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 May 2018

Gowthami Bandlamudi
2018-05-31 18:05:28
Dear sac experts I need some help.I have three components r,t,z and sac macro mtrf file. When I am running mtrf in sac following error is coming. SAC> m mtrf file efam.syn comps r t z phase P plot yes pick maybe window 12x 3.0 tables ak125 debug no efam.syn.r efam.syn.t efam.syn.z Unexpected characters after IF: if %rt% eq tr ^ ERROR 2703: Can't evaluate logical expression: ERROR 1016: Terminating execution of macro mtrf Command line is: if %rt% eq tr I… [more]
Alessandro Todrani
2018-05-28 22:15:10 - 2018-05-31 16:39:49
Hi, sorry for the question. I'm using your SAC programm for my university thesis, and i have a problem with ERROR 124. The message that appear is: Can't change to the directory. Check your permission. How can i resolve this error? It doesn't always happen, but when i have this error i can't go on. I'm waiting your answer. Thank you so much, Best regards, Alessandro.
Mario La Rocca
2018-05-29 04:56:33 - 2018-05-31 05:25:49
dear sac experts, I have a problem with the picking of S phase in sac. I follow this procedure to save pickings: 1) r filename.*.sac 2) ohpf pickings.txt 3) ppk p 3 bell off then I type 'p' and then 'h' at the P wave arrival time, and it works fine because the pickings.txt file will contain a row in the correct format for that station (after the file has been closed by chpf). However, if I type 's' and then 'h' for the S wave arrival time, it does not work. In fact in the pickings.txt file I fi… [more]
김 용우
2018-05-31 02:31:38
R,T My sac file is BHN, BHE. CMPINC=90 and CMPAZ=0 in BHN channel.CMPINC=90 and CMPAZ=90 in BHE channel. I know that CMPAZ and CMPINC is required for conducting Rotation, but My sac files not included information of CMPAZ and CMPINC. 1. Is it possible that rotate in sac without CMPAZ and CMPINC? 2. If not, how to obtain CMPAZ and CMPINC? ---------------------Yong-woo KIMEmail : studentDivision of Geology and GeophysicsKangwon National University1 Gangwondaehak… [more]
Mukesh Das
2018-05-28 17:05:47 - 2018-05-28 22:04:18
Dear SAC users, I have two questions: 1) I want my plot without any text written on it. There should just be the plot of my data (nothing else). How should I do that? 2) I am using "p2" command for plotting two waveforms in SAC. But, I want them to be plotted in different colors. Also, I want to make "linewidth" of one waveform thicker than the other. I would be greatful if you can help me with this. Thank you very much. Regards, Mukesh Kumar Das JRF (Research Scholar) Department of Applie… [more]
Mar Tapia
2018-05-10 21:17:22 - 2018-05-18 07:28:50
Hi, I have some questions related to spectrogram function in sac: 1. How can I save the results from spectrogram function in order to plot with other softwares? 2. And is it possible to control the colorbar values in some way? 3. I don't understand why the spectogram plot using PSD method is so different from the spectrogram function in matlab using same window length. Is there any smooth or ponderation in the final results in order to show better singularities or important zones? Thanks i… [more]
Mukesh Das
2018-05-15 18:22:35 - 2018-05-15 23:12:02
Dear SAC Users, I have some sac files where T0MARKER and T1MARKERS are set corresponding to P-and S-wave arrival times. But, when I plot my seismograms it does not show "P" and "S" corresponding to their arrival marks; instead it shows "t0" and "t1". or, when I list my headers, it shows like this: T0MARKER = 239.23 T1MARKER = 456.45 but I want it to be like this: TOMARKER = 239.23 (P) T1MARKER = 456.45 (S) How to change this. Your help in this regard will greatly be appreciated. Rega… [more]
Nima Dolatabadi
2018-05-06 16:22:53
How can I set origin time for my data files in .SAC format in its header? I believe OMARKER is what I'm looking for. But the problem is how to evaluate it. This really is neccesary and I need it. Glad If you would mind helping me. Kind Regards.
No replies
George Helffrich
2018-05-06 04:26:11
Dear All - Here’s a set of tested solutions to the earlier question about cutting a monthly SAC data file into daily files. It corrects flaws in the earlier solutions and tidies up the resulting file headers. Test data: copy this into a file, say “generate”, then invoke it as a SAC macro. funcgen line (1 / 86400) 0 npts 86400 delta 1; w /tmp/day ;* 1 day do i = 1 , 31 merge checktimes off /tmp/day ;* append enddo ch nzyear 2000 nzjday 1 nzhour 00 nzmin… [more]
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Mary Muthoni
2018-05-02 19:33:13 - 2018-05-03 07:55:03
Dear Sir/Madam, How do I subdivide a continuous monthly data into days using SAC? Thanks. Mary
  • Re: SAC - George Helffrich - 2018-05-03 07:55:03
Sachin Tiwari
2018-05-02 22:09:22 - 2018-05-03 02:24:40
Dear Friends, I am looking for your help very urgently. I have a time series with trace length ranging from -10 seconds to 50 seconds. I need to find the maximum amplitude value and its index between -5 seconds to 3 seconds. Please let me know how to perform this operation in SAC. Your help in this regards will highly be appreciated. Regards, -- *Sachin Kumar * *Junior Research Fellow (JRF)* *Dept. of Applied Geophysics* *Indian Institute of Technology (Indian School of Mines), Dhanbad* *J… [more]
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