Evidence of seismogenic activity of Perales Fault in the Ixtlahuaca Basin, Mexico

The study area is located in central Mexico, in the Trans-Mexican Volcanic Belt (TMVB) one of the areas with highest geological activity. The structural framework that controls the kinematics of the studied area is linked to the Acambay graben, characterized by structures mainly oriented E-W, where the November 19, 1912, Ms 6.9 earthquake took place. The lacustrine and fluvial sequences of Ixtlahuaca basin are currently affected by faults and uplift of Perales fault footwall, which has migrated into the basin during the Late Quaternary. The Ixtlahuaca-basin has been considered as aseismic zone, however, soft sediment deformations and paleoliquefaction features are clearly genetically related with synsedimentary faulting of the lake basin floor. The identified structures and the application of the ESI 2007 scale (Michetti et al, 2007) suggests a seismically induced origin; the deformational structures are similar and the intensity in the two areas is from VII to IX.