【摘要】 针对横向各向同性(VTI)介质P-SV波和SH波一阶速度—应力波动方程,本文应用交错网格法进行了地震波场数值模拟。其模拟效果在很大程度上取决于边界条件的处理。针对特征分析法吸收边界条件存在的边界处差分精度低、吸收效果差等问题,本文采用特征分析法和扩边衰减法形成组合边界条件对人工边界进行吸收处理,较显著地削弱数值频散,提高了差分精度;同时还提出了改进的衰减函数及其应用原则,可以更好地模拟复杂介质波场传播机理。更多还原

【Abstract】 One-order P-SV and SH wave velocity-stress wave equation in transversely isotropic(VTI)medium is able to be used for numeric simulation of seismic wavefield with the aid of staggering grid method,which depends on the treatment of boundary condition to a very degree.Facing the issue that the absorption boundary condition of characteristic analysis method characterized by lower differential precision at boundary and poorer absorption effect,the paper presented using characteristic analysis method and boundary-enlarged attenuation method to form combined boundary condition to carry out absorption processing of manual boundary,which remarkably weakens numeric dispersion and improves differential precision;at the same time,the paper also presented the improved damping function and application principle,which is able to better simulate the propagation mechanism of wavefield in complex medium.更多还原