Prestack slant stack migration was implemented with the PSPI algorithm using two reference velocities. This algorithm can handle lateral velocity variations of up to 25 percent. I used both one and two-pass PSPI. The impulse responses of two-pass PSPI are similar to that of one-pass method; however the two-pass method has slightly better accuracy.
After the prestack slant stack migration, the seismic events are lined up at the correct position. It is easier and more accurate to analyze the AVO either in the v domain or in the domain. A good forward and inverse slant stack transform package is necessary to preserve the amplitude.