I came up with the "STM-8" sensor. Re the reference to the Strecheisen "STS-1" broadband sensor: I wouldn't say that my sensor has any special relation to it, because leaf-spring sensors have been experimented with for years. And feedback concepts have been applied to overcome the non-linearity of many systems, especially gravimeters. The STS-1 ideas have been described in some detail in the journals. With a response to 360 seconds, is the choice of the world for high-gain, broadband sites. But it is VERY expensive. Guralp Systems of England makes a similar line of compact wideband units at about 1/3 the period and price, but still more than a new car. And Strecheisen also makes a clever compact 3-component 100-second unit, the STS-2, that is very useful for most sites, but still cost gt. $10k. ("clever" because it uses three identical sensors tilted at 45 deg. arranged 120 deg, and electronically summed for vertical and two horizontal outputs). I have been following the development of these sensors for years, and have watched the competition force the performance and price up. THe main performance problem is temperature stability and the noise floor. The USGS lab at Albuquerque has sort of "defined" the noise battle by establishing their "NLNM" model in 1993. ("Observations a and Modeling of Seismic Background Noise", by Jon Peterson, USGS open file report 93-322). In a nutshell, they plotted the PSD (Power Spectral Density) of the quietest data from all the broadband sites around the world, and drew a line under it to represent the "inherent" noise of the earth. So all the instrument makers are trying to show that the self-noise of their sensor is less thatn the NLNM. (BTW, the report "featured" my station CCM in the cavern in the Ozarks because of its' quietness AND susceptibility to barometric noise). You can see the shape of the noise models in my noise study figures when I get them scanned to the web page (maybe tomorrow). But my interest has been a concern for the cost and avaliability of broadband data. The basics of the sensor just aren't that complicated. Once I had a good mathematical model of the transfer function (that properly verified the response of the commercial units with what I knew or could surmise of their physical parameters), I started to look at retrofitting existing mechanisms for broadband response. A major success has been running an old WWNSS long-period vertical at 600 seconds for our display seismograph. The problem with most verticals is the coil spring, which rings without damping; the lateral ringing mode actually shortens the spring, raising the mass in the broadband configuration. So we get one-sided bumps when classes change and the students romp down the stairs (the vault is under the stairs). So I started to evaluate leaf-spring configurations like the available clamped arrangements and realized what a headache it was. Then I found that a flexured suspension avoided all the problems of a clamped spring, and made a seismometer out of it last April. I had already found that the open construction of the VRDT allowed lots of forgiveness in the lateral movement of the boom/mass/coil for large mechanisms; it is only sensitive in one axis. And I had been looking at speakers as seismometers, but the stiff compliance of their suspensions (resonance at 30hz) makes a broadband response difficult. So separating the coil from the magnet was the next step, but brought up the problem that the length of the boom controls the arc of the movement of the coil in the magnet gap; with a 12" boom, it is about 3mm, which is actually plenty for a fedback system; it just takes patience to set up. This is the major constraint on the size of this current arrangement; it would be nice it it all would fit inside a pressure-cooker for protection from barometric noise. Pressure contaiment is used for all the commercial units, but only the STS-1 is actually evacuated. Evacuation makes the baseplate a barometer; the STS-1 has a very thick glass plate that has to be vacuum-grouted to the cement pier surface. Generally a pressure tight case is used, such that pressure CHANGES are reduced, and designed so the base does not flex. We have a continuously recording gravimeter with such a case; you have to vent the cover to open it if the barometer has gone up. Regarding intrinsic damping by air in the container: it is a well known parameter called Bo (actually Beta), and is used to calculate the effective damping. Like for the L4-C, Bo is 0.28; if you want critical damping at 0.7, you need to calculate electrical damping (via the shunt resistor) to contribute (0.7 - 0.28) or 0.41. Regarding the size of sensors: the literature is full of articles on the tradeoff of size vs sensitivity vs self noise. Smaller size can fit into a borehole away from surface noise is the self-noise is controlled. A larger mass raises the Q (quality factor) nicely: my 600-second LP has a mass of 11kg and a period of 15 seconds, so it doesn't show much wind noise; its' containment is a box. But the homemade in my basement here shows a bump when there is enough wind to ring the chimes outside. Regarding the feedback system. I must again emphasize that it is NOT an arrangement of filters of any sort. The three feedback paths EACH provide a characteristic force on the mass based on the information (voltage) from the displacement transducer. Where F=m*a, the result is three characteristic accelerations that shape a linear response that is described by the physics of the terms of the transfer function, which defines the voltage output per input of ground acceleration. Multiplying the acceleration response through by omega (Vel = A *s; s = j*omega) gives the flat velocity response as shown in figure 2. If any of the feedback paths dominate or are missing, the response "blows up", "goes ballistic", or whatever, or is unstable and an oscillator. This is also why the contribution of EACH feedback path is a CURRENT that MUST flow through the force coil. Any modification of this current path makes this concept and transfer function void. It is important to note that WITHOUT the feedback, the displacement detector output is just that, and useful for centering the boom; when, and ONLY when, the feedback is connected, it BECOMES the full broadband output. I guess that MY most important point is that there are endless variations on making something to record ground motion. But to have any scientific usefulness, we cannot just fiddle with hardware and electronics until something "looks" right. We need CALIBRATED instruments, with a stable and reproducible response, recording moderate size events in a digital mode such that the data can be retrived or sent to some collection point in a standard format. And to get calibrated data, we must know exactly how the sensor works, and be able to verify it at will (see fig 12; also the new abstract I have submitted for the March SSA meeting). And a sensor with a broadband response will record the quake in the next county as well as the quake in Tibet without the need of multiple instruments (albeit at different sample rates). I assume that the PSN does want to contribute to the scientific data base with more than just phase arrival times: seismology is in great need for full waveforms (esp. 3-component) for ground motion, attenuation, and tomographic studies. As extensive as "professional" networks are, they do not have stations down in (eg) the inhabited valleys of California (where we really DO need ground motion data), or in every 100x100km area of the world to do tomographic studies of the interior of the earth (a method like a CAT scan that uses a single large quake (eg in Tibet) as the signal source and looks at how the earth modifies the waveform over all possible paths to all possible receivers ie. seismographs). A global network of personal and school broadband seismographs would significantly contribute to this. I hope that all this addresses your interests. Regards, Sean-Thomas St. Louis University _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: wizard@......... (Rick Jerome) Subject: Re: .WAV files Date: Sun, 11 Jan 1998 14:07:05 -0800 >You might want to look at http://www.wotsit.demon.co.uk/ for file >formats. > >I have succesfully input PSN format files into CoolEdit by telling it >the file was a raw 16 bit binary file and editing off the header. But >sometimes it gets a byte off and doesn't work. >-- >Jim Hannon Kind of neat to re-sample the quake and listen to it. Like the FFT display and filtering. ------------------------- Michael D wizard@......... N6EGQ Tuolumne, CA ------------------------- "With our ears may we hear what is good." Mundaka _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: .WAV files Date: Sun, 11 Jan 1998 03:47:03 -0800 Yeh I agree! I set the sampling frequency at 1000x the real sampling rate so you can look at real frequencies and hear it also. It is also neat to look at a scanner file for carrier frequencies. I'm looking for USGS stations near me. Barry Rick Jerome wrote: > > >You might want to look at http://www.wotsit.demon.co.uk/ for file > >formats. > > > >I have succesfully input PSN format files into CoolEdit by telling it > >the file was a raw 16 bit binary file and editing off the header. But > >sometimes it gets a byte off and doesn't work. > >-- > >Jim Hannon > > Kind of neat to re-sample the quake and listen to it. Like the FFT display > and filtering. > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Dewayne (n0ssy) & Linda (n0uqf) Hill" Subject: Meteorite Impact in Denver, CO. Date: Sun, 11 Jan 1998 23:06:00 +0000 I heard on the local news that a meteorite impacted in the Denver area last night. Does anyone have any info on this? Regards, Dewayne Hill _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Al Allworth" Subject: STM-8 sensor Date: Sun, 11 Jan 1998 15:16:20 -0800 S-T Morrissey and PSN I have had more time recently to go over the design of the STM-8 and try to understand how it works. I work a little differently than some people in analyzing something like this. I have to understand how it works before I can see the significience of the numbers. Others get the "how it works"part from the numbers. I'll describe how I think it works and see if I am comming close to reality. In some fedback sensors the feedback removes (almost) all motion from the boom and the various output signals are derived from the feedback signal that is the drive to maintain the boom position. It appears that in the STM-8 this is completely different and the whole purpose of the feedback is to interact with the existing parameters ie: natural period, mass, inherant damping, frequency response, etc to produce suitable new parameters to provide the needed frequency response, lower period, damping, and sensitivity for a more useful seismometer. Since the feedback transducer is also a powerful generator, its dynamics interact with the three feedback networks so that they not only modify the effect of the feedback on the transducer but also have a loading effect on the transducer's output as a generator. This is why the signals can't be summed in an op-amp and then applied to a higher resistance feedback coil. Have I come close? In regards to the L4: Is your mailing address in your web page OK to send a SASE for the data sheets on the L4? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: VBB Seismometers Date: Sun, 11 Jan 1998 17:21:49 -0600 S-T Morrissey wrote: > And Strecheisen also makes a clever > compact 3-component 100-second unit, the STS-2, that is very useful > for most sites, but still cost gt. $10k. ("clever" because it uses > three identical sensors tilted at 45 deg. arranged 120 deg, and > electronically summed for vertical and two horizontal outputs). > > Sean-Thomas, This is the type of 3 axis sensor that I have been working on. According to my calculations the angle with respect to horizontal is 54.73 degrees for an orthogonal arrangment. I plan on doing the axis rotation in software from the sampled data. If the three sensor outputs are A, B and C the equations for the vertical and horizontal outputs are Z= .57735A + .57735B + .57735C X= .81644A - .40822B -.40822C Y= 0A + ..70706B - .70706C I think it is neat because you can use the same design for all three sensors. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: STM-8 sensor Date: Sun, 11 Jan 1998 18:29:05 -0600 (CST) AL, The mailing list onthe web page is correct. I also think that your concept of the triple feedback is getting to the point. All the elements interact to produce the output. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: triaxial VBB Date: Sun, 11 Jan 1998 18:33:15 -0600 (CST) Jim, The idea definitely has possibilities for the PSN. We can avoid any question of copying the STS-2 by referring to "The symmetrical triaxial seismometer -- its' design for application to long-period seismometry" , by B.S. Melton and B.M. Kirpatrick, BSSA 60, 1970. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Re: Meteorite Impact in Denver, CO. Date: Sun, 11 Jan 1998 20:34:02 -0700 Am checking...various meteorite web sites...only indefinite chatter in cosmic chat room....something like there May have been one about 12:10 Am m.s.t., boom, softball size....would not rely on this as definite. No other references found. It's amazing the number of web meteorite sites, but they are generally 6 months out of date. No local paper mention, but think that if it hit at that time, the paper would have been in production. Will check paper tommorrow a.m. The chat room also mentioned washington or Colorado, wonderful indefinite babble, mostly selling and buying. All this reminds of the Greenland one....days pass before anything definite shows up. Gee Whiz! I'am as bad as they are....I've been fixated on football games! Dewayne (n0ssy) & Linda (n0uqf) Hill wrote: > I heard on the local news that a meteorite impacted in the Denver area last > night. > Does anyone have any info on this? > > Regards, > Dewayne Hill > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Meteorite Impact in Denver, CO. Date: Sun, 11 Jan 1998 20:15:30 -0700 Speaking of meteorites et al, I received Walter Alverez's new book" T. rex and the Crater of Doom" for Christmas and finally had some time to sit down and read some of it. Humm..compelling! Ah, that passion of geologic discovery gets me every time. -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: W6JRF Subject: Re: .WAV files Date: Mon, 12 Jan 1998 01:01:12 EST Rick, since I don't have any seismo equipment at this time, I am very interested in the frequencies you are using to copy the singals from USGS and DWR. Any chances of you posting them here? Thanks. Bob W6JRF@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Al Allworth" Subject: LA Event Date: Sun, 11 Jan 1998 23:31:54 -0800 Heard something about a 4.0 near Panarama City. Not on USGS yet. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: LA Event Date: Sun, 11 Jan 1998 23:37:49 -0700 M3.2 - 2 mi ssw of Panorama City. Got a couple felt reports already. -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: Trading Post & Larry C's web page donation Date: Mon, 12 Jan 1998 00:14:16 -0800 Meredith and Mike, Don't worry about the actual web page construction, that's the easy part. HTML code is nothing more then some simple text commands. If one or both of you can maintain the page I can come up with a template for you guys to use. All you will need to add is the text describing the equipment and maybe a link to a picture if one is available. Since Mike has a web page maker (I use my text editor for my pages) maybe he should be the main contact / maintainer and Meredith could be backup? I guess the next thing to do is too have people submit there equipment / wish list to Mike so he can create the page. Mike, if this is OK why don't you announce it to the list and when you have a page ready all you need to do is send it to me as an attachment and I will place it on my web server. Regards, Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Walt Williams" Subject: Re: LA Event Date: Mon, 12 Jan 1998 01:53:47 +0000 Hello Charles Watson and All, Around 22:30, 98.01.11, (Canoga Park, California, USA) a short (less than a second) violent jolt was 'felt'. Again, in our house we generally 'hear' a loud bang sound just prior to these earth quake events. Best Regards, Walt Williams, 98.01.12 dfheli@.............. Canoga Park, (LA suburb), California USA =================== ------- Forwarded Message Follows ------- Date: Sun, 11 Jan 1998 23:37:49 -0700 From: watson@................ (Charles Watson) Organization: Advanced Geologic Exploration / Seismo-Watch To: PSN-L Mailing List Subject: Re: LA Event Reply-to: PSN-L Mailing List M3.2 - 2 mi ssw of Panorama City. Got a couple felt reports already. -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Walt Williams" Subject: Audio FFT program uses sound card Date: Mon, 12 Jan 1998 06:50:34 +0000 Hello All, Located on the top of the last page, an interesting Win95 audio frequency FFT program, 'Frequency Analyzer', which uses sound cards can be had: http://www.relisoft.com/freq.html Program which is written by Bartosz Milewski, is distributed with both Win95 binary executable form as well as with C++ source code which can be compiled. MicroSoft VC++ 4.2 can be used to compile the program; a little twiddling is necessary. Program in its present version does not record nor read files, but that feature should be easy to add. Plug a microphone in and observe in 'real-time' both frequency-domain as well as time-domain spectral audio plots. Walt Williams, 98.01.12 dfheli@.............. Canoga Park, (LA suburb), California USA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Seisguy Subject: Re: LA Event Date: Mon, 12 Jan 1998 10:30:03 EST In a message dated 98-01-12 02:41:31 EST, Charles Watson wrote: > M3.2 - 2 mi ssw of Panorama City. > Got a couple felt reports already. > Was felt solidly in Northridge. It was a real fast shake, but short in duration. Scared the dog. Mike O'Bleness Northridge, CA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Francesco Subject: CIO-DAS08/JR A/D & EMON Date: Mon, 12 Jan 1998 17:11:03 +0100 Hi guys, I'm installing CIO-DAS08/JR A/D for one of my sensor. It's need that I know the right A/D I/O address for setting Emon compatible software (downloaded from Bob Hammond ftp-side) or if these is automatically recognized by the programm. I want to know too the best setting of software: sample, noise, buffers ecc.ecc. Thank you very much. Regards Francesco Nucera Osimo - Italy Lat.43.29N Long.13.29E _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Colo. Springs meteorite Date: Mon, 12 Jan 1998 11:00:53 -0700 Hi Group, Apparently there was a meteor which came down near Colorado Springs, Colorado, about 12:15a.m. 1/11/98. Apparently many witnesses varying from there, to as far away as about 100 miles. Some say their may have been an impact with house vibrations, and then multiple explosions heard. Description variations of bright white to big blue as it passed through the atmosphere and clouds. A security camera in Colorado Springs which caught the light of another meteor in 1995, also caught the moving light reflection of this one. Local authorities are involved in the details of this new one, and hopefully their will be some more news in the ensuing days ahead. Sounds like the ideal Steve Spielberg movie plot...huh? You know that all this meteorite talk conjures up my own story.... When I was about 10 years old (give-take ~ years), and was out playing at night in Sterling, Colorado (northeast Colo); there was suddenly a bright flare like object coming down vertically. The object was almost like a military flare it seemed to take forever to reach the ground...uh...maybe 30 seconds. It really lite up the sky with an intense white light...no sound. Well....it took about 2 weeks of people searching before it was found...just inside Nebraska. The specimen is now in the Denver Museum of Natural History. Most meteors usually travel about 40 to 60 miles per second~,....this one must have been alot slower than that. It weighted (from memory) maybe 10 or so pounds. An iron variety. Naturally my excited story was dismissed by my partents...till the next day. The original location was Denver, which is false, but at the time I rechecked my gram for the rough time slot....just in case I slept thru any sonic boom vibration.....nah!....hard to tell from the gram, what with the China & Guatamala stuff cluttering up the record and no time marks. Too bad I don't have any A/D stuff yet, that would really be interesting to see a spike for the time. Colorado Springs is about 60 miles south of my Denver location. Meredith Lamb P.S., big distant quake rattling chart recorder for the last hour or so. Difficult to concentrate on this msg (I'am teasing of course). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: wizard@......... (Rick Jerome) Subject: Re: .WAV files Date: Mon, 12 Jan 1998 10:31:38 -0800 >Rick, since I don't have any seismo equipment at this time, I am very >interested in the frequencies you are using to copy the singals from USGS and >DWR. Any chances of you posting them here? Thanks. Bob W6JRF@....... I would be happy to send you the list. It is rather large to post here. I originally got the info from Larry. Am not sure where you live. The main frequencies I use here in central California are... 164.65, 164.845, 163.605, and 217 MHz. The 217 MHz carrier re-transmits at least 6 seismometers from the San Luis area on 217Mhz. The signal is beamed to the CHP office in Merced. It then it re transmitted again by microwave to the Sacramento Department of Water Resources office. I can detect most quakes from Mammoth that are greater than 1.9. This method of quake watching does not really have the accuracy for real science. It is great for "earth watching". I suspect that with some better filtering and a program written just for this purpose would work quite well. Still not bad for a sound card and a free program. I use FFTdsp for long-term monitoring. It has marginal resolution and creates some rather large disk files when saving. There is no way to trigger an event. (Any ideas from any of the software types out there?). There is a small registration fee for this program. http://www.webcom.com/~af9y/#Bullet 5 When working is the office I use GRAM32. It does have very good resolution, filtering, save wave, and save data points. I wish that it was able to trigger a save from an event threshold setting. This is a well written program and is freeware. It is frequently updated. As mentioned in a earlier post, Santis is a great analysis tool. Santis will do fft, wavelets and much more. http://www.physiology.rwth-aachen.de/bs/signal/santis/ ------------------------- Michael D wizard@......... N6EGQ Tuolumne, CA ------------------------- "With our ears may we hear what is good." Mundaka _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Re: .WAV files Date: Mon, 12 Jan 1998 07:56:39 At 10:07 PM 1/10/98 -0800, you wrote: >Rick > I tried Gram32.I like it. It's small and I have been looking for a >program that produces a spectrogram. Do you or anyone else know what the >PCM or WAV format is? I always wanted to review recorded quakes this way >(without writing the program myself). I would like to adapt some of my >recorded events for spectrogram viewing. I was using it last night. It is 11k sampling rate mono. I like it too and still havn't got it working just right. Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: VBB Seismometers schematic Date: Mon, 12 Jan 1998 08:02:43 Sean Was looking at the schematics of the limiting amp from your web page and saw what looks like a typo. Is the dioed bridge shorted on perpose? I have never seen one like that. Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Re: Meteorite Impact in Denver, CO. Date: Mon, 12 Jan 1998 08:21:00 >Am checking...various meteorite web sites...only indefinite chatter in cosmic >chat room....something like there May have been one about 12:10 Am m.s.t., >boom, softball size....would not rely on this as definite. No other >references >found. Dewaine What is the server on the cosmic chat. Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Add another tool to the S-T seismo? Date: Mon, 12 Jan 1998 12:37:53 -0700 Hi group, This idea came from my brother Robert Lamb in Texas afew days back....however,...I think it was mentioned once in past PSN notes, but not elaborated on thereafter. Simply use a carpenters level as the seismo boom. Most are sturdy with an "I" beam construction and naturally bubble levels which could be used to check the "zero". They come in a huge variety of aluminum, plastic, wood/metal combos, varying lengths, with either open "I" or closed box ends. Weight considerations would dictate a gravitation toward the lighter or thin wall cheapies. The prices of simple aluminum stock compared to cheap levels is inviting for comparison consideration of the wallet. Think about it awhile..... Now.....if there was a way to solder to the carbon in carpenters pencils................. :>) Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Cosmic Chat Room reference Date: Mon, 12 Jan 1998 12:56:00 -0700 Norman, The cosmic chat room is on http://www.meteoritecentral.com/ Upon opening the above, check on the left, look for the red letter word...Weekly!.... This chat only operates on Sundays from 6 pm Pacific Daylight Time....don't know when it ends. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: VBB Seismometers schematic Date: Mon, 12 Jan 1998 14:16:46 -0600 (CST) Norman, The diode brige is shown with a DOTTED line across it for when no limiting is desired, but the dots turn into a line looking like a short when the drawing is scanned, etc. Thanks for the pointer; I'll try to make sure that important details don't get lost. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: boom structure Date: Mon, 12 Jan 1998 14:23:49 -0600 (CST) Meredith, A point about the boom structure is that it must have relatively small net mass WRT the seis mass, or the Cm (center of mass) moves well away from the force transducer. Your point about rigity, etc, is important, but I manage with a 1" wide x 1/2 deep channel of 1/16" aluminum; a 6 ft length is only a few $$. Also, BTW, I have your SASE, but I haven't had a chance to take a couple of polaroids of the LP vertical for you. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Dennis Eckert" Subject: Re: .WAV files Date: Mon, 12 Jan 1998 12:08:09 -0800 Rick, Re Santis, how does one read the doc files? They have an extension of PS. Any idea what format that is? -- Dennis _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: .WAV files Date: Mon, 12 Jan 1998 15:14:02 -0600 Dennis, The .PS extension is a postscript file. You need to copy the file to a postscript capable printer or find a postscript viewer. Jim Hannon deckert7@....... on 01/12/98 02:08:09 PM Please respond to psn-l@............. To: psn-l@............. cc: (bcc: James M Hannon/CedarRapids/Collins/Rockwell) Subject: Re: .WAV files Rick, Re Santis, how does one read the doc files? They have an extension of PS. Any idea what format that is? -- Dennis _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: lahr@.................. Subject: Re: .WAV files Date: Mon, 12 Jan 1998 14:33:04 -0700 (MST) Dennis, A .ps postscript viewer can be found on shareware.com http://search.shareware.com/ Search for gs261ppc.zip JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Re: boom structure Date: Mon, 12 Jan 1998 14:35:17 -0700 S-T Morrissey wrote: > Meredith, > A point about the boom structure is that it must have relatively > small net mass WRT the seis mass, or the Cm (center of mass) moves > well away from the force transducer. Your point about rigity, etc, > is important, but I manage with a 1" wide x 1/2 deep channel > of 1/16" aluminum; a 6 ft length is only a few $$. > > Also, BTW, I have your SASE, but I haven't had a chance to take > a couple of polaroids of the LP vertical for you. > > Regards, > Sean-Thomas > > Sean-Thomas,... OK and thanks for the reply, it seemed to bean interesting approach with the carpenters level. Is their a crude working ratio of Boom versus Mass weight available or a guesstimate you're aware of? I.e.....boom 1, mass 50, or thereabouts? Like, 50Mass:1Boom weight? Its probably higher, but I don't know. OK on the polaroids of the LP vertical. That will be very helpful as I have no manuel on the vertical. I got it about 25 years ago and had to disassemble it at the time, due to moving and storage and more damage prevention & etc. It turns out after all that time.....I forgot where all the parts go! The LP horizontals are a snap compared to the vertical Sprengnether. The polaroids will help I'am sure, or I can always trapse over to the NEIC branch in Golden and look at the one they have on display cases. They have alot of old timers behind the glass there. If anyone is in Denver area, check them out. The machine work of all of them is wonderful, including the early brass seismometers there. Thanks Sean, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: NIC Circuit Date: Mon, 12 Jan 1998 15:07:28 -0800 Meredith -- The negative impedance converter (NIC) is a fairly simple op-amp circuit. I've put a schematic of it at: http://www.jps.net/karlc/nic.gif The schematic says that the two R's must be well matched. In reality, the output impedance is -(Z * R1 / R2), so a fine adjustment of R1 or R2 could allow you to tweak the impedance to just what you want. The idea is to have the coil's resistance (plus lead wire resistance) exactly matched by the negative output impedance of the NIC. If the impedance of the NIC is nearer to zero than the coil, the system will oscillate, so adjust just shy of that. The copper wire in the coil will change resistance with temperature, so it might be good to construct R3 out of copper wire and mount it near the drive coil to compensate. This will also help cancel thermal emf's generated by dissimilar metals associated with resistors. Use as good an op-amp as you can get (chopper stabilized?). You can reduce the bandwidth by putting a capacitor across R2. Use the op-amp's output to feed the a/d. It is proportional to current in the coil, which is proportional to acceleration. Sean-Thomas' post yesterday makes me think that a loudspeaker may not be a very good thing to use by itself due to the damping of its suspension. I'd still try it to see how it works, though. But as he suggests, using the coil and magnet from the loudspeaker would save a lot of work. If you decide to give it a try, let us know how it works. And if you have any questions, please ask. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Paul Subject: LA Felt Report Date: Mon, 12 Jan 1998 15:14:31 -0800 Hi All, For anyone who might be interested, last night in the Sherman Oaks hills, we felt the Panorama City quake in a B-I-G way. Sounded initially like someone dropped a boxcar on the house (P, no doubt) followed by 20-25 seconds of vigorous shaking, getting harder and softer, harder and softer, 'til it died out about ten minutes later completely. This no doubt was the sine-like structure of the S. The initial jolt was -very- loud, a BANG resembling a car accident, (more like a semi accident!) probably in the 92-102 ADb power range in amplitude as perceived by us inside the house. I estimate we were 4-6 miles South and 2-3 miles west of the epicenter. Exciting, but grim, a very real reminder of the convulsions we endured in '94. Though this is a Scientifically-oriented forum, I wanted to point out, that long before the science of Plate Tectonics was even postulated; in the twenties and thirties, Edgar Cayce predicted such a sequence as we experienced, i.e. 1. Disturbances in the South Pacific (Vanuatu?), 2. Followed by eruptions and/or disturbances at Etna, 3. Followed by California. Just something to mull over, no? I realize there are things going on all over the globe on a daily basis of some consequence, but I did find it interesting that the most noted sequences roughly followed this pattern... Please, no vegetable or beer can throwing... -- Stephen :^) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: CIO-DAS08/JR A/D & EMON Date: Mon, 12 Jan 1998 05:29:34 -0800 Hi Francesco Most cards have an IO address setting. I use between 300-31F hex (prototype card). With the DAS08/JR if you are using a port I thing you would use the port address (LPT1,LPT2, COM1 etc). Let me know what port you are using and I can check. Barry Francesco wrote: > > Hi guys, > I'm installing CIO-DAS08/JR A/D for one of my sensor. > > It's need that I know the right A/D I/O address for setting Emon compatible > software (downloaded from Bob Hammond ftp-side) > or if these is automatically recognized by the programm. I want to know too > the best setting of software: sample, noise, buffers ecc.ecc. > > Thank you very much. > Regards > Francesco Nucera > Osimo - Italy > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: .WAV files Date: Mon, 12 Jan 1998 05:40:53 -0800 Rick EMON has a threshold setting. I thing there is a parallel port hardware settup for it if you don't have a board. Ted or Steve Hammond know more about the port configuration. I am running EMON with satisfaction. I am also running a Quick Basic trigger program I wrote simultaneously which runs overlapping FFT's and looks for variations from a running average background. I can pick up more than with a simple threshold. Also if the frequencies you mentioned are different than that refered to in Larry's site I would also be interested Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: .WAV files Date: Mon, 12 Jan 1998 05:47:19 -0800 Norman I also like it. The problem I had was that when I used a program called COOLEDIT to save the quake file as a WAV file The amplitude changes. I don't mean simple gain I mean the event looks like it clips. A Mammoth event with distinctive P & S amplitudes come out with similar amplitudes in GRAM32. It looks like maybe it's plotting a log vertical scale.???? Any ideas out there? Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: bob@................. (Bob Hammond (USGS-AVO Geophysicist)) Subject: Re: CIO-DAS08/JR A/D & EMON Date: Mon, 12 Jan 1998 15:46:45 -0900 Francesco, Set your A/D I/O address to 768 as is shown in the emon.opt file: FirstSeismometerAddress = 768 (decimal i/o address) and note the comment Ted Blank put right above the addressing lines which says that most pc i/o addresses are in hex but EMON wants decimal so 300h = 768 decimal. hope this helps, Bob Hammond APSN Fairbanks _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: kathy mortensen Subject: recorded 2 big quakes Date: Mon, 12 Jan 1998 16:55:44 -0700 recorded the 6.2 central Chile quake at 02:26:33 +/- 1 sec. recorded the 6.7 Fiji Islands quake at 08:48:21 +/- 1 sec. SKM Pilot Hill, Calif. USA lat 38.828N lon 120.978W _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Francesco Subject: Re: CIO-DAS08/JR A/D & EMON Date: Tue, 13 Jan 1998 02:12:53 +0100 Hello Barry I have inducted the card in an ISA free slot of my 386PC that coincides to serial port. However, I could induct the card in LPT1 that I don't use for stamp. The standard address of CIODAS08JR is 300 hex. Must I write this address in EMON.OPT lines? There is a problem that I don't succeed to resolve. The problem is that if in EMON.OPT I choose the option "NORMAL" in the line operating mode line of the input data, the program begins to run but it stop immediately ! With the RANDOM option the program is ok, but it don't register the data from the sensor. Give me your evaluation. I thank you so much FRANCESCO NUCERA OSIMO - Ancona - ITALY Lat. 43 29" E - Long. 13 29" E _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: CIO-DAS08/JR A/D & EMON Date: Mon, 12 Jan 1998 06:46:28 -0800 Francesco Bob is right. Try decimal rather than hex. "Normal" is ok. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: wizard@......... (Rick Jerome) Subject: Re: .WAV files Date: Mon, 12 Jan 1998 17:51:58 -0800 At 12:08 PM 1/12/98 -0800, you wrote: >Re Santis, how does one read the doc files? They have an extension of PS. >Any idea what format that is? You need to download a copy of Ghostview32 version 2.2. It is available from a variety of sources. File to look for is GSVIEW.exe. Can't remember where it was downloaded from. Do remember that it was a confusing maze to find the right version. I suppose I could e-mail it to you if your provider allows large file downloads. ------------------------- Michael D wizard@......... N6EGQ Tuolumne, CA ------------------------- "With our ears may we hear what is good." Mundaka _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: Re: CIO-DAS08/JR A/D & EMON Date: Mon, 12 Jan 1998 21:40:47 EST Francisco Nucera: I have the same A/D board and obtainted the specially formatted EMON developed by Ted Blank for Bob Hammond. It is already configured to work with this particular A/D card and uses a First Seismo Address of : 768. It should run right off the bat with this number. Lots of luck Jim Allen Cerritos, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ted Blank Subject: Re: CIO-DAS08/JR A/D & EMON Date: Mon, 12 Jan 1998 19:01:12 -0800 (PST) Francesco, You must enter the address of the card in decimal in the EMON.OPT file. 300 Hex corresponds to 768 decimal. Please try that and tell me if you have any more problems. Regards, Ted > > Hello Barry > > I have inducted the card in an ISA free slot of my 386PC that coincides to > serial port. However, I could induct the card in LPT1 that I don't use for > stamp. > The standard address of CIODAS08JR is 300 hex. Must I write this address in > EMON.OPT lines? > > There is a problem that I don't succeed to resolve. The problem is that if > in EMON.OPT I choose the option "NORMAL" in the line operating mode line > of the input data, the program begins to run but it stop immediately ! With > the RANDOM option the program is ok, but it don't register the data from > the sensor. > > Give me your evaluation. > I thank you so much > > > > FRANCESCO NUCERA > OSIMO - Ancona - > ITALY > > Lat. 43 29" E - Long. 13 29" E > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: .WAV files Date: Mon, 12 Jan 1998 21:07:25 -0600 barry lotz wrote: > > Norman > I also like it. The problem I had was that when I used a program > called COOLEDIT to save the quake file as a WAV file The amplitude > changes. I don't mean simple gain I mean the event looks like it clips. > A Mammoth event with distinctive P & S amplitudes come out with similar > amplitudes in GRAM32. It looks like maybe it's plotting a log vertical > scale.???? Any ideas out there? > Barry, I think the problem is that the quake file doesn't always have an even number of bytes in the header. This causes the 16 bit data to be read out of byte order. I wrote a simple c program to strip off the header from to quake files before using cooledit. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: NIC CIRCUIT Date: Mon, 12 Jan 1998 20:03:59 -0700 Karl Cunningham, Thanks for the reply msg and schematic, and the effort you've given. I think that somewhere down the road of time I'll devote more time to this approach on an experimental basis. I'am definitely weak on electronics, but I think I understand most of your presentation. I think it will be fun to fuss with. I think its obvious that the schematic symbol Z means R3 feed back coil and that -Z means the drive/pickup coil connection to input IC and the opposite -Z coil end to common ground? ...........Yes.....I'am that bad....at electronics. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: recorded 2 big quakes Date: Tue, 13 Jan 1998 16:23:55 +1200 At 04:55 PM 1/12/98 -0700, you wrote: >recorded the 6.2 central Chile quake at 02:26:33 +/- 1 sec. >recorded the 6.7 Fiji Islands quake at 08:48:21 +/- 1 sec. >SKM >Pilot Hill, Calif. USA >lat 38.828N lon 120.978W hi kathy , great stuff, just check ur times tho the fiji event was a lot earlier than u stated i presume a typo on ur part..... or u were quoting local times NOTE: if local times they dont mean anything to anyone else around the world. get urself a 24 hr clock and have it set to UTC universal time so the rest of us can make use of ur times otherwise keep up the good work and welcome to the world of amateur seismology 98/01/12 16:36:21 15.64S 179.66W 33.0 6.7Ms A FIJI ISLANDS REGION when u are ready it would be good to get some station setup data from u so i can add u to the map and database of worldwide stations go to http://psn.quake.net/dave/map.htm and below the world map u will find a list of the info i am after for the database copy and paste that list into ur e-mail prog and fill in ur info Many thanks 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: kathy mortensen Subject: Re: recorded 2 big quakes Date: Mon, 12 Jan 1998 20:18:23 -0700 David A. Nelson wrote: > > At 04:55 PM 1/12/98 -0700, you wrote: > >recorded the 6.2 central Chile quake at 02:26:33 +/- 1 sec. > >recorded the 6.7 Fiji Islands quake at 08:48:21 +/- 1 sec. > >SKM > >Pilot Hill, Calif. USA > >lat 38.828N lon 120.978W > > hi kathy , > great stuff, just check ur times tho the fiji event > was a lot earlier than u stated i presume a typo on ur part..... or u > were quoting local times > > NOTE: if local times they dont mean anything to anyone else around the > world. get urself a 24 hr clock and have it set to UTC universal time > so the rest of us can make use of ur times oops!! Just testing the psn waters and am very interested!! I'll do better as the years go by -- I hope! Thanks for the welcome. But yes the times were local pst. Chile should have been 10:26:33 +/- 1 sec UTC Fiji 16:48:21 +/- 1 sec UTC and maybe +/- a couple more sec until I get a little more experience in reading the wave forms!!! Stephen K. Mortensen (SKM) My wife Kathy sign us up to the server and we just keep it that way. She is involved with disaster preparedness. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: boom structure Date: Mon, 12 Jan 1998 22:39:53 -0600 (CST) Meredith, There is no magic ratio of boom mass wrt main mass. Technically, since we have hinged suspensions, we all have rotational systems, and should be figuring rotational angles and torqes about the hinge, etc. (Fortunatley our displacements and therefore our angles are very small, so we can consider our sensors as simple translational systems, and pick a handy reference point, like the center of the main transducer. The closer that the center of mass of the boom + main mass is to that point, the better our approximations are.) Considering the torques about the hinge: the main mass exerts L*M, where L is the boom length. The boom exerts 0.5*L*B, if the Cm(b) of the boom mass B is at the center of L. So the total torque about the hinge is (L*M + 0.5*L*B) or L*(M + 0.5*B). So if we pick M=450gm and B=100gm (about what the Beta sensor here has), we have a torque of L*500 gm. But this is equivalent to the angular momentum of the whole boom + mass system, wrt its' center of mass, (as if all the mass were at the Cm.) So: Cm * (450 + 100) = L * 500, or Cm = 0.91*L. So theoretically we should have the transducers at 91% of the boom length from the hinge for this example. Fortunately, it is not a big care unless/ until we want to nail the calibration to better than 10%. I determine the effective mass by leveling the boom and then removing the mass, coil, balance weights, etc, and then stacking up brass test weights above the center of the force coil until it is again balanced; then I total up the test weights. I hope this answers your question. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: .WAV files Date: Mon, 12 Jan 1998 11:24:57 -0800 Jim I wrote a Basic program to strip off the 100 byte header. I got the same thing. It was mentioned to run a program called Ghostview. I found it but was reluctant to run it since it uses a fair amount of memory and I'm worried about uninstalling it if I don't like it. Rick- Does it do more than strip the header? Barry Jim Hannon wrote: > Barry, > I think the problem is that the quake file doesn't always have an even > number of bytes in the header. This causes the 16 bit data to be read > out of byte order. I wrote a simple c program to strip off the header > from to quake files before using cooledit. > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: recorded 2 big quakes Date: Tue, 13 Jan 1998 19:21:35 +1200 >oops!! Just testing the psn waters and am very interested!! >I'll do better as the years go by -- I hope! Thanks for the welcome. >But yes the times were local pst. >Chile should have been 10:26:33 +/- 1 sec UTC >Fiji 16:48:21 +/- 1 sec UTC >and maybe +/- a couple more sec until I get a little more experience in >reading the wave forms!!! >Stephen K. Mortensen (SKM) >My wife Kathy sign us up to the server and we just keep it that way. >She is involved with disaster preparedness. Hi Stephen, Thanks for correcting me, pleased to meet u. Dont take this the wrong way but i'm just a little saddened I thought we must have finally had the first lady amateur seismologist joining our group. . of course I welcome all and everyone the more the merrier so to u and Kathy a big hi there. a suggestion on a 24hr clock I procured some factory seconds, oven clocks they are great decent large digitsand reasonablry small in size. because i am also an amateur (ham) radio operator my radio contacts are also logged in 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) From: Larry Cochrane Subject: Radio Shack's Radio Controlled Clock Date: Tue, 13 Jan 1998 02:28:32 -0800 Hi Everyone, I thought I would document my experience with the new Radio Controlled Clock that Radio Shack is selling for around $40.00. The clock uses WWVB for its time information and I thought I would buy one to see if it could be used for time keeping with my SDR data logging program. As many of you know my A/D card, and software, currently uses WWV or WWVH to keep the computers time accurate to within a few milliseconds of UTC time. I was hoping the new radio clock would be another way PSN stations in the USA could keep accurate time. The clock has two parts to it. One is the main LCD display and an "antenna" that is about 5 inches long. The two are separated with ~3 feet (1m) of wire. I bought the unit some time in early December, and when I first got it, I could not get it to lock up to the time signal. I tried everywhere in my house, nothing. So I set it up in a high place in my house hoping that it would lock some day. I kept checking every day, again nothing. After about a week of this I was getting pretty discouraged. Then one day, just before Xmas, it locked up. It turns out that the people at NIST, who send out the WWVB signal, increased the power of their transmitter from a whopping 10KW to around 20KW (they will be increasing it to 40KW in a few months) on DEC. 19th. This increase was enough for the clock to lock to the signal. At this point I had something to work with. No need to poke around if I can get it to lock.... So I opened the main unit, like any good electronics nerd will do, to see what I could find. I was expecting to find something that looked like a small radio receiver in it. I didn't see anything that looked like one. I then started probing around with an o-scope to see what I could find. All I could find was some LCD drive signals, nothing that could be easily converted to a time reference for SDR. I then look at the signals around the wire from the antenna assembly. There where 4 wires that terminated on the PC board. They are marked VE+, GND, DCF and PON. With the scope I found that +VE had the + battery voltage (two AAA batteries power the unit for a voltage of around 3 volts) on it. The GND was the - battery side. The PON would be at +3 volts when the unit was not trying to lock to WWVB, and ground if it was using the receiver. And the DCF signal had some sort of "digital" signal on it when PON was at GND. The unit tries to lock onto WWVB every 3 or 4 hours. If it can lock onto the signal, or times out in 5 to 10 minutes it sets the PON signal back to +3v. I then open the "antenna" assembly. It turns out that it has the antenna and a complete receiver in it. The assembly has an ~5 inch farad rod, and a coil wound on it, and a small PC board with a potted IC. Since I didn't know what the format of WWVB was, I did know that it was transmitted at the low freq. of 60khz (not mhz), I did an Internet search and found that it has a one bit per second data rate (see http://www.boulder.nist.gov/timefreq/ for more info on WWV and WWVB). To send the time code the transmitter reduces its power by 10db for 200 milliseconds to signal a binary 0, 500ms for a binary 1 and 800ms for a framing mark. The framing mark is sent every 10 seconds. After locating the antenna/receiver in a good location, the unit is pretty sensitive to the orientation and location, I could see the 1 pps data bits on the DCF wire with the scope when the receiver was on. You can force the unit to try and lock on the time signal by turning the unit off and on again. Since the receiver was located in the antenna assembly, and the main unit turns the receiver on and off, I decided to remove the receiver from the main LCD unit and power it my self. I also came up with a simple circuit that would take the DCF output and drive a digital input port on my A/D card or the PC-Labs 711s card. The following web page has the schematic: http://psn.quake.net/wwvbsdr.html. Rather then power the unit at 3 volts (I didn't have a 3 volt regulator on hand) I tried using +5 volts. It seems to work fine despite the extra 2 volts. I then modified SDR to read the signal from the receiver. Since I already had code that recognized a 800ms top of the minute pulse from WWV, I was able to change the code so it could use the 800 ms framing pulses from WWVB. WWVB sends out two back to back framing pulses, one second before the top of the minute, and another one at the top of the minute. SDR uses the two framing pulse to know when the top of the minute happens and uses this mark to keep the system time accurate. It doesn't seem to work as well as my WWV setup put it was able to keep one of my SDR systems accurate to within +-15ms. I can get better accuracy, +- 5 ms, with my $200+ short-wave receiver tuned to WWV on 5.0 MHZ, and outside antenna, but for $40.00, and a handful of parts, +-15 ms is not to bad. If you would like to try the receiver clock with SDR the first thing to do is get one from Radio Shack and see if you can get it to lock in your location. If you can't get it to lock hopefully you can bring it back. If you can get it to lock then build up the interface circuit (or contact me and I can build one for you) and connect it to the digital input port 0 of my A/D card (pin 32 and one of the digital GND pins) or port 0 of the PC-Labs card. You will also need to contact me for a new version of SDR. Regards, Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: .WAV files Date: Tue, 13 Jan 1998 05:46:20 -0600 barry lotz wrote: > > Jim > I wrote a Basic program to strip off the 100 byte header. I got the > same thing. It was mentioned to run a program called Ghostview. I found > it but was reluctant to run it since it uses a fair amount of memory and > I'm worried about uninstalling it if I don't like it. Rick- Does it do > more than strip the header? > Barry > Berry, I think the subject line got used for two discussions. GhostView is a program for viewing .PS or postscript files. This type of file is sometimes used to distribute documentation as it is postscript printer ready. Problem is not everyone has a postscript printer. This has nothing to do with quake files. Try stripping off 101 bytes and see what happens. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ted Blank Subject: EMON V7 available on PSN web site Date: Tue, 13 Jan 1998 06:01:03 -0800 (PST) EMON V7.0 is now available on the PSN website. The list of enhancements include - Support for Larry's PSN-ADC board (both 12 and 16 bit versions) - Support for Computer Boards CIO-DAS08Jr/16-AO 16-bit A/D card - Fix for a bug where data was not saved in the middle of a large event In addition, a complete set of documentation is now available in MS Word format (saved as a Word 2.0 file), and also in Windows WRI as well as text format. (So rry, the text format file won't have the screen captures showing how the progrma s work). If you download the EMON 7.0 package you will get EMON, QUAKEVU, all the utility programs, but the documentation files are packaged separately for folks who don 't want / need them. I've also packaged the QUAKEVU code / documentation by itself for folks who are just displaying files and don't want all the data collection code. The separate QUAKEVU package is also available on the PSN web site. My thanks to Larry for putting up the code. Let me know if you have any problems/questions. Happy quake hunting. Ted _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roger Sorensen Subject: Re: CIO-DAS08/JR A/D & EMON Date: Tue, 13 Jan 1998 07:28:33 -0800 RADIOTEL wrote: > > Francisco Nucera: I have the same A/D board and obtainted the specially > formatted EMON developed by Ted Blank for Bob Hammond. It is already > configured to work with this particular A/D card and uses a First Seismo > Address of : 768. It should run right off the bat with this number. > Lots of luck > Jim Allen > Cerritos, California > Make sure you have the EMON version that runs with the DAS08JR (from Bob). If you don't, EMON will start up, flash the main screen for a split second, and then shut down. If you watch very closely in the upper left hand corner of the screen you'll see a message that says 11 is an invalid type. (11 being the DAS08JR). It's pretty easy to get multiple versions mixed up (I know, because I did that last night ;-) Roger Sorensen Chatsworth, CA USA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: NIC CIRCUIT Date: Tue, 13 Jan 1998 08:24:24 -0800 Meredeth -- You are correct that the drive/pickup coil attaches to the -Z terminal of the circuit, and R3 is a dummy resistor of the same resistance as the coil. -- Karl At 08:03 PM 1/12/98 -0700, you wrote: >I think its obvious that the schematic symbol Z means R3 feed back >coil and that -Z means the drive/pickup coil connection to input IC >and the opposite -Z coil end to common ground? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: Radio Shack's Radio Controlled Clock Date: Tue, 13 Jan 1998 10:43:08 -0600 Larry, This is great! It is a little late maybe but the chip in the Radio Shack receiver part of the clock is made by Temic Semiconductors part number U4223B http://www.temic.de/semi/hn/broadcas/radiocon.htm is a link to the data sheet on the chip. The chip costs about $2.50 each but it maybe hard to get under the minimum order. Running the chip on 5 volts may be pushing it. The data sheet gives 5.25 V as the absolute max . There are a number of time code transmitters in Europe that are more powerfull than WWVB and radio controlled clocks and even wrist watches are very popular there. cochrane@.............. on 01/13/98 04:28:32 AM Please respond to psn-l@............. To: psn-l@............. cc: (bcc: James M Hannon/CedarRapids/Collins/Rockwell) Subject: Radio Shack's Radio Controlled Clock Hi Everyone, I thought I would document my experience with the new Radio Controlled Clock that Radio Shack is selling for around $40.00. The clock uses WWVB for its time information and I thought I would buy one to see if it could be used for time keeping with my SDR data logging program. As many of you know my A/D card, and software, currently uses WWV or WWVH to keep the computers time accurate to within a few milliseconds of UTC time. I was hoping the new radio clock would be another way PSN stations in the USA could keep accurate time. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Dennis Eckert" Subject: Re: .WAV files Date: Tue, 13 Jan 1998 10:03:50 -0800 Thanks for the offer....I downloaded it, and now just have to try it out. Dennis Eckert KB7ST (Amateur Radio Operator) Flies Standard Cirrus sailplane (SV) In Western & Eastern Washington ICQ 4324132 -----Original Message----- From: Rick Jerome To: PSN-L Mailing List Date: Monday, January 12, 1998 7:52 PM Subject: Re: .WAV files >At 12:08 PM 1/12/98 -0800, you wrote: >>Re Santis, how does one read the doc files? They have an extension of PS. >>Any idea what format that is? > >You need to download a copy of Ghostview32 version 2.2. It is available >from a variety of sources. File to look for is GSVIEW.exe. Can't remember >where it was downloaded from. Do remember that it was a confusing maze to >find the right version. I suppose I could e-mail it to you if your >provider allows large file downloads. >------------------------- > >Michael D > >wizard@......... > >N6EGQ > >Tuolumne, CA > >------------------------- > >"With our ears may we hear what is good." > Mundaka > >_____________________________________________________________________ > >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: kathy mortensen Subject: Re: recorded 2 big quakes Date: Tue, 13 Jan 1998 10:39:30 -0700 David A. Nelson wrote: > > >oops!! Just testing the psn waters and am very interested!! > >I'll do better as the years go by -- I hope! Thanks for the welcome. > >But yes the times were local pst. > >Chile should have been 10:26:33 +/- 1 sec UTC > >Fiji 16:48:21 +/- 1 sec UTC > >and maybe +/- a couple more sec until I get a little more experience in > >reading the wave forms!!! > >Stephen K. Mortensen (SKM) > >My wife Kathy sign us up to the server and we just keep it that way. > >She is involved with disaster preparedness. > > Hi Stephen, > Thanks for correcting me, pleased to meet u. Dont > take this the wrong way but i'm just a little saddened I thought we > must have finally had the first lady amateur seismologist joining our group. > . of course I welcome all and everyone the more the merrier so to > u and Kathy a big hi there. a suggestion on a 24hr clock I procured > some factory seconds, oven clocks they are great decent large digitsand > reasonablry small in size. > > because i am also an amateur (ham) radio operator my radio contacts are > also logged in 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 NO LADY SEISMOLOGISTS??? NOW I'M SAD I use a windows 3.1 and 95 program called ATOMIC CLOCK by PARSONS TECHNOLOGY http://www.parsonstech.com to keep track of time as well as set my computer clock by modem. It's a cute little program and was able to pick it up at compusa (I think) for about $15.00. It was in their clearance bin!! SKM _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: Purchasing Seismograph Date: Tue, 13 Jan 1998 14:41:06 -0700 John- In terms of putting together a seismograph for your own use at home, the best source of info I know is the Public Seismic Network (PSN): http://psn.quake.net Otherwise, here is a partial list of homepages of manufacturers of portable autonomous digital seismographs (PADS): http://www.reftek.com/ http://www.kinemetrics.com/index.html http://www.terratechnology.com/ Prices for these products range from about $5k-$20K. Good Luck! -Edward John Paul Martin wrote: > > Dear Sir, > > How do I go about obtaining the manufacturer and purchase price of a > PADS? My Email address is pinecone@............. > > John Paul Martin -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Flexures & Oilcans Date: Tue, 13 Jan 1998 14:40:02 -0800 Hi All -- In thinking about flexures, it seems there may be a natural tendency for microscopic oilcanning (non-linear spring characteristics of the flexure) as it changes from being bent one way to being bent the other way), due to irregularities in the thickness and flatness of the metal. Surely this has been thought of before -- does anyone know how this problem is dealt with in commercial instruments? Do they prevent the flexure from ever being flat by allowing it to only bend one way, or is some other technique used? wondering, Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Francesco Subject: CIODAS08JR & EMON Date: Tue, 13 Jan 1998 23:54:18 +0100 Thank very much Bob, Ted and Jim. The I/O address it's ok and the board seems to function evenly. But I believe to have any other problem. If are not there events, must I see any trace in the screen or no? I see that the program runs, but I don't see any trace and no file is saved. Is that regular? These is the setting values: noise zones = 1% convert per sample = 25 buffers = 4000 Greetings FRANCESCO NUCERA OSIMO - Ancona - ITALY Lat. 43 29" E - Long. 13 29" E _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roseberry Subject: GPS-based timekeeping for your PC Date: Tue, 13 Jan 1998 17:50:51 -0600 Hello group: A while back, this group developed a fairly long thread regarding GPS-based timekeeping. I happened onto the following source for these kinds of products and thought someone on the list may benefit from it. If you are interested in PGS stuff, see http://www.zeli.com for more details; their prices seem reasonable. Regards: Michael J. Roseberry Fort Worth, Texas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: Radio Shack's Radio Controlled Clock Date: Tue, 13 Jan 1998 17:00:44 -0800 The Temic clock part is really a series of three parts of which seem to = be the same with only a difference of number of pins in the packaged = part. Of interest is that the app note shows two ways to use them with = one 60 KHz crystal or two crystals for the IF. In none of the radio = clocks I've seen, have they used the two crystal version--only one. = Cost, no doubt, but there is a significant improvement in performance = with two. As I've mentioned before, the Oregon Scientific "Time = Machine" and the Klockit analog movement unit all use the same RF = decoder it would appear. However, just before I found out about the = Temic chip, I had depotted a Klockit board, and the chip nomenclature = doesn't look like it fits the Temic brand. I know Integrated Display Co = in Hong Kong builds the Oregon Scientific line, and is big enough to = have a custom design done, and since Radio Shack imports a bunch, they = may be using the same chip. Be that as it may, Of the units I have = examined, the Oregon Scientific and the Klockit and information on one = other brand from another experimenter I've talked to, they all have the = 4 wire scheme just as Larry describes for the Radio Shack unit -- = power, ground, signal out, and inhibit. So if you want to start with = something cheaper, get the Klockit unit, it's only $30 and has the same = capability--you just have to slice and dice the circuit board a bit to = get those four connections -- but it really isn't too hard as the RF = section is confined to one end of the board. Be careful about the load = you place on the signal out line. The chip runs on only a few = microamps, so basically can't drive anything. I would suggest the use = of a CMOS buffer (inverter or such) between the data signal and your = computer input. I don't know the impedance of the line on Larry's = board, but running from 5V will help the driving capability somewhat. I've known about the Temic chips for some time and I'm in the process = of building up just boards to be interfaced to the computer. I have 4 = samples of the Temic SMT chips in my possession that I got last month, = and just got in the 60 KHz crystals last weekend (Digi-Key SE3320-ND = cylinder type watch crystals made by Epson for $1.35 each singles). = Rather than use ferrite rod antennas, I'm going to use a small loop, = which is more available and repeatable and should increase the = sensitivity to boot because the effective antenna height of the various = clocks is very small because they use such small antenna rods. I'll let you know how it works out when I finish. Charles R. Patton, Editor, Geo-Monitor patton@......... Sincerely yours, Charles R. Patton, Sr. Princ. Eng. Charles.R. Patton@....... fon: 714-932-7476 fax: 714-932-5995 Western Digital Corp. M/S 431 8105 Irvine Center Drive Irvine, CA 92618 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: Radio Shack's Radio Controlled Clock Date: Tue, 13 Jan 1998 19:24:36 -0600 Charles R. Patton wrote: > > > > I've known about the Temic chips for some time and I'm in the process of building up just boards to be interfaced to the com puter. I have 4 samples of the Temic SMT chips in my possession that I got last month, and just got in the 60 KHz crystals las t weekend (Digi-Key SE3320-ND cylinder type watch crystals made by Epson for $1.35 each singles). Rather than use ferrite ro d antennas, I'm going to use a small loop, which is more available and repeatable and should increase the sensitivity to > I'll let you know how it works out when I finish. > Charles, I just found about the Temic chips today after talking to a person at Altera who is using the chip in a class to teach FPGA design. They have a FPGA design that converts the chip output into ASCII time info. He is supposed to be sending me the design and even a working clock for helping him find a source for the ferrite rods. (Amidon) It looks like we will have a nice WWVB time option for PSN soon. I ran out today and bought one of the Radio Shack clocks. :( -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: Flexures & Oilcans Date: Tue, 13 Jan 1998 06:36:20 -0800 Karl Are you refering to possible hysteresis of the metal? Barry Karl Cunningham wrote: > > Hi All -- > > In thinking about flexures, it seems there may be a natural tendency for > microscopic oilcanning (non-linear spring characteristics of the flexure) > as it changes from being bent one way to being bent the other way), due to > irregularities in the thickness and flatness of the metal. > > Surely this has been thought of before -- does anyone know how this problem > is dealt with in commercial instruments? Do they prevent the flexure from > ever being flat by allowing it to only bend one way, or is some other > technique used? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: CIODAS08JR & EMON Date: Tue, 13 Jan 1998 06:40:48 -0800 Francesco Check which channel you are monitoring (F7 on my version) and make sure you have the correct entries for the other two of the three possible channels in the .OPT file. Barry Francesco wrote: > > Thank very much Bob, Ted and Jim. > > The I/O address it's ok and the board seems to function evenly. > But I believe to have any other problem. > If are not there events, must I see any trace in the screen or no? > I see that the program runs, but I don't see any trace and no file is > saved. Is that regular? > These is the setting values: > noise zones = 1% > convert per sample = 25 > buffers = 4000 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: Radio Shack's Radio Controlled Clock Date: Tue, 13 Jan 1998 06:49:37 -0800 Charles I was interested in a low power accurate clock for my remote site , where I will be using a SBC. I would be interested in what you come up with. I was going to buy a Radio Shack clock but wasn't sure how to access the output to the display to input to my acquisition program. Barry Charles R. Patton wrote: > > > > I've known about the Temic chips for some time and I'm in the process of building up just boards to be interfaced to the com puter. I have 4 samples of the Temic SMT chips in my possession that I got last month, and just got in the 60 KHz crystals las t weekend (Digi-Key SE3320-ND cylinder type watch crystals made by Epson for $1.35 each singles). Rather than use ferrite ro d antennas, I'm going to use a small loop, which is more available and repeatable and should increase the sensitivity to > I'll let you know how it works out when I finish. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: Radio Shack's Radio Controlled Clock Date: Tue, 13 Jan 1998 18:27:54 -0800 At 10:43 AM 1/13/98 -0600, James M Hannon wrote: >Larry, >This is great! > >It is a little late maybe but the chip in the Radio Shack receiver part of >the clock is made by Temic Semiconductors part number U4223B Are you sure its the U4223b? This versions has an A/D convert built in to the chip and is meant for a direct connect to a micro processor. This would take more lines between the main unit and the receiver. >http://www.temic.de/semi/hn/broadcas/radiocon.htm is a link to the data >sheet on the chip. The chip costs about $2.50 each but it maybe hard to >get under the minimum order. Running the chip on 5 volts may be pushing >it. The data sheet gives 5.25 V as the absolute max . > >There are a number of time code transmitters in Europe that are more >powerfull than WWVB and radio controlled clocks and even wrist watches are >very popular there. Unfortunately they all use different formats and / or frequencies. Too bad they did'nt standardize them... -Larry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: flexure material Date: Tue, 13 Jan 1998 20:31:18 -0600 (CST) Karl et al. My experience with the flexures in commercial instruments has been that they are obtained from flat or rolled spring-steel or phosphor-bronze stock, and cut to length or size such that the sides that are cut are within the clamping mechanism: ie the portion that flexes is "original" rolled and hardened material. With regard to larger hinged "boom and mass" structured sensors, I am unaware of any major problem with latent curvature that would cause non-linearities. Actually, the spring constant of the flexures is quite small compared to the main suspension in a vertical, and weak compared with the gravitational restoring forces in a horizontal, where thin taught wires are preferred. If flexures are used in a horizontal, like the early sensors, they are installed so that any latent curvature will cancel in the crossed hinge arrangement . However, with the compact "geophone" type structures, made with usually etched circular springs, latent curvature is the name of the game. This is why simply inverting one of the 10 leaf springs in an L4-C can kill it; also why abuse can cause a partial inversion of a spring, changing the period to something very short. Which, of course, brings me to my favorite subject: in a fully fedback seismometer, the behavior of the hinges and springs doesn't show up in the transfer function, so it is a "don't care" item, generally speaking. By way of example, I just posted the data from the 10 Jan M=6.4 Guatemala quake, including a figure that compares the homemade STM-8 seis with the German-made STS-1s. I'm sure that there is a MAJOR difference between their hinges and my weatherstrip pieces, but with similar feedback, the data are basically identical in form, spectra, and amplitude (I've scalled them in microns/second), except for azimuthal variations of the stations wrt the earthquake source mechanism. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: STM-8 Bronze spring? Date: Tue, 13 Jan 1998 19:34:54 -0700 Sean-Thomas, Am curious about the "main" bronze weatherstrip spring under the boom. In past reviews of msgs, you state it is 12" X 3". What is the thickness of it, and where did you obtain it? Any possible other sources...i.e., machine shop supply? Shim stock in hobby shops? Could other materials, serve the same purpose with or without degradation of seismo output or metal fatique? I.e.,...flat sheet metal...galvanized sheet metal...etc.? I've only hit a local The Home Depot, but nothing approached that size. Perhaps anything that would provide the restoring force necessary.....and a To of 2-4 seconds.....may work? Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: STM-8 steel spring! Date: Tue, 13 Jan 1998 21:05:39 -0600 (CST) Meredith, The main spring is spring steel from a drywall taping knife found in the PAINT department of Builders Square for about $8. It has a plastic handle, and is 0.018" thick, 3"wide, 12" long. There is nothing magic about the size; I just built a seismometer around it. One can buy the material in 70ft rolls from McMaster Supply. It needs to be hardened spring steel, though, since it is a spring. And my experience with this particular piece is that when it is bent to about a 5" opening, it exhibits some "zero length" behavior, where the force is somewhat constant over a short change in the length of the opening, allowing for a moderately long mechanical period without instability. The hinges, however, are phosphor-bronze weatherstrip, as are the flexures at the lower mount of the main leaf spring. It is 0.005" thick, and I used a width of 0.375 for the hinges and 0.75 for the spring flexure. I have been working on a detailed description of the mounting of the leaf spring, but I am not satisfied with the details of it yet. I did scan another photo to the web page that shows the hinges and some of the lower spring mounting detail. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: FM transmission Date: Tue, 13 Jan 1998 08:14:01 -0800 To all On a separate note; Do to my confusion about what was and wasn't allowed by the FCC with regards to transmitting data over the airwaves, does anyone know what the noise would be by sending analog signals(<20hz) over an FM transmitter? It is better practice to send "noise immune" digital data rather than analog data, but our signals are below the audible level. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: Re: EMON V7 available on PSN web site Date: Tue, 13 Jan 1998 21:49:09 EST TED BLANK: I just saw your posting about the availability of the new EMON package. I for one would like for you to know how much your efforts and contributions are appreciated. Thank you very very much. Jim Allen Cerritos, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: Radio Shack's Radio Controlled Clock Date: Tue, 13 Jan 1998 21:17:35 -0600 Larry Cochrane wrote: > > > Are you sure its the U4223b? This versions has an A/D convert built in to > the chip and is meant for a direct connect to a micro processor. This would > take more lines between the main unit and the receiver. > > -Larry > No I am not certain that is the exact chip. Maybe Charles Patton can clarify it for us. They could be using just one bit of the A/D output or just squaring up the AGC output. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: STM-8 Steel Spring Date: Tue, 13 Jan 1998 21:28:19 -0700 Sean-Thomas, AAAHHHH the light goes on! Somehow, I transposed the dry wall knife as being at the back of the boom and the spring under the boom as being something else for a long month! I'll admit my gross error...and laughing at myself, really! I was mentally fixating on putty knifes! The spring is sprung.....thanks. Thanks for the other info, I'll be sure to take my micrometer along so I don't goof up as bad again. Thanks for all the work and effort you have put in over the long haul on this project, and although its been straining for people like me, I do appreciate all of this very, very much. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Seisguy Subject: Fwd: Italian Volcano Shows Lava Activity Date: Tue, 13 Jan 1998 23:24:30 EST This is being broadcast on the local L.A. news this evening also. Mike 
Italian Volcano Shows Lava Activity


.c The Associated
Press


 CATANIA, Sicily (AP) - The ground stayed quiet but experts remained alert
Tuesday for a possible eruption of Mount Etna, Europe's tallest volcano.

Two small lava streams continued to flow after several minor earthquakes
registered Friday evening and Saturday at the volcano in eastern Sicily.

Vulcanologists called the seismic activity serious, and said they were
watching for a potential eruption.

Etna's last major eruption came six years ago. No plans for evacuation have
been announced.

The volcano's slopes are home to several farm villages, and skiers enjoy the
mountain snow.

AP-NY-01-13-98 1711EST


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


 

To edit your profile, go to keyword NewsProfiles.
For all of today's news, go to keyword News.
From: "Al Allworth" Subject: Adjustment screws Date: Tue, 13 Jan 1998 23:03:53 -0800 Hi All, I have found a source of 1/4 X 80 pitch adjustment screws with brass nuts for $2.00 each at: http://www.lasersur.com/laser/accessories.htm With the 80 pitch thread it would probably not be necessary to use the differential thread construction. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Walt Williams" Subject: PSN - STM-8 steel spring & Zero Length Spring? Date: Tue, 13 Jan 1998 23:19:09 +0000 Hello Sean-Thomas Morrissey, Marquee: >>STM : Sean-Thomas Morrissey >>WW : Walt Williams ------- Forwarded Message Follows ------- Date: Tue, 13 Jan 1998 21:05:39 -0600 (CST) From: S-T Morrissey To: psn-l@............. Subject: STM-8 steel spring! Reply-to: PSN-L Mailing List >>STM The main spring is spring steel from a drywall taping knife..... <----- deletia -----> ......my experience with this particular piece is that when it is bent to about a 5" opening, it exhibits some "zero length" behavior, where the force is somewhat constant over a short change in the length of the opening, allowing for a moderately long mechanical period without instability. Regards, Sean-Thomas >>WW In literature of which some kind PSN-Ls have referred me, for the construction of gravimeter instruments, there is frequent reference to 'zero length springs'. I noticed you mention the drywall blade / spring metal can be made to exhibit 'zero-length' by flexing the metal. I am curious to know more detail about 'zero-length' characteristics, and why this is desirable. Could you explain how a 'zero-length' spring might behave? The whys would be interesting to know. Thank you. Walt Williams, 98.01.13 dfheli@.............. Canoga Park, (LA suburb), California USA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: Flexures & Oilcans Date: Wed, 14 Jan 1998 00:05:31 -0800 Barry -- Yes, the effect of what I'm thinking of is hysteresis. I'm not sure just how to describe it except that it is similar to the action of the bottom of an oil can that "pops" in and out as you squeeze it. It's caused by an excess of metal in one area of the sheet, which means it must bulge either up or down. As the metal is flexed, this bulge can change from up to down and back, causing a non-linear displacement/force curve and hysteresis. -- Karl At 06:36 AM 1/13/98 -0800, you wrote: >Karl > Are you refering to possible hysteresis of the metal? > Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Francesco Subject: Re: CIODAS08JR & EMON Date: Wed, 14 Jan 1998 09:14:55 +0100 I checked the channel viewing: it's 0 and ok. The other possible channels are not installed and so the set in .opt file at line address 2^, 3^ ch. is 0. So, I'm using the 0 ch. and in pin connector i've choosed: pin n=B0 1 for input analog(positive) and pin 20 for ground. Is it right? If the connector from sensor is disabled from female board conn. the signal is a blank continuos line. When i connect the sensor that line disappear. Why?????? At last: in .opt file there is an option about ADC values. But the choose in the 3 option where is? Graciously Francesco At 06.40 13/01/98 -0800, you wrote: >Francesco > Check which channel you are monitoring (F7 on my version) and make >sure you have the correct entries for the other two of the three >possible channels in the .OPT file.=20 > Barry > >Francesco wrote: >>=20 >> Thank very much Bob, Ted and Jim. >>=20 >> The I/O address it's ok and the board seems to function evenly. >> But I believe to have any other problem. >> If are not there events, must I see any trace in the screen or no? >> I see that the program runs, but I don't see any trace and no file is >> saved. Is that regular? >> These is the setting values: >> noise zones =3D 1% >> convert per sample =3D 25 >> buffers =3D 4000 > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the=20 >message: leave PSN-L > > FRANCESCO NUCERA OSIMO - Ancona - ITALY Lat. 43 29" E - Long. 13 29" E _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: Speaker coil-based seismos Date: Wed, 14 Jan 1998 08:32:17 -0800 I have found used speakers at swap meets that have screwed-together magnet assemblies. Usually a disc-shaped ceramic magnet (with a hole in the center) sandwiched between two metal plates with screws between the metal plates. Some even have threaded holes in which to insert jack screws to controllably force the pieces apart. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: bob ogburn Subject: Re: Adjustment screws Date: Wed, 14 Jan 1998 09:29:53 -0800 the correct URL is: http://www.lasersur.com/laseraccessories.htm Al Allworth wrote: > > Hi All, > > I have found a source of 1/4 X 80 pitch adjustment screws with brass nuts > for $2.00 each at: > http://www.lasersur.com/laser/accessories.htm > > With the 80 pitch thread it would probably not be necessary to use the > differential thread construction. > > _____________________________________________________________________ > > 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: A Lunchpail Amateur Seismologists Best Story Date: Wed, 14 Jan 1998 12:30:27 -0700 Hi group, Back in the mid 1960's, I first got interested in amateur seismology mainly due to the series of Denver, Colo. area earthquakes induced by the Army's Rocky Mountain Arsenals fluid injections by a well on the northeast outskirts of Denver. For me these were as close as you can get the majority being Mag 2 or so. These quakes seemed to be fairly often, and over time I tried to develop a sensitivity for them regardless of personal activity. For me in those days, amateur equipment was essentially not available due to price and wallet scantiness for other than daily living costs. My best shot at the time was the Heathkit Company with its discrete parts chart recorder...not to buy...but to build from their schematic. The servo motor I bought from them, the rest of the stuff was salvage here & there. I didn't fare too well, as the circuit often broke down. Chart paper was out of the question; too costly, so I ended up with using a homebrew drum made out of a plexiglass 8" tube, mechanics, and mounting the servo motor over the drum, and yes, the old screw rod translation drive. Yes, breakdowns all the time. My biggest financial purchase at the time, was a set of Sprengnether LP seismometers, so...no problem with that aspect. $240.00,...seems small now, but for the time that was about 2 weeks of take home earnings. Anyway...this was the first crude seismograph I had, and the excitement was very high. I had it setup in the basement. Had a problem with the low gain, but who cares for the minor stuff. Believe me...its hard to ignore the first masterpiece, and I would often sit in an old wooden rocker with footrests and wait for something to show. One night (I forget the year), soon thereafter, I was sitting and watching and all stretched out on the rocker....and fell asleep. >From a very slow awakening state, I realized I was slowly being rocked in the chair by a period of perhaps 15 seconds. At first, I thought someone was gently rocking me, and slowly turning...there was no one there! A quick glance at the drum drum showed long period surface waves being recorded! The quake date I don't remember, but I think it was off the coast of Portugal in the Atlantic, perhaps 7.8 ~, in the latter 60's. This quake made seiches in lakes in northern europe, and also made me a living mass and sensor in a way also. So.......enough of mine......whats your best story? Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: FM transmission Date: Wed, 14 Jan 1998 13:43:27 -0600 Barry, Directly FM modulating a radio carrier with the low frequency seismic signals is not a good idea. There are all sorts of problems with the receiver and transmitter design that would cause this to be very unsatisfactory. Most of these problems are solved by modulating the radio carrier with an audio frequency signal that is itself fm modulated by the seismic signal. I am not sure what you are referring to about what is or is not allowed by the FCC but: If you are not already a licensed Amateur radio operator you might want to consider getting at least the no code amateur radio operators license. This license will allow you to operate all sorts of radio transmitters and transmit digital data or analog seismic signals. You do have to pass a written test but it is not too hard after reading through the license book a couple of times. http://www.arrl.org is a good place to start for information. Also http://www.tapr.org is group involved in digital radio communications. Jim Hannon WB0TXL gbl@....... on 01/13/98 10:14:01 AM Please respond to psn-l@............. To: psn-l@............. cc: (bcc: James M Hannon/CedarRapids/Collins/Rockwell) Subject: FM transmission To all On a separate note; Do to my confusion about what was and wasn't allowed by the FCC with regards to transmitting data over the airwaves, does anyone know what the noise would be by sending analog signals(<20hz) over an FM transmitter? It is better practice to send "noise immune" digital data rather than analog data, but our signals are below the audible level. Barry _____________________________________________________________________ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Dewayne and Linda Hill Subject: Re: A Lunchpail Amateur Seismologists Best Story Date: Wed, 14 Jan 1998 13:01:08 -0700 Hi Mereidth, Good to get your note last night and your natural earth resonant rocker story was quit good also. Well I just got back to the office from hardware store (another $20 on the project.) I pickup everything I need to rebuild the boom with the exception of the coil and magnet. I sent Larry an E-Mail about ordering his coil/magnet. After re-reading my description about the Lehman I can see how you misunderstood part of the write up. I boom is not at 37degs., the supenition wire is at 37degs. Hope you haven't trying to picture a 37deg boom all night. I bought 5lb. of lead. It looks like steel wool. How is the best way to melt down? Does the lead pour have to be made in one pour or can I do it in several small pours? Well I have to get back to work. Dewayne _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: Radio Controlled Clock Date: Wed, 14 Jan 1998 12:46:52 -0800 I just revisited the spec sheets on the Temic site which you can reach = with: http://www.temic.de/cgi/prod_head.tcl?headline=3DRadio-Controlled+Clock+R= eceivers+ICs&parent=3Dabroadc&ueber=3DCommunication+Ics The four parts available from Temic are: Part Function Key Features Package T4225B Receiver for 40 to 80 kHz Extreme low power consumption Die U4223B Receiver for 40 to 80 kHz 4-bit ADC output SSO20 U4224B Receiver for 40 to 80 kHz Extreme low power consumption SO16L U4226B Receiver for 40 to 80 kHz Extreme low power consumption SSO20 Since I have no intention of doing high production, chip-on-board, the = T4225B is dismissed. The U4223B can do a 4 bit digitization of the AGC and the incoming = signal (these are all TRF receivers with rectification type detectors). = By doing signal processing you can improve the detection capability by = 10 dB (says the spec sheet). But this would require oversampling, at = least a 6 wire interface, and a bunch of processor code. Not sure that = the effort is warranted. So that brings us to the last pair of numbers, = the U4224B and U4226B. The only thing I've been able to figure out = that's different is that the package is a 16 pin vs. 20 pin SOIC. = Anyway these have the 0/1 output controlled by a comparator inside the = chip monitoring the AGC vs. the current signal strength (modulation). They basically are very simple to use. They require 3 non-electrolytic = caps, 1 resistor, 1 tuned antenna, and 1 or 2 60.00KHz crystals. They = use a maximum of 25 uA at 5 V while operating, but the output is = guaranteed for 3 to 4 uA only, which is why I commented about buffering = the output for most uses. I want to expand on my comment about the antenna. One simplistic way of = viewing a ferrite antenna is that its length is its important dimension = and if you have a loop whose side is that length, they become = comparable. Since ferrite rods used in the current radio controlled = clocks on the market are only about 3" or 4" long, then a loop antenna = the size of your hand, can easily best them. And that way you don't get = involved in the temperature curves of the ferrite, or procurement = difficulties. (This is another way of looking at the effective = permeability curves of ferrite rods based on their length/diameter = ratios.) Hope this helps. Charles R. Patton, Editor, Geo-Monitor patton@......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Re: A Lunchpail Amateur Seismologists Best Story Date: Wed, 14 Jan 1998 13:17:10 >I bought 5lb. of lead. It looks like steel wool. How is the best >way to melt down? >Does the lead pour have to be made in one pour or can I do it in >several small >pours? I bought lead shot. Got an old can. Put it on a coalman stove and poured a little at a time untill it was all melted then let it cool. Getting the can off was fun. Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: Radio Controlled Clock Date: Wed, 14 Jan 1998 15:23:17 -0600 Charles, Thanks for the info! My only concern with the air loop antenna is the pickup of stray E field noise and how to use up a box of 12" ferrite rods. :) Jim Hannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Re: A Lunchpail Amateur Seismologists Best Story Date: Wed, 14 Jan 1998 14:24:34 -0700 Dewayne and Linda Hill wrote: > Hi Mereidth, > > Good to get your note last night and your natural earth resonant > rocker story was > quit good also. > > Well I just got back to the office from hardware store (another > $20 on the project.) > I pickup everything I need to rebuild the boom with the exception > of the coil and > magnet. I sent Larry an E-Mail about ordering his coil/magnet. > A: If your IBM mainframe computer magnet is truly a rare earth type of not.....keep it by all means....the larger the magnet, the more the flux....the more the emf....the more the signal...the less the amplification you may need. Rare earth magnets can range from 12K to 15K gauss. Alnico magnets...wide range, but they do a very good job also....uhh....perhaps 750 gauss. Larrys will be very effective I'am sure. Some of my best overall magnet and coil combos still (regardless of super rare earths) are the alnico type with relay coil or other shapes of coils (square). I don't know the gap of the IBM magnet, but consider using it with your coil....or even series of coils.....and another set of coils for eddy current damping if there is enough room. Check out the local surplus scene...over time....theres a world of coils out there! > After re-reading my description about the Lehman I can see how > you misunderstood > part of the write up. I boom is not at 37degs., the supenition > wire is at 37degs. > Hope you haven't trying to picture a 37deg boom all night. > A: Hey....first mistake I made in a whole 12 hours! ...Yes I thought you said you were going to put the boom at a 37 degree angle....not the suspension wire. > I bought 5lb. of lead. It looks like steel wool. How is the best > way to melt down? > Does the lead pour have to be made in one pour or can I do it in > several small > pours? > A: If it was me....and my past lead pouring experiences...I wouldn't even bother to melt it. Drill it if its one piece. You might consider putting it in a plastic container and also drilling a hole big enough for the boom,..with 2 side holes tapped for a screw to lock to the boom. Melted lead is very dangerious and time consuming to mess with. Drill a hole on top for your suspension wire attachment. If the container is too big for the lead, you might consider dropping in a bunch of those pesky pennys laying around....if it doesn't work out, you can always retrieve your investment......ahem! Watch out for the lead poisoning aspect...use gloves, and if you drill it as it is, paint over it afterward, well. Personally, I would get a bunch of pennys instead of lead for the mass...you don't lose or spend money, but you use it....as is. Well I have to get back to work. > Dewayne > > A: Although you are probably inpatient, try to make every pieceas well as you can....it may save repair time, down the seismic road. Above all, research everything possible and don't be afraid to change things around, if something may work better. Your's is a Lehman type....the main thing is too have fun with it.... Later...down the road...consider S-T's seismo...for its features. Regards, Meredith Lamb.....the unskilled lunchpail seismometrist _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: Radio Controlled Clock Date: Wed, 14 Jan 1998 14:52:48 -0800 Jim, If you really have "...a box of 12" ferrite rods", we could design it to use them, if you want to make them available to the group under some arrangement. At 12", a rod would be significantly smaller than a 12" square coil of wire. Charles Patton _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: A Lunchpail Amateur Seismologists Best Story Date: Wed, 14 Jan 1998 15:14:56 -0800 Meredith -- Very interesting story. I've been very curious if anyone has been able to "feel" a teleseismic event, and you did! Another curiosity this brings to mind is to make a "perpetual motion" machine -- a high-Q mechanism resonant at 6-seconds to pick up the background noise. The idea is to have this thing sitting there constantly moving. Perhaps a rocker with a strategically placed mass could be made into such a thing. I guess my best story is about going to Landers a few days after the big event and seeing boulders the size of a two-car garage that had tumbled down a hill, and seeing the almost 8-meter horizontal and 2.6-meter vertical offsets along the fault. There were ruptures everywhere on little fault strands going this way and that. I was standing about 5 meters away from the fault near the area of greatest offset when a M5+ aftershock occurred. I didn't feel anything, but heard a VERY low frequency rumble -- perhaps 15Hz and very loud. It sounded as though the nearby mountains were talking. I detected no movement of the fault and saw no dust, though. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: speaker force feedback devices Date: Wed, 14 Jan 1998 15:32:12 -0800 One quick point I'd like to make. Today's typical voice coil actuator in a hard disk drive memory has force constants in the 10 oz/amp with 10 to 20 ohm coils. This should be more than sufficient for the force balance equation until you get accelerations (from seismic activity) in the fraction of a G range which would be local strong motion, and the seismometer might have other problems at that point. The gaps on both sides of the coil are in the neighborhood of 0.010". The important thing is that if the coil is aligned flat in the plane of movement of the boom, you have almost an inch of movement available. The force won't be as flat as originally designed since the coil is designed to pivot around the bearing cartridge about 1 " away, but for small movements that would not enter the equation since a force balance design essentially holds the boom in a constant position, the assumption should be correct. I have seen crashed, removed from equipment, etc. drives for only a few dollars at surplus stores. At this point I hesitate to volunteer, but send me an email direct to my work address above if you're willing to pay for the postage/shipping on a magnet/voice coil assembly, and I'll see if the company is willing to donate junk drives from FA to the cause. If there's enough interest, I'll follow it up. Be aware of bureacratic red tape, as it will take awhile to get permission, if at all. In particular, I need Sean to verify my comment that 10 oz/amp is sufficient. Also one other comment for analysis, in high performance actuators, the L/R of the coil causes a pole in the response compromising the high frequency response, so all the actuator drivers use transconductance (current) amplifiers (as Karl was alluding to). This essentially removes the R from the equation. It only fails when the compliance range of the amplifier runs out such as when high acceleration is commanded and there is not enough head-room (the VCC supply) to achieve the current commanded. Sean's circuit is a voltage drive, so the L/R becomes a significant item. I don't want to criticize though, because it takes at least one more op-amp, and in our circuits, we use still another opamp and a sense resistor in series with the coil to measure the current (in this way we solve the stability problem of the negative impedance converter mentioned by Karl). But these circuits would add thermal drifts to the feedback, and so might not be worth the tradeoffs. But for the die-hard experimenter who wants to try and get a high resistance coil geophone unit working with force feedback, this might offer the path. Charles R. Patton _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: speaker force feedback devices Date: Wed, 14 Jan 1998 18:55:40 -0600 Charles R. Patton wrote: > > One quick point I'd like to make. Today's typical voice coil actuator in > a hard disk drive memory has force constants in the 10 oz/amp with 10 to > 20 ohm coils. This should be more than sufficient for the force > balance equation until you get accelerations (from seismic activity) in > the fraction of a G range which would be local strong motion, and the > seismometer might have other problems at that point. The gaps on both > sides of the coil are in the neighborhood of 0.010". The important > thing is that if the coil is aligned flat in the plane of movement of > the boom, you have almost an inch of movement available. The force > won't be as flat as originally designed since the coil is designed to > pivot around the bearing cartridge about 1 " away, but for small > movements that would not enter the equation since a force balance design > essentially holds the boom in a constant position, the assumption should > be correct. > > I have seen crashed, removed from equipment, etc. drives for only a few > dollars at surplus stores. At this point I hesitate to volunteer, but > send me an email direct to my work address above if you're willing to > pay for the postage/shipping on a magnet/voice coil assembly, and I'll > see if the company is willing to donate junk drives from FA to the > cause. If there's enough interest, I'll follow it up. Be aware of > bureacratic red tape, as it will take awhile to get permission, if at > all. > > In particular, I need Sean to verify my comment that 10 oz/amp is > sufficient. > > Charles R. Patton > > I did a quick calculation and if I did my metric conversions right Sean's speaker has a force constant of 45.5 OZ/AMP. This is not too far from the 10 oz/amp of the hard drive actuator. I don't quite have all the equations pluged into mathcad or I would give the numbers a try. I want to build a instrument with a slightly shorter boom so the hd actuators may work quite well for me. All Electronics http://wwwallcorp.com has some of the magnet assemblies in their catalog for $2.50 each. No coils though. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: Radio Controlled Clock Date: Wed, 14 Jan 1998 18:59:07 -0600 Charles R. Patton wrote: > > Jim, > If you really have "...a box of 12" ferrite rods", we could design it to > use them, if you want to make them available to the group under some > arrangement. At 12", a rod would be significantly smaller than a 12" > square coil of wire. > Charles Patton > Well maybe "a box" was an exageration. I went out to the shop and counted them. I have 9 not counting the one I already built into a WWVB antenna. I am willing to send them to whoever wants one for shipping ect. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: Radio Controlled Clock Date: Wed, 14 Jan 1998 17:29:39 -0800 Jim, I'd love to take you up on the "deal" how much do they weigh, and I'll send postage. Also I would need an address to send to! The longest rods I have are about 4" long so I was planning on a 9" or so square coil, so a 12" ferrite would be better. Thanks, Charles R. Patton work: patton@.......... 714-932-7476 home: patton@......... 909-698-9657 21490 Camino Arriba Murrieta, CA 92562 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: coils,FM,lead,etc Date: Wed, 14 Jan 1998 19:38:40 -0600 (CST) Charles,Darrel,Dewayne, Karl, Meredith, and co: Answering various topics: Regarding the disk drive actuator: if I calculated correctly, 10 oz/ amp is 283.75gm/A or 0.28375gm/ma * 9.806 (g) = 2.78 N/A (Newtons/Ampere), which is rather weak (~21%) compared with the 10" speaker (~13N/A). This design is probably a major compromise for the long stroke length and the clearance needed. I must again emphasize that the VBB feedback is NOT a VOLTAGE circuit, but a summation of characteristic CURRENTS through the force coil producing accelerations of the mass based on the information from the displacement transducer. It is fundamentally different from the traditional force=balance feedback. Regarding the inductance of the coil, one can include its' effect on the transfer function in the third and fourth order terms, but, as you observe, it will affect only the high frequency response. Regarding the BSSA article by Roberts: my copy here says Vol 79, No 4, pp 1607-1617, October 1989. Regarding FM telemetry: we use a VCO (voltage controlled oscillator) for every analog channel to create FM audio carriers on the standard IRIG (Inter Range Inter Government: set up for early rocket data telemetry) frequencies (680, 1020, 1360, 1700, 2040, 2380, 2720, 3060, etc, hz). They are multiplexed together, so we can send 8 to 10 channels over a narrowband (5khz wide) FM link and/or a phone line. We use a discriminator at the receiver/data collection end to recover the analog data; each discriminator has an input filter that "listens" to its particular carrier among the multiplexed audio, and then a PLL (phase locked loop) follows the frequency change of the carrier, and the lock voltage is the original analog data. Regarding melting lead: I agree with the cautions. Just pack the wool into a handy container, like a pill jar or whatever. Mass is mass. But prefer lead over brass, because the atmospheric buoyancy noise is inversely proportional to the density of the mass. Regarding feeling earthquakes: in the Aleutians, we could sometimes "predict" an event if we sensed the P waves. Since the events were all south of the islands, the time between P and S was usually 10 to 15 seconds. So if I felt a P wave while at dinner with the Navy personnel, I would say "I think we are about to have an earthquake", which is just about enough time for the S-wave to arrive and rattle everything. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: JHammes@......................... Subject: Re[2]: Radio Controlled Clock Date: Wed, 14 Jan 1998 17:51:44 -0800 Jim, I would like a couple, just let me know your address and the check is on it's way, thanks. Jerry Hammes Palo Alto ______________________________ Reply Separator _________________________________ Subject: Re: Radio Controlled Clock Author: PSN-L Mailing List at CCSMTP Date: 1/14/98 6:59 PM Charles R. Patton wrote: > > Jim, > If you really have "...a box of 12" ferrite rods", we could design it to > use them, if you want to make them available to the group under some > arrangement. At 12", a rod would be significantly smaller than a 12" > square coil of wire. > Charles Patton > Well maybe "a box" was an exageration. I went out to the shop and counted them. I have 9 not counting the one I already built into a WWVB antenna. I am willing to send them to whoever wants one for shipping ect. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: FM transmission Date: Wed, 14 Jan 1998 07:36:01 -0800 James Thanks for your assistance. I think you are correct about the license. I hope to do this in the very near future. I need to find out about tests-study mat'l etc. Thanks for the links. Barry James M Hannon wrote: > > Barry, > Directly FM modulating a radio carrier with the low frequency seismic > signals is not a good idea. There are all sorts of problems with the > receiver and transmitter design that would cause this to be very > unsatisfactory. Most of these problems are solved by modulating the radio > carrier with an audio frequency signal that is itself fm modulated by the > seismic signal. > > I am not sure what you are referring to about what is or is not allowed by > the FCC but: If you are not already a licensed Amateur radio operator you > might want to consider getting at least the no code amateur radio operators > license. This license will allow you to operate all sorts of radio > transmitters and transmit digital data or analog seismic signals. You do > have to pass a written test but it is not too hard after reading through > the license book a couple of times. http://www.arrl.org is a good place to > start for information. Also http://www.tapr.org is group involved in > digital radio communications. > > Jim Hannon > WB0TXL > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: Radio Controlled Clock Date: Wed, 14 Jan 1998 09:28:00 -0800 Charles I'm not to familiar with radio waves/antennas but I just read an article from Joe Carr in Nuts & Volts about antennas( specifically WWVB. Have you seen the article? In one design he uses a loop of ribbon cable. Do you think one of these antennas would work with the chip? Barry Charles R. Patton wrote: > > I just revisited the spec sheets on the Temic site which you can reach with: > http://www.temic.de/cgi/prod_head.tcl?headline=Radio-Controlled+Clock+Receivers+ICs&parent=abroadc&ueber=Communication+Ics > > The four parts available from Temic are: > Part Function Key Features Package > T4225B Receiver for 40 to 80 kHz Extreme low power consumption Die > U4223B Receiver for 40 to 80 kHz 4-bit ADC output SSO20 > U4224B Receiver for 40 to 80 kHz Extreme low power consumption SO16L > U4226B Receiver for 40 to 80 kHz Extreme low power consumption SSO20 > > Since I have no intention of doing high production, chip-on-board, the T4225B is dismissed. > > > They basically are very simple to use. They require 3 non-electrolytic caps, 1 resistor, 1 tuned antenna, and 1 or 2 60.00KH z crystals. They use a maximum of 25 uA at 5 V while operating, but the output is guaranteed for 3 to 4 uA only, which is why I commented about buffering the output for most uses. > > I want to expand on my comment about the antenna. One simplistic way of viewing a ferrite antenna is that its length is its important dimension and if you have a loop whose side is that length, they become comparable. Since ferrite rods used in the c urrent radio controlled clocks on the market are only about 3" or 4" long, then a loop antenna the size of your hand, can easil y best them. And that way you don't get involved in the temperature curves of the ferrite, or procurement difficulties. > > Hope this helps. > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: speaker force feedback devices Date: Wed, 14 Jan 1998 09:36:44 -0800 Jim I took apart a harddrive about a month ago. What concerned me was the potential friction in the pivot. Do you think it may be to high? Barry Jim Hannon wrote: > > > > I did a quick calculation and if I did my metric conversions right > Sean's speaker has a force constant of 45.5 OZ/AMP. This is not too far > from the 10 oz/amp of the hard drive actuator. I don't quite have all > the equations pluged into mathcad or I would give the numbers a try. I > want to build a instrument with a slightly shorter boom so the hd > actuators may work quite well for me. All Electronics > http://wwwallcorp.com has some of the magnet assemblies in their catalog > for $2.50 each. No coils though. > -- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: Speaker coil-based seismos Date: Wed, 14 Jan 1998 09:56:25 -0800 Roger I centered the coil in a brass tube that was about 1/2" bigger in diameter than the coil. I then used 6 brass screws at 120 deg. apart oriented radially( 3 @ two locations along the length). I was not to difficult to center the coil. Sean Thomas's suggestion about using 50 mph tape to remove particles worked for me. I agree though one will need a sealed enclosure to keep future particles out. The epoxy is strong. A year ago I tried to separate the plates and broke the magnet. I think temperature will affect the magnetism so one may have to take care with temp. I am not sure what temp is ok. Barry Roger Baker wrote: > > Friends, > Upon investigating some of the idiosyncrasies of speaker coils as > sources of force for force feedback,(and this actuator looks like it might > be the best way to go for a whole bunch of related force feedback-related > instrument designs yet to come), it appears that one of the trickiest parts > is getting the coil properly recentered whenever the coil is removed and > remounted. An intact paper speaker cone absorbs seismic energy. The > cylindrical coil is precision made and needs to be carefully protected > against deformation from its normal circular shape. > > The speaker manufacturers are clearly skilled at making sure the axis of > travel of the cylindrical coil coincides exactly with the annular magnet > gap, since the clearance is only a few thousandths of an inch. Therefore > remounting the coil on a beam is likely to cause the moving coil to rub > against the gap somewhere, in my experience. This problem may be worse with > smaller speakers. > > Also, the bare gap strongly attracts stray particles of iron which are hard > to see, hard to get out, and probably cause killer friction if they remain. > > Speaker magnets are usually made of an top iron plate with a hole and > epoxied to a black ceramic magnet donut. Then an iron backplate with a > stout cylindrical iron pole protruding from the center is epoxied to the > back of the donut so the pole sticks up through the hole, creating a narrow > annular magnetic gap. It is useful to know how to enlarge this gap > slightly, with a slight loss in electromechanical efficiency. This does not > eliminate the necessity of being able to make fine adjustments to make sure > that the coil is exactly centered with respect to the magnet gap. > > If we disassemble the magnet, we can enlarge the hole in the top plate > slightly with a dowel or drill bit wrapped with carbide paper, file down > the center pole a little too, and then glue everything back together. > > This may be done by softening the epoxy by slowly heating the magnet in a > frying pan over a low flame. Wedge a sharp point in the gap of the hot > magnet, (probably about the boiling point of water or a little hotter) and > one of the iron plates should pop loose. Then we can let everything cool, > clean the surfaces, enlarge the gap slightly, and epoxy everything back in > place. Because the gap spacing is unstable due to magnetic force, we need > to carefully shim the gap to keep it even in width, perhaps with a ring of > sheet metal or paper wound around the center pole or some such spacer while > the new epoxy sets up. > > --Yours, Roger > > _____________________________________________________________________ > > 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: speaker force feedback devices Date: Wed, 14 Jan 1998 10:18:07 -0800 Jim Another source for magnets might be Dowling Miner Magnetics Corp. in Sonoma Calif. I got one of their catalogues a while back. They have several different geometries and materials but they ain't cheap. Barry Jim Hannon wrote: > .... All Electronics > http://wwwallcorp.com has some of the magnet assemblies in their catalog > for $2.50 each. No coils though. > -- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: zero length spring Date: Wed, 14 Jan 1998 23:31:15 -0600 (CST) Walt, Regarding "zero length" beahvior of a spring. For an ordinary spring, as it it stretched, the change in length is proportional to the force applied. If you attach a linear dial an put it in a box and step on it, it will tell you how well you prospered fron the holiday feasting. ie Hooks law: F = k *(l - lo), where k is the spring constant (force/unit length), l is the length with the force F applied, and lo is the initial length. When such a spring is used in a vertical seismometer, this means that the restoring force changes as the boom moves, making the sensor non-linear. This was solved in the 30s by the LaCoste suspension that devised a spring such that at a specific length the change in force with change in length became zero. That is, if lo = 0, so F = k*l, then F is constant. So any minute acceleration will move the mass in a linear fashion. So when such a spring is made, namely by twisting the wire (or quartz fiber in gravimeters) as the coil is wound, the spring ends up forcibly closed: it takes an initial force to open it. I won't go into the math to determine the constants, but at some opened length, lo becomes 0. With the leaf spring I use, this occurs at about a 5" opening, and is evident when the spring is installed and the opening adjusted. At one point, the boom will not stay balanced, but floats either up or down with instability (aka an infinite period). So I increase the opening slightly, and the period becomes stable. A stable period is essential for a well defined transfer function. Regards, Sean-Thomas !p _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: Speaker coil-based seismos Date: Wed, 14 Jan 1998 23:39:26 -0600 (CST) Barry and Roger, The speaker I use has the magnet assembly both glued and riveted together. As tempting it is to increase the clearance for the coil, it will definitely reduce the force constant. I generally have little trouble aligning the coil, but I have had problems with stray dog hairs falling in. If I were to try to improve the speaker application, I would try to wind a single layer coil in place of the two layer coil, on an inside former with more clearance. As it is, it works fine. Also, significantly heating the magnet, or even removing the steel pole plates, will probably weaken it. I suspect that the magnet is charged (magnetized) after it is assembled, as we do when making magnets for large seismometers. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roger Baker Subject: Re: Speaker coil-based seismos Date: Thu, 15 Jan 1998 03:24:00 -0600 At 11:39 PM 1/14/98 -0600, you wrote: >Barry and Roger, >The speaker I use has the magnet assembly both glued and riveted >together. As tempting it is to increase the clearance for the coil, >it will definitely reduce the force constant. I generally have >little trouble aligning the coil, but I have had problems with >stray dog hairs falling in. If I were to try to improve the >speaker application, I would try to wind a single layer coil in >place of the two layer coil, on an inside former with more >clearance. As it is, it works fine. > >Also, significantly heating the magnet, or even removing the >steel pole plates, will probably weaken it. I suspect that >the magnet is charged (magnetized) after it is assembled, as >we do when making magnets for large seismometers. > >Regards, >Sean-Thomas Dear Sean-Thomas, et al, Actually, the reason I posted the piece on diassembling speaker magnets by heating them is that I am currently experimenting with a small Sanyo speaker that only weighs 45 grams, has a coil resistance of 32 ohms. The coil gap was only 20 thousandths of an inch total, most of which was occupied with the coil. Its a tight fit. I'm experiimenting on an unusually small scale primarily to learn about the physics of different mass suspensions and circuit behavior without the inconvenience of building a large instrument, and because such a scale is more compatable for possible eventual adoption with my existing temperature feedback control and hermetic enclosure abilities (for the latter I have the cut off top of a gallon jug as a bell jar and a glass plate for a base. This arrangement can hold a slight vacuum for at least a week I have found.) I am currently using my own miniature leaf spring arrangement to support about a five gram mass and the feedback coil. (My other leading contender for this purpose is to use a magnetic spring and knife edge pivot combination). Anyhow, I had great difficulty with my coil clearance adjustments with the current arrangement until I widened the annular gap to perhaps 40 thousandths. Loudspeakers have just the right design properties to move masses of various sizes fast. Bottom line: I suspect small force feedback instruments based on small speakers may have their own role to play in amateur seismology. Thats the kind of stuff I love to find out for myself. At any rate, the magnet surgery was successful and widened the gap so the coil no longer binds with the suspension I am using and the magnet does not seem to have suffered much in observable properties. I vaguely recall that the Curie point of ceramic magnets might be about 300 C, and if one always stays below the Curie point for the particular ceramic magnet composition in question, the strength of the magnet should not suffer much, I think. Some of the larger speakers I saw at Radio Shack seem to have an almost identical construction and I see no reason why it should not be possible to widen the gaps of many larger speaker magnets as needed, and if needed (once you peel off the iron frame, the magnet looks kind of like an iron hockey puck with a black rim, and the latter is what you heat). As usual, I am using a light beam as my displacement sensor, and as things now stand there is plenty of feedback power to keep the mass oscillating at a frequency that depends greatly on the exact characteristics of the feedback circuit. I'm using a small twelve volt lead acid battery for power. I like to design with 324 quad op amps, and they put out 20-40 millamps of current (depending on whether you're sourcing or sinking your current). If needed, you can parallel several of them configured as voltage followers through 10 ohm load sharing resistors to drive the coil directly without any power transistor stage. If the feedback force exerted on the spring and mass is weak, the oscillation frequency is slow (the natural period of the mass and coil and spring assembly without the coil connected up to restore the position of the mass is even lower of course). As the gain is turned up, the speaker magnet acts like a stiffer and stiffer spring that tries to restore the position of the mass and the oscillation period decreases accordingly. Despite widening the gap, which obviously must weaken the magnetic force somewhat, there's plenty of force left for my purposes. Of course the ultimate goal is to rapidly damp the oscillations that result from a sudden displacement and end up with the fastest most stable and linear response. As with much of life, there are many practical ways to get fair results and a few ways to get optimum results. Suffice to say I'm having fun playing with various components on a plug-in circuit board and learning how the electronics interacts with the mechanics. --Yours, Roger _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RLLaney Subject: Re: A Lunchpail Amateur Seismologists Best Story Date: Thu, 15 Jan 1998 10:35:29 EST Saw the comments on melting down lead wool, etc. Sounds like the hard way. At plumbing shop I was able to get 5 pound hunks of lead about 4 inches in diameter and about 2 inches thick. Simply drilled a hole in the center and slipped onto the Lehman boom. They also make nice sized weights for making sure the instruments and coils have good contact with the floor. I would assume that lead in this form would be common elsewhere. For what it's worth. Bob Laney Herndon, VA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Northern CA/NV Quake Date: Thu, 15 Jan 1998 07:41:20 -0700 We just had a small temblor up here along the Northern California/Nevada border region. Measured ~M3.8 and was centered 10 miles N of Truckee near Sierraville. Widely felt, from Truckee and Tahoe Donner to Quincy. -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Larry P. Thomas WA0GWA" Subject: VBB feedback Current vs Voltage Date: Thu, 15 Jan 1998 10:05:10 -0600 I've been following this SIG for some time but been too busy to really contribute much. There seems to be a difficulty understanding that the currents sum in the force coil on the VBB system. I thought I'd offer an alternate explanation. Due to the very very low impedance of the coil (mostly resitive athe frequencies of interest) when compared to the impedance of any other component connected to the ungrounded side of the coil we can really consider it to be a virtual ground, much like the input to a high gain operational amplifier. In other words, changes in current from one leg feeding the coil have almost no effect on any other leg feeding the coil because no significant voltage change is caused by this current. The coil is simply a non-ideal (but almost) current summing junction. Just as in a good operational amplifer with high gain where any output possible from the opamp can be obtained with virtually zero input voltage making the input a current summing node, the coil can produce the required force with virtually no applied voltage. Force is a function of the current in coil and not the volatage across it. I hope to make this VBB design my first actual sensor. I really enjoy this SIG and want to thank those that contribute Later Larry Thomas >I must again emphasize that the VBB feedback is NOT a VOLTAGE >circuit, but a summation of characteristic CURRENTS through >the force coil producing accelerations of the mass based on the >information from the displacement transducer. It is fundamentally >different from the traditional force=balance feedback. >Regarding the inductance of the coil, one can include its' effect >on the transfer function in the third and fourth order terms, but, >as you observe, it will affect only the high frequency response. ----------------------------------------------------------------------- Larry P. Thomas wa0gwa voice : 1 913 888-0282 Krell Technologies fax : 1 913 782-9359 8960 Bond pager : 1 816 989-HELP Overland Park, KS www : http://www.krell.com 66214-1764 e-mail : mailto://lpthomas@................ ----------------------------------------------------------------------- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Fell Subject: Re: Purchasing Seismograph -Reply Date: Thu, 15 Jan 1998 16:20:29 +0000 Thanks for the advice, second hand but no less helpfull. John _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: STM-8 spring opening determines construction? Date: Thu, 15 Jan 1998 10:13:32 -0700 S-T Morrissey wrote: > Walt, > > Regarding "zero length" beahvior of a spring. > > For an ordinary spring, as it it stretched, the change in length > is proportional to the force applied. If you attach a linear dial > an put it in a box and step on it, it will tell you how well you > prospered fron the holiday feasting. ie Hooks law: F = k *(l - lo), > where k is the spring constant (force/unit length), l is the length > with the force F applied, and lo is the initial length. > > When such a spring is used in a vertical seismometer, this means > that the restoring force changes as the boom moves, making the > sensor non-linear. This was solved in the 30s by the LaCoste > suspension that devised a spring such that at a specific length > the change in force with change in length became zero. That is, > if lo = 0, so F = k*l, then F is constant. So any minute > acceleration will move the mass in a linear fashion. > > So when such a spring is made, namely by twisting the wire > (or quartz fiber in gravimeters) as the coil is wound, the spring > ends up forcibly closed: it takes an initial force to open it. > I won't go into the math to determine the constants, but at some > opened length, lo becomes 0. > > With the leaf spring I use, this occurs at about a 5" opening, and > is evident when the spring is installed and the opening adjusted. > At one point, the boom will not stay balanced, but floats either > up or down with instability (aka an infinite period). So I increase > the opening slightly, and the period becomes stable. A stable > period is essential for a well defined transfer function. > > Regards, > Sean-Thomas > Sean-Thomas, If I interpret the last paragraph right, then all reproseismo's should be constructed pretty much based on the ~ 5" opening of the spring. I.e......boom height and everything else must follow a accomodating distance based on the preferential transfer function of the spring. Any other type of construction must somehow find adjustable ways of achieveing this rough 5" opening. (?) Regards, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Potpourri: Re: VBB fdbk, lead weights, VLF loop ants Date: Thu, 15 Jan 1998 10:41:17 -0800 VBB feedback: Larry P. Thomas explained my point very well. The coil in Sean's circuit is being used as a virtual summing node. So as long as its resistance is low in relation to the other components' resistance and reactance, the feedback coil's resistance doesn't matter much and it is current driven. But as that resistance rises, the virtual ground statement no longer holds and the other term in the equation reflects this change. That can be fixed by using opamps which can provide the virtual ground and force the current independent of the coil's resistance. As a practical question -- how far does the boom physically swing up and down in the VBB design while force feedback is in operation? By design of the feedback sensor, total travel can only be about +- 1 mm. If so, then the long throw of a voice coil in a speaker really doesn't matter. For instance the use of the hard drive actuator coil with approximately 5:1 less force/amp says you could just rescale the output components C, Rp and Ri. The problem then starts to be the large values of C (approx. 120 uF) and low value of Ri (approx. 21 K) so that you might have to add one high current output opamp to be the virtual summer and capable of driving the weaker actuator coil structure. Barry Lotz wrote: >What concerned me was the potential friction in the pivot. I think there is a bit of a misunderstanding here. I agree the pivot bearing in a drive would not be at all suitable for the pivot on the seismometer. Sean's crossed hinge is much better. What I was thinking (you know the old saying, "Do what I think, not what I say!") is to cut the voice coil off of the drive actuator and glue it to the end of the boom and use it instead of the speaker force feedback coil system. The magnet structure of the drive would be mounted in a vertical sense so the coil could go up and down with the boom (for a vertical seismometer) or horizontal for a Lehman style. The force would be more non-linear over the stroke of an 1" or so, because the curvature of the magnet structure is designed for the radius to the pivot bearing in a drive (approx. 1" instead of the boom length of about 24"). But in a stroke of 1 mm or so, this should be insignificant. Roger mentioned that the speaker coil has a gap of 0.020" or so, This is about the same for the actuator. However several things are in your favor: 1) the geometry of the boom to gap using the actuator magnet does not imply any change in the gap, since the gap is parallel to the swing and 2) if you want more gap, the actuator magnet structure is very easy to shim open more as it is just held together magnetically (at least it is in our product.) If you do that, I would strongly suggest using magnetic materials for the shimming, to minimize the field strength loss. 3) Shimming an actuator has much less effect than it does to a speaker because the gap the coil is in is already much larger than in the speaker, so the proportional change is much less. So in conclusion, it should be a much more forgiving structure to use in a force feedback seismometer using beams. LEAD WEIGHTS: 5 pound (?) lead bricks are available in home building supply stores as the weights for "Bull" floats. (A "Bull" float is the large flat bladed tool used to finish off the surface of wet cement floors after they have been poured.) This was the cheapest lead I could find easily when I needed some for ladder counterweight I poured. LOOP ANT: Barry Lotz wrote: "...In one design he uses a loop of ribbon cable. Do you think one of these > antennas would work with the chip? The Temic spec sheet says the antenna must have a minimum of 1.5 uV and a minimum Q of 30. I haven't read the Nuts and Volts article, but using ribbon cable for a loop strikes me as a bunch of hassle to solder the wires together. Various construction techniques I've seen over the years have used pipe through which they pulled a bunch of wire and then soldered them into one continuous loop. Instead my thought on this process would be to take PVC pipe and make into a square of the size you want using standard ell joint couplers (or if you want a round shape, use sweep ells, but you'll be limited to certain sizes). After the glue sets up, grind the outside perimeter of the pipe all the way through to expose the inside all the way around. Wind your coil in this "hula hoop". Once you have the number of turns you want, obtain a roll of aluminum foil duct tape (couple of $ for a small roll 3" wide.) Run this over the whole length, but stopping with a gap so you don't form a shorted turn. Now you have an electrostatic shield you can ground to your feed cable shield and the perimeter gap has been sealed with a weatherproof, ozone proof covering of aluminum. Haven't done it yet, but this is the method I was going to use for the Temic chip when I breadboard it. so wait a while if you want, and I'll let you know how it works out! Charles R. Patton patton@......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Rockland filter Date: Thu, 15 Jan 1998 14:46:41 -0500 Dewayne, I have no manual for the Rockland filter. I posted all the info that I= have. I'm aware of the places which sell manuals but haven't tried them.= = If you get one, let me know. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Re: A Lunchpail Amateur Seismologists Best Story Date: Thu, 15 Jan 1998 14:46:43 -0500 Norman Davis, Lead can be cast in a wood mold. I use a router bit in a drill press t= o cut a cavity in any wood, even pine. You get some smoke when the lead is= poured in but the cavity can be used many times. In fact, the first casting may have some bubbles from the water in the wood but this gets better as the wood chars. For my Lehman weight, I made 4 slabs about 3/= 8" thick and then soldered them together using sticks of lead and a Bernzomatic torch. Sticks of lead can be made by placing an aluminum angle standing on its= point and casting lead in the groove. It is best to do a lead casting in one pour. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Re: FM transmission Date: Thu, 15 Jan 1998 14:46:45 -0500 Jim Hannon, Amateur radio transmissions require that the station ID be given at lea= st every 10 mins. This might be a major complication in transmitting continuous seismic data. Bob Barns KB2IKC _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Radio Shack's Radio Controlled Clock Date: Thu, 15 Jan 1998 14:46:48 -0500 Larry, = Fascinating stuff about the Radio Shack clock! Thanks. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Subject: Re: FM transmission Date: Thu, 15 Jan 1998 14:31:02 -0600 (CST) On Thu, 15 Jan 1998, Robert L Barns wrote: > Jim Hannon, > Amateur radio transmissions require that the station ID be given at least > every 10 mins. This might be a major complication in transmitting > continuous seismic data. > Bob Barns > Bob, I am aware of the ID requirements and I guess I did not think it would be a big problem. If you are using the fm audio subcariers you could include a subcarrier that was modulated with the ID continuously. If you are sending digital data you could send and ID in between data packets every so often. Jim Hannon WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Re: FM transmission Date: Thu, 15 Jan 1998 12:35:37 -0800 At 02:46 PM 1/15/98 -0500, you wrote: >Jim Hannon, > Amateur radio transmissions require that the station ID be given at least >every 10 mins. This might be a major complication in transmitting >continuous seismic data. >Bob Barns >KB2IKC > Also there is the thing about broadcasting. Don't know how the FCC would like that. There has been some talk about encodeing quake data into the APRS system Amature Possiton Reporting System. It would plot the quake on a map. I am not a hacker when it comes to that stuff but you would need a latlong embedded into a packet beacon string and then everyone could see it on the map. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: zero length spring Date: Thu, 15 Jan 1998 13:47:22 -0800 Check out the URL: http://www.lacosteromberg.com/detail.html#physics The site is LaCoste-Romberg Co. and the particular URL is pointing at a section of their manual which describes the theory and construction of the zero-length spring and LaCost suspension in a gravity meter. Back up a bit, and you can get a full education on gravity meters they manufacture. I'm amazed. This is the first site I have come across that puts their equipment manuals on line. Charles R. Patton patton@......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: VBB CURRENTS Date: Thu, 15 Jan 1998 16:37:51 -0600 (CST) Charles, I must again emphasize that in the triple feedback VBB configuration the CURRENTS that flow through the force coil are controlled by the actual reactances of the three feedback elements, whose input is either the displacement voltage or the integral of it. These ARE NOT filters; they actually convert the mass displacement voltage into the characteristic current that shapes the acceleration response of their respective portion of the response curve. There can be NO amplifier or other device between the summing junction of Rp, Cp, and RI and the force coil, since this would prevent these currents from flowing. There is in fact NO VOLTAGE to amplify. The transfer function actually describes an assembly of equations of accelerations that are produced by each characterisstic feedback path. This acceleration response is converted to the flat velocity response by multiplying through by omega. Another important point to notice is that the VBB output voltage is obtained from the displacement transducer output, which BECOMES the VBB output WHEN and ONLY when the triple feedback is functioning. THis is a unique feature of this VBB circuit. Turn off the feedback, as when the boom needs to be recentered, and the output is that of an undamped mechanical sensor swinging freely at To. Re-connect the feedback, and the seismometer output immediately recovers as a VBB sensor with a period of Tn . Also notice that the output still contains the DC displacement information, which is reduced (by the current feedback parameters) by about a factor of ten. ie if the VBB output indicates 5 volts, and r=500mv/micron, the mass offset is 10 microns with the feedback on, but will shift to 100 microns if I disconnect the feedback. Also, if 5 volts is the limit of the displacement amplifier output, it is also the limit of the feedback DC operating range, in this case, +- 100 microns. (NOT to be confused with the dynamic range of the velocity output) Other force balance feedback configuations obtain a voltage function of acceleration across the force coil. This is not the case here. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: A Lunchpail Amateur Seismologists Best Story Date: Thu, 15 Jan 1998 15:01:45 -0800 Thought I'd add my $.02 about melting lead: I bought one-pound ingots and melted them with a home-shop type (Berzomatic) propane torch. I made a mold out of brass sheet, soldered together. I held the ingot over the mold with a pair of pliers and melted the lead a drop at a time, playing the torch on the ingot. Each drop would solidify in the mold after a couple of seconds. This avoided the danger of pouring a quantity of molten lead, and the mold never even got hot enough to melt the solder holding it together. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: spring opening Date: Thu, 15 Jan 1998 17:03:24 -0600 (CST) Merdith, THat is the case (5.5") for that particular spring. I have been wanting to try something about half the size, with an 8" boom, if I can get the coil to move freely in the magnet. BTW: the coil clearance of the 10" dual-coil RS speaker is about 0.005 all the way around. I use a thin strip of 0.005" plastic to check the gap to make sure it is symetrical when I install the magnet. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: W6JRF Subject: Re: A Lunchpail Amateur Seismologists Best Story Date: Thu, 15 Jan 1998 18:15:44 EST Two more cents for the melting lead story. Be absolutely certain the mold that is to receive the molten lead is dry. If you pour the lead into a confined mold and there is any moisture in it, you will find that you made a miniature volcano powered by steam! I know, I've been there and done that. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: FM transmission Date: Thu, 15 Jan 1998 18:27:46 -0600 Norman Davis WB6SHI wrote: > > > Also there is the thing about broadcasting. Don't know how the FCC would > like that. > There has been some talk about encodeing quake data into the APRS system > Amature Possiton Reporting System. It would plot the quake on a map. I am > not a hacker when it comes to that stuff but you would need a latlong > embedded into a packet beacon string and then everyone could see it on the > map. > > _ -- Norman, Just to be sure I went and back and read the FCC rules again. 1: Telemetry is specifically permitted by the rules. 2: Broadcasting is transmitting to nonamateurs or transmitting without a specific recipient. Since in this case one would be transmitting to yourself a licensed amateur it would not be broadcasting. There are some rules about control of an unattened transmitter but there are ways of meeting those requirements. Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: spring opening Date: Thu, 15 Jan 1998 07:02:39 -0800 All I had success with this option also. I used a short piece of large diameter shrink tubing that I cut longitudinally. After I secured the coil I removed the plastic. Barry S-T Morrissey wrote: > > BTW: the coil clearance of the 10" dual-coil RS speaker is about > 0.005 all the way around. I use a thin strip of 0.005" plastic > to check the gap to make sure it is symetrical when I install > the magnet. > > Regards, > Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ted Blank Subject: Re: CIODAS08JR & EMON Date: Thu, 15 Jan 1998 17:56:47 -0800 (PST) Hi Francesco, If I understand you correctly, you are not seeing any data trace (line)=20 on the screen, right? When this happens to me, it is usually a mistake in the values for=20 ADCValueAtMinVolts, ADCValueAtMaxVolts or ADCValueAtZeroVolts. =20 Here is what to do. Start EMON and then press F2. This will start=20 showing the actual sample value (a number) in the upper left corner of=20 the screen. If this value stays near zero, then your A/D board range=20 should be Max=3D2047, Zero=3D0 and Min=3D-2048. If the value you see sta= ys=20 near 2048, then your A/D board range should be Max=3D4095, Zero=3D2048 an= d=20 Min=3D0. =20 Please try the F2 and tell us what numbers you see. Also, have someone=20 jump up and down near the sensor and tell us what the highest and lowest=20 number you see. Regards, Ted >=20 > I checked the channel viewing: it's 0 and ok. > The other possible channels are not installed and so the set in .opt fi= le > at line address 2^, 3^ ch. is 0. > So, I'm using the 0 ch. and in pin connector i've choosed: pin n=B0 1 f= or > input analog(positive) and pin 20 for ground. Is it right? > If the connector from sensor is disabled from female board conn. the si= gnal > is a blank continuos line. When i connect the sensor that line disappea= r. > Why?????? > At last: in .opt file there is an option about ADC values. But the choo= se > in the 3 option where is? > Graciously > Francesco >=20 >=20 > At 06.40 13/01/98 -0800, you wrote: > >Francesco > > Check which channel you are monitoring (F7 on my version) and make > >sure you have the correct entries for the other two of the three > >possible channels in the .OPT file.=20 > > Barry > > > >Francesco wrote: > >>=20 > >> Thank very much Bob, Ted and Jim. > >>=20 > >> The I/O address it's ok and the board seems to function evenly. > >> But I believe to have any other problem. > >> If are not there events, must I see any trace in the screen or no? > >> I see that the program runs, but I don't see any trace and no file i= s > >> saved. Is that regular? > >> These is the setting values: > >> noise zones =3D 1% > >> convert per sample =3D 25 > >> buffers =3D 4000 > > > >_____________________________________________________________________ > > > >Public Seismic Network Mailing List (PSN-L) > > > >To leave this list email listserver@............. with the body of the= =20 > >message: leave PSN-L > > > > > FRANCESCO NUCERA > OSIMO - Ancona - > ITALY >=20 > Lat. 43 29" E - Long. 13 29" E >=20 >=20 > _____________________________________________________________________ >=20 > Public Seismic Network Mailing List (PSN-L) >=20 > To leave this list email listserver@............. with the body of the=20 > message: leave PSN-L >=20 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: FM transmission Date: Thu, 15 Jan 1998 07:07:53 -0800 Jim My thought was to acquire a number of quakes by a proper trigger routine and then transmit the data when the remote memory filled up (flash card preferably) or when the data was requested. This way there shouldn't be continuous transmitting. Barry >Jim Hannon wrote: > Just to be sure I went and back and read the FCC rules again. 1: > Telemetry is specifically permitted by the rules. 2: Broadcasting is > transmitting to nonamateurs or transmitting without a specific > recipient. Since in this case one would be transmitting to yourself a > licensed amateur it would not be broadcasting. There are some rules > about control of an unattened transmitter but there are ways of meeting > those requirements. > > Jim Hannon > http://soli.inav.net/~jmhannon/ > 42,11.90N 91,39.26W > WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Bob Thomasson <102073.3346@..............> Subject: Northern CA/NV Quake Date: Thu, 15 Jan 1998 23:10:36 -0500 <>= Charles, I felt it right here too - about a half mile N of the NDF fire station on= Mt Rose Hwy. A single abrupt jolt that also made the house creak, at 0703 on my watc= h. = Bob Thomasson _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Lengthing Period Date: Thu, 15 Jan 1998 09:46:29 -0800 Sean Thomas et al I have a vertical pendulum that I am configuring as a VBB horizontal sensor. It has an approx. length of 8" with a period of 0.9-1.0 sec. I am trying to increase the period without increasing the mass. I have put additional weight at the pivot point at the same elevation as the pivot thus increasing the moment of inertia but I believe not increasing the mass in the horizontal plane, increasing the period to 1.35 sec. Do you think there is a way to increase the period by the use of flat springs, geometry etc rather than weight? I would like to keep the sensor under 12" tall. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Seismic Surplus Scene And The Holy Grail Date: Thu, 15 Jan 1998 22:40:56 -0700 It used to be...(oh NO; not another story), that back in the 1960's it was a feast of sorts or mostly famine for surplus stuff. Good stuff like working chart recorders where a premium thing and you NEVER saw them in surplus stores. Trinkets like round plexiglass tubes of maybe 8" diameter (drums) were around here, as were alot of nice rolls of various sizes of enameled copper wire, as were lead ingot piles, precision rods of steel and all manner of juicy thick aluminum plates. Nowadays this stuff doesn't seem as readily available...or so it seems. Military surplus stores sometimes carried objects of interest. Electronic surplus stores were the prime bug eyed places to hit every so often...you never know...was the primary high anticipation motive, to visit them frequently. Hitting the stores on weekends was akin to the excitement of a new discovery. Sometimes you find "gold" and you could salt it away for that big combination that yields something of value...but mostly it was; and still is....a piece meal quest. Dunno...but...I think that if you're limited to just surplus stores, you may be depriving yourself of what I seem to think maybe a worthwhile source...the local metal junkyard (metal & salvage boutique). One old source (in the 1960's, not now) in the Denver area frequently bought all manner of metal and scrapped and sorted it out in piles. (I suppose most of them do this) Anyway...I LOVED this place...piles of electronic cards, occasional chart recorders of military voltages (24vac 3 phase), unopened government boxes with mystical writing on them which tempted me to inspect the innards every time. Once they had huge racks of strip chart recorders, but alas...they wanted a ransom for each ($100.00), well...they instead later scrapped them apart. To help you salivate more, they once had about six barrels of the 52 gallon variety, filled to the brim with big solid one piece alnico magnets, which they would sell for $6.00 each. Temping, but I already had magnets. WHEEEE EUREKA! Uhhh....maybe limited piece meal....but when you're starving! Anyway that was 30 odd years ago. So, check out your local or not so local boutique, which some of you do anyway. Nowadays the electronic surplus scene presents a continual reminder of the 60's it seems..same old, same old. Chart recorders?...yea the old clunkers are around...now...like Texas Instrument Rectiwriters or Esterline-Angus pen motor jobs. These are good for magnets...but the imprecision is HORRIBLE, and even if you can approach making them work, and the paper can be found, and the ink, and the replacement parts, or jerry rigged repairs and etc., etc. UGGHHHHH! This is alright for me to say, as I'am a senior drummer. Ahem! This is not to say you can't find stuff that works, you can, you just have to be in the right place at the right time. Overall though, (for me), the electronics surplus stores still need to have their periodic inspection....and it is still a long time between finding something REALLY worthwhile. If you're a true blue lunchbucket seismometrist you do this stuff....the thin wallet and the code of the west thing. Coyote in the desert. YEA.....I know...the computer age is here. Actually its looking better all the time...especially since this computer and its infamous GPF's seem to have disappeared over the last week or so. This gives me pause to consider that aspect more and more. The initial outlay is relatively large but...it may work consistently, which my chart recorders don't do (drummers delight). Well....I'll have to have a spam sandwich and think alittle more about that. The future perpetuation of the seismic scene addiction is probably here already. Too me...this STM-8 stuff is coming on strong...and the juicy piece meal aspect involved that does not depend on discovering the gold in the surplus mines. Somehow I'am feeling more rejuvinated, and can even manage to get my socks on in the morning...eventually...after turning on the home computer...however coffee is 2nd in line. Sooooo....what am I telling you this for... I guess because the past is still the present....the holy grail thing....otherwise you wouldn't read this at all. (Is there a hidden message here....or something??... :>) Thanks, Meredith Lamb.....the lunchbucket seismometrist unDictionary meaning of: seimometrist: One who continually seeks the perfect combination of cheap reliable seismograph, but who may show frequent quirks from the as yet unsucessful quest for the holy grail. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: The Colorado Springs Meteorite Date: Fri, 16 Jan 1998 07:41:38 -0700 Todays Denver Post newspaper had an update on the meteor of last Sunday. Actually it states that the likely impact area (if any), may be closer to the town of Elbert, Colorado which is maybe 25 miles north east of Colorado Springs. Triangulation efforts continue from witnesses. Any effort to find fragments may not be fruitful till spring. A guesstimate of total fragment weight may range upward to 60 pounds. The meteor came in from the southwest, brilliant white to blue, multiple booms heard, breakup in flight into 2 or 3 pieces and then it winked out. Earlier witnesses mentioned house vibrations before the booms were heard. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: The Colorado Springs Meteorite Date: Fri, 16 Jan 1998 13:56:11 -0700 (MST) On Fri, 16 Jan 1998, meredith lamb wrote: > Todays Denver Post newspaper had an update on the meteor > of last Sunday. Actually it states that the likely impact area > (if any), may be closer to the town of Elbert, Colorado which > is maybe 25 miles north east of Colorado Springs. Triangulation > efforts continue from witnesses. Any effort to find fragments > may not be fruitful till spring. A guesstimate of total fragment > weight may range upward to 60 pounds. > The meteor came in from the southwest, brilliant white to > blue, multiple booms heard, breakup in flight into 2 or 3 pieces > and then it winked out. Earlier witnesses mentioned house > vibrations before the booms were heard. That is funny, because I saw a spectacular meteorite falling Sunday night in the NE sky here is Mesa AZ. Is it possible that this could be the same one??? ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Francesco Subject: Re: CIODAS08JR & EMON Date: Fri, 16 Jan 1998 13:30:16 +0100 I I had set the option about vertical compression display at 40, and now I see trace. The number of sample is near 3000. Now the problem is to save the file. In the last hours there were some events in my zone (3.7 Mb). I saw the traces during the event, but the files are not saved. Why? My actual configuration is: NoiseRangeToIgnore =3D 1.5 (ok for my area) =20 SampleCountToSaveFile =3D 2 =20 SamplesPerDataPoint =3D 25 =20 What I can do? I'm waiting your precious help Regards. Francesco At 17.56 15/01/98 -0800, you wrote: >Hi Francesco, > >If I understand you correctly, you are not seeing any data trace (line)=20 >on the screen, right? > >When this happens to me, it is usually a mistake in the values for=20 >ADCValueAtMinVolts, ADCValueAtMaxVolts or ADCValueAtZeroVolts. =20 > >Here is what to do. Start EMON and then press F2. This will start=20 >showing the actual sample value (a number) in the upper left corner of=20 >the screen. If this value stays near zero, then your A/D board range=20 >should be Max=3D2047, Zero=3D0 and Min=3D-2048. If the value you see stays= =20 >near 2048, then your A/D board range should be Max=3D4095, Zero=3D2048 and= =20 >Min=3D0. =20 > >Please try the F2 and tell us what numbers you see. Also, have someone=20 >jump up and down near the sensor and tell us what the highest and lowest=20 >number you see. > >Regards, Ted > >>=20 >> I checked the channel viewing: it's 0 and ok. >> The other possible channels are not installed and so the set in .opt file >> at line address 2^, 3^ ch. is 0. >> So, I'm using the 0 ch. and in pin connector i've choosed: pin n=B0 1 for >> input analog(positive) and pin 20 for ground. Is it right? >> If the connector from sensor is disabled from female board conn. the= signal >> is a blank continuos line. When i connect the sensor that line disappear. >> Why?????? >> At last: in .opt file there is an option about ADC values. But the choose >> in the 3 option where is? >> Graciously >> Francesco >>=20 >>=20 >> At 06.40 13/01/98 -0800, you wrote: >> >Francesco >> > Check which channel you are monitoring (F7 on my version) and make >> >sure you have the correct entries for the other two of the three >> >possible channels in the .OPT file.=20 >> > Barry >> > >> >Francesco wrote: >> >>=20 >> >> Thank very much Bob, Ted and Jim. >> >>=20 >> >> The I/O address it's ok and the board seems to function evenly. >> >> But I believe to have any other problem. >> >> If are not there events, must I see any trace in the screen or no? >> >> I see that the program runs, but I don't see any trace and no file is >> >> saved. Is that regular? >> >> These is the setting values: >> >> noise zones =3D 1% >> >> convert per sample =3D 25 >> >> buffers =3D 4000 >> > >> >_____________________________________________________________________ >> > >> >Public Seismic Network Mailing List (PSN-L) >> > >> >To leave this list email listserver@............. with the body of the= =20 >> >message: leave PSN-L >> > >> > >> FRANCESCO NUCERA >> OSIMO - Ancona - >> ITALY >>=20 >> Lat. 43 29" E - Long. 13 29" E >>=20 >>=20 >> _____________________________________________________________________ >>=20 >> Public Seismic Network Mailing List (PSN-L) >>=20 >> To leave this list email listserver@............. with the body of the=20 >> message: leave PSN-L >>=20 > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the=20 >message: leave PSN-L > > Francesco Nucera Osimo - Italy Lat.43.29N Long.13.29E _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Northern CA/NV Quake Date: Fri, 16 Jan 1998 15:17:00 -0700 If you go outside and wave, I could probably see you from my office window. :> I'm at the top of the Virginia Foothills development near the red roof barn house, Rancho Verde Drive. Although I was probably sitting here at the ol' Mac, I missed the quake. UNR said it was felt in Carson City; I doubt it, that's pretty darn far away for a M3.8 (USGS) or M3.5 (UNR) -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Erich F. Kern" Subject: e-mail address Date: Fri, 16 Jan 1998 15:23:13 -0800 This is primarily for Meridith Lamb; I just had 2 e-mails returned as address unknown. The address I used for Meridith is: psnseismograph52@.......... If you have a correction for this would you please send it. Thanks Erich Kern *************************************************************** Please visit our web site at: http://www.dconn.com/FatQuartersSoftware Thank you *************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: pendulum periods Date: Fri, 16 Jan 1998 20:40:09 -0600 (CST) Barry, re simple aand inverted pendulums: Inverted pendulums were very popolar in the days of optical magnification, and, yes, they have considerable instability problems. In fact, some ingenious oil-filled dash-pots were used in an attempt to couple shorter period velicity or displacement output to the mirror systems while attenuating the tilt noise. The chief drawback of an inverted pendulum is that all the parameters are locked up in the mechanics; they cannot be readily adjusted, and many things/parts are thermometers, like the spring stiffness, etc. Aside from this, a reasonable mechanical system can be used in the VBB configuration. But since the 50's, horizontals have used the "Press-Ewing" or garden-gate configuration, either with the vertical-post-wire- to-mass-with-reversed-taught-wire hinge like the Columbia- Sprengnether LP, or the vertical crossed-flexure hinge, which is suitable for smaller masses, like the commercial VBB sensors. I used it on the prototype horizontal that is shown on a photo on the web page. (the entire hinge-post-flexure assembly is epoxied together; if you want more photos, I will scan them; ps.:I am interested in feedback on what you want to see vs size, etc. I just found my old close-up lens for my SLR camera). Regarding your question of yesterday about simple pendulums: Simple means that the support has minimal mass, like a string. The period is independent of the mass for small angles. This is why kids and their parents swing at about the same period on the swing set in the park. The period is: Tn = 2*pi*sqrt(L/g), L in meters, g=9.806. So a 1-second pendulum is 0.248 meters long, or 9.78 inches, which is a very handy length for pendulum escapement wall clocks. If we want a real long period, like 20 seconds, the length is about 100 meters. 30 seconds takes 225 meters, or the atrium of a 80 story building (makes a nice Focault (spelling?) pendulum.) But impractical for a seismometer. But a real physical pendulum has distributed mass, and Tn= 2*pi*sqrt(k/(M*g*r)), where k is the moment of inertia, r is the distance from the pivot to the Cm (center of mass), and M is the mass. So now the L of a simple pendulum is equal to k/(m*r), which is called the "reduced" pendulum length. What you were observing as you increased the mass was that the moment of inertia k was increasing, lengthening the period. But the period can never be longer than that of a simple pendulum of the same length. So the determining factors are L and g. So if you can reduce the proportion of g acting on the mass, the period lengthens by the square root of the change. So if we make a "rigid" hinge, and turn the suspension sideways to become a boom, we can get 1% of g at a small angle, and our 9.78 inch pendulum now has a period of 10 seconds rather than 1. As the angle approaches true horizontal, the percentage of g goes to zero, and neglecting the hinges, the period becomes infinite. I hope this answers your questions, regards Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Computers....UUGGHHHHH! Test...msg Date: Fri, 16 Jan 1998 21:16:25 -0700 Erich Kern, Apparently you are right, my US West mail server was down and not accepting anything from anywhere. From AOL to US West, it doesn't seem to make any difference for me, problems of one nature or the other. I expected more from US West...dreaming I guess....they are all imperfect. If I were fishing for a positive note this time, it wasn't my computer at fault. In the humor aspect, just last night I mentioned that I hadn't had problems for about 2 weeks........MURPHY Bingo! Question to PSN members, anybody have a national server, that has like a perfect record? Pse let me know...thanks. Erich, ok on your similar surplus adventures in California. Them were the good old days....in a way. Actually part of the Seismic Scene article was pointing away from the past that we have known, and re-directing the reality of it all more toward the present days goodies. The prospect of the present looks alot more inviting than stuff of the past, mainly because of the availability of common components. Back to the past: Yes I have a drum recorder, but it isn't in use....no amplifiers. I speculate on using it for a strong motion general type machine sometime. Missing parts too. Currently I use an Easterline-Angus Speed Servo II strip chart recorder circa maybe the mid 70's. One of my better cheapo finds....$35.00 in a surplus store. It looked like it had little use, too clean, no ink stains. Turned out that whoever had it before had tried to load a chart roll that was too wide and stripped one of the rubber drive belts. Converted to a long length "drum" recorder, simply by removing the shredded take up belt. The ink reservoir was also damaged...removed and put in my own pen holder and use Pilot razor point pens, which are good for 4-5 days of use. Installed a bigger zero pot and connected a mechanical gizmo mechanism for the 24 hour span. 20 year old thing, and capacitors do their last gasp thing occasionally. Fast for a chart recorder in response. Nice for viewing whats going on now, but the reliability thing is a problem that doesn't go away. 3 days to convert. Chart recorder or drum, kind of the same thing, but certain chart recorders allow for a long conveyor belt like "drum". Well....here I am carrying on too far again... This msg is really a "test" msg. If I were just to say test on a msg, nothing is conveyed if its successful. Thanks for the 3 inquirys today. Regards, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Re:Photo Feedback on STM-8 AND prototype horizontal Date: Fri, 16 Jan 1998 22:09:24 -0700 S-T Morrissey wrote: (parts of previous msg deleted) > But since the 50's, horizontals have used the "Press-Ewing" or > garden-gate configuration, either with the vertical-post-wire- > to-mass-with-reversed-taught-wire hinge like the Columbia- > Sprengnether LP, or the vertical crossed-flexure hinge, which > is suitable for smaller masses, like the commercial VBB sensors. > I used it on the prototype horizontal that is shown on a photo > on the web page. (the entire hinge-post-flexure assembly is > epoxied together; if you want more photos, I will scan them; > ps.:I am interested in feedback on what you want to see vs size, > etc. I just found my old close-up lens for my SLR camera). > Sean-Thomas > > Sean, I would be interested in an additional photo on the web that reveals more details of your STM-8, which close-ups the spring retention mechanisms. Both the bottom base and the upper on the boom. I have stared at the horizontal for several days and am also very interested in the hinge mechanism from what every angles or closeups are possible. The broad view is good but its the closeups that click on understanding. The hinge-boom attachment from the above is also a subject of interest. Also any details I can't see that are of a major difference from the vertical, mechanically. Am pushing my luck....as all this takes gobs of time for you I'am sure, but...more details overall of the horizontal will be very much sought after by myself and probably a mob of the rest of us on the PSN and web. Guess I'am really offering encouragement to publish and appreciation. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: EAservoII Date: Fri, 16 Jan 1998 23:17:28 -0600 (CST) Meredith, That Esterline Angus Servo II recorder has been the workhorse of my monitor recording drums at SLU for the past 28 years, and they are still going. For one triple drum recorder (we have four) , three EA units were reassembled with the electronics installed in a rack drawer and the linear pen motors mounted to a pivot bar (to lift the pens to change the paper) above a modified 3-channel photographic drum. The drums rotate every 15 minutes or 1 hour (SP or LP data), and the helix screw inside the drum shaft translates them sideways 10" every 24 hours, (the rates are actually metric) making a standard 10" x 36" seismogram. I use inverted 4-oz ink bottles in a bubbler arrangement that provides a month or more of ink to the pens before the bottle has to be refilled. (yes, ink; I have converted all my single channel recorders to write with a fine warm hairpin stylus on fax paper; very reliable, affordable, and capable of a consistent fine line). If you need any info or parts, let me know. I have been pretty successful at rehabilitating the servo chopper, which resonates at 400 hz. The tubes last forever. Re your posting yesterday while you ate a spam sandwhich in persuit of the holy grail: have you seen the Monty Python game for DOS? One seeks out the grail (somewhat undefined) while collecting cans of SPAM, while having to identify a tree that keeps popping up (the game ends if you don't identify the LARCH tree). Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: VERTICLE.ZIP Date: Sat, 17 Jan 1998 00:26:37 EST TO: STEVE HAMMOND, ET.ALL I would appreciate if you or someone on the list could EMAIL me "VERTICLE.ZIP or VERTICLE.GIF". Thanks. Jim Allen EMAIL: RADIOTEL@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Computers....UUGGHHHHH! Test...msg Date: Fri, 16 Jan 1998 23:49:51 -0700 During 1997, my ISP was down all of maybe two or three times, all of course during the times I needed it most. Then today, their ftp server crashed. Blast! Just when all the newspapers are calling for their weekly graphic. My patience, however, has tempered throughout the years, imploying every back-up system I could think of to "meet the ol' deadline". Gosh, even did one of those modem to modem transfer today. It wasn't too long ago that it was the norm and the internet was, well, this nebulous thing and the www was something of the future. Still amazes me how far this has come in such a short time, how easy file and graphic transfers have become, web sites and instant info at a click of a button. And listening to Bill Gates talk about procesors doing 100 M calculations per sec in home computers in the next two years boggles my mind. Now if I could just afford one..... Oh, BTW: I passed the month test with the Mammoth Times and they have accepted my proposal for a year contract. Too wigglie to sit still!! Here is a copy of the graphic: http://www.seismo-watch.com/EQNEWS/Newspaper/NewspaperGraphics/MTSeismo.jpg Sorry you can't read the text in this image. T'was in a big hurry when I put it up. I'll see what I can do later. -- ---/---- Charles P. Watson Seismo-Watch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Doug Crice Subject: ISP ratings Date: Sat, 17 Jan 1998 08:28:01 -0800 Meredith, re ISP's I recently read a summary of comparisons between ISP's. The best provider varied, but IBM and ATT were near the top on all five for user satisfaction. AOL was right at the bottom on all five surveys. Doug Crice _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Seisguy Subject: Re: ISP ratings Date: Sat, 17 Jan 1998 12:39:11 EST In a message dated 98-01-17 11:33:03 EST, you write: > AOL was right at the bottom on all five surveys. > Maybe that's because they have ZERO customer service (just try and speak to a live person there, forget it ) But for the non-techies like me, it's a trade off for having something so damn easy to navagate. Mike O'Bleness Northridge, CA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Colorado Springs meteorite...Part 3 Date: Sat, 17 Jan 1998 11:46:06 -0700 This is a followup to the meteor sighting of Jan 11th 1998, near Colorado Springs, Colorado. USA This is getting juicier all the time...... ........................................................................................... Todays Denver Post article speaks of a local professor speculating on the possibility that this particular meteor MAY actually have been a sloughed off part of the comet Hale-Bobb that whizzed through our neck of the solar system. Reasons for the possibility are that the earth intersected the comets trail last Sunday, and, that the direction of the meteor (southwest to Northeast), is in opposition to most meteors who travel (generally) east to west. No meteorite fragments have been known to have been found at this time. ........................................................................................ Personally...... I would expect that the Colorado Tourist industry likes this kind of thing....even though the guests might be walking around with binoc's, metal detectors, magnetometers and weji boards and perhaps bringing strange bags back with green coke bottles clinking around inside. Somehow, I feel like all this should have been retitled into the past movies of: The gods must be crazy....not I or II but....part 3. Sensible people like myself would find the fragments to be more useful than simply mounting on a museum shelf...I'd mount it as a seismometer mass. (Its the altitude here!) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: shammon1@............. Subject: Re: VERTICLE.ZIP Date: Sat, 17 Jan 1998 11:06:20 -0800 Done-- I sent verticle.gif to your Email at AOL. Regars, Steve Hammond PSN -- San Jose RADIOTEL wrote: > > TO: STEVE HAMMOND, ET.ALL > I would appreciate if you or someone on the list could EMAIL me "VERTICLE.ZIP > or VERTICLE.GIF". > Thanks. > Jim Allen > EMAIL: RADIOTEL@....... > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Colorado Springs meteorite...Part 3 Date: Sun, 18 Jan 1998 11:16:10 +1200 >Personally...... Sensible >people like myself would find the fragments to be more >useful than simply mounting on a museum shelf...I'd mount >it as a seismometer mass. (Its the altitude here!) U have got to be joking mate i dont call that sensible with fresh meteorite material costing up to US$100.00 per gram u i could sell it and use the money to buy materials for all the seismo great u ever wanted. u obv. dont realise the value of this stuff i buy meteorites and tektites from all over the world its one of the best investment systems u will find. the price of this material is rising at ~15-20% per yr. its price ranging from a few $$ /gram to US$2000 / gram is governed by several factors.... availability of samples; age; composition = stone, stony iron, iron; where it came from eg the moon, asteroids, mars (martian material is the material up to US$2k) if material is from an observed fall this also bumps the price high (fresh fall meteorite) well meredith there it is u gave me a laugh for the morning but i couldnt resist responding. no amount of attitude could presuede me to use 5 to 10 lbs of meteorite as seismometer weight take care have a great day Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: Re: VERTICLE.ZIP Date: Sat, 17 Jan 1998 17:12:37 EST STEVE HAMMOND: Thanks Steve for Vertical.GIF. I appreciate your help. Jim Allen Cerritos, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Dewayne & Linda Hill Subject: Re: Colorado Springs meteorite...Part 3 Date: Sat, 17 Jan 1998 23:03:49 +0000 At 11:16 01/18/98 +1200, you wrote: Meredith, Call me I'm ready to go. After all Elbert count is only 250 sq. miles in size. We should be able to find it before sunset. HA HA. Dewayne. >>Personally...... >Sensible >>people like myself would find the fragments to be more >>useful than simply mounting on a museum shelf...I'd mount >>it as a seismometer mass. (Its the altitude here!) > > > U have got to be joking mate i dont call that sensible with >fresh meteorite material costing up to US$100.00 per gram u i could sell >it and use the money to buy materials for all the seismo great u ever wanted. > > u obv. dont realise the value of this stuff i buy meteorites and >tektites from all over the world its one of the best investment systems u >will find. the price of this material is rising at ~15-20% per yr. > its price ranging from a few $$ /gram to US$2000 / gram is governed by >several factors.... > availability of samples; age; composition = stone, stony iron, iron; >where it came from eg the moon, asteroids, mars (martian material is the >material up to US$2k) if material is from an observed fall this also >bumps the price high (fresh fall meteorite) > > well meredith there it is u gave me a laugh for the morning but i >couldnt resist responding. no amount of attitude could presuede me to use >5 to 10 lbs of meteorite as seismometer weight > > take care have a great day > >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 > > Dewayne (n0ssy) & Linda (n0uqf) Hill Denver, Colorado USA 39.83569n 105.06270w. Elev 5660ft. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: VBB oscillations Date: Sat, 17 Jan 1998 21:30:16 -0600 (CST) Barry, An easy way to have the VBB system oscillate is to have the connections to the feedback coil reversed; in this condition the thing will bang around in a severe fashion. Of course, I assume that you have explored this possibility. The other place to look is the Td or the time constant of the displacement transducer, which includes any buffer amplifier. It should be reasonably short wrt the mechanical period, ie less than 0.02 seconds (50hz). My experince, though,is that if it is real short, the feedback will oscillate or humm at some low audible frequency. I use a single R-C filter at the output of the displacement detector demodulator, like 2k to 4k ohms into 1 to 4 microfarads (non-polarized, of course). 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, or the value of r is too small. The response should be quite flat. I hope this gets you going. Right now the data here in "the east" is dominated by 6-second storm microseisms because of the severe weather off the east coast. The continental crust acts like a waveguide for the first harmonic of the 12-second surf pounding on the shore. Fortunately they are so monochromatic that they can be reduced on a monitor record by a factor of 100 or so by a passive "twin-T" notch filter. So although my digital data shows them peaking at 20mv, they are less than 1mv on my monitor recorder. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: E-A speed servo Date: Sat, 17 Jan 1998 23:47:23 -0700 Sean, I find your msg on the Esterline-Angus speed servo's very interesting and with the substitute fax paper, ink stylus approach to be a very practical way around the normal route. The ink and bubbler arrangement you mentioned does have my curiosity though. Ink always seems to vary chemically and from one brand to another...what do you use, get it from, price, address etc. The ink bubbler does present the other mystifier....what is it? Most of my experience is just the simple capillary action pen stuff. Even the ink pens I have used (tubes) vary in their ability to do the job. Could this be also an innovation subsititute you use? I do use simple commercial pens at the moment but this can be changed of course. Anything better is always of interest. The longevity part of your E-A recorders must be due to your careful attention. The speed servo's penmotors part I like best is their resistive plactic flat pot...easy to clean, and relatively frictionless. As far as the tube part, I'am a well known anti- tube type person; my earlier days drove me away from them. Actually my total inexperience is the real culprit I suppose. .....Nah....I'am definitely not a tuber.... E-A came out with a variety of models like all manufacturers. I'am not sure (moot point anyway), but I think the ones you have are these early ~ 5 inch or so linear penmotors. Later they came out with ~10 inch penmotors with the same basic design. Your long time use speaks volumes in regard to reliability. I can visualize your rehab of the choppers...must be delicate. My only look see was to see whats inside along time ago. Actually I have 2 solid state units, model L1101s, and I'am guessing they were made... from the label....in 1977. No manuel or schematics of course. Wrote to E-A some time back, no answer....probably all that stuff was scrapped along time ago. Also have E-A penmotors salvaged from other early digital gizmos. These look inviting for simple (I hope) amps. Endless visualizations of use over time. There was a variety of use for these penmotors besides the regular tube types ranges. Thanks for the offer of info or parts. The info asked above is the present driving curiosity. These E-A penmotors were one of my early most sought after item. Used to visit the Green Building in Golden were they had a variety of operating recording instruments. (GOL). They used several there in the same confiuration that you seem to have there.....over the same type of drums whether single or triple drums. They closed down access some years back, too bad as it was only a block or two from NEIC and their displays. Hmmm, maybe its still accessible but in another part of the building, dunno. Anyway....nothing showed up on the surplus market around Denver till maybe latter 1980's with these E-A penmotors. Getting back to my first views of these...I fell in love...or maybe it was really greed, or envy...which is greed...ok....greed...but it took along time to get one. Brother is a Monty Python fan. Me....I go for the movies of "The Gods must be crazy" part I & II. Don't usually watch anything twice, but these 2 I do. Inspirational don't you think? I suppose they are really a kind of speeded up version of real life dumb things. A person has to laugh at alot of things or else find a way to go nuts from taking things too seriously. Humor is an important part of life, and its best served upon others, if at all possible.... Regards, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Disfunctional USGS "cr" Server? Date: Sun, 18 Jan 1998 09:34:25 -0700 Have you noticed some of the USGS web sites have been slow to respond lately? They all seem to pass through the "cr" server, such as: http://wwwneic.cr.usgs.gov http://gldss7.cr.usgs.gov http://aslwww.cr.usgs.gov http://geohazards.cr.usgs.gov All the other USGS servers pop up quite quickly. You can check them from this URL: http://www.usgs.gov/network/science/earth/usgs.html Something is not working right somewhere and I am wondering if other people are experiencing similar slow connections as well. -- ---/---- Charles P. Watson Seismo-Watch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Meteorite....Part X Date: Sun, 18 Jan 1998 11:05:35 -0700 Dave Nelson, I am really inpressed with your meteorite knowledge Dave. Words like stony, iron, martian,...boy, they really expand the field as I don't know it. HHMmm....wasn't there a variety called Exasperite?..... My daily supermarket tabloid says meteorites have been known to be worshipped in various place in the world. They have also been used for their practical metal content in southeast Asia and the middle East for swords, knives etc. Even the American Indians have displayed some reverence for these objects. Uhh.. .....like tools....Dave? Well....Dave....you're absolutely right....I've decided that it wouldn't be proper for me to use a meteorite as a seismometer mass. This is due dimly to the fact, that at the present......... I don't have any stuff. However Dave,....being as you're a meteorite dealer...and you probably have access to gobs of the stuff, you are probably the best person that I know of, that may have an excess of various meteoritic materials. You probably also have the equipment that can work them into proper shape, via...... diamond tipped power chain saws and the like. Chosing the right material for the job, is one task, I think I'll leave to your descretion....whether its the common stoned variety or etc. The proper word I use previously was altitude,...not attitude... Dave. In this sense, I'am all wrong here. I have the wrong altitude for endeavors of this sort,...whereas your altitude is much better than mine. Anyway...the people of Colorado are probably already overwhelmed with miscellaneous notarity of sorts and don't need any more world wide acclaim. So...Dave...there you have it. An opportunity exists for you to be the first person in the world to use meteoritic material as a mass in a seismometer! Fall on it Dave! Uhhh....fresh meteorite fall?...is that your term Dave? P.S., ...I'am also willing to step aside, and have you make no mention of the fact, that the idea MAY have come from myself. I'll let you start the patent process on this Dave. So....OK Dave....Dave............Dave are you there Dave? :>) Meredith Lamb.....the unskilled meteorortrist _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: Disfunctional USGS "cr" Server? Date: Sun, 18 Jan 1998 12:30:46 -0600 (CST) I had no problem just now with a telnet (FINGER QUAKE) to neis. The "cr" designation means "central region", like there is a "wr" out in CA. and the coast. Regards, Sean-THomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: ink bubler Date: Sun, 18 Jan 1998 12:32:43 -0600 (CST) Meredith, If you saw EA pen drives on triple drums at the USGS in Golden they were probably the same vintage as the ones I am running. Sprengnether Instruments (down the street from the Univ) made about a dozen of them in 1965. (they still make a single component drum recorder, but they use the MFE torque motor, which can be translated easier than drum for helical recording). Three of the EA triple drums went to the new strainmeter observatory in a lead mine south of here that was my first challenge in 1969, and the rest went ??. I got one back several years ago, and also retrieved some complete ServoII units from the Aleutian station at Adak (were part of the strainmeter projuct there that was worring about the geological impact of the mega-nukes "Cannican" and "Milroe" (I think) on Amchitka Island. For pens, I have been getting just the stylus from Sprengnether and fitting it to the EA unit; the drawn down fine part of the tip wears out after several years. Kinemetrics also makes a very fine ink pen that will produce an 0.1mm line; I scored a handful of them when we bought some rehabbed single-drum recorders (like you now see at the USGS) that I converted to hot stylus and FAX paper. Re ink: we get ours from Graphic Controls (I don't have info here) in 8 or 16 oz bottles, with different colors for different stations. A secret about inks is that you should never use water to clean the pens or the feed tube: it makes the ink gell. Use hardware-store alcohol. Because if the fineness of the pen tips, absolute cleanliness is required in handling the ink; latex gloves are also a good idea. The "bubbler" is a large (1.5"sq") plastic block with a 5/8" or so (depends on the cap) round reservoir drilled about 1" into it. The cut-off or drilled through cap of a 2-oz or 4-oz poly bottle is glued upside down into the top of the hole. A smaller hole (1/8") is drilled at an angle from the top into the bottom of the reservior and accommodates the thin metal tube that connects to the long (6") capillary feed tube to the moving pen. To fill the bubbler, the bottle is filled with ink and a large syringe with a tube on it is installed in the small drill hole of the reservoir. Then you hold your breath (and protect everything with paper towels) and quickly invert the bottle of ink into the glued in cap. Ink will bubble into the reservoir, so as you screw the bottle into the cap, the excess ink has to be removed withthe syringe. I initially practiced this with water over a sink; a removeable reservoir avoids the anxiety, but runs the risk of falling off the pivot bar that holds the pen motors. I mount the bubbler directly on the side of the pen motor, where the original ink cartridge was mounted. The level of the ink in the reservoir should be about the same height as the pen tip on the paper. And a final rule about ink pens: they always get AFU after 5PM on Friday, and I hastily fix them WITHOUT latex gloves, and the ink is not exactly washable. Rule 2 is that Mother knows when the ink on a monitor recorder has run out AND when the redundant digital systems have gone OTL, and pushes the button on the quake we have been waiting for. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Bone Subject: Re: Meteorortrist? Date: Sun, 18 Jan 1998 10:59:40 -0800 meredith lamb wrote: > :>) Meredith Lamb.....the unskilled meteorortrist > Aw, c'mon Meredith! You can't be that unskilled - anybody who can come up with a title like meteorortrist deserves some kind of an award, especially when it follow a post like yours! I propose you receive the 'socioseismohumorist par excellence' recognition for today, since it's so quiet otherwise. -- Jim Bone _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Canie Brooks Subject: Re: Disfunctional USGS "cr" Server? Date: Sun, 18 Jan 1998 11:06:33 -0800 At 12:30 PM 1/18/98 -0600, you wrote: >I had no problem just now with a telnet (FINGER QUAKE) to neis. >The "cr" designation means "central region", like there is a "wr" >out in CA. and the coast. >Regards, >Sean-THomas I got thru to the world quake list - Noticed a 3.0 for Northern Cal which wasn't on the http://www.scecdc.scec.org/recenteqs/Maps/123-39.html list... The Geysers area.. should have happened about 6:49am PST but the list stops at 5:05 am or so.. (Its now 11:06am PST) > >_____________________________________________________________________ > >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: kathy mortensen Subject: Re: Disfunctional USGS "cr" Server? Date: Sun, 18 Jan 1998 11:56:51 -0700 Canie Brooks wrote: > > At 12:30 PM 1/18/98 -0600, you wrote: > >I had no problem just now with a telnet (FINGER QUAKE) to neis. > >The "cr" designation means "central region", like there is a "wr" > >out in CA. and the coast. > >Regards, > >Sean-THomas > > I got thru to the world quake list - Noticed a 3.0 for Northern Cal which > wasn't on the http://www.scecdc.scec.org/recenteqs/Maps/123-39.html list... > The Geysers area.. should have happened about 6:49am PST but the list stops > at 5:05 am or so.. (Its now 11:06am PST) > > > > >_____________________________________________________________________ > > > >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 For calif. I use http://quake.usgs.gov/recenteqs/ the 3.0 at the geysers this A.M. was there at 9 A.M PST when I checked!! SKM P.S. hours of uncontrolable laughter from the "Meredith - Dave" soap opera ---- had to print it!!!! ha ha hahaha hahahahah funny stuff!!! _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: Web page update Date: Sun, 18 Jan 1998 18:26:40 -0800 Hi Arie, Great job of constructing your sensors and documenting it. Looking forward to seeing some seismograms soon. Regards, Larry Cochrane Redwood City, PSN At 03:41 PM 1/18/98 +0800, you wrote: >Hi Larry, > >Good news, I've just finished the mechanical constructing phase of the two SG >seismometers and thought you may be interested to see the updated page. > >web page: http://iinet.net.au/~ajbv > >The only thing that's needed to be done is to box and connect your electronics to the >A/D card and repair the GPS micro-controller. I wired the micro-controller to >wrong polarity!! > >Regards > >Arie Verveer >ajbv@............ > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Meteorites, to those that responded Date: Mon, 19 Jan 1998 15:34:50 +1200 hi , Meredith, Clark, Dick, and all others interested, Firstly I am not a dealer just a very avid collector of meteorites. they are another branch of my ever expanding collection of rocks, minerals and fossils. With my love of both geology and astronomy the coming together of these was inevidable (SP?) with the collecting of rocks from space. I work closely with one of my university lecturers in the geol. dept. He has a lot of experience with meteorites and also runs the xray fluorescence spectrometer and along with thin section microscope slides we can determine the origin of samples brought to us. its a bit difficult to give a sample amalysis without seeing it in the " flesh" as many meteorites have very similar looks to terresterial rocks. but as some hints and guideslines..... 1) There are 3 main groups (which have many subsections) Irons, Stony Irons and Stones. The Stones have 2 main classifications Chrondrites and Achrondrites. Note: virtually all meteorites will be attracted to a magnet, even the stony ones have up to 15% iron content. stony-irons are up to 90% iron/nickel and of course irons are 100% iron/nickel in composition. Also beware that terresterial volcanics especially basalts can have a high iron contents the ones around my home area are up to 20% , so will happily cling to a magnet. 2) Irons... fresh fallen ones will have a black thin (~1mm) fusion crust, the surface will be generally smooth (no sharp edges unless broken by the ground impact) but uneven, lumpy. in arid regions eg. the australian desert outback or say the Arizona region the meteorite will keep its fresh fall appearence for 1000's of years, but in humid climates the meteorite will oxidise quickly, turning rusty brown with corrosion and can resemble iron concretions found in many sedimentary rocks. If u think u have found and iron meteorite there one undisputable test and that is to slice the sample in a water cooled diamond rock saw, etch the cut surface with acid and polish it. This shows the crystalline structure called the Widmanstatten Pattern which is ONLY ever found in iron meteorites. Be wary the fusion crust on all meteorites that have oxidised a bit can be easily confused with a normal weathering rind found on most exposed terresterial rocks. 3) Chrondrites.... are fine grained stoney meteorites that very closely resemble earthly basalts. The description comes from the small (~1-2 mm diam.) spheres (chrondrules) found through out the rock. A recent sample brought to me for identification fitted the description perfectly and even my lecturer look at it and said " very possible". but the spectrom. analysis showed a good potassium spike which is not found in meteorites. Instead the sample had all the attributes of out local basalts in composition. Oh well... good try :)) 4) Achrondrites ... as the name suggests doesnt have the chrondrules present. They are also much coarser, ranging from the look of a granite in crystal size and structure to large coarse lumps... brecciated rock. The stoney meteorites have a composition of ~30% pyroxene, ~40% olivine, ~10% plagioclase and ~5 - 20% nickel-iron. Finally there is one other conclosive test for all meteorites or would be ones and it can be done in only a handful of labs around the world. When the meteor is in space it is constantly being bombarded with cosmic rays this produces substantial 26Al isotope. If these fragments have had cosmic exposures of at least a few million yrs, then their surfaceswill reach saturation in 26Al production (t1/2 = 0.7 Myr). After falling to earth, the atmosphere shields the meteorite from further 26Al production. and the decay of this isotope can be used to determine how long it has been on earth. a WWW site of interest... these ppl also will do possible meteorite tests on samples sent to them they require only a thumbnail size piece. http://eps.unm.edu/iom/ well guys not exactly seismology but damn interesting anyway cheers Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: step calibration Date: Sun, 18 Jan 1998 22:34:39 -0600 (CST) Barry, The step response, either due to a current in the calibration coil or the lifting of a small test mass, contains all frequencies of interest. It is also a change in force: aka acceleration. So to compare it with the velocity response predicted by the transfer function, isolate the data segment and take the FFT of it (I use MCADs complex FFT), and then divide the FFT values through by omega**2 (once is because of the step, the second is because the output voltage is velocity and the input is acceleration). The resulting response should look like the transfer function within the limits of your digitizer. An example of this is in figure 10 (I think; I rearranged them) of my web page of figures and schematics. The agreement is good from 10 seconds to 500 seconds. Local and microseismic noise dominates the spectrum at less than 10 seconds. I could use a larger step pulse, but my digitizer is limited to 12-bits. My digitizer is also one sample/second, so the nyquist (minimum useful frequency) is 2 seconds. I have to rely on my monitor recorder for short period data, like local events. (Teleseisms are generally more interesting to me.) (I am thinking of a way of putting the MCAD source for these figures out in a directory that you can download from and then open with your MCAD; the data file (xxx.prn) would also have to download). The calibration coil can also be used with a function generator to input sine waves of constant P-P current. The output amplitudes are then measured (either digitally or on a monitor recorder) and divided by their respective omega, and the resulting plot is the velocity response. If you calibrate the calibration coil (weight to balance a given current), you can calculate the absolute magnification of the instrument. I need to do this on the prototype here and then post it to show the details. A shake table is a rare luxury; the AFOSR paid for the one in our department back in the 60s. It is driven by a 5hp hydraulic system (to handle the Big Benioff seismometers that weigh 400 lbs), and operates from DC to 40 hz, 0.1 to 100 microns, with separate vertical and horizontal tables. We generally let anyone use it. So we need some more earthquakes to test our instruments. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Walt Williams" Subject: Re: zero length spring Date: Sun, 18 Jan 1998 12:20:18 +0000 Hello Charles, Thank you. Walt Williams, 98.01.18 dfheli@.............. ================================ ------- Forwarded Message Follows ------- Date: Thu, 15 Jan 1998 13:47:22 -0800 From: "Charles R. Patton" Reply-to: PSN-L Mailing List Organization: Western Digital To: PSN-L Mailing List Subject: Re: zero length spring Check out the URL: http://www.lacosteromberg.com/detail.html#physics The site is LaCoste-Romberg Co. and the particular URL is pointing at a section of their manual which describes the theory and construction of the zero-length spring and LaCost suspension in a gravity meter. Back up a bit, and you can get a full education on gravity meters they manufacture. I'm amazed. This is the first site I have come across that puts their equipment manuals on line. Charles R. Patton patton@......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Walt Williams" Subject: zero length spring Date: Sun, 18 Jan 1998 22:10:24 +0000 Sean-Thomas, Thank you. Walt, 97.01.18 =========================================== ------- Forwarded Message Follows ------- Date: Wed, 14 Jan 1998 23:31:15 -0600 (CST) From: S-T Morrissey To: psn-l@............. Subject: zero length spring Reply-to: PSN-L Mailing List Walt, Regarding "zero length" beahvior of a spring. For an ordinary spring, as it it stretched, the change in length is proportional to the force applied. If you attach a linear dial an put it in a box and step on it, it will tell you how well you prospered fron the holiday feasting. ie Hooks law: F = k *(l - lo), where k is the spring constant (force/unit length), l is the length with the force F applied, and lo is the initial length. When such a spring is used in a vertical seismometer, this means that the restoring force changes as the boom moves, making the sensor non-linear. This was solved in the 30s by the LaCoste suspension that devised a spring such that at a specific length the change in force with change in length became zero. That is, if lo = 0, so F = k*l, then F is constant. So any minute acceleration will move the mass in a linear fashion. So when such a spring is made, namely by twisting the wire (or quartz fiber in gravimeters) as the coil is wound, the spring ends up forcibly closed: it takes an initial force to open it. I won't go into the math to determine the constants, but at some opened length, lo becomes 0. With the leaf spring I use, this occurs at about a 5" opening, and is evident when the spring is installed and the opening adjusted. At one point, the boom will not stay balanced, but floats either up or down with instability (aka an infinite period). So I increase the opening slightly, and the period becomes stable. A stable period is essential for a well defined transfer function. Regards, Sean-Thomas !p _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Mb magnitude calculation Date: Sun, 18 Jan 1998 22:20:39 -0800 Hi, I'm working on adding Mb magnitude calculation to WinQuake. Does anyone know off hand if Mb is calculated using a vertical and/or horizontal sensor? Thanks.... -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Bob Fryer Subject: Re: Computers....UUGHH! & precursors Date: Mon, 19 Jan 1998 00:52:18 -0800 Hey Charles, Great! But have you checked your chair? Some of the EQ sensitives in Mojave desert, etc. are reporting ant infestations. Apparently the ants are fleeing telluric currents. Can anyone help me with any of the items listed below? Take care, Bob Fryer >Oh, BTW: I passed the month test with the Mammoth Times and they have >accepted my proposal for a year contract. Too wigglie to sit still!! >Here is a copy of the graphic: >http://www.seismo-watch.com/EQNEWS/Newspaper/NewspaperGraphics/MTSeismo.jpg > >Sorry you can't read the text in this image. T'was in a big hurry when I >put it up. I'll see what I can do later. > >---/---- >Charles P. Watson >Seismo-Watch ------------------------ Hi gang, Just received (out of the blue) the item below from Japan; apparently from a member of the team doing the work. For the present, I have removed the name and addresses of the sender. Some of the materials seem to be available only in Japanese, while others appear to be in German, Swiss or ??? -- "Naturwissenschaften." Some of the undecypherable material may have been in Kanji (Japanese). If anyone has access to English versions, please share! Thanks, Bob F ------------------------------------ Sun Jan 18 17:40:05 1998 Date: Mon, 19 Jan 1998 10:39:25 +0900 To: bfryer@............ From: ********* <*****@...................> Subject: Earthquake legends Followings are a list of publication in this field. We are involved in thes research after the Kobe earthquake. Reprints are available on request. [Signed.] 1996 96-1 Ikeya, M. and Takaki S. (1996): Electromagnetic model of a fault for earthquake lightnings (EQLs). Jpn. J. Appl. Phys. 35, L355-L357. 96-2 Ikeya, M. Takaki, S. and Takashimizu, D. (1996a) Electric shocks for seismic animal anomalous behaviors (SAABs). J. Phys. Soc. Japan 65, 710-712. 96-3 Ikeya, M. and Takaki, S. (1986): Seismic electric signals (SES) and animal anomalies. J. speleol. Soc. Japan 20, 38-47. 96-4 Ikeya, M., Huruta, H., Anzai, H. and Kajiwara, N. (1996b): Electric field effects on rats and sparrows for seismic animal anomalies (SAAs). Jpn J. Appl. Phys. 65, 4587-4594. 96-5 $BCSC+85;G(J(1996):$BCO?L$KH<$&EE<'8=>]$HF0J*$N0[>o9TF0!"2J3X!J4dGH=qE9!K(J6 6 $B4,!!(J408-418. Ikeya, M. (1996): Electromagnetic phenomena and anomalous animal behaviors accompanying earthquakes. Kagaku 66, 408-418 (in Japanese). 1997 97-1 Ikeya, M., Takaki, S., Matsumoto, H., Tani, A. and Komatsu, T. (1997): Pulsed charge model of a fault behavior producing seismic electric signals. J. Circuit, Systems and Computers 7, 153-164. 97-2 Ikeya, M., Kinoshita, Y., Matsumoto, H., Takaki, S. and Yamanaka, C. (1997): A model experiment of electromagnetic wave propagation over long distances using waveguide terminology. Jpn J. Appl. Phys. 37, L - L . 97-3 Ikeya, M. and Matsumoto, H.(1997): Reproduced earthquake precursor legends using a Van de Graaff electrostatic generator: Candle flame and dropped nails. Naturwissenschaften 84$B!"(J539-541 (1997)$B!!(J. 97-4 Ikeya, M. and Q. Huang (1997): Earthquake frequency and moment mragnitude relations for mainshock, aftershocks and foreshocks: Theoretical b-values. Episodes 20, 97-5 Sasaoka, H., Yamanaka, C. and Ikeya, M. (1997): Measurements of electric potential variation by piezoelectricity of granite. Geophys. Res. Letters 97-6 Huang, Q. and Ikeya, M. (1997): Electric field effects on animals: Mechanism of seismic anomalous animal behavior (SAAB). Earthquake Research in China. 97-7 Huang, Q. and Ikeya, M. (1997): An experimental approach to the electromagnetic phenomena associated with earthquakes. Ionics . 97-8 Ikeya, M., Komatsu, T., Y. Kinoshita, Takaki, S., Teramoto, K., Inoue, K., Gondou, M. and Yamamoto, T. (1997): Seismically-induced anomalous animal behavior (SAAB): Electric field before earthquakes at Kobe-Oji Zoo and Izu-Atagawa Tropical Banana-Alligator Garden. Episodes. $B!!(J 97-9 $B!!CSC+85;G!J(J1997$B!K!'0B@/8+J9O?$r@5$9!J(J1$B!K!"%(%3#J!!CO?L$HKI:R#14, (JNo.6,$B!!(J 70-74. 1998 98-1 $BCSC+85;G!J(J1998$B!K!'CO?L$NA0!"F0J*$O$J$ > Hey Charles, > > Great! But have you checked your chair? Some of the EQ sensitives in > Mojave desert, etc. are reporting ant infestations. Apparently the ants > are fleeing telluric currents. > My chair looks fine. I am not convinced ant behavior can indicate precursors to large earthquke activity. -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "frank murray" Subject: RE: Computers....UUGHH! & precursors Date: Mon, 19 Jan 1998 08:25:46 -0800 bob fryer asks: > > Can anyone help me with any of the items listed below? and though you probably did not mean as far below as where this is posted: > ----- earthquake WARNING research ----- > --- animals, people, scientific evidence --- > --- http://www.teleport.com/~bfryer --- i think some help there might be needed...on your site you have a long interview with a lady named charlotte who claims to predict earthquakes, volcanic eruptions, etc with 98% accuracy...from the interview: >Q. Are you ever wrong? >A. I'm running 98% (accurate). I wish I was wrong a lot of times. >That bothers me. incredible if true...but the interview also states (charlotte speaking): >Now the quake of February the 13th (1981), in Elk Lake, Washington -- I >think it was measured as 7.1 -- hit at 10:10 that evening. (snip) >I headed to the doctor's office and was checked over and found out I was >okay. Then I notified Colorado, U.S.G.S., and I said, "There is going to >be a major quake, probably Washington, within 72 hours, of a 7 or higher." (snip) >Just six hours later a 7.1 quake hit Elk Lake, Washington, near the volcano. here's the cnss catalog data for that quake (time in UTC): >date time lat long depth mag >1981/02/14 06:09:27.21 46.3493 -122.2360 7.28 5.20 cnss says it was a M5.2 quake, not a M7.1...in short, the listed magnitude of the quake is between one and two percent (1% - 2%) of the magnitude that she claims...where's the other 98% of the magnitude from??...perhaps the same place as her: >...I'm running 98% (accurate). perhaps you might post a warning on your website for any who might otherwise take seriously her claims... cheers, frank for my electronic college proposal: http://home.att.net/~fjtmurray/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: [Fwd: Volcano Tours in 1998] Date: Mon, 19 Jan 1998 15:30:14 -0700 FYI -- ---/---- Charles P. Watson, Seismo-Watch PLEASE DO NOT USE REPLY TO RESPOND TO THIS MESSAGE ----------------------------Original message---------------------------- ________________________________________________________________________________ VOLCANO TOURS in 1998 Volcano Tours, a Rhode Island-based company, offers a variety of excursions to the volcanic regions of the Earth in 1998, led by local volcanologists or scientists with experience in the region. Tours in 1998 include: Costa Rica: Departures on March 5 to 15 1997, and November 5 to 15 1997. Leaders are Guillermo Alvarado and Haraldur Sigurdsson. This tour includes Poas, Miravalles, Arenal, Cerro Chopo, Cerro Chato, Turrialba and Irazu volcanoes. Italy: Departures 1 to 15 May 1998, and 9 to 21 October 1998. Leaders are Haraldur Sigurdsson (spring) and Mauro Coltelli (fall). Tour includes Pompeii, Mount Vesuvius, Herculaneum, Campi Flegrei, Monte Nuovo, Stromboli, Lipari, Vulcano and Mount Etna volcanoes. Indonesia : Departures are June and August 1998, Leaders are Haraldur Sigurdsson and the Indonesian geologist Sutikno Bronto (June) and Steven Carey and Sutikno Bronto (August). Tour includes a cruise of the Krakatau volcanic islands in the Sunda Straits, Anak, Sertung and Rakata, Merapi volcano, Yogyakarta, Dieng Plateau, Borobodur, the island of Bali, including Batur, Agung and Ubud. Iceland: Departures are 4 to 18 July 1998, 8 to 22 August 1998. Tour leaders are the Icelandic geologists Gudrun Larsen and Haukur Johannesson. Tour includes: Blue Lagoon, Reykjanes peninsula, Vestmannaeyjar, Heimaey,Thingvellir, Laugarvatn, Geysir, Gullfoss, Hekla volcano, Laki fissure, Eldgja fissure, Landmannalaugar, Sprengisandur desert, Myvatn, Krafla, Tjornes, Asbyrgi, Dettifoss, Akureyri, Kjolur, Hvitarvellir. For details and a brochure, contact Toni Rottenberg at Volcano Tours at 7 Wildflower Road, Barrington RI 02806; tel. 800-923-7422, 401-247-0038; fax 401-247-0270; or check their web site at http://www.volcanotours.com ---------------------------------------------------------------- Haraldur Sigurdsson, Professor Graduate School of Oceanography University of Rhode Island, Narragansett, RI 02882-1197 USA Tel. 401-874-6596; home: 401-423-0247; Fax: 401-874-6811 e-mail address: Haraldur@................... __________________________________________ From: Larry Cochrane Subject: New WinQuake beta release Date: Mon, 19 Jan 1998 15:55:33 -0800 Greetings, I released a new beta version of my WinQuake program. Both 16 and 32 bit version are available. The 32 bit version, for Win95 and NT, are at the following URLs: ftp://ftp.seismicnet.com/users/psn/software/wq32b4.zip or ftp://psn.quake.net/software/wq32b4.zip and the 16 bit version can be download at: ftp://ftp.seismicnet.com/users/psn/software/wq16b4.zip or ftp://psn.quake.net/software/wq16b4.zip Please and use the ftp.seismicnet.com address if possible. Heres what's new. Map Feature; This new feature uses the default Web browser loaded on the system to display either the station and/or the event location using the Xerox map system at http://pubweb.parc.xerox.com/map. Under the View menu item you will see three new menu items. One displays both the event and station location and the others display either the station or event. This feature is used one other place. In the Report dialog box you will see a new button called "View On Map". This button will view the currently selected item in the report list. If the View menu items, or the Report button, are disabled then WQ was unable to find a default browser on the system. This is really a neat feature and I use it often, wish I could say I thought of it... Mark Halliday, our Ben Loma, California PSN station suggested it. Thanks Mark! FFT; When Edward Cranswick was out here for the AGU meeting in December he helped me add some new features to the FFT section of WQ. You can now change the sloop of the filtering by specifying the number of poles of filtering to use. You can also save a default freq. and number of poles to use for each of the filter types. WQ can now display the amplitude of the freq. spectrum in Log format. You can change between Log and linear by turning on/off the Option menu item "Log-Y". Thanks for the help Edward! PEPP Data set; WQ can read PEPP (Princeton Earth Physics Project) data sets. A data set contains one or more event files in one file. If you select a data set using the File Open dialog box, the list of event/dataset files will change to a list of event files in the data set. You can then select one or more files to open from there. When you select a PEPP data set the Update button title will change to "All Files". Selecting this button will re display the event files and data sets in the current selected directory. PEPP to SAC Binary Save; I added the ability to save PEPP files as SAC binary files. I also fixed a bug when you tried to save a PEPP file as a PSN file. P and S Location; When you first display an event file, and the P and S markers locations have not been saved in the header information and the event location and time of origin info is known, WQ will try and locate the P and S markers using the current default JB tables. HTML Documentation; One of the things I need to do is come up with some better documentation for WQ and SDR. What I want to do is create a set of HTML pages for both software programs. Now that WQ can use the systems web browser I have changed how the Help menu item works. Before it would open a text file and display it using Notepad. Now it send a URL, a local file in the root WQ directory, that the browser can display. Currently I converted the current doc file I have to a simple web page. In each of the WQ zip files you will see either winquake.html (32 bit release) or winquake.htm (16 bit). After unzipping the file you should copy the html file over to the directory that you use for WQ. Upgrading; If you haven't loaded WinQuake on your system, you first need to install the 2.4 release available at http://psn.quake.net/software. The beta release only has a new EXE file, and some other data/html files, so by using the install/setup program in the 2.4 release your system will have all of the other files need to run WQ properly. The first thing to do is make sure your not running WinQuake. If its running you will need to exit the program. You can't copy the new EXE file over to the working directory if WQ is running. After unzipping the beta release files into a temporary directory, copy all of the files over to the WQ directory. The default directory for WQ is c:\winqk32\, for the 32 bit version, and, c:\winquake\ for the 16 bit version. Thats it. Please let me know if you run into any problems with the new features (or old ones...). -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: New Winquake map featue Date: Mon, 19 Jan 1998 20:47:21 -0700 Larry & Mark; Your new station & quake epicenter feature works great! Very impressive indeed! Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: seismometer pier Date: Tue, 20 Jan 1998 00:24:57 -0600 (CST) Dewayne, The pad for a seismometer should be as large in area as practical, especially for a horizontal with its' tilt sensitivity. It needs to be massive but not necessarily sturdy, since the seis is rather lightweight. So if I was to make one in a crawlspace, I would just level a spot and form it up with 2x4s for at least 24x36" and then mix enough sacrete to fill the form and level it. For the "pier" in my basement here, I then stacked up and grouted together two layers (16" height) of some standard 8x8x16" concrete blocks to raise the instrument surface so working on the sensor isn't such a backache. I topped the blocks with 24" sq patio pavers, then grouted 12" ceramic tiles on top to provide a very smooth surface to mount the sensor. I don't know how much headroom you have in your crawlspace. Regarding insulation, mass and thickness is important: I have tried alternating layers of drywall and styrofoam, sealed together with duct tape, in a 4" thick sandwhich. The top and front side need to be easily removeable, so they fit with a dovetail arrangement that prevents drafts. For some amount of temperature control, you need something with a thermostat that is sensitive, or thermal cycling will be a problem. A readily available item is a water heater for an aquarium; it has to operate submerged in H2O, but a gallon jar will do. They have very sensitive thermostats. The lowest wattage will probably do. I use a radio shack indoor-outdoor digital thermometer to keep tabs on the temperature. Additional jugs of water inside the seismometer case help recovery after the cover is opened to adjust the instrument. Regards, Sean-THomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: Mb magnitude calculation Date: Tue, 20 Jan 1998 00:47:35 -0600 (CST) Larry, The Mb magnitude is usually calculated from the vertical component body waves. The reason for this is that generally the propagation of the vertical energy is not as dependent on the relationship of the earthquake source mechanism to the receiver (aka seismometer) as is the horizontal energy. The horizontal component of the shear wave propagates at right angles to the direction from the source. This is the reason why the network we had in the Aleutians consisted of only a vertical and an EW sensor at all the stations: all the quakes were in the trench south of the islands, so a NS sensor would provide little data. This is also the reason that most networks of stations are mostly vertical component sensors, although all three components are preferred if funding allows. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: bob@................. (Bob Hammond (USGS-AVO Geophysicist)) Subject: Re: Mb magnitude calculation Date: Tue, 20 Jan 1998 10:19:17 -0900 Larry, Mb is calculated from a vertical sensor. Bob _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: lahr@.................. Subject: period versus dimension Date: Tue, 20 Jan 1998 14:06:52 -0700 (MST) Hi Sean, You sure have bumped up the level of knowledge on the PSN! Thanks for all of your efforts. I'm not following many of the details, but am saving the Email for the day, who knows when, that I will try to build a seismometer. I had one question about a recent post: You write: "But a real physical pendulum has distributed mass, and Tn= 2*pi*sqrt(k/(M*g*r)), where k is the moment of inertia, r is the distance from the pivot to the Cm (center of mass), and M is the mass. So now the L of a simple pendulum is equal to k/(m*r), which is called the "reduced" pendulum length. What you were observing as you increased the mass was that the moment of inertia k was increasing, lengthening the period. But the period can never be longer than that of a simple pendulum of the same length." I'm not so sure about the last sentence above. From your equation, as r approaches zero the period approaches infinity. This would be equivalent to suspending a slightly off-balance tire by its axle, with the axis of the axle horizontal. The period would not be limited by the diameter of the tire. 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://www.aeic.alaska.edu/lahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Walt Williams" Subject: Re: A Lunchpail Amateur Seismologists Best Story Date: Tue, 20 Jan 1998 15:08:10 +0000 Hello All, A couple of years ago, I 'felt' an earthquake. It was about 04:30 am. In my sleep, I heard a loud bang noise, a sound like rumbling, maybe 15 Hz. Then all hell broke loose. In the bedroom, in the dark I went to the dresser where I always put my glasses and reached for them. But, every time I did so, the dresser was not in the right spot, so I would miss. Finally, by reaching around the dresser (small), I was able to stabilize the dresser enough to grasp my glasses. I put on my shoes and ran into the den, the lights in there were on. We have a beam which is two feet high by one foot thick and is the length of the ceiling. This was moving up and down six to ten inches, 15 to 20 times a minute, the floor was moving in waves. The TV set flipped off it's pedestal, the book rack was emptying, it was really surreal! I exited the house through the glass sliding door in the den. About now the power went out. The earth stopped moving. It had moved for about fifteen seconds. It was very strange outside, absolute animal silence. No dogs barking, no cars moving, and yet at the same time the stark stillness was intermingled with car alarms annunciating everywhere. And in the distance one could hear and see blue and purple flashes of light and the sharp reports of power-line transformers shorting and popping! As far as I could see, in any direction the city was dark, and sky was pulsating with purple flashes. Standing in the yard, I looked around and discovered my lady was not with me, gads, who would suspect she would stay in there? I assumed she was right behind me?! I must tell you, it took all my courage to go back into the house. I stood there in the side yard maybe ten or fifteen seconds, and went back into the house, then I heard the second and much louder bang, then a sound like a roaring diesel train engine and the quake started again. This time I went through the kitchen, in the dark, it was real crunchy in there, I was wondering, "what the hell is this?", later I discovered it was all of our stemware. In the hallway, half walking and crawling, as the floor and walls were moving, I made it back to the bedroom. Dolly, my girl, was sitting there, telling me it was safer in the house, I pulled her off of the bed just as the wall-unit-book-rack collapsed on to the bed where she had been. The ceiling fan also came down, the windows were cracking. The earth was moving violently up and down, with side to side oscillations at this time; very destructive motion. We exited the house through front door. It took several attempts to open it; the frame was deforming and vising it shut, I had to synchronize with the rhythm. Outside, it was fantastic, it is amazing to see just how plastic the earth is. The street, our driveway and yard was moving in disjunctured waves. This quake persisted about fourty five seconds, the first was about fifteen seconds duration with a fifteen to twenty second pause in between. It was during the second the freeways and apartment buildings collapsed in and around Northridge. This was not my first quake, I also experienced the Sylmar California Quake, but it was much less destructive. After some moments we realized everyone on our block was standing in their front yards and most were naked. When it really gets rough, all one needs is glasses and shoes! My girl is always prepared, else we would have starved, if not for her earthquake preparedness preparations. We had - food, water, camping / cooking utilities, gas lamps, butane tanks and batteries. This event was called the Northridge Quake, (LA suburb, California, USA). Every house within seventy five miles suffered at least $20,000 US Dollars damage. Many were red tagged as they were unsafe to enter. The majority of the Hispanic population would not enter their residences and were living in the city parks in US Government supplied tents. In our neighborhood, Canoga Park, telephone service was restored in about five days, electricity was restored in 14 days, gas - thirty days, and water - 20 days. My friend, who lives in Northridge, near where the freeways collapsed, did not have any services for several months. Periodically I see postings relating people's earthquake experiences, I hope you do not mind my sharing of this experience with you. The experience was awesome, fearsome and incredibly interesting. The power of the forces of physics in action can be truly mind boggling. Best Regards, Walt Williams, 98.01.19 dfheli@.............. Canoga Park, (LA suburb), California USA ========================================================= ------- Forwarded Message Follows ------- Date: Wed, 14 Jan 1998 15:14:56 -0800 To: PSN-L Mailing List From: Karl Cunningham Subject: Re: A Lunchpail Amateur Seismologists Best Story Reply-to: PSN-L Mailing List Meredith -- Very interesting story. I've been very curious if anyone has been able to "feel" a teleseismic event, and you did! Another curiosity this brings to mind is to make a "perpetual motion" machine -- a high-Q mechanism resonant at 6-seconds to pick up the background noise. The idea is to have this thing sitting there constantly moving. Perhaps a rocker with a strategically placed mass could be made into such a thing. I guess my best story is about going to Landers a few days after the big event and seeing boulders the size of a two-car garage that had tumbled down a hill, and seeing the almost 8-meter horizontal and 2.6-meter vertical offsets along the fault. There were ruptures everywhere on little fault strands going this way and that. I was standing about 5 meters away from the fault near the area of greatest offset when a M5+ aftershock occurred. I didn't feel anything, but heard a VERY low frequency rumble -- perhaps 15Hz and very loud. It sounded as though the nearby mountains were talking. I detected no movement of the fault and saw no dust, though. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: ralvarez@........ (Raul Alvarez) Subject: seismo triangulation Date: Tue, 20 Jan 1998 17:15:48 -0700 (MST) Hi Group, Just been thinking on the way home tonight (it's a long way up this mountain, have lots of time to think!:-) ), about the possibility of using 3 seismos situated about 200+ meters apart in a triangle to determine signal direction. Anyone have comments on feasability? Is there enough delay over 200+ meters to detect time/phase shift? I'm fairly new at this, so am I pipedreaming? Raul ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~ ~ ~ "My dreams are the seeds of my reality, ~ ~ nurtured in the womb of my soul" ~ ~ RJA, 1985 ~ ~ ~ ~ ~ ~ Raul J. Alvarez ~ ~ Bellvue, Colorado ~ ~ e-mail ralvarez@........ ~ ~ homepage www.frii.com/~ralvarez ~ ~ "The Renaissance Experimenter" ~ ~ experimenter in: ~ ~ Radio and Optical Astronomy, Seismology, Weather, ~ ~ Computers, Instrumentation and Neat Stuff! ~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "frank murray" Subject: RE: A Lunchpail Amateur Seismologists Best Story Date: Tue, 20 Jan 1998 16:50:26 -0800 > -----Original Message----- > From: Walt Williams [mailto:dfheli@............... > Sent: Tuesday, January 20, 1998 7:08 AM > To: PSN-L Mailing List > Subject: Re: A Lunchpail Amateur Seismologists Best Story > This event was called the Northridge Quake, (LA suburb, California, > USA). > Every house within seventy five miles suffered at least $20,000 US > Dollars damage. absolute nonsense...draw a circle of 75 mile radius around the epicenter and you find that it encloses santa barbara, bakersfield, san bernadino, and all of los angeles down to around laguna beach... excuse me...perhaps i'm jumping to conclusions...perhaps it's just that the media misreported that M10.4 quake at northridge... jeers, frank _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: period versus dimension Date: Tue, 20 Jan 1998 19:27:14 -0600 (CST) John, The r of a physical pendulum is the radius from the point of rotation to the center of mass, and the moment of inertia is k = M*(r**2), and the period T = 2*pi*sqrt(k/M*g*r). If all the mass is at the end L of the pendulum, r = L, which is a simple pendulum, and the period T = 2*pi*sqrt(L/g). As the center of mass moves towards the pivot, r decreases, and the equivalent pendulum length l = k/Mr decreases. In the simple condition that all of M is always at r, l = k/Mr =(M*r**2)/Mr = r. So as r becomes shorter, T also decreases toward zero. The original question posed was whether adding mass at the end of the pendulum will increase the period. It does to the extent that k increases, up to the point that virtually all the mass is at the free end and r = L, and the maximum period of a simple pendulum is obtained. If you have time to follow up on the homemade seismometer, I would appreciate your comments about my web pages on it at: http://www.eas.slu.edu/People/STMorrissey/index.html I have also submitted an abstract for the SSA meeting regarding the calibration of the instrument. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: period versus dimension Date: Tue, 20 Jan 1998 19:27:14 -0600 (CST) John, The r of a physical pendulum is the radius from the point of rotation to the center of mass, and the moment of inertia is k = M*(r**2), and the period T = 2*pi*sqrt(k/M*g*r). If all the mass is at the end L of the pendulum, r = L, which is a simple pendulum, and the period T = 2*pi*sqrt(L/g). As the center of mass moves towards the pivot, r decreases, and the equivalent pendulum length l = k/Mr decreases. In the simple condition that all of M is always at r, l = k/Mr =(M*r**2)/Mr = r. So as r becomes shorter, T also decreases toward zero. The original question posed was whether adding mass at the end of the pendulum will increase the period. It does to the extent that k increases, up to the point that virtually all the mass is at the free end and r = L, and the maximum period of a simple pendulum is obtained. If you have time to follow up on the homemade seismometer, I would appreciate your comments about my web pages on it at: http://www.eas.slu.edu/People/STMorrissey/index.html I have also submitted an abstract for the SSA meeting regarding the calibration of the instrument. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Caruso Subject: Re: A Lunchpail Amateur Seismologists Best Story Date: Tue, 20 Jan 1998 20:34:43 -0500 (EST) That is what this list is all about, truly a lucid experience! Well written Walt. STEPHEN CARUSO CET KB8UGH "Coincidence is a shortsighted mental delusion" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: seismo triangulation Date: Tue, 20 Jan 1998 19:46:17 -0600 (CST) Raul, Seismic wave velocities are of the order of 2 to 6 km /second, depending on the wave type. So even a slow surface wave at 2000 m/sec would zip across your 200 m array in 0.1 second. Small arrays have been used for azimuthal data, but they are usually at least a kilometer on a side, or 10 km for p-waves. There used to be an array operated by SLU to track hurricanes, since they produce large 3 to 6 second microseisms. But the azimuth was determined by phase coherence across the array to get a direction to the source. Several such arrays could locate hurricanes as they approached the coast. Maybe a better plan would be to link up the Denver area PSN stations into an array. Another way we guess at teleseismic locations is by determining the distance using S-P times, then consulting a great circle map of the world centered on us, with distances drawn in degrees. If an event is 35 degrees away from us, the only probable earthquake source region it could have come from is Columbia. A 50 degree distance has two possibilities, Northern Chile or the Eastern Aleutians. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: seismo triangulation Date: Tue, 20 Jan 1998 19:46:17 -0600 (CST) Raul, Seismic wave velocities are of the order of 2 to 6 km /second, depending on the wave type. So even a slow surface wave at 2000 m/sec would zip across your 200 m array in 0.1 second. Small arrays have been used for azimuthal data, but they are usually at least a kilometer on a side, or 10 km for p-waves. There used to be an array operated by SLU to track hurricanes, since they produce large 3 to 6 second microseisms. But the azimuth was determined by phase coherence across the array to get a direction to the source. Several such arrays could locate hurricanes as they approached the coast. Maybe a better plan would be to link up the Denver area PSN stations into an array. Another way we guess at teleseismic locations is by determining the distance using S-P times, then consulting a great circle map of the world centered on us, with distances drawn in degrees. If an event is 35 degrees away from us, the only probable earthquake source region it could have come from is Columbia. A 50 degree distance has two possibilities, Northern Chile or the Eastern Aleutians. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Northridge...from a long distance away Date: Tue, 20 Jan 1998 20:08:11 -0700 Walt Williams, Thank you for your story...it was a strong story of a strong quake. It was covered and pre-empted alot of regular tv programming for that day in Denver. It was not pretty watching the telecast switching from spot to spot commentary to helicopter overviews of destruction and shots of injured and the dead from it. For anyone involved...it would have been very tough, for quite some time afterwards also. Too me, any quake story is a part of all quakes and that is why we all share this interest. The human element is the most important part....all other data have a place, but subdued. Individually or together we have no control over quakes, they will occur no matter what. Interest wise, the subject will still be there no matter what also. As amateurs or otherwise, we are helpless to convey any real "help" in that type of situation. For a number of us, all we really do is watch the grams roll in. There is nothing wrong with this, as such; they are really kind of a historical message of an event, generally quite distant from the people really involved. For a number of us, even building a seismograph is quite an undertaking. Its not a simple task. So, when an individual records something, and gets excited by their results, he or she, is really expressing an elation of being able to construct something of their own, and are simply sharing their elation. I would cheer the individuals accomplishment for encouragement and at the same time...wish the bad quakes did not happen. Seismology is a kind of Jeckle & Hide atmosphere! For me that day it was a mixture of feelings. Safely here in Denver, for the most part it was being glued to the chair watching the tv...but at the same time I had to get the old seismo up and running, as it was only sporadic recording. Center the mass, unclog the ink line, put on paper, all the while keeping an ear out for breaking tv changes on the quake. I imagine alot of people where kind of doing the same thing that day, and feeling the same way, if they had a seismo. It seems strange to tell you a survivor of that quake what I felt and what I did that day. I suppose in a vague way, we were sharing the effects, one strongly, one weakly, but both concerned. The most unusal part of this bad quake series for me, was watching an aftershock actually happen on tv from a helicopter, the dust being thrown into the air and the excited newscasters chattering......while I then walked into the graph and watched it coming in...a rerun in a sense. It was strange. It did put on me a stronger feeling of the quake, than if I'd just simply recorded it. So, Walt, thanks for your story..........it was with alot of interest. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: seismo triangulation Date: Tue, 20 Jan 1998 09:56:11 -0800 Sean Thomas et al A thought: I think this would be another future PSN goal: to somehow link (be able to relate) the greater PSN stations together. We would need reasonably accurate time & instrument calibrations (by having a uniform method of performing the time and calibration check). Our locations are known already. I wish I knew more about the triangulation aspects of locating teleseismic events (spherical geometry). I reviewed HYPOLOC fortran programming code but didn't get to far. I could see the following possible occurance: A person could upload the event from various stations , compare the picked P&S arrival times from the different stations, and have an approximate Latitude & Longitudinal location calculated and printed out with a tolerance also shown. The problem is ,at least for me, visually picking both P & S is sometimes difficult on teleseismic events. I have had reasonable sucess by running a FFT on a moving window and looking for a frequency change when the S wave arrives. Barry S-T Morrissey wrote: >.... > Maybe a better plan would be to link up the Denver area PSN stations > into an array. > Is there much success at looking at the first P arrival sign to tell whether the event is coming from North or South? For me, the first P arrival can get lost in the background noise. > Another way we guess at teleseismic locations is by determining the > distance using S-P times, then consulting a great circle map of the > world centered on us, with distances drawn in degrees. If an event is > 35 degrees away from us, the only probable earthquake source region > it could have come from is Columbia. A 50 degree distance has two > possibilities, Northern Chile or the Eastern Aleutians. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Wife's idea on seismic magnets! Date: Wed, 21 Jan 1998 11:04:27 +0000 Hi everyone, With recent discussion on destruction of stereo speakers (wonderful!), Have recently fitted up a line of 4 pot magnets 'looking' at blocks of copper, (for beam period damping), so MAGNETS are on my mind . I asked my wife, (my chief designer ), what one should call a group of such magnets, (such as 'a pack of dogs'; 'a flock of geese'; 'a bunch of flowers'; 'a herd of elephants', etc etc.), and she suggested, "a FIELD of magnets!!" I LIKE IT! What a very nice description for a group of magnets, don't you think? Great. Now you can all go back to more stereo speaker destruction . (Pity we can't 'destroy' some of the sounds that come out of stereo speakers these days as well. ). Regards, Albert Noble (England). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Sci. instruments Date: Wed, 21 Jan 1998 10:22:48 -0500 Hi gang, I suspect that many in this list would appreciate an obscure item from the history of scientific instruments. In the days when Brittania ruled the waves, England was also the home o= f the best makers of instruments, especially sextants, compasses and peloruses. One of these was the Tates, Ltd.. They made very handsome instruments, especially magnetic compasses. The design and workmanship w= as really top-notch--gold plating, ivory scales, etc. Unfortunately, they never quite mastered the art of magnetizing their compass needles and sometimes their compasses exhibited errors as high as= 30 degrees. This anomaly is remembered to this very day. I suspect that all of you= have heard the maxim "He who has a Tates is lost." Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Bob Lewis Subject: Humerous "Seismic" story Date: Wed, 21 Jan 1998 09:57:44 -0800 In the '60's, I worked for Geotech at two seismological observatories, one in Vernal, Utah (the Uintah Basin Observatory) and another in Payson, Arizona (the Tonto Forest Observatory). For a while, I worked the third shift in Payson, midnight to 8:00 A.M. There was lots to do: running sine-wave calibrations on over 100 instruments, tending Helicorders, Develocorders, timing systems, tape recorders, etc. There was a note left for me one night that a new man would be coming in to help me, Great! Back then there was a Federal law that said if you were drafted and entered military service, that when your hitch was up, that your previous employer had to re-hire you in the same or an equivalent job. This was the case with the new guy. He was supposed to show up around midnight. He had not shown up by 1:00 A.M., so I forgot about it and got on about my duties. I started noticing that every once in a while, the traces would "go nuts", with wild excursions of the pens on the Helicorders. This would sometimes happen when animals would wander near some our vaults that were spread out over 100 square miles. This, however, was something different; it was showing up on many instruments all at the same time, obviously not wild critters. Racking my brain, it occurred to me that something might be wrong with the seismic amplifiers. A little background is needed at this point: back then, there were no 50-cent "jelly bean" op-amps that could be used to make seismic amplifiers, and the transistors of the day were very noisy. We used phototube amplifiers: wonderful creations that used reflecting galvanometers. The seismometer was connected to the galvo through an attenuator/damping network. A light beam reflected off a tiny mirror in the galvo, went through a splitter lens to two phototubes. The output of the phototubes in turn went into a tube-type amplifier/filter, eventually to produce a usable output. The galvos were quite sensitive to vibration themselves, so a special room was built in the back of the observatory to house them. The room had a large (20 foot square) concrete pier that went all the way down to bedrock. A hole a little larger than the pier was cut into the concrete slab of the building, isolating the pier from the normal vibrations of the building. I opened the door and flipped on the light. There, on top of the pier, surrounded by amplifiers, was our "new man", sound asleep! He had moved some of the amplifiers around to make room for himself, and his turning over in his sleep was the source of the "noise" that I was seeing! I found out the next day that before he was drafted, that he was to be terminated for exactly this, sleeping on the job. More stories if you like this one... Bob Lewis WB5FDF Amateur Radio Operator Amateur Seismologist Precision Time/Frequency Nut Clock Collector PSN Station #39 From: lahr@.................. Subject: sean@........... Date: Wed, 21 Jan 1998 10:45:11 -0700 (MST) Sean, I had to go back to Sears and Zemansky's University Physics to check on this issue. For a an object with mass M and radius, r, from the point of rotation to the center of mass, the moment of inertia, k, is not M*(r**2). If it were, then the moment of inertia would approach zero as the pivot approached the center of mass. The equivalent pendulum length, l, does follow the equation l = k/Mr. As r approaches zero, k approaches some constant non-zero value, so l approaches infinity, along with the period. Seems like this could be used as an alternative means of getting a long period instrument into a small space. JCLahr > John, > > The r of a physical pendulum is the radius from the > point of rotation to the center of mass, and the > moment of inertia is k = M*(r**2), and the period > T = 2*pi*sqrt(k/M*g*r). > > If all the mass is at the end L of the pendulum, r = L, > which is a simple pendulum, and the period T = 2*pi*sqrt(L/g). > As the center of mass moves towards the pivot, r decreases, > and the equivalent pendulum length l = k/Mr decreases. > In the simple condition that all of M is always at r, > l = k/Mr =(M*r**2)/Mr = r. So as r becomes shorter, > T also decreases toward zero. > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: sean@........... Date: Wed, 21 Jan 1998 11:51:56 -0600 Seems to me there is a flaw in this line of reasoning in that if the pivot were at the center of mass the period would be infinite BUT the system would also not be sensitive to linear movements of the earth only rotational movements. Jim Hannon lahr@.................. on 01/21/98 11:45:11 AM Please respond to psn-l@............. To: psn-l@.............. cc: (bcc: James M Hannon/CedarRapids/Collins/Rockwell) Subject: sean@........... Sean, I had to go back to Sears and Zemansky's University Physics to check on this issue. For a an object with mass M and radius, r, from the point of rotation to the center of mass, the moment of inertia, k, is not M*(r**2). If it were, then the moment of inertia would approach zero as the pivot approached the center of mass. The equivalent pendulum length, l, does follow the equation l = k/Mr. As r approaches zero, k approaches some constant non-zero value, so l approaches infinity, along with the period. Seems like this could be used as an alternative means of getting a long period instrument into a small space. JCLahr > John, > > The r of a physical pendulum is the radius from the > point of rotation to the center of mass, and the > moment of inertia is k = M*(r**2), and the period > T = 2*pi*sqrt(k/M*g*r). > > If all the mass is at the end L of the pendulum, r = L, > which is a simple pendulum, and the period T = 2*pi*sqrt(L/g). > As the center of mass moves towards the pivot, r decreases, > and the equivalent pendulum length l = k/Mr decreases. > In the simple condition that all of M is always at r, > l = k/Mr =(M*r**2)/Mr = r. So as r becomes shorter, > T also decreases toward zero. > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: sean@........... Date: Wed, 21 Jan 1998 07:43:53 -0800 John, Sean $0.02 - The moment inertia of an object about some point is the sum of the moment of inertia of the object about it's center of mass plus the mass times the distance from the pivot point to the center of mass squared. I(total)=I(cg)+m*d**2. The moment (force X distance) sensed by a quake or gravity, for that matter, would be the distance from the center of mass to the pivot point in the particular direction of force. The radius of gyration (r) would be a fictious distance from a point of rotation to a lumped mass of similar size and inertia as the mass in the system. I(total)=m*r**2 or r=sqrt(I/m) I think if one had a vertical pendulum shaped like a "T" with the pivot at the intersection if the two lines, a mass at the bottom of the "T" would be the mass subject to movement from a horizontal force but masses at the ends of the horizontal line of the "T" would not be influenced by the horizontal force but would contribute to the moment of inertia and therefore to the oscilation period of the sensor. A pivot at the center of mass of the system would not be subject to a rotational moment from an outside force by definiton. I guess it would have infinite period since it couldn't oscillate at all. Barry lahr@.................. wrote: > > Sean, > > I had to go back to Sears and Zemansky's University Physics to > check on this issue. For a an object with mass M and radius, r, > from the point of rotation to the center of mass, the moment > of inertia, k, is not M*(r**2). If it were, then the moment > of inertia would approach zero as the pivot approached the > center of mass. The equivalent pendulum length, l, does > follow the equation l = k/Mr. As r approaches zero, k > approaches some constant non-zero value, so l approaches > infinity, along with the period. > > Seems like this could be used as an alternative means of getting > a long period instrument into a small space. > > JCLahr > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: sean@........... Date: Wed, 21 Jan 1998 20:50:21 -0600 barry lotz wrote: > > John, Sean > $0.02 - > The moment inertia of an object about some point is the sum of the > moment of inertia of the object about it's center of mass plus the mass > times the distance from the pivot point to the center of mass squared. > I(total)=I(cg)+m*d**2. The moment (force X distance) sensed by a quake > or gravity, for that matter, would be the distance from the center of > mass to the pivot point in the particular direction of force. The radius > of gyration (r) would be a fictious distance from a point of rotation to > a lumped mass of similar size and inertia as the mass in the system. > I(total)=m*r**2 or r=sqrt(I/m) > I think if one had a vertical pendulum shaped like a "T" with the pivot > at the intersection if the two lines, a mass at the bottom of the "T" > would be the mass subject to movement from a horizontal force but > masses at the ends of the horizontal line of the "T" would not be > influenced by the horizontal force but would contribute to the moment of > inertia and therefore to the oscilation period of the sensor. > A pivot at the center of mass of the system would not be subject to a > rotational moment from an outside force by definiton. I guess it would > have infinite period since it couldn't oscillate at all. > Barry > Barry, I think you are forgetting one thing in the seismograph the force on the mass due to the earth's movement is applied by the pivot, nothing else is connected to the earth. The idea of the seismograph is that the mass stays put at least in the direction of sensitivity and the earth moves. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: sean@........... Date: Wed, 21 Jan 1998 23:32:53 -0700 (MST) On Wed, 21 Jan 1998 lahr@.................. wrote: > I had to go back to Sears and Zemansky's University Physics to > check on this issue. For a an object with mass M and radius, r, > from the point of rotation to the center of mass, the moment > of inertia, k, is not M*(r**2). If it were, then the moment > of inertia would approach zero as the pivot approached the > center of mass. The equivalent pendulum length, l, does > follow the equation l = k/Mr. As r approaches zero, k > approaches some constant non-zero value, so l approaches > infinity, along with the period. I am not sure of the context of this discussion, but the moment of inertia IS Mr^2. Indeed the moment does approach zero as r does, this follows from the whole idea of the moment of inertia... Even with this though, I have seen good derivations using the concept of the radius of gyration calculated from the moment of inertia... ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: sean@........... Date: Wed, 21 Jan 1998 11:51:25 -0800 Hi Jim I agree. My point was that the movement of a sensor was due to the distance from the pivot to the center of gravity of the mass perpendicular to the direction of motion. If the CG aligns with the pivot there wouldn't be movement. I think one could increase to rotational inertia of a sensor ,and hence the period, by strategicly locating the mass(s) with respect to the direction of motion desired. Barry Jim Hannon wrote: > > I think you are forgetting one thing in the seismograph the force on the > mass due to the earth's movement is applied by the pivot, nothing else > is connected to the earth. The idea of the seismograph is that the mass > stays put at least in the direction of sensitivity and the earth moves. > -- > Jim Hannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Charlie Rond Subject: Re: Wife's idea on seismic magnets! Date: Thu, 22 Jan 1998 01:58:34 -0600 Albert, >I asked my wife, (my chief designer ), what one should call a group >of such magnets, (such as 'a pack of dogs'; 'a flock of geese'; >'a bunch of flowers'; 'a herd of elephants', etc etc.), and she >suggested, "a FIELD of magnets!!" I LIKE IT! What a very nice >description for a group of magnets, don't you think? Great. Clever woman there! Makes me wonder what her estimate would be of a stone of geologists, or a period of seismic waves, or a ring of geophones? Charlie Rond -\/\--Public Seismic Network-Memphis rond@................ (901) 360-0302 [ free BBS ] http://gandlf.ceri.memphis.edu/~rond http://gandlf.ceri.memphis.edu/~rond/psn _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roseberry Subject: Re: Sci. instruments Date: Thu, 22 Jan 1998 06:06:08 -0600 Mr. Barns: Yes, I do appreciate the historical note; thanks for the post. Do you remember the TV series (and book) "Connections"? Professor Burke also appreciates an historical perspective -- seeking to fill-in the answer to "how we got here". Regards, Michael J. Roseberry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Walt Williams" Subject: A Lunchpail: Best Story Date: Thu, 22 Jan 1998 10:11:18 +0000 >Hello All, >A couple of years ago, I 'felt' an earthquake...... <--- Deletia ---> >...This event was called the Northridge Quake, (LA suburb, >California, USA). >Every house within seventy five miles suffered at least $20,000 US >Dollars damage. Oops, I meant twenty five miles, and it is mostly a personal opinion, derived by driving around in an automobile and looking at damaged structures over a period of six months after the quake. Best Regards, Walt Williams, 98.01.21 dfheli@.............. Canoga Park, (LA suburb), California USA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: STM-8 spring stop questions Date: Thu, 22 Jan 1998 11:16:49 -0700 Sean, This is in regard to your main spring..... Am trying to judge via your photos...it looks like on the photos, that you use 2 single point "stops" to rest the end of the springs on each end, these are maybe raised edges or perhaps rivets; anyway....is the 2 point stops, preferred? The reason I'am asking, is that it occured to me that if a person uses these PC card holders with slotted groves, that they could serve the same purpose, but that the contact would be over the width of the edge instead of at 2 small points. The depth of printed circuit card holders is maybe 1/16"...and the slot width is about the same....much greater than the thickness of the spring. Most printed circuit card holders are made of plastic (which could deform) and some are metal aluminum. The present one I have is plastic, but with a aluminum "L" back bracket supporting it for the length. Any thoughts? Another though that I have, is that with the holes on one side, it could be possible to attach a wire for a anchor post to the base plate, as a safety restrain in case of "launch". I imagine it may have to be delicately manuevered to not interfere with spring action. The spring itself appears to be blue tempered, there are silver metal varietys on the market, but these seem to have a real possibility of the metal retaining the bent shape or even developing kinks. The blue tempered are much better that you use. The above stuff may have been covered before...I just don't recall it. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Clark Wockner Subject: neic Date: Thu, 22 Jan 1998 12:20:08 -0800 Hi Gang, Does anyone know why the Neic reports are more than 24 hours old and not being updated regulary. Clark _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: STM-8 Mast stack question Date: Thu, 22 Jan 1998 14:35:18 -0700 Sean, Wished that I'd have remembered this earlier....anyway this regards the stacked square members of the mast. Are they 1" square or 1 & 1/4" or ? Am gathering parts, and the answer would help determine and accelerate construction with reference to your photos, for the general associated other parts placement. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: increasing the period: Date: Thu, 22 Jan 1998 18:51:51 -0600 (CST) Barry, Jim, and all; Now is the time to bring up my favorite subject, namely that with VBB feedback, any reasonable period can be achieved from a 1 to 2 second mechanical sensor that has a mass that is not going to challenge our resources for suspensions or springs. Not that period-lengthening masses haven't been used. We have a set of Russian LP sensors that have chrome-plated masses sticking out all over (aka designed by a committee) to lengthen the period. Their expressions for effective pendulum length are a nightmare. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: moment of inertia Date: Thu, 22 Jan 1998 19:00:02 -0600 (CST) John, I think you misread your Sears-Zemansky. And I have mixed up the nomenclature. I have used k for the moment of inertia following the conventions that Kisslinger uses.... sort of: He actually uses K for moment and k for spring constants. Moment of inertia is usually "I". Sears-Zemansky defines moment of inertia as the summation of the masses of all the particles multiplied by the square of all their distances from the axis of rotation. or I = summation(M*(r**2)). I is evaluated (using integral calculus) as the intergal of all the incremental masses times the square of their radial distances from the axis. (it uses "k" for the "radius of gyration"; k = sqrt(I/m)) For the ideal situation of a dimensionless point mass, the moment of inertia I = M*(r**2). If r goes to zero, the moment is zero, since there is no rotation. The units if I are always mass times length squared. In the real world, not all the mass is at the same radius from the axis, so evaluating the integral gives some interesting results, like the I of a slender rod rotated about one end is 1/3*m*L**2, but only 1/12*m*L**2 if it is rotated about its center, which is why it is easier to twirl a baton than to swing a bat. Even a solid sphere has an interesting I, namely 2/5*m*r**2. If the r of a physical pendulum is the radius from the point of rotation to the center of mass, the total moment of inertia is I = Im + M*(r**2), where Im is the moment of inertia about the center of mass. For our slender rod example with the pivot at one end, the Im = 1/12*M*L**2; then r =1/2*L, or r**2 = 1/4*L**2 so I = 1/12*M*L**2 + 1/4*M*L**2 which equals 1/3*M*L**2, as shown above. So the moment of inertia of any complex object can be determined. Whatever it is, the period T = 2*pi*sqrt(I/M*g*r). If all the mass is at the end L of the pendulum, r = L, which is a simple pendulum, and the period T = 2*pi*sqrt(L/g). As the center of mass moves towards the pivot, r decreases, and the equivalent pendulum length l = I/Mr decreases. Note that I has dimensions of M and r**2. In the simple condition that all of M is always at r, l = I/Mr =(M*r**2)/Mr = r. So as r becomes shorter, T also decreases toward zero. This is obvious when a weight is dangled on a string; as the string is made shorter, the ticks are faster. At about 10 inches, the period is one second. A grandfather clock needs a 39 inch pendulum for a 2 second tick. The original question posed was whether adding mass at the end of the pendulum will increase the period. It does to the extent that I increases, up to the point that virtually all the mass is at the free end and r = L, and the maximum period of a simple pendulum is obtained. If mass is added elsewhere to the pendulum, the total moment and period can be calculated. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: moment of inertia Date: Thu, 22 Jan 1998 19:00:02 -0600 (CST) John, I think you misread your Sears-Zemansky. And I have mixed up the nomenclature. I have used k for the moment of inertia following the conventions that Kisslinger uses.... sort of: He actually uses K for moment and k for spring constants. Moment of inertia is usually "I". Sears-Zemansky defines moment of inertia as the summation of the masses of all the particles multiplied by the square of all their distances from the axis of rotation. or I = summation(M*(r**2)). I is evaluated (using integral calculus) as the intergal of all the incremental masses times the square of their radial distances from the axis. (it uses "k" for the "radius of gyration"; k = sqrt(I/m)) For the ideal situation of a dimensionless point mass, the moment of inertia I = M*(r**2). If r goes to zero, the moment is zero, since there is no rotation. The units if I are always mass times length squared. In the real world, not all the mass is at the same radius from the axis, so evaluating the integral gives some interesting results, like the I of a slender rod rotated about one end is 1/3*m*L**2, but only 1/12*m*L**2 if it is rotated about its center, which is why it is easier to twirl a baton than to swing a bat. Even a solid sphere has an interesting I, namely 2/5*m*r**2. If the r of a physical pendulum is the radius from the point of rotation to the center of mass, the total moment of inertia is I = Im + M*(r**2), where Im is the moment of inertia about the center of mass. For our slender rod example with the pivot at one end, the Im = 1/12*M*L**2; then r =1/2*L, or r**2 = 1/4*L**2 so I = 1/12*M*L**2 + 1/4*M*L**2 which equals 1/3*M*L**2, as shown above. So the moment of inertia of any complex object can be determined. Whatever it is, the period T = 2*pi*sqrt(I/M*g*r). If all the mass is at the end L of the pendulum, r = L, which is a simple pendulum, and the period T = 2*pi*sqrt(L/g). As the center of mass moves towards the pivot, r decreases, and the equivalent pendulum length l = I/Mr decreases. Note that I has dimensions of M and r**2. In the simple condition that all of M is always at r, l = I/Mr =(M*r**2)/Mr = r. So as r becomes shorter, T also decreases toward zero. This is obvious when a weight is dangled on a string; as the string is made shorter, the ticks are faster. At about 10 inches, the period is one second. A grandfather clock needs a 39 inch pendulum for a 2 second tick. The original question posed was whether adding mass at the end of the pendulum will increase the period. It does to the extent that I increases, up to the point that virtually all the mass is at the free end and r = L, and the maximum period of a simple pendulum is obtained. If mass is added elsewhere to the pendulum, the total moment and period can be calculated. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Lehman drift Date: Thu, 22 Jan 1998 07:05:02 -0800 Hi all I tried an experiment last night. I have a 12" Lehman with a coil and displacement measurng device. I used the coil to induce a restoring force to the boom and the displacement measurement to measure the boom movement from center. I ran the displacement output thru a RC single pole lowpass filter( r=1 meg, c= 47u, cutoff freq=295 sec). This I ran to the noninverting input of an opamp(w/again of 3) ,thru a 3k resistor, thru the coil and to ground. As I slowly moved the leveling screws the boom remained centered but the normal oscilations(1-10sec periods) seemed unaffected. When I unpluged the coil the boom drifted and hit the stop due to the tilt I induced. Thus I seems possible to use a displacement sensor with coil to eliminate boom drift without affecting the signal wanted. I will try this installed and keep you posted. I tried to keep the gain low to prevent oscillations. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: STM-8 Mast stack question Date: Thu, 22 Jan 1998 20:15:12 -0600 (CST) Meredith, Unfortunately, I did it differetly on the Beta instrument: I used two hollow square tubes with 1/2" aluminum bolts inside mounted vertically from base to support the fixed side of the hinges. Actually, almost anything massive will do. I want to try stainless channel or tube with SS bolts, because steel has about half the thermal coefficient as aluminum, and the current design has a negative thermal behavior (the boom goes up as the temperture decreases). Regarding the details of the spring mounting: it is almost impossible to describe, although I am working on it. I will try to work on it this weekend and post it. I really need to do a good technical drawing of the details. FYI: the brass rods are 3/16"; the screws are 4-40 stainless. For the Beta unit, I made a clamp across the whole end of the leaf spring with 3/16" id square brass tubing with a 0.010 slit along one corner, and a flat-filed brass rod inside to clamp the spring with the 4-40 screws in tapped holes. The extensions of this rod are slit (0.010) to accommodate the flexures at the lower end. The upper end rests on a curved glass bearing surface. I still don't have a good solution for damping the high frequency vibration of the leaf spring itself. I have never considered anything other than the hardened tempered spring. I think that anything that does not fully recover from all but the most severe bending will sag with age. PS: Would you be interestested if I were to rescan the photos to a larger format that might take some time to download ? regards, Sean-thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Stainless Steel Date: Thu, 22 Jan 1998 20:55:29 -0600 Sean, Speaking of using stainless steel for seismo have you heard of http://www.shapirosupply.com/metal.html They are in St Louis and sell all sorts of metal stock. Are magnetic fields such a big problem that you can't use plain old steel? -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Katharine Kramer Subject: Re: increasing the period: Date: Thu, 22 Jan 1998 19:09:22 -0800 (PST) On Thu, 22 Jan 1998, S-T Morrissey wrote: > Barry, Jim, and all; > Now is the time to bring up my favorite subject, namely that > with VBB feedback, any reasonable period can be achieved from > a 1 to 2 second mechanical sensor that has a mass that is not > going to challenge our resources for suspensions or springs. > > Not that period-lengthening masses haven't been used. We have > a set of Russian LP sensors that have chrome-plated masses > sticking out all over (aka designed by a committee) to lengthen > the period. Their expressions for effective pendulum length are > a nightmare. > > 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 > PLEASE DELETE ME FROM THIS MAILING LIST...kramerk@............ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Katharine Kramer Subject: Re: moment of inertia Date: Thu, 22 Jan 1998 19:10:36 -0800 (PST) On Thu, 22 Jan 1998, S-T Morrissey wrote: > John, > > I think you misread your Sears-Zemansky. And I have > mixed up the nomenclature. I have used k for the > moment of inertia following the conventions that Kisslinger > uses.... sort of: He actually uses K for moment and k for > spring constants. Moment of inertia is usually "I". > Sears-Zemansky defines moment of inertia as the > summation of the masses of all the particles multiplied > by the square of all their distances from the axis of > rotation. or I = summation(M*(r**2)). I is evaluated (using > integral calculus) as the intergal of all the incremental > masses times the square of their radial distances from the axis. > (it uses "k" for the "radius of gyration"; k = sqrt(I/m)) > > For the ideal situation of a dimensionless point mass, > the moment of inertia I = M*(r**2). If r goes to zero, > the moment is zero, since there is no rotation. > The units if I are always mass times length squared. > > In the real world, not all the mass is at the same > radius from the axis, so evaluating the integral gives > some interesting results, like the I of a slender rod > rotated about one end is 1/3*m*L**2, but only 1/12*m*L**2 > if it is rotated about its center, which is why it is > easier to twirl a baton than to swing a bat. Even a solid > sphere has an interesting I, namely 2/5*m*r**2. > > If the r of a physical pendulum is the radius from the > point of rotation to the center of mass, the total > moment of inertia is I = Im + M*(r**2), where Im is > the moment of inertia about the center of mass. > For our slender rod example with the pivot at one end, > the Im = 1/12*M*L**2; then r =1/2*L, or r**2 = 1/4*L**2 > so I = 1/12*M*L**2 + 1/4*M*L**2 which equals 1/3*M*L**2, > as shown above. So the moment of inertia of any complex > object can be determined. Whatever it is, the period > T = 2*pi*sqrt(I/M*g*r). > > If all the mass is at the end L of the pendulum, r = L, > which is a simple pendulum, and the period T = 2*pi*sqrt(L/g). > As the center of mass moves towards the pivot, r decreases, > and the equivalent pendulum length l = I/Mr decreases. > Note that I has dimensions of M and r**2. > In the simple condition that all of M is always at r, > l = I/Mr =(M*r**2)/Mr = r. So as r becomes shorter, > T also decreases toward zero. This is obvious when a > weight is dangled on a string; as the string is made > shorter, the ticks are faster. At about 10 inches, the > period is one second. A grandfather clock needs a 39 inch > pendulum for a 2 second tick. > > The original question posed was whether adding mass at the end > of the pendulum will increase the period. It does to the > extent that I increases, up to the point that virtually all > the mass is at the free end and r = L, and the maximum period > of a simple pendulum is obtained. If mass is added elsewhere > to the pendulum, the total moment and period can be calculated. > > > 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 > PLEASE REMOVE ME FROM THIS MAILING LIST...kramerk@............ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: kathy mortensen Subject: springs & speakers Date: Thu, 22 Jan 1998 19:51:52 -0700 Sean or anyone, I forgot who asked about the different types of spring material but I noticed while shopping for material for my new stm-8 that some stores have two types of steel texturing blades identified as "blue" steel and "stainless" steel !! The stainless seems to be as flexible as the blue. Maybe this is what they were asking about? Any comments or observations?? Next, I noticed in my travels some 8 and 10 inch speakers, 4 ohms, 175 to 230 watts for about $15.00 to $20.00. Will the higher wattage help with using a larger mass? Is there any advantage in using 4 or 8 ohms? Will staying with the Radio Shack speaker help us to be more compatable or perhaps easier to work with etc. Any reason why we can't place the coil on the frame? We could eliminate the wiring across the hinges if we mount the magnet on the boom! (hmmmm, -- speaking to myself -- maybe I better do some math!! Is the magnet too heavy??) Thanks in advance for your time and experience SKM (Stephen) Pilot Hill Ca. USA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: STM-8 spring flexures mounting Date: Thu, 22 Jan 1998 21:09:07 -0700 Sean, Thanks for your reply on the mast and flexures. It clarifyed alot. So....out to the electronics stash goes the pc card guides idea. I shall be anxiously awaiting your technical drawings of the details least I again misjudge the mechanisms per your msg post. The drawing would likely be better than a photo enlarging due to shade, reflection, color variations on a photo, per my received PC screen viewing. Thanks for the reply, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: Re: STM-8 Mast stack question Date: Thu, 22 Jan 1998 23:34:16 EST SEAN-THOMAS: Yes, it would be helpful if you could rescan your photos, especially of the spring and boom areas in larger formats. For me it would be well worth the additional download time. Jim Allen Cerritos, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: Stainless Steel Date: Thu, 22 Jan 1998 23:30:16 -0600 (CST) Jim, I use stainless hardware for everything. That way I can buy it in quantity cheaply (Service Supply Co.), and only have one set to worry about: #2 thru 3/8, 1/4" thru 2", or so, and all the nuts, (bought in 1k bags), etc. It isn't that much more expensive than plated steel, and is always suitable for any application, and I never even have to worry about magnetic problems. I recomment the practice. McMaster supply or Grainger are also good sources. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: springs & speakers Date: Thu, 22 Jan 1998 23:44:06 -0600 (CST) Stephen, There is room for lots of experimentation here, and no magic formulas. I would suspect that the SS spring is inherently weaker than the hardened one I use. As for speakers, I felt that I was pushing the envelope with the one I selected, which has TWO 4-ohm coils and a 20 ounce magnet. I don't know what sort of generator or force constant one would get with a 4-ohm coil. It is about 13 N/A for the dual coil. The mass of the magnet IS important here also. I think that constants much less than 10 will be difficult to work with. A problem with a moving magnet and fixed coils is that the magnet will detect everything magnetic, from your pocket knife to cars and geomagnetic storms. It was tried with early seismometers, but required massive shielding. Even the elegant STS-1 sensor uses magnetic shields because its' leaf spring is susceptable to stray fields. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: Lehman drift Date: Thu, 22 Jan 1998 23:59:21 -0600 (CST) Barry Way to go!! Now go the rest of the way. You just made an integrator, and have an RI of 3k (a bit low for VBB). Now all you have to do is connect the differential capacitor and the proportional resistor from the output of your displacement detector to the coil and have a full VBB feedback, at which point the displacement output is the broadband velocity signal. Do you have MATHCAD to model your response? I have put a copy of the original mathcad worksheet at: http://www.eas.slu.edu/People/STMorrissey/etc_export/tstvbb08.mcd (I think thats' right; I can't check it from this window; if its wrong, I'll let you know). Download it and open it with standard Mathcad and then substitute your parameters to see how to best select your feedback components. Now we need some quakes; we have a hugh 6-second microseism storm going in the east; they are comming in here at 40mv P-P, above a nornal noise floor of about 1mv. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Charlie Rond Subject: Quake? Date: Fri, 23 Jan 1998 00:26:21 -0600 Looks like a big one 6+ UTC. Anyone pinned it down? Charlie Rond -\/\--Public Seismic Network-Memphis rond@................ (901) 360-0302 [ free BBS ] http://gandlf.ceri.memphis.edu/~rond http://gandlf.ceri.memphis.edu/~rond/psn _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: Quake? Date: Thu, 22 Jan 1998 22:40:44 -0800 Nothing here.... -Larry At 12:26 AM 1/23/98 -0600, Charlie wrote: >Looks like a big one 6+ UTC. Anyone pinned it down? > > > Charlie Rond -\/\--Public Seismic Network-Memphis _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Charlie Rond Subject: Re: Quake? Date: Fri, 23 Jan 1998 01:26:16 -0600 Larry, >Nothing here.... We're getting a lot of wind here...wonder if it that's it? It's been so quiet lately, I may have over-reacted. Thanks for the reply. Charlie Rond -\/\--Public Seismic Network-Memphis rond@................ (901) 360-0302 [ free BBS ] http://gandlf.ceri.memphis.edu/~rond http://gandlf.ceri.memphis.edu/~rond/psn _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Quake? Date: Fri, 23 Jan 1998 21:55:29 +1200 >We're getting a lot of wind here...wonder if it that's it? It's been so >quiet lately, I may have over-reacted. > >Thanks for the reply. > Charlie Rond -\/\--Public Seismic Network-Memphis Charlie (and all others) if u ever need to confirm if u have recorded a quake there is the best site to do so it is a www live seismic server site and as recordings from seismographs from many locations around the world. I make contineous use of this site. it just cannot be bypassed the seismograms are updated every 30 minutes. http://aslwww.cr.usgs.gov/Seismic_Data/heli.htm I notice over the last 4-6 hrs that the background noise has increased sharply on the Albuquerque, New Mexico, USA and the Tucson, Arizona recorders. 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: Charlie Rond Subject: Re: Quake? Date: Fri, 23 Jan 1998 03:38:46 -0600 Dave, >Charlie (and all others) if u ever need to confirm if u have recorded a >quake there is the best site to do so it is a www live seismic server site >and as recordings from seismographs from many locations around the world. >I make contineous use of this site. it just cannot be bypassed the >seismograms are updated every 30 minutes. > >http://aslwww.cr.usgs.gov/Seismic_Data/heli.htm > > >I notice over the last 4-6 hrs that the background noise has increased >sharply on the Albuquerque, New Mexico, USA and the Tucson, Arizona >recorders. Thanks very much, that's what I've been looking for! Tried the NBC live cam, (www.knbc4la.com/seismo/) but apparently it's no longer operative. Charlie Rond -\/\--Public Seismic Network-Memphis rond@................ (901) 360-0302 [ free BBS ] http://gandlf.ceri.memphis.edu/~rond http://gandlf.ceri.memphis.edu/~rond/psn _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: Lehman drift..hor beams Date: Fri, 23 Jan 1998 12:56:33 +0000 Hi Barry, I am using PC to 'average' displacement readings and o/p a correction signal to a 12bit D/A and to tiny coil. A op amp diff comparator gives pos or neg volts to coil depending on which way beam is veering. PC averages for 15 secs, sends new info, and then waits for further 15 secs before new averaging begins. Its quite uncanny to see beams recentred THEMSELVES, isn't it? Beam drift is worst at long periods because any pier /earth tilt moves the top of the 'long pendulum equivalence', thro' a greater distance, hence beam moves over a greater distance. I find that +- 1 volt is sufficient to push/pull beam about 1/4" either way, so this is sufficient. A bonus is that the correction numbers from PC are a reading of earth tilt and can be plotted as such by PC on VDU !! Watch the earth tilt day by day . Regards, Albert Noble (England). barry lotz wrote: > Hi all > I tried an experiment last night. I have a 12" Lehman with a coil and > displacement measurng device. I used the coil to induce a restoring > force to the boom and the displacement measurement to measure the boom > movement from center. I ran the displacement output thru a RC single > pole lowpass filter( r=1 meg, c= 47u, cutoff freq=295 sec). This I ran > to the noninverting input of an opamp(w/again of 3) ,thru a 3k resistor, > thru the coil and to ground. As I slowly moved the leveling screws the > boom remained centered but the normal oscilations(1-10sec periods) > seemed unaffected. When I unpluged the coil the boom drifted and hit the > stop due to the tilt I induced. Thus I seems possible to use a > displacement sensor with coil to eliminate boom drift without affecting > the signal wanted. I will try this installed and keep you posted. I > tried to keep the gain low to prevent oscillations. > Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Seisguy Subject: Re: Quake? Date: Fri, 23 Jan 1998 09:46:03 EST In a message dated 98-01-23 01:30:12 EST, you write: > Subj: Quake? > Date: 98-01-23 01:30:12 EST > From: rond@................ (Charlie Rond) > Reply-to: psn-l@............. (PSN-L Mailing List) > To: PSN-L@............. > > Looks like a big one 6+ UTC. Anyone pinned it down? > > How about this M5.7, could this have been what you recorded? Mike Northridge ------------------------------------------------------------------------------ ---------------------------------------- Subj: USGS Earthquake report Date: 98-01-23 07:24:40 EST From: info@................... (USGS Geologic Division) To: info@................... (USGS Geologic Division) Magnitude 5.7 earthquake near FOX ISLANDS, ALEUTIAN ISLANDS 52.71N, 168.76W depth 33.0km Fri Jan 23 09:20:07 1998 GMT An earthquake has occurred. Following is information provided by the National Earthquake Information Service of the USGS. This information is preliminary and subject to correction. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Re: FM transmission Date: Fri, 23 Jan 1998 08:40:14 -0800 >Norman, >Just to be sure I went and back and read the FCC rules again. 1: >Telemetry is specifically permitted by the rules. 2: Broadcasting is >transmitting to nonamateurs or transmitting without a specific >recipient. Since in this case one would be transmitting to yourself a >licensed amateur it would not be broadcasting. There are some rules >about control of an unattened transmitter but there are ways of meeting >those requirements. > >Jim Hannon >http://soli.inav.net/~jmhannon/ >42,11.90N 91,39.26W >WB0TXL Well in that case maybe I will do that. I think though you would have to have the tx ID. Yes? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: FM transmission Date: Fri, 23 Jan 1998 11:10:11 -0600 Yes you do have to have an appropriate ID in your transmission. Jim Hannon normd@............. on 01/23/98 10:40:14 AM Please respond to psn-l@............. To: psn-l@............. cc: (bcc: James M Hannon/CedarRapids/Collins/Rockwell) Subject: Re: FM transmission Well in that case maybe I will do that. I think though you would have to have the tx ID. Yes? _____________________________________________________________________ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: STM-8 VRDT xfmr Date: Fri, 23 Jan 1998 17:12:05 -0700 Sean, With reference to your vrdt transformers conversion: Mouser Electronics on web at http://mouser.com/info.html Does not list a TM0019....the nearest 3, I can figure is : 42TM009 with a primary impedance of 500 ohm CT and a secondary of 500 CT and with a pri resistance of 50 ohms and secondary of 40 ohms. 42TL009 pri 500CT sec 500CT with pri R of 40, sec R of 38 42TU500 pri 500CT sec 500CT with pri R of 35, sec R of 28 Which one would be best for the application? Mouser can be downloaded (large file) or subscribed to (mail catalog request) via net location. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: STM-8 VRDT xfmr Date: Fri, 23 Jan 1998 18:52:29 -0600 (CST) Meredith, My mistake; the documentation is recycled from another project. For the VRDT I am using the TL021 miniature 4k to 500 ohms, with a total resistance (primary + secondary) of about 200 ohms. I measure the R of several and try to match them in pairs. I use the center laminate of the larger TM009 for the sensing vane, or you can get a transformer grab bag from radio shack and dismantle one for it. The sensing vane is supported by one edge by soldering it to a length of 1/16" brass rod (don't be tempted to use a STEEL paperclip). After it is all assembled, use a tape-head demagnetizer (or soldergun) to demagnetize the vane and the cores. Regards, Sean-thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Mariposa Tribune Subject: Re: FM transmission Date: Fri, 23 Jan 1998 17:08:43 -0800 At 11:10 AM 1/23/98 -0600, you wrote: > > > > >Yes you do have to have an appropriate ID in your transmission. > >Jim Hannon > > > > >normd@............. on 01/23/98 10:40:14 AM > >Please respond to psn-l@............. > >To: psn-l@............. >cc: (bcc: James M Hannon/CedarRapids/Collins/Rockwell) >Subject: Re: FM transmission > > > > > > > > Well in that case maybe I will do that. I think though you would have to >have the tx ID. Yes? > > >_____________________________________________________________________ > > > > > > > > >_____________________________________________________________________ > >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: FM transmission Date: Fri, 23 Jan 1998 19:06:35 -0800 Something worth considering is the use of packet radio in amateur service. If the data collected is already in digital format, this could be a good way to go. Packet has the advantage that it is error correcting... James M Hannon wrote: > > Yes you do have to have an appropriate ID in your transmission. > > Jim Hannon > > normd@............. on 01/23/98 10:40:14 AM > > Please respond to psn-l@............. > > To: psn-l@............. > cc: (bcc: James M Hannon/CedarRapids/Collins/Rockwell) > Subject: Re: FM transmission > > Well in that case maybe I will do that. I think though you would have to > have the tx ID. Yes? > > _____________________________________________________________________ > > _____________________________________________________________________ > > 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: ACole65464 Subject: Re: Quake? Date: Fri, 23 Jan 1998 23:24:39 EST Dave, The live seismic server has become one of my favourite sites also. Note that the velocity signals that are displayed from the different sites are filtered with software with a band pass of .001 Hz up to .04 Hz. That's why you see so little noise. Go to the IRIS home page and go to their map. You can click on some of the sites that the live seismic server displays data from. A lot of important instrument data can be acessed about the instruments (site noise etc) and some have photos taken of the site. The south pole site says its seismometers are mounted on a metal plate attached directly to a wooden floor on top of the ice. The IRIS site has links to the NEIC's QED and this data is down loaded quicker to my computer than the NEIC's page. Check it out. Allan Coleman _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: STM-8 phosphor bronze springs Date: Fri, 23 Jan 1998 22:18:18 -0700 Sean, Boy....I imagine you are saying to yourself...Not Again! But here in Denver, the hardest part to find is.........the bronze springs. Every place stocks bronze weatherstripping, but...they are the channeled variety....not the desired flat springs, or even partially flat enough to use some of whats available on the coils. I'am aware of McMaster-Carr catalog on the net, and that they do have the desired strips. 6" wide X 8ft long, ..005" thick $17.41 ea roll. Stock # 9052K11. The price is cheaper for the quanity you get compared to the store ~$7-8 range. Uhhh, maybe good for 50 seismos. Can an individual hammer & flatten these formed strips, and still successfully benefit from them? I would think they would lose some desired properties this way. Can machinest type steel shim stock gauges (spring variety) replace bronze? Or....is there another known substitute not brought up? I will get some one way or the other. My concern is that there maybe others who can't obtain the flat bronze in their locality's and may be faced with the same problem. My secret stash here calls for remodeling the front door frame with their "old" flat 40 year old weatherstripping with New wrinkley stuff. Tell your wifes that story....if you have some flat stuff on your door frame & can't get it locally. Guessing here...perhaps door shops may have excess flat stock......the older the company the better. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: STM-8 phosphor bronze springs Date: Sat, 24 Jan 1998 00:20:29 -0600 (CST) Meredith, I happen to have a large (20lbs? ) roll of the bronze material that is 3/4" wide which I used on the prototype and the vertical hinge of the horizontal. But I have also cut out the flat center strip of the embossed weatherstripping material; it is about 3/8" wide, which is what I used on the second instrument. It is not as elastic as the phosphor bronze, but we really don't want a major spring effect from the hinges. They need to be "springy" enough that large motions of the boom that happen when the seis is being worked on don't impart a permanent bend in the hinge, but they cannot be so strong that they control the mechanical period. You can also get packs of brass, bronze, and copper shim stock at the hobby metals display of a True-Value hardware store. (where you can also get the brass rod and square tube for mounting the leaf spring and flexures.) There is really no problem in using thin steel or hardened aluminum material. Take apart the holder for an emptied pack of Polaroid film; there is a steel spring leaf assembly that can be cut up. The material might be too strong, though. (warning : don't short out the flatpack battery it contains) This is one of the main advantages of a fully fedback seis, namely that the feedback determines most of the response. as long as the mechanical suspension of the mass is very weak compared to the feedback force, which is evident when it has a mechanical period of a second or more. Using half the hinge width in my second instrument reduced the hinge restoring force such that I could get a period about 40% longer with a boom 30% shorter. It still allowed enough flat area for mounting them with epoxy. I will get your photos of the LP vertical next week, I hope. I can send you some of the material I use. Eventually we may want to "pool" some materials, such as you found at McMaster supply. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Al Allworth Subject: Re: STM-8 phosphor bronze springs Date: Fri, 23 Jan 1998 22:35:32 -0800 At 10:18 PM 1/23/98 -0700, you wrote: >Sean, > >Boy....I imagine you are saying to yourself...Not Again! But >here in Denver, the hardest part to find is.........the bronze >springs. Brass and stainless shim stock is available from machine shop supply places and some of the larger hardware stores. Thicknesses run from .001 on up to ..030 or so. It is usually 6 in. wide and I used to buy it in Pasadena for $1.00 per foot for brass and $1.50 for the stainless. Avoid the hardened steel variety, it is magnetic. ____________________________________________________________________________ Al Allworth, Gold Beach, OR aallworth@........ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: FM transmission Date: Sat, 24 Jan 1998 09:02:48 -0600 bob ogburn wrote: > > Something worth considering is the use of packet radio in amateur > service. > If the data collected is already in digital format, this could be a good > way to go. Packet has the advantage that it is error correcting... > Bob, I completely agree. Not only does it have error correction and detection but all the hardware and most of the software to do it is avaliable without having to reinvent the wheel. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Re: STM-8 phosphor bronze springs Date: Sat, 24 Jan 1998 10:12:07 -0700 Sean, Thanks for the bronze reply, that did the trick as far as overall understanding...of its use and importance with the design. The part about the size of the hinges having a bearing on overall seismo size and period and possible reduction...says alot. I would think that phosphor bronze would be the material of durability & long time use over other metals with their fatique historys. I would be all for any kind of "critical materials" seismograph pool. Phosphor bronze seems to be number one....the curved glass you use in the upper dry wall knife flexure...maybe...number two, dunno....as that.... has yet to be published. Presumed concave? I can wait on that.... (twitch). OK on the LP stuff, that will be very interesting. Yes, I would be interested in a scrap of bronze if possible...the wife knows all about my door plans and is crosseyed. Another possible source may not pan out. Have yet to check McMaster-Carr to see even if they sell to individuals....or have minimum orders...will check today. Thanks, Meredith Lamb .. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Seismic Engineering Codes Date: Sat, 24 Jan 1998 13:04:25 -0700 (MST) Hello All, I was wondering about something I have seen recurring in discussions about earthquake "proofing" buildings. This is the fact that they all seem to assume that the frequency of an earthquake is set at 1 Hz! I know that near the epicenter the dominant shaking seems to be near this value, but I think it is a mistake to assume this frequency for all cases. Am I wrong about this??? ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: Seismic Engineering Codes Date: Sat, 24 Jan 1998 01:58:35 -0800 Hi John Most basic structural seismic design is based on a response spectrum from select earthquakes "El Centro 19.. etc". The response spectrum is the response of a single degree of freedom system(lumped mass) to a particular earthquake. If one knows the periods of the modes for a structure then one can superimpose the modal responses to get the actual response. In more elaborate designs the earth-structure interaction is taken into account and a time history response of the structure is obtained for an ( or several) historical events. The bottom line is that many frequencies can be considered in the design,the design tools are there, but which tools are used depends on the structure and economics. I hope this helps Barry John Hernlund wrote: > > Hello All, > I was wondering about something I have seen recurring in discussions > about earthquake "proofing" buildings. This is the fact that they all > seem to assume that the frequency of an earthquake is set at 1 Hz! I > know that near the epicenter the dominant shaking seems to be near this > value, but I think it is a mistake to assume this frequency for all > cases. Am I wrong about this??? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: moment of I and period Date: Sat, 24 Jan 1998 15:33:50 -0600 (CST) John, Barry, and co. I need to finish the period lengthening discussion and assure you that your ideas are fundamentally correct when we consider pendulums with more than one mass. Adding additional mass to a pendulum near the axis of rotation WILL increase the period, but not as dramatically as we would hope for. If we consider a simple pendulum (massless boom) 25cm long, it has a period of one second, independent of the weight of the mass. But lets say the mass is 500gm. The moment about the hinge is I = m*r^2, or 500*(25^2)gm*cm^2, = 312.5*10^3. If we add two additional large masses on opposite sides of the pivot (so their net torque is zero: Barrys T formation) of 1000gm, at a distance of 10 cm, their combined moments are 200*10^3. So the total moment of the pendulum is now (200 + 312.5)*10^3 gm*cm^2 = I. The reduced pendulum length is L = I/m*r. So L = 512.5*10^3/(500 * 25) = 41 cm, and the period (T = 2*pi*sqrt(L/g) ) is lenthened to 1.29 seconds. If we put the 1kgm masses farther out, like the length of the pendulum, 25 cm, the period only increases to 2.24 cm. It has more than doubled, but we now have a large contraption and heavy demands on the hinge system. We are fighting the square-root effect of increasing L. This is why period-changing auxillary masses were used just to fine-tune the period. Low-angle (to g) suspensions are much more effective in obtaining longer mechanical periods. Of course with VBB feedback, any convenient mechanical period can be used, which is especially handy for horizontal sensors whose tilt sensitivity increases withthe square of the mechanical period. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: Seismic Engineering Codes Date: Sat, 24 Jan 1998 16:17:02 -0700 (MST) > Most basic structural seismic design is based on a response spectrum > from select earthquakes "El Centro 19.. etc". The response spectrum is > the response of a single degree of freedom system(lumped mass) to a > particular earthquake. If one knows the periods of the modes for a > structure then one can superimpose the modal responses to get the actual > response. In more elaborate designs the earth-structure interaction is > taken into account and a time history response of the structure is > obtained for an ( or several) historical events. The bottom line is that > many frequencies can be considered in the design,the design tools are > there, but which tools are used depends on the structure and economics. > I hope this helps Yes, I know how this is done. If they use an actual historic quake record for that area it would probably work out IF they can cover all of the frequency ranges and keep the building's fundamental mode out of that range. For close quakes, maybe this means the taller the better due to the fact that higher frequencies are more prominent in these instances. But there are longer period waves, and it seems irresponsible to assume a main frequency of 1 Hz and consider everything under that fundamental mode safe... ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: ralvarez@........ (Raul Alvarez) Subject: Re: STM-8 phosphor bronze springs Date: Sat, 24 Jan 1998 18:32:51 -0700 (MST) Hello All, In reply to Meredith's question on getting brass stock, one source for brass shim stock is MSC. MSC carries .005 6" x 60 inches, stock 32020059 for $5.65. Page 2052 in main catalog. 1-800-645-7270 only problem is the $25 minimum order, so you may have to other needed items at the same time. BTW, as a rule of thumb, if a company accepts Visa/MC or other credit cards, they usually sell to anyone. Raul ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~ ~ ~ "My dreams are the seeds of my reality, ~ ~ nurtured in the womb of my soul" ~ ~ RJA, 1985 ~ ~ ~ ~ ~ ~ Raul J. Alvarez ~ ~ Bellvue, Colorado ~ ~ e-mail ralvarez@........ ~ ~ homepage www.frii.com/~ralvarez ~ ~ "The Renaissance Experimenter" ~ ~ experimenter in: ~ ~ Radio and Optical Astronomy, Seismology, Weather, ~ ~ Computers, Instrumentation and Neat Stuff! ~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Leaf spring period Date: Sat, 24 Jan 1998 19:35:11 -0600 To add to the discussion on period I have been fooling around with the equations in Sean's report in the part about spring constants. k=m*g/(l-l0) and k=4*pi**2*M/T**2 The first equation is a form of the standard linear spring equation F=k(l-l0) and the second equation is the relationship between the mass, spring constant and the period T=2*pi*sqrt(M/k) If we solve the first equation for the amount the spring will stretch with a mass hangning on it in normal gravity MG=k(l-l0) let l-l0 = x and solve for k=(M*G)/x substituting this into the period equation we get T=2*pi*sqrt(x/G) This is interesting because it says that no matter what the mass or spring constant if you stretch the spring a given amount you have the same period. If we figure the stretch for a period of 1 sec we get 25 cm. This is a bit big for a seismograph. So we would like some way for the amount we have to stretch the spring to be smaller. The zero length spring described in the gravimeter web page is what I call a preloaded spring, it takes some amount of force the begin to stretch the spring. The force equation for this spring becomes F=p+k(l-l0) p for prelaod. It is easy to see that if you hang a mass on this type of spring the strech will be less for a given spring k. The period is no longer independant of k and M but the overall size is smaller. Going back to the period equation T=2*pi*sqrt(M/k) one can see that to increase the period you can increase the mass or decrease k. Here is where my knowledge runs out. In the case of the leaf spring I think that k is no longer a constant but is a function of the amount the spring is compressed. Thus by playing with the amount the spring is compressed the mass and the lever arm ratio it is possible to find a place where k is small enough the give you the desired period. If I can find the time I am going to measure a drywall knife blade and plot k vs x k in this case is df/dx the rate of change of force with distance. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: Lehman drift Date: Sat, 24 Jan 1998 07:34:44 -0800 Sean Thomas I connected my vertically hanging pendulum with the speaker coil & magnet and component values which seamed to work with Mathcad. I had problems with the sensor drifting off scale. Could this be due to slight slab tilting? I thought I would be measuring velocity? I realize you would need to know my component values. Have you experienced electrical drifting of zero til it would go off scale? Barry S-T Morrissey wrote: > > Barry > Way to go!! Now go the rest of the way. You just made an integrator, > and have an RI of 3k (a bit low for VBB). Now all you have to do > is connect the differential capacitor and the proportional resistor > from the output of your displacement detector to the coil and have > a full VBB feedback, at which point the displacement output is the > broadband velocity signal. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: joke - electricity Date: Sat, 24 Jan 1998 18:54:51 -0800 From a friend... > Today's question: What in the world is electricity and where does it > go after it leaves the toaster? > > Here is a simple experiment that will teach you an important electrical > lesson: On a cool dry day, scuff your feet along a carpet, then reach > your hand into a friend's mouth and touch one of his dental fillings. > Did you notice how your friend twitched violently and cried out in > pain? This teaches one that electricity can be a very powerful force, > but we must never use it to hurt others unless we need to learn an > important lesson about electricity. > > It also illustrates how an electrical circuit works. When you scuffed > your feet, you picked up batches of "electrons", which are very small > objects that carpet manufacturers weave into carpet so that they will > attract dirt. The electrons travel through your bloodstream and > collect in your finger, where they form a spark that leaps to your > friend's filling, then travel down to his feet and back into the > carpet, thus completing the circuit. > > AMAZING ELECTRONIC FACT: If you scuffed your feet long enough without > touching anything, you would build up so many electrons that your > finger would explode! But this is nothing to worry about unless you > have carpeting. > > Although we modern persons tend to take our electric lights, radios, > mixers, etc. for granted, hundreds of years ago people did not have any > of these things, which is just as well because there was no place to > plug them in. > > Then along came the first Electrical Pioneer, Benjamin Franklin, who > flew a kite in a lightning storm and received a serious electrical > shock. This proved that lightning was powered by the same force as > carpets, but it also damaged Franklin's brain so severely that he > started speaking only in incomprehensible maxims, such as, "A penny > saved is a penny earned." Eventually he had to be given a job running > the post office. > > After Franklin came other Electrical Pioneers whose names have become > part of our electrical terminology: Myron Volt, Mary Louise Amp, James > Watt, Bob Transformer, etc. These pioneers conducted many important > electrical experiments. Among them, Galvani discovered (this is the > truth) that when he attached two different kinds of metal to the leg of > a frog, an electrical current developed and the frog's leg kicked, even > though it was no longer attached to the frog, which was dead anyway. > Galvani's discovery led to enormous advances in the field of amphibian > medicine. Today, skilled veterinary surgeons can take a frog that has > been seriously injured or killed, implant pieces of metal in its > muscles, and watch it hop back into the pond. However, water is a > great conductor of electricity and the frog is immediately > electrocuted. > > But the greatest Electrical Pioneer of them all was Thomas Edison, who > was a brilliant inventor despite the fact that he lived in New Jersey. > Edison's first major invention in 1877 was the phonograph, which could > soon be found in thousands of American homes, where it basically sat > until 1923, when the record was invented. But Edison's greatest > achievement came in 1879 when he invented the electric company. > Edison's design was a brilliant adaptation of the simple electrical > circuit: the electric company sends electricity through a wire to a > customer, then immediately gets the electricity back through another > wire, then (this is the brilliant part) sends it right back to the > customer again. > > This means that an electric company can sell a customer the same batch > of electricity thousands of times a day and never get caught, since > very few customers take the time to examine their electricity closely. > In fact, the last year any new electricity was generated was 1937. > > Today, thanks to men like Edison and Franklin, and frogs like > Galvani's, we receive almost unlimited benefits from electricity. For > example, in the past decade scientists have developed the laser, an > electronic appliance so powerful that it can vaporize a bulldozer 2000 > yards away, yet so precise that doctors can use it to perform delicate > operations to the human eyeball, provided they remember to change the > power setting from "Bulldozer" to"Eyeball." - ----- End Included Message ----- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: Lehman drift Date: Sun, 25 Jan 1998 00:18:33 -0600 (CST) Barry; I do not know what parameters you set with the transfer function, but you may have a problem with the integrator : your original LP filter was also an integrator at 47 seconds. This is TI in the transfer function; what sort of Tn did you estimate? If the integrator capacitor has significant DC leakage, which varies with temperature, it will cause the mass position to wander around. (In addition to mechanical drift). You can measure the DC resistance of the capacitor(s), which MUST be non-polarized (or a pair of polarized (of twice the value) in series connected + to +) with a multimeter, it will take some time for the meter to charge a large capacitor. The DC R should be tens of megohms in both directions, or at least 10x the series resistor (you used 1 megohm). Are you using a non-polarized capacitor? Also for the differential feedback C. Also: the VBB output now contains the mass position component. To connect this to a recorder or digitizer (unless you have a 24-bit ADC), a long-period high-pass filter is needed, and usually an additional amplifier. I use 1000 uf, NP, into 1 megohm to an amplifier with a gain of 2 as a buffer to remove DC drift; it still passes periods of 10 minutes or more; you may want a shorter period corner with the horizontal. (see the curves of the step calibration on figure 10 of the figures page). With the unit here, the VBB output can range from + to - 7 volts (I have a +-9v regulated supply), which I monitor with a meter near the recorder so I know when the sensor needs to be recentered. It will also have a large drift anytime the covers have been removed for any length of time, and may take 4 to 6 hours to stabilize again. But the normal output from the high=pass buffer is microseims of 1 to 10 mv, and the RS digitizer range is only +-200mv. This near-DC response is because although the VBB output is flat to velocity from Tn up to the short period corner, it is flat to acceleration below Tn, so tilt, earth tides, acoustic gravity waves, etc, will be present in the output. You can modify the MCAD plot to show this by changing the plot axis to plot |Ai| rather than |Ai*Si|, or you can plot both. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: joke - electricity Date: Sun, 25 Jan 1998 21:01:30 +1200 At 06:54 PM 1/24/98 -0800, you wrote: >>From a friend... > >> Today's question: What in the world is electricity and where does it >> go after it leaves the toaster? >> yeah good one Larry, not too bad at all thanks Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: EMON Date: Sun, 25 Jan 1998 11:39:45 EST TO: TED BLANK, et.al : I am using the updated version of EMON (7). Without the F2 key being depressed it shows a fast sinsodial trace varying with the input possibly in "real-time". When the F2 key is pressed it shows a much slower trace. SETTINGS: A/D conv. per samp: 5 Display time compression: 10 Display Compression (verticle): 25 QUESTION: Is it possible to configure EMON to save quake data when the "Data Trace key (F2) is not initiated? If so how do I do it? THANKS Jim Allen Cerritos, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: EMON Date: Sat, 24 Jan 1998 22:19:58 -0800 Jim Change the number of samples taken per point to something higher like 60-70 and see how that changes the sample frequency(without F2 pressed) .. With 3 channels running I use 40 sample readings per point to get a sample frequency of 30 hz. I have a 386. Barry RADIOTEL wrote: > > TO: TED BLANK, et.al : I am using the updated version of EMON (7). Without > the F2 key being depressed it shows a fast sinsodial trace varying with the > input possibly in "real-time". When the F2 key is pressed it shows a much > slower trace. > SETTINGS: > A/D conv. per samp: 5 > Display time compression: 10 > Display Compression (verticle): 25 > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: vbb high-pass Date: Sun, 25 Jan 1998 11:57:56 -0600 (CST) Barry, I looked at the figure I posted of the electronics block diagram for the high-pass output configuration that is needed to remove DC drift and other ULP noise. It is conspicuously missing! oops and sorry about that. Which is why I appreciate feedback (no pun) from you and others trying to make VBB sensors. I will amend the drawing to show the large capacitor between the VBB output at the displacement detector and the buffer or "line driver" amplifier, which has a 1 megohm input resistor, which I should also show. Hopefully you will be acquiring data by now. BTW: if your recorder and/or ADC has a very high input impedance (like 1 meg), you can forgo the buffer amplifier,and just install the capacitance. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Mike Lozano Subject: Re:Seismo Hobby Special Date: Wed, 21 Jan 1998 12:24:08 -0600 To everyone on the PSN list, I am developing a five part television special for the Pulitzer Broadcasting station I work for. It's likely that this special will also be sent to the other Pulitzer stations in the group - like Chicken Man .... they're everywhere. I am looking for visual material to use in this special. Video tape (Broadcast Beta, if possible; or even VHS, High 8) of earthquake damage, drum-type recorder banks, seismologists out in the field, etc. Primarily, however, I'm looking for video (or even photos of the hobbyist and his/her equipment). The point behind this TV special is that even esoteric fields like seismology can be engaged in by 'regular' people; some of whom make significant contributions to the science. Larry Cochrane has been good enough to provide boards and software for this special, and I've constructed a large Lehman; a vertical using the probably now-forgotten dual cow magnets; and obtained a GeoSpace geophone. We're going to put the whole thing together in the next three weeks, so time is of the essence. My boss still thinks NO ONE does this as a hobby - I'm out to prove him wrong!!! In case you guys can talk (or have talked) the local television stations into shooting video of your setups, I sure would like to have a copy. I'd especially like to have video or photos of Dave's New Zealand operation, or the several Italian stations on the PSN. I'd be happy to provide VHS dubs of the special to those who provide a blank VHS tape. If you'd like to contact me personally for details: Mike Lozano, Senior Meteorologist KCCI Television 888 9th. St. Des Moines, Iowa 50309 (515)-247-8888 P.S. I'm around at the station from 10AM through 5:30PM. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: vbb high-pass Date: Sun, 25 Jan 1998 01:19:46 -0800 Sean Thomas Thanks for the info. I think my drifting is due to sensor tilting. I will install the highpass as you suggested. With the gain I have, 0.003" gives a 2 vt output. This is how I calibrated the sensor (0.003" feeler gauge). I have a small (5'x5') concrete pad currently. Would it be to Rube Goldberg to include another lowpass filter tied to a second coil to compensate for sensor tilt? It works for my Lehman but I didn't want it to fight with the speaker coil. I would set the cutoff frequency well below the VBB sensor response. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: supper bowl EVENT Date: Sun, 25 Jan 1998 13:33:41 -0700 Well...here in Denver, we are all getting fired up for the big game in the subburb of San Diego,....a county on the outer fringes of Colorado. The local psyche says Denver 27 and Grinbay 21. I do pay some attention to this one....she's 35 years old and a georgious blond. The Denver Broncos menu has been Jag-burgers, KC-burgers Pitts-burgers and now it is hopefully cheeseburgers; according to a highly estemmed local writer. Stuff you can eat with relish. Nevertheless...I still find pregame time for preparation...like putting on my bronco T-shirt, one of my own design...old, ragged, worn out, self imposed bronco logo with a felt tip pen. Uhhh....maybe alittle off center from the front, but nevertheless in the proper team spirit. I did manage to get the letters right side up, buth the local management did not seem to approve of the art masterpiece. No real art appreciation. Just a trip to the gas-food store this morning, reminded me of the importance of this event....blue & orange balloons...like colors in the trees on ribbons. Even the next door neighbor has a real nice Bronco logo promiently displayed on the fencing of their front porch. Why do they have to be right next door? Hhmmmm This has nothing normally to do with seismographs; but I figure that being as I don't have a horses foot to rub for good luck, I should at least come up with something that should swing it the way of the Broncos. So...event...swing...they are at least words all good seismophiles should be familiar with. If you catch the "drift" of all this; it implys something of a very special cosmic enhancing quality being placed upon the altar "mass". .....Nah....not the real thing....but a closely related secondary object.....like a TEKTITE! Yes indeed, nothing common here for the cause.....after all, it maybe a long time before there is another replay. Yes...I'am really not all that down to earth all the time. One has to rise up to the occasion. P.S.....don't tell D.N. in New Zealand about this....somehow ..............I still feel on probation....OK? Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: Re: EMON Date: Sun, 25 Jan 1998 16:59:28 EST TO: BARRY Thanks for your help re. EMON. TO: BARRY, SEAN-THOMAS, ET. AL. By the way you and Sean-Thomas and others were recently discussing increasing the period of a verticle boom with examples of the physics involved. One example used was a " T " boom configuration with, I believe mass on each end of the boom. Since I am not an engineer, just a Mental Health administrator, I am not sure I really understood all the basic equations. Do you (OR ANYONE ELSE VIEWING THIS) know of an actual seismometer configured in this fashion and if so how would it be "hinged". Quite frankly your discussion stimulated my interest in purchasing a very very light piece of 1 inch square tubing 5 feet in length that could be used as a boom. Jim Allen Cerritos, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roger Baker Subject: Re: EMON Date: Sun, 25 Jan 1998 20:16:01 -0600 >TO: BARRY, SEAN-THOMAS, ET. AL. >By the way you and Sean-Thomas and others were recently discussing increasing >the period of a verticle boom with examples of the physics involved. One >example used was a " T " boom configuration with, I believe mass on each end >of the boom. Since I am not an engineer, just a Mental Health administrator, >I am not sure I really understood all the basic equations. >Do you (OR ANYONE ELSE VIEWING THIS) know of an actual seismometer configured >in this fashion and if so how would it be "hinged". Quite frankly your >discussion stimulated my interest in purchasing a very very light piece of 1 >inch square tubing 5 feet in length that could be used as a boom. >Jim Allen >Cerritos, California Jim, et al, Let me take a stab at a critique of your suggestion to use a very long light boom as the basis for a vertical. I assume the reason why you propose a long boom is that if you were to put the mass far from the hinge, the natural period would be long, which is generally a good thing. But there are at least three practical reasons why a very long boom or horizontal beam could weaken this design advantage. The first is that air currents and thermal variations over the length of the instrument will probably become more significant, and these are troublesome. The second problem is that the hinge now gets very tiny in proportion to the length of the beam, making it difficult to control transverse modes of vibration--the boom should be rigid and only move tightly along one axis for good results. The hinge, what ever its nature, shouldn't be too narrow in proportion to beam length. The third problem is that a long boom will have a large total surface area and this will tend to increase the importance of air damping. Assuming that we are talking about a force feedback instrument, we want the total mechanical losses within the system to be as low as possible. We really want a high-Q system that oscillates forever, if possible, meaning that the system is capable of capturing and retaining the tiny amount of kinetic energy we are trying to detect -- until and unless we almost exactly neutralize this tiny amount kinetic energy with our force feedback force so that the boom is held very nearly stable. In other words a good force feedback instrument should ideally oscillate a long time with the feedback force turned off, indicating that such air friction and all other losses are inherently low before we add our own equal and opposite force to the system. So air damping losses are a significant design factor that typically cause us to use a few ounces of mass to help overcome such air friction losses. Once all this is achieved, we are set to use force feedback to artificially lengthen the natural period of the system. Of course in a Lehman the design philosophy is different. With this passive system we don't use any force feedback, but instead choose to have a very long natural period and then deliberately ADD just enough damping losses so the beam will not overshoot in its horizontal motion -- the Lehman beam is damped just enough so as to respond linearly to all frequencies higher than the long natural period of ten seconds or so needed to capture teleseismic events. At any rate this is my understanding of the various design trade-offs involved. Sean-Thomas or somebody else should chime in if I have part of the picture wrong. --Yours, Roger Baker At 04:59 PM 1/25/98 EST, you wrote: >TO: BARRY Thanks for your help re. EMON. > >TO: BARRY, SEAN-THOMAS, ET. AL. >By the way you and Sean-Thomas and others were recently discussing increasing >the period of a verticle boom with examples of the physics involved. One >example used was a " T " boom configuration with, I believe mass on each end >of the boom. Since I am not an engineer, just a Mental Health administrator, >I am not sure I really understood all the basic equations. >Do you (OR ANYONE ELSE VIEWING THIS) know of an actual seismometer configured >in this fashion and if so how would it be "hinged". Quite frankly your >discussion stimulated my interest in purchasing a very very light piece of 1 >inch square tubing 5 feet in length that could be used as a boom. >Jim Allen >Cerritos, California > >_____________________________________________________________________ > >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: RADIOTEL Subject: Re: EMON Date: Sun, 25 Jan 1998 22:10:21 EST TO: ROGER BAKER Thanks for the analysis and advice. The idea I had was just a vertical seismometer (with no force feed-back) to achieve about a 4 to 5 second period. I had envisioned the total boom length to be about 3 to 3.5 feet hinged at the center with mass on each end. However, I guess I had better re-think this approach. Again thanks for your help. Jim Allen Cerritos, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: EMON Date: Sun, 25 Jan 1998 10:09:56 -0800 Jim A configuration which I used was a beam with a hinge at one end and the mass at the other end. The boom was kept up by a long spring that was attached to the boom at the mass and about 6" above the hinge on a vertical post that was attached to the base. The closer you get to the hinge the longer the period but the larger the spring force. I put together several springs from the hardware store to get a long one. I'm not sure how much vibration one might get from the spring subject to vertical motion. I think Sean's spring configuration may be better but a little more complicated. Barry > Thanks for the analysis and advice. > The idea I had was just a vertical seismometer (with no force feed-back) to > achieve about a 4 to 5 second period. I had envisioned the total boom length > to be about 3 to 3.5 feet hinged at the center with mass on each end. > However, I guess I had better re-think this approach. > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ted Blank Subject: Re: supper bowl EVENT Date: Sun, 25 Jan 1998 22:30:35 -0800 (PST) Buy that psychic a cheeseburger! What a game! > > Well...here in Denver, we are all getting fired up > for the big game in the subburb of San Diego,....a county on > the outer fringes of Colorado. > > The local psyche says Denver 27 and Grinbay 21. I do pay > some attention to this one....she's 35 years old and a > georgious blond. > > The Denver Broncos menu has been Jag-burgers, KC-burgers > Pitts-burgers and now it is hopefully cheeseburgers; according > to a highly estemmed local writer. Stuff you can eat with relish. > > Nevertheless...I still find pregame time for preparation...like > putting on my bronco T-shirt, one of my own design...old, > ragged, worn out, self imposed bronco logo with a felt tip pen. > Uhhh....maybe alittle off center from the front, but nevertheless > in the proper team spirit. I did manage to get the letters right > side up, buth the local management did not seem to approve > of the art masterpiece. No real art appreciation. > > Just a trip to the gas-food store this morning, reminded me of > the importance of this event....blue & orange balloons...like > colors in the trees on ribbons. Even the next door neighbor > has a real nice Bronco logo promiently displayed on the > fencing of their front porch. Why do they have to be right > next door? Hhmmmm > > This has nothing normally to do with seismographs; but I figure > that being as I don't have a horses foot to rub for good luck, > I should at least come up with something that should swing it > the way of the Broncos. So...event...swing...they are at least > words all good seismophiles should be familiar with. If you > catch the "drift" of all this; it implys something of a very special > cosmic enhancing quality being placed upon the altar "mass". > ....Nah....not the real thing....but a closely related secondary > object.....like a TEKTITE! Yes indeed, nothing common > here for the cause.....after all, it maybe a long time before there > is another replay. Yes...I'am really not all that down to earth > all the time. One has to rise up to the occasion. > > P.S.....don't tell D.N. in New Zealand about this....somehow > .............I still feel on probation....OK? > > Meredith Lamb > > > > _____________________________________________________________________ > > 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: Ted Blank Subject: Re: EMON Date: Sun, 25 Jan 1998 22:44:04 -0800 (PST) Jim, The reason the data trace goes slower when you press F2 is that this turns on the display of the actual data, printed as a number, in the upper left hand corner of the screen. Since it takes many thousands of instructions to format and print the numbers, EMON cannot take as many samples per second. So the data trace slows down. When you press F2 again, the display of the numbers disappears. Now the entire power of the CPU is available for sampling again, so the data trace speeds up. However all this has nothing to do with the decision to save data to disk. That is made when enough wiggles are detected in a short enough time for EMON to consider it likely that something worth saving has been detected. You should adjust your sampling rate by changed the value of A/D conversions per sample. More conversions per sample will give you a slower sampling rate. You adjust your sensitivity by changing the values of PeakCountFilter, NoiseRangeToIgnore and SampleCountToSaveFile. Check the documentation for instructions in how to adjust these values. However, you can try this test. If you jump up and down near your sensor, you should be able to make the data trace go above and below the noise zone (the two small marks above and below the larger central mark on the EMON display screen). If you can't make the trace move even this much by jumping around, your amplification may be too low, your boom may be all the way against one of the stops, etc. What kind of amplifier/filter are you using? Feel free to give me a call if you need some real time assistance. Regards, Ted > > TO: TED BLANK, et.al : I am using the updated version of EMON (7). Without > the F2 key being depressed it shows a fast sinsodial trace varying with the > input possibly in "real-time". When the F2 key is pressed it shows a much > slower trace. > SETTINGS: > A/D conv. per samp: 5 > Display time compression: 10 > Display Compression (verticle): 25 > > QUESTION: Is it possible to configure EMON to save quake data when the "Data > Trace key (F2) is not initiated? If so how do I do it? > THANKS > Jim Allen > Cerritos, California > > _____________________________________________________________________ > > 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: Ted Blank Subject: Joke - woodworking and seismology Date: Sun, 25 Jan 1998 22:48:20 -0800 (PST) Cal State Northridge has a degree program in Woodworking. Sanding is easy- you just put the sandpaper on the wood and wait for an aftershock. Well I thought it was funny. And show me some other jokes that combine seismology with anything before you complain! :-) The Phantom _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: Re: EMON Date: Mon, 26 Jan 1998 02:09:50 EST TO: BARRY Thanks for sharing your experience with me. I'll keep it in mind when I finally decide on what approach to take. Again Thanks Jim Allen Cerritos, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: Re: EMON Date: Mon, 26 Jan 1998 02:23:24 EST TED BLANK I have EMON working great now. I have the A/D conv. per sample set on 40 and it really looks good. I have a vertical seismometer that I am still adjusting - its made simular to the one that Sean-Thomas developed (I copied his actually) but without the force feed-back. I have a bank of Gould dc amps and am using one with a 15 Hz filter (would use 10 Hz but the Gould only has a 5Hz and 15 Hz filter). I now get an enhanced trace when I walk across the room. It actually responds to my wife on our exercise machine which is upstairs (It records her as an earthquake). Your Program EMON is really great. Many thanks Jim Allen Cerritos, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: joe irvine Subject: Re: Joke - woodworking and seismology Date: Sun, 25 Jan 1998 23:27:52 -0800 At 10:48 PM 1/25/98 -0800, you wrote: > >Cal State Northridge has a degree program in Woodworking. Sanding is easy- you just put the sandpaper on the wood and wait for an aftershock. > > >Well I thought it was funny. And show me some other jokes that combine seismology with anything before you complain! :-) > >The Phantom >OK Late one night, a burglar broke into a house that he thought was empty. just as he entered there was a small earthquake and the house shook suddenly he froze in his tracks and he heard a loud voice say, "Jesus is watching you!" Silence returned to the house, so the burglar crept forward again. "Jesus is watching you," the voice boomed again. The burglar stopped dead again. He was frightened. Frantically, he looked all around. In a dark corner, he spotted a bird cage and in the cage was a parrot. He asked the parrot, "Was that you who said Jesus is watching me?" "Yes," said the parrot. The burglar breathed a sigh of relief, then he asked the parrot: "What's your name?" "Clarence," said the bird. "That's a dumb name for a parrot," sneered the burglar. "What idiot named you Clarence?" The parrot said, "The same idiot who named the Rottweiller Jesus." >_____________________________________________________________________ > >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: joe irvine Subject: Re: Joke - woodworking and seismology Date: Sun, 25 Jan 1998 23:32:56 -0800 At 10:48 PM 1/25/98 -0800, you wrote: > >Cal State Northridge has a degree program in Woodworking. Sanding is easy- you just put the sandpaper on the wood and wait for an aftershock. > > >Well I thought it was funny. And show me some other jokes that combine seismology with anything before you complain! :-) > >The Phantom >ok Late one night, a burglar broke into a house that he thought was empty. Just then a small earthquake shook the house.He froze in his tracks and then he heard a loud voice say, "Jesus is watching you!" Silence returned to the house, so the burglar crept forward again. "Jesus is watching you," the voice boomed again. The burglar stopped dead again. He was frightened. Frantically, he looked all around. In a dark corner, he spotted a bird cage and in the cage was a parrot. He asked the parrot, "Was that you who said Jesus is watching me?" "Yes," said the parrot. The burglar breathed a sigh of relief, then he asked the parrot: "What's your name?" "Clarence," said the bird. "That's a dumb name for a parrot," sneered the burglar. "What idiot named you Clarence?" The parrot said, "The same idiot who named the Rottweiller Jesus." >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: seismo triangulation using PC Date: Mon, 26 Jan 1998 15:14:00 +0000 S-T Morrissey wrote: > Seismic wave velocities are of the order of 2 to 6 km /second, > depending on the wave type. So even a slow surface wave at > 2000 m/sec would zip across your 200 m array in 0.1 second. > Small arrays have been used for azimuthal data, but they are > usually at least a kilometer on a side, or 10 km for p-waves. > There used to be an array operated by SLU to track hurricanes, > since they produce large 3 to 6 second microseisms. But the > azimuth was determined by phase coherence across the array to > get a direction to the source. Several such arrays could locate > hurricanes as they approached the coast. > Hi Sean, I have a 250ft x 100ft field and for some time now I have considered the possibility of putting 3 seismos in a triangle pattern 100ft apart. Given the speeds above, the modern PC runs at 60 meg CPU clock speed at least. I estimate that not more than 50 clock cycles would be required to input data from each of three Seismos, and store into PC memory, in their exact order of arrival, so about 150 clock cycles total. During this PC time period, (approx 2 micro secs), the waves have only travelled 1/4 inch !! (Aren't they SLOW .) So effectively, in terms of wave speeds, the PC would be sensing all 3 seismos at the SAME INSTANT. The PC would have to compare arrival times, and the ORDER in which they arrived, and triangulate this info for direction, but all this CPU downtime could be done latter, after the quake had ceased. I appreciate that all seismos would have to be identical, in order that PC could identify same points on all 3 seismo inputs, (such as max peaks or same rise times etc), in order to calculate the timing and triangulation required. At 100ft. spacing, max. wave delays to any 2 seismographs would be ~5 milli secs....quite a long period in terms of PC inputs at 2 micro secs.per sweep. I wonder if any work has been done along these lines......if one used a very fast Pentium CPU, the 3 seismos could be contained within a medium sized garden, as inputting time to PC would be 4-5 times faster, so a 50ft array may be large enough. Do you think that this all is a possibility, as I don't wish to destroy THREE stereo speakers needlessly . Regards, Albert Noble (England). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: large sw New Zealand event Date: Tue, 27 Jan 1998 12:49:01 +1200 hi all, large ~M6 event 400 km from me will post soon several aftershocks as well 26/ 01/ 98 2306:56 UTC P arrival Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: seismo triangulation using PC Date: Mon, 26 Jan 1998 19:07:04 -0600 (CST) Albert, The trouble with seismic waves is a phenomenon called dispersion, which means that the farther they travel, the longer the apparent wavelength is. Another is that earthquake rupture velocities are relatively slow, so even if you have a quake in your basement, you would be lucky to see waveforms shorter than 0.01 second, and if it was a km away, they would have dispersed to 0.03 second, and by 10km, to 0.1 second. So determining the time difference between such arrivals, even by phase matching, requires a large relative distance between seismic stations. Like the 0.1 second wave (10hz), can be resolved to about 0.01 second with a 200 sps digitizer (nyquist = 100hz), and traveling at 5km/second, would travel 50 meters in that time. Any waves coming from farther away, like the next county, will be closer to 0.3hz, requiring a larger array. So most such arrays are kilometers on a side. Actually, a tripartite array can only point in one direction towards the source, and S-P times can give the approximate distance. The programs that are used to locate earthquake hypocenters actually use a recursive trial-and-error approach. Roughly speaking, they start out with the assumption that the quake occurred at the first station to detect it, and then, using available earth models and velocity profiles, they calculate when the wave should arrive at other stations. It then compares its' calculations with the actual arrivals, and moves its "trial" epicenter (both laterally and in depth) away from the station that recorded an earlier arrival than calculated, and vv., and then recalculates the hypocenter. It has a solution only after minimizing the differences between its' arrivals and the actual arrivals. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: seismo triangulation using PC Date: Mon, 26 Jan 1998 19:07:04 -0600 (CST) Albert, The trouble with seismic waves is a phenomenon called dispersion, which means that the farther they travel, the longer the apparent wavelength is. Another is that earthquake rupture velocities are relatively slow, so even if you have a quake in your basement, you would be lucky to see waveforms shorter than 0.01 second, and if it was a km away, they would have dispersed to 0.03 second, and by 10km, to 0.1 second. So determining the time difference between such arrivals, even by phase matching, requires a large relative distance between seismic stations. Like the 0.1 second wave (10hz), can be resolved to about 0.01 second with a 200 sps digitizer (nyquist = 100hz), and traveling at 5km/second, would travel 50 meters in that time. Any waves coming from farther away, like the next county, will be closer to 0.3hz, requiring a larger array. So most such arrays are kilometers on a side. Actually, a tripartite array can only point in one direction towards the source, and S-P times can give the approximate distance. The programs that are used to locate earthquake hypocenters actually use a recursive trial-and-error approach. Roughly speaking, they start out with the assumption that the quake occurred at the first station to detect it, and then, using available earth models and velocity profiles, they calculate when the wave should arrive at other stations. It then compares its' calculations with the actual arrivals, and moves its "trial" epicenter (both laterally and in depth) away from the station that recorded an earlier arrival than calculated, and vv., and then recalculates the hypocenter. It has a solution only after minimizing the differences between its' arrivals and the actual arrivals. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Caruso Subject: Re: seismo triangulation using PC Date: Mon, 26 Jan 1998 20:47:57 -0500 (EST) At work we have 4 ceilometers hooked up to a pentium 133mhz and it gets kinda touchy w/all the data coming in at the same time. It only has 16meg of ram but it chugs right along. It has an operating program that logs at the same time but the amount of processor usage depends on the complexity of the program calculations, ours being an equivalent graphic type to EMON... On Mon, 26 Jan 1998, prewar wrote: > S-T Morrissey wrote: > > > Seismic wave velocities are of the order of 2 to 6 km /second, > > depending on the wave type. So even a slow surface wave at > > 2000 m/sec would zip across your 200 m array in 0.1 second. > > Small arrays have been used for azimuthal data, but they are > > usually at least a kilometer on a side, or 10 km for p-waves. > > There used to be an array operated by SLU to track hurricanes, > > since they produce large 3 to 6 second microseisms. But the > > azimuth was determined by phase coherence across the array to > > get a direction to the source. Several such arrays could locate > > hurricanes as they approached the coast. > > > > Hi Sean, > I have a 250ft x 100ft field and for some time now I have > considered the possibility of putting 3 seismos in a triangle > pattern 100ft apart. Given the speeds above, the modern > PC runs at 60 meg CPU clock speed at least. I estimate that > not more than 50 clock cycles would be required to input data > from each of three Seismos, and store into PC memory, in their > exact order of arrival, so about 150 clock cycles total. > > During this PC time period, (approx 2 micro secs), the waves > have only travelled 1/4 inch !! (Aren't they SLOW .) > So effectively, in terms of wave speeds, the PC would be sensing > all 3 seismos at the SAME INSTANT. > The PC would have to compare arrival times, and the ORDER > in which they arrived, and triangulate this info for direction, > but all this CPU downtime could be done latter, after the quake > had ceased. I appreciate that all seismos would have to be > identical, in order that PC could identify same points on all > 3 seismo inputs, (such as max peaks or same rise times etc), > in order to calculate the timing and triangulation required. > > At 100ft. spacing, max. wave delays to any 2 seismographs would > be ~5 milli secs....quite a long period in terms of PC inputs > at 2 micro secs.per sweep. > > I wonder if any work has been done along these lines......if one > used a very fast Pentium CPU, the 3 seismos could be contained > within a medium sized garden, as inputting time to PC would be > 4-5 times faster, so a 50ft array may be large enough. > > Do you think that this all is a possibility, as I don't wish to > destroy THREE stereo speakers needlessly . > > Regards, > > Albert Noble (England). > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L STEPHEN CARUSO CET KB8UGH "Coincidence is a shortsighted mental delusion" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Caruso Subject: Re: seismo triangulation using PC Date: Mon, 26 Jan 1998 20:47:57 -0500 (EST) At work we have 4 ceilometers hooked up to a pentium 133mhz and it gets kinda touchy w/all the data coming in at the same time. It only has 16meg of ram but it chugs right along. It has an operating program that logs at the same time but the amount of processor usage depends on the complexity of the program calculations, ours being an equivalent graphic type to EMON... On Mon, 26 Jan 1998, prewar wrote: > S-T Morrissey wrote: > > > Seismic wave velocities are of the order of 2 to 6 km /second, > > depending on the wave type. So even a slow surface wave at > > 2000 m/sec would zip across your 200 m array in 0.1 second. > > Small arrays have been used for azimuthal data, but they are > > usually at least a kilometer on a side, or 10 km for p-waves. > > There used to be an array operated by SLU to track hurricanes, > > since they produce large 3 to 6 second microseisms. But the > > azimuth was determined by phase coherence across the array to > > get a direction to the source. Several such arrays could locate > > hurricanes as they approached the coast. > > > > Hi Sean, > I have a 250ft x 100ft field and for some time now I have > considered the possibility of putting 3 seismos in a triangle > pattern 100ft apart. Given the speeds above, the modern > PC runs at 60 meg CPU clock speed at least. I estimate that > not more than 50 clock cycles would be required to input data > from each of three Seismos, and store into PC memory, in their > exact order of arrival, so about 150 clock cycles total. > > During this PC time period, (approx 2 micro secs), the waves > have only travelled 1/4 inch !! (Aren't they SLOW .) > So effectively, in terms of wave speeds, the PC would be sensing > all 3 seismos at the SAME INSTANT. > The PC would have to compare arrival times, and the ORDER > in which they arrived, and triangulate this info for direction, > but all this CPU downtime could be done latter, after the quake > had ceased. I appreciate that all seismos would have to be > identical, in order that PC could identify same points on all > 3 seismo inputs, (such as max peaks or same rise times etc), > in order to calculate the timing and triangulation required. > > At 100ft. spacing, max. wave delays to any 2 seismographs would > be ~5 milli secs....quite a long period in terms of PC inputs > at 2 micro secs.per sweep. > > I wonder if any work has been done along these lines......if one > used a very fast Pentium CPU, the 3 seismos could be contained > within a medium sized garden, as inputting time to PC would be > 4-5 times faster, so a 50ft array may be large enough. > > Do you think that this all is a possibility, as I don't wish to > destroy THREE stereo speakers needlessly . > > Regards, > > Albert Noble (England). > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L STEPHEN CARUSO CET KB8UGH "Coincidence is a shortsighted mental delusion" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Sunspot activity increased Date: Mon, 26 Jan 1998 20:29:57 -0700 BTW: All you that follow sunspots will be surprised to see a recent upsurge in activity. Triple digits on 980125!! http://dxlc.com/solar/index.html -- ---/---- Charles P. Watson Seismo-Watch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Mouser 42TL021 Disassembly Date: Mon, 26 Jan 1998 22:21:12 -0700 Sean, Would be interested in your disassembly method of the 2 transformers TL021 & TM009, to make the total vrdt? Any tips to safeguard the coils from heat, or hand safety precautions? Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: the main event data Date: Tue, 27 Jan 1998 18:39:09 +1200 hi ppl here is the data for the main NZ event if any of u are wanting to fill in the blanks of my posted event file 980126B1.DNN it was supplied by the New Zealand Seismological Observatory in Wellington city. U.T.C.: 1998 January 26 23:05:54.4 NZST: 1998 January 27 11:05:54.4 am Lat, Long: 47.92S 164.94E Location: 233 km SSW of Puysegur Point (off the sw tip of the Sth Is.) Focal depth: 33 km Magnitude: ML 5.6 No felt information to hand Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: ADMIN: Double postings and List Rules Date: Mon, 26 Jan 1998 23:00:05 -0800 Hi, I, and others, have noticed that some messages are being double posted. Some people are using PSN-L@............. AND PSN-L@.............. in there messages. Please, only use one address. Either should work but some people, and I don't know why, are having problems with the psn.quake.net domain name. If you are having problems with one email address please try the other, but not both. Also, please don't send simple "thank you" type messages to the list. They should be sent to the sender directly. We all, including myself , need to remember that when you hit the reply button you are replying to the list, not the sender of the message. I just received a updated list of rules for another mailing list (a list on wildlife rehabitation, besides recording EQ's I enjoy rehabing local wildlife) I am on. I changed it to meet our needs, and I will posting it now and then. I will also add it to the welcome message sent to new members. 1) Keep all posts as short as possible and to the point. (I only have a certain amount of bandwidth to send out email messages) 2) If you are including words from someone else's post (that you are referring or responding to), do NOT include more than a line or two of that post... we have already seen what they wrote. When replying, please edit out the following message appended to each outgoing PSN-L message: __________________________________________________ Public Seismic Network Mailing List (PSN-L) 3) Do not send personal messages through the list. - post to the list if you think your information would be beneficial for everyone to read (this is how we all can learn) - post directly to the individual if it is a personal note, an "I agree with what you said" or "Thank you" type notes. 4) Do not send "me too's", "I agree's" or such to the list (it just wastes my bandwidth and other peoples time). 5) Do NOT send computer virus warnings (such as the "good times" virus) to the list; these are spams and not true (again, don't waste our time "warning" us of these) 6) Send only TEXT messages to the list. Do not include any attachments, HTML tags (this is referring to HTML code not links), or so forth. If you have a picture, or other binary type files to share with the group, you can uploaded when using FTP to ftp://psn.quake.net/incoming. 7) ALWAYS treat everyone here with respect and post with professionalism. Any abusive, sarcastic, or berating behavior on the list will be cause for list suspension and will not be tolerated. Please report any occurrences of this to the listowner (cochrane@................ If anyone has anything they would like to add to the list rules please let me know. Thanks. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: F/U McMaster-Carr Phosphor Bronze Stock Date: Tue, 27 Jan 1998 11:37:02 -0700 No clean, flat, unmarred phosphor bronze sources in Denver including machine shop supply places. McMaster-Carr on net does carry cheaper & smaller roll of phosphor bronze. $10.95, for .005" thick, 6" inch wide X 50", plus shipping (use email-?). Stock # 9020K41 on page 903. Adjacent to same, is listing of blue tempered spring steel rolls in various thicknesses as per phosphor bronze. Search under metal shim stock, use page backup or forward on site for page 903. They do have email & have answered my 2 inquirys...weekday..rapid. Suggest u ck out and consider if metal source not local for whatever seismo you maybe considering making or for experimental use. New source too me. Not bad for quanity on prices. Ck or crd card ok. Web site somewhat still under construction, ck out all & be patient. Hope that this post is of interest to some. Tnks, M. Lamb ...Denver, Co. U.S.A. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: seismo triangulation using PC Date: Tue, 27 Jan 1998 18:44:33 +0000 Hi Sean, I had thoughts of plotting trace from one seismo, then with suitable software, being able to match exactly the second seismo trace to first, then match third to these two, (by manually shifting traces back and forth on VDU). When ALL 3 were coincident on VDU, then PC would 'know' both TIME and the ORDER in which 3 recieved signals arrived, and hence know their direction, even given that the waveforms were long as you described. ( PC memory position of coincident signals would give this info). Regards, Albert Noble (England). S-T Morrissey wrote: .............................. you would be lucky to see waveforms shorter than 0.01 second, > and if it was a km away, they would have dispersed to 0.03 second, > and by 10km, to 0.1 second. So determining the time difference > between such arrivals, even by phase matching, requires a large > relative distance between seismic stations. > .........................snip........................ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Warren Shedrick" Subject: Geophone amplifier Date: Tue, 27 Jan 1998 11:03:45 +0000 I have recently recieved two geophones from Mr Juels, A 4.5Hz horizontal L-28 and a 4.5Hz vertical L-15 (Mark Products). I will be using these for local earthquake monitoring in the Oregon/Washington USA area. Could anyone recommend what type of amplifier/filter would be suitable to use with these geophones. I am using a Dataq two channel data acquisition module, a DMM with data logging capabilities(RS232) similiar to the Radio Shack Thank you Warren Shedrick _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: Mouser 42TL021 Disassembly Date: Tue, 27 Jan 1998 18:40:43 -0600 (CST) Meredith, It doesn't take much heat to soften the wax that holds the transformers together. First peel off the frame and the tape, then hold a pencil solder iron against one side of the core until the wax on the other side melts, which takes about 30 seconds. THen you can slip out a few of the laminates with a small screwdriver, and all of them come out. It really doesn't get too hot to handle. You don't want to melt the plastic coil form. And don't bend the laminates. I separate all the "I" laminates from the "E" laminates, and clean the remaining wax off with a solvent. The epoxy doesn.t stick to the wax very well. Then the E shapes are pushed back into the coil FROM the side with the leads. I found that I can replace more than came out, like 19 laminates. So I usually take apart three transformers. The plastic coil former now at the open face of the inductor may protrude above the core, so I carefully use a razor knife to pare it down to size without cutting into the coils. This is where I usually ruin the coil by cutting too close. Check the coils with an ohmmeter. The open face should be free of any raggedness that might touch the vane in the VRDT configuration. regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Geomagnetic Field Strength Changes Date: Tue, 27 Jan 1998 17:58:18 -0800 (PST) Hello All: I distinctly measured a variation in the level of the field over the past 24 hours at approximately 3 Hz. It was nearly constant during the previous two weeks of observations. Last time I noticed a change was on the day of the M4.3 located near Chino, CA measured -167 dBv (Though not as severe of a change as then). So, I'm waiting to see if there is anything to this level change. If it gets any larger in amplitude than say -170 dBv, I will post another report. Those of you with seismometers get ready for something soon. If nothing comes of this, then it was probably caused by an increase in Solar activity! (disclaimer) Frank Condon "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" mail to:frankcnd@.......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: kathy mortensen Subject: volcano Date: Wed, 28 Jan 1998 10:39:10 -0700 A web site has been set up to inform the community of seismic activity relating to the volcano off the coast of Oregon & Washington. http://newport.pmel.noaa.gov/axial98.html I recorded 3 distant events yesterday: KOMANDORSKY ISL. 5.7Mb 3499 mi. 19:17:00 UTC S. FIJI ISL. 5.4Mb 5744 mi. 20:06:29 UTC S. FIJI ISL. 5.5Mb 5739 mi. 21:17:15 UTC I notice that on the "BIG" stations the waveforms are 20 to 30 minutes or more long, mine are only 20 to 30 sec. long ---- come on STM-8. Oh well, I'm having a great time. Look for my present station info. on the list, I sent it yesterday!!! SKM (Stephen) lat. 38.828N / long. 120.978W _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Bob Fryer Subject: Axial Volcano re: NW offshore quakes Date: Wed, 28 Jan 1998 14:58:20 -0800 Hello PSNers, THIS MESSAGE IS POSTED ON THE RIDGE EVENT DETECTION AND RESPONSE WEBSITE AT: http://ridge.unh.edu/edr/ _______________________________________________________________ Beginning at 1200 GMT on 25 January 1998, intense seismicity was detected in the northeast Pacific Ocean using the T-phase Monitoring System developed by NOAA/PMEL to access the U.S. Navy's SOund SUrveillance System (SOSUS). This episode appears to be the most intense yet observed by PMEL's monitoring effort. The initial activity was located on the summit and southern flank of Axial Seamount on the central Juan de Fuca Ridge near 45 55'N and 130 00'W, approximately 300 miles west of Cannon Beach, Oregon. A possible response effort is being organized by NSF/RIDGE and NOAA/VENTS investigators. A website has been established by PMEL to keep the community informed of seismic activity and response efforts at: http://newport.pmel.noaa.gov/axial98.html This page will be updated daily while the activity continues. -Chris Fox and Bob Dziak, NOAA/PMEL, Newport, Oregon ________________________________________________________________ RIDGE Office Phone: (603) 862 - 4051 Ocean Process Analysis Laboratory FAX: (603) 862 - 0083 Morse Hall Email: ridge@....... 39 College Road WWW: http://ridge.unh.edu University of New Hampshire Durham, New Hampshire 03824-3525 Bob Fryer -- on the Cascadia Subduction Zone ----- earthquake WARNING research ----- --- animals, people, scientific evidence --- --- http://www.teleport.com/~bfryer --- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Tinkler Subject: Pressure Transducer (Barometer) Electronic Date: Thu, 29 Jan 1998 01:59:19 EST I have been reading with great interest the many comments that have been posted here, and I'm looking forward to many more. I do have a need for some info that you'all may have stuck away some where. Do any of you have info on or know where I can get the infomation on building a transducer that could be wired up electronically to measure Barometric pressure? Respectfully Dave Carlson Tinkler@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Peter Subject: First Quake? Date: Thu, 29 Jan 1998 00:05:46 -0800 Dear PSN, I have following the PSN for some time and have finally set up my own seismograph in the garage. I think I recorded the 5.3 event on 98/01/28 at 23:29:43 near the Mariana Islands. The event arrived at my location at 23:53:00, about 24 minutes later. I am in San Jose, CA Is that about the correct time of arrival? Thanks, Pete Fleming alarm@........... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Seisguy Subject: Re: Volcano Erupts off Oregon Coast Date: Thu, 29 Jan 1998 09:44:15 EST Here's the AP story for those of you interested. Mike O'Bleness Northridge, CA > > Volcano Erupts off Oregon Coast > > .c The Associated Press > > By GEORGE TIBBITS > > SEATTLE (AP) - A massive underwater volcano has been erupting off the Oregon > coast for days, and scientists are scrambling to get closer to study how life > survives deep in the ocean. > > The eruptions at Axial Seamount are no danger to the public, said Chris Fox, > a National Oceanographic and Atmospheric Administration geologist who has > tracked thousands of regional earthquakes since the volcano awoke Saturday > night. > > Axial rises 4,500 feet off the ocean floor about 300 miles west of Cannon > Beach, Ore. Its peak is nearly 4,000 feet below the ocean surface. > > The eruption could shed light on subjects as diverse as the origin of life, > genetic compounds and whether life might be possible on Jupiter's moons, > researchers said Wednesday. > > Research into seismology, geology, chemistry and the strange organisms that > live on and beneath the mountain and the mysterious undersea Juan de Fuca > Ridge ``will keep us busy for years,'' Fox said. > > The ridge runs north and south for 400 miles, part of a zigzagging breach in > the ocean floor where two of the plates that form the Earth's crust are > spreading apart. Since initial mapping in the 1970s and 80s, scientists have > found numerous signs of seismic activity, including other eruptions. > > Studying the ridge has helped reveal how the crust is formed. It also has > led to the discovery of strange organisms, including clams, worms and crabs, > that thrive in high temperatures and pressures and are part of a food chain > based on bacteria in volcanic vents. > > A 1993 eruption disclosed the presence of an entire ecosystem of bacteria > and viruses in the volcanic rock of the sea floor, where they live on > hydrogen sulfide gas associated with volcanic activity. > > When there is a hydrothermal event, they reproduce very rapidly and are > blasted upward throughout the water column - one reason scientists want to > get to the volcano as soon as possible, Fox said. > > Some scientists think that the underwater vents might be the source of life > on the planet, and that the bacteria could contain genes millions of years > old. > > Studying those organisms not only might illuminate how life arose on Earth, > but could describe scenarios where life might exist in hostile environments > elsewhere in the solar system, including Jupiter's moons, Fox said. > > On a more practical level, he said, the bacteria's genetic material is of > great interest to biomedical and other research companies who hope it can be > used to produce new products. > > ``When an eruption goes off in the deep ocean, it's an environment that's so > strange to us in many regards, it immediately conjures up discovery,'' said > Steve Hammond, director of NOAA's ocean vents program. > > No one has seen the eruption. But Fox and other researchers say it's likely > that rivers of red-hot lava are flowing out of the volcano, along with giant > plumes of scalding, mineral-rich water carrying microbes that thrive beneath > the ocean floor. > > The eruption could last weeks or longer. > > Fox said the Oregon State University research ship Wecoma will probably be > sent to the sea above the mountain in early February in an expedition > sponsored by NOAA and the National Science Foundation. > > Unlike Mount St. Helens, which devastated hundreds of square miles with its > 1980 explosion, Axial is more likely oozing lava similar to volcanoes on > Hawaii. Hammond said the undersea mountains along the ridge in some ways > resemble the Hawaiian Islands, which are volcanoes that grew from the ocean > floor to eventually break the surface. > > On Monday, a conference opened at NOAA's regional center here to discuss > summer explorations at Axial, including the creation of the New Millennium > Observator, a permanent underwater network of sensors at the site. > > AP-NY-01-29-98 0130EST > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Rex Klopfenstein Jr" Subject: Re: Pressure Transducer (Barometer) Electronic Date: Thu, 29 Jan 1998 12:32:16 -0500 If am not mistaken, can't one use an absolute pressure transducer (differential pressure transducer with one port referenced to vacuum)? Several manufacture (look in Allied or Newark catalog) make absolute transducers. Motorola manufactures a number of transducer and also has quite a few tech bulletins. One will need some additional circuitry (of software) to compensate for altitude. I think all three of these distributors/manufactures have home pages. Rex Klopfenstein, Jr Bowling Green, OH ---------- > Do any of you have info on or know where I can get the infomation on building > a transducer that could be wired up electronically to measure Barometric > pressure? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Mike Lozano Subject: Re: Barometer Date: Thu, 22 Jan 1998 14:07:38 -0600 The Motorola MPX4115A makes a very good barometer. It's not only referenced to its own micro-vacuum chamber, but it's also conditioned to provide a 0-5 volt output. I've used this transducer in several designs and have been very pleased with its performance. Several companies such as FoxBoro make very good transducers, but you've got to add your own conditioning circuitry. In another vein, a differential transducer referenced to a 'leaky' vacuum chamber makes a very good microbarograph for the study of short period pressure changes. The 'leak' is calibrated so that weather systems (which are of relatively long period) are ignored, and short period excursions caused by meteor impacts, eruptions, landslides, etc., are shown. There's an excellent treatise on this under the electronic magazine 'The Electronic Bell Jar' on the Web. Mikel Lozano -0- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Volcano Erupts off Oregon Coast Date: Thu, 29 Jan 1998 10:29:23 -0700 I find it interesting that the news article jumped on the "massive submarine volcanic eruption" story with only seismic data to justify its origin. Yes, it is suggestive, but not conclusive. There have been many seismic swarms recorded around volcanos before without even the hint of an eruption - more recently, the Long Valley caldera at Mammoth Lakes. No doubt, an excursion similar to that of the Northern Gorda Ridge event would provide more conclusive evidence, the sooner the better. "Rivers of molten magma" -- indeed! -- ---/---- Charles P. Watson, Consulting Geologist Advanced Geologic Exploration Seismo-Watch / Earthquake Information Services Voice: 702-852-0992 / Fax: 702-852-3226 Office Location: 39.43N 119.71W mailto:watson@................ http://www.seismo-watch.com > > > > > Volcano Erupts off Oregon Coast > > > > .c The Associated Press > > > > By GEORGE TIBBITS > > > > SEATTLE (AP) - A massive underwater volcano has been erupting off the > Oregon > > coast for days, and scientists are scrambling to get closer to study how > life > > survives deep in the ocean. > > > > The eruptions at Axial Seamount are no danger to the public, said Chris > Fox, > > a National Oceanographic and Atmospheric Administration geologist who has > > tracked thousands of regional earthquakes since the volcano awoke Saturday > > night. > > > > Axial rises 4,500 feet off the ocean floor about 300 miles west of Cannon > > Beach, Ore. Its peak is nearly 4,000 feet below the ocean surface. > > > > The eruption could shed light on subjects as diverse as the origin of life, > > genetic compounds and whether life might be possible on Jupiter's moons, > > researchers said Wednesday. > > > > Research into seismology, geology, chemistry and the strange organisms that > > live on and beneath the mountain and the mysterious undersea Juan de Fuca > > Ridge ``will keep us busy for years,'' Fox said. > > > > The ridge runs north and south for 400 miles, part of a zigzagging breach > in > > the ocean floor where two of the plates that form the Earth's crust are > > spreading apart. Since initial mapping in the 1970s and 80s, scientists have > > found numerous signs of seismic activity, including other eruptions. > > > > Studying the ridge has helped reveal how the crust is formed. It also has > > led to the discovery of strange organisms, including clams, worms and crabs, > > that thrive in high temperatures and pressures and are part of a food chain > > based on bacteria in volcanic vents. > > > > A 1993 eruption disclosed the presence of an entire ecosystem of bacteria > > and viruses in the volcanic rock of the sea floor, where they live on > > hydrogen sulfide gas associated with volcanic activity. > > > > When there is a hydrothermal event, they reproduce very rapidly and are > > blasted upward throughout the water column - one reason scientists want to > > get to the volcano as soon as possible, Fox said. > > > > Some scientists think that the underwater vents might be the source of life > > on the planet, and that the bacteria could contain genes millions of years > > old. > > > > Studying those organisms not only might illuminate how life arose on Earth, > > but could describe scenarios where life might exist in hostile environments > > elsewhere in the solar system, including Jupiter's moons, Fox said. > > > > On a more practical level, he said, the bacteria's genetic material is of > > great interest to biomedical and other research companies who hope it can be > > used to produce new products. > > > > ``When an eruption goes off in the deep ocean, it's an environment that's > so > > strange to us in many regards, it immediately conjures up discovery,'' said > > Steve Hammond, director of NOAA's ocean vents program. > > > > No one has seen the eruption. But Fox and other researchers say it's likely > > that rivers of red-hot lava are flowing out of the volcano, along with giant > > plumes of scalding, mineral-rich water carrying microbes that thrive beneath > > the ocean floor. > > > > The eruption could last weeks or longer. > > > > Fox said the Oregon State University research ship Wecoma will probably be > > sent to the sea above the mountain in early February in an expedition > > sponsored by NOAA and the National Science Foundation. > > > > Unlike Mount St. Helens, which devastated hundreds of square miles with its > > 1980 explosion, Axial is more likely oozing lava similar to volcanoes on > > Hawaii. Hammond said the undersea mountains along the ridge in some ways > > resemble the Hawaiian Islands, which are volcanoes that grew from the ocean > > floor to eventually break the surface. > > > > On Monday, a conference opened at NOAA's regional center here to discuss > > summer explorations at Axial, including the creation of the New Millennium > > Observator, a permanent underwater network of sensors at the site. > > > > AP-NY-01-29-98 0130EST > > > > > > _____________________________________________________________________ > > 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: kathy mortensen Subject: Re: First Quake? Date: Thu, 29 Jan 1998 12:14:57 -0700 Peter wrote: > > Dear PSN, > > I have following the PSN for some time and have finally set up my own > seismograph in the garage. > > I think I recorded the 5.3 event on 98/01/28 at 23:29:43 near the > Mariana Islands. > The event arrived at my location at 23:53:00, about 24 minutes later. > I am in San Jose, CA Is that about the correct time of arrival? > > Thanks, > Pete Fleming > alarm@........... I used the QBASIC program found on the PSN to estimate the time of arrival to my station, which is about 30 miles more, and it estimated the arrival time of 23 hr 42.4 min. which puts it at about 13 min. I'm looking forward to other posts to see if I'm in the ball park??? I estimated your location at approx. 37.25N 121.8W SKM (Stephen) P.S. The QBASIC program has a bug in the BEARING calculation (unless it has been updated recently -- I emailed the programer -- if not I have a fairly simple fix!! _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Breckenridge, Colorado Meteor (?) Date: Thu, 29 Jan 1998 13:53:26 -0700 Well...I suffered thru 2 WHOLE days to write this new story up. Yes, Colorado has another possible meteorite added to the mass of the Rocky Mountains. I was waiting for retractions, or additions or confirmations....nothing in 2 days. According to the Denver Post newspaper it was a "daytime fireball" which hit south of Breckenridge Colorado near (?) a place called Good Pasture Tarn. Only observed by afew on 1/27/98 near the area. According to the Blue River Marshal Steve Ford, it (quote)" was a fairly large object that was on fire with smoke that was trailing off the back of it ". In the same article it said that the NASA's Goddard Space flight Center in Maryland has received a higher than normal number of meteor sightings this year. The above is a true proffesional report. Honest. This really happened....again! If you're interested in how I'am adjusting to this....it is real hard to restrain myself from further juicy comments. But.... I'am really trying! Oh..... how the temptation is there. Somehow .....I treasure my tektite more....lately. M. Lamb Denver, Colo. U.S.A. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Mike Stickney Subject: Re: First Quake? Date: Thu, 29 Jan 98 16:03:56 MST Peter and Stephen: In case you are not aware of it, John Lahr has a wonderful web site with an arrival time calculator at url: http://www.giseis.alaska.edu/Input/lahr/artim.html Simply plug in your station coordinates, indicate the maximum distance (180 degrees for world wide events) and minimum magnitude in which you are interested and submit. It returns arrival times of specified phases, distances and azimuths. I use it daily to identfy teleseisms and phases recorded by the Montana seismograph network. -Mike Stickney Montana Bureau of Mines and Geology ==================== >Peter wrote: >> I am in San Jose, CA Is that about the correct time of arrival? >I used the QBASIC program found on the PSN to estimate the time of >arrival to my station, which is about 30 miles more, and it estimated >the arrival time of 23 hr 42.4 min. which puts it at about 13 min. >I'm looking forward to other posts to see if I'm in the ball park??? >I estimated your location at approx. 37.25N 121.8W > SKM (Stephen) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Doug Crice Subject: Re: Geophone amplifier Date: Thu, 29 Jan 1998 11:36:22 -0800 Geophone amplifiers should be what are normally called "instrumentation" amplifiers with a floating differential input. That means that there are two inputs and the amplifier rejects signals which appear on both wires (like AC hum, for example). If you go to the analog devices or burr brown web pages, I would expect to see application notes and data sheets. The gain should be selected so that the maximum signal you expect with not saturate the amplifier (which means that the differential input times the gain doesn't reach the supply voltage. If the gain is too low, you would see the small stuff, and if it's too high, big local earthquakes will saturate the system. I don't know the right answer, but assuming a maximum signal of maybe 100 millivolts would be a good start. You might want to use two amplifiers in parallel with different gains to give you more range (which will eat both channels for one sensor, of course). Also take a look in the archives for discussions of frequency compensation to lower your effective frequency response. ---------------------------------------------------- Doug Crice e-mail dcrice@............ GeoRadar Inc. web site http://www.georadar.com 19623 Via Escuela Drive phone 1-408-867-3792 Saratoga, CA 95070 USA fax 1-408-867-4900 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: lahr@.................. Subject: Re: First Quake? Date: Thu, 29 Jan 1998 16:21:35 -0700 (MST) Pete Fleming wrote: "... The event arrived at my location at 23:53:00, about 24 minutes later. I am in San Jose, CA Is that about the correct time of arrival?" Pete, You can use this web site to find out when seismic phases from a specific earthquake are due to arrive at your seismic station: http://www.aeic.alaska.edu/lahr/compute_tt.html Or, to check on the arrival times from the recent earthquakes listed in one of the finger servers, use: http://www.aeic.alaska.edu/lahr/artim.html 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://www.aeic.alaska.edu/lahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: kathy mortensen Subject: Re: First Quake? Date: Thu, 29 Jan 1998 21:08:29 -0700 lahr@.................. wrote: > > Pete Fleming wrote: > > "... The event arrived at my location at 23:53:00, about 24 minutes later. > I am in San Jose, CA Is that about the correct time of arrival?" > > Pete, > > You can use this web site to find out when seismic phases from a > specific earthquake are due to arrive at your seismic station: > > http://www.aeic.alaska.edu/lahr/compute_tt.html > > Or, to check on the arrival times from the recent earthquakes listed > in one of the finger servers, use: > > http://www.aeic.alaska.edu/lahr/artim.html > > 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://www.aeic.alaska.edu/lahr Hey, these are cool sites and I'll be using them but they return different deltas and azimuths for the same event!!! Anybody have a clue????? I was checking the mariana event 23:29:43 One gives delta of 86.20 and azimuth of 308.8 the other gives delta of 33.13 and azimuth of 326.2 The P for the first was for 23:42:20 the P for the second was for 23:36:16 SKM (Stephen) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: kathy mortensen Subject: BIG OOPS Date: Thu, 29 Jan 1998 21:54:08 -0700 Found my mistake!!! I'm used to the convention of WEST being POSITIVE!!! %$#$%$#$% fine print!!!! SKM (Stephen) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Bob Fryer Subject: Re: Volcano Erupts off Oregon Coast Date: Fri, 30 Jan 1998 03:10:13 -0800 Hello Charles, Certainly the "Rivers of molten magma" comment is inappropriate in a "news" story. Actually, "....other researchers say it's likely that rivers of red-hot lava are flowing out of the volcano...." were the words, which were likely the writer's paraphrasing of the actual comments. However, to me, your comments are also ill advised and based on insufficient information. Note that NOAA's program for this location includes a large acoustic element from the Navy SOSUS technology, the development of which has passed the fifty year mark. The Navy technology was developed to locate and identify EVERY acoustic source in the sea. Therefore, if people in the NOAA program say that lava is flowing, believe them. Only the writer's graphic description should be questioned, as you well know the formation process for pillow lava. Charles, I sincerely enjoy reading of your considerable efforts and expertise, as chronicled here and elsewhere. Below, is a report of the 1993 events, with the URL. Take care, Bob Fryer ------------------------ [Image] The CoAxial "Story" http://www.pmel.noaa.gov/vents/coax/story.html -------------------------------------------------------------------- The CoAxial Segment had a well-documented dike injection and eruption episode in June-July of 1993 which was detected and monitored by the NOAA/Navy real-time T-wave monitoring system. Two "event plumes" were found over the axial valley centered around 46=B0 30'N where the T-waves had concentrated during the latter part of the episode. This site (which subsequently was known as the Flow site) became the target for dives with the Canadian remotely operated vehicle ROPOS off the NOAA R/V DISCOVERER in mid-July, 1993, during which a fresh, venting lava flow 2.5 km long was discovered, mapped and sampled. The lava flow was erupted on a ridge just north of an older volcano cone on the median volcanic ridge. Extensive venting was also found southward from the cone for about 4 km within a small graben. ROPOS recovered rock samples, some water samples, and took temperature measurements. Subsequent NSF/NOAA Alvin dives in October, 1993 (J. Delaney and R. Embley, Co-Chief Scientists) recovered several high quality vent fluid samples and left prominent markers at the sample sites. A magnetics and gravity survey was also conducted at the Flow site during the October dive series (P. Johnson, M. Tivey, and M. Holmes P.I.s). --------------------------------------------------------- You said, >I find it interesting that the news article jumped on the "massive >submarine volcanic eruption" story with only seismic data to justify its >origin. > >Yes, it is suggestive, but not conclusive. There have been many seismic >swarms recorded around volcanos before without even the hint of an >eruption - more recently, the Long Valley caldera at Mammoth Lakes. > >No doubt, an excursion similar to that of the Northern Gorda Ridge event >would provide more conclusive evidence, the sooner the better. > >"Rivers of molten magma" -- indeed! > >-- >---/---- >Charles P. Watson, Consulting Geologist >Advanced Geologic Exploration >Seismo-Watch / Earthquake Information Services >Voice: 702-852-0992 / Fax: 702-852-3226 >Office Location: 39.43N 119.71W >mailto:watson@................ >http://www.seismo-watch.com ----- earthquake WARNING research ----- --- animals, people, scientific evidence --- --- http://www.teleport.com/~bfryer --- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Volcano Erupts off Oregon Coast Date: Fri, 30 Jan 1998 08:27:53 -0700 Bob Fryer wrote: > > Hello Charles, > > Certainly the "Rivers of molten magma" comment is inappropriate in a "news" > story. > Actually, "....other researchers say it's likely that rivers of red-hot > lava are flowing out of the volcano...." were the words, which were likely > the writer's paraphrasing of the actual comments. > > However, to me, your comments are also ill advised and based on > insufficient information. Note that NOAA's program for this location > includes a large acoustic element from the Navy SOSUS technology, the > development of which has passed the fifty year mark. The Navy technology > was developed to locate and identify EVERY acoustic source in the sea. > Therefore, if people in the NOAA program say that lava is flowing, believe > them. Only the writer's graphic description should be questioned, as you > well know the formation process for pillow lava. Humm....According to Chris Fox, Principal Investigator for this project, the news article was incorrect in their statements and he was not quoted in saying "Rivers of Molten Lava." He is a little pertubed at what they said. All the seismic information is suggestive and not conclusive. Nobody has trolled the site and collected samples. Sometimes pumice fragments floats to the surface when these submarine eruptions goes off and their have been no reports of this nor of dead fish either. You would be correct about the pillow lavas being formed "if" magma would make it to the surface. If you read the pages on the Northern Gorda Ridge event, you'll get a feel for what it takes to confirm the eruption. It is unfortunate an excursion could not be launched when the event first happened. It seems to be dwindling down now. I saw NSF approved funds for an excursion in md Feb. Let's cross our finger for a confirmation!! Based upon the trend and volume of seismicity, I would suspect a diking event. Whether this activity made it to the surface of the ocean floor will be the focus of the excursion. Thanks for your kind comments on my work. One of the things I have learned about reporting in the geologic media is confirming the information first. Talk to the people who know the most and pick their brains. They are, like you have indicated about the PMEL program, the experts. And, this would be the third "volcanic" event noted on record, if confirmed. While the Axial seismic sequence is similar to the previous two, one can arm wave all they want about what could be happening. Although I have long arms and can wave with the best of them, I try not to flap so much to loose a grasp of terra firma and the principals of proper geologic research. Cheers mate! -- ---/---- Charles P. Watson Seismo-Watch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Big quake in Chile Date: Fri, 30 Jan 1998 09:09:28 -0700 Just received the Harvard and Caltech CMT's: Mw 7.0 This is the 2nd M7 this month and the 15th M6+ for January, tying it with January 1995 for the most active January in the 1990's. Least active? Jan 1992 with only 3 M6's. Tally-ho! -- ---/---- Charles P. Watson Seismo-Watch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: kathy mortensen Subject: CHILE Date: Fri, 30 Jan 1998 09:43:32 -0700 A nice waveform recorded from CHILE at 12:28:17 UTC with a 2.7 mixed in with it at around 12:31:?? (the S part anyway) from near MAMMOTHS!!! SKM (Stephen) lat./long. 38.828N / 120.978W _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "frank murray" Subject: RE: Big quake in Chile Date: Fri, 30 Jan 1998 10:38:30 -0800 > Just received the Harvard and Caltech CMT's: Mw 7.0 > > This is the 2nd M7 this month and the 15th M6+ for January, tying it > with January 1995 for the most active January in the 1990's. hi charlie, from which catalog are you getting the number "15" ??...i just checked the cnss catalog and they only list ten (10) M6+ january quakes prior to this last one...is there a more accurate single source than the cnss??...if so, have you the url??... thanks, frank _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Big quake in Chile Date: Fri, 30 Jan 1998 12:32:20 -0700 Oh golly Frank, I use QED listing for NEIC and Harvard Moment magnitude anlayses here: http://wwwneic.cr.usgs.gov/neis/weekly/qedevents.txt I see some of the preliminary Mw's have been redetermined at less than Mw 6.0. Nevertheless, I have the following 12 events: 1/30 Foothills of Northern Chile Mw 7.0 1/27 Tonga-Fiji Islands Mw 6.5 1/19 Off the coast of Southern Chile Mw 6.2 1/14 Fiji Islands Mw 6.5 1/12 Fiji Islands Mw 6.7 1/12 Foothills of Central Chile Mw 6.2 1/10 Near the Coast of Guatemala Mw 6.5 1/10 South-Central Peru Mw 6.4 1/04 Loylty Island Region Mw 7.4 1/03 Southern Mid-Atlantic Ridge Mw 6.3 1/01 Along the East Coast of the Kamchatka Peninsula Mw 6.0 1/01 Volcano Islands Region Mw 6.4 By the way, there is a great report on the 1995 Antofagasta Mw 8.0 earthquake in BSSA Vol. 87, No 2, pp. 427-445, April 1997. The focal depth of this recent quake (NEIC: 48 km; revised) suggests a deepening of the 1995 rupture plane surface along the Nazca-South American plate boundary, thus put more strain on the 1877 seismic gap north of the Mejillones Peninsula and increasing the already high chances for reactivation across this locked segment. Eeek! One to watch in the "near" future. -- ---/---- Charles P. Watson Seismo-Watch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Need ideas on crawlspace dampness Date: Fri, 30 Jan 1998 15:23:14 -0700 Hi group, Have decided to redo my "vault" in the crawlspace. The vault "floor" is clay. When the door is shut, the ground gives up alot of moisture, whereas the rest of the crawlspace is fairly dry. The vault walls are insulated with common household insulation, and the inside walls are covered with sheet metal. There is no vent mechanism at the present. With this as a description of the vault at the present, what may help ease the amount of moisture but at the same time keep its isolation of temperature extremes? My planned improvements are ac power lines, paint, and misc. Would a ground cover of plastic sheet near the piers really solve the moisture or just help build it up? Suggestions welcome. Or is it something that I would have to live with, for best seismic results? Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Ms 6.4, Chile Date: Fri, 30 Jan 1998 16:25:12 -0600 (CST) It definitely doesn't look like a 7 from here, which is why there is s lot of discussion about the difference between Ms and Mw. NEIS lists: 98/01/30 12:16:09 23.51S 69.83W d 43.7km Ms 6.4 Northern Chile Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Mw 7.0 Chile, NEIC Date: Fri, 30 Jan 1998 15:16:19 -0700 30JAN98 NORTHERN CHILE (REVISED) Date: Fri, 30 Jan 1998 11:41:46 -0700 (MST) From: Stuart Sipkin To: sipkin@.................. 98/01/30 12:16: 9.43 NORTHERN CHILE (REVISED) Epicenter: -23.510 -69.832 mb 6.3 MS 6.4 MOMENT TENSOR SOLUTION Depth 48 No. of sta: 57 Moment Tensor; Scale 10**19 Nm Mrr= 2.51 Mtt= 0.03 Mff=-2.53 Mrt= 0.51 Mrf=-2.44 Mtf=-1.09 Principal axes: T Val= 3.71 Plg=63 Azm= 58 N -0.01 18 187 P -3.71 20 284 Best Double Couple:Mo=3.7*10**19 Mw=7.0 NP1:Strike= 41 Dip=30 Slip= 128 NP2: 179 67 71 ---#### -------########## --------############# ----------##############- -----------################-- ------------################--- - --------#################-- -- P -------####### ########--- -- -------####### T #######---- ------------####### #######---- ------------################----- ------------################----- ------------##############----- ------------############------- -----------##########-------- ----------#######-------- ---------##---------- #######---------- ####--- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: Need ideas on crawlspace dampness Date: Fri, 30 Jan 1998 07:20:12 -0800 Hi Most commercial buildings use plastic with 1-2" of sand over and topped with 4" of concrete. A little expensive but it works. Barry meredith lamb wrote: what may help ease the > amount of moisture but at the same time keep its isolation of > temperature extremes? > > My planned improvements are ac power lines, paint, and misc. > > Would a ground cover of plastic sheet near the piers really > solve the moisture or just help build it up? Suggestions welcome. > > Or is it something that I would have to live with, for best > seismic results? > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jim Hannon Subject: Re: Need ideas on crawlspace dampness Date: Fri, 30 Jan 1998 20:20:11 -0600 meredith lamb wrote: > > Hi group, > > > > Would a ground cover of plastic sheet near the piers really > solve the moisture or just help build it up? Suggestions welcome. > > Or is it something that I would have to live with, for best > seismic results? > > Thanks, Meredith Lamb > > The former owners of my house covered the entire dirt floor of the crawl space with a sheet of plastic. At least it doesn't seem to be hurting anything. -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Saving quake in SDR Date: Fri, 30 Jan 1998 21:39:31 -0500 Larry, A problem with SDR:My records are all Chan. 1. If I set REPLAY to Chan= 1, 1/28/98 and 02:00 and set it to save 240 mins, it displays ~ 3 hrs. OK= but then switches to a new screen and sez "file CHAN9.028 not found". I= f I do REPLAY again, it shows the channel set to 9 or 56 or something other= than 1. (Of course, I then set the channel back to 1.) It seems that a day's record ends at 04:59 and REPLAY (or SAVE)will not= go to the next day. How can I save a segment of the data which extends across the 05:00 boundary? Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ted Blank Subject: Re: Need ideas on crawlspace dampness Date: Fri, 30 Jan 1998 19:35:56 -0800 (PST) You solve crawl space dampness with a two-pronged approach. 1) reduce or eliminate infiltration of moisture, and 2) increase ventilation to get rid of whatever does enter. Place a thick layer of "visqueen" (construction plastic) on the ground, overlap the edges and seal them to each other with hot glue or a thin layer of other adhesive. Put some pressure treated 2x4's around the edges to keep them flush with the foundation. Then open up the screening on the ventilators or add some if you don't have any. Just putting a partial covering on part of the dirt will be a disaster since the moisture will condense on it and it will end up with puddles all the time. Regards, Ted > > meredith lamb wrote: > > > > Hi group, > > > > > > > > Would a ground cover of plastic sheet near the piers really > > solve the moisture or just help build it up? Suggestions welcome. > > > > Or is it something that I would have to live with, for best > > seismic results? > > > > Thanks, Meredith Lamb > > > > > The former owners of my house covered the entire dirt floor of the crawl > space with a sheet of plastic. At least it doesn't seem to be hurting > anything. > -- > Jim Hannon > http://soli.inav.net/~jmhannon/ > 42,11.90N 91,39.26W > WB0TXL > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: Need ideas on crawlspace dampness Date: Sat, 31 Jan 1998 00:13:58 -0600 (CST) Meredith, Certain universal criteria define the optimal location for seismic stations or vaults. The biggest poison ivy patch in the county is always the quietest site, and the wettest hole in the earth is where the vault or pier should be. My favorite locations are mines and caverns with dripping ceilings and seepy streams. Lacking these, I dig a deep pit, like the 10 meter pit in my back field here; at least I didn't hit the water table, which ruins the whole thing. I ususally take both a defensive and an offensive approach toward moisture problems. Defensive means sealing everything so that it can be desiccated. For electronics like amplifiers, VCOs, VHF transmitters, etc., I am a great user of tupperware, sealed storage boxes, and RTV silicone sealant. Most poly enclosures can be sealed with RTV, which will cure and stick quite well, but can be pealed off easily if the container has to be reopened. We use cheap desiccant (packaged anhydrated diatomacious earth; 1/10 the cost of silica gel) in everytinng, and "humidial" indicator strips visible through the box to tell that the electronics is in fact dry. THe cables or wires are fitted through small holes and also sealed with RTV. (The mug shot of me on the web page shows my hand stuck in the PVC "pipe vault" that housed the electronics cannister along with about 10 units of desiccant and an RTV seal under a hubless clamp; this was buried in the ground, and stayed dry for up to 4 years in the Aleutians). For larger work areas, as in the caverns, I have found that the large poly truck tarps provide good control of floor moisture (assuming the cieling drips are diverted). These are ususally orange or blue, and are tough enough to take a lot of walking on. In the CCM cave, I have two 20 x 30' on both sides of the piers; the clay floor under them has slowly dried out over the last ten years. Ventilation and or dehumidification presents both temperature and noise problems for the seismometer. At a large (50' x 100') underground munitions bunker near here that I use for storage of antiquities and testing new instruments, I have to use a large commercial dehumidifier to control the moisture; it makes considerable high frequency noise, which is isolated from the floor by vibration isolation damper pads. But a really small Sears dehumidifier makes such high frequency noise that it is outside the passband of the instruments. I use one in the 1923 SLM vault under the Univ gym; in the summer it presents a heat problem, since the vault is sealed quite well. Maybe these will give you some ideas. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: STM-8 main spring vibration damping Date: Fri, 30 Jan 1998 23:35:42 -0700 Sean, Previously in a msg you mentioned the desire to find a good method of main spring vibration damping. Of course this is separate from the electronic damping already in the circuit. My curiosity is getting too me, as I can only think of perhaps dunking part of the main spring in a container of some kind of oil; which would have to include the lower flexure/base, with suitable oil proofing to prevent leakage. Is this perhaps the only idea that has been entertained, or is it even feasible, or the only likely cheapest solution? I suppose you could even add on a heater in the damping bath, which could regulate temperatue in the whole seismometer. Just speculating. I can't see how any kind of eddy current method could be involved with the magnetic spring...even with long extensions.. the weight of which would change the desired spring functions. I can't see how even magnetic repulsion would be feasible, with again likely added weights being an influence on the spring and the magnetic fields likely interfering or bucking spring action. There are other things like more added electronic feedback schemes involving the spring. I think your design will eventually be more of a mainstay design and hence....I feel like the question will arise anyway. More than likely than is no real need for such....now....but I can't help but wonder.....what if?...and....what are your thoughts? Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Arie Verveer Subject: Chile - File Date: Sat, 31 Jan 1998 16:43:53 +0800 Hi All Sorry about the large file sent to "event@.............". Next time I'll cut down the samples per second. Just getting my sea legs. Arie ajbv@............ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: SW6079@....... Subject: Trials of an Amateur Seismologist Date: Sat, 31 Jan 1998 10:35:52 EST After reading Meredith Lambs' interesting story, I felt that a few of the readers of this list might enjoy reading of my rebuilding of a surplus chart recorder. I purchased a real gem from a local electronic/antique shop in Seattle for 10 dollars. It had everything, Unbelievable sensitivity (down to 1 millivolt) Numerous inputs, attenuating networks, infinitely adjustable chart drive. And external time-base input as well. In short everything I wanted. Only problem (I thought) was that it didn't work. Making a very long story short. I finally succeded after about 15 hours work in getting the thing working. When purchasing it I gave little thought to chart paper (How much could that be, Right?) Then reality struck, Turned out there was only one supplier in the U.S. a years supply would run me about 3,600 dollars... Fortunately, I haven't lost my sense of humor. Hmmm.... Well, I learned a whole lot about chart recorders in the process anyway, and am presently scraping together enough equipment to use with my homebrew Lehman. I was donated an old 386 w/ 400 meg HD and will possibly purchase one of Larry's boards. If there is someone out there who might be willing to lend a little tech assistance, I would be very grateful. Thanks, Mike Sellman. sw6079@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Have another Breckenridge, Colo Meteor! Date: Sat, 31 Jan 1998 11:17:30 -0700 Yea I know! You're saying to yourself,..You have got to be kidding!. I felt the same way myself when I read of it in the Denver Post newspaper Friday...3 days late. This is getting to be too much...but I hope some of you...have a "falling" interest. Rough excerpt: A second fireball was observed about ~9 pm, near Breckenridge, traveling east to west, with smoke trailing it on Tuesday Jan 27th...about 9 hours after the first meteor, which is attracting considerable national attention it seems. No mention of either Breckenridge meteor having sounds. The Denver Museum of Natural history is investigating all 3 meteors now. There have been no reports of any meteors fragments being found. According to a Doug Revelle at Los Alamos National Laboratory...."the key to it is the smoke... that means its very big". There is no retraction, addition or etc., in todays Denver Post. I suppose you are really wanting my personal opinion on all of this. I admit I made fun of the first (Colo. Springs), and somewhat implied humor on the 1st Breckenridge meteor. Well I'am really trying to still restrain myself from injecting any humor on this one also. Hmmm, you know there is a law against making fun of vegetables in the U.S., that was passed a number of years back and I'am not so sure it applys to meteors legally. I hugged my tektite yesterday. I think I can understand why the Denver Post delayed the report of the 2nd Breckenridge meteor. However...I have my own theory......The Overland Stage between Breckenridge and Denver was delayed due to falling rocks. Or....these "watch for falling rocks" signs in the mountains was observed too well. Also there is signs denoting fines for littering, and no fires/smoking. OPPS! Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: Need ideas on crawlspace dampness Date: Sat, 31 Jan 1998 12:51:04 -0700 (MST) On Fri, 30 Jan 1998, meredith lamb wrote: > Have decided to redo my "vault" in the crawlspace. The vault > "floor" is clay. When the door is shut, the ground gives up alot > of moisture, whereas the rest of the crawlspace is fairly dry. > The vault walls are insulated with common household > insulation, and the inside walls are covered with sheet metal. > There is no vent mechanism at the present. With this as a > description of the vault at the present, what may help ease the > amount of moisture but at the same time keep its isolation of > temperature extremes? Meredith, you could dump some kitty litter in there to absorb moisture from the ground, and maybe some hydroscopic pellets on top (I am not sure what we use but it is put into dessicators to keep the air dry). ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: STM-8 main spring vibration damping Date: Sat, 31 Jan 1998 21:55:59 -0600 (CST) Meredith, The damping of the suspension spring has been a plague for seismologists since day one, and has seriously limited the performance of vertical sensors. One of the benefits of a leaf spring is that its' natural resonances are usually outside of the passband of the sensor, and can theoretically be ignored. But any accelertions that excite the spring, if they are strong enough to get it ringing, will excite modes that will change the geometry of the spring and change the forces acting on the boom and show up in the output. This is why most coiled spring verticals have trouble being converted to VBB performance; ringing effectively shortens the spring and raises the mass. In commercial leaf-spring seismometers, the geometry, clamping, and damping of resonances are tightly guarded trade secrets. And because of the desired bandwidth of a VBB instrument, we need a linear response to strong local accelerations. For the STM seis, resonance of the spring has been one of my major concerns. In the original prototype, some damping was afforded by friction at the upper pressure bar under the boom. This was also a cause of noise, and I have replaced it with a convex glass surface (I DO need to document this), so now there is no friction to damp the spring, which resonates at 50 hz. I had temporarily installed an oil dashpot for damping (a plastic sewing machine bobbin attached to a brass rod to one of the holes in the side of the spring, with the bobbin immersed in a small amount of olive oil in a pill jar). It was somewhat effective, but potentialy messy, and added weight to the spring. But eddy current damping is preferred, since it is a true velocity effect. So I installed 6 of the very small rare-earth magnets that RS sells in a line across the bulge of the spring by just letting them attach themselves to the steel; I marked all of them for the same polarity beforehand. Then I installed a 1/4" thick aluminum plate about 0.5 mm from the row of magnets, and this damps the spring. 6 magnets and aluminum plate do not critically damp the oscillations; they still persist for a fraction of a second; but I didn't have any thick copper on hand (maybe tomorrow); also, there is room for at least six more of the little magnets. They are so small that they do not appreciably add to the mass of the spring/boom. You can demonstrate the eddy-curreent damping of these strong magnets by setting a piece of thick aluminun at an angle and letting them slide down. The better the induced eddy currents, the slower they will slide. I will keep you posted on further evaluations along this line; I also need to test my old SLR camera with the closeup lens so I can get photos of these details posted on the web. (I also need to send you polaroids of the S-5000 LP seis VBB). Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Temp Control in sealed vaults Date: Sun, 01 Feb 1998 10:19:43 -0700 Sean-Thomas, Your method of using a dehumidifier in sealed seismo vaults, sounds very interesting too me, as it sounds like a good solution along with a slew of your other suggested dampness controls. Naturally, I have to think, that if such a dehumidifier were present in the "vault", that with rheostats, relays, etc., that comprised a on and off control for the dehumifier, that this would help alot in the temperature control aspect of the vault and more or less present an ideal total package. So....if the environment is relatively stable temp wise,....so should the seismometers therein....I would think? I've never used a dehumidifier in a vault before....and outside of that as a possible humidity/temp control device....are there other means that you are aware of that can help? Most older seismometers are relatively non heat generating (coil-magnet) sources. Your vertical seismometer s/c may be a generator of sorts....or is it insignificant? Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: rare earth magnets Date: Sun, 1 Feb 1998 11:53:51 -0600 (CST) Meredith, THe rare-earth magnets are RS #64-1895, at $1.59/pair. They are about 2mm dia by 1 mm thick, and weigh perhaps 4 grams. Their surface strength is listed at 10 800 gauss, or about twice that of most ceramics. Their polarity is not marked, so I just put an X on one of them and then found the side of the others that repulsed the X side, and marked them with an X. Then they are installed with all the X to the same side, about 1 cm apart. This maximizes their exended field when used in a parallel arrangement. For damping with an eddy current plate, I found little difference in their sliding down a piece of 1/8" aluminum bar wrt 1/4" bar, but there was definitely less of an effect with 1/16" bar. The effect should increase about 60% with a copper bar, since Al has 1.6 times the resistance as Cu. As for other improvements for the seis, I'm going to try to use 1/2" threaded stainless steel rods to support the hinge plate, rather than aluminum, which has about twice the thermal coefficient as steel. I want to increase the working range to +,- 5 deg C; right now a 1 deg C change requires re-zeroing. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: Temp Control in sealed vaults Date: Sun, 1 Feb 1998 12:12:31 -0600 (CST) Meredith, The best solution to any problem is the simple one. For a seismograph vault, I believe that passive control of humidity and temperature are preferred, and the use of active devices like a dehumidifier should be a last resort. The dehumidifier makes a lot of heat, and for unattended operation the condensate needs to be disposed of via a hose to the outside. Passive desiccation of sealed electronics is relative easy, but the humidity has to be monitored with either Humidial strips or cheap hygrometers. Passive desiccants can only soak up about a teaspoon of water per package (about 2 ounces) of desiccant. The stuff I use, "Humisorb", from Culligan, comes in 1 "unit" bags in 5 gallon pails of 300 bags, and can be re-activated by baking in an oven (carefully: the paper bags can be burned). As for heat from the STM-seis electronics, the 12 volt power supply is the major source of perhaps 5 watts; no part of it gets more than warm to the touch, although last fall I found a juvenile copperhead snake curled up around the transformer. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Black Body Radiation Seis/Vault aspects Date: Sun, 01 Feb 1998 11:35:46 -0700 Sean-Thomas, I'am sitting here looking at a possible square aluminum mast for your vertical seismometer. Its painted black. As I recall other commercial seismometers, they are usually black also, especiallly in the last few decades. Older seismometers are usually gray. I'am not really all that up to thermal radiation aspects, and were it involves temperature aspects. I'am aware of your steel and preferable stainless steel components on the vbb seismo. Anyway....given your total choice of total of paint for the seismo....and inside vault wall....and even outside paint walls.... would your choice be black for the seismo, inside vault wall, and maybe (?) white on the outside wall for thermal considerations? I would be the first one to find humor in this aspect, I suppose, but what the heck....if the seismo is buried in a vault, it would seem more sensible to consider it more seriously, especially if it could mean the difference in afew degrees, and problems down the road. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Rare Earth Magnets & Copper plate/s Date: Sun, 01 Feb 1998 12:40:56 -0700 Sean-Thomas, Your projected 1/4" thick damping plate which is mounted across the horizontal magnets as one piece.....what if?....... there were a number of vertical bars of copper placed in front of all six magnets? Say....~/2" width X 1/4" thick X ~ 6" long. Would the effective damping show an increase....or would it make any difference...versus...one big plate of copper? Why do I ask... I do have afew copper brackets like that, but not wide plates. With another row of magnets, the vertical strips might be easier to bend versus the single plate, to adjust the circular spacing difference over the possible 2 (?) "rows" of neodymium (?) magnets. I don't know, if 6 "plates" would be better than one plate, but it seems an interesting speculation. I suppose it opens a can of worms over effective eddy current damping, per given area , per magnet, which I know zero about. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: Black Body Radiation Seis/Vault aspects Date: Sun, 1 Feb 1998 15:20:05 -0600 (CST) Meredith, I don't think that paint color will have much to do with seismometer thermal stability, since there are no significant sources of heat radiation to deal with. Actually, the biggest heat source is the person adjusting the seis, and the blued leaf spring is a big absorber. When I open the box here to adjust the seis, if I am not quick about it, it drifts down from warming up, then drifts back up after I close the box. The early seismometers, galvos, etc, were all painted black because they were usually in the same room as a photographic drum recorder, and any possible reflections of the galvo illumination lamp had to be minimized. The walls of old vaults, like our 1923 vault under the gym, were usually painted dark red, which appeared black when the only light in the vault was a ruby glass photo darklight. For a new vault, I think bright colors on the inside help with visibility. For the outside, I would use 'Reflectix" (aluminized bubble insulation: at Bldrs Sq.) or aluminized cellotex, or whatever to slow down radiative heat flow. ALSO: be sure to use compact flourescent lamps for illumination, since they produce very little infrared energy. Regarding eddy current damping: any arrangement of the conductive bars, Al or Cu, will work. The volume of the current induced by the relative motion of the magnet is probably not much more than twice its' size. The only problem I see with your row of vertical bars is getting them all lined up so you can get an even spacing from the convex surface of the spring where the rare earth magnets are. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: George Harris Subject: Re: Black Body Radiation Seis/Vault aspects Date: Sun, 01 Feb 1998 13:34:13 +0000 meredith lamb wrote: > > Sean-Thomas, > > I'am sitting here looking at a possible square aluminum mast for > your vertical seismometer. Its painted black. As I recall other > commercial seismometers, they are usually black also, especiallly > in the last few decades. Older seismometers are usually gray. > Based on my "long ago" study of heat transmission by radiation and conduction the following generally apply. 1. Unless there is a substantial temperature difference between source and it's surroundings, color is not really very important. The convection transfer is much higher at normal temperatures. If the temperture of the contents of a box are near the same as the inside of the box there is negligable transfer by radiation. 2. Extra mass inside of a well insulated enclosure has the best temperature stability. Styrafoam is about the best insulation. 3. The best system has a good mass inside an insulated box with another insulated cover and temperature control inside the outer box. George Harris _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: new stations added to map Date: Mon, 02 Feb 1998 13:57:03 +1200 hi all, sorry for the delay, i have really been busy since the start of the new year, but i have finally had a chance to add the the maps and database the info sent of from these stations NAME: Arie Verveer Western Australia NAME: LIBERIO ROSSI ITALY NAME: PAOLO FREDIANI ITALY NAME: CLAUDIO CONTI SICILY NAME Stephen Mortensen Calif. NAME Stephen Caruso Ohio NAME: Douglas McConnell NSW, Australia With these additions we now have 59 ststions in the database WELL DONE people this is truely a worthy listing of station info giving new comers a wide range of options and ideas to choose from when setting up their own seismograph system. Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Fontana Trend is on the Map! Date: Sun, 1 Feb 1998 18:00:18 -0800 (PST) Hello All: I found this nice graph and a map that shows the Fontana Trend and all of the recent seismic activity near San Bernardino, CA. http://www.scecdc.scec.org/pictures/chino98.gif Best Regards, Frank Condon mail to: frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Mike Stickney Subject: Re: Temp Control in sealed vaults Date: Mon, 2 Feb 98 13:20:36 MST Meredth and Sean-Thomas: Back when I was a student at Univ. of Montana, the World Wide Seismograph Station MSO experienced humidity (actually water) problems in its underground vault. We used dessicants but had to change them frequently (weekly). The campus physical plant was enlisted to install a dehumidifer/heater system to control the moisture problem. The system sucessfully controled the moisture problem but in the process drove the long period instruments completely off scale each time the system switched on or off. The system worked but could not be used because of its effects on the instruments. The ultimate solution involved the installation of two ventilation pipes, perhaps 4 inches in diameter, that allowed passive air circulation through the instrument room of the vault. -Mike Stickney Montana Bureau of Mines and Geology Butte, MT _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: Questions About STM-8 Boom Date: Mon, 2 Feb 1998 14:19:40 -0600 (CST) Warner, The mass at the END of the boom consists of about 1 lb of lead plumbing bars plus the weight of the feedback coil assembly. To determine the effective mass, I substute brass weight set weights for these until the boom balances, and get just about 0.5 kg for the real mass. There are 2.2 lbs per kilogram, so this is about 1.1 lbs. This is not technically "mass", as in F=m*a, but the habit of calling a weight in a seismometer a "mass" dates to 1909. So the inconsistency is consistent. The mass of the boom itself is about 50 grams: it is made of Al channel, 3/4" w x 1/2" deep x 1/16" thick. The spring constant of the leaf spring does not need to be known, since it is not used in the transfer function at all. The only impact the spring has is on the mechanical period. By placing a stronger spring close to the hinges, we get a minimal change in force for any movement of the mass, which translates into a longer period. The trade off is the Quality factor, which needs the product of the period x the mass to be greater then 1. A stable design is all that is required. The beauty of the VBB transfer function is that the spring constant, the hinge elasticity, etc., are not used. THe mechanical constants are: To (seconds), M (kg), r (the displacement transducer; mv/micron), and G, the feedback coil constant. (Newtons/Ampere), and the coil resistance (8 ohms for the speaker). The original MATHCAD document can be found at: http://www.eas.slu.edu/People/STMorrissey/etc_export/tstvbb08.mcd, I don't know if matlab will read it; there is also an .rtf version "tstvbb08.rtf" in the same directory. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: USGS Database Program Date: Mon, 02 Feb 1998 13:00:42 -0800 Paul, sorry I can help you. I have forwarded your message to the PSN mailing list. Maybe someone there can help. PSNers, if you can help please contact Paul directly since he is not on the list. His address is paul@.................... Thanks, -Larry At 07:50 AM 2/2/98 GMT, you wrote: >Hello Larry! > >I saw your name on the PSN web page and on the FAQ's, so I am hoping you >might be able to steer me in the right direction. > >I have the USGS/NEIC Global Hypocenter Data Base Version 3.0 CD-ROM. The >program EPIC2 worked great with my old computer running DOS but refuses >to work with my Windows 95 new computer. It will not run in either a DOS >window, or by starting the underlying DOS only. I tried calling Glen >Reagor at NEIC and got a response from someone else saying that this >program is no longer supported, you don't need to call again. Do you >know of anyone who has written a Win 95 program to access this database? >It is either find some kind soul who has done the work, or translate the >old Fortran list from the back of the book, to something my computer can >use (along with learning a new programming language...). > >Thanks for your time. > >++++++++++++++++++++++++++++++++++++++++ >+ Paul R. Jorgenson KE7HR NSS 39382 + >+ Phoenix, AZ - No caves to speak of + >++++++++++++++++++++++++++++++++++++++++ > > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: Questions About STM-8 Boom Date: Mon, 2 Feb 1998 21:10:46 -0600 (CST) Warner, The world of seismology has tried for years to work out data amplitude compression schemes, like logrithmic, gain ranging, etc, but they either trash the waveforms that are telling us about the earthquake source and the earth between the quake and the receiver (seismograph), or they put glitches and discontinuities in data. The best scheme has been the 24-bit EDME encoder, which is really a vastly oversampled 16-bit DAC that can add bits both sides of the LSB as its analog range approaches the MSB, then decimates the sample rate and uses digital FIR filters to clean it up. Unfortunately, these are pricy instruments; the best commercial system uses a 68020 DSP for EACH channel of the data streem. Some newer entries get it all done on one chip. This gives us the dynamic range that earthquake recording needs. A good seismometer can resolve a nanometer/second of ground velocity at the earth's background noise level, but a local quake can push a centimeter/second. A VBB instrument might produce 40 volts peak at 1 cm/second, meaning that the nanometer/second is 4 microvolts, a range of 10^7, or 140 db. But in reality, maybe 0.1% of the time is such range actually needed; on the other hand, I have yet to see a VBB 24-bit system clipped in the ADC. This is why the VBB feedback has no active devices in the loop that would limit the dynamic range, and the displacement xducer has nanometer (aka infinite) resolution. BTW; most commercial VBB sensors use capacitive sensors, but are top secret about the geometry needed to produce linearity. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: NAME Subject: Something Big Date: Mon, 02 Feb 1998 22:26:28 -0500 Time is 03:36 UTC on 2/3/98. Large amp waveforms have been arriving for about 20 minutes. If I read this right the s-p difference is about 3 minutes in Raleigh, NC. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: Something Big Date: Mon, 02 Feb 1998 08:45:06 -0800 Name I have received some large amplitude waves here in Calif. at about the same time but we are having windy storms here so it is hard for me to distinguise the waves from wind in the trees. Barry NAME wrote: > > Time is 03:36 UTC on 2/3/98. Large amp waveforms have been arriving for > about 20 minutes. If I read this right the s-p difference is about 3 > minutes in Raleigh, NC. > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Tom Frey" Subject: Re: Something Big Date: Mon, 2 Feb 1998 19:51:59 -0800 Arrival time 03:09:15.6 here in Washington State if it's the same event tom _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "frank murray" Subject: RE: Something Big Date: Mon, 2 Feb 1998 20:27:02 -0800 near oaxaca on the coast of mexico: 98/02/03 03:01:59 15.94N 96.11W 33.0 6.1Ms A NEAR COAST OF OAXACA, MEXICO > -----Original Message----- > From: Tom Frey [mailto:tfrey@............ > Sent: Monday, February 02, 1998 7:52 PM > To: PSN-L Mailing List > Subject: Re: Something Big > > > Arrival time 03:09:15.6 here in Washington State > if it's the same event > > tom > > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "John Krempasky" Subject: Re: Something Big Date: Mon, 2 Feb 1998 23:59:37 -0500 Mexicans have it thus: sismo mas reciente 98/02/02 21:02:01 Lat: 15.74 Lon: -96.44 Prof: 23 km Mag: 6.4 Epicentro: COSTA DE OAXACA Map is directly on the coast. That's exactly where Pauline struck last year, too. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: kathy mortensen Subject: Re: Something Big Date: Mon, 02 Feb 1998 23:04:45 -0700 NAME wrote: > > Time is 03:36 UTC on 2/3/98. Large amp waveforms have been arriving for > about 20 minutes. If I read this right the s-p difference is about 3 > minutes in Raleigh, NC. Just checked my recorder, the mexico event left it's mark here in Pilot Hill calif. at 3:01:59 UTC SKM (Stephen) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: kathy mortensen Subject: I give up, maybe Date: Mon, 02 Feb 1998 23:41:47 -0700 Let's try the mexico event rolling through Pilot Hill Calif. at 3:08:24 UTC ^%$^%$#@ BI-FOCALS _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Dept. of Interior Router Failure Date: Tue, 03 Feb 1998 09:31:13 -0700 Having problems with connecting getting earthquake information? 2nd-hand news has it that the Department of Interior was upgrading their main internet router system when the company doing the switch ran into some problems, shutting the whole system down for the agency. The problem was so difficult that company had to call in another to solve the problem. The fiasco is going on its third day. Currently, much of the Department of Interior internet connection is down, including some parts of the USGS and NEIC. Should make for a good movie someday. -- ---/---- Charles P. Watson Seismo-Watch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Seismo Vault Ceiling Question Date: Tue, 03 Feb 1998 10:49:17 -0700 First off, a courtesy thank you to all who have shared in my previous questions, regarding temperature/humidity control in a crawl space seismo vault. It was most interesting, and will likely be of interest to alot of people with crawl space seismos. Insulation is basically a time delay measure of heat transfer. Heat has a tendency to rise. When I come to the "ceiling" of my crawl space vault, I am hesitating with questions of the amount of insulation necessary. Would it be better to have less insulation to allow any heat to be passively passed upward....or too have more insulation than the walls to stop any transfer? The room above the vault has the temperature maintained at a fairly consistent temperature year out, ...maybe ~ + - 15 degrees at the extremes. I have about 6" of common insulation at the present in the ceiling of the vault. I think a totally sealed walls & floor humidity & insulation control is better overall than a vented vault ....less rapid temp change. With heat having a tendency to rise... any suggestions or thoughts? Thanks in advance, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Dewayne and Linda Hill Subject: Utah Quakes Date: Tue, 03 Feb 1998 13:02:40 -0700 Does anyone have any ideas what is going on in Utah? At the location of 38.0n, 112.6w there have been 32 quakes in the last 4 days. Could all of these be aftershocks from the 4.0 on 1/30/98? -- Dewayne (n0ssy) & Linda (n0uqf) Hill Westminster, Colorado USA 39.83569n 105.06270w. Elev 5660ft. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: ufkartfm Subject: injection waves - quake dx - explosive sound - etc. Date: Tue, 3 Feb 1998 12:23:23 -0800 (PST) -----BEGIN PGP SIGNED MESSAGE----- greeting folks, I. station construction report 1. completed a. seismic monitor shack with a 4x4' concrete slab b. purchased a pc for a/d to use in place of my dec machines 2. waiting for winter to end and learning 'lots from you'. II. injection waves (???) 1. a few weeks ago my other half yelled from the tv room "get in here, you may want to watch this". by the time i arrived the piece was almost over and was on geothermal injection. they were showing some form of a wave that was produced during the injection process. this was all i got. 2. we live in the area known on the quake maps as "The Geysers". 3. can anyone tell me if these waves will have an effect on my station, once it is constructed? III. quake dx (???) 1. since i live in a highly active seismic area, my interest is in distant quakes or (smile) quake dx. 2. i have read all of the archives and understand (smile - to some degree) what i have to do to get what i want..... but, 3. i would like hear from someone else in a highly active area who may have the same interest, and what they did to achieve it. IV. explosive sound (???) 1. 1/27/98 17:43:26 38.80N 122.73W Ml 3.2 03.8km 7km E of the Geysers 2. i was sitting at my workstation when this occurred and heard it coming (a rumbling sound which i have experienced before) from the north. 3. for lack of better words, at the 'point of impact' (or when the house shook and my machines jumped up and down) there was a VERY LOUD explosion, the likes of which, i have never heard before (in 34 years of living in california). 4. i called my neighbor (retired sheriff who has lived here longer than i have) and asked if they had ever heard something like this before and was told "only 4 or 5 times". 5. can someone explain what this explosive sound was about or why it happened? tia, - -- curtis - ufkartfm@........... - site administrator for Nobody I want Nobody to control my life! How about YOU? http://www.netvideo.com/nobody -----BEGIN PGP SIGNATURE----- Version: 2.6.3a Charset: noconv iQCVAwUBNNd8w+Dq6PoqA7oZAQHrFgP+LT6eXkYpAuEUKn2FCEhQZ5/moOiPBHwm vpv8OIXpzgNxpRzKbgAHonosCyDheJFHq2njh2DdVWVCU/GDoPnwTwPBDj4fBVmZ lKB079UHuud2wSO6JnZBe7bYRpqYtm7Bm/7fiWQXs3esr52TBYd/A8TnP2LjxtF1 ea5cr35VRl4= =83rj -----END PGP SIGNATURE----- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Damping using thin laminations Date: Tue, 03 Feb 1998 20:50:12 +0000 meredith lamb wrote: > > > Your projected 1/4" thick damping plate which is mounted > across the horizontal magnets as one piece.....what if?....... > there were a number of vertical bars of copper placed in front > of all six magnets? Say....~/2" width X 1/4" thick X ~ 6" long. > Would the effective damping show an increase....or would it make > any difference...versus...one big plate of copper? ............. Hi all, Although I use solid copper for damping, it occurs to me that transformer cores are laminated. I wonder if many THIN copper strips, (with insulation between), would offer more damping, for a given amount of copper?? Too much damping tho' is to be avoided. Has anyone tried this out ?? Regards, Albert Noble (England) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: Damping using thin laminations Date: Tue, 3 Feb 1998 14:59:51 -0600 Albert, Transformers are laminated for exactly the opposite reason. The laminations reduce the eddy currents in the iron which cause losses. For damping you want the maximum amount of "loss" to absorb the energy from the motion of the thing you are damping. Probably the best thing to use would be a big chunk of pure silver.:) Jim Hannon prewar@.............. on 02/03/98 02:50:12 PM Please respond to psn-l@............. To: psn-l@.............. cc: (bcc: James M Hannon/CedarRapids/Collins/Rockwell) Subject: Damping using thin laminations Hi all, Although I use solid copper for damping, it occurs to me that transformer cores are laminated. I wonder if many THIN copper strips, (with insulation between), would offer more damping, for a given amount of copper?? Too much damping tho' is to be avoided. Has anyone tried this out ?? Regards, Albert Noble (England) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: Damping using thin laminations Date: Tue, 3 Feb 1998 20:47:19 -0600 (CST) THin plates provide MORE resistance; for damping we want minimal resistance to the induced eddy currents, so the maximum induced current produces the strongest opposing magnetic field. As you observe, transformers are laminated to minimize currents flowing in the core that only produce heat. You can experiment with the damping effect by proping up your copper or aluminum plate at an angle and letting the magnet slide down. The little rare-earth magnets from RS take about 2 seconds to slide 6" on a 1/4" Al bar, but go almost twice as fast on 1/16" material. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Warner Lindholm Subject: Re: Questions About STM-8 Boom Date: Tue, 3 Feb 1998 21:13:40 -0800 (PST) Sean-Thomas, On Mon, 2 Feb 1998, S-T Morrissey wrote: >............. This is not technically "mass", as in F=m*a, > but the habit of calling a weight in a seismometer a "mass" > dates to 1909. So the inconsistency is consistent. > You've been awfully patient Sean-Thomas so here's another question: If the "mass" term in the transfer function is really weight then one would think g, the acceleration due to gravity, would show up in the transfer function somewhere . Where's it hidden? In your Dec 22 response to the list some terms were defined. Under b: it says, "In the transfer function, "G" is actually conventional "G"/M. G=Gn/M (m/sec**2/amp " It seems to me that as it stands the dimensions are 1/amps. Could you clarify this please? I don't understand the statement. Evidently in the transfer function G is the term that represents the amount of acceleration given to the mass by the current in the voice coil. If I plug in 0.5 I'll get the wrong result won't I? BTW, how'd you like Adak? I was there once but the Navy wouldn't let us out of the terminal so I didn't see much. We used to get the P-3 Orions into Cold Bay for fuel alot. I lived in Dutch Harbor/Unalaska and Cold Bay for nine years. I've been back in the lower-48 for almost ten years now and I still dream about the Aleutians about twice a week. Thanks, -Warner _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Bob Lewis Subject: Road Trip Date: Wed, 4 Feb 1998 08:19:49 -0800 I'll be leaving today for Mountainview, California...which is between San Jose and Redwood City. One of our Raytheon subsidiaries there needs some help, so Bob the Intrepid Troubleshooter gets to go help! I'm of course planning to visit Larry while I'm there, and I would really like the opportunity to meet and visit with any of you that are in the area. I will be there for 2-4 weeks. I'd love helping any of you with whatever projects that you might need some help with. That would sure beat watching TV from the motel! I'll have my laptop with me; my on-the-road e-mail address is: relj@.......... (Note that this is different from the address shown in the stations list) From: prewar Subject: Re: Damping using thin laminations Date: Wed, 04 Feb 1998 14:36:27 +0000 Hi Sean, Jim, and All, Point taken re laminations.....What if, as everyone is using loudspeaker magnets and the voice coils, these days, how about replacing voice coil with a SOLID copper ring and use magnet and ring for damping ?.... Or, easier still, just 'short out' coil windings !!...??? Any old speaker could be used, so cheaper than purchasing expensive copper (or silver! ). Regards, Albert Noble (England). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: Damping using thin laminations Date: Wed, 04 Feb 1998 08:22:44 -0800 Albert -- Connecting a resistance across a voice coil has worked well for me. You can adjust the resistance to vary the amount of damping -- with resistances down to zero and below, using the "Negative Impedance Converter" discussed here a few weeks ago. As a limit, you can achieve almost infinite damping by connecting a negative resistance equal to the resistance of the coil across it. This is similar to having a superconducting ring inside the magnet. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: Damping using thin laminations Date: Wed, 4 Feb 1998 10:41:09 -0600 Karl and Albert, You may be missing the point of the thread here. The original discussion was how to damp out some parisitic vibrations of the support leaf spring in the STM-8. This is not the same as damping the instrument itself. In the STM-8 the instrument damping is performed by the feedback electronics via the voice coil. Jim Hannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: kathy mortensen Subject: Re: Road Trip Date: Wed, 04 Feb 1998 09:34:01 -0700 Bob Lewis wrote: > > I'll be leaving today for Mountainview, California...which is between San Jose > and Redwood City. One of our Raytheon subsidiaries there needs some help, so > Bob the Intrepid Troubleshooter gets to go help! I'm of course planning to > visit Larry while I'm there, and I would really like the opportunity to meet > and visit with any of you that are in the area. I will be there for 2-4 weeks. Hope you packed your water wings!!!! SKM Pilot Hill Calif _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: Damping using thin laminations Date: Wed, 04 Feb 1998 20:11:37 +0000 James M Hannon wrote: > You may be missing the point of the thread here. The original discussion > was how to damp out some parisitic vibrations of the support leaf spring in > the STM-8. This is not the same as damping the instrument itself. Hi, Yes, 'mis-threaded' on my part! Should have made it clear that I was referring to a straight forward hor. beam, and the damping of its natural period only, perhaps using a very old (and cheap!), loudspeaker for this. (perhaps with vary R across coil as Karl mentioned in his letter). I am using solid copper, (already purchased), but wondered if others, making 'simple hor.beams' , might save a bob or two, (8 or16 cents), by utilising any old redundant loudspeaker they may have in their junk boxes, or save having to use messy oil dampers. I am not referring to force feedback systems, just old fashioned hor.beams. Regards, Albert Noble (England) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: Damping using thin laminations Date: Wed, 04 Feb 1998 07:13:53 -0800 Albert Resistance across the coil is currently (no pun intended) working on my Lehman also. However I had some surplus magnets composed of parallel plates The magnets are very strong.I'm not sure what material they are. They look like stainless steel. The gap is about 5 mm. I found moving an aluminum plate parallel to the magnets developed a large damping force (eddy current). One can adjust the amount by how much the plate overlaps the magnet. There is less problem, for me ,positioning this assemble than a speaker coil/magnet assembly. prewar wrote: > > > Yes, 'mis-threaded' on my part! Should have made it clear that I was > referring to a straight forward hor. beam, and the damping of its natural > period only, perhaps using a very old (and cheap!), loudspeaker for this. > (perhaps with vary R across coil as Karl mentioned in his letter). > I am using solid copper, (already purchased), but wondered if others, > making 'simple hor.beams' , might save a bob or two, (8 or16 cents), > by utilising any old redundant loudspeaker they may have in their junk boxes, > or save having to use messy oil dampers. > I am not referring to force feedback systems, just old fashioned hor.beams. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Al Allworth" Subject: Re: Damping using thin laminations Date: Thu, 5 Feb 1998 00:24:17 -0800 Karl and PSN, I have been playing with the negative impedence converter off and on for several weeks now but haven't got much success as yet. I have built some wonderful oscillators at various frequencies but haven't found anything useful. I have used negative resistance devices before in Q multipliers and waveform shaping applications but never with a generator as reactive as a seismometer. I am trying to get it to work with a 1 Hz L-4. My understanding of a negative resistance is a device where the current goes down as the voltage increases. At rest the voltage and current are both zero. As the voltage rises from the seismometer, the current must be negative and flow from the + side of the opamp through the seismometer to Gnd. This appears to be happening but only seems ti increase the Q which looks like no damping at all. I can set the balance between the Negative feedback and the positive feedback to a point where it takes over a minute for the oscillation to die out. The resistor from the - input of the opamp and ground is equal to the resistance of the seismo. The resistor in the negative feedback is a pot so it can be adjusted so that the oscillation will die out. If the positive feedback is a little too much you can get a very nice sine wave at the natural frequency of the seismo. This might be handy if one wanted to match two seismos exactly by using a frequency counter. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: Utah Quakes Date: Thu, 05 Feb 1998 11:06:41 -0700 (MST) On Tue, 3 Feb 1998, Dewayne and Linda Hill wrote: > Does anyone have any ideas what is going on in Utah? > At the location of 38.0n, 112.6w there have been 32 quakes in the > last 4 days. > Could all of these be aftershocks from the 4.0 on 1/30/98? There does seem to be even a regional correlation, with the 3.9 that occurred in Winslow, AZ in January. Activity over a zone extending from Utah south into Arizona may be increasing, but I'll have to look at the smaller quake records to see if there is a south to north trend like it seems with the larger ones. It just shows us that this area is still seismically and volcanically active... ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ http://www.public.asu.edu/~hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Warner Lindholm Subject: Re: Questions About STM-8 Boom Date: Thu, 5 Feb 1998 14:39:47 -0800 (PST) On Tue, 3 Feb 1998, Warner Lindholm wrote: > Sean-Thomas, > > On Mon, 2 Feb 1998, S-T Morrissey wrote: > > >............. This is not technically "mass", as in F=m*a, > > but the habit of calling a weight in a seismometer a "mass" > > dates to 1909. So the inconsistency is consistent. > > > > You've been awfully patient Sean-Thomas so here's another question: If the > "mass" term in the transfer function is really weight then one would think > g, the acceleration due to gravity, would show up in the transfer function > somewhere . Where's it hidden? [snippage] > Thanks, > -Warner For those who might be interested in knowing the answer to the above question, (if they don't already consider it man-the-street-stuff) it can be found on page 13 of _Automatic Control Engineering_ by Francis Raven, 3rd ed. The explanation is simple: at equilibrium only two forces are acting, the effect of gravity on the mass and the spring restoring force. Because we're interested only in changes from equilibrium referred to an arbitrary reference, constant forces can be ignored. -Warner _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: Damping using thin laminations Date: Thu, 05 Feb 1998 16:05:39 -0800 Al -- I looked back at my notes on the NIC connection, and found an error in what I told you. I'm sorry for leading you astray. I had the two op-amp inputs reversed; otherwise the circuit is the same. When reversed, the seismo's coil should connect to the op-amp's inverting input and the Z impedance shown in the schematic should connect to the non-inverting input. Since R1 and R2 are about equal, which one is which doesn't matter very much. I'm not sure, but likely the circuit with the op-amp inputs reversed is not considered a NIC any more. It looks like a current-controlled voltage source, with positive currents producing a negative voltage. If you try it, let me know if it works. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: where is "g" Date: Thu, 5 Feb 1998 18:55:12 -0600 (CST) Warner and co; The gravitational constant "g" is in the force constant of the main coil, whose units are Newtons/Ampere. In calibrating the coil, a test weight of 1 gram is balanced by a current of 0.775 ma (as indicated by the VRDT). So Gn = (0.001 kg / 0.000775 Amp.)*9.806 m/sec^2 = 12.653 N/A. But the "G" in the transfer function is this Gn divided by the mass, so it has units of m/sec^2/amp. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Adak, Aleutians Date: Thu, 5 Feb 1998 19:23:46 -0600 (CST) Warner, I ran a 14 station telemetered seismic network plus a central observatory with a remote buried vault at ADAK from 1976 to 1993, when the funding ran out. I used to spend 6 to 8 weeks there in the "summer" (a way to beat the heat and humidity of St. Louis), and also made a mid-winter trip. From 1982 on we did not have helicopter support, so we went by fishing boat to the various islands, getting ashore by Zodiac, and hiking up to the stations with volunteers from the Navy base (the marines were the best: "we will carry you there if we have to, sir") to replace the 400 lb "air cell" battery pack that would run the station for the next TWO years. Every detail of the electronics was checked and "tuned up". It was no place to make mistakes, since we couldn't afford a repeat trip, since we could only get out in "decent" weather (seas less than 4 feet). The mug shot on the web page is from SE Kanaga island; it doesn't show the checklists I had taped inside my parka. I'll find some other photos to scan and post. Of course I have flown through Cold Bay many times on the way to Adak, unless Reeve Aleutian Air decided to go home (to Anchorage) via the AFB at Sheyma 400 miles to the west, and then fly a great circle back over the Yukon delta. We still have a VBB station there, with the STS-1 seismometers and low gain FBAs (force balance accelerometers) to record the BIG ones. The data are archived on tape, but can be retrieved by phone. regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Dewayne & Linda Hill Subject: Circuit modifications Date: Fri, 06 Feb 1998 02:44:09 +0000 If you build the Amp/Filter that is in the "http://www.info2000.net/~aloomis/seisfilt.htm" web page and you plan on using it with the Radio Shack A/D make the following changes to the Offset adjustment circuit. Replace the 100k ohm pot. with a 5k ohm pot. and add a 47k ohm resistor between the -12v supply and and the pot, then add another 47k ohm resistor between the +12v supply and the pot. This allows you to adjust the offset level with greater ease. Dewayne (n0ssy) & Linda (n0uqf) Hill Westminster, Colorado USA 39.83569n 105.06270w. Elev 5660ft. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Giovanni Rotta" Subject: from RESIA - ITALY Date: Fri, 6 Feb 1998 18:50:37 +0100 Hi, Friends !! I would like to built a new Lehman sensor. So, I need a detailed draw (measures in inch or centimeters) of Lehman sensor, if it is possible in jpg format. Thank you very much for your help ! Regards, Giovanni Giovanni Rotta rottag@.......... Via F. Pizzigoni, 10 33010 Resia (Udine) Italy Lat. 46.22N Long. 13.18E _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Dick Webb Subject: Arrival Times Date: Fri, 06 Feb 1998 21:13:17 -0500 I seem to recall that there was a site that enabled one to enter the epicenter and station location and provided the arrival times of the various phases. I believe it used various catalogs for source data. Does it still exist and if it does what is it's address. Another question, considering all the arrival time information in the data being sent to Larry via his Winquake files, has anyone considered using it to calculate epicenter information in real, or near real time? I bet we can send in the data pretty darn fast. Wonder if we could beat some of the professionals with an epicenter determination. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Francesco Subject: MEDIUM QUAKE IN CENTRAL ITALY Date: Sat, 07 Feb 1998 03:39:55 +0100 Hi to all, All Italian station had registered a medium quake occurred at 0.59 UTC on Central Italy. There is still a large afterschock. FRANCESCO NUCERA OSIMO - Ancona - ITALY Lat. 43 29" E - Long. 13 29" E --------------------------------- "The natural catastrophes serve to adjust the the clock's hands of the civilization" Haroun Tazieff. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: peaches@............ (Donna Whitaker) Subject: Re: Arrival Times Date: Fri, 6 Feb 1998 17:25:27 -1000 (HST) Hi Dick. Try> http://www.giseis.alaska.edu/Input/lahr/artim.html Tony >I seem to recall that there was a site that enabled one to enter the >epicenter and station location and provided the arrival times of the >various phases. I believe it used various catalogs for source data. Does >it still exist and if it does what is it's address. > >Another question, considering all the arrival time information in the data >being sent to Larry via his Winquake files, has anyone considered using it >to calculate epicenter information in real, or near real time? I bet we >can send in the data pretty darn fast. Wonder if we could beat some of the >professionals with an epicenter determination. > >_____________________________________________________________________ > >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: Clark Wockner Subject: Re: Arrival Times Date: Fri, 06 Feb 1998 21:27:26 -0800 Dick Webb wrote: HI Dick: Try this http://www.giseis.alaska.edu/Input/lahr/artim.html Clark > > I seem to recall that there was a site that enabled one to enter the > epicenter and station location and provided the arrival times of the > various phases. I believe it used various catalogs for source data. Does > it still exist and if it does what is it's address. > > Another question, considering all the arrival time information in the data > being sent to Larry via his Winquake files, has anyone considered using it > to calculate epicenter information in real, or near real time? I bet we > can send in the data pretty darn fast. Wonder if we could beat some of the > professionals with an epicenter determination. > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: Local W.Australia 2.0 event Date: Sat, 07 Feb 1998 15:48:28 -0700 Arie- It's good to see a local OZ event. I have never been to Western Australia, but I am going to visit my mother in Adelaide in April. -Edward > Local event with a P / S waves. > Is it correct etiquette to post such low level, local events? > It was the best of 5 events spread over 3 days. Arie. -- 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: Ted Blank Subject: Re: Arrival Times Date: Sat, 7 Feb 1998 23:44:40 -0800 (PST) I just tried this page, but for what I thought were reasonable entries for lat. and long., I got no results listed. Don't know if it was a problem with the server but is there any secret to using this page successfully? Looks like a great idea. Ted > > Dick Webb wrote: > > HI Dick: Try this http://www.giseis.alaska.edu/Input/lahr/artim.html > > Clark > > > > I seem to recall that there was a site that enabled one to enter the > > epicenter and station location and provided the arrival times of the > > various phases. I believe it used various catalogs for source data. Does > > it still exist and if it does what is it's address. > > > > Another question, considering all the arrival time information in the data > > being sent to Larry via his Winquake files, has anyone considered using it > > to calculate epicenter information in real, or near real time? I bet we > > can send in the data pretty darn fast. Wonder if we could beat some of the > > professionals with an epicenter determination. > > > > _____________________________________________________________________ > > > > 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: Jim Bone Subject: Re: Arrival Times Date: Sun, 08 Feb 1998 00:00:18 -0800 Ted: I used 33.5, -117.6, and got apparently correct times using the southern California selection, but I'm not a scientist and have no way of checking the figures. From Mission Viejo, times seemed reasonable for recent Hemet, Yucaipa, and Ensenada events. Jim Bone Results: Quake parameters are from the command: finger quake@.................... Station Coordinates: 33.6500 -117.600 Maximum distance of interest (degrees): 20.0000 Minimum magnitude of interest: 2.50000 Compute travel times for P, Pdiff, PKP, PKiKP, S, Sdiff, SKS, SKiKS DATE-(UTC)-TIME LAT LON DEPTH MAG Q COMMENTS 98/02/03 16:45:34 34.11N 116.92W 9.5 3.5MLG A 9 mi. NE of YUCAIPA delta azimuth (degrees clockwise from north) (deg) eq-to-station station-to-eq 0.73 231.1 50.8 travel arrival time # code time(s) dy hr mn sec 1 Pg 14.06 0 16 45 48 2 Pb 14.81 0 16 45 48 3 Pn 16.40 0 16 45 50 4 Sg 24.27 0 16 45 58 5 Sb 25.58 0 16 45 59 6 Sn 28.40 0 16 46 2 7 PKiKP 992.97 0 17 2 6 DATE-(UTC)-TIME LAT LON DEPTH MAG Q COMMENTS 98/02/06 05:23:54 32.24N 116.39W 6.0 2.5MGN C* 29 mi. NNE of ENSENADA delta azimuth (degrees clockwise from north) (deg) eq-to-station station-to-eq 1.74 324.4 143.8 travel arrival time # code time(s) dy hr mn sec 1 Pn 30.67 0 5 24 24 2 Pb 32.26 0 5 24 26 3 Pg 33.27 0 5 24 27 4 Sn 54.01 0 5 24 48 5 Sb 55.82 0 5 24 49 6 Sg 57.43 0 5 24 51 7 PKiKP 993.60 0 5 40 27 DATE-(UTC)-TIME LAT LON DEPTH MAG Q COMMENTS 98/02/07 09:34:57 33.79N 116.98W 15.9 3.1MLG A 3 mi. NNW of HEMET delta azimuth (degrees clockwise from north) (deg) eq-to-station station-to-eq 0.54 255.1 74.7 travel arrival time # code time(s) dy hr mn sec 1 Pg 10.61 0 9 35 7 2 Pb 11.01 0 9 35 8 3 Sg 18.32 0 9 35 15 4 Sb 19.03 0 9 35 16 5 PKiKP 991.86 0 9 51 28 Ted Blank wrote: > I just tried this page, but for what I thought were reasonable entries > for lat. and long., I got no results listed. Don't know if it was a > problem with the server but is there any secret to using this page > successfully? Looks like a great idea. > > Ted > > > > Dick Webb wrote: > > > HI Dick: Try this http://www.giseis.alaska.edu/Input/lahr/artim.html > > -- Jim Bone jimbone@......... http://calproptax.com/ ------------------------------------------------------------ Author/Publisher of upcoming Property Tax - California Style see a sample at: http://calproptax.com/1proprty.html _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Dick Webb Subject: Re: Arrival Times Date: Sun, 08 Feb 1998 09:25:06 -0500 I checked my actual arrival times in Raleigh, NC against those supplied by the program and got suprisingly good agreement, ie. within seconds or less. I assume that any diferences I saw were a combination of my being able to pick accurately, the ray path and my site characteristics. I used the recent Chile and Oaxaca quakes. It's a great program for learning how to interpret seimograms. Dick >Ted: > >I used 33.5, -117.6, and got apparently correct times using the southern California >selection, but I'm not a scientist and have no way of checking the figures. From >Mission Viejo, times seemed reasonable for recent Hemet, Yucaipa, and Ensenada >events. > >Jim Bone > >Results: > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: STM-8 design change Date: Sun, 8 Feb 1998 12:21:26 -0600 (CST) TO those intereted in the STM-8 vertical seismometer: A new configuration of the hinge to leaf-spring geometry has solved the problem of constraining the upper end of the leaf spring. In previous configurations, the upper end of the spring applied an upward force to the underside of the boom, but the underside of the boom was aligned with the center of the hinges. If the upper end of the spring was constrained with flexures as at the bottom, the floating end, which was about 1/2 inch below the centerline of the hinges would move along the axis of the boom as the boom moved, rendering it unstable. So in the prototypes, a convex pressure restraint was used. This had serious problems, among which was that the pressure point could move and the spring was not constrained. Large vibrations (ie felt as when a Mac truck would rumble by) caused small (~0.2 micron) temporaty DC offsets in the mass position. In studying the dynamics of the geometry, it became clear that the point of application of the lifting force should be in line with the axis of the hinges. So I shortened the post that supports the hinges by 1 inch, and added a 1 inch spacer to the place the boom attaches to the hinges, so the boom height was not changed, Then I installed the same flexure arrangement as is used at the base of the spring. The mounting bracked for this is designed so that the center of the fixed rod is 1 inch from the mounting face, so now the force is applied AT the centerline of the hinges, and the upper end of the hinge, which is attached to the floating rod, is 1/2 inch above the centerline. This arrangement allowed some experiments with the mechanical period. I found that if the center of the upper restriant is 3 5/8" from the hinges and the lower end is 4 3/4" away, a period of 4 seconds results. But now the stiffness of the flexures of the leaf spring mount seems to be limiting further period lengthening; I cut the upper flexures down to 3/8" (from 3/4") wide, which helped. Longer flexures might also help, but this idea allows too much movement of the ends of the spring, which causes period instability. THe next plan is to use very fine braided stainless steel wire for the spring mounting flexures. (I have a roll of 0.010 Halibut fishing line, 500 lb test; it still may be too stiff) A longer period increases the Q factor, reducing the noise admittance of the sensor; 10 seconds would be nice. I am working on a drawing of all this; and will try to take new photos for the web site. The improvement has eliminated the non-linearity offsets from strong shaking. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: VRDT coils Date: Sun, 8 Feb 1998 13:18:35 -0600 (CST) Meredith, As with most of the design of the seismometer, there is room for some experimentation with the VRDT. The original constraint on its size was that an orthogonol pair had to fit inside the 1.5" ID housing of a biaxial tiltmeter casing, where a two pairs of VRDT coils sensed the position of a 1/2" diameter cylinder that was suspended as a 60 cm pendulum. (It did make a fine biaxial short-period horizontal sensor, but was difficult to damp passively). The real constraint in the relative dimensions is the consideration that the static reactance of a large inductor will be large compared with the change that is caused by the movement of the sensing vane. ie. A larger inductor (ie transformer) will have a larger fixed inductance. When used in commercial pressure sensors, the inductors are circular and about 1/2" in diameter. In liew of the TL019 transformers I found a supply of 500 ohm square centered coils at a surplus store; 10 of the TL019 laminates fit them exactly, and I have made many VRDTs with them. (THey are shown in the drawing of the VRDT assembly on the web page). With these 500 ohm coils, a change of 1 millihenry produces an output of 100 to 250 millivolts (equivalent to about 2 to 5 microns of movement of the vane), depending on the gain setting. The inductance of these coils is about 200 mhy when measured in the open; it is much higher when mounted in the VRDT. They produce the about same output as the TL019 coils in the same configuration. As for considerations of the gap between the coils, as it increases the sensitivity decreases markedly, as does the linearity. I have a test of one with a 3mm gap, and the sensitivity is only 13 mv/micron, and the linear range is only +,- 250 microns. Since we need to operate WITHIN the linear range, increasing the gap defeats our objective of a less critical adjustment, since we then have a working range of only +,- 0.25mm, as compared with +,- 0.5 mm with a 2mm gap. For reference, the operating range of the feedback of the prototypes is about +,- 10 microns, and the "capture" range is about 200 microns. As for the sensing vane: it is the center of the E laminate of a larger transformer. The laminates are made with a very high permeability soft iron: I have tried plain steel sheet, and get less than half the output. The laminate vane is mounted by soldering a 1/16" brass rod to one edge, which must be first filed clean of the black oxide. I saw a small 0.010" slit about 0.020 deep in one edge of the rod for a stronger attachment. The sensing vane must be significantly larger than the exposed poles of the inductor to minimize changes in the output caused by lateral or off-axis movement. In practice, it must be small enough that it doesn't touch the back of the mounting channel. But larger is also usually thicker, increasing the sensitivity, but limiting the working range. The vane and the coils must always be demagnetised after assembly; I use a RS tape-head demagnetizer. As for the number of laminates; I guess 19 is a typo; the transformers come with 14, and I checked several VRDTs here, and most have 15 or 16 crammed in. To clean them, I use copier dispersant as a solvent (someone ordered 2 cases of the stuff just as we changed brands of copier). BTW: I have corrected two of the drawings on the web site: THe VRDT oscillator options had the grounded pins numbers reversed, and the electronic block diagram now shows the high-pass filter between the VBB output and the line-driver amplifier that removes the DC voltage of the mass position from the drum recorder or the low dynamic range ADC. Regards, Sean-THomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Marnie Gannon Subject: Off topic humour Date: Sun, 08 Feb 1998 12:36:37 -0700 Now that Bill Gates has moved into his brand spanking new house in the Seattle suburbs, the following is a conversation overheard last week: Bill: "There are a few issues we need to discuss." Contractor: "Ah, you have our basic support option. Calls are free for the first 90 days and $75 a call thereafter. Okay?" Bill: "Uh, yeah... the first issue is the living room. We think its a little smaller than we anticipated." Contractor: "Yeah. Some compromises were made to have it out by the release date." Bill: "We won't be able to fit all our furniture in there." Contractor: "Well, you have two options. You can purchase a new, larger living room; or you can use Stacker." Bill: "Stacker?" Contractor: "Yeah, it allows you to fit twice as much furniture into the room. By stacking it, of course, you put the entertainment center on the couch... the chairs on the table... etc. You leave an empty spot, so when you want to use some furniture you can unstack what you need and then put it back when you're done." Bill: "Uh... I dunno... issue two. The second issue is the light fixtures. The bulbs we brought with us from our old home won't fit. The threads run the wrong way." Contractor: "Oh! That's easy. Those bulbs aren't plug and play. You'll have to upgrade to the new bulbs." Bill: "And the electrical outlets? The holes are round, not rectangular. How do I fix that?" Contractor: "Just uninstall and reinstall the electrical system." Bill: "You're kidding!?" Contractor: "Nope. Its the only way." Bill: " Well... I have one last problem. Sometimes, when I have guests over, someone will flush the toilet and it won't stop. The water pressure drops so low that the showers don't work." Contractor: "That's a resource leakage problem. One fixture fails to terminate and is hogging the resources preventing access from other fixtures." Bill: "And how do I fix that?" Contractor: "Well, after each flush, you all need to exit the house, turn off the water at the street, turn it back on, re-enter the house and then you'll be back on track." Bill: "That's the last straw. What kind of product are you selling me?" Contractor: "Hey, remember, if you don't like it, nobody made you buy it." Bill: "And when will this be fixed?" Contractor: "Oh, in your next house-which will be ready to release sometime near the end of 1998. Actually it was due out earlier this year, but we've had some delays..." [Note - making the rounds unattributed - ed.] _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Afghanistan quake Date: Sun, 08 Feb 1998 13:35:10 -0700 (MST) Hello Everyone, I was asked by a fellow student to find info on an Afghanistan quake that hit on 2/4/98. I found all the seismological info on the NEIC site but according to one report (Reuters I think) there were about 2,500 - 3,000 deaths in this event, however there were no other similar reports. If anyone has any more info on the aftermath of this quake I would appreciate it. ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ http://www.public.asu.edu/~hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: the official release fot the NZ event Date: Mon, 09 Feb 1998 09:15:53 +1200 hi all further to my post N/S and Vert g.phone files b4 here is the data from the Wellington Seismo. Obs. U.T.: 1998 February 8 1826 NZDT: 1998 February 9 7.26 a.m. Lat, Long: 45.06S 170.47E Location: 39 km west of Oamaru Preliminary Location. Focal depth: 12 km Magnitude: 5.3 Felt strongly in Oamaru. so u can now add ithe info to my event files Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Connectivity problems with my ISP. Date: Sun, 08 Feb 1998 16:03:16 -0800 Hi PSNers, I'm currently having connectivity problems with my ISP. The phone number that I dial into is dropping the line every 2 to 10 minutes. We are having a lot of rain, so I'm guessing that it has something to do with that. Until the problem gets fixed you will have problems with my web page at psn.quake.net and email sent to this list. Until the problem gets fixed please don't send mail to this list or send event files to event@.............. I will send out an email message when things get back to normal. Sorry for the inconvenience.... -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Seisguy@....... Subject: Fwd: 250 More Die in Afghanistan Tremors Date: Sun, 8 Feb 1998 21:40:27 EST >If anyone has any more info on the aftermath of this quake I would >appreciate it. Here you go John. Mike O'Bleness Northridge 250 Die in Afghanistan Tremors ..c The Associated Press By ZAHEERUDDIN ABDULLAH KABUL, Afghanistan (AP) - Snow, fog and civil war slowed relief workers struggling Sunday to reach quake-stricken northeast Afghanistan, where new tremors killed up to 250 people, according to the military alliance that controls the remote mountain region. Between 2,150 and 4,850 people are believed to have been killed in Wednesday's 6.1-magnitude earthquake and its aftershocks, and thousands left homeless by the tremors and landslides are suffering from subfreezing temperatures. ``Another quake hit Takhar province today, destroying three more villages,'' said Abdullah, a spokesman for the military alliance, said by satellite phone. Like many Afghans, he uses only one name. He said 250 people were killed and 50 injured in the latest tremor in the Rustaq district of Takhar province, 150 miles north of the Afghan capital, Kabul. Sunday's shaking caused more problems for international aid agencies, which have been scrambling to get emergency supplies to Rustaq, which is ringed by mountains and blanketed in snow. Local rescue teams ``are working very hard, but are desperate for outside help,'' said Sebgatullah Zaki, a representative of the military alliance in neighboring Pakistan. The first 6.1-magnitude quake destroyed more than 15,000 homes in the poor farming district, nestled at the junction of the Hindu Kush and Pamir mountain ranges, according to Afghan officials. Whole hillsides collapsed onto each other, crushing the mud and brick homes perched on the slopes, they said. Roofs heavy with snow collapsed on sleeping villagers, who had no chance to escape. There were more tremors late Saturday night and before dawn Sunday, which crumbled more villages. Abdullah said powerful jolts continued through the day. Masood Khalili, the Afghan ambassador to India, said soldiers had dug out 3,681 bodies by late Saturday. While Afghan officials have put the death toll as high as 4,850, including the new victims, the Red Cross is sticking with an estimate of 2,150, noting that the area was sparsely populated. Khalili said Wednesday's earthquake destroyed 11 large villages. In the worst- hit village, Ghunji, 600 homes were destroyed and 1,600 people were killed, he said. Physicians from Doctors Without Borders, the first foreign aid agency to reach the region, had treated hundreds by Saturday. A Red Cross plane packed with medical and water sanitation supplies landed Sunday in nearby Hajaghar. But the 24-mile road journey to the villages hardest-hit by the quake could take hours, since aftershocks have cracked roads to the region, said Juan Martinez, a spokesman for the Red Cross in Kabul. Red Cross officials in Pakistan said the four-person team will study conditions in the area and report back on further relief needs Monday. A U.N. team is to fly by helicopter from Dushanbe, the capital of neighboring Tajikistan, on Monday to survey the area. Military leaders who control northern Afghanistan have assembled 30 helicopters to help fly supplies into Rustaq, according to a spokesman, Zaki. Another Red Cross convoy passed safely Sunday through areas wracked by bitter fighting between the Taliban Islamic militia and its enemies, who control the northern 15 percent of Afghanistan, including Takhar. The convoy is expected to reach the quake victims Monday. Taliban supreme leader Mullah Omar announced a three-day cease-fire starting Saturday so opposition soldiers could assist in relief efforts. The Taliban controls the remaining 85 percent of Afghanistan, where it has imposed a strict version of Islamic law banning women from work and schools. Two U.N. convoys, which are approaching from the northeast and southwest carrying blankets, plastic sheeting and high-protein biscuits, also are expected to reach the area Monday. Another relief team, from the International Federation for the Red Cross and Red Crescent Societies, was still negotiating with guards at the Tajik border, 24 miles northwest of Rustaq, to cross into Afghanistan, according to officials in Geneva. AP-NY-02-08-98 1307EST Copyright 1997 The Associated Press. The information contained in the AP news report may not be published, broadcast, rewritten or otherwise distributed without prior written authority of The Associated Press. To edit your profile, go to keyword NewsProfiles. For all of today's news, go to keyword News. From: watson@................ (Charles Watson) Subject: Re: Afghanistan quake Date: Sun, 08 Feb 1998 21:26:14 -0700 John Hernlund wrote: > > Hello Everyone, > I was asked by a fellow student to find info on an Afghanistan quake > that hit on 2/4/98. I found all the seismological info on the NEIC site > but according to one report (Reuters I think) there were about 2,500 - > 3,000 deaths in this event, however there were no other similar reports. > If anyone has any more info on the aftermath of this quake I would > appreciate it. hey John, I found this URL with more info. The news is not good. You can use the search engine to get more info from other news reports. http://www.newsindex.com/ -- ---/---- Charles P. Watson Seismo-Watch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Fwd: 250 More Die in Afghanistan Tremors Date: Sun, 08 Feb 1998 21:29:35 -0700 Hey Seisguy, The news is not good from Afghanstan. Check out this URL: http://www.newsindex.com/ -- ---/---- Charles P. Watson Seismo-Watch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Mike Stickney Subject: Re: Arrival Times Date: Mon, 9 Feb 98 12:14:50 MST Ted: No results indicates that no quakes on the list met your search parameters. The default is magnitude 5.0 or greater quakes within 20 degrees of the location you entered (remember west longitudes are negative). To get arrival times for magnitude 5.0 or greater quakes anywhere on earth, change 20 to 180 degrees. Hope this helps. -Mike Stickney Montana Bureau of Mines and Geology Butte, MT ====================================== At 11:44 PM 2/7/98 -0800, you wrote: >I just tried this page, but for what I thought were reasonable entries >for lat. and long., I got no results listed. Don't know if it was a >problem with the server but is there any secret to using this page >successfully? Looks like a great idea. > >Ted > >> > Dick Webb wrote: > >> HI Dick: Try this http://www.giseis.alaska.edu/Input/lahr/artim.html _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: lahr@.................. Subject: Arrival Times Date: Mon, 9 Feb 1998 13:47:54 -0700 (MST) Hi Ted, Let me know if you continue to have any problems with the travel time calculator at: http://www.giseis.alaska.edu/Input/lahr/artim.html Be sure to use the correct sign convention for west and east, and as Mike suggests, you can adjust the distance and magnitude limits before making the search. There is also another page: http://www.giseis.alaska.edu/lahr/compute_tt.html that you can use if you already know the coordinates of the earthquake of interest. Yours, 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://www.aeic.alaska.edu/lahr http://www.lahr.org/john-jan _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Connectivity problems with my ISP. Date: Mon, 09 Feb 1998 19:35:06 -0800 Hi, It looks like everything is back to normal. My system has been connected to my ISP for over 4 hours without any line drops. You can start sending messages to the list again and event files to event@.............. -Larry >Hi PSNers, > >I'm currently having connectivity problems with my ISP. The phone number that I dial into is dropping the line every 2 to 10 minutes. We are having a lot of rain, so I'm guessing that it has something to do with that. Until the problem gets fixed you will have problems with my web page at psn.quake.net and email sent to this list. > >Until the problem gets fixed please don't send mail to this list or send event files to event@.............. I will send out an email message when things get back to normal. > >Sorry for the inconvenience.... > >-Larry Cochrane >Redwood City, PSN > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Practical site/xducer considerations Date: Tue, 10 Feb 1998 18:56:11 -0700 Anyone.... With the various xducer's around, and little mention found of site disturbances in past email logs....I was wondering if there is any prelimiary guidelines for an individual v/s their seis site? I've always used a coil & magnet configuration in the city. It would seem like there would be some limitations of gain obviously, and, being on clay, there is some seasonal swelling or tilt involved. Even though I'am engaged in vault rehab, I would imagine a "trade-off" would have to be considered even with a much tighter temperature control. So....if one starts with a coil & magnet seis, and wishes to upgrade to something else....would the sequence be say, a lvdt, then capacitance, then vrdt....and all of these considerations would be based on seis site.... If I lived on a desert with bedrock all around, I'd probably hit for the most sensitive xducer obviously. Point is....I don't know how successful others are with their xducers (outside of coil/magnet), and their environments...to begin realistic consideration....and not waste time & money. I realize certain seismo designs would be possibly more conducive than others....perhaps the S-G maybe much more stable than a Press-Ewing type......in the city.....or is it...all site location considerations? Guess I'am asking for opinions. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: Practical site/xducer considerations Date: Tue, 10 Feb 1998 20:42:04 -0600 (CST) Meredith, Almost all the transducers you mentioned have virtually unlimited resolution, at least down to the nanometer range. How they are used is where the trade-offs occur. The reason that coil-magnet types work so well is that they sense velocity, rather than displacement, which means that they don't see all the noises (tilt, thermal, hydration, loading, barometric buoyancy, etc) that plague "DC" sensors, which all the earlier optical-mechanical sensors were, and many force-balance systems are. Fortunately, with the VBB feedback, the primary output is the velocity signal, which can be high-pass filtered (at about 100 to 1000 seconds, depending on the site) to remove the DC noise: ie. the low-level mass position voltage (remember: the flat response to acceleration below To) that is also present and subject to the above noises. There is a good review of transducers in "Tiltmeters and Strainmeters" by D.C. Agnew of IGGP at SCRIPS (Reviews of Geophysics, Vol 24, No3, p579-624, Aug 1986) (I can put a copy in your SASE when I get the photos of the LP seis if you want). BTW: I just scanned the drawing of the leaf-spring mounting and the new configuration of the STM-8 to my web page of figures and drawings. Let me know if the presentation at two resolutions is helpful. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: STM-8 leaf spring drawing Date: Tue, 10 Feb 1998 22:12:39 -0600 (CST) Info re STM-8 seis: I just scanned the drawing of the leaf-spring mounting and the new configuration of the STM-8 to my web page of figures and drawings. Let me know if the presentation at two resolutions is helpful. I have also corrected the schematics of the VRDT oscillator and the electronics block diagram, the latter to show the 1000 second high pass output of the VBB to the line driver amplifier. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: STM-8 Hinge & Leaf Spring 2 size drawings Date: Tue, 10 Feb 1998 21:12:02 -0700 Sean-Thomas, Thanks for reply on prior msg Practical site/xducer considerations. Yes I'd definitely be interested in the "tiltmeters & Strainmeters article. Thanks. As you know I use a simple program called EZPHOTO version 2.5, made by Storm Technology Inc. This will capture a variety of photo & GIF drawings with no problem, in fact it often clearer than other programs. I downloaded both versions of your hinge & leaf spring drawing, but, the program made them both the same size on print out. Regardless, the detail was very good and there was no problem on any detail whatsoever with either size. I've yet to see any drawing it can't capture. Knock on wood. For those interested in trying out Ezphoto, they have a free older trial versions on the internet at: http://www.easyphoto.com/storm/ How well the older versions works, I don't know, my version came with the computer. Super simple program for the purpose. Thanks for the considerable effort to get it on your web site, this drawing answers all my questions on the detail principallly involved with the spring leaf flexures. Very interesting to say the least. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: EZphoto addenium to S-T drawings 2 size drawings Date: Tue, 10 Feb 1998 22:44:55 -0700 Always forget something.....the ezphoto program will print out any and all of Sean-Thomas GIF drawings on ONE page, regardless of size. The most important fact besides clarity, I would forget to mention. > As you know I use a simple program called EZPHOTO version > 2.5, made by Storm Technology Inc. This will capture a variety > of photo & GIF drawings with no problem, in fact it often clearer > than other programs. I downloaded both versions of your hinge & > leaf spring drawing, but, the program made them both the same > size on print out. Regardless, the detail was very good and > there was no problem on any detail whatsoever with either size. > I've yet to see any drawing it can't capture. Knock on wood. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ted Blank Subject: Re: Arrival Times Date: Wed, 11 Feb 1998 07:33:45 -0800 (PST) Thanks to everyone who explained things, I have it working now. Boy is that going to be useful. Regards, Ted > > Hi Ted, > > Let me know if you continue to have any problems with the > travel time calculator at: > http://www.giseis.alaska.edu/Input/lahr/artim.html > > Be sure to use the correct sign convention for west and > east, and as Mike suggests, you can adjust the distance and > magnitude limits before making the search. > > There is also another page: > http://www.giseis.alaska.edu/lahr/compute_tt.html > that you can use if you already know the coordinates > of the earthquake of interest. > > Yours, > 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://www.aeic.alaska.edu/lahr > http://www.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 > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Flexure/spring slits method on STM-8 seismometer? Date: Wed, 11 Feb 1998 19:54:10 -0700 Sean-Thomas, Curious about the method you use to create the slits in the square brass tube for the spring & flexures. This looks like the most difficult thing to machine. My guess is a Dremel like tool with either a small width saw or grinding head attached. Delicately mounted in a vise, and more delicately manuevered. Or..... mounted in a drill press with a compound moveable vise, with the saw on the spindle. Guessing of course. Or...hack saw the length for the spring and solder in afterward (but just for spring)? You probably knew I'd be asking. Also, ..could one use a 3/16" brass "U" channel, and a filler "L" channel for the main spring; and wedge the flexure between? Soldering thereafter. Not sure if there is such small variety of "U" or "L" available, but it sounds like an alternative. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: Flexure/spring slits method on STM-8 seismometer? Date: Wed, 11 Feb 1998 23:25:30 -0600 (CST) Meredith, I am not a very patient person, so I find dremmel tools to be under-powered and a waste of time. I make the slits with a coping or jewelers saw with an 0.010 blade for the flexures or a 0.015 blade for the leaf spring slot in the square tube; these are bought from the True-value store, as is the 3/16 ID square tube with 1/16 walls, etc. The square tube is cut the width of the spring at 3.5", and the blades are 5" long, long enough to make a broad flat cut that just clears the inside corner. The last bit is touchy because the vise is trying to close the cut. For the slits in the 3/16 rod, which must be used for rigidity, making a very shalow cut helps to get it straight, as does practice. I count on the 4-40 screws in holes tapped through the whole thing to hold it together; only the flexures are soldered in. Note that the fixed rods fit through 3/16 holes in the frame ends but are not secured, so as to be free to rotate for coarse adjustment of the spring-flexure- base geometry: however, they do not move in the normal range of motion of the spring or boom. Another detail is that the 6" long base for the 3/4" wide Ls for the flexure support is made from a 1"x 1" x1" U channel with 1/8 walls that has has the tops of the U sides cut off to 1/4" (with a fine carbide blade on the table saw: see how patient I am!: ps work with a longer length for safety) I hadn't considered the U channels, which I have seen but have very thin walls. they might work: the object is to secure the whole width of the leaf-spring ends to the floating bars. I hope this clarifies things. Regards, Sean-Thomas PS I tried to access the volcano-cam at Etna, but Italy wouldn't answer today. Maybe tomorrow....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Dewayne and Linda Hill Subject: EQ list Date: Thu, 12 Feb 1998 07:28:59 -0700 Can someone tell me where I can get just the text (without map) listing that is on the following web page "http://wwwneic.cr.usgs.gov/neis/bulletin/bulletin.html". Dewayne (n0ssy) & Linda (n0uqf) Hill Westminster, Colorado USA 39.83569n 105.06270w. Elev 5660ft. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: EQ list Date: Thu, 12 Feb 1998 07:26:31 -0700 Dewayne and Linda Hill wrote: > > Can someone tell me where I can get just the text (without map) > listing that is on the following web page > "http://wwwneic.cr.usgs.gov/neis/bulletin/bulletin.html". > There are several places to go for the finger listing of NEIC most recent events w/out their map links. Here is one of them: http://wwwneic.cr.usgs.gov/neis/finger/quake I have others on my Current Activity link from my home page. -- ---/---- 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: prewar Subject: DC sensors and coil/mag sensors Date: Thu, 12 Feb 1998 15:49:30 +0000 S-T Morrissey wrote: > .................................................... > Almost all the transducers you mentioned have virtually unlimited > resolution, at least down to the nanometer range. How they are > used is where the trade-offs occur. The reason that coil-magnet > types work so well is that they sense velocity, rather than > displacement, which means that they don't see all the noises > (tilt, thermal, hydration, loading, barometric buoyancy, etc) that > plague "DC" sensors.......................... Hi Sean and all, A minority of folk on PSN live in places far removed from the, 'Pacific Ring of Fire', so we don't get big traces. To augment my interest I have DELIBERATELY gone for a Hall Effect DC sensor on both my NS and EW beams. I use PC o/p to stop ALL beam drift giving me two sets of figures in the PC which seem just as interesting as 'quake data . These values show me how my concrete pier drifts day by day, which I am finding very interesting! The mag/coil sensor would be 'transparent' to any of this interest. I seem to have the 'plague' you referred to above Regards Albert Noble (England). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: kathy mortensen Subject: Re: EQ list Date: Thu, 12 Feb 1998 08:50:06 -0700 Dewayne and Linda Hill wrote: > > Can someone tell me where I can get just the text (without map) > listing that is on the following web page > "http://wwwneic.cr.usgs.gov/neis/bulletin/bulletin.html". > > Dewayne (n0ssy) & Linda (n0uqf) Hill > Westminster, Colorado USA > 39.83569n 105.06270w. Elev 5660ft. When you do want to see were in the world the event happened, here is a site that has the neic list where the event names are a link to a map for that individual event. If it is in an area that you don't recognize just scroll down and zoom out. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: kathy mortensen Subject: Re: EQ list Date: Thu, 12 Feb 1998 09:07:00 -0700 kathy mortensen wrote: > > kathy mortensen wrote: > > > > Dewayne and Linda Hill wrote: > > > > > > Can someone tell me where I can get just the text (without map) > > > listing that is on the following web page > > > "http://wwwneic.cr.usgs.gov/neis/bulletin/bulletin.html". > > > > > > Dewayne (n0ssy) & Linda (n0uqf) Hill > > > Westminster, Colorado USA > > > 39.83569n 105.06270w. Elev 5660ft. > > > > When you do want to see were in the world the event happened, here is a > > site that has the neic list where the event names are a link to a map > > for that individual event. If it is in an area that you don't recognize > > just scroll down and zoom out. I always have to forget something!!!!!! http://civeng.carleton.ca/cgi-bin2/guakes/ SKM (Stephen) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: lahr@.................. Subject: Smithsonian Volcano listserver Date: Thu, 12 Feb 1998 10:20:08 -0700 (MST) This is an excerpt from the most recent message from the Smithsonian Volcano listserver. If interested, subscription instructions are located at http://www.volcano.si.edu/gvp/gvn/volclist/index.htm This site also includes an archive of the list contents. 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://www.aeic.alaska.edu/lahr http://www.lahr.org/john-jan > From owner-volcano@.................. Wed Feb 11 16:59 MST 1998 > Date: Wed, 11 Feb 1998 13:08:19 -0700 (MST) > From: Global Volcanism Network > Subject: GVN Bulletin v. 22, No. 12, December 1997; part 2 of 2 > X-Sender: "Global Volcanism Network" > To: VOLCANO@.................. > Mime-Version: 1.0 > Resent-Subject: GVN Bulletin v. 22, No. 12, December 1997; part 2 of 2 > Approved-By: Jon Fink > > Smithsonian Institution > Bulletin of the Global Volcanism Network > Volume 22, Number 12, December 1997 (part 2 of 2) > > > Long Valley > California, USA > 37.70 N, 118.87 W; summit elev. 3,390 m > > The following summarizes USGS quarterly Long Valley Caldera > Monitoring Reports from January-June 1997. Activity during 1996 > was summarized in Bulletin v. 22, no. 11. During December 1997 an > episode of increased deformation occurred at Long Valley; > information on this event will be included in a future Bulletin. > > Seismicity. Earthquake activity within the caldera remained low > during the first three months of 1997; activity included > occasional small (M <3) events in the S half of the caldera but > no swarms. A M 2.9 event on 22 February at the resurgent dome's > SE margin was the largest during January-March 1997. > > Outside the caldera, two M 4 earthquakes S of Convict Lake (4 km > S of the caldera) attracted considerable media attention due to > their timing with respect to the release of disaster movies > featuring erupting volcanoes. The first, a M 4.2 earthquake on 10 > February, occurred three days after the opening of "Dante's > Peak," a movie depicting a destructive eruption in the Cascade > Range. The second, a M 4.1 earthquake on 24 February, occurred > the day after the television movie "Volcano: Fire on the > Mountain" aired about a fictitious volcano at a ski resort in > California. The level of earthquake activity in the Convict Lake > vicinity showed a modest increase after 10 February but gradually > slowed through mid-March. All events were M <3 except for three > aftershocks of the 22 February earthquake. > > Although the frequency of small earthquakes increased in early > May, seismicity remained low during April-June. On 1 April, a > cluster of earthquakes near Laurel Springs along the caldera's S > margin (8 km ESE of Mammoth Lakes) included M 2.7 and 3.3 events. > The largest event within the caldera during April-June was M 2.9 > on 5 May inside the S margin ~2 km NE of Convict Lake. A small > cluster of earthquakes including M 2.5 and 2.6 events occurred E > of the geothermal plant in the S section of the dome on 13-14 > May. Low-level seismicity beneath Mammoth Mountain included M 2.2 > and 2.0 events on 27 May. > > Deformation. Two-color geodimeter data indicated that extension > across the resurgent dome continued at a reduced rate during > January-June 1997 (~1 cm/year compared to 2 cm/year during much > of 1991 through mid-1996). The reduced deformation rate generally > coincided with the decrease in earthquake activity since mid- > 1996. Differential magnetometer data showed a similar slowing. > The most striking signal from continuous deformation instruments > (borehole dilatometers or tiltmeters) was a ~2 microstrain > compressional step on a dilatometer associated with massive > runoff and flooding after a 1-3 January storm. > > CO2 beneath Mammoth Mountain. During January-March 1997, > continuous CO2 monitoring sites in the Horseshoe Lake tree-kill > area reflected the annual buildup in soil gas due to the > blanketing effect of snow. During April-June, no new observations > were made. > > Regional activity. The only M 3 earthquake in the Sierra Nevada > block (other than on 10 and 24 February) during January-March was > a M 3.3 event beneath Red Slate Mountain (17 km SSE of Mammoth > Lakes) on 18 March. Minor earthquake activity near Tungson Hill > (10 km W of Bishop) included a M 3.0 event on 11 March and a M > 3.2 event on 25 March. During April-June, the Sierra Nevada block > produced occasional M ~3 and smaller earthquakes. A cluster of > earthquakes on 10-12 April included two M 3 events beneath Laurel > Canyon (~8 km SE of Mammoth Lakes). On 25 May, a M 3.3 earthquake > occurred beneath the N flank of Red Slate Mountain. On 26 June, a > M 3.0 event occurred near Rock Creek Lake (24 km SE of Mammoth > Lakes). > > Notification and response terminology. Because the system of > public notification of activity used at Long Valley since 1991 > was often misinterpreted, new terminology to describe conditions > was adopted on 12 June 1997. The old system assigned letters to > the levels of volcanic unrest; however, the alphabetic terms were > not meaningful to the public and were often reported as "alerts" > or "watches" that overstated the level of unrest. The new > terminology uses color codes and more descriptive phrases. In > this system, condition green indicates no immediate threat and > typical behavior; condition yellow indicates a watch due to > intense unrest, for example earthquake swarms including events of > M 5 or greater; condition orange indicates that an eruption is > likely and evidence of magma movement at shallow depth; and > condition red indicates an eruption underway. > > The 17 x 32 km Long Valley caldera lies E of the central Sierra > Nevada, ~320 km E of San Francisco. The caldera formed ~760,000 > years ago as a result of the Bishop Tuff eruption. Resurgent > doming was followed by eruptions of rhyolite from the caldera > moat and rhyodacite from the outer ring-fracture vents until > ~50,000 years ago. Since then the caldera has remained thermally > active, and in recent years has undergone significant > deformation. Since 1980, typical behavior at Long Valley has > included as a many as 10-20 earthquakes/day of M <2, occasional > small to moderate earthquake swarms, and steady uplift of the > resurgent dome at a rate of ~2-3 cm/year. Although distinct from > Long Valley Caldera, the N-S trending Inyo Craters volcanic chain > partially extends into the caldera. > > Reference: Hill, David P., 1997, Long Valley Caldera Monitoring > Report (January-March and April-June 1997): U.S. Geological > Survey, Volcano Hazards Program. > > Information Contact: David Hill, U.S. Geological Survey, MS 977, > 345 Middlefield Rd., Menlo Park, CA 94025 USA (Email: > hill@.................... URL: > http://quake.wr.usgs.gov/VOLCANOES/LongValley/index.html). > > > > > EARTHQUAKES > > Table 3 lists December earthquakes that were either large (M >= > 6.5) or damaging or both. On 5 December a Mw 7.9 event struck > near the E coast of Kamchatka approximately 300 km SW of > Petropavlovsk-Kamchatskiy; this was followed later that day by a > Ms 6.5 event. The larger event was felt at Ust-Kamchatsk and > Severo-Kurilsk, Paramushir. In addition, it was reported as being > felt aboard a ship sailing from Chukotkato to the Maritime > territory. The epicenter was located ~90 km SE of Gamchen > volcano. > > Table 3. Summary of large and damaging earthquakes, December > 1997. Courtesy of the National Earthquake Information Center. > > DATE GMT MAG LAT LONG DEPTH REGION > 05 Dec 1126 Mw 7.9 54.87N 162.10E shallow E of Kamchatka > 05 Dec 1848 Ms 6.5 53.89N 161.51E shallow E of Kamchatka > 17 Dec 0438 Ms 6.5 51.31N 178.87E shallow Aleutian Islands > 22 Dec 0205 Mw 7.1 5.54S 147.93E 179 km Papua New Guinea > > On 17 December, a Ms 6.5 earthquake occurred in the central > Aleutian Islands ~10 km W of Amchitka Island (Rat Islands > region). The epicenter was located ~50 km S of Gareloi > stratovolcano. > > A Mw 7.1 (Ms 6.7) event shook eastern Papua New Guinea on 22 > December. The epicenter fell immediately N of the series of > straits between New Guinea and New Britain Islands at the S > margin of the Bismarck Sea. The spot lies ~125 km N of the city > of Lae and ~10 km N of Rooke Island's Umboi volcano. > > Information Contacts: National Earthquake Information Center > (NEIC), U.S. Geological Survey, MS 967, Denver Federal Center, > Box 25046, Denver CO 80225 USA; Steve Walter, U.S. Geological > Survey, 345 Middlefield Road, MS 977, Menlo Park, CA 94025 USA > (URL: http://quake.wr.usgs.gov). > > ##### > > This information is from a worldwide network of correspondents, > who receive a Bulletin that includes illustrations not available > in this electronic version of the text. Text, figures, and > photographs can also be accessed the Internet World Wide Web > (URL: http://www.volcano.si.edu/gvp/). The issue date is the > closing date for regular monthly reports, not the publication > date; more recent information about ongoing activity is often > included. > > * The Bulletin is available by subscription from the American > Geophysical Union, 2000 Florida Ave. NW, Washington, DC 20009 > USA, at $22/year for US addresses, $39/year outside the US. > > * The information in our reports is necessarily preliminary, and > subject to change as the reported events are studied in more > detail. Please contact the original sources for updates and > corrections before using Bulletin information. > > * The network depends on prompt communication from observers > around the world. Please help by sending news of current activity > via Internet electronic mail (gvn@................ telephone > (202:357-1511), fax (202:357-2476), or airletter (NHB MRC 129, > Smithsonian Institution, Washington, DC 20560 USA). > > ##### > > ___________________________________________________________________ > > Global Volcanism Network, NHB MRC 129 Tel: (202) 357-1511 > Smithsonian Institution Fax: (202) 357-3218 > Washington, DC 20560 Email: gvn@.............. > > URL: http://www.volcano.si.edu/gvp/ > ___________________________________________________________________ > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: kathy mortensen Subject: one more time Date: Thu, 12 Feb 1998 09:44:41 -0700 For those of you who haven't figured it out yet, I'll give you one last chance. If I don't get it right this time !!!!!!!!!!! For the NEIC with links to individual events, try: http://civeng.carleton.ca/cgi-bin2/quakes/ All I can say is there are people out there that are glad I'm not a brain surgeon!! SKM (Stephen) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: DC sensors and coil/mag sensors Date: Thu, 12 Feb 1998 12:52:26 -0600 (CST) Albert, Maybe "plague" is too strong a word. But for the last 40 years the WWNSS (worldwide network of standardized seismographs) operated by the USGS has employed two sets of velocity sensors, one at 1 second, and the other (the LP) at 15 seconds. This carefully avoids the microseism noise peak at 6 seconds, but couldn't take advantage of the earths low noise minimum at 100 seconds. However, most of the surface wave energy of teleseisms is at 20 seconds, which is why the Ms magnitude uses the peak amplitude of the 20 second waves. With the deployment of the global broadband network, we can now get data beyond 100 seconds, which is used in the moment-tensor magnitude determination. If you are recording a mass position output, you might want to string together a week or two of data and see if it is earth tides. I'm sure someone has a PC program to generate theoretical tides for comparison. The other parameter worth recording if you can is barometric pressure and temperature, both of which present a large signal in the mass position output. And another thought: if you aren't seeing teleseismic surface waves from major quakes, it may be a limitation of the dynamic range of your digitizer. I don't know what you are using. But with my 12-bit RS meter, if I recorded the full VBB output, the range would have to be +.- 10 volts, so the LSB would be 5 millivolts. But the storm microseisms are +,- 2 mv, and surface waves can seen at +,- 10 mv. So I use a single pole high pass filter (1000uf NP with 1 megohm) into the output amplifier to remove the mass position voltage, and operate the digitizer at a scale of 200mv, with the LSB being +,- 0.1 mv. Of course, if you have a 20+ bit digitizer, recording the full VBB output is no problem, and the data can later be sorted out with software as you suggest. The new global broadband stations use 24-bit ADCs. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: DC sensors and coil/mag sensors Date: Thu, 12 Feb 1998 12:52:26 -0600 (CST) Albert, Maybe "plague" is too strong a word. But for the last 40 years the WWNSS (worldwide network of standardized seismographs) operated by the USGS has employed two sets of velocity sensors, one at 1 second, and the other (the LP) at 15 seconds. This carefully avoids the microseism noise peak at 6 seconds, but couldn't take advantage of the earths low noise minimum at 100 seconds. However, most of the surface wave energy of teleseisms is at 20 seconds, which is why the Ms magnitude uses the peak amplitude of the 20 second waves. With the deployment of the global broadband network, we can now get data beyond 100 seconds, which is used in the moment-tensor magnitude determination. If you are recording a mass position output, you might want to string together a week or two of data and see if it is earth tides. I'm sure someone has a PC program to generate theoretical tides for comparison. The other parameter worth recording if you can is barometric pressure and temperature, both of which present a large signal in the mass position output. And another thought: if you aren't seeing teleseismic surface waves from major quakes, it may be a limitation of the dynamic range of your digitizer. I don't know what you are using. But with my 12-bit RS meter, if I recorded the full VBB output, the range would have to be +.- 10 volts, so the LSB would be 5 millivolts. But the storm microseisms are +,- 2 mv, and surface waves can seen at +,- 10 mv. So I use a single pole high pass filter (1000uf NP with 1 megohm) into the output amplifier to remove the mass position voltage, and operate the digitizer at a scale of 200mv, with the LSB being +,- 0.1 mv. Of course, if you have a 20+ bit digitizer, recording the full VBB output is no problem, and the data can later be sorted out with software as you suggest. The new global broadband stations use 24-bit ADCs. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Mount Etna Volcano cam in Italy Date: Thu, 12 Feb 1998 22:25:31 -0700 The internet address for the Mount Etna cam in Italy is: http://www.iiv.ct.cnr.it/files/cam_etna.html The volcano seems to be more active at this time. About 0000 hrs 02/13/98, it appeared to have been ocasionally spraying or a fountain action, along with lava flow down the flanks. As of 0500 hours it is continuing. At the time of this message it is night in Italy, so the view is only of the glowing lava. Daytime will come soon, and perhaps the view maybe more dramatic. Sunrise is about 0700-0730 GMT. The cam shot reloads every 30 seconds and is about 12K. For this reason you may need a relatively fast modem, before the next cam shot comes in, and if the ISP is slow, you may have to sporadically try at different times when the internet isn't so overloaded. For unknown reasons some observers have difficulty getting through. Don't know exactly why....but try both variations of the dash - or _ between "cam_etna" in the address above. Actually I view this site alot...but more than the view...it will continue receiving (as a rule), and I use this time to stay on line and do other things, especially for example, if I want to get out an email fast. Most ISP's have a time limit...mine is 20 minutes, before they shut you down as being "inactive". There is often clouds obscuring the cam view, so, try at various times. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Arie Verveer Subject: SDR Network Date: Fri, 13 Feb 1998 19:57:53 +0800 Hi All, I'm having a little problem setting up my SDR logging computer over a network. I can get to two machines talking to each other in the windows 95 network environment. As per, L:arry's network instructions. When I shut down the SDR computer in the MS_DOS mode and use the "net" commands, the system gives this message. Message: 7361: IPX or NETBIOS must be running in order to load the network services. Your computer may be configured to use a monolithic driver, such as IPX or XNS and the driver is not loaded. To load driver, follow the instructions in the documentation that comes with your secondary network. I'm not very experienced in network connections and would appreciate any help or a BIG hammer! Regards Arie ajbv@............ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Arie Verveer Subject: apology Date: Fri, 13 Feb 1998 20:23:33 +0800 Hi Larry, Sorry about the typo in the your name. It should read "As per, Larry's ..." I need a good strong cup of coffee.... that will do it. A:rie ajbv@............ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: JIM_OBERHOFER@.......................... Subject: Re: SDR Network Date: Fri, 13 Feb 1998 10:30:29 -0800 Hi Arie, I'm a new user to this as well. The directions worked for me when I had TWO Windows'95 machines in place. To confirm the connection, you should be able to share a file from one machine to another in windows mode. you need to get this to work first. My situation was different... I was using a Win'95 machine as the logger with a Linux server. The file sharing worked with the '95 machine in Windows mode, but not in DOS mode. I ended up going back to DOS 6.2 and loading Lan Manager to get this to work with Linux. Win'95 in DOS mode apparently doesn't load all network drivers... only those needed to talk to another Win'95 machine... bummer. hope this helps. regards, jim ' kn6pe ______________________________ Reply Separator _________________________________ Subject: SDR Network Author: Non-HP-ajbv (ajbv@............. at hp-boise,mimegw7 Date: 2/13/98 3:57 AM Hi All, I'm having a little problem setting up my SDR logging computer over a network. I can get to two machines talking to each other in the windows 95 network environment. As per, L:arry's network instructions. When I shut down the SDR computer in the MS_DOS mode and use the "net" commands, the system gives this message. Message: 7361: IPX or NETBIOS must be running in order to load the network services. Your computer may be configured to use a monolithic driver, such as IPX or XNS and the driver is not loaded. To load driver, follow the instructions in the documentation that comes with your secondary network. I'm not very experienced in network connections and would appreciate any help or a BIG hammer! Regards Arie ajbv@............ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: DC sensors and coil/mag sensors Date: Fri, 13 Feb 1998 19:36:33 +0000 S-T Morrissey wrote: > ........If you are recording a mass position output, you might want to > string together a week or two of data and see if it is earth tides. > I'm sure someone has a PC program to generate theoretical tides > for comparison. The other parameter worth recording if you can is > barometric pressure and temperature, both of which present a large > signal in the mass position output.................... Hi Sean and everyone,Yes, I am developing software to show NS / EW hor. beam anti-drift o/p's from PC.....my seismic INPUT to PC is 16 bit A/D, but I use a 12 bit D/A from PC to control the position of each beam. It is this latter 12 bit info that is showing me how my pier tilts each day. I do indeed plan to show barchart/plot on PC on hourly/dayly/weekly basis to study ALL tilting influences. Local frost/rain/growing crops will no doubt also have influence! As beams are 30sec + periods the tilting is very pronounced of course....the MORE the merrier . We are 100 miles from coast, so tidal influence would be minimal would have thought. (unless the WHOLE of GB is tilting ). Incidentally, as I use PC in feedback loop to control beam drift, I am beginning to ponder on taking this all a step further soon, and try for a Computer controlled force feedback system!! After all, it's dead easy to change the incoming phase of seismic data thro' 90 degree etc. etc., and feed this info BACK to beams ! Just a dream at present tho' . Regards, Albert Noble (England) > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: earth tides Date: Fri, 13 Feb 1998 14:15:40 -0600 (CST) Albert, I was referring to the solid earth tides, which are different from ocean loading, and are caused by lunar/solar gravitaional deformation of the whole earth. At central lattitudes the horizontal tilt components average about 0.1 micro-radian peak to peak. There are programs that model them quite accurately when ocean loading is disregarded, So we use the earth tides to check the calibraton of tiltmeters after they are installed. Unfortunately, I don't have a PC version of them. They dominate the ULP or "mass-position" output of the very broadband sensors (the STS-1 at 360 seconds To) that we use. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: earth tides Date: Fri, 13 Feb 1998 14:15:40 -0600 (CST) Albert, I was referring to the solid earth tides, which are different from ocean loading, and are caused by lunar/solar gravitaional deformation of the whole earth. At central lattitudes the horizontal tilt components average about 0.1 micro-radian peak to peak. There are programs that model them quite accurately when ocean loading is disregarded, So we use the earth tides to check the calibraton of tiltmeters after they are installed. Unfortunately, I don't have a PC version of them. They dominate the ULP or "mass-position" output of the very broadband sensors (the STS-1 at 360 seconds To) that we use. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: DC sensors and coil/mag sensors Date: Fri, 13 Feb 1998 14:21:03 -0600 Albert, It is! The moon affects the land as well as the sea. Jim Hannon prewar@.............. on 02/13/98 01:36:33 PM Please respond to psn-l@............. To: psn-l@.............. cc: (bcc: James M Hannon/CedarRapids/Collins/Rockwell) Subject: Re: DC sensors and coil/mag sensors We are 100 miles from coast, so tidal influence would be minimal would have thought. (unless the WHOLE of GB is tilting ). Regards, Albert Noble (England) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: long period stuff Date: Sat, 14 Feb 1998 15:59:39 +1200 hi all, well i have finally got my commercial LP seismometer running it is a Press - Ewing ( Sprengnether) horizontal unit orientated NE/SW so hopefully will see the events to the north as well as to the east of me Nth is kermadecs, fiji etc, and east to Sth America some initial observations i can easily see the 6 sec seism. But there is also a pervasive 1.3 +- 0.2 sec oscillation which the geophones also see what is that does anyone know??? i presume there must be many natural seisms in the earth of different freqs. so far only one event recordedon the LP a ~M3.6 odd aftershock from ~90 km nth of me it performed well on this event. and of course for such a local event rich in hi freq signal the g.phones had much more amplitude. it is also interesting to see that the LP seismom. does not really respond to the man-made local noise eg vehicles, trains and such the LP seismom. is runninng through one of Larry C's pre-amp channels the g.phones are running through a pre-amp that does not have such heavy filtering. Cheers Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Marchal, Lare van" Subject: RE: long period stuff Date: Sat, 14 Feb 1998 06:44:16 -0500 Dave, You wrote: ' some initial observations i can easily see the 6 sec seism. But there is also a pervasive 1.3 +- 0.2 sec oscillation which the geophones also see' I live just a few miles from the coast. From time to time I see this oscillation on my geophones too. I think this is caused by the surf. = Regards, Marchal (The Netherlands)= _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: earth tides Date: Sat, 14 Feb 1998 12:05:46 +0000 S-T Morrissey wrote: > I was referring to the solid earth tides, which are different from > ocean loading, and are caused by lunar/solar gravitaional deformation > of the whole earth. At central lattitudes the horizontal tilt components > average about 0.1 micro-radian peak to peak..................... Hi Sean, Sorry, misunderstood you. In a very old book on seismography I have, reference is made to the moon's influence, and that is something I also wish to check out. At present I have only taken hourly MANUAL readings, but find that the EW seismo tilts east during day, and drops back west at dusk (sunsetting ??). Thanks for informqation re tilt values above. Would also like to take this oppurtunity of thanking you for all your work re web pages etc. and your many interesting letters on PSN on how to destroy all those stereo loudspeakers . Thanks. Regards, Albert Noble (England). > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: curtis Subject: Clock Synchronization - Unix/Linux/NT/etc. - NTP Date: Sat, 14 Feb 1998 10:10:25 -0800 (smile) since time is relevant, I am currently experimenting with xntp and felt it might be of interest to 'some' on this list. Keywords: Network Time Protocol, NTP, xntp, satellite, radio, modem home page: http://www.eecis.udel.edu/~ntp/ file location: ftp://ftp.udel.edu/pub/ntp/xntp.3-5.92.tar.gz Of interest to amatuer radio operators and shortwave listeners: (CHU (3330-7335-14670 kHz) shortwave interface) http://www.eecis.udel.edu/~ntp/database/html_xntp3.5f/gadget.html file location: ftp://ftp.udel.edu/pub/ntp/gadget.tar.Z -- curtis - pgp key by request - site administrator for Nobody I want Nobody to control my life! How about YOU? http://www.netvideo.com/nobody _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: shammon1@............. Subject: Re: Clock Synchronization - Unix/Linux/NT/etc. - NTP Date: Sat, 14 Feb 1998 10:28:40 -0800 Any suggestions on how to unpack these files on a DOS/Windows machine? Regards, Steve Hammond curtis wrote: > > (smile) since time is relevant, I am currently experimenting with xntp > and felt it might be of interest to 'some' on this list. > > Keywords: Network Time Protocol, NTP, xntp, satellite, radio, modem > > home page: http://www.eecis.udel.edu/~ntp/ > > file location: ftp://ftp.udel.edu/pub/ntp/xntp.3-5.92.tar.gz > > Of interest to amatuer radio operators and shortwave listeners: > (CHU (3330-7335-14670 kHz) shortwave interface) > > http://www.eecis.udel.edu/~ntp/database/html_xntp3.5f/gadget.html > > file location: ftp://ftp.udel.edu/pub/ntp/gadget.tar.Z > -- > curtis - pgp key by request - site administrator for Nobody > I want Nobody to control my life! How about YOU? > http://www.netvideo.com/nobody > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: apology Date: Sat, 14 Feb 1998 13:40:41 -0800 No problem... Any luck on getting our network stuff working? Unfortunately I never ran into the problem you are having, so I can't help.... -Larry At 08:23 PM 2/13/98 +0800, you wrote: >Hi Larry, > >Sorry about the typo in the your name. It should read "As per, Larry's ..." >I need a good strong cup of coffee.... that will do it. > >A:rie >ajbv@............ > > > > >_____________________________________________________________________ > >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: "Rex Klopfenstein Jr" Subject: Re: Clock Synchronization - Unix/Linux/NT/etc. - NTP Date: Sat, 14 Feb 1998 22:30:39 -0500 Yes, the new 32 bit version of pkzip will do the job! ---------- > Any suggestions on how to unpack these files on a DOS/Windows machine? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: Clock Synchronization - Unix/Linux/NT/etc. - NTP Date: Sat, 14 Feb 1998 22:21:41 -0800 Steve, You will need two programs. One is gunzip.exe. This will decompress the .z file. You will also need tar.exe to extract the files in the tar file. I will send you the ones I use. Both programs, and NTP, are 32bit so you will need Win95 or NT. -Larry Cochrane Redwood City PSN At 10:28 AM 2/14/98 -0800, you wrote: >Any suggestions on how to unpack these files on a DOS/Windows machine? >Regards, Steve Hammond > > >curtis wrote: >> >> (smile) since time is relevant, I am currently experimenting with xntp >> and felt it might be of interest to 'some' on this list. >> >> Keywords: Network Time Protocol, NTP, xntp, satellite, radio, modem >> >> home page: http://www.eecis.udel.edu/~ntp/ >> >> file location: ftp://ftp.udel.edu/pub/ntp/xntp.3-5.92.tar.gz >> >> Of interest to amatuer radio operators and shortwave listeners: >> (CHU (3330-7335-14670 kHz) shortwave interface) >> >> http://www.eecis.udel.edu/~ntp/database/html_xntp3.5f/gadget.html >> >> file location: ftp://ftp.udel.edu/pub/ntp/gadget.tar.Z >> -- >> curtis - pgp key by request - site administrator for Nobody >> I want Nobody to control my life! How about YOU? >> http://www.netvideo.com/nobody >> >> _____________________________________________________________________ >> >> Public Seismic Network Mailing List (PSN-L) >> >> 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: "Charles R. Patton" Subject: Re: Questions About STM-8 Boom Date: Sat, 14 Feb 1998 23:27:26 -0800 Sean-Thomas wrote: > The trade off is the Quality factor, which needs the product of the >period x the mass to be greater then 1. Dear Sean-Thomas, I seem to remember this statement in some previous posts (yours or somebody else's?), but in "Design of miniature wideband seismometers" by M.J.Usher and C.Gurlap in the Geophys. J.R. Astr.Soc (1978) 55, 605-613 the authors discuss the Brownian noise-equivalent requirements and have an equation: MoTQ ~=1 where Mo is mass, T is the period of the seismic sensor, and Q is the quality factor The important thing is that Q is also in the equation. I was wondering if you left it out because you are normally thinking of a critically damped seismic movement where the Q would be around 1, instead of a FFB arrangement which can take advantage of higher Q apparatus? I was first made aware of the need for high Q by a posting from Roger Baker in his posting to the PSN on Tue, 29 Apr 1997 18:16:03 -0500 (CDT) with a Subject: " Toward a jellybean seismometer." At the time I couldn't figure out the the exact reason for high Q though. Finally when I got a copy of the Usher/Gurlap article it became clear. The thermal Brownian movement can be viewed as an electrical equivalent noise input. They took the best seismometer siting locations, used the seismic noise floor of those sites to decide on a maximum noise equivalent for a good seismic instrument and set the MoTQ equation equal to it. It's just coincidence that the number happens to be 1. Charles R. Patton, Editor, Geo-Monitor _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Charlie Rond Subject: Re: long period stuff Date: Sun, 15 Feb 1998 01:49:54 -0600 Dave, > hi all, > well i have finally got my commercial LP seismometer running > > it is a Press - Ewing ( Sprengnether) horizontal unit orientated NE/SW > so hopefully will see the events to the north as well as to the east of me > > Nth is kermadecs, fiji etc, and east to Sth America Congratulations on the new seismometer! What do you mean - commercial?? You got something against these home-built monstrosities of ours? :-) Seriously, I'm glad for you, a bit envious, and looking forward to the seismograms from the new device. Charlie Rond -\/\--Public Seismic Network-Memphis rond@................ (901) 360-0302 [ free BBS ] http://gandlf.ceri.memphis.edu/~rond http://gandlf.ceri.memphis.edu/~rond/psn _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roger Baker Subject: Re: Questions About STM-8 Boom Date: Sun, 15 Feb 1998 04:23:07 -0600 Charles, et al, It is my impression that Brownian motion is a pretty much a theoretical limit without practical significance if a seismometer mass is on the order of a gram or more, although it may be a significant factor with tiny galvanometer mirrors. The real practical limit on building small seismometers seems to be air damping of the mass which reduces Q. Melton refers to this fact and suggests, as I recall, that masses should be 100 g or more for the best sensitivity for this reason. But nobody has tried to push seismic mass size downward to build smaller instruments without sacrificing sensitivity, by using a vacuum, so far as I know. Maybe Sean-Thomas knows. Of course fairly small masses can give good sensitivity in practice as geophones demonstrate for shorter period instruments. I came upon a reference the other day involving the Q of instruments based on guitar string type vibrations of various types of wire (surprise, steel music wire was best), and a vacuum can raise the Q by a factor of perhaps 5 or more. This should also apply to small seismographs and many small instruments with oscillating or vibrating elements. Tuning fork type suspensions, with two equal and opposite oscillators, are often used to reduce damping losses. To branch off onto a non-seismographic tangent, I believe that generally the most accurate approach to measuring physical parameters of vibrating mass oscillators having their oscillation sustained with feedback, is to use the least possible amplitude. And by the same token quartz crystal oscillators are probably least accurate when driven hard. You can sustain mechanical oscillation with a phase-locked loop. The most acccurate frequency measurement thus favors a very sensitive displacement sensor. I assume you could also use a helium atmosphere instead of a vacuum (and might it not be interesting to watch a fly try to take off in a helium/oxygen atmosphere). --Yours, Roger Baker _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: earth tides Date: Sun, 15 Feb 1998 10:50:19 -0800 Sean Thomas -- Curiosity... Is there a way to separate the effects of earth tilt due to Sun and Moon acceleration, from the direct effects of the accelertion on the seismometer? As I remember, the acceleration of the Sun and Moon are both in the range of a micro-g, which (if my estimates are correct) would cause an effect in the same magnitude ballpark as a 0.1 micro-radian tilt. Thinking about it, I suppose the timing of the effects could be a clue, since the direct acceleration on an E-W horizontal instrument would peak at rise and set of the body, and the tilt would likely peak at some other time. -- Karl At 02:15 PM 2/13/98 -0600, you wrote: >Albert, >I was referring to the solid earth tides, which are different from >ocean loading, and are caused by lunar/solar gravitaional deformation >of the whole earth. At central lattitudes the horizontal tilt components >average about 0.1 micro-radian peak to peak. There are programs that >model them quite accurately when ocean loading is disregarded, So we >use the earth tides to check the calibraton of tiltmeters after >they are installed. Unfortunately, I don't have a PC version of them. >They dominate the ULP or "mass-position" output of the very broadband >sensors (the STS-1 at 360 seconds To) that we use. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Walt Williams" Subject: Volcano cam in Italy & ISP TimeOut Date: Sun, 15 Feb 1998 11:23:36 +0000 Hello Meridith and all, Interesting volcano site. My ISP also times my connection and drops carrier. This practice is very annoying. I pay for unlimited access, sooo..., in Win95, I installed SYSTEM AGENT (from Win95 Plus Disk) and use it to periodically spawn PING.EXE, which I point at my ISPs domain URL. In the various dialog boxes of the SYSTEM AGENT scheduler, use these settings if you would care to try this counter-measure. Change Schedule Dialog: Run Hourly 59 Minutes after the hour Continue Running Advanced Options: Run program every 10 minutes Properties: CMD Line: c:\windows\ping.exe your.isp.domain Description: Ping my ISP - keep them honest Sincerely, Walt Williams dfheli@.............. ------------------ Edited Forwarded Message ------------------- ------- Forwarded Message Follows ------- Date: Thu, 12 Feb 1998 22:25:31 -0700 From: meredith lamb To: psn-l mailing list Subject: Mount Etna Volcano cam in Italy Reply-to: PSN-L Mailing List The internet address for the Mount Etna cam in Italy is: http://www.iiv.ct.cnr.it/files/cam_etna.html ------> Deletia <------ Actually I view this site alot...but more than the view...it will continue receiving (as a rule), and I use this time to stay on line and do other things, especially for example, if I want to get out an email fast. Most ISP's have a time limit...mine is 20 minutes, before they shut you down as being "inactive". There is often clouds obscuring the cam view, so, try at various times. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: earth tides Date: Sun, 15 Feb 1998 13:39:28 -0600 (CST) Karl, I'm trying to rummage up a PC version of the tidal harmonics program that calculates gravitaional, strain, and tilt components of the solid earth tides for any location for any epoch. I have an old fortran ver. and a C ver.;. I will post the PC ver. when I find it. You might recall the great fiasco of several years ago when I. Browning predicted a major quale at New Madrid based onthese programs.. Actually, the fall maxima were no larger than the previous spring, and fortunately all that happened was a lot of time and money was wasted., and the great flood was when everyone poured out their stale emergency water syupplies. o Regards, Sean-THomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: earth tides Date: Sun, 15 Feb 1998 13:09:44 -0700 (MST) On Sun, 15 Feb 1998, S-T Morrissey wrote: > You might recall the great fiasco of several years ago when I. Browning > predicted a major quale at New Madrid based onthese programs.. > Actually, the fall maxima were no larger than the previous spring, > and fortunately all that happened was a lot of time and money was > wasted., and the great flood was when everyone poured out their > stale emergency water syupplies. I remember this quite well; at the time I lived in the St. Louis area. At the time I was already hooked on the science of geology, but I think this event and the wild speculations drove my interest in seismology. The New Madrid fault zone is a very hot topic still (even with Browning deceased). I remember all the people buying earthquake survival kits, and the nervous school administrators in my area admitting that the schools' construction standards were not nearly up to par; which sprung a controversy in itself (they spent millions rewelding joints). ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ http://www.public.asu.edu/~hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: rayv Subject: RF Links for seismic monitoring Date: Sun, 15 Feb 1998 15:11:14 -0500 there is a good article in 73 Magazine October 1995 issue titled "boring beacons". It describes using a 4.5 hz geophone tied to a beacon transmitter. i have implemented the amplifier portion of the circuit and using a 4.5 hz geophone have seen a number of events. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: re Q Date: Sun, 15 Feb 1998 17:23:54 -0600 (CST) Charles, Roger, and co, Regarding the self noise of the mechanical system of a seismometer and Q: there seems to be no numerical definition of exactly what Q is: It is generally thought of as the inverse of the dissipative damping of the sensor, like the inverse of Bo (the air viscisity damping, usually due to the tight fit of the coil in the magnet). In an L4C seis, this is about 0.2; but I am not sure if this means that the Q is 5. For the sake of argument for VBB sensors, we generally assume that Q is at least 1, so we expect that M x Tn must be gt. 1. If the actual Q is in fact greater, so much the better. The exact number isn't really applicable in noise predictions, since mechanical micro-noises dominate. The largest VBB sensor I have configured is a WWNSS LP vertical (the Sprengnether 5000) with a mass of 11 kg and a Tn of 15 seconds, and a "Q" of 4, for a MTQ value of 660. It is, in fact a very low noise instrument, except for the ringing of the spring. I am operating it at a Tn of 600 seconds. Obviously, if the sensor is evacuated, Bo will vanish, and Q will go up. In some sensors the vertical is evacuated, but this is to remove barometric pressure admittance; it (or a strict pressure containment) will reduce such noise by as much as a factor of 10^3. Likewise, magnetic and eddy current damping (the common damping of moving coil sensors) will lower the Q and increase the noise, which is why it is not used in a VBB sensor. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: re Q Date: Sun, 15 Feb 1998 17:23:54 -0600 (CST) Charles, Roger, and co, Regarding the self noise of the mechanical system of a seismometer and Q: there seems to be no numerical definition of exactly what Q is: It is generally thought of as the inverse of the dissipative damping of the sensor, like the inverse of Bo (the air viscisity damping, usually due to the tight fit of the coil in the magnet). In an L4C seis, this is about 0.2; but I am not sure if this means that the Q is 5. For the sake of argument for VBB sensors, we generally assume that Q is at least 1, so we expect that M x Tn must be gt. 1. If the actual Q is in fact greater, so much the better. The exact number isn't really applicable in noise predictions, since mechanical micro-noises dominate. The largest VBB sensor I have configured is a WWNSS LP vertical (the Sprengnether 5000) with a mass of 11 kg and a Tn of 15 seconds, and a "Q" of 4, for a MTQ value of 660. It is, in fact a very low noise instrument, except for the ringing of the spring. I am operating it at a Tn of 600 seconds. Obviously, if the sensor is evacuated, Bo will vanish, and Q will go up. In some sensors the vertical is evacuated, but this is to remove barometric pressure admittance; it (or a strict pressure containment) will reduce such noise by as much as a factor of 10^3. Likewise, magnetic and eddy current damping (the common damping of moving coil sensors) will lower the Q and increase the noise, which is why it is not used in a VBB sensor. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen Caruso Subject: new madrid? Date: Sun, 15 Feb 1998 20:05:44 -0500 (EST) I saw today in the paper a 3.? in Missouri this past week sometime. Anybody catch this? Ohio just recently announced the placement of 6-8 seismographs statewide in a year or two time frame. STEPHEN CARUSO CET KB8UGH "Coincidence is a shortsighted mental delusion" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: new madrid? Date: Sun, 15 Feb 1998 23:25:58 -0600 (CST) A 3.0 last thursday 2/12/98 09:37:49 36.12N 89.71W; recorded by the St. Louis U. and the Memphis (CERI) networks. It also showed up well on the STM-8 (Beta) in my basement here, in spite of the heavy filtering (of street traffic) of frequencies above 3 hz. I am about 300 km from New Madrid. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Charlie Rond Subject: Re: new madrid? Date: Mon, 16 Feb 1998 00:26:47 -0600 >I saw today in the paper a 3.? in Missouri this past week sometime. >Anybody catch this? Ohio just recently announced the placement of 6-8 >seismographs statewide in a year or two time frame. Yes. See my 980212JA.RM1 2/12/98 posted to Larry Cochrane's Redwood City PSN site listed as "CARUTHERSVILLE, MO". Charlie Rond -\/\--Public Seismic Network-Memphis rond@................ (901) 360-0302 [ free BBS ] http://gandlf.ceri.memphis.edu/~rond http://gandlf.ceri.memphis.edu/~rond/psn _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Charlie Rond Subject: Re: new madrid? Date: Mon, 16 Feb 1998 00:32:21 -0600 Sean-Thomas, >A 3.0 last thursday 2/12/98 09:37:49 36.12N 89.71W; recorded by the >St. Louis U. and the Memphis (CERI) networks. >It also showed up well on the STM-8 (Beta) in my basement here, >in spite of the heavy filtering (of street traffic) of frequencies >above 3 hz. I am about 300 km from New Madrid. Did you post yours to Redwood City's PSN site? If not, I'd love to have a copy of it. Mine is posted as 980212a.RM1 (Caruthersville, MO) 2/12/98. Do you record in Cochrane's SDR format or Ted Blank's EMON format? Let me know if you'd like a copy of my seismogram. Keep up your good work... Charlie Rond -\/\--Public Seismic Network-Memphis rond@................ (901) 360-0302 [ free BBS ] http://gandlf.ceri.memphis.edu/~rond http://gandlf.ceri.memphis.edu/~rond/psn _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Al Allworth" Subject: Re: long period stuff Date: Sun, 15 Feb 1998 22:34:18 -0800 Hi Dave, I agree with Marchal. I live 1/2 mile from the beach and see this kind of stuff all the time. When the surf is high so is the signal. It is also modulated by another lower frequency, I'd guess to be around 8 or 10 second period. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Al Allworth" Subject: Re: re Q Date: Sun, 15 Feb 1998 23:09:34 -0800 -----Original Message----- From: S-T Morrissey Hi Sean-Thomas, I have been getting 2 of each of your posts lately. I thought you would like to know. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Arie Verveer Subject: SDR Network working Date: Mon, 16 Feb 1998 22:04:51 +0800 Hi All, Thanks for everyone's help, the final solution was to install the network adapter with a Windows 3.11 driver not the recommended Win95 driver. As soon as the win 3.11 driver was installed it worked. The logging over the network from Larry's SDR program works fine in MS_DOS mode. Arie ajbv@............ > When I shut down the SDR computer in the MS_DOS mode and use > the "net" commands, the system gives this message. > Message: > 7361: IPX or NETBIOS must be running in order to load the network services. > Your computer may be configured to use a monolithic driver, such as IPX or XNS > and the driver is not loaded. To load driver, follow the instructions in the > documentation that comes with your secondary network. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: new madrid? Date: Mon, 16 Feb 1998 15:07:19 -0600 (CST) Charlie Our data here was limited because the "wiggles" PC system was OTL, and so was the CGM system, so we had to rely on the analog monitors. At home, where the STM-8 is operating, my ADC is still the RS multimeter at 1 sample/second (good for near regional and teleseisms), and my monitor is the old Portacorder with FAX paper. Because of the local noise filters, it had an eP but a decent S/Lg. The telemetered experimental station CCMO in my back field had similar quality. The IRIS VBB staions all had good data, especially CCM. THey were used by the USGS. I am not concerned about sending my data to the PSN because it is rather redundant compared to the SLU/CERI database. However, I am interested in a VBB style ADC that samples at 20-50 sps for a short-period BHZ type channel with event detection but also provides a decimated/FIR-filtered stream at 1 sps for continuous LHZ data. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: earth tides Date: Mon, 16 Feb 1998 15:38:08 -0600 sean@........... on 02/15/98 01:39:28 PM Please respond to psn-l@............. To: psn-l@............. cc: (bcc: James M Hannon/CedarRapids/Collins/Rockwell) Subject: Re: earth tides Karl, I'm trying to rummage up a PC version of the tidal harmonics program that calculates gravitaional, strain, and tilt components of the solid earth tides for any location for any epoch. I have an old fortran ver. and a C ver.;. I will post the PC ver. when I find it. Regards, Sean-THomas _____________________________________________________________________ Sean, I seem to remember you saying you had a unix version of this program. If you have C source for the unix version I have had good luck porting this type of program to the PC. Could you post the unix version? Jim Hannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: [Fwd: Education and Outreach Updates] Date: Mon, 16 Feb 1998 16:06:49 -0700 -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". From: Kees Verbeek Subject: Re:BIG QUAKE Date: Tue, 17 Feb 1998 02:13:05 +0100 (CET) Hello all, Got a big quake coming in at this moment, someone got some news ? realy big!!!!!!!!!! Greetings Kees Verbeek Holland _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Francesco Subject: Re:BIG QUAKE Date: Tue, 17 Feb 1998 02:26:24 +0100 The italian stations had registered a very large phases started at 0.01.34 Utc Good P , S and great Lq LR I'm posting the file Preliminary location 11.400 km from Italy with Mg >7 !!! Sud America? FRANCESCO NUCERA OSIMO - Ancona - ITALY Lat. 43 29" E - Long. 13 29" E --------------------------------- "The natural catastrophes serve to adjust the the clock's hands of the civilization" Haroun Tazieff. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: North Atlantic Quake Date: Mon, 16 Feb 1998 19:33:14 -0600 (CST) 98/02/16 23:53:19 52.72N 33.61W 10.0km 6.6Ms North Atlantic Ocean (nice records here in St. Louis; probably really impressive in Holland) Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Francesco Subject: Big Quake on Atlantic Ocean Date: Tue, 17 Feb 1998 02:42:21 +0100 The right location of P and S say that the event is located 3500 c.a from Italy, Northern Atlantic Ocean Ms 6.8 The evaluation is confirmed by Neis FRANCESCO NUCERA OSIMO - Ancona - ITALY Lat. 43 29" E - Long. 13 29" E _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: ACole65464@....... Subject: Manual of Seismo. Observ. Practice Date: Mon, 16 Feb 1998 20:51:50 EST To the PSN, Some time back on a rainy day when I was surfing the Internet I came across a document that some of you may find a wee bit interesting, titled "Manual of Seismological Observatory Practice". I got my hands on an old photo copy of it some years ago (1979 was when it was originally printed) and I have been waiting since for a new release, the old edition is out of print. But now it (the 1979 ed.) is available electronically on IASPEI's web site: http://www2.seismo.com/seismo/msop/msop_intro.html Much of the info is outdated but as a lot of us are still basically using instrument designs from that era, it is still considered current. Sections titled "Instruments" and "Record Content" are still very helpful , and the section titled "Organization of Station Networks" describes the design basics of seismometer vaults etc. Plus there are many other informative sections. They are working on a new release of this document with many links back to the older one. This IASPEI web site could be linked from a web site visited frequently by amateur seismologists as it may answer several questions that we have at times when we want to know how the professionals do it. Happy reading, Allan Coleman _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: 1936 manual Date: Mon, 16 Feb 1998 20:14:07 -0600 (CST) Allan, Nice find; I'm lucky enough to have an original copy (my work here pre-dates it by ten years). An even more interesting document is the 1936 "Selection, Installation, and Operation of Seismographs" by H.E. McComb, USCGS publication 206 (cost 10 cents). It shows the transition from purely mechanical sensors to the early electromagnetic systems like the Galitzin, the Wenner, and the prototype of the Benioff. .... All the early narrow-band recorders.... Regards, Sean-Thomas. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: 1936 manual Date: Mon, 16 Feb 1998 20:14:07 -0600 (CST) Allan, Nice find; I'm lucky enough to have an original copy (my work here pre-dates it by ten years). An even more interesting document is the 1936 "Selection, Installation, and Operation of Seismographs" by H.E. McComb, USCGS publication 206 (cost 10 cents). It shows the transition from purely mechanical sensors to the early electromagnetic systems like the Galitzin, the Wenner, and the prototype of the Benioff. .... All the early narrow-band recorders.... Regards, Sean-Thomas. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: North Atlantic Quake Date: Mon, 16 Feb 1998 18:44:54 -0700 Looks like the quake struck the Gibbs Fracture Zone. Largest there since the M7.3 on 10/16/1974 -- ---/---- Charles P. Watson Seismo-Watch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: ACole65464@....... Subject: Re: 1936 manual Date: Mon, 16 Feb 1998 23:20:10 EST Sean-Thomas, The 1936 publication that you referred to I also happen to have a copy of. I found mine in a used book store here in Seattle for $1.50 about 3 years ago. I guess if you allow for inflation I got my copy at a similar price (?). Allan Coleman _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: duplication of mail Date: Mon, 16 Feb 1998 23:46:34 -0600 (CST) It seems that when I use R to reply to a mail originated with CAPITAL letters (PSN-L), the mailer deamon spawns a lower case address to psn-l, and then sends both. I realize that the duplication is a nuisance. Maybe the mailer can be educated. In the mean time, I will watch for the capital letters. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: STM Horizontal Date: Tue, 17 Feb 1998 00:13:34 -0600 (CST) Meredith, THe data from a horizontal is generally less interesting than the vertical, which shows the P wave very clearly. There is usually enough vertical energy in the shear wave also. H seises are very sensitive to tilt noise, which increases with the square of the operating period. I have presented two papers on efforts to reduce barometric-induced tilt noise in VBB horizontal data from the German instruments (abstracts are on the web site). Of course, verticals have the problem of mass buoyancy noise, which I am looking into resolving for the STM-8. The STM-8H is just a prototype, mainly to demonstrate the crossed hinge support that is entirely epoxied together. This design is preferred because the point of flexure of the hinges is exactly restrained, so the mass/coil movement is accurate. With the angled support wire, constraining the point of flexure is a design problem, and usually requires a transition from a long relatively rigid support to a very short flexible interval at the hinge point. Some configurations actually use a structural angled frame from the mass/boom up to the upper hinges, which are crossed flexures. I have had a 1kg weight resting on the end of the proto H boom here, and it hasn't gone anywhere. I plan to make a second vertical hinge with half the width of the bronze flexures; I don't anticipate any problems. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "REB" Subject: Date: Tue, 17 Feb 1998 13:11:20 +0000 I have being trying to leave this mailing list for days now, but I still keep getting loads. Can someone help me Rebecca Lloyd Fossil Fuels and Environmental Geochemistry NRG Drummond Building University of Newcastle 0411-319985 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: lahr@.................. Subject: Offshore activity Date: Tue, 17 Feb 1998 08:46:53 -0700 (MST) If you're interested in the offshore activity on the Juan de Fuca Ridge, check out this site for the 3D animation of the seismicity: http://newport.pmel.noaa.gov/axial98.html JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Martin Brewer" Subject: Re: Big Quake on Atlantic Ocean Date: Tue, 17 Feb 1998 20:55:30 -0400 Francesco, The North Atlantic 'quake was about the same distance from Bermuda as from you. I picked up good traces on both LP horizontals. Martin _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: STM-8 Beta Vertical Date: Wed, 18 Feb 1998 19:53:38 -0600 (CST) Re: new photos on STM's web site: I just scaned in the photos of the Beta vertical; they still are not as crisp as they could be; I need to use brighter lights. I have made them larger for better resolution. The details should now agree more with the drawings. Let me know if any needed details are missing. regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: new photos Date: Wed, 18 Feb 1998 21:53:39 -0600 (CST) Sorry for this repeat, but I forgot the url: Re: new photos on STM's web site: http://www.eas.slu.edu/People/STMorrissey/index.html I just scaned in the photos of the Beta vertical; they still are not as crisp as they could be; I need to use brighter lights. I have made them larger for better resolution. The details should now agree more with the drawings. Let me know if any needed details are missing. regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: STM Horizontal Date: Wed, 18 Feb 1998 10:15:15 -0800 Sean Thomas I have never observed the response of a vertical sensor to regional or teleseismic events (eg. never built one that was kept in operation for very long). Do the P,S and surface waves show up well?. I could see that the surface waves' would have reasonable vertical energy. Are there any other advantages to a vertical sensor besides the important ones you mentioned? Barry Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: vertical waveforms Date: Wed, 18 Feb 1998 23:42:24 -0600 (CST) Barry, The P-wave energy is predominantly vertical at teleseismic distances, and there is usually a strong vertical component of S, and LG is always strongly vertical. This is why anytime we have only one component, we prefer a vertical. In the case of the Aleutian network, we had a vertical and an EW horizontal, since the quakes were mostly south of the islands, and the horizontal polarization of S would be EW as the wave traveled north. You can look at the samples of data on my web site. The N. Atlantic event of Monday had a very energetic vertical surface wave. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: George Harris Subject: Re: vertical waveforms Date: Thu, 19 Feb 1998 09:10:48 +0000 S-T Morrissey wrote: > > Barry, > The P-wave energy is predominantly vertical at teleseismic > distances, and there is usually a strong vertical component > of S, and LG is always strongly vertical. This is why anytime > we have only one component, we prefer a vertical. A few months back, there was a discussion of whether horizontal sensors detect accelerations or tilts for distant events. The question was based on the fact that a 1 second horizontal sensor clearly saw long period (16 sec.) waves from Russia. It seems difficult to believe that 16 second waves can have a horizontal component a few thousand miles away. They would seem to be more like lunar waves. Any comments? George Harris _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: n0ssy@.......... Subject: Banda Sea quake Date: Thu, 19 Feb 1998 11:10:55 -0700 Did anyone receive an automated alert about the 6.5 quake in the Banda Sea area? Seems like I am note receiveing all of the alert messages I should be getting. Dewayne Hill _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ted Blank Subject: Re: STM Horizontal Date: Thu, 19 Feb 1998 11:36:45 -0800 (PST) Another question is, should this be a long period vertical to best record teleseismic events? I have a short period (baby Benioff) vertical but I never got very good recordings on it for distant events. Ted > > Sean Thomas > I have never observed the response of a vertical sensor to regional > or teleseismic events (eg. never built one that was kept in operation > for very long). Do the P,S and surface waves show up well?. I could see > that the surface waves' would have reasonable vertical energy. Are there > any other advantages to a vertical sensor besides the important ones you > mentioned? > Barry > Barry > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Banda Sea quake Date: Thu, 19 Feb 1998 11:41:48 -0700 n0ssy@.......... wrote: > > Did anyone receive an automated alert about the 6.5 quake in the > Banda Sea area? > I got one, but it was kinda late. I had already sent out earthquake alert bulletins to my clients when it came in. -- ---/---- Charles P. Watson Seismo-Watch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Benioff LP response Date: Thu, 19 Feb 1998 19:26:28 -0600 (CST) Barry, The Benioff is a rather narrow band instrument, even when it is operated well over damped. In the WWNSS configuration, the peak magnification (of about 150K) is actually at 0.6 seconds when the nominal magnification is 100k at 1 second. At 6 seconds, it is down to about 600, and it is about 100 at 10 seconds, and at 20 seconds, where teleseismic surface wave energy peaks, the magnificationis about 15. So it takes a good size teleseism to see much from a Benioff seis. The reason that the original worldwide network had both the short-period system (the Benioff) and the LP system (the Sprengnether, peaking at 20 seconds) was to have minimal sensitivity at 6 seconds where the storm microseisms occur. P-wave energy from teleseisms is usually around 1 second. So we had to examine two sets of records in studying a teleseism. Since the recording was made on photo paper with light-beams reflected off galvanometers, and with the horizontals, it was 6 large (10" x 36") sheets of photo paper that had too be processed daily before we could even see the data. So now we have broadband instruments, and deal with the 6-second noise with filters, either digital, or the analog classic twin-T notch that I use to reduce the 6-second noise by a factor of 100 or more. regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: LP horizontal waves Date: Thu, 19 Feb 1998 19:56:43 -0600 (CST) George, THere is a lot of energy in the horizontal component of surface waves, so even at the very low long-period magnification of a 1-second sensor, distant teleseisms will be seen. And with the typical gain of a low gain system, one might find that the magnification at 20 seconds is 1, meaning that what I see the trace on the recorder do is what I should feel, like is the earth really rising up and down several millimeters every 20 seconds. In fact it is; fortunately, we don't feel such small accelerations, and the wavelength is long enough (2km/sec x 20 seconds = 40 km) that buildings, etc, don't get broken up. Because the 20-second energy is so large, the typical magnification of an LP system (like the WWNSS) is only 1500 to 6000. Which is why a VBB system has a flat VELOCITY response, where the displacement magnification drops off as 1/period; ie if it is 100k at 1 second, it is only 5000 at 20 seconds. This is sort of an adaptive response to the geodynamics of the earth. regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Unknown Subject: STM-8 counterweight & vertical alignments? Date: Thu, 19 Feb 1998 20:01:38 -0700 Sean-Thomas, Enjoyed all 7 (?) new photos on your website. They are all sharper and clearer than most previous photos. On your hingesonly2.jpg photo, you show a counterweight on the boom & just behind the upper flexure and to the left side (as looking toward the mass). Is this really more of a balance adjustment of weight differences over the boom length, or perhaps a leveling action on the main spring, or...perhaps a coil/magnet centering aid? Basically, what are the functions of the adjustable counterweight use/s? Also,...do you have any guidelines for your seismo construction assembly where it involves avoiding any main spring "twisting", and/or non absolute vertical shifts of the boom coil? I.e.,.... carpenters or machinist squares, micrometers, calipers, etc. Perhaps these are easy questions, but I think they are relivant, for amateur homebuilders to consider and to possibly avoid future reparations afterward......such as myself - hi. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL@....... Subject: Re: TIME Date: Thu, 19 Feb 1998 23:14:24 EST To: List Participants I am using EMON and would like to set my computer clock to UTC time so that Emon will print out the UTC upon a quake event. Can this be done and if so how? Jim Allen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ted Blank Subject: Re: TIME Date: Thu, 19 Feb 1998 21:22:43 -0800 (PST) Jim, EMON does not care what time you set the PC clock. In fact, setting it to UTC is recommended. It may not keep very good time because the PC clock is not very accurate, but there are many solutions to that problem. Software like RighTime, the WWV radios are just a couple. I am adding support to EMON so that periodically you can have it run a BAT file which could do something like call a time reference service and reset the time. Ted > > To: List Participants > > I am using EMON and would like to set my computer clock to UTC time so that > Emon will print out the UTC upon a quake event. Can this be done and if so > how? > > Jim Allen > > _____________________________________________________________________ > > 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: re.balance weights, etc Date: Fri, 20 Feb 1998 00:14:59 -0600 (CST) Meredith, Re your questions re. the photos: The balance weights on the boom are just that. I do not make any serious attempt to make the main mass alone balance the spring force; there are too many variables in the setup. It is convenient that when everything is installed on the boom, an additional 50 grams or so is needed to balance it. This is then represented by the 20 gram brass stair-cutting clamp and the two or three inverted U shaped pieces of the flexure material that are moved along the boom to balance it as necessary. Sometimes I have to drop a nut or washer on the mass to get the boom to balance. I generally set it so it is against the center support post when the VRDT vane is against the bottom coil of the VRDT and the main coil is about 2mm out of the main magnet. Then in operation, the boom is about 1mm above the center support post, which also serves as a clamping post when a rubberband is looped over the boom from each end of the 1/4" bolt you see at the top of the post. As a matter of fact, the seis was in operation when I took the photos, so you see the VRDT vane is centered, and the boom is about 1mm above the center post. With the current geometry, the light sliders, at about 10 grams, need to be moved about 2 cm per degree C change. The spring is the big culprit in the temperature problem; it becomes stiffer as the temperature drops. As for any twisting in the main spring geometry, I let it do what it wants, which is to remain straght. The lower spring flexure frame is bolted to the base in two places with 1/4" NF SS bolts, and carefully set at right angles. The upper flexure frame is secured to the boom with a single centered bolt, and allowed to align itself as it wants. The task of the main spring is simply to lift the boom without imparting any torque. The hinges constrain the boom alignment and keep the coil centered in the magnet. The boom-mass-coil arrangement has some flexibility, but I have never had a problem with the alignment of the coil in the magnet changing as I make other adjustments. The Rare-Earth damping magnets/eddy current plate are adjusted after everything else is aligned. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Erich F. Kern" Subject: Down Time??? Date: Sun, 22 Feb 1998 15:07:04 -0800 Hi, Last post from this list was received here the 19th. Are you alright? Regards, Erich Kern _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: Down Time??? Date: Sun, 22 Feb 1998 16:10:16 -0800 Erich, I have a post from Sean-Thomas to the PSN on the 20th. Chas. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Peter J. Calinski" Subject: Theories on Pendulum motion Date: Mon, 23 Feb 1998 09:56:43 -0500 My son's earth science project is to build a seismometer. I have zeroed in on the S-G type. One area I need some interaction on is the pendulum. I have been reviewing in my mind the purpose and implementation of the pendulum. As I see it, what one needs to measure the motion of the earth is two platforms. One moves with the earth and the other stays stationary. Obviously the frame of the seismometer is the part that moves with the earth. The pendulum is an approximation to the stationary platform. Ideally what one wants is the long sought after "sky hook." A device that has no contact with the earth so when the earth moves, this device stays stationary and forms the reference against which to measure the earth's motion. How am I doing so far? So I come to the question of how do I eliminate the motion of the "pendulum" or more precisely the transmitter antenna of the S-G seismometer? Well, what will cause it to move when the frame moves? I see two causes of motion. Energy transmitted from the frame to the transmitter via the suspension and from air movement created by movement of the frame The second I suspect is principally due to the motion of the receiver antennas moving the air within their air gap which will cause the transmitter antenna to move. To reduce the transmission of energy from the frame to the transmitter, I am considering making the "pendulum" suspension from a material that can absorb the energy rather than transmit it. Something like rubber bands or a piece of innertube. I believe I want something as thin as possible so that air motion caused by the earth motion will have a minimal effect (unless I can implement the vacuum method described below). Therefore thin strong wire may be better but that could transfer to much motion to the transmitter. Any ideas which would be better, a wide band of energy absorbing material or thin strands that may transfer motion to the transmitter antenna? I am also considering making the "pendulum" very heavy so that any forces on it will cause minimal motion (increase the "m" to decrease the "a" in F=ma). To reduce the effects of the receiver antennas moving the air and causing the transmitter to move is a tough one. I see two ways I can reduce this effect. If I make the antennas out of something like screen material, I could greatly reduce the air motion effects. Alternatively, if I could house the whole device in a vacuum I could eliminate the problem. I suppose I could build a case (out of plastic) but I doubt it would maintain a vacuum very long. I might consider mounting a cheap aquarium pump inside and hope that it can "pump" the air out continuously. Of course this adds a vibration problem but I think these vibrations are at a much higher frequency than anything I would be trying to measure. I believe that if I can essentially eliminate pendulum motion, I will not need the damping function for the pendulum. I would appreciate any comments on my thoughts. Please e-mail them to me at: PCalinski@......... I will collect the comments and re post them. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Bob Thomasson <102073.3346@..............> Subject: Theories on Pendulum motion Date: Mon, 23 Feb 1998 12:33:57 -0500 << Please e-mail them to me at: = PCalinski@......... I will collect the comments and re post them.>> I suggest that comments be e- mailed directly to the psn list. It make= s for "real time" responses to different ideas, and the communication is more efficient and educational that way. Regards, Bob Thomasson _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: lahr@.................. Subject: strong motion device Date: Mon, 23 Feb 1998 15:35:22 -0700 (MST) > From evans@.................... Mon Feb 23 15:26 MST 1998 > Date: Mon, 23 Feb 98 14:16:04 PST > From: evans@.................... (John Evans) > Subject: TREMOR design released > Cc: evans@................... > > TREMOR/SOS Friends, > > With this e-mail I am announcing the report > > %A J. R. Evans > %T The design and performance of a low-cost strong-motion sensor > using the ICS-3028 micromachined accelerometer > %J U.S. Geol. Surv. Open File Rep. > %V 98-109 > %P 30 pp. > %D 1998 > > which releases our design and test results for the low-cost TREMOR > strong-motion accelerometer design. This is a high-end design among > low-cost accelerometers. It is capable of reaching urban background > noise levels. The hope in releasing it is to spark usage out there. > At least one vendor has shown significant interest in this design and > several others at least some interest. In the meantime, it is now > officially public domain and can be used by anyone. > > I will be snail-mailing hard copy to most of you in the non-profit > (i.e., research) groups. USGS rules preclude free mailings with > for-profit entities for reasons of fairness, however: > > Note that all relevant PostScript and Gerber files, including a > compressed PostScript of the report itself, are also publically > available to absolutely everyone via anonymous ftp at > > andreas.wr.usgs.gov:~ftp/pub/outgoing/evans/OFR_98_109 > > Use your e-mail address as password. Note that zip and Gerber files > must be binary ftp'd to a PC. The report is also available in a Unix > compressed PostScript file for that audience. > > Let me know if you have any questions or problems. > > Best wishes, > John > > ----------------------------------- > > Dr. John R. Evans > U.S. Geological Survey, MS-977 > 345 Middlefield Rd > Menlo Park CA 94025-3591 > > Tel: 650-329-4753 > FAX: 650-329-5143 or -5163 > e-mail: evans@................... > (NOTE: my "andreas" address is more reliable than "medicine".) > ftp: andreas.wr.usgs.gov:/ftp/pub/outgoing/evans > > ----------------------------------- > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Doug Crice Subject: Re: strong motion device Date: Mon, 23 Feb 1998 15:45:28 -0800 Can we "for-profit" folks buy the report? You know, it kind of annoys me that private enterprise has to buy the report and non-profits don't. First of all, it's private enterprise that pays the taxes, non-profits don't. Second of all, non-profits like say SRI and Stanford University have all the money in the world. Sorry, you pushed one of my conservative political buttons. Doug (proud member of the vast, right-wing conspiracy) I did think Gingrich was both stupid and crazy to pick on the USGS however. -- 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: S-T Morrissey Subject: Re: Theories on Pendulum motion Date: Mon, 23 Feb 1998 19:13:24 -0600 (CST) Peter, A seismometer consists of a simple pendulum such as you describe, but the variations are endless. All work on the principle of the inertial mass remaining at rest wrt the frame resting on the earth, and some sort of detector to sense and possibly react to relative motion of the mass and the frame. Since a weight is only a mass acted upon by earth's gravity g, the relationship of the portion of g that restores the mass to some reference point (like the center of the detector) controls the behavior of the pendulum. In a vertical sensor, the spring that lifts the mass via the boom can be configured to exert a minimal change of force over a small distance, so the change of g as the position of the mass changes is small, so the restoring force is small, making the response time or mechanical period long, and the response to earthquake wave accelerations is large. For a horizontal sensor, if it is a simple vertical pendulum, the change in g acting on the mass is large, so it is not very sensitive. If one inclines the pendulum, such as a garden gate, the restoring force diminishes, and if the angle of the boom is above horizontal, it falls to one side or the other. But just before this happens, the portion of g acting on the mass gets very small, and so it takes much more time for the mass to recenter itself, making the period increase, and the sensitivity likewise increases. The problem, as you correctly see it, is to minimize the forces transmitted from the frame to the mass. THe key word is minimize. And this is where the concept of natural or mechanical period comes in. I will aviod the math unless you ask for it. But as the period lengthens, the portion of g that is centering the mass in the detector approaches zero (your "sky hook" idea), and the sensitivity increases greatly. But this does not require any extraordinary mechanical schemes. Since a pendulum is in fact a mechanical oscillator (the portion of g that centers it works from both sides, making it swing through center), some form of damping to stop the motions that are induced by drafts, the earth's natural background noise (the 6- second microseisms), and even earthquake waves, is always necessary. If the motion is stopped rapidly with a e^-1 response, it is called critical damping, or a damping of 1. For more sensitivity, a damping of .7 (the sqrt of 2) is used in seismoneters. There is usually some air-viscosity damping (the capacitive plates of the detector you describe) that amounts to 0.2 to 0.3. So an additional 0.4 or 0.5 is needed, either from eddy currents in a copper bar or a shunted coil-magnet velocity sensor, or from the configuration of an electronic feedback system such as the VBB. So you obviously do not want to eliminate the motion of the pendulum, since its' motion wrt the frame IS the output of the seismometer. And evacuating the sensor is a needless complication, and I certainly wouldn't try it with an aquarium, which would implode. There is a description of a new homemade vertical seismometer at: http://www.eas.slu.edu/People/STMorrissey/index.html Click on the "STM-8" pages. I have not done so, but it is probable that the capacitive plate detector that you were describing will work with this sensor. It is also possible (I need to evaluate it) that the electronics that is available for the capacitive sensor will work, with minor modifications, with the VRDT detector. I hope this clarifies your ideas. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: n0ssy@.......... Subject: Tsunami Warning Date: Tue, 24 Feb 1998 08:05:54 -0700 Is there a real-time Tsunami warning server? If so where do I find it? -- Dewayne (n0ssy) & Linda (n0uqf) Hill Westminster, Colorado USA 39.83569n 105.06270w. Elev 5660ft. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: interesting data base Date: Tue, 24 Feb 1998 07:19:43 -0700 Found an interesting historic United States earthquake data base: http://www.ngdc.noaa.gov/seg/hazard/eqint.html -- ---/---- Charles P. Watson Seismo-Watch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Canie Brooks Subject: Re: Tsunami Warning Date: Tue, 24 Feb 1998 07:48:40 -0800 Tsunami Warnings come thru on OES server... check either of these 2 sites: gopher://oes1.oes.ca.gov:5555/11/edis.msg http://www.ceres.ca.gov/edis/ canie At 08:05 AM 2/24/98 -0700, you wrote: >Is there a real-time Tsunami warning server? If so where do I find it? > >-- > >Dewayne (n0ssy) & Linda (n0uqf) Hill >Westminster, Colorado USA >39.83569n 105.06270w. Elev 5660ft. > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Marnie Gannon Subject: Re: Tsunami Warning Date: Tue, 24 Feb 1998 09:13:55 -0700 n0ssy@.......... wrote: > > Is there a real-time Tsunami warning server? If so where do I find it? > They always show up here almost instantly..though right this second they will be couched in many weather alerts! gopher://oes1.oes.ca.gov:5555/11/edis.msg Marnie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: TREMOR design released Date: Tue, 24 Feb 1998 09:18:26 -0700 John- I have just printed out the PS version of your OFR from the .ZIP-file, and it looks excellent. In response to your telephone request, I have put the .ZIP-file and its contents at the following site: ftp://groundmotion.cr.usgs.gov/PSN/Evans/ Please let me know if that works. I'll get back to you when I have had a chance to look at the OFR in greater detail. -Edward John Evans wrote: > > TREMOR/SOS Friends, > > With this e-mail I am announcing the report > > %A J. R. Evans > %T The design and performance of a low-cost strong-motion sensor > using the ICS-3028 micromachined accelerometer > %J U.S. Geol. Surv. Open File Rep. > %V 98-109 > %P 30 pp. > %D 1998 > > which releases our design and test results for the low-cost TREMOR > strong-motion accelerometer design. This is a high-end design among > low-cost accelerometers. It is capable of reaching urban background > noise levels. The hope in releasing it is to spark usage out there. > At least one vendor has shown significant interest in this design and > several others at least some interest. In the meantime, it is now > officially public domain and can be used by anyone. > > I will be snail-mailing hard copy to most of you in the non-profit > (i.e., research) groups. USGS rules preclude free mailings with > for-profit entities for reasons of fairness, however: > > Note that all relevant PostScript and Gerber files, including a > compressed PostScript of the report itself, are also publically > available to absolutely everyone via anonymous ftp at > > andreas.wr.usgs.gov:~ftp/pub/outgoing/evans/OFR_98_109 > > Use your e-mail address as password. Note that zip and Gerber files > must be binary ftp'd to a PC. The report is also available in a Unix > compressed PostScript file for that audience. > > Let me know if you have any questions or problems. > > Best wishes, > John > > ----------------------------------- > > Dr. John R. Evans > U.S. Geological Survey, MS-977 > 345 Middlefield Rd > Menlo Park CA 94025-3591 > > Tel: 650-329-4753 > FAX: 650-329-5143 or -5163 > e-mail: evans@................... > (NOTE: my "andreas" address is more reliable than "medicine".) > ftp: andreas.wr.usgs.gov:/ftp/pub/outgoing/evans > > ----------------------------------- -- 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: Mike Stickney Subject: Re: interesting data base Date: Tue, 24 Feb 98 09:44:43 MST At 07:19 AM 2/24/98 -0700, you wrote: >Found an interesting historic United States earthquake data base: > >http://www.ngdc.noaa.gov/seg/hazard/eqint.html > >-- >---/---- >Charles P. Watson >Seismo-Watch ======================= Charlie: Thanks very much for pointing out this web site. I have previously requested this data for Montana but was told there was no practical way to access it all. Mike Stickney Montana Bureau of Mines and Geology Butte MT _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: jcblaine@........... Subject: Re: Tsunami Warning Date: Tue, 24 Feb 1998 09:49:28 -0800 Might want to try this too. Alaska and West Coast Tsunami Warning Center: http://www.alaska.net/~atwc/ Joan Blaine n0ssy@.......... wrote: > > Is there a real-time Tsunami warning server? If so where do I find it? > > -- > > Dewayne (n0ssy) & Linda (n0uqf) Hill > Westminster, Colorado USA > 39.83569n 105.06270w. Elev 5660ft. > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: interesting data base Date: Tue, 24 Feb 1998 10:27:06 -0700 I saw it was just made available in Oct 1997. -- ---/---- Charlie Seismo-Watch Mike Stickney wrote: > > At 07:19 AM 2/24/98 -0700, you wrote: > >Found an interesting historic United States earthquake data base: > > > >http://www.ngdc.noaa.gov/seg/hazard/eqint.html > > > >-- > >---/---- > >Charles P. Watson > >Seismo-Watch > ======================= > Charlie: > Thanks very much for pointing out this web site. I have previously > requested this data for Montana but was told there was no practical way to > access it all. > > Mike Stickney > Montana Bureau of Mines and Geology > Butte MT > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Unknown Subject: RE: Tremor Postscript file Date: Tue, 24 Feb 1998 14:18:28 -0700 Hi everyone, No computer guru here. Anyone know of a postscript to microsoft word converter....or reader, viewer, or any kind of free download program that allows access. Any suggestions or recommendations or donated ? for simply viewing the files? Curiosity thing. Running windows 95 and Netscape. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Terence Dowling Subject: Re: Tremor Postscript file Date: Tue, 24 Feb 1998 14:03:35 -0800 psn-l-return@.............. wrote: > > Hi everyone, > > No computer guru here. Anyone know of a postscript to > microsoft word converter....or reader, viewer, or any kind of > free download program that allows access. Any suggestions > or recommendations or donated ? for simply viewing the files? > Curiosity thing. Running windows 95 and Netscape. > > Thanks, Meredith Lamb PostScript is really a programming language and a postscript program usually used to encode a device independent final form representation of a document. Its that "usually" that makes things complex. Remember that the only way to know what a program will do is to execute it! All that said, is there help? Several possibilities exist: 1) there are printers that understand PostScript. 2) there are programs/drivers that can convert most PostScript programs into PDF form. There is a free PDF viewer (Acrobat Reader) available for essentially all platforms at www.adobe.com. 3) there are "free" PostScript viewers (ghostscript) available from a variety of sources but this usually requires something more than novice but hopefully less than guru skill. Best done in consultation with someone locally since the potential for confusion is great. 4) Ask the "source" of the document to produce PDF instead of PostScript because that is more portable, there are free viewers for most platforms, and the resultant file is usually smaller. (Note that the US govt. has standardized on PDF in many areas.) Note: I work for Adobe, the developer of PostScript and PDF. I'm not an Adobe spokesperson so these are my own views and not official Adobe policy. Also, PostScript and PDF development are not part of my job assignment. -- Terence Dowling (408) 536-3856 Adobe Systems Inc. dowling@......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: lahr@.................. Subject: RE: Tremor Postscript file Date: Tue, 24 Feb 1998 15:07:57 -0700 (MST) Meredith, You can get gswin.exe and gsview.exe free on the web. There are a few files involved, so follow the download instructions. Search for these filenames or for "ghostscript". JCLahr > Hi everyone, > > No computer guru here. Anyone know of a postscript to > microsoft word converter....or reader, viewer, or any kind of > free download program that allows access. Any suggestions > or recommendations or donated ? for simply viewing the files? > Curiosity thing. Running windows 95 and Netscape. > > Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: Tremor Postscript file Date: Tue, 24 Feb 1998 14:47:54 -0800 Go to: http://www-ts.digital.co.kr/~shlee/pub.html and download: rops.zip This is a postscrip viewer program. "RoPS runs Under Microsoft Windows (3.1, 3.11, NT, Windows-95). Both 16 and 32-bit versions are available. You will need to install Microsoft's win32s system to run the 32-bit version of the program under 3.1x. RoPS requires at least 4Mb of memory to function efficiently." Charles R. Patton _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: Tremor Postscript file 2nd thoughts Date: Tue, 24 Feb 1998 16:27:30 -0800 Re postscript reading and printing: Well, I just tried to down load from the http://www-ts.digital.co.kr/~shlee/pub.html and didn't get anywhere (the site is down or some such), so another site is: http://www.missouri.edu/~c717733/guitar.htm and then towards the bottom of the page you can download: rops.zip This one did work for me this afternoon. Unfortunately, ROPS doesn't want to read the manual. It does alright on the two schematic pages, although when printing out in my machine it reduces the size to almost unreadable. You're supposed to be able to copy and paste, so this might be a more viable route, but I haven't tried it. I'm fortunate to have a postscript compatible HP laser printer (a 5SI) here at work, and I just drop to DOS and copy the xx.ps files to LPT1 where they all printed out just fine. Charles R. Patton _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Unknown Subject: Postscript viewers for about any platform Date: Wed, 25 Feb 1998 01:43:15 -0700 First off, thanks to John Lahr, Charles Patton and Terance Dowling for the reply msgs in my quest for a program that would enable me to read the postscript file by John Evans of the USGS, entitled "The design and performance of a low-cost strong-motion sensor using the ICS-3028 micromachined accelerometer". The file is on ftp://groundmotion.cr.usgs.gov/psn/evans It turns out that one may need 2 interrelated programs for the complete file, and these are Ghostscript & Ghostscript Viewer which are on the internet at: http://www.cs.wisc.edu/~ghost/aladdin/get510.html http://www.cs.wisc.edu/~ghost/gsview/index.html You will have to particularly read the "Obtaining Alladdin Ghostscript 5.10", carefully for your platform which includes, Unix & VMS, OS/2, MS-DOS & MS-Windows and Macintosh program choices, to fit your machine/operating system. Both GSview & GS need to be on your machine, but I found that GSview will read, view and print out on my old HP Deskjet 500 the entire file. Both are free. The files are sent via FTP. The loading & setup are not well described and confusion was an appropriate term for this novice. Save all the ZIP files....until after the program is running...for transfer between each. The RoPs viewer as Charles Patton noted will display and print out only the schematics....which was my experience also. However it it does have a view button which will zoom in 2 too 3 times, which will enlarge the schematics for printout, which is good for bi-focal people like me. The RoPS 32 4.4, I used is available at a number of locations, but I used: http://www.download.com/PC/Result/TitleList/1,2-0-a-0-0-b-1,00.html RoPS is a shareware program. It would download about 15 of the 30 pages and incur a fault and hence no viewing of anything outside of the individual schematics, which is where the enlarged printout value comes in. I suppose on another file it may work fine..... This a windows only product, but of 16 or 32 versions. The article itself is very interesting and well laid out; including a list of electronic parts & cost, and even two "C" programs for electronic components (which I know zero about), that are available. Worth looking at for sure. Gained a engrossing article & a program for more viewing sometime..... Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Seisguy@....... Subject: Brief earthquake off South Island sways NZ capital Date: Wed, 25 Feb 1998 09:30:59 EST Brief earthquake off South Island sways NZ capital WELLINGTON, Feb 25 (Reuters) - An earthquake centred just off New Zealand's South Island coast caused slight and short tremors in the capital Wellington early on Wednesday. The Institute of Geological and Nuclear Sciences said the subsea quake, measuring 5.4 on the Richter scale, occurred at 6.18 a.m. (1718 GMT) and lasted for about 10 to 15 seconds. There were no initial reports of damage. Seismologist Ken Gledhill said the epicentre was about 21 km (12.5 miles) below the ocean's surface and about 20 km southeast of Cape Campbell. Gledhill said the quake was unusual because not many people on the South Island appeared to have felt it, although it had clearly rippled through the capital at the southern tip of the North Island, about 90 km from the epicentre. ^REUTERS@ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: SW6079@....... Subject: W W V What Gives? Date: Wed, 25 Feb 1998 21:36:23 EST I tuned into what I believe to be WWV this evening. It sounds like RID (the Russian time station) No solar flux reports, no I.D.s , weird. More importantly, nothing I can detect (pun intended) that would serve as a reference. A couple of times I heard what I think was a data burst. Thanks, Mike. aka sw6079@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Unknown Subject: Re: W W V What Gives? Date: Thu, 26 Feb 1998 03:23:48 +0000 At 21:36 02/25/98 EST, you wrote: I have tuned to all of the WWV freqs. and there is no problem other that a lot of qrn. The freqs are 2.5khz 5khz 10khz 15khz and 20khz. >I tuned into what I believe to be WWV this evening. It sounds like RID (the >Russian time station) No solar flux reports, no I.D.s , weird. More >importantly, nothing I can detect (pun intended) that would serve as a >reference. A couple of times I heard what I think was a data burst. Thanks, >Mike. aka sw6079@....... > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > Dewayne (n0ssy) & Linda (n0uqf) Hill Westminster, Colorado USA 39.83569n 105.06270w. Elev 5660ft. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Feb 26 eclipse web site Date: Wed, 25 Feb 1998 19:52:32 -0700 I my wonderings I found this site for tomarrow's event: http://www.solar-eclipse.org/le98/en/howto.html -- ---/---- Charles P. Watson Seismo-Watch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: ralvarez@........ (Raul Alvarez) Subject: Re: W W V What Gives? Date: Thu, 26 Feb 1998 02:38:48 -0700 (MST) All's well with WWV here. I use 5MHZ and it comes in very clear. Raul >I tuned into what I believe to be WWV this evening. It sounds like RID (the >Russian time station) No solar flux reports, no I.D.s , weird. More >importantly, nothing I can detect (pun intended) that would serve as a >reference. A couple of times I heard what I think was a data burst. Thanks, >Mike. aka sw6079@....... > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~ ~ ~ "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! ~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: New Station online Date: Fri, 27 Feb 1998 11:02:26 +1200 Greetings all the newest New Zealand Station is now online and has already recorded its first event (see the events server mailer) It in under the care of Alan Munro the head science teacher of SBHS Southland Boys High School, in the city of Invercargill ~250 km (crow flies ) to the SW of me in Dunedin city. im still recovering from my 3 days in hospital after a double knee operation so it may be a day or two before i feel up to updating the PSN map and database. This is the 1st of 5 planned schools to go online b4 July of this year The SBHS station is a 4.5 Hz vert g.phone from Geo-space and is using SDR for data logging. cheers Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: SW6079 Subject: WWV Date: Thu, 26 Feb 1998 19:54:37 EST Well, am I embarrassed .. I discovered last evening quite late, that the signal I was copying was actually originating wihin my computer. A perfect zero beat on all freqs for WWV, plus some very perfect sounding time clicks. Don't know what the odds are of this happening, I'm just glad I wasn't being tasked to look for extraterrestrials... Sorry, but it is kinda funny. Mike N7ORL aka sw6079@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Precession magnetometer Date: Fri, 27 Feb 1998 13:17:11 -0500 Hi gang, I think that I would like to build a proton precession magnetometer for= observing fluctuations in the earth's field. I know the general principa= l but would like some info on the gory details. I have freq. measuring equip., counters, a Rb oscillator and even an HP5370A time interval meter with an IEEE-488 interface to a computer, so that is no problem. Thanks in advance for your help. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Doug Crice Subject: Re: Precession magnetometer Date: Fri, 27 Feb 1998 10:52:21 -0800 If David Josephson is still on the net, he knows everyhting there is to know about making magnetometers. Call Geometrics (408-954-0522) and ask for their "Aplications Manual for Portable Magnetometers" and literature on the G-856. You start with a plastic container of liquid with an unbalanced polar molecule (water is one of these, but folks tend to use kerosene or decane because they ring longer). Inside is a solenoid shaped coil. Put DC current into the coil for a second or so, then turn it off and a decaying sinusoid comes out of the coil as the molecules rotate. The signal is small, microvolts, and has to be amplified. If you measure the frequency, that's related to the scaler ambient magnetic field. In california, the field is about 50,000 nanoTeslas (use to be called gammas) and the sine wave frequency is about 1000 Hz. So, to get 1 nT resolution, you will need to measure the frequency to about 0.01 Hz. The way it's done is to feed the signal into a phase lock loop which both amplifies and multiplys the signal so you can count it in a reasonably short period of time before it decays (say a second or so). There are lots of old patents and scientific articles with the details. -- 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: "James M Hannon" Subject: Re: Precession magnetometer Date: Fri, 27 Feb 1998 13:22:36 -0600 This link has a block diagram and short description of a precession magnetometer. It also has the equation for flux vs frequency. http://www.irf.se/obshb/protonmagn.html One thing to note this instrument gives the magnitude of the magnetic field only. (It is not direction sensitive.) Jim Hannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: David Josephson Subject: Re: Precession magnetometer Date: Fri, 27 Feb 1998 13:28:26 -0800 (PST) > If David Josephson is still on the net, he knows everyhting there is to > know about making magnetometers. Do I? Fortunately, I don't need to, because Doug has already told you nearly everything. > Call Geometrics (408-954-0522) and ask for their "Aplications Manual for > Portable Magnetometers" and literature on the G-856. For the others on this list, Doug and I are both alumni of Geometrics. > You start with a plastic container of liquid with an unbalanced polar etc. > The way it's done is to feed the signal into a phase lock loop which > both amplifies and multiplys the signal so you can count it in a > reasonably short period of time before it decays (say a second or so). The only other trick you need to know about in precession magnetometry is called "in phase polarization" which attempts to synchronize the turn-on of the polarizing current with the decaying motion of the protons that are still precessing, thus being able to kick more energy into them than would be the case if they were all randomly arranged as they are at rest. For a station magnetometer, you can do pretty well just by adjusting the timing of the current turn-on. Last time I looked, there was a proton precession magnetometer sensor for sale at Halted in Sunnyvale near the ham radio section, it would save you building one. It's a green fiberglass tube about 12" long and 7" diameter with brown phenolic end-plates, and was over by the ham radio section. -- David Josephson / Josephson Engineering / San Jose CA / david@............. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roseberry Subject: Re: Precession magnetometer Date: Fri, 27 Feb 1998 17:54:42 -0600 Bob: A few months ago I purchased a wonderful self-published 125-page book on magnetic field measurement, the instruments used to measure them, and very complete descriptions of those instruments -- including parts lists, schematics, and sources. I encourage you (or anyone else who may be interested in magnetic field phenomena) to visit J.M. Janicke's website at http://www.webspan.net/~magres/ Michael J. Roseberry Fort Worth, Texas, uSA Bob:

A few months ago I purchased a wonderful self-published 125-page book on magnetic field measurement, the instruments used to measure them, and very complete descriptions of those instruments -- including parts lists, schematics, and sources.  I encourage you (or anyone else who may be interested in magnetic field phenomena) to visit J.M. Janicke's website at http://www.webspan.net/~magres/

Michael J. Roseberry
Fort Worth, Texas, uSA
  From: Arie Verveer Subject: Data Site: Date: Sat, 28 Feb 1998 22:32:18 +0800 Hi This "International Data Centre" address was emailed to me by a PSN member, Mr Alby Judge. Its amazing. Just change the "Phases" parameter and find all data you need to identify those seismic recordings. The sites home page is full of useful data. Regards Arie ajbv@............ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Arie Verveer Subject: Data Site: Try again Date: Sat, 28 Feb 1998 22:37:38 +0800 Hi This "International Data Centre" address was emailed to me by a PSN member, Mr Alby Judge. Its amazing. Just change the "Phases" parameter and find all data you need to identify those seismic recordings. The sites home page is full of useful data. http://www.cdidc.org:65120/web-bin/recentevents Regards Arie ajbv@............ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Dick Webb Subject: Re: New Station online Date: Sat, 28 Feb 1998 10:37:25 -0500 I'm sure that everybody on PSN wishes you a speedy recovery. Dick At 11:02 AM 02/27/98 +1200, you wrote: > >Greetings all the newest New Zealand Station is now online and has >already recorded its first event (see the events server mailer) > > It in under the care of Alan Munro the head science teacher of SBHS >Southland Boys High School, in the city of Invercargill ~250 km (crow flies >) to the SW of me in Dunedin city. > > im still recovering from my 3 days in hospital after a double knee >operation so it may be a day or two before i feel up to updating the >PSN map and database. > > This is the 1st of 5 planned schools to go online b4 July of this year > > The SBHS station is a 4.5 Hz vert g.phone from Geo-space and is using >SDR for data logging. > >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 > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: Precession magnetometer Date: Sat, 28 Feb 1998 07:53:06 -0800 Bob, "The Amateur Scientist" section of the Feb. 1968 issue of "Scientific American" was "Building a sensitive magnetometer and an accurate solid-state timer." The magnetometer article is a how-to proton precession magnetometer. Nicholas Wadsworth, the author, built it using discrete transistors for the amplifier, which today you probably would do better (read quicker!) substituting an IC op-amp. But all the details are there. Basically he uses two (he made a gradiometer version) 1 3/8 x 2 1/3 " plastic bottles filled with distilled water and wound with 520 turns of #24 wire. Hope this helps, Charles R. Patton, Editor, Geo-Monitor _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Radio Shack 40-1349 Magnet details Date: Sat, 28 Feb 1998 18:12:46 -0700 Hi All, If you're building the STM-8, here are acouple good news details of possible interest. You can grind off the speaker cone rivet spread heads, and by then using pliers, screwdriver/wedge, with a soft surface underneath for the magnet assembly, the speaker cone fram will come off. Of course use a tape over the coil slot/center pole area. A high speed carbide deburr would probably be fastest. I used a small grinding head on my drill. The grinding head I had, wore down fast, but it worked. Underneath is a glue like substance which can be removed with a razor blade. The remaining stubs of the rivet heads can then be ground down, if desired. The rivets may have been welded underneath but only to the top plate. The steel rings only appear to be magnetically attached, there is no thru bolts. The speaker I got, the center pole was visually offset, and it measured .008"on the worst side with my calipers. This could create a moving coil rub or hangup. By using another large washer on the side and with the same angle, and a hammer, with light taps, metal to top metal ring , it moved the top plate to within .002" of an offset. Apparently the plates are only magnetically afixed and allow for some movement, which is good if necessary for adjustments. Of course, if you do this, be careful, you don't want too crack the ferrite ring and don't overly force the movement to where the ring contacts the center pole. You way wish to use metal shim to prevent this, and remove afterward. Nominally, all sides should be about .075" spacing between the center pole outside and the ID of the top ring. If it doesn't look offset, from your views, leave it alone. Of course the cone frame remnant removal is a choice. The ring centering aspect may or maynot be necessary. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Test - sorry about that.... Date: Sun, 01 Mar 1998 18:31:49 -0800 I'm just upgraded the mail server and need to do a test.... -Larry Redwood city, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Testing Date: Sun, 01 Mar 1998 19:05:33 -0800 Sorry, I need to do some testing on the mail server... -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: kathy mortensen Subject: SPEAKER SALE Date: Tue, 03 Mar 1998 10:45:04 -0700 The Radio Shack 10" 100 watt subwoofer Part Number 40-1349tz just went on sale today for $39.99 until Mar. 28th. For those thinking about building the STM-8, check it out!!! SKM (Stephen) Pilot Hill Ca. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: My trip to Univ. Northern Iowa. Date: Tue, 03 Mar 1998 22:24:36 -0800 Hi Everyone, I will be giving a presentation about the PSN later this week at the UNI. Ken De Nault, from the University and a member of our list, called a while back and ask me to come out there too talk about the PSN and WinQuake etc. They hold an Earth Science Update Conference every year. The conference is for junior and senior high school teachers. I will be leaving this Thursday morning and I'll be back on Saturday. I will leave the psn.quake.net system on, but may turn off all other equipment, so you may not see new events from my sensor starting Thursday. The event@............. event mailing list, and archive system, will still be working. I may live dangerously and leave everything on (I do have someone staying here to take care of the animals). Every time my system is down, something interesting happens.... -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: My trip to Univ. Northern Iowa. Date: Wed, 4 Mar 1998 07:30:37 -0600 Larry, Welcome to Iowa! It looks like you get to see some snow while you are here. :) Jim Hannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Computer safety when away Date: Wed, 04 Mar 1998 16:00:20 +0000 Larry Cochrane wrote: .................. > I will be leaving this Thursday morning and I'll be back on Saturday. I > will leave the psn.quake.net system on, but may turn off all other > equipment, so you may not see new events from my sensor starting Thursday. > The event@............. event mailing list, and archive system, will still > be working. I may live dangerously and leave everything on (I do have > someone staying here to take care of the animals). ...................... Hi Larry, and everyone, Why not build in some safety devices, as I shall do?.... 1.......PC program when running outputs continuously, a sq. waveform thro' a 'bit' on an o/p port from PC, (just on/off!). This is 'smoothed'and holds on a relay. This relay normally hold the mains on, so if program crashes for ANY reason, Mains trips off, and sounds house alarm. (could easily sound a 'neighbour alarm' as well!) 2.......A smoke detector mounted above equipment will also trip this same relay if detector goes off! (you can normally 'dig' into the inards of smoke detectors sold in shops and find a suitable pulse etc. which can be used to input to PC, and so deliberately 'crash' PC program above) Have a nice trip! Regards, Albert Noble (England). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Dewayne Hill Subject: Re: Computer safety when away Date: Wed, 04 Mar 1998 09:19:55 -0700 I remember hearing or reading that there is radioactive components inside a somke detector. It may not be wise to dig into one. Of course I'm getting older and my memory may be wavering. prewar wrote: > > Larry Cochrane wrote: .................. > > > I will be leaving this Thursday morning and I'll be back on Saturday. I > > will leave the psn.quake.net system on, but may turn off all other > > equipment, so you may not see new events from my sensor starting Thursday. > > The event@............. event mailing list, and archive system, will still > > be working. I may live dangerously and leave everything on (I do have > > someone staying here to take care of the animals). ...................... > > Hi Larry, and everyone, > > Why not build in some safety devices, as I shall do?.... > 1.......PC program when running outputs continuously, a sq. waveform > thro' a 'bit' on an o/p port from PC, (just on/off!). This is 'smoothed'and > holds > on a relay. This relay normally hold the mains on, so if program crashes for > ANY reason, Mains trips off, and sounds house alarm. (could easily sound a > 'neighbour alarm' as well!) > 2.......A smoke detector mounted above equipment will also > trip this same relay if detector goes off! (you can normally 'dig' into the > inards > of smoke detectors sold in shops and find a suitable pulse etc. which can be > used to input to PC, and so deliberately 'crash' PC program above) > > Have a nice trip! > > Regards, > Albert Noble (England). > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L -- Dewayne (n0ssy) & Linda (n0uqf) Hill Westminster, Colorado USA 39.83569n 105.06270w. Elev 5660ft. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: Computer safety when away Date: Wed, 4 Mar 1998 10:16:18 -0600 Albert, Around here we call this type of circuit a "watchdog". The process of outputting the square wave from the software used to be referred to as "kicking the watchdog" until it was decided that was politically incorrect. Now we "pet the watchdog". :) In our case it is necessary to keep the computer running at all costs so the circuit resets the computer to try again at running. Jim Hannon prewar@.............. on 03/04/98 10:00:20 AM Please respond to psn-l@............. To: psn-l@.............. cc: (bcc: James M Hannon/CedarRapids/Collins/Rockwell) Subject: Computer safety when away Hi Larry, and everyone, Why not build in some safety devices, as I shall do?.... 1.......PC program when running outputs continuously, a sq. waveform thro' a 'bit' on an o/p port from PC, (just on/off!). This is 'smoothed'and holds on a relay. This relay normally hold the mains on, so if program crashes for ANY reason, Mains trips off, and sounds house alarm. (could easily sound a 'neighbour alarm' as well!) Regards, Albert Noble (England). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Computer safety when away Date: Thu, 05 Mar 1998 11:09:59 +1200 At 09:19 AM 3/4/98 -0700, you wrote: >I remember hearing or reading that there is radioactive components >inside a somke detector. It may not be wise to dig into one. Of course >I'm getting older and my memory may be wavering. >Dewayne (n0ssy) & Linda (n0uqf) Hill Yes u are right Dewayne, although this radioactive source is very small, 1 micro currie level. The source is Americium 241 atomic #95 it is formed by bombarding a plutonium sample with neutrons. The level is Very Very low i have many rock samples in my collection from various uranium or mining sites around the world that are substantially "hotter". old smoke detectors are ratted for their sources for use in university radioactive experiments to determing decay rates etc. Others sources are used as well to see the different decay rates. OF COURSE THEY ARE PLACED IN LEAD CONTAINERS WHEN NOT IN USE cheers Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: My trip to Univ. Northern Iowa. Date: Wed, 04 Mar 1998 20:35:03 -0700 Larry- Good luck! I hope it goes well. I am sure it will! -Edward -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: New Station online Date: Wed, 04 Mar 1998 21:07:17 -0700 Dave- My USGS friend and colleague, Mark Meremonte, and his wife, Margaret, will be leaving for NZ this Saturday to spend a month trekking about. I have forwarded some of your PSN-L email to him so be on the lookout for a US government employee poking about. Mark is actually a very good guy. He is, like me, a seismologist who chases earthquakes with PADS (he is the one in the picture in front of the collapsed parking garage after Northridge, http://geohazards.cr.usgs.gov/engnseis/chase_eq.html ). His address is meremonte@.................. . I hope the two, or rather, three, of you have a chance to chat a bit. -Edward PS. Hope your knee is on the mend. I had an ACL reconstruction of my right knee in 1991, and the knee is pretty good, but the mind is still weak. David A. Nelson wrote: > Greetings all the newest New Zealand Station is now online and has > already recorded its first event (see the events server mailer) > > It in under the care of Alan Munro the head science teacher of SBHS > Southland Boys High School, in the city of Invercargill ~250 km (crow flies > ) to the SW of me in Dunedin city. > > im still recovering from my 3 days in hospital after a double knee > operation so it may be a day or two before i feel up to updating the > PSN map and database. > > This is the 1st of 5 planned schools to go online b4 July of this year > > The SBHS station is a 4.5 Hz vert g.phone from Geo-space and is using > SDR for data logging. > > 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 -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: New Station online Date: Thu, 05 Mar 1998 17:48:42 +1200 At 09:07 PM 3/4/98 -0700, you wrote: >Dave- > My USGS friend and colleague, Mark Meremonte, and his wife, Margaret, will >be leaving for NZ this Saturday to spend a month trekking about. I have >forwarded some of your PSN-L email to him so be on the lookout for a US >government employee poking about. Mark is actually a very good guy. He is, thanks Ed i will mail him and see if he is getting near my neck of the woods thanks for the thoughts abt my health its both my knees not replacement but so chomping and stuff within the knee OUCH take care btw still interested in comments abt seismometer burial depth info as well when u have time cheers Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Dick Webb Subject: Maps Date: Sat, 07 Mar 1998 20:18:47 -0500 For several years I have been using a map prepared in the 70's for the wwsn system. It has the station located at the center of a world map with circles of constant distance (10 degrees, 20 degrees, etc.) around it. It also has lines of azimuth radiating from the center (N15E, N30E, etc.). My copy is rather dog eared and weather beaten and I am trying to locate a computerized version, preferably one that would generate a map that I could print out. Any ideas where I might find such a program? Best regards, Dick Webb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Seisguy Subject: Mild earthquake in Scotland, no injuries Date: Sat, 7 Mar 1998 21:08:54 EST Mild earthquake in Scotland, no injuries LONDON, March 7 (Reuters) - A mild earthquake shook the west coast of Scotland on Saturday but no injuries or damage were reported. The British Geological Society said the tremor registered 2.7 on the Richter scale. Its epicentre was just east of Oban. Earthquakes are rare in Britain. ``Few are felt by the public so this was significant in those terms,'' said a seismologist from the Geological Society. ^REUTERS@ 11:42 03-07-98 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Little Lake Quakes Date: Fri, 6 Mar 1998 18:22:33 -0800 (PST) Hello All: From the looks of the depth of some of the quakes in the recent activity around Ridgecrest, it looks like there are some very shallow earthquakes being recorded there. Since it is in a known volcanic zone, does it mean that there is fluid magma movement nearby? Thanks, Frank Condon mailto:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Larry Cochrane: teleseismic record section. Date: Thu, 05 Mar 1998 16:28:53 -0700 Larry- Attached is not exactly what you asked for, but this file, SECTION.GIF, will have to do in the meantime. It is a record section of the recent Chile earthquake (see below) recorded by the vertical components of USGS National Seismic Network (NSN) stations in the US. I have also put it at the following site: ftp://groundmotion/PSN/section.gif Good luck! Let me know how it goes. -Edward Harley Benz wrote: > > ed, > > M6.4 Northern Chile on January 30, 1998 > > Harley -- 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: Subduction Zone Date: Sun, 08 Mar 1998 11:33:39 +0800 Hi All Though my station has been operating for only one month I have noticed the seismic waves to the north are heavily attenuated towards Indonesia. Indonesia is some 23 degrees North of my (Perth) Western Australia position. I do receive recordings but they are very weak compared to recordings to the East and West of that position. Do you think its possible the seismic waves are reflected, refracted or attenuated by the subduction slab of the Java Trench? Your view would be most appreciated. Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Kenneth J. De Nault" Subject: Larry's Visit Date: Sat, 07 Mar 1998 20:08:43 -0600 Greetings to all, I wanted to report that Larry's visit to our campus was a great success. He is a delightful person and we were fortunate to have him visit and talk about the PSN, WinQuake, and construction of a seismograph. He has generated a lot of interest among our Junior and Senior High School Science Teachers and my geology majors. Thank you Larry! Ken De Nault Associate Professor of Geology University of Northern Iowa _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: [Fwd: Re: My trip to... GIF of overlay you showed...] Date: Sat, 07 Mar 1998 21:13:37 -0700 -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". Larry- I just realized that I mindlessly CC'd that SECTION.GIF file to the PSN-L, and I apologize for doing that. I had hectic time trying to get a record section from Harley Benz who apparently has not been able to recover the originals. I hope all went well nonetheless. -Edward Larry Cochrane wrote: > > Thanks Ed, > > I should have asked for this sooner... is it possible for you to scan in > one of the overlays you show at the PSN meeting here in Dec.? Its the one > that everyone went nuts over showing the seismograms lined up... > > If you can, please send it to Ken De Nault at denault@....... and let him > know its for my presentation. I'm not sure if I will be able to receive > email until I get back. I'm leaving tomorrow (3/5) at ~8.00 am and will > give my first talk that night when I get there. The first one is for UNI > students and on Friday is the real one... This is too high school and > junior high school teachers. > > Thanks, > > -Larry > > At 08:35 PM 3/4/98 -0700, you wrote: > > > > > >Larry- > > Good luck! I hope it goes well. I am sure it will! > >-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) > > > >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". From: Pinpoint Earthquake News Subject: Re: Maps Date: Sat, 7 Mar 1998 20:42:35 -0800 (PST) On Sat, 7 Mar 1998, Dick Webb wrote: > For several years I have been using a map prepared in the 70's for the wwsn > system. It has the station located at the center of a world map with > circles of constant distance (10 degrees, 20 degrees, etc.) around it. It > also has lines of azimuth radiating from the center (N15E, N30E, etc.). My > copy is rather dog eared and weather beaten and I am trying to locate a > computerized version, preferably one that would generate a map that I could > print out. Any ideas where I might find such a program? There is an excellent program called MAP-IT.EXE which takes up quite a bit of disk space due to its mapping database.....I had a copy back in the early 1990's but have yet to find it...It is Shareware and REAL good for finding distance and precise lat/longs...Anyone else know where it might be stored? Bob Shannon Pinpoint Earthquake Newsletter. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Pinpoint Earthquake News Subject: MapIt Date: Sat, 7 Mar 1998 21:57:15 -0800 (PST) I found Mapit at the below location. It is 5 MEG zipped and takes 15 MEG unzipped. This is the demo version which is still a super program and the price on it is dirt cheap for full fledged... Bob http://home.kiski.net/~jallison/sharewar.htm _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Dick Webb Subject: Re: Subduction Zone Date: Sun, 08 Mar 1998 08:25:04 -0500 Arie, I assume that you have a horizontal long period seismometer. If that is the case then it could be due to the orientation of the "boom". If it is oriented with the long axis N-S then it will be more responsive to quakes comming in from the E or W. If most seismisity is N of you, you should probably orient the unit E-W. Dick At 11:33 AM 03/08/98 +0800, you wrote: >Hi All > >Though my station has been operating for only one month I have noticed >the seismic waves to the north are heavily attenuated towards Indonesia. >Indonesia is some 23 degrees North of my (Perth) Western Australia position. > >I do receive recordings but they are very weak compared to recordings to the >East and West of that position. > >Do you think its possible the seismic waves are reflected, refracted or attenuated >by the subduction slab of the Java Trench? > >Your view would be most appreciated. > >Arie > > > > >_____________________________________________________________________ > >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: Hope to see you at SSA'98 in Boulder next week Date: Sun, 08 Mar 1998 14:41:13 -0700 Sean-Thomas I would like to see you sometime during the week of SSA'98. Please let me know when you are arriving and where you will be staying, and we can arange a time to meet. I would like to discuss some things related to PSN, etc. I have been somewhat out of things since Xmas, and I am sorry that I have not been able to follow up all your work and contributions to the PSN-L. I look forward to seeing next week. -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: "Frank Cooper" Subject: USING MAPIT TO LOCATE EPICENTERS Date: Sun, 8 Mar 1998 20:19:38 -0600 Thanks to Bob Shannon for sharing the webb site for the Mapit demo program. A few minutes after downloading it I was able to put the three Texas PSN stations on the map having their lat. and long. Using downloads from Larry's PSN site of the GUATEMALA (1/10/98) eq from Texas stations Plano and Buda (and my own in Friendswood) I was able in a short time to locate the epicenter on the map by drawing the great circles from their locations using the distance calculations from P and S waves (thanks Larry for Winquake). I am sure this is very elementary but I was so pleased with it I wanted to share. I plan to purchase the program. Frank Cooper, Friendswood, Texas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: mail list for quakes Date: Sun, 08 Mar 1998 20:13:53 I got droped from the auto notificaion list and can't find the address for the subscribe. This is the one that usgs has. Help! Norman Davis WB6SHI Email normd@............. Shingle Springs, Ca, USA it ain't local... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: Computer safety when away Date: Thu, 05 Mar 1998 16:00:42 +0000 Dewayne Hill wrote: > I remember hearing or reading that there is radioactive components > inside a somke detector. It may not be wise to dig into one. Of course > I'm getting older and my memory may be wavering. > N-L) Hi Dewayne, You're right. I used the wrong expression (dig). I was NOT proposing to tinker with radioactive element, BUT just check electronic cct. to find a suitable pulse/on-off o/p to feed into PC. I also overlooked to mention that o/p from PC is passed into a Freq/Volt converter and it is this o/p that holds on relay......If PC ever crashed due to fire etc. it may be that PC 'bit' o/p stays ON, so the actual presence of the sq. wave MUST be continually detected. Regards, Albert Noble (England). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Arie Verveer Subject: Subduction Zone Date: Sat, 07 Mar 1998 14:55:59 +0800 Hi All Though my station has been operating for only one month I have noticed the seismic waves to the north are heavily attenuated towards Indonesia. Indonesia is some 23 degrees North of my (Perth) Western Australia position. I do receive recordings but they are very weak compared to recordings to the East and West of that position. Do you think its possible the seismic waves are reflected, refracted or attenuated by the subduction slab of the Java Trench? Your view would be most appreciated. Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ken Navarre Subject: I'll just bet that Larry's Ticked! Date: Thu, 5 Mar 1998 23:54:48 -0800 (PST) Wasn't Larry leaving Calif. Last night? Didn't he say that whenever he shuts his system down things go BOOM!?? Thanks Larry! The Coso events have REALLY been banging away here in Sunnyvale!!!! :( Jeese, I know the feeling!... When I was on vacation a few months ago My sweetie and I took a wander up a windy paved road just north of Coso Jct. off Hwy 395. The road *used* to provide access to some hot springs just inside the borders of the Naval Weapons Center at China Lake. We happened upon a lonely Air Force sentry post manned by a sole airman and had a nice chat before he sent me back the way I came. I'd give a shiney quarter if I had the telephone number for that guy right about now. he's sitting just about on ground zero and I'd LOVE to be able to give him a jingle!!! Hope he wasn't in the outhouse when things "popped"! Ken _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Zero length springs Date: Mon, 9 Mar 1998 09:53:20 -0500 Sean-Thomas, Many thanks and 2 (two) attaboys for all your epistles on this net. T= he STM-8 is a fascinating design which I may build but your comments about peripheral matters are also interesting. I have learned a lot. I have been pondering the matter of "zero length springs" (ZLS). Can coil ZLS's be purchased, and if so, where? Can they be ordered from spring manufacturers (of which there are many, many in Thomas' Register)?= Aki & Richards (vol. 2, p482) give a test to see if a helical spring i= s a ZLS. I have tried this test on hardware store springs considering only= those where an appreciable force must be applied before any separation of= the coils is seen and found that they fail the test. (I have not discovered how to apply this test to a leaf spring.) My measurements of force vs. length on these springs showed that the linear (Hookian) part of the force vs. length plot does not extrapolate back to something near zero force at zero length. Is this extrapolation= a sufficient criterion for a ZLS? In your message of 1/3/98, you state that your STM-8 leaf spring 'start= s to exhibit "zero length" behavior, where the restoring force is constant for small changes in length, when the ends are about 5.5 to 6" apart'. = I could not visualize why this should be so I set out to measure the force-deflection curves of a leaf spring. I used a hack-saw blade (with the teeth ground off) 12.5" long, 0.025" thick and 0.5" wide. This could be bent beyond the point where the gap between the two ends was less than 5" without permanent deformation. One= end of the blade was rested on the pan of an electronic balance and the force was applied vertically with an 18" Starrett heighth gage (which has= a vernier reading to 0.001"). The ends were not clamped, they just pressed= against the balance pan and the finger of the gage. With the bow toward one face (say the A faceof the blade), the force-% deformation (F-D) plot was very nearly linear (looks like Hooke's law has= not been repealed). (I define % deformation as the distance between the free ends divided by the blade length.) An F-D plot with the bow toward= the B face, I found a shallow min. in the curve. Was this difference due= to a slight unloaded curvature of the blade? Well, try it with more curvature-- I plastically deformed the blade (just bending it with my fingers) to a= roughly circular shape. The amount of curvature was such that a line connecting the two ends was 1/2" from the center of the blade (with no load, of course). Now the F-D plot (with the bow under load opposing the unloaded bow) showed a much larger and broader minimum! Is this 'zero length behavior'= ? Further plastic deformation so that the unloaded bow was 1.25" gave an F-D plot with a yet deeper and broader minimum. ( I tried to go farther with the plastic bending but broke the blade.) After each of the measurements, the blade had the same curvature as originally, i.e., the measurement did not deform the blade plastically. In a plot with the force along the Y-axis and the %compression along X,= the curve (with increasing %compression) falls rapidly to the broad minim= um (a high negative spring 'constant'). After the minimum, the curve rises slowly (a smaller 'spring constant). These meas. are summarized in the table. = In the table, Clm. A is the shape of the blade. Clm. B is the %compression where the minimum force in the F-D plot occurs. Clm. C is the slope of the curve half way between the highest force and= minimum force (i.e., a sort of 'spring constant for this part of the curve). Minus means that the force is getting smaller as the deformation= increases (maybe Hooke's law has been repealed, at least locally). Clm. D is the slope at 40% compression. Clm. E is the force (grams) at 40% compression (when the ends of a 12.5= " blade were 5" apart). Clm. F is the change in gap (inches) required to= go from 1.025 * min. force on the left of the min. to 1.025 * min. force = on the right of the min. I take this as a measure of the width of the 'zero= length' behavior region. Clm. G is the same range expressed as % of the 12.5" blade length. A B C D = = E F G shape % g/in g/in = = grams inches % sl. bend 1 -- 34 = = 701 -- -- 0.5" bend 9 -60 32 = = 721 2.8 22 1.25" bend 18 -62 29 = = 770 3.4 27 In the 0.5" and 1.25" bend meas., the plots were never Hookian althoug= h the departure at high compression might be due to flexing of the gage. I was surprised at the width of the nearly constant force region. = I suppose that all this is well-known to seismometer designers but, if not, might it have some application? I will e-mail the plots to you in .PCX format (which can be viewed by PCPAINTBRUSH). = Bob Barns = _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: I'll just bet that Larry's Ticked! Date: Mon, 09 Mar 1998 08:53:00 -0800 Ken, et al -- I stopped in Coso Jct. for a break last WEDNESDAY night while traveling up 395. If it had only been THURSDAY night. Right place, wrong time. -- Karl At 11:54 PM 3/5/98 -0800, you wrote: >When I was on vacation a few months ago My sweetie and I took a wander up >a windy paved road just north of Coso Jct. off Hwy 395. The road *used* >to provide access to some hot springs just inside the borders of the >Naval Weapons Center at China Lake. We happened upon a lonely Air Force >sentry post manned by a sole airman and had a nice chat before he sent me >back the way I came. I'd give a shiney quarter if I had the telephone >number for that guy right about now. he's sitting just about on ground >zero and I'd LOVE to be able to give him a jingle!!! Hope he wasn't in >the outhouse when things "popped"! _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: Zero length springs Date: Mon, 9 Mar 1998 11:16:39 -0600 I performed a similar experiment with a piece of clock spring bent opposite its normal curvature and got a nearly flat portion of the force versus distance curve. The thing to remember with the leaf spring is that the period is determined by the spring constant which in this case is not "constant" but rather is the rate of change of force vs distance at the amount the spring is bent in operation. Does this make sense? Jim Hannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roger Baker Subject: Re: Zero length springs Date: Mon, 09 Mar 1998 12:02:40 -0600 Friends, >I performed a similar experiment with a piece of clock spring bent opposite >its normal curvature and got a nearly flat portion of the force versus >distance curve. > >The thing to remember with the leaf spring is that the period is determined >by the spring constant which in this case is not "constant" but rather is >the rate of change of force vs distance at the amount the spring is bent in >operation. >Does this make sense? > >Jim Hannon In response to Jim Hannon's remarks, it is my understanding that the important function of zero length springs is to make spring deflections linear with applied force. But if the springs do not deflect appreciably, as in the case of force feedback instruments, which are slowly becoming the standard, then this advantage does not matter much any more. Force feedback is lots easier to implement than it might once have been, due to op amps, etc. If force feedback is not employed, however, there is an advantage in using the most sensitive displacement detector possible so that this source of nonlinearity will be minimized. In other words it is better, for this reason at least, to use a stiff spring (the deflection of which will tend to be more linear for a small percentage of deflection), in combination with a sensitive detector than it is to use a floppier spring and less sensitive detector. --Yours, Roger Baker _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: stuart@................. Subject: Date: Tue, 10 Mar 1998 11:47:33 -0800 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Rex Klopfenstein Jr" Subject: Proton Precession Magnetometer-Construction Questions Date: Tue, 10 Mar 1998 18:51:21 -0500 I have read several of the posts on proton precession magnetometers. I now would like to attempt to build a magnetometer unit. I have looked through the the university library system in Ohio and had little success finding information on the theory & construction of the proton precession magnetometer. I have got a lot of information from the posts and several web pages. I however still have several questions. 1. What is the optimal (normal) size of the cylinder of liquid (diameter & length)? 2. How are the coil windings distributed over the surface of the tube? How many windings? Is there some minimum magnitude of field that should be applied to liquid in tube? 3. Would standard schedule 40 or 80 PVC pipe work for housing? The electronics seem somewhat straight forward. I would use a basic frequency counter (clock, counter, latch, display, pulse shaper and gate logic) to shape signal from magnetometer and count for 1 second. To get the resolution of 0.01Hz from the display, use a phase-locked loop to multiple magnetometer frequency by 1000 (move decimal point 3 places left on display). Also, check the PLL jitter parameters! By the way, is there something any better than the 4046 for a PLL out there now? The raw signal from the magnetometer would also have to be amplified with a high impedance opamp up to a useful level for input into the PLL. One could also automate the charge/read cycle to provide a relative continous reading and sync with charge with the decay of proton precession. I do have one question, should one blank or ignore the signal from magnetometer for a time period after disconnecting power for sense windings? From what little information I have found, I am wondering if my design interpretations (or misinterpretations!!) are reasonalble?? Rex Klopfenstein, Jr Bowling Green, OH _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: David Josephson Subject: Re: Proton Precession Magnetometer-Construction Questions Date: Tue, 10 Mar 1998 17:35:01 -0800 (PST) > would like to attempt to build a magnetometer unit. I have looked through > the the university library system in Ohio and had little success finding > information on the theory & construction of the proton precession > magnetometer. I have got a lot of information from the posts and several > web pages. I however still have several questions. Contact Geometrics and get copies of _Application Manual for Portable Magnetometers_ and see if they can find you an old copy of a G-801 manual. All will be clear (that was when they put complete circuit descriptions in manuals) > 1. What is the optimal (normal) size of the cylinder of liquid (diameter > & length)? > 2. How are the coil windings distributed over the surface of the > tube? How many windings? Is there some minimum magnitude of field > that should be applied to liquid in tube? Normally the coil is a solenoid about as long as it is in diameter, with this dimension typically 1.5 to 4 inches. Two coils are usually used, in series opposing, so that the external 60 Hz field doesn't swamp the front end. (Connect the two coils in series, apply an external field, and adjust the number of turns of one coil so that the field is nulled.) The coils are wound wet (wire dipped in varnish), on a mandrel, and the mandrel removed. Typical values are 15 to 100 mH (total) and the coil is wound of #22 to #14 wire to pass the polarize current, which is on the order of 1/4 to several amps. Then the coils are simply immersed in a container of fluid (water or kerosene). > 3. Would standard schedule 40 or 80 PVC pipe work for housing? Yes. > The electronics seem somewhat straight forward. I would use a basic > frequency counter (clock, counter, latch, display, pulse shaper and gate > logic) to shape signal from magnetometer and count for 1 second. To get Unless you put a lot of polarize current into the coil, and have made a large coil, and there is very low magnetic gradient across the coil, the precession signal will last for a fraction of a second, with an exponential decay in amplitude. So you need the PLL anyway to lock to the bursts of signal that you get. > the resolution of 0.01Hz from the display, use a phase-locked loop to > multiple magnetometer frequency by 1000 (move decimal point 3 places left > on display). Also, check the PLL jitter parameters! By the way, is there > something any better than the 4046 for a PLL out there now? The raw signal Probably; but the 4046 works OK. > from the magnetometer would also have to be amplified with a high impedance > opamp up to a useful level for input into the PLL. One could also automate Note the impedance is on the order of tens of megohms. Use a relay to switch the polarize signal on and off, or a *very* low leakage bipolar transistor. Mind the inductive spike when you turn off the pol current. > the charge/read cycle to provide a relative continous reading and sync with > charge with the decay of proton precession. Yes, all of the above exists in modern proton magnetometers. The signal is quite small, so the coil is tuned to resonate at the Larmor precession frequency (around 0.039 Hz per nT) which raises the Q of the system. > I do have one question, should one blank or ignore the signal from > magnetometer for a time period after disconnecting power for sense > windings? Yes. This timing is critical. Polarize-mute-read. When you look at the signal coming from the preamp you'll see what the time values should be. I'm not sure what you mean by "sense windings." Normally the same winding is used for polarize and sense. > >From what little information I have found, I am wondering if my design > interpretations (or misinterpretations!!) are reasonalble?? Reasonable enough. You should be able to find a proton mag in the geophysics department of any local college; see ifyou can borrow it and look at the waveforms. It will be made by one of three companies and the older units are all very similar. -- David Josephson / Josephson Engineering / San Jose CA / david@............. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Rex Klopfenstein Jr" Subject: Re: Proton Precession Magnetometer-Construction Questions Date: Tue, 10 Mar 1998 21:28:56 -0500 > Contact Geometrics and get copies of _Application Manual for Portable > Magnetometers_ and see if they can find you an old copy of a G-801 > manual. All will be clear (that was when they put complete circuit > descriptions in manuals) > I have a copy of the Application Manual, I however will try to get a copy of the G-801 manual. Thanks for the Information. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: LCD's Date: Tue, 10 Mar 1998 18:57:57 -0800 Hi All I have a few LCD chips. The one I am currently looking at is a 7 digit LCD in a 50 pin DIP. I would like to know if any one knows the standard pinout for a digit and power. It's not an intelligent LCD display. I understand them. I hope to attach one to a processor to display a 7+ digit number. I assume there is a backplane pin and pins for each of the 7 segments. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Re: DC sensors and coil/mag sensors Date: Tue, 10 Mar 1998 20:13:02 -0700 prewar wrote: > A minority of folk on PSN live in places far removed from the, > 'Pacific Ring of Fire', so we don't get big traces. To augment > my interest I have DELIBERATELY gone for a Hall Effect DC > sensor on both my NS and EW beams. I use PC o/p to stop ALL > beam drift giving me two sets of figures in the PC which seem just > as interesting as 'quake data . These values show me how my > concrete pier drifts day by day, which I am finding very interesting! > The mag/coil sensor would be 'transparent' to any of this interest. > I seem to have the 'plague' you referred to above > > Regards > > Albert Noble (England). > Albert Noble, I would be interested to know the specific hall effect device that you used? As I understand them (?), most of them are switching, except for the early ones. I'am not an engineer, so, I hope some day you may publish more information on your observations and schematics. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: Proton Precession Magnetometer-Construction Questions Date: Tue, 10 Mar 1998 20:48:32 -0800 Rex Klopfenstein Jr wrote: .... > would like to attempt to build a magnetometer unit.... I repeat the post I made back on 2/28 to a similar question. **** "The Amateur Scientist" section of the Feb. 1968 issue of "Scientific American" was "Building a sensitive magnetometer and an accurate solid-state timer." The magnetometer article is a how-to proton precession magnetometer. Nicholas Wadsworth, the author, built it using discrete transistors for the amplifier, which today you probably would do better (read quicker!) substituting an IC op-amp. But all the details are there. Basically he uses two (he made a gradiometer version) 1 3/8 x 2 1/3 " plastic bottles filled with distilled water and wound with 520 turns of #24 wire. **** The article discusses the charging current, coil winding, etc. The only problem is that it only used an audio output -- you listen to the beat note between the two coils which then is indicative of a non-uniform field. The author was using it to do field surveying type problems. If I was constructing this I think that instead of trying to use a phase lock loop, which takes time to settle, I would try and do a period measurement for a few cycles. Using a 10 MHz clock, or with effort up to 100 MHz, you could count for only a few cycles of the precession tone which will be in the neighborhood of 2 KHz or so. That way you would get approx. 5 K counts per cycle of tone which equates to a precision of 0.02% in only one count. It will take over two seconds to get that same precision by counting the tone itself, and if there is a field inhomegenity, it will quench the tone quite rapidly. Hope this helps, Charles R. Patton, Editor, Geo-Monitor _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: Proton Precession Magnetometer-Construction Questions Date: Tue, 10 Mar 1998 20:50:37 -0800 Rex Klopfenstein Jr wrote: .... > would like to attempt to build a magnetometer unit.... I repeat the post I made back on 2/28 to a similar question. **** "The Amateur Scientist" section of the Feb. 1968 issue of "Scientific American" was "Building a sensitive magnetometer and an accurate solid-state timer." The magnetometer article is a how-to proton precession magnetometer. Nicholas Wadsworth, the author, built it using discrete transistors for the amplifier, which today you probably would do better (read quicker!) substituting an IC op-amp. But all the details are there. Basically he uses two (he made a gradiometer version) 1 3/8 x 2 1/3 " plastic bottles filled with distilled water and wound with 520 turns of #24 wire. **** The article discusses the charging current, coil winding, etc. The only problem is that it only used an audio output -- you listen to the beat note between the two coils which then is indicative of a non-uniform field. The author was using it to do field surveying type problems. If I was constructing this I think that instead of trying to use a phase lock loop, which takes time to settle, I would try and do a period measurement for a few cycles. Using a 10 MHz clock, or with effort up to 100 MHz, you could count for only a few cycles of the precession tone which will be in the neighborhood of 2 KHz or so. That way you would get approx. 5 K counts per cycle of tone which equates to a precision of 0.02% in only one count. It will take over two seconds to get that same precision by counting the tone itself, and if there is a field inhomegenity, it will quench the tone quite rapidly. Hope this helps, Charles R. Patton, Editor, Geo-Monitor _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: Larry's Visit & System problems while I was gone Date: Tue, 10 Mar 1998 21:05:19 -0800 Hi Everyone, Sorry for not sending out information on my trip sooner. I have been fighting some fires since I've been back.... First, I would like to thank Ken for inviting me out there. He was a very gracious host. The trip was very interesting and I had a great time. I must admit that one of the highlights of the trip was meeting Ken's timber wolf / dog hybrid (as you can tell I'm an animal lover). This wonderful animal, named Buck, is 7/8 wolf and I just don't have the writing skills to describe him. He takes Buck to work with him, and the staff and students just love him. While I was out there the weather was pretty nice, but cold (well for us Californians ). They have been having a very mild winter, but it was still cold for me... When I arrived it was snowing a little. Since we normally don't get snow where I live (thank god!), and I'm not a skier etc, it was nice to see it. The next day the sun came out and melted most of it away. Apparently a big storm hit just after I left on Saturday, so I got out of there just in time! For the lectures I talked about history of the PSN, how we record data etc...I also showed how WinQuake works and how to download event files using the Web. Everything went fine in Iowa, it was when I got back all hell broke loose. First my main system, that I turned off while I was away, would not boot up. I normally leave my systems running all of the time. Apparently it didn't like being turned off for a few days. The problem was the hard disk, and after removing it from the system I ended up dropping it, from a few inches, as a last resort, to see it would "help". Well it did! After dropping it, the platter was able to spin up and the system booted up just fine. I looks like the motor / platter was frozen and jolt freed it up. So the saying of "if all else fails just kick it" does work sometimes. After the system booted up I went to read my email, only to discover that I had none. Well that was impossible, I get a lot of mail each day (a lot of it spam) so I knew something was wrong. It turned out that the email server, on my other system that has the web and email server on it, had not started up properly after the last time I rebooted the system. I rebooted the system just before I went to Iowa, last Thursday. So on Saturday, about 10:00Pm local time, I restarted the email server and email started to flood in. I then found that the backup system I have access too, the one that is used for the NewEvent mailing list, was down. I spent most of Sunday getting this system up and running again. By Sunday night I had all of my systems up and running again. And as I predicted there was not one, but two interesting series of events while I was gone and my SDR systems and sensors where turned off. I missed the new series of events near Mammoth Lakes and three events closer to me. They where located about 8 miles south of me, near Menlo Park, and in the M2.3 range. I think they happened during the day, so the local ground noise may have drowned them out. Anyway, I had a great trip, and I would like to thank Ken and the other staff at UNI for having me out there. -Larry Cochrane Redwood City, PSN At 08:08 PM 3/7/98 -0600, you wrote: >Greetings to all, > >I wanted to report that Larry's visit to our campus was a great success. He is >a delightful person and we were fortunate to have him visit and talk about the >PSN, WinQuake, and construction of a seismograph. He has generated a lot of >interest among our Junior and Senior High School Science Teachers and my geology >majors. > >Thank you Larry! > >Ken De Nault >Associate Professor of Geology >University of Northern Iowa > > > >_____________________________________________________________________ > >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: Arie Verveer Subject: Re: Subduction Zone Date: Wed, 11 Mar 1998 20:01:52 +0800 Hello Dick < Dick Webb > Thanks for the suggestion about the orientation of the "boom" and I do agree that its direction is important with regards the wave direction. But as usual, I forgot to explain the fine detail, I have have two sensors (SG type) orientated N-S and E-W. Sorry about that. Mr John Hernlund suggested that the waves can be refracted by the subduction slab and I could check this fact by observing the wave arrival times. As Mr Hernlund said. "...... what you will see is a quicker arrival time for the waves passing through the slab because it is more rigid than they would normally be..." And believe it or not, this is exactly what I see. The waves appear about a second earlier than the predicted times from seismic waves to my north, that is through the Java trench. Amazing. I plan to construct a Table of arrival times as the events occur. Regards Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: ERICH777 Subject: Southern California Event Date: Wed, 11 Mar 1998 07:43:10 EST To : psn-l@............. Subject:Southern California Event Time: 0422 PST approx. Date: 98/03/11 Station Location 33,51.00N 118,8.33W Remarks; Approx 36 miles away Approx M4+ < A n Subject: Lancaster's article Date: Wed, 11 Mar 1998 10:33:11 -0500 Hi gang, Don Lancaster devoted a whole article to resources on seismology. It contains a buch of stuff I was not aware of. Since the magazine will probably get lost around here, I typed much of the info into a file. This file is attached in the hope that some of you will find something = of interest. Bob Barns From: Stephen & Kathy Subject: STM-8, etc. Date: Wed, 11 Mar 1998 12:23:07 -0800 To all, The 4.5 from redlands Ca. rolled through Pilot Hill Ca. at 12:20:18 UTC +/- my clock error! That's about 385 miles away!!! The 5.2 & 4.8 on the 5th, just started to saturate my data logger. They were about 260 miles away!! I'm now using the STM-8 mechanism but untill I get the electronics built I'm still using the oil damping and simple magnet and coil sensor. It is working fine but seems to try to oscillate when the temp. drops to about freezing. It has a natural period of about 2.7 sec (I made it about 20 inches long, I can always cut it down later if I want) I found the brass for the spring ends (round and square) at a hobby shop, in 12 or 36 inch lengths. I used a die grinder to cut slots in the spring rather than trying to drill holes (rough on bits). I used my dremel to cut the slots in the brass. This way I was able to cut the slot for the spring just wide enough for the spring rather than cutting the slot for the whole length of the brass. It made the ends more stable for soldering the flexures. (personal choice) COMPUSA has Mathcad-7 (standard) for $129.99 with $10.00 instant rebate and a $50.00 mail in rebate. Makes it fun to play with the transfer functions!!!! Enough for now, SKM (Stephen) Pilot Hill Ca. USA lat./long. 38.828N / 120.978W _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: ralvarez@........ (Raul Alvarez) Subject: Re: Lancaster's article Date: Wed, 11 Mar 1998 17:26:23 -0700 (MST) Hi All, Be aware that some of the URL's published in the magazine do not connect properly or at all. It appears there were some typos. Just FYI. 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! ~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: ralvarez@........ (Raul Alvarez) Subject: Re: Proton Precession Magnetometer-Construction Questions Date: Wed, 11 Mar 1998 17:33:22 -0700 (MST) Rex wrote: >I have read several of the posts on proton precession magnetometers. I now >would like to attempt to build a magnetometer unit. I have looked through >the the university library system in Ohio and had little success finding >information on the theory & construction of the proton precession >magnetometer. I have got a lot of information from the posts and several >web pages. Hi Rex and all, Did you save the url's of the magnetometer web sites that were useful? I checked around when this thread started, and found mostly company advertisements, but no good how-to info. Any good locations?? 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! ~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Detected Precursor to Redlands M4.5 Date: Wed, 11 Mar 1998 18:39:32 -0800 (PST) Hello All: Well, I admit that I should have posted my observations more timely! Unfortunately, I was occupied with other issues and could not post this information prior to this morning's seismic event. On March 10, 10:00am PST, I detected a geo-magnetic field disturbance of significant importance in the area near Fontana, CA. It lasted for approximately 4 hours and subsided by the afternoon. The readings as of this morning and well into the late afternoon are still indicating that there is something more to come from this event. I feel that it is a precursor to a much larger event that will possibly happen soon. There is no way I can pinpoint the exact hour and date! All that I can absolutely report to all of you is that my data observations say that the San Jacinto Fault Zone isn't finished doing what it started this morning. If there are any similar observations about this event I would certainly like to hear about them. Thanks, Frank Condon mailto:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Detected Precursor to Redlands M4.5 Date: Thu, 12 Mar 1998 16:31:42 +1200 At 06:39 PM 3/11/98 -0800, you wrote: >Hello All: >I detected a geo-magnetic field disturbance of significant importance in the >area near Fontana, CA. It lasted for approximately 4 hours and subsided by >the afternoon. The readings as of this morning and well into the late >afternoon are still indicating that there is something more to come from > >Thanks, >Frank Condon Frank Jst to let u know ur geo-magnetic field disturbance coincides with a interplanetary shockwave arriving from the sun. this shockwave had produced the best auroral displays for some 6 months. This shockwave has caused minor to major storm levels. it is probable that this is what u have detected which means ur magnetometer is working well. 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: "Rex Klopfenstein Jr" Subject: Re: Proton Precession Magnetometer-Construction Questions Date: Wed, 11 Mar 1998 22:15:53 -0500 --------- > Did you save the url's of the magnetometer web sites that were useful? > I checked around when this thread started, and found mostly company > advertisements, but no good how-to info. > Any good location I too only found commerical items listed in most web searches. The only useful information came from the PSN list. I am just toying with the idea to build a magnetometer. Rex K. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Detected Precursor to Redlands M4.5 Date: Wed, 11 Mar 1998 21:03:31 -0800 (PST) > Jst to let u know ur geo-magnetic field disturbance >coincides with a interplanetary shockwave arriving from the sun. this >shockwave had produced the best auroral displays for some 6 months. This >shockwave has caused minor to major storm levels. > > it is probable that this is what u have detected which means ur >magnetometer is working well. > > >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 > > Hi Dave: So that's what it was! Any coincidence in my book is just another cock-eyed observation. Oops!... I guess I'll have to wait and see what happens next. The instrumentation was really active all day long! I haven't seen that much activity since the Landers 1992 sequence. Thanks, Frank condon mailto:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" PS. Maybe it's a precursor to that asteroid coming towards the Earth that I heard about on the news today? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: [Fwd: Daily Summary of Solar Geophysical Activity for 11 March] Date: Wed, 11 Mar 1998 23:11:24 -0700 Frank, Here is the daily solar summary for March 11. There is a notation of the active to major storm conditions for the geomagnetic field. Ah, check out the solar wind velocities. Them some pretty stiff winds. They usually hang in the 200-400 km/sec range, but 575 km/sec! Zowie!! -- ---/---- 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 From: watson@................ (Charles Watson) Subject: [Fwd: Daily Summary of Solar WIND Spacecraft Data for 11 March] Date: Wed, 11 Mar 1998 23:15:52 -0700 Here is a bit more info on the unusal solar winds on March 11, including a graph of measurements over time. -- ---/---- Charles P. Watson Seismo-Watch From: prewar Subject: Re: DC sensors and coil/mag sensors Date: Thu, 12 Mar 1998 07:39:19 +0000 meredith lamb wrote: > I would be interested to know the specific hall effect device that > you used? As I understand them (?), most of them are switching, > except for the early ones. I'am not an engineer, so, I hope some > day you may publish more information on your observations and > schematics. Hello Meredith, My devices are Honeywell LOHET II's. As you say, many are sold as on/off switching magnetic detectors, (and are the cheapest! ) Those I use are about $19 each. The only other requirement, other than LP filters of course, is the amplifier.....I 'lifted' mine from an article which appeared in, "Everyday and Practical Electronics", Sept. '94, "How to build an Experimental Seismograph", using Hall Effect devices. (This is an English mag. and may be be available in USA etc??) Supply requirements to LOHET II's is 8v...output swings from 2v to 6v when magnetic field swings from - 400 gauss to + 400 gauss. Only very tiny magnets, (mine are 1/4" dia x 3/4" long), seem necessary. Full i/p range to A/D converters can be obtained with about .001 inch movement of beams! Unlike coil/magnet sensing for seismos, the great DISadvantage in using Hall Effects is that beam drift can be troublesome, as unlike coil/mags (which are transparent to LONG term drift), the Hall Effects are not! It was because of this that I decided to use them, as Earth Tilt sensing is an interest of mine. But without some form of beam stabilisation, (which I've previously outlined), I found that my traces could go right off the screen(!), from day to day, when using LOHET's, on the NS and EW horizontal beams. Hope above helps..... Regards, Albert Noble (England). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Piezoelectric cable as simple seismograph? Date: Thu, 12 Mar 1998 12:39:43 +0000 > Hi everyone, Have just read an article outlining a few simple uses for piezoelectric cable....a .microphone and also a vibration alarm. I wonder if a length of this could form any basis for a simple seismo?? A length either buried/concreted in ground, or bent to form a flexible loop between ground and vert/hor seismo beams ?? If one used it as the suspension wire for a horizontal beam, one could pick up vert. component between frame and mass ? Have 2 seismos for the price of ONE ??? Has anyone carried out any tests with this cable, as to whether it can be used for 'quake detection? Over here it seems to be about 15 pounds per metre ($24), so somewhat pricey......what length would be required I wonder ?? Used for your bootlaces, you could have a seismo with you all the time !! "These boots were made for earthquakes" (walking)........ Regards, Albert Noble (England). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Robert L Barns <75612.2635@..............> Subject: Proton Precession Magnetometer-Construction Questions Date: Thu, 12 Mar 1998 10:03:03 -0500 Rex, The article in the Amateur Scientist column of Sci. American, Feb. 1968= pp 124-128 is pretty good and will answer many of your questions. One disturbing comment in this article about using such a device is tha= t the field inside buildings is so inhomogeneous that the precession signal= dies off rapidly. The use described in the article was outdoors. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Dewayne Hill Subject: USBR Server Date: Thu, 12 Mar 1998 15:33:30 +0000 Can anyone reach URL "www.seismo.usbr.gov"? I can't get there from here. Dewayne (n0ssy) & Linda (n0uqf) Hill Westminster, Colorado USA 39.83569n 105.06270w. Elev 5660ft. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Mike Stickney Subject: Re: USBR Server Date: Thu, 12 Mar 98 09:11:33 MST Dewayne and Linda: The US Bureau of Reclamation site appears to have no data listed today. It worked fine last week. -Mike Stickney Montana Bureau of Mines and Geology ==================================================== At 03:33 PM 3/12/98 +0000, you wrote: >Can anyone reach URL "www.seismo.usbr.gov"? I can't get there from here. > >Dewayne (n0ssy) & Linda (n0uqf) Hill >Westminster, Colorado USA >39.83569n 105.06270w. Elev 5660ft. > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: USBR Server Date: Thu, 12 Mar 1998 08:44:47 -0700 It is really, really slow. Hang in there. -- ---/---- Charles P. Watson Seismo-Watch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roger Baker Subject: Re: Proton Precession Magnetometer-Construction Questions Date: Thu, 12 Mar 1998 10:42:53 -0600 Friends, I will say that I tried to build a version of a proton precession magnetometer a few years back, roughly based on the Scientific American version, but never could hear an audio signal. I suspect that if one should totally immerse the coil in kerosine and make it bigger than I did (mine was about two inches in diameter), with the coil length equal to the diameter one might have more luck. Maybe my problem was that my living room is probably quite inhomogeneous in field intensity--I never even thought about that. These gadgets also tend to use a lot of watts to align the proton spins, so there is probably is no pocket version. I think there must be some simple way to continuously energize the protons and then lock onto the weak continuous signal just above the noise level with a phase locked loop, which would be much more elegant from an instrumentationist's point of view and probably also more accurate. I have energized what amount to tuning forks for entirely differnt applications in this way and I feel certain the results are much preferable to hitting the thing and then listening to it ring down while trying to get a fix on the frequency. But I have always been somewhat inhibited in this quest by my supposition that one really needs two of these things to get meaningful results in most portable applications since the signal will so sensitive to orientation in the earth's field. An interesting use of a procession magnetometer might be as a very sensitive way to contineously and sensitively monitor slight variations in the earth field from a fixed outdoor location. Also don't forget that Erich Kern, who is on this list, can get you little Speake fluxgate magnetometers (about the size of a small lipstick case) for a pretty reasonable price (on the order of $50), and these probably have lots of practical applications to compensate for their slightly lower sensitivity. And just incidently the next issue of the Society for Amateur Scientist's Bulletin will have a Science Hacker column I wrote on how to build cheap little torsion magnetometers sensitive enough to see the earth's magnetic field micropulsations of a few gamma or nanotesla -- which ain't half bad, IMHO. --Yours, Roger Baker _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: [Fwd: Re: Solar winds] Date: Thu, 12 Mar 1998 09:10:07 -0700 Ok, here is the last post on the solar wind, I promise. I e-mailed one of the solar observators about the recent increase in solar wind and got this response: -- ---/---- Charles P. Watson Seismo-Watch From: John Hernlund Subject: Re: Piezoelectric cable as simple seismograph? Date: Thu, 12 Mar 1998 11:03:38 -0700 (MST) On Thu, 12 Mar 1998, prewar wrote: > I wonder if a length of this could form any basis for a simple seismo?? > A length either buried/concreted in ground, or bent to form a flexible > loop > between ground and vert/hor seismo beams ?? If one used it as the > suspension > wire for a horizontal beam, one could pick up vert. component between > frame and mass ? Have 2 seismos for the price of ONE ??? Albert, I have been looking into piezoelectric transducers for seismograph (accelerometer really) use but have never come across any references to this cable. I would be interested in looking at some; any idea where it could be found? ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ http://www.public.asu.edu/~hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: ERICH777 Subject: event precurser Date: Thu, 12 Mar 1998 13:38:08 EST n a message dated 98-03-11 21:36:34 EST, frankcnd@.......... writes: << I detected a geo-magnetic field disturbance of significant importance in the area near Fontana, CA. It lasted for approximately 4 hours and subsided by the afternoon. >> I have been given the understanding one needs at least two geo-magnetic devices some distance apart to reduce background noise to a mininum. Do you have that capability? George _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: piezocable article Date: Thu, 12 Mar 1998 19:09:50 +0000 Hi John and Meredith, You both asked about suppliers etc. for piezoelectric sensor cable......bear in mind that suppliers here in GB may not have any outlets in USA etc. Cable here is marketed by, ORMAL Ltd. FAX No 01793 484344 Tel. No 01793 484343. (This is in GB, so country code to be added.) Trade name for this cable is, VIBETEC 13, and this grade is the most sensitive which they sell. Another supplier here is, Electromail, but again I'm not sure if they have any connections in USA? I have just writen to Ormal requesting tech. spec. etc. so I will post more when I receive it, altho' I'm sure that there MUST be many outlets in USA where this cable is obtainable from.........perhaps anyone in USA etc. who has this info can post it on PSN for your info? Regards, Albert Noble (England). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: Proton Precession Magnetometer-Construction Questions Date: Thu, 12 Mar 1998 12:44:22 -0600 Roger, There is, from my web searching on magnetometers I ran across the Overhauser Effect. check out http://www.ultramag.com/overhaus.htm for a simple explanation. It sounds like this method may be a bit too complicated for a simple homebrew instrument. Jim Hannon rcbaker@............. on 03/12/98 10:42:53 AM Please respond to psn-l@............. To: psn-l@............. cc: (bcc: James M Hannon/CedarRapids/Collins/Rockwell) Subject: Re: Proton Precession Magnetometer-Construction Questions Friends, I think there must be some simple way to continuously energize the protons and then lock onto the weak continuous signal just above the noise level with a phase locked loop, which would be much more elegant from an instrumentationist's point of view and probably also more accurate. --Yours, Roger Baker _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Doug Crice Subject: Re: Proton Precession Magnetometer-Construction Questions Date: Thu, 12 Mar 1998 09:32:37 -0800 Roger--some magnetometer notes 1. You do use a phase lock loop which has two functions: to amplify and filter a very small noisy signal, and to multiply the frequency high enough for a normal counter to measure the frequency with enough resolution to get down below 1 nT (or 1 gamma) resolution. 2. Direction is not an issue. A protom magnetomer makes a scaler measurement of the total field. There are some orientation issues related to speed of collapse of the precession signal, but the field numbers don't change with orientation. 3. Some do run on batteries. The most successful example being the Geometrics G-816 which ran on 8 heavy duty D-cells for a day in the field of intermittent readings. About 5000 of the G-816 were sold and it was cloned by over 10 other companies worldwide. 4. I have never wound a coil, but have seen some with coils about 2 inches cube. There's always two coils aligned so as to cancel external fields, but sensitive proton mags don't normally work indoors at all. You have to take the sensor outside. We made a really good magnetometer once that was noisy all day except for a quiet period from about 2 to 6 AM. Turns out that was when BART shut down their DC trains. When we took it out in the ocean, we were able to measure the magnetic field caused by sea swells (a conductor) moving up and down in the earth's field. Sometimes basic science slows you down for quite a while when you run into a previously little-known phenomena that you think is instrument noise. 5. Fluxgate magnetometers can be made about as sensitive as proton magnetometers, but they are directional. The accuracy is not much, but resolution can be good, so they do get used for observatory recording. Proton mags are an absolute standard (isn't physics remarkable) except for whatever remnant magnetisim is left in the mechanism. If you're in the business, finding clean copper (no iron) is nearlyh as much trouble as finding good wire for zero-length springs. -- 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: "James M Hannon" Subject: Re: LCD's Date: Thu, 12 Mar 1998 13:03:34 -0600 Barry, Your display is very likely constructed the way you describe. It shouldn't be too hard to trace out the connections by stimulating the pins and seeing which display segment comes on. One thing you need to know is that normally LCD's are driven by an AC signal. This is true even for non multiplexed displays like yours. It prevents the display from being damaged by the DC currents. Jim Hannon gbl@....... on 03/10/98 08:57:57 PM Please respond to psn-l@............. To: psn-l@............. cc: (bcc: James M Hannon/CedarRapids/Collins/Rockwell) Subject: LCD's Hi All I have a few LCD chips. The one I am currently looking at is a 7 digit LCD in a 50 pin DIP. I would like to know if any one knows the standard pinout for a digit and power. It's not an intelligent LCD display. I understand them. I hope to attach one to a processor to display a 7+ digit number. I assume there is a backplane pin and pins for each of the 7 segments. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: David Josephson Subject: Re: Proton Precession Magnetometer-Construction Questions Date: Thu, 12 Mar 1998 14:08:01 -0800 (PST) Jim Hannon writes > There is, from my web searching on magnetometers I ran across the > Overhauser Effect. check out http://www.ultramag.com/overhaus.htm for a > simple explanation. > It sounds like this method may be a bit too complicated for a simple > homebrew instrument. Overhauser is actually just as simple as a regular proton mag but depends on having some exotic chemicals in the precession fluid (probably not all that exotic, but I never learned what they were). A Geometrics engineer who knows way more than I do about these things ran across a way for continuous readings that they called the "Stoopnagle Effect" and if we can convince Ken to join this discussion, maybe he'll tell us how to do it. It would be practical for a base station mag where the field doesn't change much. Doug Crice has already addressed most of the other things I was going to say. You'll get a signal above the noise if and only if the inductance of the coil is resonated with a low loss capacitor to roughly the Larmor frequency, and you have bucked out the local powerline field, and your preamp is quiet enough that you can see the resistance noise of the wire in the coil. And then, you typically get a signal to noise ratio of a few dB. The principle advantage of the proton mag is that it's an absolute measurement as Doug explains, and nondirectional. But in order to get good signal, all of the precessing protons in the sensor fluid must be going at the same rate, which means that the field must be uniform, which particularly means that all the stuff in the sensor must be nonmagnetic. Regular enameled copper wire will work okay for a sensor of 1 or 2 nT sensitivity, but it's got to be much cleaner if you want enough signal for better sensitivity than that. -- David Josephson / Josephson Engineering / San Jose CA / david@............. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: David Josephson Subject: Re: Proton Precession Magnetometer-Construction Questions Date: Thu, 12 Mar 1998 14:16:24 -0800 (PST) The page Jim Hannon found > There is, from my web searching on magnetometers I ran across the > Overhauser Effect. check out http://www.ultramag.com/overhaus.htm for a > simple explanation. is an excellent description as far as it goes for both free proton and Overhauser mags. Ivan's patent has also expired now, so you might want to look it up and see how to do it. -- David Josephson / Josephson Engineering / San Jose CA / david@............. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: joe irvine Subject: zero length spring Date: Thu, 12 Mar 1998 15:44:30 -0800 Probably everything one would want to know about the zero length spring can be found at http://www.lacosteromberg.com/uwman3a.html#zero I happened to be a student along with Lacoste at the Univ. of Texas in the early 1930's when Dr. Romberg (physics professor) posed the question to Lacoste, who was a brilliant student besides being a top ten tennis player, which led to the zero length spring and a gravity measuring device which would measure the difference in gravity if it were raised 1 foot! Unlike the old torsion balance it could be read immediately. Under Dr. Romberg's supervision I built a horizontal pendulum seismograph with a 400# weight. It performed nicely writing with mechanical magnigication on a drum wound with smoked paper. If you just go to the web site www.lacroseromberg.com/ there is available a lot of interesting information. Joe _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: Proton Precession Magnetometer-Construction Questions Date: Thu, 12 Mar 1998 16:11:15 -0800 Interesting stuff. I looked up the patent and it is: 3966409 : Nuclear magnetometers for earth's field measurements based on dynamic polarization of nuclei and free radical substance for use therein Its available in its entirety on the IBM patent site. Charles R. Patton _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: event precurser Date: Thu, 12 Mar 1998 20:57:17 -0800 (PST) >n a message dated 98-03-11 21:36:34 EST, frankcnd@.......... writes: > ><< I detected a geo-magnetic field disturbance of significant importance in >the > area near Fontana, CA. It lasted for approximately 4 hours and subsided by > the afternoon. >> > >I have been given the understanding one needs at least two geo-magnetic >devices some distance apart to reduce background noise to a mininum. Do you >have that capability? > >George > > Hi George: No... I don't have noise canceling ability. Instead, I use filtering to a very narrow band from 0-5 Hz with lots of dampening. When I see that meter pinging around then I know something is in the wind over here. It smooths out all of the transient noise in the background. Also, all of the instrumentation is located inside of a practically free of terrestrial noise lab. Best Regards, Frank Condon mailto:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" _____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Al Allworth" Subject: Re: USBR Server Date: Thu, 12 Mar 1998 21:26:10 -0800 -----Original Message----- From: Dewayne Hill To: psn-l@............. Date: Thursday, March 12, 1998 7:50 AM Subject: USBR Server >Can anyone reach URL "www.seismo.usbr.gov"? I can't get there from here. > >Dewayne (n0ssy) & Linda (n0uqf) Hill I tried it and couldn't get it to work either. I did a trace-route on it and found the url to be OK. The trace went all the way through, so its working but just not answering. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Redlands M4.5 Map! Date: Thu, 12 Mar 1998 21:50:03 -0800 (PST) hhello all: Here is the URL for a map that shows the Fontana Trend cross-section and the last couple of magnitude 4 plus earthquakes, including the latest M4.5 "Crafton Hills" earthquake. http://www.trinet.org/eqreports/thismonth/reds98.html Frank Condon mailto:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Redlands M4.5 Map! Date: Thu, 12 Mar 1998 22:01:41 -0800 (PST) Oops! I gave out the wrong URL for the map that I mentioned. Here is the correct map for the description: http://www.scecdc.scec.org/crafton98.html Frank Condon mailto:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" >-------------------------------------------------------------------------- >Your following message has been delivered to the 268 members of > the list psn-l@............. at 21:46:38 on 12 Mar 1998. >-------------------------------------------------------------------------- > > > >hhello all: >Here is the URL for a map that shows the Fontana Trend cross-section and the >last couple of magnitude 4 plus earthquakes, including the latest M4.5 >"Crafton Hills" earthquake. > >http://www.trinet.org/eqreports/thismonth/reds98.html > >Frank Condon >mailto:frankcnd@.......... >"Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Francesco" Subject: ITALIAN-BALKAN BORDER REGION MEDIUM QUAKE Date: Fri, 13 Mar 1998 17:34:02 +0100 15.15 UTC Mb 4.5 Preliminary location: 30 km Est from Trieste (Italy); italian/balkan = border region Francesco Nucera - Osimo, Italy - Lat. 43.290 N Long 13.292 E

15.15 UTC
Mb 4.5
Preliminary location: 30 km Est from = Trieste=20 (Italy); italian/balkan border region
 
 
 
Francesco Nucera
- Osimo,  Italy  = -
Lat. 43.290 N  Long 13.292=20 E
From: "Charles R. Patton" Subject: Re: piezocable article Date: Fri, 13 Mar 1998 08:48:49 -0800 Below I give all the information on piezoelectric cable source (the manufacturer of it.) But right here I would like to make a suggestion on how to get around the use of the hard-to-get special cable. Buy any standard foam core coax cable such as 75 ohm cable TV coax. Impress on the center conductor a very high voltage from a very large resistor, i.e., perhaps a 1000 volts through a 100 Megohms. Use a good quality coupling capacitor, such as a .001 uF 2 KV, from the center conductor to your amplifier. You might also want to do some surge protection on the front end of your amplifier in case the capacitor breaks down! You now have an extremely microphonic cable setup that will rival the piezoelectric cable. I've never done this, but it should work very well. Let me know if you do try it. Anyway for the original question: The manufacturer of the piezoelectric cable is AMP, Inc. in the United States and may be the source for the cable in other countries as well. They are very big in the manufacture of piezoelectric devices using Kynar. If you go to this URL you will be on the sensor page which points at their contact numbers and has an application note as well. http://www.amp.com/sensors/sensors.html Contacting AMP Sensors Americas Glen MacGibbon P.O. Box 799 Valley Forge, PA 19482 Tel: 610 650-1500 FAX: 610 650-1509 Email: sensors@....... Pete Smith 172 Big Valley Road Folsom, CA 95630 Tel: 916 983-8644 FAX: 916 983-0479 Email: prsmith@....... Europe Richard Brown AMP Deutschland GmbH Carl Benz Str 12-14 64625 Bensheim Germany Tel: 49 6251 133 415 FAX: 49 6251 133 472 Email: rbrown@....... When corresponding by email, please include your full name, company name, complete mailing address, and telephone number. They tend not to do well with small orders as they are oriented to the big OEM type accounts. But I have dealt with Pete Smith, and he has always been helpful to me. Good luck, Charles R. Patton, Editor, Geo-Monitor _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: piezocable article Date: Fri, 13 Mar 1998 22:46:49 +0000 Charles R. Patton wrote: > Below I give all the information on piezoelectric cable source (the > manufacturer of it.) But right here I would like to make a suggestion > on how to get around the use of the hard-to-get special cable. Buy any > standard foam core coax cable such as 75 ohm cable TV coax. Impress on > the center conductor a very high voltage from a very large resistor, > i.e., perhaps a 1000 volts through a 100 Megohms. Use a good quality > coupling capacitor, such as a .001 uF 2 KV, from the center conductor > to your amplifier. .....................snip. Hi Charles, Well, as I am contemplating, one day, in maybe burying 100yds of 2 core + earth ring main cable in the form of a 70ft. square, (forming a 3 turn loop), to see what magnetic influences I may detect here in GB, I could at the same time put 100yd of coax alongside it to see what it may also detect, vibration wise. Would have to have a very stable 1000v tho', else mag, detection may be overwhelmed by possible induction from coax. Your coax plan is very much cheaper than piezoelectric cable at $24 per yd! Thanks for interesting and unusual info. Regards, Albert Noble (England) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: curtis Subject: magnetic field detection schematic & parts list Date: Fri, 13 Mar 1998 17:59:03 -0800 (fwiw) April 1998 issue of "Worldradio" page 69 - design by Rudi, HB9DU. (comment) - somewhat 'toy-like' but interesting. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Francesco" Subject: BIG QUAKE IN ANATOLIC AREA Date: Sat, 14 Mar 1998 22:02:37 +0100 I'm reciving still now a big quake from Anatolic Area (Iran-Turkey) Preliminary: UTC 19.40 org Ms => 6.2 Located: Iran As soon as possible I'will post the file. Anyone had registered the event? Francesco Nucera - Osimo, Italy - _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "John Krempasky" Subject: Re: BIG QUAKE IN ANATOLIC AREA Date: Sat, 14 Mar 1998 17:14:17 -0500 NEIC has it as a 6.9 in Southeastern Iran; (Labeled as "Northern Iran" in the various lists but on all the maps I see it's in the S.E. of Iran.). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Seisguy Subject: Fwd: Strong Earthquake Reported in Iran Date: Sat, 14 Mar 1998 17:23:08 EST Here's what you have recorded. Mike O'Bleness Northridge, CA Strong Earthquake Reported in Iran ..c The Associated Press WASHINGTON (AP) - A strong earthquake was recorded Saturday afternoon in Iran by the U.S. Geological Survey. Spokeswoman Kathleen Gohn said the preliminary magnitude of the quake was 6.9, typically strong enough to cause death, injury and serious damage. However, she said the government agency had no immediate reports of damage caused by the quake, which occurred at 2:41 p.m. EST, or 11:11 p.m. local time. She said the epicenter was about 35 miles east-southeast of Kerman, a city with a population of about 250,000, and about 520 miles southeast of Teheran. AP-NY-03-14-98 1657EST Copyright 1997 The Associated Press. The information contained in the AP news report may not be published, broadcast, rewritten or otherwise distributed without prior written authority of The Associated Press. To edit your profile, go to keyword NewsProfiles. For all of today's news, go to keyword News. From: frankcnd@.......... (Frank Condon) Subject: Seismic Prediction Group Date: Sat, 14 Mar 1998 20:29:23 -0800 (PST) Hello All: Here is an interesting URL for a group that is interested in predicting earthquakes. http://www.btinternet.com/~seismoprediction/ Frank Condon mailto:frankcnd@.......... "Located in the seismic corridor somewhere between fontana & Mammoth Lakes" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: Seismic Prediction Group Date: Sun, 15 Mar 1998 12:04:10 -0700 (MST) On Sat, 14 Mar 1998, Frank Condon wrote: > Hello All: > Here is an interesting URL for a group that is interested in predicting > earthquakes. > > http://www.btinternet.com/~seismoprediction/ > > Frank Condon > mailto:frankcnd@.......... > "Located in the seismic corridor somewhere between fontana & Mammoth Lakes" I see a lot of this kind of stuff on the internet. I have yet to see one that is even remotely credible, but I would love to hear some of the views held by our USGS benefactors on this subject... In other words, is there a good scientific earthquake prediction study under way somewhere, or is it all quackery??? ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ http://www.public.asu.edu/~hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen & Kathy Subject: Re: Seismic Prediction Group Date: Sun, 15 Mar 1998 12:17:03 -0800 > I see a lot of this kind of stuff on the internet. I have yet to see > one that is even remotely credible, but I would love to hear some of the > views held by our USGS benefactors on this subject... In other words, is > there a good scientific earthquake prediction study under way somewhere, > or is it all quackery??? > > ****************************************************************************** > > John Hernlund > E-mail: hernlund@....... > WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ > http://www.public.asu.edu/~hernlund/ Hmmmmmmm, Quackery is not a very scientific term and is usually associated with the medical profession. I'm not sure how you would fraudulently stimulate an earthquake in your favor but even the USGS makes earthquake perdictions, are you saying the USGS is not credible?? By the way, what is their hit record? Some how I think I do feel cheated. All this time I thought all this money and time that I and the government was spending on EQ study was to find the weaknesses and precursors to deadly EQs. I noticed that some hoaky things have turned out to be pretty interesting science when the old generation dies off! Take radio for one, take the airplane for another, etc. etc. It is at the edge of life where all new discoveries are made! SKM (Stephen) Pilot Hill Ca. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Pinpoint Earthquake News Subject: Re: Seismic Prediction Group Date: Sun, 15 Mar 1998 12:28:39 -0800 (PST) On Sun, 15 Mar 1998, John Hernlund wrote: > > On Sat, 14 Mar 1998, Frank Condon wrote: > > http://www.btinternet.com/~seismoprediction/ > > I see a lot of this kind of stuff on the internet. I have yet to see > one that is even remotely credible, but I would love to hear some of the > views held by our USGS benefactors on this subject... In other words, is > there a good scientific earthquake prediction study under way somewhere, > or is it all quackery??? You obviously did not visit this site as I did and saw that it was a scientific and medical venture as opposed Dr. Turi etc...etal....Just because someone has an idea and is willing to throw it out for testing and public scrutiny does not make them a quack....conversely the USGS are NOT *my* benefactors, although they may devote space, time advice to PSN; They have also given me plenty of *credible* and worthy advice over the years - yet I as Larry does, and as Ben Parks does and many others, finance our own work and take credit for success and hits for failures. Bob Shannon Pinpoint EQ Newsletter _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: piezocable article Date: Sun, 15 Mar 1998 12:39:35 -0800 Well I tried out my scheme with the coax cable last night -- doesn't work (or at least at 50 V with 150 Meg feed resistor.) The triboelectric effect of the un- power supply assisted cable is just as large. I got about 15 mV when tapping with a pencil and maybe 5 mV when bending and slapping the cable. So back to the drawing board. I want to mention though, that piezoelectric effects are hard to use at the lower frequencies of seismic interest because of the need for extremely high input impedance of the amplifier in order to get to lower frequency response. >>> a quote from my note of 8/17/97 to the PSN list:>>>> Re: Piezo accelerometers for seismic work. Highly unlikely. I have used extensively piezo-ceramic accelerometers of approximately the size in the web site (http://www.oceana.inter.net) illustration (cantilever beam types in SMT 1206 like packages from TDK, Murata, and others.) All of these have sensitivities of around 1 to 2 mV /g. They have typical capacities of around 200 pF. So in order to bias the front end preamp you have to parallel them with resistors of 10 M or more. This then sets the low frequency rolloff, i.e.: f = 1 / (2PiRC) = 1/(6.28*200e-12*1e7)=79.6 Hz So you have an extremely high cutoff problem first of all. Couple that with the fact you've got the 10 M resistor generating a noise voltage of approximately 300+ nV, you are left with a minimum sensitivity of only g*300nV/1mV=300 ug at 80Hz and falling from there. If you want to fight the problem of the resistor versus cutoff frequency the noise will only go up. So you're kind of in a catch 22. I don't anticipate that this is a good approach. >>>>>>>>>>>>>> The above was a comment on single accelerometer type things, but also applies to piezocable. The only difference is that with enough length, the capacitance of the cable could be high enough to allow lower input impedances -- but it would have to be installed such that it responds as a total to the seismic wave, i.e., broadside to the propagation direction, but I'm not sure that the cable is a pressure sensor, it may only sense shear. If so, the broadside direction would be insensitive. The reason I mention the pressure problem is that when the Kynar is made for hydrophone use, it's sandwiched with aluminum coupons to cause a conversion from pressure to shear in the material in order to gain sensitivity. Charles R. Patton patton@......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: Seismic Prediction Group Date: Sun, 15 Mar 1998 15:25:24 -0700 (MST) On Sun, 15 Mar 1998, Stephen & Kathy wrote: > Hmmmmmmm, Quackery is not a very scientific term and is usually > associated with the medical profession. I'm not sure how you would > fraudulently stimulate an earthquake in your favor but even the USGS > makes earthquake perdictions, are you saying the USGS is not > credible?? By the way, what is their hit record? > Some how I think I do feel cheated. All this time I thought all this > money and time that I and the government was spending on EQ study > was to find the weaknesses and precursors to deadly EQs. > I noticed that some hoaky things have turned out to be pretty > interesting science when the old generation dies off! Take radio > for one, take the airplane for another, etc. etc. > It is at the edge of life where all new discoveries are made! > SKM (Stephen) > Pilot Hill Ca. Then perhaps you may have seen something I have not. Sure, quackery is a strong word, too strong I suppose. Please tell me what you know about these projects... ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ http://www.public.asu.edu/~hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: Seismic Prediction Group Date: Sun, 15 Mar 1998 15:36:28 -0700 (MST) On Sun, 15 Mar 1998, Pinpoint Earthquake News wrote: > You obviously did not visit this site as I did and saw that it was a > scientific and medical venture as opposed Dr. Turi etc...etal....Just > because someone has an idea and is willing to throw it out for testing and > public scrutiny does not make them a quack....conversely the USGS are NOT *my* > benefactors, although they may devote space, time advice to PSN; They have > also given me plenty of *credible* and worthy advice over the years - yet > I as Larry does, and as Ben Parks does and many others, finance our own > work and take credit for success and hits for failures. > Bob Shannon > Pinpoint EQ Newsletter Wow, I guess my language was somehow offensive! It was not meant to be that way, and the benefactor term is not meant in a financial or practical sense. What I meant was that it seems that there are some USGS people who have been working very hard to share the PSN with their fellow seismologists working in the profession. They are not responsible for the success or failure of the PSN at all. And I did visit the site, and thought it was quite interesting, and I certainly hope they are successful with their approach. I do remain skeptical however, because of the mechanisms producing earthquakes. Whole regions are strained over long periods of time and something just breaks... This makes it awfully hard to gauge when a quake will occur. Perhaps barometric pressure even influences the onset of quakes but it is hard to tell. Maybe a fly landing near the fault will be the straw that breaks the camel's back. Anyways, my original question could probably be better worded by asking if anyone could direct me to some good information about great techniques or studies underway for quake prediction. Everything I have seen is really wild, and I am not aware that the USGS is doing this type of study. If they are, I am interested in finding out more information about this topic... ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ http://www.public.asu.edu/~hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Seismic Prediction Group Date: Sun, 15 Mar 1998 15:56:33 -0800 (PST) > Wow, I guess my language was somehow offensive! It was not meant to >be that way, and the benefactor term is not meant in a financial or >practical sense. What I meant was that it seems that there are some USGS >people who have been working very hard to share the PSN with their fellow >seismologists working in the profession. They are not responsible for >the success or failure of the PSN at all. > And I did visit the site, and thought it was quite interesting, and I >certainly hope they are successful with their approach. I do remain >skeptical however, because of the mechanisms producing earthquakes. >Whole regions are strained over long periods of time and something just >breaks... This makes it awfully hard to gauge when a quake will occur. >Perhaps barometric pressure even influences the onset of quakes but it is >hard to tell. Maybe a fly landing near the fault will be the straw that >breaks the camel's back. > Anyways, my original question could probably be better worded by >asking if anyone could direct me to some good information about great >techniques or studies underway for quake prediction. Everything I have >seen is really wild, and I am not aware that the USGS is doing this type >of study. If they are, I am interested in finding out more information >about this topic... > >****************************************************************************** > > John Hernlund > E-mail: hernlund@....... > WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ > http://www.public.asu.edu/~hernlund/ > >****************************************************************************** > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > Hi John: I found this information in the FAQ located at: http://eci.ucsb.edu/~asb/quakefaq.html ----------------------------------------------- GEOELECTRIC SIGNALS: DO THEY PRECEDE EARTHQUAKES? Speaking at the recent meeting of the American Geophysical Union, Anthony Fraser Smith of Stanford (415-723- 3687) reviewed his data from four years ago which showed that local measurements of Earth's magnetic field fluctuated much more vigorously than usual in the days and hours before the 7.1-magnitude Loma Prieta earthquake. Many scientists hesitate to infer any correction between the signals and the quake, particularly on the basis of only one such data set. To study the matter further, Fraser Smith has set up several detectors around California near faults. Simon Klemperer, also of Stanford (415-723-7344), attempts to model Fraser Smith's signals by suggesting that in the buildup to a quake, a flexing fault system might squeeze pockets of water together (which are sparse at these depths--18 km), altering the electrical conductivity of the fault, which in turn can act like an antenna to modulate the measured magnetic field at the surface. Other types of geoelectric signals possibly related to quakes were reported at the AGU meeting. Seiya Uyeda of Tokai University in Japan and Texas A&M cited data linking four recent earthquakes in Japan with anomalies in the static voltage differences between various measurement stations. Jean Chu of MIT presented a small portion of an extensive Chinese study (over 20 years) of earthquakes and possible precursors in the form of changes in the conductivity of the Earth. ----------------------------------------------------- Frank Condon mailto:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Stephen & Kathy Subject: Re: Seismic Prediction Group Date: Sun, 15 Mar 1998 20:22:59 -0800 John Hernlund wrote: > > Then perhaps you may have seen something I have not. Sure, quackery > is a strong word, too strong I suppose. Please tell me what you know > about these projects... > > ****************************************************************************** > > John Hernlund > E-mail: hernlund@....... > WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ > http://www.public.asu.edu/~hernlund/ My points are these: 1st. It is not good science to get involved with debunking things which can not be proved,,,, "today". Other wise you get lumped with those who didn't, at first, buy into the duck-bill-platypus or the high temperature of venus or the usefulness of the radio or airplane. I feel a lot worse for the ignorance of the debunkers than I do for the miscalculations or failures or ignorance of the debunkees! 2nd. If past history is any indication, then the greater scientific view would be to be open minded. Take a closer look at systems that have a greater than 50% success rate and then find a scientific process to discover the mechanism. When success is greater than 50% it could be important!!! I'm aware of only 3 mechanisms that can raise the success rate above 50%. It's either fixed before hand, skewed after or it is real! I'm not sure how you would pre-fix an earthquake, so for me that only leaves 2. Perhaps a good statistician could settle the question??? I would be very interested to see their results. 3rd. What would be a refreshing change would be to see the scientific community take an interest in these "prediction annomolies" and see if they can provide scientific tools and talent to discover their validity and see if there is any way that it can be used to save lives! I notice that the weather man doesn't always get it right and now-a- days they have some pretty sophisticated tools. As for specifics: Impo Faber had an interesting site but unfortunatly no one seemed to take a scientific interest so that information may be lost! How will we ever know if it was real or not, or how many lives might have been affected. Maybe it was a trick, but maybe not! I monitor any of the sites that I become aware of and that don't charge. Because of my interest in EQs I am very interested in, and open minded to, any indications that will give a precursor. If that includes someone getting ill, let's find out why! If there is more than one way to listen to the earth, let's discover how! Less than 100% does not prove failure any more than greater than 50% proves success! Until the mechanism is discoverd, ignorance prevails in both! Throwing the baby out with the wash has been the embarrassment of many a scientist! The ignorant have an excuse! I apologize if this was a waste of band width. But I do feel that there are some very sincere people trying to contribue significant data. I don't know if any of their data will prove useful, someday, in our quality of life but until it is proved otherwise I don't plan to hold my breath and I do intend to keep an open mind! I think history has shown that science has done a very good job of trapping itself, many times in its own debunkery! SKM Pilot Hill Ca. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roger Baker Subject: Seismic Prediction Date: Sun, 15 Mar 1998 23:13:20 -0600 Friends, Here is how seismic prediction seems to me as a non-professional. I would appreciate a correction if I'm known to be far off base. It seems to me that if time could somehow be speeded up enormously, by a factor of a million say, that we could potentially gather enough data to make fairly good statistical predictions of the typical earthquake patterns in any one area. Not having this practical option, the next best thing is to try to model the physical causes of earthquakes in an area, plus take lots of measurements from lots of stations in order to attempt to magnify the predictive usefulness of the very meager data stream available from these naturally rare events. All this being the case, it is not really known to what degree typical earthquake activity can be predicted until a larger well-standardized data base is accumulated over a considerable length of time, in order to verify the predictive usefulness of any given seismic interpretation. One would suppose that earthquakes in some areas might be more inherently regular and predictable than others in accord with their exact physical causes. --Yours, Roger _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Seismic Prediction Group Date: Sun, 15 Mar 1998 23:00:15 -0700 Pretty nice exchange about earthquake prediction on the PSN-L. As one in the media so much with my Seismo-Watch earthquake graphics, I tend to receive quite the barrage of people who claim to be able to predict earthquake activity. Many have devoted large portions of their life to trying to find the elusive Golden Challis. Some have been quite clever, others appear to be close, none have been right on target all the time In one of the links from the Seismic Prediction Group web page, I ran across a quote from Charles F. Richter who said in 1964 that "Claims to predict [earthquakes] usually come from cranks, publicity seekers, or people who pretend to foresee the future in general." Unfortunately, this is still the consensus of the scientific community today. But it is the scrutiny from our peers which validate new theories. We would not be scientists if we did not question every Tom, Dick or Jane which came along and said "The world is round", let alone "I can predict earthquakes". Show me how it works, then show me again, and again. Frankly, Richter's point is one to consider, for those who use a public forum to test a working theory may only be looking for their 10 seconds of fame, and not the Golden Challis. I know of no scientist who shouts "Eureka, I found it!" without first testing and retesting to make sure he/she is right. Public humility is painful to the scientist, often a death sentence. But those who are not scientists and do not listen to their peers, thier remarks just blow away with the winds of time. So, my hat is off to Richter, Heaton, Jackson, Stark, McEvilly, and the like, who pry at every nook and cranny of every prediction theory, testing for even a slight weakness in the framework. It is their job, and by God, we need people like them; science demands it! However, if one could be 95% right in predicting when and where a major earthquake were to occur, would this be of value to civilization? What if the proposition were to be 90% correct, could this be implemented to save lives, damn the scientific absolute? How wide could we open the "seismic window" and still have it be a useful tool for emergency preparedness before it compromises people's lives as more of a bother or just another cry of "Wolf!"? Think of the expense if an alarm were to be sounded and nothing were to happen. But have we lost sight of what the Golden Challis really is? It's about saving lives from earthquakes. Reducing the death and suffering from the unexpected temblor. That's the goal! Even a sip from the Challis is worthy of a life time of perseverance because that means whatever you did saved someone's life. I applaud those who venture on the quest of the Golden Challis and embrace those that even get close. They provide the stepping stones for the next person, and the next, and the next, until we as a society say we are close enough to take action when the need arises, when openning that seismic window means saving lives. As long as there is a chance to save even one life, my door is always open. And, I am a scientist [so don't let it hit you in the rear on the way out]. ---/---- 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: Doug Crice Subject: Re: Seismic Prediction Date: Mon, 16 Mar 1998 06:02:56 -0800 I can't stand to stay out of the earthquake prediction debate any longer. If you read my earlier thread on Geodimeter fault movement measurements, you know that I dabbled in earthquake prediction in the 1960's, when I was much younger and even more foolish. You may recall that one prediction that I got wrong was appropriated by my boss for an announcement at the AGU meeting and it cost him his job. EQ prediction was really incorrect then. We didn't have much data back then, and it was a hit or miss proposition, and the program was cancelled. The USGS began a similar program with different geometries, and found nothing but a lot of fault movement. The scientist who adopted it gave several papers on how the measurements had failed to predict earthquakes. I did successfully predict the Corralitos earthquake in the 1960s, using some rather odd gyrations of Mount Loma Prieta. However, the USGS has been doing some serious research on earthquake prediction. I heard that they managed to appropriate a bunch of money from Congress with the promise of success. Their most visible prediction of the Parkfield Earthquake was a failure, and the negative publicity resulted in budget cuts. Interestingly enough, the USGS geodimeter guy wrote a paper where he suggested that the 1989 Loma Prieta earthquake might have been predicted in his data (using hindsight, nothing wrong with that). I looked at his data, and it does predict the earthquake the same way my data did in the 1960's, but not the way his paper describes it. He looks as long-term averages. I looked at short-term pertubations, and there's a fat one right in the data prior to the earthquake. Is this stuff real? Who knows? The problem is getting enough data of whatever is the right kind in the right place to catch an earthquake. Nobody disputes that we can predict volcano eruptions well enough to move people out of the way. It's easy to predict landslides if you instrument them. Both these are long-term natural processes, why should earthquakes be any different? - 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: Seismic Prediction Date: Mon, 16 Mar 1998 07:58:32 -0700 Er, ah...make that chalice, not challis. Oh, bother... -- ---/---- Charles P. Watson Seismo-Watch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: W6JRF Subject: Re: Seismic Prediction Date: Mon, 16 Mar 1998 12:03:06 EST Knot 2 werri, wee knew watt yew ment. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: piezocable article Date: Mon, 16 Mar 1998 18:33:52 +0000 Charles R. Patton wrote: > Well I tried out my scheme with the coax cable last night -- doesn't > work (or at least at 50 V with 150 Meg feed resistor.) The > triboelectric effect of the un- power supply assisted cable is just as > large. I got about 15 mV when tapping with a pencil and maybe 5 mV when > bending and slapping the cable. So back to the drawing board... ........... > the capacitance of the cable could be high enough to allow lower input > impedances -- but it would have to be installed such that it responds as > a total to the seismic wave, i.e., broadside to the propagation > direction, but I'm not sure that the cable is a pressure sensor, it may > only sense shear. Hi Charles and everyone, This all looks like a non starter....burying 100 yds of cable in any orientation would be lacking some inertial comparative mass alongside it anyway. Unless cable were 1/2 wavelength + long, it wouldn't be subjected to any movement, which would generate any volts. (Whole length moving together as one within earth around it.) The article I read was about sound pick up, but I just wondered about a simple seismo possibility...... That 1/2 wave length is not practical of course. I was considering running it alongside 2core + earth loop as experiment, but maybe not after what you say. Regards, Albert Noble (England). > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Ted Blank Subject: section.gif file Date: Mon, 16 Mar 1998 11:36:06 -0800 (PST) I was unable to access the site referenced in Edward's note, but I detached the file and placed it in my public ftp directory on ftp.netcom.com. You can use anonymous ftp, ch then cd to /pub/tb/tblank and download (in binary) section.gif. The image is a little coarse (about 500 by 300 pixels) but very recognizable. If anyone has access to the original and could scan it at higher resoulution I will be glad to put it up for ftp. Maybe Larry wants to put it on the web site too? Feel free... Regards, Ted _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: Seismic Prediction Date: Mon, 16 Mar 1998 19:49:54 +0000 Roger Baker wrote: > > > It seems to me that if time could somehow be speeded up enormously, by a > factor of a million say, that we could potentially gather enough data to > make fairly good statistical predictions of the typical earthquake patterns > in any one area. > > Not having this practical option, the next best thing is to try to model > the physical causes of earthquakes in an area, plus take lots of > measurements from lots of stations in order to attempt to magnify the > predictive usefulness of the very meager data stream available from these > naturally rare events. Hi, If one rubs a finger across a rubber balloon, or opens a creaking door very slowly, the continueing slipping/locking/slipping/locking can be heard which doesn't follow predictable cycles or patterns..... (depends on finger/rubber and steel door hinge to wood friction at any one point.) This slippage/locking is what we would hear if only one could speed up earthquake data a millionfold or such. Altho' my analogy is a fast slip/lock/slip system it is still difficult to predict. So how much harder with 'quakes, where systems are exposed to outside unpredictable influences as well. The MOST dangerous 'quakes don't always send out invitation cards in the form of magnetic/electric field/animal behaviour/radon gas emission etc. etc. either. Regards. Albert Noble (England). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Taber Subject: Re: Seismic Prediction Group Date: Tue, 17 Mar 1998 10:01:16 +1200 (NZST) I think the discussion of earthquake prediction here has shown what an important (dare I say emotional) topic it is to those interested in earthquakes and their causes. There appears to be the feeling that scientists aren't interested in prediction and only want to debunk those who are trying to solve the problem. While I agree that some scientists seem to be on a crusade against prediction, I don't think that is the general view. Perhaps a little historical perspective will help put the debate in context. 20 years ago seismologists thought they almost had the prediction problem solved, due to a few successes and a vast array of new precursory phenomena that seemed to fit a model of earthquake generation (small cracks forming in the surrounding rock shortly before failure). In the past 20 years, few (or none, depending on your point of view) of the precursors have proved to be successful. After the failure of the Parkfield prediction, where a large amount of time, money and equipment had been invested for several years, most seismologists decided that the research dollars can be better spent trying to learn more about the earthquake generation process, and estimating the amplitude and frequency of damaging ground motions that may occur in a region over the lifetime of a building. If we can provide the information needed by engineers to design safer buildings, that will save lives, and decrease the destruction caused by earthquakes. Earthquake prediction research is still being carried out by scientists throughout the world. For example there is a group of statisticians and seismologists working on a variety of models here at Victoria. There is still a prediction/forecasting session at AGU meetings and there are specialist prediction conferences. An entire issue of Geophysical Research Letters (I think it was last year) was devoted to discussing the predictions of the Greek group led by Varotsos. The reason that the scientific community doesn't seem to take an interest in many of the prediction anomalies is that they have been disappointed many times before. That doesn't mean that no one should look, but just that they must accept that they will need a very good case before anyone will take notice, because there have been many individual predictions in the past that only worked once. If someone can show that they are doing consistently better than random chance, then I think the scientific community will listen. John Taber School of Earth Sciences Victoria University Wellington, New Zealand _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Doug Crice Subject: Re: Seismic Prediction Group Date: Mon, 16 Mar 1998 14:33:35 -0800 I don't have all the facts, but I'm not sure that the Parkfield prediction was a failure. I believe they predicted the earthquake on the basis of the 20-year cycle for the Parkfield EQ, plus that fact that fault displacement comes to a screeching halt right about there. They spent a small fortune instrumenting and measuring the event in order to find physical precurors of the upcoming earthquake. Ah, Mother Nature confounded them by not having the earthquake. Since it didn't happen, you really can't say that the prediction was a failure, unless you count 20 +/-10 year cycles a prediction. By the way, it's coming as sure as Murphy's Law. -- 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: Seismic Prediction Group Date: Mon, 16 Mar 1998 14:56:20 -0700 Doug Crice wrote: > > I don't have all the facts, but I'm not sure that the Parkfield > prediction was a failure. I believe they predicted the earthquake on > the basis of the 20-year cycle for the Parkfield EQ, plus that fact > that fault displacement comes to a screeching halt right about there. > They spent a small fortune instrumenting and measuring the event in > order to find physical precurors of the upcoming earthquake. > > Ah, Mother Nature confounded them by not having the earthquake. Since > it didn't happen, you really can't say that the prediction was a > failure, unless you count 20 +/-10 year cycles a prediction. By the > way, it's coming as sure as Murphy's Law. Thanks Doug, I was about to say something. The Parkfield test is still good and is a leading spot for the next M6+ quake in California. IRIS is leading a seesion this summer on the Parkield experiment. Held out of UC Santa Cruz, I believe. Sould be one to attend! -- ---/---- Charles P. Watson Seismo-Watch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: Seismic Prediction Date: Mon, 16 Mar 1998 18:58:20 -0800 Friends I agree with Roger. I think our time window is extremely limited. What I see as a practical evolving implimentation of seismic prediction is to have zones (in time and space) that define areas which have a greater and lesser probability of the occurance of a quake of a particular magnitude (not exact fault lines). The current building codes address this now to a limited extent. If people are educated in proper proceedures in case of an event (get there houses and family plans in order), governments have working (current) safety plans in case of an event, and unsafe buildings are corrected we will have made the biggest step. Since the task could be large, the above could be implimented and concentrated in the areas with greatest probablility first. I am doubtful in our lifetime that we will know ,consistently, on which hour a 7.0 event will occur, but if we are prepared for it, a big step could be made. I am a inquisitive person like most of you probably are, being interested in this "hobby", so I don't think alternative ideas wrt prediction should be ignored but they should be integrated into what we already know and a better picture developed. If we knew that a 7.0 event would occur tomorrow and we were totally unprepared would it help very much? Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: Seismic Prediction Group Date: Tue, 17 Mar 1998 09:48:39 -0800 My $.02 or so on the subject of seismologists' reticence to accept prediction claims. Probably most practicing scientists or engineers have been in the position at least once of having to change their position on something (eat their words), and that change will cost someone money. (I've been there quite a few times). If it happens too much bosses get perturbed, money gets cut off, projects cancelled, etc. This is an uncomfortable position to be in and we strive to avoid these problems when we can. And one way is to try to thoroughly test a hypothesis before investing too much in it. Because a lot of money has been spent to come up with earthquake predictions without much success, it has created a somewhat sticky situation. The public is becoming more and more sensitive to predictions that don't pan out, but at the same time there is a need to demonstrate that progress is being made to justify the money spent. Scientists are often familiar with this type of problem, because they face it all the time. I think often the answer is to demonstrate steady progress without a lot of false alarms, and great restraint is needed to avoid prematurely announcing success. But some people with a desire to predict earthquakes may not be as familiar with this fine line. I think some of what irks seismologists is less restrained earthquake predictions, especially from people the public perceives as credible. I think seismologists fear too many cries of wolf from any direction, when they are already fighting an uphill credibility battle themselves. And even more irksome is such a prediction based on a factor previously shown to be statistically unreliable, especially when there is a success or two due to probability. To scientists, it is probably pretty difficult to sit by and watch the public spend their resources because of an earthquake prediction based on something known to not work, or even something not thoroughly tested. I also think the public as a whole has a rather poor intuitive sense of probability and statistics, which very much compounds the issue. Enough rambling. I can see both sides of the problem, and generally side with those urging restraint and a lot of testing before advertising predictions. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Taber Subject: Re: Seismic Prediction Group Date: Wed, 18 Mar 1998 15:14:05 +1200 (NZST) Doug Crice wrote: >I don't have all the facts, but I'm not sure that the Parkfield >prediction was a failure. I believe they predicted the earthquake on >the basis of the 20-year cycle for the Parkfield EQ, plus that fact >that fault displacement comes to a screeching halt right about there. > >Since it didn't happen, you really can't say that the prediction was a >failure, unless you count 20 +/-10 year cycles a prediction. Charles Watson wrote: >The Parkfield test is still >good and is a leading spot for the next M6+ quake in California. IRIS is >leading a session this summer on the Parkfield experiment. I agree that they still are likely to catch the next earthquake at Parkfield, and much is being learned about earthquake processes and faulting by having a range of instrumentation in one location. Given the past record of earthquakes there, the segment is still considered to be the most likely place for magnitude 6 or greater earthquake. The Parkfield prediction (Bakun and Lindh, 1985, Science, pp 619-624) was that an earthquake would occur in 1998+/- 5 years, with a 95% probability of occurrence by 1993. Admittedly their original prediction allows a finite probability beyond 1993, so technically the prediction hasn't failed. A recent USGS press release called it "unfulfilled". However it is a good example of early excitement about a predictive tool (in this case the characteristic earthquake model) which has been less successful than expected. John Taber _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Yahoo.com new quake variety of subjects Date: Tue, 17 Mar 1998 21:59:40 -0700 Hi all, http://www.yahoo.com has a new section on earthquake related items, and sites of interest. It seems to be extensive for a major search engine such as itself. Finding sites on there, I've never seen before, including the subject of earthquake prediction sites. PSN references and specific major USA quakes of interest. Good and bad...according to individual viewer I suppose. Go to SCIENCE click, then click EARTH SCIENCES, then click GEOLOGY & GEOPHYSICS, then click EARTHQUAKES. Other interesting earth subjects seem to be all over the site. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Ancient Trees Felled During Quake! Date: Tue, 17 Mar 1998 23:06:06 -0800 (PST) Hello All: I just had to post this news item that I came across today: Neskowin, Oregon (US) - People have been making almost a religious pilgrimage to the rugged coastline to see more than 200 tree stumps poking up from the beach. The stumps, thought to be some 2000-years old, are being uncovered by powerful El Nino-spawned waves. Scientists believe these now-dead trees were killed during an earthquake-related event along the Oregon coast. The prevailing theory is that a powerful offshore quake 2,000 years ago dropped the coastline by as much as 7 feet and submerged the sitka, spruce & cedar trees. Major quakes are believed to occur off Oregon every 350 to 500 years. The last one, in 1700, swamped coastal forests and sent tsunami waves across the Pacific so powerful that they destroyed Japanese fishing villages. The recent storms have scoured about 10 feet of sand from the beach, but ocean currents are expected to rebury the stumps by summer. According to one geologist, however, even the sea can't bury what the stumps foretell - another major earthquake. I was wondering if it could have possibly been caused by a volcanic explosion... So, what can others add about the mystery of the tree stumps? Frank Condon mailto:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "John Krempasky" Subject: Re: Ancient Trees Felled During Quake! Date: Wed, 18 Mar 1998 02:57:05 -0500 -----Original Message----- From: Frank Condon To: psn-l@............. Date: Wednesday, March 18, 1998 2:12 AM Subject: Ancient Trees Felled During Quake! > >I was wondering if it could have possibly been caused by a volcanic explosion... >So, what can others add about the mystery of the tree stumps? > No, a volcanic eruption wouldn't cause the ground surface to subside like that over such a WIDE area. This actually isn't very new...such areas like that that on the Oregon/Washington coast that were apparently suddenly submerged have been studied for several years. From this has emerged a picture of these enormous earthquakes occuring over periods of hundreds of years. What causes this are enormous subduction-zone earthquakes of Mag 9 or greater, occuring over hundreds of miles of the fault plane of the Cascadia subduction zone sliding under the North American Plate. Quakes like the magnitude-record-holder off Chile, or the Great Alaska Earthquake (but far worse). Unfortunately, it's been long enough since the last one (1700 seems now to be a fairly certain date) that another is a real possibility in our lifetimes. There isn't an EXACT cycle of 300 years or anything to the cycle - it could happen tomorrow, or 100 years from now. But the danger has been recognized, studied, and looked at by disaster planners; but it probably hasn't totally filtered down to the general public in the Pacific Northwest. This sounds callous, but it would be fortunate in the long term if a 6.2-6.6 occured sort-of-near Portland or Seattle within the next few years , do enough telegenic damage to get huge media coverage, but not cause massive destruction, just to wake people up. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Ancient Trees Felled During Quake! Date: Wed, 18 Mar 1998 07:18:52 -0700 John Krempasky wrote: > > -----Original Message----- > From: Frank Condon > > > >I was wondering if it could have possibly been caused by a volcanic explosion. > >So, what can others add about the mystery of the tree stumps? > > I was under the impression that the Oregon coast was emerging not subsiding. Must be a local thing, eh? > This sounds callous, but it would be fortunate in the long term > if a 6.2-6.6 occured sort-of-near Portland or Seattle within the next few > years , do enough telegenic damage to get huge media coverage, but not cause > massive destruction, just to wake people up. > We call these "Designer Quakes" (originally from Ian Madin, Oregon State Geologic Survey following the Sedro Wolly earthquake). -- ---/---- Charles P. Watson Seismo-Watch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Seismic Prediction Group Date: Wed, 18 Mar 1998 07:38:59 -0700 There was so much promise for the Parkfield experiment. One of the best accomplishments from the project has been an earthquake alert for foreshocks. But with no activity to support the system, emergency managers have begun to question the system. *sigh* -- ---/---- Charles P. Watson Seismo-Watch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Calif EQ Insurance Date: Wed, 18 Mar 1998 08:15:15 -0700 Those interested in earthquake insurance may want to look at this report by the Contra Costa Times: http://www.hotcoco.com/news/business/businessstories/chr45710.htm -- ---/---- Charles P. Watson Seismo-Watch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "John Krempasky" Subject: Cascadia Subduction Zone Date: Wed, 18 Mar 1998 16:49:43 -0500 >I was under the impression that the Oregon coast was emerging not subsiding. Must >be a local thing, eh? > > Here's a few websites.... http://www.eurekalert.org/releases/tsunami-tree.html http://www.geophys.washington.edu/SEIS/PNSN/INFO_GENERAL/SLIDES/atwater/BRAN T/ http://www.netbridge.net/~rogerhart/dogami.html Doesn't seem very local...subsidence from Southern British Columbia to Northern California? I guess it could be a question of scale. The Oregon coast, over the long term (millions of years) could be emerging, but periodically it could suddenly subside, causing parts of it to be suddenly submerged...but the overall trend could be for emergence, I don't know. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: A Remodeled Crawlspace Seismometer Vault Date: Wed, 18 Mar 1998 15:38:36 -0700 I recently finished my new remodeled crawlspace vault. Only as a subject of perhaps minor interest do I present some of the features. Most of the items herein are really a result of the earlier PSN e-mail inquirys on the vault subject and the response of many generous souls. This is not a role model, but perhaps a debatable subject...(feel free to criticize, recomment, or suggest; I'am open to thought). The seismos I have are coil & magnet commercial Sprengnethers, (circa 1960's), but I hope to convert these into very broadband seismometers and a hopefully passive temperature environment seems to be a necessity. I expect alot of tilt and noise in the city of Denver, and subsequent frequent adjustments. The vault is located under the bedroom area of the house, and on a hardpan clay. Due to tilt factors, the area is vaguely less responsive to activity above, although, unfortunately, the bedroom is closest to the street noise. A crude compromise of locations. The vault size was made to be larger than the area needed for the seismos; just for access room, but it is still cramped for headroom. The ceiling height is about 2 & 1/2 foot. Inside the area covers roughly 5' by 10 & 1/2 foot. I hope that the low height may reduce the air current circulation temperature extremes. (It doesn't help for neck cranks-ha.) I used somewhat standard wall materials in the building, a cinder block "foundation", 2 X 6"ers on top, and on up to the floor joists. Common wall insulation is in between the plywood wall sheeting. All efforts was made to seal all cracks, at all stages. The door is really a wall section type construction, with sheet metal reinforcement on the inside of the vault surface. It took along time to make the entrance in comparison to the normal walls. For more vertical space (for the seismos heights consideration), I then dug out about 5-6 inches of clay, where the seismos were to go. Surrounding this "pit", is a 2 X 6" lumber of the pressure treated preservation variety, as a slump "wall". The lumber tops served as a rough leveling guide for a layer of mixed, but dry concrete dumped on and spread to fill in depressions over the bottom area of the box. The dry concrete layer was gently moisturized. When dry it lacks the strength of regular concrete...more like a fracturable sandstone. Next a 6mm thick plastic covering tarp was applied over the ground contours and it is attached to the walls of the vault, a waterproof covering that is. Silicon caulking the edges, makes a waterproof "boat, or "bubble"....whichever. The three piers were built atop this plastic covering. Wet concrete, stepping stne layer, mortar, stepping stone layer, mortar and finally a tile layer, yielded a 5 & 1/2" height by 32" square piers. After drying, the sides of the pier were painted with a tough latex-acrylic paint made by Congo-Pro, as the stepping stones themselves are capable of absorbing moisture. Regular concrete pouring was out of the question due to the distance from the crawlspace entrance and the physical nature involved of crawling, hauling by bucket etc. The top of the piers are not absolutely level as were expected. Eight inch tile squares were used (16 per pier). Eight 16" X 16" X 2" thick stepping stones were used per pier; four to each layer. Some patching of the plastic covering was necessary, and I used silicon caulking for this. Actually, I used alot of silicon caulking and sealing strips, to shut out air cracks on the walls and ceiling....hence the "bubble" wording. The walls and ceiling insulation was partly composed of regular house insulation between the walls and joists. On the 2 outside walls, and inside walls & ceiling I used commercial Reflextex layers to make the total rough R factor of about 40 everywhere, except of course for the floor. Even the cinder blocks of the "foundation" were covered. There is no regular venting of this vault. I feel that the air change sets up too rapid temperature problems which I am trying to avoid. The only air vent is by way of the door cracks at the entrance. A hinged drop down shield in front of the laterally opening door, may eventually be made. I expect some water condensation inside over time, when the door is shut in regular operation. A desiccant is anticipated. Four PVC plastic 3/4" I.D. pipes were run through a wall for any signal or power cables use. Any can be capped inside and outside, if not used. A foam filling product will likely be used for plugging used pipes. The crawlspace by itself, for here, has an older furnace and due to lack of duct insulation, the temperature usually gets no lower in temperature than about 40 degrees even in freezing weather. This was a nice factor in the building aspect especially in the Janruary thru March temperature variations for Colorado weather. The furnace is about ten foot away, but hasn't seemed to affect the previous seismo installation very much. The worst offender is our clothes washer, and I've occasionally had to shut it off during noticed incoming events. Overall the insulation factor is the most important aspect, both for temperature variations and water resistance. With the crawl- space itself, serving as one "box", with some resistance to both upper & lower temperature variations, and the vault as the second "box", and some insulation around the seismos them- selves (the third "box"); the rapid temperature variations should be attenuated alot. The two outer piers will serve for the horizontals, with the center (and roomiest) for the vertical seismo and its more extensive problems. There is limited room for a fourth seismo at the end of the "crawlway", next to a wall. Overhead light fixtures were also installed. The old flashlight routine is out the door. The potential for using the lights as a temperature means is a possibility down the road, but hopefully not necessary. Overall...this was not a cheap project. Nor was it easy to to do. Kneepads were a necessity, as were gloves. I'am not looking forward to this kind of project again...but I hope it overall works much better than before. Time and temperature will tell. I anticipate about a month now of piers stablization adjustments. It seems funny crawling into a clean vault...like an alien environment...that doesn't seem natural. Any day now, I'll drag the seismos in and onto the piers, and begin insulation of them....the third "box". It seems to take forever....... Being a occasional rockhound: there were weathered white quartz and crystalline feldspar pieces. Pegmatite float indication stuff from miles away. Occasionally jagged schist pieces from nearby upslope would show up. I even came across one small piece of petrified wood. I would prefer crystals...the flowers of the mineral kingdom...ha. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Philip J. Del Vecchio,Sr" <75713.3271@..............> (by way of Larry Cochrane Subject: ailer: QUALCOMM Windows Eudora Pro Version 3.0.3 (32) Date: Wed, 18 Mar 1998 16:55:32 -0800 Larry: Quite a discussion going on about forecasting quakes. In 1920. when I was 16, I had subscribed to the Rev. Irl R. Hicks Almanac. I loved everything about science, including a story on four eathquakes which had occured in Los Angeles the previous year. I wrote the editor a letter in which I told the editor that was "some forecast." The forecast was based on observations of a planet they called "Vulcan," which rotated between the orbit of Venus and the Sun. The day after I received the magazine I went to an electrical store where I had been buying the parts for a "crystal" radio receiver, strung wires atop the house roof and listened for anything unusual which might be happened. I listened for days and days until our landlord saw the wires and pulled them all down The nexct years' issue of the magazine carried my letter congratulating them on their marvelous forecast. I still have a copy of that issue of the magazine. If you would like to share this "amazing" story with the group - go ahead, Best regards. Excuse the typing errors - Phil. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Cascadia Subduction Zone Date: Wed, 18 Mar 1998 21:31:14 -0700 John Krempasky wrote: > > >I was under the impression that the Oregon coast was emerging not > subsiding. Must > >be a local thing, eh? > > > > > > Here's a few websites.... > http://www.eurekalert.org/releases/tsunami-tree.html > http://www.geophys.washington.edu/SEIS/PNSN/INFO_GENERAL/SLIDES/atwater/BRANT/ > http://www.netbridge.net/~rogerhart/dogami.html > > Doesn't seem very local...subsidence from Southern British Columbia to > Northern California? > > I guess it could be a question of scale. The Oregon coast, over the long > term (millions of years) could be emerging, but periodically it could > suddenly subside, causing parts of it to be suddenly submerged...but the > overall trend could be for emergence, I don't know. Excellent work. There are many remnant terraces throughout the Pacific Northwest that demonstrate the emergent coast line. In turn, there are also local subsidence basins (usually at the mouths of prominent rivers, have preserved several important geologic deposits. Behind the Coast Range is the back arc basin which is also subsiding. This north-south megadepression includes the Puget Sound and the Willamette Basins. Although it appears on a whole the Coast Range are rising, some earthquakes have caused subsidence within the coastal basinal sediments, one of which was the Great Jan. 27, 1700, Cascadia earthquake. Although I no longer publish the EQNews magazine, I used the Great Jan. 27, 1700, Cascadia earthquake as the cover story for the January 1997 issue. Unfornunately, EQNews got bogged down with declining financial matters and this issue never made it to press. Here is the web site which I created to kick off the issue and the cover story: http://www.seismo-watch.com/EQSERVICES/Newsletter/EQNEWS9701.html -- ---/---- Charles P. Watson Seismo-Watch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Al Allworth" Subject: Re: A Remodeled Crawlspace Seismometer Vault Date: Wed, 18 Mar 1998 23:36:21 -0800 -----Original Message----- From: meredith lamb To: psn-l mailing list Date: Wednesday, March 18, 1998 3:01 PM Subject: A Remodeled Crawlspace Seismometer Vault >I recently finished my new remodeled crawlspace vault. Only as Do you anticipate any problems with the vault structure attached to the floor joists of the house? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: blewis@........ Subject: Date: Thu, 19 Mar 98 08:55:35 PST I'm still here in Silicon Valley...and I have a catalog here that lists zero-length spring stock! It is available in widths from .25 inches to 1.00 inches, thicknesses from .004 to .014 inches, and lengths up to 48 inches. There is a chart that shows that these are true, flat, coiled, strip-type, zero-length springs! The working ID's from .34 inches to 2.63 inches, and loads from .50 to 3.16 pounds. Material is stainless steel. They have a Web site that is not very informative; they tell me that it is "in work". Hope this may help... The company is: Spec Springs Associated Spring-Raymond 800-872-7732 (Gets you the name of the nearest distributor; there are about 8 across the country. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: blewis@........ Subject: Re: Date: Thu, 19 Mar 98 10:16:05 PST A slight correction...the load range for the springs is from .50 pounds to 7.00 pounds; I was looking at the wrong column. The catalog shows also how to "parallel" them for higher loads. They come coiled up, with inner diameters from .40 to 3.50 inches, with an end sticking out where the load would be applied, as needed in the STM-8. This "extension" can be from .61 inches to over 30 inches. ______________________________ Reply Separator _________________________________ Subject: Author: blewis@........ at INTERNET_ROUTER Date: 03/19/1998 8:55 AM -------------------------------------------------------------------------- Your following message has been delivered to the 267 members of the list psn-l@............. at 08:59:36 on 19 Mar 1998. -------------------------------------------------------------------------- I'm still here in Silicon Valley...and I have a catalog here that lists zero-length spring stock! It is available in widths from .25 inches to 1.00 inches, thicknesses from .004 to .014 inches, and lengths up to 48 inches. There is a chart that shows that these are true, flat, coiled, strip-type, zero-length springs! The working ID's from .34 inches to 2.63 inches, and loads from .50 to 3.16 pounds. Material is stainless steel. They have a Web site that is not very informative; they tell me that it is "in work". Hope this may help... The company is: Spec Springs Associated Spring-Raymond 800-872-7732 (Gets you the name of the nearest distributor; there are about 8 across the country. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Re: A Remodeled Crawlspace Seismometer Vault Date: Thu, 19 Mar 1998 12:00:17 -0700 >Al Allworth wrote: Do you anticipate any problems with the >vault structure attached to the floor joists of the house? Al, I suppose with hindsight.... I would have located the vault more toward the center of the crawlspace to begin with (which is where the furnace is), or at least away from the foundation, and not have made any attachment to the house what-so-ever. There is a transfer of tilt influence from the house to the vault frame & seismo. A free standing vault probably would see somewhat less response to house tilt noises transfer. My basic vault frame alone, was built roughly 3-4 years ago, right at a corner of the house foundation. There is some water condensation effects close to the joists where both structures meet. In January, before more extensive insulation began, I could feel the water condensation in 2 specific spots, by inserting my hand into the batt insulation all along the 2 walls where it meets the house foundation. Down the road of time, there will likely be a water damage effect on the vault frame. I figure I could live with the problem, more than a desire to redo or relocate dictate. Luckily, I have not seen any cracks or stress indications....yet. Frankly Al, I think that the whole vault scheme was over done on my part. I think there is a much simpler method. Sometimes I think that by pre-configuring the dimensions of a insulation product/s, versus it fitting over a concrete pad, with observance of seismo height, one could arrive at a suitable housing much sooner, and cheaper. I would also make room for a second inside seismo insulation enclosure. The pictures of the pier & seismo on the Sean-Thomas web site come to mind; as an illustration....seriously. Of course one could engineer anything to death-ha. I'd still use tarp underneath the concrete pad and out aways. Probably support frame 2 X 4's, alot of some kind of glue, silicon, etc. Finally...., if you think its thick enough...slap on Reflextex or something similar. Of course, don't forget the kneepads. Keeping the dimensions straight and level would likely have to be observed absolutely, otherwise the layers of the foam (?), may pop or crack. I'd probably spend more time on the "blueprint", than the actual construction. I suppose the only real personal plus on my vault, is that I can go inside the 2nd "box" (vault), whereas the above approach likely won't have room. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Re: Zero-Length per Spec Springs Date: Thu, 19 Mar 1998 13:37:54 -0700 B. Lewis, Curiosity prevails: Does the catalog show any prices of these zero length springs? Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "John Krempasky" Subject: Oregon Earthquake Disaster Planning Date: Thu, 19 Mar 1998 17:17:24 -0500 I swear I'm not making this up; http://www.cnn.com/US/9803/19/fringe/earthquake.gambling.ap/index.html "State hopes to restore gambling within hours of big quake" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Walt Williams" Subject: Quake-Deficit Article Date: Thu, 19 Mar 1998 19:17:13 +0000 Hello All, FYI. Yesterday, 98.03.18, in the 'Daily News' a San Fernando Valley newspaper local to Canoga Park / Northridge, California, USA area posted: ======================================================== "Seismologists find fault with quake-deficit theory" By Jane E. Allen (AP) Scientists who warned three years ago that Southern California was having too few earthquakes for all the stress on its faults --- and that one good magnitude-8 quake or many more Northridge-size shakers could fill the gap --- now say they were wrong and there's no quake deficit. What's changed their thinking? Researchers went back to the historical record of quakes since 1850. It was used for the 1995 study from the Working Group on California Earthquake Probabilities, produced from models that suggested there should be nearly twice as many moderate to large quakes as have been recorded. This time, the researchers analyzed only those quakes observed since 1903. They assumed records likely would be more complete after the turn of the century because Southern California had relatively few inhabitants before then. With the smaller, more focused study, they calculated that the rate of quakes larger than magnitude-6 was much closer to what the models predicted, Thomas C. Hanks, a geophysicist with the U.S. Geological Survey in Menlo Park, said in an interview Tuesday. (See QUAKE / Page 10) Continued "Southland not short on quakes" (QUAKE / From Page 1) Hanks was scheduled to present the findings today to the Seismological Society of America annual meeting in Boulder, Colo. The paper has been accepted for publication in the summer issue of the Bulletin of the Seismological Society of America. Ross Stein, a USGS geophysicist and study co-author, said the new findings, which pinpoint flaws in a document used for state earthquake policy, hold important implications for earthquake insurance. "If you change that, it's likely you'll change the estimate of earthquake hazard and earthquake loss," Stein said in a telephone interview Tuesday. He said the revised quake catalog compiled by Hanks should be on the Internet within days for others to view. Hanks and Stein also found that the amount of strain released since 1850 by quakes larger than magnitude-7 is "exactly the same" as what has been accumulated by tectonic plates grinding past each other. "They are in balance," Hanks said in a telephone interview. "There is no reason to think there is some deficit out there we need to make up for with a huge earthquake." Nor would there be a need for 11 to 15 more Northridge-size quakes of about magnitude-6.7. In addition, without an earthquake deficit, "there's no reason to expect the number of earthquakes to start dramatically increasing," he said. "Who knows what the future would bring, but there's no reason to think the next 100 years will be a lot different from the last 100 years," Hanks said. At the same time, if a major quake struck sometime soon on a San Andreas segment that hasn't shaken for several hundred years "no one would be surprised." Edward Field of the University of Southern California and David Jackson of the University of California, Los angeles --- a principal author of the 1995 report --- were scheduled today to present a new mathematical model that also finds no quake deficit. However, because the work has been submitted for publication in the journal Nature, Field and Jackson said journal rules prohibited them from discussing details with reporters from other publications. Hanks believes the old model predicted too many quakes in the magnitude-6 to 7 range, because it predicted too few large quakes of magnitudes 7.8 to 7.9. "They only predict two to three per thousand years for all of Southern California. The geologic data would suggest that there's maybe five or six or seven per thousand years," Hanks. ====================================================== Walt Williams, 98.03.19 dfheli@.............. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Canie Subject: Montserrat TV show; Montserrat WWW site Date: Thu, 19 Mar 1998 19:47:33 -0800 >X-From_: owner-volcano@.................. Thu Mar 19 15:49:41 1998 >Date: Thu, 19 Mar 1998 16:06:46 -0700 (MST) >From: Jlschiliro >Subject: Montserrat TV show; Montserrat WWW site >Sender: VOLCANO >To: VOLCANO@.................. >Reply-to: VOLCANO >X-Mailer: AOL 3.0 for Windows 95 sub 18 >Resent-Subject: Montserrat TV show; Montserrat WWW site >Approved-By: Jon Fink > >Just wanted to let you know National Geographic Television is airing a one- >hour film on the Montserrat volcano this Sunday, March 22, at 7:00 p.m. >(Eastern Standard Time) on the TBS Superstation. It will air on a show called >National Geographic EXPLORER. > >It would be great if you could post this information on your list server and >share the news with your colleagues. > >Many thanks and I hope you enjoy the show. >Jody Schiliro >Associate Producer >National Geographic Televison > >============================================================================ > >Date: Thu, 19 Mar 1998 11:33:00 -0400 >From: Robert Fournier >Reply-To: k16305@.......... >Organization: Robert Fournier: Photographer >To: volcano@.................. >Subject: Montserrat > >For those of you who would like to have a live view of Montserrat's >volcano try this url > >http://www.discovery.com/exp/montserrat/cam.html > >Yours, > > Robert Fournier > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Al Allworth" Subject: Re: A Remodeled Crawlspace Seismometer Vault Date: Thu, 19 Mar 1998 22:43:39 -0800 -----Original Message----- From: meredith lamb To: psn-l mailing list Date: Thursday, March 19, 1998 11:29 AM Subject: Re: A Remodeled Crawlspace Seismometer Vault I read with interest what others are doing, because I will soon be building a permanent home for my seismometers. In California I had one bolted to the concrete floor under my workbench. and another ons stuck to the floor near it with dougle sided adhesive foam tape. Both picked up lots of people type of noise, walking 30 feet away, neighbor digging post holes, another neighbor knocking down a concrete block wall. (about 500 feet away), and unusable when I tested my 5KW gas generator. I have a concrete foundation about 5 feet square that was used by someone in the past for the base of a tower. I am planning to use it. It has a conduit running from it to my machine shop building. The only problem - - - It's right next to a walkway, and only about 50 feet from the street with lots of vehicles, school busses, gravel trucks and all else. I wish you luck with yours and will be watching for your reports. al _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: the Mw6.7 quake comments Date: Sat, 21 Mar 1998 13:48:13 +1200 ok gang the 70 minute file was huge ~420 kb for those of u who were patient enuf to download it u would have been greeted with the largest surface wave recording i have so far done. note:... that is at 50sps which accounts partly for its size. it was ~3/4 of an hr after the commencement of the event b4 sdr LP channel stopped signal stopped saturating and there was another half an hr of signal after that b4 it was lost in the standard background noise. this event was very shallow placed at 10 km and that accounts for the rich surface wave activity. cheers Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: FISHING LINE FOR LEHMAN SEISMOGRAPH Date: Sun, 22 Mar 1998 00:45:52 EST I understand that there is a special stainless steel fishing line or leader (which dosen't stretch) that some have used for lehman seismographs. Could someone advise me of the name of this product. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: Precession magnetometer Date: Sun, 22 Mar 1998 11:52:35 +0000 Hi, Have just found interesting web site with good links to some more info on mags....A Potassium mag is described in the link to 'Geophysicist'. Other link is to 'Novice'.....(that's me ) NO constructional details tho'. : ( http://www.ultramag.com Regards Albert Noble (England) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: STM design spring Date: Sun, 22 Mar 1998 21:17:40 -0600 (CST) Re. the consideration of the need for a zero-length spring for the STM vertical seismometer: some clarifications are in order: 1: The spring used is NOT a zero-length spring. I have been careful to always say that it "exhibits zero-length behavior" when it is bent in an arc with about a 5.5" opening. Having zero-length behavior allows for relatively long periods; and this spring will allow infinite periods: aka instability, when bent in certain geometries. This is not desirable, since it allows the thermal problems, etc, to get out of hand. For the VBB transfer function, a mechanical period between 2 and 10 seconds is sufficient. 2: Note that the mechanical period is the ONLY function of the spring that shows up in the transfer function that determines the instrument response. It is important that this period is relatively stable over time, since it directly impacts the damping of the VBB response. 3: The most important consideration here is that we are trying to keep this seismometer design as simple as possible, while still achieving a low noise VBB response that maintains a stable calibration over time. THE major noise of vertical sensors is usually due to ringing of the suspension spring. THis is why single leaf springs are greatly preferred over coil springs. The most serious resonance of a bent leaf spring is the vibration of the center of mass (the outward portion of the bend), which is about 50 hz in the current STM design. (This vibration is damped by rare-earth magnets inducing eddy currents in a copper bar.) In the STM design, lateral and torsional vibrations are forced to be at rather high frequencies by the full width mounting bar across both ends of the spring. 4: In the STM design, the suspension spring is used in compression, pushing up on the underside of the boom via flexures that allow the whole leaf spring to bend in an unrestrained curve, so that none of the mechanical rigidities of the spring itself get involved. Even if one wanted to use a coiled zero-length spring, they cannot be made in a compression configuration, since the zero-length behavior is achieved by twisting the spring material as it is coiled, so the spring requires an initial force just to open the coils. So in classical vertical seismometers, the spring is above the boom, working in tension, and suspended in a fashion that provides very little control of spurious oscillations and resonances. These seismometers were designed for a very narrow band response, where the data passband was well away from the spring noises. Even the famous 1-hz L4-C has nasty resonances from its' circular diaphram springs that start at 16hz. 5: So the bottom line here is to keep things as simple as possible, concurrently with being low cost. If one really wants a deal on the 0.018" spring material, it is available in 26 foot rolls for something like $75 from McMaster supply. (About $3 per spring). For a single seismometer, the hardware store is a better deal. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: info for today's NZ quake Date: Mon, 23 Mar 1998 16:24:24 +1200 for those who want to add it to my winquake files i posted earlier U.T.: 1998 March 22 1317 NZST: 1998 March 23 1.17 a.m. Lat, Long: 45.08S 166.86E Location: 76 km west-north-west of Te Anau Focal depth: 12 km Magnitude: 4.8 Felt at Manapouri, Te Anau area 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: meredith lamb Subject: STM-8 design question Date: Sun, 22 Mar 1998 21:57:49 -0700 Hi Sean-Thomas, Was wondering about a re-arrangement feasibility of the speaker magnet and the vrdt. If boom extensions were made that moved the speaker coil down; with the speaker magnet resting on the base plate...and the vrdt sensor was raised much closer to the boom, would there be any benefit? Perhaps the extension could be a aluminum spacer/tube attached at one end to the boom, and the other end holding the coil by various means. Or would the problems involved create more effort and possible mechanical noise than desired? Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: PSN dinner at John & Jan Lahr's Date: Mon, 23 Mar 1998 09:30:13 -0700 PSN- Last Thursday night, 19 Feb, Jan & John Lahr hosted a very pleasant dinner for Sean-Thomas Morrisey and some other PSN members, Meredith & Lee Ann Lamb, Benjamin & Sandy Gardner, and myself. Sean-Thomas was in town to attend the annual Seismological Sociey of America Meeting held in Boulder this year at which he presented a poster, "Response, Calibration, and Noise of the Homemade Hardware Store Broadband Leaf-Spring Vertical Seismometer". Jan prepared an excellent meal, John made some interesting demonstrations with magnets, the cats performed (Sulcha, in particular), and S-T elucidated some of the theory of operation of his seismometer. -Edward -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Karl Cunningham Subject: Re: STM design spring Date: Mon, 23 Mar 1998 08:30:50 -0800 Hello Sean-Thomas -- Thanks for the words on spring design. Question: I notice in your diagram on the STM-8 the bottom anchor of the leaf spring is not directly under the top end. Is this done to achieve a desired transfer function of the spring? For some other reason? Thanks for your help. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: STM design spring Date: Mon, 23 Mar 1998 14:47:09 -0600 (CST) Karl, The change in the spring geometry was a result of moving the center of mass of the boom to be 1 inch above the center of rotation of the hinges. This was done so that a fully flexured attachment of the upper end of the spring could be used, while maintaining the location of the lifting force (applied by the round fixed rod attached to the spring via the flexures) in line with the center of the hinges. Because of the spring end flexure, the floating clamp bar on the end of the spring will move along the axis of the boom as the boom moves vertically, causing instability. This was not the case on the prototype; the upper end of the spring was not flexured, but simply clamped to a round bar that rested in a broad semi- circular groove under the boom. In experimenting with the tradeoffs between period ( trying for 4 to 6 seconds) and stability, while keeping the other mechanical constants the same (mass = 0.5kg), this configuration seemed the most desirable. Beyond this, there is nothing critical about it. My experimenting was limitated by the arbitrary spacing of 1 inch between the holes in the base and the boom. Intuitively it makes sense to me to have the spring force applied at a small reverse angle when the CM of the boom is above the CL of the hinges, but I haven't actually modeled it. But as far as the transfer function is concerned, the only parameter that the spring and spring geometry affects is the mechanical period. We really need to know absolutely nothing about the spring itself. This is one of the great advantages of the triple feedback VBB system. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: STM-8 design question Date: Mon, 23 Mar 1998 20:41:47 -0600 (CST) Meredith, First I want to thank you for being at J. Lahar's for dinner last thursday and bringing your interesting hardware. I regret that I forgot to bring an assembled VRDT to demonstrate. Regarding your question about lowering the speaker (feedback) coil and magnet to the seis baseplate and mounting the VRDT up near the boom (to keep it away from the main magnet): it is certainly possible. The only concern I would have is that the lightweight boom is not very rigid and can twist, and an extension down to a lowered magnet would exaggerate the rotation and might cause alignment problems of the coil. Spurious oscillations about the axis of the boom would be of significantly lower frequency, possibly in the passband of the VBB output. A more rigid boom would address these problems, if it can be kept lightweight. I sort of like the outdoor electrical boxes that support the magnet; they are screwed together internally, and a length of 3/16" stainless steel or brass threaded rod goes through the hole in the center of the magnet, with nuts both above and below the magnet core (to fasten it to the upper box), through the boxes, and through a large clearance hole for adjustment (with stainless washers) in the baseplate and is fastened with a wingnut when the magnet-coil alignment is correct. I remove the magnet assembly before moving the sensor. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Barometric Pressure Change Sealed Seismo Container Date: Mon, 23 Mar 1998 20:01:09 -0700 The STM-8 seismo looks like a good candidate for an air sealed container of some sort. The idea is too just seal it, and not to vacuum the air out, to alleviate barometric pressure changes. Does anybody have any ideas, outside of fish tank glass units; of something that would do the job, thats commercially available and adaptable that doesn't cost a mint? I've speculated on a giant cooler, but I doubt its ability to seal, and it would probably flex too much and the linear lip would not likely be linear to the lid alignment. A plexiglass container with rubber gaskets might work with alot of effort, and cost? Metal containers don't seem to be around. Perhaps a welded large metal tube may work, but again with a possible much higher cost, than even plexiglass. Kind of stumped for a container. Any ideas out there, or experience of this sort? Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: STM design spring Date: Mon, 23 Mar 1998 19:28:37 -0800 Hi All Sorry for the lack of understanding but I am confused about the concept of a zero length spring. I saw the graph with the load vs length projected back to zero. I thought what would give large periods would be springs with zero or very low stiffness. The larger the spring stiffness the higher the oscillation frequency.Could someone shed some light on this. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Warner Lindholm Subject: Re: STM design spring Date: Mon, 23 Mar 1998 20:04:47 -0800 (PST) With the spring and flexure configuration that Sean's STM-8 has, there can be two boom positions where the torque around the boom hinge is zero. One position is stable, the other is not. Or so my Matlab model tells me. The key to the nearly zero-length behavior are the spring flexures. These cause the spring restoring force vector to move in such a way that the torque due to the spring has an almost parabolic shape. Where the torque maximum occurs with respect to boom angle depends on the relative position of the spring flexures. The boom mass creates an opposite torque which is also parabolic but in the opposite sense. This torque is maximum when the boom is horizontal but decreases for angles greater or less than zero. As the upper flexure is moved outboard, spring torque increases even beyond the point where upper and lower flexure are inline and perpendicular to the boom because the lever arm is lengthening. So by playing with the mass and with the upper flexure position one can control where these two curves intersect. If the curves just barely intersect the effective spring constant is small and changes little for boom angles near zero because the operation is near the extremes of both curves. In practice I've found it pretty easy to get a period of 4.5 seconds but much beyond that is tricky because boom excursions caused by temperature effects can drive the system into unstability. I think it's a pretty nifty scheme. Sean-Thomas, my hat's off to you. BTW, for the rig I constructed to experiment with, (it's not a seismometer yet) I used epoxied-on 90 mesh screen-printing polyester fabric for the flexures. So far no problems with it. -Warner _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Al Allworth" Subject: Re: Barometric Pressure Change Sealed Seismo Container Date: Mon, 23 Mar 1998 22:00:58 -0800 -----Original Message----- From: meredith lamb To: psn-l mailing list Date: Monday, March 23, 1998 7:04 PM Subject: Barometric Pressure Change Sealed Seismo Container >The STM-8 seismo looks like a good candidate for an air >sealed container of some sort. The idea is too just seal it, >and not to vacuum the air out, to alleviate barometric >pressure changes. Millitary equipment cases are available at some surplus outlets. Some of them are ait tight and have a valve to equalize internal pressure. The only place I am familiar with is C & H Sales in Pasadena. They have a catalog but don't put the cases in it because there aren't enough of the same size to make it worthwhile. There must be others that sell them. They aren't the sort of thing that would be worth shipping around the country. Much of the surplus equipment is sold without field cases. Where do the cases go? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Bob Thomasson <102073.3346@..............> Subject: Barometric Pressure Change Sealed Seismo Container Date: Tue, 24 Mar 1998 06:12:05 -0500 <> Meredith, Maybe I'm missing some information here, but a sealed container would hav= e to have an absolutely stable temperature, as even a slight change in temperature in a sealed container containing air or any gas will result i= n a relatively drastic pressure change. Regards, = Bob Thomasson _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: STM design spring Date: Tue, 24 Mar 1998 07:34:31 -0600 Hmmm, I have a great huge roll of stainless steel screen-printing fabric. I wonder how that would work for the flextures? >BTW, for the rig I constructed to experiment with, (it's not a seismometer >yet) I used epoxied-on 90 mesh screen-printing polyester fabric for the >flexures. So far no problems with it. >-Warner _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: Barometric Pressure Change Sealed Seismo Container Date: Tue, 24 Mar 1998 09:38:42 -0800 A couple of ideas: Get a 55 gal. drum with the removable lid such as was used sometimes to ship plastic pellets and such. You could put the whole STM-8 inside easily. There was also a miniature version of this about 3 ' high by maybe 14" in diameter. I believe they shipped ammunition in it. Also this size I seem to remember being used to ship bulk pack grease. In larger cities there are dealers for used barrels that you could try. The second way would be to get PVC pipe in a large diameter and get end caps for it. I know the pipe is available in big sizes, I'm just not sure about the end caps. Hang around a large construction site and get a piece of scrap as they install the sewer system. The end caps are not absolutely necessary. I built a vacuum caster by starting with an ammo barrel like above, then used a 1" thick piece of plywood that I epoxy painted (to seal it), together with a sheet of rubber (like tire inner tube thickness) to act as a gasket. This worked great. For seismo use I would probably look at epoxying a sheet of aluminum on the plywood surface in order to make a leak proof surface. And it you don't vacuum any more than is necessary to hold the lid on, the forces should be reasonable and not separate the sheet from the plywood. Charles R. Patton _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: travel-time calculator Date: Tue, 24 Mar 1998 11:49:16 -0700 John- I just ran the travel time calculator for a SPECIFIC event in eastern California, 5.2 98/03/05 21:47:40 36.08N 117.62W 0.7 20 mi SSW of PANAMINT SPRING recorded by Bob Ogburn in Daly City, and I received some really cool and useful travel times. When I ran the version for a RECENT event (specifying N. Californian catalog), I received the following: > Travel Times to Your Seismic Station > Based on the information that you submitted. > Quake parameters are from the command: finger quake@................... > Station Coordinates: 37.6800 -122.470 > Maximum distance of interest (degrees): 20.0000 > Minimum magnitude of interest: 5.00000 > Compute travel times for P, Pdiff, PKP, PKiKP, S, Sdiff, SKS, SKiKS > Use your browser's BACK button to return to the form for customizing your selection of > arrivals. I don't appear to be getting any arrivals. What am I doing wrong in the latter case? Thanks, Edward PS. This is the first time I have used the calculator, and it is very nifty! -- 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: Roger Baker Subject: Re: Barometric Pressure Change Sealed Seismo Container Date: Tue, 24 Mar 1998 13:01:27 -0600 Friends, I like Charles Patton's idea of using a 55 gallon drum on the grounds that it is roomy and easy to get, would help even out temperature changes by quite a bit, and also act as a somewhat effective magnetic shield as a bonus. It would be best to attach a pressure guage, probably, to see that a slight vacuum is being properly maintained. A major problem might be sealing the lid. A method that I use for making hermetic seals of glass to glass is to smear a flat warmed glass surface with a very thin layer of beeswax. A flat rim that is to make hermetic contact is supplied with a continuous bead of silicone rubber and then placed in carefully positioned contact with the waxed glass and allowed to set up for up to a day or so. When the joint is warmed, the pieces will slide apart and you have a permanent rubber bond attached to one of the surfaces, which makes a good gasket under slight vacuum, when the same alignment of contact is maintained. The section being cured cures inward as the acetic acid in the uncured rubber diffuses into the air, so the gasket area should not be made very wide or the interior portions will not have time to set up. This principle could be used in various other cases. Silicone rubber bonds very well to both aluminum and glass, and to some organic paint type coatings, but not very well to most metals if you want a permanent bond. --Yours, Roger _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: Outreach Information, #3 - Resources, etc. Date: Tue, 24 Mar 1998 12:12:51 -0700 Peter- I would like to display our poster, "Public Seismic Network (PSN): a Model for Preparing People to use Real-time Information About Natural Hazards" Edward Cranswick and Benjamin Gardner (U.S. Geological Survey, MS 966, Box 25046, Federal Center, Denver, CO 80225, USA; 303-273-8609; cranswick@......... Public Seismic Network (http://psn.quake.net/, psn-l@.............. that we presented at the American Geophysical Union meeting in Dec 1997 at San Francisco. Attached is a copy of the abstract. Thank you. -Edward > (1) INTERNAL COMMUNICATIONS - USGS 1998 POSTER REVIEW > This 10th almost-annual poster display will take place Thursday, April > 30, in Building 25, Lecture Halls A&B. Our thanks to everyone who has > offered to display posters here, which have been displayed at other > scientific meetings throughout the past year. We now have about 28 > posters promised, and can accommodate up to about 10 more. If you > contacted me about displaying a poster, you'll be receiving another > email from me very shortly, with details about submitting an email or > diskette version of your abstract in a standard format. If you haven't > contacted me yet but are still interested, please send an email. -- 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: Steve Hammond Subject: Re: Outreach Information, #3 - Resources, etc. Date: Tue, 24 Mar 1998 12:51:08 -0800 Hi Ed, I have some recent examples of how PSN members are reaching out into the = community which you may want to mention when convincing folks that this i= s important. Especially if you are going to talk about supporting the com= munity. I'm sure there are more examples and people need to speak up (l= ike Charlie in Tenn.). In conjunction with science awareness, Jan Froom recently spent a few day= s teaching several classes (with 20 or so students in each one... ) at a = Gilroy school about earthquakes and seismology. He also installed a seism= ic station which is now operational and the teachers/kids maintain with J= an's help. Sam Gazdick and I just finished working on-site with curator John Dillion= at the Randall Children's Museum in San Francisco. This work is in conju= nction with a major display on earthquakes that is due to officially open= at the Randahll on April the 18th . (I have taken some digital photos of= the display and can email them to you.) Sam did all the work setting up = a seismograph and thermal chart recorder. The folks at Berkeley are worki= ng on a telemeter link to real-time data to be displayed. There is a touc= h screen system running the museum version of Seismic. The USGS has helpe= d with some hands-on fault line displays. Joe Sena of the USGS originally= started the planning before he retired and moved south. I put together = a donated "Make a quake" display system where kids jump up and down and = see the trace output on a PC screen simulating an earthquake trace. This = was also a combined PSN effort because Dick Chelberg donated the A/D brea= kout box, Jan Froom donated the IBM DACA card, I built the pre-amp and se= tup a PSN donated PC, and Ted Blank reworked EMON so that it would never = save a file. At the heart of the display, is a full-size 1906 earthquake = building. It was donated and built by the San Francisco Carpenters Union.= It follows the original plans used to build thousands of temporary house= s, erected in the city parks following the 1906 earthquake. As a team all= these people worked together with Randall curator John Dillon (and other= s unnamed) to develop a really impressive display that several thousand c= hildren will visit over the next year. Regards, Steve Hammond PSN - San Jose Edward Cranswick wrote: > Peter- > I would like to display our poster, > > "Public Seismic Network (PSN): a Model for Preparing People > to use Real-time Information About Natural Hazards" > > Edward Cranswick and Benjamin Gardner (U.S. Geological Survey, > MS 966, Box 25046, Federal Center, Denver, CO 80225, USA; > 303-273-8609; cranswick@......... > Public Seismic Network (http://psn.quake.net/, psn-l@.............. > > that we presented at the American Geophysical Union meeting in Dec 1997= > at San Francisco. Attached is a copy of the abstract. > Thank you. > -Edward > > > (1) INTERNAL COMMUNICATIONS - USGS 1998 POSTER REVIEW > > This 10th almost-annual poster display will take place Thursday, Apri= l > > 30, in Building 25, Lecture Halls A&B. Our thanks to everyone who ha= s > > offered to display posters here, which have been displayed at other > > scientific meetings throughout the past year. We now have about 28 > > posters promised, and can accommodate up to about 10 more. If you > > contacted me about displaying a poster, you'll be receiving another > > email from me very shortly, with details about submitting an email or= > > diskette version of your abstract in a standard format. If you haven= 't > > contacted me yet but are still interested, please send an email. > > -- > 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 (PSN): a Model for Preparing People > to use Real-time Information About Natural Hazards > > Edward Cranswick and Benjamin Gardner (U.S. Geological Survey, > MS 966, Box 25046, Federal Center, Denver, CO 80225, USA; > 303-273-8609; cranswick@......... > Public Seismic Network (http://psn.quake.net/, psn-l@.............. > > When an earthquake occurs, unlike any other natural hazard, every indiv= idual in the population at risk is aware within seconds that a dangerous = event has happened. Without the aid of any technology, the consciousness= of everyone affected is almost instantaneously focused on the same subje= ct. Instead of soliciting that information, authorities broadcast the re= dundant message that an earthquake has occurred. A program of monitoring= natural hazards for the public requires public participation to effectiv= ely mitigate those hazards. The Public Seismic Network (PSN), rather tha= n relegating them to the role of sitting ducks waiting to be devastated b= y the unexpected, enables people to become aware that earthquakes are par= t of normal, on-going Earth processes. The PSN is a rapidly growing inter= national group of amateur seismologists, concentrated in California, who = record earthquakes with their own digital seismographs and exchange wavef= orm time series and communicate with each other via the Internet. At pre= sent, the PSN consists of about 50 seismograph stations, about 250 subscr= ibers to its email list server, and about 10 websites. In urban areas of= high seismic risk, a grassroots organization like the PSN -- equipped wi= th low-cost, mass-produced, standardized strong-motion seismographs -- co= uld vastly increase the spatial density of sampling ground motions. This= organization would form a constituency of well-informed residents who no= t only know how to respond to catastrophic earthquakes but also support h= azard mitigation programs in the community. Rather than just building fa= ster ambulances to mitigate the impact of heart attacks, it is more effec= tive to modify the public habits of exercise and diet. The PSN is a mode= l for using technology to connect human awareness to, rather than shield = it from, the environment. > > AN: U51A-05 > LO: MC HALL D > HR: 0830h > DA: Friday > TI: Public Seismic Network (PSN): A Model for Preparing People > to Use Real-Time Information About Natural Hazards > AU: *E Cranswick, B Gardner > MN: Fall Meeting 1997 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Re: Barometric Pressure Change Sealed Seismo Container Date: Tue, 24 Mar 1998 17:40:38 -0700 Al Allworth, Thanks for the reference to military equipment cases. I went to a local surplus store and low and behold they did have acouple cases. Both were air tight models and even had a pressure release screw on the front panel. These were French anti-tank missile cases, solid welds of arc and spot weld. The cases luckily for me were 12" X 12" X 25" long, with one end being the lid with 4 pressure latchs. $19.95 each. It was very unusual to find something that would work right off the bat. This I can handle in a crawlspace easily. Thanks Al. Bob Thomasson, You're right... and I think I was doing wishful thinking about a sealed container with any kind of air in it, and ignoring the temperature part. Guess that I'd indeed need a vacuum pump, and a good temperature control environment. Thanks for the correction Bob. Charles Patton, Alot of good ideas for containers and the lids. The round containers would likely need some kind of platform built into them for the seismo base. Perhaps..(?) the barrels or tubes are first sunk into concrete aways, with containment to allow the lid mechanism access. Insulation could then be applied over perhaps the barrel AND concrete base?? Then perhaps a housing if outdoors (low profile). Good stuff Charles! Roger Baker, I think I'll try your beeswax & silicon approach on the containers I obtained. The rubber gaskets were old, cracked, disintegrating. They have a round "tongue" on the lid, and a 3/8" wide "groove" on the container edge contact. The metal is steel, but I can always try the method first and wait and see, and take it out later if it doesn't work, and try something else if I have too. Think I'll put them initially together with less than the full latch range, and when dry, I'll do the full latching. I haven't heard of this method before. Thanks alot Roger. Thanks to you all for the responses, I think all my questions were fully answered and resolved......fast! Have more things to do with the containers first of course, but they sure look much better than I'd hoped for. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: Barometric Pressure Change Sealed Seismo Container Date: Tue, 24 Mar 1998 20:50:24 -0600 (CST) Roger, Meredith, and all, A pressure contaiment for the vertical would reduce the barometric noise by a factor greater than 100. There are several important points that need to be considered: 1: It does not have to be evacuated, just vacuum tight. Most commercial VBB sensors are not evacuated; even the 1965 gravimeter we are operating to record earth tides is simply sealed in a cylinder of 1/2" plexiglass with double active heaters for stability. (and remote control centering, etc.) 2. Evacuating a container has to be done with great care and a certaity that it will not implode: it should probably be designed for such. Atmospheric pressure on the end of a 12" diameter surface is a total force of 1700 pounds. 3: Enclosing the seismometer means that the container has to be rigid enough that it doesn't significantly flex with external pressure changes. To get a feel for the rigidity required, consider a barometric pressure change of 1/2" on the Hg scale of 30" = 1 atmosphere = 15 lbs/square inch. The 1/2" change is about 1/4 lb/sq.in. So if the area is 1 square foot, this is a total change of force of 36 pounds. Suppose (for the discussion), that 1/4 of this is applied just at the center of the side of the box, like putting a gallon jug of water on it. It should not measurably deflect. 4. This is particularly important for the base of the container that supports the instrument and provides the contact between the seismometer and the pier. The major commercial VBB sensors have bases of Stainless steel or aluminum that are 1 to 2 cm thick, and the covers are coupled to the base with O-rings so that flexing of the cover is not transmitted to the base. The major exception is the STS-1, which has a thick Pyrex baseplate that is vacuum-grouted to the pier itself, and a 30cm dia glass bell jar over the sensor for the vacuum. 5. Once you have your seis in a suitable container, you will need some method to remotely center it, like a small toy motor geared down to a fine threaded rod arranged to move a trim mass along the boom. (The motor itself could be designed to be part of the effective mass; power would have to be minimal to be able to be connected through the fine wires across the hinges). If you even partially evacuate a suitable container, the mass will float down, so remote centering would be a must. 6. You will also need to arrange a vacuum tight method of getting the electrical signals through the wall of the container. A good electronics surplus store might help with connectors. I have has some success with sealing flat ribbon cable into a thin slit with silicone sealant. Also, a practical note: I have found that a plexiglass porthole or two to allow lighting and viewing the inside of the container can be quite handy. Especially if your "remote centering" consists of a rod through a tight feedthrough that reaches over the boom and allows manual positioning of the centering trim weights. 7. So what am I considering for the next STM design? I need to make it shorter than 11" to get it to fit into a large pressure canner. The canner is all cast aluminum, seals tight, etc. In the mean time, I'm looking at a 20 gallon aquarium with a 1/2" acrilic cover. At the 20 gallon size, some are available with 3/8" thick glass sides and bottoms for lt. $50. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: MOINSTER QUAKE NOW!!!!!!!!!!!! Date: Wed, 25 Mar 1998 15:25:51 +1200 ALERT!!!!!!!!!!!!!!!!!!!! recording huge S waves 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: Kees Verbeek Subject: Re: MOINSTER QUAKE NOW!!!!!!!!!!!! Date: Wed, 25 Mar 1998 05:17:33 +0100 (CET) At 15:25 25-03-98 +1200, you wrote: >ALERT!!!!!!!!!!!!!!!!!!!! >recording huge S waves > > >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 > > have them also here in holland. greetings Kees Verbeek _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Charlie Plyler Subject: Quake Date: Tue, 24 Mar 1998 23:28:21 -0500 USGS AutoDrm listing 199803250325:25Mar1998 03:12:30.7 63.9S 150.8E 33 MB=7.1 C A BALLENY ISL REGION Kees Verbeek wrote: > > At 15:25 25-03-98 +1200, you wrote: > >ALERT!!!!!!!!!!!!!!!!!!!! > >recording huge S waves Charlie Plyler Elfrad Group 35.728N/80.81W cplyler@............. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Canie Brooks Subject: Re: MOINSTER QUAKE NOW!!!!!!!!!!!! Date: Tue, 24 Mar 1998 20:25:15 -0800 This was on the IDC List... a 1998/03/25 03:13:04.9 65.94S 153.78E 30 mb 6.1 Balleny Islands Region a 1998/03/25 03:12:24.6 62.82S 150.25E 53 mb 5.8 Balleny Islands Region At 03:25 PM 3/25/98 +1200, David A. Nelson wrote: >ALERT!!!!!!!!!!!!!!!!!!!! >recording huge S waves > > >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 > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: MOINSTER QUAKE NOW!!!!!!!!!!!! Date: Wed, 25 Mar 1998 16:33:20 +1200 >> >have them also here in holland. > >greetings Kees Verbeek great one Kees its a biggy somewhere in the pacific its over an hr now sibnce the start of the event and my LP seismom. is still recording huge amplitude surface waves. time of writing this 0430 UTC Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: ACole65464 Subject: Re: MOINSTER QUAKE NOW!!!!!!!!!!!! Date: Tue, 24 Mar 1998 23:35:00 EST Hi PSN, I was giggling wires the moment the P waves arrived and I though I did something wrong. But I just sat back, watching the impressive surface waves that this event is generating. This is a really big event. At the moment it has been going for over an hour and the radio has not said where it is at! I am glad to be at home to watch the pens roll around across the paper. I pray that there is minimal loss of life from this large event! Allan Coleman Edmonds, Washington _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: MOINSTER QUAKE NOW!!!!!!!!!!!! Date: Wed, 25 Mar 1998 16:48:06 +1200 At 08:25 PM 3/24/98 -0800, you wrote: >This was on the IDC List... > >a 1998/03/25 03:13:04.9 65.94S 153.78E 30 mb 6.1 Balleny Islands >Region >a 1998/03/25 03:12:24.6 62.82S 150.25E 53 mb 5.8 Balleny Islands >Region > all toooooooooooooo low :)))) idc is computer generated and is always very low Prelim mag. from the tsunami warning centre is 8.0 this is a HUGE event WEST COAST AND ALASKA TSUNAMI WARNING CENTER/NOAA/NWS ISSUED MAR 25 AT 0426 UTC ...THIS IS A TSUNAMI ADVISORY BULLETIN FOR ALASKA, BRITISH COLUMBIA, WASHINGTON, OREGON, AND CALIFORNIA ONLY... AT THIS TIME NO, REPEAT NO, WATCH OR WARNING IS IN EFFECT FOR ALASKA, BRITISH COLUMBIA, WASHINGTON, OREGON, OR CALIFORNIA AN EARTHQUAKE, PRELIMINARY MAGNITUDE 8.0, OCCURRED AT 1812 AST ON MAR 24, OR 1912 PST ON MAR 24, OR 0312 UTC ON MAR 25. THE EARTHQUAKE WAS LOCATED IN THE GENERAL AREA OF: PACIFIC-ANTARCTIC RIDGE NEAR 63.2S, 150.3E. 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: barry lotz Subject: Re: MOINSTER QUAKE NOW!!!!!!!!!!!! Date: Tue, 24 Mar 1998 20:45:44 -0800 Picking it up here also. Whew! Barry David A. Nelson wrote: > > >> > >have them also here in holland. > > > >greetings Kees Verbeek > > great one Kees its a biggy somewhere in the pacific its over an hr > now sibnce the start of the event and my LP seismom. is still recording > huge amplitude surface waves. time of writing this 0430 UTC > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: ACole65464 Subject: Re: MOINSTER QUAKE NOW!!!!!!!!!!!! Date: Tue, 24 Mar 1998 23:57:57 EST Dave, The Live Internet Seismic Server has all its on-line sites showing one huge mass of lines on their seismograms. This is a BIG event. Allan Coleman Edmonds, Washington _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: A Vacuum tight, but not evacuated container Date: Tue, 24 Mar 1998 22:02:18 -0700 Hi Sean-Thomas, I also wish to say that the dinner, activities, and STM-8 discussion with you and John Lahr & Edward Cranswick and all the ladies was a TOTAL delight. In regards to the vacuum tight, but not evacuated container which you mentioned in your last message; I would think that from that, that my container would work alright...without the vacuum. My question/s is in regard to its time period of barometric fluctuations and any noted results and problems associated with it? I.E., is there alot of mass position drifting during weather fronts, that is above normal from that of a non-shielded seismo/container? Is there alot of noise from the container itself, during these changes? Basically, what would one expect, if they had such a container? Mine is a somewhat rectangular braced but standard gauge steel unit. I can appreciate that a stronger unit or a round one would be better, and the need for lines, viewing ports etc. If my steel unit was encased in concrete, except for the rounded lid, would that re-enforce the unit as a whole, significantly? Could this apply to other types of containers also? Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Liberio Rossi" Subject: Big event Date: Wed, 25 Mar 1998 05:05:44 +0100 Just few minutes ago I recorded the a.m. event. Mine data : Lat.43°54'79 Long 10°31'56 liberio.rossi@........ Liberio Rossi From: "David A. Nelson" Subject: Re: MONSTER QUAKE NOW!!!!!!!!!!!! Date: Wed, 25 Mar 1998 17:13:38 +1200 At 11:57 PM 3/24/98 EST, you wrote: >Dave, > >The Live Internet Seismic Server has all its on-line sites showing one huge >mass of lines on their seismograms. This is a BIG event. > >Allan Coleman >Edmonds, Washington yes been following the aslwww site from the start every site throughout the world is showing huge amplitude its a great site the other other great one is the Berkeley make ur own seismogram site http://quake.geo.berkeley.edu/bdsn/make_seismogram.html ya want to try that one too !! this event is only ~2300km from me ( to the south of me) cheers Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Pinpoint Earthquake News Subject: Re: Big event Date: Tue, 24 Mar 1998 21:27:16 -0800 (PST) Would someone please send me a trace as attachement on this Q tonight for web site...I will wait up til 12 mid Pacific...Would appreciated varied traces... Bob Pinpoint Newsletter _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Arie Verveer Subject: Balleny Island event posting Date: Wed, 25 Mar 1998 20:04:03 +0800 Hi, The earlier posting of the Balleny island event, displays the incorrect magnitude and comment. In my rush to post the event, I used the IDC evaluation. Please change the comment field with the USGS's data. I which to thank Dave Nelson for pointing out the possibility of interruption errors with the Automated IDC computes. If in the future an event occurs and the IDC is the only source, I'll place the words (IDC) in the comment field. This type of thing happens for small regional events. Thanks. Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Seisguy Subject: Fwd: USGS Earthquake report Date: Wed, 25 Mar 1998 09:16:07 EST O.K., looks like we're official at M7.9 Mike O'Bleness Northridge, CA Magnitude 7.9 earthquake near BALLENY ISLANDS REGION 63.55S, 150.58E depth 33.0km Wed Mar 25 03:12:30 1998 GMT An earthquake has occurred. Following is information provided by the National Earthquake Information Service of the USGS. This information is preliminary and subject to correction. Time: GMT Wed Mar 25 03:12:30 1998 (EST Tue Mar 24 22:12:30 1998) (PST Tue Mar 24 19:12:30 1998) Magnitude: 7.9, determined using its surface wave characteristics Epicenter: 63.55S, 150.58E (BALLENY ISLANDS REGION) Precision: B, where A is fine and D is coarse. Depth of focus: 33.0km below sea level at the epicenter. Note that the depth of focus is given as 33.0km, indicating that the depth was known to be shallow but could not be determined precisely. For a map showing this event, please consult the web page Further info can be obtained from the USGS National Earthquake Information Center at or the USGS home page at You will continue to receive messages like this when earthquakes occur that have magnitude 5.0 or more in the continental US, Alaska, and Hawaii, and 6.0 or more anywhere in the world The subscription form for this service is at If you do not wish to receive these messages, please visit that subscription form, enter your email address, and select "unsubscribe". If that does not stop the messages, please send email to info@................ -- U.S. Geological Survey -- Science for a Changing World From: lahr@.................. Subject: Re: Outreach Information, #3 - Resources, etc. Date: Wed, 25 Mar 1998 09:03:34 -0700 (MST) Steve, Thanks for the great summary of PSN activities in the Bay Area. I think it would be a good idea to include this, and other examples of PSN outreach and education efforts, on one of the PSN web sites. Maybe some of it is there already. I'm imagining a page with: Public Seismic Network Reaches Out Around the world, PSN members are involved in many efforts to educate the public about earthquakes and their potential hazards. (each item in the list below would be a link, either local or distant, to some more information, such as who was involved and what was done.) Earthquake Display at Randall Children's Museum in San Francisco, CA, USA. Teaching Gilroy, CA, USA, students about earthquakes and seismology. Gilroy, CA, USA, school seismograph. .... 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://www.aeic.alaska.edu/lahr http://www.lahr.org/john-jan _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: Balleny Island event posting Date: Wed, 25 Mar 1998 12:47:58 -0700 Arie- That is a beautiful record you posted. What is IDC? -Edward PS. I'll be in Oz next week, but not out West. Arie Verveer wrote: > Hi, The earlier posting of the Balleny island event, displays the > incorrect magnitude and comment. In my rush to post the event, I > used the IDC evaluation. Please change the comment field with the > USGS's data. > > I which to thank Dave Nelson for pointing out the possibility of > interruption errors with the Automated IDC computes. If in the > future an event occurs and the IDC is the only source, I'll place > the words (IDC) in the comment field. This type of thing happens > for small regional events. > > Thanks. > > Arie > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: Balleny Island event posting Date: Wed, 25 Mar 1998 12:04:43 -0700 Edward Cranswick wrote: > > Arie- > That is a beautiful record you posted. What is IDC? Internation Data Center: http://140.162.3.250:65120/ -- ---/---- Charles P. Watson Seismo-Watch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: Outreach Information, #3 - Resources, etc. Date: Wed, 25 Mar 1998 13:09:22 -0700 Steve- Thank you for the summary. I agree with John Lahr that it would be good to keep a record of PSN = outreach activities. Maybe you could put something on your website for s= tarters. I think that all you Bay Area and South Bay PSN people should t= hink about the IRIS meeting in July that will be held in Santa Cruz and w= hich Larry plans to attend. There will be several sessions about Educati= on and Outreach. Also, Ted Blank's idea about having the Almaden School = present a poster at AGU at San Francisco in December is a great idea. -Edward Steve Hammond wrote: > Hi Ed, > > I have some recent examples of how PSN members are reaching out into th= e community which you may want to mention when convincing folks that this= is important. Especially if you are going to talk about supporting the c= ommunity. I'm sure there are more examples and people need to speak up = (like Charlie in Tenn.). > > In conjunction with science awareness, Jan Froom recently spent a few d= ays teaching several classes (with 20 or so students in each one... ) at = a Gilroy school about earthquakes and seismology. He also installed a sei= smic station which is now operational and the teachers/kids maintain with= Jan's help. > > Sam Gazdick and I just finished working on-site with curator John Dilli= on at the Randall Children's Museum in San Francisco. This work is in con= junction with a major display on earthquakes that is due to officially op= en at the Randahll on April the 18th . (I have taken some digital photos = of the display and can email them to you.) Sam did all the work setting u= p a seismograph and thermal chart recorder. The folks at Berkeley are wor= king on a telemeter link to real-time data to be displayed. There is a to= uch screen system running the museum version of Seismic. The USGS has hel= ped with some hands-on fault line displays. Joe Sena of the USGS original= ly started the planning before he retired and moved south. I put togethe= r a donated "Make a quake" display system where kids jump up and down an= d see the trace output on a PC screen simulating an earthquake trace. Thi= s was also a combined PSN effort because Dick Chelberg donated the A/D br= eakout box, Jan Froom donated the IBM DACA card, I > built the pre-amp and setup a PSN donated PC, and Ted Blank reworked EM= ON so that it would never save a file. At the heart of the display, is a = full-size 1906 earthquake building. It was donated and built by the San F= rancisco Carpenters Union. It follows the original plans used to build th= ousands of temporary houses, erected in the city parks following the 1906= earthquake. As a team all these people worked together with Randall cura= tor John Dillon (and others unnamed) to develop a really impressive displ= ay that several thousand children will visit over the next year. > > Regards, Steve Hammond > PSN - San Jose > > Edward Cranswick wrote: > > > Peter- > > I would like to display our poster, > > > > "Public Seismic Network (PSN): a Model for Preparing People > > to use Real-time Information About Natural Hazards" > > > > Edward Cranswick and Benjamin Gardner (U.S. Geological Survey, > > MS 966, Box 25046, Federal Center, Denver, CO 80225, USA; > > 303-273-8609; cranswick@......... > > Public Seismic Network (http://psn.quake.net/, psn-l@.............. > > > > that we presented at the American Geophysical Union meeting in Dec 19= 97 > > at San Francisco. Attached is a copy of the abstract. > > Thank you. > > -Edward > > > > > (1) INTERNAL COMMUNICATIONS - USGS 1998 POSTER REVIEW > > > This 10th almost-annual poster display will take place Thursday, Ap= ril > > > 30, in Building 25, Lecture Halls A&B. Our thanks to everyone who = has > > > offered to display posters here, which have been displayed at other= > > > scientific meetings throughout the past year. We now have about 28= > > > posters promised, and can accommodate up to about 10 more. If you > > > contacted me about displaying a poster, you'll be receiving another= > > > email from me very shortly, with details about submitting an email = or > > > diskette version of your abstract in a standard format. If you hav= en't > > > contacted me yet but are still interested, please send an email. > > > > -- > > 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 (PSN): a Model for Preparing People > > to use Real-time Information About Natural Hazards > > > > Edward Cranswick and Benjamin Gardner (U.S. Geological Survey, > > MS 966, Box 25046, Federal Center, Denver, CO 80225, USA; > > 303-273-8609; cranswick@......... > > Public Seismic Network (http://psn.quake.net/, psn-l@.............. > > > > When an earthquake occurs, unlike any other natural hazard, every ind= ividual in the population at risk is aware within seconds that a dangerou= s event has happened. Without the aid of any technology, the consciousne= ss of everyone affected is almost instantaneously focused on the same sub= ject. Instead of soliciting that information, authorities broadcast the = redundant message that an earthquake has occurred. A program of monitori= ng natural hazards for the public requires public participation to effect= ively mitigate those hazards. The Public Seismic Network (PSN), rather t= han relegating them to the role of sitting ducks waiting to be devastated= by the unexpected, enables people to become aware that earthquakes are p= art of normal, on-going Earth processes. The PSN is a rapidly growing int= ernational group of amateur seismologists, concentrated in California, wh= o record earthquakes with their own digital seismographs and exchange wav= eform 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 w= ebsites. In urban areas of high seismic risk, a grassroots organization = like the PSN -- equipped with low-cost, mass-produced, standardized stron= g-motion seismographs -- could vastly increase the spatial density of sam= pling ground motions. This organization would form a constituency of wel= l-informed residents who not only know how to respond to catastrophic ear= thquakes but also support hazard mitigation programs in the community. R= ather than just building faster ambulances to mitigate the impact of hear= t attacks, it is more effective to modify the public habits of exercise a= nd diet. The PSN is a model for using technology to connect human awaren= ess to, rather than shield it from, the environment. > > > > AN: U51A-05 > > LO: MC HALL D > > HR: 0830h > > DA: Friday > > TI: Public Seismic Network (PSN): A Model for Preparing People > > to Use Real-Time Information About Natural Hazards > > AU: *E Cranswick, B Gardner > > MN: Fall Meeting 1997 > > _____________________________________________________________________ > > 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: ralvarez@........ (Raul Alvarez) Subject: Re: STM-8 design question Date: Wed, 25 Mar 1998 17:36:12 -0700 (MST) A more rigid boom >would address these problems, if it can be kept lightweight. > >Regards, >Sean-Thomas > Sean, Could you address the reason to maintain the boom weight low? I have begun work on an STM-8, but will be using a much larger voice coil/magnet salvaged from a main frame harddrive. I seperated the magnets from the frame, and turned the outer and inner parts of the frame so that there would be a greater gap distance. Then replaced the magnets. The coil is made from 2"ABS pipe turned to form a bobbin for a custom wound coil. Work is going slow, but what has been built is looking good. 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! ~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: boom weight Date: Wed, 25 Mar 1998 21:33:09 -0600 (CST) Raul; Here is a response to a similar question that I had saved: There is no magic ratio of boom mass wrt main mass. Technically, since we have hinged suspensions, we all have rotational systems, and should be figuring rotational angles and torqes about the hinge, etc. (Fortunatley our displacements and therefore our angles are very small, so we can consider our sensors as simple translational systems, and pick a handy reference point, like the center of the main transducer. The closer that the center of mass of the boom + main mass is to that point, the better our approximations are.) Considering the torques about the hinge: the main mass exerts L*M, where L is the boom length. The boom exerts 0.5*L*B, if the Cm(b) of the boom mass B is at the center of L. So the total torque about the hinge is (L*M + 0.5*L*B) or L*(M + 0.5*B). So if we pick M=450gm and B=100gm (about what the Beta sensor here has), we have a torque of L*500 gm. But this is equivalent to the angular momentum of the whole boom + mass system, wrt its' center of mass, (as if all the mass were at the Cm.) So: Cm * (450 + 100) = L * 500, or Cm = 0.91*L. So theoretically we should have the transducers at 91% of the boom length from the hinge for this example. Fortunately, it is not a big care unless/ until we want to nail the fit to the transfer function to better than 10%. I determine the effective mass by leveling the boom and then removing the mass, coil, balance weights, etc, and then stacking up brass test weights above the center of the force coil until it is again balanced; then I total up the test weights. I hope this answers your question. Regarding using the large magnet (and coil) from a big old hard drive, it would be worth doing a preliminary check of the force constant to see if it is strong enough, especially if you have modified it for a larger annular gap, which greatly decreases the field strength. The drive head actuator is meant to be linear over a long range, rather than intense over a short range like we need, and get in a stereo speaker. You can make a simple balance with a ruler and your coil, fitted to work in the magnet. If you add a small weight, like 10 grams to unbalance it, then measure the current (like 10 ma) in the coil it takes to restore the balance (you will have set up the coil leads for this), the constant is then (10gm * g)/10ma, or 9.8 Newtons/Ampere, which is about the minumum I would expect to work with a 0.5kg mass. Commercial VBB sensors have two to ten times this value of force constant. Regards, Sean-Thomas. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: Barometric Pressure Change Sealed Seismo Container Date: Wed, 25 Mar 1998 21:53:08 -0600 (CST) Bob, If someone does the calculations of PVT for a sealed container, you find that the pressure change for something like 10 deg C is quite small wrt a storm front with a barometer drop of 1/2 inch (= 1/4 psi). Generally other thermal problems with the sensor are more serious. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: Re: A Vacuum tight, but not evacuated container Date: Wed, 25 Mar 1998 22:07:45 -0600 (CST) Meredith, Barometric noise has been a tough problem to beat. Even the NBS tiltmeters in borehole pipes had to be refitted with 3" thick end caps (that they were mounted to) to stop the problem. For a seismometer, flexing of the base that the sensor is attached to (or is between the seis and the pier) is the biggest problem. A cylindrical cover over a thick circular base can be isolated with large O rings to keep distortions of the cover from the base. Otherwise, the contaiment should lengthen the time constant of the pressure inside the case to something like several hours to reduce wind pressure noise, which is of the order of 1 to 10 minutes. This puts the remaining noise well outside the passband of the instrument. Without a contaiment, my Beta instrument is pretty useless when the wind is enough to ring the wind chimes on the back porch. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Al Allworth" Subject: Re: A Vacuum tight, but not evacuated container Date: Wed, 25 Mar 1998 20:36:02 -0800 -----Original Message----- From: S-T Morrissey To: psn-l@............. Date: Wednesday, March 25, 1998 8:09 PM Subject: Re: A Vacuum tight, but not evacuated container What is the atmosphere inside the L4 seismometer? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Arie Verveer Subject: Antarctic Ice shelf. Date: Thu, 26 Mar 1998 20:26:16 +0800 Hi, If the "greenhouse" effect has a warming trend on the Antarctic region will the very slow melting of the continental ice cause a rebound effect on the Lithosphere in that region. Thus triggering more activity at the Antarctic plate boundary. Would this be a justifiable measure of the greenhose effect? Just a thought after the "Balleny" event. Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Liberio Rossi" Subject: Central Italy big event Date: Thu, 26 Mar 1998 16:59:39 +0100 Event of M= 4.6 Recorded at Lat.43°54'79 long. 10°31'56 Liberio Rossi liberio.rossi@........ From: Robert L Barns <75612.2635@..............> Subject: 'Quake ident? Date: Thu, 26 Mar 1998 12:03:42 -0500 Hi gang, I recorded a event which I cannot identify in either the CDIDC = or CNSS lists. = It's shape is completely typical of a distant 'quake. It was above my noise level for at least 3 hours and gave a p-p count of 33,000 in SDR. = The signal-to-noise ratio was 33000/80. It started here at 3:32 UTC on 3/25. The surface waves started at about= 4:35 UTC. I will try to send it to the PSN archives, evetn@............. (file 980325A.RB1). What could it be??? Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Canie Brooks Subject: Re: 'Quake ident? Date: Thu, 26 Mar 1998 09:17:38 -0800 Take a look here: http://seismo.ethz.ch/redpuma/redpuma_ami_list.html At 12:03 PM 3/26/98 -0500, Robert L Barns wrote: >Hi gang, > I recorded a event which I cannot identify in either the CDIDC or >CNSS lists. > It's shape is completely typical of a distant 'quake. It was above my >noise level for at least 3 hours and gave a p-p count of 33,000 in SDR. >The signal-to-noise ratio was 33000/80. > It started here at 3:32 UTC on 3/25. The surface waves started at about >4:35 UTC. > I will try to send it to the PSN archives, evetn@............. (file >980325A.RB1). > What could it be??? >Bob Barns > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Dewayne Hill Subject: http://wwwneic.cr.usgs.gov/neis/finger/quake Date: Thu, 26 Mar 1998 12:30:21 +0000 It appears that http://wwwneic.cr.usgs.gov/neis/finger/quake is no longer being used for the near real time list. Can someone tell me where it has moved to. -- Dewayne (n0ssy) & Linda (n0uqf) Hill Westminster, Colorado USA 39.83569n 105.06270w. Elev 5660ft. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: http://wwwneic.cr.usgs.gov/neis/finger/quake Date: Thu, 26 Mar 1998 11:35:32 -0700 I have a number of alternatives here: http://www.seismo-watch.com/EQSERVICES/CurrentActivity/CurrentActivity.html -- ---/---- Charles P. Watson Seismo-Watch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Francesco" Subject: BIG QUAKE IN CENTRAL ITALY Date: Thu, 26 Mar 1998 20:42:00 +0100 16.29.09 UTC MB 5.4 43.10 N 12.70 E Some material damnages My station is 60 km E from epicenter Later i will post my sismogram Francesco Nucera - Osimo, Italy -
16.29.09 UTC    MB=20 5.4     43.10 N  12.70 E
 
Some material damnages
 
My station is 60 km E from=20 epicenter
 
Later i will post my = sismogram
 
Francesco Nucera   - = Osimo, Italy=20 -
From: lahr@.................. Subject: Re: http://wwwneic.cr.usgs.gov/neis/finger/quake Date: Thu, 26 Mar 1998 13:01:19 -0700 (MST) > From: Dewayne Hill > > It appears that http://wwwneic.cr.usgs.gov/neis/finger/quake is no > longer being used for the near real time list. Can someone tell me > where it has moved to. > -- > > Dewayne (n0ssy) & Linda (n0uqf) Hill Dewayne, I tried it just now and it worked for me. Maybe there is an internet problem somewhere. JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Dewayne Hill Subject: Re: http://wwwneic.cr.usgs.gov/neis/finger/quake Date: Thu, 26 Mar 1998 13:23:44 +0000 Thanks to Charles and John for your responce. I see that the file is now being updated. There was a glitch somewhere that is now cleared. Dewayne Hill wrote: > > -------------------------------------------------------------------------- > Your following message has been delivered to the 271 members of > the list psn-l@............. at 11:28:44 on 26 Mar 1998. > -------------------------------------------------------------------------- > > It appears that http://wwwneic.cr.usgs.gov/neis/finger/quake is no > longer being used for the near real time list. Can someone tell me > where it has moved to. > -- > > Dewayne (n0ssy) & Linda (n0uqf) Hill > Westminster, Colorado USA > 39.83569n 105.06270w. Elev 5660ft. > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L -- Dewayne (n0ssy) & Linda (n0uqf) Hill Westminster, Colorado USA 39.83569n 105.06270w. Elev 5660ft. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Giovanni Rotta" Subject: INTERMEDIATE QUAKE IN CENTRAL ITALY 16:27 UTC Ml. 5.1 Date: Thu, 26 Mar 1998 22:39:21 +0100 Hi alla We have an intermediate quake this afternoon in Central16:27 UTC Ml. 5.1 See file. Regards, Giovanni Giovanni Rotta rottag@.......... Via F. Pizzigoni, 10 33010 Resia (Udine) Italy Lat. 46.373N Long. 13.305E QTH Locator JN66PI From: Larry Cochrane Subject: Sending attachments to the PSN-L list. PLEASE READ Date: Thu, 26 Mar 1998 13:55:33 -0800 Hi Everyone, Not to pick on Giovanni... but this is a good time to remind everyone that you should NOT send attachments to the PSN-L list. If you have an event file please send it to the event@............. (or event@.............. but not both!) email address. This way your event file will get archived on my system and sent out to the NewEvent or NewFile (notification only) mailing lists. Thanks, -Larry Cochrane Redwood City, PSN At 10:39 PM 3/26/98 +0100, Giovanni Rotta wrote: >Hi alla >We have an intermediate quake this afternoon in Central16:27 UTC Ml. 5.1 >See file. >Regards, >Giovanni > >Giovanni Rotta >rottag@.......... >Via F. Pizzigoni, 10 >33010 Resia (Udine) Italy >Lat. 46.373N Long. 13.305E >QTH Locator JN66PI >Attachment Converted: "C:\NET\NEW\980326c.gr1" > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: 'Quake ident? Date: Fri, 27 Mar 1998 10:35:18 +1200 At 12:03 PM 3/26/98 -0500, you wrote: >Hi gang, > I recorded a event which I cannot identify in either the CDIDC or >CNSS lists. > It's shape is completely typical of a distant 'quake. It was above my >noise level for at least 3 hours and gave a p-p count of 33,000 in SDR. >The signal-to-noise ratio was 33000/80. > It started here at 3:32 UTC on 3/25. The surface waves started at about >4:35 UTC. > I will try to send it to the PSN archives, evetn@............. (file >980325A.RB1). > What could it be??? >Bob Barns > Bob, the time coincides with the M8 from antartica ur P arrival at 03:32:05 UTC and the quake OT 03:12:30 means a P travel time of ~ 19 1/2 odd minutes. have u not been around for the last few days with all the e-mail flying back and forward abt this event ??. well done great record 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: S-T Morrissey Subject: Inside L4-C Date: Thu, 26 Mar 1998 18:50:27 -0600 (CST) The L4-C, as with most seismometers, should be full of air, unless it has been abused, then you can usually find water, spiders, assorted dirt and debris, etc, all of which soak up any potential earthquake data, since the latter is generally only compatible with plain dry air. Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: zero length spring Date: Thu, 26 Mar 1998 20:35:26 -0600 (CST) Barry, You are right in observing that a stiff spring has a high mechanical frequency. But an ordinary low-stiffness spring cannot support a reasonable mass. Hence the zero-length design, like in the large long-period seismometer, where the large coil spring takes 45 pounds just to open it, and 60 pounds of tension to reach the "zero length", where the mechanical period is about 1 second (how it oscillates hanging vertically with a 60 lb weight attached). When installed in the LP seis at a 30 deg angle, the seis can have periods up to 60 seconds. Note that the zero-length behavior occurs over a rather limited range of extension, which is determined by careful testing. I had a previous description on this subject that may help: Regarding "zero length" behavior of a spring. For an ordinary spring, as it it stretched, the change in length is proportional to the force applied. If you attach a linear dial an put it in a box and step on it, it will tell you how well you prospered fron the holiday feasting. ie Hooks law: F = k *(l - lo), where k is the spring constant (force/unit length), l is the length with the force F applied, and lo is the initial length. When such a spring is used in a vertical seismometer, this means that the restoring force changes as the boom moves, making the sensor non-linear. This was solved in the 30s by the LaCoste suspension that devised a spring such that at a specific length the change in force with change in length became zero. That is, if lo = 0, so F = k*l, then F is constant at some l. So any minute acceleration will move the mass in a linear fashion. So when such a spring is made, namely by twisting the wire (or quartz fiber in gravimeters) as the coil is wound, the spring ends up forcibly closed: it takes an initial force to open it. I won't go into the math to determine the constants, but at some opened length, lo becomes 0. With the leaf spring I use, this occurs at about a 5" opening, and is evident when the spring is installed and the opening adjusted. At one point, the boom will not stay balanced, but floats either up or down with instability (aka an infinite period). So I increase the opening slightly, and the period becomes stable. A stable period is essential for a well defined transfer function. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: barry lotz Subject: Re: zero length spring Date: Thu, 26 Mar 1998 20:01:00 -0800 Sean Thomas I appreciate your explanation. I don't mean to be argumentative or thick but I thought the general linear equation of motion was: P(t)=M*(acceleration)+C*(velocity)+K*(change in position) It seems ,with a spring(for small deflections), the force applied is a linear function of the deflection like any other material(Youngs modulus) I thought the steady state condition fell out of the equation.ie gravity was balanced with K*(initial length). I'll continue to ponder your explanation. Thanks again. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: bschafer@......... Subject: radio frequencies? Date: Thu, 26 Mar 1998 23:39:45 -0600 (CST) Hi, I am new to the list and I do have a question. Is there a radio frequency that I can tune to to hear seismic activity? I am blind so a seismograph wouldn't be of much use to me. There used to be a radio frequency--162.810--that used to emit a steady sound when there were no quakes in progress. When there was a tremor the tone would become more high pitched--the hier the larger the quake. Thanks for any information on this. Bonnie the crafty crafter _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: David Josephson Subject: Re: radio frequencies? Date: Thu, 26 Mar 1998 23:15:55 -0800 (PST) Bonnie the crafty crafter writes > Hi, I am new to the list and I do have a question. Is there a radio > frequency that I can tune to to hear seismic activity? I am blind so a > seismograph wouldn't be of much use to me. There used to be a radio > frequency--162.810--that used to emit a steady sound when there were no > quakes in progress. When there was a tremor the tone would become more > high pitched--the hier the larger the quake. This has been discussed a lot on this list, but not recently. There is a whole bunch of radio frequencies around California that the USGS and other seismic networks use to carry seismometer data from the various sensor locations back to a central place (Menlo Park and Berkeley are the main ones in the north) where they are analyzed. Each radio frequency carries at least one tone, which is steady if there is no movement and wobbles up and down in pitch in step with the ground acceleration at the sensor site. These signals are in the VHF high band around 162 MHz but are rather weak and have directional antennas, intended for point-to-point links back to the data center. If you happen to be in line with one of these paths, an ordinary scanner is enough to pick up the signals. Larry Cochrane, host of this list, has made a demodulator board available that works with any of the standard USGS tones. -- David Josephson / Josephson Engineering / San Jose CA / david@............. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: radio frequencies? Date: Fri, 27 Mar 1998 00:16:33 -0800 (PST) >This has been discussed a lot on this list, but not recently. There is a >whole bunch of radio frequencies around California that the USGS and >other seismic networks use to carry seismometer data from the various >sensor locations back to a central place (Menlo Park and Berkeley are >the main ones in the north) where they are analyzed. Each radio frequency >carries at least one tone, which is steady if there is no movement and >wobbles up and down in pitch in step with the ground acceleration at >the sensor site. These signals are in the VHF high band around 162 MHz >but are rather weak and have directional antennas, intended for point-to-point >links back to the data center. If you happen to be in line with one of these >paths, an ordinary scanner is enough to pick up the signals. > >Larry Cochrane, host of this list, has made a demodulator board available >that works with any of the standard USGS tones. > >-- >David Josephson / Josephson Engineering / San Jose CA / david@............. > >_____________________________________________________________________ > As an interesting note: I was monitoring one of those sites using a VHF scanner with the audio output connected to the input of a frequency selective voltmeter and it's tracking generator output viewed on an oscilloscope while there was an M5.3 aftershock from the Northridge Earthquake. Needless to say, that combination of test equipment was very impressive to view and listen to! Frank Condon mailto:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Norman Davis WB6SHI Subject: Re: radio frequencies? Date: Fri, 27 Mar 1998 06:38:02 >Bonnie Where are you located? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: lahr@.................. Subject: Re: zero length spring Date: Fri, 27 Mar 1998 09:17:07 -0700 (MST) Barry, There is a good web page describing the zero length spring: http://www.lacosteromberg.com/uwman3a.html#zero which goes into the mathematics. A zero length spring would not have infinite period if it were held vertically with a mass hanging from it. It does have an infinite period if the spring is attached from a vertical post diagonally to a horizontal boom. The torque on the boom is not just a function of the extension of the spring but also of the angle between the boom and the spring. (if the boom were rotated down to become vertical, there would be no torque). The torque produced by gravity on the mass is also a function of the orientation of the boom. La Cost figured out how to make a spring/boom system that would be stable in any position. This would be equivalent to a swinging-gate horizontal that is not tilted; the gate would stay where ever you put it. Of course in seismology we want a long but not infinite period, so the gate must be tilted slightly and the zero-length spring should not be exactly "zero" in length. Hope this helps, JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Edward Cranswick Subject: Re: travel time Date: Fri, 27 Mar 1998 11:16:45 -0700 Stephen- I cannot tell a lie. After I posted that message, John Lahr came down and helped me use the Travel Time Calculator again. We discovered that the Northern California catalog I had selected, like many of the other catalogs, only kept the last few days of seismicity. When I changed to the NEIC 30-day catalog, I found the event. Thanks for your response. -Edward Stephen & Kathy wrote: > > Hi Edward, > I had some fun the first few times that I tried the calcultor also. > You probably have it figured out by now but just in case you don't,, > The reason you didn't get any data was because there were no EQ. 5 > or larger on the list. Try changing the 5 to a 3 and see if that > gives you some data. > Stephen > Pilot Hill Ca. -- 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: JHammes@......................... Subject: Date: Fri, 27 Mar 1998 10:15:35 -0800 For you folks interested in large motion stuff, there is a new dual axis, +/- 2g sensor chip w/ 5 milli-g resolution from Analog. See it at: http://www.analog.com/iMEMS/products/ADXL202.html jerry hammes jhammes@.......... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Francesco" Subject: NEW PSN ITALY WEB SITE Date: Fri, 27 Mar 1998 22:08:50 +0100 Hi guys. From today is available on net our new web site: PSN ITALY - I.E.S.N. at http://space.tin.it/scienza/frnucer=20 The best regards=20 Francesco Nucera Roberto Pozzo Claudio Conti Giovanni Rotta Liberio Rossi Paolo Frediani Alessandro Arrighi from Italy!
Hi guys.
 
From today is available on net our = new web site:=20 PSN ITALY - I.E.S.N. at
http://space.tin.it/scienza/= frnucer=20
 
The best regards
Francesco Nucera
Roberto Pozzo
Claudio Conti
Giovanni Rotta
Liberio Rossi
Paolo Frediani
Alessandro=20 Arrighi       from=20 Italy!
From: meredith lamb Subject: Re: NEW PSN ITALY WEB SITE Date: Fri, 27 Mar 1998 15:45:38 -0700 Francesco wrote: > Hi guys. From today is available on net our new web site: PSN ITALY - > I.E.S.N. athttp://space.tin.it/scienza/frnucer The best > regardsFrancesco NuceraRoberto PozzoClaudio ContiGiovanni RottaLiberio > RossiPaolo FredianiAlessandro Arrighi from Italy! Congratulations on your new web site. It seems to be be extensive and a joy to check out. Well done fellows! I was inpressed. Meredith Lamb  

Francesco wrote:

 Hi guys. From today is available on net our new web site: PSN ITALY - I.E.S.N. athttp://space.tin.it/scienza/frnucer The best regardsFrancesco NuceraRoberto PozzoClaudio ContiGiovanni RottaLiberio RossiPaolo FredianiAlessand ro Arrighi       from Italy!
 Congratulations on your new web site.  It seems to be be
extensive and a joy to check out.  Well done fellows!  I
was inpressed.

Meredith Lamb
 
  From: psn.list@.................... (Psn List) Subject: CDMG Seismological Instrument Tech Exams Date: Fri, 27 Mar 1998 22:28:00 GMT From: Edward Cranswick Subject: Re: NEW PSN ITALY WEB SITE Date: Fri, 27 Mar 1998 19:48:55 -0700 Dear Italian Colleagues and other PSN members- I just checked out the webpage of the I.E.S.N., Italian Experimental Seismic Network, i.e., the Italian PSN, and I am very impressed. The pictures of stations give a sense of place. The dual language versions, Italian/English, is a an excellent reminder of what an easy life we Americans enjoy: we must invent language problems with each other in the form of incompatible computer data formats. Perhaps now that the Italian PSN has become so organized, your seismicity will now decrease. Congratulations! -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: TESMECO Subject: Re: radio frequencies? Date: Fri, 27 Mar 1998 22:37:48 EST i monitor the tones .it is great to hear or satisfy the some times was that an earthquake or a truck i turn to the scanner it is allways there just like the heart beat of the earth seeya _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: Possible Household Barometric Sealed containers Date: Fri, 27 Mar 1998 23:17:28 -0700 Can't see the tree because of all the forest thing............ STM-8 container: 5 gallon toilet water tank with the lid It seems possible to use this with a rubber/silicone seal with the lid as the base or top lid. The holes can be plugged or used as signal/power ports. Ours measures ~ 20" length X slightly over 6" wide. It has 3 holes that shouldn't be too hard to plug or utilize. Heavy things, maybe better to set the base down and form a setting on wet concrete. The lid would be on top and may need a strap down of some sort. Difficult to adjust the seismo by hand, I would imagine. With the tank on top it would be easier to adjust the seismo. Probably alot of these around. Low temperature coefficient compared to metals. Another more remote possibility; a deep basin kitchen sink, with a reasonable flat upper edge surface. They come in ceramic (a sealed unit), and cast iron (a more real vacuum candidate). Rubber/silicone seals also. You would need a base plate of course. I would think the cast iron opening could be used and hold signal terminals etc., with perhaps a weld. Ours measures ~ 20" wide X 14" X 7" depth. The top edge is fairly flat, but the faucet handle side looks like it may need more rubber/silicone fill than the other sides. I guess there is plastic versions around also. Besides the dimensions, the top edge must be as flat as possible. Another candidate would be a laundry wash basin as a sealed container candidate but of course it would need a base. The ceramic and cast iron can be very heavy of course, but the weight may come in handy for the seal part. Throwing ideas around......forget the bath tub - ha. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Charles R. Patton" Subject: Re: Possible Household Barometric Sealed containers Date: Sat, 28 Mar 1998 09:52:56 -0800 With regard to making the RTV/beeswax seal as described by Roger Baker last week. When you get to your "bathtub" sizes you may find it a bit hard to warm it up to do the beeswax smear. Don't forget that beeswax is easily dissolved with a fast evaporating solvent such as MEK or acetone. Just make a syrupy solution and wipe on the edge to become the seal lip. No heat necessary. Charles R. Patton, Editor, Geo-Monitor _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Antarctic Ice shelf. Date: Sat, 28 Mar 1998 11:12:25 -0800 (PST) Hi all: I might add that the largest volcano in the world is located under the ice-cap of Antarctica. Mt. Eurebus, if it should decide to become active, "it would cause the ice-cap to melt and raise the sea level by a couple hundred feet." Does anyone know if this M7.9 event is in any way connected with a renewal of volcanic activity on the continent of Antarctica? Thanks, Frank Condon mailto:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" >Hi, If the "greenhouse" effect has a warming trend on the Antarctic >region will the very slow melting of the continental ice cause a rebound >effect on the Lithosphere in that region. Thus triggering more activity >at the Antarctic plate boundary. Would this be a justifiable measure >of the greenhose effect? Just a thought after the "Balleny" event. > >Arie > > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Ice Quakes! Date: Sat, 28 Mar 1998 11:54:51 -0800 (PST) Hi all: Well, it's new to me. So, I hope at least some of you might be interested in this URL for information about ice quakes: http://griffy.nmt.edu/Geop/Erebus/erebusfigs/ice.html Frank Condon mailto:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Antarctic Ice shelf. Date: Sat, 28 Mar 1998 11:56:19 -0800 (PST) Hi all: Here is the URL for an interesting view of the Mt. Erebus volcano on Antarctica. http://volcano.und.nodak.edu/vwdocs/current_volcs/erebus/erebus.html Frank Condon mailto:frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" >-------------------------------------------------------------------------- >Your following message has been delivered to the 273 members of > the list psn-l@............. at 11:11:38 on 28 Mar 1998. >-------------------------------------------------------------------------- > > >Hi all: >I might add that the largest volcano in the world is located under the ice-cap >of Antarctica. Mt. Eurebus, if it should decide to become active, "it would >cause the ice-cap to melt and raise the sea level by a couple hundred feet." >Does anyone know if this M7.9 event is in any way connected with a renewal >of volcanic activity on the continent of Antarctica? > >Thanks, > >Frank Condon >mailto:frankcnd@.......... >"Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" > >>Hi, If the "greenhouse" effect has a warming trend on the Antarctic >>region will the very slow melting of the continental ice cause a rebound >>effect on the Lithosphere in that region. Thus triggering more activity >>at the Antarctic plate boundary. Would this be a justifiable measure >>of the greenhose effect? Just a thought after the "Balleny" event. >> >>Arie >> >> >> >> >>_____________________________________________________________________ >> >>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: Jim Hannon Subject: Re: Seismic Prediction Group Date: Sat, 28 Mar 1998 21:39:11 -0600 Frank Condon wrote: > > Hello All: > Here is an interesting URL for a group that is interested in predicting > earthquakes. > > http://www.btinternet.com/~seismoprediction/ > > Frank Condon > mailto:frankcnd@.......... > "Located in the seismic corridor somewhere between fontana & Mammoth Lakes" > It is interesting also that I tried contacting this group by email and have received no response. Also their "apply for membership web form" seems try and access a nonexistent cgi program.(it doesn't work) -- Jim Hannon http://soli.inav.net/~jmhannon/ 42,11.90N 91,39.26W WB0TXL _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Chuck Erickson Subject: Books to get me started Date: Sat, 28 Mar 1998 19:55:19 -0800 I am a newcomer to this list and a worse than rank amateur at seismology. I wanted to get some good introductory texts and ordered Earthquakes and Geological Discovery (Scientific American Library, Vol 46) Bruce A. Bolt / Published 1993 from Amazon. They now tell me that the book is not available. Does anyone have a copy they would be interested in selling me? Also, I found the following texts that might be OK for a new student. If anyone has read either one and would like to give me some feedback I will be very grateful. Seismology - H. A. Doyle, et al / Published 1996 Modern Global Seismology (International Geophysics Series, Vol 58) Thorne Lay, Terry C. Wallace / Published 1995 Thanks for your help, Chuck Erickson - Saratoga, CA mailto:cee@............. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: John Hernlund Subject: Re: Books to get me started Date: Sat, 28 Mar 1998 21:28:02 -0700 (MST) On Sat, 28 Mar 1998, Chuck Erickson wrote: > Seismology - H. A. Doyle, et al / Published 1996 This is an easier book for beginners, however it all depends on how good your math skills are... > Modern Global Seismology (International Geophysics Series, Vol 58) > Thorne Lay, Terry C. Wallace / Published 1995 This is my favorite seismology book. It gives you almost every aspect in a nice logical form, but make sure your math skills are up to par (differential equations, linear algebra, tensor algebra)... ****************************************************************************** John Hernlund E-mail: hernlund@....... WWW: http://www.mc.maricopa.edu/academic/phy_sci/Geology/hernlund/ http://www.public.asu.edu/~hernlund/ ****************************************************************************** _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: sealing containers Date: Sat, 28 Mar 1998 23:16:32 -0600 (CST) To: psn-l@.............. psn-l@.............. Subject: sealing containers Meredith, Charles, and co. Over the years I have found that RTV (silicon) sealants are particularly handy for making good temporary seals of containers because , while it makes a good long-lived seal, if the container needs to be opened, it readily peals away from most smooth surfaces like tupperware type containers, or can be cleanly cut away with a knife or exacto blade. THis is especially useful when I seal radio transmitters and electronics in plastic storage containers that have to be opened every few years to renew the desiccant. I like to avoid sealing materials that remain tacky or gooy over time, because they usually get transferred to everything else in sight. A notable shortcoming of such is that they collect dirt and debris in the seal area, requiring cleaning if the seal is to be renewed. For a large gasketed seal, McMaster Supply sells an "O" ring kit that lets you make seals of many sizes, as well as a wide variety if neoprene, etc, channel gaskets. For some applications, like sliding "O" rings, common vaseline is a useful sealant. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Arie Verveer Subject: Epicentre Location Date: Sun, 29 Mar 1998 14:04:13 +0800 Hi, As suggested before, its possible to use the shareware program "Mapit" to plot at least two sets of distance data to locate an epicentre. By using Dave Nelsons and my data for the recent Loyalty island event the following solution of two solutions were found. Epicentre solutions "1" 23.2 South by 172.7 East. Real Epicentre 23.0 South by 172.4 East Difference 0.2 Degrees by 0.3 degrees I find this an amazing result that's well worth exploring in the future. Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Arie Verveer Subject: Re: Antartic ice shelf Date: Sun, 29 Mar 1998 14:30:25 +0800 Hi, In Larry's FTP site: ftp://psn.quake.net/incoming/ I've placed an image file called "Earth.Jpg". It shows the real height of the earth surface referenced to geoid height. You can easily see a 25 meter depression near the south pole, that maybe due to the weight of the ice. Check out the area near the Ms 7.9 balleny event. Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: bschafer@......... Subject: cee@............. Date: Sun, 29 Mar 1998 01:40:45 -0600 (CST) Books to get me started Hi, I am interested in seismology too but have read very little because some of that stuff just isn't available in braille. However, there is one book written by Charles Richter that is supposed to be for the beginner. I can't, unfortunately, remember the name of it at the moment. I believe it is out of print so will probably have to be gotten from the library. Hope this helps. Bonnie the crafty crafter _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: meredith lamb Subject: STM-8 Seis Remote Centering Thought Diversions Date: Sun, 29 Mar 1998 00:44:18 -0700 Sean-Thomas, With reference to the STM-8 in a sealed container: You've mentioned acouple of centering methods in past messages. The toy motor driving a screw rod and weight and a manuel push pull rod mechanical approach. I can imagine a variety of ways and means with various motors...however of course, your seis MAY, have to use the hinges as a part of the "wiring" to such devices because of current demands....if a model was made for a sealed container. The motor would have to be postioned at the back of the boom because of the magnetic influence. The placement of the motor may cause a seis re-design simply because of its weight. Such a model would have to incorporate some way or material for electrical insulation for the hinges. I imagine that with a good "choice" or "choices" of the angle aluminum replacement or such, that all 4 hinges would do away with the normal small gauge wire for the signal to the coil, and deliver power to the centering device. But then, there maybe associated problems with this approach. Outside of a overhaul of the hinge angle supports, one way I can think of centering the seismo, is by having a DC geared down motor device attached to the mast with a frame pulley type construction. On the string or wire there could be a object which could be centered in a slot on the boom counterweight. Activation one way or another could push or pull the counterweight. After centering the the "drag" object itself could be centered in the counterweight slot, for a "no contact" condition. Speculating of course...you probably have other ideas I'am sure. Thanks, Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: cee@............. Date: Sun, 29 Mar 1998 02:31:36 -0800 (PST) >Books to get me started > >Hi, I am interested in seismology too but have read very little because >some of that stuff just isn't available in braille. However, there is >one book written by Charles Richter that is supposed to be for the >beginner. I can't, unfortunately, remember the name of it at the >moment. I believe it is out of print so will probably have to be gotten >from the library. > >Hope this helps. > > >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 > > Hi Bonnie: "Elementary Seismology" by Charles F. Richter; It's hard to find! I've been trying to get a hold of a copy from Amazon Books for about a couple of months. Also, I've heard that it can be expensive if you can even find a good used copy. It was mentioned once that someone paid $150.00 for it. A good book can be tough to find, even at that kind of a price. Now, I didn't think of looking at the library for it. Well, good luck and just maybe someone out there will know of a good source for cheap used seismological books. Frank Condon frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: More books Date: Sun, 29 Mar 1998 10:46:20 +0000 Hi, For those looking for books on seismology, here's a few more you may care to look out for....... Richter's book, 'Elementary Seismology', published in the 50's...not sure who published it, but it's a wonderful book. B. Howell's, 'Introduction to Geophysics', pub. byMcGraw in1959. This is also a great book to have, having sections on all aspects, including gravity etc. I found a copy recently in a second hand book shop in GB for 5 pounds ($8). G.A. Eiby's, 'Earthquakes'. pub by Heinemann in 1980. Altho' not too technical, it does have some photo's of older professional seismo's (Press Ewing ;Willmore. etc). All above are now out of print, but second hand book shops are worth browsing, also reference libraries etc. in USA will have copies of some/all of above. Also keep an eye on books for sale in USA at..... http:www.geosciencebooks.com/catalogue.html Hope this helps, and happy book hunting ! Regards, Albert Noble (England). _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: sealing containers Date: Sun, 29 Mar 1998 02:52:36 -0800 (PST) Hi Sean: I use electronics grade white or clear RTV for sealing the slugs of adjustable coils where I work. It applies easily, and afterwards we temperature test our equipment from -40 thru 160 degrees F. and see no problems with it. The clear grade that we use is a little bit runny at ambient. But, it is much easier to remove than the white type is. Off the top of my head, I can't remember what the technical difference is between them, except that the white grade is like glue being applied onto everything we use it with, and you need to use an Exacto knife to remove it. At times, it can take a while to get it off. Also, it makes a great silicone rubber foot if you place a drop under each bottom corner of a project case and let it cure overnight. Frank Condon frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" >To: psn-l@.............. psn-l@.............. >Subject: sealing containers > >Meredith, Charles, and co. > >Over the years I have found that RTV (silicon) sealants are particularly >handy for making good temporary seals of containers because , while it >makes a good long-lived seal, if the container needs to be opened, it readily >peals away from most smooth surfaces like tupperware type containers, >or can be cleanly cut away with a knife or exacto blade. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Antartic ice shelf Date: Sun, 29 Mar 1998 02:59:13 -0800 (PST) Hi Arie: I downloaded and viewed the geoid picture. I see that the area near the epicenter is below average by 40 meters. I couldn't tell if it was under an ice-cap or not. But, according to the theory it certainly looks promising. Do you think that the weight of the ice above the epicenter might have caused the earthquake? Frank Condon frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" >Hi, In Larry's FTP site: ftp://psn.quake.net/incoming/ >I've placed an image file called "Earth.Jpg". It shows the real height >of the earth surface referenced to geoid height. You can easily see a >25 meter depression near the south pole, that maybe due to the weight >of the ice. Check out the area near the Ms 7.9 balleny event. > >Arie > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: prewar Subject: Re: More books CORRECTION Date: Sun, 29 Mar 1998 11:16:17 +0000 prewar wrote: > Hi, > For those looking for books on seismology, here's a few > more you may care to look out for....... > > > Also keep an eye on books for sale in USA at..... > http:www.geosciencebooks.com/catalogue.html > Hi again! Sorry, GB spelling of 'catalogue'etc. is different to USA!! (When are we going to speak the same language? ) Correct site is http://www.geosciencebooks.com/catalog.html This web site may have been mentioned on PSN before. Regards Albert Noble (England).  

prewar wrote:

Hi,
For those looking for books on seismology, here's a few
more you may care to look out for.......
 

Also keep an eye on books for sale in USA at.....
http:www.geosciencebooks.com/catalogue.html
 

Hi again!

Sorry, GB spelling of 'catalogue'etc.  is different to USA!!
(When are we going to speak the same language? <g>)

Correct site  is http://www.geosciencebooks.com/catalog.html

This web site may have been mentioned on PSN before.

Regards

Albert Noble (England). From: "Charles R. Patton" Subject: Re: sealing containers Date: Sun, 29 Mar 1998 11:04:32 -0800 Hi Frank, You wrote: >...I can't remember what the technical difference is between > them... I'm not sure if your question is the difference between the white and clear grades of silicone, or the difference between the electronics grade and the normal. In the latter case, the difference between the electronics and normal is the cure mechanism. In regular silicones, the cure agent is H2O (water vapor) and acetic acid which is why you smell the vinegar smell when you use these varieties. In the electronics grade, the agent is alcohol (methanol?) and H2O, and as a consequence the electronics grade is less likely to cause cause corrosion. My experience some 20 years ago was that the acetic acid varieties bond more aggressively and cure quicker, but they may not be true any more. A corollary of the above is to note that silicones are not really waterproof, as evidenced by the fact that they need water vapor to migrate to cure. Their claim to fame is that they are very pure, and don't allow ions to migrate, which is why they were used as integrated circuit die coverings for so long. Regards. Charles R. Patton, Editor, Geo-Monitor _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: peaches@............ (Donna Whitaker) Subject: Large Event Comming In Date: Sun, 29 Mar 1998 10:10:09 -1000 (HST) Hi all. Recording large P and S waves in Hawaii at ~19:55 UTC _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Conti Claudio" Subject: R: Large Event Comming In Date: Sun, 29 Mar 1998 22:35:04 +0200 TELESISMIC REGISTRATION. I RECORDED MEDIUM P ED LARGE S IN SIRACUSA OBSERVATORY.(SICILY) ARR.TIME 20,01 UTC. REGARD CONTI CLAUDIO _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Canie Brooks Subject: Re: Large Event Comming In Date: Sun, 29 Mar 1998 12:28:30 -0800 At 10:10 AM 3/29/98 -1000, Donna Whitaker wrote: >Hi all. > >Recording large P and S waves in Hawaii at ~19:55 UTC Hows this: D a t e Time (UTC) Location Dep Magni. T AGY R e g i o n HHMM 29Mar1998`20:06' A SED PKP AZ= 33 SL=1.683 2012 29Mar1998 19:48:13.0 11.0S 178.0W 33 mb=5.4 A*YKA N. OF FIJI ISLANDS 2018 29Mar1998 19:47:23.0 17.4S 179.2W 33 mb=7.1 A*NEI FIJI ISLANDS REGION 2007 29Mar1998 19:47:07.0 20.0S 178.0W 33 mb=6.7 A*YKA FIJI ISLANDS REGION 2018 Radius: 502 km > > > > >_____________________________________________________________________ > >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: Large Event Comming In Date: Sun, 29 Mar 1998 12:51:13 -0800 Canie I picked it up here also. How did you get the event info so fast? Barry Canie Brooks wrote: > Hows this: > D a t e Time (UTC) Location Dep Magni. T AGY R e g i o n > HHMM > > 29Mar1998`20:06' A SED PKP AZ= 33 SL=1.683 > 2012 > 29Mar1998 19:48:13.0 11.0S 178.0W 33 mb=5.4 A*YKA N. OF FIJI ISLANDS > 2018 > 29Mar1998 19:47:23.0 17.4S 179.2W 33 mb=7.1 A*NEI FIJI ISLANDS REGION > 2007 > 29Mar1998 19:47:07.0 20.0S 178.0W 33 mb=6.7 A*YKA FIJI ISLANDS REGION > 2018 > Radius: 502 km > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Liberio Rossi" Subject: Recorded teleseismic event Date: Sun, 29 Mar 1998 21:53:41 +0200 Recorded event h.20,07,20 Lat.43°54' 79 N Long. 10°31' 56E Possible M = 5.3 liberio .rossi@........ LIBERIO ROSSI From: Canie Brooks Subject: Re: Large Event Comming In Date: Sun, 29 Mar 1998 12:51:50 -0800 At 12:51 PM 3/29/98 -0800, barry lotz wrote: >Canie > I picked it up here also. How did you get the event info so fast? I used this URL which seems to have info the quickest...: http://seismo.ethz.ch/redpuma/redpuma_ami_list.html > Barry > >Canie Brooks wrote: >> Hows this: >> D a t e Time (UTC) Location Dep Magni. T AGY R e g i o n >> HHMM >> >> 29Mar1998`20:06' A SED PKP AZ= 33 SL=1.683 >> 2012 >> 29Mar1998 19:48:13.0 11.0S 178.0W 33 mb=5.4 A*YKA N. OF FIJI ISLANDS >> 2018 >> 29Mar1998 19:47:23.0 17.4S 179.2W 33 mb=7.1 A*NEI FIJI ISLANDS REGION >> 2007 >> 29Mar1998 19:47:07.0 20.0S 178.0W 33 mb=6.7 A*YKA FIJI ISLANDS REGION >> 2018 >> Radius: 502 km >> > >_____________________________________________________________________ > >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: "Conti Claudio" Subject: R: Large Event Comming In Date: Sun, 29 Mar 1998 22:59:10 +0200 >>>CORRECTION <<< PHASE P ARR.TIME 20 07 25 UTC. REGARDS CONTI CLAUDIO _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Large Event Comming In Date: Sun, 29 Mar 1998 15:28:44 -0800 (PST) Just arrived in my email! Magnitude 6.4 earthquake near FIJI ISLANDS REGION 17.42S, 179.24W depth 539.0km Sun Mar 29 19:48:16 1998 GMT An earthquake has occurred. Following is information provided by the National Earthquake Information Service of the USGS. This information is preliminary and subject to correction. Time: GMT Sun Mar 29 19:48:16 1998 (EST Sun Mar 29 14:48:16 1998) (PST Sun Mar 29 11:48:16 1998) Magnitude: 6.4, determined using its body wave characteristics Epicenter: 17.42S, 179.24W (FIJI ISLANDS REGION) Precision: A, where A is fine and D is coarse. Depth of focus: 539.0km below sea level at the epicenter. For a map showing this event, please consult the web page Further info can be obtained from the USGS National Earthquake Information Center at or the USGS home page at >Hi all. > >Recording large P and S waves in Hawaii at ~19:55 UTC > > > > >_____________________________________________________________________ > >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: Karl Cunningham Subject: Re: Books to get me started Date: Sun, 29 Mar 1998 15:40:31 -0800 Chuck -- You might try Barns & Noble's web site (I don't have the URL). I ordered Bolt's book through them about a year ago without any problem. Sorry, I don't want to part with it. -- Karl Cunningham karlc@....... At 07:55 PM 3/28/98 -0800, you wrote: >I am a newcomer to this list and a worse than rank amateur at >seismology. I wanted to get some good introductory texts and ordered >Earthquakes and Geological Discovery (Scientific American Library, Vol >46) Bruce A. Bolt / Published 1993 from Amazon. They now tell me that >the book is not available. Does anyone have a copy they would be >interested in selling me? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "David A. Nelson" Subject: Re: Antartic ice shelf Date: Mon, 30 Mar 1998 12:10:48 +1200 At 02:59 AM 3/29/98 -0800, you wrote: >Hi Arie: >I downloaded and viewed the geoid picture. I see that the area near the >epicenter is below average by 40 meters. I couldn't tell if it was under an >ice-cap or not. But, according to the theory it certainly looks promising. >Do you think that the weight of the ice above the epicenter might have >caused the earthquake? > >Frank Condon >frankcnd@.......... Unfortunately there is little of no ice above the epic, Frank, except surface sea ice in winter so ice is NOT the cause Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://psn.quake.net/dave/home.htm IF there indeed are other parallel universes... I can now rest in the knowledge, that in at least one of them, I am filthy rich and drive a red Ferrari _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: frankcnd@.......... (Frank Condon) Subject: Re: Antartic ice shelf Date: Sun, 29 Mar 1998 17:08:47 -0800 (PST) >Unfortunately there is little of no ice above the epic, Frank, except >surface sea ice in winter > so ice is NOT the cause > > >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 > > >_____________________________________________________________________ > Hi Dave: Thanks for clearing up things for me. It's sometimes can be hard to see what is going on away over there! Your knowledge of the region; "I don't know what we would do without it." What do you think that this 40 meter depression in the geoid at the epicenter is indicative of? Best regards, Frank Condon frankcnd@.......... "Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Jayme Wing Subject: Re: radio frequencies? Date: Sun, 29 Mar 1998 18:02:54 -0800 bschafer@......... wrote: > > Hi, I am new to the list and I do have a question. Is there a radio > frequency that I can tune to to hear seismic activity? I am blind so a > seismograph wouldn't be of much use to me. There used to be a radio > frequency--162.810--that used to emit a steady sound when there were no > quakes in progress. When there was a tremor the tone would become more > high pitched--the hier the larger the quake. > > Thanks for any information on this. > > 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 Bonnie, Here are three frequencies that I monitor. These are active in the Los Angeles area. 164.847, 408.500 and 408.979. The 408 frequencies are also active in Mammoth Lakes area. These are very low power, horizontally polarized signals. The signal strength will increase if you turn your antenna level with the Horizon. Also, let me know where you are located. Jayme Wing KB6JGR _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: RADIOTEL Subject: Re: Boom diameter, ETC. Date: Sun, 29 Mar 1998 22:13:34 EST What would be the performance difference between using a 1/2 diameter boom rather than a 3/8 inch boom on a lehman seismograph? The boom will be about 30 inches long. I have also seen pictures of lehmans with the suspension wire made out of wire and a threaded rod. What is the purpose of the threaded rod? Also, does anyone know where one can find cow magnets in the Los Angeles California area? Jim Allen Cerritos, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: shammon1@............. Subject: Re: Books to get me started Date: Sun, 29 Mar 1998 22:14:43 -0800 I see you are in Saratoga. The used book store in Mt.View has a geology section and a week ago it had a copy of Bolt's Earthquake which has a lot of the same text. You can also try the used book store in downtown Santa Cruz a block or two west of the movie show. It had a few of Bolts books in its stacks about 6 months ago. Regards, Steve Hammond PSN San Jose Chuck Erickson wrote: > > I am a newcomer to this list and a worse than rank amateur at > seismology. I wanted to get some good introductory texts and ordered > Earthquakes and Geological Discovery (Scientific American Library, Vol > 46) Bruce A. Bolt / Published 1993 from Amazon. They now tell me that > the book is not available. Does anyone have a copy they would be > interested in selling me? > > Also, I found the following texts that might be OK for a new student. > If anyone has read either one and would like to give me some feedback I > will be very grateful. > > Seismology - H. A. Doyle, et al / Published 1996 > > Modern Global Seismology (International Geophysics Series, Vol 58) > Thorne Lay, Terry C. Wallace / Published 1995 > > Thanks for your help, > > Chuck Erickson - Saratoga, CA > mailto:cee@............. > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Al Allworth" Subject: Re: Boom diameter, ETC. Date: Sun, 29 Mar 1998 23:31:06 -0800 -----Original Message----- From: RADIOTEL To: psn-l@............. Date: Sunday, March 29, 1998 7:34 PM Subject: Re: Boom diameter, ETC. >Also, does anyone know where one can find cow magnets in the Los Angeles >California area? >Jim Allen You might try some of the farm stores in the Chino area. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: shammon1@............. Subject: Re: Boom diameter, ETC. Date: Sun, 29 Mar 1998 23:38:15 -0800 That was Jerry Darbey's (PSN Pasadena) Lehman. The drawing are in the Lehman zip I put together back when we just had BBS's. I think Larry now has them on his web site. JD told me that he used the steel rod and treaded everything because he was not sure how he wanted to position it. He could just move it around as needed. Good idea-- 3/8 steel may not be too thin, however it is steel and if you use magnets for damping you will need to extend the rod end with a wood extension to mount the damping flag on. This would mean drilling and taping a wood dodowel as in the orginianl 1950's Scientific America Lehman design. Another idea is to try 3/8-in brass but it also has a problem. I built my a toilet-tank seismograph (the mass was a toilet float filled with water) out of 3/8-inch brass rod. The boom had a real bad tendency to flex in larger local earthquakes. I ended up having to bridge the boom with support wires under tension. Not a good design. The mentioned boom now hangs on the wall to my right... I've had the best luck with 1/2-in sq. aluminum rod. It's also easy to work with becouse the edges are flat. It's easy to mount "stuff" on if you like to try different ideas. As an exaple. I have two Lehmans. I pulled the E/W lehman out of the seismic house a month ago because the wires were rusted and about to break. However, I just found the time to play with it, today. After bolting the unit to a workbench, because of the flat edge, I was able to glue a mirror to the side of the square boom and us a laser-beam to measure the travel of the boom in relation to the horozontal displacement of the upright support. This worked so well, I still have it in the shop and want to make a few more measurements. Now you must be asking yourself, does this mean that if you use sq. aluminum you will never actully mount it on the ground? I don't know-- it's up to you. But, it was sure nice to have a flat edge to work with. Those are my thoughts. If you would like to see the seismograph I'm talking about, take a look at the PSN San Jose Web site. Regards, Steve Hammond RADIOTEL wrote: > > What would be the performance difference between using a 1/2 diameter boom > rather than a 3/8 inch boom on a lehman seismograph? The boom will be about > 30 inches long. I have also seen pictures of lehmans with the suspension wire > made out of wire and a threaded rod. What is the purpose of the threaded rod? > > Also, does anyone know where one can find cow magnets in the Los Angeles > California area? > Jim Allen > Cerritos, California > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "Erich F. Kern" Subject: Re: Boom diameter, ETC. Date: Sun, 29 Mar 1998 23:56:14 -0800 > From: RADIOTEL > To: psn-l@............. > Subject: Re: Boom diameter, ETC. > Date: Sunday, March 29, 1998 19:13 > Also, does anyone know where one can find cow magnets in the Los Angeles > California area? > Jim Allen > Cerritos, California There are some in the Edmund Scientific Co. catalog. __ ____________________________________________________ > > 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: Karl Cunningham Subject: New format available for ISAIAH list Date: Mon, 30 Mar 1998 08:56:22 -0800 Greetings -- For those interested in So. California events and who use the "Information on Seismic Activity In A Hurry" (ISAIAH) list from SCSN, there is a new format (text) available at http://www-socal.wr.usgs.gov/given/review/hyp.list If the first 11 characters are removed from each line, Winquake will recognize it as a valid report file format. I wrote a macro in my text editor to do this. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: watson@................ (Charles Watson) Subject: Re: New format available for ISAIAH list Date: Mon, 30 Mar 1998 10:02:07 -0700 Karl Cunningham wrote: > > Greetings -- > > For those interested in So. California events and who use the "Information > on Seismic Activity In A Hurry" (ISAIAH) list from SCSN, there is a new > format (text) available at > > http://www-socal.wr.usgs.gov/given/review/hyp.list > Karl, tried the URL and got the error message: "Document contains No data" humm... -- ---/---- Charles P. Watson Seismo-Watch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: "James M Hannon" Subject: Re: New format available for ISAIAH list Date: Mon, 30 Mar 1998 13:08:35 -0500 Tried the link here and it seems to work. Here is a sample: 9048434 CI 98/03/27 18:55:53 33.68N 116.76W 13.8 1.1MH B 5 mi. SSW of IDYLLWILD 9048435 CI 98/03/27 19:11:34 36.08N 117.63W 7.1 1.3MC C 20 mi. SSW of PANAMINT SPRING 9048443 CI 98/03/27 20:03:25 33.07N 114.94W 0.0 2.2MC A 31 mi. NW of YUMA 9048458 CI 98/03/27 20:21:56 34.26N 116.45W 0.0 1.5MC C 10 mi. N of YUCCA VALLEY 9048460 CI 98/03/27 20:23:52 35.94N 117.39W 2.4 2.4MC A 13 mi. N of TRONA 9048471 CI 98/03/27 21:46:02 34.64N 116.50W 3.6 1.2MC C 29 mi. ENE of LUCERNE VALLEY 9048474 CI 98/03/27 22:03:04 36.08N 117.63W 9.2 1.1MC C 20 mi. SSW of PANAMINT SPRING 9048475 CI 98/03/27 22:33:23 33.66N 117.05W 0.0 1.7MC A 8 mi. SW of HEMET 9048476 CI 98/03/27 22:41:37 36.08N 117.62W 8.6 1.2MC C 20 mi. SSW of PANAMINT SPRING Jim Hannon watson@................ on 03/30/98 11:02:07 AM Please respond to psn-l@............. To: psn-l@............. cc: (bcc: James M Hannon/CedarRapids/Collins/Rockwell) Subject: Re: New format available for ISAIAH list Karl Cunningham wrote: > > Greetings -- > > For those interested in So. California events and who use the "Information > on Seismic Activity In A Hurry" (ISAIAH) list from SCSN, there is a new > format (text) available at > > http://www-socal.wr.usgs.gov/given/review/hyp.list > Karl, tried the URL and got the error message: "Document contains No data" humm... -- ---/---- Charles P. Watson Seismo-Watch _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: New format available for ISAIAH list Date: Mon, 30 Mar 1998 14:25:11 -0800 At 08:56 AM 3/30/98 -0800, Karl wrote: >Greetings -- > >For those interested in So. California events and who use the "Information >on Seismic Activity In A Hurry" (ISAIAH) list from SCSN, there is a new >format (text) available at > >http://www-socal.wr.usgs.gov/given/review/hyp.list > >If the first 11 characters are removed from each line, Winquake will >recognize it as a valid report file format. I wrote a macro in my text >editor to do this. > The next release of WinQuake will be able to load this report directly. I will have a beta release ready in a few days. If anyone knows of a report / event list like this ,that WinQuake does not support yet, please let me know. The list must have all of the information about the event on one line. A more complex page gets to hard to parse... I modified WinQuake so that it will load html pages directly (the previous release only allowed for ftp transfer) so the event list can be a web page. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: lahr@.................. Subject: seismology software site Date: Mon, 30 Mar 1998 15:42:21 -0700 (MST) This site, Observatories and Research Facilities for EUropean Seismology, ORFEUS, has information and links that may be of interest, including software, such as the IASPEI* shareware library programs. http://orfeus.knmi.nl/ *IASPEI = International Association of Seismology and Physics of the Earth's Interior 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://www.aeic.alaska.edu/lahr http://www.lahr.org/john-jan _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: S-T Morrissey Subject: boom centering motor Date: Mon, 30 Mar 1998 18:53:28 -0600 (CST) Meredith, The boom centering motor has to turn a fine thread (eg 8-32) screw with an eccentric (so it won't turn) weight of 10 to 50 grams hanging on it oriented along the axis of the boom. The Edmund Scientific catalog has some nice miniature geared-down DC reversible motors that weigh an ounce or two and draw less than 100 ma. In particular, look at the motor part number J41331, a 2RPM, 31 inch-ounce laboratory- grade (=$25) motor that runs on 8 milliamps at 12 V unloaded and is 1.75" dia x 1.75" long. THe motor can be mounted over the centerline of the hinges so as to minimally affect the boom and the feedback coil/magnet. THere is no problem with powering it via a pair of the fine coiled wires that convey the signals over the hinges (I have two extra pair installed). The fine #38 wire that I use can handle 2.5 amperes before it melts, so a few hundred ma won't be a problem. The above motor can be controlled manually with a DPDT switch, and will run quite nicely on a 9-volt battery; one could also set up an auto-zeroing system using the integrator (= mass position) output of the VBB feedback to control it via a meter relay (hard to find a center-scale meter relay) or electronic comparators and cmos switches. I am also experimenting with electronic centering to extend the operating temperature range. To do this, I integrate the mass position output again with an extremely long (gt. 1000 seconds) time constant and apply it through a limiting resistor to the auxillary 25-turn coil above the main feedback coil. I am using a passive filter (ie very large capacitors) to avoid adding noise. I have yet to evaluate the change in the overall response. regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Larry Cochrane Subject: Re: IRIS software seminar at Santa Cruz Date: Mon, 30 Mar 1998 17:31:53 -0800 FYI... -Larry >Date: Mon, 30 Mar 1998 09:52:56 -0700 (MST) >From: Michelle Hall-Wallace >To: Larry Cochrane >cc: Michelle Wallace >Subject: Re: IRIS software seminar at Santa Cruz > >Dear Larry, > >Below is the letter I am sending to some other people to invite them to >the IRIS workshop. It contains information you need as well. Please >confirm you can participate and supply the needed information. >Thanks, > >Michelle > >-------- >IRIS is sponsoring a one day workshop on educational software at the July, >18 Annual Meeting in Santa Cruz, California. The purpose of the workshop >is to bring seismologists together with software developers to learn more >about the software available for teaching seismology in grades K-16. Our >goals are to promote the use of technology in teaching seismology and to >help identify needs and directions for future software development. > >I would like to invite you to present WinQuakes at the July 8 workshop in >Santa Cruz. The workshop will consist of presentations and hands on >instruction in which participants learn to use the software. This will be >followed by discussions and examples of how the software can be used in >teaching. The workshop will wrap up with a discussion of unmet needs and >directions for software development. It is our desire to provide >developers with ideas and community support for their development efforts >so that they may solicit funds from NSF or other agencies to continue >their work. > >We have reserved a computer facility with 20 Power Macintosh 7600s and 20 >PC clones. Each participant will be able to work with the software at >their own computer during your presentation. Presenters will have access >to a computer driven projection unit as well. Your presentation should >address the features of your software and contain examples of how the >software can be used in an educational setting. We plan to give each >participant and presenter a notebook that contains 1) information about >each software application presented and 2) ideas/activities for using the >software in the classroom. If there is a user manual and installation >instructions, we can provide them as well. If you have any example >activities, I would appreciate receiving a copy by June 1 to duplicate >them for the notebook. > >I hope you will be able to join us at the workshop. > >Michelle Hall-Wallace > > >Michelle Hall-Wallace Phone: (520) 621-9993 >Building 77 >Dept. of Geosciences Fax: (520) 621-2672 >University of Arizona >Tucson, AZ 85721 > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) From: Roger Griggs Subject: Re: cee@............. Date: Mon, 30 Mar 1998 21:32:56 -0800 > >"Elementary Seismology" >by Charles F. Richter; > >It's hard to find! I've been trying to get a hold of a copy from Amazon >Books for about a couple of months. Also, I've heard that it can be >expensive if you can even find a good used copy. It was mentioned once that >someone paid $150.00 for it. A good book can be tough to find, even at that >kind of a price. Now, I didn't think of looking at the library for it. Well, >good luck and just maybe someone out there will know of a good source for >cheap used seismological books. > >Frank Condon >frankcnd@.......... >"Located in the seismic corridor somewhere between Fontana & Mammoth Lakes" Hi Frank, You are right, Richter's book is an excellent start for a beginner and is fairly easy to follow. Even though it is somewhat dated, 1958 by W.H. Freeman and Co. Inc. San Francisco, it has a wealth of information. I checked out a copy from the USGS library a couple of years ago, read it cover to cover. I really couln't set it down. I was very lucky to locate and purchase a first edition copy of Elementry Seismology in excellent condition for $52. In fact the book store had two copies. That was about a year ago. The name of the store is Books from Bree. They specialize in out of print technology and science books. You can email shoshana@............. and request a search at no cost. Their phone is 818-766-5156. Good Luck Roger _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L)