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 November 2007

Arthur Snoke
2007-11-29 15:49:44 - 2007-11-29 19:28:21
I used the wrong address for the sac-help listserv. ---------- Forwarded message ---------- Date: Wed, 28 Nov 2007 22:49:36 -0500 (EST) From: Arthur Snoke <> To: Tim Ahern <>, Brian Savage <>, Robert B. Herrmann <> Cc: Subject: Re: [SAC-HELP] doubles in sac Tim and others, Bob touched on what I think is the biggest problem in modifying sac: the header is fixed in length so one could not… [more]
Tim Ahern
2007-11-28 19:41:39 - 2007-11-29 15:40:59
Greetings We have a question for the SAC users group. Recently a need to support double precision floating point for data in SEED format has been identified. While SEED itself can support this, the problem comes with possible output formats the rdseed program should support. The most widely used format is SAC format in our estimation. Our question is, is it possible for SAC to support double precision floating point values without loosing precision? Would it be extremely difficul… [more]
Robert Herrmann
2007-11-28 22:51:09 wrote: Tim: I do not know if this response will get back to the mailing list - so you get a copy If the data stream should be modified to have doubles for the data, we should also consider doubles for the SAC float header values - One CANNOT pick time correctly at 23:59:59 for 200 Hz data sets (I know this is extreme) is the continuous data stream starts at 00:00:00 - the seven digit accuracy of floating point is exceeded One would just need to red… [more]
No replies
Alejandro Gallego
2007-11-16 20:04:54
Hi everybody I want to change the background color of my figures. I am using this command COLOR RED INCREMENT OFF SKELETON WHITE BACKGROUND BLACK LIST STANDARD All the features change the color except the Background, anybody knows how to fix this problem. Thanks Alejandro
No replies
2007-11-15 03:18:16
Dear all, I agree with Apostolos Agalos. I also think the Constant should be derived from the multiplication of the Sensitivity with A0. I think the following method should be right when calculating the CONSTANT. CONSTANT=A0×Sensor Sesivity × Digitiser Gain × 2*pi here A0 is in rad/sec Unit,Digitiser Gain is V/ms.
2007-11-15 02:27:55
I am running Sac v101.1 on a Mac PPC G4 with OSX v10.4.10. Does anyone know if the sac command 'mat' works on Macintosh computers (with Sac v101.1 Mac PPC OSX version), and if so, could you send me an example of using it? This is what I got when I tried to run it. First I read in some seismograms, then SAC> mat testmat1.mat SACdata SeisData Mfile specified is: testmat1.mat ERROR 8002: Cannot link to MATLAB shared object: or if I try a more interactive approach SAC> mat ERROR 8002: Cann… [more]
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Mohamed elgabry
2007-11-14 21:44:35
i agree with Fang lihua and I strongly recommend you to read the book Of Poles and Zeros: Fundamentals of Digital Seismology by F. Scherbaum ________________________________ From: on behalf of FANG Lihua Sent: Wed 11/14/2007 12:18 PM To: Subject: [SAC-HELP] ??:sac-help Digest, Vol 29, Issue 1 Dear all, I agree with Apostolos Agalos. I also think the Constant should be derived from the multiplication of the Sensitivity w… [more]
No replies
2007-11-14 20:56:22
I am not completely sure that this is the solution for you but it is common to set as Constant the result from the multiplication of the Sensitivity with A0. try it!!
No replies
2007-11-14 02:11:06 - 2007-11-14 17:09:24
Hi, I use SAC to remove the instrument response, SAC>transfer from polezoro subtype response.pz to none freqlimits 0.01 0.02 5.0 8.0 the following is the content of response.pz ******************************* POLES 5 -0.03701+0.03701 -0.03701-0.03701 -1131.00.0000 -1005.00.0000 -502.70.0000 ZEROS 2 0.00000.0000 0.00000.0000 CONSTANT ???? ******************************* But I don't know how to calculate the constant. I got the calibration sheet from Gurapl. The normalization f… [more]
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