Phase correction in separating <i>P</i> - and <i>S</i> -waves in elastic data

Abstract

Abstract Two-dimensional elastic data containing reflected P-waves and converted S-waves generated by a P-source may be separated using dilatation and rotation calculations (Sun, 1999). The algorithm is a combination of elastic full wavefield extrapolation (Sun and McMechan, 1986; Chang and McMechan, 1987, 1994) and wave-type separation using dilatation (divergence) and rotation (curl) calculations (Dellinger and Etgen, 1990). It includes (1) downward extrapolating the (multicomponent) elastic data in an elastic velocity model using the elastic wave equation, (2) calculating the dilatation to represent pure P-waves and calculating the rotation to represent pure S-waves at some depth, and (3) upward extrapolating the dilatation in a P-velocity model and upward extrapolating the rotation in an S-velocity model, using the acoustic wave equation for each.