Hello Bob & Brett ;
If you were looking only for first arrival times
Id think High gain is the way to go.
You must see the noise because the emerging
signal can sometimes be a part of the noise.
Many signals i get from this area seems
to attenuate the P wave in a way it arises
slowly out of the grass and in such a case
where exactly is the first arrival time.
Most not likely the time you actually see.
If somehow you could use a FFT to see
the first arrival time I think that may be
the way to go but since you need many
samples to use the fft it may not be possible
to see the exact arrival.
Does anyone know of processing routines
that will pull a signal out of the grass other
than a FFT routine ??


----- Original Message ----- 
From: "Brett Nordgren" 
To: 
Sent: Monday, August 03, 2009 5:02 PM
Subject: Re: Large Response. Corrected URL


Bob


For laughs, I uploaded the output from the high gain channel 
http://bnordgren.org/seismo/090803.175000.bhz-ph.psn.gif

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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