f A practical implementation of the multi-processing 3D Kirchhoff prestack migration scheme on the cray Y-MP systems

The implementation of a full three-dimensional prestack seismic migration on the multi-processor CRAY Y- MP system is presented. The computational algorithm is designed to maximize the processing availability. It utilizes the advanced technologies of multi-processor architecture, I/O subsystem (IOS) and Solid-State Storage (SSD) on the Y-MP system. The implementation can be applied equally well for both time and depth migrations as long as the traveltime trom surface shot or receiver positions to all depth points is precalculated. The region of parallelism is extended to nearly 100 percent of the computational procedure. Because of the short processing period, the implementation is attractive for iterative migration of a real 3-D survey with updated velocity functions .