[time-nuts] USGS: GPS for seismic work

[Hal Murray]

It wasn't hard to find the right people at the Open House.

GPS is interesting for big quakes.

Most seismometers measure acceleration.  It's a double integration to get 
displacement which is what they are used to working with.  Big quakes last 
longer which leads normal seismometers to get into troubles with drift.  GPS 
doesn't have any drift problems.  The cross over is somewhere in the mag 7-8 
range.

Japan has a large earthquake warning system.  On the big tsunami of last 
year, they weren't looking for long enough.  They estimated 7.9.  In 
hindsight, they probably could have gotten better data sooner by using GPS.

This news story says that they can see the disturbance in the ionosphere.
  http://www.cbc.ca/news/technology/story/2012/04/23/f-tsunami-research.html


-- 
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