[time-nuts] USGS: GPS for seismic work

[DaveH]

They also use GPS units for tectonic shift.  Put a unit on each plate and
measure the difference between them.  When it gets to be a large enough
number, something, somewhere will slip and you will have a quake.

Dave  

> -----Original Message-----
> From: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] On Behalf Of Hal Murray
> Sent: Saturday, May 19, 2012 18:09
> To: time-nuts at febo.com
> Subject: [time-nuts] USGS: GPS for seismic work
> 
> 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-r
> esearch.html
> 
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
> 
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