Integrating seismic and electromagnetic reflections to derive subsoil information

Abstract

For many applications in environmental and geo-technical engineering applications, the distribution of soil parameters is required. The present approach is to make CPT’s at a regular grid with distances between the verticals of up to 200 m. To increase the data volume, cone resistance and seismic cone tests are added to the regular failure test of a CPT. This leads to more data in the 1D-volume without the possibility to properly interpolate between the verticals. We propose to use a combined analysis of seismic and GPR data to derive soil parameters directly from the geophysical parameters creating an almost continuous data volume of desired variables. As a first step, we introduce models to derive seismic and electromagnetic bulk properties for a porous soil using known parameters of the constituents and the porosity and water saturation of the soil. The bulk parameters are obtained from different mixture rules, depending on the variable. From the combined analysis of seismic data and GPR data, we are able to reconstruct the porosity and water saturation from the reflection amplitudes. Only when the seismic data is used with the GPR data in an integrated cost functional, unique results for the desired parameters are obtained.