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| Finite difference method of irregular grid for elastic wave equation in heterogeneous media |
| Revised:August 20, 2002 |
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| DOI：10.7511/jslx20042026 |
| KeyWord:finite difference method,irregular grid,heterogeneous anisotropic media |
| Sun Weitao~ |
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| Abstract: |
| This paper presents a new finite-difference (FD) method for spatiall irregular grids to simulate elastic wave propagation in heterogeneous anisotropic media. It is very simple and costs less computing time. Complicated geometrical structures such as low-velocity thin layers, cased borehole and nonplanar interfaces are treated on a fine irregular grid. Unlike multi-grid scheme, this method has no interpolation between the fine and coarse grid and all grids are computed at the same spatial iteration. Models with complex geometrical interfaces, including underground lens structure and cased borehole, are treated in a way similar to regular grid points but with different elastic parameters and density. The Higdon's absorbing boundary condition is adopted to eliminate boundary reflections. Numerical simulations show that this method has satisfactory stability and accuracy. It is more efficient in simulating wave propagation in heterogeneous anisotropic media than conventional method using regular rectangular grid of equal accuracy. The method can be easily extended to unstructural grid and three dimensional problems. |
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