Best software for seismic refraction tomography

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Preston09
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Best software for seismic refraction tomography

Post by Preston09 » Fri Oct 26, 2012 8:53 pm

I am using SeisImager, but it crashes very often. Any recommendations? Thanks!

kaminae
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Re: Best software for seismic refraction tomography

Post by kaminae » Sun Oct 28, 2012 7:32 am

I use zondst2d software. We can compare results of two softwares if You have files with picked times.

lealoekio
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Re: Best software for seismic refraction tomography

Post by lealoekio » Sun Oct 28, 2012 8:45 am

I heard SeisOpt® @2D™ is very good:
http://www.optimsoftware.com/products/seisopt-2d/

kaminae
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Re: Best software for seismic refraction tomography

Post by kaminae » Sun Oct 28, 2012 8:59 am

To make the right choice - we have to check all the software on a same profile. The results can be published in this topic.
I have some good profiles for comparison.

Preston09
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Re: Best software for seismic refraction tomography

Post by Preston09 » Sun Oct 28, 2012 9:49 pm

I like SeisOpt -> requires no prior assumptions of subsurface structure, or any other subjective data, as input.

kaminae
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Re: Best software for seismic refraction tomography

Post by kaminae » Mon Oct 29, 2012 11:31 am

Is it good? I think SeisOpt used 1D inversion result at first iteration(You don't see it). Starting from halfspace is impossible for refraction inversion.
At some case ivery important to use a prior model.

Preston09
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Re: Best software for seismic refraction tomography

Post by Preston09 » Mon Oct 29, 2012 3:29 pm

I don't know yet. I only read the introduction and it seems to be more robust than SeisImager.

kaminae
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Re: Best software for seismic refraction tomography

Post by kaminae » Thu Nov 01, 2012 11:11 am

Do You have this software to test it with my specific data?

Preston09
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Re: Best software for seismic refraction tomography

Post by Preston09 » Thu Nov 01, 2012 1:41 pm

unfortunately, I don't have it.

InspecteurColombin
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Re: Best software for seismic refraction tomography

Post by InspecteurColombin » Sat Nov 10, 2012 12:08 pm

Hello all,
I am new on this forum and it happens that i have a licence of seisopt@2d. I would be very interested in comparing various inversion algorithms (which also means i do agree to carry out an inversion with seisopt). From my own experience (seisopt@2d and another academic code based on the SIRT technique), the best final image has not always been provided by seisopt. But it remains a very good code which i really like to use.
I confirm that no a priori information is needed to carry on the inversion process. It is however possible to set velocity ranges from travel-time curves analysis. Nevertheless, varying grid sizes have to be tested for each dataset and the code is eventually time-consuming. Batch processing is very much appreciated for this, since it is possible to run the code during the night. The processing time also depends on the chosen resolution (grid cell size) as well as on the number of geophones & shots, but this last point is not a very original information :D.

lealoekio
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Re: Best software for seismic refraction tomography

Post by lealoekio » Sat Nov 10, 2012 9:28 pm

There is a sample data set at: http://terra.rice.edu/department/facult ... ageep2011/
Apparently it's a big file, but it would be interesting to the inversion results at least using portions/sections of the data set.

InspecteurColombin
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Re: Best software for seismic refraction tomography

Post by InspecteurColombin » Sun Nov 11, 2012 5:13 am

It appears to be a large very large dataset with up to 10000 picks, which might not be relevant of an "everyday" refraction survey. As you said, we can either use portions of this dataset (1 geophone over 2 and 1 shot over 3, for example) or generate or own synthetic dataset (24 geophones, 2 to 3 layers with varying depths and shapes, etc.).
Since i am on a sick leave with plenty of free time, I can do that and/or sort the sageep dataset. Synthetics have the advantage to be noise and/or human error free and will provide a good estimate of the efficiency of the code, whereas real data will offer a comparison of the robustness of the algorithm to reconstruct the ground structure with picks which may be not perfect.
Otherwise we might use Kaminae's data since he seems to have good profiles.

Preston09
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Re: Best software for seismic refraction tomography

Post by Preston09 » Sun Nov 11, 2012 12:17 pm

Sounds like a plan. I will use the sageep data, probably a section in the beginning of the data to test SeisImage2D as soon as I got time.

kaminae
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Re: Best software for seismic refraction tomography

Post by kaminae » Mon Nov 12, 2012 11:42 am

There are inversion result's with zondst2d.
No apriori information. 5 iterations. Time of calculation 7 min.
Attachments
st.png

kaminae
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Re: Best software for seismic refraction tomography

Post by kaminae » Mon Nov 12, 2012 12:06 pm

Small synthetic data set
Attachments
data.txt
Synthetic data (sx rx time)
(11.52 KiB) Downloaded 575 times
res.png
Inversion result for synthetic data(Zondst2d).
modl.png
Model for testing

InspecteurColombin
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Re: Best software for seismic refraction tomography

Post by InspecteurColombin » Mon Nov 12, 2012 1:28 pm

kaminae wrote:There are inversion result's with zondst2d.
No apriori information. 5 iterations. Time of calculation 7 min.
I guess it's the result of the inversion of the SAGEEP data set. It is really impressive! Which parameters didi you use (grid cell size for instance) and what is the final RMS error?
On my own, and since I do not have the seisopt@pro licence, I cannot process data with more than 28 shots, i gave up with the sageep data set.
At least, this is an information about which software is the best to invert huge data set between Zond & Seisopt.

I produced a synthetic model as well but I will invert the data you just provided.

kaminae
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Re: Best software for seismic refraction tomography

Post by kaminae » Mon Nov 12, 2012 1:52 pm

Yes, it's SAGEEP data. As You can see - it is some problem with determination of thin inclined layer. (Which deal with to resolution of refraction tomography).
RMS ~ 1.3% (You can see it in the status bar of program windows). I can use irregular Z and X grid because special forward modeling algorithm is used.
~ 20000 cells for FM and ~3000 for inversion.

Put here Your data set to invert it.

kaminae
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Re: Best software for seismic refraction tomography

Post by kaminae » Mon Nov 12, 2012 2:18 pm

Layered inversion result
Attachments
resl.png

InspecteurColombin
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Re: Best software for seismic refraction tomography

Post by InspecteurColombin » Mon Nov 12, 2012 2:37 pm

OK.
Here is the synthetic model I generated. The details (Vp and Vs) are provided in the image. The 2nd layer stands for a water table (varying Vp but same Vs). There are 9 sources along a 115 m-long profile with 24 geophones spread each 5 m.
seismic3layers_fault.png
3layers.txt
(2.54 KiB) Downloaded 531 times
Following are the results obtained with Seisopt@2d with no a priori information. The grid geometry is 64*44 cells with vertical and horizontal dimensions of 1.8*0.9 m, respectively. The calculation took 25 mn (but I am running the code under windows virtual PC mode which may slow the process down) and I tested 10 configurations (varying number of vertical cells) for a total calculation time of about 3 hours.
The final error, in the RMS sense, is 2%.
velocity.PNG
One can see that there seem to be a poor lateral continuity around the step. This might come from 1) the seismic substratum is reached and no ray pass below and/or 2) the code produces images with gradients, which is not the case of the model.
Finally, the following provides a hitcount image. It stands for the number of times a cell has been used for the calculation. It mimics a ray-tracing and allows to see where the model is reliable or not.
hits.PNG
Since I am not a specialist of inversion, I think it is possible to enhance the results. These images are to be seen as the results of an inversion conducted by the user of a commercial code.

kaminae
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Re: Best software for seismic refraction tomography

Post by kaminae » Mon Nov 12, 2012 3:20 pm

Results for Your data set.
1. Hodographs.
2. Velocity model.
3. DOI map. Depth of investigation (robustness of result) min is good, max is bad.
4. Model quality. Parameter deal with rays coverage.
5.Layered invesion results.

time of inversion 20 sec!
Little difference between our result as I think deal with different forward solver. As You can see I use smooth velocity model (I have very smooth rays).
Attachments
allres.png

kaminae
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Re: Best software for seismic refraction tomography

Post by kaminae » Mon Nov 12, 2012 3:33 pm

This video demonstrate - how I got result
http://narod.ru/disk/63629785001.1b1916 ... s.zip.html

InspecteurColombin
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Re: Best software for seismic refraction tomography

Post by InspecteurColombin » Mon Nov 12, 2012 6:15 pm

Your data inverted with a SIRT algorithm.
grid: 48*13 cells of 2*2m (1*1 m for the forward computation).
a priori information: homogeneous velocity of 3000 m/s through the whole grid.
9 iterations, 20 s to compute and a final RMS error of 6%.
Interfaces are smoother than yours but it ain't that bad.
With rays:
modelfinal_ite09_rms2.02_modeldeparthomogene3000.PNG
Same data with a grid cell size of 1*1 m (and 0.5*0.5 m for the forward computation). 15 iterations, less than 60s for the calculation and a final RMS error of 1.8% :
velocity_1m.PNG
Results of the same data processed with seisopt tomorrow (batch processing during the night...).

kaminae
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Re: Best software for seismic refraction tomography

Post by kaminae » Mon Nov 12, 2012 6:54 pm

I found some errors in Your synthetic data.
I have modeled right part of section analiticaly for last source. It's simple 1D solution.
And I found big divergence and one strange point. It's similar to addition boundary.
I think may be three cause of error
1. You calculated data for smooth model(and we don't know - how smoothness assigned to model)
2. Model at the picture not corresponded model for calculation.
3. Software error in forward modeling(mesh, or special conditions)
Attachments
error.png

InspecteurColombin
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Re: Best software for seismic refraction tomography

Post by InspecteurColombin » Tue Nov 13, 2012 5:07 am

You're totally right. I did not check the data... My bad :oops:
The error comes from a too large delta x for the forward computation.
Here are the corrected data and I think they are fine.
seismic3layers_fault.txt
(2.66 KiB) Downloaded 545 times

kaminae
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Re: Best software for seismic refraction tomography

Post by kaminae » Tue Nov 13, 2012 8:20 am

Ok! It's correct data.
There are results for new file.
Attachments
newres.png

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