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
Hi
I agree with the previous posts, in particular you should be picking the maximum value maybe sumax can help with this. I also recommend you resample at a higher sample frequency - suggest suresamp rf=4, if you want to get a better estimate of the peak times.
Richard
On 05/08/2020 20:21, Erdi Apatay wrote:
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
Seisunix mailing list Seisunix@mailman.seismic-unix.org https://mailman.seismic-unix.org/listinfo/seisunix
Erdi,
It looks like you have a zero phase wavelet in your signals. The place to pick first arrivals is the black maximum. Your arrow is on a side lobe. Zero phase wavelets can be the result of correlation, like with a Vibroseis source. Also, they can be a wavelet of choice in some programs that compute synthetic data. If your data are synthetic, look into using a minimum phase wavelet, if it is available.
Paul
Dr. Paul Michaels, PE Professor Emeritus, Engineering Geophysics http://173.255.241.228 https://www.boisestate.edu/earth/people/paul-michaels/
On 8/5/20 1:21 PM, Erdi Apatay wrote:
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
Seisunix mailing list Seisunix@mailman.seismic-unix.org https://mailman.seismic-unix.org/listinfo/seisunix
seisunix@mailman.seismic-unix.org
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Erdi Apatay -
paulmichaels -
r.w.hobbs