PSN-L Email List Message

Subject: Inverse filtering example
From: Bob McClure bobmcclure90@.........
Date: Sun, 13 Mar 2011 16:09:40 -0400


  I use inverse filtering to restore long-period response to my medium
period sensors. On major events, even geophones can be transformed into
long-period sensors.

  For example, I downloaded the following files:

110311.054500.sobe.psnMw8.9
8750km from Sonderborg, Denmark, Near East Coast of Eastern Honshu,
Japan (GIF Image)
110311.054500.sobn.psnMw8.9
8750km from Sonderborg, Denmark, Near East Coast of Eastern Honshu,
Japan (GIF Image)
110311.054500.sobz.psnMw8.9
8750km from Sonderborg, Denmark, Near East Coast of Eastern Honshu,
Japan (GIF Image)

  I inverse filtered from the original period of 0.22 seconds to 20 seconds
and posted the following volume file:

110311.055500.sobx.psn*
M8.9 8750km from Sonderborg, Denmark [Inverse Filtered], Near East
Coast
of Eastern Honshu, Japan (GIF
Image)

which can be looked at or downloaded from
http://www.seismicnet.com/cgi-dos/event.exe

  If you integrate the data, you get peak displacements in the 3 to 4 mm
range, which seems about right.

  My inverse filter utility program, WQFilter.exe, can be downloaded from
http://sites.google.com/site/bobmcclure90

Bob
=A0 I use inverse filtering to restore long-period response to my medium pe=
riod sensors. On major events, even geophones can be transformed into long-=
period sensors.

=A0 For example, I downloaded the following files:
110311.054500.sobe.psn Mw8.9 8750km from Sonderborg, Denmark, Near Ea= st Coast of Eastern Honshu, Japan (GIF Image)
11= 0311.054500.sobn.psn Mw8.9 8750km from Sonderborg, Denmark, Near East C= oast of Eastern Honshu, Japan (GIF Image)
11= 0311.054500.sobz.psn Mw8.9 8750km from Sonderborg, Denmark, Near East C= oast of Eastern Honshu, Japan (GIF Image)

=A0 I inverse filtered from the original period of 0.22 seconds to 20 s= econds and posted the following volume file:

110311.055500.sobx.psn * M8.9 8750km from Sonderborg, Denmark [Inverse Filtered], Near East Coas= t of Eastern Honshu, Japan (GIF Image)

which can be looked at or downloaded from http://www.seismicnet.com/cgi-dos/event.exe<= br>
=A0 If you integrate the data, you get peak displacements in the 3 t= o 4 mm range, which seems about right.

=A0 My inverse filter utility program, WQFilter.exe, can be downloaded = from http://sites.goo= gle.com/site/bobmcclure90

Bob

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