Fig. 1

Study area and location of magnetotelluric sites. From west to east, the main morpho-structures that dominate the study zone correspond to the coastal mountain range that dates from the Paleozoic and is made up of the western series, the central valley made up mainly of marine Cenozoic volcanic rocks and glacial sediments and the Andes mountain range where the Nor-Patagonic batholith is developed, made up mainly of alkaline plutonic rocks from the Middle Jurassic to the Miocene. Dotted line represents the trace of the Liquiñe Ofqui fault zone LOFZ, L.LL Lake Llanquihue, LTS Lake Todos los Santos and VO, VC, VP, VT represents the Osorno, Calbuco, Puntiagudo and Tronador volcanoes respectively