BS in Physics
John J. Jasbinsek
The resolving power of two-dimensional Direct Current (DC) Electrical Resistivity Tomography (ERT) is investigated in the context of shallow faults. Subsurface electrical resistivity data was collected perpendicular to a secondary fault scarp of the Los Osos Fault Zone with a Syscal KID Switch 24 resistivity meter and processed with Prosys II and Res2DInv software to produce two-dimensional cross sections of resistivity values via a smoothness-constrained least-squares optimization method. Comparison of ERT inversion results to a trench wall map of the same fault scarp suggest the location and dip direction of faults is resolvable, while detailed fault structure, such as dip angles, are not. These results show that non-invasive reconnaissance subsurface exploration with resistivity surveying is a valuable complementary tool to other shallow geophysical exploration methods such as refraction seismology.