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Dear Marc, and all.

Hello.
I'm using dinver for Rayleigh wave dispersion inversion.

My target sites seem to have very fast Vs half space layer >~3000 m/s at ~500m.

For the first time, I set the velocity range of the half space to have 50-4000 m/s, as the other layers for a broad search.
But no result model has a layer that exceeds ~3100m/s (approximately, it could be more or less).
So I tested the velocity range of the half space to be like 3100 - 5000 m/s.
Then it generates the following error message,
"ASSERT: "parameterSpace.isOkDebug()" in file src/Generator.cpp, line 132"

I guess it is because the parameter space of velocity is limited up to ~3100 m/s.
I'm using Geopsy version 3.4.2
Could you give me some comments on this issue????

Always thanks for your efforts.

Best regards,
Youngjun Jeon

Hi Youngjun,

I checked with 3.5.0-preview and I did not encounter this ASSERT. It happens with gradient layers due to an unsolved bug.

Why are you using so many layers? With 3 layers in the soft part and 2 below 15 m, I got a reasonable fit of the high frequency part. In any case, the low frequency part looks difficult to fit. A contrast around 25 m is inverted. Your dispersion curve has a big gap between 2.53 and 7.88 Hz. In general, it is safer to have a continuous sampling to avoid mode jumping during forward computation. It does not occur here, I test a resampled version of your dispersion curve and the original, I got approximately the same results. See figures.

Dear Mark,

Thanks for your fast comment!

In terms of the number of layer, I'm using multiple layers larger like ~15 layers then it generally accepted for the first trial inversion process.
Then I reduce the layer number based on the visually constrained layers.

Best,
Youngjun Jeon

Usually, the approach is reversed: start with few and increase until getting an acceptable fit, and thirdly start an appraisal phase (depth limits, non-uniqueness,...)