Tridimensional Inversion of DC Resistivity Data

Abstract

We have developed a new technique for tridimensional (3D) inversion of DC resistivity data like: dipole-dipole, Schlumberger, pole-dipole, Wenner or a mixture of these. The algorithm has been proved with synthetic data generated with another forward program and the results show that this is an efficient algorithm for recovering 3D structures in subsurface from resistivity data.
The Cerro Prieto region was prospected in 1977-79 with more than 400 long offset Schlumberger soundings. The geothermal area is at the center of a system of echelon faults that produce a slimming and possible rupture of the earth's crust. With the help of the resistivity data, we obtained a tridimensional resistivity image of the geothermal area and of the two principal faults that controls the regional tectonics. We assume that tridimensional inversion gives us a more accurate picture of the region than those bidimensional pictures obtained previously by two-dimensional inversion. We have discovered new features that are not shown in the previous geological models.