Abstract

SAGRIPANTI, Guillermo Luis  and  VILLALBA, Diego. Prehistoric and recent movements in the Argentine intraplate, at the latitude 33º S, Las Lagunas fault, Sampacho, Córdoba. Rev. Asoc. Geol. Argent. [online]. 2011, vol.68, n.4, pp.491-501. ISSN 0004-4822.

Las Lagunas fault is located in the argentine intraplate at latitude 33ºS, in the southern region of the Cordoba province. This structure with proved Quaternary activity has records of strong paleoearthquakes, historical earthquakes, and associated frequent seismicity. Paleoseismic and geodesic methods have permitted to quantify the prehistoric and recent movements of the fault. Paleoseismic studies done in trenches across the fault, have permitted the recognition of coseismic deformation corresponding to four paleoearthquakes occurred in the upper Holocene. This information has allowed estimating a vertical displacement of the fault of 0.20 mm/yr and a horizontal of 0.16 mm/yr. in Chañaritos section of Las Lagunas fault, a geodesic net was placed to detect and to measure slow vertical and horizontal movements. The net is composed of six stations, located in the hangingwall and footwall blocks of the fault. Precision measurements were made with an electronic total station. Four measurements were made between years 2003 and 2010, and this information has permitted to interpret a change in the sense strike of movement and a 37 millimeters coseismic displacement of, which is assigned to an unique natural event like the earthquake of M 8.8 in Concepción, Chile 2010.

Keywords : Fault; Intraplate; Geodetic techniques; Paleoearthquakes; Trench.

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