CUBIT and seismic wave propagation based upon the Spectral-Element Method: An advanced unstructured mesher for complex 3D geological media

Unstructured hexahedral mesh generation is a critical part of the model-
ing process in the Spectral-Element Method (SEM). We present some ex-
amples of seismic wave propagation in complex geological models, automati-
cally meshed on a parallel machine based upon CUBIT (Sandia Laboratory,
cubit.sandia.gov), an advanced 3D unstructured hexahedral mesh genera-
tor that offers new opportunities for seismologist to design, assess, and improve
the quality of a mesh in terms of both geometrical and numerical accuracy.
The main goal is to provide useful tools for understanding seismic phenomena
due to surface topography and subsurface structures such as low wave-speed
sedimentary basins. Our examples cover several typical geophysical problems:
1) “layer-cake” volumes with high-resolution topography and complex solid-
solid interfaces (such as the Campi Flegrei Caldera Area in Italy), and 2)
models with an embedded sedimentary basin (such as the Taipei basin in
Taiwan or the Grenoble Valley in France).