Abstract: An improved method is disclosed for obtaining shear wave data from common depth point gathered compressional wave traces using variations in the amplitude of the gathered compressional waves with source receiver offset. The shear wave data is determined from measured compressional amplitude offset values and incident angles of shear wave data. The incident angles are determined from the offsets and smoothed interval velocity functions.

Abstract: Method for determining the presence of hydrocarbons in subsurface geological formations by comparative assessment of compressional wave reflection information and shear wave reflection information estimated from acquired compressional wave information from common depth point gathered compressional wave traces using variations in the amplitude of the gathered compressional waves with source-receiver offset.

Abstract: An improved method is disclosed for obtaining shear wave data from common depth point gathered compressional wave traces using variations in the amplitude of the gathered compressional waves with source receiver offset. The gathered compressional waves are corrected for normal moveout and the normal moveout corrected waves are further corrected for residual normal moveout by correcting stacking velocities of the normal moveout corrected traces.

Abstract: A method is disclosed for obtaining shear wave data from common depth point gathered compressional wave traces using variations in the amplitude of the gathered compressional waves with source-receiver offset. The shear wave data can be used to generate pseudo-shear wave seismic sections.

Abstract: In seismic exploration, the ratio of the velocities of compressional and shear wave data is automatically determined by cross-correlating a compressional wave trace against a window of the shear wave trace to produce a set of correlation coefficients as a function of P wave time. The shear wave window is shifted by an increment of time. The steps of cross-correlating and shifting the window are repeated to form a grid of correlation coefficients. Points on the grid represent the correlation coefficients between a point on one trace and a point on the other trace. The path of maximum correlation coefficients, or maximum likelihood functions, through the grid identifies the V.sub.p /V.sub.s profile. This path is selected by a process which includes selecting the best path between two points and then increasing the number of points in the sequence until the best path through the grid is determined.