A Comparison of Three Array Configurations to Characterize a Fault Zone by the Electrical Resistivity Tomography Method

The electrical resistivity tomography method is able to provide a high resolution section of subsoil where to interpret the faults structure in depth. However, the results with this technique can vary depending on the acquisition array used. In this work we compare three surveys with different array configurations (dipole-dipole, Schlumberger and Wenner) with the aim to optimize the electrical method for the study of fault zones. All of them were applied within a same line of investigation in order to characterize the Ventaniella fault. This is a significant structure in NW Iberia that shows a low but persistent seismicity in some of its segments. It runs for at least 450 km following a NW-SE direction from the continental platform offshore in the Bay of Biscay to the Duero Basin across the Cantabrian Mountains within the Iberian plate. The data obtained has allowed to constrain to what extent the various array configurations are useful in determining internal structure, position and range of depths of the main fault and associated structures.