Introduction

Modeling of elastic wave propagation in layered anisotropic media is usually done by a reflectivity method (e.g., Mandal and Toksoz, 1990, or Fryer & Frazer, 1984,1990). In the reflectivity method, the amplitudes of the waves propagating in all the layers are solved for in one large system of equations. In the phase shift method that I propose, a step-by-step approach is used. Although this method is probably less efficient than the reflectivity method it does allow me to modify the amplitudes of the different wavetypes at each step. I can zero all the P-wave amplitudes at each step of the algorithm to produce an S-wave only section or zero all the S-wave amplitudes to create a P-wave section. Since my method generates one order of multiples for each pass through the heart of the algorithm, I can produce a primary only section or a specific order of multiples.

While all of these things may be done in a reflectivity algorithm, it is simpler and, I hope, more intuitive with a phase shift algorithm.