The Servita Fault, Colombian Eastern Cordillera: Origin, Geotectonics, and Seismicity

Abstract:

The Servita fault is a thrust located in the center of Colombia and whose main scarp is at 5 km west of Villavicencio (500.000 inhabitants). According to geophysics data as gravity, magnetic, and seismic, this fault was confirmed how a large cortical structure in the Colombian Eastern Cordillera. The Servita fault possibly was originated like a suture that derived of a continental collision in Late Mesoproterozoic times when Rodinia was conform totally. The Servita Fault as normal fault in Mesozoic times contributed to the Colombian Cretaceous basin development. In Late Cretaceous because to collision of the Caribbean plate with the northwestern corner of South America a strong compressive stress was occur and kinematics changes were presented in the normal faults restrained to the basin like among others the Servita Fault, where these were converted in inverse faults. From early Pliocene until Present times the Servita Fault controlled the growth of the Cordillera and the Llanos foothills in this sector of Central Colombia. Result of this is the seismicity activity registered for this region from historical times (less of 500 years for Colombian case).

Two earthquakes have transcended in this region in last three centuries: the first one occurred on October 18th, 1743 with a current probabilistic magnitude greater than 6.5 and the second one struck on May 24th, 2008 with a M = 5.9.

In this work we show how this fault has develop from its origin, and how this can would produce a M > 6.5 earthquake very close to metropolitan area of Bogota D.C., and Villavicencio. This earthquake would destroy both urban areas resulting in high losses in lives and economic terms. The seismicity activity of the Servita Fault and its associated structures is registered by the National Seismological Network of Colombia and the Sabana de Bogotá Seismological Network.