IGEBA   23946
INSTITUTO DE GEOCIENCIAS BASICAS, APLICADAS Y AMBIENTALES DE BUENOS AIRES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Structural Characterization of the Strike-Slip El Tigre Fault by 2D Electric Resistivity Tomographies
Autor/es:
FAZZITO, S.Y., BELLO CAMILLETTI, G., RAPALINI, A., CORTÉS, J. M. Y TERRIZZANO,C.M.
Lugar:
Buenos Aires
Reunión:
Otro; XIV GIAMBIAGI WINTER SCHOOL; 2012
Institución organizadora:
Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires
Resumen:
The El Tigre Fault is a major morphotectonic feature in the western Precordillera of San Juan (Argentina). It is a 120-km long N-S trending transcurrent fault with neotectonic activity evidenced by several tens of meters of dextral displacement of Pleistocene alluvial fans and creeks. Nine 2-D electric resistivity tomographic (ERT) surveys were carried out along the Central Segment of this fault. Six (up to 710 m long) were orthogonal across the main fault trace, two were long (over 1.4 km) surveys parallel to the main fault, while the last was deployed across subtle geomorphic features suggesting folds of Quaternary deposits 2 km East from the main fault trace. The 2D ERT models permit to characterize several important structural features of the El Tigre fault. They show that minor but significant curvatures of the main fault trace are expressed in the subsurface according to the local stress regime associated to the dominant strike-slip regime of the fault. As such, the geophysical models show that at releasing bends of the trace, the main fault adopts a geometry compatible with extensional features. On the other hand, at restraining bends, geophysical images of the margins of large pressure ridges suggests that they are not produced as positive flower-type structures, but as folded strata against the main fault. Parallel ERT demonstrate that the El Tigre Fault is segmented by several transversal high angle faults, possibly reactivated basement faults, which have conditioned its kinematic evolution.