Magnetotelluric Investigations at the Casiri-Kallapuma Geothermal Zone, Tacna, Peru

The studied area is located 91 km from the city of Tacna, in southern Peru, where a grid of 40 MT stations was deployed. Data were processed using standard techniques, with remote reference, static displacement correction, structural impact and dimensionality analysis based on tensor decomposition. MT data were inverted into a fully two-dimensional (2D) resistivity model along two profiles NE-SW (profile 1), NW-SE (profile 2) with an investigation depth of ~ 10 km. The resistivity data were used to develop a subsurface model that has three layers, which were interpreted based on geological and tectonic studies. The resistive surface layer (R1: 50-100 Ohm-m) is located SW of profile 2 and has an average thickness of approximately 1000m from the surface. According to geology, this layer could be associated with volcanic rocks (andesites, trachyandesites) from Casiri hill and the Jucure volcano. The conductive zone (C1: 100 Ohm-m) occurs at depths of more than 5000 m and is still not understood, but the regional geological model suggests an association with the rocks from Cretaceous period.