Rapid computation of multioffset vertical seismic profile synthetic seismograms for layered media

Abstract

By rearranging the formulas for the responses of buried sources and receivers in the Kennett reflectivity algorithm, we have obtained a new algorithm that is very efficient for computing multioffset VSP synthetic seismograms. The rearrangement of the response formulas is quite general inasmuch as it applies to both isotropic and anisotropic Kennett codes. Our new algorithm and the original single‐receiver algorithm can both be made to run much faster on vector computers by taking the layer loop out of the p-loop, but leaving it inside the frequency loop. The resulting vector codes can still compute the response of media with frequency‐ dependent velocities.