Making use of elastic wavefield extrapolators to downward continue shots and receivers through layered isotropic or HTI media, we have developed a prestack shot-record elastic migration algorithm. The imaging conditions used are briefly explained, and the migration operators illustrated by impulse responses. Application of the algorithm to modelled isotropic data demonstrates the imaging of a density anomaly in an otherwise laterally invariant medium. The resolution of the P-SV image is superior to that of the P-P, as anticipated. Moreover, the illumination characteristics of the P-SV shot migrations differ in a complementary way to those of the P-P migrations. In future we anticipate extending the algorithm to laterally heterogeneous isotropic and HTI media.
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