From: S-T Morrissey Subject: thermal convection in LP sensors Date: Thu, 31 Dec 1998 14:58:45 -0600 (CST) Regarding thermal convection in LP instruments: This has long been a problem with high gain observatory instruments, even in large secure vaults. The earths' heat flow out of the ground is always present, even when a large pier is in the way. If the environment above the pier is cooler, problems result. In a cavern or mine, the temperature difference is minimal if the area is closed off, but it can still be present. Within an instrument enclosure, the base will warm up a boundary layer of air, which will eventually peel away and invert with the cool air in the top of the case, usually at periods of 10 to 100 seconds. Insulation inside, on top of the baseplate, as well as baffles within the case, will help, but more often just make the problem more interesting. The most common system with the problem came with the WWNSSS (Worldwide network of standard seismograph stations) in the 1950s, where a set of 30-second long period sensors was connected to 90-second galvanometers. The steel cases of the LP sensors were equipped with small 10-watt cartridge heaters in the very top of the case, and a small variac transformer was used to adjust the heat so that the convective noise just disappeared from the (photographic) record. Too much heat would set up its own noise. Thermostatic arrangements only added another cycle to the problem, not only to the thermal convection but to radiant heating of the sensor. To minimize the heat required, as much fiberglass insulation as possible was installed under the seismometer baseplate, which was usually about 2cm above the pier. In a small underground vault in the Ozarks, the LPs are on 10cm high piers on the rock floor, but the vault is a heavy aluminum streem culvert and a big heat sink, so more heat was needed. I use 220-volt, 50 watt band-style air-conditioner case heaters running on 110v for 25 watts and an indefinite life, and resting on the outside of the steel case, where the mice loved them. For lower wattage and indefinite life, regular 10 watt bulbs can be used in series; we want the heat, not the light, and a burned out bulb can make a very mysterious transient in the data. Strip heaters can be found in surplus stores, and when used in series they don't burn out or burn your hand. Regarding insulation: fiberglass matting gives much greater protection than lighweight styrofoam panels because it has significant thermal mass along with its insulation properties. As Meredith notes, large R-values can be realized with a lightweight plywood box with 4" of fiberglass (or other heavy closed-cell panels) on each side. The more mass in the thermal barrier, the longer the time constant is. To remove the daily thermal noise in 3m deep tiltmeter pits in the Aleutians, we bagged up the volcanic soil and packed it around the sensors, and it reduced the diurnal thermal noise by a factor of 100. So if you can sand-bag your vault ..... or go deeper underground ...! 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 From: "David A. Nelson" Subject: new year Date: Fri, 1 Jan 1999 10:00:12 +1300 Happy new year to all from new zealand i trust that 1999 will bring new challenges and great advances for the PSN and for all in their family lives 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 From: macsmith Subject: Re: thermal convection in LP sensors Date: Thu, 31 Dec 1998 11:28:39 -1000 For the professionals with budgets, I would have thought that enclosing instruments in a vacuum would eliminate all of theses problems. Has anyone use such things? Happy New Year Ian Smith _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: JIm Hannon Subject: Re: thermal convection in LP sensors Date: Thu, 31 Dec 1998 18:25:07 -0600 macsmith wrote: > For the professionals with budgets, I would have thought that enclosing > instruments in a vacuum would eliminate all of theses problems. > > Has anyone use such things? > > Happy New Year > > Ian Smith > I am busy working on a vacuum enclosed seismograph. There is not too much expense except for the pump to pull the vacuum. But eventhough a vacuum eliminates a lot of problems with convection currents and barometric pressure changes. I suspect that it will have its own set of problems starting with leaks and case flexture. We shall see. Happy New Year -- 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 From: KACAMACHO@....... Subject: Re: new year Date: Thu, 31 Dec 1998 20:09:47 EST HAPPY NEW YEAR TO YOU TOO! _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Fred Subject: Re: thermal convection in LP sensors Date: Thu, 31 Dec 1998 17:11:41 -0800 That would be an ideal housing but a fairly expensive undertaking. That would have to be a pretty strong box. If anyone in the bay area wants to try this, I own a pretty good pump that I could loan out. I wonder if the amp's would have to be outside if the tank as the thermal dissapation will be much different. Happy New Year all Fred -- How much choice did God have in constructing the Universe? If the no boundary proposal is correct, he had no freedom at all to choose initial conditions. He would have only had the freedom to choose the laws the universe obeyed. Albert Einstein _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: macsmith Subject: Re: thermal convection in LP sensors Date: Thu, 31 Dec 1998 16:51:05 -1000 I should urge a little caution about using a vacuum. Firstly, one wouldn't use a "box", but a "vacuum vessel", these are usually aluminium, whose walls are 0.25 to 0.5 of an inch thick. Otherwise there is a risk of implosion. Secondly, some vacuum pumps have an exhaust port which has to be vented to the outside, the fumes (evapourated vacuum oil) are poisonous (I can't remember how to spell carsogenic!). One might also think of adding a vacuum guage, to see how good the vacuum is - more expense. All our instruments at the telescopes use these, and we have (working) amps inside, not just at vacuum, but close to Liquid Nitrogen temperature - now there's a thought, low noise amps. Happy New Year. Ian Smith _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Robert Avakian Subject: Re: thermal convection in LP sensors Date: Thu, 31 Dec 1998 21:38:24 -0800 Question. As long as thremal events had periods several times the period of the longest waves, I would think they could be filtered out quite effectively after the fact. So all one would need would be a box which slowed or damped the enviornmental changes effectively. Might a water jacket with a circulating pump be a cheaper and easier alternative to the vacuum scheme? I assume the circulating water could cause a problem, but the pump would not need to run continuously, perhaps several seconds every few minutes? Bob A. macsmith wrote: > > I should urge a little caution about using a vacuum. > > Firstly, one wouldn't use a "box", but a "vacuum vessel", these are usually > aluminium, whose walls are 0.25 to 0.5 of an inch thick. Otherwise there is > a risk of implosion. > > Secondly, some vacuum pumps have an exhaust port which has to be vented to > the outside, the fumes (evapourated vacuum oil) are poisonous (I can't > remember how to spell carsogenic!). > > One might also think of adding a vacuum guage, to see how good the vacuum is > - more expense. > > All our instruments at the telescopes use these, and we have (working) amps > inside, not just at vacuum, but close to Liquid Nitrogen temperature - now > there's a thought, low noise amps. > > Happy New Year. > > Ian Smith > > _____________________________________________________________________ > > 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 From: S-T Morrissey Subject: evacuated containments Date: Fri, 1 Jan 1999 01:34:00 -0600 (CST) Re vacuum contaiment for seismometers: They have been used since the 50's for high gain long-period sensors, but because these sensors were large (50 cm or more), they were large and dangerous (30" steel tanks), and had serious problems with flexure of the interface between the seis and the pier. But a pressure contaiment for the vertical is necessary to reduce the barometric buoyancy noise by a factor greater than 100. So the current long-period configurations of the major commercial VBB sensors are much smaller, with dimensions within 10 cm, and have isolated bases of Stainless steel or aluminum that are 1 to 2 cm thick, and the covers are coupled to the base with large, often double, O-rings so that flexing of the covers is not transmitted to the base. For barometric noise control, the cover does not have to be evacuated, just vacuum tight. THis however, does not provide thermal control. 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.) The major exception is the STS-1, the cadillac of VBB seismometers, which operates at 360 seconds with a noise level below the low noise earth model. This sensor 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. All three components are evacuated, so both barometric and thermal (as well as humidity) control are provided. The vacuum needs to be good, but not "high", like better than 29" of Hg. Recently, the Albuquerque lab has been making a "warpless" baseplate for field re-installation of the STS-1 without the grouted pyrex plates. Photos of such can be found at: http://www.eas.slu.edu/People/STMorrissey/ stmmisc.html PSN INFO ... SLU Seismic Network and a photo of the STS-1s installed on a pier at CCM can be found through: stmiris.html St. Louis Univ. IRIS Broadband Stations I recently re-installed a set of STS-1 at a station near Nashville using the warpless baseplates; I will post the photos when I get them. OTher notes: (repeating some observations by others) 1. Evacuating any 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. The container should hold the vacuum indefinitely, since the pump makes vibrations, and a dial vacuum gauge is needed. For the short run of the pump, the vapors are not a problem, no more than automotive oil. While I was working on the cyclotron, we had pumps coating oil vapor on everything, which maybe helped our electrical arcing problems; however, I'm sure that any chance of oil vapor deposition around a telescope is a no-no. 2: Enclosing the seismometer means that the container base 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, just like putting a gallon jug of water on it. It should not measurably deflect within the tilt sensitivity of the sensor, usually less than a micron. 3. 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. 4. 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. Also, a practical note: If one uses a steel container, like the domed end of a steel tank that I use for vacuum grouting, 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. 5. 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) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: RLLaney@....... Subject: Lehmans and cold weather/thermal convection Date: Fri, 1 Jan 1999 14:52:31 EST Meredith, Greg and Sean-Thomas: I appreciated the notes on your experiences and the suggestions concerning thermal interference. I would love to have a vault and have even considered devoting some garden space to one. But, I have a hunch that I would generate a whole new set of problems for myself. So, I think I will keep the sensors on the garage floor, but will try additional insulation and baffles. Thanks. Bob _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Arie Verveer Subject: Station near you. AutoDRM Date: Sat, 02 Jan 1999 18:56:28 +0800 Hi All, I've just finished writing a "DOS" program that converts the "AutoDRM" waveform files to a file compatible with Winquake. This means you [YOU] have access to over 1,200 professional seismograph channels, World wide. You can request Waveform data from these instruments. If you need to check out that small local event, you now can, via email. Or if you are interested in an event on the other side of the plant and would like to see the original data, you can. See http://www.iinet.net.au/~ajbv/ The test data from Alaska should be "FFT" filtered with a 1.5Hz high pass filter, (Winquake) before you can see the event. I did this to demonstrate that the data from professional seismographs suffer from all the noise problems the PSN community does. Anyhow, this is essentially my first "C" program, so if you find a major bug, please let me know. I hope to eventually locate my local events All the best Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Re: Update on Dominica Date: Sat, 02 Jan 1999 12:47:54 -0700 John- Happy Holidays & New Year! We're ... back in the USSA ... Do you have the reference for Dave Hill's paper? -Edward John Lahr wrote: > Hi Wayne, > > One possible source of the noise is the P-phase itself. I was > in the Imperial Valley of California during a swarm of earthquakes > that were shallow and not far away. I could hear them before > I felt them. Some microphones were added to one channel of the > seismic recorders and it was determined that we were hearing the > P-phase and then feeling the S-phase. Dave Hill wrote a paper on > this and showed that the earth was acting like a drum head and > amplifying the vertical motion of the P-phase. > > The earthquakes sounded like thunder in the distance. > > If people are hearing events now, but they did not hear them > in the past, this could be due to a change in earthquake location, > magnitude, or focal mechanism. > > JCLahr > ################################## John C. Lahr > ################################# Seismologist > ################################ U.S. Geological Survey > ############################### Geologic Hazards Team, MS966 > ############################## PO Box 25046 > #############################/############################## > ############################/############################### > Denver, Colorado 80225-0046 ################################ > Phone: (303) 273-8596 ################################## > Fax: (303) 273-8600 ################################### > lahr@........ ##################################### > http://giseis.alaska.edu/lahr > http://lahr.org/john-jan > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- 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 From: John Hernlund Subject: Re: Station near you. AutoDRM Date: Sat, 02 Jan 1999 18:12:03 -0700 (MST) On Sat, 2 Jan 1999, Arie Verveer wrote: > Hi All, I've just finished writing a "DOS" program that converts the "AutoDRM" > waveform files to a file compatible with Winquake. Arie, What is the difference between AutoDRM files and SAC files? I usually use the latter, so I haven't come across this file type. Who is using 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) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Arie Verveer Subject: Re: Station near you. AutoDRM Date: Sun, 03 Jan 1999 10:48:48 +0800 Hi John John Hernlund wrote: > > What is the difference between AutoDRM files and SAC files? I usually use > the latter, so I haven't come across this file type. Who is using it? > It appears that "AutoDRM" outputs are given in plain text while SAC outputs are in binary(?). I assume that the plain text is given, so as to cover all possible types of data transfer. There is a good smattering of countries around the world that use AutoDRM and each of these have many professional stations connected to them. Most likely they give there outputs in SAC and AutoDRM and whatever form, the profession geophysical community needs. The good thing for a PSN user is that we can get very, nearly real time waveform data from all over the world. In Western Australia this sort of data access is marvellous, I can now confirm any possible local events. Normally I had to wait until the middle of the next month before the states Geophysical Centre would publish there findings. But since that centre is going to close down in about a year, that will be it, no more data. The seismic stations are going to be controlled from the eastern side of the country. The AutoDRM site. All the best Arie See http://www.iinet.net.au/~ajbv/ if you are interested. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Arie Verveer Subject: Update: Station near you. AutoDRM Date: Sun, 03 Jan 1999 13:32:25 +0800 Hi All, Sorry about this, but it turns out that if you have multiple requests in a AutoDrm request and the station name stays the same then the program "GSEtoPSN.exe" will overnight file name with next decoded data block. I've now fixed this, by making the extension the same as the channel name. I've latest software is at. http://www.iinet.net.au/~ajbv/ Oh well.......... Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Mark Robinson" Subject: New Zealand event and links to IGNS Date: Sun, 3 Jan 1999 21:20:50 +1300 Hi folks A couple of related events near Wellington today. 4.2 and 5.1. see http://www.gns.cri.nz/news/earthquakes/latest_drum.html http://www.gns.cri.nz/news/earthquakes/recent_quakes.html regards Mark G Robinson | ZL2TOD | other@............... Box 8770, Auckland 1035, New Zealand Phone +64-9-846-3296 | Fax +64-9-849-7408 ------------------------------------------------ 03 Jan 1867 Te Whiti released from prison in the South island. 03 Jan 1959 Alaska becomes the 49th state of the U.S.A. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: Capacitors Date: Sun, 03 Jan 1999 09:51:24 -0800 Brett & Fred Thanks for your capacitor input. I haven't checked your links yet Brett. I have been using Don Lancaster's Active filter cookbook to design my instrument filtering. I just went from a 4 pole Butterworth lowpass(10 hz) to a 6 pole. I now seem to be getting more periods of 10 hz oscillations. I guess they are triggered by transient input or/and low damping? They are configured similar to Larry's board but with different values. Currently all the caps are equal (0.15u) . To all: Would decreasing the feedback cap slightly reduce the oscillations? Regards Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: macsmith Subject: Pacific Rim Quakes Date: Sun, 03 Jan 1999 08:12:02 -1000 here's an interesting news report on the recent Pacific rim quakes: http://www.news.bbc.co.uk/hi/english/world/asia-pacific/newsid_247000/247363.stm _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: VBB and filters Date: Sun, 3 Jan 1999 14:04:57 -0600 (CST) Barry, I am uncertain where you are using the filter, why, or why you seem to have an undamped response. As I recall, you are using the latest triple feedback VBB configuration, as used for the STS-1, the Guralps, and the STM-8. I justed looked at the transfer function I have here for your 6" design, based on some of the parameters you sent some time ago. It has an r = 234 000 V/m/sec. G=12.65 N/A; M=0.35kg; Cp=24uf; Rp=1 meg ohm; RI=0.107 meg ohm, and Ti= 80 seconds. and To = 1.7 seconds. ... and looks like it should be quite stable, with Tn = 90 seconds. (most of the numbers are defaults from the STM-8; you can update them). It is important to know the sensitivity of your displacement transducer to properly use the Mathcad model of the transfer function. The resulting response quite accurately reflects what you get, as I have previously shown in the calibration data. The transfer function will indicate an oscillator if either end of the flat velocity response has an inflection in it. If the damping term zeta is much less than 0.6, the oscillation will be at the effective period, like 20 to 100 seconds, depending on your configuration. If the response has a bump at the short period end, several instabilities are possible due to "out of range" selection of the feedback components, like the value of Cp is too large or r is too small or too large. The response should be quite flat. The usual cause of oscillation or ringing is because r is too large. As Brett's effort shows, there is little in the loop to damp the high-end oscillation if the loop has the gain to oscillate there. To determine the actual value of r, the gain(s) of the displacement amplifier(s) need to be known; this is readily determined from the elements in their feedback per your schematic. Like for one of the VBBs here, the transducer is 58mv/micron, the first amp is x3, the second is x10, so the value used in the Mathcad function (which uses MKS units) is 1 740 000 volts/meter. (1.74 million V/m sounds hugh, but it is a reality of the VBB). My old transfer function response indicates an oscillation at 300-400hz, which I can hear, but I killed it with appropriate low-pass filtering (a larger feedback capacitor) in the 2nd X10 displacement amp. To control (= live with) local cultural noise (= the street) I use 2-pole filters at 2 hz (or so) in the line driver amplifier, which is a high-pass (1000 second) output of the VBB signal. These are outside the loop, so only affect the "cosmetic" appearance of the data, reducing the local noise so I can see microseisms and teleseisms. So determining their parameters is mostly a trial and error activity. Lancaster's book is a good resource; it shows different damping options for the filters on pages 75-77; you might want to use what he calls the "compromise" between best delay and flattest response, which is (referring to the NASA Active filter Design Handbook (SP-5104; 1977), a "Legendre" response, somewhat between a Bessel and a Butterworth response. Anything with ripple in the passband (the Chebyshev filter) will have a sharper cutoff, but will ring in response to an impulse. 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 From: barry lotz Subject: Re: VBB and filters Date: Sun, 03 Jan 1999 13:24:23 -0800 Hi Sean Thomas Thanks for your response. I'll spend some time reviewing the content. I'm not having a problem with the VBB, it's with the Lehman when it comes into the house. The sensor is in the garage (~50 ' away) and when it comes in on a shielded cable I filter it with a 6 pole low pass. The circuit inside was a 30k load resistor followed by a noninverting 10X preamp, 6 pole butterworth, 1 pole 0.008 hz highpass, 18X amp, and 10 hz single pole lowpass, and computer. I put a single pole 10hz low pass just as the cable comes into the house and it seems to help. I have more problems during the day, probably traffic. On a separate subject, I finally ordered some parts from digikey to take my VBB off the solderless bread board. Regards Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Marchal van Lare Subject: TEST - please IGNORE Date: Sun, 3 Jan 1999 17:07:18 -0500 TEST= _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: RADIOTEL@....... Subject: LEHMAN RESPONSE Date: Sun, 3 Jan 1999 23:22:42 EST Any List members I have just finished a Lehman seismograph, placed it in a plywood enclosure with form insulation on sides and top and a 10 watt light bulb. The seis is sitting on a cement slab that about 6 X 3 Feet and 4 inches deep. I am temporarily using a tupper-ware bowl filled with brake fluid to dampen the boom. I have the seis connected to an amp with about 1800 gain and a 15Hz filter. Watching the trace on the screen, there is a slow undulation wave pattern (almost straight across the screen). My problem (at least I assume it is a problem) is when I walk on the ground around the seis it generates a very large undulating wave pattern going off the screen and slowly returning until it finally returns to the wave pattern where it was before detection. I have tried minimum damping and maximum damping. Based on a geophone that I installed recently I assume this wave pattern is not normal. The geophone has essentially a straight wave pattern until detection and then the wave is closely spaced in the traditional pattern routinely seen from other. Thanks Jim Allen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: meredith lamb Subject: Re: LEHMAN RESPONSE Date: Sun, 03 Jan 1999 23:14:10 -0700 RADIOTEL@....... wrote: > My problem (at least I assume it is a problem) is when I walk on the ground > around the seis it generates a very large undulating wave pattern going off > the screen and slowly returning until it finally returns to the wave pattern > where it was before detection. I have tried minimum damping and maximum > damping. Based on a geophone that I installed recently I assume this wave > pattern is not normal. The geophone has essentially a straight wave pattern > until detection and then the wave is closely spaced in the traditional pattern > routinely seen from other. > Thanks > Jim Allen > Jim, What is the period of the undulations? Could be long period microseisms....mine in Denver are running roughly 6-8 seconds. Regardless......congratulations on building the seismo......hope future adjustments improve it to your satisfaction. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: meredith lamb Subject: Re: LEHMAN RESPONSE Date: Sun, 03 Jan 1999 23:29:01 -0700 Jim, Forgot to add.....of course walking around a seismo will make it tilt.....that is normal. With time you will recognize all the floor and car and etc., tilting "noise" as such. What you get out of the total system without inducing tilt is what counts. You should see activity all the time with the gain high enough....adjust it to the least gain, but, enough to see some activity most of the time on the computer screen. Then......you can adjust the damping oil levels. Damping with oil I've never done, but I suppose the only way is alot of experimentation....filling, lowering. It could be that you may need alot more fluid than you've already tried. Again.....Congratulations. Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "David A. Nelson" Subject: 2 M5+ New Zealand events Date: Mon, 4 Jan 1999 22:12:57 +1300 for those of u not on the PSN events list some info on the 2 recent NZ events........ M5.7 Near Rotorua upper central Nth Is NZ 144 km deep on the subducting slab under the volcanic zone M5.4 NW of Wellington City Sthrn end of the Nth Island (epic in Cook Strait) this 54 km deep event is also part of the subduction zone but at its southern end this region around cook strait has very complex tectonics as its the boundary between the subduction zone under and to the north of the Nth Island and the oblique slip zone in the south island that has thrust up the southern alps. the oblique slip Alpine Fault has a 3:1 ratio for every 3 metres of horizontal movement there is 1 metre of vertical movement. The subduction under the North Island is ~ 40 mm (4 cm 2 odd inches / yr) the convergence of the pacific plate against the indo-australian plate along the South Is's Alpine Fault is ~ 30 mm (3 cm 1.25 " / yr) 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 From: robert barns <75612.2635@..............> Subject: LEHMAN RESPONSE Date: Mon, 4 Jan 1999 10:36:16 -0500 Jim Allen, My Lehman behaves pretty much as you describe. It sits on the concrete= floor of my basement. If I walk within 5 feet of it, I see a fairly larg= e signal. Within 2 feet, it goes off scale. A Lehman is very sensitive to tilt and these signals are undoubtedly du= e to bending of the concrete floor. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Norman Davis WB6SHI Subject: Re: LEHMAN RESPONSE Date: Mon, 04 Jan 1999 08:03:55 .. > A Lehman is very sensitive to tilt and these signals are undoubtedly due >to bending of the concrete floor. >Bob Barns I'll drink to that. I had mine in the back of the garage. On the outside is sat on a slab that had been poured around the outside like a sidewalk. Whenever the ground got wet and swelled the slab would tilt and eather bottom out the lehman or run it out of the coil. I moved it into the garage and that stoped that. Next project... Slab buy it self away from the whole house and garage. Norman Davis WB6SHI Shingle Springs, Ca normd@............. http://www.directcon.net/normd/index.htm _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Lahr Subject: Re: Update on Dominica Date: Mon, 4 Jan 1999 12:58:27 -0700 (MST) Hi Ed, Welcome back! The Hill reference is: BSSA, August 1976, v 66, pg 1159-1172. John _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: Lehman tilt sensitivity Date: Mon, 4 Jan 1999 14:31:55 -0600 (CST) Jim, Congratulations! Some thoughts on your Lehman horizontal seismometer: (I have edited together some previously posted information; you may already have seen this) The Lehman is a "real-world-boys'" version of the Columbia-Sprengnether S5000 long-period, of which there are over 1000 in use; Meredith has a set; but I think there are others out there in the PSN. I have scanned a pictorial drawing of it to my web site on the psn info page. http://www.eas.slu.edu/People/STMorrissey/ stmmisc.html Some formulae of interest for the horizontal pendulum: (assuming that the restoring force by the hinges and/or pivot are minimal): The natural period: Tn = 2*pi*sqrt(l/(g*sine i)) where l is the boom length in cm, g=980cm/sec^2, i is the angle that the boom makes wrt the horizontal, measured in radians, (where sine i = i). For example, a 40 cm boom hanging vertically as a simple pendulum ( an angle of 90 degrees) has a period of 1.3 seconds, likr a SG. (a one second clock pendulum is 24.8 cm). When tilted horizontally to about 4 degrees, the period is 5 seconds. At about a 1 degree angle (sine i = 360deg/(2*pi) ), it is 10 seconds, and at about 0.23 deg. it is 20 seconds. So the period is changing with inverse of the square root of the angle, which is why long periods are so unstable. But unstable also means sensitive to smaller ground motions, which is why geophones fall short for LP sensitivity. So the stability question for a horizontal seismometer depends mostly on the mechanical period and the working range of the velocity coil; ie how far it can drift before touching. The old S5000s that I operate at 15 seconds in vaults rarely need to be recentered. (the working range is +,- 5mm for these horizontals). Years ago we ran them at 30 seconds, and had to center them about every other month. I understand that most Lehmans operate at 10 seconds give or take, but that some can be workable at 20 seconds with more frequent adjustment. Of course, the quality of the base, the rigidity of the boom support, and the stability of the pier then become a major concerns. Also, thermal effects on the base and frame of the instrument can cause major drifting. I don't have any information on the actual sensitivity of the Lehman designs that are in use. But for comparison to the S5000s I am operating at 15 seconds, which have a 32 tpi (turns per inch) leveling screw, about 1/100th turn (the leveling knob happens to have about a 100 mm circumference) is about 16 microradians, and moves the mass about 1mm. One can calculate how much the mass should move when tilted at a given period. This is a useful calculation for the tilt sensitivity of the horizontal pendulum (which can be used to calibrate the displacement detector) z = (g * Tn^2 / 4 * pi^2) * phi where z is the horizontal displacement of the mass, Tn is the natural period, and phi is the tilt of the base at right angles to the boom, again measured in radians. From my example above about the S5100: the base is 500 mm, so the tilt from 1/100 turn of the screw ( which is 0.008 mm) is 0.008/500 = 0.000016 radian. If Tn = 15 seconds, the mass will move 0.88 mm, which is close to my approximation. Evaluating this on my STM-8 horizontal, with l = 40 cm, and Tn = 10 seconds, 1/12 turn of the 28 tpi leveling screw is 0.9mm/12 = 0.075mm; the base width is 130mm, so the tilt is 0.075/130 = 0.00058 radians. This calculates to an offset of the mass of 1.43 cm, which is about what I measure. At 20 seconds, the offset is about 4 times, or 5.7 cm. Two points are clear: the stability is inversely proportional to the square of the period, or conversely, the sensitivity increases with square of the period. And the amount of the mass is not a consideration for the period or the displacement sensitivity. As long as it is significantly greater (like 10x) than the weight of the boom, it will work. And a final thought: I would forgo the hydraulic damping and simply use resistive damping with the main coil by shunting it with an appropriate resistor, which is what is done in modern seismology. The value of the resistor can be readily calculated; the voltage loss of the resistive damping is easily made up for with additional gain of the preamplifier. You can also add a separate moving coil/ magnet to accomplish the damping. Some LP high-gain sensors have a 100 000 ohm signal coil, which won't pass enough current to damp the seis, and a standard 500 ohm coil, for which the damping is calculated. For your fconvenience, I will re-post the formulas for calculating damping with a moving coil. One last note: since the LP horizontal IS so tilt sensitive, and will wander off scale at most "practical" sites, one could consider using a single high-pass filter at the input to the recording amplifier, like 1000 uf with 1 megohm, which will remove the long period drift that even a moving (velocity) coil will produce, and allow higher gains in the 1 to 20 second range. regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: Lehman damping Date: Mon, 4 Jan 1999 14:33:14 -0600 (CST) Here is an edited repeat of a previous mote about damping seismometers: Re electromagnetic damping: Most moving coil seismometers only use resistive damping. If properly calculated, no other damping is needed or should be used. Damping is generally expressed in relation to what is needed for "critical" damping, which means that after a step input, the output returns to a zero output voltage as rapidly as possible without overshooting. This damping has a value of 1. But it has a price, namely significant loss of the signal in the damping resistor. So generally damping is set at 0.8 of critical, which cuts the loss by about half, but the overshoot to an impulse input is minimal. Much less than 0.8, the natural period of the seismometer will dominate the response. On the other hand, if a fairly broad response is desired, and the seis and the amplifier have enough output and/or gain, damping as high as 2 can be used. Note that actually calculating the proper resistor depends on how much you know about the geophone or seismometer. The manufacturers data will sometimes even give the value for critical damping. But if the geophone is a mystery device, a generally good approximation is to measure the resistance of the coil and use that value for the damping resistor. To calculate the value of the damping resistor to be used, one first has to know or determine the open circuit damping, called Bo. It is the mechanical air-dashpot function of the coil movement, and is often listed in the specifications for the seismometer. For most seismometers, it ranges from 0.2 to 0.4, where a value of 0.8 is for critical damping. It can also be determined from the logrithmic decrement of the free oscillations of the undamped seismometer. (write for details on logrithmic decrement; you need a recorder or oscilloscope to do it. It involves measuring the successive amplitudes of undamped oscillations). Then the motor constant and resistance of the main coil have to be determined or found in the specifications. The electromagnetic damping Bem needed is determined by subtracting the Bo from the required total Bt. Bem = Bt - Bo (If you don't know your Bo, use a value of 0.3) Then the damping resistor is calculated by: Bem = G^2 / (2*omega*M*(Rs + Rd), or Rd = [G^2 / (Bem*2*omega*m)] - Rs Where Bem is the electromagnetic damping, G is the main coil constant, omega is the angular frequency, equivalent to 2*pi/Tn, where Tn is the natural period, and M is the mass. For an L4-C, with a 5500 ohm coil, with G = 270 V/m/sec, Bo = 0.27, we want Bt to be 0.77, so Bem = 0.5, M = 1 kgm, omega = 2*pi, we calculate a damping resistor Rd of 6102 ohms for critical damping. For an S5000 Long Period Seis, with a 500 ohm coil, G = 100 V/m/sec, Bo = 0.1, we want a flatter response with Bt = 1, so Bem = 0.9, omega = 2*pi/15 (seconds), M = 11 kg, we calculate a resistor of 705 ohms for Bt = 1 (the LP is over damped for a broader response). For an HS-1 4.5 hz geophone with a 1250 ohm coil, G = 41 V/m/sec, and Bo = 0.28; we want critical damping with Bt = 0.8, so Bem = 0.52, omega = 2*pi*4.5 (hz), M = 0.022kg, we calculate Rd = 1348 ohms. This method of damping is the only method currently being used on velocity sensors. The method is so exact that often the resistor for Rd is installed inside the smaller geophones at the factory. Metal-film resistors are used for lower noise. When one is connecting a seismometer to an amplifier with a low input impedance Ra, that value is in parallel with the seismometer, so must be taken into account. So if Ra = 10k ohms, and Rd is to be 5k ohms, the actual resistor to be used is Rs = Rd*Ra/(Ra-Rd), or in this case Rs = 10k ohms. Generally very high input impedance amplifiers are not used because of noise considerations, so this detail is often overlooked. Unfortunately I have no idea what the constants for a Lehman might be. I note that the coil is 1/4 pound of # 34 wire which has 8310 feet per pound and 2168 ohms per pound at 20 deg.C. So assuming the coil is about 500 ohms, I would try a damping resistor of about 1000 ohms, unless you already know the constant G of the main coil and can calculate the value. With this type of damping, the response should be flat to velocity from roughly the natural period to whatever low-pass filter you have in your amplifier. (BTW another place to check to see if the shorter p-wave phases are being filtered out). The drawback of resistive damping, other than the loss of part of the signal from the coil (made up for with less attenuation in the recording circuitry) is that it is dissipative, and makes noise. This is the reason it is not used in the VBB configuration, where the damping is a dynamic process in the feedback loop. The noise from the damping resistor is primarily Johnson or thermal noise, which can be estimated, as well as 1/f noise. A low noise metal film resistor does help. This noise is generally not a problem for most seismometer sites. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: RADIOTEL@....... Subject: Re: Lehman tilt sensitivity Date: Mon, 4 Jan 1999 23:29:25 EST Meredith, Norman,Bob and Sean-Thomas Your suggestions and experiences that you shared were very helpful. I had not realized that the lehman would be so sensitive (even showing those microseisms). Next weekend I will connect a varible resistor (10 turn 0 -30k variable wire-wound resistor) across the coil which is 9.7k. That certainly should dampen it adequately (if I am reading the formulas given in Sean- Thomas' response, right? I will also follow the recommendation by Sean-Thamas to use a high pass filter to help remove the long period drift. Jim Allen radiotel@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Francesco" Subject: R: Station near you. AutoDRM Date: Tue, 5 Jan 1999 12:37:09 +0100 Hello Arie. I had download your C programm for AUTODRM, but I'haven't understand a = thing. I have required a file to PIDC ORG for example. I have received the = mail, with inserted the file in GSE2.0 format, but not attached. =20 This way, I have a file of mail (uencode, ecc.ecc.) but not a named file = available to convert with your program. =20 How do I have to do? =20 Regards Francesco Nucera - I.ES.N. PSN ITALY
Hello Arie.
I had download your C programm for = AUTODRM, but=20 I'haven't understand  a thing.
 
I have required a file to PIDC ORG = for example.=20 I have received the mail, with inserted the file in GSE2.0 format, but = not=20 attached. 
This way, I have a file of mail (uencode, ecc.ecc.) = but not=20 a named file available to convert with your program. 
How do I = have to=20 do? 
Regards
 
Francesco Nucera -  = I.ES.N.  PSN=20 ITALY
From: Arie Verveer Subject: Re: R: Station near you. AutoDRM Date: Tue, 05 Jan 1999 21:23:02 +0800 Hi Francesco > I had download your C programm for AUTODRM, but I'haven't understand a thing.I have required > a file to PIDC ORG for example. I have received the mail, with inserted the file in GSE2.0 > format, but not attached. > This way, I have a file of mail (uencode, ecc.ecc.) but not a named file available to convert > with your program. > How do I have to do? If your mail program has an edit feature then you could open the AutoDRM message, mark the text, and then go to your edit menu and press the copy option. Then go to a text editor and paste the document. Then you should be able to save the data as a file. This may be one solution. Are you running Eudora lite ? I do understand its a strange way to get data but once you master the technique its really worth it. This is especially true when you are in an area where data is hard to get. If you have any more troubles please let me know. Its worth persevering with the AutoDRM, especially the method of getting the data. All the best, a please let me know how it worked out. Arie Today I used the AutoDRM to confirm a small event as coming from a mining area 140km from my station. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: RADIOTEL@....... Subject: LEHMAN RESPONSE Date: Tue, 5 Jan 1999 22:13:31 EST Meredith, Norman, Bob and Sean-Thomas My new lehman picked up its first earthquake today. Meridith,Norman and Bob's suggestions that the undulations and tilt were normal was correct. I did need more damping as Meridith suggested and I took Sean-Thomas' suggestion to get rid of the oil damping. The installation of resistive damping made a world of difference especially using a variable resistor which I can adjust from inside the house while the seismo is outside. When I dont get near the seismo I now find that the wave trace is essentially straight. Next weekend I plan to add a 1000 uf cap and 1 meg res. filter to the amp input to ensure that drift will be minimal. Your help and encouragement was invaluable. Jim Allen radiotel@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Arie Verveer Subject: Year 2000 Calendar Date: Wed, 06 Jan 1999 14:21:50 +0800 Hi All, I was looking up some information on the year 2000 calendar dates when I came across this interesting bit information. The years 1876, 1944, 1972, 2000, 2028 all have the identical calendar. The 1st of those years all start on a saturday and years following are in the calendar sequence. So just set your old computer clock to -28 years and all will be well? Just remember to add 28 years. Just an observation. - Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Wayne Abraham J73WA Subject: Re: Year 2000 Calendar Date: Wed, 06 Jan 1999 07:51:35 -0400 Arie I thought the calendar repeated itself every 11 years. Wayne Arie Verveer wrote: > Hi All, > I was looking up some information on the year 2000 calendar dates > when I came across this interesting bit information. > > The years 1876, 1944, 1972, 2000, 2028 all have the identical calendar. > The 1st of those years all start on a saturday and years following are in the > calendar sequence. > So just set your old computer clock to -28 years and all will be well? > Just remember to add 28 years. > > Just an observation. - 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 From: Brett Nordgren Subject: Re: Year 2000 Calendar Date: Wed, 06 Jan 1999 09:25:58 -0500 Arie, I may be way wrong, but I thought, unlike the other four years you mention, that 2000 is *not* going to be a leap year. Does anyone remember for sure? Brett At 02:21 PM 1/6/99 +0800, you wrote: >Hi All, >I was looking up some information on the year 2000 calendar dates >when I came across this interesting bit information. > >The years 1876, 1944, 1972, 2000, 2028 all have the identical calendar. >The 1st of those years all start on a saturday and years following are in the >calendar sequence. >So just set your old computer clock to -28 years and all will be well? >Just remember to add 28 years. > >Just an observation. - 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 From: bc Subject: Re: Year 2000 Calendar Date: Wed, 06 Jan 1999 09:49:42 -0500 At 09:25 AM 1/6/99 -0500, you wrote: >Arie, > >I may be way wrong, but I thought, unlike the other four years you mention, >that 2000 is *not* going to be a leap year. Does anyone remember for sure? > >Brett Typically century marks are not leap years. I'm not absolutely sure about 1000 year marks but i don't remember them being treated special so my best educated guess is that it is not a leap year. However, I'm not sure I'm actually following this thread? Is it the contention that by advancing one's date to the year 2028 that we will avoid a year 2000 problem? If that's the assumption than I'm afraid its incorrect. If not, my apologies for sticking my nose in where it doesn't belong (a bad habit I seem to have) bc > > >At 02:21 PM 1/6/99 +0800, you wrote: >>Hi All, >>I was looking up some information on the year 2000 calendar dates >>when I came across this interesting bit information. >> >>The years 1876, 1944, 1972, 2000, 2028 all have the identical calendar. >>The 1st of those years all start on a saturday and years following are in the >>calendar sequence. >>So just set your old computer clock to -28 years and all will be well? >>Just remember to add 28 years. >> >>Just an observation. - 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) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: bzimmerman@............ Subject: Re: Year 2000 Calendar Date: Wed, 06 Jan 1999 09:59:03 -0500 (EST) The calender on my desk shows 29 days in February 2000. Brian Zimmerman _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: bc Subject: Re: Year 2000 Calendar Date: Wed, 06 Jan 1999 10:19:47 -0500 At 09:59 AM 1/6/99 -0500, you wrote: > >The calender on my desk shows 29 days in February 2000. > >Brian Zimmerman I stand corrected on 2 counts. First, I understand the thread now. Its to correct OLD calendar clock systems to just get the correct day of the week. Second, it is a leap year. The following is from Leap Year FAQ at http://aa.usno.navy.mil/AA/faq/docs/faq1.html The Rule According to the Gregorian calendar, which is the civil calendar in use today, years evenly divisible by 4 are leap years, with the exception of centurial years that are not evenly divisible by 400. Therefore, the years 1700, 1800, 1900 and 2100 are not leap years, but 1600, 2000, and 2400 are leap years bc _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Canie Brooks Subject: Re: Year 2000 Calendar Date: Wed, 06 Jan 1999 08:29:22 -0800 At 09:25 AM 1/6/99 -0500, Brett Nordgren wrote: >Arie, > >I may be way wrong, but I thought, unlike the other four years you mention, >that 2000 is *not* going to be a leap year. Does anyone remember for sure? > >Brett I'll also add my 2 cents worth - I'm a programmer and this is one of the issues creating part of the 'millenium bug' ! The year 2000 IS a leap year and lots of programs, operating systems don't recognise it as such.. One of the big things to fix... Canie > > >At 02:21 PM 1/6/99 +0800, you wrote: >>Hi All, >>I was looking up some information on the year 2000 calendar dates >>when I came across this interesting bit information. >> >>The years 1876, 1944, 1972, 2000, 2028 all have the identical calendar. >>The 1st of those years all start on a saturday and years following are in the >>calendar sequence. >>So just set your old computer clock to -28 years and all will be well? >>Just remember to add 28 years. >> >>Just an observation. - Arie >> >> >> _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Wayne Abraham J73WA Subject: [Fwd: MessageShip Response to MSG_ID=All] Date: Wed, 06 Jan 1999 15:46:54 -0400 Arie This is a message I received when I tried a request from autodrm. Just thought I would pass it on. Wayne From: John Hernlund Subject: Re: Year 2000 Calendar Date: Wed, 06 Jan 1999 12:56:44 -0700 (MST) On Wed, 6 Jan 1999, bc wrote: > At 09:25 AM 1/6/99 -0500, you wrote: > >I may be way wrong, but I thought, unlike the other four years you mention, > >that 2000 is *not* going to be a leap year. Does anyone remember for sure? > >Brett > Typically century marks are not leap years. I'm not absolutely sure about > 1000 year marks but i don't remember them being treated special so my best > educated guess is that it is not a leap year. However, I'm not sure I'm > actually following this thread? Is it the contention that by advancing > one's date to the year 2028 that we will avoid a year 2000 problem? If > that's the assumption than I'm afraid its incorrect. If not, my apologies > for sticking my nose in where it doesn't belong (a bad habit I seem to > have) I think the only rule for leap years is an extra day in February (the 29th) every four years. This is because the year is approximately 365 and 1/4 days long. I think we also have leap seconds every year, but I am not sure if that is just rumor or truth... For those using WWV though, these leap seconds could be a hassle; that is, if they exist. Also, the only thing special anyone is doing for 2000 that I have heard about is going to Jerusalem and vowing to die in a violent fight to prepare the way for the second coming... I have a feeling that this type of thing will be a problem for governments worldwide this year... ****************************************************************************** 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 From: Greg Subject: Re: [Fwd: MessageShip Response to MSG_ID=All] Date: Wed, 06 Jan 1999 13:27:53 -0700 Wayne Abraham J73WA wrote: > This is a message I received when I tried a request from autodrm. Just > thought I would pass it on. I'm not Arie, but I'm guessing you wanted the binary file sent to you directly? If so it's possible you requested it wrong. It looks like the server put it on a FTP server for you to download. From what it says, try this: ftp into pidc.org username anonymous with an email address for the password cd to /pub get 5264365.msg.Z Then you gotta get tar for DOS unless you have Linux or Solaris or something. The Z means the file is compressed. Check out gnu.org if you need it. It's probably in lots of other places also. It is there. I just checked. Good luck, Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Greg Subject: Re: Year 2000 Calendar Date: Wed, 06 Jan 1999 13:34:48 -0700 John Hernlund wrote: > long. I think we also have leap seconds every year, but I am not sure if that > is just rumor or truth... For those using WWV though, these leap seconds > could be a hassle; that is, if they exist. I found this just now: http://www.dtic.mil/doctrine/jel/doddict/data/l/03463.html "Leap Second (DOD) A second of time that is added to or removed from Coordinated Universal Time (UTC) to keep UTC within 0.9 seconds of UT1 (see Universal Time). Leap Seconds are normally introduced at the end of June or December if required. The decision to introduce a Leap Second is announced by the International Time Bureau (Bureau International de l'Heure, or BIH) approximately eight to ten weeks in advance. See also Coordinated Universal Time." Neat little military biased dictionary. I remember hearing other people talking about adding them at one of my former jobs. I've never been involved myself. I would think that WWV would handle this pretty much automatically. Same for GPS. It might take a full minute or two for the computer to catch up to the signal time though. ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Subject: Re: Year 2000 Calendar Date: Wed, 6 Jan 1999 14:49:38 -0600 (EST) See http://tycho.usno.navy.mil/leapsec.html for a detailed description of the leap second and how it affects GPS wwV etc. Jim Hannon http://soli.inav.net~jmhannon/ 42,11.90N,91,39.26W WB0TXL On Wed, 6 Jan 1999, Greg wrote: > John Hernlund wrote: > > > long. I think we also have leap seconds every year, but I am not sure if that > > is just rumor or truth... For those using WWV though, these leap seconds > > could be a hassle; that is, if they exist. > > I found this just now: > http://www.dtic.mil/doctrine/jel/doddict/data/l/03463.html > > "Leap Second > > (DOD) A second of time that is added to or removed from Coordinated > Universal Time (UTC) to keep UTC within 0.9 seconds of UT1 (see > Universal Time). Leap Seconds are normally introduced at the end of June > or December if required. The decision to introduce a Leap Second is > announced by the International Time Bureau (Bureau International de > l'Heure, or BIH) approximately eight to ten weeks in advance. See also > Coordinated Universal Time." > > Neat little military biased dictionary. I remember hearing other people > talking about adding them at one of my former jobs. I've never been > involved myself. > > I would think that WWV would handle this pretty much automatically. Same > for GPS. It might take a full minute or two for the computer to catch up > to the signal time though. > > ,Greg > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Greg Subject: Re: Year 2000 Calendar Date: Wed, 06 Jan 1999 14:14:31 -0700 jmhannon@............. wrote: > > See http://tycho.usno.navy.mil/leapsec.html for a detailed description of > the leap second and how it affects GPS wwV etc. That page mentions that GPS is not corrected for some reason, but it doesn't mention WWV. I did find that also. WWV is corrected (I hope that is correct) ;) GPS is off by about 13 seconds right now. http://www.bldrdoc.gov/timefreq/pubs/sp432/s_appa.htm What time is it? ;) ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Kevin J. Rowett" Subject: Re: Year 2000 Calendar Date: Wed, 06 Jan 1999 13:32:45 -0800 >I would think that WWV would handle this pretty much automatically. Same >for GPS. It might take a full minute or two for the computer to catch up >to the signal time though. WWV distributes time on the UTC scale, which includes leap second insertions. GPS time is not on the UTC scale because it doesn't insert any (more) leap seconds. The GPS messages do contain both an indication that a leap second will be inserted into the UTC scale at the end of the month, and how many have been inserted so far. This allows a GPS receiver to produce a pretty accurate estimate of UTC directly. I noted any more leap seconds because when GPS time was first synchronized in 1980, 19 leap seconds were already inserted, and GPS included those. So GPS time is now 13 seconds ahead of UTC. KR _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Greg Subject: Re: Year 2000 Calendar Date: Wed, 06 Jan 1999 14:40:06 -0700 "Kevin J. Rowett" wrote: > So GPS time is now 13 seconds ahead of UTC. Larry C., is SDR using the offset in it's time with your GPS reciever? It would probably be pretty obvious if it's not. It would be kinda fun to watch it handle the leap second as it happens, if it does look at that. ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Kevin J. Rowett" Subject: Re: Year 2000 Calendar Date: Wed, 06 Jan 1999 14:04:37 -0800 At 01:40 PM 1/6/99 , you wrote: >"Kevin J. Rowett" wrote: > >> So GPS time is now 13 seconds ahead of UTC. > >Larry C., is SDR using the offset in it's time with your GPS reciever? >It would probably be pretty obvious if it's not. It would be kinda fun >to watch it handle the leap second as it happens, if it does look at >that. It was fun, especially since the USNO clock 'tick.usno.navy.mil' didn't update properly (tick did, clepsydra.dec.com didn't). BTW, the proscribed insertion method is to duplicate the last second of the month, hence the leap second was in 1998, *not* 1999. Some clocks will display 23:59:59 23:59:59 24:00:00. Some display the dup :59 as :60. You'll have to wait 17 months and a few days now to see the next one mostly likely. Check with IERS in July. KR _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Re: Year 2000 Calendar Date: Wed, 06 Jan 1999 14:05:22 -0800 At 02:40 PM 1/6/99 -0700, you wrote: >"Kevin J. Rowett" wrote: > >> So GPS time is now 13 seconds ahead of UTC. > >Larry C., is SDR using the offset in it's time with your GPS reciever? >It would probably be pretty obvious if it's not. It would be kinda fun >to watch it handle the leap second as it happens, if it does look at >that. > >,Greg When I added the GPS support too SDR I didn't notice a 13 second offset problem, so the ONCORE GPS receiver must be handling this.... -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Kevin J. Rowett" Subject: Re: Year 2000 Calendar Date: Wed, 06 Jan 1999 15:23:48 -0800 >>> So GPS time is now 13 seconds ahead of UTC. >> >>Larry C., is SDR using the offset in it's time with your GPS reciever? >>It would probably be pretty obvious if it's not. It would be kinda fun >>to watch it handle the leap second as it happens, if it does look at >>that. >> >>,Greg > >When I added the GPS support too SDR I didn't notice a 13 second offset >problem, so the ONCORE GPS receiver must be handling this.... It does, as long as it has satt lock, and the ephemeris acquired during the leap second event. Most GPS receivers output time (the PVT message) on the UTC scale. You have to fiddle with them in propietary ways to get them to output the true GPS time. KR _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: Year 2000 Calendar Date: Wed, 06 Jan 1999 16:47:05 -0700 (MST) On Wed, 6 Jan 1999, Kevin J. Rowett wrote: > So GPS time is now 13 seconds ahead of UTC. I wonder what happens to files that are archived from seismograph stations receiving GPS time correction then, are they all normalized to UTC after retrieving the data??? ****************************************************************************** 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 From: "Kevin J. Rowett" Subject: Re: Year 2000 Calendar Date: Wed, 06 Jan 1999 16:05:56 -0800 At 03:47 PM 1/6/99 , you wrote: >On Wed, 6 Jan 1999, Kevin J. Rowett wrote: >> So GPS time is now 13 seconds ahead of UTC. > > I wonder what happens to files that are archived from seismograph stations >receiving GPS time correction then, are they all normalized to UTC after >retrieving the data??? I think some confusion exists here. GPS receivers normally issue time messages (the PVT message) using the UTC scale, which includes leap seconds. The time "flowing down" from the satt is on the GPS time scale which doesn't include leap seconds past 1980. The receiver "subtracts" the number of leap seconds (it's a lot more complicated than this, read the GPS spec!) presently indicated in the difference between UTC and GPS time. As Larry noted, his use of the Moto oncore GPS receiver is the normal one -> UTC time scale. The original point was WWV and GPS run on different time scales. The subsequent point is that GPS receivers normally are the devices that apply the correction. Now, if you want to talk about being able to set an alarm clock for a future event, that's an interesting discussion. What interval should I set the timer for? :-). KR _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Walt Williams " Subject: PSN-L: Solar Super Flares Date: Wed, 6 Jan 1999 17:20:43 -0800 All, Little off-topic post, but very interesting. FYI. Cross posted from the Search for ExtraTerrestrial Intelligence - League (SETI-L) open list. Walt Williams, 99.01.06 PSN Stn 63 dfheli@.............. ============================================ Date: Wed, 6 Jan 1999 22:39:40 GMT From: Ron Baalke To: astro@.................... Subject: Yale Astronomers Study Superflares on Stars Just Like Our Sun Sender: owner-astro@......................... Reply-To: Ron Baalke Subject: Re: Year 2000 Calendar Date: Thu, 07 Jan 1999 09:49:35 +0800 Hi All, The year 2000 is a LEAP year. Our passage through the seasons is called a "tropical" year of 365.24.. days long. This awkward fraction 0f 0.24... days is nearly a 1/4 of a day. So Pope Gregory on the advice of the astronomer Clavius adopted this solution. Every forth year we add a day (leap year). To correct for the errors in the fraction we make the century years that are divisible by 400 a leap year. (There is also a 4000 year correction). So 1900 was not a leap year but 2000 will be a leap year. Calendars that are the same: Look identical (other than festivals) 1) ..,1989, 1995, 2006, 2017 (not a leap year) 2) ..,1990, 2001, 2007, 2018 "" 3) ..,1991, 2002, 2013, 2019 "" 4) ..,1997, 2003, 2014, 2025 "" 5) ..,1998, 2009, 2015, 2026 "" 6) ..,1999, 2010, 2021, 2027 "" 7) ..,2005, 2011, 2022, 2033 "" 8) ..,1928,1984, 2012, 2040 (LEAP YEAR) 9) ..,1968,1996, 2024 L 10) ..,1952,1980, 2008,2036 L 11) ..,1908,1964, 2020,2048 L 12) ..,1948,1976, 2004,2032 L 13) ..,1904,1960, 2016,2044 L 14) ..,1944,1972, 2000,2028 L ******** Ragards Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: Year 2000 Calendar: simple algorithm for leap yrs. Date: Wed, 06 Jan 1999 19:25:46 -0700 (MST) A simple algorithm for determining leap years would simply be to see if the year is divisible by four and the result be a whole number... eg. 2000/4 = 500 leap 2001/4 = 500.25 not 2002/4 = 500.5 not 2003/4 = 500.75 not 2004/4 = 501 leap 2005/4 = 501.25 not etc., as long as they keep doing it every four years... ****************************************************************************** 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 From: "Kevin J. Rowett" Subject: Re: Year 2000 Calendar: simple algorithm for leap yrs. Date: Wed, 06 Jan 1999 18:59:01 -0800 At 06:25 PM 1/6/99 , you wrote: >A simple algorithm for determining leap years would simply be to see if the >year is divisible by four and the result be a whole number... > >eg. 2000/4 = 500 leap > 2001/4 = 500.25 not > 2002/4 = 500.5 not > 2003/4 = 500.75 not > 2004/4 = 501 leap > 2005/4 = 501.25 not >etc., as long as they keep doing it every four years... Yet, 1900/4 = 475 "evenly divisible", 1900/400 = 4.75; 4 with a remainder of 75 (1900 wasn't a leap year). 2100 is similiar. KR _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Mark Robinson" Subject: Re: Year 2000 Calendar Date: Thu, 7 Jan 1999 16:39:31 +1300 Just a wee vote for Arie's leap year algorithm. What he states is what I was taught at univeristy while learning to program. Shame that certain more successful programmers didn't. Happy New Year Mark G Robinson | ZL2TOD | other@............... Box 8770, Auckland 1035, New Zealand Phone +64-9-846-3296 | Fax +64-9-849-7408 ------------------------------------------------ 07 Jan 1924 George Gershwin composes Rhapsody in Blue. 07 Jan 1952 Ike offers to accept GOP Presidential Nomination. ----- Original Message ----- From: Arie Verveer To: PSN-L Mailing List Sent: Thursday, 7 January 1999 14:49 Subject: Re: Year 2000 Calendar >Hi All, > >The year 2000 is a LEAP year. Our passage through the seasons is >called a "tropical" year of 365.24.. days long. This awkward fraction >0f 0.24... days is nearly a 1/4 of a day. So Pope Gregory on the advice of >the astronomer Clavius adopted this solution. Every forth year we add a >day (leap year). To correct for the errors in the fraction we make the century >years that are divisible by 400 a leap year. (There is also a 4000 year >correction). So 1900 was not a leap year but 2000 will be a leap year. > >Calendars that are the same: Look identical (other than festivals) > > 1) ..,1989, 1995, 2006, 2017 (not a leap year) > 2) ..,1990, 2001, 2007, 2018 "" > 3) ..,1991, 2002, 2013, 2019 "" > 4) ..,1997, 2003, 2014, 2025 "" > 5) ..,1998, 2009, 2015, 2026 "" > 6) ..,1999, 2010, 2021, 2027 "" > 7) ..,2005, 2011, 2022, 2033 "" > > 8) ..,1928,1984, 2012, 2040 (LEAP YEAR) > 9) ..,1968,1996, 2024 L >10) ..,1952,1980, 2008,2036 L >11) ..,1908,1964, 2020,2048 L >12) ..,1948,1976, 2004,2032 L >13) ..,1904,1960, 2016,2044 L >14) ..,1944,1972, 2000,2028 L ******** > >Ragards 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 From: Dewayne Hill Subject: Y2K Date: Thu, 07 Jan 1999 08:11:14 -0700 I'm not one that gets upset very easily but I think all of the E-Mails about Y2K problems would be better communicated on one of the Y2K user groups rather that filling up the PSN server and my mail box. Regards, A nagging old man Dewayne (n0ssy) & Linda (n0uqf) Hill Westminster, Colorado USA 39.83569n 105.06270w. Elev 5460ft. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Roger Griggs Subject: Re: Year 2000 Calendar Date: Thu, 07 Jan 1999 16:46:08 -0800 John, Our Electric Transmission Control system log showed a leap second added via GPS TIME at 16:00 PST, Dec 31, 1998. This would have been 00:00 Jan 01, 1999 GMT. And yes, in a realtime control system, these leap seconds are a hassle. Roger At 12:56 PM 1/6/99 -0700, you wrote: >On Wed, 6 Jan 1999, bc wrote: >> At 09:25 AM 1/6/99 -0500, you wrote: >I think the only rule for leap years is an extra day in February (the 29th) >every four years. This is because the year is approximately 365 and 1/4 days >long. I think we also have leap seconds every year, but I am not sure if that >is just rumor or truth... For those using WWV though, these leap seconds >could be a hassle; that is, if they exist. > >Also, the only thing special anyone is doing for 2000 that I have heard >about is going to Jerusalem and vowing to die in a violent fight to prepare >the way for the second coming... I have a feeling that this type of thing >will be a problem for governments worldwide this year... > >*************************************************************************** *** > > 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 From: peaches@............ (Donna Whitaker) Subject: USGS Geological Hazards Report Date: Thu, 7 Jan 1999 15:06:37 -1000 (HST) News Release U.S. Department of the Interior U.S. Geological Survey Office of the Eastern Regional Geologist 953 National Center Reston, VA 20192 Release: Upon Receipt (Jan. 7, 1999) Contact: Diane Noserale dnoseral@........ 703-648-4333 Fatalities Increase in 1998, but . . . Earthquake Death Toll Still Below Long-Term Average Note to editors: Because of the nature of earthquake data collection, information on these events should be considered preliminary. We will issue an update if necessary. At least 8,928 people were reported killed from earthquakes world wide in 1998, according to the U.S. Geological Survey National Earthquake Information Center (NEIC) in Golden, Colo. Although this is a three-fold increase over the 1997 toll of 2,907, and a twenty-fold increase over the 1996 total of 419 deaths, it is still under the long-term average of about 10,000 earthquake-related deaths in the world each year. "This is the 5th consecutive year in which the death toll has been below average world wide," said Waverly Person, Director of the USGS NEIC. "The border area of Afghanistan and Tajikistan bore the brunt of fatalities in two events (at least 6,323 fatalities), neither of which was the strongest earthquake for the year or even classified as a major earthquake," Person explained. The strongest earthquake in 1998, one of only two great earthquakes recorded in the world in 1998 (magnitude 8.0 or above), occurred on March 25 in the Balleny Islands region, between Australia and Antarctica. Its magnitude was 8.3. The other great earthquake occurred on Nov. 29 in the Ceram Sea, near Sulawesi, Indonesia. That earthquake's magnitude was 8.1 and at least 34 people were killed. Only ten earthquakes were classified as "major." Major earthquakes have a magnitude of 7.0-7.9. According to long-term records, an average of 20 major earthquakes occur in the world per year. "No fatalities occurred in the U.S. in 1998 from earthquakes; however two people were reported injured in the August 12, magnitude 5.3 earthquake in southern Santa Cruz County, California," said Person. Three earthquakes of magnitude 6.2 were the strongest recorded in the U.S. in 1998. All occurred in Alaska: July 9 in southern Alaska, Aug. 20 and Sept. 14 in the Aleutian Islands. "A magnitude 5.2 earthquake on the Ohio-Pennsylvania border on Sept. 25 generated the greatest number of inquiries to the NEIC. Although this earthquake did not cause very much damage, it was felt strongly throughout northern Ohio and most of Pennsylvania. It was also felt in Illinois, Indiana, Michigan, New Jersey, New York, and southern Ontario, Canada," said Person. "We continue to hear from many people throughout the world that earthquakes are on the increase. Although it may seem that we are having more earthquakes, this is not the case. In fact, earthquakes of magnitude 7.0 or higher have remained fairly constant throughout this century," Person noted. A partial explanation for the impression of increased earthquakes may be that in the last twenty years, we have definitely had an increase in the number of earthquakes USGS has been able to locate each year. This is because of the tremendous increase in the number of seismograph stations in the world and the many improvements in global communications. Besides enhancing public safety, this increase in the number of stations and the more timely receipt of data has allowed seismological centers to locate many small earthquakes which were undetected in earlier years, and we are able to locate earthquakes more rapidly. Also, because of the improvements in communications and the increased interest in natural disasters, the public now learns about more earthquakes. Also, the effect that earthquakes have when they strike is generally more pronounced. Although we have gained much knowledge in building safer structures, when earthquakes occur today, losses (both human and property) are greater in many areas of the world. This is not because the earthquakes are stronger; it is simply because the Earth's population is increasing and more property (much of it not built to withstand earthquakes) exists that can be destroyed in an earthquake. USGS estimates that several million earthquakes occur in the world each year. Many of these earthquakes go undetected because they occur in remote areas or have very small magnitudes. The USGS locates about 18,000 to 20,000 earthquakes each year (about 50 per day). Additional information on the year's earthquakes is available on the USGS NEIC Homepage at: http://wwwneic.cr.usgs.gov/ As the nation's largest water, earth and biological science and civilian mapping agency, the USGS works in cooperation with more than 2000 organizations across the country to provide reliable, impartial, scientific information to resource managers, planners, and other customers. This information is gathered in every state by USGS scientists to minimize the loss of life and property from natural disasters, to contribute to the conservation and the sound economic and physical development of the nation's natural resources, and to enhance the quality of life by monitoring water, biological, energy, and mineral resources. ### USGS ### This press release and in-depth information about USGS programs may be found on the USGS home page: http://www.usgs.gov. To receive the latest USGS news releases automatically by email, send a request to . Specify the listserver(s) of interest from the following names: water-pr; geologic-hazards-pr; biological-pr; mapping-pr; products-pr; lecture-pr. In the body of the message write: subscribe (name of listserver) (your name). Example: subscribe water-pr joe smith. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Steve Jones Subject: Re: Year 2000 Calendar Date: Thu, 07 Jan 1999 19:30:51 -0800 Larry Cochrane wrote: > > At 02:40 PM 1/6/99 -0700, you wrote: > >"Kevin J. Rowett" wrote: > > > >> So GPS time is now 13 seconds ahead of UTC. > > > >Larry C., is SDR using the offset in it's time with your GPS reciever? > >It would probably be pretty obvious if it's not. It would be kinda fun > >to watch it handle the leap second as it happens, if it does look at > >that. > > > >,Greg > > When I added the GPS support too SDR I didn't notice a 13 second offset > problem, so the ONCORE GPS receiver must be handling this.... > > -Larry Cochrane > Redwood City, PSN > > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L Just thought I'd add my .02 re: the "GPS offset". If you fire up a "cold" (non-initialized) Oncore (or any other, I suppose) GPS receiver, you can watch the offset correction from GPS time occur a few minutes after the receiver first acquires a complete time solution. It is simply a (currently) 13-second decrement in the seconds output message. From the Oncore tech manual: "...The UTC [GPS offset] parameters are broadcast by the satellites as a part of the almanac, which is repeated every 12.5 minutes...The value reported is the integer number of seconds between UTC and GPS time..." Steve Jones _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: CARRJJ@....... Subject: Assistance?? Date: Thu, 7 Jan 1999 21:45:06 EST Can anyone direct me to sources of information on seismic instruments, hardware and their application suitable for amateur or hobbyist level people? Joseph J. Carr POB 1099 Falls Church, VA 22041 CARRJJ@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Wayne Abraham J73WA Subject: Re: Assistance?? Date: Thu, 07 Jan 1999 23:07:03 -0400 Joseph Visit the PSN site at: http://psn.quake.net/ Wayne CARRJJ@....... wrote: > Can anyone direct me to sources of information on seismic instruments, > hardware and their application suitable for amateur or hobbyist level people? > > Joseph J. Carr > POB 1099 > Falls Church, VA 22041 > CARRJJ@....... > > _____________________________________________________________________ > > 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 From: JIm Hannon Subject: Re: Assistance?? Date: Thu, 07 Jan 1999 21:41:45 -0600 CARRJJ@....... wrote: > Can anyone direct me to sources of information on seismic instruments, > hardware and their application suitable for amateur or hobbyist level people? > > Joseph J. Carr > POB 1099 > Falls Church, VA 22041 > CARRJJ@....... > > Just start asking questions on this list. Also it is well worth the time to read the archives of the list at http://psn.quake.net/maillist.html#archives -- 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 From: barry lotz Subject: Re: Assistance?? Date: Thu, 07 Jan 1999 20:01:46 -0800 Hi Joe Scientific American - Amatuer scientist.( Older editions) Barry CARRJJ@....... wrote: > Can anyone direct me to sources of information on seismic instruments, > hardware and their application suitable for amateur or hobbyist level people? > > Joseph J. Carr > POB 1099 > Falls Church, VA 22041 > CARRJJ@....... > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Re: box to dominica Date: Thu, 07 Jan 1999 23:13:19 -0700 Meredith- I apologise for taking so long to get back to you on the subject, but now that I've been back from Dominica for a week, I figured I'd tell you just what happened to your box (I'll start with a short background for the blissfully innocent). [Meredith arrived at my USGS Golden, Colorado, office on Saturday afternoon, 19 Dec, the day before Jody and I departed for Dominica, with a large cardboard box, ~30x20x60 cm, i.e., 12x8x24 in, that was also quite heavy, ~10-15 kg, i.e., 20-30 lbs. When I saw how big his box was relative to the heavy-duty plastic shipping case I was planning to pack all the seismic equipment I was bringing to Dominica -- including a 3-channel amplifier board, an SDR board, a PC-LABS A/D board & manual from Larry Cochrane; a L-28 vertical geophone from Roger Vaught; an antenna mount from Rick Curtis; and a 3-component L-22 geophone on loan from USGS -- I suggested to Meredith that maybe I could leave the box itself and only pack the contents, but he did not look particularly enthusiastic about that idea.] It was only in my typically last-minute rush of packing the next morning a couple of hours before our departure that I looked in the box and realized that it contained many of the pieces in semi-kit form of a Lehman seismometer -- including what looked to my hasty inspection like a LARGE MAGNET -- and that all the components were carefully and securely packed in their respective bags and plastic jars. So I packed the whole box as it was in the shipping case and everything else fit in quite snugly as well, and I wrapped up the shipping case with meters of fiber tape so that it looked like a bandage-swathed plastic coffin holding a PVC Mummy from the petrochemical swamps of New Jersey industrial wasteland. However, as soon as we started to checkin at the Denver airport, the man at the counter wanted to know if the shipping case contained "any magnets". Since I have shipped literally tons of seismic equipment using the same shipping cases while chasing earthquakes with USGS and have never been questioned about their contents, I was, in terms of speaking the truth, caught with my pants down, and I answered that it contained one magnet weighing several pounds (i.e., half that many kilograms). That triggered several long telephone consultations with various airline experts and other officials during which I was questioned -- causing me to babble about working for the USGS even though all our other statements indicated that we were on a personal vacation -- and which included discussions of "compass checks". That made me think that perhaps Meredith's supermagnet might misnavigate us to Cuba rather than Dominica. And then of course, there were all the questions about whether anyone unknown had given us any items to carry (of course not, I know all these people on the PSN-L whom I have never met face-to-face and who have sent me these strange boxes better than I know my mother). Anyway, everything arrived safely, and shortly before I left Dominica when I explained to Wayne that he could use your pieces to build a Lehman to monitor teleseisms, he got enthusiastic about that project. Though the groundmotion theshhold detector you sent Wayne was described to me in Dominica, I never actually saw it because it and Jody & I were never quite in the same place at the same time as we made our respective journeys around the island, though I understand it is at residence at Andre'&Joyce's, which is a shaking kind of place. Anyway, I have a couple of items from Dominica* to give to you and Lee Ann (maybe Chipper might also like them?), and I am planning to ride my bicycle over to your home (I need the exercise after not being able to ride on Dominica because the roads were just as crazy for the naive American as I was told they would be by Wayne and Clem) this weekend and drop them off. What would be a good time for you? -Edward * I also have a couple of things for others who contributed equipment but I am not planning to ride my bicycle to Texas and California. meredith lamb wrote: > Hi Edward, > > Have box for Wayne in Dominica ready for pickup. We maybe in > and out over the next few days....maybe if I leave it out front just > in case, we miss meeting? Hope you remember address here.... > 715 S. Pecos St. Denver, Co. ph 303-936-6221 > > or......we can deliver to your place? > > Thanks, Meredith, Lee Ann and Chipper the dog. > > -- > Meredith Lamb > <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><> > > Main Web site: http://www.users.uswest.net/~psnseismograph52/Index.html > > <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><> -- 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 From: Edward Cranswick Subject: Re: Baffled Date: Fri, 08 Jan 1999 00:22:31 -0700 Wayne- Four seconds of first motion of the seismogram you sent me 990101j.dm[1-3] is shown in the plot below (using my old VECTOR prog ram): ftp://groundmotion.cr.usgs.gov/PSN/Dominica/01jan1999/FIRSTMOT.GIF All three components are plotted at the same amplitude scale. Note that the Z- (Ch1) and N- (Ch2) components are similar and th at their first arrivals precede that of the E-component (Ch3) by 0.10-0.15 s but then the E is much larger and more impulsive. All the c omponents are very monochromatic, and you can see from the WinQuake FFT that the spectra peak at 4-6 Hz. In short, this is another weird seismogram, and I am not sure what is P & S and what is what (are all the channels connected 1, 2, 3? ... a rude question but I had to ask) . It maybe something idiosynchratically volcanic, but I am not very familiar with those seismograms. Have you recorded anything as simple as that first event on 27 Dec, i.e., large P on Z followed by large S on N&E? If you have, please send it to me. You should be able to use SDR as a voltmeter. Take a sinusoidal signal, e.g., Delores tapping the Z-component of the L-22 and i nput that directly into Ch1 of the SDR. Take the same signal in parallel and input it into the amplifier and then take the amplifier outp ut and input that into Ch2 of the SDR. Calculate the amplification by dividing the digital counts of Ch2 by those of Ch1. By controlli ng how hard she taps, Delores should be able to produce a signal that is on-scale in both straight and amplified versions. Save both record s and send them to me, and I will calculate the overall response of the amplifier using spectral ratios. -Edward Wayne Abraham J73WA wrote: > Ed, > > I will take up the direction finding subject with you again later because I am definitely going to have to use it alot and I want to > understand it properly. > > Larry told me how to change the frequency from 10 to 20hz which I did today. I also increased the sampling rate to 100. The m inute I > changed the frequency, my trace seemed to become at least 5 times wider than it was. I guess I will now have to reduce my gai n some > more. I have asked Larry how I can use my multimeter to know my gain. If he replies tomorrow, I will to back to Roseau to get it done. > > Seismic activity seems to have subsided somewhat. That's good because I want to be well calibrated when it decides to return. > > Take care, > > Wayne -- 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 From: "Al Allworth" Subject: Test Date: Sun, 10 Jan 1999 00:40:11 -0800 Real quiet for 2 days. ____________________________________ Al Allworth allworth@.............. Gold Beach On The Beautiful Southern Oregon Coast ____________________________________ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Bob Fryer Subject: Re: Test Date: Sun, 10 Jan 1999 01:07:01 -0800 Hi Al, Yeh, real quiet. I got dumped from another list the other day. Bob -- in the dripping PNW (Beaverton, OR) >Real quiet for 2 days. >____________________________________ > >Al Allworth allworth@.............. > >Gold Beach > >On The Beautiful Southern Oregon Coast > >____________________________________ ----- earthquake WARNING research ----- --- animals, people, scientific evidence --- --- http://www.teleport.com/~bfryer --- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "anthony p. giunta" Subject: event in New England Date: Sun, 10 Jan 1999 18:23:49 -0500 @ 5:52 am quake measuring 2.7, epicenter was located at Merrimac, Massachusetts A. P. Giunta Norwood, Mass _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: New WinQuake beta release Date: Sun, 10 Jan 1999 17:22:32 -0800 Hi Everyone, Happy New Year. In the last few months I have been working on a new Winquake (WQ) release. With some help from Arie Verveer (thanks Arie!) I think I have a stable beta release ready.I sent Arie a pre-beta release so he could checkout one of the new features in this release. I used the code he wrote to convert GSE2.0 files to the PSN format to allow WQ to view event files in that format. He ended up finding a few major bugs that where not happening on my system. Heres what's new in this release (Version 2.5.7 Beta): Mapping and Event Location: This is the main new feature in this release. After opening one or more event files and picking the P and S phase, a map can be drawn showing the stations with a distance circle. This can be used, if you have good P and S picks, to locate the event. To open a map window, click on the new map tool bar icon next to the RST (Reset) icon or use the "View/Locate Event" menu item. After opening a map window, you use the Zoom menu to zoom in and out. To move the globe around, double click on a point on the globe. This will move the map so that this point is now centered in the window. I still need to add some tool bar icon controls and come up with a better way of moving the map around. GSE2.0 support: WinQuake uses the keyword "BEGIN GSE2.0" to see if a file is in the GSE2.0 format. This keyword must be within the first 512 bytes of the file. WQ supports both single and multiple seismograms in one GSE2.0 file. If there is more than one seismogram in a file, it will be treated the same way as a PEPP or SEED volume data set. IASP91 travel time model: The option, controlled by the Travel Time Table and Display Phase control dialog boxes, uses the IASP91 travel time tables instead of the JB tables. There isn't much difference between the two sets of tables except that the IASP91 P and S tables go past the 107 degree point. Apparently they use some other first arrival P and S phases once the main P and S go into the earth's core shadow. Too enable this option, the file IASPI91.DAT must be in the WQ root directory. New Event Window Look: The Event Window now is divided into two sections using a splitter window. The text or header information is displayed in one window and the seismogram is displayed in another. Using the Options menu items you can control the colors and font of each window. You can download the new beta release at ftp://ftp.drnet.com/users/psn/software/wqbeta257.zip. If you are having problems with that link, the FTP server is hanging sometimes, you can download the file at ftp://ftp.seismicnet.com/software/wqbeta257.zip. The file is about 1.3 meg bytes in size. The zip file only contains a new winqk32.exe and some new and old data files. To use this release you must have an older version of WQ installed. After unzipping the beta release file in a temp directory copy all of the files to your main WQ root directory. You might want to rename the exciting winqk32.exe file before you do the copy. Note: The beta release is only for Windows 95/98 or NT. I won't be supporting the 16 bit version any more. Also, since this is a beta release the program will time out at the end on April. That's it. Let me know if you find any problems, have any suggestions or need any help with the new features in this beta release. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Wayne Abraham J73WA Subject: Re: New WinQuake beta release Date: Sun, 10 Jan 1999 23:42:00 -0400 Larry Will I lose my registration when the program times out in April? Wayne _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Re: New WinQuake beta release Date: Sun, 10 Jan 1999 21:07:46 -0800 At 11:42 PM 1/10/99 -0400, Wayne wrote: >Larry > >Will I lose my registration when the program times out in April? > >Wayne No... -Larry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: VBB transducer sensitvity Date: Mon, 11 Jan 1999 00:59:20 -0600 (CST) For those interested in the displacement detector used for the triple-feedback broadband seismometer: An update on the VRDT used for the STM-8 VBB seismometer: THE Conclusion: experiments indicate that configuring it per pervious specifications may make it TOO sensitive. I have re-evaluated the oscillator frequency question and gathered this information, some of which has been previously noted: a: The inductance of the VRDT when made with the TL021 transformer with the vane centered in a 2mm gap is 125 millihenries (per side). This calculates to an impedance of 3.9k ohms at 5khz, and 470 ohms at 600 hz. This would be the effective bridge impedance. b: With the borrowed digital LCR meter, I measured the inductance change as the vane is moved with the micrometer. Of course one side increases as the other decreases, so the changes need to be summed. They average 70 micro-henry per micron. This is a change of the reactance of each side of the bridge of 2.26 ohms per micron at 5 khz, and 0.27 ohms per side at 600 hz. Clearly the 5 khz (or even higher?) frequency gives much more sensitivity. c: The 600 hz option is used for the tiltmeters because it greatly reduces reactive changes caused by temperature, etc, of the long (over 10 meters) cables that are used. For the seismometer, the bridge can be within a few cm of the VRDT, so this is much less a problem. (Also, the tiltmeters are electrolytic resistive bridges, whose output was not frequency dependent.) As long as the bridge excitation is a clean sine wave, without high frequency harmonics, reactive changes should be minimized. d: SO... It seemed that the sine frequency should be 5 khz for maximum sensitivity. This makes the bridge impedance 4.02k ohms (at 1%), which is what it was designed for, and how I have drawn the schematic. BUT.... THis makes the transducer so sensitive that it is almost impossible to calibrate. (I actually changed one oscillator to 10khz for an application to a geophone, then studied the noise with the TL021 coils.) e: SO... It seems that for the present the 600 hz frequency is preferred. With the output of the oscillator at the transformer set to 350mv RMS, or 1 volt p-p referred to common, the transducer output is about 120 mv/micron. THe sensitivity does scale with the drive level. This sensitivity can be very roughly checked by turning the 30-turn, 100 ohm zero potentiometer in successive 1-turn steps. Since the transducer net reactance change is 0.5 ohms/micron at 600 hz, 3 ohms will represent 6 microns, or 720mv. (The "calibration" resistors and switch will produce the same result if they are installed.) So with the differential micrometer calibration, which is really only useful at 5 or 10 micron steps, the +,- 7 volt working range is spanned in 10 or 20 steps, which limits the statistics of the direct VRDT calibration. With the displacement gain amplifier at 20X, which is needed for the very high value of "r" in the feedback system, a level of 2400 mv/micron requires calibration by much higher resolution devices. However, its output is an indication of the system noise, which is about 1 mv p-p from 10 hz to DC. This is an equilavent ground noise of about 0.4 nanometers. I have recently operated the STM broadband vertical with a r value as high as 2 000 000 V/m. This extends the frequency response to above 100 hz. And of the differential capacitor Cp is reduced for a shorter natural period. like 50 seconds, the flat response level is very high, like 11 700 v/m/sec. It makes for very large 6-second microseisms. 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 From: "Francesco" Subject: R: New WinQuake beta release Date: Mon, 11 Jan 1999 12:19:20 +0100 Hello Larry, very good the new release of WQ! =20 One suggestions for the definitive version: the automatically save of = the files map in gif format . This option would be useful, because it = would simplify the job of conversion with clipboard and another graphic = programm. A question. New Winquake read automatically the GSE2.0 file? =20 Regards Francesco Nucera - I.E.S.N. PSN ITALY
Hello Larry,
very good the new release of = WQ! 
One=20 suggestions for the definitive version: the automatically save of the = files map=20 in  gif format . This option would be useful, because it would = simplify the=20 job of conversion with clipboard and another graphic = programm.
 
A question. New Winquake read=20 automatically  the GSE2.0 file? 
 
Regards
Francesco Nucera  - I.E.S.N. = PSN=20 ITALY
From: "Francesco" Subject: AutoDRM and GSE2.0 Date: Mon, 11 Jan 1999 12:23:23 +0100 Arie, wich is the system now, with the new beta release of Winquake, to read = the GSE2.0 file, via AutoDrm and e-mail request? Bye Francesco Nucera - I.E.S.N. - PSN ITALY
Arie,
wich is the system now, with the new = beta=20 release of Winquake, to read the GSE2.0  file, via AutoDrm and = e-mail=20 request?
 
Bye
Francesco Nucera   -  = I.E.S.N. -=20 PSN ITALY
From: Arie Verveer Subject: Re: AutoDRM and GSE2.0 Date: Mon, 11 Jan 1999 21:00:28 +0800 Hi Francesco, > wich is the system now, with the new beta release of Winquake, to read the GSE2.0 file, via > AutoDrm and e-mail request? You will still need to send your Email requests to your AutoDRM provider and save the returned data as a file. From then on I would use Larry's new release of Winquake. Its the complete package. The only thing you should be aware of , GSE2.0 files do contain checksum errors. They appear to be some sort of marker in the GSE2.0 file data. If you get a checksum error its better to decode the data via the "dos" program. It has some "fudge" code to ignore the checksum and extract the data that doesn't comply with the GSE2.0 standard. It only happens occasionally. I found using AutoDRM files in Winquake to be a grand way of locating epicentres. I used that feature today to locate a epicentre from a mine blast. All the best Arie. > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: robert barns <75612.2635@..............> Subject: MA 'quake Date: Mon, 11 Jan 1999 10:02:39 -0500 Hi gang, An item which might tickle the risibilities of you Californians-- = There was a 'quake yesterday near Merrimac, MA which registered 2.7 on t= he Richter scale! This made the CBS TV 11PM news in NYC. Any questions about what we do for excitement in this part to the worl= d? Bob Barns = = _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Bonnie Subject: 75612.2635@.............. Date: Mon, 11 Jan 1999 22:29:02 -0600 MA 'quake Hi, I can remember, when I was living in Oregon, that I thought that a 2 quake was a biggy! Then I moved to CA and got reedgucated real fast. Bonnie the crafty crafter Net-Tamer V 1.10 - Registered _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "anthony p. giunta" Subject: Re: 75612.2635@.............. Date: Tue, 12 Jan 1999 20:02:08 -0500 Well thats how it is in New England, Our observatory has quakes all of the time but not like your area...............Thanks Tony -----Original Message----- From: Bonnie To: psn-l@.............. Date: Tuesday, January 12, 1999 01:56 AM Subject: 75612.2635@.............. >MA 'quake > >Hi, I can remember, when I was living in Oregon, that I thought that a 2 >quake was a biggy! Then I moved to CA and got reedgucated real fast. > > >Bonnie >the crafty crafter > >Net-Tamer V 1.10 - Registered > > >_____________________________________________________________________ > >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 From: Arie Verveer Subject: Little quakes from distant BIG quakes Date: Wed, 13 Jan 1999 11:24:18 +0800 Hi, This may be a silly question but has anyone noticed that on some occasions a small local quake occurs very shortly after a big quake, even though the big quake has an epicenter many thousands of kilometers away ..? I have just posted a seismogram from the New Britain event (990112b.au1) that shows this. If you look at the low frequency recording of the event, nothing much appears. Typical with a local event. (990112b.au2) Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Arie Verveer Subject: Mb5.4 Talaud Island Indonesia Date: Wed, 13 Jan 1999 11:48:23 +0800 From: Arie Verveer Subject: Opps Date: Wed, 13 Jan 1999 12:50:57 +0800 Hi, Sorry about sending the an event to the PSN mailing list. Arie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: Little quakes from distant BIG quakes Date: Wed, 13 Jan 1999 17:48:56 -0700 (MST) On Wed, 13 Jan 1999, Arie Verveer wrote: > Hi, This may be a silly question but has anyone noticed that on some > occasions a small local quake occurs very shortly after a big quake, > even > though the big quake has an epicenter many thousands of kilometers away > .? Arie, A lot of people in the western US talk about earthquake triggering, and how waves from one event can alter the stress field just enough to start an event very far from away. Hence the triggered quake would happen in an area where the stress is very close to the strength of the fault; poised on edge I suppose. This case works very well for areas with a lot of small quakes (high b-value) like the Geysers, Yellowstone, or perhaps even Long Valley. This is a very interesting topic, but I don't think it is well accepted through out the seismology community. After all, the faulting process is not that well understood yet... If I remember correctly, quite a few USGS folks have been working on this very problem... ****************************************************************************** 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 From: John Taber Subject: Re: Little quakes from distant BIG quakes Date: Thu, 14 Jan 1999 15:47:46 +1300 (NZDT) Arie, You wrote: >This may be a silly question but has anyone noticed that on some >occasions a small local quake occurs very shortly after a big >quake, even though the big quake has an epicenter many thousands of >kilometers away? It doesn't sound like a silly question to me. There has been a lot of interest in the past few years in the possibility of large earthquakes triggering small earthquakes at a distance. The best example of this was the Landers earthquake in 1992. I don't know if anyone has found evidence of triggering thousands of km from a M6 eathquake, but it might be interesting to keep track of the number of times you see a small local earthquake just after a big distant earthquake, and compare this to the frequency of small local earthquakes. Cheers, John Taber _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Wayne Abraham J73WA Subject: CNSS Catalog Date: Thu, 14 Jan 1999 22:10:25 -0400 PSN Does anyone on this list know how to access the CNSS catalog using Winquake? This catalog seems to have quite a few quakes for the Caribbean region reported by the Puerto Rico station. Thanks, Wayne _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Bonnie Subject: taber@............. Date: Sat, 16 Jan 1999 21:59:30 -0600 Little quakes from distant BIG quakes Hi, I believe that there were two smaller quakes just before the 8.3 quake in 1857 at Fort Tajone. Sorry about the spelling. Bonnie the crafty crafter Net-Tamer V 1.11.2 - Registered _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Doug Crice Subject: Old seismograph Date: Mon, 18 Jan 1999 08:58:07 -0800 What is aledged to be an early, wind-up seismograph is for sale on e-bay.com at http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=56865800 So far, the price is reasonable, but I know nothing other than what is on the site and that the vendor seems well regarded by prior customers. You have 3 days until close of the auction. -- Doug Crice web site http://www.georadar.com GeoRadar Inc. e-mail dcrice@............ 19623 Via Escuela Drive phone 408-867-3792 Saratoga, CA 95070 USA fax 408-867-4900 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Robert Avakian Subject: Re: Old seismograph Date: Mon, 18 Jan 1999 11:34:06 -0800 Looks like a barograph from the photos. Notice the vents on the top and sides, I doubt a seismograph would have that. Bob Avakian Doug Crice wrote: > > What is aledged to be an early, wind-up seismograph is for sale on > e-bay.com at > > http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=56865800 > > So far, the price is reasonable, but I know nothing other than what is > on the site and that the vendor seems well regarded by prior customers. > You have 3 days until close of the auction. > -- > Doug Crice web site http://www.georadar.com > GeoRadar Inc. e-mail dcrice@............ > 19623 Via Escuela Drive phone 408-867-3792 > Saratoga, CA 95070 USA fax 408-867-4900 > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: ACole65464@....... Subject: Re: Old seismograph Date: Mon, 18 Jan 1999 22:25:08 EST The item that eBay is offering, to me, looks like a 30+ year old thermograph (recording thermometer). Any one else would like to take a guess? Allan Coleman, Edmonds, Wa. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: New Event? Date: Mon, 18 Jan 1999 21:03:45 -0800 Hi All Did anyone pick up an event around 15:53 UTC? I used Larry's new event locator (great addition) and it maybe in Central America or Alaska or maybe my machine acting up :-) Regards Barry. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: New Event Date: Mon, 18 Jan 1999 21:09:52 -0800 Opps I think the time would be 04:54:00 UTC Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Canie Brooks Subject: Re: New Event Date: Mon, 18 Jan 1999 21:15:45 -0800 At 09:09 PM 1/18/99 -0800, barry lotz wrote: >Opps > I think the time would be 04:54:00 UTC > Barry Take a look at this site: http://aslwww.cr.usgs.gov/Seismic_Data/heli2.htm Something happened! > > > >_____________________________________________________________________ > >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 From: Canie Brooks Subject: Re: New Event Date: Mon, 18 Jan 1999 21:15:45 -0800 At 09:09 PM 1/18/99 -0800, barry lotz wrote: >Opps > I think the time would be 04:54:00 UTC > Barry Take a look at this site: http://aslwww.cr.usgs.gov/Seismic_Data/heli2.htm Something happened! > > > >_____________________________________________________________________ > >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 From: "Dewayne (n0ssy) & Linda (n0uqf) Hill" Subject: New Event Date: Tue, 19 Jan 1999 05:18:00 +0000 Arival time in Westminster Co. (39.835n 105.062w) was 04:20:15 GMT. Dewayne (n0ssy) & Linda (n0uqf) Hill Westminster, Colorado USA 39.83569n 105.0627w Elev. 5660ft. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Dewayne (n0ssy) & Linda (n0uqf) Hill" Subject: RE: new event Date: Tue, 19 Jan 1999 05:48:47 +0000 Earlier reported 04:20:15 may be "S" wave, With "P" at 03:50:12 UTC. Dewayne (n0ssy) & Linda (n0uqf) Hill Westminster, Colorado USA 39.83569n 105.0627w Elev. 5660ft. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: New Event Date: Mon, 18 Jan 1999 21:53:37 -0800 Canie I like the link. Thanks. Regards Barry Canie Brooks wrote: > At 09:09 PM 1/18/99 -0800, barry lotz wrote: > >Opps > > I think the time would be 04:54:00 UTC > > Barry > > Take a look at this site: > http://aslwww.cr.usgs.gov/Seismic_Data/heli2.htm > > Something happened! > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Seisguy@....... Subject: Fwd: USGS Earthquake report Date: Tue, 19 Jan 1999 01:17:53 EST Magnitude 6.4 earthquake near NEW IRELAND REGION, P.N.G. 4.36S, 153.16E depth 114.3km Tue Jan 19 03:35:33 1999 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 Tue Jan 19 03:35:33 1999 (EST Mon Jan 18 22:35:33 1999) (PST Mon Jan 18 19:35:33 1999) Magnitude: 6.4, determined using its surface wave characteristics Epicenter: 4.36S, 153.16E (NEW IRELAND REGION, P.N.G.) Precision: B, where A is fine and D is coarse. Depth of focus: 114.3km 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 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: Karl Cunningham Subject: UPS's Date: Tue, 19 Jan 1999 10:05:47 -0800 Hi all -- I noticed that CompUSA (in Southern California, at least) has a 300 watt Uninterruptable Power Supply on sale for $80 this week. This could make a relatively inexpensive backup power supply for home-made seismometers. The ad doesn't say how long it will provide that amount of power. As a reference, my seismometer electronics and computer running SDR consume about 40 watts without the monitor. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Angel Rodriguez Subject: Re: UPS's Date: Tue, 19 Jan 1999 14:04:17 -0500 Hi All, I use a 325 VA UPS much like the one Karl mentions and it worked well for about 30 minutes (no monitor). Then I would begin to see the base levels of the traces begin to drop. I opened up the UPS box and took out the 12 volt 5 amp/hr battery an replaced it with a regular car battery. I could probably go for a few days now. Angel At 10:05 AM 01/19/1999 -0800, you wrote: >Hi all -- > >I noticed that CompUSA (in Southern California, at least) has a 300 watt >Uninterruptable Power Supply on sale for $80 this week. This could make a >relatively inexpensive backup power supply for home-made seismometers. The >ad doesn't say how long it will provide that amount of power. > >As a reference, my seismometer electronics and computer running SDR consume >about 40 watts without the monitor. > > >Karl Cunningham >La Mesa, CA. >PSN station #40 >karlc@....... > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Wayne Abraham J73WA Subject: Re: UPS's Date: Tue, 19 Jan 1999 18:16:03 -0400 Angel I could kiss you for this idea. I have a 1200VA UPS sitting around with a bad battery. We have frequent power outages down here and sometimes it goes for hours. NAPA, here I come. Wayne Angel Rodriguez wrote: > Hi All, > > I use a 325 VA UPS much like the one Karl mentions and it worked well for > about 30 minutes (no monitor). Then I would begin to see the base levels of > the traces begin to drop. I opened up the UPS box and took out the 12 volt > 5 amp/hr battery an replaced it with a regular car battery. I could > probably go for a few days now. > > Angel _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: JIm Hannon Subject: Re: UPS's Date: Tue, 19 Jan 1999 17:12:55 -0600 Wayne Abraham J73WA wrote: > Angel > > I could kiss you for this idea. I have a 1200VA UPS sitting around with a bad > battery. We have frequent power outages down here and sometimes it goes for > hours. NAPA, here I come. > > Wayne > > Angel Rodriguez wrote: > > > Hi All, > > > > I use a 325 VA UPS much like the one Karl mentions and it worked well for > > about 30 minutes (no monitor). Then I would begin to see the base levels of > > the traces begin to drop. I opened up the UPS box and took out the 12 volt > > 5 amp/hr battery an replaced it with a regular car battery. I could > > probably go for a few days now. > > > > Angel > > __ If you can get it I would reccomend a deep discharge rated battery like a trolling motor (marine) battery rather than a car battery. You will get a longer useful life from a battery constructed for deep discharge. We are getting a Trace Engineering inverter and 24 volts worth deep discharge batteries here, to back up the power to run my heating system. Things get a little tense when the power goes out at -20 F. -- 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 From: "Mark Robinson" Subject: Re: UPS's Date: Wed, 20 Jan 1999 12:16:57 +1300 HI folks, In general I would recommend the use of true sinewave inverters for seismo applications. THe square wave Pulse Width Modulated ones generate a ton of hash which is likely to cause intereference to the sensitive electronics. UPSs are generally designed to work with the smaller battery. Connecting a larger one may take you beyond the duty cycle the device was designed for. Bolt some more metal to the switching transistor heatsinks or add a fan. have fun Mark G Robinson | ZL2TOD | other@............... Box 8770, Auckland 1035, New Zealand Phone +64-9-846-3296 | Fax +64-9-849-7408 ------------------------------------------------ 20 Jan 1936 King George V of England died. 20 Jan 1953 Eisenhower sworn in as 34th U.S. President. 20 Jan 1991 Soviet Black Beret Police storm Latvian Interior Ministry building. ----- Original Message ----- From: Karl Cunningham To: Sent: Wednesday, 20 January 1999 07:05 Subject: UPS's >Hi all -- > >I noticed that CompUSA (in Southern California, at least) has a 300 watt >Uninterruptable Power Supply on sale for $80 this week. This could make a >relatively inexpensive backup power supply for home-made seismometers. The >ad doesn't say how long it will provide that amount of power. > >As a reference, my seismometer electronics and computer running SDR consume >about 40 watts without the monitor. > > >Karl Cunningham >La Mesa, CA. >PSN station #40 >karlc@....... > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: USGS Geologic Division Subject: USGS Earthquake report Date: Tue, 19 Jan 1999 22:20:01 -0600 Magnitude 6.4 earthquake near NEW IRELAND REGION, P.N.G. 4.36S, 153.16E depth 114.3km Tue Jan 19 03:35:33 1999 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 Tue Jan 19 03:35:33 1999 (EST Mon Jan 18 22:35:33 1999) (PST Mon Jan 18 19:35:33 1999) Magnitude: 6.4, determined using its surface wave characteristics Epicenter: 4.36S, 153.16E (NEW IRELAND REGION, P.N.G.) Precision: B, where A is fine and D is coarse. Depth of focus: 114.3km 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 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 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: UPS info Date: Wed, 20 Jan 1999 01:18:33 -0600 (CST) Some comments about increasing the support capacity of UPS systems: This is generally feasible; the actual power capacity (watts or VA) is fixed by the inverter, but the time it can support a load can be extended considerably by adding external batteries. All the batteries MUST be of the same type, capacity, manufacturer, date, etc, for them to parallel properly, which usually means discarding the original internal small gell-cell battery. But if the original battery was 5 ampere-hours, using a 50 or 100 AH marine battery will require 10 to 20 times longer to recharge, which might mean several days after an extended AC outage, since the charger in switched UPS systems is usually quite small, like about 5% of the full load current. Always use fuses when connecting batteries in parallel, preferably the low-voltage "rectifier" or DC type fuses. If a cell shorts in one battery in parallel with another, the short will dissipate all the energy of the paralleled batteries. Here is some previously posted information: We operate several types of UPS systems at the seismic observatory and at the major remote sites. Some have the 1 killowatt "Best" brand units, which are switched systems: the inverter is switched on and connected to the load only when the AC line fails, like most computer UPS boxes. For these, we parallel the internal battery (ies) with external batteries, using low voltage, low resistance "rectifier" fuses for protection. The large DC battery connectors are helpful (Grainger 6A070 series, about $10). It is VERY important that all the batteries that are connected in parallel be of exactly the same type and age, even if this means replacing the original internal battery with a new one, or simply omitting it. We use the 90 amp-hr Delco photo- voltaic batteries, or else the deep-discharge "marine" type batteries connected in a 48 volt, 200 ampere-hour configuration. With continuous float charging and periodic equalize cycles, they still only last 3 to 4 years. We have also made some hybrid UPS systems using commercial 1kw precision inverters (by TOPAZ), large 3-phase DC supplies (13.6V at 250 amps), and large "stationary" batteries by Exide. These are 660 amp/hr cells with high calcium plates, which are used in stationary service like telephone exchanges and backup power for mine hoists. They are guaranteed for 20 years. With 660 Ah cells, we get about 6 hours of UPS power at the 1kw level. (We can get the generator going by then). (Also, we limit our loads to about 750 watts). Our loads operate continuously from these inverters, so the AC-DC supply has to provide its input (like 100 Amps) plus re-charge the batteries in a resonable time. It is also precise enough to be set within 10 millivolts to properly float the batteries. So with the batteries always connected to the inverter, there is no power transfer needed when the AC goes out. However, we do have a "failsafe" arrangement that connects the external loads to the AC line in the rare event that the inverter fails. We also have a pair of digital timers that force an "equalizing" charge voltage for several hours once a month by switching on a different resistor in the AC-DC supply voltage feedback reference. These large systems weigh about 1500 lbs. 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 From: John Taber Subject: re: Little quakes from distant BIG quakes Date: Thu, 21 Jan 1999 16:22:33 +1300 (NZDT) Bonnie wrote: > > Hi, I believe that there were two smaller quakes just before the 8.3 > quake in 1857 at Fort Tajone. Sorry about the spelling. I'm not familiar with what happened before the Fort Tejon earthquake, but it sounds like you might be describing foreshocks. Though the definition is a bit arbitrary, a foreshock is usually defined as being near and perhaps on the same fault as the mainshock, whereas in the case of distant triggering, the earthquakes may be on completely different fault systems. Nearby earthquakes do seem to trigger each other. Once an earthquake has occurred, the odds of another earthquake of the same or larger magnitude are higher than if the first quake hadn't happened. The trick is to figure out which earthquakes are foreshocks, and there has been a lot of debate as to how or if that is possible. Cheers, John _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: re: Little quakes from distant BIG quakes Date: Wed, 20 Jan 1999 21:13:42 -0700 (MST) On Thu, 21 Jan 1999, John Taber wrote: > Nearby earthquakes do seem to trigger each other. Once an > earthquake has occurred, the odds of another earthquake of the > same or larger magnitude are higher than if the first quake hadn't > happened. The trick is to figure out which earthquakes are > foreshocks, and there has been a lot of debate as to how or if > that is possible. Indeed, some even claim that a period of low seismic activity preceeds major earthquakes, but if you plot, for example, the time of earthquake occurrences as a function of the distance along the San Andreas fault (within a certain distance) you will see many blank spots which are not followed by large quakes, and only a few that are... Recent attempts by Chinese seismologists based on foreshocks to predict large quakes were attempted, but a recent group sent over to China to evaluate their method seems to think that their method is not as good as they say it is. Another thing to consider is that different portions of different faults behave quite differently. Consider Landers, which has the most peculiar aftershock distributions (decaying sinusoidal activity)... ****************************************************************************** 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 From: Bonnie Subject: taber@............. Date: Wed, 20 Jan 1999 20:40:04 -0600 Little quakes from distant BIG quakes Hi John, Thanks so much for writing. Foreshocks and aftershocks are indeed interesting. I have always wondered how far in advance a quake must strike (a smaller one before a big one) before it can be called a foreshock to a larger event. Also, how long do aftershocks go on after the main event has occurred? I guess I am full of questions. Thanks. Bonnie the crafty crafter Net-Tamer V 1.11.2 - Registered _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Roger Griggs Subject: Re: UPS's Date: Wed, 20 Jan 1999 22:14:29 -0800 At 06:16 PM 1/19/99 -0400, you wrote: >I could kiss you for this idea. I have a 1200VA UPS sitting around with a bad >battery. We have frequent power outages down here and sometimes it goes for >hours. NAPA, here I come. > >Wayne Wayne, Would your UPS happen to be a APCC 1200VX? If it is, we have several of these old units still in operation in our Electric Transmission control centers. I have replaced the batteries many times in the past few years. A great source for replacement batteries is AMP KING BATTERY Co. in San Francisco. The 1200VA unit takes two Powersonic PS-12180 18 amp hour batteries. Last year we picked up a dozen or so for $58 apiece. Be sure to obtain a Maintenance Manual for your particular unit so that it can be re-calibrated with the new batteries. You have to reset and test the drop out voltage levels, output freq and output voltage. I have seen these shift over time. As far as using car batteries for a UPS, I would be quite hesitant. Car batteries are not made for UPS service. You need sealed lead acid, deep cycle types. And definetly put fuses between paralled units. You cannot believe the damage a shorted battery can cause not to mention the deadly acid that can be sprayed in all directions if they blow. Roger _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Finke, John E." Subject: RE: taber@............. Date: Thu, 21 Jan 1999 13:58:08 -0500 I'm sure that the number of aftershocks and time following the larger event vary for each event based on several seismological factors. In the central United States, however, four extreme events occurred in late 1811 to 1812 that triggered aftershocks ranging from several hundred to a couple thousand over a period of several months to several years depending on which author you read. Again this is an extreme case. At least one of these earthquakes is believed to be the largest ever in the United States followed by the 1964 Alaskan earthquake. > -----Original Message----- > From: Bonnie [SMTP:bschafer@.......... > Sent: Wednesday, January 20, 1999 8:40 PM > To: psn-l@.............. > Subject: taber@............. > > Little quakes from distant BIG quakes > > Hi John, > > Thanks so much for writing. > > Foreshocks and aftershocks are indeed interesting. I have always > wondered how far in advance a quake must strike (a smaller one before a > big one) before it can be called a foreshock to a larger event. Also, > how long do aftershocks go on after the main event has occurred? > > I guess I am full of questions. Thanks. > > > Bonnie > the crafty crafter > > Net-Tamer V 1.11.2 - Registered > > > _____________________________________________________________________ > > 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 From: S-T Morrissey Subject: horizontal VBBs Date: Thu, 21 Jan 1999 13:38:36 -0600 (CST) Barry, Regarding your question about making a horizontal VBB sensor: The transfer function will work for any configuration of the mass movement: there is nothing in it that "knows" what the direction of the restoring force is, either vertical or horizontal. Just as the vertical only needs to know what the mechanical period is, so does a horizontal configuration. And if the period is reasonably long, the damping term will be mostly controlled by the proportional feedback resistor, which is why commercial VBB sensors are calibrated at a condition of "indifferent" equilibrium, or very long period. Also, it is worth noting that the triple VBB feedback will work quite well with the Lehman or S-G horizontal pendulums if they are equipped with a proper displacement transducer and feedback coil. This is one sure way to obtain a defined and calibrated response from these instruments. I have recently done some work on the feedback schematics to simplify things. One improvement is to eliminate the instrumentaion amplifier used for the integrator: a single low-pass filter on the quad amplifier circuit card works fine. THis card has a terminal strip that allows for mounting the feedback components as well as the high-pass output capacitors. THis allows an external multi-pole switch to select the feedback components for any effective period, which includes a "1-second" period for adjusting the seis or zeroing it without having to wait out a long integration time. For this, the feedback capacitor C is NOT changed, since this changes the output signal level in the flat portion of the response curve; (the output is the value of k = 1/(G*C), where G = Gn/M, Gn being the feedback coil constant, M is the mass; the units DO work out to Volts*seconds/meter). I will try to post the revised schematics tomorrow. 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 From: Bonnie Subject: Finke@........... Date: Thu, 21 Jan 1999 21:24:06 -0600 taber@............. Hi, thank you so much for writing and answering my questions. I really appreciate it. Bonnie the crafty crafter Net-Tamer V 1.11.2 - Registered _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: taber@............. Date: Thu, 21 Jan 1999 23:55:44 -0700 (MST) On Wed, 20 Jan 1999, Bonnie wrote: > Foreshocks and aftershocks are indeed interesting. I have always > wondered how far in advance a quake must strike (a smaller one before a > big one) before it can be called a foreshock to a larger event. Also, > how long do aftershocks go on after the main event has occurred? > I guess I am full of questions. Thanks. > Bonnie > the crafty crafter Bonnie, The definition of an aftershock or foreshock is arbitrary. Usually researchers will define the events in terms of: A) The distance from the mainshock (usually less than 50 km) B) The time from the main shock (any where from seconds to several years) Aftershocks are usually given a wider range than foreshocks, at least that I have seen. Aftershocks have been suggested to follow a decay rule called Omori's Law, however most aftershocks do not fit this model, nor can aftershock seqences be characterized according to parameters given in the model. Omori's Law only works for certain special areas. Other areas are very strange in terms of the aftershock sequence... ****************************************************************************** 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 From: "Dan" Subject: Re: UPS info Date: Fri, 22 Jan 1999 10:06:02 -0800 You can get a longer battery life, if you use the batteries in series, I.e.. 6 and 6 for 12 or individual cells 2 volt 300 amp each for 12 , In a series config you will have more plate surface area, spreading out the amperage taken per plate and giving a lot longer discharge time giving , cost is less than finding a matched pair , only need to find same voltage and amp hour out. If you use in parallel, the specific gravity and internal resistance of each batt must be matched . not the case with series batt, look for a battery supply house in your area, and buy one made for solar use 6 volt 380 amp hour is about 180 dollars each Dan swanson -----Original Message----- From: S-T Morrissey To: psn-l@............. Date: Tuesday, January 19, 1999 23:19 Subject: UPS info > >Some comments about increasing the support capacity of UPS systems: >This is generally feasible; the actual power capacity (watts or VA) >is fixed by the inverter, but the time it can support a load can >be extended considerably by adding external batteries. All the >batteries MUST be of the same type, capacity, manufacturer, date, etc, >for them to parallel properly, which usually means discarding the >original internal small gell-cell battery. But if the original battery >was 5 ampere-hours, using a 50 or 100 AH marine battery will require >10 to 20 times longer to recharge, which might mean several days after >an extended AC outage, since the charger in switched UPS systems is usually >quite small, like about 5% of the full load current. > >Always use fuses when connecting batteries in parallel, preferably the >low-voltage "rectifier" or DC type fuses. If a cell shorts in one battery >in parallel with another, the short will dissipate all the energy of >the paralleled batteries. > >Here is some previously posted information: > >We operate several types of UPS systems at the seismic observatory and at >the major remote sites. Some have the 1 killowatt "Best" brand units, >which are switched systems: the inverter is switched on and connected >to the load only when the AC line fails, like most computer UPS boxes. >For these, we parallel the internal battery (ies) with external batteries, >using low voltage, low resistance "rectifier" fuses for protection. >The large DC battery connectors are helpful (Grainger 6A070 series, >about $10). It is VERY important that all the batteries that are >connected in parallel be of exactly the same type and age, even >if this means replacing the original internal battery with a new >one, or simply omitting it. We use the 90 amp-hr Delco photo- >voltaic batteries, or else the deep-discharge "marine" type >batteries connected in a 48 volt, 200 ampere-hour configuration. >With continuous float charging and periodic equalize cycles, >they still only last 3 to 4 years. > >We have also made some hybrid UPS systems using commercial 1kw precision >inverters (by TOPAZ), large 3-phase DC supplies (13.6V at 250 amps), and >large "stationary" batteries by Exide. These are 660 amp/hr cells >with high calcium plates, which are used in stationary service like >telephone exchanges and backup power for mine hoists. They are >guaranteed for 20 years. With 660 Ah cells, we get about 6 hours >of UPS power at the 1kw level. (We can get the generator going by then). >(Also, we limit our loads to about 750 watts). > >Our loads operate continuously from these inverters, so the AC-DC >supply has to provide its input (like 100 Amps) plus re-charge the >batteries in a resonable time. It is also precise enough to be set >within 10 millivolts to properly float the batteries. So with the >batteries always connected to the inverter, there is no power >transfer needed when the AC goes out. However, we do have a >"failsafe" arrangement that connects the external loads to the >AC line in the rare event that the inverter fails. We also have >a pair of digital timers that force an "equalizing" charge voltage >for several hours once a month by switching on a different resistor >in the AC-DC supply voltage feedback reference. These large >systems weigh about 1500 lbs. > >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) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Bonnie Subject: hernlund@....... Date: Fri, 22 Jan 1999 23:43:04 -0600 taber@............. Hi John, Thank you so much for patiently answering my questions. I only have one more--honest! bbg What makes a fault that has lain dormant for many years suddenly come to life? I am thinking of the fault responsibile for the '71 quake. It really didn't do too much up until that time in fact I heard that geologists were very surprised at its' sudden activity. Thanks again. Bonnie the crafty crafter Net-Tamer V 1.11.2 - Registered _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: UPS info Date: Sat, 23 Jan 1999 09:09:10 -0800 Dan et al Speaking of solar-- I have been wondering about solar charging for my system. Does one have the same problem with matching solar cells in parallel as with batteries? Do they have to be matched? I'm not sure how they are rated, by volts or power or current. I assume applying a back voltage on a cell will not hurt but, will only the higher voltage cell be working at any one time? ie will the current be close to double for parallel connection? Barry Dan wrote: > You can get a longer battery life, if you use the batteries in series, > I.e.. 6 and 6 for 12 or individual cells 2 volt 300 amp each for 12 , In > a series config you will have more plate surface area, spreading out the > amperage taken per plate and giving a lot longer discharge time giving , > cost is less than finding a matched pair , only need to find same voltage > and amp hour out. If you use in parallel, the specific gravity and > internal resistance of each batt must be matched . not the case with series > batt, > look for a battery supply house in your area, and buy one made for solar > use 6 volt 380 amp hour is about 180 dollars each > Dan swanson _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Greg Subject: Re: UPS info Date: Sat, 23 Jan 1999 11:30:44 -0700 barry lotz wrote: > > Dan et al > Speaking of solar-- I have been wondering about solar charging for my > system. Does one have the same problem with matching solar cells in parallel as > with batteries? Do they have to be matched? Don't know. > I'm not sure how they are rated, by volts or power or current. Watts. > ie will the current be close to double for parallel connection? I think so. I wish I could afford to install a bunch of solar cells, but they're pretty expensive. I found a site with a reasonable attitude about them. http://www.windsun.com/ They're one of the few sites with actual prices and information. Kyocera and Siemens also have web sites with information about their panels. Just found this quote by accident: "In this diagram, the two diodes at the END are the blocking diodes, which prevent reverse current flow at night. These are seldom needed in systems with controllers, as nearly all charge controllers have a built in method of preventing reverse current." I also had a bookmark to another site where a guy powered his Icom 706-II with a solar cell and a battery charger. The neat thing was that it was portable and there was no AC involved. In other words no expensive inverters. ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: solar panel info Date: Sat, 23 Jan 1999 13:57:28 -0600 (CST) Barry, Some info on solar panels: The mid-day sun shines at mid-lattitudes at about 1 killowatt per square meter. SO a solar panel with 10% efficiency (a quality panel), can produce 100 watts from a large 3 ft x 4 ft panel. More affordable panels, made from "amorphous" rather than crystaline cells, are about half as efficient, but cost as little as 1/5 the cost. Panels used for satellites can approach 20% efficiency. Recently an innovation to "recycle" the portions of cyrstaline silicone ingots that are unsuitable for semiconductor production may help bring down the cost of the more efficient cells. Panels are usually rated for power output in watts, with a 20 watt SOLAREX panel being about 24" x 30". The internal cell connections are set up for a nominal "12 volt" output by proper series and parallel connections to produce up to 2 amperes (for the 20 w panel). The actual output voltage will range above 18 volts, so a voltage regulator is needed for long term charging of batteries, and it must provide protection from reverse current from the battery into the panel. A MAJOR problem arises when large panels are connected in parallel because of the fact that when no light is shining on a portion of the panel (due to leaves or shadows or nightfall, etc), the cells become un-polarized and act as low value resistors that effectively short out part of the panel, so a fully illuminated parallel connected panel can cause a damaging reverse current in the shadowed panel. So low loss (Schottky) diodes are used in series with each panel when they are connected in parallel. Make sure that the battery has a fuse to protect things if the regulator and/or diodes fail (or the operator makes a stupid connection). Another risk with large panels is when they are connected in series for "line voltage" or 120 volt battery/inverter power systems. The voltage can suddenly go from nil to lethal if a cloud moves away, so the panel circuitry must always be considered as "live and dangerous". For sizing a panel for a given load, we have found that a 20-watt panel, charging a 90 ampere-hour 12 volt deep-discharge or photo-voltaic battery (float charged at 13.6 v), can provide reliable continuous operation of a seismic telemetry station drawing a load of 0.1 amperes (at 13.6 volts). But near the winter solstice or minimum of the length of the day, it barely makes it, especially if snow covers the panel for more than a day. This latter problem can be reduced by mounting the panel almost vertically, which we do in Alaska, where we need to get the most from the low sun angles in winter. OF course, as the battery ages, the support time shortens; the useful life of a good sealed battery is about 3 to 4 years. A common maintenance problem in some areas is with large birds roosting on the panels and dumping droppings on them. We remedy this with a "bird bar", which is an aluminum angle mounted across the top of the panel with stainless steel nails driven through it so that they point upward in a row that the birds will not roost on. In some areas, we have had problems with people target shooting at the panels. We try to minimize the damage by providing a 3/4" treated plywood cover on the back of the solar panel; it can actually be fit inside the aluminum frame of the SOLAREX panel. This can cause excessive heating of the panel, so ventilation holes must be provided along the bottom and top of the wood cover. I have not priced panels recently; the 20 watt SOLAREX cost $180 several years ago. 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 From: Karl Cunningham Subject: Re: UPS info Date: Sat, 23 Jan 1999 12:13:27 -0800 Barry -- Solar panels are for the most part constant-current devices, with the current being more or less proportional to the incoming solar flux. The ratings go something like 12 volts at 2.4 amps. The voltage is a nominal voltage, and the current is (for reputable companies) rated assuming 1000 watts/meter^2 of incoming solar flux. You can expect to get this amount of flux at noon in mid latitudes on a bright clear day. A panel with a nominal 12-volt rating will put out approximately the same current over a range from zero to about 19 volts, where it starts to drop off. The peak POWER output is at about 19 volts. When you connect them directly to a 12-volt battery, there will be a constant current going into the battery so you need some voltage limit to avoid overcharging the battery. A good (fairly fast) way to recharge a lead-acid battery (liquid or gel electrolyte) is to charge at constant current up to a certain voltage, then change to constant voltage for "float." This float voltage is what the battery can tolerate for extended periods of time. The voltage levels depend on the chemistry of the particular battery involved. This charging scheme is well suited to solar charging since all you need to do is sense the high-rate voltage threshold and introduce a voltage limiter to keep from overcharging the battery. You should have a diode between the solar panel and the battery to prevent reverse current flow for night time or clouds. Solar panels are available through surplus outlets for $4 per watt, somtimes much less. The early ones had a lifetime of about 20 years out in the sun so be careful of those. Before you buy, take the panel out in the sun and measure its open-circuit voltage and short-circuit current. Surplus panels sometimes have open or shorted cells. Shorted ones are no problem, but if there are any open ones, you will have to jumper them to use the panel. In either case you'll get less output. Hope this helps, Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... At 09:09 AM 1/23/99 -0800, you wrote: > Dan et al > Speaking of solar-- I have been wondering about solar charging for my >system. Does one have the same problem with matching solar cells in parallel as >with batteries? Do they have to be matched? I'm not sure how they are rated, by >volts or power or current. I assume applying a back voltage on a cell will not >hurt but, will only the higher voltage cell be working at any one time? ie will >the current be close to double for parallel connection? > >Barry > >Dan wrote: > >> You can get a longer battery life, if you use the batteries in series, >> I.e.. 6 and 6 for 12 or individual cells 2 volt 300 amp each for 12 , In >> a series config you will have more plate surface area, spreading out the >> amperage taken per plate and giving a lot longer discharge time giving , >> cost is less than finding a matched pair , only need to find same voltage >> and amp hour out. If you use in parallel, the specific gravity and >> internal resistance of each batt must be matched . not the case with series >> batt, >> look for a battery supply house in your area, and buy one made for solar >> use 6 volt 380 amp hour is about 180 dollars each >> Dan swanson > > >_____________________________________________________________________ > >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 From: "Dan" Subject: Re: UPS info Date: Sat, 23 Jan 1999 12:57:06 -0800 >barry lotz wrote: >> >> Dan et al >> Speaking of solar-- I have been wondering about solar charging for my >> system. Does one have the same problem with matching solar cells in parallel as >> with batteries? Do they have to be matched? > >Don't know. No, to match a solar cell, you only need to have max watt out same, as voltage and current will vary with amount of light, does no even have to be same brand >> I'm not sure how they are rated, by volts or power or current. >Watts. Yes, the watts given for a cell are based on full sun light, at high noon. The max energey deliverd by sun is 1000 watts per square meter. In califorina, your usable light is 4 to 5 hours per day for solar calcuting purposes, This is why you need to have so many. If you use the modules l with battery , the module rated for 17 volts will put out less than its rated output , when used with batterys the working voltage will be betwween 12 and 15 . Example a 50 watt module working at 13.0 volts will produce only 39 watts. >> ie will the current be close to double for parallel connection? If both cell share the same amount of light at the same time it should be close >I think so. >I wish I could afford to install a bunch of solar cells, but they're >pretty expensive .. They are not cheap, about 300.00 for 50 watts. I live in san francisco, out in the by the beach, So I chose to use wind power, A new model, thats whisper quite, mounted 3 feet above my roof. puts out 12 or 24 volt- 500 watt at 28mph, I use to in parrell to get 200 watts at 9mph, which is over most of day and night. the cost is 12 or 24 volt 500 watt for <400.00 I found a site with a reasonable attitude about them. >http://www.windsun.com/ >They're one of the few sites with actual prices and information. when you buy modules, make sure they have diodes between each cell in module, as this will keep the module producing power, when a cloud go over head or leaves lands on module blocking light on a cell. Without doides the cell will stop output, and if you have more than one panel in parell or series it will start distchharge into blocked one. >Kyocera and Siemens also have web sites with information about their >panels. > >Just found this quote by accident: >"In this diagram, the two diodes at the END are the blocking diodes, >which prevent reverse current flow at night. These are seldom needed in>systems with controllers, as nearly all charge controllers have a built >in method of preventing reverse current." > blocking diodes are used to prevent clouds blocking one module and and causing a discharge from other modules, some hook ups put 2 or 3 moduels in series or parrell before the controller come into play. because of voltage drop in each connect to controller .. >I also had a bookmark to another site where a guy powered his Icom >706-II with a solar cell and a battery charger. The neat thing was that >it was portable and there was no AC involved. In other words no >expensive inverters. you can get small panels rated for 15.6volt 11 watt 7 to 800 ma for about 120 or less good for handi talki. for 706 you would need to figure how long of transmit time will be needed, and recive current . I am not sure what the curent on a 706 is, 100 watt output? Dan >,Greg > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: solar cells Date: Sat, 23 Jan 1999 13:07:35 -0800 Greg,Sean Thomas & Karl Thanks for the info. I have been running a homemade solar charging circuit that I got from a back issue of Nuts&Volts when they had a solar power series of articles. I will add some more panels with low drop diodes. I have been using Horowitz & Hill's recommendations on battery charging. Where I live, there are alot of trees and therefore the sun is periodic. I ran a controller once that kept track of power and time over a 24hr period and one 12"x12" panel was not enough to keep up with 5vts@...... It is an inexpensive panel. I forget what the rated wattage is. With multiple panels I can orientate them to get more current as the sun chifts position. There is a company back east that sells a 386 SBC that runs @ 0.1 watt. I hope to incorporate this in a field unit. I would use a 8 bit processor but some of the math on my data acquisition program (digital filter & FFT) run much slower on an 8 bit unit. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Dan" Subject: Fw: UPS info correction Date: Sat, 23 Jan 1999 09:40:08 -0800 Please disregard my last message about ups info, in trying to answer my many email in a short amount of time, I make drafts first before sending, then I go back later and edit or just delete. In this case, my email program has the file button just above the send button about 1/8". On my laptop I used the buitl in stick mouse and and my thumb hit the right mouse pad, and away it went. I need to find either a better way, or put a stop send switch on modem line to stop send. Thanks dan _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Dan" Subject: Re: UPS info Date: Sat, 23 Jan 1999 15:28:36 -0800 I do not know anymore, who is taking to who. The messages I received and sent, are not what I see coming back. The original and questions are not same nor my answer to them I should probably stay out of this one Dan -----Original Message----- From: Karl Cunningham To: PSN-L Mailing List Date: Saturday, January 23, 1999 12:14 Subject: Re: UPS info >Barry -- > >Solar panels are for the most part constant-current devices, with the >current being more or less proportional to the incoming solar flux. The >ratings go something like 12 volts at 2.4 amps. The voltage is a nominal >voltage, and the current is (for reputable companies) rated assuming 1000 >watts/meter^2 of incoming solar flux. You can expect to get this amount of >flux at noon in mid latitudes on a bright clear day. > >A panel with a nominal 12-volt rating will put out approximately the same >current over a range from zero to about 19 volts, where it starts to drop >off. The peak POWER output is at about 19 volts. When you connect them >directly to a 12-volt battery, there will be a constant current going into >the battery so you need some voltage limit to avoid overcharging the battery. > >A good (fairly fast) way to recharge a lead-acid battery (liquid or gel >electrolyte) is to charge at constant current up to a certain voltage, then >change to constant voltage for "float." This float voltage is what the >battery can tolerate for extended periods of time. The voltage levels >depend on the chemistry of the particular battery involved. This charging >scheme is well suited to solar charging since all you need to do is sense >the high-rate voltage threshold and introduce a voltage limiter to keep >from overcharging the battery. > >You should have a diode between the solar panel and the battery to prevent >reverse current flow for night time or clouds. > >Solar panels are available through surplus outlets for $4 per watt, >somtimes much less. The early ones had a lifetime of about 20 years out in >the sun so be careful of those. Before you buy, take the panel out in the >sun and measure its open-circuit voltage and short-circuit current. >Surplus panels sometimes have open or shorted cells. Shorted ones are no >problem, but if there are any open ones, you will have to jumper them to >use the panel. In either case you'll get less output. > >Hope this helps, > >Karl Cunningham >La Mesa, CA. >PSN Station #40 >karlc@....... > > >At 09:09 AM 1/23/99 -0800, you wrote: >> Dan et al >> Speaking of solar-- I have been wondering about solar charging for my >>system. Does one have the same problem with matching solar cells in >parallel as >>with batteries? Do they have to be matched? I'm not sure how they are >rated, by >>volts or power or current. I assume applying a back voltage on a cell will >not >>hurt but, will only the higher voltage cell be working at any one time? ie >will >>the current be close to double for parallel connection? >> >>Barry >> >>Dan wrote: >> >>> You can get a longer battery life, if you use the batteries in series, >>> I.e.. 6 and 6 for 12 or individual cells 2 volt 300 amp each for 12 , In >>> a series config you will have more plate surface area, spreading out the >>> amperage taken per plate and giving a lot longer discharge time giving , >>> cost is less than finding a matched pair , only need to find same voltage >>> and amp hour out. If you use in parallel, the specific gravity and >>> internal resistance of each batt must be matched . not the case with >series >>> batt, >>> look for a battery supply house in your area, and buy one made for solar >>> use 6 volt 380 amp hour is about 180 dollars each >>> Dan swanson >> >> >>_____________________________________________________________________ >> >>Public Seismic Network Mailing List (PSN-L) >> >>To leave this list email listserver@.............. with the body of the >>message: leave PSN-L >> >> > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: hernlund@....... Date: Sun, 24 Jan 1999 00:15:53 -0700 (MST) On Fri, 22 Jan 1999, Bonnie wrote: > What makes a fault that has lain dormant for many years suddenly come to > life? I am thinking of the fault responsibile for the '71 quake. It > really didn't do too much up until that time in fact I heard that > geologists were very surprised at its' sudden activity. Bonnie, Really, all anyone can say about that is the fault moves when the stresses in the material containing the fault exceeds the frictional strength of the fault itself. The stress is not constant, because other activity in the same region changes the balance of forces constantly. Also, not all activity along a fault results in earthquakes. At times, the fault moves very slowly (creep) and other times the material along the fault is deforming by folding up into low hills or troughs. Also, water may get into the fault and make it more slippery. Different rock types along different portions of the fault provide different frictional resistance to slipping. With all of the complexities surrounding faults almost any kind of behavior can occur. Usually, there are theoretical limits as to how strong the fault can be and how long it would take for the movement of the plates to accumulate enough stress to cause an earthquake. But accurate measurements on non-earthquake processes that help remove stress are only being applied in several locations, so we don't really always know how it works on other areas. Add to the complexity the probability that these complex processes surrounding the fault are always changing and cannot usually be well studied by paleoseismic methods to aid in forecasting because by the time we figured out how the fault worked at one point in time it probably has changed... So when you hear that geologists were surprised over some occurrence in seismology, then you shouldn't be surprised that they are surprised... :-) Scientists have to sell their progress to institutions and bureaucrats in order to have money that funds their research. So it is hard to know if what you hear in the press is the whole truth. This is why peer-reviewed science is so important. This is the preferred medium for letting people know about your research because each submission is reviewed by other scientists who are usually jealous or fame-hungry themselves. Therefore they are quite critical, and you can believe that what you are reading in an accepted journal in a particular field is the most representative idea of what is going on in areas of science. Some institutions (including one in CA whose name I won't mention) hold big press conferences and babble an awful lot after each quake. The popular press puts out really awful stories based on these conferences because the articles are not peer-reviewed. Persons who criticize this behavior could be called jealous themselves I suppose. Science is such a human event! Anyhow, if you have any further questions Bonnie, you may want to e-mail me directly at hernlund@....... instead of posting to the PSN-L mailing list. Some people on the list might not like to see their e-mail cluttered up too much with stuff about which they are already familiar... ****************************************************************************** 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 From: John Taber Subject: Re: foreshocks and quiet faults Date: Mon, 25 Jan 1999 13:00:36 +1300 (NZDT) Bonnie wrote: > Foreshocks and aftershocks are indeed interesting. I have always > wondered how far in advance a quake must strike (a smaller one before a > big one) before it can be called a foreshock to a larger event. Also, > how long do aftershocks go on after the main event has occurred? > As John and John have said, foreshocks are arbitrarily defined as some relatively short time (I think usually less than a few months) before the main shock, but it is possible to relate swarms of small earthquakes to larger earthquakes that happen years later. A seismologist here (Frank Evison) has been testing a hypothesis that a group of earthquakes that are clustered in space and time can be used to predict a larger earthquake several years later. For example a group of 10 earthquakes with a maximum magnitude of around 4 were used to forecast a M7 earthquake 4 years later. The method is still being tested and it can't predict the exact time, but can give a general idea of when a big earthquake is likely. >What makes a fault that has lain dormant for many years suddenly come to >life? A fault can be considered to be "active" even though it hasn't moved in a few thousand years. A volcano may be dormant in that there has been no magma recently moving to the surface, but stresses are building up continuously on "quiet" faults. The two sides of the fault may be stuck together, but the rocks nearby are being compressed or stretched just like a rubber ball. This deformation can be measured by GPS receivers. I think it is fairly common for major faults to have essentially no small earthquakes for much of the time between major earthquakes. For example in New Zealand, the 2 faults that are of the greatest concern (the Wellington Fault and the Alpine Fault) appear to have no earthquake activity at the moment. John Taber _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: [Fwd: Leased-line digital communications information needed] Date: Sun, 24 Jan 1999 22:43:19 -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". To CNSS technical types: I am looking to review the technology being used for telemetry of digital data over voice-grade continuous circuits such as leased phone lines, hard-wire, or microwave circuits. We are currently using some Motorola modems for 9 remote seismic stations and need to get more but want to make sure we know about all possiblities and use the most effective available. Anyone with information about such things, please send it to me and I will make a summary of it to post on the CNSS WEB pages for the use by all. FYI our current most demanding use is: telemetry of 6 seismic channels of 4-byte samples at 100 samples per second which is about 24 Kbaud rate (though very compressible since at least one of every four bytes is always the same). We are currently using: Motorola V.3400 model modems in 2wire and 4wire leased line modes. These have been costing about $350 for used-refurbished units per modem. These modems are rated at V.34 33.6 with compression and error checking but no retransmission. We use them with DCE speed of 28,800 baud and a DTE speed of 38,400 baud. All error checking and compression is handled by the modems. They have been fairly reliable but seem particularly sensitive to line level changes and sometimes drop off-line for no obvious reason and must be power cycled at one end to bring them back on line. Steve Malone E-mail: steve@...................... Geophysics Program Phone: (206) 685-3811 University of Washington FAX: (206)543-0489 Box 351650 Office: ATG-226 Seattle, WA 98195 http://www.geophys.washington.edu From: KACAMACHO@....... Subject: Re: foreshocks and quiet faults Date: Mon, 25 Jan 1999 10:46:43 EST I WOULD LIKE TO THANK YOU GENTLEMEN FOR TAKING TIME OUT TO INFORM US "LAY PEOPLE" WHO DO NOT HAVE THE EXTENT OF KNOWLEDGE BUT ARE VERY CURIOUS. EVEN THOUGH BONNIE ASKES ELEMENTAL QUESTIONS, AT LEAST SHE ASKS. THANKS AGAIN. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Filter IC's Date: Mon, 25 Jan 1999 18:38:23 -0800 For what it's worth Maxim has a new line of lowpass ic's with low power as well. Both 5 pole (1.2ma) and 8 pole(2ma). There is a little offset, so a DC block would be needed before gain amps. Looks interesting. They're the MAX7400 series. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: pictures (fwd) Date: Mon, 25 Jan 1999 21:30:58 -0700 (MST) ---------- Forwarded message ---------- Date: Mon, 25 Jan 1999 21:52:03 -0500 From: olde english tudor inn To: hernlund@....... Subject: pictures To whom it may concern: Hi, I am doing a science fair Project for my school and I was wondering if anyone had any pictures of a seismograph that I could get a copy of or that someone could send me over E-Mail. If anyone can help just drop me a line by E-Mail: tudorinn@.............. ! Thanks, AAP _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Wayne Abraham J73WA Subject: Website Date: Tue, 26 Jan 1999 01:34:59 -0400 PSN I am pleased to inform you of the new Dominica Public Seismic Network website. Ever since I came to you guys seeking information and help in setting up a Public Seismic Network on Dominica, you have been more than accomodating. Thank you all of you. Our new site is still under construction as I am still throwing 1001 ideas in my mind. It will continue undergoing changes until I am satisfied with the final product (which I doubt very much). Take a peek at http://www.freeyellow.com/members6/dominicapsn/ Your feedback will be appreciated. Wayne. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Greg Subject: Re: Website Date: Mon, 25 Jan 1999 23:00:07 -0700 Wayne Abraham J73WA wrote: > Your feedback will be appreciated. Very very nice. Makes me want to work on my site. ;) ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Angel Rodriguez Subject: Re: pictures (fwd) Date: Tue, 26 Jan 1999 09:05:48 -0500 John, I have several pictures of my homemade stuff you can see them at=20 http://www.barriles.com/seismo/bru.html I hope they help some. I will be here today all day but then I have to go to Seattle for a meeting, I=B4m on the board of directors of REI, but I will be back in Panama on the 3rd of feb. I also have some of my local quakes including yesterdays Colombia quake on my ftp at=20 ftp://ftp.barriles.com Thanks, Angel At 09:30 PM 01/25/1999 -0700, you wrote: >---------- Forwarded message ---------- >Date: Mon, 25 Jan 1999 21:52:03 -0500 >From: olde english tudor inn >To: hernlund@....... >Subject: pictures > >To whom it may concern: =20 > Hi, I am doing a science fair Project for my school and I was >wondering if anyone had any pictures of a seismograph that I could get a >copy of or that someone could send me over E-Mail. If anyone can help >just drop me a line by E-Mail: tudorinn@.............. ! Thanks, > > AAP > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the=20 >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Norman Davis WB6SHI Subject: Re: foreshocks and quiet faults Date: Tue, 26 Jan 1999 07:11:42 -0800 Just a note. You might want to get into lower case. When your type upper case it means you are shouting. At 10:46 AM 1/25/99 EST, you wrote: >I WOULD LIKE TO THANK YOU GENTLEMEN FOR TAKING TIME OUT TO INFORM US "LAY >PEOPLE" WHO DO NOT HAVE THE EXTENT OF KNOWLEDGE BUT ARE VERY CURIOUS. EVEN >THOUGH BONNIE ASKES ELEMENTAL QUESTIONS, AT LEAST SHE ASKS. THANKS AGAIN. > >_____________________________________________________________________ > >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 From: "David A. Nelson" Subject: large aleutian event Date: Thu, 28 Jan 1999 22:59:56 +1300 jst recorded (08:30 UTC 28 Jan 99) Fox Islands, aleutian islands region Mb6.5 recorded well by tony in hawaii and myself ohhh and by the way come the 14 April i will no longer be living in NZ i am shifting to just south of Madison, Wisconsin after a stop in hawaii for ~6 days to meet my girlfriend, see tony, and play in the lava etc my girlfriend and i will fly to LA have ~3 days in the LA area maybe get a chance to meet a couple of the guys before we drive through to wisconsin over the next 4 days We will be in LA from approx 19 - 22 April Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://www.seismicnet.com/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 From: John Hernlund Subject: Re: large aleutian event Date: Thu, 28 Jan 1999 09:14:48 -0700 (MST) On Thu, 28 Jan 1999, David A. Nelson wrote: > after a stop in hawaii for ~6 days to meet my girlfriend, see tony, and > play in the lava etc my girlfriend and i will fly to LA have ~3 days in the > LA area maybe get a chance to meet a couple of the guys before we drive > through to wisconsin over the next 4 days > We will be in LA from approx 19 - 22 April > Dave Dave, If you are passing through Phoenix, let me know and I can show you around ASU if you want... ****************************************************************************** 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 From: Edward Cranswick Subject: Re: large aleutian event Date: Thu, 28 Jan 1999 18:55:24 -0700 Dave- And without asking why you are moving from NZ to Wisconsin, you should stop by and see us (Mark Meremonte, John Lahr, Meredith Lamb, me and the NEIC) on your road trip from LA to there. Please let us know what's happening. -Edward "David A. Nelson" wrote: > jst recorded (08:30 UTC 28 Jan 99) Fox Islands, aleutian islands region > Mb6.5 recorded well by tony in hawaii and myself > > ohhh and by the way come the 14 April i will no longer be living in NZ > > i am shifting to just south of Madison, Wisconsin > > after a stop in hawaii for ~6 days to meet my girlfriend, see tony, and > play in the lava etc my girlfriend and i will fly to LA have ~3 days in the > LA area maybe get a chance to meet a couple of the guys before we drive > through to wisconsin over the next 4 days > We will be in LA from approx 19 - 22 April > > Dave > Co-ordinator: > New Zealand > Public Seismic Network > Dave A. Nelson ZL4TBN > 24 Jensen St., > Green Is., Dunedin, > South Is.. New Zealand. > > http://www.seismicnet.com/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) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Fred Subject: Anyone else get that Date: Sat, 30 Jan 1999 23:43:17 -0800 Did anyone else catch the quake in Columbia. I haven't seen any threads about it ? -- How much choice did God have in constructing the Universe? If the no boundary proposal is correct, he had no freedom at all to choose initial conditions. He would have only had the freedom to choose the laws the universe obeyed. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "David A. Nelson" Subject: Re: Anyone else get that Date: Sun, 31 Jan 1999 22:54:11 +1300 At 23:43 30/01/99 -0800, you wrote: >Did anyone else catch the quake in Columbia. I haven't seen any threads >about it ? > Fred there have been plenty of event files posted for it i didn record some surface waves from it here in NZ but it wasnt worth posting for me a good # of others got excellent records Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://www.seismicnet.com/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 From: "David A. Nelson" Subject: Dominica station now on map Date: Mon, 1 Feb 1999 20:41:20 +1300 greetings all, the Dominica station is now on the world map and in the database sorry wayne for taking so long things have been in an upheaval around this place :)) thanks for ur patience Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://www.seismicnet.com/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 From: John Hernlund Subject: Rough Draft of Seismograph Theory Page Date: Mon, 01 Feb 1999 20:24:10 -0700 (MST) Hello Everyone, Because of many requests for information and general questions about seismographs from people on the internet and in my community I have decided to undertake a project that describes the way seismometers work both mathematically and graphically. This is because I can never find a good book to refer people to that ties all the concepts together. I have only covered material pertaining to simple damped seismometers, but I plan to add more material as I go eventually describing some of the mathematics of various filters, the sampling process, Fourier Analysis, and other usually advanced and scattered topics. It is only a rough draft now, but I thought the PSN would be the perfect place to ask for a review and suggestions on what has been completed thus far. If you get the chance, read through it, and e-mail me any comments/suggestions that you have. Be honest: if it sucks and doesn't make any sense at all, then let me know because you won't be the first to feel that way! ****************************************************************************** John Hernlund E-mail: 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 From: John Hernlund Subject: Oops, here is the address... Date: Mon, 01 Feb 1999 20:25:22 -0700 (MST) I forgot to include the address previously! Here it is: http://www.public.asu.edu/~hernlund/seismograph/ ****************************************************************************** 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 From: "David A. Nelson" Subject: MAJ QUAKE In progress Date: Wed, 3 Feb 1999 15:05:23 +1300 0145 UTC 03 feb Maj quake in progress looks to be in sth pacific possib fiji region and M6.5 or greater Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://www.seismicnet.com/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 From: meredith lamb Subject: Re: MAJ QUAKE In progress Date: Tue, 02 Feb 1999 19:27:35 -0700 "David A. Nelson" wrote: > 0145 UTC 03 feb Maj quake in progress > > looks to be in sth pacific possib fiji region > > and M6.5 or greater > > Dave > Co-ordinator: > New Zealand > Public Seismic Network > Mainly just getting L waves in Denver....but possible aftershocks?? Meredith Lamb _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: MAJ QUAKE In progress Date: Tue, 02 Feb 1999 19:31:19 -0800 Dave: From Red Puma- 03Feb1999 01:13:59.3 20.2S 174.2W 33 mb=5.9 A NEI TONGA ISLANDS Barry David A. Nelson wrote: > 0145 UTC 03 feb Maj quake in progress > > looks to be in sth pacific possib fiji region > > and M6.5 or greater > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "David A. Nelson" Subject: Ms6.2 ?????????? Date: Wed, 3 Feb 1999 17:11:45 +1300 NEIC 99/02/03 01:13:57 20.20S 174.36W 33.0 6.2Ms TONGA ISLANDS wowwowo thats gotta be understated, That would make it the higest amplitude Ms6.2 I would have ever seen then hahaha my winquake whis is usually pretty close to most recent teleseisms, it is saying Ms6.7 and John H. u made similar comments in ur mail will be really interested to see the Mw for this one Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://www.seismicnet.com/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 From: "David A. Nelson" Subject: tongan event Date: Wed, 3 Feb 1999 18:27:55 +1300 im gonna have to eat humble pie, as i hang my head in shame :) my winquake shows Ms6.2 when P and S are correctly located but at least its still showing reasonable calibration Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://www.seismicnet.com/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 From: Larry Cochrane Subject: New WinQuake beta release version 2.5.8 Date: Tue, 02 Feb 1999 21:58:42 -0800 Hi Everyone, Today I released a new beta version of WinQuake. This is beta version 2.5.8. I made a few changes from the last release so heres what's new. New Command Line option: Currently WinQuake (WQ) can print a file from the command line. The format is: winqk32 /p file_name I added the ability to create a gif image of the event file. The format is winqk32 /g input_file [output_file_or_dir]. The output file or directory is optional. If this argument is not supplied, WQ will us the input file name and append ".gif" too it and use this as the output name. It will show up in the same directory as the input file. If you only supply a directory, for the output, WQ will save the gif image file in the directory specified and use the input file name + gif. If you specify a file name and directory, WQ will use that as the output name and location. Local Data Directory: Under the File menu items you will see a new menu item called Local Data Directory... This is used when WQ is run on a network/file server setup. If the WQ exe is located on a server you can specify a local directory on the system that is running the program. Some of the data / config files (ending in *.dat) should be located on the local system rather then the server system. The email.dat, phase.dat and replay.dat files should all be located on the local system. The other data and bin files should remain on the server system. If you are not running WQ on a server, this directory should be pointing to the location of the winqk32.exe file. Common to all Windows: You can now print the Event, FFT or Event Location Map windows in color. In the File menu item you will see a new menu item called Print Settings. You can turn color printing on or off using the Color menu item. If selected, the colors used for printing will be the same ones selected for the event/fft/map windows except the background color. This can be different from the window background color to save ink. Event Window: I made a major change to how WQ displays the data in memory. Before WQ would read in the data from an event file into a 16 bit array. This is fine for the current PSN format since it only has 16 bit numbers. The problem was when WQ read in another format (SEED, PEPP, SAC etc) that had bigger numbers than +- 32000 counts, it needed to divide the data down so that it would fit into the 16 bit array. WQ now reads and displays the data in a 32 bit array. Since WQ no longer needs to divide the data as it reads it in, I removed the SEED/SAC/PEPP Control dialog box (under the Options menu) that was used to control the divide number. There still is a problem when saving one of the other formats as a PSN file do to the number size difference. What I did is add a compression / divide number in the Save dialog box. If data compression is needed, a edit box will be accessible to change / override the number WQ calculates for you. I added a DC-Offset check box to the Save dialog box. Before WQ would always apply the DC offset used for centering the seismogram around zero. You can now turn this "feature" off if needed. The Save dialog box now has a new save type option. A while back I came up with some code that converted a PSN binary event file into an ASCII text file. I added this code to WQ, so you can now save any event file as text data file. Since the data numbers are not limited to a 16 bit output array, like the PSN binary version, there is no need to divide the data. Unfortunately I have not added the code to read in this format. I moved the event file start / end time correction dialog box to the Modify dialog box. This was one of the File menu items. I fixed a problem with saving the integrated data. Before, if you integrated the data and tried to save it, WQ would always save the non-integrated array (WQ keeps two arrays, one for the normal data and other if the integration feature is used). Now if you are viewing the integrated data and open the Save dialog box, the integrated data will be saved. FFT Window. I added a few new features to the FFT window. I now display the frequency and the period (1/f) of the mouse location when its somewhere in the FFT window. You can now zoom in and display one decade of frequencies. You can use the mouse to zoom in/out by double clicking or use the menu or tool bar. You can now save the FFT window as a GIF image. Event Location Map Window: I now display the event location, if known, on the left side of the window. I made it so that you can see the distance circles update as you move the P and S markers on one of the event windows. So if you open up a map window and arrange the windows so you can see both the map and the event windows, and move the P or S marker around, you should see the distance circle move for that station. You can now save the map as an GIF image and print the map window. I think that's it... I have created two zip files and placed them on two system. One zip file, wq258b_exe.zip (~300k) only contains a new exe file. If you downloaded the earlier beta release all you need to do is download this one. The other file wq258b_full.zip (~1.2meg) contains all of the files needed to run this release. Here are the links: ftp://ftp.drnet.com/users/psn/software/wq258b_exe.zip and ftp://ftp.drnet.com/users/psn/software/wq258b_full.zip or ftp://ftp.seismicnet.com/software/wq258b_exe.zip and ftp://ftp.seismicnet.com/software/wq258b_full.zip Please let me know if you run into any problems running this release. I'm going too try and NOT add any more features so I can stabilize what I have and make a more formal release. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: New WinQuake beta release version 2.5.8 Date: Wed, 03 Feb 1999 01:18:14 -0700 (MST) Larry, Winquake has really become some outstanding software for the PC. I have a few options you could add to really confuse people, but also make it better: -Multiple component display -Particle Motion Plot (2d is easiest) -Addition and subtraction, multiplication and division of seismograms. -Rotation of data into transverse, radial components. -Multiplication of FFT data: eg. multiplying the inverse of the frequency response for a seismometer with the seismogram to amplify weak portions of the spectrum. There are a few items this would need like a definite low frequency cutoff to prevent instability... ****************************************************************************** John Hernlund E-mail: 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 From: Greg Subject: Re: New WinQuake beta release version 2.5.8 Date: Wed, 03 Feb 1999 12:15:32 -0700 Larry Cochrane wrote: > Today I released a new beta version of WinQuake. This is beta version > 2.5.8. I made a few changes from the last release so heres what's new. > > New Command Line option: > Currently WinQuake (WQ) can print a file from the command line. The format is: > winqk32 /p file_name I added the ability to create a gif image of the > event file. The format is winqk32 /g input_file [output_file_or_dir]. The I bet that's handy for the new event files section of your web site. Also someone could set up their own NT server web site with it. Legally? I have no use personally. Hey maybe someday. You never know. It is possible. In theory anyways. ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: question - Scream program? Date: Wed, 03 Feb 1999 14:08:57 -0800 I got this message today from Rex Dickens. I told him that I don't know anything about this program and that I would forward his message to the PSN-L list. If you can help please email him directly. Thanks, -Larry Cochrane >From: Rex0110@....... >Date: Wed, 3 Feb 1999 15:57:55 EST >To: cochrane@.............. >Subject: question >X-Mailer: AOL 3.0 16-bit for Windows sub 86 > > Let me first say I don't know if this message will aply to you. If not >could you please tell me where to go or who to ask to get my question >answered. > > For a school research project I am researching seismic waves and >earthquakes. We are using a program called SCREAM! version 2.1 We need the >system requirements for this program. For now it is on a tempary computer, >but we will be moving it to a different one. We are connected with PSN, we >got the software from Indiana University, Bloomington, IN and don't have the >requirements. > > If you need more information either email me or the teacher incharge >John Portle (jportle@.......... >Bloomington High School North >Bloomington Indiana > Thank you for your time. >Rex Dickens > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Northern California double event Date: Wed, 03 Feb 1999 18:43:36 -0800 Hi Everyone, Today (2/03) at 16:19 PST (00:19 UTC 02/04) we had two events back to back. This is from the USGS finger service. 99/02/04 00:19:36 37.16N 121.55W 6.3 3.8Ml A* 6 mi ENE of Morgan Hill, CA 99/02/04 00:21:41 37.16N 121.55W 6.5 3.7Ml A* 6 mi ENE of Morgan Hill, CA The first event shook the computer table a little, but I did not feel it. Both events where recorded on scale with my Lehman (my SG sensor is off line). The FBA23A strong motion sensor I have also picked up both events. The first event produced a max g of around 13 mg. The second event produced ~5 mg. I have a new channel online, LC4. It is the E-W component of the FBA23A sensor. I have not been recording this channel because of a problem with the sensor. Through Edward Cranswick, Kinemetrics fixed and re calibrated the sensor. I also changed the gain the of FBA Z channel. It was set to +-1 g max (+-32768 A/D counts), it is now set to +-2 g's like the other components. I have updated my station information web page at http://www.seismicnet.com/stations.html with more information about the FBA channels. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: bzimmerman@............ Subject: Re: question - Scream program? Date: Thu, 04 Feb 1999 08:26:49 -0500 (EST) Scream is from Guralp systems. Try their Web page for more info: http://www.guralp.demon.co.uk/ Brian Zimmerman On Wed, 3 Feb 1999, Larry Cochrane wrote: > I got this message today from Rex Dickens. I told him that I don't know > anything about this program and that I would forward his message to the > PSN-L list. If you can help please email him directly. > > Thanks, > > -Larry Cochrane > > >From: Rex0110@....... > >Date: Wed, 3 Feb 1999 15:57:55 EST > >To: cochrane@.............. > >Subject: question > >X-Mailer: AOL 3.0 16-bit for Windows sub 86 > > > > Let me first say I don't know if this message will aply to you. If not > >could you please tell me where to go or who to ask to get my question > >answered. > > > > For a school research project I am researching seismic waves and > >earthquakes. We are using a program called SCREAM! version 2.1 We need the > >system requirements for this program. For now it is on a tempary computer, > >but we will be moving it to a different one. We are connected with PSN, we > >got the software from Indiana University, Bloomington, IN and don't have the > >requirements. > > > > If you need more information either email me or the teacher incharge > >John Portle (jportle@.......... > >Bloomington High School North > >Bloomington Indiana > > Thank you for your time. > >Rex Dickens > > > > _____________________________________________________________________ > > 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 From: Edward Cranswick Subject: Re: question - Scream program? Date: Thu, 04 Feb 1999 10:21:41 -0700 John- Steve Horton, Debi Kilb and Paul Bodin very effectively used the SCREAM system during our recent study of the 1998 Sep 25 Pymatuning Earthquake in Pennsylvania/Ohio. Their results from SCREAM are described on the at this website: -Edward Larry Cochrane wrote: > I got this message today from Rex Dickens. I told him that I don't know > anything about this program and that I would forward his message to the > PSN-L list. If you can help please email him directly. > > Thanks, > > -Larry Cochrane > > >From: Rex0110@....... > >Date: Wed, 3 Feb 1999 15:57:55 EST > >To: cochrane@.............. > >Subject: question > >X-Mailer: AOL 3.0 16-bit for Windows sub 86 > > > > Let me first say I don't know if this message will aply to you. If not > >could you please tell me where to go or who to ask to get my question > >answered. > > > > For a school research project I am researching seismic waves and > >earthquakes. We are using a program called SCREAM! version 2.1 We need the > >system requirements for this program. For now it is on a tempary computer, > >but we will be moving it to a different one. We are connected with PSN, we > >got the software from Indiana University, Bloomington, IN and don't have the > >requirements. > > > > If you need more information either email me or the teacher incharge > >John Portle (jportle@.......... > >Bloomington High School North > >Bloomington Indiana > > Thank you for your time. > >Rex Dickens > > > > _____________________________________________________________________ > > 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 From: John Taber Subject: Re: scream software Date: Fri, 5 Feb 1999 09:43:08 +1300 (NZDT) I've sent the following by email but I thought some people on the PSN list might be curious so I've copied my answer to the list. Rex, Larry Cochrane put your question about scream on the PSN mailing list. I'm guessing that the scream v2.1 program you refer to is one written by Guralp Systems (they make some of the PEPP seismographs). The information pages for the software can be found at http://www.guralp.demon.co.uk/software/scream/index.htm. From my limited understanding of the program (we tried out an earlier version) it is primarily a data aquisition program. Will you be using it to collect data from a seismometer or for analysing data collected elsewhere? Regards, John Taber John Taber School of Earth Sciences, Victoria University John.Taber@.............. Box, 600, Wellington, New Zealand phone: +64-4-472-1000 fax: +64-4-495-5186 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: PSN newspaper story Date: Thu, 04 Feb 1999 14:20:16 -0700 Kathleen- I just got the photocopy you sent me of your newspaper article for the Santa Cruz (CA) Sentinel (Saturday, 30 Jan, p. A2) about the Public Seismic Network (PSN) and Mark Halliday in Ben Lomond, CA, and I think the article is excellent! Perhaps, it could be scanned (I don't know what the copyright rules are), and Larry Cochrane could put it in area for newspaper articles, etc., on the RWC/PSN . -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 From: Edward Cranswick Subject: [Fwd: Morgan Hill doublet recorded from Ben Lomond] Date: Thu, 04 Feb 1999 14:42:32 -0700 -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". Mark- You recorded very nice records of the Morgan Hill doublet (990204a.mh1 & .mh2), except that the peak values of the first event exceeded your 12-bit A/D by about 50% full-scale. Up in the mountains, you have a wonderfully quiet recording site compared to those poor guys down in the mud and freeways of Silicon Valley. That's why the USGS put all the Calnet stations up in the hills, because nobody lives there and it's so quiet ... unfortunately it is in Silicon Valley where everyone lives that we also need to have recordings of earthquakes so we will know what effects, i.e., damage, may happen next time there is a large event. But I'd rather live in Ben Lomond, and it is good place to study seismic sources. -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". From: Larry Cochrane Subject: Re: New WinQuake beta release version 2.5.8 Date: Thu, 04 Feb 1999 17:10:07 -0800 At 01:18 AM 2/3/99 -0700, John Hernlund wrote: >Larry, > Winquake has really become some outstanding software for the PC. I have a >few options you could add to really confuse people, but also make it better: Thanks John. > >-Multiple component display Edward C. has also asked for this one. >-Particle Motion Plot (2d is easiest) >-Addition and subtraction, multiplication and division of seismograms. >-Rotation of data into transverse, radial components. >-Multiplication of FFT data: eg. multiplying the inverse of the frequency > response for a seismometer with the seismogram to amplify weak portions of > the spectrum. There are a few items this would need like a definite low > frequency cutoff to prevent instability... As I learn how to do these things, I'll add them... -Larry Cochrane _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: New WinQuake beta release version 2.5.8 Date: Thu, 04 Feb 1999 18:40:07 -0700 (MST) On Thu, 4 Feb 1999, Larry Cochrane wrote: > >-Particle Motion Plot (2d is easiest) Parametric plot from two files. It would just be a plot of the amplitude component from one channel vs. the amplitude data from another with both sharing the same time values. Of course different sampling rates would be a problem, but the faster channel could be re-sampled to the slower one... > >-Addition and subtraction, multiplication and division of seismograms. This might take a lot of memory. Perhaps the program could open two files and add the corresponding values one at a time (I do this with fortran usually) and then write the result to a new file. > >-Rotation of data into transverse, radial components. This is not too hard, it just sounds worse than it is. It is possible to rotate the data about any of three perpendicular axes using three very simple matrices for any angle. This is equivalent to finding the component of one channel onto a different coordinate system offset by definite angles... > >-Multiplication of FFT data: eg. multiplying the inverse of the frequency > > response for a seismometer with the seismogram to amplify weak portions of > > the spectrum. There are a few items this would need like a definite low > > frequency cutoff to prevent instability... This is more of an experimental thing. If the user records an input pulse to his/her seismograph and stores the FFT of this file, then the deconvolution of an earthquake file would consist in dividing the FFT for the event by the FFT for the impulse of the seismometer. Frequencies from the event below a certain level would have to be cut off (bandpassed) because some times trying to add information into a time series that was never there in the first place adds instability (weird results). > As I learn how to do these things, I'll add them... If there is any information or anything else I could do to help just let me know... ****************************************************************************** John Hernlund E-mail: 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 From: "Dennis W. Pope" Subject: Advice/Recommendations Date: Fri, 5 Feb 1999 07:02:06 -0500 I am looking for advice and recommendations as to what type of seismomete= r (vertical, horizontal, GS, Lehman, etc) I should install for amateur use = in my home. I would be like to keep the cost in the $2000 to $3000 range. I = am located in central Ohio. I want to acquire the data on a PC which I have and can dedicate for this use. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: Re: Advice/Recommendations Date: Sat, 6 Feb 1999 12:53:07 -0600 (CST) Dennis, The most interesting earthquake data comes from a broadband vertical sensor. The energy comming from an earthquake has strong components of the body (or direct) waves (P and S) that generally are of periods of one second or so, and the later surface waves can range from 20 to hundreds of seconds. So at St. Louis U, we have broadband pen-and ink monitor recorders (the classical helical drum format) of our more sensitive stations to allow us to keep up with global activity in real time; most of the actual data disappears into the computers for later analysis. The homemade sensors you ask about (Lehman, SG) are very primitive (my opinion) designs that don't even encompass modern concepts of seismometer design. They are also horizontal sensors so they respond poorly to the primary waves of distant (1000 km or more) earthquakes. Several members of the PSN have had success building the broadband vertical seismometer that I describe at: http://www.eas.slu.edu/People/STMorrissey/ stmseis.html" The STM-8 Leaf Spring Seismometer: Photos and Report stmfigs.html" The STM-8 Seis: Figures, Schematics, Drawings stmquakes.html" The STM-8 Seis: Recent Quakes, Data A major advantage of this design is that the instrument response, including the damping, is mostly controlled by electronic components of the feedback system, so the response is linear and calibrated over a wide range regardless of variations on the the mechanical behavior of the sensor such as the mechanical period. A significant advantage of a very broadband response is that when most of the earthquake energy is within the "flat" portion of the velocity response, the shape of the response does not have to be considered in analyzing the data. Like for a teleseism with 1hz P waves and 20 to 60 second surface waves, a VBB response that is flat from 30hz to 120 seconds will accurately record all the ground motion. THis can be seen in some of the data samples where comparison is made to regional broadband stations, (which have commercial VBB sensors that are flat from 20hz to 360 seconds) and the waveform differences are mostly because of different ray paths to the stations from the earthquake source in south America. The mechanics of the assembly of the hardware-store seismometer are pretty straight forward, and the electronics can be assembled on a perforated type circuit board if you can read a schematic and do soldering. I am hoping to get a local company to prefab the electronics into a "plug and play" box that hopefully won't cost more than $100. I am currently recycling circuits from other projects for the prototypes I have built, so the circuits appear more complex than necessary. I have recently re-worked the 4-amplifier card to include the integrator, so the instrumentation-style amplifier is not needed. I haven't scanned and posted the revision...... yet. We have had a wide assortment of discussions of the construction details on the PSN. However, I don't think they have been organized in any sense. I am working with a local instrumentation company try to produce a complete version of the hardware-store seismometer. It will be hopefully be available next fall and cost $800 or more. 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 From: "David A. Nelson" Subject: MAJ QUAKE !!!!!!!!!!1 NOWWWW Date: Sun, 7 Feb 1999 10:57:10 +1300 MAJOR QUAKE in progress 2156 UT 06 feb Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://www.seismicnet.com/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 From: Larry Cochrane Subject: Re: MAJ QUAKE !!!!!!!!!!1 NOWWWW Date: Sat, 06 Feb 1999 14:07:32 -0800 I love it when email about a new event arrives before the P wave. P wave hit here around 22:02:00 UTC -Larry At 10:57 AM 2/7/99 +1300, you wrote: > MAJOR QUAKE in progress 2156 UT 06 feb > > >Dave >Co-ordinator: >New Zealand >Public Seismic Network > Dave A. Nelson ZL4TBN > 24 Jensen St., > Green Is., Dunedin, > South Is.. New Zealand. > >http://www.seismicnet.com/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) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Liberio Rossi" Subject: Quake in progress!!!!!!! Date: Sat, 6 Feb 1999 23:51:02 +0100 Here recorded P wave 22.06.00 lat.43.54.79n long.1031.56 From: "." Subject: R: MAJ QUAKE !!!!!!!!!!1 NOWWWW Date: Sun, 7 Feb 1999 00:01:48 +0100 SIRACUSA (Sicily) Pkp wave hit here around 22:07 UTC Claudio Conti CONTI CLAUDIO conticl@........... -----Messaggio originale----- Da: Larry Cochrane [SMTP:cochrane@............... Inviato: sabato 6 febbraio 1999 23.08 A: PSN-L Mailing List Oggetto: Re: MAJ QUAKE !!!!!!!!!!1 NOWWWW I love it when email about a new event arrives before the P wave. P wave hit here around 22:02:00 UTC -Larry At 10:57 AM 2/7/99 +1300, you wrote: > MAJOR QUAKE in progress 2156 UT 06 feb > > >Dave >Co-ordinator: >New Zealand >Public Seismic Network > Dave A. Nelson ZL4TBN > 24 Jensen St., > Green Is., Dunedin, > South Is.. New Zealand. > >http://www.seismicnet.com/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) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: NO ATTACHMENTS PLEASE and station ID's Date: Sat, 06 Feb 1999 15:23:05 -0800 Everyone, This is a not so gentle reminder that attachments should NOT be sent to this list. If you have an event file, please send it the archive system at event@............... This way it will get placed on my FTP / Web server system so others can download it. All other files should be posted on a web site somewhere and the URL sent out on the list. And while I'm at it... If you are running a PSN station and send in event files, please us a unique station / sensor ID. Please don't use the default SDR channel names (event file extension) of *.CH1, *.CH2 etc. Thanks, -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Re: Advice/Recommendations Date: Sat, 06 Feb 1999 16:45:09 -0700 Sean- However they are relatively easy to understand and construct working models of, and their data has been routinely posted to the PSN since the first BBS in 1991. -Edward S-T Morrissey wrote: > The homemade sensors you ask about (Lehman, SG) are very primitive (my opinion) > designs that don't even encompass modern concepts of seismometer design. > They are also horizontal sensors so they respond poorly to the primary > waves of distant (1000 km or more) earthquakes. -- 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 From: S-T Morrissey Subject: Re: Advice/Recommendations Date: Sat, 6 Feb 1999 18:24:51 -0600 (CST) Edward, I fully agree with what you say about the Lehman and SG designs. They do work, and those who have made them and continue to operate them should be commended. I am only trying the raise the bar; I believe that we can do better. Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: Mb 7.3, Santa Cruse Isl. Date: Sat, 6 Feb 1999 18:27:57 -0600 (CST) The following near-real-time Earthquake Bulletin is provided by the National Earthquake Information Service (NEIS) of the U. S. Geological Survey as part of a cooperative project of the Council of the National Seismic System. For a description of the earthquake parameters listed below, the availability of additional information, and our publication criteria, please finger qk_info@.................. 99/02/06 21:47:59 12.96S 166.67E 90.2 7.3Ms B SANTA CRUZ ISLANDS _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Re: Rough Draft of Seismograph Theory Page Date: Sat, 06 Feb 1999 17:59:25 -0700 John- I liked the graphics but not the equations: one of the reasons I stayed in field seismology was to stay away from the black boards ... but that's my prejudice. -Edward John Hernlund wrote: > Hello Everyone, > Because of many requests for information and general questions about > seismographs from people on the internet and in my community I have decided to > undertake a project that describes the way seismometers work both > mathematically and graphically. This is because I can never find a good book > to refer people to that ties all the concepts together. I have only covered > material pertaining to simple damped seismometers, but I plan to add more > material as I go eventually describing some of the mathematics of various > filters, the sampling process, Fourier Analysis, and other usually advanced > and scattered topics. > > It is only a rough draft now, but I thought the PSN would be the perfect > place to ask for a review and suggestions on what has been completed thus far. > If you get the chance, read through it, and e-mail me any > comments/suggestions that you have. Be honest: if it sucks and doesn't make > any sense at all, then let me know because you won't be the first to feel that > way! > > ****************************************************************************** > > John Hernlund > E-mail: 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 -- 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 From: George Bush Subject: Mystery quake close to Sea Ranch, CA, USA Date: Sat, 06 Feb 1999 17:04:05 -0800 Hello: I detected a sharp earthquake 02-05-99 at 19:16 PT (time approximate to + or - 5 min.) that had a 4.4 second difference between easily-seen P and S waves for a distance from here of 4mi.! I was not abe to find anything listed on the USGS site of recent earthquakes? If you have any other sources I would be interested in knowing if anyone else has seen it and where this quake was located. You can go to http://psn.quake.net/cgi-dos/event.exe and see it. Look for the event file with the .tsr extension. George Bush Sea Ranch, CA, USA 38.74N, 123.5W _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Re: New WinQuake beta release Date: Sat, 06 Feb 1999 20:12:23 -0700 Larry & Arie- I have fallen behind in keeping up with what you guys have been doing with the new WinQuake and Autodrm but ... IT IS SIMPLY MIND-BOGGLING!!!! -Edward Larry Cochrane wrote: > Hi Everyone, > > Happy New Year. In the last few months I have been working on a new > Winquake (WQ) release. With some help from Arie Verveer (thanks Arie!) I > think I have a stable beta release ready.I sent Arie a pre-beta release so > he could checkout one of the new features in this release. I used the code > he wrote to convert GSE2.0 files to the PSN format to allow WQ to view > event files in that format. He ended up finding a few major bugs that where > not happening on my system. -- 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 From: Angel Rodriguez Subject: Re: Advice/Recommendations Date: Sun, 7 Feb 1999 17:27:34 -0500 At 07:02 AM 02/05/1999 -0500, you wrote: >I am looking for advice and recommendations as to what type of seismometer >(vertical, horizontal, GS, Lehman, etc) I should install for amateur use in >my home. I would be like to keep the cost in the $2000 to $3000 range. I am >located in central Ohio. I want to acquire the data on a PC which I have >and can dedicate for this use. Hi, There is a company in Switerland that sella complete 3 axis package with GPS time refernce for less that 3000.00. It comes complete with data logging software and Seisan for looking at =F1the data. The call it the GBV-316 Seismic Recorder and it has 4.5 hz geophones inside, 2 meg of memory, ring buffers, self diagnostics, and will connect to your PC thru the serial port or thru a modem. Transfer factor 28 Vs/m gain of 10, 100, 1000 jumper selectable 16 bit AtoD Their email is geosys@.......... You can also get most of the electronics from Larry and build your own devices, which is half the fun anyway. Hope it helps, A. Rodriguez _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Speaker magnet Date: Sun, 07 Feb 1999 18:18:51 -0800 Hi All For increasing the gap of a speaker magnet it is necessary to file, machine or whatever the metal plates. As a note, I soaked the magnet in carburetor cleaner for a week or so and it dissolved the adhesive between the magnet and the plates. Regards Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: robert barns <75612.2635@..............> Subject: Re: Advice/Recommendations Date: Mon, 8 Feb 1999 12:02:00 -0500 The Swiss device has 4.5 Hz geophones which would work ONLY with local events. This would be no good for seeing events worldwide. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: TMichel917@....... Subject: Re: Advice/Recommendations Date: Mon, 8 Feb 1999 12:22:39 EST The GBV-316 is also available as digitizer only. You can connect other sensors than the internal SM-6 4,5 Hz geophone to this digitizer. Detailed information is available at: http://www.geosys.ch Torsten Michel _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: File transfering Date: Tue, 09 Feb 1999 22:07:57 -0800 I was reading the latest issue of Sensors magazine and I was reminded of a question I ment to ask a while back. I was wondering how easy it would be to connect a cellular phone at a remote seismic site to a base station computer. I wouldn't mind the daily cost of a local phone call it I could receive the days data from a remote station. The plan would be to dial the cell phone number from my house modem. This call would interupt the EMON , SDR or other DOS acquisiton program. I would download the days data, clear the memory and hang up. I would need modems at both ends but is the software out there? Regards Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Re: File transfering Date: Tue, 09 Feb 1999 23:14:57 -0700 Barry- We have been messing around with this at USGS for a couple of years now, and it has been a real pain. We ran a remote site in Seattle by cell-phone for several months, and we are about to put in several other sites. I will CC this reply to Mark Meremote who is the working on this system. -Edward barry lotz wrote: > I was reading the latest issue of Sensors magazine and I was > reminded of a question I ment to ask a while back. I was wondering how > easy it would be to connect a cellular phone at a remote seismic site to > a base station computer. I wouldn't mind the daily cost of a local phone > call it I could receive the days data from a remote station. The plan > would be to dial the cell phone number from my house modem. This call > would interupt the EMON , SDR or other DOS acquisiton program. I would > download the days data, clear the memory and hang up. I would need > modems at both ends but is the software out there? > Regards > Barry > > _____________________________________________________________________ > > 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 From: Edward Cranswick Subject: Re: File transfering Date: Tue, 09 Feb 1999 23:16:00 -0700 PS. What kind of sensors are you now recording? barry lotz wrote: > I was reading the latest issue of Sensors magazine and I was > reminded of a question I ment to ask a while back. I was wondering how > easy it would be to connect a cellular phone at a remote seismic site to > a base station computer. I wouldn't mind the daily cost of a local phone > call it I could receive the days data from a remote station. The plan > would be to dial the cell phone number from my house modem. This call > would interupt the EMON , SDR or other DOS acquisiton program. I would > download the days data, clear the memory and hang up. I would need > modems at both ends but is the software out there? > Regards > Barry > > _____________________________________________________________________ > > 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 From: Larry Cochrane Subject: Re: Winquake problem Date: Tue, 09 Feb 1999 22:22:57 -0800 At 12:54 PM 2/8/99 -0400, you wrote: >Hello Larry > >I just noticed a problem with the new release of Winquake which I >thought I would bring to your attention. Whenever I save as a GIF image, >I cannot close the event file and open another. The system tells me that >it cannot find the files. > >Wayne Wayne, I can't duplicate this problem. I'm CCing the PSN-L list to see if anyone else has seen this problem. Does this problem happen only on the event window, or does it happen when you save a FFT or map window as a gif image? -Larry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Karl Cunningham Subject: Re: File transfering Date: Wed, 10 Feb 1999 09:27:31 -0800 Barry -- I don't have any direct experience with this, but the California Department of Transportation is using a cellular-phone based system to download data from solar-powered weather stations along remote highways. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... At 10:07 PM 2/9/99 -0800, you wrote: > I was reading the latest issue of Sensors magazine and I was >reminded of a question I ment to ask a while back. I was wondering how >easy it would be to connect a cellular phone at a remote seismic site to >a base station computer. I wouldn't mind the daily cost of a local phone >call it I could receive the days data from a remote station. The plan >would be to dial the cell phone number from my house modem. This call >would interupt the EMON , SDR or other DOS acquisiton program. I would >download the days data, clear the memory and hang up. I would need >modems at both ends but is the software out there? _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "James M Hannon" Subject: Re: File transfering Date: Wed, 10 Feb 1999 15:51:42 -0600 A friend of mine at work did something like this for a transmitter locating experiment using remote receivers. He used a program called Doorway which basically lets you log onto the remote PC via the dial up phone connection. Unfortunately I cannot find any other information on Doorway. But another program called PCanywhere will also do the same job http://www.symantec.com/pcanywhere/fs_pcawin20.html. The programs are both dos based. I am not 100% sure but I think that with PCanywhere you wouldn't even have to interrupt the operation of the EMON or SDR to log in and download your data files. Jim Hannon barry lotz on 02/10/99 12:07:57 AM Please respond to PSN-L Mailing List To: psn list cc: Subject: File transfering I was reading the latest issue of Sensors magazine and I was reminded of a question I ment to ask a while back. I was wondering how easy it would be to connect a cellular phone at a remote seismic site to a base station computer. I wouldn't mind the daily cost of a local phone call it I could receive the days data from a remote station. The plan would be to dial the cell phone number from my house modem. This call would interupt the EMON , SDR or other DOS acquisiton program. I would download the days data, clear the memory and hang up. I would need modems at both ends but is the software out there? Regards 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) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Francesco Subject: Re: File transfering Date: Wed, 10 Feb 1999 23:16:44 +0100 Hi guy. In our network, we courrently use PcAnywhere (freeware) to download, via modem pc to pc, the files of the remote stations. No conflict or interruption with Sdr in progress or with other programs. PcAnywhere runs under Dos too. Another system that I use is the Microsft Plus extension, wich is able to connect two or many remote pc via modem (this is an utility of the "remote access"), with the file's condivision. But it require W95 platform (I take run Sdr under Win95 - Dos application - in a Pentium 350 without problems). Win98 don't require MSoft Plus bucause include this option. Regards Francesco Nucera I.E.S.N. - PSN Italy _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: ralvarez@........ (Raul Alvarez) Subject: Re: File transfering Date: Wed, 10 Feb 1999 18:17:46 -0700 (MST) Hello, Do you know if PCAnywhere is available on the internet? Raul >Hi guy. >In our network, we courrently use PcAnywhere (freeware) to download, via >modem pc to pc, the files of the remote stations. >No conflict or interruption with Sdr in progress or with other >programs. >PcAnywhere runs under Dos too. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ "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) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Interesting article on sensors. Date: Wed, 10 Feb 1999 18:14:44 -0800 Hi Everyone, Interesting article on sensor at http://www.sensorsmag.com/toc_0299.htm. Select the "A practical Approach to Vibration..." link. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Francesco Subject: Re: File transfering Date: Thu, 11 Feb 1999 08:42:52 +0100 Try at http//www.symantec.com But PcAn is a very large programm. the latest version is more than 4 mb You should find it in some commercial cd internet newspaper... Francesco Nucera I.E.S.N. PSN Italy _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: File transfering Date: Thu, 11 Feb 1999 19:20:28 -0800 Edward I currently have one ~30 sec Lehman, two homemade STM verticals(24"&12") and one geophone(Gateway electronics $10 special). I'm currently constructing a horizontal like STM posted on his web site. I was hopeing to incorporate the "triple" feedback with it. They are all connected to my house via shielded cables. I would like to install one in a remote location (mine shaft or up on the Sierra Nevada mtns). Crank the gain up. Regards Barry Edward Cranswick wrote: > PS. What kind of sensors are you now recording? > > -- > Edward Cranswick Tel: 303-273-8609 > US Geological Survey, MS 966 Fax: 303-273-8600 > PO Box 25046, Federal Center cranswick@........ > Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: File Transfering Date: Thu, 11 Feb 1999 19:34:23 -0800 Thanks all! I'll try to upload and work with pcanywhere. I think experiment by putting a 286 computer in my garage with the sensors and try to connect it with the house. Sensors magazine said they had better luck with low speed modems (1200 baud).We'll see if I can get it to work with Emon and an extra Acqutek 12 bit board. Thanks again for the response. Regards Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: File transfering Date: Thu, 11 Feb 1999 19:57:04 -0800 Francesco I'm not cheap ---but I only found the $150 version on the internet. Barry Francesco wrote: > Hi guy. > In our network, we courrently use PcAnywhere (freeware) to download, via > modem pc to pc, the files of the remote stations. > No conflict or interruption with Sdr in progress or with other > programs. > PcAnywhere runs under Dos too. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Re: File transfering Date: Thu, 11 Feb 1999 20:13:30 -0800 PC Anywhere is not freeware. They have a demo version that runs of 30 or 45 days available on there web site, but it is only for Win95/98/NT. The DOS / Win 3.1 version is not available for download. On their web site the cost was $179.00 for the DOS / Win 3.1 version. I use the 32 bit version of PC Anywhere almost every day for remotely maintain several NT systems on the Internet. Its a great program! Even when I had the 28K connection to the net, it was very useful. Now that I have the DSL line it's almost like being at the remote computer. Francesco, it is very good news that the DOS version (I have never used the DOS / Win 3.1 version) runs with EMON and SDR. Thanks for the information. -Larry Cochrane Redwood City, PSN At 07:57 PM 2/11/99 -0800, you wrote: >Francesco > I'm not cheap ---but I only found the $150 version on the internet. > Barry > > >Francesco wrote: > >> Hi guy. >> In our network, we courrently use PcAnywhere (freeware) to download, via >> modem pc to pc, the files of the remote stations. >> No conflict or interruption with Sdr in progress or with other >> programs. >> PcAnywhere runs under Dos too. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Fwd: origin of name of Lehman(n) sensor Date: Thu, 11 Feb 1999 23:03:29 -0800 FYI, Ken and I received this today.... -Larry >Date: Thu, 11 Feb 1999 22:54:55 -0800 >From: Ed Thelen >Reply-To: ethelen@........ >Organization: @Home Network >X-Mailer: Mozilla 4.05 [en]C-AtHome0402 (Win95; I) >To: kjn@.......... >CC: cochrane@.............. >Subject: origin of name of Lehman(n) sensor > >While reading > http://www.seismicnet.com/info/homefaq.txt > >I saw question >" >Aside: > No one seems to know if the Lehman(n) sensor is named after the >author, > James D. Lehman, or the famed Danish seismologist, Inge Lehmann, >who > published a paper in 1936, that postulated that the earth held >an inner > core estimated to be about the size of our moon within the outer >core. > If someone has some information on this please forward it to me > so I can include it in the next update of the FAQ. >(kjn@........... >" > >I was editor of WASS (World Amateur Seismological Society) - RIP - >in the early 1970s. > 1) long period instruments - say from Springneither (sp) > or of amateur construction were informally called > "garden gate" or "Galtzin" (sp) style > 2) I never heard of a "Lehman" style - >so assume that the Lehman style is due to James D. > >-------------------- > >I cannot comprehend why someone would construct >such a weak, complex double vertical post >"Lehman" design using 3/4 inch tubing. > - poor rigidity > - ridiculous to analyze for vibrations > - low frequency natural resonance > >The several instruments I constructed were of >2 inch copper tubing and had a single >vertical post - sturdy, quite rigid, >high natural resonance frequency. > >Cheers > Ed Thelen > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Francesco Subject: Re: File transfering Date: Fri, 12 Feb 1999 08:42:11 +0100 Barry, If you decide to use PcAn and if you don't find it in another way, if you want I can send you the floppy. Francesco _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Steve Hammond Subject: Re: File transfering Date: Fri, 12 Feb 1999 23:15:51 -0800 Hi Barry, Larry, Ed, and Others, I was reading the MEIAL string and wanted to add a few comments about some EMON features Ted had been working on and a comment or two about PCAnywhere. Ted started working on a version of EMON that could be setup to page a pager, drop to DOS run a Bat file, and clean up files based on time, day or event. During testing it hung a few times, and at the PSN meeting Ted said he would look at it and make repairs when he had time. Don't know where that stands today. Guess I better drop Ted a line... It was very cool when it worked. PCAnywhere In 1991, my brother and loaded PCAnywhere on a PC2 running SDAS. It worked as adverstised and displayed/accepted input in realtime from the remote console / keyboard. 1200 BAUD was a bit too slow. However, I was able to transfer data from the remote site on demand. Regards, Steve Hammond PSN San Jose, California barry lotz wrote: > > I was reading the latest issue of Sensors magazine and I was > reminded of a question I ment to ask a while back. I was wondering how > easy it would be to connect a cellular phone at a remote seismic site to > a base station computer. I wouldn't mind the daily cost of a local phone > call it I could receive the days data from a remote station. The plan _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: File transfering Date: Fri, 12 Feb 1999 20:11:30 -0800 Hi Everyone I went by Compusa today and Pcanywhere comes with a DOS and windows version included. Not to belabor the string but the next step for me is tying it to a cell phone. The store says that the modem used has to be "cellular compatable". It seems that the new modems would be more likely to be "cell compatable"(what ever that means) but new modems may be less likely to run under DOS. It seems to me that a remote site should be bare bones ie. low power and memory saved for event files and not operating system. Can one get DOS, low power modems that can work with analog cell phones? I would use a passive backplane system with processor card. Regards Barry ps. I have a Motorola analog flip phone I would like to use. I assume the modem line and the power all come into the phone bottom. (12 volt battery and modem line) > Hi Barry, Larry, Ed, and Others, > I was reading the MEIAL string and wanted to add a few comments about > some EMON features Ted had been working on and a comment or two about > PCAnywhere. Ted started working on a version of EMON that could be setup > to page a pager, drop to DOS run a Bat file, and clean up files based on > time, day or event. During testing it hung a few times, and at the PSN > meeting Ted said he would look at it and make repairs when he had time. > Don't know where that stands today. Guess I better drop Ted a line... It > was very cool when it worked. > > PCAnywhere > In 1991, my brother and loaded PCAnywhere on a PC2 running SDAS. It > worked as adverstised and displayed/accepted input in realtime from the > remote console / keyboard. 1200 BAUD was a bit too slow. However, I was > able to transfer data from the remote site on demand. > > Regards, Steve Hammond > PSN San Jose, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Rudolph Norvelle" Subject: Setting up a seismograph Date: Fri, 12 Feb 1999 21:02:21 -0800 Hello, I am in the midst of trying to set up a Lehman seismograph. = However before I get started I want to determine the best spot in my = house to set it up. Does anyone have experience with setting upn their = seismograph in there garage. would the foot traffic be a problem? = Fortunatly my house is on a cul-de-sac so there is not a whole lot of = automobile traffic, but there are a lot of kids running around. Would = it be more practical if I tried to place the sensor under my house in an = insulated case, etc? Any help would be appreciated. Thanks in advance. Rudy Norvelle
    Hello,
        I am in the = midst of=20 trying to set up a Lehman seismograph.  However before I get = started I want=20 to determine the best spot in my house to set it up.  Does anyone = have=20 experience with setting upn their seismograph in there garage. would the = foot=20 traffic be a problem?   Fortunatly my house is on a cul-de-sac = so=20 there is not a whole lot of automobile traffic, but there are a lot of = kids=20 running around.  Would it be more practical if I tried to place the = sensor=20 under my house in an insulated case, etc?  Any help would be=20 appreciated.
 
         &nb= sp;           &nbs= p;            = ; =20 Thanks in advance.
         &nb= sp;           &nbs= p;            = ;   =20 Rudy Norvelle
From: Ken Navarre Subject: Re: origin of name of Lehman(n) sensor Date: Fri, 12 Feb 1999 21:25:14 -0800 (PST) On Thu, 11 Feb 1999, Ed Thelen wrote: > While reading > http://www.seismicnet.com/info/homefaq.txt > > I saw question " Aside: > No one seems to know if the Lehman(n) sensor is named after the > author, James D. Lehman, or the famed Danish seismologist, Inge Lehmann, > who published a paper in 1936, that postulated that the earth held > an inner core estimated to be about the size of our moon within the outer > core. > If someone has some information on this please forward it to me > so I can include it in the next update of the FAQ. > (kjn@........... > I was editor of WASS (World Amateur Seismological Society) - RIP - > in the early 1970s. > 1) long period instruments - say from Springneither (sp) > or of amateur construction were informally called > "garden gate" or "Galtzin" (sp) style > 2) I never heard of a "Lehman" style - > so assume that the Lehman style is due to James D. Hi Ed, your assumption is quite correct. As a matter of fact A year or so ago I got an e-mail from James D. Lehman. He was quite suprized that his sensor had become so popular. He also confirmed that he and Inge were not related although he also confirmed that he would have certainly been proud to have her in his family tree! (as would most of us...) Ken _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Frank Cooper" Subject: Re: Setting up a seismograph Date: Sat, 13 Feb 1999 00:31:00 -0600 HI Rudy, Following is my personal experience. My Lehman is set up near my double = garage overhanging door (the car entrance which I do not use). I can = use approx. 1/2 the garage on the side opposite the seismograph. On the = side opposite the garage overhanging car door are located the person = entrance door, a washing machine, a drier, a table saw, and the = seismograph computer read-outs and chart recorder, all of which I use = without significant inteference with the Lehman. However, I cannot go = into the half of the garage with the Lehman without throwing the chart = recorder and electronic reading off scale. I tell my grand daughters = the half of the garage with the seismograph is off-limits. I draw a = line which I tell them not to cross. Nor do I cross it unless I turn = off the amps first. I live on a heavily travelled street about 40 feet = from the garage car entrance and the seismograph. I "see" every vehicle = that goes by on the CRT but fortunately Larry Cochrane's software = filters out most of this inteference. If I stand immediately outside = the car entrance overhead doors the seismograph read-outs are thrown off = scale. I park my cars on the driveway and walk behind my cars when I = walk past the garage. I don't walk immediately in front of the garage = door. One morning about three am as I was studying the computer CRT and = chart recorder I realized that someone was standing just outside my = garage door and in front of my astrovan. Fortunately he ran when I went = out the person door.=20 Eventually I plan to locate two seismic instruments behind the house in = a low roll-off shed with concrete foundation. Hope this helps. Frank Cooper, Friendswood, Texas, USA -----Original Message----- From: Rudolph Norvelle To: PSN-L@.............. Date: Friday, February 12, 1999 11:08 PM Subject: Setting up a seismograph =20 =20 Hello, I am in the midst of trying to set up a Lehman seismograph. = However before I get started I want to determine the best spot in my = house to set it up. Does anyone have experience with setting upn their = seismograph in there garage. would the foot traffic be a problem? = Fortunatly my house is on a cul-de-sac so there is not a whole lot of = automobile traffic, but there are a lot of kids running around. Would = it be more practical if I tried to place the sensor under my house in an = insulated case, etc? Any help would be appreciated. =20 Thanks in advance. Rudy Norvelle
HI Rudy,
Following is my personal experience.  My Lehman = is set up=20 near my double garage overhanging door (the car entrance which I do not=20 use).  I can use approx. 1/2 the garage on the side opposite the=20 seismograph.  On the side opposite the garage overhanging car door = are=20 located the person entrance door, a washing machine, a drier, a table = saw, and=20 the seismograph computer read-outs and chart recorder, all of which I = use =20 without significant inteference with the Lehman.  However, I cannot = go into=20 the half of the garage with the Lehman without throwing the chart = recorder and=20 electronic reading off scale.  I tell my grand daughters the half = of the=20 garage with the seismograph is off-limits.  I draw a line which I = tell them=20 not to cross.  Nor do I cross it unless I turn off the amps = first.  I=20 live on a heavily travelled street about 40 feet from the garage car = entrance=20 and the seismograph. I "see" every vehicle that goes by on the = CRT but=20 fortunately Larry Cochrane's software filters out most of this=20 inteference.  If I stand immediately outside the car entrance = overhead=20 doors the seismograph read-outs are thrown off scale.  I park my = cars on=20 the driveway and walk behind my cars when I walk past the garage. I = don't walk=20 immediately in front of the garage door.  One morning about three = am as I=20 was studying the computer CRT and chart recorder I realized that someone = was=20 standing just outside my garage door and in front of my astrovan. =20 Fortunately he ran when I went out the person door.
 
Eventually I plan to locate two seismic instruments = behind the=20 house in a low roll-off shed with concrete foundation.
Hope this helps.
Frank Cooper, Friendswood, Texas, USA
-----Original = Message-----
From:=20 Rudolph Norvelle <Rudy43Norvelle@........... tt.net>
To:=20 PSN-L@.............. = <PSN-L@..............>
D= ate:=20 Friday, February 12, 1999 11:08 PM
Subject: Setting up = a=20 seismograph

    Hello,
        I am in = the midst=20 of trying to set up a Lehman seismograph.  However before I get = started=20 I want to determine the best spot in my house to set it up.  = Does=20 anyone have experience with setting upn their seismograph in there = garage.=20 would the foot traffic be a problem?   Fortunatly my house = is on a=20 cul-de-sac so there is not a whole lot of automobile traffic, but = there are=20 a lot of kids running around.  Would it be more practical if I = tried to=20 place the sensor under my house in an insulated case, etc?  Any = help=20 would be appreciated.
 
         &nb= sp;           &nbs= p;            = ; =20 Thanks in advance.
         &nb= sp;           &nbs= p;            = ;   =20 Rudy Norvelle
From: Karl Cunningham Subject: Re: Setting up a seismograph Date: Sat, 13 Feb 1999 01:18:25 -0800 Hi Rudy -- I have a force-balance Lehman-style seismometer on the floor of my garage. Lehman-type seismometers are quite sensitive to tilting of the seismometer base. Mine works just fine, but does see footsteps anywhere in the garage or immediately outside. The major problem is not the relatively high frequency footsteps, but tilt of the garage slab when walking within about 8 feet of the instrument. In fact, a cat walking about 3 feet away on the slab will set off the event alarm. The house is about 45 years old and the dirt under the slab may have settled somewhat, resulting in less support under the slab. Or maybe this is just the way it is. If I am working in the garage, I can plan on not seeing any small events during that time, and getting many false alarms. Also, walking on a brick sidewalk right outside the garage causes an alarm about half the time. It's not the best arrangement, but a satisfactory compromise. One day I hope to build an outside shed over stable granite and house my instruments there. Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... At 09:02 PM 2/12/99 -0800, you wrote: >>>> Hello, I am in the midst of trying to set up a Lehman seismograph. However before I get started I want to determine the best spot in my house to set it up. Does anyone have experience with setting upn their seismograph in there garage. would the foot traffic be a problem? Fortunatly my house is on a cul-de-sac so there is not a whole lot of automobile traffic, but there are a lot of kids running around. Would it be more practical if I tried to place the sensor under my house in an insulated case, etc? Any help would be appreciated. Thanks in advance. Rudy Norvelle <<<<<<<< _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: RLLaney@....... Subject: Re: Setting up a seismograph Date: Sat, 13 Feb 1999 11:38:34 EST Hi Rudy: I have a Lehman and SG seismograph on the floor of my double-car garage. I park my pickup within 3 feet of the instruments. They are very sensitive to foot traffic in the garage, movement of nearby trees, and even low flying helicoptors. When I move the truck in or out of the garage I get a "magnitude 1,000" event. When I am working in or near the garage I set the threshold on the SDR software at a maximum so that I do not record all this noise. Even with all of these noise sources, I was able to record more than 40 earthquakes and many quarry blasts last year and only missed one earthquake because I was working in or near the garage at the time. The way I look at it, seismology is a hobby for me--and a good one, too!--but it has to fit into my mode of living. I can't let the seismograph control me. So, I suggest that you go ahead and put yours in the garage and see how it works. You may be surprised. Regards, Bob Laney Herndon, VA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Steve Hammond Subject: Re: Fwd: origin of name of Lehman(n) sensor Date: Sat, 13 Feb 1999 17:12:36 -0800 Larry Cochrane wrote: > > FYI, Ken and I received this today.... > -Larry > > >Date: Thu, 11 Feb 1999 22:54:55 -0800 > >From: Ed Thelen > >Reply-To: ethelen@........ > >Organization: @Home Network > >X-Mailer: Mozilla 4.05 [en]C-AtHome0402 (Win95; I) > >To: kjn@.......... > >CC: cochrane@.............. > >Subject: origin of name of Lehman(n) sensor > > > >While reading > > http://www.seismicnet.com/info/homefaq.txt > > > >I saw question > >" > >Aside: > > No one seems to know if the Lehman(n) sensor is named after the > >author, > > James D. Lehman, or the famed Danish seismologist, Inge Lehmann, > >who > > published a paper in 1936, that postulated that the earth held > >an inner > > core estimated to be about the size of our moon within the outer > >core. > > If someone has some information on this please forward it to me > > so I can include it in the next update of the FAQ. > >(kjn@........... > >" > > > >I was editor of WASS (World Amateur Seismological Society) - RIP - > >in the early 1970s. > > 1) long period instruments - say from Springneither (sp) > > or of amateur construction were informally called > > "garden gate" or "Galtzin" (sp) style > > 2) I never heard of a "Lehman" style - > >so assume that the Lehman style is due to James D. > > > >-------------------- > > > >I cannot comprehend why someone would construct > >such a weak, complex double vertical post > >"Lehman" design using 3/4 inch tubing. > > - poor rigidity > > - ridiculous to analyze for vibrations > > - low frequency natural resonance > > > >The several instruments I constructed were of > >2 inch copper tubing and had a single > >vertical post - sturdy, quite rigid, > >high natural resonance frequency. > > > >Cheers > > Ed Thelen > > > > _____________________________________________________________________ > > 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 From: Steve Hammond Subject: Re: Fwd: origin of name of Lehman(n) sensor Date: Sat, 13 Feb 1999 17:18:39 -0800 Hi ken-- I came across the attached note the other day. It talks about James Lehman, posted by Bob Barns. Regards, Steve Larry Cochrane wrote: > > FYI, Ken and I received this today.... > -Larry > > >Date: Thu, 11 Feb 1999 22:54:55 -0800 Subject: James Lehman Date: Wed, 3 Jun 1998 20:32:25 -0400 From: robert barns <75612.2635@..............> Reply-To: PSN-L Mailing List To: PSN-L Mailing List Hi gang, The '79 Sci. Am. article on the Lehman seismograph attributed the design to James D. Lehman at James Madison U. in Harrisonburg, VA. Hotbot quickly gave me the URL of the school (www.jmu.edu/). This site is very attractive and complete. He is listed (with a photograph) in the Physics department along with his 'phone no. I called him to see if he is still interested in seismology. We had a long chat and he still runs his rig with a strip chart recorder. He is especially interested in microseisms. He modestly says that he never refers to the design as a Lehman but I think that he faces an impossible job if he ever tries to get us to change. He sez that he monitors the PSN e-mail and has been in touch with Larry in the past. His e-mail address is lehmanjd@........ Bob Barns Why do psychics have to ask you for your name? No one seems to know if the Lehman(n) sensor is named after the > >author, > > James D. Lehman, or the famed Danish seismologist, Inge Lehmann, > >who > > published a paper in 1936, that postulated that the earth held _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "David A. Nelson" Subject: files that crash winquake Date: Mon, 15 Feb 1999 09:46:11 +1300 hi all, tony and I are finding a lot of the files from one of the italian stations crash winquake when we try to view these files. is it just us 2 or are others having problems too.?? I have had to delete many of the files cuz they jst cannot be viewed here are some of the files in question...... 130299b.wq1 02/13/99 22:57:00 Sicily area (E) 140299b.wq1 02/14/99 22:57:00 Siracusa, Italy espri.wq1 02/14/99 patti's gulf 140299a2.wq1 02/14/99 13:31:00 Siracusa, Italy there are many others that also crash winquake i have no idea why its happening they just cause WQ to do an illegal operation jst on a sideline it would be nice if people could use the standard yr mth day eg. 990214a.lpn rather than as the ones above that have that opposite or using a placename for the file name. It makes life a lot easier for those of us who archive posted events, as when we are looking for/working with files in windows explorer etc, file manager, the files are then in chronological order. It is time consuming having to rename these files so they will appear in chronological order. Thanks :) Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://www.seismicnet.com/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 From: "David A. Nelson" Subject: also meant to add Date: Mon, 15 Feb 1999 09:59:53 +1300 forgot to include I'm using WQ Version 2.5.2 32bit Tony is using Version 2.4 32 bit Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://www.seismicnet.com/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 From: S-T Morrissey Subject: horizontal tilt noise Date: Mon, 15 Feb 1999 01:01:23 -0600 (CST) Re: tilt sensitivity of horizontal seises: Regarding the recent question of finding a suitable site for a Lehman type horizontal seismometer: the problem is the extreme tilt sensitivity of a horizontal compared to a vertical sensor of the same period. In a nutshell, the tilt sensitivity of the vertical is proportional to the square of the tilt angle, while a horizontal is sensitive to the angle itself. Since we are dealing with small angles measured in radians, the squared value is much smaller. The formula for the tilt sensitivity of the horizontal pendulum: (which can be used to calibrate the displacement detector) z = (g * Tn^2 / 4 * pi^2) * phi where z is the horizontal displacement of the mass, Tn is the natural period, and phi is the tilt of the base at right angles to the boom, again measured in radians. g = 980cm/sec^2; z = cm. As an example: from experience in repeatedly adjusting the old S5100 for about 1mm of boom displacement: the base is 500 mm, so the tilt from 1/100 turn of the screw ( which is 0.008 mm) is 0.008/500 = 0.000016 radian. If Tn = 15 seconds, the mass will move 0.89 mm, which is close to what is observed. For the garage floor site, if we assume a 15 second horizontal seis and that the floor tilts by 0.001 radian (there are 2*pi radians in 360 degrees, so a radian is 57.3 degrees, so our floor is tilting only 0.057 degree. It doesn't sound like much, but the seismometer mass will move 55 mm because of it. Or if the output is 55 microns (displacement), the floor tilted one microradian. For a vertical seismometer, tilting the base will change the force of gravity that is normally exactly parallel to the force of the spring, reducing it slightly. The formula works out to: z = (g * Tn^2 / 8 * pi^2) * phi^2 For our floor tilt example above, the angle (0.001 radian) is squared, so the mass of the vertical will only move 27.5 MICRONS due to the same 0.001 rad. tilt. This effect is often used to absolutely calibrate vertical displacement sensors, such as gravimeters and VBB instruments. So it is clear that finding a suitable site for a long-period horizontal is much more demanding than for a vertical. Or conversely, if the only site around is the garage floor, try to build a vertical sensor. By way footnote: some have had success in siting instruments on an existing slab floor by sawing a square of it free from the surrounding floor. Large forces will still couple through the underlying clay, but some tilt noise is reduced. 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 From: Larry Cochrane Subject: New WinQuake beta release version 2.5.9 Date: Tue, 16 Feb 1999 00:28:13 -0800 Hi Everyone, I just released a new beta version of WinQuake. The version number is 2.5.9b. It can be downloaded using the following links: ftp://ftp.drnet.com/users/psn/software/wq259b_exe.zip ftp://ftp.drnet.com/users/psn/software/wq259b_full.zip or ftp://ftp.seismicnet.com/software/wq259b_exe.zip ftp://ftp.seismicnet.com/software/wq259b_full.zip The wq259b_full.zip file contains all of the files needed to update the current released WinQuake version. The wq259b_exe.zip file only contains the new exe file and one new data file. As with other beta release, you will need to unzip the file and copy all of the files over to your directory containing WinQuake. Make sure that you exit any running copies of WinQuake before copying the files. Heres what's new; Event File Integration: You can now double integrate an event file. This allows you to convert an event file recorded with an accelerometer too show displacement. ASCII Event File Format: In the last beta release I added the ability to save an event file in ASCII text. The new version can read in an event file in this text format. SEED/PEPP Mag Correction Number: Both SEED and PEPP volume / event files have sensor sensitivity information in the event file. I figured out how to use this information to come up with the equivalent magnitude correction number need by WinQuake to calculate Ms and Ml magnitudes. Some SEED volumes downloaded from dmc.iris.washington.edu are missing this information so I'm including a new data file called response.dat. WinQuake will search this file if the sensitivity information can't be found in the SEED volume. WinQuake will also search this file when reading an SAC binary event file. Old/New PSN format I simplified how WinQuake handles the old (type = 2) PSN event files. Before WinQuake kept track of the format and you could use the Modify dialog box to convert from the old to the new (type = 3) format. You could also, but I'm not sure why one would want too, convert from the new format to the old format. WinQuake now converts an old format event file to the new format when it reads it in. If you save the event file it will be in the new format. You can not convert a file from the new format to the old. Tables Dialog Box: The Tables dialog box has two new check boxes. If more then one event file window is opened, you can update all windows with the new depth, table to use and travel time table file name(S). The other check box allows you to automatically update the P and S location, if the event formation is present, after the Tables dialog box is closed. That's it. I'm running out of simple things to add to this release, so I'm going to try to finalize things and make an official release. If you have time I would appreciate it if you could try the new exe and let me know if you run into any problems. Regards, -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Re: Information about the seismograph Date: Tue, 16 Feb 1999 21:08:35 -0700 Edgard- The best place to find out about low-cost seismic instrumentation is the Public Seismic Network (PSN) at . -Edward Edgard Gonzales Zenteno wrote: > Dear Sir > I need information about your instrument and cost > > Please send me the information to: egz@............ > University of San Agustin , Arequipa Peru. -- Edward Cranswick US Geological Survey Golden, CO 80401 USA TEL: 303-273-8609 FAX: 303-273-8600 -------------------------------------------------------------- Pymatuning Earthquake Field Headquarters (1998 Sep 27 ... ) Cianci's Motel, 395 Mercer Rd (HWY#58), Greenville, PA 16125 TEL: 724-588-8550 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: New web page Date: Wed, 17 Feb 1999 21:51:05 -0800 Hi Everyone, The other day Tom Leiper sent me a letter describing how he and his daughter built a seismograph system for a school project. With his permission I converted the Word document to HTML and placed it on my web site. The link is http://www.seismicnet.com/leiper/seismograph.html. It has photos of their sensor and chart recorder they made. They got the system going just in time to capture the 7.3 Santa Cruz Island event that happened about two weeks ago. Chelsea is on the PSN list, so they will get any comments sent to the list. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Giovanni Rotta" Subject: COMPLIMENTS TO TOM AND CHELSEA FROM ITALIAN STATIONS Date: Thu, 18 Feb 1999 18:34:37 +0100 A warm welcome to Tom and Chelsea !! Have the best compliments for the beatutiful work from the Italian PSN stations ! Giovanni Rotta Giovanni Rotta Via F. Pizzigoni, 10 33010 Resia (Udine) I Lat. 46.373 N Long. 13.305 E rottag@.......... http://www.geocities.com/~resianet/ingssr.htm _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: More vert seis theory Date: Sat, 20 Feb 1999 10:57:05 -0500 Hi seismo designers, I finally got going with a first-cut on the analysis of vertical seismo geometry, comparing the LaCoste "zero-length" spring design to the leaf-spring design. Also posted an error correction on my previous leaf-spring analysis. New files: Word for Windows file. (let me know if you'd like this also in "PDF" form. The drawings came out quite a bit better in the ".doc" file) CAD files related to above update Corrected for error in "max stress" column To be found at: http://members.home.net/nordgren/public/ The web site has been on and off for the past couple of days. Think they're just upgrading, so keep trying if you don't get through the first time. Good luck, Brett Nordgren bnordgren@.............. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: chelsea@............ (Chelsea Leiper) Subject: Remote control programs Date: Sun, 21 Feb 1999 01:58:08 -0500 In reviewing the archives for this quarter I noticed some talk about remote control. I am in the business of manufacturing computerized medical diagnostic image display and capture systems and associated networking components. We have been performing remote control support and maintainence for over ten years on these systems. For DOS based systems I absolutely recommend the Norton Lambert "Close-Up" product which consists of two applications, "Support" which is the client and "Customer" which is the host. We use the RAS and DUN in Win95/98 along with custom applications which perform functions such as remote launching applications, displaying lists of running applications, killing applications and transferring files on the remote network, so we do not use the N-L product in these situations. Further, the versions of Close-Up since they added Windows were not as good as the original DOS product as the Windows GUI dramatically slowed things down, especially screen updates. But if you are doing DOS only on both sides, there is nothing better or faster. In particular, it has very nice "Automated Operations" functions that allow you to write a simple batch file to automatically connect up, send DOS commands (to either side) such as copying files and launching applications, and transfering files in both directions. We found that "PC Anywhere" had nowhere close to the capabilities in this area. In other words, you can (at the scheduled time) connect to the remote site, shutdown a running application, retrieve say, database files, launch a local application to process them, kill the local application, copy the processed files back to the remote location and re-start the remote application...as an example. It seems to me this would be perfect for a remote vacation home site running Emon, for instance. And that was the DOS version from ten years ago. Read about it at: http://www.nortonlambert.com/cupinfo2.htm Thanks for the compliments on Chelsea's seismo. Regards to all... Tom Leiper _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: RLLaney@....... Subject: WinQuake beta releases Date: Sun, 21 Feb 1999 13:49:22 EST Hi Larry: I have gone over WinQuake beta release versions 2.5.7, 2.5.8 and 2.5.9. As usual, I am impressed with what a great piece of software this is--and it gets better! In going over the changes, a couple of questions came to mind. Double integration--I understand how this is used to get displacement if one has an accelerometer, but does integrating data from a Lehman or SG sensor have any physical meaning? If I understand correctly, the output from the SG and the Lehman varies in proportion to the pendulum's velocity and is represented by counts. Single integrating some of my event records results in some interesting looking graphs, but does this give even relative displacement? Double integration of these records would seem to have no physical meaning. FFT--What is the relation of the "a" scale on the FFT plot to the counts on the event record? (By the way, the addition of the display of the frequency and period with the mouse location is a neat addition to the FFT window.) I assume that the "a" scale of the FFT plot is related to amplitude of the event record, but I had expected it to be derived from the log of the counts on the event record. But, the values on the "a" scale are greater than what would be calculated from the logs of the count values from the event record. Am I missing something here? Thanks for the WinQuake upgrades. Bob Laney _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "David A. Nelson" Subject: large pacific quake NOW!!!! Date: Mon, 22 Feb 1999 14:20:08 +1300 surface waves at 01:15 UTC monday 22 feb Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://www.seismicnet.com/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 From: Larry Cochrane Subject: Re: large pacific quake NOW!!!! Date: Sun, 21 Feb 1999 17:54:16 -0800 Using WinQuake's new event location feature I come up with the following numbers: Time of Origin: ~ 1:00:30 UTC Event Location: ~ -21.0 Lat. ~ 170.1 Long. Mag; ~ 6.7 Ms Too come up with these numbers I'm using several broadband sensors that I am monitoring over the Internet. See http://aslwww.cr.usgs.gov/Seismic_Data for more info. The stations I used where CTAO in Australia, TATO in Taiwan, KIP in Hawaii and BJT in China. It will be interesting to see how close I get to the numbers from NEIC. -Larry Cochrane Redwood City, PSN At 02:20 PM 2/22/99 +1300, you wrote: > > surface waves at 01:15 UTC monday 22 feb > > >Dave >Co-ordinator: >New Zealand >Public Seismic Network > Dave A. Nelson ZL4TBN > 24 Jensen St., > Green Is., Dunedin, > South Is.. New Zealand. > >http://www.seismicnet.com/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) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Charlie Plyler Subject: Re: large pacific quake NOW!!!! Date: Sun, 21 Feb 1999 21:08:31 -0500 Looks like you are very close Larry. 22Feb1999 01:00:48.4 13.7S 166.9E 33 mb=5.8 A*NOR VANUATU ISLANDS 0132 22Feb1999`01:19' A SED PKP AZ= 71 SL=2.844 0126 22Feb1999 01:00:38.1 20.3S 169.9E 33 mb=5.7 A*NEI VANUATU ISLANDS 0120 Radius: 399 km Charlie Plyler Larry Cochrane wrote: > > Using WinQuake's new event location feature I come up with the following > numbers: > Time of Origin: ~ 1:00:30 UTC > Event Location: ~ -21.0 Lat. > ~ 170.1 Long. > Mag; ~ 6.7 Ms > > Too come up with these numbers I'm using several broadband sensors that I > am monitoring over the Internet. See http://aslwww.cr.usgs.gov/Seismic_Data > for more info. The stations I used where CTAO in Australia, TATO in Taiwan, > KIP in Hawaii and BJT in China. > > It will be interesting to see how close I get to the numbers from NEIC. > > -Larry Cochrane > Redwood City, PSN > > At 02:20 PM 2/22/99 +1300, you wrote: > > > > surface waves at 01:15 UTC monday 22 feb > > > > > >Dave > >Co-ordinator: > >New Zealand > >Public Seismic Network > > Dave A. Nelson ZL4TBN > > 24 Jensen St., > > Green Is., Dunedin, > > South Is.. New Zealand. > > > >http://www.seismicnet.com/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) > > 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 From: "J. D. Cooley" Subject: Re: large pacific quake NOW!!!! Date: Sun, 21 Feb 1999 20:31:37 -0800 Wow! Someday I will get Windows 95/98 so I can do that!! VERY close, Larry. 99/02/22 01:00:32 21.52S 169.66E 33.0 6.4Ms A LOYALTY ISLANDS REGION At 05:54 PM 2/21/99 -0800, Larry Cochrane wrote: >Using WinQuake's new event location feature I come up with the following >numbers: > Time of Origin: ~ 1:00:30 UTC > Event Location: ~ -21.0 Lat. > ~ 170.1 Long. > Mag; ~ 6.7 Ms > >Too come up with these numbers I'm using several broadband sensors that I >am monitoring over the Internet. See http://aslwww.cr.usgs.gov/Seismic_Data >for more info. The stations I used where CTAO in Australia, TATO in Taiwan, >KIP in Hawaii and BJT in China. > >It will be interesting to see how close I get to the numbers from NEIC. > >-Larry Cochrane >Redwood City, PSN > > >At 02:20 PM 2/22/99 +1300, you wrote: >> >> surface waves at 01:15 UTC monday 22 feb >> >> >>Dave >>Co-ordinator: >>New Zealand >>Public Seismic Network >> Dave A. Nelson ZL4TBN >> 24 Jensen St., >> Green Is., Dunedin, >> South Is.. New Zealand. >> >>http://www.seismicnet.com/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) > >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 From: Larry Cochrane Subject: Re: large pacific quake NOW!!!! Date: Mon, 22 Feb 1999 14:36:55 -0800 Well it looks like I was off by around 2 seconds for the time of origin, 75km for the Lat / Long and .3 Ms. Not bad for non-government work.... -Larry At 08:31 PM 2/21/99 -0800, J. D. Cooley wrote: >Wow! Someday I will get Windows 95/98 so I can do that!! VERY close, Larry. > >99/02/22 01:00:32 21.52S 169.66E 33.0 6.4Ms A LOYALTY ISLANDS REGION > >At 05:54 PM 2/21/99 -0800, Larry Cochrane wrote: >>Using WinQuake's new event location feature I come up with the following >>numbers: >> Time of Origin: ~ 1:00:30 UTC >> Event Location: ~ -21.0 Lat. >> ~ 170.1 Long. >> Mag; ~ 6.7 Ms >> >>Too come up with these numbers I'm using several broadband sensors that I >>am monitoring over the Internet. See http://aslwww.cr.usgs.gov/Seismic_Data >>for more info. The stations I used where CTAO in Australia, TATO in Taiwan, >>KIP in Hawaii and BJT in China. >> >>It will be interesting to see how close I get to the numbers from NEIC. >> >>-Larry Cochrane >>Redwood City, PSN > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Re: large pacific quake NOW!!!! Date: Mon, 22 Feb 1999 17:49:02 -0700 Larry- Amazing!!! -Edward Charlie Plyler wrote: > Looks like you are very close Larry. > > 22Feb1999 01:00:48.4 13.7S 166.9E 33 mb=5.8 A*NOR VANUATU > ISLANDS 0132 > 22Feb1999`01:19' A SED PKP AZ= 71 > SL=2.844 0126 > 22Feb1999 01:00:38.1 20.3S 169.9E 33 mb=5.7 A*NEI VANUATU > ISLANDS 0120 > Radius: 399 km > Charlie Plyler > > Larry Cochrane wrote: > > > > Using WinQuake's new event location feature I come up with the following > > numbers: > > Time of Origin: ~ 1:00:30 UTC > > Event Location: ~ -21.0 Lat. > > ~ 170.1 Long. > > Mag; ~ 6.7 Ms > > > > Too come up with these numbers I'm using several broadband sensors that I > > am monitoring over the Internet. See http://aslwww.cr.usgs.gov/Seismic_Data > > for more info. The stations I used where CTAO in Australia, TATO in Taiwan, > > KIP in Hawaii and BJT in China. > > > > It will be interesting to see how close I get to the numbers from NEIC. > > > > -Larry Cochrane > > Redwood City, PSN > > > > At 02:20 PM 2/22/99 +1300, you wrote: > > > > > > surface waves at 01:15 UTC monday 22 feb > > > > > > > > >Dave > > >Co-ordinator: > > >New Zealand > > >Public Seismic Network > > > Dave A. Nelson ZL4TBN > > > 24 Jensen St., > > > Green Is., Dunedin, > > > South Is.. New Zealand. > > > > > >http://www.seismicnet.com/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) > > > > To leave this list email listserver@.............. with the body of the > > message: leave PSN-L > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Edward Cranswick US Geological Survey Golden, CO 80401 USA TEL: 303-273-8609 FAX: 303-273-8600 -------------------------------------------------------------- Pymatuning Earthquake Field Headquarters (1998 Sep 27 ... ) Cianci's Motel, 395 Mercer Rd (HWY#58), Greenville, PA 16125 TEL: 724-588-8550 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Bonnie Schafer" Subject: Fw: {EarthWaves} "CYBERSYSTEM" FOR EARTHQUAKE ENGINEERING SIMULATION Date: Tue, 23 Feb 1999 19:26:40 -0800 Bonnie the crafty crafter -----Original Message----- > >Embargoed until 2:00 P.M., ESTMedia contact: February 23, 1999 >Joel Blumenthal NSF PR 99-13 >(703) 306-1070/jblument@.............. contact:Priscilla Nelson >(703) 306-1361/pnelson@....... > > NSF TO ESTABLISH "CYBERSYSTEM" > FOR EARTHQUAKE ENGINEERING SIMULATION > > A top National Science Foundation [NSF] official today described >to a House >subcommittee how the NSF plans to use information technology [IT] to >establish a >cyber Network for Earthquake Engineering Simulation [NEES]. > Testifying before the House Committee on Science' Subcommittee on >Basic >Research, Joseph Bordogna, NSF acting deputy director, said that NEES >"will >change the face of earthquake engineering." His statement was part of >testimony in favor of re-authorizing the National Earthquake Hazards >Reduction >Program [NEHRP]. > NEES "will use IT to serve a critical national need (reducing and >mitigating effects of earthquakes): to help save lives and money; and >to make more >efficient use of government's investment in science and engineering," >Bordogna said. >NSF is seeking $7.7 million in its fiscal 2000 budget request for the >first year of aplanned five-year, $81.9 million program for NEES. >Bordogna told the subcommittee, chaired by Rep. Nick Smith (R-Mich.), >that NEES, like NEHRP, was initiated in response to a mandate from >Congress to take >stock of the nation's experimental and testing capability in >earthquake >engineering. > NEES will use a computer network to bring "a complete collection >of >state-of-the-art facilities under one `virtual roof,'" Eugene Wong, >NSF's assistant director >for engineering, said. "It will provide remote access to users, and >make a >complete system of testing and experimental facilities available to >the entire >earthquake engineering community." Networking software will enable the >system >to use models and databases to develop model-based simulation, Wong >added. >More than 30 U.S. institutions currently have some kind of >experimental >earthquake engineering facilities. These include shake tables for >earthquake >simulations, reaction walls for pseudodynamic testing, geotechnical >centrifuges >for testing soils during earthquakes, and floor reaction systems. >NEES funds would be used to: create new shake tables and upgrade >existing >shaketables; build centrifuges and Tsunami testing tanks; build new >reaction walls, >load simulators and response modifiers; and create field test >facilities (i.e. mobile >equipment, field sites and post-quake labs). Funds will also provide >for system >integration and to ensure completion of all corefacilities. Bordogna >stated that NEES >can serve as an educational tool for students and the public, and as >the primary >repository of earthquake engineering physical experiments and data. He >added that >NEES also will leverage public and private investments in the $100 >billion-a-year IT >industry by using existing software and making effective use of the >high-speed >networking infrastructure that is one of NSF's most successful >ventures. > -NSF- > > >^^ To UNSUBSCRIBE: Send "unsubscribe earthwaves" to majordomo@........... >^^ To SUBSCRIBE: Send "subscribe earthwaves" to majordomo@........... >^^ To SUBSCRIBE ANOTHER: Type "subscribe earthwaves name@........." >^^ All commands should be placed in body of message, with no quotes >^^ Auto-approval occurs when confirmation email is returned by subscriber >^^ Check current EQ reports: http://www.earthwaves.com/current.html > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Malcolm Purves Subject: Re: Fw: {EarthWaves} "CYBERSYSTEM" FOR EARTHQUAKE ENGINEERING SIMULATION Date: Wed, 24 Feb 1999 05:24:21 +0000 Errr, pardon me, but would you care to edit that so as we can see the meaning of it, please ? or paraphrase perhaps. or did you send it tongue-in-whatsit ? Malcolm. Bonnie Schafer wrote: > > Bonnie the crafty crafter > -----Original Message----- > > > >Embargoed until 2:00 P.M., ESTMedia contact: February 23, 1999 > >Joel Blumenthal NSF PR 99-13 > >(703) 306-1070/jblument@.............. contact:Priscilla Nelson > >(703) 306-1361/pnelson@....... > > > > NSF TO ESTABLISH "CYBERSYSTEM" > > FOR EARTHQUAKE ENGINEERING SIMULATION > > > > A top National Science Foundation [NSF] official today described > >to a House Big Snip _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Bonnie Schafer" Subject: Re: Fw: {EarthWaves} "CYBERSYSTEM" FOR EARTHQUAKE ENGINEERING SIMULATION Date: Wed, 24 Feb 1999 21:59:23 -0800 Hi, I sent it tongue and cheek--so to speak--just thought it would be of interest. 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 From: "Walt Williams" Subject: PSN-L: {EarthWaves} a comment Date: Thu, 25 Feb 1999 01:55:13 -0800 Hello Bonnie, I liked it. Walt Williams, 99.02.25 OSR ================================== ------- Forwarded Message Follows ------- Reply-to: PSN-L Mailing List From: "Bonnie Schafer" To: "PSN-L Mailing List" Subject: Re: Fw: {EarthWaves} "CYBERSYSTEM" FOR EARTHQUAKE ENGINEERING SIMULATION Date: Wed, 24 Feb 1999 21:59:23 -0800 Hi, I sent it tongue and cheek--so to speak--just thought it would be of interest. 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 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Re: I need to know about.... Date: Thu, 25 Feb 1999 10:16:25 -0700 Rani- > How many seismographs are needed in each location (presumably of an > earthquake struck region) to gain sufficient info? The short answer to your question is: If one wants to understand how earthquakes damage buildings, and if a building on one side of the street collapsed but a building on the other side of the street did not collapse, there need to be strong motion recordings from both sides of the street, i.e., there should at least be a seismograph in every structure at risk. I also have longer answers to your question. If you need more information, please let me know. Have you seen the Public Seismic Network, for example, ? -Edward rani ramanathan wrote: > I was wondering if you could help me on this question: > How many seismographs are needed in each location(presumably of an > earthquake struck region) to gain sufficient info?I would really > appreciate it if you would be able to help me on this question. > Thanking you,Aashlesha V. -- 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 From: Brett Nordgren Subject: DXF Request to S-T M Date: Thu, 25 Feb 1999 13:25:39 -0500 Sean-Thomas, I'm making slow progress on the math to predict a leaf-spring vertical's free period, based on the spring dimensions and the system geometry. I'm hoping to possibly get some clues as to how to go about setting up the geometry for infinite (or very long) free period. Using some "pretend" numbers, I was able to cobble up a design that predicts zero net restoring force at its operating point, but I am still suspicious that there are errors in my method. So now I'd like to see if theory and practice can be made to agree (and if not, why not). Do you have any sort of .DXF file of a configuration for which you have measured the free period? I would scale off the dimensions (AutoSketch 5), use them and the mass value to compute a period and then see if the calculation bears any relation to the actual performance. One thing that might be coming out of this is that there may possibly not be any great advantage to tilting the spring force line back toward the support like LaCoste. But I need to look at the numbers a whole lot more before I'd ever want to state that for certain. Many thanks, Brett _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Francesco Subject: LARGE QUAKE: RUSSIA Date: Thu, 25 Feb 1999 22:09:13 +0100 Org time: 18:58:34 Ms 6.1 Loc.: Lake Baikal Region - Russia I.E.SN. PSN ITALY _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: leaf spring and period Date: Fri, 26 Feb 1999 00:40:39 -0600 (CST) Brett, The drawing of the seismometer on the web site at: http://www.eas.slu.edu/People/STMorrissey/ stmfigs.html" The STM-8 Seis: Figures, Schematics, Drawings shows the current configuration and dimensions of the leaf spring vertical. It clearly shows the relative positions of the spring supports. As the upper support of the spring is moved toward the hinges, the period approaches instability. Small adjustments of a few mm back away from the hinge will result in stable periods of 20 seconds or more. At this point the relative stiffness of the hinges themselves becomes a consideration, but I have no estimate of the force they contribute. But the mechanical period is not a major concern for the VBB instrument, since it only affects the damping term. Longer mechanical periods only enhance the thermal instability. I am currently operating the Beta unit at 8 seconds. But any desired instrument performance is possible even with a moderate (and stable) mechanical period. By setting the feedback capacitor Cp at 20 ufarad, the operational damping at 0.707, and the displacement gain r at 10^6, all of which keep the output level constant, I can set the operating period To anywhere from 1 second to 960 seconds by simply selecting the integrator period TI and calculating the required value for the proportional resistor Rp and the integral resistor RI. (At 960 seconds these values exceed 6 megohms with a 120 second integrator). A 3-pole switch can select the values. This provides a handy feature in that a 1-second response is very useful for making adjustments, and being able to select an intermediate period for some circumstances like during windy periods can be advantageous. Some commercial VBBs use a relay to change these values to temporarily configure a 1-second response during the operation of the centering motor. I don't want to discourage you from your curiosity about the leaf spring behavior. But the beauty of the triple feedback VBB is that a long mechanical period is not an important concern as long as it is stable. 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 From: "Bonnie Schafer" Subject: Re: PSN-L: {EarthWaves} a comment Date: Fri, 26 Feb 1999 22:37:59 -0800 Hi, thanks glad you did. 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 From: Steve Hammond Subject: [Fwd: QED NUMBER 9-057] Date: Sat, 27 Feb 1999 17:17:00 -0800 QEDPOST - earthquake alert list some of you may have not received this or known about it. Regards, Steve Hammond From: Steve Hammond Subject: [Fwd: EQ MAG 5.8 LAKE BAYKAL REGION, RUSSIA] Date: Sat, 27 Feb 1999 17:18:40 -0800 BIGQUAKE information Also, some of you may not have received this or known about it. Regards, Steve Hammond From: S-T Morrissey Subject: BIGQUAKE listing Date: Sat, 27 Feb 1999 13:32:59 -0600 (CST) Re. BIGQUAKE mailing from NEIS. Thanks to Steve for informing the PSN re the Bigquake update. In reviewing the latest event, it comes to mind that maybe, someday, over-the-rainbow, etc., PSN station data will be used in real time by NEIS for event location via some automatic retrieval setup. I am always pleased when the St. Louis Univ. "Billiken" network of VBB stations is fully used: (in the Lake Baykal event: JFWS,CBKS,CCM,WCI,WVT,MIAR were used). It would definitely give satisfaction to a PSN station operator to see their data used. On the other hand, the Mb. 3.8 Main event had somewhat poor coverage, which is where the PSN may eventually be able to make a significant contribution. Realizing a near real-time response would be a major challenge. 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 From: Greg Subject: Linux people? Date: Sat, 27 Feb 1999 20:05:47 +0000 If there are any Linux people on the PSN list you might be interested in this. I have been attempting(!) to write a device driver for Larry's ADC board for a while. I'm really not a really good programmer so it's very difficult. If anyone wants to help out that would be great. Why would you want to use Linux instead of DOS? Tons of networking options. You could set it up so that it automatically ftps your event files to your web site every time it records one or just set it up as a full time ftp server on the internet. There's so many possibilities... I talked with another guy about this and he suggested Real time Linux could increase the sampling rate a LOT. I'm using regular non-Real time Linux to write it. I found a development kit for it which makes it almost possible for me to understand. I also have the book Linux Device Drivers. They both concentrate on generating modules so I don't think they'd work in a monolithic kernel? I tested the sample modules for LDDK and it works as far as I can tell. I have a /dev/adc file now. I don't think LDDK support interrupts, but the book does explain them in almost excessive detail. There are tons of other ADC drivers to look at and that might be my next step. I'm missing some example code of how to talk to the driver. I can cat /dev/adc or echo "" > /dev/adc, but I don't know how to call a function inside the driver from a C program. I just thought there might be some interest, Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Walt Williams" Subject: PSN-L: Linux people? Date: Sat, 27 Feb 1999 18:17:37 -0800 Hi Greg, Couple months back the Linux Journal published an informative article about writing device drivers in......LINUX! :)) Check it out. Walt Williams, 99.02.27 OSR p.s. Did I ever say thanks for the PCB program advice you gave me? (it was good advice, and solved the problem, thank you :) ========================================== ------- Forwarded Message Follows ------- Date: Sat, 27 Feb 1999 20:05:47 +0000 From: Greg To: "psn-l@.............." Subject: Linux people? Reply-to: PSN-L Mailing List If there are any Linux people on the PSN list you might be interested in this. I have been attempting(!) to write a device driver for Larry's ADC board for a while. I'm really not a really good programmer so it's very difficult. If anyone wants to help out that would be great. Why would you want to use Linux instead of DOS? Tons of networking options. You could set it up so that it automatically ftps your event files to your web site every time it records one or just set it up as a full time ftp server on the internet. There's so many possibilities... I talked with another guy about this and he suggested Real time Linux could increase the sampling rate a LOT. I'm using regular non-Real time Linux to write it. I found a development kit for it which makes it almost possible for me to understand. I also have the book Linux Device Drivers. They both concentrate on generating modules so I don't think they'd work in a monolithic kernel? I tested the sample modules for LDDK and it works as far as I can tell. I have a /dev/adc file now. I don't think LDDK support interrupts, but the book does explain them in almost excessive detail. There are tons of other ADC drivers to look at and that might be my next step. I'm missing some example code of how to talk to the driver. I can cat /dev/adc or echo "" > /dev/adc, but I don't know how to call a function inside the driver from a C program. I just thought there might be some interest, Greg _________________________________________________________________ ____ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: Re: leaf spring and period Date: Sat, 27 Feb 1999 22:31:09 -0500 Sean-Thomas, Many thanks for your update on the design. Indeed, I was using your "Vertseis" gif's to get the dimensions. As a test, I had been calculating the mass needed for equilibrium, and was getting values about fifteen percent low. Thought the problem was either with my math or with the beam dimensions I was entering. But, once I made the spring 3.5" wide (instead of 3") the mass required came out within 1/2% of 0.5 kg, so now I'm really hopeful that was the answer. Indeed, I agree, the beam free oscillation characteristics have virtually no effect on the velocity response with the feedback turned on. I was more interested in the benefits from getting the net restoring force down. As it stands, at DC, with +/- 9 V out of Op Amp A4 through 107k Ri in parallel with 581k Rp, there are available somewhere around +/- 100 microamps to the feedback coil; less with higher resistance values. Times 13 N/A that's roughly +/- 130 dynes force available at DC. With no help from the geometry (3.9 sec period), for +/- 1mm at the mass I think you would need something in the range of +/- 260 dynes to staticaly control the beam at its extremes, just to overcome the effective spring constant. A 20 sec period gets you down to about 4.9 dynes / mm, which is now well within the available feedback force at DC. By carefully tweaking the geometry on the computer (probably way better than one could do in practice) I can compute a net beam restoring force of about 0.2 dynes / mm (100 sec?). Even with a more realizable level of tuning, the feedback should still easily be able to control the beam at 0 Hz over the full range of motion. Also, reducing the effective spring constant should significantly increase the loop gain at DC and at the very low frequencies where it is needed, while avoiding any effects at the higher frequencies that might start loop oscillations. I don't think this helps in the slightest with spring creep or thermal variations, but I'm also almost certain that it won't hurt, either. Again, thanks for your comments. Brett At 12:40 AM 2/26/99 -0600, you wrote: >Brett, >The drawing of the seismometer on the web site at: > >http://www.eas.slu.edu/People/STMorrissey/ >stmfigs.html" The STM-8 Seis: Figures, Schematics, Drawings > >shows the current configuration and dimensions of the leaf spring >vertical. It clearly shows the relative positions of the spring >supports. As the upper support of the spring is moved toward the hinges, >the period approaches instability. Small adjustments of a few >mm back away from the hinge will result in stable periods of >20 seconds or more. At this point the relative stiffness of the >hinges themselves becomes a consideration, but I have no estimate >of the force they contribute. > >But the mechanical period is not a major concern for the VBB >instrument, since it only affects the damping term. Longer mechanical >periods only enhance the thermal instability. I am currently operating >the Beta unit at 8 seconds. > >But any desired instrument performance is possible even with a moderate >(and stable) mechanical period. By setting the feedback capacitor Cp at >20 ufarad, the operational damping at 0.707, and the displacement gain >r at 10^6, all of which keep the output level constant, I can set the >operating period To anywhere from 1 second to 960 seconds by simply >selecting the integrator period TI and calculating the required value >for the proportional resistor Rp and the integral resistor RI. (At 960 >seconds these values exceed 6 megohms with a 120 second integrator). >A 3-pole switch can select the values. This provides a handy feature in >that a 1-second response is very useful for making adjustments, and being >able to select an intermediate period for some circumstances like >during windy periods can be advantageous. Some commercial VBBs use >a relay to change these values to temporarily configure a 1-second >response during the operation of the centering motor. > >I don't want to discourage you from your curiosity about the leaf spring >behavior. But the beauty of the triple feedback VBB is that a long >mechanical period is not an important concern as long as it is stable. > >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) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Greg Subject: Re: PSN-L: Linux people? Date: Sun, 28 Feb 1999 06:42:36 +0000 Walt Williams wrote: Hey-low, > Couple months back the Linux Journal published an informative > article about writing device drivers in......LINUX! :)) I've been reading it for about a year now. I subscribe. I don't remember seeing the article, but maybe I wasn't looking for it or I skipped the article. I'll have to dig through the old issues. > p.s. > Did I ever say thanks for the PCB program advice you gave me? > (it was good advice, and solved the problem, thank you :) I doubt it was me that gave the advice. However it's not unlike me to talk over my own head. I only played with the one program. I forget the name of it. It was for Windows 95. The program was free, but the only way to get a PCB out it was to send it to the company that wrote the software. James wrote: > might try here > http://www.slashdot.org/ I read it almost every day. Usually twice. A lot of the articles are just links to other news sites. > or maybe a user group is close to you > http://www.linux.org/users/groups/usa/index.html I was one of the first members of the local group. My ISP is the server for the mailing list. I never went to a meeting, but I doubt it would help. Tucson is a almost a technological vaccum. ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: Hinge effects Date: Sun, 28 Feb 1999 12:31:09 -0500 Sean-Thomas, You were questioning the effect of the beam hinges on the leaf-spring vertical, so last night I took a look at what their effect might be. To date, I've been ignoring the effect of the hinges. I think the effective spring constant at the mass, due to the hinges is given by K = (E W t^3) /(12 b^2 L) lb/in (x 17,638 to get dynes / mm) E is the elastic modulus of spring bronze = 1.5E7 lb/in^2 T is the leaf thickness = 0.005 in W is the total width of all leaves = 4 x 3/8 = 1.5 in b is the distance from the hinge to the mass, assumed here = 14.72 in L is the free-air length of the leaves. (big assumption) = .04 in L is the hardest to know. It depends mainly on how much the outside corners of the angles that support the leaves have been rounded off. You might get a rough idea by measuring the gap between the angles at a 45 degree angle with a feeler gauge and then multiplying by the square-root of 2. Multiplying the numbers out gives 477 dynes / mm, I think. Much stiffer than I'd expected! The natural period would = sqrt(1974 / k) or about 2 sec in this example. That's the effect of the hinges alone. Since k is proportional to 1 / t^3, using thinner material should lower k enormously. However, with thinner material, I'd start to think about possible buckling of the horizontal hinges, since the force on the beam hinge is up and to the left in your drawing. If you wanted to not worry about that, you might try a right-left mirror image on the hinge support angles and move the vertical support column 1.5 in to the right. That way, the horizontal leaves would be in tension. Even .001" shim stock should be strong enough. 5 lb force / (0.75 in x .001) is under 7000 psi. Comfortable, though you wouldn't want to bang it around too hard. I'm pretty sure that the hinge effect can also be compensated out by the geometry, but I suspect that having a low spring constant to begin with is even better. Regards, Brett _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: RLLaney@....... Subject: Undocumented event?? Date: Sun, 28 Feb 1999 15:16:03 EST I recorded an event on 2/27/99 at 17:17:42 UTC, or at least it appeared to be an event. The "P" arrival was definitely above the noise and the "S" arrival was very strong. The estimated distance to the "event" was about 300 km. Sometimes surface waves from distant quakes can appear as something more local, but there were no large distant events reasonably prior to this time. Any suggestions from anyone? Thanks. Bob Laney Herndon, VA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "J. D. Cooley" Subject: Re: Undocumented event?? Date: Sun, 28 Feb 1999 14:21:02 -0800 I noticed this on the global seismograms and was waiting for an ageny to report it, but no luck. The International Data Center has the following info: 1999/02/27 07:13:49.8 62.78S 169.50E mb 4.2 Balleny Islands Region I have a nice seismogram from New Zealand I can e-mail to anyone that would like it. And, thank you Bob for including the date and time in UTC. "JD" At 03:16 PM 2/28/99 EST, Bob Laney wrote: >I recorded an event on 2/27/99 at 17:17:42 UTC, or at least it appeared to be >an event. The "P" arrival was definitely above the noise and the "S" arrival >was very strong. The estimated distance to the "event" was about 300 km. >Sometimes surface waves from distant quakes can appear as something more >local, but there were no large distant events reasonably prior to this time. >Any suggestions from anyone? > >Thanks. > >Bob Laney >Herndon, VA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Xmas in Dominica: EQs, Volcanoes, and the PSN Date: Sun, 28 Feb 1999 19:34:52 -0700 Jody Bourgeois* and Edward Cranswick will present a talk: "Xmas in Dominica: Earthquakes, Volcanoes, and the Public Seismic Network" on Tuesday, 2 March 1999, at 1:00 PM, in the 3rd Floor Conference Room (Room 318), USGS Golden. *visiting scientist from the University of Washington -- 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 From: "David A. Nelson" Subject: Re: Undocumented event?? Date: Mon, 1 Mar 1999 15:40:22 +1300 At 14:21 28/02/99 -0800, you wrote: >I noticed this on the global seismograms and was waiting for an ageny to >report >it, but no luck. The International Data Center has the following info: >1999/02/27 07:13:49.8 62.78S 169.50E mb 4.2 Balleny Islands Region >I have a nice seismogram from New Zealand I can e-mail to anyone that would >like it. >"JD" yes please would appreciate a copy Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://www.seismicnet.com/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 From: Larry Cochrane Subject: Lehman pickup coil and magnet. Date: Sun, 28 Feb 1999 21:09:52 -0800 Hi Everyone, I'm looking for some advice on a replacement for the pickup coil I have been selling. As some of you know I have been selling a coil and magnet combination to help people build their sensor without having to worry about winding a coil. I have a picture of the coil and magnet at http://psn.quake.net/coilmag.html. The problem is I can no longer find the relay I have been using for the coil. While the relays I have been using are new, I have been getting them from a local surplus electronics store. Well I went to the well, so too speak, one too many times and they no longer have the part. The insignia on the relay looks like they where made by Grayhill. Grayhill no longer makes electromechanical relays so I can buy them from a normal distributor. The nice thing about the old 220vac relay coil was it had a lot of turns, over 10k with a dc resistance around 8 to 9k, and fit nicely within the 22 lb horseshoe magnet. I have looked at some other high voltage high resistance relays, but they have a much smaller coil. This produces a much smaller output when placed on my Lehman using the existing 22 lb magnet. I was wondering if anyone had any ideas on what I could offer as a coil / magnet combination. Something I can get off the shelf. I may have too check into having a coil winding shop make some for me. The problem maybe getting a suitable bobbin for them to wind the coil on. With the low quantity order like mine, cost per coil maybe a problem. I was getting the relays for under $5.00... -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Mark Robinson" Subject: Re: Lehman pickup coil and magnet. Date: Mon, 1 Mar 1999 18:40:43 +1300 Hi Larry Try looking at coils for electrical contactors from an electrical wholesaler (or whatever you have over there). regards Mark -----Original Message----- From: Larry Cochrane To: psn-l@.............. Date: Monday, 1 March 1999 18:30 Subject: Lehman pickup coil and magnet. >Hi Everyone, > >I'm looking for some advice on a replacement for the pickup coil I have >been selling. As some of you know I have been selling a coil and magnet >combination to help people build their sensor without having to worry about >winding a coil. I have a picture of the coil and magnet at >http://psn.quake.net/coilmag.html. > >The problem is I can no longer find the relay I have been using for the >coil. While the relays I have been using are new, I have been getting them >from a local surplus electronics store. Well I went to the well, so too >speak, one too many times and they no longer have the part. The insignia on >the relay looks like they where made by Grayhill. Grayhill no longer makes >electromechanical relays so I can buy them from a normal distributor. > >The nice thing about the old 220vac relay coil was it had a lot of turns, >over 10k with a dc resistance around 8 to 9k, and fit nicely within the 22 >lb horseshoe magnet. I have looked at some other high voltage high >resistance relays, but they have a much smaller coil. This produces a much >smaller output when placed on my Lehman using the existing 22 lb magnet. > >I was wondering if anyone had any ideas on what I could offer as a coil / >magnet combination. Something I can get off the shelf. I may have too check >into having a coil winding shop make some for me. The problem maybe getting >a suitable bobbin for them to wind the coil on. With the low quantity order >like mine, cost per coil maybe a problem. I was getting the relays for >under $5.00... > >-Larry Cochrane >Redwood City, PSN > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Re: WinQuake beta releases - FFT Date: Mon, 01 Mar 1999 00:07:22 -0800 At 01:49 PM 2/21/99 EST, RLLaney@....... wrote: [snip] >FFT--What is the relation of the "a" scale on the FFT plot to the counts on >the event record? (By the way, the addition of the display of the frequency >and period with the mouse location is a neat addition to the FFT window.) I >assume that the "a" scale of the FFT plot is related to amplitude of the event >record, but I had expected it to be derived from the log of the counts on the >event record. But, the values on the "a" scale are greater than what would be >calculated from the logs of the count values from the event record. Am I >missing something here? I'm not 100% sure what the "a" scale represents when doing an FFT. If you do an FFT of a pure sine wave you get about 1/2 of the input A/D counts. The Log display displays the same data as the linear display, only in a different scale. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Thomas W Leiper Subject: Re: Larry's SOS call for pickup coil Date: Mon, 1 Mar 1999 04:17:06 -0500 Larry - I was thinking about making one using a Teflon tape pipe sealant dispenser with snap-on cover. The core would make a good bobbin, and you could snap the cover back on when done. It also has a decent diameter so the counter-emf problem I mentioned in Chelsea's seismo article would be reduced. You could also use small cylindrical magnets in the solenoid configuration. It would be no big deal to rig up a DC motor and mandrel for a winding rig. In fact you could just take the motor and foot pedal off an old sewing machine (who uses THEM anymore!), and have a machine shop (or me) turn down a mandrel for you in about 5 minutes. Just give me the motor shaft dimensions and the ID & width of the tape core you select, and I'll make you one because I'm a nice guy. Then, if you really wanted to sell a high quality coil, you could separate the winding layers with the Teflon tape you would otherwise throw out, although the first roll would probably be enough Teflon until you retire. The ones I have, have great dimensions. The "bobbin" ID (size of the hole) is 1". The OD is 2" and the width is 5/8". The plastic thickness is about 1/16", so the ID of the windings would be 1 1/8" and the width 1/2". Same OD. I am SURE that Sean can respond in less than a nanosecond with the formula for calculating the number and resistance of turns by wire gauge (domestic and foreign) for sixteen different winding tensions, including tapered tension reduction rates, which would reduce compression and distortion of the inner windings...Sean? On another note, for those who do not have the right kind of hailer on their boat to make the pickup I described on Chelsea's seismo, I have found a cheap and available substitute which works just as well. Use a magnet-mount base for a CB/Ham mobile antenna. Turn the iron bar so that its diameter halves the distance between the ID and the OD of the circular magnet in the mount. You can put an inner "shoulder" on it that is the ID of the magnet so it stays centered. It won't go anywhere. After removing the antenna mount and bolt from the plate, you can put in a 3/8" X 4 carriage bolt sticking out the other side to go through the boom, a locknut, and into a counterweight. Adios... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Ken Navarre Subject: Re: Larry's SOS call for pickup coil Date: Mon, 1 Mar 1999 08:30:11 -0800 (PST) On Mon, 1 Mar 1999, Thomas W Leiper wrote: > Larry - I was thinking about making one using a Teflon tape pipe sealant > dispenser with snap-on cover. (snip) > You could also use small cylindrical magnets in the solenoid > configuration. Hummm, now that I think about it this seems like a really good solution for us to wind our own solenoids! I picked up a few "cow magnets" from a local feed store that would fit nicely into the core. Cow magnets are shoved down a cow's gullet so that they will snatch onto any metal wire that the cow eats as it meanders along in it's profession of making methane... Ken _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Nick & Sophie Caporossi Subject: SOS call for pickup Coils Date: Mon, 01 Mar 1999 13:17:31 -0500 Hi Thomas and Larry: Teflon tape pipe sealant dispenser is a good idea. I have made a few coils by using the dispenser from one pound lead that is used by plumbers. I cut a portion from the center and glue the sides together. The ID is about 1 inch and the OD is about 2 and 1/8 inches. I've used a fishing spinner to wind the coil. The bobbin puts about 20 turns across the reel. It goes very fast with a little care you can put on about 500 turn a minute. On the question of magnets, AC Hardware sells horse shoe magnets, they are a little small, about 20 pound pull. For that size magnet they run about $7.00. Has any one used a flat magnet. Some of them are quite strong, and easy to come by. Nick _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Ian Smith Subject: Re: SOS call for pickup Coils Date: Mon, 01 Mar 1999 08:36:12 -1000 I got a rare earth magnet from http://www.sciplus.com/cgi-bin/basket/920313088.27/home.html V strong, though irregular in shape, a bit like a stone. It might just fit inside a 1 inch ID former. They also have loads of other "interesting" items. I Smith _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: coil.info Date: Mon, 1 Mar 1999 13:45:35 -0600 (CST) Thomas, Yes, I have been winding coils for many years, including making large quadrupole focusing magnets for the cyclotron some 30 years ago. For these, every bend of every turn had to be exactly positioned, and the resistance of the #10 wire of each pole had to come out identical. Since you asked, there is an appendix in the Riedesel paper... "Limits of Sensitivity of Inertial Seismometers with Velocity Transducers and Electronic Amplifiers", by Mark A. Riedesel, Robert D. Moore, and John A. Orcutt; Bulletin of the Seismological Society of America, Vol. 80, No 6, December 1990. .... that has all the parameters of seismometer coils explained; (the main conclusion is that the generator constant increases only with the square root of the coil resistance, everything else being equal). Also, there is considerable info in "Reference Data for Radio Engineers", whatever edition you have, on coils and magnets. By the way though, my interest in VBB sensors precludes the need for high resistance coils, which don't work in the transfer function. The coil and magnet of a 10" speaker works just fine if the boom is long enough to allow the arc of the coil movement to not jam in the magnet. The generator constant of this 8-ohm coil is about 12 N/A (Newtons/Ampere) or Volts/meter/second. A large 500-ohm coil (from the S-5100 long-period seismometer), has a constant of 96 N/A in the 3"dia x 4" long annular magnet. The output difference of X 8 is easily made up for with a quiet amplifier, like the OP-27. And for one who uses "THEM" sewing machines anymore, the one at the back of the electronics desk here still keeps the socks darned and the jeans sewed up, if I can find it among the parts and assemblies of various seismometer configurations. Its bobbin winder has been pressed into making miniature calibration coils by using plastic bobbins to work with 1/8" dia rod magnets. 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 From: George Harris Subject: Re: Lehman pickup coil and magnet. Date: Mon, 01 Mar 1999 12:33:02 +0000 Larry Cochrane wrote: > > Hi Everyone, > > I'm looking for some advice on a replacement for the pickup coil I have > been selling. As some of you know I have been selling a coil and magnet > combination to help people build their sensor without having to worry about > winding a coil. I have a picture of the coil and magnet at > http://psn.quake.net/coilmag.html. > Larry, I have purchased similar coils from Cosmo Corp. in Cleveland. The phone number is 216-861-5594. They have a large catalog of square, round and other shapes with or without terminals. As an example they have about 60 different coils with an ID between .381 and .400. OD varies from .8 to 1.3 and lengths from .19 to 1.7. If you wish to call me (bay area now) I will be glad to look up a number which would fit. Other Ids go from .09 to 3.4 George Harris 707-751-1936 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "James M Hannon" Subject: Re: Lehman pickup coil and magnet. Date: Mon, 1 Mar 1999 15:20:42 -0600 Larry, If you want to keep the cost to a minimum I would stay with 240 volt relay coils. There are a lot of surplus 240 volt relays on the market for around $2. It has been my experience that most relays can be easily dissasembled to extract the coil. Jim Hannon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Erich Kern" Subject: Relay Coils Date: Mon, 1 Mar 1999 13:35:38 -0800 Larry, Hosfelt Electronics in Stuebenville, Ohio has a half dozen relays in their 1999 catalog ( pages 41, 42, 43 ) which match the description of what you're looking for. Some examples: cat. no. 45-613, 240V coil, 9110 ohms, $1.95 each; cat. no. 45-433, 208 volt coil, 36,000 ohms, $3.95 each; cat. no. 45-327, 115 V coil, 11,000 ohms, $2.75 each and 3 others with coil resistances above 10K ohms. Their toll free order number is 800-524-6464 or 888-264-6464. I don't see a website or e-mail address anywhere in their catalog, but they take credit card phone orders and you could ask for a catalog at the same time. They're 3 hours ahead of us, so it might have to wait until tomorrow. Regards, Erich ********************************************************* Please visit our web site at: http://fqs.dconn.com ********************************************************* _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: twleiper@........ Subject: Re: coil.info Date: Mon, 1 Mar 1999 16:47:05 -0500 Sean, There will truly be a gigantic "unrecoverable block" in the database of seismological and miscellaneous knowledge if and when you pass on to that great seismometer down under. I just wonder, will your casket be set on a proper pier? If so, which orientation would you choose, because that is what I'll use for Chelsea's next instrument... Tom _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: pouellette Subject: Re: Lehman pickup coil and magnet. Date: Mon, 01 Mar 1999 21:19:56 -0500 Check in the WW Grainger catalog. Thats where I got mine. If you need it, I'll get you a stock number.. Pete Ouellette Larry Cochrane wrote: > Hi Everyone, > > I'm looking for some advice on a replacement for the pickup coil I have > been selling. As some of you know I have been selling a coil and magnet > combination to help people build their sensor without having to worry about > winding a coil. I have a picture of the coil and magnet at > http://psn.quake.net/coilmag.html. > > The problem is I can no longer find the relay I have been using for the > coil. While the relays I have been using are new, I have been getting them > from a local surplus electronics store. Well I went to the well, so too > speak, one too many times and they no longer have the part. The insignia on > the relay looks like they where made by Grayhill. Grayhill no longer makes > electromechanical relays so I can buy them from a normal distributor. > > The nice thing about the old 220vac relay coil was it had a lot of turns, > over 10k with a dc resistance around 8 to 9k, and fit nicely within the 22 > lb horseshoe magnet. I have looked at some other high voltage high > resistance relays, but they have a much smaller coil. This produces a much > smaller output when placed on my Lehman using the existing 22 lb magnet. > > I was wondering if anyone had any ideas on what I could offer as a coil / > magnet combination. Something I can get off the shelf. I may have too check > into having a coil winding shop make some for me. The problem maybe getting > a suitable bobbin for them to wind the coil on. With the low quantity order > like mine, cost per coil maybe a problem. I was getting the relays for > under $5.00... > > -Larry Cochrane > Redwood City, PSN > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: SW6079@....... Subject: Re: Lehman pickup coil and magnet. Date: Tue, 2 Mar 1999 00:57:44 EST Larry, I am involved in the heating and a/c trade and use 220 vac relays all the time. If you want to give me a phone call some eve. I'm pretty sure I could find a suitable substitute. 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 From: "David A. Nelson" Subject: For Bob Lewis, cant get u direct Date: Tue, 2 Mar 1999 19:37:10 +1300 oops i posted to the events server instead of here sorry everyone else for the clutter Bob, i updated ur email addy on the psn database but when i e-mailed u to say thanks the e-mail addy was rejected as not existing so not sure what the problem is >Hi Dan...I have a new ISP and a new e-mail address: blewis@.............. >Please update this on my station listing, thanks! all done Bob, thanks for the update Dave above is the addy u send me in the text of the letter but i just noticed that the mail u sent came from blewis5@ ........ please clarify for me thanks Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://www.seismicnet.com/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 From: "Francesco" Subject: SDR TIME PROBLEM Date: Tue, 2 Mar 1999 13:10:36 +0100 Hi to all. I have in the last days a serious problem with SDR: =20 sometimes the programm doesn't hook the clock of the pc and therefore = it marks a different time, many minutes or straight times in less. I = don't use the wwv but the European signal DCF77 that enters, through a = a/d board in the serial port of the pc ( 350 pentium) and rule the = clock of the bios. All the functions of the SDR time-clock are disabled. = The same thing happens in the pc that doesn't have DCF77 also.=20 For a good work I must reset the program and so it returns to mark the = right time. Any suggestion? Regards Francesco Nucera I.E.S.N PSN ITALY
Hi to all.
I have in the last days a serious = problem with=20 SDR: 
sometimes the programm  doesn't  hook the clock = of the=20 pc  and therefore it marks a different time,  many minutes or = straight=20 times in less. I don't use the wwv but the European signal DCF77  = that=20 enters, through a  a/d  board in the serial port of the pc ( = 350=20 pentium) and rule the clock of the bios. All the functions of the SDR = time-clock=20 are disabled.  The same thing  happens in the pc that doesn't = have=20 DCF77 also.
For a good work  I must = reset  the=20 program and so it returns to mark the right time.
 
Any suggestion?
 
Regards
Francesco Nucera    I.E.S.N PSN=20 ITALY
 
 
From: "Giacomo" Subject: R: SDR TIME PROBLEM Date: Tue, 2 Mar 1999 13:38:39 +0100 Francesco cos'=E8 SDR? Incomicia a spiegarmi queste cose tecniche che mi farebberono piacere a = saperle. In questi giorni come vedo c'=E8 movimento pure leggero dalle nostre = parti x te cosa significa un normale liberamento di energia di semplice = routine o altro? Ciao G. -----Messaggio originale----- Da: Francesco A: PSN-L Mailing List Data: marted=EC 2 marzo 1999 13.10 Oggetto: SDR TIME PROBLEM =20 =20 Hi to all. I have in the last days a serious problem with SDR: =20 sometimes the programm doesn't hook the clock of the pc and = therefore it marks a different time, many minutes or straight times in = less. I don't use the wwv but the European signal DCF77 that enters, = through a a/d board in the serial port of the pc ( 350 pentium) and = rule the clock of the bios. All the functions of the SDR time-clock are = disabled. The same thing happens in the pc that doesn't have DCF77 = also.=20 For a good work I must reset the program and so it returns to mark = the right time. =20 Any suggestion? =20 Regards Francesco Nucera I.E.S.N PSN ITALY =20 =20
Francesco cos'è = SDR?
Incomicia a = spiegarmi queste=20 cose tecniche che mi farebberono piacere a saperle.
In questi = giorni come vedo=20 c'è movimento pure leggero dalle nostre parti x te cosa significa = un=20 normale liberamento di energia di semplice routine o altro?
Ciao
G.
-----Messaggio = originale-----
Da:=20 Francesco <franuc@......>
A: = PSN-L Mailing=20 List <psn-l@..............>
D= ata:=20 martedì 2 marzo 1999 13.10
Oggetto: SDR TIME=20 PROBLEM

Hi to all.
I have in the last days a = serious problem=20 with SDR: 
sometimes the programm  doesn't  hook = the=20 clock of the pc  and therefore it marks a different time,  = many=20 minutes or straight times in less. I don't use the wwv but the = European=20 signal DCF77  that enters, through a  a/d  board in = the=20 serial port of the pc ( 350 pentium) and rule the clock of the bios. = All the=20 functions of the SDR time-clock are disabled.  The same = thing =20 happens in the pc that doesn't have DCF77 = also.=20
For a good work  I must = reset  the=20 program and so it returns to mark the right time.
 
Any suggestion?
 
Regards
Francesco Nucera    I.E.S.N PSN=20 ITALY
 
 
From: Edgard Gonzales Zenteno Subject: seismograph for local earthquake Date: Tue, 02 Mar 1999 15:01:36 -1200 Hi Everyone, I'm looking for an instrument for the registration of local earthquakes and microseismicity. Edgard Gonzales egz@............ _____________________________________________________________________ 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 From: GeE777@....... Subject: Re: seismograph for local earthquake Date: Tue, 2 Mar 1999 17:34:30 EST In a message dated 3/2/99 12:05:22 PM Pacific Standard Time, egz@............ writes: << I'm looking for an instrument for the registration of local earthquakes and microseismicity. Edgard Gonzales egz@............ __ >> That is what I do. I use a vertical and two horizontal 8 HZ geophones into a MPLI hardware and software.interface. George Erich Seismic Exploration Consultant P. O. Box 2011, Norwalk, CA 90651, U. S. A. Phone (562) 868-6013 e-mail GeE777@....... 33 53.90N 118 04.53W _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Re: Xmas in Dominica: EQs, Volcanoes, and the PSN Date: Tue, 02 Mar 1999 16:38:07 -0700 Wayne- Jody Bourgeois and I gave a one-hour-long, informal talk about our trip to Dominica that was quite like the trip itself: a mixture of geology, interesting and good people, seismology, and beautiful country. We started with a brief introduction about the volcanic activity in the neighboring island of Montserrat, including a "Full color clip, showing the advancement of the flow down the Tar River Valley and out into the sea, set to the music of Arrow a local Montserratian musician who has written songs about the interaction of the islanders and the volcano. 4.7M QuickTime (w/sound)" , to set the stage for what the people of Dominica had heard about constantly for three years prior to the onset of seismic activity southern Dominica in late 1998. Jody summarized the seismo-tectonics of the Caribbean and geology of Dominica. She showed slides of places on the island we visited: our trek to Boiling Lake led by Clem & Madhava, Soufriere and Scots Head during our stay with Andre' & Joyce, sites along the Portsmouth-Roseau commute that you and Dolores took us several times, and of course, the triumphal DARC Boxing Day party at Clement & Hetty's house when the first earthquake was recorded with the Dominica PSN seismograph you assembled from the many PSN-contributed parts. I concluded with a short on-line demonstration of the Dominica PSN website , including some regional and local records and the notice: INCREASE IN EARTHQUAKE ACTIVITY - March 02, 1999. From 05:00 UTC March 02, 1999, Earthquake activity has increased in the south of Dominica. Between 05:00 UTC and 22:00 UTC, the PSN seismograph has recorded in excess of 58 earthquakes, many of which were felt by local residents. This swarm is ongoing and the larger quakes will soon be posted on this site. (which Jody likes because it supports her hypothesis of increased seismic activity in Dominica during the full-moon) -Edward Wayne Abraham J73WA wrote: > Edward > > I have placed your email in the News and Developments section on our > website. I would be greatful if both you and Jody could send me a note > on the outcome so I can add it to the site. > > Wayne -- 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 From: Wayne Abraham J73WA Subject: Re: Xmas in Dominica: EQs, Volcanoes, and the PSN Date: Tue, 02 Mar 1999 22:44:07 -0400 Edward I will place your last email concerning the informal talak in the News and Developments section of our website. As for Jody's observation, she is bang on the money. I have been noticing that seismic activity increases between the last quarter and full moon. According to the local radio, 64 quakes were recorded by the SRU between Midnight and 2:00pm today but I will have to listen tomorrow morning for the update. We counted 58 up till 5:00pm but there were a few extremely small ones which we deliberately left out. It was like carnival for me today. I really feasted on the beautiful seismograms that were recorded on the system. I may have to split up the day's data into 4 6-hour segments and place 4 files on the website. Keep checking out the site http://www.freeyellow.com/members6/dominicapsn/ for updates. Wayne _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Angel Rodriguez Subject: Re: Larry's SOS call for pickup coil Date: Wed, 3 Mar 1999 18:48:25 -0500 At 04:17 AM 03/01/1999 -0500, you wrote: >Larry - I was thinking about making one using a Teflon tape pipe sealant >dispenser with snap-on cover. The core would make a good bobbin, and you >could snap the cover back on when done. What a great idea. I wound a coil on a telfon tape bobbin today and learned the following. I used #34 wire. When I was done it weighed a bit less that a 1/4 pound and had a resitance of 489 ohms. The problem I encountered was that the sides of the bobbin expaned out as I wrapped and the the thickness at the OD is about 1/8 inch wider than at the ID. I will still use it but I will support the sides on the next one. regards, Angel _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Ted Blank Subject: EMON 7.3a beta version available Date: Wed, 3 Mar 1999 20:15:56 -0800 (PST) A new version of EMON is available for any intrepid beta testers willing to give it a try. Here are the new features: *** What's new in EMON Version 7.3 *** EMON 7.3 has several new features to help automate routine tasks. All of the new features are controlled by entries in the OPT file. *** Support for scheduled actions You can now schedule up to two independent actions (usually, to run a BAT file) at predetermined intervals. The intervals can be DAILY, EVEN, ODD, MON, TUE, WED, THU, FRI, SAT, or SUN. In addition you can choose the hour of the day at which each of the two actions is performed. *** Support for event-driven actions You can now specify a command or BAT file to be run each time a quake file is saved to disk. You may specify up to two parameters to be passed to the BAT file. The parameters can be made up of the following items: String Expansion Type Example ------ ---------------- --------------- ---------- %P = path to save files alphanumeric C:\QUAKES\ %N = file name alphanumeric 980804AN.FOX %D = date mm/dd/yy 08/04/98 %T = time hh:mm:ss 05:33 %MO = month numeric 08 %DA = date numeric 04 %YR = year numeric 98 %H = hour numeric 23 %M = minute numeric 59 %X = maximum data value numeric 4096 n = any non-blank char alphanumeric (),/.- etc. Ex: %P%N would expand to C:\QUAKES\980804AN.FOX %N,%X " " " 980804AN.FOX,4096 (if 4096 was max value) %N/%H:%M " " " 980804AN.FOX/13:30 (if quake time = 13:30) *** Support for special "After Multi-file Quake" activity removed In some earlier versions of EMON, users were given the capability to specify one set of actions to perform after each data file was saved, and a different set of actions after a multiple-file quake occured. The support for special multi-file actions has been removed. *** New A/D boards supported Two additional A/D boards are supported. Their OPT file values are: 14 = Axiom Technology AX5210-PG 15 = ANA290 12-bit 8 Chan Prog Gain *** Support for "keyboard locking" Some schools running EMON under Win95 reported that students were inadvertently exiting EMON by pressing F10 to return to Windows, rather than using Ctrl-Esc to bring up the task bar. Also, some students who were not part of the Quake Tracker team at the school played around with the computer enough that significant data files were missed. With EMON 7.3a you can specify three new options in EMON.OPT. LockKeyboardPassword = xxxx 'None = keyboard cannot be locked 'xxxx = 4-character string to lock keybd UnlockKeyboardPassword = yyyy 'None = n/a 'yyyy = 4-character string to unlock kbd InitialKeyboardState = LOCKED 'Locked or Unlocked upon pgm startup By typing either of the four character passwords, the keyboard can be locked or unlocked without stopping EMON. When the keyboard is locked, a message is displayed at the bottom of the screen inviting the user to enter the unlock password. Typing the lock password re-locks the keyboard, including all F1-F10 keys. Passwords are not displayed as they are typed. Let me know if you are interested in trying out the beta version. If enough people want it, I may ask Larry to put it on the web site. Ted Blank San Jose, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Francesco Subject: LARGE QUAKE IN SOUTHERN IRAN Date: Thu, 04 Mar 1999 08:57:51 +0100 At 05.38.26 Ms 6.4 Loc.: 28.31N 51.17E deepth 33.0 SOUTHERN IRAN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Francesco Subject: LARGE AFTERSHOCK IN IRAN Date: Thu, 04 Mar 1999 09:14:31 +0100 07.26.58 MS 5.9~ The same location of main event Francesco Nucera, I.E.S.N. PSN Italy _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Francesco" Subject: IRANIAN SEISMIC CRISIS . ANOTHER LARGE AFTERSHOCK Date: Thu, 4 Mar 1999 11:34:58 +0100 09:51:17 M 5.8 ~ Southern Iran The aftershock continues with many events: 5 > M 5.0 - 3 > m 5.5 From local Tv reporter the notice of many victims and iniureds. Francesco Nucera I.E.S.N. PSN Italy
09:51:17
M 5.8 ~
Southern Iran
 
The aftershock continues with many = events: 5=20 > M 5.0 -  3 > m 5.5
From local Tv reporter the notice of = many=20 victims and iniureds.
 
Francesco Nucera
I.E.S.N. PSN = Italy
From: Larry Cochrane Subject: Re: WinQuake beta releases Date: Thu, 04 Mar 1999 13:42:40 -0800 At 01:49 PM 2/21/99 EST, Bob Laney wrote: >Hi Larry: > >I have gone over WinQuake beta release versions 2.5.7, 2.5.8 and 2.5.9. As >usual, I am impressed with what a great piece of software this is--and it gets >better! In going over the changes, a couple of questions came to mind. > >Double integration--I understand how this is used to get displacement if one >has an accelerometer, but does integrating data from a Lehman or SG sensor >have any physical meaning? If I understand correctly, the output from the SG >and the Lehman varies in proportion to the pendulum's velocity and is >represented by counts. Single integrating some of my event records results in >some interesting looking graphs, but does this give even relative >displacement? Double integration of these records would seem to have no >physical meaning. From what I understand, if you integrate data taken with an accelerometer you get velocity. If you integrate again, you get displacement. So if you integrate the output of a Lehman that is outputting velocity, you should get displacement. I have no idea what one gets if you double integrate velocity. Since the SG sensor's pickup uses displacement, the output below the period of the pendulum is measuring acceleration. On my SG board I have two outputs. One is the direct output, more or less, of the pendulum. There is a 1 pole high pass filter and a 6 pole low pass filter in the signal path. The other output has an integrator in the signal path, as well as some high and low pass filtering, so this output should be velocity below the period of the pendulum. Since teleseismic events have most of their information (at the recording site) below the ~1 second period of the pendulum, this output should be velocity. In fact, if you record both outputs of the SG sensor and integrate, using WinQuake, the "high frequency" or non-integrated output and compare it to the "low frequency" or integrated output, you will see a very similar event file for teleseismic events. I have a more detailed question coming up on the integrating the output of my accelerometer and comparing it to my Lehman. Since the accelerometer has a known output, I should be able to use it to calibrate my other sensor in my house. -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: WinQuake beta releases Date: Thu, 04 Mar 1999 19:23:26 -0700 (MST) On Thu, 4 Mar 1999, Larry Cochrane wrote: > At 01:49 PM 2/21/99 EST, Bob Laney wrote: > >Double integration--I understand how this is used to get displacement if one > >has an accelerometer, but does integrating data from a Lehman or SG sensor > >have any physical meaning? > > I have no idea what one gets if you double integrate > velocity. We can sure find out now that Larry added this feature! Anyone tried it yet??? ****************************************************************************** John Hernlund E-mail: 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 From: Norman Davis WB6SHI Subject: Re: EMON 7.3a beta version available Date: Fri, 05 Mar 1999 08:43:23 -0800 I have looked all over. Where is that program at? At 08:15 PM 3/3/99 -0800, you wrote: >A new version of EMON is available for any intrepid beta testers >willing to give it a try. Here are the new features: > >*** What's new in EMON Version 7.3 *** > >EMON 7.3 has several new features to help automate routine tasks. All of >the new features are controlled by entries in the OPT file. > >*** Support for scheduled actions > >You can now schedule up to two independent actions (usually, to run a BAT >file) at predetermined intervals. The intervals can be DAILY, EVEN, ODD, >MON, TUE, WED, THU, FRI, SAT, or SUN. In addition you can choose the hour >of the day at which each of the two actions is performed. > > >*** Support for event-driven actions > >You can now specify a command or BAT file to be run each time a quake >file is >saved to disk. You may specify up to two parameters to be passed to the >BAT file. The parameters can be made up of the following items: > > > String Expansion Type Example > ------ ---------------- --------------- ---------- > %P = path to save files alphanumeric C:\QUAKES\ > %N = file name alphanumeric 980804AN.FOX > %D = date mm/dd/yy 08/04/98 > %T = time hh:mm:ss 05:33 > %MO = month numeric 08 > %DA = date numeric 04 > %YR = year numeric 98 > %H = hour numeric 23 > %M = minute numeric 59 > %X = maximum data value numeric 4096 > n = any non-blank char alphanumeric (),/.- etc. > > Ex: %P%N would expand to C:\QUAKES\980804AN.FOX > %N,%X " " " 980804AN.FOX,4096 (if 4096 was max value) > %N/%H:%M " " " 980804AN.FOX/13:30 (if quake time = 13:30) > > >*** Support for special "After Multi-file Quake" activity removed > >In some earlier versions of EMON, users were given the capability to >specify one set of actions to perform after each data file was saved, >and a different set of actions after a multiple-file quake occured. The >support for special multi-file actions has been removed. > >*** New A/D boards supported > >Two additional A/D boards are supported. Their OPT file values are: > >14 = Axiom Technology AX5210-PG >15 = ANA290 12-bit 8 Chan Prog Gain > > >*** Support for "keyboard locking" > >Some schools running EMON under Win95 reported that students were >inadvertently exiting EMON by pressing F10 to return to Windows, rather >than using Ctrl-Esc to bring up the task bar. Also, some students who >were not part of the Quake Tracker team at the school played around with >the computer enough that significant data files were missed. > >With EMON 7.3a you can specify three new options in EMON.OPT. > > LockKeyboardPassword = xxxx 'None = keyboard cannot be locked > 'xxxx = 4-character string to lock >keybd > > UnlockKeyboardPassword = yyyy 'None = n/a > 'yyyy = 4-character string to >unlock kbd > > InitialKeyboardState = LOCKED 'Locked or Unlocked upon pgm startup > >By typing either of the four character passwords, the keyboard can be locked >or unlocked without stopping EMON. When the keyboard is locked, a message >is displayed at the bottom of the screen inviting the user to enter the >unlock password. Typing the lock password re-locks the keyboard, including >all F1-F10 keys. Passwords are not displayed as they are typed. > > >Let me know if you are interested in trying out the beta version. If >enough people want it, I may ask Larry to put it on the web site. > >Ted Blank >San Jose, California > > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Bonnie Schafer" Subject: Date: Fri, 5 Mar 1999 13:20:19 -0800 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 From: bc Subject: Re: WinQuake beta releases Date: Fri, 05 Mar 1999 23:03:33 -0500 At 07:23 PM 3/4/99 -0700, you wrote: >On Thu, 4 Mar 1999, Larry Cochrane wrote: >> At 01:49 PM 2/21/99 EST, Bob Laney wrote: >> >Double integration--I understand how this is used to get displacement if one >> >has an accelerometer, but does integrating data from a Lehman or SG sensor >> >have any physical meaning? >> >> I have no idea what one gets if you double integrate >> velocity. > If you double intergrate velocity you get displacement. > We can sure find out now that Larry added this feature! Anyone tried it >yet??? > >****************************************************************************** > > John Hernlund > E-mail: 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 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: WinQuake beta releases Date: Sat, 06 Mar 1999 08:56:07 -0800 bc I disagree.If one double integrates acceleration one gets displacement. Maybe integrating displacement over time (double integrating velocity) is a form of work? regards Barry bc wrote: > At 07:23 PM 3/4/99 -0700, you wrote: > >On Thu, 4 Mar 1999, Larry Cochrane wrote: > >> At 01:49 PM 2/21/99 EST, Bob Laney wrote: > >> >Double integration--I understand how this is used to get displacement > if one > >> >has an accelerometer, but does integrating data from a Lehman or SG sensor > >> >have any physical meaning? > >> > >> I have no idea what one gets if you double integrate > >> velocity. > > > > If you double intergrate velocity you get displacement. > > > We can sure find out now that Larry added this feature! Anyone tried it > >yet??? > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: bc Subject: Re: WinQuake beta releases Date: Sat, 06 Mar 1999 12:16:31 -0500 You are absolutely right, I stand corrected. Thanks for getting me back on track though. Sometimes mouth wags before brain is engaged At 08:56 AM 3/6/99 -0800, you wrote: >bc > I disagree.If one double integrates acceleration one gets displacement. >Maybe >integrating displacement over time (double integrating velocity) is a form >of work? > > regards > Barry > > >bc wrote: > >> At 07:23 PM 3/4/99 -0700, you wrote: >> >On Thu, 4 Mar 1999, Larry Cochrane wrote: >> >> At 01:49 PM 2/21/99 EST, Bob Laney wrote: >> >> >Double integration--I understand how this is used to get displacement >> if one >> >> >has an accelerometer, but does integrating data from a Lehman or SG >sensor >> >> >have any physical meaning? >> >> >> >> I have no idea what one gets if you double integrate >> >> velocity. >> > >> >> If you double intergrate velocity you get displacement. >> >> > We can sure find out now that Larry added this feature! Anyone tried it >> >yet??? >> > > > >_____________________________________________________________________ > >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 From: barry lotz Subject: Earthworm Helicorder Date: Sat, 06 Mar 1999 09:37:51 -0800 I think someone mentioned this before because the name sounds familiar. UNR Univ Nevada Reno has a cool realtime display of a particular sensor in Nevada. Does anyone know if there is access to similar sites for other locations? I got to them thru the USGS menlo park site. Regards Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: George Bush Subject: Re: WinQuake beta releases Date: Sat, 06 Mar 1999 11:12:47 -0800 At 11:03 PM 3/5/99 -0500, you wrote: >At 07:23 PM 3/4/99 -0700, you wrote: ....clip... > >If you double intergrate velocity you get displacement. > >> We can sure find out now that Larry added this feature! Anyone tried it >>yet??? >> Yes! My instrument is located in the garage in the back corner. When I drive in or out of the garage I record a big spike of noise. I used the double intergration feature to look at the displacement of the slab (actually the tilt of the slab). The result was beautiful, all the spikey noise was integrated out and the resultant curve was a flat line that then sloped-down and levelled off as the car arrived and the slab deflected. Now if I could just figure out what the calibration is. George _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Greg Subject: Re: Earthworm Helicorder Date: Sat, 06 Mar 1999 19:21:54 +0000 barry lotz wrote: > in Nevada. Does anyone know if there is access to similar sites for > other locations? I got to them thru the USGS menlo park site. Just how realtime do you mean? I've seen a lot that are updated every 15-30 minutes. Here's a list of some of those: http://aslwww.cr.usgs.gov/Seismic_Data/heli.htm I've also seen a sensor in Southern California somewhere that was showing data through a Java program. Here's some of those: http://benioff.geol.wwu.edu/seismolet.html http://www.ifg.tu-clausthal.de/java/seis/SeisDemApp.html (appears broken) I can't find the one that I tried before. Maybe it's in LA? ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: Earthworm Helicorder Date: Sat, 06 Mar 1999 13:07:14 -0800 Greg It looks like a realtime trace. I'm sure it's delayed a little due to processing. I will check it if I see a teleseismic event coming in on my sensor. Try: > http://www.seismo.unr.edu/ftp/pub/ichinose/JavaWorm/WormWavesApplet.html > Regards Barry Greg wrote: > Just how realtime do you mean? I've seen a lot that are updated every > 15-30 minutes. Here's a list of some of those: > > Greg
      It looks like a realtime trace. I'm sure it's delayed a little due to processing. I will check it if I see a teleseismic event coming in on my sensor. Try: 
http://www.seismo.unr.edu/ftp/pub/ichin
ose/JavaWorm/WormWavesApplet.html


Regards
 Barry
 

Greg wrote:

Just how realtime do you mean? I've seen a lot that are updated every
15-30 minutes. Here's a list of some of those:
 
 
From: Edward Cranswick Subject: Re: Fw: {EarthWaves} "CYBERSYSTEM" FOR EARTHQUAKE ENGINEERING SIMULATION Date: Sat, 06 Mar 1999 15:33:41 -0700 Bonnie- I think the mass distribution of strong motion recorders would be a much more effective means of "reducing and mitigating effects of earthquakes". It is better to record what the Earth is doing in fact, rather than to simulate what you think it might do. -Edward Bonnie Schafer wrote: > Bonnie the crafty crafter > -----Original Message----- > > > >Embargoed until 2:00 P.M., ESTMedia contact: February 23, 1999 > >Joel Blumenthal NSF PR 99-13 > >(703) 306-1070/jblument@.............. contact:Priscilla Nelson > >(703) 306-1361/pnelson@....... > > > > NSF TO ESTABLISH "CYBERSYSTEM" > > FOR EARTHQUAKE ENGINEERING SIMULATION > > > > A top National Science Foundation [NSF] official today described > >to a House > >subcommittee how the NSF plans to use information technology [IT] to > >establish a > >cyber Network for Earthquake Engineering Simulation [NEES]. > > Testifying before the House Committee on Science' Subcommittee on > >Basic > >Research, Joseph Bordogna, NSF acting deputy director, said that NEES > >"will > >change the face of earthquake engineering." His statement was part of > >testimony in favor of re-authorizing the National Earthquake Hazards > >Reduction > >Program [NEHRP]. > > NEES "will use IT to serve a critical national need (reducing and > >mitigating effects of earthquakes): to help save lives and money; and > >to make more > >efficient use of government's investment in science and engineering," > >Bordogna said. > >NSF is seeking $7.7 million in its fiscal 2000 budget request for the > >first year of aplanned five-year, $81.9 million program for NEES. > >Bordogna told the subcommittee, chaired by Rep. Nick Smith (R-Mich.), > >that NEES, like NEHRP, was initiated in response to a mandate from > >Congress to take > >stock of the nation's experimental and testing capability in > >earthquake > >engineering. > > NEES will use a computer network to bring "a complete collection > >of > >state-of-the-art facilities under one `virtual roof,'" Eugene Wong, > >NSF's assistant director > >for engineering, said. "It will provide remote access to users, and > >make a > >complete system of testing and experimental facilities available to > >the entire > >earthquake engineering community." Networking software will enable the > >system > >to use models and databases to develop model-based simulation, Wong > >added. > >More than 30 U.S. institutions currently have some kind of > >experimental > >earthquake engineering facilities. These include shake tables for > >earthquake > >simulations, reaction walls for pseudodynamic testing, geotechnical > >centrifuges > >for testing soils during earthquakes, and floor reaction systems. > >NEES funds would be used to: create new shake tables and upgrade > >existing > >shaketables; build centrifuges and Tsunami testing tanks; build new > >reaction walls, > >load simulators and response modifiers; and create field test > >facilities (i.e. mobile > >equipment, field sites and post-quake labs). Funds will also provide > >for system > >integration and to ensure completion of all corefacilities. Bordogna > >stated that NEES > >can serve as an educational tool for students and the public, and as > >the primary > >repository of earthquake engineering physical experiments and data. He > >added that > >NEES also will leverage public and private investments in the $100 > >billion-a-year IT > >industry by using existing software and making effective use of the > >high-speed > >networking infrastructure that is one of NSF's most successful > >ventures. > > -NSF- > > > > > >^^ To UNSUBSCRIBE: Send "unsubscribe earthwaves" to majordomo@........... > >^^ To SUBSCRIBE: Send "subscribe earthwaves" to majordomo@........... > >^^ To SUBSCRIBE ANOTHER: Type "subscribe earthwaves name@........." > >^^ All commands should be placed in body of message, with no quotes > >^^ Auto-approval occurs when confirmation email is returned by subscriber > >^^ Check current EQ reports: http://www.earthwaves.com/current.html > > > > _____________________________________________________________________ > > 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 From: Edward Cranswick Subject: Re: Water Valley, MS quake Date: Sat, 06 Mar 1999 15:42:47 -0700 Charlie- I showed your record to Mark Meremonte yesterday when we were looking at the data recorded by USGS instruments in Memphis. Unfortunately, our instruments did not start recording until the day after the Water Valley event. -Edward Charlie Rond wrote: > 2/25/99 Event > > ------------------------------------------------------------------------ > Name: 990225CA.RM1 > 990225CA.RM1 Type: unspecified type (application/octet-stream) > Encoding: base64 > > ------------------------------------------------------------------------ > > Charlie Rond -\/\--Public Seismic Network-Memphis > http://gandlf.ceri.memphis.edu/~rond/psn > -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Greg Subject: Re: Earthworm Helicorder Date: Sun, 07 Mar 1999 01:14:03 +0000 barry lotz wrote: > It looks like a realtime trace. I'm sure it's delayed a little > due to processing. I will check it if I see a teleseismic event coming > in on my sensor. Try: > > > http://www.seismo.unr.edu/ftp/pub/ichinose/JavaWorm/WormWavesApplet.html It's a simulation of an event for now. The date in the windows is 1998, unless that's incorrect. It's says that they hope to make it real-time in the future. It's neat though. ,Greg _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Re: WinQuake beta releases Date: Sat, 06 Mar 1999 18:24:45 -0700 Barry- Well, integrating or any other kind of analytic math has always been alot of work for me to understand, so forgetting about the niceties of calculus for a second, I will give the cartoon version of the ground motion story. This presentation will be in terms of average values of ground motions, and not instantaneous values, i.e., dx and dt. Thus it will be wrong in terms of accurate scaling, i.e., the constant multiplier that determines the scalar values (the '=' represents proportionality rather than equality), but the units will indicate what is happening during integration. Velocity, V, is displacement, X, divided by time, T: V = X / T e.g., cm / s Acceleration, A, is velocity divided by time: A = V / T = (X / T) / T e.g., cm / s / s = cm / s**2 In effect, when we integrate over time, we multiply by time. So if we integrate acceleration once, we obtain velocity: A * T = ( V / T ) * T = V e.g., cm / s If we integrate velocity, we obtain displacement: V * T = ( X / T ) * T = X e.g., cm If we integrate displacement, X * T = M e.g., cm * s or cm-s where M scales with seismic moment (which is derived from the classical definition of angular moment in terms of force applied along a moment arm of given length, and which is akin to, but not the same as, seismic energy, i.e., work), when X is ground displacement. In a perfect world, which is what geophysicists like to assume about the Earth (geologists believe the Earth simply is), simple slip on a fault produces a single-sided displacement pulse in the far-field (at a distance away from the fault that is an order-of-magnitude greater than the length of fault that slipped): as the seismic wave propagates past the observer, the ground goes up and then goes down (or reverse), returning essentially to its pre-event position. The logarithm of the peak amplitude of that pulse is proportional to the Richter local magnitude (ML). The duration (i.e., half-period) of that single-sided pulse is proportional to the length of the fault that slipped. The area under that pulse, i.e., the integral of the displacement, is proportional to the seismic moment of the earthquake. So, Singly-integrated A = V Singly-integrated V = X Singly-integrated X = M Doubly-integrated A = X Doubly-integrated V = M Doubly-integrated X = ? In the interest of not confusing anybody, particularly myself, I will not continue any further. -Edward barry lotz wrote: > bc > I disagree.If one double integrates acceleration one gets displacement. Maybe > integrating displacement over time (double integrating velocity) is a form of work? > > regards > Barry > > bc wrote: > > > At 07:23 PM 3/4/99 -0700, you wrote: > > >On Thu, 4 Mar 1999, Larry Cochrane wrote: > > >> At 01:49 PM 2/21/99 EST, Bob Laney wrote: > > >> >Double integration--I understand how this is used to get displacement > > if one > > >> >has an accelerometer, but does integrating data from a Lehman or SG sensor > > >> >have any physical meaning? > > >> > > >> I have no idea what one gets if you double integrate > > >> velocity. > > > > > > > If you double intergrate velocity you get displacement. > > > > > We can sure find out now that Larry added this feature! Anyone tried it > > >yet??? > > > > > _____________________________________________________________________ > > 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 From: S-T Morrissey Subject: hinge effects Date: Sat, 6 Mar 1999 20:40:46 -0600 (CST) Brett, Thanks for your recent note about modeling the mechanical period of the vertical leaf-spring configuration and the formula for calculating the restoring force effect of the flat leaf orthogonal hinges. It has brought out an important point about the flat-leaf hinge assembly on the STM that is missing from the drawing, namely the "free air" length of the hinges. (I did post a note about it last Nov 24) When I prepare the aluminum angle brackets that the hinges are epoxied to, I file off the outside corners of the angles in the area where the hinges go from one bracket to the other. I file the corner at a 45deg angle, removing about 1/16 or more from each orthogonal side, so when the hinges are assembled, the free air distance is at least 0.125 inches. The actual pivot point is within the hinge thickness (0.005") of the corner of the angles. This free air length results in about 1/3 the force you estimated for 0.040", but it is still significant. This method of providing the hinge clearance has been common practice in many of the hinge designs I have seen in large mechanical seismometers over the years. But now you have provided the reason that it is important, especially when thicker spring material is used to provide a strong assembly. And clearly, if, for example, 0.003" material is used, the force would be about 1/5 of that of the 0.005", but would probably still be strong enough. I used the 0.005" bronze strap because I have about 50 lbs of it. But this relatively significant force does complicate the task of modeling the behavior of the vertical seismometer as the leaf spring is adjusted for minimal restoring force and long periods. In the case of the horizontal, it means that when the boom is exactly horizontal with respect to gravity, the mechanical period resulting from the hinge force will prevail, and as the boom is further raised at the mass end, a small component of g will be cancelling the hinge force, up to the point of instability and infinite period. From this we can see why period instability (and thermal effects) gets to be a serious problem when the actual hinge geometry (center of flexure) changes very slightly with the angle of the boom when the hinges themselves are exerting a significant restoring force. For the vertical configuration, the force of the spring has to offset the force of the hinge stiffness to realize longer periods. This was largely ignored in seismometer designs, which assumed that the hinges exerted zero force compared to the support spring. In the old literature on long period vertical sensors, this was interpreted as configuring the "zero-length" spring for a numerically positive effective length, slightly longer than the number considered as "zero length". I am adding updates to the drawing of the seis, and I will add an inset showing this detail of the hinge assembly. 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 From: "Bonnie Schafer" Subject: Re: Fw: {EarthWaves} "CYBERSYSTEM" FOR EARTHQUAKE ENGINEERING SIMULATION Date: Sat, 6 Mar 1999 20:51:21 -0800 Hi Edward, Actually, I never thought of that but now that you have brought it to my attention it makes perfect sense. Thanks 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 From: Wayne Abraham J73WA Subject: Re: WinQuake beta releases Date: Sun, 07 Mar 1999 08:29:11 -0400 Edward Don't you worry - my confusion won't last forever. Wayne _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Wayne Abraham J73WA Subject: Web-page error Date: Sun, 07 Mar 1999 08:34:36 -0400 Hello all For those of you who regularly visit the new Dominica Public Seismic Network website regularly, you may have noticed that something has gone wrong with the data in there. This is because yesterday, Saturday, the people who host the site upgraded their system. They have replaced all my recent files with older (probably backup) copies. So far I have been unable to update them. Hopefully they will get their act together soon so that I can update them again. http://www.freeyellow.com/members6/dominicapsn/ Wayne. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: robert barns <75612.2635@..............> Subject: Re: WinQuake beta releases Date: Sun, 7 Mar 1999 14:06:08 -0500 About 2 years ago, I posted plans for a calibrator for a horizontal seismometer. You can see this at psn.quake.net/calibrate.html Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Charlie Rond Subject: Re: EMON 7.3a beta version available Date: Sun, 07 Mar 1999 14:39:47 -0600 Ted, >A new version of EMON is available for any intrepid beta testers >willing to give it a try. Here are the new features: I'm anxious to give it a try here! Let us know the next step. Keep up the good work.. Charlie Rond -\/\--Public Seismic Network-Memphis http://gandlf.ceri.memphis.edu/~rond/psn _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Re: WinQuake beta releases Date: Sun, 07 Mar 1999 14:52:25 -0700 Wayne- Where do I get copies of the recents, such as, "18:16 UTC March 02, 1999 [largest quake of the day and aftershock. Was felt over a wide area]"? -Edward Wayne Abraham J73WA wrote: > Edward > > Don't you worry - my confusion won't last forever. > > Wayne > > _____________________________________________________________________ > > 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 From: Malcolm Purves Subject: Re: WinQuake beta releases Date: Sun, 07 Mar 1999 23:09:15 +0000 Excellent exposition Ed. I liked that, I think I am not too confused:-) Back in my youth I was familiar with dx/dy etc for the progression from displacement to velocity to accel. But I had previously, fuzzily, thought that the integral of the displacement might be related to the energy and the Richter Mag., of the quake. But I never got round to thinking about it in detail. Thanks, Malcolm. Edward Cranswick wrote: > > Barry- > Well, integrating or any other kind of analytic math has always been alot of work > for me to understand, so forgetting about the niceties of calculus for a second, I will > give the cartoon version of the ground motion story. This presentation will be in terms etc,snip. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Francesco" Subject: I.E.S.N EQ MESSAGE NOTIFICATION Date: Tue, 9 Mar 1999 16:50:40 +0100 DATE H LAT LONG LOCALIZ = M -------------------------------------------------------------------------= ------------------ 990308 12:25:45 52.13N 159.32E EST OF KAMTCHATKA 6.8 MS This is a preliminary information based on the recorder of all I.ES.N. = italian stations, subject to verification and correction
DATE       =20 H            =        =20 LAT        =20 LONG       =20 LOCALIZ        M
----------------------------------------------------------------= ---------------------------
 
990308  = 12:25:45   =20 52.13N  159.32E     EST OF=20 KAMTCHATKA     6.8 MS
 
 
This is a preliminary information = based on the=20 recorder of all I.ES.N. italian stations, subject to verification and=20 correction
From: "Mark Robinson" Subject: Something fairly large just happened Date: Tue, 9 Mar 1999 04:52:34 +1300 look to the machines lads and ladettes Mark G Robinson | ZL2TOD | other@............... Box 8770, Auckland 1035, New Zealand Phone +64-9-846-3296 | Fax +64-9-849-7408 ------------------------------------------------ 09 Mar 1562 Kissing in public becomes punishable by death in Naples. 09 Mar 1929 A magnitude 6.9 earthquake centred at Arthurs Pass is felt = from Auckland to Bluff. 09 Mar 1956 Opo the dolphin found dead at Opononi. 09 Mar 1997 Lulu Ellen Caitcheon born.
look to the = machines lads and=20 ladettes
 
 
Mark G Robinson = | ZL2TOD | other@...............
Box=20 8770,       Auckland=20 1035,       New Zealand
Phone=20 +64-9-846-3296    |     Fax=20 +64-9-849-7408
------------------------------------------------
09 = Mar=20 1562 Kissing in public becomes punishable by death in Naples.
09 Mar = 1929 A=20 magnitude 6.9 earthquake centred at Arthurs Pass is felt=20 from
           = ;=20 Auckland to Bluff.
09 Mar 1956 Opo the dolphin found dead at = Opononi.
09=20 Mar 1997 Lulu Ellen Caitcheon born.
From: repnizza Subject: Re: QUAKE IN PROGRESS Date: Mon, 08 Mar 1999 14:19:45 +0100 in Piedmont Region (Italy) P & S saturation: Time of arrival: 12.38 UTC Localization: Kamchatka or nearbies ??? Roberto Pozzo Liberio Rossi ha scritto: > >From LAT 43.922 LONG. 10.532E quake in progress. > org. 12.34.6 UTC. > Saluti Liberio rossi LUCCA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Ted Blank Subject: Re: EMON 7.3a beta version available Date: Mon, 8 Mar 1999 09:32:27 -0800 (PST) Norman, I have sent you and four others e-mail with the new code attached. Thanks, look forward to your comments. Ted Blank San Jose, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Liberio Rossi" Subject: QUAKE IN PROGRESS Date: Mon, 8 Mar 1999 14:03:32 +0100 From LAT 43.922 LONG. 10.532E quake in progress. org. 12.34.6 UTC. Saluti Liberio rossi LUCCA _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Wayne Abraham J73WA Subject: DPSN Website back in order Date: Mon, 08 Mar 1999 19:55:18 -0400 Hello all Just to inform you all that the Dominica Public Seismic Network website http://www.freeyellow.com/members6/dominicapsn/ is in order again. I have reloaded all my files and updated the site with the larger quakes from the swarm of March 02, 1999. Wayne _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Norman Davis WB6SHI Subject: Re: EMON 7.3a beta version available Date: Mon, 08 Mar 1999 20:04:27 -0800 Thanks. Am still trying to find a cheap a/d card. At 09:32 AM 3/8/99 -0800, you wrote: >Norman, I have sent you and four others e-mail with the new code >attached. Thanks, look forward to your comments. > > >Ted Blank >San Jose, California > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > > Norman M. Davis WB6SHI Shingle springs, CA Email: normd@............. http://www.directcon.net/normd/index.htm ICQ: 7192318 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Ted Blank Subject: Re: EMON 7.3a beta version available Date: Mon, 8 Mar 1999 20:48:54 -0800 (PST) Cheapest one I know of (good quality) is ComputerBoards Inc. 12-bit 8 channel for $149. It is on their web page, www.computerboards.com as I recall. Anyone know where to get this one cheaper? Model is CIO-DAS/08. Ted Blank San Jose, California On Mon, 8 Mar 1999, Norman Davis WB6SHI wrote: > Thanks. Am still trying to find a cheap a/d card. > > At 09:32 AM 3/8/99 -0800, you wrote: > >Norman, I have sent you and four others e-mail with the new code > >attached. Thanks, look forward to your comments. > > > > > >Ted Blank > >San Jose, California > > > > > >_____________________________________________________________________ > > > >Public Seismic Network Mailing List (PSN-L) > > > >To leave this list email listserver@.............. with the body of the > >message: leave PSN-L > > > > > Norman M. Davis WB6SHI Shingle springs, CA > Email: normd@............. > http://www.directcon.net/normd/index.htm > ICQ: 7192318 > > > _____________________________________________________________________ > > 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 From: Larry Cochrane Subject: Re: EMON 7.3a beta version available Date: Mon, 08 Mar 1999 21:08:32 -0800 All, Sorry for the blatant plug but my 12 bit A/D card is only $30.00 more and the small profit I make helps pay for the cost to run this list....You also get a registered copy of my WinQuake program, a $30.00 value as they say. The current version of Emon will work with my board (thanks Ted!) or you can use my SDR program. With the $15.00 WWV option, and a dedicated short-wave receiver, you can have accurate event file timing if you use SDR. Regards, Larry Cochrane Redwood City, PSN At 08:48 PM 3/8/99 -0800, you wrote: > >Cheapest one I know of (good quality) is ComputerBoards Inc. 12-bit 8 >channel for $149. It is on their web page, www.computerboards.com as I >recall. Anyone know where to get this one cheaper? Model is CIO-DAS/08. > > >Ted Blank >San Jose, California > >On Mon, 8 Mar 1999, Norman Davis WB6SHI wrote: > >> Thanks. Am still trying to find a cheap a/d card. >> >> At 09:32 AM 3/8/99 -0800, you wrote: >> >Norman, I have sent you and four others e-mail with the new code >> >attached. Thanks, look forward to your comments. >> > >> > >> >Ted Blank >> >San Jose, California > >> Norman M. Davis WB6SHI Shingle springs, CA >> Email: normd@............. >> http://www.directcon.net/normd/index.htm >> ICQ: 7192318 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Calibrating my Lehman using integration... Date: Tue, 09 Mar 1999 01:41:31 -0800 Hi Everyone, I have some questions for the experts on how to calibrate my Lehman using the FBA-23 accelerometer I am monitoring. First some background; On 2/04/99 at 0:19:36 UTC we had an interesting local double event. The first event was ~ML 3.8 and the second event was somewhat smaller. The events where about 72km from my house. I recorded both events on scale with my Lehman, peek count = 32100 out of 32768, and the FBA-23 recorded a peek count of 43. The files I am using for the information below can be downloaded from my system. The event files are 990204a.lc1, my N-S Lehman, and 990204a.lc5 the N-S channel of the FBA-23. The two sensors are located right next to each other in a spare bedroom. Since I know the characteristics (sensitivity) of FBA sensor, in fact it just got calibration at Kinemetrics a few days before the event!, I should be able to use it to calibrate my Lehman. The problem is the FBA outputs acceleration and my Lehman outputs velocity. Using WinQuake's integration feature, I should be able to convert the FBA data to velocity, by integrating once, and use this to come up with the sensitivity of my Lehman. The FBA channel has the following sensitivity; Full scale is +- 2g, this gives a min/max A/D count of 32768 (16 bit A/D system) so each A/D count is 61.03 ug ( 65536 counts / 4 g). The event produced a peek count of 43, so the peek acceleration was around 2.62 mg (61.03 ug * 43). After integrating the FBA event file, I get a peek count of 1.39 (Note: you will need to use the newest WinQuake beta release to see numbers below 1 after integration). After doing the integration, the event file looks very similar to my Lehman around the S wave, except for the 32100 to 1.39 count difference. Since there is a 32100 to 1.39 difference, I think I can say that my Lehman is ~23,093 times more sensitive then the FBA sensor, after converting to velocity. That would make sense, since the FBA is a strong motion sensor and my Lehman is a higher gain device. So my question basically gets down to what is the 1.39 number I get after doing the integration and can I say that my Lehman has a gain of 23K that number, more or less? Since the FBA senors is a little out of the background noise of the my system (about +- 5 counts or +- .3 mg) there is some error in the 2.62 mg and 1.39 numbers. Part of the 23k gain difference is the amplification between the pickup coil on the Lehman and the A/D converter. I think the gain of my amp / filter card is set too ~5K. If the gain is 5K, then the coil / magnet combination is only around 4.6 times more sensitive then the FBA, after integrating etc.... What I would like to do is measure the actual sensitivity of the coil and magnet, some how, and compare it to the calculated number using the FBA / WinQuake integration method. I think it would be interesting too try and "close the loop" and calibrate my Lehman using the two methods and see how close I can get. One more thing, it has to do with the damping of my Lehman. I think it is safe to say that the actual amount of damping of my Lehman has little effect on my results. My Lehman currently has a natural period of around 8 seconds (If I set it any longer I constantly have to adjust the #$%&^ thing). As I understand it, damping effects the response around the natural period of the pendulum, more of less.... Since the period of the wave used for the peek measurements information above are around 3 to 5 hz, well above the 8 sec period of my Lehman, a little under or over damped system should not effect things too much. Is this a correct statement? Thanks for any input... Regards, Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: Calibrating my Lehman using integration... Date: Tue, 09 Mar 1999 08:19:13 -0700 (MST) On Tue, 9 Mar 1999, Larry Cochrane wrote: > Since I know the characteristics (sensitivity) of FBA sensor, in fact it > just got calibration at Kinemetrics a few days before the event!, I should > be able to use it to calibrate my Lehman. The problem is the FBA outputs > acceleration and my Lehman outputs velocity. Using WinQuake's integration > feature, I should be able to convert the FBA data to velocity, by > integrating once, and use this to come up with the sensitivity of my Lehman. Larry, The only problem is that each device will have a different frequency response. This means that the FBA sensor may show its maximum amplitude for a certain frequency component of the signal, and that frequency will have a different amplification for the Lehman, and will probably not be the maximum amplitude frequency for the Lehman record. I suppose the best way to determine the differences in amplitude response is to integrate your FBA sensor's record, then do an FFT. Compare this FFT with the FFT for the Lehman sensor; these should be different in a way that reflects each instrument's response. If the FFTs are very similar, then you can certainly make a correlation between the FBA and the Lehman that will not be too far from its real value. But because Lehmans are lower frequency instruments I don't know that this will be the case. Perhaps the best thing to do is make a narrow bandpass filter for each record over the same narrow frequency range (some where between the natural frequency for the FBA and the Lehman where the signal is strong). Then do an IFFT in order to find the maximum counts and use these for your calibration. Another complicated method would involve subtracting one FFT from the other, which I won't say much about since it is probably unnecessary and also beyond the capabilities of Winquake (but this would be a cool feature!)... ****************************************************************************** John Hernlund E-mail: 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 From: robert barns <75612.2635@..............> Subject: my web site Date: Tue, 9 Mar 1999 11:19:04 -0500 Hi gang, what's shakin'? I got my website working yesterday. It has some pics of seismometers a= nd a lot of other stuff. www.webspan.net/~bbarns Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Karl Cunningham Subject: Re: Calibrating my Lehman using integration... Date: Tue, 09 Mar 1999 08:40:06 -0800 Hi Larry -- Adding a couple of cents to what John said... As John said, it is important that the records you are comparing have similar bandwidths. If you can be certain that there is a frequency range of flat response from both (understanding that one is velocity and the other is acceleration), you can use WinQuake to do the same bandpass filtering to both, then integrate the acceleration to velocity and compare the waveforms. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: Calibrating my Lehman using integration... Date: Tue, 09 Mar 1999 11:44:02 -0700 (MST) On Tue, 9 Mar 1999, Karl Cunningham wrote: > Hi Larry -- > Adding a couple of cents to what John said... > As John said, it is important that the records you are comparing have > similar bandwidths. If you can be certain that there is a frequency range > of flat response from both (understanding that one is velocity and the > other is acceleration), you can use WinQuake to do the same bandpass > filtering to both, then integrate the acceleration to velocity and compare > the waveforms. Karl, Wouldn't you want to integrate the acceleration record first, and then apply the bandpass to it? That way you are working in a velocity spectrum for both records... ****************************************************************************** John Hernlund E-mail: 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 From: Ted Blank Subject: Re: EMON 7.3a beta version available Date: Tue, 9 Mar 1999 12:31:22 -0800 (PST) Yes, by all means keep your money circulating within the PSN! Hmmm, maybe I'll contact some of these A/D board companies and ask them if they will make a donation to the PSN for every board a member buys. Couldn't hurt to ask...kind of like Points for COmputers at our local mall. Ted Blank San Jose, California On Mon, 8 Mar 1999, Larry Cochrane wrote: > All, > > Sorry for the blatant plug but my 12 bit A/D card is only $30.00 more and > the small profit I make helps pay for the cost to run this list....You also > get a registered copy of my WinQuake program, a $30.00 value as they say. > > The current version of Emon will work with my board (thanks Ted!) or you > can use my SDR program. With the $15.00 WWV option, and a dedicated > short-wave receiver, you can have accurate event file timing if you use SDR. > > Regards, > > Larry Cochrane > Redwood City, PSN > > > At 08:48 PM 3/8/99 -0800, you wrote: > > > >Cheapest one I know of (good quality) is ComputerBoards Inc. 12-bit 8 > >channel for $149. It is on their web page, www.computerboards.com as I > >recall. Anyone know where to get this one cheaper? Model is CIO-DAS/08. > > > > > >Ted Blank > >San Jose, California > > > >On Mon, 8 Mar 1999, Norman Davis WB6SHI wrote: > > > >> Thanks. Am still trying to find a cheap a/d card. > >> > >> At 09:32 AM 3/8/99 -0800, you wrote: > >> >Norman, I have sent you and four others e-mail with the new code > >> >attached. Thanks, look forward to your comments. > >> > > >> > > >> >Ted Blank > >> >San Jose, California > > > >> Norman M. Davis WB6SHI Shingle springs, CA > >> Email: normd@............. > >> http://www.directcon.net/normd/index.htm > >> ICQ: 7192318 > > > _____________________________________________________________________ > > 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 From: Karl Cunningham Subject: Re: Calibrating my Lehman using integration... Date: Tue, 09 Mar 1999 13:14:53 -0800 John -- Absolutely right! Otherwise the integrator would not have the full spectrum to work with. Thanks for pointing that out. Another thing I forgot to mention is that it is important that both sensors have a significant amount of flat bandwidth that overlaps, or they'll never agree. -- Karl At 11:44 AM 3/9/99 -0700, you wrote: >Karl, > Wouldn't you want to integrate the acceleration record first, and then >apply the bandpass to it? That way you are working in a velocity spectrum for >both records... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: Hinges and things Date: Tue, 09 Mar 1999 20:10:35 -0500 Seismo builders, Recently, I was looking at calculating the restoring force on a crossed-spring hinge. That got me wondering what it would take to modify the design to have even lower resistance. I think I've stumbled on a configuration that appears to have zero restoring force. I wonder if it will work in practice? see: zerohnge.pdf Also, the file I recently put up regarding the geometry of a leaf spring vertical has now been put into ".pdf" form. Was previously having trouble getting the drawings to look right when I made the .pdf. vertgeom.pdf available for downloading at: http://members.home.net/nordgren/public/ Brett Nordgren _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: GeE777@....... Subject: Rotating Horizontal Seismic Data Date: Tue, 9 Mar 1999 20:40:57 EST Hello All, I am now able to record earthquake data from a three component 10 HZ geophone. The geophone elements are one vertical and the two horizontal, east-west and north-south. I would like to process the horizontal recorded seismic events and determine the direction and relative amplitude of the shear wave. Does anyone know of an application, preferably a windows program that can do this? The data can be in two spreadsheet columns or the like. I only expect to record near by events with this system. I am using Vernier Software's MultiPurpose Lab Interface hardware and software to input the three channels into my computer. Anyone who wants to know more about this recording method e-mail dvernier@........... George Erich Seismic Exploration Consultant P. O. Box 2011, Norwalk, CA 90651, U. S. A. Phone (562) 868-6013 e-mail GeE777@....... 33 53.90N 118 04.53W _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Angel Rodriguez Subject: Re: Rotating Horizontal Seismic Data Date: Tue, 9 Mar 1999 21:16:02 -0500 Hi, I have been trying a program call Seisan the may be able to do that. I will be using it to locate local evenst from my 3 componemt 8hz device that I hope to have next wedk. I know that I will be able to get the azimuth of the event. It runs in dos, w95 and on my w98. You can get the manual in PDF format at my ftp ftp://ftp.barriles.com/sismos be forwarned that my ftp is slow becasue it=B4s at the end of a verly long string of routers in Panama. I also have a program that will convert from PSN format to seisan format Seisan does a bunch of stuff Warmly angel _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Displacement calibration Date: Tue, 09 Mar 1999 20:24:21 -0800 While we are on calibration, I thought I'd mention a new find for me, though it may not be new to others. I was trying to calibrate a homemade LVDT for the high gains STM uses in the VBB sensor. I have only a micrometer with a resolution of 0.001". However I have a weigh scale that reads to 0.1gms. So what I did was calibrate the LVDT for a lower gain with the micrometer so ~3vts=0.020". Then I constructed a 12" long cantilivered beam of 0.125" X 1.00" section. I connected the LVDT at the end of the beam (axis vertical). Normally the deflection of a cant. beam w/concentrated end load would be PL^3/(3EI). Because I couldn't trust my section and length measurements, decided to determine L^3/(3EI). Regardless of gain this should be constant. I used the low gain setting with weights from 0.6 to 20gms. and obtained a factor("/gm). then I increased the LVDT gain ~20 times and applied the lower valued weights (0.2-2.0gms) and got a gain of ~3000vts/in with minimal difficulty. I think with a slightly thicker cantiliver or shorter length I could increase the gain higher yet, since the deflection would be lower. As a note ,I took a zero reading then loaded the beam then took a new zero reading to determine the deflection. There was long term drifting probably due to thermal gradients on the steel cantilever. Regards Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Charles R. Patton" Subject: Re: Hinges and things Date: Tue, 09 Mar 1999 22:07:56 -0800 Brett Nordgren wrote: > I think I've stumbled on a > configuration that appears to have zero restoring force. I wonder if i= t > will work in practice? > > see: zerohnge.pdf Brett, The first Rolamite patents started about 1972 by Dean E. Gladow and were assigned to Rolamite Inc. in San Francisco, CA. Representative patent num= bers are 3710631, 3691871. As I recall Dean worked for a govt. lab, so the Rol= amite corp licensed the patents to commercially develop them. One later patent= by someone else is 4438983. I have played with these bearings and they have incredibly low friction and hysteresis, even in large sizes. One variati= on I came up with solves one big problem which is that in the previous forms t= he bearings require the use of pressure to keep the cylinders together =96 t= he minute they go into tension, they separate and the performance (geometry)= of the pivot is uncertain. The method to do this is quite simple. Imagine = a stepped cylinder where the top and bottom are a given diameter and the ce= nter section is about 1/2 (not critical) that diameter. Take two of these cylinders and wrap the bands as you would previously. Now the tension in= the center band has two right angle vector components, one acting to keep the bearing together, and the other to keep the bands in tension. This beari= ng is very well behaved. This bearing can be easily constructed with drill ro= d and drill bushings and SS or brass shim stock. to have excellent performance. Charles R. Patton _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: Rotating Horizontal Seismic Data Date: Wed, 10 Mar 1999 11:05:16 -0700 (MST) On Tue, 9 Mar 1999 GeE777@....... wrote: > I am now able to record earthquake data from a three component 10 HZ geophone. > The geophone elements are one vertical and the two horizontal, east-west and > north-south. I would like to process the horizontal recorded seismic events > and determine the direction and relative amplitude of the shear wave. Does > anyone know of an application, preferably a windows program that can do this? > The data can be in two spreadsheet columns or the like. I only expect to > record near by events with this system. > I am using Vernier Software's MultiPurpose Lab Interface hardware and > software to input the three channels into my computer. Anyone who wants to > know more about this recording method e-mail dvernier@........... > George Erich George, I have written many fortran codes for doing this type of thing. You will need to save the data in ASCII format. The way to do this is very simple, you just use rotation matrices for the vector components of motion. Doing this, you can rotate your data into an reference frame. It is best to look at the data in several ways: - Rotate it to the back azimuth to source direction and the vary the sideways tile angle. - Rotate the horizontal components all around 360 degrees. People do this to try and find anisotropy... As far as getting this into windows... You could load the data into excel or something like that and accomplish the same thing if you have a very fast computer... I would try this first before getting too fancy. ****************************************************************************** John Hernlund E-mail: 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 From: Brett Nordgren Subject: More geometry Date: Thu, 11 Mar 1999 09:37:05 -0500 To all: The file "vertgeom.pdf" has been updated today to include some new graphs. These show the results from adjusting the dimensions of a leaf spring vertical to achieve zero net restoring force. Located at: http://members.home.net/nordgren/public/ Brett Nordgren bnordgren@.............. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Dick Webb Subject: Reading Seismograms Date: Fri, 12 Mar 1999 08:14:20 -0500 For the past few years, I've been using "Earthquake Interpretations A manual for Reading Seismograms" by Simon as an aid in reading seismograms. I've not been able to locate other guides. Do you know of any books or references that give good guidance on making the proper picks. Particularly teleseisms. Dick _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: Reading Seismograms Date: Fri, 12 Mar 1999 10:42:10 -0700 (MST) On Fri, 12 Mar 1999, Dick Webb wrote: > For the past few years, I've been using "Earthquake Interpretations A > manual for Reading Seismograms" by Simon as an aid in reading seismograms. > I've not been able to locate other guides. Do you know of any books or > references that give good guidance on making the proper picks. > Particularly teleseisms. Dick, I think most people do things similar to Larry's arrival time picks by plugging in an epicentral distance, depth, and a reference earth model. The reference earth model is itself an inversion of arrival times averaged for many events. If you wanted to get really fancy, you can also have programs that will include the station elevation as well (This effect is less than 1 second, but in some areas this can be important). Different customs exist in earth science like which reference model is used. There are currently three models in use: PREM (Preliminary Reference Earth Model), IASPEI91 (Int'l Assoc. Seis. Phys. Earth. 1991), and the older J-B (Jeffreys-Bullen). Most people use PREM it seems, but which model you use can affect the timing of arrivals. For example, some models put a discontinuity at around 200 km depth, and others don't. This discontinuity may reflect deep continental roots under older cratons. Anyways, the two former models are given roughly below. It is interesting to plot one against the other using one of the parameters to see how the two models give different interpretations. In the following, it may be obvious, but I might as well state it: depth= distance from surface density=mass/unit volume vp= P-wave velocity vs= S-wave velocity Qp= Q factor for P-waves (attenuation) Qs= Q factor for S-waves (attenuation) This is the IASPEI91 model: depth density vp vs Qp Qs Junk 0.00 2.72000 5.80000 3.36000 1456.00 600.00 0.00000 20.00 2.72000 5.80000 3.36000 1350.00 600.00 0.00000 20.00 2.92000 6.50000 3.75000 1350.00 600.00 0.00000 35.00 2.92000 6.50000 3.75000 1350.00 600.00 0.00000 35.00 3.31980 8.04000 4.47000 1350.00 600.00 0.00000 77.50 3.34550 8.04500 4.48500 195.00 80.00 0.00000 120.00 3.37130 8.05000 4.50000 195.00 80.00 0.00000 165.00 3.39850 8.17500 4.50900 195.00 80.00 0.00000 210.00 3.42580 8.30000 4.51800 362.00 143.00 0.00000 210.00 3.42580 8.30000 4.52200 362.00 143.00 0.00000 260.00 3.45610 8.48250 4.60900 365.00 143.00 0.00000 310.00 3.48640 8.66500 4.69600 367.00 143.00 0.00000 360.00 3.51670 8.84750 4.78300 372.00 143.00 0.00000 410.00 3.54700 9.03000 4.87000 365.00 143.00 0.00000 410.00 3.75570 9.36000 5.07000 365.00 143.00 0.00000 460.00 3.81750 9.52800 5.17600 364.00 143.00 0.00000 510.00 3.87930 9.69600 5.28200 363.00 143.00 0.00000 560.00 3.94100 9.86400 5.38800 362.00 143.00 0.00000 610.00 4.00280 10.03200 5.49400 362.00 143.00 0.00000 660.00 4.06460 10.20000 5.60000 362.00 143.00 0.00000 660.00 4.37140 10.79000 5.95000 759.00 312.00 0.00000 710.00 4.40100 10.92290 6.07970 744.00 312.00 0.00000 760.00 4.43050 11.05580 6.20950 730.00 312.00 0.00000 809.50 4.45960 11.14400 6.24740 737.00 312.00 0.00000 859.00 4.48850 11.23000 6.28410 739.00 312.00 0.00000 908.50 4.51730 11.31400 6.31990 743.00 312.00 0.00000 958.00 4.54590 11.39600 6.35460 745.00 312.00 0.00000 1007.50 4.57440 11.47610 6.38830 750.00 312.00 0.00000 1057.00 4.60280 11.55430 6.42110 752.00 312.00 0.00000 1106.50 4.63100 11.63080 6.45300 755.00 312.00 0.00000 1156.00 4.65910 11.70560 6.48410 757.00 312.00 0.00000 1205.50 4.68700 11.77870 6.51430 761.00 312.00 0.00000 1255.00 4.71480 11.85040 6.54380 763.00 312.00 0.00000 1304.50 4.74240 11.92050 6.57250 766.00 312.00 0.00000 1354.00 4.76990 11.98930 6.60060 768.00 312.00 0.00000 1403.50 4.79730 12.05680 6.62800 770.00 312.00 0.00000 1453.00 4.82450 12.12310 6.65470 772.00 312.00 0.00000 1502.50 4.85150 12.18810 6.68090 775.00 312.00 0.00000 1552.00 4.87850 12.25210 6.70660 777.00 312.00 0.00000 1601.50 4.90520 12.31510 6.73170 779.00 312.00 0.00000 1651.00 4.93190 12.37720 6.75640 781.00 312.00 0.00000 1700.50 4.95840 12.43830 6.78070 784.00 312.00 0.00000 1750.00 4.98470 12.49870 6.80460 786.00 312.00 0.00000 1799.50 5.01090 12.55840 6.82820 788.00 312.00 0.00000 1849.00 5.03700 12.61740 6.85140 790.00 312.00 0.00000 1898.50 5.06290 12.67590 6.87450 792.00 312.00 0.00000 1948.00 5.08870 12.73390 6.89720 793.00 312.00 0.00000 1997.50 5.11430 12.79150 6.91990 795.00 312.00 0.00000 2047.00 5.13980 12.84870 6.94230 797.00 312.00 0.00000 2096.50 5.16520 12.90570 6.96470 799.00 312.00 0.00000 2146.00 5.19040 12.96250 6.98700 801.00 312.00 0.00000 2195.50 5.21540 13.01920 7.00930 803.00 312.00 0.00000 2245.00 5.24030 13.07580 7.03160 805.00 312.00 0.00000 2294.50 5.26510 13.13250 7.05400 807.00 312.00 0.00000 2344.00 5.28980 13.18920 7.07650 809.00 312.00 0.00000 2393.50 5.31420 13.24620 7.09910 811.00 312.00 0.00000 2443.00 5.33860 13.30340 7.12180 813.00 312.00 0.00000 2492.50 5.36280 13.36100 7.14490 815.00 312.00 0.00000 2542.00 5.38690 13.41900 7.16810 817.00 312.00 0.00000 2591.50 5.41080 13.47740 7.19170 819.00 312.00 0.00000 2641.00 5.43450 13.53640 7.21560 820.00 312.00 0.00000 2690.50 5.45820 13.59610 7.23980 822.00 312.00 0.00000 2740.00 5.48170 13.65640 7.26450 823.00 312.00 0.00000 2789.67 5.50510 13.66790 7.27680 826.00 312.00 0.00000 2839.33 5.52840 13.67930 7.28920 826.00 312.00 0.00000 2889.00 5.55150 13.69080 7.30150 826.00 312.00 0.00000 2889.00 9.91450 8.00880 0.00000 57882.00 0.00 0.00000 2939.33 9.99420 8.09630 0.00000 57822.00 0.00 0.00000 2989.66 10.07220 8.18210 0.00000 57822.00 0.00 0.00000 3039.99 10.14850 8.26620 0.00000 57822.00 0.00 0.00000 3090.32 10.22330 8.34860 0.00000 57822.00 0.00 0.00000 3140.66 10.29640 8.42930 0.00000 57822.00 0.00 0.00000 3190.99 10.36790 8.50830 0.00000 57822.00 0.00 0.00000 3241.32 10.43780 8.58560 0.00000 57822.00 0.00 0.00000 3291.65 10.50620 8.66110 0.00000 57822.00 0.00 0.00000 3341.98 10.57310 8.73500 0.00000 57822.00 0.00 0.00000 3392.31 10.63850 8.80720 0.00000 57822.00 0.00 0.00000 3442.64 10.70230 8.87760 0.00000 57822.00 0.00 0.00000 3492.97 10.76470 8.94640 0.00000 57822.00 0.00 0.00000 3543.30 10.82570 9.01340 0.00000 57822.00 0.00 0.00000 3593.64 10.88520 9.07870 0.00000 57822.00 0.00 0.00000 3643.97 10.94340 9.14240 0.00000 57822.00 0.00 0.00000 3694.30 11.00010 9.20430 0.00000 57822.00 0.00 0.00000 3744.63 11.05550 9.26450 0.00000 57822.00 0.00 0.00000 3794.96 11.10950 9.32300 0.00000 57822.00 0.00 0.00000 3845.29 11.16230 9.37980 0.00000 57822.00 0.00 0.00000 3895.62 11.21370 9.43490 0.00000 57822.00 0.00 0.00000 3945.95 11.26390 9.48830 0.00000 57822.00 0.00 0.00000 3996.28 11.31270 9.54000 0.00000 57822.00 0.00 0.00000 4046.62 11.36040 9.59000 0.00000 57822.00 0.00 0.00000 4096.95 11.40690 9.63830 0.00000 57822.00 0.00 0.00000 4147.28 11.45210 9.68480 0.00000 57822.00 0.00 0.00000 4197.61 11.49620 9.72970 0.00000 57822.00 0.00 0.00000 4247.94 11.53910 9.77280 0.00000 57822.00 0.00 0.00000 4298.27 11.58090 9.81430 0.00000 57822.00 0.00 0.00000 4348.60 11.62160 9.85400 0.00000 57822.00 0.00 0.00000 4398.93 11.66120 9.89200 0.00000 57822.00 0.00 0.00000 4449.26 11.69980 9.92840 0.00000 57822.00 0.00 0.00000 4499.60 11.73730 9.96300 0.00000 57822.00 0.00 0.00000 4549.93 11.77370 9.99590 0.00000 57822.00 0.00 0.00000 4600.26 11.80920 10.02710 0.00000 57822.00 0.00 0.00000 4650.59 11.84370 10.05660 0.00000 57822.00 0.00 0.00000 4700.92 11.87720 10.08440 0.00000 57822.00 0.00 0.00000 4751.25 11.90980 10.11050 0.00000 57822.00 0.00 0.00000 4801.58 11.94140 10.13490 0.00000 57822.00 0.00 0.00000 4851.91 11.97220 10.15760 0.00000 57822.00 0.00 0.00000 4902.24 12.00210 10.17850 0.00000 57822.00 0.00 0.00000 4952.58 12.03110 10.19780 0.00000 57822.00 0.00 0.00000 5002.91 12.05930 10.21540 0.00000 57822.00 0.00 0.00000 5053.24 12.08670 10.23120 0.00000 57822.00 0.00 0.00000 5103.57 12.11330 10.24540 0.00000 57822.00 0.00 0.00000 5153.90 12.13910 10.25780 0.00000 57882.00 0.00 0.00000 5153.90 12.70370 11.09140 3.43850 445.00 85.00 0.00000 5204.61 12.72890 11.10360 3.44880 444.00 85.00 0.00000 5255.32 12.75300 11.11530 3.45870 443.00 85.00 0.00000 5306.04 12.77600 11.12650 3.46810 441.00 85.00 0.00000 5356.75 12.79800 11.13710 3.47700 440.00 85.00 0.00000 5407.46 12.81880 11.14720 3.48560 439.00 85.00 0.00000 5458.17 12.83870 11.15680 3.49370 438.00 85.00 0.00000 5508.89 12.85740 11.16590 3.50130 437.00 85.00 0.00000 5559.60 12.87510 11.17450 3.50850 436.00 85.00 0.00000 5610.31 12.89170 11.18250 3.51530 436.00 85.00 0.00000 5661.02 12.90720 11.19010 3.52170 435.00 85.00 0.00000 5711.74 12.92170 11.19710 3.52760 434.00 85.00 0.00000 5762.45 12.93510 11.20360 3.53300 434.00 85.00 0.00000 5813.16 12.94740 11.20950 3.53810 433.00 85.00 0.00000 5863.87 12.95860 11.21500 3.54270 433.00 85.00 0.00000 5914.59 12.96880 11.21990 3.54680 432.00 85.00 0.00000 5965.30 12.97790 11.22430 3.55050 432.00 85.00 0.00000 6016.01 12.98590 11.22820 3.55380 432.00 85.00 0.00000 6066.72 12.99290 11.23160 3.55670 432.00 85.00 0.00000 6117.44 12.99880 11.23450 3.55910 431.00 85.00 0.00000 6168.15 13.00360 11.23680 3.56100 431.00 85.00 0.00000 6218.86 13.00740 11.23860 3.56260 431.00 85.00 0.00000 6269.57 13.01000 11.23990 3.56370 431.00 85.00 0.00000 6320.29 13.01170 11.24070 3.56430 0.00 0.00 0.00000 6371.00 13.01220 11.24090 3.56450 0.00 0.00 0.00000 This is the PREM model: 0.00 2.60000 5.80000 3.20000 1456.00 600.00 0.00000 15.00 2.90000 6.80000 3.90000 1350.00 600.00 0.00000 24.40 2.90000 6.80000 3.90000 1350.00 600.00 0.00000 24.40 3.38076 8.11061 4.49094 1446.00 600.00 0.00000 40.00 3.37906 8.10119 4.48486 1446.00 600.00 0.00000 60.00 3.37688 8.08907 4.47715 1447.00 600.00 0.00000 80.00 3.37471 8.07689 4.46954 1447.00 600.00 0.00000 80.00 3.37471 8.07688 4.46953 195.00 80.00 0.00000 115.00 3.37091 8.05540 4.45643 195.00 80.00 0.00000 150.00 3.36710 8.03370 4.44361 195.00 80.00 0.00000 185.00 3.36330 8.01180 4.43108 195.00 80.00 0.00000 220.00 3.35950 7.98970 4.41885 195.00 80.00 0.00000 220.00 3.43578 8.55896 4.64391 362.00 143.00 0.00000 265.00 3.46264 8.64552 4.67540 365.00 143.00 0.00000 310.00 3.48951 8.73209 4.70690 367.00 143.00 0.00000 355.00 3.51639 8.81867 4.73840 370.00 143.00 0.00000 400.00 3.54325 8.90522 4.76989 372.00 143.00 0.00000 400.00 3.72378 9.13397 4.93259 366.00 143.00 0.00000 450.00 3.78678 9.38990 5.07842 365.00 143.00 0.00000 500.00 3.84980 9.64588 5.22428 364.00 143.00 0.00000 550.00 3.91282 9.90185 5.37014 363.00 143.00 0.00000 600.00 3.97584 10.15782 5.51602 362.00 143.00 0.00000 635.00 3.98399 10.21203 5.54311 362.00 143.00 0.00000 670.00 3.99214 10.26662 5.57020 362.00 143.00 0.00000 670.00 4.38071 10.75131 5.94508 759.00 312.00 0.00000 721.00 4.41241 10.91005 6.09418 744.00 312.00 0.00000 771.00 4.44317 11.06557 6.24046 730.00 312.00 0.00000 871.00 4.50372 11.24490 6.31091 737.00 312.00 0.00000 971.00 4.56307 11.41560 6.37813 743.00 312.00 0.00000 1071.00 4.62129 11.57828 6.44232 750.00 312.00 0.00000 1171.00 4.67844 11.73357 6.50370 755.00 312.00 0.00000 1271.00 4.73460 11.88209 6.56250 761.00 312.00 0.00000 1371.00 4.78983 12.02445 6.61891 766.00 312.00 0.00000 1471.00 4.84422 12.16126 6.67317 770.00 312.00 0.00000 1571.00 4.89783 12.29316 6.72548 775.00 312.00 0.00000 1671.00 4.95073 12.42075 6.77606 779.00 312.00 0.00000 1771.00 5.00299 12.54466 6.82512 784.00 312.00 0.00000 1871.00 5.05469 12.66550 6.87289 788.00 312.00 0.00000 1971.00 5.10590 12.78389 6.91957 792.00 312.00 0.00000 2071.00 5.15669 12.90045 6.96538 795.00 312.00 0.00000 2171.00 5.20713 13.01579 7.01053 799.00 312.00 0.00000 2271.00 5.25729 13.13055 7.05525 803.00 312.00 0.00000 2371.00 5.30724 13.24532 7.09974 807.00 312.00 0.00000 2471.00 5.35706 13.36074 7.14423 811.00 312.00 0.00000 2571.00 5.40681 13.47742 7.18892 815.00 312.00 0.00000 2671.00 5.45657 13.59597 7.23403 819.00 312.00 0.00000 2741.00 5.49145 13.68041 7.26597 822.00 312.00 0.00000 2771.00 5.50642 13.68753 7.26575 823.00 312.00 0.00000 2871.00 5.55641 13.71168 7.26486 826.00 312.00 0.00000 2891.00 5.56645 13.71660 7.26466 826.00 312.00 0.00000 2891.00 9.90349 8.06482 0.00000 57882.00 0.00 0.00000 2971.00 10.02940 8.19939 0.00000 57822.00 0.00 0.00000 3071.00 10.18134 8.36019 0.00000 57822.00 0.00 0.00000 3171.00 10.32726 8.51298 0.00000 57822.00 0.00 0.00000 3271.00 10.46727 8.65805 0.00000 57822.00 0.00 0.00000 3371.00 10.60152 8.79573 0.00000 57822.00 0.00 0.00000 3471.00 10.73012 8.92632 0.00000 57822.00 0.00 0.00000 3571.00 10.85321 9.05015 0.00000 57822.00 0.00 0.00000 3671.00 10.97091 9.16752 0.00000 57822.00 0.00 0.00000 3771.00 11.08335 9.27876 0.00000 57822.00 0.00 0.00000 3871.00 11.19067 9.38418 0.00000 57822.00 0.00 0.00000 3971.00 11.29298 9.48409 0.00000 57822.00 0.00 0.00000 4071.00 11.39042 9.57881 0.00000 57822.00 0.00 0.00000 4171.00 11.48311 9.66865 0.00000 57822.00 0.00 0.00000 4271.00 11.57119 9.75393 0.00000 57822.00 0.00 0.00000 4371.00 11.65478 9.83496 0.00000 57822.00 0.00 0.00000 4471.00 11.73401 9.91206 0.00000 57822.00 0.00 0.00000 4571.00 11.80900 9.98554 0.00000 57822.00 0.00 0.00000 4671.00 11.87990 10.05572 0.00000 57822.00 0.00 0.00000 4771.00 11.94682 10.12291 0.00000 57822.00 0.00 0.00000 4871.00 12.00989 10.18743 0.00000 57822.00 0.00 0.00000 4971.00 12.06924 10.24959 0.00000 57822.00 0.00 0.00000 5071.00 12.12500 10.30971 0.00000 57822.00 0.00 0.00000 5149.50 12.16634 10.35568 0.00000 57822.00 0.00 0.00000 5149.50 12.76360 11.02827 3.50432 445.00 85.00 0.00000 5171.00 12.77493 11.03643 3.51002 445.00 85.00 0.00000 5271.00 12.82501 11.07249 3.53522 443.00 85.00 0.00000 5371.00 12.87073 11.10542 3.55823 440.00 85.00 0.00000 5471.00 12.91211 11.13521 3.57905 439.00 85.00 0.00000 5571.00 12.94912 11.16186 3.59767 437.00 85.00 0.00000 5671.00 12.98178 11.18538 3.61411 436.00 85.00 0.00000 5771.00 13.01009 11.20576 3.62835 434.00 85.00 0.00000 5871.00 13.03404 11.22301 3.64041 433.00 85.00 0.00000 5971.00 13.05364 11.23712 3.65027 432.00 85.00 0.00000 6071.00 13.06888 11.24809 3.65794 432.00 85.00 0.00000 6171.00 13.07977 11.25593 3.66342 431.00 85.00 0.00000 6271.00 13.08630 11.26064 3.66670 431.00 85.00 0.00000 The next step to getting an accurate representation of what you see on your seismogram is a method called "synthetic seismograms" which uses a finite-element modelling technique to generate a seismogram based on the information you have given, like the earth model, source mechanism, and any departures from the model between the station and the quake. The earthquake source tells you how the elastic waves looked as they propagated out. There are characteristic radiation patterns for waves leaving an ideal fault (double couple) that are also used. ****************************************************************************** John Hernlund E-mail: 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 From: Dick Webb Subject: Re: Reading Seismograms Date: Fri, 12 Mar 1999 13:30:41 -0500 John, Thanks for the information about earth models. My question is a tad more basic. When confronted with a seismogram what is the best way to approach making picks IF YOU DON'T KNOW THE HYPOCENTER. Are there characteristic shapes and relationships that would let one determine a P from a Pp and even something so simple as an S wave. After all they must have used the eyeball approach before the days of the internet or telemetry. Dick At 10:42 AM 3/12/99 -0700, you wrote: >On Fri, 12 Mar 1999, Dick Webb wrote: >> For the past few years, I've been using "Earthquake Interpretations A >> manual for Reading Seismograms" by Simon as an aid in reading seismograms. >> I've not been able to locate other guides. Do you know of any books or >> references that give good guidance on making the proper picks. >> Particularly teleseisms. > >Dick, > I think most people do things similar to Larry's arrival time picks by >plugging in an epicentral distance, depth, and a reference earth model. The >reference earth model is itself an inversion of arrival times averaged for >many events. If you wanted to get really fancy, you can also have programs >that will include the station elevation as well (This effect is less than 1 >second, but in some areas this can be important). Different customs exist in >earth science like which reference model is used. There are currently three >models in use: PREM (Preliminary Reference Earth Model), IASPEI91 (Int'l >Assoc. Seis. Phys. Earth. 1991), and the older J-B (Jeffreys-Bullen). Most >people use PREM it seems, but which model you use can affect the timing of >arrivals. For example, some models put a discontinuity at around 200 km >depth, and others don't. This discontinuity may reflect deep continental >roots under older cratons. Anyways, the two former models are given roughly >below. It is interesting to plot one against the other using one of the >parameters to see how the two models give different interpretations. In the >following, it may be obvious, but I might as well state it: > >depth= distance from surface >density=mass/unit volume >vp= P-wave velocity >vs= S-wave velocity >Qp= Q factor for P-waves (attenuation) >Qs= Q factor for S-waves (attenuation) > >This is the IASPEI91 model: > > depth density vp vs Qp Qs Junk > 0.00 2.72000 5.80000 3.36000 1456.00 600.00 0.00000 > 20.00 2.72000 5.80000 3.36000 1350.00 600.00 0.00000 > 20.00 2.92000 6.50000 3.75000 1350.00 600.00 0.00000 > 35.00 2.92000 6.50000 3.75000 1350.00 600.00 0.00000 > 35.00 3.31980 8.04000 4.47000 1350.00 600.00 0.00000 > 77.50 3.34550 8.04500 4.48500 195.00 80.00 0.00000 > 120.00 3.37130 8.05000 4.50000 195.00 80.00 0.00000 > 165.00 3.39850 8.17500 4.50900 195.00 80.00 0.00000 > 210.00 3.42580 8.30000 4.51800 362.00 143.00 0.00000 > 210.00 3.42580 8.30000 4.52200 362.00 143.00 0.00000 > 260.00 3.45610 8.48250 4.60900 365.00 143.00 0.00000 > 310.00 3.48640 8.66500 4.69600 367.00 143.00 0.00000 > 360.00 3.51670 8.84750 4.78300 372.00 143.00 0.00000 > 410.00 3.54700 9.03000 4.87000 365.00 143.00 0.00000 > 410.00 3.75570 9.36000 5.07000 365.00 143.00 0.00000 > 460.00 3.81750 9.52800 5.17600 364.00 143.00 0.00000 > 510.00 3.87930 9.69600 5.28200 363.00 143.00 0.00000 > 560.00 3.94100 9.86400 5.38800 362.00 143.00 0.00000 > 610.00 4.00280 10.03200 5.49400 362.00 143.00 0.00000 > 660.00 4.06460 10.20000 5.60000 362.00 143.00 0.00000 > 660.00 4.37140 10.79000 5.95000 759.00 312.00 0.00000 > 710.00 4.40100 10.92290 6.07970 744.00 312.00 0.00000 > 760.00 4.43050 11.05580 6.20950 730.00 312.00 0.00000 > 809.50 4.45960 11.14400 6.24740 737.00 312.00 0.00000 > 859.00 4.48850 11.23000 6.28410 739.00 312.00 0.00000 > 908.50 4.51730 11.31400 6.31990 743.00 312.00 0.00000 > 958.00 4.54590 11.39600 6.35460 745.00 312.00 0.00000 > 1007.50 4.57440 11.47610 6.38830 750.00 312.00 0.00000 > 1057.00 4.60280 11.55430 6.42110 752.00 312.00 0.00000 > 1106.50 4.63100 11.63080 6.45300 755.00 312.00 0.00000 > 1156.00 4.65910 11.70560 6.48410 757.00 312.00 0.00000 > 1205.50 4.68700 11.77870 6.51430 761.00 312.00 0.00000 > 1255.00 4.71480 11.85040 6.54380 763.00 312.00 0.00000 > 1304.50 4.74240 11.92050 6.57250 766.00 312.00 0.00000 > 1354.00 4.76990 11.98930 6.60060 768.00 312.00 0.00000 > 1403.50 4.79730 12.05680 6.62800 770.00 312.00 0.00000 > 1453.00 4.82450 12.12310 6.65470 772.00 312.00 0.00000 > 1502.50 4.85150 12.18810 6.68090 775.00 312.00 0.00000 > 1552.00 4.87850 12.25210 6.70660 777.00 312.00 0.00000 > 1601.50 4.90520 12.31510 6.73170 779.00 312.00 0.00000 > 1651.00 4.93190 12.37720 6.75640 781.00 312.00 0.00000 > 1700.50 4.95840 12.43830 6.78070 784.00 312.00 0.00000 > 1750.00 4.98470 12.49870 6.80460 786.00 312.00 0.00000 > 1799.50 5.01090 12.55840 6.82820 788.00 312.00 0.00000 > 1849.00 5.03700 12.61740 6.85140 790.00 312.00 0.00000 > 1898.50 5.06290 12.67590 6.87450 792.00 312.00 0.00000 > 1948.00 5.08870 12.73390 6.89720 793.00 312.00 0.00000 > 1997.50 5.11430 12.79150 6.91990 795.00 312.00 0.00000 > 2047.00 5.13980 12.84870 6.94230 797.00 312.00 0.00000 > 2096.50 5.16520 12.90570 6.96470 799.00 312.00 0.00000 > 2146.00 5.19040 12.96250 6.98700 801.00 312.00 0.00000 > 2195.50 5.21540 13.01920 7.00930 803.00 312.00 0.00000 > 2245.00 5.24030 13.07580 7.03160 805.00 312.00 0.00000 > 2294.50 5.26510 13.13250 7.05400 807.00 312.00 0.00000 > 2344.00 5.28980 13.18920 7.07650 809.00 312.00 0.00000 > 2393.50 5.31420 13.24620 7.09910 811.00 312.00 0.00000 > 2443.00 5.33860 13.30340 7.12180 813.00 312.00 0.00000 > 2492.50 5.36280 13.36100 7.14490 815.00 312.00 0.00000 > 2542.00 5.38690 13.41900 7.16810 817.00 312.00 0.00000 > 2591.50 5.41080 13.47740 7.19170 819.00 312.00 0.00000 > 2641.00 5.43450 13.53640 7.21560 820.00 312.00 0.00000 > 2690.50 5.45820 13.59610 7.23980 822.00 312.00 0.00000 > 2740.00 5.48170 13.65640 7.26450 823.00 312.00 0.00000 > 2789.67 5.50510 13.66790 7.27680 826.00 312.00 0.00000 > 2839.33 5.52840 13.67930 7.28920 826.00 312.00 0.00000 > 2889.00 5.55150 13.69080 7.30150 826.00 312.00 0.00000 > 2889.00 9.91450 8.00880 0.00000 57882.00 0.00 0.00000 > 2939.33 9.99420 8.09630 0.00000 57822.00 0.00 0.00000 > 2989.66 10.07220 8.18210 0.00000 57822.00 0.00 0.00000 > 3039.99 10.14850 8.26620 0.00000 57822.00 0.00 0.00000 > 3090.32 10.22330 8.34860 0.00000 57822.00 0.00 0.00000 > 3140.66 10.29640 8.42930 0.00000 57822.00 0.00 0.00000 > 3190.99 10.36790 8.50830 0.00000 57822.00 0.00 0.00000 > 3241.32 10.43780 8.58560 0.00000 57822.00 0.00 0.00000 > 3291.65 10.50620 8.66110 0.00000 57822.00 0.00 0.00000 > 3341.98 10.57310 8.73500 0.00000 57822.00 0.00 0.00000 > 3392.31 10.63850 8.80720 0.00000 57822.00 0.00 0.00000 > 3442.64 10.70230 8.87760 0.00000 57822.00 0.00 0.00000 > 3492.97 10.76470 8.94640 0.00000 57822.00 0.00 0.00000 > 3543.30 10.82570 9.01340 0.00000 57822.00 0.00 0.00000 > 3593.64 10.88520 9.07870 0.00000 57822.00 0.00 0.00000 > 3643.97 10.94340 9.14240 0.00000 57822.00 0.00 0.00000 > 3694.30 11.00010 9.20430 0.00000 57822.00 0.00 0.00000 > 3744.63 11.05550 9.26450 0.00000 57822.00 0.00 0.00000 > 3794.96 11.10950 9.32300 0.00000 57822.00 0.00 0.00000 > 3845.29 11.16230 9.37980 0.00000 57822.00 0.00 0.00000 > 3895.62 11.21370 9.43490 0.00000 57822.00 0.00 0.00000 > 3945.95 11.26390 9.48830 0.00000 57822.00 0.00 0.00000 > 3996.28 11.31270 9.54000 0.00000 57822.00 0.00 0.00000 > 4046.62 11.36040 9.59000 0.00000 57822.00 0.00 0.00000 > 4096.95 11.40690 9.63830 0.00000 57822.00 0.00 0.00000 > 4147.28 11.45210 9.68480 0.00000 57822.00 0.00 0.00000 > 4197.61 11.49620 9.72970 0.00000 57822.00 0.00 0.00000 > 4247.94 11.53910 9.77280 0.00000 57822.00 0.00 0.00000 > 4298.27 11.58090 9.81430 0.00000 57822.00 0.00 0.00000 > 4348.60 11.62160 9.85400 0.00000 57822.00 0.00 0.00000 > 4398.93 11.66120 9.89200 0.00000 57822.00 0.00 0.00000 > 4449.26 11.69980 9.92840 0.00000 57822.00 0.00 0.00000 > 4499.60 11.73730 9.96300 0.00000 57822.00 0.00 0.00000 > 4549.93 11.77370 9.99590 0.00000 57822.00 0.00 0.00000 > 4600.26 11.80920 10.02710 0.00000 57822.00 0.00 0.00000 > 4650.59 11.84370 10.05660 0.00000 57822.00 0.00 0.00000 > 4700.92 11.87720 10.08440 0.00000 57822.00 0.00 0.00000 > 4751.25 11.90980 10.11050 0.00000 57822.00 0.00 0.00000 > 4801.58 11.94140 10.13490 0.00000 57822.00 0.00 0.00000 > 4851.91 11.97220 10.15760 0.00000 57822.00 0.00 0.00000 > 4902.24 12.00210 10.17850 0.00000 57822.00 0.00 0.00000 > 4952.58 12.03110 10.19780 0.00000 57822.00 0.00 0.00000 > 5002.91 12.05930 10.21540 0.00000 57822.00 0.00 0.00000 > 5053.24 12.08670 10.23120 0.00000 57822.00 0.00 0.00000 > 5103.57 12.11330 10.24540 0.00000 57822.00 0.00 0.00000 > 5153.90 12.13910 10.25780 0.00000 57882.00 0.00 0.00000 > 5153.90 12.70370 11.09140 3.43850 445.00 85.00 0.00000 > 5204.61 12.72890 11.10360 3.44880 444.00 85.00 0.00000 > 5255.32 12.75300 11.11530 3.45870 443.00 85.00 0.00000 > 5306.04 12.77600 11.12650 3.46810 441.00 85.00 0.00000 > 5356.75 12.79800 11.13710 3.47700 440.00 85.00 0.00000 > 5407.46 12.81880 11.14720 3.48560 439.00 85.00 0.00000 > 5458.17 12.83870 11.15680 3.49370 438.00 85.00 0.00000 > 5508.89 12.85740 11.16590 3.50130 437.00 85.00 0.00000 > 5559.60 12.87510 11.17450 3.50850 436.00 85.00 0.00000 > 5610.31 12.89170 11.18250 3.51530 436.00 85.00 0.00000 > 5661.02 12.90720 11.19010 3.52170 435.00 85.00 0.00000 > 5711.74 12.92170 11.19710 3.52760 434.00 85.00 0.00000 > 5762.45 12.93510 11.20360 3.53300 434.00 85.00 0.00000 > 5813.16 12.94740 11.20950 3.53810 433.00 85.00 0.00000 > 5863.87 12.95860 11.21500 3.54270 433.00 85.00 0.00000 > 5914.59 12.96880 11.21990 3.54680 432.00 85.00 0.00000 > 5965.30 12.97790 11.22430 3.55050 432.00 85.00 0.00000 > 6016.01 12.98590 11.22820 3.55380 432.00 85.00 0.00000 > 6066.72 12.99290 11.23160 3.55670 432.00 85.00 0.00000 > 6117.44 12.99880 11.23450 3.55910 431.00 85.00 0.00000 > 6168.15 13.00360 11.23680 3.56100 431.00 85.00 0.00000 > 6218.86 13.00740 11.23860 3.56260 431.00 85.00 0.00000 > 6269.57 13.01000 11.23990 3.56370 431.00 85.00 0.00000 > 6320.29 13.01170 11.24070 3.56430 0.00 0.00 0.00000 > 6371.00 13.01220 11.24090 3.56450 0.00 0.00 0.00000 > >This is the PREM model: > > 0.00 2.60000 5.80000 3.20000 1456.00 600.00 0.00000 > 15.00 2.90000 6.80000 3.90000 1350.00 600.00 0.00000 > 24.40 2.90000 6.80000 3.90000 1350.00 600.00 0.00000 > 24.40 3.38076 8.11061 4.49094 1446.00 600.00 0.00000 > 40.00 3.37906 8.10119 4.48486 1446.00 600.00 0.00000 > 60.00 3.37688 8.08907 4.47715 1447.00 600.00 0.00000 > 80.00 3.37471 8.07689 4.46954 1447.00 600.00 0.00000 > 80.00 3.37471 8.07688 4.46953 195.00 80.00 0.00000 > 115.00 3.37091 8.05540 4.45643 195.00 80.00 0.00000 > 150.00 3.36710 8.03370 4.44361 195.00 80.00 0.00000 > 185.00 3.36330 8.01180 4.43108 195.00 80.00 0.00000 > 220.00 3.35950 7.98970 4.41885 195.00 80.00 0.00000 > 220.00 3.43578 8.55896 4.64391 362.00 143.00 0.00000 > 265.00 3.46264 8.64552 4.67540 365.00 143.00 0.00000 > 310.00 3.48951 8.73209 4.70690 367.00 143.00 0.00000 > 355.00 3.51639 8.81867 4.73840 370.00 143.00 0.00000 > 400.00 3.54325 8.90522 4.76989 372.00 143.00 0.00000 > 400.00 3.72378 9.13397 4.93259 366.00 143.00 0.00000 > 450.00 3.78678 9.38990 5.07842 365.00 143.00 0.00000 > 500.00 3.84980 9.64588 5.22428 364.00 143.00 0.00000 > 550.00 3.91282 9.90185 5.37014 363.00 143.00 0.00000 > 600.00 3.97584 10.15782 5.51602 362.00 143.00 0.00000 > 635.00 3.98399 10.21203 5.54311 362.00 143.00 0.00000 > 670.00 3.99214 10.26662 5.57020 362.00 143.00 0.00000 > 670.00 4.38071 10.75131 5.94508 759.00 312.00 0.00000 > 721.00 4.41241 10.91005 6.09418 744.00 312.00 0.00000 > 771.00 4.44317 11.06557 6.24046 730.00 312.00 0.00000 > 871.00 4.50372 11.24490 6.31091 737.00 312.00 0.00000 > 971.00 4.56307 11.41560 6.37813 743.00 312.00 0.00000 > 1071.00 4.62129 11.57828 6.44232 750.00 312.00 0.00000 > 1171.00 4.67844 11.73357 6.50370 755.00 312.00 0.00000 > 1271.00 4.73460 11.88209 6.56250 761.00 312.00 0.00000 > 1371.00 4.78983 12.02445 6.61891 766.00 312.00 0.00000 > 1471.00 4.84422 12.16126 6.67317 770.00 312.00 0.00000 > 1571.00 4.89783 12.29316 6.72548 775.00 312.00 0.00000 > 1671.00 4.95073 12.42075 6.77606 779.00 312.00 0.00000 > 1771.00 5.00299 12.54466 6.82512 784.00 312.00 0.00000 > 1871.00 5.05469 12.66550 6.87289 788.00 312.00 0.00000 > 1971.00 5.10590 12.78389 6.91957 792.00 312.00 0.00000 > 2071.00 5.15669 12.90045 6.96538 795.00 312.00 0.00000 > 2171.00 5.20713 13.01579 7.01053 799.00 312.00 0.00000 > 2271.00 5.25729 13.13055 7.05525 803.00 312.00 0.00000 > 2371.00 5.30724 13.24532 7.09974 807.00 312.00 0.00000 > 2471.00 5.35706 13.36074 7.14423 811.00 312.00 0.00000 > 2571.00 5.40681 13.47742 7.18892 815.00 312.00 0.00000 > 2671.00 5.45657 13.59597 7.23403 819.00 312.00 0.00000 > 2741.00 5.49145 13.68041 7.26597 822.00 312.00 0.00000 > 2771.00 5.50642 13.68753 7.26575 823.00 312.00 0.00000 > 2871.00 5.55641 13.71168 7.26486 826.00 312.00 0.00000 > 2891.00 5.56645 13.71660 7.26466 826.00 312.00 0.00000 > 2891.00 9.90349 8.06482 0.00000 57882.00 0.00 0.00000 > 2971.00 10.02940 8.19939 0.00000 57822.00 0.00 0.00000 > 3071.00 10.18134 8.36019 0.00000 57822.00 0.00 0.00000 > 3171.00 10.32726 8.51298 0.00000 57822.00 0.00 0.00000 > 3271.00 10.46727 8.65805 0.00000 57822.00 0.00 0.00000 > 3371.00 10.60152 8.79573 0.00000 57822.00 0.00 0.00000 > 3471.00 10.73012 8.92632 0.00000 57822.00 0.00 0.00000 > 3571.00 10.85321 9.05015 0.00000 57822.00 0.00 0.00000 > 3671.00 10.97091 9.16752 0.00000 57822.00 0.00 0.00000 > 3771.00 11.08335 9.27876 0.00000 57822.00 0.00 0.00000 > 3871.00 11.19067 9.38418 0.00000 57822.00 0.00 0.00000 > 3971.00 11.29298 9.48409 0.00000 57822.00 0.00 0.00000 > 4071.00 11.39042 9.57881 0.00000 57822.00 0.00 0.00000 > 4171.00 11.48311 9.66865 0.00000 57822.00 0.00 0.00000 > 4271.00 11.57119 9.75393 0.00000 57822.00 0.00 0.00000 > 4371.00 11.65478 9.83496 0.00000 57822.00 0.00 0.00000 > 4471.00 11.73401 9.91206 0.00000 57822.00 0.00 0.00000 > 4571.00 11.80900 9.98554 0.00000 57822.00 0.00 0.00000 > 4671.00 11.87990 10.05572 0.00000 57822.00 0.00 0.00000 > 4771.00 11.94682 10.12291 0.00000 57822.00 0.00 0.00000 > 4871.00 12.00989 10.18743 0.00000 57822.00 0.00 0.00000 > 4971.00 12.06924 10.24959 0.00000 57822.00 0.00 0.00000 > 5071.00 12.12500 10.30971 0.00000 57822.00 0.00 0.00000 > 5149.50 12.16634 10.35568 0.00000 57822.00 0.00 0.00000 > 5149.50 12.76360 11.02827 3.50432 445.00 85.00 0.00000 > 5171.00 12.77493 11.03643 3.51002 445.00 85.00 0.00000 > 5271.00 12.82501 11.07249 3.53522 443.00 85.00 0.00000 > 5371.00 12.87073 11.10542 3.55823 440.00 85.00 0.00000 > 5471.00 12.91211 11.13521 3.57905 439.00 85.00 0.00000 > 5571.00 12.94912 11.16186 3.59767 437.00 85.00 0.00000 > 5671.00 12.98178 11.18538 3.61411 436.00 85.00 0.00000 > 5771.00 13.01009 11.20576 3.62835 434.00 85.00 0.00000 > 5871.00 13.03404 11.22301 3.64041 433.00 85.00 0.00000 > 5971.00 13.05364 11.23712 3.65027 432.00 85.00 0.00000 > 6071.00 13.06888 11.24809 3.65794 432.00 85.00 0.00000 > 6171.00 13.07977 11.25593 3.66342 431.00 85.00 0.00000 > 6271.00 13.08630 11.26064 3.66670 431.00 85.00 0.00000 > > > The next step to getting an accurate representation of what you see on your >seismogram is a method called "synthetic seismograms" which uses a >finite-element modelling technique to generate a seismogram based on the >information you have given, like the earth model, source mechanism, and any >departures from the model between the station and the quake. The earthquake >source tells you how the elastic waves looked as they propagated out. There >are characteristic radiation patterns for waves leaving an ideal fault (double >couple) that are also used. > >****************************************************************************** > > John Hernlund > E-mail: 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 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: Reading Seismograms Date: Fri, 12 Mar 1999 15:37:01 -0700 (MST) On Fri, 12 Mar 1999, Dick Webb wrote: > John, > Thanks for the information about earth models. My question is a tad more > basic. When confronted with a seismogram what is the best way to approach > making picks IF YOU DON'T KNOW THE HYPOCENTER. Are there characteristic > shapes and relationships that would let one determine a P from a Pp and > even something so simple as an S wave. After all they must have used the > eyeball approach before the days of the internet or telemetry. Dick, Well, reading seismograms really well involves an intimate aquaintance with wave behavior and the earth models. The successful interpretation must be consistent with all of the facts. Keep in mind that interpreting seismograms is very difficult! I'll outline techniques and general rules to use to start interpreting these things, but beyond that I am not that good at interpreting these things myself! 1- Never use the onset of surface waves for your travel times. Surface waves are the largest features on a seismogram, and it is tempting to use them, but their travel paths are complicated by changes in the crust and upper mantle. 2- You will never know for sure if your arrivals are S or P type unless you have at least two well-oriented seismographs and in general you must have all three components of ground motion and have instruments that have the same ground response. 3- If you have three components, then you can make vector plots (also called particle motion plots) of two component directions for any direction you want by using linear algebra (rotation matrix). These will help you understand what direction the ground was moving in three dimensions. A first P-wave arrival will always produce a particle motion that points down back toward the epicenter. The S-wave motions will in general be nearly perpendicular to the P-wave direction. If the first P-wave arrival is up and down motion then the epicenter is on the opposite side of the Earth. If it is nearly horizontal then the earthquake is fairly close. 4- Waves do not leave the earthquake source nicely. The fault that generated the quake probably did not move smoothly, but rather in small steps and jumps. Also, the fault is not a single point but a planar feature, so that waves are spread out. This means that the nice wiggles we would normally expect on a seismogram are actually very chaotic a strange things. 5- Waves that have reflected off some boundary may go through several reflections instead of one large one. This will give these arrivals a complicated pattern and more than one wavelet. 6- Waves refract and also convert to other forms when passing through sharp discontinuities like the moho. There will be an S and a P wave generated and refracted through a boundary like the moho, which makes the seismograms near any arrival more complex. 7- Multiple reflections can occur in upper layers that may look like separate wave arrivals but are really only an earlier arrival still bouncing around. 8- Noise...need I say more. The only basic thing you can really do is compare your seismogram with an arrival time plot to look for a match in patterns. If you have a low noise location on good bedrock in a fairly homogeneous portion of a continent then you will probably be able to do most of what you want. Another idea is to get a program that will generate phase arrivals for a given distance and depth. I have a fortran code for this if you want. Then start studying seismograms phase by phase. For instance, go through many records looking only at SS, or maybe look for pP in the deeper focus quakes...things like that. It is very difficult to do all this, and there are no simple answers... ****************************************************************************** John Hernlund E-mail: 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 From: S-T Morrissey Subject: Re: Reading Seismograms Date: Fri, 12 Mar 1999 20:04:00 -0600 (CST) Dick: The document you need is the: "Principles Underlying the Interpretation of Seismograms" Special publication 254, revised (1966) edition, Prepared by Frank Neumann, Geophysicist, Coast and Geodetic Survey U.S. govt. printing office, Wash, DC, 20402, This 50 page report also includes a set of travel-time tables for 4 different depths as well as sample seismograms. It is the definitive document for reading analog seismogram records. But, as has been pointed out, only experience can bring familiarity with the data. After 30 years of reading seismograms, I can generally tell whether and event is in Alaska or South America at first glance; we sometimes bet on the guessed location, but sometimes we are thrown way off because of a rare depth phase or whatever. An estimate of the arrival azimuth and a great-circle map of the world centered on the station also helps, since quakes only occurr in seismogenic zones. 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 From: S-T Morrissey Subject: Re: Reading Seismograms Date: Fri, 12 Mar 1999 20:04:00 -0600 (CST) Dick: The document you need is the: "Principles Underlying the Interpretation of Seismograms" Special publication 254, revised (1966) edition, Prepared by Frank Neumann, Geophysicist, Coast and Geodetic Survey U.S. govt. printing office, Wash, DC, 20402, This 50 page report also includes a set of travel-time tables for 4 different depths as well as sample seismograms. It is the definitive document for reading analog seismogram records. But, as has been pointed out, only experience can bring familiarity with the data. After 30 years of reading seismograms, I can generally tell whether and event is in Alaska or South America at first glance; we sometimes bet on the guessed location, but sometimes we are thrown way off because of a rare depth phase or whatever. An estimate of the arrival azimuth and a great-circle map of the world centered on the station also helps, since quakes only occurr in seismogenic zones. 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 From: Brett Nordgren Subject: Re: Hinges and things Date: Fri, 12 Mar 1999 22:03:33 -0500 Charles, Thanks for the references and comments on the Rolamite design. I'll be sure look them up. Turns out some of my other conclusions on the hinge design are .... garbage. There's nothing magic about a 2:1 ratio for the cylinder diameters, most anything works, and the rotational axis is not constant, it moves around a bit as the hinge rotates. The good news is that, the deviation from perfection is quite small. I calculated about .0002" error from a circular arc, at the end of a beam using 0.5" rods, over +/- 8 degrees of rotation. Thanks also to John Lahr, whose comments started me re-thinking the whole hinge thing. Regards, Brett _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: Reading Seismograms Date: Fri, 12 Mar 1999 19:56:40 -0800 Dick $0.02 I think the major phases have different frequenct components. ie I have run a simple program which does an FFT on a moving time window and you can see the P then S then Surface waves arrive. -- Just a little more to aid the eye. Regards Barry Dick Webb wrote: > John, > Thanks for the information about earth models. My question is a tad more > basic. When confronted with a seismogram what is the best way to approach > making picks IF YOU DON'T KNOW THE HYPOCENTER. Are there characteristic > shapes and relationships that would let one determine a P from a Pp and > even something so simple as an S wave. After all they must have used the > eyeball approach before the days of the internet or telemetry. > > Dick > > At 10:42 AM 3/12/99 -0700, you wrote: > >On Fri, 12 Mar 1999, Dick Webb wrote: > >> For the past few years, I've been using "Earthquake Interpretations A > >> manual for Reading Seismograms" by Simon as an aid in reading seismograms. > >> I've not been able to locate other guides. Do you know of any books or > >> references that give good guidance on making the proper picks. > >> Particularly teleseisms. > > > >Dick, > > I think most people do things similar to Larry's arrival time picks by > >plugging in an epicentral distance, depth, and a reference earth model. The > >reference earth model is itself an inversion of arrival times averaged for > >many events. If you wanted to get really fancy, you can also have programs > >that will include the station elevation as well (This effect is less than 1 > >second, but in some areas this can be important). Different customs exist in > >earth science like which reference model is used. There are currently three > >models in use: PREM (Preliminary Reference Earth Model), IASPEI91 (Int'l > >Assoc. Seis. Phys. Earth. 1991), and the older J-B (Jeffreys-Bullen). Most > >people use PREM it seems, but which model you use can affect the timing of > >arrivals. For example, some models put a discontinuity at around 200 km > >depth, and others don't. This discontinuity may reflect deep continental > >roots under older cratons. Anyways, the two former models are given roughly > >below. It is interesting to plot one against the other using one of the > >parameters to see how the two models give different interpretations. In the > >following, it may be obvious, but I might as well state it: > > > >depth= distance from surface > >density=mass/unit volume > >vp= P-wave velocity > >vs= S-wave velocity > >Qp= Q factor for P-waves (attenuation) > >Qs= Q factor for S-waves (attenuation) > > > >This is the IASPEI91 model: > > > > depth density vp vs Qp Qs Junk > > 0.00 2.72000 5.80000 3.36000 1456.00 600.00 0.00000 > > 20.00 2.72000 5.80000 3.36000 1350.00 600.00 0.00000 > > 20.00 2.92000 6.50000 3.75000 1350.00 600.00 0.00000 > > 35.00 2.92000 6.50000 3.75000 1350.00 600.00 0.00000 > > 35.00 3.31980 8.04000 4.47000 1350.00 600.00 0.00000 > > 77.50 3.34550 8.04500 4.48500 195.00 80.00 0.00000 > > 120.00 3.37130 8.05000 4.50000 195.00 80.00 0.00000 > > 165.00 3.39850 8.17500 4.50900 195.00 80.00 0.00000 > > 210.00 3.42580 8.30000 4.51800 362.00 143.00 0.00000 > > 210.00 3.42580 8.30000 4.52200 362.00 143.00 0.00000 > > 260.00 3.45610 8.48250 4.60900 365.00 143.00 0.00000 > > 310.00 3.48640 8.66500 4.69600 367.00 143.00 0.00000 > > 360.00 3.51670 8.84750 4.78300 372.00 143.00 0.00000 > > 410.00 3.54700 9.03000 4.87000 365.00 143.00 0.00000 > > 410.00 3.75570 9.36000 5.07000 365.00 143.00 0.00000 > > 460.00 3.81750 9.52800 5.17600 364.00 143.00 0.00000 > > 510.00 3.87930 9.69600 5.28200 363.00 143.00 0.00000 > > 560.00 3.94100 9.86400 5.38800 362.00 143.00 0.00000 > > 610.00 4.00280 10.03200 5.49400 362.00 143.00 0.00000 > > 660.00 4.06460 10.20000 5.60000 362.00 143.00 0.00000 > > 660.00 4.37140 10.79000 5.95000 759.00 312.00 0.00000 > > 710.00 4.40100 10.92290 6.07970 744.00 312.00 0.00000 > > 760.00 4.43050 11.05580 6.20950 730.00 312.00 0.00000 > > 809.50 4.45960 11.14400 6.24740 737.00 312.00 0.00000 > > 859.00 4.48850 11.23000 6.28410 739.00 312.00 0.00000 > > 908.50 4.51730 11.31400 6.31990 743.00 312.00 0.00000 > > 958.00 4.54590 11.39600 6.35460 745.00 312.00 0.00000 > > 1007.50 4.57440 11.47610 6.38830 750.00 312.00 0.00000 > > 1057.00 4.60280 11.55430 6.42110 752.00 312.00 0.00000 > > 1106.50 4.63100 11.63080 6.45300 755.00 312.00 0.00000 > > 1156.00 4.65910 11.70560 6.48410 757.00 312.00 0.00000 > > 1205.50 4.68700 11.77870 6.51430 761.00 312.00 0.00000 > > 1255.00 4.71480 11.85040 6.54380 763.00 312.00 0.00000 > > 1304.50 4.74240 11.92050 6.57250 766.00 312.00 0.00000 > > 1354.00 4.76990 11.98930 6.60060 768.00 312.00 0.00000 > > 1403.50 4.79730 12.05680 6.62800 770.00 312.00 0.00000 > > 1453.00 4.82450 12.12310 6.65470 772.00 312.00 0.00000 > > 1502.50 4.85150 12.18810 6.68090 775.00 312.00 0.00000 > > 1552.00 4.87850 12.25210 6.70660 777.00 312.00 0.00000 > > 1601.50 4.90520 12.31510 6.73170 779.00 312.00 0.00000 > > 1651.00 4.93190 12.37720 6.75640 781.00 312.00 0.00000 > > 1700.50 4.95840 12.43830 6.78070 784.00 312.00 0.00000 > > 1750.00 4.98470 12.49870 6.80460 786.00 312.00 0.00000 > > 1799.50 5.01090 12.55840 6.82820 788.00 312.00 0.00000 > > 1849.00 5.03700 12.61740 6.85140 790.00 312.00 0.00000 > > 1898.50 5.06290 12.67590 6.87450 792.00 312.00 0.00000 > > 1948.00 5.08870 12.73390 6.89720 793.00 312.00 0.00000 > > 1997.50 5.11430 12.79150 6.91990 795.00 312.00 0.00000 > > 2047.00 5.13980 12.84870 6.94230 797.00 312.00 0.00000 > > 2096.50 5.16520 12.90570 6.96470 799.00 312.00 0.00000 > > 2146.00 5.19040 12.96250 6.98700 801.00 312.00 0.00000 > > 2195.50 5.21540 13.01920 7.00930 803.00 312.00 0.00000 > > 2245.00 5.24030 13.07580 7.03160 805.00 312.00 0.00000 > > 2294.50 5.26510 13.13250 7.05400 807.00 312.00 0.00000 > > 2344.00 5.28980 13.18920 7.07650 809.00 312.00 0.00000 > > 2393.50 5.31420 13.24620 7.09910 811.00 312.00 0.00000 > > 2443.00 5.33860 13.30340 7.12180 813.00 312.00 0.00000 > > 2492.50 5.36280 13.36100 7.14490 815.00 312.00 0.00000 > > 2542.00 5.38690 13.41900 7.16810 817.00 312.00 0.00000 > > 2591.50 5.41080 13.47740 7.19170 819.00 312.00 0.00000 > > 2641.00 5.43450 13.53640 7.21560 820.00 312.00 0.00000 > > 2690.50 5.45820 13.59610 7.23980 822.00 312.00 0.00000 > > 2740.00 5.48170 13.65640 7.26450 823.00 312.00 0.00000 > > 2789.67 5.50510 13.66790 7.27680 826.00 312.00 0.00000 > > 2839.33 5.52840 13.67930 7.28920 826.00 312.00 0.00000 > > 2889.00 5.55150 13.69080 7.30150 826.00 312.00 0.00000 > > 2889.00 9.91450 8.00880 0.00000 57882.00 0.00 0.00000 > > 2939.33 9.99420 8.09630 0.00000 57822.00 0.00 0.00000 > > 2989.66 10.07220 8.18210 0.00000 57822.00 0.00 0.00000 > > 3039.99 10.14850 8.26620 0.00000 57822.00 0.00 0.00000 > > 3090.32 10.22330 8.34860 0.00000 57822.00 0.00 0.00000 > > 3140.66 10.29640 8.42930 0.00000 57822.00 0.00 0.00000 > > 3190.99 10.36790 8.50830 0.00000 57822.00 0.00 0.00000 > > 3241.32 10.43780 8.58560 0.00000 57822.00 0.00 0.00000 > > 3291.65 10.50620 8.66110 0.00000 57822.00 0.00 0.00000 > > 3341.98 10.57310 8.73500 0.00000 57822.00 0.00 0.00000 > > 3392.31 10.63850 8.80720 0.00000 57822.00 0.00 0.00000 > > 3442.64 10.70230 8.87760 0.00000 57822.00 0.00 0.00000 > > 3492.97 10.76470 8.94640 0.00000 57822.00 0.00 0.00000 > > 3543.30 10.82570 9.01340 0.00000 57822.00 0.00 0.00000 > > 3593.64 10.88520 9.07870 0.00000 57822.00 0.00 0.00000 > > 3643.97 10.94340 9.14240 0.00000 57822.00 0.00 0.00000 > > 3694.30 11.00010 9.20430 0.00000 57822.00 0.00 0.00000 > > 3744.63 11.05550 9.26450 0.00000 57822.00 0.00 0.00000 > > 3794.96 11.10950 9.32300 0.00000 57822.00 0.00 0.00000 > > 3845.29 11.16230 9.37980 0.00000 57822.00 0.00 0.00000 > > 3895.62 11.21370 9.43490 0.00000 57822.00 0.00 0.00000 > > 3945.95 11.26390 9.48830 0.00000 57822.00 0.00 0.00000 > > 3996.28 11.31270 9.54000 0.00000 57822.00 0.00 0.00000 > > 4046.62 11.36040 9.59000 0.00000 57822.00 0.00 0.00000 > > 4096.95 11.40690 9.63830 0.00000 57822.00 0.00 0.00000 > > 4147.28 11.45210 9.68480 0.00000 57822.00 0.00 0.00000 > > 4197.61 11.49620 9.72970 0.00000 57822.00 0.00 0.00000 > > 4247.94 11.53910 9.77280 0.00000 57822.00 0.00 0.00000 > > 4298.27 11.58090 9.81430 0.00000 57822.00 0.00 0.00000 > > 4348.60 11.62160 9.85400 0.00000 57822.00 0.00 0.00000 > > 4398.93 11.66120 9.89200 0.00000 57822.00 0.00 0.00000 > > 4449.26 11.69980 9.92840 0.00000 57822.00 0.00 0.00000 > > 4499.60 11.73730 9.96300 0.00000 57822.00 0.00 0.00000 > > 4549.93 11.77370 9.99590 0.00000 57822.00 0.00 0.00000 > > 4600.26 11.80920 10.02710 0.00000 57822.00 0.00 0.00000 > > 4650.59 11.84370 10.05660 0.00000 57822.00 0.00 0.00000 > > 4700.92 11.87720 10.08440 0.00000 57822.00 0.00 0.00000 > > 4751.25 11.90980 10.11050 0.00000 57822.00 0.00 0.00000 > > 4801.58 11.94140 10.13490 0.00000 57822.00 0.00 0.00000 > > 4851.91 11.97220 10.15760 0.00000 57822.00 0.00 0.00000 > > 4902.24 12.00210 10.17850 0.00000 57822.00 0.00 0.00000 > > 4952.58 12.03110 10.19780 0.00000 57822.00 0.00 0.00000 > > 5002.91 12.05930 10.21540 0.00000 57822.00 0.00 0.00000 > > 5053.24 12.08670 10.23120 0.00000 57822.00 0.00 0.00000 > > 5103.57 12.11330 10.24540 0.00000 57822.00 0.00 0.00000 > > 5153.90 12.13910 10.25780 0.00000 57882.00 0.00 0.00000 > > 5153.90 12.70370 11.09140 3.43850 445.00 85.00 0.00000 > > 5204.61 12.72890 11.10360 3.44880 444.00 85.00 0.00000 > > 5255.32 12.75300 11.11530 3.45870 443.00 85.00 0.00000 > > 5306.04 12.77600 11.12650 3.46810 441.00 85.00 0.00000 > > 5356.75 12.79800 11.13710 3.47700 440.00 85.00 0.00000 > > 5407.46 12.81880 11.14720 3.48560 439.00 85.00 0.00000 > > 5458.17 12.83870 11.15680 3.49370 438.00 85.00 0.00000 > > 5508.89 12.85740 11.16590 3.50130 437.00 85.00 0.00000 > > 5559.60 12.87510 11.17450 3.50850 436.00 85.00 0.00000 > > 5610.31 12.89170 11.18250 3.51530 436.00 85.00 0.00000 > > 5661.02 12.90720 11.19010 3.52170 435.00 85.00 0.00000 > > 5711.74 12.92170 11.19710 3.52760 434.00 85.00 0.00000 > > 5762.45 12.93510 11.20360 3.53300 434.00 85.00 0.00000 > > 5813.16 12.94740 11.20950 3.53810 433.00 85.00 0.00000 > > 5863.87 12.95860 11.21500 3.54270 433.00 85.00 0.00000 > > 5914.59 12.96880 11.21990 3.54680 432.00 85.00 0.00000 > > 5965.30 12.97790 11.22430 3.55050 432.00 85.00 0.00000 > > 6016.01 12.98590 11.22820 3.55380 432.00 85.00 0.00000 > > 6066.72 12.99290 11.23160 3.55670 432.00 85.00 0.00000 > > 6117.44 12.99880 11.23450 3.55910 431.00 85.00 0.00000 > > 6168.15 13.00360 11.23680 3.56100 431.00 85.00 0.00000 > > 6218.86 13.00740 11.23860 3.56260 431.00 85.00 0.00000 > > 6269.57 13.01000 11.23990 3.56370 431.00 85.00 0.00000 > > 6320.29 13.01170 11.24070 3.56430 0.00 0.00 0.00000 > > 6371.00 13.01220 11.24090 3.56450 0.00 0.00 0.00000 > > > >This is the PREM model: > > > > 0.00 2.60000 5.80000 3.20000 1456.00 600.00 0.00000 > > 15.00 2.90000 6.80000 3.90000 1350.00 600.00 0.00000 > > 24.40 2.90000 6.80000 3.90000 1350.00 600.00 0.00000 > > 24.40 3.38076 8.11061 4.49094 1446.00 600.00 0.00000 > > 40.00 3.37906 8.10119 4.48486 1446.00 600.00 0.00000 > > 60.00 3.37688 8.08907 4.47715 1447.00 600.00 0.00000 > > 80.00 3.37471 8.07689 4.46954 1447.00 600.00 0.00000 > > 80.00 3.37471 8.07688 4.46953 195.00 80.00 0.00000 > > 115.00 3.37091 8.05540 4.45643 195.00 80.00 0.00000 > > 150.00 3.36710 8.03370 4.44361 195.00 80.00 0.00000 > > 185.00 3.36330 8.01180 4.43108 195.00 80.00 0.00000 > > 220.00 3.35950 7.98970 4.41885 195.00 80.00 0.00000 > > 220.00 3.43578 8.55896 4.64391 362.00 143.00 0.00000 > > 265.00 3.46264 8.64552 4.67540 365.00 143.00 0.00000 > > 310.00 3.48951 8.73209 4.70690 367.00 143.00 0.00000 > > 355.00 3.51639 8.81867 4.73840 370.00 143.00 0.00000 > > 400.00 3.54325 8.90522 4.76989 372.00 143.00 0.00000 > > 400.00 3.72378 9.13397 4.93259 366.00 143.00 0.00000 > > 450.00 3.78678 9.38990 5.07842 365.00 143.00 0.00000 > > 500.00 3.84980 9.64588 5.22428 364.00 143.00 0.00000 > > 550.00 3.91282 9.90185 5.37014 363.00 143.00 0.00000 > > 600.00 3.97584 10.15782 5.51602 362.00 143.00 0.00000 > > 635.00 3.98399 10.21203 5.54311 362.00 143.00 0.00000 > > 670.00 3.99214 10.26662 5.57020 362.00 143.00 0.00000 > > 670.00 4.38071 10.75131 5.94508 759.00 312.00 0.00000 > > 721.00 4.41241 10.91005 6.09418 744.00 312.00 0.00000 > > 771.00 4.44317 11.06557 6.24046 730.00 312.00 0.00000 > > 871.00 4.50372 11.24490 6.31091 737.00 312.00 0.00000 > > 971.00 4.56307 11.41560 6.37813 743.00 312.00 0.00000 > > 1071.00 4.62129 11.57828 6.44232 750.00 312.00 0.00000 > > 1171.00 4.67844 11.73357 6.50370 755.00 312.00 0.00000 > > 1271.00 4.73460 11.88209 6.56250 761.00 312.00 0.00000 > > 1371.00 4.78983 12.02445 6.61891 766.00 312.00 0.00000 > > 1471.00 4.84422 12.16126 6.67317 770.00 312.00 0.00000 > > 1571.00 4.89783 12.29316 6.72548 775.00 312.00 0.00000 > > 1671.00 4.95073 12.42075 6.77606 779.00 312.00 0.00000 > > 1771.00 5.00299 12.54466 6.82512 784.00 312.00 0.00000 > > 1871.00 5.05469 12.66550 6.87289 788.00 312.00 0.00000 > > 1971.00 5.10590 12.78389 6.91957 792.00 312.00 0.00000 > > 2071.00 5.15669 12.90045 6.96538 795.00 312.00 0.00000 > > 2171.00 5.20713 13.01579 7.01053 799.00 312.00 0.00000 > > 2271.00 5.25729 13.13055 7.05525 803.00 312.00 0.00000 > > 2371.00 5.30724 13.24532 7.09974 807.00 312.00 0.00000 > > 2471.00 5.35706 13.36074 7.14423 811.00 312.00 0.00000 > > 2571.00 5.40681 13.47742 7.18892 815.00 312.00 0.00000 > > 2671.00 5.45657 13.59597 7.23403 819.00 312.00 0.00000 > > 2741.00 5.49145 13.68041 7.26597 822.00 312.00 0.00000 > > 2771.00 5.50642 13.68753 7.26575 823.00 312.00 0.00000 > > 2871.00 5.55641 13.71168 7.26486 826.00 312.00 0.00000 > > 2891.00 5.56645 13.71660 7.26466 826.00 312.00 0.00000 > > 2891.00 9.90349 8.06482 0.00000 57882.00 0.00 0.00000 > > 2971.00 10.02940 8.19939 0.00000 57822.00 0.00 0.00000 > > 3071.00 10.18134 8.36019 0.00000 57822.00 0.00 0.00000 > > 3171.00 10.32726 8.51298 0.00000 57822.00 0.00 0.00000 > > 3271.00 10.46727 8.65805 0.00000 57822.00 0.00 0.00000 > > 3371.00 10.60152 8.79573 0.00000 57822.00 0.00 0.00000 > > 3471.00 10.73012 8.92632 0.00000 57822.00 0.00 0.00000 > > 3571.00 10.85321 9.05015 0.00000 57822.00 0.00 0.00000 > > 3671.00 10.97091 9.16752 0.00000 57822.00 0.00 0.00000 > > 3771.00 11.08335 9.27876 0.00000 57822.00 0.00 0.00000 > > 3871.00 11.19067 9.38418 0.00000 57822.00 0.00 0.00000 > > 3971.00 11.29298 9.48409 0.00000 57822.00 0.00 0.00000 > > 4071.00 11.39042 9.57881 0.00000 57822.00 0.00 0.00000 > > 4171.00 11.48311 9.66865 0.00000 57822.00 0.00 0.00000 > > 4271.00 11.57119 9.75393 0.00000 57822.00 0.00 0.00000 > > 4371.00 11.65478 9.83496 0.00000 57822.00 0.00 0.00000 > > 4471.00 11.73401 9.91206 0.00000 57822.00 0.00 0.00000 > > 4571.00 11.80900 9.98554 0.00000 57822.00 0.00 0.00000 > > 4671.00 11.87990 10.05572 0.00000 57822.00 0.00 0.00000 > > 4771.00 11.94682 10.12291 0.00000 57822.00 0.00 0.00000 > > 4871.00 12.00989 10.18743 0.00000 57822.00 0.00 0.00000 > > 4971.00 12.06924 10.24959 0.00000 57822.00 0.00 0.00000 > > 5071.00 12.12500 10.30971 0.00000 57822.00 0.00 0.00000 > > 5149.50 12.16634 10.35568 0.00000 57822.00 0.00 0.00000 > > 5149.50 12.76360 11.02827 3.50432 445.00 85.00 0.00000 > > 5171.00 12.77493 11.03643 3.51002 445.00 85.00 0.00000 > > 5271.00 12.82501 11.07249 3.53522 443.00 85.00 0.00000 > > 5371.00 12.87073 11.10542 3.55823 440.00 85.00 0.00000 > > 5471.00 12.91211 11.13521 3.57905 439.00 85.00 0.00000 > > 5571.00 12.94912 11.16186 3.59767 437.00 85.00 0.00000 > > 5671.00 12.98178 11.18538 3.61411 436.00 85.00 0.00000 > > 5771.00 13.01009 11.20576 3.62835 434.00 85.00 0.00000 > > 5871.00 13.03404 11.22301 3.64041 433.00 85.00 0.00000 > > 5971.00 13.05364 11.23712 3.65027 432.00 85.00 0.00000 > > 6071.00 13.06888 11.24809 3.65794 432.00 85.00 0.00000 > > 6171.00 13.07977 11.25593 3.66342 431.00 85.00 0.00000 > > 6271.00 13.08630 11.26064 3.66670 431.00 85.00 0.00000 > > > > > > The next step to getting an accurate representation of what you see on your > >seismogram is a method called "synthetic seismograms" which uses a > >finite-element modelling technique to generate a seismogram based on the > >information you have given, like the earth model, source mechanism, and any > >departures from the model between the station and the quake. The earthquake > >source tells you how the elastic waves looked as they propagated out. There > >are characteristic radiation patterns for waves leaving an ideal fault (double > >couple) that are also used. > > > >****************************************************************************** > > > > John Hernlund > > E-mail: 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 > > _____________________________________________________________________ > > 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 From: Larry Cochrane Subject: Pile driving near me... Date: Fri, 12 Mar 1999 22:01:58 -0800 Hi Everyone, I'm recording some pile driving going on near me (about 2 blocks away) . I'm wondering if there is any useful information that can be gathered from my recordings? I have left some event files (my LC1, LC3, and LC3 files) on my system showing the end of a sequence of pile driving and then a M3.7 located in Mammoth Lakes, California. I would normally delete these files because the event was not recorded on my local sensors since the event was ~300km from me. The USGS sensors I am monitoring pickup the event, so it triggered my system just when the pile driving stopped. When you do an FFT of the pile driving data you get a peek frequency of ~ 5hz on both my Lehman and high freq. port of my SG sensor. The time between each stroke is around 1.4 seconds. I would think that I could use these "calibration" pulses to further calibrate my systems and maybe the local geology? (FYI: Edward Cranswick has answer my question about using the FBA-23 to calibrate my Lehman. I just need some time to write it all up...) Since the pile driving will stop in around 10 days, I want to gather as much info as possible before it ends. The amount of acceleration from each pulse is below the noise level of my strong motion sensor, so it can not be used. Next week I'll print out some "seismograms" of the pile driving and walk over and show the people doing the work. Maybe they will spend some time and explain how the driver works and maybe even run some experiments? -Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: hinges,flexures, contd Date: Sat, 13 Mar 1999 01:37:58 -0600 (CST) Following up on the mention of the "rolomite" bearing: any bearing that has any changing contact surface will not work in a seismometer. Even a highly polished surface with perfect cleanliness will have imperfections of the order of tens on microns (like a high quality optical surface with a scratch/dig quality of 20/5) that will relocate the axis of rotation of the bearing. There was a "flash in the pan" effort to use the "rolomite" idea when it surfaced in the '70s, but even the idea of "no" friction causes noise in the mass/boom movement of a seismometer where we are trying to detect nanometers of earth movement. I commented on this last Sept 11 in a discussion on some historical info: A variation that is closer to the "rolomite" design is seen on the large Johnson-Matheson 0.8 second vertical of 1960, where a "cardan" hinge is used on both ends of the spring cantilevers. This uses a single bronze strip with the wider center strap folded back thru the narrower outer straps and clamped only on one side. From the end it forms a figure-8 pattern around the fixed and the moving dowel pins. Flexure occurs across the centers of the crossed straps. However, unlike the "rolomite", there is no physical contact between the two supporting shafts; as this would add significant micro-positioning and thermal noise. The "cardan" hinge will only work when under constant tension, which is the case with this seis with a 20kg mass and a cantilever ratio of about 10 to 1. (This seis had a fatal design flaw in that the coil was fixed to the base and the magnet was the moving mass; it was very susceptible to geomagnetic storms in spite of a very heavy 1/8" steel case). For the past decade the crossed flexures have been assembled inside a pair of small axially aligned rings that are easily installed on the seismometer. They are very low noise because the contact locations of the flexing members are very well constrained. These "bendix" hinges are widely used in the current broadband designs. They can be very compact (less than 1/8" diameter) and are made from pretty exotic metals. An individual flexure may cost more than $100 though. And they are relatively fragile; the Streckeicen VBB seises cannot be tipped sideways with the clamps removed without damaging the hinges. 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 From: "W. S. Titus" Subject: Re: Pile driving near me... Date: Fri, 12 Mar 1999 23:49:22 -0800 Larry, In my undergarduate days (I'm a geologist/seismologist of sorts), I did some grunt work with a USGS geophysist from Seattle who was using precisely that type of data to measure the depth to bedrock in thick, sediment-filled basins. His technique involved getting a bunch of strapping young grad students to run "jumping jack" vibrating compactors around while he recorded seismograms from a small, portable recorder. He used a stacking routine of some sort to extract the information from the data, perhaps in the manner of a refraction survey. As I recall, his name was Don King, and he was a very friendly fellow who dearly loved to discuss his work. Don may still be with the USGS, in which case you or ED Cranswick may be able to track him down and get the "real" story. By the way, take the time to talk to the pile-driving crew. There is undoubtably a geologist or geotechnical engineer working with them at the site who would be fascinated by your data. He may, in fact, be making some recordings of his own, that is often done to monitor potentially damaging vibrations. Been there, done that. Bill Titus titus@............ Larry Cochrane wrote: > I'm recording some pile driving going on near me ... > > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: Re: hinges,flexures, contd Date: Sat, 13 Mar 1999 07:55:34 -0500 Sean-Thomas, Thanks for the inside info. It's good to be able to temper theory with some real practical knowledge. Though the Rolamite is clearly not going to be a good answer, I'm still attracted to the "tension" version of that hinge. It looks pretty good if it is stiff enough against rotation about a vertical axis. Am a little concerned with N-S / Z axis coupling. Here is a URL for a company that makes pivots that look a lot like what you were describing. They give quite thorough specs. Wonder if that's what Streckeisen uses? http://www.lucasutica.com/pivots/ Regards, Brett At 01:37 AM 3/13/99 -0600, you wrote: > Following up on the mention of the "rolomite" bearing: >any bearing that has any changing contact surface will not work > >For the past decade the crossed flexures have been assembled inside >a pair of small axially aligned rings that are easily installed on >the seismometer. They are very low noise because the contact locations >of the flexing members are very well constrained. >These "bendix" hinges are widely used in the current broadband designs. >They can be very compact (less than 1/8" diameter) and are made from pretty >exotic metals. An individual flexure may cost more than $100 though. >And they are relatively fragile; the Streckeicen VBB seises cannot >be tipped sideways with the clamps removed without damaging the hinges. > >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) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brian Chesire Subject: Re: hinges,flexures, contd Date: Sat, 13 Mar 1999 08:04:22 -0700 Bett, Lucas bought the Bendix "Free Flex" hinge operation several years ago, along with a whole host of other companies, such as Schaevitz (they make LVDT's) etc. Same parts, new owner. We use the pivots in some of our center of mass scales. They aren't cheap. Brian WA5PPO Tucson, AZ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Doug Crice Subject: Re: Pile driving near me... Date: Sat, 13 Mar 1999 07:56:21 -0800 Determining your local geology from pile driving. The simplest approach (theoretically) is to measure the interval between the pile impact and the seismic arrival at a series of points between the pile driver and your seismograph. Logistically, it's a little inconvenient because you would have to move your seismometer a number of times (say to points every 10 meters between the machine and your house) and also time the impact precisely to find the interval time. The calculations aren't too complicated, but too much for this space. The waves refract through the ground, going deeper as the distance increases and it becomes quicker to go down to the higher velocity rock. Logistically more convenient and mathmatically elegant is to locate a vertical seismometer a little ways toward the pile and another one a little further away. Record both at the same time, them do a cross-spectral analysis of velocity verses frequency. The short wavelength surface waves travel at shallower depths than the long wavelengths, and the velocities are depending on the shear strength of the material. From the shear wave velocities, you can deduce the shear strength and thus the material types and foundation characteristics. The whole process is called "Spectral Analysis of Surface Waves" or more commonly SASW, and it is being adapted to exploration geophysics. One of the beauties is that shear wave velocities are much more diagnostic of material types than P wave velocities. Do an internet search for SASW and you should find some papers. Interestingly enough, the method was developed by earthquake folks and is being adapted by engineers, even down to testing concrete pavement. -- Doug Crice web site http://www.georadar.com GeoRadar Inc. e-mail dcrice@............ 19623 Via Escuela Drive phone 408-867-3792 Saratoga, CA 95070 USA fax 408-867-4900 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: Pile driving near me... Date: Sat, 13 Mar 1999 09:33:18 -0800 Hi Larry The energy of the pile driving can be determined but one needs to know the hammer being used. We measure the bearing values of the piles using the blows/ft with the manufactures rating for the hammer. Maybe the energy could be usefull as a calibration check? Barry Larry Cochrane wrote: > Hi Everyone, > > I'm recording some pile driving going on near me (about 2 blocks away) . > I'm wondering if there is any useful information that can be gathered from > my recordings? I have left some event files (my LC1, LC3, and LC3 files) > on my system showing the end of a sequence of pile driving and then a M3.7 > located in Mammoth Lakes, California. I would normally delete these files > because the event was not recorded on my local sensors since the event was > ~300km from me. The USGS sensors I am monitoring pickup the event, so it > triggered my system just when the pile driving stopped. > snip _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Doug Crice Subject: Re: Pile driving near me... Date: Sat, 13 Mar 1999 10:06:04 -0800 barry lotz wrote: > > Hi Larry > The energy of the pile driving can be determined but one needs to know the > hammer being used. We measure the bearing values of the piles using the > blows/ft with the manufactures rating for the hammer. Maybe the energy could be > usefull as a calibration check? > Barry In exploration geophysics, it's relatively difficult to relate particle velocity to energy when a by-product is plastic deformation. For example, there's a seismic source called "Betsy" which fires an 8-gague 3-oz zinc slug into the ground which advertises an impact energy of 9000 ft-lbs based on the muzzle velocity and slug mass. However, this same source is only marginally better than hitting a steel plate with a 12-lb sledgehammer, except when the ground is saturated. It seems that all that energy is consumed in "blowing a hole in the ground" and very little goes into elastic waves. A similar source, using a standard shotgun shell in the end of a pipe detonated under the ground surface is much more effective, and just about as effective without the pellets--the elastic waves come from expanding combustion gases in the ground (about 1/2 meter down). -- Doug Crice web site http://www.georadar.com GeoRadar Inc. e-mail dcrice@............ 19623 Via Escuela Drive phone 408-867-3792 Saratoga, CA 95070 USA fax 408-867-4900 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: Reading Seismograms Date: Sat, 13 Mar 1999 11:23:48 -0700 (MST) On Fri, 12 Mar 1999, barry lotz wrote: > $0.02 I think the major phases have different frequenct components. > ie I have run a simple program which does an FFT on a moving time window and > you can see the P then S then Surface waves arrive. -- Just a little more to > aid the eye. > Regards > Barry Barry just reminded me of another way to get a general idea of the distance. The way Q is defined for seismic waves, the higher frequency components decay much faster per unit distance than the lower frequency components. The basic expression for amplitude as a function of distance is: A = Ao*exp(-2*pi*f*r/Q), where f is the frequency, r is the distance and Q is the attentuation factor. Because of this, if you plot all of the amplitudes versus their frequency via a FFT with the Amplitude scale being logarithmic then you will get something like a negatively sloping straight line. Measurements of this slope and ways of dealing with its irregularities are all part of the problem of measuring Q, which can be found directly from the equation of that straight line. However, as you can tell from the above equation, if you assume certain values for Q (given by the earth models) then you can use this slope to determine r, the distance. In reality, because the instrument's response to different frequencies will also affect the FFT expect for a broadband instrument in its flat response range, and noise of course, this becomes very difficult, and large errors in the determination of distance will arise. But from this discussion you can get a general idea about the appearance of the FFT: For greater distances the slope of the straight line feature in the frequency range of your recording device will be steeper than for closer events. This slope is another characteristic of a seismic recording that can be taken into account for determining the distance to the quake. Also, regarding Barry's suggestions, you can see from the earth models that the Q value is different for P and for S waves. Hence their appearance in an FFT will differ in behavior as described above. ****************************************************************************** John Hernlund E-mail: 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 From: S-T Morrissey Subject: magnet/coil mounting Date: Sat, 13 Mar 1999 13:03:10 -0600 (CST) Dick, Regarding your question about mounting the magnet on the boom as the seismometer mass: here is a note from last June: Basically it makes the seis a magnetometer of sorts that interacts with all ferrous materials, moving or fixed, as well as geomagnetic storms. Some amateur designs have tried the idea, but they have been known to shift in output from other temporary ferro-magnetic disturbances like a large hunting knife, steel-shank boots, and analog multimeters. One design could be "calibrated" by rotating a small bar magnet on a table several feed away. Some designs have attempted to use heavy steel casing or shielding by mu-metal enclosures. (This IS necessry for high gain vertical sensors, since most spring material is ferromagnetic). Seismic instrument designers long ago found this out, and mounted the magnets to the frame, and the coils to the boom or moving mass (which can be the coils themselves), even though this requires the extra effort of making fine coiled wire jumpers across the hinge or pivot to convey the signals. (In geophones, the suspension diaphram springs are sometimes used to conduct the signal from the moving coil, as in the L4-C). The fine (#44) wires do not add "much" noise if they are loose and do not touch each other. Even the $$$$ STS-1 seises use them. I have 5 pairs at the hinge of the STM-8: one for the force coil, three for calibration coils, and one pair for the zero centering motor, which is mounted on the moving flange of the hinge. Another advantage of mounting the magnets to the frame is that you can use large magnets of wierd geometry, even the 350lb neodymium magnet Meredith suggested for his "April 1" design. Look at the drawing I just posted of the S5000H. It clearly shows the large right side magnet mounted to the cast aluminum base, and the hollow coil mounted to the side of the mass. It also shows the wiring and terminal strips for the jumpers across the lower pivot. When I get a chance, I might try to get a photo of the seis I am still operating. 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 From: barry lotz Subject: Re: Reading Seismograms Date: Sat, 13 Mar 1999 12:24:45 -0800 John I like your equation. It seems possible for one to take their previously recorded events and perform FFTs on the P,S and Surface waves. Winquake allows this. Then somehow incorporate the results into a distance function. The problem I see with my sensors is that the different phases respond differently depending on the epicenter's geographic location. Larry- does you FFT routine allow for a summation of the responses at the various frequencies? Regards Barry John Hernlund wrote: > Barry just reminded me of another way to get a general idea of the > distance. The way Q is defined for seismic waves, the higher frequency > components decay much faster per unit distance than the lower frequency > components. The basic expression for amplitude as a function of distance is: > A = Ao*exp(-2*pi*f*r/Q), where f is the frequency, r is the distance and Q is > the attentuation factor. Because of this, if you plot all of the amplitudes > versus their frequency via a FFT with the Amplitude scale being logarithmic > then you will get something like a negatively sloping straight line. > Measurements of this slope and ways of dealing with its irregularities are all > part of the problem of measuring Q, which can be found directly from the > equation of that straight line. However, as you can tell from the above > equation, if you assume certain values for Q (given by the earth models) then > you can use this slope to determine r, the distance. In reality, because the > instrument's response to different frequencies will also affect the FFT expect > for a broadband instrument in its flat response range, and noise of course, > this becomes very difficult, and large errors in the determination of > distance will arise. But from this discussion you can get a general idea > about the appearance of the FFT: > > For greater distances the slope of the straight line feature in the frequency > range of your recording device will be steeper than for closer events. This > slope is another characteristic of a seismic recording that can be taken into > account for determining the distance to the quake. > > Also, regarding Barry's suggestions, you can see from the earth models that > the Q value is different for P and for S waves. Hence their appearance in an > FFT will differ in behavior as described above. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Capacitors Date: Sat, 13 Mar 1999 12:34:11 -0800 Back to an old topic for a second. I was trying to find a reasonable quality polarized cap for large Ufarad values like 60-100. I figured on using back to back polarized caps, but in looking at Digikey's catalog there were a multitude of caps available. Tantalums were my first thought but for 150uf caps the price was fairly high . Is there an acceptable type of electrolytic? There are several types listed. I guess I could use $ for a selection. Figuring that you get what you pay for . I would prefer a more scientific selection proceedure. Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Re: Pile driving near me... Date: Sat, 13 Mar 1999 14:35:39 -0700 Bill- I think the person you are referring to is Ken King; he was my supervisor for a few years here in Golden when I first transferred from USGS Menlo Park in 1986. However, I never went out in the field with him when he used the "wackers" (vibrating compactors), and he retired in 1993. He and his crew -- Dave Carver, Rob Williams, Dave Worley (who are all still here at USGS Golden) -- did alot of the early work on site response in Seattle, and we are continuing that work now in a project headed by Art Frankel (an informal website about some of that work can be seen at ) -Edward "W. S. Titus" wrote: > Larry, > > In my undergarduate days (I'm a geologist/seismologist of sorts), I did some > grunt work with a USGS geophysist from Seattle who was using precisely that > type of data to measure the depth to bedrock in thick, sediment-filled basins. > His technique involved getting a bunch of strapping young grad students to run > "jumping jack" vibrating compactors around while he recorded seismograms from a > small, portable recorder. > He used a stacking routine of some sort to extract the information from the > data, perhaps in the manner of a refraction survey. As I recall, his name was > Don King, and he was a very friendly fellow who dearly loved to discuss his > work. Don may still be with the USGS, in which case you or ED Cranswick may be > able to track him down and get the "real" story. > > By the way, take the time to talk to the pile-driving crew. There is > undoubtably a geologist or geotechnical engineer working with them at the site > who would be fascinated by your data. He may, in fact, be making some > recordings of his own, that is often done to monitor potentially damaging > vibrations. Been there, done that. > > Bill Titus > titus@............ > > Larry Cochrane wrote: > > > I'm recording some pile driving going on near me ... > > > > > > > > _____________________________________________________________________ > > 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 From: S-T Morrissey Subject: Re: Capacitors Date: Sat, 13 Mar 1999 18:09:10 -0600 (CST) Barry, Tantalum capacitors' values change tremendously with temperature. Except for power supplies or space limitations, I generally use aluminum electrolytics for greater than 1uf values. When I order capacitors where the value is important (as compared to a power supply, where + 50% doesn't matter), I look for the widest temperature range that is still within 10%. ANd then I price shop. I just ordered several 100 from Newark, which had the best prices (you can order from their web site). I usually find Digi-key a bit more expensive, as is Tech-America; but Mouser often has good prices and unusual component values. I just ordered some 10uf polypropylyne caps for the VBB seis feedback elements, and paid $3 ea. from Mouser; they were $10 and up from others. Polypropylene (or polystyrenes, which are more temperature sensitive) are non-polarized and are the preferred type for long period time/frequency dependant applications, such as filters, feedback and integrator timing. With 40 of them at 10% tolerance, I could measure each (they ranged from 9.55 to 10.45) and parallel them to exactly the 20 to 80 uf values I need. But for high-value needs like a high-pass coupling (like 1000uf), the Al electrolytics used back-to-back are good if they are 10% tolerance so that the response of the high-pass filter will not change with time. Speaking of Mouser, I just bought some surprisingly good DC-DC converters for $19. THey accept 9 to 18 volts input (from an $11 12V, 500 ma AC adapter from Radio Shack or others), and produce + and - 15 volts at 100 ma regulated at 1%. SO $30 gets you a decent instrumentation power supply. ( For the VBB I further regulate it to +,- 12V at 0.02% with LM317M and LM337M ICs). The Mouser number is 618-OBQ23WC1224 on page 252. 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 From: Larry Cochrane Subject: Re: Reading Seismograms Date: Sun, 14 Mar 1999 13:08:53 -0800 At 12:24 PM 3/13/99 -0800, you wrote: >John > I like your equation. It seems possible for one to take their previously >recorded events and perform FFTs on the P,S and Surface waves. Winquake allows >this. Then somehow incorporate the results into a distance function. The problem I >see with my sensors is that the different phases respond differently depending on >the epicenter's geographic location. >Larry- does you FFT routine allow for a summation of the responses at the various >frequencies? Not at this time.... -Larry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Re: Pile driving near me... Date: Sun, 14 Mar 1999 15:10:53 -0800 Doug, Thanks for the info. One thing I want to look into is what is causing the 5.2 hz peek in the FFT. I'm thinking maybe the concrete slab and / or the house sitting on it has a resonance at that freq. I should be able to check this out if I can get a hold of a small senor that I can move around. Its just not practical to move my Lehman or SG sensors around do to their size. I would think a single component short period vertical would do? Or would I get some useful info if I can record a 3 component senor? I might be able to borrow a sensors from the local USGS. I already have the FBA-23 on loan from them... One problem maybe the sample rate limitation on SDR. Since it can only sample at a max rate of 100 SPS, I maybe loosing some interesting information... I have another data logging system that I can use. I'm doing some work for Willie Lee ( USGS seismologist, now retired) and the IASPEI (Internation Association of Seismology and Physics of the Earths Interior) organization. I have an A/D card from them that can record up to 64 channels at 200SPS or less channels at a higher sample rate. If I set the sample rate high enough, I should be able to eliminate any need for a low-pass filter between the sensor and A/D board. The problem with this system is it produces event files in the PC-SUDS format. A format currently not supported by WinQuake. I would have to learn how to use their tools, or come up with a conversion program that would convert the data to the PSN format. -Larry Cochrane Redwood City, PSN At 07:56 AM 3/13/99 -0800, you wrote: >Determining your local geology from pile driving. > >The simplest approach (theoretically) is to measure the interval between >the pile impact and the seismic arrival at a series of points between >the pile driver and your seismograph. Logistically, it's a little >inconvenient because you would have to move your seismometer a number of >times (say to points every 10 meters between the machine and your house) >and also time the impact precisely to find the interval time. The >calculations aren't too complicated, but too much for this space. The >waves refract through the ground, going deeper as the distance increases >and it becomes quicker to go down to the higher velocity rock. > >Logistically more convenient and mathmatically elegant is to locate a >vertical seismometer a little ways toward the pile and another one a >little further away. Record both at the same time, them do a >cross-spectral analysis of velocity verses frequency. The short >wavelength surface waves travel at shallower depths than the long >wavelengths, and the velocities are depending on the shear strength of >the material. From the shear wave velocities, you can deduce the shear >strength and thus the material types and foundation characteristics. > >The whole process is called "Spectral Analysis of Surface Waves" or more >commonly SASW, and it is being adapted to exploration geophysics. One >of the beauties is that shear wave velocities are much more diagnostic >of material types than P wave velocities. Do an internet search for >SASW and you should find some papers. Interestingly enough, the method >was developed by earthquake folks and is being adapted by engineers, >even down to testing concrete pavement. >-- >Doug Crice web site http://www.georadar.com >GeoRadar Inc. e-mail dcrice@............ >19623 Via Escuela Drive phone 408-867-3792 >Saratoga, CA 95070 USA fax 408-867-4900 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Re: Pile driving near me... Date: Sun, 14 Mar 1999 16:33:00 -0700 Doug- We (USGS Golden) have been interested in using the SASW technique to characterize site response, but we have never gotten our act together to the point of critical mass to actually do some tests of it. For the last decade, we have been relying upon shallow reflection/refraction surveys to get information about the near-surface velocity structure and one of these days we will do the surface wave thing. I agree with you that the best thing Larry could do would be to record the signal near the pile-driving source and simultaneously record it with another sensor that could be moved in steps from the source towards his home station. However, in the absence of a portable recorder, he could simply record the blows on his home system and try to stack them just as a signal/noise reduction experiment. -Edward Doug Crice wrote: > Determining your local geology from pile driving. > > The simplest approach (theoretically) is to measure the interval between > the pile impact and the seismic arrival at a series of points between > the pile driver and your seismograph. Logistically, it's a little > inconvenient because you would have to move your seismometer a number of > times (say to points every 10 meters between the machine and your house) > and also time the impact precisely to find the interval time. The > calculations aren't too complicated, but too much for this space. The > waves refract through the ground, going deeper as the distance increases > and it becomes quicker to go down to the higher velocity rock. > > Logistically more convenient and mathmatically elegant is to locate a > vertical seismometer a little ways toward the pile and another one a > little further away. Record both at the same time, them do a > cross-spectral analysis of velocity verses frequency. The short > wavelength surface waves travel at shallower depths than the long > wavelengths, and the velocities are depending on the shear strength of > the material. From the shear wave velocities, you can deduce the shear > strength and thus the material types and foundation characteristics. > > The whole process is called "Spectral Analysis of Surface Waves" or more > commonly SASW, and it is being adapted to exploration geophysics. One > of the beauties is that shear wave velocities are much more diagnostic > of material types than P wave velocities. Do an internet search for > SASW and you should find some papers. Interestingly enough, the method > was developed by earthquake folks and is being adapted by engineers, > even down to testing concrete pavement. > -- > Doug Crice web site http://www.georadar.com > GeoRadar Inc. e-mail dcrice@............ > 19623 Via Escuela Drive phone 408-867-3792 > Saratoga, CA 95070 USA fax 408-867-4900 > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Taber Subject: Re: Reading Seismograms Date: Mon, 15 Mar 1999 15:01:06 +1300 (NZDT) Dick You wrote: >Thanks for the information about earth models. My question is a tad more >basic. When confronted with a seismogram what is the best way to approach >making picks IF YOU DON'T KNOW THE HYPOCENTER. Are there characteristic >shapes and relationships that would let one determine a P from a Pp and >even something so simple as an S wave. After all they must have used the >eyeball approach before the days of the internet or telemetry. Here is how students were taught when I was at Lamont. I expect it is similar to the way picks were done before computers or telemetry. It requires a set of standardized travel time plots. 1.Take the helicorder record from one of the components and lay it on the table. Take a piece of paper tape (like what was used in computer punch tape, for those who can remember that far back) and line it up along the seismogram. 2.Mark the first arrival on the tape and then begin making marks on the tape at each point on the seismogram that appears to correspond to a new phase. 3. From the relative size of the surface waves (the usually large, late arriving waves) compared to the earlier arrivals make a crude guess as to depth, ie 33, 100, 300, 600 km. The smaller the surface waves the deeper the guess. 4. Select the travel time plot that corresponds to that depth. The travel time plots were printed at the same time scale as the helicorder, and had time vs distance curves for each of the major phases. 5. Slide your paper tape along the distance axis until you get the best match between your picks and the phases on the plot. If there was not a good match then try a travel time plot with a different depth. Compare with phases selected on the other components. This is the main iterative step where one learns to identfy different phases. This gives you an estimate of distance and depth. You can then get an estimate of azimuth by looking at the polarity of the first arrival on all 3 components. For example, f you get positive up, N, and E, then the earthquake came from azimuth between 180 and 270 degrees. You then go to a globe and using a knowledge of the global distribution of earthquakes, estimate the likely source of the earthquake. With some practice you can usually come close to the actual location John Taber _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: VRDT transducer info Date: Sun, 14 Mar 1999 21:05:36 -0600 (CST) Barry, The 2mm gap in the VRDT is a tradeoff between sensitivity (smaller gap) and practicality. 2 mm makes the transducer easy to work with and still have reasonable sensitivity (100mv/micron). Since the sensor is only sensitive to the axial position of the ferrous vane, horizontal mis-alignment and even tilting of the vane in the gap is not a problem. This is an advantage for a large seismometer, where lateral movement of the boom has to be tolerated. When I install the sensor in a VBB seismometer, I simply align it visually and then fine-tune it using its output. When the feedback is turned on, the vane will stay centered within the capability of the feedback, which has a gain of 25 to 100 (for the STM-8). A gain of 100 means that a boom movement of 1 mm without feedback is constrained to 10 microns with the feedback on. Considering the dynamic range, this means that if the voltage limit is 10 volts, the transducer limits at 100 microns without the feedback, but at an equilavent ground displacement of 10 000 microns, or 10 mm, with the feedback on. If the transducer noise level is 1 mv or 10 nanometers, the dynamic range is 1 million, or 120 db. You asked about the commercial oscillator/amplifier/demodulator unit that I have used: it is the module used in the Validyne pressure gauges, where the VRDT consists of two coils embedded in the pressure sensor housing that sense the movement of the diaphram between them. I have used them mostly in conjunction with a Schaevitz LVDT (the 005MHR) for the high resolution microbarometer with an output of 100mv/millibar (or 10mv/micron from the LVDT). The Validyne osc/amp/demodulator is very low power, like 12 volts at 10 ma, and uses a 5hkz oscillator; the oscillator waveform is a mess, so cable capacitances/movement can be a problem. The unit uses a 7660 DC-DC inverter and they use regulated supplies for the the CD4047 oscillator. It uses synchronous demodulation with a 4066. I last bought the modules over ten years ago and paid about $100. It is from their P300 series of sensors, and is part number 9539. It consists of a 1.5" cube made of 4 stacked PC boards; be sure to order it unpotted; this lets it be opened out to a 3" x 1.5" x .6" unit that fits in Bud CU123 boxes. For the seismometer, the Validyne module will work, but it is about 10 times noisier than the osc/amp/demod design that I am using that was developed for the tiltmeters. The output with the VRDT is about 40 mv/micron. I would guess that when the new electronics is commercially available, the cost will be significantly less. 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 From: Larry Cochrane Subject: Re: Calibrating my Lehman using integration - the answer Date: Sun, 14 Mar 1999 20:29:49 -0800 Hi Everyone, Edward Cranswick has taken a look at my event files and has answered my question about how to calibrate my Lehman using the FBA-23 accelerometer. Using a program(s?) he wrote may years ago to analyze earthquakes, and the sensors used to record them, he came up with the following numbers. The event produced a peek acceleration of 2.634 cm / sec * sec or 2.685 mg (1g = 980.665 cm / sec * sec). Edward then integrated the acceleration event file and his program calculated a peek velocity of .07191 cm / sec. So the event produced a peek velocity of .07191 cm / sec. When I integrate the event file using WinQuake I get a peek "count" of ~1.3. Edward's program calculates the actual velocity based on the peek number. Unfortunately, Edward's program does not display the peek "count" number so he calculated it for me. The number he came up with is ~1.2. Edward's program calculates the velocity from the peek number using the formula: peek number / counts per volt / system gain / sensitivity of the FBA channel. Placing some numbers to the formula you get: 1.2 / 6553 / .5 / ..00509 = .0719 The numbers are: 1.2 = peek number obtained after integration. 6553 is the counts per volt of the A/D system. This comes from taking 32768 counts / 5 volts. ..5 is the gain between the sensor and the A/D converter. In this case there is a divide by 2 between the sensor and the A/D converter. ..00509 is the sensitivity of the FBA in volts / cm / sec * sec. The sensor I have outputs 5 volts at 1 g or 980.66 cm / sec * sec. So 5 / 980.66 = ..00509. I also found that if you take the sensitivity in cm / sec * sec per bit and multiply it by the 1.2 peek # you get the same thing. Since 2 g = 1961.33 (980.665 * 2) and my A/D converter has +- 32786 counts you get .05985 (1961.33 / 32768). 1.2 * .05985 = ~.0718. Ok... so now we know that I got a peek velocity of .0719 for the event. My Lehman, a velocity device, recorded a peek A/D count of 32100. So each count = 2.24 e-6 cm / sec (.0719 / 32100). A more common way of expressing the sensitivity of a velocity sensor is in volts / cm / sec. I got a peek count of 32100 counts, this = 4.898 of output voltage from the sensor (including the amplifier / filter board) . If you take 4.898 / .0791 you get 68.1 volts / cm / sec. So the sensitivity of my Lehman is 68.1 v / cm / sec., if the boom hasn't wandered off too much for the center position I try too keep it at. I measured the gain of the amp / filter card between the pickup coil and the A/D converter the other day. The gain is ~1066, so the sensitivity of the coil and magnet I am using is ~ .06388 (68.1 / 1066) volts / cm / sec. I would like to thank Edward for all of the work he did doing the actual data manipulation and then taking the time to explain it all to me. Regards, Larry Cochrane Redwood City, PSN My original post... ---------------------------------------------------------------------------- --------------------------------------- Hi Everyone, I have some questions for the experts on how to calibrate my Lehman using the FBA-23 accelerometer I am monitoring. First some background; On 2/04/99 at 0:19:36 UTC we had an interesting local double event. The first event was ~ML 3.8 and the second event was somewhat smaller. The events where about 72km from my house. I recorded both events on scale with my Lehman, peek count = 32100 out of 32768, and the FBA-23 recorded a peek count of 43. The files I am using for the information below can be downloaded from my system. The event files are 990204a.lc1, my N-S Lehman, and 990204a.lc5 the N-S channel of the FBA-23. The two sensors are located right next to each other in a spare bedroom. Since I know the characteristics (sensitivity) of FBA sensor, in fact it just got calibration at Kinemetrics a few days before the event!, I should be able to use it to calibrate my Lehman. The problem is the FBA outputs acceleration and my Lehman outputs velocity. Using WinQuake's integration feature, I should be able to convert the FBA data to velocity, by integrating once, and use this to come up with the sensitivity of my Lehman. The FBA channel has the following sensitivity; Full scale is +- 2g, this gives a min/max A/D count of 32768 (16 bit A/D system) so each A/D count is 61.03 ug ( 65536 counts / 4 g). The event produced a peek count of 43, so the peek acceleration was around 2.62 mg (61.03 ug * 43). After integrating the FBA event file, I get a peek count of 1.39 (Note: you will need to use the newest WinQuake beta release to see numbers below 1 after integration). After doing the integration, the event file looks very similar to my Lehman around the S wave, except for the 32100 to 1.39 count difference. Since there is a 32100 to 1.39 difference, I think I can say that my Lehman is ~23,093 times more sensitive then the FBA sensor, after converting to velocity. That would make sense, since the FBA is a strong motion sensor and my Lehman is a higher gain device. So my question basically gets down to what is the 1.39 number I get after doing the integration and can I say that my Lehman has a gain of 23K that number, more or less? Since the FBA senors is a little out of the background noise of the my system (about +- 5 counts or +- .3 mg) there is some error in the 2.62 mg and 1.39 numbers. Part of the 23k gain difference is the amplification between the pickup coil on the Lehman and the A/D converter. I think the gain of my amp / filter card is set too ~5K. If the gain is 5K, then the coil / magnet combination is only around 4.6 times more sensitive then the FBA, after integrating etc.... What I would like to do is measure the actual sensitivity of the coil and magnet, some how, and compare it to the calculated number using the FBA / WinQuake integration method. I think it would be interesting too try and "close the loop" and calibrate my Lehman using the two methods and see how close I can get. One more thing, it has to do with the damping of my Lehman. I think it is safe to say that the actual amount of damping of my Lehman has little effect on my results. My Lehman currently has a natural period of around 8 seconds (If I set it any longer I constantly have to adjust the #$%&^ thing). As I understand it, damping effects the response around the natural period of the pendulum, more of less.... Since the period of the wave used for the peek measurements information above are around 3 to 5 hz, well above the 8 sec period of my Lehman, a little under or over damped system should not effect things too much. Is this a correct statement? Thanks for any input... Regards, Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Re: Pile driving near me... Date: Sun, 14 Mar 1999 22:11:50 -0700 Larry- You are right! You did mention the Willie Lee machine. I'll send those vertical jugs to you tomorrow. -Edward PS. Thank you for your kind comments about our work to calibrate your Lehman. Larry Cochrane wrote: > Doug, > > Thanks for the info. One thing I want to look into is what is causing the > 5.2 hz peek > in the FFT. I'm thinking maybe the concrete slab and / or the house sitting > on it has a resonance > at that freq. I should be able to check this out if I can get a hold of a > small senor that I can move around. Its just not practical to move my > Lehman or SG sensors around do to their size. I would think a single > component short period vertical would do? Or would I get some useful info > if I can record a 3 component senor? I might be able to borrow a sensors > from the local USGS. I already have the FBA-23 on loan from them... > > One problem maybe the sample rate limitation on SDR. Since it can only > sample at a max rate of 100 SPS, I maybe loosing some interesting > information... I have another data logging system that I can use. I'm doing > some work for Willie Lee ( USGS seismologist, now retired) and the IASPEI > (Internation Association of Seismology and Physics of the Earths Interior) > organization. I have an A/D card from them that can record up to 64 > channels at 200SPS or less channels at a higher sample rate. If I set the > sample rate high enough, I should be able to eliminate any need for a > low-pass filter between the sensor and A/D board. The problem with this > system is it produces event files in the PC-SUDS format. A format currently > not supported by WinQuake. I would have to learn how to use their tools, or > come up with a conversion program that would convert the data to the PSN > format. > > -Larry Cochrane > Redwood City, PSN > > At 07:56 AM 3/13/99 -0800, you wrote: > >Determining your local geology from pile driving. > > > >The simplest approach (theoretically) is to measure the interval between > >the pile impact and the seismic arrival at a series of points between > >the pile driver and your seismograph. Logistically, it's a little > >inconvenient because you would have to move your seismometer a number of > >times (say to points every 10 meters between the machine and your house) > >and also time the impact precisely to find the interval time. The > >calculations aren't too complicated, but too much for this space. The > >waves refract through the ground, going deeper as the distance increases > >and it becomes quicker to go down to the higher velocity rock. > > > >Logistically more convenient and mathmatically elegant is to locate a > >vertical seismometer a little ways toward the pile and another one a > >little further away. Record both at the same time, them do a > >cross-spectral analysis of velocity verses frequency. The short > >wavelength surface waves travel at shallower depths than the long > >wavelengths, and the velocities are depending on the shear strength of > >the material. From the shear wave velocities, you can deduce the shear > >strength and thus the material types and foundation characteristics. > > > >The whole process is called "Spectral Analysis of Surface Waves" or more > >commonly SASW, and it is being adapted to exploration geophysics. One > >of the beauties is that shear wave velocities are much more diagnostic > >of material types than P wave velocities. Do an internet search for > >SASW and you should find some papers. Interestingly enough, the method > >was developed by earthquake folks and is being adapted by engineers, > >even down to testing concrete pavement. > >-- > >Doug Crice web site http://www.georadar.com > >GeoRadar Inc. e-mail dcrice@............ > >19623 Via Escuela Drive phone 408-867-3792 > >Saratoga, CA 95070 USA fax 408-867-4900 > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Re: Calibrating my Lehman using integration - the answer(long). Date: Sun, 14 Mar 1999 22:36:07 -0700 Larry- > The event produced a peek acceleration of 2.634 cm / sec * sec or 2.685 mg > (1g = 980.665 cm / sec * sec). Edward then integrated the acceleration > event file and his program calculated a peek velocity of .07191 cm / sec. > So the event produced a peek velocity of .07191 cm / sec. We also high-passed both the FBA-23 and Lehman signals with a 6-pole Butterworth filter at 1 Hz. -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 From: Larry Cochrane Subject: Measuring coil / magnet sensitivity Date: Mon, 15 Mar 1999 01:29:57 -0800 All, Now that I have an idea of the sensitivity of my Lehman using the FBA-23 sensor and an earthquake, I would like to directly measure the sensitivity of the coil and magnet combination using some other approach. This way I can compare the two numbers. I can think of two ways of doing this. #1. Make some type of test rig that moves either the coil or magnet a known amount and at a known frequency. Measure the output across a 10 k resistor (my amp card has a 10 k resistor between the input and ground) using a scope. #2 I remember seeing a post from Sean -Thomas on using a DC voltage applied to the coil to measure the strength of the coil and magnet by how much weight it can move. I would think one could then calculate how much output the coil should produce across a 10 k resistor at a given frequency and amount of motion. Method # 1, I think, requires a little more work coming up with the test rig, but the output would be in volts / cm / sec. A test rig for method #2 sounds easier to make, but requires conversion to v / cm / sec. Not sure how to do that.... Anyone have any other suggestions on how one might go about doing this? Regards, Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: Re: Measuring coil / magnet sensitivity Date: Mon, 15 Mar 1999 08:55:40 -0500 Larry, The force constant in Newtons/Amp = the voltage constant in Volts / Meter/sec Brett >rig, but the output would be in volts / cm / sec. A test rig for method #2 >sounds easier to make, but requires conversion to v / cm / sec. Not sure >how to do that.... > >Anyone have any other suggestions on how one might go about doing this? > >Regards, >Larry Cochrane >Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: Reading Seismograms Date: Mon, 15 Mar 1999 07:33:06 -0700 (MST) On Sat, 13 Mar 1999, barry lotz wrote: > I like your equation. It seems possible for one to take their > previously recorded events and perform FFTs on the P,S and Surface waves. > Winquake allows this. Then somehow incorporate the results into a distance > function. The problem I see with my sensors is that the different phases > respond differently depending on the epicenter's geographic location. > Larry- does you FFT routine allow for a summation of the responses at the > various frequencies? People have gotten pretty complicated when it comes to measuring the slope of the amplitude vs frequency plots. One guy was even pushing some kind of "Bayesian" technique... Of course, I have never been convinced that these fancier statistical/probability models give any better information than a simple regression. What you could do, Barry, if you are interested, is write your own code or modify somebody else's to perform both the FFT and the fit. To be consistent you would have to choose a good frequency window for every event to compare the relative differences. These types of subroutines are extremely common! I haven't tried Larry's new save to ascii feature yet, but I am itching to get around to trying it. One thing to remember though is that you should use ln instead of log for the amplitudes... ****************************************************************************** John Hernlund E-mail: 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 From: John Hernlund Subject: Earthquakes (fwd) Date: Mon, 15 Mar 1999 07:38:32 -0700 (MST) Does anyone have any Australian quake info sites? ---------- Forwarded message ---------- Date: Mon, 15 Mar 1999 17:09:13 +1100 From: The Condon's To: hernlund@....... Subject: Earthquakes Hi!! I live in Australia and was wondering if you knew where is could get information about recent seismic activity in particular areas. I was with some friends the other evening and we were sure we felt a tremor but don't know where to look to find out. I can only find American sites. Anything you know that could assist me would be wonderful. Thankyou for your time, Nikkie _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Roger Baker Subject: Re: Measuring coil / magnet sensitivity Date: Mon, 15 Mar 1999 09:37:02 -0600 Friends, From my experience with my Hi-Q vertical at least, I tend to think a good primary calibration approach is to change the vertical vector force of gravity with a slight and measured tilt at a known frequency, and once this response is measured and known, to reference to this calibration by subsequently flipping, or rotating with a gearmotor to generate a slow sine wave, a ceramic magnet at some fixed distance from the seismo at the appropriate frequency. Obviously no seismograph should be sensitive to external magnetic fields in theory, but I think in practice they nearly all are, well enough for this to work. With a vertical instrument sensitive down to DC like the Hi-Q, earth tides themselves can also be used for calibration. Some details on magnet flipping are at http://www.eden.com/~rcbaker and I think calibrated tilt techniques are in the archives somewhere. --Yours, Roger At 01:29 AM 3/15/99 -0800, you wrote: >All, > >Now that I have an idea of the sensitivity of my Lehman using the FBA-23 >sensor and an earthquake, I would like to directly measure the sensitivity >of the coil and magnet combination using some other approach. This way I >can compare the two numbers. I can think of two ways of doing this. > >#1. Make some type of test rig that moves either the coil or magnet a known >amount and at a known frequency. Measure the output across a 10 k resistor >(my amp card has a 10 k resistor between the input and ground) using a scope. > >#2 I remember seeing a post from Sean -Thomas on using a DC voltage >applied to the coil to measure the strength of the coil and magnet by how >much weight it can move. I would think one could then calculate how much >output the coil should produce across a 10 k resistor at a given frequency >and amount of motion. > >Method # 1, I think, requires a little more work coming up with the test >rig, but the output would be in volts / cm / sec. A test rig for method #2 >sounds easier to make, but requires conversion to v / cm / sec. Not sure >how to do that.... > >Anyone have any other suggestions on how one might go about doing this? > >Regards, >Larry Cochrane >Redwood City, PSN > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Canie Subject: Re: Earthquakes (fwd) Date: Mon, 15 Mar 1999 07:49:26 -0800 At 07:38 AM 3/15/99 -0700, John Hernlund wrote: >Does anyone have any Australian quake info sites? Here are some New Zealand sites, there may be a link to Australia somewhere: http://www.gns.cri.nz/news/earthquakes/recent_quakes.html http://www.rses.vuw.ac.nz/seismology/igns_backlog.html Western Australia PSN: http://iinet.net.au/~ajbv/ Canie > >---------- Forwarded message ---------- >Date: Mon, 15 Mar 1999 17:09:13 +1100 >From: The Condon's >To: hernlund@....... >Subject: Earthquakes > >Hi!! I live in Australia and was wondering if you knew where is could >get information about recent seismic activity in particular areas. I was >with some friends the other evening and we were sure we felt a tremor >but don't know where to look to find out. I can only find American >sites. Anything you know that could assist me would be wonderful. >Thankyou for your time, > Nikkie > > >_____________________________________________________________________ > >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 From: S-T Morrissey Subject: calibrations Date: Mon, 15 Mar 1999 13:39:05 -0600 (CST) Larry, Brett has pointed out the handy equilavence between volts/meter/second and Newtons/ampere. For calibrating a vertically suspended coil/magnet, adding a small additional mass to depress the boom and then using a potentiometer and a battery to apply a DC current to recenter it will give the coil constant within the accuracy of the meter and how well you can determine the zero position (I use a VRDT to do this on large long-period seismometers). For a horizontal like the Lehman, we rig a length of thread from the boom/mass/coil to the frame, and hang the test mass in the middle, making exactly a 45 degree angle in the center. This applies half the mass as a horizontal force to the boom, which can then be recentered as above, giving a force per unit of current. Then the weight in Kgrams is multiplied by g (9.806m/sec^2) and divided by the current in Amperes to get Newtons/Ampere. (actually grams*g/milliamperes gives the same result). When I determine the constant of the 10" speaker by force balance, 1 gram is balanced by 0.755ma, for a constant of 12.988 N/A. Another way to estimate the the constant of a coil is to count the turns and determine the strength B of the magnetic field in gauss. Estimate the length L of the winding IN CM by multiplying the # of turns by the mean circumference. Then G = B * L *10 **-6 N/A. For the 8-ohm stereo speaker I use, there are 162 turns at a mean diameter of 3.95cm, and the flyer says the field is 7500 gauss, so the constant is 15.08 N/A. When I determine the constant by force balance, I get a constant of 12.988 N/A, which probably means that not all the winding is within the magnetic field, which is the case. (The length L can also be determined by knowing the wire size and the resistance and looking it up in a table of wire parameters). This second method can be applied to the Lehman coil if the strength of the magnetic field can be determined. How much of the winding is within how much field is problematical. One can also directly calculate the movement of the boom/mass that results from applying a small tilt to the base (if the natural period is known). (this is a repeat of a note from Feb 15). Re: tilt sensitivity of horizontal seises: Regarding the recent question of finding a suitable site for a Lehman type horizontal seismometer: the problem is the extreme tilt sensitivity of a horizontal compared to a vertical sensor of the same period. In a nutshell, the tilt sensitivity of the vertical is proportional to the square of the tilt angle, while a horizontal is sensitive to the angle itself. Since we are dealing with small angles measured in radians, the squared value is much smaller, so the horizontal is much more sensitive. The formula for the tilt sensitivity of the horizontal pendulum: (which can be used to calibrate the displacement detector) z = (g * Tn^2 / 4 * pi^2) * phi where z is the horizontal displacement of the mass, Tn is the natural period, and phi is the tilt of the base at right angles to the boom, again measured in radians. g = 980cm/sec^2; z = cm. As an example: from experience in repeatedly adjusting the old S5100 for about 1mm of boom displacement: the base is 500 mm, so the tilt from 1/100 turn of the screw ( which is 0.008 mm) is 0.008/500 = 0.000016 radian. If Tn = 15 seconds, the mass will move 0.89 mm, which is close to what is observed. For the garage floor site, if we assume a 15 second horizontal seis and that the floor tilts by 0.0001 radian (there are 2*pi radians in 360 degrees, so a radian is 57.3 degrees, so our floor is tilting only 0.0057 degree.) It doesn't sound like much, but the seismometer mass will move 5.5 mm because of it. Or if the output is measured at 55 microns (displacement), the floor tilted one microradian. For a vertical seismometer, tilting the base will change the force of gravity that is normally exactly parallel to the force of the spring, reducing it slightly. The vertical formula is: z = (g * Tn^2 / 8 * pi^2) * phi^2 For our floor tilt example above, the angle (0.0001 radian) is squared, so the mass of the vertical will only move 0.275 MICRONS due to the same 0.0001 rad. tilt. This effect is often used to absolutely calibrate vertical displacement sensors, such as gravimeters and VBB instruments on large (1 meter triangles) tilt tables with differential micrometers. This effect of gravity is also used to install vertical VBB sensors to match the calibration done at the factory. This is done by tilting the base to find the "maximim gravity" position of the tilt of the base, where the displacement detector reads a minimum value (down), which is then the same condition as when the factory calibration is done. 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 From: Phil Schmidt Subject: Re: Earthquakes (fwd) Date: Tue, 16 Mar 1999 10:37:46 +0900 At 07:38 AM 3/15/99 -0700, you wrote: G'day Nikkie I live in South Australia which on average has a couple of small earth quakes per year measuring between 4 - 5 on the scale. I use the site provided by the Primary industries and Resources South Australia PIRSA which can be found at http://www.mines.sa.gov.au/earthquakes.htm Other than that you can find lots of useful links at the Seismology Research Centre in Melbourne which has links to most other useful earth quake information this site can be found at http://www.seis.com.au/ Hope this of some help to you Cheers Philip Schmidt (SA) >Does anyone have any Australian quake info sites? > >---------- Forwarded message ---------- >Date: Mon, 15 Mar 1999 17:09:13 +1100 >From: The Condon's >To: hernlund@....... >Subject: Earthquakes > >Hi!! I live in Australia and was wondering if you knew where is could >get information about recent seismic activity in particular areas. I was >with some friends the other evening and we were sure we felt a tremor >but don't know where to look to find out. I can only find American >sites. Anything you know that could assist me would be wonderful. >Thankyou for your time, > Nikkie > > >_____________________________________________________________________ > >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 From: Angel Rodriguez Subject: Re: Reading Seismograms Date: Mon, 15 Mar 1999 20:28:24 -0500 Hi, I have spend about an hour looking for where I might be able to buy this document. I started with the GPO pages and go nowhere, then went the used and new bookstores and still nowhere. I someone has it I would be glad to pay for the coping and shipping. thanks, angel At 08:04 PM 03/12/1999 -0600, you wrote: >Dick: > >The document you need is the: > >"Principles Underlying the Interpretation of Seismograms" >Special publication 254, revised (1966) edition, >Prepared by Frank Neumann, Geophysicist, Coast and Geodetic Survey > >U.S. govt. printing office, Wash, DC, 20402, > >This 50 page report also includes a set of travel-time tables >for 4 different depths as well as sample seismograms. It is the >definitive document for reading analog seismogram records. > >But, as has been pointed out, only experience can bring familiarity >with the data. After 30 years of reading seismograms, I can >generally tell whether and event is in Alaska or South America >at first glance; we sometimes bet on the guessed location, but >sometimes we are thrown way off because of a rare depth phase >or whatever. An estimate of the arrival azimuth and a great-circle >map of the world centered on the station also helps, since quakes >only occurr in seismogenic zones. > >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) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: Reading Seismograms Date: Mon, 15 Mar 1999 19:41:47 -0700 (MST) On Mon, 15 Mar 1999, Angel Rodriguez wrote: > I have spend about an hour looking for where I might be able to buy this > document. I started with the GPO pages and go nowhere, then went the used > and new bookstores and still nowhere. I someone has it I would be glad to > pay for the coping and shipping. I checked ASU libraries' catalog and they don't have it here, which means it is fairly rare... I'll check with some other people and see if they know it, and if it is any better than what you have already read... We do have several others: Author Kulhk, Ota. Title Anatomy of seismograms / Ota Kulhk. Publisher Amsterdam ; New York : Elsevier, 1990. Note "For the IASPEI/Unesco Working Group on Manual of Seismogram Interpretation." Gov doc # Y 3.N 88:25/4822 Title Broad band seismic data analysis / prepared by J.A. Carter [et al.]. Publisher Washington, DC : Division of Engineering Safety, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, 1987. Note "Rondout Associates, Incorporated." Distributed to depository libraries in microfiche. "Date published: April 1987." "NUREG/CR-4822." "RA." Author Simon, Ruth B., 1917- Title Earthquake interpretations : a manual for reading seismograms Publisher Los Altos, Calif. : W. Kaufmann, 1981 I'll check into these this week, and if they are worth the trouble I'll see if anyone wants photocopies... ****************************************************************************** John Hernlund E-mail: 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 From: Ted Blank Subject: Re: Reading Seismograms Date: Mon, 15 Mar 1999 21:28:37 -0800 (PST) I for one would be very grateful if someone skilled in the art of interpretation of seismograms would volunteer to present some of the basic and maybe advanced topics at the next PSN meeting. Ruth Simon's book has always seemed like you needed to have someone teaching you what each trace was trying to say. It is not obvious to the beginner. Ted Blank San Jose, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Ted Blank Subject: Re: Pile driving near me... Date: Mon, 15 Mar 1999 21:37:58 -0800 (PST) If you record long enough, maybe the crew will move the piledriver around the site enough to give you the same effect as moving the sensor. Ted Blank San Jose, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Ted Blank Subject: Re: Reading Seismograms Date: Mon, 15 Mar 1999 21:40:42 -0800 (PST) Using Larry's WinQuake option of displaying the expected arrival times of several phases is a "high tech" way of doing this. I agree the feedback is the key to learning. Ted Blank San Jose, California On Mon, 15 Mar 1999, John Taber wrote: > Dick > You wrote: > >Thanks for the information about earth models. My question is a tad more > >basic. When confronted with a seismogram what is the best way to approach > >making picks IF YOU DON'T KNOW THE HYPOCENTER. Are there characteristic > >shapes and relationships that would let one determine a P from a Pp and > >even something so simple as an S wave. After all they must have used the > >eyeball approach before the days of the internet or telemetry. > > Here is how students were taught when I was at Lamont. I expect it is > similar to the way picks were done before computers > or telemetry. It requires a set of standardized travel time plots. > > 1.Take the helicorder record from one of the components > and lay it on the table. Take a piece of > paper tape (like what was used in computer punch tape, for those who > can remember that far back) and line it up along the seismogram. > > 2.Mark the first arrival on the tape and then begin making marks on the > tape at each point on the seismogram that appears to correspond to a > new phase. > > 3. From the relative size of the surface waves (the usually large, > late arriving waves) compared to the earlier arrivals make a > crude guess as to depth, ie 33, 100, 300, 600 km. The smaller the > surface waves the deeper the guess. > > 4. Select the travel time plot that corresponds to that depth. > The travel time plots were printed at the same time scale as the > helicorder, and had time vs distance curves for each of the major phases. > > 5. Slide your paper tape along the distance axis until you get the > best match between your picks and the phases on the plot. > If there was not a good match then try a travel time plot with a > different depth. Compare with phases selected on the other components. > This is the main iterative step where one learns to identfy > different phases. > > This gives you an estimate of distance and depth. > > You can then get an estimate of azimuth by looking at the > polarity of the first arrival on all 3 components. For example, > f you get positive up, N, and E, then > the earthquake came from azimuth between 180 and 270 degrees. > > You then go to a globe and using a knowledge of the global distribution > of earthquakes, estimate the likely source of the earthquake. > > > With some practice you can usually come close to the actual location > > > John Taber > > > > _____________________________________________________________________ > > 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 From: S-T Morrissey Subject: Re: Reading Seismograms Date: Tue, 16 Mar 1999 01:05:18 -0600 (CST) Angel and co. Re: manual for interpreting seismograms. I really don't want to get into the printing business, but if the manual cannot be found, I'll figure what the SASE cost for double-sided copies would be and let you know. My current problem is that my desk copy of the manual is missing the travel time tables, so I have to locate my original or find one. It was rather popular in our department when Otto Nuttli used it for his classes. As John Taber described, Otto was prone to grabbing a strip of paper from the calculator in the office and going right to the seismic recording drum and marking/timing phases as an event unfolded in real time. More later.... 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 From: Phil Schmidt Subject: number or seismograps Date: Tue, 16 Mar 1999 18:46:28 +0900 G'day All I was wondering if anybody could tell me if it would be a good idea to place two horizontal seismographs one pointing east-west and another pointing north-south. I ask this because I am soon to set up my own seismographs in my back yard as soon as I have finished my studies as an electronic technician. Could someone also please tell me what is the best sample rate for any digital recording of earthquakes. if anybody could help it would be great. Thanks Philip Schmidt (South Australia) _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "James M Hannon" Subject: Re: Reading Seismograms Date: Tue, 16 Mar 1999 08:10:30 -0600 I thought I would try and find some reference to "Principles Underlying the Interpretation of Seismograms" no luck, but I did find this online document http://www.seismo.com/msop/msop79/msop.html which appears to be quite interesting. Also since "Principles Underlying the Interpretation of Seismograms" is an old government publication there should be no restrictions to someone digitizing it and putting it on the web. Jim Hanon _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: bzimmerman@............ Subject: Pennsylvania Quake ? Date: Tue, 16 Mar 1999 10:59:59 -0500 (EST) I picked up what looks like a significant event today at about 12:45 UTC. My clocks are not locked so I can not be sure of exact arrival times. I have checked a few "live" seismographs which do not show anything at this time, suggesting a local rather than teleseismic event. I am thinking that this may be an aftershock of the Sept. 25 Pymatuning, Pennsylvania/Ohio quake. Can anyone provide any additional information/help ? Brian Zimmerman _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Canie Subject: Re: Pennsylvania Quake ? Date: Tue, 16 Mar 1999 08:20:01 -0800 At 10:59 AM 3/16/99 -0500, bzimmerman@............ wrote: > >I picked up what looks like a significant event today at about 12:45 UTC. >My clocks are not locked so I can not be sure of exact arrival times. It appears to be this one:? 99/03/16 12:50:48 49.65N 66.39W 18.0 5.0Lg C GASPE PENINSULA, CANADA Canie > >I have checked a few "live" seismographs which do not show anything at >this time, suggesting a local rather than teleseismic event. I am >thinking that this may be an aftershock of the Sept. 25 Pymatuning, >Pennsylvania/Ohio quake. > >Can anyone provide any additional information/help ? > >Brian Zimmerman > > >_____________________________________________________________________ > >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 From: bzimmerman@............ Subject: Re: Pennsylvania Quake ? Date: Tue, 16 Mar 1999 11:27:22 -0500 (EST) Thanks, after my first look at the my records I would have swore it was closer and larger. Swamped both instruments so I couldn't pick the P-S waves. BZ On Tue, 16 Mar 1999, Canie wrote: > At 10:59 AM 3/16/99 -0500, bzimmerman@............ wrote: > > > >I picked up what looks like a significant event today at about 12:45 UTC. > >My clocks are not locked so I can not be sure of exact arrival times. > > It appears to be this one:? > 99/03/16 12:50:48 49.65N 66.39W 18.0 5.0Lg C GASPE PENINSULA, CANADA > > Canie > > > > >I have checked a few "live" seismographs which do not show anything at > >this time, suggesting a local rather than teleseismic event. I am > >thinking that this may be an aftershock of the Sept. 25 Pymatuning, > >Pennsylvania/Ohio quake. > > > >Can anyone provide any additional information/help ? > > > >Brian Zimmerman > > > > > >_____________________________________________________________________ > > > >Public Seismic Network Mailing List (PSN-L) > > > >To leave this list email listserver@.............. with the body of the > >message: leave PSN-L > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Karl Cunningham Subject: Re: number or seismograps Date: Tue, 16 Mar 1999 08:53:29 -0800 Hi Phil -- The more seismographs the merrier! If you have two horizontal instruments, N-S and E-W would be good choices. It helps correlate the data since you have orthagonal axes. Even better is to include a vertical instrument -- then you have yet another orthagonal axis. Vertical and horizontal instuments have different sensitivities to various kinds of waves, but this is an area where my knowledge is rather sketchy. Perhaps someone else would care to elaborate. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... At 06:46 PM 3/16/99 +0900, you wrote: >G'day All > >I was wondering if anybody could tell me if it would be a good idea to >place two horizontal seismographs one pointing east-west and another >pointing north-south. I ask this because I am soon to set up my own >seismographs in my back yard as soon as I have finished my studies as an >electronic technician. Could someone also please tell me what is the best >sample rate for any digital recording of earthquakes. > >if anybody could help it would be great. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Re: Pennsylvania Quake ? Date: Tue, 16 Mar 1999 12:02:08 -0700 Brian & Canie- I haven't heard anything yet myself other than what you have posted in these two message, but I'll forward it to the Pymatuning email list. -Edward Canie wrote: > At 10:59 AM 3/16/99 -0500, bzimmerman@............ wrote: > > > >I picked up what looks like a significant event today at about 12:45 UTC. > >My clocks are not locked so I can not be sure of exact arrival times. > > It appears to be this one:? > 99/03/16 12:50:48 49.65N 66.39W 18.0 5.0Lg C GASPE PENINSULA, CANADA > > Canie > > > > >I have checked a few "live" seismographs which do not show anything at > >this time, suggesting a local rather than teleseismic event. I am > >thinking that this may be an aftershock of the Sept. 25 Pymatuning, > >Pennsylvania/Ohio quake. > > > >Can anyone provide any additional information/help ? > > > >Brian Zimmerman > > > > > >_____________________________________________________________________ > > > >Public Seismic Network Mailing List (PSN-L) > > > >To leave this list email listserver@.............. with the body of the > >message: leave PSN-L > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Nick & Sophie Caporossi Subject: Re: Pennsylvania Quake ? Date: Tue, 16 Mar 1999 15:41:01 -0500 Hi Brian: Yes I did picked up an event at about that time. The "p" waves arrived here,(East Brunswick, NJ) at 12:53 utc. I believe it was a 5.0Lg at Gaspe Peninsula, Canada. It's about 747 miles from my station. Nick At 10:59 AM 3/16/99 -0500, you wrote: > >I picked up what looks like a significant event today at about 12:45 UTC. >My clocks are not locked so I can not be sure of exact arrival times. > >I have checked a few "live" seismographs which do not show anything at >this time, suggesting a local rather than teleseismic event. I am >thinking that this may be an aftershock of the Sept. 25 Pymatuning, >Pennsylvania/Ohio quake. > >Can anyone provide any additional information/help ? > >Brian Zimmerman > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: Re: number or seismograps Date: Tue, 16 Mar 1999 17:15:14 -0600 (CST) Philip and Bruce and co. The prefered choice of a single instrument seismograph station is to have a vertical instrument. These respond very well to the compressional P-wave, and usually an earthquake has enough S-wave energy that is vertically polarized that it records well. Also, for the reasons I discussed yesterday, a vertical is much less sensitive to tilt noise than a horizontal, so it works well in an urban environment, like the basement of a residence. Even in remote sites, a vertical can be installed in a plastic "pipe vault" in ordinary soil, while a horizontal needs a concrete pad to have any useful stability, even for a 1-hz seismometer. When two horizontals are available, the NS and EW orientaions are preferred. The main reason to use a horizontal is to record the S-wave, which has a polarization at right angles to the direction of propagation of the wave. So if the event is in South America, we will see a strong S on the EW sensor here in St. Louis, whereas a California event will have a strong NS S-wave. When we set up the telemetry network in the Aleutians, we used only two components or seismometers at each site, a vertical and an EW horizontal, since most of the quakes were to the south of the islands, and would show little S-wave energy from a NS sensor. This allowed us to get 16 stations within our 32-channel telemetry configuration rather than 11. Regarding the sampling rate: for data of a given frequency, the minumum rate is referred to as the Nyquist frequency, which is twice the data frequency. SO if you want to record 20 hz data, a minumum sampling rate if 40 hz is needed, so use Larry's 50 sample/sec card. In the global array of broadband stations, the sample rate is 20 for the VBB data stream, which is suitable for teleseismic and near regional events (the farther away a quake is, the more the frequency of its waves disperses toward longer periods). For local events (and the non-proliferation test ban verification sensors) a 40 sample per second rate is used. The trade-off comes when one considers how the data is stored; high sample arates quickly fill up large files. 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 From: Dick Webb Subject: Re: Reading Seismograms Date: Tue, 16 Mar 1999 21:40:20 -0500 Hey Sean, could youn make copies available for a fee. I must have spent two hours searching for a source and got no where. Dick At 08:28 PM 3/15/99 -0500, you wrote: >Hi, > >I have spend about an hour looking for where I might be able to buy this >document. I started with the GPO pages and go nowhere, then went the used >and new bookstores and still nowhere. I someone has it I would be glad to >pay for the coping and shipping. > >thanks, > >angel > >At 08:04 PM 03/12/1999 -0600, you wrote: >>Dick: >> >>The document you need is the: >> >>"Principles Underlying the Interpretation of Seismograms" >>Special publication 254, revised (1966) edition, >>Prepared by Frank Neumann, Geophysicist, Coast and Geodetic Survey >> >>U.S. govt. printing office, Wash, DC, 20402, >> >>This 50 page report also includes a set of travel-time tables >>for 4 different depths as well as sample seismograms. It is the >>definitive document for reading analog seismogram records. >> >>But, as has been pointed out, only experience can bring familiarity >>with the data. After 30 years of reading seismograms, I can >>generally tell whether and event is in Alaska or South America >>at first glance; we sometimes bet on the guessed location, but >>sometimes we are thrown way off because of a rare depth phase >>or whatever. An estimate of the arrival azimuth and a great-circle >>map of the world centered on the station also helps, since quakes >>only occurr in seismogenic zones. >> >>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) > >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 From: Doug Crice Subject: Re: number or seismograps Date: Tue, 16 Mar 1999 20:06:45 -0800 I am at a trade show in Oakland this week (the Society for the Application of Geophysics to Engineering and Environmental Problems) and R.T. Clark has a booth there. They have some 1 Hz vertical seismometers available, some Teledyne S-500 for $275 and some Geospace (I forget the number) tested for $375. Of course it's not in keeping with the PSN ambience to buy a seismometer, but there they are. -- Doug Crice web site http://www.georadar.com GeoRadar Inc. e-mail dcrice@............ 19623 Via Escuela Drive phone 408-867-3792 Saratoga, CA 95070 USA fax 408-867-4900 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Seisguy@....... Subject: Moderate earthquake jolts Sydney Date: Tue, 16 Mar 1999 22:47:58 EST Moderate earthquake jolts Sydney SYDNEY, March 17 (Reuters) - Sydney was shaken on Wednesday by a moderate earthquake registering 4.5 on the Richter scale but there were no immediate reports of major damage, officials said. ``It was at 12:58 p.m. (0158 GMT),'' said Amy Brown of the Royal Melbourne Institute of Technology's Seismology Research Centre. ``There are no reports of damage,'' she told Reuters by telephone. The quake was centred near Wilton, about 70 km (43 miles) south of Australia's largest city, but could be clearly felt in central Sydney. Australian Broadcasting Corporation (ABC) radio reported that about 1,000 homes were left without electricity after the quake. Several callers to reported minor damage to their homes. ``The house sort of moved sideways...and all the birds went dead quiet, there wasn't a sound outside,'' one unidentified caller told ABC radio. An earthquake measuring 5.6 on the Richter scale hit the steel city of Newcastle north of Sydney in December 1989, killing 12 people and causing widespread damage. 22:00 03-16-99 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Dennis W. Pope" Subject: Ota Kulhanek Book Date: Wed, 17 Mar 1999 07:01:01 -0500 The Ota Kulhanek book on interpreting seismograms can be purchsed from Amazon, but it will set you back $142.00. It is also a special order -- they have to hammer out the gold leaf. = Dennis _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Wayne Abraham J73WA Subject: Re: Reading Seismograms Date: Wed, 17 Mar 1999 08:56:29 -0400 Hi all Because of all the mail that has been going around concerning Reading of Seismograms, I have added 2 books to the Dominica Public Seismic Network bookshelf. They are : Earthquake Interpretations: A manual for reading seismograms and Anat of Seismograms. You can have a look at them at: http://www.freeyellow.com/members6/dominicapsn/books.html Wayne _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Angel Rodriguez Subject: Re: Reading Seismograms Date: Wed, 17 Mar 1999 09:28:39 -0500 Hi Sean-Thomas, If you can get a good copy to me I will scan it and create an Acrobat PDF file or HTML doc and post it. As you know I live in Panama but will be in Seattle at the end if the month. Thanks, Angel At 01:05 AM 03/16/1999 -0600, you wrote: >Angel and co. > >Re: manual for interpreting seismograms. > >I really don't want to get into the printing business, but if the manual >cannot be found, I'll figure what the SASE cost for double-sided copies >would be and let you know. My current problem is that my desk copy of >the manual is missing the travel time tables, so I have to locate my >original or find one. It was rather popular in our department when Otto >Nuttli used it for his classes. As John Taber described, Otto was prone to >grabbing a strip of paper from the calculator in the office and going >right to the seismic recording drum and marking/timing phases as an >event unfolded in real time. > >More later.... > >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) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: VRDT transducer info Date: Wed, 17 Mar 1999 20:22:08 -0800 Sean Thomas Thanks for getting back to me. I'm a little confused ( as always) about your comment about feedback gain. I'll have to read it again. I thought your gains were much higher to get 1e6 v/m output. Are you separating the amplification string in multiply defined tasks? Oh by the way--- I made an LVDT and was able to calibrate it to 1e6+v/m. I was hoping to incorporate it in a triple feedback horizontal I just built along the lines of the sensor drawing you posted. I forget it's name right now. I had a real problem trying to keep it on scale. With the verticals one can move small weights but a horizontal a leveling screw just doesn't cut it when full scale is 0.0001". Maybe I'll turn it into a Force Balance sensor instead. Regards Barry _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Phil Schmidt Subject: New accelerometer Date: Thu, 18 Mar 1999 17:14:23 +0900 G'day All I have just received a email from analogue devices about there new and improved device called the ADXL105 which replaces the ADXL05. Heres part of the email. ********************************************* The ADXL105 - the replacement for the ADXL05 ********************************************* The ADXL105 (May '99 release date)is a high performance, high accuracy, and low cost single axis accelerometer. It measures accelerations with a full-scale range up to =B15g and significantly increases bandwidth and reduces noise versus previously available micromachined devices, such as the ADXL05. It will soon be available in both an industrial (-40C to +85C) and commercial (0 to +70) grades. For more information, There is also a Analogue devices White paper on using accelerometers for strong motion detection. This can be found at http://www.analog.com/publications/whitepapers/products/Seismart.html Hope this is of some interest to some of you. Cheeers Phil Schmidt _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Phil Schmidt Subject: Interesting Date: Thu, 18 Mar 1999 22:30:30 +0900 G'day All I found this company on the internet and it seems to sell data acquisition equipment and the like for the PC. If ou are interested take a look they can be found at http://www.iotech.com/index.html Cheers Phil Schmidt _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Francesco" Subject: R: New accelerometer Date: Sat, 20 Mar 1999 19:00:53 +0100 A simple thing: ADXL105 is a chip or a really accelerometer sensor? The data sheet on web site it's very accurate, but I don't undestand his = employment. Another problem: it' s need only Analog datalogger using his digital = output or it's possible to amp and convert the alternative analog outp. = with other systems (Larry's amp, a/d board etc.etc.)? Thank you for the suggest. Francesco Nucera - Italy -
A simple thing:  ADXL105 is a = chip or a=20 really accelerometer sensor?
The data sheet on web site it's very = accurate,=20 but I don't undestand his employment.
Another problem: it' s need only = Analog=20 datalogger using his digital output or it's possible to amp and convert = the=20 alternative analog outp. with other systems (Larry's amp, a/d board=20 etc.etc.)?
 
Thank you for the = suggest.
Francesco Nucera   - Italy = -
From: Wayne Abraham J73WA Subject: Volcanic Eruption Simulation Exercise Date: Thu, 18 Mar 1999 20:55:34 -0400 PSN To those of you who have been following the increased seismic activity on Dominica, the Government of Dominica has just released details of the simulation exercise to take place on March 25 which will test the newly developed Volcanic Eruption chapter of the National Disaster Preparedness plan. The entire news release is available on the Dominica Public Seismic Network website: http://www.freeyellow.com/members6/dominicapsn/pres1803.txt Don't forget to keep checking our website for updates at: http://www.freeyellow.com/members6/dominicapsn/ Wayne _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Rudolph Norvelle" Subject: placement of computer Date: Thu, 18 Mar 1999 19:49:32 -0800 When I finally get around to setting up my seismograph, it will be = in my garage and the computer will be in my den on the second floor of = my house. Will there be any problem with degradation of the signals over = the distance (about 30' overall). I will be using Larry Cochrane's = Boards in my computer. Any ideas out there? = Thanks in advance, = Rudy Norvelle
    When = I finally=20 get around to setting up my seismograph, it will be in my garage and the = computer will be in my den on the second floor of my house. Will there = be any=20 problem with degradation of the signals over the distance (about 30'=20 overall).  I will be using Larry Cochrane's Boards in my = computer. =20 Any ideas out there?
         &nb= sp;           &nbs= p;            = ;            =             &= nbsp;           &n= bsp;    =20 Thanks in advance,
         &nb= sp;           &nbs= p;            = ;            =             &= nbsp;           &n= bsp;    =20 Rudy Norvelle
From: barry lotz Subject: Re: placement of computer Date: Thu, 18 Mar 1999 20:40:05 -0800 Hi Rudy I run mine from my garage to the house, about the same distance. You should use a shielded cable to limit noise. You might make sure there is a line driver at the end of the board at your sensor. I hope this helps a little. Regards Barry Rudolph Norvelle wrote: > When I finally get around to setting up my seismograph, it will > be in my garage and the computer will be in my den on the second floor > of my house. Will there be any problem with degradation of the signals > over the distance (about 30' overall). I will be using Larry > Cochrane's Boards in my computer. Any ideas out > there? > Thanks in > advance, > Rudy Norvelle Hi Rudy
    I run mine from my garage to the house, about the same distance. You should use a shielded cable to limit noise. You might make sure there is a line driver at the end of the board at your sensor. I hope this helps a little.
 Regards
  Barry
 

Rudolph Norvelle wrote:

     When I finally get around to setting up my seismograph, it will be in my garage and the computer will be in my den on the second floor of my house. Will there be any problem with degradation of the signals over the distance (about 30' overall).  I will be using Larry Cochrane's Boards in my computer.  Any ideas out there?          &n bsp;                    &nb sp;                    &nbs p;                      ;  Thanks in advance,             &n bsp;                    &nb sp;                    &nbs p;                    Rudy Norvelle
From: "Jim Morrissey" Subject: crude seismograph design Date: Fri, 19 Mar 1999 01:58:17 -0500 Hi. I was wondering if anyone could supply me with details, or directions to details, for a homemade yet crude digital seismograph. I would like to monitor the motion of a trailer that will be pulled behind a vehicle. This motion is a result of the condition of the road surface on a particular section of pavement. It seems to me that a seismograph would be a perfect tool to measure road irregularities. However, I am concerned that "standard" seismographs are far too sensitive for this type of application? Any ideas? I would appreciate your response either good or bad news. Thanks for your time at this listserv, as you are the folks that know about these things. Jim M. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Re: placement of computer Date: Thu, 18 Mar 1999 23:20:35 -0800 Rudy, My amplifier card has an output capable of driving over 100 feet of coax wire. I use ~100 feet of 75 ohm cable TV wire between my amplifiers and the A/D cards. Regards, Larry Cochrane Redwood City, PSN At 07:49 PM 3/18/99 -0800, you wrote: >>>> ffff,ffff,0000 0000,0000,ffffWhen I finally get around to setting up my seismograph, it will be in my garage and the computer will be in my den on the second floor of my house. Will there be any problem with degradation of the signals over the distance (about 30' overall). I will be using Larry Cochrane's Boards in my computer. Any ideas out there? Thanks in advance, Rudy Norvelle <<<<<<<< _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Re: R: New accelerometer Date: Thu, 18 Mar 1999 23:42:29 -0800 Francesco, The ADXL type senors (and others on the market) are chip based accelerometers. In the silicon they etch a very small pendulum and all the electronics to make a forced balanced accelerometer. The problem is the old ADXL05 had very limited dynamic range and sensitivity. I do not see any info on either for the new chip. I guess we will have to wait until the data sheet comes out. If the new part has a dynamic range increase of 10 or more then it starts to become useful for a real strong motion sensor. The ADXL05 chips are at best a VERY strong motion sensor. It took a local M5.4 event to get something other then noise out of the ADXL05 device. My Amp card can be used to interface between the chip and the A/D converter. Basically one would use my board as a low pass filter and cable driver since the chips have amplification built in. Regards, Larry Cochrane Redwood City, PSN At 07:00 PM 3/20/99 +0100, you wrote: >>>> A simple thing: ADXL105 is a chip or a really accelerometer sensor? The data sheet on web site it's very accurate, but I don't undestand his employment. Another problem: it' s need only Analog datalogger using his digital output or it's possible to amp and convert the alternative analog outp. with other systems (Larry's amp, a/d board etc.etc.)? Thank you for the suggest. Francesco Nucera - Italy - <<<<<<<< _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: GPS and DSL Date: Fri, 19 Mar 1999 01:09:28 -0800 All, Recently I ran into the following "good deals". GPS Timing Receivers. In the process of getting a GPS timing receiver for one of our PSN station I found out that Motorola has reduced the cost of the GPS receiver compatible with SDR. Last year the GPS receiver I used to develop the code to cost $199.00. It now costs $171.00 in small numbers. The active antenna is still around $50.00. I bought the receiver and antenna at Synergy Systems (www.synergy-gps.com). For more information on GPS and SDR see the web page at http://www.seismicnet.com/sdrdocs/gps.htm. DSL Internet Connection. If you surf the web a lot and live in an area serviced by PacBell you might check into seeing if you can get a DSL connection into the Internet. For less then $50.00 a month one can get literally T1 (a high speed link normally used by businesses and costing over $1K per month) download speeds! In December of last year I moved my Internet connection over to DSL with a 384 k bit incoming / 128 k bit outgoing connection with 5 IP address. The cost was going to be ~137.00 per month, only a little over the $105.00 per month I was paying for a 28k bit (in and out going) connection. The increase in bandwidth was great. In late Jan. or early Feb. PacBell announced new pricing for their DSL services. For ~$80.00 a month (~50.00 for a single IP address, I have 5 IP numbers so the cost is a little higher) I could get my service changed and get 384 + / 128 bit connection. The + means they would increase the incoming bandwidth to 1+ meg bit rate, if my line connection can handle it. There is a ~3 mile limit on the distance DSL will work using the standard phone line wires between the you and the central office. The farther away, the less bandwidth you can get. If I remember right I'm about 2 miles from the central office. Since it looked I was getting more for less I called PacBell and changed my service. It took several more calls to PacBell to get them to remove the bandwidth limitation on my connection. Last Friday they finally called me to let me know that the bandwidth should be higher, if my the connection can handle it. I have access to several systems with very good connectivity on the Internet. After doing some download tests using FTP on large files I determined I was getting download speeds peaking at 1.2 meg bit (~152 meg byte per sec.) download speeds. I can now download a 30 meg byte file in about 3 minutes. With my old 28.8k connection it would take over 2 hours to download the same file. With DSL you can also setup your own Web and FTP servers since you get a static IP address assigned too you. As they say on the Internet, I don't work for Synergy Systems or PacBell.... -Larry Cochrane Redwood City _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Al Allworth" Subject: Re: crude seismograph design Date: Fri, 19 Mar 1999 02:43:49 -0800 Hi Jim, I think one of several surplus geophones available should do the job. They sell at prices below $10.00. All Electronics in L.A. had some. I don't remember the other places that have been mentioned. Someone else will probably respond with other suggestions for sources. ____________________________________ Al Allworth allworth@.............. Gold Beach On The Beautiful Southern Oregon Coast ____________________________________ ----- Original Message ----- From: Jim Morrissey To: Sent: Thursday, March 18, 1999 10:58 PM Subject: crude seismograph design > Hi. > > I was wondering if anyone could supply me with details, or directions to > details, for a homemade yet crude digital seismograph. I would like to > monitor the motion of a trailer that will be pulled behind a vehicle. This > motion is a result of the condition of the road surface on a particular > section of pavement. > > It seems to me that a seismograph would be a perfect tool to measure road > irregularities. However, I am concerned that "standard" seismographs are far > too sensitive for this type of application? Any ideas? I would appreciate > your response either good or bad news. > > Thanks for your time at this listserv, as you are the folks that know about > these things. > > Jim M. > > > > _____________________________________________________________________ > > 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 From: Phil Schmidt Subject: Re: crude seismograph design Date: Fri, 19 Mar 1999 21:35:36 +0900 At 01:58 AM 3/19/99 -0500, you wrote: G'day Jim Just a thought could you use a accelerometer for this particular application since your trailer might be exposed to shocks and suddden changes rather than suttle movements. Being a student of the electronics trade I have found that several companies on the internet send you, upon request free samples of there of some of there products it just so happens that Analogue devices do this so you might be able to get a free sample or samples of accelerometers off of them. Just a thought Cheers Phil Schmidt >Hi. > >I was wondering if anyone could supply me with details, or directions to >details, for a homemade yet crude digital seismograph. I would like to >monitor the motion of a trailer that will be pulled behind a vehicle. This >motion is a result of the condition of the road surface on a particular >section of pavement. > >It seems to me that a seismograph would be a perfect tool to measure road >irregularities. However, I am concerned that "standard" seismographs are far >too sensitive for this type of application? Any ideas? I would appreciate >your response either good or bad news. > >Thanks for your time at this listserv, as you are the folks that know about >these things. > >Jim M. > > > >_____________________________________________________________________ > >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 From: Phil Schmidt Subject: Lehman pivot point Date: Fri, 19 Mar 1999 21:38:47 +0900 G'day All I was wondering if anybody could tell me whether it makes any great difference if the pivot point of a Lehman type seismometer boom is a knife edge like many of the articles say or a single point like the tip of a nail. Cheers Phil Schmidt _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Walt Williams" Subject: PSN-L: crude seismograph design & more Date: Fri, 19 Mar 1999 03:15:57 -0800 Hello Jim, Please visit my (filtered from PSN-L postings) fairly upto date geophone archive at: http://www.pacificnet.net/~dfheli/geophon.html for information on geophones, where to buy them, their usage, application and applicable electronics. I recommend Larry Cochrane's amplifier boards which are inexpensive, very well made and work great! Best Wishes, Walt Williams, 99.03.19 OSR dfheli@.............. ============================ From: "Jim Morrissey" To: Subject: crude seismograph design Date sent: Fri, 19 Mar 1999 01:58:17 -0500 Send reply to: PSN-L Mailing List Hi. I was wondering if anyone could supply me with details, or directions to details, for a homemade yet crude digital seismograph. I would like to monitor the motion of a trailer that will be pulled behind a vehicle. This motion is a result of the condition of the road surface on a particular section of pavement. It seems to me that a seismograph would be a perfect tool to measure road irregularities. However, I am concerned that "standard" seismographs are far too sensitive for this type of application? Any ideas? I would appreciate your response either good or bad news. Thanks for your time at this listserv, as you are the folks that know about these things. Jim M. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Doug Crice Subject: Re: crude seismograph design Date: Fri, 19 Mar 1999 06:32:59 -0800 Most geophones are going to be too sensitive to be used in a moving vehicle. The moving mass travel is typically 0.1 inch and they will move enough to hit the stops on any road rough enough for you to want to measure the vibrations. I vote for the accellerometer, especially since acceleration is the thing you are interested in for this type of study. Phil Schmidt wrote: > > At 01:58 AM 3/19/99 -0500, you wrote: > G'day Jim > > Just a thought could you use a accelerometer for this particular > application since your trailer might be exposed to shocks and suddden > changes rather than suttle movements. Being a student of the electronics > trade I have found that several companies on the internet send you, upon > request free samples of there of some of there products it just so happens > that Analogue devices do this so you might be able to get a free sample or > samples of accelerometers off of them. > > Just a thought > > Cheers Phil Schmidt > >Hi. > > > >I was wondering if anyone could supply me with details, or directions to > >details, for a homemade yet crude digital seismograph. I would like to > >monitor the motion of a trailer that will be pulled behind a vehicle. This > >motion is a result of the condition of the road surface on a particular > >section of pavement. > > > >It seems to me that a seismograph would be a perfect tool to measure road > >irregularities. However, I am concerned that "standard" seismographs are far > >too sensitive for this type of application? Any ideas? I would appreciate > >your response either good or bad news. > > > >Thanks for your time at this listserv, as you are the folks that know about > >these things. > > > >Jim M. > > > > > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Doug Crice Subject: Re: crude seismograph design Date: Fri, 19 Mar 1999 06:32:59 -0800 Most geophones are going to be too sensitive to be used in a moving vehicle. The moving mass travel is typically 0.1 inch and they will move enough to hit the stops on any road rough enough for you to want to measure the vibrations. I vote for the accellerometer, especially since acceleration is the thing you are interested in for this type of study. Phil Schmidt wrote: > > At 01:58 AM 3/19/99 -0500, you wrote: > G'day Jim > > Just a thought could you use a accelerometer for this particular > application since your trailer might be exposed to shocks and suddden > changes rather than suttle movements. Being a student of the electronics > trade I have found that several companies on the internet send you, upon > request free samples of there of some of there products it just so happens > that Analogue devices do this so you might be able to get a free sample or > samples of accelerometers off of them. > > Just a thought > > Cheers Phil Schmidt > >Hi. > > > >I was wondering if anyone could supply me with details, or directions to > >details, for a homemade yet crude digital seismograph. I would like to > >monitor the motion of a trailer that will be pulled behind a vehicle. This > >motion is a result of the condition of the road surface on a particular > >section of pavement. > > > >It seems to me that a seismograph would be a perfect tool to measure road > >irregularities. However, I am concerned that "standard" seismographs are far > >too sensitive for this type of application? Any ideas? I would appreciate > >your response either good or bad news. > > > >Thanks for your time at this listserv, as you are the folks that know about > >these things. > > > >Jim M. > > > > > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Fausto Grassa" Subject: Re: LARGE QUAKE: RUSSIA Date: Fri, 19 Mar 1999 08:09:13 PST Ciao Francesco, non so come , ma mi arrivano una infinitā di messaggi riguardo un rete si sismografi. Non so come uscirne. Mi puoi aiutare?????????? Grazie!!!!! >From: Francesco >Reply-To: PSN-L Mailing List >To: PSN-L Mailing List >Subject: LARGE QUAKE: RUSSIA >Date: Thu, 25 Feb 1999 22:09:13 +0100 > >Org time: >18:58:34 >Ms 6.1 >Loc.: Lake Baikal Region - Russia > >I.E.SN. PSN ITALY > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L > Get Your Private, Free Email at http://www.hotmail.com _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Francesco" Subject: FOR FAUSTO GRASSA Date: Sun, 21 Mar 1999 18:05:46 +0100 I hand my excuses to all the members of the list for this mail addressed = exclusively to a friend and in Italian language, but I don't know his = direct mail address . Regards Francesco. -------------------- Tu doversti essere iscritto alla mailing list della rete sismica = mondiale PSN. Se vuoi sapere come cancellarti contattami direttamente al mio indirizzo = franuc@......... Piuttosto, tu chi sei? Saluti Francesco
I hand my excuses to all the members = of the list=20 for this mail addressed exclusively to a friend and in Italian language, = but I=20 don't know his direct mail address  . Regards = Francesco.
--------------------
 
Tu doversti essere iscritto alla = mailing list=20 della rete sismica mondiale PSN.
Se vuoi sapere come cancellarti = contattami=20 direttamente al mio indirizzo franuc@......=20
Piuttosto, tu chi sei?
 
Saluti
Francesco
From: Gregory Bajuk Subject: Re: crude seismograph design Date: Fri, 19 Mar 1999 09:20:24 -0800 (PST) Just use one of the AXDL 05 or the new 105 chips On Fri, 19 Mar 1999, Doug Crice wrote: > Most geophones are going to be too sensitive to be used in a moving > vehicle. The moving mass travel is typically 0.1 inch and they will > move enough to hit the stops on any road rough enough for you to want to > measure the vibrations. I vote for the accellerometer, especially since > acceleration is the thing you are interested in for this type of study. > > Phil Schmidt wrote: > > > > At 01:58 AM 3/19/99 -0500, you wrote: > > G'day Jim > > > > Just a thought could you use a accelerometer for this particular > > application since your trailer might be exposed to shocks and suddden > > changes rather than suttle movements. Being a student of the electronics > > trade I have found that several companies on the internet send you, upon > > request free samples of there of some of there products it just so happens > > that Analogue devices do this so you might be able to get a free sample or > > samples of accelerometers off of them. > > > > Just a thought > > > > Cheers Phil Schmidt > > >Hi. > > > > > >I was wondering if anyone could supply me with details, or directions to > > >details, for a homemade yet crude digital seismograph. I would like to > > >monitor the motion of a trailer that will be pulled behind a vehicle. This > > >motion is a result of the condition of the road surface on a particular > > >section of pavement. > > > > > >It seems to me that a seismograph would be a perfect tool to measure road > > >irregularities. However, I am concerned that "standard" seismographs are far > > >too sensitive for this type of application? Any ideas? I would appreciate > > >your response either good or bad news. > > > > > >Thanks for your time at this listserv, as you are the folks that know about > > >these things. > > > > > >Jim M. > > > > > > > > > > > > _____________________________________________________________________ > > 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 From: S-T Morrissey Subject: Re: crude seismograph design Date: Fri, 19 Mar 1999 13:16:05 -0600 (CST) Jim, There is a company here in St. Louis that makes a wide range of seismic sensors, including a 3-component accelerometer package and several digital recorders. at: www.sprengnether.com (314 535 1682) They made all the long period seismometers for the first world-wide array of 200 stations in the '50s. They still make a fine self-contained (including clock and seismic amplifier) portable analogue drum recorder which is used in volcano monitoring and museum displays (the blue boxes you see on the Discovery Channel earthquake/volcano stories). I think that for your application their 24-bit digital recorder can run from battery power in a vehicle. Regarding your question about tiltmeters, the type I have are much too sensitive for surveying, with a maximum range of 100 microradians (0.000057 degree). Even an "inclinometer" might be too sensitive. A wide range of such are made by Geodynamics. (not sure of web addr.) using an electrolytic level sensor from the Philips Glass Co. 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 From: Ted Blank Subject: Re: Lehman pivot point Date: Fri, 19 Mar 1999 17:38:51 -0800 (PST) If you use a single pivot point like a nail, your boom will never stop oscillating around its long axis. Therefore your magnet and coil will have relative motion most of the time. I think this group recommends a design that uses a flexible hinge under tension rather than the knife edge under compression. Ted Blank San Jose, California On Fri, 19 Mar 1999, Phil Schmidt wrote: > G'day All > > I was wondering if anybody could tell me whether it makes any great > difference if the pivot point of a Lehman type seismometer boom is a knife > edge like many of the articles say or a single point like the tip of a nail. > > Cheers Phil Schmidt > > > _____________________________________________________________________ > > 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 From: barry lotz Subject: Re: Lehman pivot point Date: Fri, 19 Mar 1999 18:47:25 -0800 Phil I have been using a knife edge in the past but recently looked at Sean Thomas' web site an I'm convinced that the tension wire top and bottom is better. See his horizontal sketch in the PSN location of his site. S-T Morrissey Barry Phil Schmidt wrote: > G'day All > > I was wondering if anybody could tell me whether it makes any great > difference if the pivot point of a Lehman type seismometer boom is a knife > edge like many of the articles say or a single point like the tip of a nail. > > Cheers Phil Schmidt > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: Re: Lehman pivot point Date: Sat, 20 Mar 1999 00:42:02 -0600 (CST) Phil, Here is a repeat of my note on the subject from last year. It includes the full address to the web site that Barry was referring to: Re. horizontal pivot: I would like to again suggest that a taught flexible hinge or wire be used for the boom pivot of a horizontal seis. Even if a bearing/knife-edge setup has surfaces that are highly polished, say to 1 micro-inch, which is a brightly finished surface, the movement about this surface is still large compared with the ground motions we are trying to record. An irregularity of 1 micro-inch is 25 nanometers, while background earth noise is of the order of 10 nanometers. With the flexible hinge (flexure or taught wire), no surface contacts change as the boom moves, so it is essentially noise free. To avoid any boom rotation problems, an upper taught wire or hinge is used with supporting wires going down to BOTH SIDES of the mass/ coil assembly. It is often described as a "garden gate" suspension. I have posted the drawing of the horizontal seis that has been used since the 50s in the WWNSS (worldwide network of standard seismographs) at http://www.eas.slu.edu/People/STMorrissey/index.html on the page for PSN info. The design is fairly simple and should be easy to implement. Note that the mass is suspended with a forked wire loop from the upper pivot (which is a short taught wire), and is attached to both sides of the upper portion of the mass (NOT the boom), which prevents any rotation. More compact broadband horizontal sensors use miniature flexures of the "Press-Ewing" design, or are actually inverted pendula, where the whole boom with the mass on top rises vertically from a single flexure hinge, which is also clamped to the base vertically. (sort of like a SG built upside down); the hinge flexure controls the period, and its dimensions have to be determined experimentally. Regards, Sean-Thomas _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Charlie Rond Subject: Significant Event Date: Sat, 20 Mar 1999 06:12:04 -0600 Have recorded a significant event 3/20/99 at about 10:55 UTC. Anyone looked at it yet, or know its origins? Charlie Rond -\/\--Public Seismic Network-Memphis http://gandlf.ceri.memphis.edu/~rond/psn _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "David A. Nelson" Subject: Re: Significant Event Date: Sun, 21 Mar 1999 01:22:53 +1300 At 06:12 20/03/99 -0600, you wrote: >Have recorded a significant event 3/20/99 at about 10:55 UTC. > >Anyone looked at it yet, or know its origins? YES !!! Adak Island aleutian islands NO, REPEAT NO, WATCH OR WARNING IS IN EFFECT. AN EARTHQUAKE, PRELIMINARY MAGNITUDE 6.8, OCCURRED AT 0148 AST ON MAR 20, OR 0248 PST ON MAR 20, OR 1048 UTC ON MAR 20. THE EARTHQUAKE WAS LOCATED 50 MILES SW OF ADAK, AK. OR 145 MILES E OF AMCHITKA, AK. AT 51.5N, 177.7W. Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://www.seismicnet.com/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 From: "David A. Nelson" Subject: maj quake Date: Sun, 21 Mar 1999 01:26:31 +1300 USGS listing.... 99/03/20 10:47:45 51.61N 177.73W 33.0 6.8Ms A ANDREANOF ISL, ALEUTIAN IS. Dave Co-ordinator: New Zealand Public Seismic Network Dave A. Nelson ZL4TBN 24 Jensen St., Green Is., Dunedin, South Is.. New Zealand. http://www.seismicnet.com/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 From: browning Subject: Re: crude seismograph design Date: Sat, 20 Mar 1999 08:26:26 -0500 Hello, I can't remember the brand name or manufacture but what your looking for is a package transit monitor. These are self contained vibration sensors/a-to-d converters/memory storage devices made for monitoring freight shipments. They are cheap and easy to download. I think you will be able to find a source through sensor magazine. (my memory thinks they are called hitch-hikers or tag-a-longs or something like that, but I'm only working on about 16k these days) http://www.sensorsmag.com/welcome.htm Lou Browing Jim Morrissey wrote: > > Hi. > > I was wondering if anyone could supply me with details, or directions to > details, for a homemade yet crude digital seismograph. I would like to > monitor the motion of a trailer that will be pulled behind a vehicle. This > motion is a result of the condition of the road surface on a particular > section of pavement. > > It seems to me that a seismograph would be a perfect tool to measure road > irregularities. However, I am concerned that "standard" seismographs are far > too sensitive for this type of application? Any ideas? I would appreciate > your response either good or bad news. > > Thanks for your time at this listserv, as you are the folks that know about > these things. > > Jim M. > > _____________________________________________________________________ > > 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 From: Edward Cranswick Subject: [Fwd: ITALIAN SEISMIC CRISIS] Date: Sat, 20 Mar 1999 17:03:48 -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". Francesco- I apologize for taking so long to reply to this email from you. The email arrived last year the day after (1 April 1998) I went to Australia for three weeks to see my mother. When I returned, there were many email messages and I mislaid some -- including yours -- in the digital confusion. I found your message again after several months but then I kept forgetting to answer. Anyway, two days ago, Paolo Marco De Martini from the Institute in Rome (Istituto Nazionale di Geofisica) gave me a presentation of his work on those events (the first 26 Sep 1997) that you recorded and reported and corresponded with us about then. He gave a lecture here to the Colorado Scientific Society on Tuesday night (9 Mar 1999), "ITALY "TERRAMEMOTUS" COUNTRY: A BIRD'S EYE VIEW ON THE 1997 ASSISI EARTHQUAKES", which I was unable to attend and so he very kindly gave me a personal presentation the next day (and then cooked dinner for several of us at the house at which he was staying in Golden). It was a very interesting lecture he presented (and a good dinner). I rediscovered that Paolo had just returned from field work in Australia in autumn 1997 and your email was some of the first real information he had about the earthquake sequence. Of course, a week after he left here in 1997, we had an earthquake in Alabama which distracted me for the next few months. I am glad that the I.E.S.N. is doing so well. I am sorry that I did not get to see you when you visited Larry Cochrane last year. I wish you well, -Edward Francesco wrote: > Hello Edward,I want to subject your attention this big problem. > The recent seismic crisis that has occourred in Central Italy has > been very anomalous, above all for that that concern the event of > last Thursday. > In September has been audited, like I hope that you know, a big quake, > with two big events to distance of 9 hours: 5.5 mb and then mb 6.0. > The aftershock has lasted around 3 months with many events, (around > 3000) the biggest of which of mb 5.0. The epicenter has been to a > deepth of 9 km. The quake it has been caused from the movement of the > Cesi's Fault, in the Appennines rise , zone of contact among the > African and Euroasiatica plates, zone of high seismicity. > Also if the faults it sleep from about 700 years, I could tell that > the quake reenters in the normal activity of that zone. The stranger > thing but this is. > Last Thursday has been audited an other quake. The epicenter of this > event is completely new and different, 30 km from the precedent one > and in an other zone. In that zone there is an other faults, service > from about 300 years. In the preceding days there has not been no > foreshock, not strumental event . Nothing! Suddenly, a quake [ >5.5 > mb] has been audited and with a depth of 49 km. > From that moment no aftershock has been audited, not strumental event > . Absolutely nothing! > I wait for your response an evaluation. If you want to see the > seismogram or focal mechanism of last event you can see our web site > at http://space.tin.it/scienza/frnucer Thank you. Regards Italian > Expreimentale Seismic NetworkFrancesco Nucera - Osimo, Italy -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". From: Edward Cranswick Subject: Re: PSN message Date: Sat, 20 Mar 1999 17:19:09 -0700 Mike- Thanks for the message. I know Aaron Barzilai. I talked to him at AGU last December when he came by to see my PSN poster, but he really wanted to talk to Sean-Thomas Morrissey about his VBB poster, who unfortunately was unable to attend the meeting. You must be sending email to PSN-L from an address which is not your PSN-L address. You can work that out with Larry Cochrane. -Edward "Stickney, Mike" wrote: > Hello Ed: > I tried to pass this along to the PSN mailing list but apparently am > not allowed to. Would you be so kind as to post it for me . > > Thanks -Mike > > > -----Original Message----- > > From: Stickney, Mike [SMTP:MStickney@.......... > > Sent: Friday, March 19, 1999 4:43 PM > > To: PSN-L@.............. > > Subject: > > > > -------------------------------------------------------------------------- > > MStickney@......... is not allowed to post to the list. > > Please contact root@.............. if you have any problems. > > -------------------------------------------------------------------------- > > > > > > PSN: > > > > Thought this abstract posted with the Seismological Society of > > America for presentation at the May meeting in Seattle may be of interest > > to > > the group. This and other abstracts may be viewed at: > > http://www2.seismosoc.org/abstracts_99/default.html > > > > -Mike Stickney > > Montana Bureau of Mines and Geology > > Butte, MT > > > > ==================================== > > AN AFFORDABLE BROADBAND SEISMOMETER: THE CAPACITIVE GEOPHONE > > BARZILAI, A., Mechanical Engineering, Stanford University, Stanford, CA > > 94305,barzilai@.................... VANZANDT, T., PIKE, T., MANION, S., > > Jet > > Propulsion Laboratory, Pasadena, CA 91109; KENNY, T., Mechanical > > Engineering, Stanford University, Stanford, CA 94305 > > A new style of seismometer has been produced by transforming a geophone > > into > > a broadband seismometer. A conventional geophone has reduced sensitivity > > at > > low frequency, causing poor low frequency performance. This results from > > the > > electrical system of a geophone, which uses the motion of a spring > > supported > > coil in the field of a permanent magnet to generate an output signal. > > Rather > > than use this inductive measurement, with a few simple and inexpensive > > modifications the motion can be measured capacitively. A capacitive > > measurement of coil position yields an output that has constant > > sensitivity > > to ground acceleration at frequencies below the mechanical resonance. The > > device is operated as a closed loop seismometer by applying feedback > > forces > > via the coil magnet interaction. Using this integrated actuator, a > > capacitive geophone can have flat response up to frequencies of 50 Hz or > > beyond. With its large low frequency sensitivity, a capacitive geophone's > > resolution can be roughly 2 orders of magnitude greater than that of a > > conventional geophone, on the order of 10 ng per root Hz. -- 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 From: barry lotz Subject: Re: crude seismograph design Date: Sun, 21 Mar 1999 08:11:44 -0800 Hi After racking my brian I finally found one you may be refering to. It's from Silicon Designs, Inc.( www.silicondesigns.com) They are called "G-Loggers". I think there are several varieties and the have mbytes of storage. I'm not sure on price You might check their website. Barry browning wrote: > Hello, > > I can't remember the brand name or manufacture but what your looking for > is a package transit monitor. These are self contained vibration > sensors/a-to-d converters/memory storage devices made for monitoring > freight shipments. They are cheap and easy to download. I think you > will be able to find a source through sensor magazine. (my memory > thinks they are called hitch-hikers or tag-a-longs or something like > that, but I'm only working on about 16k these days) > > http://www.sensorsmag.com/welcome.htm > > Lou Browing > > Jim Morrissey wrote: > > > > Hi. > > > > I was wondering if anyone could supply me with details, or directions to > > details, for a homemade yet crude digital seismograph. I would like to > > monitor the motion of a trailer that will be pulled behind a vehicle. This > > motion is a result of the condition of the road surface on a particular > > section of pavement. > > > > It seems to me that a seismograph would be a perfect tool to measure road > > irregularities. However, I am concerned that "standard" seismographs are far > > too sensitive for this type of application? Any ideas? I would appreciate > > your response either good or bad news. > > > > Thanks for your time at this listserv, as you are the folks that know about > > these things. > > > > Jim M. > > > > _____________________________________________________________________ > > > > 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 From: "Giovanni Rotta" Subject: LARGE QUKE IN PROGRESS ! Date: Sun, 21 Mar 1999 17:32:50 +0100 Large quake in progress now ! 17:27 UTC Giovanni Rotta Via F. Pizzigoni, 10 33010 Resia (Udine) I Lat. 46.373 N Long. 13.305 E rottag@.......... http://www.geocities.com/~resianet/ingssr.htm _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Conti Claudio" Subject: R: LARGE QUKE IN PROGRESS ! Date: Sun, 21 Mar 1999 17:34:33 +0100 ..........an dove....in progress now?????????????? -----Messaggio originale----- Da: Giovanni Rotta A: PSN Data: domenica 21 marzo 1999 17.32 Oggetto: LARGE QUKE IN PROGRESS ! >Large quake in progress now ! >17:27 UTC > >Giovanni Rotta >Via F. Pizzigoni, 10 >33010 Resia (Udine) I >Lat. 46.373 N Long. 13.305 E >rottag@.......... >http://www.geocities.com/~resianet/ingssr.htm > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Conti Claudio" Subject: R: LARGE QUKE IN PROGRESS ! Date: Sun, 21 Mar 1999 17:34:33 +0100 ..........an dove....in progress now?????????????? -----Messaggio originale----- Da: Giovanni Rotta A: PSN Data: domenica 21 marzo 1999 17.32 Oggetto: LARGE QUKE IN PROGRESS ! >Large quake in progress now ! >17:27 UTC > >Giovanni Rotta >Via F. Pizzigoni, 10 >33010 Resia (Udine) I >Lat. 46.373 N Long. 13.305 E >rottag@.......... >http://www.geocities.com/~resianet/ingssr.htm > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Giovanni Rotta" Subject: QUAKE 16:27 UTC LAKE BAJKAL Date: Sun, 21 Mar 1999 17:36:44 +0100 Quake 16:27 UTC LAKE BAJKAL MORE IN PROGRESS Giovanni Rotta Via F. Pizzigoni, 10 33010 Resia (Udine) I Lat. 46.373 N Long. 13.305 E rottag@.......... http://www.geocities.com/~resianet/ingssr.htm _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Re: crude seismograph design Date: Sun, 21 Mar 1999 16:57:15 -0700 Barry- Wish I had a "brian" like yours for rapid random access; where did you get him? Interesting site that you recollected! -Edward > Subject: > Earthquake-induced strong motions > Date: > Sun, 21 Mar 1999 16:23:23 -0700 > From: > Edward Cranswick > To: > Sales@.................. > > > > > Silicon Designs, Inc.- > Have you considered manufacturing low-cost and mass-market > accelerometer systems to record the strong motions produced by > earthquakes, e.g., something like your Model 3310, G-Logger(TM) Data > Acquisition System, but at least an order of magnitude cheaper? > -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". > > > > barry lotz wrote: > Hi > After racking my brian I finally found one you may be refering to. It's from > Silicon Designs, Inc.( www.silicondesigns.com) They are called "G-Loggers". I > think there are several varieties and the have mbytes of storage. I'm not sure on > price You might check their website. > Barry > > browning wrote: > > > Hello, > > > > I can't remember the brand name or manufacture but what your looking for > > is a package transit monitor. These are self contained vibration > > sensors/a-to-d converters/memory storage devices made for monitoring > > freight shipments. They are cheap and easy to download. I think you > > will be able to find a source through sensor magazine. (my memory > > thinks they are called hitch-hikers or tag-a-longs or something like > > that, but I'm only working on about 16k these days) > > > > http://www.sensorsmag.com/welcome.htm > > > > Lou Browing > > > > Jim Morrissey wrote: > > > > > > Hi. > > > > > > I was wondering if anyone could supply me with details, or directions to > > > details, for a homemade yet crude digital seismograph. I would like to > > > monitor the motion of a trailer that will be pulled behind a vehicle. This > > > motion is a result of the condition of the road surface on a particular > > > section of pavement. > > > > > > It seems to me that a seismograph would be a perfect tool to measure road > > > irregularities. However, I am concerned that "standard" seismographs are far > > > too sensitive for this type of application? Any ideas? I would appreciate > > > your response either good or bad news. > > > > > > Thanks for your time at this listserv, as you are the folks that know about > > > these things. > > > > > > Jim M. > > > > > > _____________________________________________________________________ > > > > > > Public Seismic Network Mailing List (PSN-L) > > > > > > To leave this list email listserver@.............. with the body of the > > > message: leave PSN-L > > > > _____________________________________________________________________ > > Public Seismic Network Mailing List (PSN-L) > > To leave this list email listserver@.............. with the body of the > message: leave PSN-L -- Edward Cranswick Tel: 303-273-8609 US Geological Survey, MS 966 Fax: 303-273-8600 PO Box 25046, Federal Center cranswick@........ Denver, CO 80225-0046 USA E.M. Forster said, "Only connect". _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: George Bush Subject: Article and writeup about feedback control Date: Sun, 21 Mar 1999 16:25:50 -0800 For you who have or are considering active feedback for your seismimeter (like is used on S-T Morrissey's vertical seismometer) and want an introduction to this type of a controller loop and how to adjust it, I just ran across an article in the PTdesign magazine, Feb. 1999 issue, p. 29-31. It is entitled "Twenty minute Tune-up" and is a concise description of the PID (Proportional, Integral, and Derivative) closed-loop motion controllers as used in industrial motion controllers. The article describes the feedback loop and how to adjust the three feedback elements (PID), and even offers a simulator program so you can vary the parameters yourself and see the effects on the system. Check out their website http://www.ptdesign.com for information on the magazine (free to qualified subscribers), and how to download the software. George Bush Sea Ranch, CA, USA 38.74N, 123.5W _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: pouellette Subject: Re: GPS and DSL Date: Wed, 17 Mar 1999 11:08:59 -0500 For a lower-cost antenna, see my website: http://www.sawcenter.com/gpsant.htm ..Its an active antenna with your choice of connectors starting at $19.95 ea. Peter Larry Cochrane wrote: > All, > > Recently I ran into the following "good deals". > > GPS Timing Receivers. > > In the process of getting a GPS timing receiver for one of our PSN station > I found out that Motorola has reduced the cost of the GPS receiver > compatible with SDR. Last year the GPS receiver I used to develop the code > to cost $199.00. It now costs $171.00 in small numbers. The active antenna > is still around $50.00. I bought the receiver and antenna at Synergy > Systems (www.synergy-gps.com). For more information on GPS and SDR see the > web page at http://www.seismicnet.com/sdrdocs/gps.htm. > > DSL Internet Connection. > > If you surf the web a lot and live in an area serviced by PacBell you might > check into seeing if you can get a DSL connection into the Internet. For > less then $50.00 a month one can get literally T1 (a high speed link > normally used by businesses and costing over $1K per month) download speeds! > > In December of last year I moved my Internet connection over to DSL with a > 384 k bit incoming / 128 k bit outgoing connection with 5 IP address. The > cost was going to be ~137.00 per month, only a little over the $105.00 per > month I was paying for a 28k bit (in and out going) connection. The > increase in bandwidth was great. > > In late Jan. or early Feb. PacBell announced new pricing for their DSL > services. For ~$80.00 a month (~50.00 for a single IP address, I have 5 IP > numbers so the cost is a little higher) I could get my service changed and > get 384 + / 128 bit connection. The + means they would increase the > incoming bandwidth to 1+ meg bit rate, if my line connection can handle it. > There is a ~3 mile limit on the distance DSL will work using the standard > phone line wires between the you and the central office. The farther away, > the less bandwidth you can get. If I remember right I'm about 2 miles from > the central office. > > Since it looked I was getting more for less I called PacBell and changed my > service. It took several more calls to PacBell to get them to remove the > bandwidth limitation on my connection. Last Friday they finally called me > to let me know that the bandwidth should be higher, if my the connection > can handle it. I have access to several systems with very good connectivity > on the Internet. After doing some download tests using FTP on large files I > determined I was getting download speeds peaking at 1.2 meg bit (~152 meg > byte per sec.) download speeds. I can now download a 30 meg byte file in > about 3 minutes. With my old 28.8k connection it would take over 2 hours to > download the same file. > > With DSL you can also setup your own Web and FTP servers since you get a > static IP address assigned too you. > > As they say on the Internet, I don't work for Synergy Systems or PacBell.... > > -Larry Cochrane > Redwood City > > _____________________________________________________________________ > > 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 From: Larry Cochrane Subject: Re: GPS Antenna Date: Sun, 21 Mar 1999 22:30:21 -0800 Peter, Thanks for the information, I'll add a link to your web page. Can you supply the RA/OSX RF connector used on the ONCORE unit? I don't see it listed on your web page. Also, can the unit be mounted outside? -Larry Cochrane Redwood City, PSN At 11:08 AM 3/17/99 -0500, you wrote: >For a lower-cost antenna, see my website: http://www.sawcenter.com/gpsant.htm >.Its an active antenna with your choice of connectors starting at $19.95 ea. >Peter _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: crude seismograph design Date: Mon, 22 Mar 1999 17:27:13 -0800 Hi Ed I'm "Brian" dead sometimes. I got it from Sensors magazine; an interesting, but primarily a sensor product add magazine. Barry Edward Cranswick wrote: > Barry- > Wish I had a "brian" like yours for rapid random access; where did you get him? > Interesting site that you recollected! > -Edward > > > Subject: > > Earthquake-induced strong motions > > Date: > > Sun, 21 Mar 1999 16:23:23 -0700 > > From: > > Edward Cranswick > > To: > > Sales@.................. > > > > > > > > > > Silicon Designs, Inc.- > > Have you considered manufacturing low-cost and mass-market > > accelerometer systems to record the strong motions produced by > > earthquakes, e.g., something like your Model 3310, G-Logger(TM) Data > > Acquisition System, but at least an order of magnitude cheaper? > > -Edward > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Earthquakes can cause frictional melting of plates... Date: Mon, 22 Mar 1999 19:58:40 -0800 All, While surfing the Net I ran across this interesting article: "Energy of some earthquakes can cause frictional melting of plates, geophysicists find" at http://www.caltech.edu/~media/lead/020598QUAKE.html. Interesting stuff... Regards, Larry Cochrane Redwood City, PSN _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: The Lahrs Subject: Re: Lehman pivot point Date: Mon, 22 Mar 1999 20:57:43 -0700 >I am attempting, with the help of two friends, to build a Lehman-style >horizontal seismometer. I'm using the suspension system of >the WWNSS seismometers, as Sean-Thomas recommends. I've started, >and will continue, to describe progress on this web site: > >http://lahr.org/john-jan/psn/psn.html > >I have some preliminary drawings of the system posted at this time. >What is the recommended composition of the taught wires used in the >suspension? > >I plan on using the coil and magnet from a 12" speaker. I know there has >been discussion of this, but will this work? Or should I wind a coil >with a greater number of turns? The current coil has a resistance of >4 ohms (according to the speaker label). > >I widened the gap, which was no easy task. The back plate (B) and center >slug (CS) were ONE CAST UNIT, so of cource all of my efforts to break >the center slug loose were for naught. I also boiled the whole >magnet, but the glue would not loosen between the back plate(B) or >the front plate (F) and the ceramic dougnut magnet (nnss). In the >end I cutl the center slug (CS) free on the lathe. > >After I had widened the gap, the next challenge was getting the center >slug (CS) centered again. The magnet is so strong that I had to use a >wood clamp and wedges to force the center slug away from the edge of >the front plate (F). > > > BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB > nnnnnnnnn CSCSCS nnnnnnnnn > nnnnnnnnn CSCSCS nnnnnnnnn > sssssssss CSCSCS sssssssss > sssssssss CSCSCS sssssssss > FFFFFFFFFFFF CSCSCS FFFFFFFFFFFF > >Cheers, >John * John C. and Jan H. Lahr * * JohnJan@........ * * 1925 Foothills Road * * Golden, Colorado 80401-1718 * * (303) 215-9913 * * http://lahr.org/john-jan * * AOL version of homepage: * * http://lahr.org/john-jan/homepage.html * * http://giseis.alaska.edu/lahr * _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Charles R. Patton" Subject: Re: hinges,flexures, contd Date: Mon, 22 Mar 1999 19:49:43 -0800 Sean-Thomas, Thanks for the historical results of actual use of Rolomite bearings in a seismometer. When playing with models from =BC to 2 inch diameter, they seem perfect in comparison to real ball bearings. I do have one question that has been nagging me though about the use of flexure hinges. It seems to be taken for granted that the simple, non-Bendix flexures have a constant center of rotation. That absolutely doesn=92t happen. The radius shortens up with increasing displacement due to the non-uniform curvature taken by the spring/hinge. This is easy to see by taking a strip of just about anything that is =93springy=94 such as plast= ic strapping tape, steel bands, spring wire, etc. Clamp it and then push the tip while marking the tip position on a piece of paper below. There is significant deviation from a constant radius. Maybe Brett could model that too. Since the deflections of a seismometer are so small, perhaps this doesn=92t enter into the calculations, but if the Rolamite non-smoothness affects a seismometer that drastically, maybe this becomes part of the equation. Regards, Chas. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Edward Cranswick Subject: Re: Lehman pivot point Date: Mon, 22 Mar 1999 22:31:03 -0700 John- Well I am glad to see that someone is upholding the honor of the USGS as a truly participating member of the PSN! -Edward The Lahrs wrote: > >I am attempting, with the help of two friends, to build a Lehman-style > >horizontal seismometer. I'm using the suspension system of > >the WWNSS seismometers, as Sean-Thomas recommends. I've started, > >and will continue, to describe progress on this web site: > > > >http://lahr.org/john-jan/psn/psn.html > > > >I have some preliminary drawings of the system posted at this time. > >What is the recommended composition of the taught wires used in the > >suspension? > > > >I plan on using the coil and magnet from a 12" speaker. I know there has > >been discussion of this, but will this work? Or should I wind a coil > >with a greater number of turns? The current coil has a resistance of > >4 ohms (according to the speaker label). > > > >I widened the gap, which was no easy task. The back plate (B) and center > >slug (CS) were ONE CAST UNIT, so of cource all of my efforts to break > >the center slug loose were for naught. I also boiled the whole > >magnet, but the glue would not loosen between the back plate(B) or > >the front plate (F) and the ceramic dougnut magnet (nnss). In the > >end I cutl the center slug (CS) free on the lathe. > > > >After I had widened the gap, the next challenge was getting the center > >slug (CS) centered again. The magnet is so strong that I had to use a > >wood clamp and wedges to force the center slug away from the edge of > >the front plate (F). > > > > > > BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB > > nnnnnnnnn CSCSCS nnnnnnnnn > > nnnnnnnnn CSCSCS nnnnnnnnn > > sssssssss CSCSCS sssssssss > > sssssssss CSCSCS sssssssss > > FFFFFFFFFFFF CSCSCS FFFFFFFFFFFF > > > >Cheers, > >John > > * John C. and Jan H. Lahr * > * JohnJan@........ * > * 1925 Foothills Road * > * Golden, Colorado 80401-1718 * > * (303) 215-9913 * > * http://lahr.org/john-jan * > * AOL version of homepage: * > * http://lahr.org/john-jan/homepage.html * > * http://giseis.alaska.edu/lahr * > > _____________________________________________________________________ > > 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 From: S-T Morrissey Subject: Re: hinges,flexures, contd Date: Tue, 23 Mar 1999 01:43:52 -0600 (CST) Charles, Please don't imply that I ever said a seismometer used a rolamite bearing; they are simply too noisy because of the contact surface. The large 1-second Johnson-Matheson uses a single-element crossed-flexure hinge called a "cardan" hinge, which has no contact between the supporting cylinders. Regarding the center of rotation of hinges: The flat flexures used in seismometers are always used in orthogonal pairs, which absolutely does constrain the center of rotation to a fixed axis within the thickness of the hinge material. This allows for tight tolerances in the coil/magnet alignment. Any residual change in the point of rotation, as along the axis of the boom, only has the effect of moving the coil parallel to the magnet face, which produces no output. Where a taught wire suspension is used, as in large horizontals like John L. is working on, the flexing portion is always much much shorter and much more flexible than the rest of the boom length or the length of the upper yoke, so a change on the point of flexure is minimized. In fact, such a change would not produce or modify the output noise of the seismometer; it just increases the tolerances needed in the alignment requirements for the coil in the magnet, etc. For large seismometers, dimensional changes from temperature and aging stress are significantly larger. In the case of etched leaf suspensions as in large and small geophones, the coil/mass actually rotates as it moves up and down in the magnet, but the coil rotation does not produce any output signal. 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 From: Karl Cunningham Subject: Leaf Spring Temperature Tests Date: Tue, 23 Mar 1999 00:13:21 -0800 Hi to all Leaf Spring fans -- With all the recent talk about using leaf springs I thought I'd use one, but I wasn't sure about the temperature coefficient of force. Then, Brett Nordgren did a great job of calculating temperature coefficient. I still wanted to try measuring the Temperature Coefficient of a leaf spring to see how it compared. I recently did so and found it to be -235ppm/deg C, a pretty good match compared to Brett Nordgren's calculations, even though the geometry is slightly different. If anyone is interested, I've written up the details. See http://www.jps.net/karlc/fbtests.pdf . I'm interested in anyone's comments. Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Warner Subject: Please, These Wires Are Not Dumb Date: Tue, 23 Mar 1999 05:05:55 -0800 (PST) They're tightly stretched. Wouldn't they be TAUT wires? --Warner Puget Sound Country _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: Re: hinges,flexures, contd Date: Tue, 23 Mar 1999 08:46:24 -0500 Charles, I agree with Sean-Thomas that the Rolamite just won't do the job. Regarding the single flexure spring, indeed it does not generate a perfect circle, the amount of error depending on its thickness and length relative to its tension. An accurate analysis, avoiding all the usual approximations is a bit of work. On the other hand, such hinges normally are required to bend only a small fraction of a degree, and I'd bet that the arc you got at the end of the boom, over a small range, would match a circle very well, even with a fairly stiff spring. Actually, I'm not even sure why one wants the boom-end to follow a circle. It would seem that a straight line (or extremely large radius arc) might be the best of all. Possibly a bigger disadvantage of this design is the effect of its stiffness on a very long period set up. The crossed-flexure arrangement is, in theory, by far the best performing arrangement that I've come across. I'd made such a botch of my first analysis of a variation of that design (unfortunately still on my Web page) that I've been doing a lot of work to get it right this time. The results are a still a bit tentative, but what I've been finding is that, although the center of rotation does move around a modest amount as the hinge is flexed (over say +/- 5 deg) that does *not* translate into a correspondly large error in the arc described by the end of the boom. In fact, set up properly the boom-end traces an almost perfect circular arc. That sounds a bit contradictory, but now I'm working to understand what's happening well enough to be able to explain it in a way that makes sense. Regards, Brett _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Lahr Subject: Re: Please, These Wires Are Not Dumb Date: Tue, 23 Mar 1999 08:37:38 -0700 (MST) Warner, Good point! I need a "context" checker along with my spelling checker. JCLahr > Date: Tue, 23 Mar 1999 05:05:55 -0800 (PST) > From: Warner > > They're tightly stretched. Wouldn't they be TAUT wires? > --Warner _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Karl Cunningham (by way of Karl Cunningham ) Subject: Re: Leaf Spring Temperature Tests Date: Tue, 23 Mar 1999 07:52:34 -0800 Oooops -- the url for the leaf spring testing should have been: http://www.jps.net/karlc/lstests.pdf . Karl Cunningham La Mesa, CA. PSN Station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Karl Cunningham Subject: Re: hinges,flexures, contd Date: Tue, 23 Mar 1999 08:16:24 -0800 Brett -- At 08:46 AM 3/23/99 -0500, you wrote: >Possibly a bigger disadvantage of this design is the effect of its >stiffness on a very long period set up. I'm not sure this is even much of a problem, so long as the flexure's curve of force vs. deflection is similar to that of the restoring force (due to gravity) vs. deflection. These two forces add, but the restoring force is adjustable by adjusting the direction of a vector from upper to lower centers of rotation with respect to the gravity vector (by tilting the instrument forward or back). And if the upper center of rotation is behind the lower, the restoring force is negative and will reduce the effect of the force of the flexure. So long as the curves are similar (and I think they are a pretty good match for small deflections), long periods are still possible with reasonably stiff flexures. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: Re: Leaf Spring Temperature Tests Date: Tue, 23 Mar 1999 12:56:18 -0500 Karl: Beautiful measurement! I'd been hoping to get some kind of confirmation that the calculation was reasonable. If I understand it, you're seeing a value about 20% higher than my numbers were predicting, though for this kind of effect, that's practically dead-on. I'm curious that your total number (-235ppm/deg) is so close to my assumed value for the T.C. of the Elastic modulus alone, (-240ppm/deg). It's undoubtedly just a coincidence, but it caught my attention. My best guess for the difference, is that the true T.C. for E differs from -240. I've never actually seen the results of measurements (until now) that would justify a particular value, just statements that -240 was the value to use. According to Streckeisen (I think), the T.C. is itself a significant function of temperature, which may also relate to the difference between your measurements and the value that I've been assuming. Would there be any easy way to use your test setup to get a room temp. force-length plot for your spring? That's another calculation that I'd feel happier about if there were some better data to back it up. I'm starting now to also look at the equations for fixed-end springs. Such a design would probably be a little easier to build, but there are more degrees of freedom; which cuts both ways. You might be able to match the boom geometry even better, to extend the free period, but, there would also be more interacting adjustments to get right. My idea is to get close enough with the calculations so that I could limit the final adjustments to minor tweaking. That very much remains to be seen. Really enjoyed seeing the elegant work you've done. Regards, Brett _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Karl Cunningham Subject: Re: Leaf Spring Temperature Tests Date: Tue, 23 Mar 1999 12:11:15 -0800 Hi Brett -- Thanks for the comments. I'm sure -235ppm/deg being so close to -240ppm/deg is mostly coincidence, and I too was surprised at how close my measurements matched your calculations. When measurement appears to confirm theory, it gives us confidence in both. Hopefully one isn't lying and the other swearing by it! You wrote: >Would there be any easy way to use your test setup to get a room temp. >force-length plot for your spring? That's another calculation that I'd >feel happier about if there were some better data to back it up. That would be a very interesting test. I'll work on that. One way to do it would be to attach a dial indicator to measure leaf spring deflection, and have some sort of length adjustment in the tension wire -- maybe adapt the worm drive mechanism of a guitar tuner. With my leaf spring arrangement, the range of deflection of the spring is only a few millimeters (5:1 more at the end of the reaction arm), so it wouldn't test over much of a range. And it won't simulate the effects of boom geometry of Sean-Thomas's instrument. But I'll give it a try anyway. -- Karl _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: pouellette Subject: Re: GPS Antenna Date: Tue, 23 Mar 1999 14:23:41 -0500 Sorry, I'm not familiar with that connector, however I have a friend who just got a oncore eval kit and I will check with him..The antenna is not waterproof but can be inserted into a empty cd case & filled with silicon or epoxy to weatherproof. Peter Larry Cochrane wrote: > Peter, > > Thanks for the information, I'll add a link to your web page. Can you > supply the RA/OSX RF connector used on the ONCORE unit? I don't see it > listed on your web page. Also, can the unit be mounted outside? > > -Larry Cochrane > Redwood City, PSN > > > At 11:08 AM 3/17/99 -0500, you wrote: > >For a lower-cost antenna, see my website: http://www.sawcenter.com/gpsant.htm > >.Its an active antenna with your choice of connectors starting at $19.95 ea. > >Peter > > _____________________________________________________________________ > > 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 From: John Hernlund Subject: Re: Melting Plates Date: Tue, 23 Mar 1999 18:39:56 -0700 (MST) Larry, Yes, this is quite an interesting earthquake (the large Bolivian event a few years back). There was an issue of "Geophysical Research Letters" some time ago that contained a large series of articles about this quake. Another interesting thing about this quake is that it had a horizontal fault plane, imagine that! This was quite a large event in a portion of the bend in the Nazca slab (under and to the west of the coastal bend in South America) at around 660 km depth, where geochemists believe the minerals of both the upper mantle and the sinking slab transform into denser phases called pervoskite, ilmenite, magnesiowustite, and maybe even some garnet. Proponents of a 2-layer convection model in the earth believe that the physical properties across the boundary change by extraordinary degrees. Many people are offering many ideas about how this earthquake worked, but there are no sure answers. Some of them are a little too far out, even coming from good scientists. I am working on another idea, but I am not sure if somebody else has already "thunk" it. I kind of think it is a fundamental part of being at a bend that may allow these things. Just like you can shove things harder with a folded peice of paper, you can shove this bent peice down harder into this 660 km layer than if it were just an unbent flap. Try this on your own if you never have done it before. Like try pushing a coffee cup across a table without doubling up the paper. If you bend the paper into an S-shape (as viewed looking at the cup) then you can push the cup even if the paper is very flimsy. Now try pushing the cup without bending, and you will see that it is impossible... But this idea requires looking at things in 3-D, a method still lacking in most geophysical sciences... ****************************************************************************** John Hernlund E-mail: 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 From: S-T Morrissey Subject: Lehman suspension, coils Date: Tue, 23 Mar 1999 21:00:02 -0600 (CST) John, On the drawing of the Long Period horizontal that I posted I have noted the size of the suspension wires in standard gauges, which is neither practical nor learned (as in taught!). These wires are high tensile steel as in piano wires, which can be be purchased for $5 to $10 per pound (a pound of #22 steel wire is about 150 feet) from suppliers like McMaster-Carr . However, standard guitar wires are affordable and are the same material. I dug up a spare set for my old D-12 for this information: the #30 wire size is 0.010", and is not a "guitar" size so use a slightly larger size: the #28 wire is 0.012, and is an E or first string the #26 wire is 0.0159, and is a B or second string the #22 wire is 0.0253, and is a G or third string There is nothing special about these sizes; the smaller sizes are used for the pivot wires, and the larger size supports the boom/mass from the upper yoke. The main point is that they should not stretch appreciably. A minor benefit of guitar wires is that they are chrome plated and will not rust. Also, the small brass ring fitted to the box end could be used in the seismometer installation. Regarding the magnet: the 10" speaker that I use has a 5/16" hole through the pole of the magnet. Rather than attempting to dismantle the magnet, which is riveted together, I experimented with enlarging the gap using a 1/8" solid carbide drill (for cutting tile with a router) and a small drill press. It does work, but allow yourself the duration of a TV movie you have already seen to fish the steel filings out of the gap one tweezer-full at a time, then with masking tape. I concluded that I would continue to use the magnet with the original gap; if a speaker coil can stay aligned for years, so can the seismometer. Regarding the coil: the output, or generator constant, increases with the square of the resistance, assuming the same volume of winding is used. This means that if you wind a 400 ohm coil to replace the 4 ohm original, you will get 10 times the output. This gain can also be realized with a properly selected preamplifier, like the OP27. A problem with winding a new coil is finding a suitable form material that fits the magnet geometry. You want as thin a cylinder as possible, so that your hard-won magnet gap is mostly filled with moving coil, not moving plastic. (A metal form will act as a one-turn coil and seriously damp the movement). If you use the original form, here are some numbers: Assume that the original 4-ohm coil is 1.5" diameter and wound with #28 copper wire at 15.4 ohms/ft. This makes the winding 61.64 feet long. Divided by the mean length/turn 0.393ft, it has 156 turns (in our assumption). For 10x output, the resistance is 100x, or 400 ohms. For a given coil form, the wire size scales by the 4th root of the resistance. So the 4th root of 100 is 0.316, multiplied by the size of the #28 wire, 0.316 x 0.01264 = 0.00399, which is about the size of #38 wire. THis #38 has 1.52 ohms/foot, so 400 ohms is 606 ft, wound at a mean diameter of 1.5" (= 0.393ft/turn) results in 1544 turns. Which is about 10x the original number of turns, as we would expect, but we now know the wire size. For 50 times the output, the ratio is 2500x, requiring a 10 000 ohm coil. This works out to about 3040 ft of #45 wire, wound in 7735 turns. I would go for the 10x coil, and use more amplifier gain rather than winding this last option. Another problem with using the original low resistance coil as a basic velocity sensor is damping it with a suitable low-value resistor. (This is not a problem when feedback is used, since the damping is non-dissipative via the proportional resistor). If you do wind a new coil, try to keep track of the number of turns and the total length of the wire used (the resistance divided by the ohms/foot), since these can help confirm any later determination of the generator constant. I have used a manual hand drill clamped to the table to support the coil for winding the auxillary coils for calibration and thermal compensation. I suppose that a very low speed electric drill could be used with a router AC foot switch for a multi-turn, multi-layer winding. I would not "scramble wind", since this wastes coil space and any tension can force the windings into themselves which expands the winding and breaks the form. I am curious about what you are considering using for the main base plate. Of primary concern for a horizontal seismometer is a suitably rigid base plate. There has been some discussion of surplus finds of such. Purchasing can be expensive: McMaster has 12" x 24" x 1/2" hard-tempered aluminum plate for about $100 (1/4" for $50). The large thermal inertia and conductivity of aluminum is important, (as is the use of 80 thread/inch leveling screws.) For my prototype VBB horizontals, I made a composite inverted channel with 1/8" and 1/4" aluminum angles and bar stock epoxied and bolted together, but I am not satisfied with the result. A monolythic plate would be better. And the size needs to be considered in respect to whatever cover might eventually be used. 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 From: S-T Morrissey Subject: Lehman suspension, coils Date: Tue, 23 Mar 1999 21:00:02 -0600 (CST) John, On the drawing of the Long Period horizontal that I posted I have noted the size of the suspension wires in standard gauges, which is neither practical nor learned (as in taught!). These wires are high tensile steel as in piano wires, which can be be purchased for $5 to $10 per pound (a pound of #22 steel wire is about 150 feet) from suppliers like McMaster-Carr . However, standard guitar wires are affordable and are the same material. I dug up a spare set for my old D-12 for this information: the #30 wire size is 0.010", and is not a "guitar" size so use a slightly larger size: the #28 wire is 0.012, and is an E or first string the #26 wire is 0.0159, and is a B or second string the #22 wire is 0.0253, and is a G or third string There is nothing special about these sizes; the smaller sizes are used for the pivot wires, and the larger size supports the boom/mass from the upper yoke. The main point is that they should not stretch appreciably. A minor benefit of guitar wires is that they are chrome plated and will not rust. Also, the small brass ring fitted to the box end could be used in the seismometer installation. Regarding the magnet: the 10" speaker that I use has a 5/16" hole through the pole of the magnet. Rather than attempting to dismantle the magnet, which is riveted together, I experimented with enlarging the gap using a 1/8" solid carbide drill (for cutting tile with a router) and a small drill press. It does work, but allow yourself the duration of a TV movie you have already seen to fish the steel filings out of the gap one tweezer-full at a time, then with masking tape. I concluded that I would continue to use the magnet with the original gap; if a speaker coil can stay aligned for years, so can the seismometer. Regarding the coil: the output, or generator constant, increases with the square of the resistance, assuming the same volume of winding is used. This means that if you wind a 400 ohm coil to replace the 4 ohm original, you will get 10 times the output. This gain can also be realized with a properly selected preamplifier, like the OP27. A problem with winding a new coil is finding a suitable form material that fits the magnet geometry. You want as thin a cylinder as possible, so that your hard-won magnet gap is mostly filled with moving coil, not moving plastic. (A metal form will act as a one-turn coil and seriously damp the movement). If you use the original form, here are some numbers: Assume that the original 4-ohm coil is 1.5" diameter and wound with #28 copper wire at 15.4 ohms/ft. This makes the winding 61.64 feet long. Divided by the mean length/turn 0.393ft, it has 156 turns (in our assumption). For 10x output, the resistance is 100x, or 400 ohms. For a given coil form, the wire size scales by the 4th root of the resistance. So the 4th root of 100 is 0.316, multiplied by the size of the #28 wire, 0.316 x 0.01264 = 0.00399, which is about the size of #38 wire. THis #38 has 1.52 ohms/foot, so 400 ohms is 606 ft, wound at a mean diameter of 1.5" (= 0.393ft/turn) results in 1544 turns. Which is about 10x the original number of turns, as we would expect, but we now know the wire size. For 50 times the output, the ratio is 2500x, requiring a 10 000 ohm coil. This works out to about 3040 ft of #45 wire, wound in 7735 turns. I would go for the 10x coil, and use more amplifier gain rather than winding this last option. Another problem with using the original low resistance coil as a basic velocity sensor is damping it with a suitable low-value resistor. (This is not a problem when feedback is used, since the damping is non-dissipative via the proportional resistor). If you do wind a new coil, try to keep track of the number of turns and the total length of the wire used (the resistance divided by the ohms/foot), since these can help confirm any later determination of the generator constant. I have used a manual hand drill clamped to the table to support the coil for winding the auxillary coils for calibration and thermal compensation. I suppose that a very low speed electric drill could be used with a router AC foot switch for a multi-turn, multi-layer winding. I would not "scramble wind", since this wastes coil space and any tension can force the windings into themselves which expands the winding and breaks the form. I am curious about what you are considering using for the main base plate. Of primary concern for a horizontal seismometer is a suitably rigid base plate. There has been some discussion of surplus finds of such. Purchasing can be expensive: McMaster has 12" x 24" x 1/2" hard-tempered aluminum plate for about $100 (1/4" for $50). The large thermal inertia and conductivity of aluminum is important, (as is the use of 80 thread/inch leveling screws.) For my prototype VBB horizontals, I made a composite inverted channel with 1/8" and 1/4" aluminum angles and bar stock epoxied and bolted together, but I am not satisfied with the result. A monolythic plate would be better. And the size needs to be considered in respect to whatever cover might eventually be used. 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 From: "Al Allworth" Subject: Inclinometer Date: Tue, 23 Mar 1999 22:18:38 -0800 Hi All, What would a Terrascience inclinometer be used for? (Model TPC-110) I suppose this might be interesting for Volcanic work. I saw one on a sale list. ____________________________________ Al Allworth allworth@.............. Gold Beach On The Beautiful Southern Oregon Coast ____________________________________ ----- Original Message ----- From: Larry Cochrane To: PSN-L Mailing List Sent: Sunday, March 21, 1999 10:30 PM Subject: Re: GPS Antenna > Peter, > > Thanks for the information, I'll add a link to your web page. Can you > supply the RA/OSX RF connector used on the ONCORE unit? I don't see it > listed on your web page. Also, can the unit be mounted outside? > > -Larry Cochrane > Redwood City, PSN > > > At 11:08 AM 3/17/99 -0500, you wrote: > >For a lower-cost antenna, see my website: http://www.sawcenter.com/gpsant.htm > >.Its an active antenna with your choice of connectors starting at $19.95 ea. > >Peter > > > _____________________________________________________________________ > > 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 From: shansen@........ (shansen) Subject: More Surplus Geophones Date: Wed, 24 Mar 1999 05:58:43 -0500 (EST) American Science and Surplus' most recent catalog lists a Geosource MD-100 geophone. The 14 Hz freq is a bit high but it might be of value to someone. Catalog number is 29593 with a price of $15. They can be reached at 847-982-0870. Steve Hansen _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Doug Crice Subject: Re: Inclinometer Date: Wed, 24 Mar 1999 08:43:56 -0800 Al Allworth wrote: > > Hi All, > > What would a Terrascience inclinometer be used for? > (Model TPC-110) > I suppose this might be interesting for Volcanic work. > > I saw one on a sale list. > ____________________________________ > I believe that these are sensitive electronic tiltmeters. They are normally used to monitor things like active landslides, dams, and structures. I'm not sure of the sensitivity of this particular model, but tiltmeters are routinely used to monitor volcanos--it seems they swell up before they erupt which tilts the sides. _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: Melting Plates Date: Wed, 24 Mar 1999 10:39:26 -0700 (MST) If anyone is interested in learning more about that earthquake the issue of Geophysical Research Letters I mentioned previously is Vol. 22, No. 16, Pages 2231-2324, Aug. 15, 1995. There is almost 100 pages on this issue, and I did find at least one paper in this issue (Kirby and others 2233-2236) that mentions kinking as helping to resist slab bending... ****************************************************************************** John Hernlund E-mail: 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 From: Ted Blank Subject: Re: Guitar suspensions Date: Wed, 24 Mar 1999 11:31:42 -0800 (PST) I am waiting for Sean-Thomas to present us with the design that plays the music of the country in which the quake occured on the guitar strings. Let's see, with three units at orthogonal orientations, each tuned in a different key...it's too quiet in those vaults anyway. :-) Ted Blank San Jose, California _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: barry lotz Subject: Re: Lehman pivot point Date: Wed, 24 Mar 1999 13:25:26 -0800 Hi John $0.02--- speaker magnet ramblings-- I first filed/drilled the gap larger but used much 50 mph tape in the process, to clean out the filings. I found that soaking the magnet in carburator cleaner(mythel chloride-spelling?) worked better. Each speaker magnet seemed to take different soaking times. I then 5 min. epoxied the steel donut part of the speaker magnet to the magnet. After it set I found a flexible/circular piece of material for use as a spacer and inserted the core portion thru the donut portion, after applying some epoxy. The spacer kept the core centered til the epoxy set. I used a split piece of copper pipe. Regards Barry The Lahrs wrote: > >I am attempting, with the help of two friends, to build a Lehman-style > >horizontal seismometer. I'm using the suspension system of > >the WWNSS seismometers, as Sean-Thomas recommends. I've started, > >and will continue, to describe progress on this web site: > > > >http://lahr.org/john-jan/psn/psn.html > > > >I have some preliminary drawings of the system posted at this time. > >What is the recommended composition of the taught wires used in the > >suspension? > > > >I plan on using the coil and magnet from a 12" speaker. I know there has > >been discussion of this, but will this work? Or should I wind a coil > >with a greater number of turns? The current coil has a resistance of > >4 ohms (according to the speaker label). > > > >I widened the gap, which was no easy task. The back plate (B) and center > >slug (CS) were ONE CAST UNIT, so of cource all of my efforts to break > >the center slug loose were for naught. I also boiled the whole > >magnet, but the glue would not loosen between the back plate(B) or > >the front plate (F) and the ceramic dougnut magnet (nnss). In the > >end I cutl the center slug (CS) free on the lathe. > > > >After I had widened the gap, the next challenge was getting the center > >slug (CS) centered again. The magnet is so strong that I had to use a > >wood clamp and wedges to force the center slug away from the edge of > >the front plate (F). > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Lahr Subject: Re: Lehman pivot point Date: Wed, 24 Mar 1999 14:55:40 -0700 (MST) Sean-Thoman and Barry, Thanks for the further tips and advice. I just purchased an E guitar string (.012) for some new taut-wire hinges, and for two wires that attach to the mass. If I ever decide to take a speaker magnet apart again, I'll try the carburator cleaner first! The next challenge will be the amplifier. I believe in an iterative approach. So this first horizontal may be limited to nearby magnitude 7 earthquakes, but the second one I build ... JCLahr _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: Hinges - - again Date: Wed, 24 Mar 1999 21:13:06 -0500 To all: Think I may have have it right this time. file: zerohng2.pdf at: http://members.home.net/nordgren/public/ Analysis of "zero force" crossed flexure spring design. Brett _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Wayne Abraham J73WA Subject: Telemetry Decoder Date: Thu, 25 Mar 1999 18:12:16 -0400 PSN Does anyone on this list have one of Larry's telemetry decoder boards they would not mind parting with? I am interested in purchasing one for monitoring a station close to my home. Please reply directly to my email address. Thanks, Wayne -- Wayne Abraham 1430 Rodney Street Portsmouth, Dominica abrahamw@........ http://www.freeyellow.com/members6/dominicapsn/ _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: e-book on Seismic Waves Date: Thu, 25 Mar 1999 20:56:19 -0500 To all, Just ran across the online book "Seismic wave propagation modeling and inversion" Bit over my head, but maybe it would be of interest to someone here. Apologies if this is already common knowledge. http://csep1.phy.ornl.gov/sw/sw.html Brett _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Bonnie Schafer" Subject: Re: e-book on Seismic Waves Date: Thu, 25 Mar 1999 20:39:03 -0800 Hi, thank you so much for posting this. I suspect I won't understand all of this book but am always looking for books that I can read online since some of them are hard to scan. Thank you so much. 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 From: GeE777@....... Subject: Re: e-book on Seismic Waves Date: Fri, 26 Mar 1999 11:13:58 EST In a message dated 3/25/99 5:56:04 PM Pacific Standard Time, bnordgren@.............. writes: << To all, Just ran across the online book "Seismic wave propagation modeling and inversion" Bit over my head, but maybe it would be of interest to someone here. Apologies if this is already common knowledge. http://csep1.phy.ornl.gov/sw/sw.html Brett >> Hello This e-book deals with seismic exploration. It probably won't help much in understanding natural seismic events. George Erich Seismic Exploration Consultant P. O. Box 2011, Norwalk, CA 90651, U. S. A. Phone (562) 868-6013 e-mail GeE777@....... 33 53.90N 118 04.53W _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: e-book on Seismic Waves Date: Fri, 26 Mar 1999 11:01:44 -0700 (MST) On Fri, 26 Mar 1999 GeE777@....... wrote: > This e-book deals with seismic exploration. It probably won't help much in > understanding natural seismic events. > George Erich George, I'd have to disagree that exploration stuff is not useful in understanding natural events. The e-book, for the most part, deals with exactly the same sorts of things global seismologists deal with, though the terminology is different at times. For instance, finite-difference codes for seismic wave propagation are commonly used to generate "forward models" and things like synthetic seismograms. A synthetic seismogram is the result of a finite difference approximation based on guesses about the source and the material the waves are passing through. Also, at the earthquake source the strains are very large so that more higher order terms have to be added to the wave equation, so that computer modelling is the only practical way to handle it. I'll point out a couple of related terms in exploration and global seismology to kind of illustrate the similarities involved: Exploration Term <-> Global Seismology Term Boundary impedance <-> Transmission/Reflection of waves across a discontinuity Ground Roll <-> Surface waves Deconvolution <-> Inversion ****************************************************************************** John Hernlund E-mail: 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 From: Roger Baker Subject: Torsion seismos Date: Fri, 26 Mar 1999 13:54:31 -0600 Friends, As some may know, torsion fiber instrumentation is a wonderful principle and the basis for some of the most sensitive instruments known = to physics. The force of gravity was first directly measured this way centuries ago, as one example. Torsion seismometers apparently represent a most interesting technologic= al dead end in the history of seismometers. Actually it may not be a dead topic, but I rarely see it discussed except as a curiosity of early seism= ic instrumentation. Such instruments are termed torsion seismometers and hav= e been used for both vertical and horizontal acceleration force detectors, although they seem most particularly suitable as detectors of horizontal motion. They are usually fairly small in size. =20 I will help introduce the topic with a few quotes from the seismic literature and then describe a few experiments of my own. It should be noted that torsion horizontals of this type are usually used as strong motion detectors, but I think this need not be so. Beniott believed they had potential as horizontal teleseismic instruments, as indicated below. (This paragraph immediately follows a discussion of the massive sizes of early seismometers in Elementary Seismology by Charles Richter, 1958, pag= e 222). =93Such great instruments are actually less effective than the relatively tiny torsion seismograph developed by Anderson and Wood in 1922. This instrument uses photographic recording; a static magnification of 2800 wi= th a pendulum period of 0.8 second is obtained with an assembly which, case and all, stands only a foot high. A metal fiber suspension held taut by b= y a weight is attached to the side of a copper cylinder (mass less than a gram!) which can rotate around the fiber against the restoring force of torsion. Damping, somewhat less than critical, is applied by eddy current= s induced in the copper as it moves in the field of the permanent magnet. T= he copper cylinder carries a small mirror for recording. The instrument is very satisfactory in the investigation of local earthquakes, for which it was designed. A similar torsion instrument was independently designed and put to the same purpose by Nikiforov in the Soviet union=94.=20 Next from =93Advances in Geophysics=94 , vol. 2, 1955 by Hugo Benioff, th= ere is a section on torsion seismographs, on pp 220-224. "... In spite of the disadvantages mentioned above, the 0.8 second period torsion seismograph with static magnification of 2700 has proved to be a stable and useful instrument for the recording of the horizontal componen= t of the stronger local earthquakes. Its limited magnification and the lack of a vertical component have seriously restricted its applicability. Likewise the 6-second period instrument with magnification of 800 has proved generally useful in the in the recording of some of the waves of large shallow earthquakes. In the opinion of the writer, the teleseismic form would be very much more effective if, instead of having a having a 6-second period, it were constructed with a longer period and smaller magnification, approximately the same as the corresponding constants of t= he Milne-Shaw instrument--the magnification being determined by the maximum tolerable tilt sensitivity. The shorter 6-second period was chosen as a result of an erroneous conclusion concerning the transient behavior of displacement-type seismometers, which in turn was a result of an incorrec= t assumption as to initial conditions in the solution of the differential equation of the seismometer as given by Anderson and Wood=94. So there we have it from Hugo Beniott, himself a master of seismic instrumentation design. The torsion horizontal was likely never properly optimized for teleseismic work due to a mathematical error by its invento= rs. =20 In fact, at least a prototype of the instrument can be rigged up in a few hours from very simple parts. The basis for the instrument is nothing mor= e than a fine vertical wire under tension. I used a fine (about .005") manganin wire, but any strong steel wire such as a guitar string would probably work, under a few pounds of tension so it makes a musical note when plucked. I mounted it on a rectangular cross section wooden stick about a foot long drilled with sideways holes near the ends so that a wir= e wrapped around the screws can be tensioned by turning the screws, much li= ke pegs that tension a guitar string.=20 Then I epoxyed two overlapping squares of glass about 2 inches square to the wire in about its center region so that the squares trap the wire nea= r one of their edges and the glass square extends sideways like a flag when the wire is vertical. Adjustments to the near-vertical position of the wi= re is extremely important in determining the behavior of the instrument. The stick is rigidly mounted in a vertical position on a pine board about 6 inches square and surrounded by a tall glass case made from glass strips bonded with silicone rubber to eliminate the effect of air currents. Thre= e vertical brass screws with wingnut tops threaded through undersized holes in the wooden base outside the glass enclosure allow the vertical tilt of the wire to be adjusted quite precisely. Obviously the end result will be that the glass plate, weighing perhaps a= n ounce, will swing around the wire from side to side as the wire is tilted slightly. When the wire is tilted forward, the plate will hang and swing like a garden gate. Slow seismic acceleration perpendicular to the face o= f the glass plate will cause the plate to swing sideways with an undamped oscillatory motion.=20 As the wire is brought more vertical the period of swing will lengthen. Finally as the wire is tilted backwards, the position of the plate will = be bistable. At some intermediate point, the position- restoring force due t= o the torsion of the wire to one position will just equal the bistable tendency of a slight backward tilt and the net position restoring force will be extremely weak. Since the restoring force on the unbalanced mass = is then so slight, the period of oscillatory rotation around the wire should lengthen to infinity, in theory.=20 In practice, the useful feature of such an instrument is that there are = no bearings or pivots to fuss with, merely one taut vertical wire, and that = a simple adjustment of, mostly, one screw controls the oscillation period. = By careful adjustment, I have got the oscillation period to be as long as 30 seconds, but this is not very stable due to ground tilt drift or whatever. A 15 to 20 second period might be more practical, while still being well-matched to the periods of teleseismic events. As Beniott states, th= e instrument is an extremely sensitive tilt meter as well as being a sensor of horizontal motion along one horizontal axis. In fact , it is mainly du= e to slight shifts in tilt that prevent the instrument from being adjusted = to very long periods. =20 So there we may have the basis of an instrument that, with further refinements, could=20 possibly match the characteristics of the Lehman, but in a smaller, easier-to-build package. I determined the physical characteristics of the adjustments by attaching a small mirror to the forward edge of the glass plate, and then bounced a laser pointer beam off of the mirror and onto a wall through the glass case.=20 In common with a Lehman, the horizontal position of the beam (or plate) i= s inclined to drift sideways a little due to tilt or temperature. As with a Lehman, a magnet and coil sensing arrangement could make the instrument more or less blind to slow drift while it remains sensitive to faster motion. Also, such an instrument would be a good candidate for optical displacement detection, using a small aluminum flag mounted on the plate = in conjunction with either LEDs or laser pointer mechanisms for optical displacement detection. But given the fact that this would still leave th= e instrument sensitive to slow tilt, this torsion seismometer would appear = to be a good candidate for force feedback positioning of horizontal displacement, especially since the instrument is physically small. Presumably thermal drift, which is usually troublesome in a vertical would be less serious in such a horizontal, in common with = a Lehman. Force feedback would have the dual benefit of both introducing the very small constant force needed to compensate for tilt and drift and also the more important function of eliminating oscillation. An appropriate force feedback arrangement would be very similar to that used by my Hi-Q vertic= al on my web page at:=20 http://www.eden.com/~rcbaker --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 From: Stephane Sol Subject: SAC Date: Fri, 26 Mar 1999 15:34:35 -0500 Hi all, I hope that someone is familiar with SAC. I am trying to use the SAC signal stacking subprocess but the Sac manual shows only the commands but it doesn't give some examples so it takes a lot of times to try to understand how it works. So I will be very pleased if somebody can show me some examples using sss. Thanks in advance. take care and have a great week-end. stephane _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Karl Cunningham Subject: Leaf Spring Force vs Deflection Tests Date: Fri, 26 Mar 1999 15:09:30 -0800 Brett and others -- This morning I tested a leaf spring's force vs. deflection and found it to be a straight line within the limit of my instrumentation (about 0.25%). The measurement was of the force exerted by a 101.6mm x 304.8mm x .794mm (4x12x.031 inches) leaf spring bent so that its ends were approximately 125mm apart. Under this condition, the spring force was 113.3 Newtons. The spring constant was about 4.7 Newtons per millimeter of deflection, over a range of 124mm to 126mm. +/- 1mm was the limit of my setup. The setup was the same as described in my earlier article on temperature testing ( http://www.jps.net/karlc/lstests.pdf ), with the addition of a device to adjust the length of the tension wire. The force and deflection numbers here are for the spring itself, but the measurements were made at the end of the reaction arm and multiplied by the ratio. There are quite a few flexures in the setup with very short free length to bend (less than ..15mm), which might be contributing to (or the majority of) the spring constant measured here. Any thoughts? Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: Re: Guitar suspensions Date: Fri, 26 Mar 1999 19:07:12 -0600 (CST) Ted, Getting a national anthem out of a seismic system won't be easy. The closest we have come is with audio carrier telemetry, where each station or component has its own tone that is FM modulated by the seismic signal, and mixed with up to 8 other tones for radio or phone line transmission. When one listens to the multiplexed line, ground movement at a given station will cause its tone to change frequency. If you have a rough idea of wich tone comes from what station and can identify the site, you can hear the chirping of the tone as the farmer cultivates the cotton in the field near New Madrid, or a long wailing tone as heavy surf pounds the shore near the station YAKAK in the Aleutians. We could "hear" an approaching storm from the west when all the data from the stations on Tanaga Island would wail from the wind noise. On a very rare occasion in the Aleutians, where we had tens of events per day, I have heard an actual earthquake modulating the carrier tones. Its kind of spooky, because you generally don't feel the quake where you are. The only particularly "national" problem we had with carrier tones was with the telemetry network in Tadjikistan. We would come in to the institute (TISS: Tadjik Institute for Seismoresistive construction and Seismology, in Dushanbe (USSR): AKA how to make mud bricks better than the ancient Persians did) and find our data trashed and hear a "brrat--brrat" noise on our telemetry phone lines ... a busy signal. So we would call the exchange and explain that the lines were in use and busy. The reply was that if the lines were busy, they SHOULD have a busy signal on them. After much shouting and a change to the local language, the busy signal was removed and our carrier tones could be heard. Until someone else at the exchange heard the tones and re-connected the busy signal. We eventually replaced the dedicated phone line (which, in a country with few working telephones, was costing a fortune anyhow) with a radio link. 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 From: Steve Jones Subject: Re: GPS Antenna Date: Fri, 26 Mar 1999 19:57:02 -0800 pouellette wrote: > > Sorry, I'm not familiar with that connector, however I have a friend who > just got > a oncore eval kit and I will check with him..The antenna is not > waterproof but can be inserted into a empty cd case & filled with > silicon or epoxy to weatherproof. > Peter > > Larry Cochrane wrote: > > > Peter, > > > > Thanks for the information, I'll add a link to your web page. Can you > > supply the RA/OSX RF connector used on the ONCORE unit? I don't see it > > listed on your web page. Also, can the unit be mounted outside? > > > > -Larry Cochrane > > Redwood City, PSN > > > > > > At 11:08 AM 3/17/99 -0500, you wrote: > > >For a lower-cost antenna, see my website: http://www.sawcenter.com/gpsant.htm > > >.Its an active antenna with your choice of connectors starting at $19.95 ea. > > >Peter > > > > _____________________________________________________________________ > > > > 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 Larry - I use the ONCORE receiver in a project, and have bought the OSX connector to plug into the receiver's pcb from Digi-Key - it is also known as a MCX connector, for RG316 cable - the D-K part # is (was last time I purchased them) J534, also R.F. Johnson part # 133-3403-006...hope this helps... Steve Jones _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: Re: Leaf Spring Force vs Deflection Tests Date: Fri, 26 Mar 1999 23:19:38 -0500 Karl, Thanks for running the numbers on the spring for me. I plugged in the dimensions and did a quick curve fit on the data I got. Result: Force = +0.001 L^2 - 0.5919 L + 184.41 N (L in mm) dF/dL = 0.002 L - 0.5919 N/mm So at L = 125 F = 126.0 N and at L = 125 dF/dL = -0.342 N/mm One item of interest is that the stress in your spring appears to be getting over 200 kpsi at the center. Does it lie flat when you unload it? If not, that could easily account for the difference between your 113 and my 126. This one should be coming out a little closer than the 10% we're seeing, though it isn't bad at all. Is your spring constant value maybe -4.7 N/cm ? That would be somewhat higher than I calculate, but not quite14x higher. Again, that would probably be affected a lot by any initial curvature in the spring, but I'll have to admit, I don't have any sense in which direction that effect would be. The calculations to accomodate the effects of initial curvature, unless it's starting out as a circular arc (which it wouldn't be), are rather nasty. On the spring itself, 0.031" seems awfully thick = high stress. I was thinking of using something like 0.015" with a tad less mass, as even Sean-Thomas' 0.018" seemed to be stressed enough that he was seeing a little creep. Though what he was describing might well settle down after a few months or so of operation. Again, thanks Karl for taking the time to check this out. Brett At 03:09 PM 3/26/99 -0800, you wrote: >Brett and others -- > >This morning I tested a leaf spring's force vs. deflection and found it to >be a straight line within the limit of my instrumentation (about 0.25%). > >The measurement was of the force exerted by a 101.6mm x 304.8mm x .794mm >(4x12x.031 inches) leaf spring bent so that its ends were approximately >125mm apart. Under this condition, the spring force was 113.3 Newtons. >The spring constant was about 4.7 Newtons per millimeter of deflection, >over a range of 124mm to 126mm. +/- 1mm was the limit of my setup. > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Earthquake Amplifiers Date: Sat, 27 Mar 1999 22:19:34 -0800 Hi There, I got this email today. Pretty funny.... I informed Cameron that my amplifier board is used to record earthquakes, not a car stereo amp. -Larry Cochrane Redwood City, PSN >Date: Sun, 28 Mar 1999 18:03:05 +1200 >From: Karen Robertson >Organization: Original Lusty Lloyd Loom Furnc >X-Mailer: Mozilla 2.02E-XTRA (Win95; I) >To: cochrane@.............. >Subject: Earthquake Amplifiers >X-URL: http://psn.quake.net/onlinedocs/eqampdoc.html > >Dear Sir, > >I was wondering if you would be able to help me with a problem I have. I >have an Earthquake 400TXO Amplifier in my car. I lent this to my friend >who has blown my amp. I was wondering if you would be able to fix it or >know anybody who would know how to. Also could you please let me know of >the replacement cost. > >I await your reply, >Cameron Robertson > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Tom Genereaux Subject: Re: Earthquake Amplifiers Date: Sun, 28 Mar 1999 00:42:57 -0600 On Sun, 28 Mar 1999, you wrote: Well, I always knew those amps were really portable seismic generators. :) Tom G > Hi There, > > I got this email today. Pretty funny.... I informed Cameron that my > amplifier board is used to record earthquakes, not a car stereo amp. > > -Larry Cochrane > Redwood City, PSN > > > > >I was wondering if you would be able to help me with a problem I have. I > >have an Earthquake 400TXO Amplifier in my car. I lent this to my friend > >who has blown my amp. I was wondering if you would be able to fix it or > >know anybody who would know how to. Also could you please let me know of > >the replacement cost. > > > >I await your reply, > >Cameron Robertson > > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: horizontal sensitivity Date: Sun, 28 Mar 1999 01:40:19 -0600 (CST) Barry, Regarding your question about the mass position or sensitivity of your new VBB horizontal. As I have noted before, horizontals are much more sensitive to tilt than verticals ... by the square of the angle rather than the angle. This makes working with them much more difficult, which is why they are frequently avoided if a vertical will provide the data. This is true even for 1 hz sensors. It is also the reason the Lehman and SG sensors are difficult to operate at high sensitivities in residential settings. In your case, the tilt sensitivity of a VBB is also a function of the square of the operating period Tn. (where z is the displacement, and phi is the tilt) z = (g * Tn^2 / 4 * pi^2) * phi (horizontal) (which is also true for the vertical: z = (g * Tn^2 / 8 * pi^2) * phi^2) (vertical) So when you push the operating period from 20 to 100 seconds, the sensitivity increases by 25. Even a modest increase demands a good site for the instrument. The WWNSS (worldwide network of standard seismographs) originally tried to operate the long period sensors at 30 seconds, but so many were always at the stops that they backed off to 15 seconds. You asked if the VBB could be configured as a force balance. It already IS a force balance system. With a long period response, the loop gain is not large; configuring a narrower response will increase the loop gain (I think Brett's analysis shows this). The loop gain at DC of the 90 second here is about 20 (the change in the displacement detector output when the feedback is opened.) You can test the tilt sensitivity using your transit leveling screw, which I guess is something like 40 threads/inch. In the above formula, "phi" is the angle in radians, so if you turn the screw one turn and if the base support width is 10 inches, the tilt is 1/40" divided by 10", or 0.0025 radians. The displacement then is 0.062cm times the square of the period. If Tn is 10 seconds, it is 6.2cm; if Tn is 100 seconds, one turn of th 40 tpi screw will try to move the boom 620 cm. Even if 1/100 turn can be used, the displacement is still quite large. THis is why VBB instruments have a feature that allows a shorter period to be switched in for setup at installation, and a motor-driven lever of 100:1 to level the sensor in operation. A typical tilt noise level for the 360-second STS-1 is equilavent to about 6 nanoradians. For practical operation of a home-made VBB, an operating period of 20 to 40 seconds would be preferred. 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 From: robert barns <75612.2635@..............> Subject: Hernlund web site Date: Sun, 28 Mar 1999 09:55:49 -0500 Hi gang, I explored John Hernlund's web site at www.public.asu.edu/~hernlund I found it handsome, very friendly and informative. Give it a try. Bob Barns _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: S-T Morrissey Subject: Ms 6.6 N. India Date: Sun, 28 Mar 1999 21:27:14 -0600 (CST) U.S. GEOLOGICAL SURVEY NATIONAL EARTHQUAKE INFORMATION CENTER World Data Center A for Seismology The following is from the United States Geological Survey, National Earthquake Information Center: Preliminary hypocenter for earthquake of 1999 Mar 28, XIZANG-INDIA BORDER REGION: latitude 30.5 degrees north, longitude 79.3 degrees east, origin time 19 05 13.6 utc, depth normal, magnitude 6.6 ms. No reports of damage or casualties have been received at this time. ------------------------------------------------------------------- _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "J. D. Cooley" Subject: Re: Ms 6.6 N. India Date: Sun, 28 Mar 1999 20:15:19 -0800 At 09:27 PM 3/28/99 -0600, you wrote: > U.S. GEOLOGICAL SURVEY NATIONAL EARTHQUAKE INFORMATION CENTER > World Data Center A for Seismology > >The following is from the United States Geological Survey, National >Earthquake Information Center: Preliminary hypocenter for >earthquake of 1999 Mar 28, XIZANG-INDIA BORDER REGION: latitude >30.5 degrees north, longitude 79.3 degrees east, origin time 19 05 >13.6 utc, depth normal, magnitude 6.6 ms. No reports of damage or >casualties have been received at this time. >------------------------------------------------------------------- The Associated Press is reporting that at least 10 people are dead. "JD" _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Ted Blank Subject: Re: Earthquake Amplifiers Date: Mon, 29 Mar 1999 08:37:03 -0800 (PST) The logical extension of Edward's vision for the PSN is a seismic recorder in every car. Every bridge and overpass would be guaranteed to have full coverage in every quake. Larry could be the supplier of the new, improved version of his amp which would fit in the radio slot. Critical damping is already provided by the shock absorbers. And there's probably room on the card for 200 watts per channel stereo system. There's a great business opportunity here Larry, grab it. :-) Ted Blank San Jose, California On Sat, 27 Mar 1999, Larry Cochrane wrote: > Hi There, > > I got this email today. Pretty funny.... I informed Cameron that my > amplifier board is used to record earthquakes, not a car stereo amp. > > -Larry Cochrane > Redwood City, PSN > > >Date: Sun, 28 Mar 1999 18:03:05 +1200 > >From: Karen Robertson > >Organization: Original Lusty Lloyd Loom Furnc > >X-Mailer: Mozilla 2.02E-XTRA (Win95; I) > >To: cochrane@.............. > >Subject: Earthquake Amplifiers > >X-URL: http://psn.quake.net/onlinedocs/eqampdoc.html > > > >Dear Sir, > > > >I was wondering if you would be able to help me with a problem I have. I > >have an Earthquake 400TXO Amplifier in my car. I lent this to my friend > >who has blown my amp. I was wondering if you would be able to fix it or > >know anybody who would know how to. Also could you please let me know of > >the replacement cost. > > > >I await your reply, > >Cameron Robertson > > > > _____________________________________________________________________ > > 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 From: Karl Cunningham Subject: Re: Leaf Spring Force vs Deflection Date: Mon, 29 Mar 1999 12:08:15 -0800 Hi Brett -- I made a couple of mistakes in my data reduction last week. But it's now even further from your calculations. New revised numbers: The spring force at 125 mm is 167 N, and the dF/dL is -4.8 N/mm. But, in the mechanism there are 16 flexures of 0.003" stainless, each about 0.09" wide, and each with a free length of less than 0.005". This is likely the predominent part of dF/dL and may be a substantial part of the initial force as well. I don't think the spring quite lies flat if I let it, which I haven't done in quite a while. And yes a thinner spring would work better. Stainless shim stock is available in a variety of thicknesses, so I may experiment with some of that. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Karl Cunningham Subject: Re: Leaf Spring Force vs Deflection Date: Mon, 29 Mar 1999 15:12:45 -0800 Brett -- This has not been my week! I just found another mistake in my data -- I used the wrong ratio of the reaction arm. This puts the 125 mm force at 133 N -- much closer. The dF/dL is -3.8 N/mm -- still way off but probably mostly due to the flexures. Karl Cunningham La Mesa, CA. PSN station #40 karlc@....... _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Larry Cochrane Subject: Re: Pile driving near me... - Update Date: Mon, 29 Mar 1999 21:19:07 -0800 All, The pile driving is now complete. Last week I collected over 50 megabytes of data using up to 4 short period vertical sensors spaced at various distances from the driver. Heres what I used to record the data; Since my A/D card and software only record up to 100 samples per second (SPS) I used a Symmetric Research A/D board. This board can record up to 64 channels at high sample rates. I record 4 channels at ~500 SPS and some data was recorded at ~250 SPS. For data logging I use a program called XRTP, a program from the IASPEI software package, and, I am using WinQuake and MATLAB to look at the data. Edward Cranswick is also looking at the data using his tools. One of the people Edward works with is hopefully going to look at the data using SASW (see below). For sensors I used 3 L28s (4.5hz) and 1 L22 (2hz, only the vertical component). I used two of my Amp boards with the low pass filter set to 50hz, For sensor placement, the first thing I did is a huddle test. This is where you place all of the sensor together to make sure they all have the same response. I then placed the 3 L28 ~25 feet (~7.6m) apart in my back yard with the array pointing to the pile driver. The sensors where placed in a hole about 1 foot deep. Doing some quick look at the data I could see that the shear wave had a velocity around 309 meters / second through the array. I was expecting much higher velocities! The last day of pile driving I was able to extend my baseline of sensors. Two of the L28s where moved to my neighbor's yards, one on each side of me. This extended the distance to 75 feet (22.9m), 150 feet total between each L28 sensor. I then placed the L22 sensor at the end of the street toward the driver. This sensor was placed 183 feet (55.77m) from the first L28 sensor in my neighbors yards. This gave me a total distance of ~333 feet (101.5m) from the first sensor to the last one. What I have found so far is the P wave has a pretty constant velocity of 2.3km / sec through my array. The shear wave velocities are all over the map! As noted above, I was seeing a velocity of around 300 m/s when the sensors where in my yard. After moving the sensors, I got a velocity of ~140 m/s between the first sensor and the next one 183 feet away. The velocity between the next three sensors is around 228 m/s and fairly constant between sensors #2 and #3 and #3 and #4. One other test I did was too look at the difference between placing a sensor in the ground, another on the cement slab my house is on, and one on the wood floor in my sensor room. After the huddle test, I keep sensor #1 in the ground. Another one was placed on the cement, a few feet from senor #1. Sensor #3 was placed in my sensor room, next to my Lehman and SG sensor. I used epoxy to hold the sensor to the cement and wood floor. The good news is I don't see any difference between the three sensors. I placed two GIF files showing the time (http://www.seismicnet.com/piledrive/test2time.gif) and frequency domain (http://www.seismicnet.com/piledrive/test2fft.gif) of the three sensors. The top window is the sensor in the ground, middle is the sensor on the cement and the bottom is the sensor on the wood floor. That's it for now.... Regards, Larry Cochrane Redwood City, PSN At 07:56 AM 3/13/99 -0800, Doug Crice wrote: >Determining your local geology from pile driving. > >The simplest approach (theoretically) is to measure the interval between >the pile impact and the seismic arrival at a series of points between >the pile driver and your seismograph. Logistically, it's a little >inconvenient because you would have to move your seismometer a number of >times (say to points every 10 meters between the machine and your house) >and also time the impact precisely to find the interval time. The >calculations aren't too complicated, but too much for this space. The >waves refract through the ground, going deeper as the distance increases >and it becomes quicker to go down to the higher velocity rock. > >Logistically more convenient and mathmatically elegant is to locate a >vertical seismometer a little ways toward the pile and another one a >little further away. Record both at the same time, them do a >cross-spectral analysis of velocity verses frequency. The short >wavelength surface waves travel at shallower depths than the long >wavelengths, and the velocities are depending on the shear strength of >the material. From the shear wave velocities, you can deduce the shear >strength and thus the material types and foundation characteristics. > >The whole process is called "Spectral Analysis of Surface Waves" or more >commonly SASW, and it is being adapted to exploration geophysics. One >of the beauties is that shear wave velocities are much more diagnostic >of material types than P wave velocities. Do an internet search for >SASW and you should find some papers. Interestingly enough, the method >was developed by earthquake folks and is being adapted by engineers, >even down to testing concrete pavement. >-- >Doug Crice web site http://www.georadar.com >GeoRadar Inc. e-mail dcrice@............ >19623 Via Escuela Drive phone 408-867-3792 >Saratoga, CA 95070 USA fax 408-867-4900 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Doug Crice Subject: Re: Pile driving near me... - Update Date: Tue, 30 Mar 1999 07:03:00 -0800 Larry, Those ain't shear waves you're looking at, they're surface waves. Well, OK, technically a surface wave is a shear wave, but we usually talk about shear waves as body waves. The reason they seem slow is that the velocity is dependent on the near surface material, which is a lot looser than the stuff earthquakes normally travel through. Remember that you can split the surface waves up into different wavelenths and look at the velocity of each component. The depth of penetration is approximately equal to the wavelength. That's why you get so much variation, the soil is either different or deeper at the various sites. Search the web for SASW (common term for spectral analysis of surface waves) for more info. -- Doug Crice web site http://www.georadar.com GeoRadar Inc. e-mail dcrice@............ 19623 Via Escuela Drive phone 408-867-3792 Saratoga, CA 95070 USA fax 408-867-4900 _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: Brett Nordgren Subject: Loop measurements Date: Wed, 31 Mar 1999 08:16:04 -0500 To all, I put a new .pdf on my Web page which describes how to measure and interpret the loop gain of a feedback seismo, using an oscillator and oscilloscope. lpmeas.pdf 25k (as in Loop Measurements) At http://members.home.net/nordgren/public/ Hope you find it helpful, Brett _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: angelr Subject: inverted data?? Date: Wed, 31 Mar 1999 10:46:28 -0500 Hi, I have two verticle devices and when I get a event on one device the P starts up and on the other the P starts down. My question is: If I go near the device and drop a big weight, letīs say a bowling ball, which way should I see the first response to the ball hitting the ground. Should trace on the screen go down or up? Thanks, Angel _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Lahr Subject: Re: inverted data?? Date: Wed, 31 Mar 1999 10:02:45 -0700 (MST) Angel, By convention for paper seismic records: Vertical component: if the ground moves up, then the pen should move toward the top of the paper. North-South component: if the gound moves North, then the pen should move toward the top of the paper. East-West component: if the gound moves East, then the pen should move toward the top of the paper. I believe the convention for digital data it up, north, and east produce positive counts. Dropping something on the gound near the seismometer will cause the gound to move down and so should the pen on the paper. JCLahr > Hi, > > I have two verticle devices and when I get a event on one device the P > starts up and on the other the P starts down. My question is: > > > Thanks, > > Angel _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: John Hernlund Subject: Re: inverted data?? Date: Wed, 31 Mar 1999 10:56:58 -0700 (MST) On Wed, 31 Mar 1999, angelr wrote: > I have two verticle devices and when I get a event on one device the P > starts up and on the other the P starts down. My question is: > If I go near the device and drop a big weight, let=B4s say a bowling > ball, which way should I see the first response to the ball hitting > the ground. Should trace on the screen go down or up? In addition to the other response: Remember also that P arrivals can cause the ground to move up or down for t= he first arrival... Intuitively the bowling ball will cause a downward pulse = of the ground that travels away from the drop point. If you want your up and down to correspond to ground up and down then change polarities until it do= es.=20 John Hernlund E-mail: hernlund@....... WWW: 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 From: "Al Allworth" Subject: Re: Loop measurements Date: Wed, 31 Mar 1999 10:10:41 -0800 It looks like a vector voltmeter would be useful here. I passed up one in a surplus store not long ago at $25.00. ____________________________________ Al Allworth allworth@.............. Gold Beach On The Beautiful Southern Oregon Coast ____________________________________ ----- Original Message ----- From: Brett Nordgren To: PSN-L Mailing List Sent: Wednesday, March 31, 1999 5:16 AM Subject: Loop measurements > To all, > > I put a new .pdf on my Web page which describes how to measure and > interpret the loop gain of a feedback seismo, using an oscillator and > oscilloscope. > > lpmeas.pdf 25k (as in Loop Measurements) > > At > > http://members.home.net/nordgren/public/ > > Hope you find it helpful, > > Brett > > > _____________________________________________________________________ > > 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 From: Brett Nordgren Subject: Re: Loop measurements Date: Wed, 31 Mar 1999 13:51:45 -0500 Al, Sorry to hear that. Probably didn't work anyway, right? Actually, what is also useful is a tracking voltmeter or wave analyzer that outputs a signal and then measures just that frequency, usually down to microvolts. Don't know anymore what the brands are, but it is a gadget I've been looking for at the Ham/Computer flea markets. Brett At 10:10 AM 3/31/99 -0800, you wrote: >It looks like a vector voltmeter would be useful here. I passed up one in a >surplus store not long ago at $25.00. >____________________________________ > >Al Allworth allworth@.............. > >Gold Beach > >On The Beautiful Southern Oregon Coast > >____________________________________ > >----- Original Message ----- >From: Brett Nordgren >To: PSN-L Mailing List >Sent: Wednesday, March 31, 1999 5:16 AM >Subject: Loop measurements > > >> To all, >> >> I put a new .pdf on my Web page which describes how to measure and >> interpret the loop gain of a feedback seismo, using an oscillator and >> oscilloscope. >> >> lpmeas.pdf 25k (as in Loop Measurements) >> >> At >> >> http://members.home.net/nordgren/public/ >> >> Hope you find it helpful, >> >> Brett >> >> >> _____________________________________________________________________ >> >> Public Seismic Network Mailing List (PSN-L) >> >> To leave this list email listserver@.............. with the body of the >> message: leave PSN-L >> >> > > >_____________________________________________________________________ > >Public Seismic Network Mailing List (PSN-L) > >To leave this list email listserver@.............. with the body of the >message: leave PSN-L _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L From: "Al Allworth" Subject: Re: Loop measurements Date: Wed, 31 Mar 1999 11:13:54 -0800 Hi Brett and the group, It seemed to work OK. When both probes were connected to the same source it showed near zero phase. Some I have checked that way didn't read zero. I have a low freq. stectrum analyzer with a tracking oscillator but haven't tried it for checking feedback response yet. It goes down to a few hertz when in the hi res mode. ____________________________________ Al Allworth allworth@.............. Gold Beach On The Beautiful Southern Oregon Coast ____________________________________ ----- Original Message ----- From: Brett Nordgren To: PSN-L Mailing List Sent: Wednesday, March 31, 1999 10:51 AM Subject: Re: Loop measurements > Al, > > Sorry to hear that. Probably didn't work anyway, right? > > Actually, what is also useful is a tracking voltmeter or wave analyzer that > outputs a signal and then measures just that frequency, usually down to > microvolts. Don't know anymore what the brands are, but it is a gadget > I've been looking for at the Ham/Computer flea markets. > > Brett > _____________________________________________________________________ Public Seismic Network Mailing List (PSN-L) To leave this list email listserver@.............. with the body of the message: leave PSN-L