HIGHLY ACCURATE P-SV COMPLETE SYNTHETIC SEISMOGRAMS USING MODIFIED DSM OPERATORS

In previous papers [Cummins et al., 1994ab] (hereafter referred to as DSMI and DSMII respectively), we presented accurate methods for comput ing complete synthetic seismograms for SH and P-SV respectively in a s pherical earth model. The SH calculations used computationally efficie nt modified matrix operators, but the P-SV synthetics were computation ally intensive. Geller and Takeuchi [1995] (hereafter referred to as G T95) presented a general theory for deriving modified operators and ga ve the explicit form of the modified operators for the P-SV case in cy lindrical or cartesian coordinates. In this paper rye extend GT95's re sults to derive modified operators for the P-SV case in spherical coor dinates, The use of the modified operators reduces the CPU time by a f actor of about 5 without a loss of accuracy. 10 CPU min on a SPARC-20 workstation with one CPU are required to compute a profile of syntheti c seismograms from DC to 20 sec period.