Explicit approximate equations describing the physical meaning of the migrated sections are derived. The equations are applicable to 3-D elastic migrations in 3-D isotropic or anisotropic, heterogeneous velocity models. The imaged combination of elastic parameters (reflectivity) depends on the selection of the polarizations of the incident and back-propagated wavefields and on the directions of propagation. The migrated section is then approximately equal to the convolution of the unknown exact reflectivity function with the local resolution function. The local resolution function depends on the aperture and on the imaging function. The imaging function is determined by the source time function and by the form of the imaging functional.
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Klimes, L.: Resolution of prestack depth migration. Stud. geophys. geod., 56 (2012), 457-482.