PSN-L Email List Message

Subject: Re: Large Response Coming in Now at 18:00 UTC
From: Brett Nordgren brett3nt@.............
Date: Mon, 03 Aug 2009 19:56:52 -0400


Bob

Now that I corrected the y-scale the plot from our 
vertical  http://bnordgren.org/seismo/090803.175000.bhz-pl.psn.gif  shows 
roughly 3mm/s peak,  which agrees pretty well with the values (assuming you 
meant mm/s) that you were seeing.  This is from near LA which is at about 
6.5 deg.  It's interesting that if you assume the predominant frequency was 
1/13 seconds, that should imply that the vertical ground motion at Dave's 
vault was about 6.2mm peak or 1.24 cm p-p.  That's a lot of motion!

For laughs, I uploaded the output from the high gain channel 
http://bnordgren.org/seismo/090803.175000.bhz-ph.psn.gif which clips at 
300um/s and indeed it clipped.  However, the low gain channel should be 
able to handle up to 1.5cm/sec peak.

Brett

At 11:28 AM 8/3/2009 -0700, you wrote:
>There are two events, the first one if listed as M 5.8, the second event 
>is M 6.9.  I recorded 2.6 mm of movement on the vertical channel, 3.8 mm 
>on the North channel, and 2.0 mm of movement on East channel.  My station 
>is only 3.43 degrees (381.14 km) from the event.
>
>Bob Hancock


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