Seismicity of the Austral Andes, Southernmost Patagonia

Abstract

Since December 2018, the first seismic network deployed around the Austral Andes and its Southern Patagonian Ice Field is recording passive seismicity at the western margin of Southern Patagonia, Southernmost South America. Here, active tectonics is dominated by the interplay between the Antarctic plate's subduction at the trench and the sinistral transform movement of the Scotia plate to the south. This research shows the first catalogue of crustal seismicity located in this region, for almost a year of recording (from December 2018 to mid-November 2019). We finally localized 2685 seismic events, using an automatic event detection algorithm called REST, a new 1-D Minimum Velocity Model constrained with VELEST, and a probabilistic location approach using NonLinLoc. We identified several seismicity clusters, from west to east: in the forearc, under the Reclus volcano, and in different sections of the fold and thrust belt. Additionally, seismic events aligned with the transform boundary to the south suggest a broader area of active deformation.