Reverse time migration for extended obstacles: Elastic waves

Abstract

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.