AMENAZA SÍSMICA EN LA REGIÓN DE LOS ANDES VENEZOLANOS.

Due to the existence of the Boconó strike-slip fault system, along with parallel inverse faults, the Venezuelan Andes presents a high seismic hazard, historically manifested by a series of destructive earthquakes. For the new Venezuelan Seismic Building Code, an evaluation of the seismic hazard has been developed, based on a new seismogenic model. The resulting peak accelerations are compared in this work for 8 cities with those of the current code, as well as two precedent works. The map of the new evaluation allows greater detail to one of the previous maps, which evidences the concentration of seismic hazard around the recognized faults, mainly the Boconó fault. Concerning the current code, there is a decrease in the seismic hazard to the north (Carora and Barquisimeto), little variation towards the center-north (Trujillo, Valera, and Escuque), an increase in Mérida state (including the flank towards El Vigía) and a relatively small variation in Táchira state, with some increase in La Fría. For both codes and the 8 cities, elastic spectra at rock are presented, as well as design spectra for an intermediate site class and certain regular buildings. In the elastic spectra, an increase in acceleration of 20% is observed at short periods in Merida state for the new code relative to the current one; lower increases are observed in Táchira state and decreases in Trujillo, Barquisimeto, and Carora. In the considered design spectra an increase of up to 50% is observed for short periods, while in both cases the differences are smaller for intermediate and long periods. These values agree with the diversity of destructive historical earthquakes according to the states, except for Barquisimeto. The low values in Carora coincide with the absence of severe seismic intensities to date. [ABSTRACT FROM AUTHOR]