Prestack migration by equivalent offset and common scatter point is an alternative method to conventional prestack migration. This method may be applied to converted wave data and extends the concept of equivalent offset to include the appropriate P- and S- wave velocities. In the estimation of the total traveltime in the DSR equation, RMS velocities are required for both the P and S velocities. The P velocity is available from standard P-P processing, and the S velocity is obtained from initial estimates of a converted wave velocity that is a combination of P and S velocities. An assumption of this process is the ratio of the RMS and average velocities are similar for both the P-wave and S-wave velocities. This assumption is evaluated.
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