Joint Inversion of Seismic Refraction and Resisitivity Data Using Layered Models

We present a layer-based joint inversion of refraction seismic and geoelectric data and show its utility by applying it to a field example from western Sweden. The joint inversion couples the two data sets by assuming the electrical and acoustic parameters to have a common layer structure, but otherwise leaving them to vary freely (laterally within those common layers). The lateral parameter variations are constrained as previously proposed for pure resistivity inversion (Auken & Christiansen 2004). We assume our assumptions are justified for sediment bedrock situations in ground water exploration. We compare the joint inversion results with those obtained from single inversions, and conclude that it is mostly the seismic data constraining the structure. The particular situation under consideration exhibits a pathological hidden-layer situation, where mere seismic exploration may be inaccurate. In cases like these, the joint inversion allows an improved determination of the structure compared to seismic inversion alone. The resistivity distribution, and also to a lesser degree the velocity distribution, benefit significantly from being constrained by the improved structure.