Wave equation migration of turning waves

Abstract

Traditional one‐way wave equation migration recursively downward continues the wavefield and usually ignores the turning waves that propagate beyond 90 degree. It fails to produce good image of the geologic structure that contains strong turning waves, such as the overhanging salt boundary. Full‐wave based reverse‐time migration certainly handles this case, but it's computationally expensive. Here we propose a one‐return wave equation migration to extrapolate both down‐going and up‐going waves. Followed by a properly designed imaging condition, the partial image contributed form turning waves is correctly reconstructed. A numerical example shows that this method can significantly enhance the overhanging salt boundary.