Peligrosidad sísmica de la costa norte de Ecuador y el terremoto de Pedernales de 2016

Abstract

In the northern region of Ecuador, there is a major coupling between the Nazca and South American tectonic plates, which causes that approximately every 20 years an interplate earthquake with smooth angle of dip, and magnitude moment greater than 7. On April 16, 2016, an earthquake of magnitude 7.8, with epicenter in Pedernales, Ecuador, left many damages in the structures, one of the main causes was the seismic action, which was greater than those recommended by seismic regulations. Close to the epicenter area, the spectral ordinates were three times larger than those obtained with the latest seismic regulations of 2015. Therefore, a revision of the design spectra is necessary, especially in the Esmeraldas and Portoviejo provinces.
In this article we present the seismic risk in uniform spectra, in rock, for Manta city, for three returning periods, considering three models of strong movements and using a logical tree for the evaluation of seismic hazard. On the other hand, the source areas considered and the seismic parameters of each of them are indicated. Finally, the spectrum for a returning period of 475 years is compared with the recommended by the Ecuadorian Construction Standard of 2015, where greater
spectral orders can be seen for the zone of constant acceleration in relation to NEC-15 regulation.