Migration is a commonly described phenomenon in nature that is often caused by spatial and temporal differences in habitat quality. However, as migration requires energy, the timing of migration may depend not only on differences in habitat quality, but also on temporal variation in migration costs. Such variation can, for instance, arise from changes in wind or current velocity for migrating b...

We present 3D prestack map time migration in closed form for qP-, qSV-, and mode-converted waves in homogeneous transversely isotropic media with a vertical symmetry axis (VTI). As far as prestack time demigration is concerned, we present closed-form expressions for mapping in homogeneous isotropic media, while for homogeneous VTI media we present a system of four nonlinear equations with four ...

Prestack Stolt residual migration can be applied to seismic images that are depth migrated using wavefield extrapolation techniques. This method has significant advantages over other methods that estimate interval velocity functions for depth migration. It is more accurate than methods that are based on focusing the stack of migrated images by a residual NMO operation, so it provides a more acc...

We study the collective dynamics of interacting deformable self-propelled particles whose migration velocity increases with increasing local density. In two-dimensional numerical simulations of this system, the local density dependence on migration velocity leads to traveling bands similar to those previously reported for Vicsek-type models. We show that a pair of straight bands moving in oppos...

The relative efficiency of Common Azimuth wave equation depth migration based on the double square root equation makes it an attractive engine for use in automated velocity updating schemes. One such automated velocity analysis procedure is Differential Semblance Optimization, which constructs velocity updates to reduce, and eventually minmize, a quantitative measure of image gather misfocussin...

Common-reflection-point (CRP) gathers provide important clues in various migration velocity analysis schemes (Al-Yahya, 1987; Etgen, 1990). Conventionally, CRP gathers are obtained by prestack migration of shot records or constant-offset sections. This paper introduces a way to generate a CRP gather for residual velocity analysis using wavefront synthesis imaging. Compared to CRP gathers obtain...