Fallamiento y sismicidad del área entre Cartago y San José, Valle Central de Costa Rica

Faulting and seismicity of an area located between Cartago and San Jose, in central Costa Rica,have been analyzed. Most of the area belongs to the Central Valley and only its southwestern part to theTalamanca Ridge. Faults were determined by neotectonic criteria, using mostly air photos and fieldreconnaissance. In order to look for the best correlation between faults and earthquakes, we selected the bestevents located between 1992 and 1996 by the Red Sismologica Nacional (ICE-UCR). The selected hypocentersshow three main seismic clusters; one is located in the San Miguel-Higuito-Patarra (SMHP) area and correlateswith the Agua Caliente fault. The second one is located near Escazu and can be related with the Belo Horizontefault. The third one is located near Tobosi. High quality focal mechanisms from these seismic clusters, indicatedifferent types of seismic slip.