关键词: 各向异性介质, 弹性波方程, 频率-空间域, 有限差分, 数值模拟

Abstract: The VTI media is caused by fine periodic thin layers, and it is one of most sedimentary rocks researched by geophysicists. In dipping thin layers, the symmetry axis of VTI media should be tilted by dip angle in observing reference system, and in this case, VTI media is named transversely isotropic media with tilted symmetry axis (TTI media). In the paper, in order to overcome the numerical dispersion, we have adopted a 25-points finite difference numerical simulation scheme and derived frequency-space domain elastic wave equations of TTI media. We make use of elastic wave equation in perfect matched layer to attenuate reflection of elastic wave at artificial boundary, and get optimized coefficients on the basis of optimization theory. Finally, we successfully implement numerical simulation of seismic elastic wave field in TTI media with concentrating force source. The results of seismic wave simulation illustrate that elastic wave fields of anisotropic media are very complex, transverse waves often have phenomena of singularity, and the difficulties of surface seismic record processing increase owing to TTI media.

Key words: anisotropic media, elastic wave equation, frequency-space domain, finite difference, numerical simulation