[CIG-SEISMO] Problems in seismograms - Specfem3D

[AZZOLA Jerome (JDS)]

Hello,

First, I would like to thank CIG Seismology for providing Specfem3D Cartesian and other very useful Software with free access.
I was working with Specfem2D to simulate propagation of waves in a plate with holes that I mesh using the external mesher GMSH. I would like now to model the same problem using Specfem3D. For my convenience, I have to use GMSH to mesh the propagation medium, which is still a perforated plate. I join my data files and an output. I would like to propose you the link above to have a closer look to the geometry and the mesh files I use also:
https://drive.google.com/open?id=0BzMCuLE_smWxR001V1lZbFM4Y2s
The problem is that the seismograms that I obtain show wiggles that I relate to computational instability. If I use a higher sampling rate, the hysteresis is even increased. I don't understand the origin of the problem. It seems that the mesh has no influence because the increase of the number of elements is not a solution. I have the same problem when I simulate the propagation in a plate without holes. I checked the stability coefficient for wave velocity in the output files and the skewness of my elements. Do you have any idea about the origin of this instability ? Cordially,

--
Jérôme AZZOLA
Doctorant en géosciences
Tél : +33 (0)7 68 54 92 57
azzola at unistra.fr
jerome.azzola at gmail.com

EOST - Ecole et Observatoire des Sciences de la Terre
5, rue René Descartes
F - 67000 Strasbourg
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