Phase shift plus interpolation with uncorrelated anisotropic parameters

Abstract

Seismic imaging methods such as phase shift plus interpolation achieve computational efficiency by reducing the associated P-wave velocity model to a small set of reference values. Anisotropy complicates this reduction because multiple parameters characterize an anisotropic model, and they do not necessarily correlate in space. Rather than attempting to find reference parameters for potentially uncorrelated anisotropic models, I find a set of reference traveltimes based on the spatial variation of horizontal slowness at the evanescent boundary. Strong changes in that horizontal slowness mark zones of strong changes in the combined effect of the anisotropic parameters simultaneously, and I use these zones to define the set of reference traveltimes. Based on traveltime comparisons and impulse responses, I find that reference traveltimes rather than reference parameters return greater accuracy with a more reasonable computational cost.