August 2020 - Seisunix - mailman.seismic-unix.org

VSP
by Erdi Apatay 30 Sep '20

30 Sep '20

Hello all About my Zero offset synthetic VSP data, I thought something but I am not sure about the effect of this issue. If I get rid of the first three traces from the data before picking arrivals (deleting or killing), and continuing next process steps, that give rise to any effect for results? If not so, How should I write for getting rid of these three traces? I added my screenshot (plus signs denotes picking) Thank you Best Erdi

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Zero Offset VSP help
by Erdi Apatay 26 Aug '20

26 Aug '20

Hello All I have a script I am using for Zero Offset VSP processing. First of all, my first three traces looked cut so I rejected them. After getting rejected file, I filtered out the downgoing wavefield by sudipfilt. Then, I picked arrivals on the zero amplitude line corresponding to picking amplitudes. Then, I converted those arrival times (seconds) to milliseconds and saving them in a txt.file. After that, txt file is converted from ascii to binary format. Finally, I am adding those time values to the traces by sustatic command. At this point, however, when I try to plot the flattened upgoings, the script plots just a so narrow part as follows: [image: fkfiltflat.PNG] Can you help me with this issue? I tried to change a lot of things but I could not get whole flattened upgoings. If you would like to check my script, I added here. Thank you Erdi

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New SU minor release
by Dominique ROUSSET 25 Aug '20

25 Aug '20

Hi everyone John has set up a new 44 minor release of Seismic Unix (R19). Thank you John ! It is available at https://wiki.seismic-unix.org Enjoy SU D. -- |Dominique Rousset LFCR UMR5150 / E2S UPPA / Dpt des géosciences| |Univ. Pau et des Pays de l'Adour BP 1155 F-64013 Pau Cedex - France| |mailto:dominique.rousset@univ-pau.fr jami:drousset http://lfc.univ-pau.fr| |Off: +33 559 407 423|Cell: +33 660 861 391|xmpp: dominique(a)rousset.nom.fr|

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SU Release 44R19
by John Stockwell 24 Aug '20

24 Aug '20

There are a few bug fixes. I have put in a few epidemiological modeling codes in regard to our current situation with the Coronavirus. These items may be of interest for those teaching ordinary differential equations. Also, this modeling approach could be modified for oil and gas field production modeling. John Stockwell Visit: https://wiki.Seismic-Unix.org The new home of Seismic Un*x

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Slope values in f-k filtering
by Erdi Apatay 10 Aug '20

10 Aug '20

Hello Again Can someone show me how I should assign the slope values (for example 4 values) in sudipfilt? If it is possible, showing on the screenshot, that would be great. My data ( synthetic Zero offset VSP) parameters: my first geophone's position is 1000m depth, and the last geophone's position is 3000m depth. The Geophone interval is 20 m. I added my data. (Are there any visual sources for sudipfilt or any other things that I can utilize? Thank you Erdi

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Zero Offset VSP Processing
by Erdi Apatay 09 Aug '20

09 Aug '20

Hello Everyone I said before that I was trying to do Zero Offset VSP Processing. To do that, I tried to use free software is called MVSP and Crewes toolbox. My problem is that I can start picking first break arrivals from 4th trace, and I can not see and pick the first three traces when I look at the data during the picking. The first software itself assigns negative values for the first three traces, which results in negative velocities. On the Crewes, I am trying to assign values like 0.001 0.002 0.003 before the 4th trace because the 4th trace's time is 0.006, which probably gives rise to wrong velocities. In short, Can I do anything about this issue on Seismic Unix? Is there any chance to fix it? I added one of my files and the screenshot zoomed where the problem is. I modeled and created this data on different code (fdelmodc). **The data is passive data, and I utilized the noises, recording 120s. So, when you look at my data, you need to zoom in to see closely. Thank you Best regards Erdi

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VSP Processing Bandpass filtering
by Erdi Apatay 08 Aug '20

08 Aug '20

Hello All I am trying to move step by step on Zero Offset VSP Processing. Now, I am trying to apply band pass filtering to my data using this: *sufilter < xcor_output_20_sources_B1.su f=5,10,15,20 amps=0,1,1,0 | filter_data.su <http://filter_data.su>* However, I did not understand how I should define the frequencies. I tried to leave the first two frequencies constant and changed the next two frequencies little by little. Then, I tried to subtract each other, using this: *sudiff file1.su <http://file1.su> file2.su <http://file2.su> > diff.su <http://diff.su>* Is there any effective way to choose these 4 frequencies in bandpass filtering? How should I learn my frequencies? If you would like to check, I added my file here. Thanks Best Regards Erdi

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Bandpass Filtering
by Erdi Apatay 08 Aug '20

08 Aug '20

Hello All I am trying to apply bandpass filtering but I don't understand how should I define the frequencies in my data *sufilter < xcor_output_20_sources_B1.su f=5,10,15,20 amps=0,1,1,0 | filter_data.su <http://filter_data.su/>* How can I choose right frequencies (f values) in filtering? Thank you Erdi

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VSP Processing
by Erdi Apatay 06 Aug '20

06 Aug '20

Hello All I am trying to pick first break arrivals in Zero Offset VSP on the Crewes toolbox and another software. My problem is that I start picking from 4th trace because I cannot see the first three traces when I look at my data, which results in wrong velocities. My data is passive zero-offset VSP data, utilizing ambient noise sources. I created this by using a modeling code. I added one of my data and the problem's screenshot Can I fix this on Seismic Unix?

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Zero Offset VSP Processing
by Erdi Apatay 01 Aug '20

01 Aug '20

Hello I am looking for a software for Zero Offset Processing, but all softwares are required money. I've found this mailing list. So, I can try Seismic Unix for this. However, I guess it is tough doing Zero Offset VSP processing on Seismic Unix. Still, I want to ask. Does anyone have VSP fundamental processing scripts? If so, I would be appreciated. Thank you Erdi

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Seisunix August 2020