oa Stochastic Analysis of Cross-hole Gpr Data for Subsurface Characterization

We analyze the relationship between cross-hole GPR travel times and the spatial distribution of dielectric properties that conditions such data. The most common approach is to translate directly travel times into electromagnetic velocities and these in turn into dielectric constants and soil volumetric moisture content. This approach is known to lead to over-smoothed moisture content profiles that are not necessarily compatible with the true soil moisture content that should be reproduced by water flow models. We used an approach based on full waveform propagation and Monte Carlo simulations to assess, in both synthetic and real case studies, how reliable this direct wave approach is, and to develop an alternative stochastic inversion procedures that proves to provide robust estimates of soil moisture content profiles, also in presence of sharp boundaries.