There is a Dallas Instrument Seismograph on eBay at
http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&tc=ps&item=226938824

This is a blast monitoring seismograph, designed to automatically
trigger in response to vibrations over the triggering level.  This
particular one records on a cassette tape.  I don't think it's of much
use as is, but these things normally include 3 orthogonal geophones in a
single package (contrary to what the description says).  I may be
mistaken, but they normally use 4.5 Hz phones and add some frequency
compensation to get response down to 2 Hz.  This unit was for sale last
month, and apparently didn't move.

It might be worth buying for the 3-component sensor and shipping case if
it's cheap enough.  The geophones would be normal petroleum exploration
sensors.

Doug


_____________________________________________________________________

Public Seismic Network Mailing List (PSN-L)