G'day All, While hunting around for something else (can't remember what it was now) a couple of days ago, I found the PSN websites etc. I am interested in experimenting with a home-made seismograph and found the information available to be very useful. However, I have a few questions:- 1. All the seismograms I have seen on the sites show the P wave as being smaller than the S wave. As I understand it the P wave is longitudinal and the S wave is traverse, i.e. they are orthogonal. Question: Wouldn't the relative amplitudes then depend on the orientation of a horizontal seismograph (i.e. a Lehman)? I think I can understand that a vertical seismograph would show the higher S wave close to an event, but the situation for a horizontal one has me puzzled. 2. I would like to try and build a vertical seismograph using some Aura shaker transducers I have. I have tested the resonance frequency and they appear to be around 40Hz. I intend to try and make a vertical force-balance type which I understand is really an accelerometer. Question: What is the relative sensitivities and relative amplitudes of events of horizontal versus vertical seismographs? What are the relative pros and cons of vertical versus horizontal seismographs? Is there any disadvantage in using accelerometer (force-balance?) types versus displacement or velocity types of seismographs? 3. If I wanted to send a contribution to the supporters of this email reflector, who, where and how could I send it from here in Australia? Best regards Steve Olney QF56IK : Lat -33 34 07, Long +150 44 40) ============================================= HomePage URLs: http://www.zeta.org.au/~ollaneg Containing:- Laser Comms DX LF Experimentation Amateur Radio Astronomy ============================================= __________________________________________________________ Public Seismic Network Mailing List (PSN-L)
Larry Cochrane <cochrane@..............>