Nonlinear Least-Squares Estimation of Shear Wave Speeds in Viscoelastic Media

Rapid simulations of three-dimensional (3D) shear wave propagation in viscoelastic media with a Kelvin-Voigt model are enabled by Green's functions accelerated with graphics processing unit (GPU) parallelization using high performance computing (HPC) resources. From 3D waveforms, shear wave speed estimates are obtained through cross-correlations, where previous efforts have demonstrated that errors in the estimated shear wave speed increase with rising viscosity. To reduce the error in the shear wave speed estimate, a nonlinear least-squares approach accounting for propagation, attenuation, and waveform spreading is proposed for viscoelastic materials. The nonlinear least-squares approach yields an estimate of shear elasticity and shear viscosity.

Automated summary

This study conducts rapid simulations of three-dimensional shear wave propagation in viscoelastic media using a Kelvin-Voigt model, accelerated by Green's functions with GPU parallelization and HPC resources. Shear wave speed estimates are obtained through cross-correlations from 3D waveforms, and a nonlinear least-squares approach is proposed to reduce the error in estimation by considering propagation, attenuation, and waveform spreading.