扩展障碍物的逆时偏移方法:弹性波

Reverse time migration for extended obstacles:Elastic waves

本文针对弹性介质扩展障碍物成像问题,提出了新的单频加权弹性波逆时偏移方法.该成像函数定义为加权弹性波入射场与加权反传播波场互相关的虚部.基于弹性波Helmholtz-Kirchhoff恒等式,给出了弹性波逆时偏移方法的分辨率.该理论结果表明成像函数均为正值,因而对数据噪声具有较好的稳定性.数值算例验证了算法具有强大的成像能力以及理论的合理性.

We propose a new single frequency weighted elastic reverse time migration （RTM） algorithm for imaging extended targets using elastic waves. The imaging functional is defined as the imaginary part of the cross-correlation of the weighted elastic Green function and the weighted back-propagated elastic wavefield. The resolution of our RTM method for non-penetrable extended targets is studied by virtue of Helmholtz-Kirchhoff identity for elastic wave equation. The analysis implies that the imaginary part of our imaging functional is always positive and thus may have better stability properties. Numerical examples are provided to demonstrate the powerful imaging quality and confirm our theoretical results.