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Shallow-Seismic Wavefield Scattering and Implications for Viscoelastic FWI
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 25th European Meeting of Environmental and Engineering Geophysics, Sep 2019, Volume 2019, p.1 - 5
Abstract
The aim of this study is to investigate the seismic response from shallow structures using a 2D finite-difference method. Full-waveform inversion (FWI) suffers from so-called cross-talk between viscoelastic parameters, i.e. certain combinations of viscoelastic parameters have the same scattering signature. We evaluate the scattering response from individual perturbations in the viscoelastic material parameters. By subtracting a perturbed from a background medium and solving the viscoelastic wave equation we obtain the scattering wavefield. Additionally, we evaluate the instantaneous energy density of P- and S-waves to better understand the influence of scattering. This allows us to provide some fundamental insights into the composition of seismic recordings and ideas of how to mitigate cross-talk in shallow-seismic applications of FWI. Specifically, we find that the P-wave velocity structure is constrained similarly by Rayleigh, P- and S-waves. The S-wave velocity is the most reliable parameter to invert for from FWI of surface waves due to their large amplitudes. The scattering pattern of density differs fundamentally from those of velocities and attenuation. Finally, cross-talk between attenuation and velocity for both P- and S-waves is caused by the similarity of their corresponding scattering responses.