Nonstandard FDTD for Accurate Modeling of Seismic Wave Propagation in 2D
Abstract
Finite-difference method in time-domain (FDTD) is one of the most common techniques used for modeling of seismic wave propagation. The algorithm is popular because it is simple and easy to program. In the FDTD, the numerical solutions do not coincide with the theoretical solutions unless the temporal and spatial discretization are sufficiently fine due to the numerical dispersion and grid anisotropy from the FDTD schemes. In this study, we develop a FDTD scheme called nonstandard FDTD (NS-FDTD) for 2D elastic (P- SV) wave computations, which was originally proposed in computational electromagnetics (e.g. Cole, 1997, IEEE Trans. MTT). We implement the NS-FDTD through the following two steps: we first replace the spatial and temporal grid spacings by their frequency optimized counterparts called the correction functions, and we then introduce a finite-difference form of the Laplacian. The nonstandard scheme efficiently reduces numerical dispersion and grid anisotropy to improve the computational accuracy. The high accurate nonstandard versions of the FDTD algorithms are only slightly more complicated than the standard ones, so that existing computer programs could be easily modified to run the nonstandard ones.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFM.S23A1880J
- Keywords:
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- 0560 Numerical solutions (4255);
- 3285 Wave propagation (0689;
- 2487;
- 4275;
- 4455;
- 6934);
- 7200 SEISMOLOGY;
- 7290 Computational seismology