A detailed analysis of body waves simulated in homogenized media
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Abstract
Non-periodic homogenization has proved to be an accurate asymptotic method for
computing long-wavelength equivalent media for the seismic wave equation, turning
small-scale heterogeneities and geometric complexity into smooth elastic properties.
Using homogenized media allows i) decreasing the computation cost of wave propagation
simulation and ii) studying the apparent, small-scale-induced anisotropy. After illustrating
these two aspects briefly, we propose to analyze in great detail the accuracy of body waves
simulated in homogenized 3D models of the subsurface. First, the behaviour of head-,
reflected and refracted waves with respect to source-receiver o\set, maximum frequency
and velocity contrast across a planar interface, is investigated. Then, we consider the SEGEAGE overthrust model to exemplify how the accuracy of simulated body waves anticorrelates with the distance to seismic source and the amount of apparent anisotropy. In
high apparent anisotropy regions, we show that the first-order correction provided by the
homogenization theory significantly improves the computed wavefield. The overall results
of this analysis better frame the use of homogenized media in seismic wave simulation.