Magnetotelluric Characterization of Faults and Fault Systems in the Cusco Valley, Southern Peru
DOI:
https://doi.org/10.47347/incasciences.v1i1.27Keywords:
Magnetotelluric, Active Faults, Conductive zone, Resistive zone, Seismic HazardAbstract
In this study we present the result of a magnetotelluric (MT) investigation carried out in April 2018 across the main faults and fault
systems identified along the Cusco Valley, southern Peru. The profile trends southwest-northeast (SW-NE) and consist of 14 MT
soundings with a spacing of 500-700 m. At each location data were recorded for 10 to 24 hours, in order to measure the subsurface resistivity to a depth of ~6 km. The data were converted into a model of subsurface electrical resistivity using 2-D inversion algorithm. This resistivity model was interpreted on the basis of geology and structural studies. Considering that fault zones have been showed relatively conductive responses in other studies, we interpret that the conductive zones identified in the electrical resistivity model
suggest a significant correlation with traces of the active faults of the Cusco Valley. We also show, for the first time, the geometry in depth (~6 km) of an extensive system of interlocking faults consisting of several normal and active faults. It also invites us to consider the Cusco fault as an active tectonic structure, which could increase the seismic hazard in the Cusco Valley.
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