Levantamiento magnetotélurico en el area de Culiacán, Sinaloa

Abstract

We report a remote reference magnetotelluric survey performed in La Presita area, in the neighborhood of Culiacán, Sinaloa (México). Fifteen soundings were carried out along three lines, two transversal and one parallel to the geological strike of the region. Due to excessive industrial and agricultura! activity and the high electrical conductivities found in the coastal plain, signals are generally low in amplitude and contaminated with noise. On account of the use of the remote reference station, and a special processing of the data, consisting of an adequate selection of segments with high coherencies for each frequency window, it has been possible to obtain information with good statistical properties. In order to perform the interpretation of the data, we first identify the polarization mode of each apparent resistivity and phase curves by using impedance and tipper polar diagrams, and induction arrows.Finally, a two-dimensional modelling is included in the interptetation, taking into account all the geological and geophysical knowledge of the area. We have modified, by numerical experiments, our final model within realistic bounds: there are no evidences of the existence of geothermal resources in this area.