Resistivity Image of the San Andreas Fault System Around the Cerro Prieto Geothermal Area (México)

Abstract

In 1978 and 1979 the Lawrence Berkeley Laboratory (LBL) in collaboration with Comisión Federal de Electricidad (CFE) took 411 long-range schlumberger soundings along 20 lines distributed around the Cerro Prieto Geothermal area. This information was processed and interpreted with the technology of those times. Presently, we rescued that information and interpreted using 3D constrained inversion. The 3D resistivity model shows a conductive thin overburden over a more resistive layer with varying thickness (~600 m) associated with Colorado River alluvial deposits. Below a depth of 1000 m, there are alignments clearly related to the Cerro Prieto and Imperial faults, which are the principal faults of the Mexicali Rift Valley. Both faults show as straight narrow conductive zones offset laterally from each other by the central rift valley, which has a more complex resistivity structure.