Hi guys, 

I got here a little differently to the rest of you - I used to do the 
field work, but never quite knew what I was doing :-)

All this talk of gravity surveys reminds me of the days when I used to 
shoot seismic for a living - I never did, and still don't really 
understand how a La Coste and Romberg meter worked, but watching it 
working on a rolling ship, rolling 20 degrees port and starboard every few 
 seconds, and pitching the same fore and aft was a very impressive 
experience...

We once had a guy from LC & R on board running a course on the thing, but 
it was horribly complicated, and beyond understanding the basic principal 
that it was a fixed weight suspended on a zero length spring that would 
deflect by differing amounts according to the pull of gravity, I don't 
think anyone ever really understood it. Pity really cos we were surveying 
an area around Indonesia at the time which would have been interesting !!!

I do recall that it used missile gyros that were very expensive to replace 
and screamed horribly when they expired, usually for several days. I 
should imagine that the device must be obsolete now, though I guess there 
were few enough of them for them to be eagerly grabbed if they ever were 
surplus. 

Had an interesting trip off Taiwan shortly after a big quake over there in 
the mid 80s, couldn't work for several days because of all the residual 
noise that swamped our somewhat puny signal.

regards all,

Nick

__________________________________________________________

Public Seismic Network Mailing List (PSN-L)