起伏层状介质中曲线网格有限差分法与射线法波场模拟对比研究  

Comparison of seismic wavefield simulation between the curvilinear-grid finite difference method and ray method in undulated layered medium

作　　者：杨尚倍 白超英[1,2] 何雷宇 Yang Shangbei Bai Chaoying He Leiyu(） College of Geology Engineering and Geomatics, Chang＇ an University, Xi＇ an 710054, China ） Institute of Computing Geophysics, Chang＇an University, Xi＇ an 710054, China)

机构地区：[1]长安大学地质工程与测绘学院,中国西安710054 [2]长安大学计算地球物理研究所,中国西安710054

出　　处：《地震学报》2016年第6期854-868,共15页Acta Seismologica Sinica

基　　金：国家科技重大专项子课题(2011ZX05024-001-03)资助

摘　　要：针对处理起伏地表(或含地下不规则波阻抗界面)条件下发展起来的地震波场数值模拟算法的模拟结果与解析解(大多数情形下无法得到)无法进行对比,且其有效性和正确性难以验证的情况,本文提出了一种可以相互验证波场数值模拟结果与射线追踪数值模拟结果的正确性和有效性的佐证方法,验证了参考射线追踪法.其中,波场数值模拟中采用曲线网格DRP/opt MacCormack有限差分法,射线追踪模拟则采用分区多步三角网格最短路径算法.通过系统对比上述两种方法得到的波场快照、单炮地震记录,以及合成理论地震图的结果显示,本方法相互作证了两种方法所得结果的正确性和有效性.双层和三层起伏层状模型的对比分析结果表明,这种方法不但可以加深理解地震波在复杂介质中的传播规律,同时射线法的引入为清晰识别和标定地震波场数值模拟中各种不同震相提供了一种便捷的途径.Commonly it is not possible to verify and test the accuracy and validity of the seismic wavefield modeling method,especially when the model surface（or subsurface）is undulated.For this reason,this paper tries an alternative way to mutually verify and test the computational accuracy and the solution correctness of both the ray theory（the multistage triangular shortest-path method）and the wave-equation simulation method（the curvilinear-grid finite difference method of the DRP/opt MacCormack format）in layered isotropic medium.Through the analysis and comparison of wave field snapshot,common source gather profile and synthetic seismogram,it is not only able to verify the accuracy and correctness of each of the methods at least for kinematic features,but also to thoroughly understand the kinematic and dynamic features of the wave propagation in isotropic media.The results show that the curvilinear-grid finite difference method is able to yield the correct results even for complex isotropic media;the multistage triangular shortest-path method is capable of predicting similar kinematic features as the wave-equation simulation method does,which can be used to mutually test each other for methodology accuracy and solution correctness.In addition,with the aid of the ray tracing results,it is easy to identify the multi-phases（or multiples）in the wave field snapshot,common source point gather seismic section and synthetic seismogram predicted by the wave-equation simulation method,which is a key issue for later seismic application.

关 键 词：分区多步三角网格最短路径法 曲线网格有限差分法 地震波传播 数值模拟 起伏层状介质 

分 类 号：P315.31[天文地球—地震学]