f A Practical implementation of a 3D pre-stack depth migration algorithm

Full 3D Pre-stack Depth Migration (3dpsdm) is a computational problem that is pushing the seismic exploration industry to the leading edge of computational capabilities. The algorithm of choice for depth migration is Kirchhoff migration [Ref.1]: given an input trace and the travel times from an output image point to the source and receiver locations of that trace, the input datum recorded at the sum of those travel times (TT) is summed into the image. Kirchhoff depth migration consists of three steps: a travel time calculation (given an initial velocity model), the imaging step proper, and a quality control and diagnostics step which may lead to a (partial) update of the velocity model and a corresponding re-migration since the quality of the imaging step strongly depends upon the accuracy of the velocity model and the level of sophistication of the travel time calculation algorithm [Ref .2]. In this Paper we will concern ourselves only with the imaging step proper.