Finite Element Reverse Time Imaging for Earthquake Sources and Scatterers

Abstract

In this study, we applied the reversibility of elastic wave to a discussion of the reverse time propagation of wave equation. Based on the backward propagation concept, we evaluated the feasibility of reconstructing the image of elastic wave sources and scatterers. The finite element method was used to calculate elastic wave propagation in the medium. The same computational code was also used to reconstruct the reverse time image. It was found that after our careful processing of the absorption boundary for artificial reflection, we could use the time-trace records at the surface to invert the locations of seismic sources or underground scatterer accurately. Our results show that point source, finite fault and multi-sources are well reconstructed. Although direct waves are much stronger than scattering wavefields, the imaging of the underground anomaly is still well reconstructed from the reverse time process. The image reconstruction technique based on the finite element method is flexible and easily to use for many applications.

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