Empirical radiation patterns as a method to assess crosstalk under scenarios of heterogeneous reference media

Mariana Lume, Ivan Sanchez, Kristopher A. Innanen

Analysis of radiation patterns is the most common method to evaluate crosstalk between parameters in Full Waveform Inversion problems. Typically, these are constructed from analytic expressions subject to not so realistic assumptions, such as the use of homogeneous reference media. This study focuses on introducing a workflow to extract the empirical radiation patterns from simulated scattered wavefields and on making use of it to assess the Vp, Vs and density scattering patterns generated from wavefields produced under different heterogeneous backgrounds. To achieve this, radius dependent masks to isolate displacements of interest and sweeps of angles were used. The proposed workflow is beneficial since it allows to extract highly accurate empirical patterns and demonstrates that, under heterogeneous scenarios, the shape of the radiation patterns has certain changes from what is theoretically expected, and that slightly different crosstalk regions from those indicated by the analytic expressions might occur, as well as sensitivity variations.