Summary The hydrocarbon prospects in mountainous areas require solving a most challenging problem in seismic imaging --irregular topography associated with a rugged terrain, complexity of the nearsurface that includes high-velocity layers and outcrops with significant lateral velocity variations, complexity of the overburden, and the complexity of the target imbricate structures themselves. We ...

A new approach to seismic migration formalizes the classical diffraction (or common-tangent) stack by relating it to linearized seismic inversion and the generalized Radon transform. This approach recasts migration as the problem of reconstructing the earth’s acoustic scattering potential from its integrals over isochron surfaces. The theory rests on a solution of the wave equation with the geo...

Summary We perform a series of numerical modelling and migration experiment with different homogeneous TTI anisotropic media, characterized by tilt axis, polar velocity and anisotropy parameters. In the case of structurally conformable media, where the tilt of the medium coincides with the dip of the structure, great simplifications arise in the decoupling of the anisotropy parameters. In parti...

Common-image gathers are an important output of prestack depth migration. They provide information needed for velocity model building and amplitude and phase information for subsurface attribute interpretation. Conventionally, common-image gathers are computed using Kirchhoff migration on commonoffset/azimuth data volumes. When geologic structures are complex and strong contrasts exist in the v...

[1] The character of the mantle flow field in subduction zones remains poorly understood, despite its importance for our understanding of subduction dynamics. In particular, little attention has been paid to mantle flow beneath subducting slabs. In order to identify processes that make first-order contributions to the global pattern of subslab mantle flow, we have compiled shear wave splitting ...

Wavefield extrapolation by spatially variable phase shift is currently a migration tool of importance. In this paper, we present a new prestack seismic migration algorithm using the Gabor transform with application to the Marmousi acoustic dataset. The imaging results show a very promising depth imaging algorithm, which is competitive with the best depth imaging algorithms. The Gabor depth imag...

Formation of lamellipodia and the retraction of ruffles are essential activities during motility and migration of eukaryotic cells. We have developed a computer-assisted stroboscopic method for the continuous observation of cell dynamics (stroboscopic analysis of cell dynamics, SACED) that allows one to analyze changes in lamellipodia protrusion and ruffle retraction with high resolution in spa...

We show how liquid migrates in sheared unsaturated granular media using a grain scale model for capillary bridges. Liquid is redistributed to neighboring contacts after rupture of individual capillary bridges leading to redistribution of liquid on large scales. The liquid profile evolution coincides with a recently developed continuum description for liquid migration in shear bands. The velocit...

Reverse-time migration can accurately image complex geologic structures in anisotropic media. Extended images at selected locations in the earth, i.e. at commonimage-point gathers (CIPs), carry enough information to characterize the angle-dependent illumination and to provide measurements for migration velocity analysis. Furthermore, inaccurate anisotropy leaves a distinctive signature in CIPs,...

(40) Where zi is the charge number of species i in the solution. Mass transfer arises either from the differences in electrical or chemical potential or from the movement of a volume element of the solution. It can occur due to: • Migration which is the movement of a charged body due to an electric field, i.e., an electrical potential gradient. The flux density of a species i in the solution du...