Abstract:

Angle domain illumination can be used to analyze underground complex geological body. In this paper, we proposed a method of angle-domain illumination analysis at rugged surface. The main process is using local slant stack technique to decompose seismic wavefield, and judging weighting function for rugged surface to determine the aptitude of the Green function within local time window to distinguishing whether it is above or underneath the surface. Semblance function to calculate local plane wavefield for anti-aliasing is introduced. According to the relationship between local slope of the plane wavefield and angle of incidence, we obtained the local angle domain seismic wavefield. Using the relationship between time-angle domain illumination and Paz Val equation, we calculated the illumination intensity in angle domain. During a test on an ore body under rugged surface, we acquired the angle domain illumination intensity and the relationship between the intensity of the underground point and the position of shot and the incident angles of the wavefield in the given observing systems. This method could be applied to optimizing observing systems on ragged surface and pre-stack AVA analysis.

Key words: rugged surface, angle domain, illumination, seismic waves