THE SERVITA FAULT, EASTERN CORDILLERA, COLOMBIA, AND ITS ROLE IN THE SEISMIC HAZARD OF BOGOTÁ D.C

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). This is one of the main faults of the Eastern Frontal Fault System (EFFS) that define the llanos foothills of Colombia and from its morphotectonic expressions, which is of great dimensions compared to the one displayed by other faults recognized as having potential seismoactivity. It´s estimated that it can produce earthquakes of at least M > 7.0. Among the faults that belong to the EFFS, this fault is the closest one to the metropolitan area of Bogotá D.C. . Four magnitude 5.0 or higher earthquakes were confirmed by both historical and instrumental seismicity information has been registered in its influence area to this day. Of these earthquakes, two have transcended in this region due to the economic slump and loss of lives that it caused: 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 and/or other small faults associated to this can produce a big earthquake very close to metropolitan area of Bogota D.C. where most of its soils were derived of a Late Pleistocene big lake. For this last reason if the Servita fault or one of its associated produces an earthquake with a magnitude (M) > 6.5 more of the 60 % of urban area will would destroy resulting in high losses in lives and economic terms.