Single-scattering parabolic equation solutions for elastic media propagation, including Rayleigh waves

The parabolic equation method with a single-scattering correction allows for accurate modeling of range-dependent environments in elastic layered media. For problems with large contrasts, accuracy and efficiency are gained by subdividing vertical interfaces into a series of two or more single-scattering problems. This approach generates several computational parameters, such as the number of interface slices, an iteration convergence parameter tau, and the number of iterations n for convergence. Using a narrow-angle approximation, the choices of n = 1 and tau = 2 give accurate solutions. Analogous results from the narrow-angle approximation extend to environments with larger variations when slices are used as needed at vertical interfaces. The approach is applied to a generic ocean waveguide that includes the generation of a Rayleigh interface wave. Results are presented in both frequency and time domains. (C) 2012 Acoustical Society of America. [DOI: 10.1121/1.3675554]