Introduction

The migration of the slant stack of common midpoint gathers is a method that makes no assumptions that deteriorate with wide offset angles, steep dips, or vertical velocity variations. Events of different dips that intersect are equally well-imaged.

Ottolini 1982 proposed the equations for and some applications of common midpoint slant stack migration. The migration can be implemented with either the F-K or the phase-shift algorithm. But his algorithm only allows for velocity variations in depth. Hence, I extended Ottolini's algorithm by using the phase shift plus interpolation (PSPI) methodGazdag and Sguazzero (1984), taking lateral velocity variations in slant stack migration into account Lin (1993).

Keho et. al 1992 use such migrated $\tau-p$seismic data to do amplitude-versus-offset (AVO) processing. Their paper shows that prestack migration collapses diffractions, focuses bright spots, and moves them to their proper location.

I migrated one synthetic and one field dataset by prestack slant stack migration with PSPI, and compared the migrated section with the model that generated the synthetic dataset. I then implemented the AVO analysis program to analyze the migrated CMP gathers.