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 September 2016

George Helffrich
2016-09-26 17:35:01
Dear All - I maintain that the COSINE taper is calculated correctly (specifically, by using the sin() function). For justification of this assertion, please refer to the paper, Harris, F. J. (1978). On the use of windows for harmonic analysis with the discrete Fourier transform. Proc. IEEE 66(1), 51-83. It deals explicily with the cosine taper, and presents the time-domain coefficients w(n) (n.b. not W(n)) for it. They are calculated through the sin() function, the reason for sin() being… [more]
Peter Schmidt
2016-09-23 17:36:06 - 2016-09-24 04:57:30
Hi All Just a small note that perhaps would be reasonable to edit in the SAC manual According to manual (V101.6a, November 21, 2013) "TAPER TYPE COSINE WIDTH v" will apply a symmetric taper on format: 1-COS(...) to each end of the data. However after getting some inconsistent results I had a look in the source code and found out that the applied taper is really: ABS(SIN(...)). Perhaps a future edit of the manual could properly state this. regP -- ************************************… [more]
Peter Schmidt
2016-09-23 17:16:00
Hi all I'm hoping that someone can shed some light upon the the usage of the nerr parameter in the rsac...() function Reading the SAC manual, section :"SAC Reading and Writing Routines", I got the impression that this parameter could be used to check the success/failure to read a file (0 - success, else failure), yet when I try to read a non-valid SAC file (i.e. which should fail) nerr is 0 upon return, which later in my code causes an annoying segmentation fault as I have no other way … [more]
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Geo .
2016-09-22 18:58:58 - 2016-09-22 19:24:16
Hi, I have the following macro embedded in a shell script, and when I run the shell script, SAC does not "see" the PAUSE command and the lines below it, i.e macro is not paused and QUIT is not executed. I have a feeling that this is a bug. Am I correct? I am using SAC 101.6 sac<<END R $sacfile R MORE $synfile COLOR ON INC L BLUE RED P2 PAUSE PERIOD OFF QUIT END ERROR MESSAGE: SAC Error: EOF/Quit SAC executed from a script: quit command missing Please add a quit to the script to avoi… [more]
2016-09-22 00:12:25 - 2016-09-22 03:17:14
Hi, I want to use root mean square envelope by ENVELOPE command. I could not find any description about RMS. Anyone can help me please? Reza
Roberto Cabieces Diaz
2016-09-21 18:42:43
Hello, Now I'm developing a program in matlab to deal with deconvolution, I mean to remove the response of the instrument usin the file sac poles&zeros. By using GISMO, I bring the data to matlab but I would like to know if there would be the posibility to acces to the code of sac that make the deconvolution and translate to matlab. Thank your for your help Master
No replies
James Neely
2016-09-20 21:38:47 - 2016-09-21 18:03:23
Hi, I'm running into a problem with nested variables in an IF statement. I want to check the sampling rate of the many SAC files and then perform an action based on whether that rate is above or below a reference value. I'm trying to use a DO loop to cycle through the files. However, when I call the macro variable $i inside the header variable, I get an error that it $i is an illegal file name. It looks like SAC is not reading the macro variable correctly. Any ideas on how I can get it to read… [more]
2016-09-13 23:07:44 - 2016-09-14 15:34:12
To whom it may concern: I just downloaded SAC and SACPZ file from IRIS Wilber. What I want is ground motion velocity during earthquake times, So I run the following: r sacfilename rmean taper transfer from polezero subtype PZfile to vel freqlimits 0.001 0.002 40 50 My question is: Is the result unit m/s? How should I determine the freqlimits? In the further step, I am also going to do a band passing for the velocity time series. All the best! Kejie
08:42:19 v.ad6b513c