双相介质瑞雷面波有限差分正演模拟  

Rayleigh surface wave modeling by finite difference method in biphasic media

作　　者：张伟[1] 甘伏平[1] 刘伟[1] 郑智杰[1] 

机构地区：[1]中国地质科学院岩溶地质研究所国土资源部广西壮族自治区岩溶动力学开放实验室,广西桂林541000

出　　处：《物探与化探》2014年第6期1275-1283,共9页Geophysical and Geochemical Exploration

基　　金：国家重点基础研究发展计划项目(2011CB201001);国土资源部公益性行业专项(201211082)

摘　　要：为了研究双相介质瑞雷面波的形成机制及传播规律,促进瑞雷面波资料处理方法的发展。文章根据弹性波动方程,采用交错网格有限差分算法,对二维各向同性弹性介质做解析解与数值解的对比,在此基础上,将PML吸收边界条件,改进的镜像法应用于双相介质波动方程中,并作了稳定性分析,对双相介质水平层状、起伏分界面等典型模型瑞雷面波及体波在内的全波场进行研究。结果表明:基于弹性介质解析解与数值解的对比,在误差接受范围内,研究双相介质是可行的;把稍作改进的镜像法应用于双相介质中,能够有效地处理瑞雷面波自由边界问题;通过详细分析双相介质瑞雷面波及体波在内的全波场的信息,对以双相介质为基础的地震波勘探有一定的指导作用。In order to study the mechanism and propagation of Rayleigh surface wave in biphasic media and promote the development of data-processing method of Rayleigh surface wave, the authors applied finite difference method with staggered grids to simulate the 2D isotropic elastic media based on the elastic wave equation, and made a comparison between the analytical and numerical solutions. On such a basis, the PML absorbing boundary condition and improved image method can be applied to the two-phase medium wave equation to simulate the typical media model including horizontal layer and undulating interface, analyze the full wave information including the Rayleigh surface wave and body wave, and make a stability analysis. The results show that, on the basis of the comparison between the numerical solution and the analytical solution of the elastic media within the acceptable range of the error, the study of biphasic me- dium is feasible. The slight improvement of the image method can be applied to biphasic media to deal with free boundary condition problem of the Rayleigh surface wave effectively. The detailed analysis of the full wave field information of biphasic media including the Rayleigh surface wave and body wave shows that it has played a guiding role in the seismic exploration on the basis of biphasic media.

关 键 词：双相介质 瑞雷面波 有限差分 交错网格 PML吸收边界 镜像法自由边界 稳定性分析 起伏分界面模型 

分 类 号：P631.4[天文地球—地质矿产勘探]