Seismic Response of the Santiago Basin

Funding agency: National Commission for Scientific and Technological Research (CONICYT)

Grant: FONDECYT Regular 1190995 (2019-2023)

Principal Investigator: Cesar Pasten

Co-Principal Investigators: Sergio Ruiz and Rodrigo Astroza

Two mega-thrust earthquakes have struck the Santiago Basin in the last thirty years: the 1985 Mw 8.0 Valparaiso and the 2010 Mw 8.8 Maule earthquakes, both causing significant damage and MSK intensities that ranged between VI and VIII. The economic and political relevance of the Santiago city for the Chilean development requires an accurate prediction of its seismic response behavior upon the most important seismic hazards, among which are the interface mega-thrust earthquakes along the subduction margin in Central Chile, the intraplate intermediate-depth earthquakes in the Nazca plate, and the shallow crustal earthquakes associated to the San Ramon fault, a west-vergent thrust fault located along the eastern border of the Santiago city at the foot of the main Andes Cordillera. Since the Santiago metropolitan area is extending to less-competent soil deposits and zones dominated by complex interaction of sediments and topographic features, it is crucial to understand the parameters that control its seismic behavior. Therefore, this project proposes the development of an unprecedented 3D structural model of the Santiago Basin at multiple scales and the use of numerical methods to predict its seismic behavior, accounting for the interaction of different materials, the nonlinear material behavior, the geometry of the Basin, and the seismic sources that can generate significant ground motion.