Porosity of Near-Surface Soil Layers From 3d Elastic Full-Waveform Inversion: Tests on Synthetic Data

Summary The porosity of the shallow soil layers is a crucial information in hydrogeology, soil science, agriculture, and construction engineering. To resolve the spatial distribution of porosity in soil, 3D elastic full waveform inversion (FWI) can be a promising tool. In this research, we have tested 3D FWI on a realistic subsoil model constructed from field-measured data. Different source types, dominant frequency of the seismic source, and the inversion frequency have been examined on the synthetic dataset. Our results suggest that (1) the use of SH and Love waves leads to a higher accuracy compared to P-SV or Rayleigh waves, and (2) the use of a broader frequency range in inversion and/or a source wavelet of higher dominant frequency leads to more accurate and better resolved Vs and bulk-density models. Finally, the porosity values for the different layers have been estimated from the inverted bulk density profile. Our results indicate that 3D FWI has the potential to estimate reasonably accurately the Vs and density profiles, which can in turn offer 3D porosity distribution.