Abstract

VILLAROSA, Gustavo et al. Origin of the tsunami of may 1960 in the LakeNahuel Huapi, Patagonia: application of the high-resolutionbathymetric and seismic techniques. Rev. Asoc. Geol. Argent. [online]. 2009, vol.65, n.3, pp.593-597. ISSN 0004-4822.

Thetsunami recorded in the Lake Nahuel Huapi, Patagonia Argentina, on May 22, 1960is the first example of a tsunami in a continental lake in Argentina.High-resolution bathymetry (SBMF), 2 high-resolution seismic profiles togetherwith three short sedimentary cores allowed linking this tsunami to the 1960earthquake of Valdivia, the strongest (Mw 9.5) ever instrumentally recordedearthquake. The impact of the seismic waves produced huge mass-failure below70-80 m water depth. The failure was probably induced by the presence of anon-cohesive surface (tephra layer?) that acted as a sliding surface, and the mobilizedmaterial evolved into a mega turbidite in the deep basin. A large volume ofwater was displaced by the mobilization of these sediments producing a tsunamithat hit the coasts of Bariloche and destroyed the harbor of thecity.

Keywords : Tsunami; Earthquake-induced landslides; Nahuel Huapi Lake; 1960 earthquake; High-resolution bathymetry; Seismic profiles.

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