Numerical Simulations of Global Seismic Wave Propagation

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EAR-0003716Tromp, JeroenThe investigator has developed and implemented a spectral-element method (SEM) for the simulation of three-dimensional (3D) seismic wave propagation. The method has been benchmarked against discrete-wavenumber/reflectivity synthetics for layercake models, and it has been demonstrated that the effects of free surface topography, attenuation, anisotropy, and fluid-solid boundaries can be accurately accommodated. The method will be used to assess seismic risk in the L.A. area based upon a 3D basin model. The main objective of this proposal is to extend the SEM to include global wave propagation. The code has been successfully benchmarked against normal-mode synthetics for a 3D Earth model with a size of 1/6th of the mantle by volume and the isotropic, elastic structure of the Preliminary Reference Earth Model PREM. A conforming mesh that enables the modeling of wave propagation in the entire Earth has been constructed. To accurately model 3D global wave propagation the effects of anisotropy, attenuation, self-gravitation, and a stably stratified fluid core need to be incorporated.