Wave equation migration is gaining prominence over Kirchhoff methods both as an imaging tool Biondi and Palacharla (1996) and for velocity analysis Clapp (2001). The relatively high cost of downward continuation methods, especially in iterative schemes Biondi and Sava (1999); Prucha et al. (2000), has limited their adoption.
In this paper I discuss three different methods to speed up midpoint-offset domain downward continuation based migration. I compare the migration results with the more standard downward continuation method. I show that a factor of two speed up is achievable with little discernible loss in image quality. In addition I show that for velocity analysis purposes a factor of three to four speed up is achievable.