[SAC-HELP] Removing Instrument Response

Januka Attanayake jattanayake at yahoo.com
Sun Aug 28 14:29:18 PDT 2011


I think your original seismograms are velocity and since you are using "to none" your out put is displacement. Try doing a dif after the deconvolution and then compare.
 
_______________
Serenity isn't freedom from the storm, but peace within the storm

Januka Attanayake 
Earthquake Seismology & Economics
The University of Connecticut 
354, Mansfield Road 
Storrs, CT 06269-2045
Tel:860 486 3914 (Lab - P405)

Home page: http://sites.google.com/site/janukaattanayake/
Research group: http://www.phys.uconn.edu/research/geophysics/index.html








________________________________
From: James Smith <jsmith82 at gmail.com>
To: sac-help at iris.washington.edu
Sent: Sunday, August 28, 2011 5:19 PM
Subject: [SAC-HELP] Removing Instrument Response

Hello:

I have a set of Canadian seismograms that I need to remove the
instrument response from. I have converted the seed files to sac files
and extracted the RESP files.  I am using the following commands in
SAC:

sac> file.sac
sac> rmean
sac> rtrend
sac> taper
sac> trans from evalresp to none freq .01 .015 2 5

When I use the evalresp file I get the following output:

Nominal Calper not set. Setting Nominal Calper to -999.000000 to
match Wfdisc Calper
Sensor Calper not set. Setting Sensor Calper to 1.000000 to match Wfdisc Calper
Response appears to be Un-Normalized.
Waveform appears to be unscaled.
Wfdisc calib value is (769600000.000000).
Waveform multiplied by 1.000000 after deconvolution.

The deconvolved seismogram usually doesn't resemble the original. My
understanding is that removing the instrument response should not in
general change the shape of the seismogram. I've tried applying
various bandpass filters without much luck.

Can anyone tell me if I am missing a step or what could be responsible
for my problem?

Thanks,

James Smith
Colorado State University
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