半空间地表反射式弹性波多参数反演

Multi Parameter Inversion of Elastic Wave with Surface Reflection Profiling in Half Space

在半空间中及Ｂｏｒｎ近似下，探讨了采用地表发射和地表接收配置下的弹性波方程，得到散射波总场并从中分离出散射波的四类波型转换（Ｐ→Ｐ，Ｐ→Ｓ，Ｓ→Ｓ，Ｓ→Ｐ）．在一个工作频率下，利用这些波型转换得到了多参数（ρ，λ，μ）的具有滤波－反传播形式的反演公式，并对反演公式进行了理论模型验算及分析．

The multi parameter inverse scattering of elastic wave equation is investigated within Born approximation and in half space. The formula of the scattering field of elastic wave is derived using a wideband measuring schemes in which both transmitters and receives scan over the half space surface. Four types of mode conversion of elastic waves (P→P,P→S,S→S,S→P) are separated from the scattering field. These components contain information enough to reconstruct the configurations of the density and Lame parameters of the medium. The inverse formulas, given under single working frequency, have the form of filtered back propagation as in the acoustic diffraction tomogaphy (DT). Computer simulations and analysis are also carried on.