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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.

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Stanford Exploration Project

12/18/1997