S U M M A R Y One way of developing a wave-equation approach to seismic imaging is based on the concept of downward continuation of observed surface reflection data. Seismic imaging is typically based on the single scattering approximation, and assumes the knowledge of a smooth background model in which the mentioned downward continuation is carried out using the double-squareroot (DSR) equatio...

Data mapping is a procedure for transforming seismic or acoustic data collected with one set of source/receiver locations and wavespeed model, to data equivalent to that collected in a diierent source/receiver connguration and wavespeed model. A major application of this general process is downward continuation of the waveeeld, or wave-equation datuming. Unlike many previous implementations of ...

the problem of downward continuation of the gravity field from the earth’s surface to the reference ellipsoid arises from the fact that the solution to the boundary value problem for geoid determination without applying stokes formula is sought in terms of the disturbing potential on the ellipsoid but the disturbing gravity observations are only available on the earth’s surface. downward contin...

$EVWUDFW With airborne gravimetry routinely reaching accuracies of 1-2 mGal at 5-10 km resolution, it is a challenge to perform a reliable downward continuation of the gravity anomalies at altitude. Airborne gravimetry is especially suited for geoid determination in mountainous and polar regions, due to the random, alias-free sampling of the terrain, relative to typical surface surveys. In the ...

Unlike many previous implementations of Kirchhoo-type waveeeld extrapolation (Berryhill, 1979; Bevc, 1995), we propose a procedure that is not only kinematically correct , but dynamically correct in heterogeneous media, in a model-consistent sense. Our approach is to specialize the general,\true-amplitude" data mapping platform of Bleistein & Jaramillo (1997) to the process of downward continua...

In this paper I discuss three different methods to speed up midpoint-offset domain downward continuation based migration. I compare the migration results with the more standard downward continuation method. I show that a factor of two speed up is achievable with little discernible loss in image quality. In addition I show that for velocity analysis purposes a factor of three to four speed up is...