三维方位各向异性介质数值模拟及波场分析

采用交错网格技术将速度-应力方程中的速度对时间的导数转化为应力对空间的导数, 将弹性波动方程表示为与二阶双曲方程等价的一阶应力-速度公式, 以实现三维三分量地震波场模拟。对获得的波场快照、VSP记录图像和地面记录图像进行波场分析, 发现在波场图像中存在明显的拟P波、拟快横波和慢横波, 还出现了横波分裂、横波分裂盲区及波面三分叉等地震波在方位各向异性介质传播时产生的特殊现象。研究结果表明, 用交错网格三维模拟方法研究方位各向异性介质对方位各向异性介质中地震波传播反演能起到很强的辅助作用。

Numerical simulation and wave field analysis of 3-D azimuthal anisotropy media

Used the staggered grid techniques to translate the velocity derivative with respect to time into stress derivative of spatial in velocity-stress equation, and expressed the elastic wave equation in first-order velocity-stress equation equial to second-order hyperbolic equation, the simulation for the three dimensional tricomponent of seismic wave field is achieved. The analysis of wave field snap shoot, VSP image recording and ground image recording indicates that the obvious quasi-P, quasi-SV and quasi-SH, and even some particular phenomena produced in azimuthal anisotropic medium propagating of earthquake wave such as shear-wave splitting, shear-wave splitting dead zone and wave-front three bifurcation exist in wave field image. The results show that three dimensional simulation of staggered grid technique is an important comp lement for study of the inversion of azimuthal of anisotropic medium to earthquake wave propagation in azimuthal anisotropic medium.