Numerical Tools for Multiscale Wave Propagation in Geophysics
Authors: Jose Camata (Federal University of Rio de Janeiro), Lucio de Abreu Correa (French National Center for Scientific Research), Luciano de Carvalho Paludo (French National Center for Scientific Research), Regis Cottereau (French National Center for Scientific Research), Alvaro Coutinho (Federal University of Rio de Janeiro)
Abstract: Current methods of elastic tomography in geophysical media are mainly based on the arrival times of the first waves, which correspond to a particular homogenization regime. The late coda, that corresponds to a diffusion-like regime is mostly disregarded. We want to complement the classical tomography methods with statistical information gathered from the coda. Such an objective requires the construction of numerical tools that can efficiently adapt to the required scale of study, in particular (i) a scalable mesh device that automatically considers topographical details up to a parameterizable level (ii) a spectral element solver for elastic wave propagation, and (iii) a scalable random field generator for elastic parameters. We address item (i) with an octree-based meshing algorithm accounting for the depth-dependent velocity structure of the Earth. Item (iii) is dealt with by a superposition algorithm adapted when the propagation length is large compared to the correlation length.
Two-page extended abstract: pdf