Elastic reverse-time migration

Abstract Elastic, prestack, reverse-time, finite-difference migration of two-component seismic surface data requires data extrapolation and application of an imaging condition. Data extrapolation involves synchronous driving of the vertical-component and horizontal-component finite-difference meshes with the time reverse of the recorded vertical and horizontal traces, respectively. Extrapolation uses the coupled elastic wave equation for variable velocity solved with a second-order, explicit finite-difference scheme. The imaging condition at any point in the grid is the one-way traveltime from the source to that point.Elastic migrations of both synthetic test data and real two-component common-source gathers produce simpler images than acoustic migrations because of the coalescing of double reflections (compressional waves and shear waves) into single loci.