The Discontinuous Galerkin Finite Element Method and its Application to Global Wave Propagation
Abstract
We present the application of the discontinuous Galerkin (DG) method combined with a time integration scheme using Arbitrarily High-Order Derivatives (ADER) to study global wave propagation problems. Code validation is performed through comparisons with other established numerical methods. The ADER-DG approach offers geometrical flexibility through the usage of unstructured triangular or tetrahedral meshes in terms of local mesh refinement in areas of interest and mesh adaptation to complex earth models. In addition - through local time-stepping and varying polynomial order (p-adaptivity) - the computational setup can be efficiently adapted to Earth models with large velocity variations. Meshes can be designed to honour undulating topography of the Earth's surface and interior interfaces. Furthermore, the numerical scheme is high-order accurate in space and time necessary for the modelling of high frequency wavefields and long propagation distances. For this reason, the method provides a high potential for being used in accurate global wave propagation modelling and its applicability is systematically studied in this work. In particular, we present different methods of implementing material variations or material gradients of the isotropic 1D PREM velocity model investigating the trade-off between mesh spacing and approximation order. We show if the material variations or the seismic wavelength represent the limiting factor for the mesh generation process. Finally, we validate our results through comparison with those obtained by the spectral element implementation of Komatitsch and Tromp and another DG algorithm of Burstedde and Ghattas.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFM.S53F..02W
- Keywords:
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- 7290 SEISMOLOGY / Computational seismology