[CIG-SEISMO] Use of SPECFEM3D and meshfem3D for tomography

[Sergey Tikhotsky]

Dear Piere, dear Dimitri, dear all!

I'm going to use the SPECFEM3D code for the purposes of seismic 
tomography at regional to local scales, including Frechet kernels 
computation and waveform inversion. I have downloaded the latest svn 
version of SPECFEM3D_SESAME and brought it to work but still have some 
questions.

1. The manual (version from august, 2010) clearly doesn't correspond to 
the actual state of the mesher meshfem3D. Thanks to your comments in 
mailing list I generally recognised the way it works, but could you 
please provide some further comments regarding the use of the new 
Par_file, particulary the relation between the "interfaces" and 
"regions" with different "materials". It looks like the borders of the 
rectangular regions may cross the interfaces. Is it correct and how it 
will be interpreted by the mesher?

2. The "Tomography model" example is based on the use of CUBIT. I don't 
have the ability to use CUBIT right now. So the first question is: "Is 
the use of CUBIT essential for the preparation of these "tomography" 
type of mesh (i.e., based on gradient or some other smooth distribution 
of properties) or the same functionality may be provided by specfem3D?". 
And if specfem3D may be used for this purpose, please give some tips on 
how it can be accomplished.

Thank you in advance!

Yours, Sergey.