Deformación Tectónica Cuaternaria Y Migración Del Frente De Empuje Del Cerro La Cal : Implicancias Paleosísmicas

Resumen

The overall pattern of surface deformation in the<br>vecinity of the migrated Cerro La Cal Thrust Front is<br>explained as the effects of fault-plane bending. The<br>Frontal Fault had been active until early Pleistocene<br>time. This reverse fault thrusts the Cerro La Cal over a<br>pile of basin-fill sediments, and a sedimentary wedge<br>was formed on its down-thrown side. In middle<br>Pleistocene time (?), a low-angle thrust was formed in<br>the sedimentary wedge presumably as a bedding slip.<br>As a result, the Frontal Fault became inactive and the<br>location of the surface faulting advanced 0.6 km basinward.<br>Coseismic deformation associated with the 1861<br>earthquake occurred entirely along the migrated La Cal<br>thrust fault. This seismogenic fault advanced east-ward<br>at a migration rate of 0.75 mm/yr.