Electrical Resistivity Tomography Modeling of Vertical Lithological Contact using Different Electrode Configurations

In the present study, three different electrical resistivity electrode configurations (Dipole-Dipole, Wenner-Schlumberger, and Wenner configurations) were applied to a geological outcrop that demonstrates a lateral lithological variation at sub-vertical contact. The main target was to examine the intrinsic characteristics of resistivity configurations and consequently to determine the optimum one that has to be selected in such a geological environment. The results of resistivity models provided comparable tomograms at different number of accepted quadripoles and varied RMS%. Based on statistical fitting criteria between four simulated tomograms and three measured inverted tomograms, the inversed twelve data sets produced for three resistivity configurations are capable of defining vertical and horizontal structures with varied sensitivity and fitting values. In particular and according also with known geological outcrop’s dimension and lithological layers, Dipole-Dipole resistivity tomogram can be considered as the most sensitive configuration to localized and extended conductive structure at the highest correlation coefficient. On the other hand, Wenner-Schlumberger and Wenner tomograms based configurations can resolve localized horizontal conductive layer beneath resistive layer. In particular, the high resistivity contrast for geoelectrical layers allowed producing similar resistivity tomograms down to 20 m depth.