Finite-difference modeling of surface waves in poroelastic media and stress mirror conditions  

孔隙介质中面波有限差分模拟及应力镜像条件（英文）

作　　者：张煜[1,2,3] 平萍[4] 张双喜[1,2,3] 

机构地区：[1]武汉大学测绘学院,湖北省武汉市430079 [2]地球空间环境与大地测量教育部重点实验室,湖北省武汉市430079 [3]武汉大学地球空间信息协同创新中心,湖北省武汉市430079 [4]中国科学院测量与地球物理研究所,大地测量与地球动力学国家重点实验室,湖北省武汉市430077

出　　处：《Applied Geophysics》2017年第1期105-114,190,191,共12页应用地球物理（英文版）

基　　金：sponsed by National Natural Science Foundation of China(NSFC,Grant No.41304077);the Natural Basic Research Program of China(the“973 Project,”Grant No.2013CB733303);Postdoctoral Science Foundation of China(Grant No.2014T70740)

摘　　要：During seismic wave propagation on a free surface, a strong material contrast boundary develops in response to interference by P- and S- waves to create a surface-wave phenomenon. To accurately determine the effects of this interface on surface-wave propagation, the boundary conditions must be accurately modeled. In this paper, we present a numerical approach based on the dynamic poroelasticity for a space–time-domain staggered-grid finite-difference simulation in porous media that contain a free-surface boundary. We propose a generalized stess mirror formulation of the free-surface boundary for solids and fluids in porous media for the grid mesh on which lays the free-surface plane. Its analog is that used for elastic media, which is suitable for precise and stable Rayleigh-type surface-wave modeling. The results of our analysis of first kind of Rayleigh （R1） waves obtained by this model demonstrate that the discretization of the mesh in a similar way to that for elastic media can realize stable numerical solutions with acceptable precision. We present numerical examples demonstrating the efficiency and accuracy of our proposed method.地震波沿自由表面传播P波和S波干涉会产生面波现象。因此,地震波数值模拟中需要精确地处理自由表面边界以获取面波传播的数值解。本文提出了一种基于动态孔弹性理论包含自由表面边界处理的时空域交错网格有限差分数值计算方法。针对自由表面,推广弹性介质中的传统应力镜像自由边界处理方法,提出一种新的描述孔隙介质固体和流体自由边界特征适用于面波模拟的应力镜像法。自由表面所在网格节点上的相应镜像的处理就能获得稳定精确的面波数值解。数值模拟得到的第一类Rayleigh波的结果表明该算法在相应的弹性介质中一样的网格剖分下就可获得保证精度的稳定解。数值模拟的例子反映了本文所述方法的有效性。

关 键 词：SURFACE-WAVE POROELASTIC FINITE-DIFFERENCE DISPERSION 

分 类 号：P631.4[天文地球—地质矿产勘探]