SAC Help

A forum for SAC users to exchange ideas and ask questions about SAC usage, installation, portability, etc.

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Active Message Threads for April 2008

2008-04-29 10:38:45
Hi, Sir First you have to know the unit of your data, count or m*m/s? also, the unit of the instrument response, rad/s or Hz(2*pi difference)? and then, which kind of instrument response, i.e., displacement, velocity or acceleration(2*pi*f difference)? the magnitude of different response may be different up to several orders. Your sincerely, Xu W. ************************************************ Dr. WeiWei Xu Institute of Geology and Geophysics Chinese Academy of Sciences P.O.Box 9825 Be… [more]
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Kenneth Macpherson
2008-04-23 15:31:57
Hello all, I have acceleration data in the Kinemetrics event file format (.evt) that I have converted to SAC using the companies K2SAC program. I am now going through the process of correcting the data and to be honest, this is my first attempt at this sort of thing! I have removed the mean and instrument response using RMEAN and TRANSFER, respectively. Now the waveforms look correct except that the amplitudes are orders of magnitude too high! Is there some kind of amplitude scaling step th… [more]
No replies
Александр Ж
2008-04-22 20:06:23
Good daytime. I have a very important question for me. Help me please to understand the next operation: I have the plot and I need to get the Y-value if I have X-value fixed. What function or operation in the SAC does it do? Thank you very much. Best regards, Alexander S. Zholondz (Saint-Petersburg State University, Saint-Petersburg, Russia)
No replies
Nadezda Kraeva
2008-04-18 23:15:29
Hi all,I attempt to apply a SAC Wiener filter to remove a noise. A design filter window is taken just before the first arrival. Tests show that an amplitude of the resulting signal is changed, sometimes up to order of magnitude, that makes this version of filter unsuitable for further spectral estimations and response specter analysis. Could you tell me, please, how to normalise the signal after the SAC Wiener filter application to get correct amplitudes?I use the 101.1 Version of SAC, in Fedor… [more]
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Geo .
2008-04-15 15:18:58
Thanks Brian, will try that... On Mon, Apr 14, 2008 at 3:07 PM, <> wrote: > Send sac-help mailing list submissions to > > > To subscribe or unsubscribe via the World Wide Web, visit > > or, via email, send a message with subject or body 'help' to > > > You can reach the person managing the list at > sac-help-… [more]
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Geo .
2008-04-11 05:52:16 - 2008-04-12 01:22:10
Dear All, I have a problem with the concatenation of BB variables as follows, SETBB A VARIABLE1 SETBB B VARIABLE2 SETBB C (CONC %A% '_' %B) (I want to create VARIABLE1_VARIABLE2, say some name, as the C value) This gives me "segmentation fault". How should I get around this problem? Any help is greatly appreaciated. Januka.
Sonia Castro Alarcon
2008-04-04 21:39:38
Hi, I'm trying to fully understand the header of sac files. In at the Dta Recovery section they said the header is where yyyy is the year, ddd is the Julian day, is the time of day of the start of the first record, SSSSS is the station name, and CCC is the component name for the particular seismogram being recovered, BUT I found that there are data missing: two letters before the station name whi… [more]
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Xuefeng Shang
2008-04-01 19:58:06 - 2008-04-02 18:24:19
Hi all, When I used sac to remove the instrument response, I got such error below: *** glibc detected *** /quake/linuxlocal/sac_v100/bin/sac: double free or corruption (!prev): 0x086e50e8 *** ======= Backtrace: ========= /lib/[0x92adf1] /lib/[0x92e430] /quake/linuxlocal/sac_v100/bin/sac[0x80581ef] /quake/linuxlocal/sac_v100/bin/sac[0x80aef62] /quake/linuxlocal/sac_v100/bin/sac[0x80ae65e] /quake/linuxlocal/sac_v100/bin/sac[0x8055080] /quake/linuxlocal/sac_v100/b… [more]
16:09:59 v.ad6b513c