A 3-D FINITE DIFFERENCE METHOD USING IRREGULAR CRIDS FOR ELASTIC WAVE PROPAGATION IN ANISOTROPIC MEDIA
各向异性介质弹性波传播的三维不规则网格有限差分方法

This paper presents a new 3D finite-difference (FD) method using spatially irregular grids to simulate elastic wave propagation in heterogeneous anisotropic media with topographic structures. The method approximates the first-order elastic wave equations by the finite difference operators on irregular grids with second-order time precise and fourth-order spatial precise. Unlike the multi-grid scheme, this method has no interpolation between the fine and coarse grids. All grids are computed at the same spatial iteration. Complicated geometrical structures like rough submarine interfaces, faults and nonplanar interfaces are treated with fine irregular grids. Theoretical analysis and numerical simulations show that this method saves considerable memory and computing time, at the same time, has satisfactory stability and accuracy. The proposed scheme is more efficient than conventional methods in simulating seismic wave propagation in complex topographic structures.