黏弹性HTI介质中地震波的传播特征  

The Propagation Characteristics of Seismic Wave in Viscoelastic Horizontal Transverse Isotropy Media

作　　者：何现启 彭凌星 鲁光银[2] 朱自强[2] HE Xian-qi;PENG Ling-xing;LU Guang-yin;ZHU Zi-qiang(Hunan Provincial Communications Planning,Survey&Design Institute co,ltd,Changsha 410008,China;School of Geosciences an Info-physics of Central South University,Changsha 410083,China)

机构地区：[1]湖南省交通规划勘察设计院有限公司,长沙410008 [2]中南大学地球科学与信息物理工程学院,长沙410083

出　　处：《科学技术与工程》2018年第31期7-16,共10页Science Technology and Engineering

基　　金：国家自然科学基金(41174061)资助

摘　　要：为了提高地质勘探的精度,本文主要通过理论推导和数值模型计算研究了黏弹性HTI(horizontal transverse isotropy)介质中地震波的传播特征,其参数包括相速度、慢度、偏振向量等,并基于依据传播方向定义的慢度向量和分量定义的慢度向量,通过求解Christoffel方程推导出黏弹性HTI介质中均匀波的相速度、偏振向量、慢度、群速度的精确计算公式,经过对比分析得出:特殊分量法在给定传播方向N的情况下提供了一种更为简单的求取无约束黏弹性各向异性介质中均匀、非均匀波波动参数的方法。采用特殊分量法,推导了黏弹性HTI介质中非均匀波的二维、三维波动参数表达式,并采用数值模型计算,研究了黏弹性HTI介质中非均匀SH波的相速度随非均匀系数D及弹性参数虚部k值的变化规律,结果表明D影响了地震波的相速度大小,但对其方位特性无影响,可见在黏弹性HTI介质中相速度随方位角变化的规律可指明介质的对称轴方向,k值的大小也对相速度的各向异性产生影响,但沿对称轴方向速度大小不变。In order to improve the accuracy of geological exploration,theoretical derivation and numerical model calculations are used to study the propagation characteristics of seismic waves in viscoelastic horizontal transverse isotropy media.the parameters include phase velocity,slowness,and polarization vector.And based on the slowness vector defined by the propagation direction and which defined by the slowness component,the accurate calculation formula of the phase velocity,polarization vector,slowness and group velocity of uniform wave in viscoelastic HTI media are derived by solving the Christoffel equation,comparative analysis shows that the special component method provides a simpler method for getting seismic wave parameters of homogeneous and inhomogeneous waves in unconstrained viscoelastic anisotropic media.The expressions of the two-dimensional and three-dimensional wave parameters of inhomogeneous waves in viscoelastic HTI media are derived using the special component method.The law of phase velocity for the Inhomogeneous SH wave in viscoelastic HTI media change with inhomogeneous coefficients D and coefficient k is studied.The results show that D affects the value of phase velocity,but has no influence on the azimuth characteristics of the seismic wave.It is concluded that the law of the phase velocity changes with azimuth in the viscoelastic HTI media can indicate the direction of the symmetry axis of the medium and The value of k also affects the anisotropy of phase velocity,but the magnitude of velocity along the axis of symmetry does not change.

关 键 词：黏弹性 HTI介质 相速度 非均匀波 慢度 

分 类 号：P315.31[天文地球—地震学]