Search found 525 matches

by admin
Wed Sep 26, 2007 11:12 pm
Forum: Developer's corner
Topic: Computation of theoretical dispersion curves
Replies: 0
Views: 8098

Computation of theoretical dispersion curves

The core algorithms used for the computation of dispersion curves are located in dynamic library qtbwave . The structure of these algorithms is described in detail in my PhD available at http://marc.geopsy.org/publications.html . The API for computing dispersion curves is rather simple. An example c...
by admin
Wed Sep 26, 2007 9:49 am
Forum: Dinver usage
Topic: use of refference ground model
Replies: 1
Views: 5063

1) What do you mean by the reference ground model ? Inversion of dispersion curves and autocorrelation curves are exactly the same from the point of view of the parameterization. They differ only in the misfit computation. 2) For dispersion curves, if you want to load a target file, go to menu File/...
by admin
Mon Sep 24, 2007 3:12 pm
Forum: Geopsy usage
Topic: Sac import bugs
Replies: 5
Views: 8139

Mixing up between Little and Big endian for SAC files is now fixed (for next release). In fact, it was linked to the Preference and Load format dialog boxes and other file format may be affected (SEGY,...). Because "Automatic recognition" does a good job in general, I never test these two other ways...
by admin
Mon Sep 24, 2007 2:26 pm
Forum: Geopsy usage
Topic: Sac import bugs
Replies: 5
Views: 8139

Sorry, I edited your message to remove clear text email address (spam robots like them so much).
by admin
Mon Sep 24, 2007 7:40 am
Forum: Geopsy usage
Topic: Sac import bugs
Replies: 5
Views: 8139

1) What is the error message displayed when you load SAC files? When trying to load a big endian SAC file with little endian forced, you can get this message in the log window: Loading SAC : Geopsy can only open SAC files with version 6 Actual version is 100663296. It may lead to instabilities. Load...
by admin
Sun Sep 23, 2007 8:47 pm
Forum: Dinver usage
Topic: Ellipticity inversion
Replies: 2
Views: 6017

Be careful that ellipticity inversion is correct only if your ellipticity curve is effectively the Rayleigh ellipticity. DO NOT TAKE the H/V ratio as the ellipticity, you may found any kind of results, quite different that the real profile. This option in Dinver has been added in parallel to recent ...
by admin
Fri Sep 21, 2007 4:21 pm
Forum: Dinver usage
Topic: poisson's ratio
Replies: 1
Views: 4912

Currently the Poisson's ratio implementation does not work if it is completely fixed. It might be something to implement in the future: when Poisson's ratio is fixed, all Vp parameters must be removed for the inversion itself. In fact, if Poisson's ratio is fixed, Vp is directly computed from Vs. An...
by admin
Fri Sep 21, 2007 3:55 pm
Forum: Dinver usage
Topic: Inverting SPAC curves
Replies: 10
Views: 16431

Hi Elham, 1) Are you running inversion of spac curves? Did you select them with spac2disp before? The cause might be that your parameterization is too restrictive? It would be helpful to be able to attach images (for instance showing your Vs profiles) to this discussion. I'll try to add a modificati...
by admin
Thu Sep 20, 2007 12:32 pm
Forum: Geopsy usage
Topic: max file
Replies: 1
Views: 5175

.max files produced by FK and other tools can be analyzed by max2curve. The other tools that produce .max files are the SPAC and HV TFA. max2curve takes values as input (samples from the statistical point of view) measured for each frequency band and builds a normalized histogram for each frequency....
by admin
Thu Sep 20, 2007 9:50 am
Forum: Geopsy usage
Topic: H/V windowing
Replies: 3
Views: 5791

Ok, I'll fix the problem you reported in your first message and I'll keep this option available.
by admin
Thu Sep 20, 2007 9:29 am
Forum: Geopsy usage
Topic: H/V windowing
Replies: 3
Views: 5791

I wondered if this option was still necessary. The "At least" was first introduced by Gaillot and Bertrand in their original code in Fortran. At that time the fft computation was limited to power of 2 number of samples. Rather than systematically adding zeros at the end of a fixed length time window...
by admin
Thu Sep 20, 2007 8:41 am
Forum: Geopsy usage
Topic: H/V ratio => N/V and E/V
Replies: 3
Views: 6444

This is true, I removed the automatic output of the N/V and of E/V. It was mainly guided by practical issues. I would like to have a less messy desktop when computing H/V. In most situations, just H/V (with a good average of both horizontal components) is sufficient. For other special cases where yo...
by admin
Wed Sep 19, 2007 4:04 pm
Forum: Geopsy usage
Topic: DC removal
Replies: 3
Views: 5758

For the processing signals without any particular pre-selection of time windows, it is of course useless. If you want to reject time windows with STA/LTA criteria, it is the same, the average value of the global signal has no influence. So in any case, doing such processing is useless. If your data ...
by admin
Wed Sep 19, 2007 3:58 pm
Forum: Geopsy usage
Topic: Fourier amplitude spectra
Replies: 4
Views: 6517

This is now implemented for the next release, for spectrum toolbox the exported names are, for instance: S01A_E.spec S01A_N.spec S01A_Z.spec S01A_E.log S01A_N.log S01A_Z.log The bug I encountered while exporting was due to the fact that my spectra had no maximum at all. This is now fixed. For all ot...
by admin
Wed Sep 19, 2007 3:39 pm
Forum: Geopsy usage
Topic: DC removal
Replies: 3
Views: 5758

For H/V and for all array processing the mean is removed on a time window basis. So no need for further implementations. For spectra (H/V and spectrum tools), the time windows are processed this way: psig->suppressDC( true, 0 ); if ( specParam->doTaper() ) { double winLen = tw.lengthSeconds(); psig-...