PSN-L Email List Message
Subject: Re: My Kermadec Islands Region earthquake recording
From: ChrisAtUpw@.......
Date: Wed, 17 May 2006 05:53:52 EDT
In a message dated 17/05/06, jonfr500@......... writes:
> did clean everything above 1Hz out of the recording to actually see
> the signal. I did the same thing with the eastern siberia earthquake in
> April, that I detected. Even if the response falls flat below 2Hz,
> there seems to be surprising lot of data below 2Hz.
Hi Jon,
The geophone response will fall to 1/5 at 2Hz, to 1/20 at 1 Hz and to
1/100 at 0.45 Hz. It does not 'fall flat', more like it takes a 'nose dive'!
If you get strong enough seismic signals you will certainly see them
to below 1 Hz. You may also see locally generated noise as the result of the
quake.
The geophone compensator circuits are designed to go from the 20 / 10
Hz of the low pass filter down to 0.45 Hz, flat to velocity. You do get some
additional noise, but it is quite small. This does enable you to detect
teleseismic P and S waves with a 4.5 Hz geophone.
Regards,
Chris Chapman
In a message=20=
dated 17/05/06, jonfr500@......... writes:
I did clean everything abov=
e 1Hz out of the recording to actually see
the signal. I did the same thing with the eastern siberia earthquake in
April, that I detected. Even if the response falls flat below 2Hz,
there seems to be surprising lot of data below 2Hz.
Hi Jon,
The geophone response will fall to=20=
1/5 at 2Hz, to 1/20 at 1 Hz and to 1/100 at 0.45 Hz. It does not 'fall flat'=
, more like it takes a 'nose dive'!
If you get strong enough seismic si=
gnals you will certainly see them to below 1 Hz. You may also see locally ge=
nerated noise as the result of the quake.
The geophone compensator circuits a=
re designed to go from the 20 / 10 Hz of the low pass filter down to 0.45 Hz=
, flat to velocity. You do get some additional noise, but it is quite small.=
This does enable you to detect teleseismic P and S waves with a 4.5 Hz geop=
hone.
Regards,
Chris Chapman
[ Top ]
[ Back ]
[ Home Page ]