Joint Magnetic Resonance and Electrical Resistivity Tomography as hydrogeophysical characterization tool

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As water belongs to the most important resources, hydrogeophysical investigations contribute to the exploration and characterization of aquifers in preparation of water management. Geophysical techniques provide physical parameter of the subsurface non-invasively using measurements at the Earths surface. Two hydrogeophysical techniques, Electrical-Resistivity-Tomography (ERT) and Surface-Nuclear-Magnetic-Resonance (SNMR), have proven to yield important parameter such as water content, hydraulic conductivity and salinity. The impact of combining these techniques using joint inversion has been demonstrated to be superior to individual inversions for 1D layered earth models. However, there is a growing demand for investigation of significantly two-dimensional structures such as karst aquifers, paleo-channels or saltwater intrusion. Main objective of the proposed project is to combine ERT and SNMR in a 2d context with the aim of improved aquifer system characterization as a routine tool for groundwater investigations. Results of the combined inversion developed in this project are two-dimensional images of the parameters resistivity, water content and relaxation time. Their interpretation will allow distinguishing between lithology and fluid properties, which is impossible with electromagnetic methods alone. Based on these primary parameters, porosity, hydraulic conductivity and salinity can be retrieved in order to support groundwater models.