Abstract: A method for geophysical exploration by analyzing shear-wave polarization directions relative to a fixed coordinate frame is disclosed, for either vertical seismic profile data or surface seismic reflection data. Energy in a selected time window of two off-diagonal components is determined, and the source and receiver coordinate frame is then rotated, and energy is again determined. A second rotation of the source and receiver coordinate frame is followed by a third energy determination. A simple trigonometric function equation is generated to fit the determined energy values, and a minimum energy value is determined. The coordinate frame is then rotated by the angle that gives the minimum energy value, so that all of the signal is put on the diagonal components.

Abstract: A method for analyzing seismic shear wave data, using a layer stripping technique, to determine fault plane stress build-up is disclosed. Polarization directions of shear wave data, from either a vertical seismic profile or from surface reflection data, are analyzed, and time lags between fast and slow split shear wave are determined. Natural polarization directions of and time lags between the split shear waves in an upper layer are determined above the shallowest depth where data cues suggest polarization changes take place. Source and receiver axes of the data below the depth of polarization changes are rotated by an azimuth angle, to bring the axes into proper alignment. A static time shift is then applied to eliminate the time lag in the upper layer above the depth where polarization changes were indicated. Shear wave polarization azimuth angles, and time lags between the shear waves are determined for the depth of investigation, and are compared to the strike of a nearby fault.

Abstract: A method for analyzing seismic shear wave data, using a layer stripping technique, to predict subsurface stress regimes is disclosed. Polarization directions of shear wave data, from either a vertical seismic profile or from surface reflection data, are analyzed, and time lags between fast and slow split shear wave are determined. Natural polarization directions of and time lags between the split shear waves in an upper layer are determined above the shallowest depth where data cues suggest polarization changes take place. Source and receiver axes of the data below the depth of polarization changes are rotated by an azimuth angle, to bring the axes into proper aligment. A static time shift is then applied to eliminate the time lag in the upper layer above the depth where polarization changes were indicated.