Gradients of Resistivity Profiles Display Fault Systems

Abstract

Gradients of resistivity profiles display fault systems. Fidel CEDILLO fedelecedillo@hotmail.com Keywords: Apparent isoresistivity section (SIRA), vertical electrical sounding (VES), magnetotelluric surveys (MT). Abstract: The analysis and interpretation of the final models of the resistivity profiles (MT, SCHLUMBERGER), demonstrate that changes on the resistivity gradient in geothermal fields or areas with thermal manifestations, show us the presence or absence of geological faults (horsts and gravens) and regional fractures structural represented by structural lineament of volcanic structures. Also these gradients identify conducts of volcanic arcs, corresponding to possible semicircular faults of possibly calderic collapses. And most importantly: identify systems of "hidden faults" covered by successive deposits of lava and pyroclasts. Moreover, resistivities are influenced by the rock type, porosity, permeability, saturation of fresh water or brine, temperature, primary and secondary mineralogy, metallic and non mtallic minerals, altimetry and presence of seawater.