Finite-Difference Reverse Time Migration of Multi-ConfigurationMarine Seismic Data

Pre-stack reverse time migration requires that each subsurfacee grid point have a unique imaging time. This time is used to stop the reverse time propagation. Here we compute the required imaging times by using a finite difference algorithm to solve the forward problem. These times, which correspond to the arrival time of the direct wave, are usually found by ray tracing. The procedure we present consists of forward finite difference modelling and detection of the energy of the direct arrival at each subsurface grid point.