Parameter crosstalk and leakage between spatially separated unknowns in viscoelastic full-waveform inversion

Abstract

Elastic and attenuative effects play a major role in the determination of wave amplitudes and phases observed at seismic sensors. Viscoelastic full-waveform inversion (FWI) has the potential to recover much of the information content of measured seismic data by simultaneously accounting for these effects. However, the frequency variations and phase information present in viscoelastic FWI introduce new challenges to the inversion, especially through their impact on interparameter crosstalk. Crosstalk is typically characterized through analysis of the radiation patterns of point scatterers; however, the point scatterer model is not well suited to viscoelastic FWI because (1) attenuation introduces a significant potential for crosstalk between variables distant from one another in space and (2) interpreting the effect of frequency and phase dependence on the radiation patterns of point scatterers is not straightforward. We have introduced and examined a numerical approach for assessing the viscoelastic crosstalk modes expected for a given parameterization, optimization strategy, and acquisition geometry based on differencing various synthetic inversion results. With this approach, we have characterized the viscoelastic crosstalk for a typical parameterization for several possible acquisition geometries. Of particular note is the strong tendency for [Formula: see text] variables to leak into elastic variables from which they are spatially separated.