Near-real time finite fault inversions for large earthquakes in Chile using strong motion data

Abstract

Recent efforts have been made to model the rupture process of large earthquakes in near-realtime in Chile. In the last seven years, Chile has been struck with 3 large earthquakes, with magnitude greater than Mw 8. With the use of the W-phase and other methods, the National Seismological Center (CSN) has reported on the 2014 Mw 8.2 Iquique, 2015 Mw 8.3 Illapel and the 2016 Mw 7.6 Melinka earthquakes with an accurate magnitude just six minutes after the occurrence of all events. In this study, we have developed a methodology that uses strong motion data in an integrated system that can characterize large earthquakes with a finite fault model in near-real time. Based on the preliminary W-phase solutions, we have determined several heuristic rules to determine the geometry and dimensions of the fault planes for the forward modeling portion of the inversion procedure. The results show that with the use of strong motion data and a W-phase magnitude, it is possible to obtain a rapid kinematic finite fault model in just a few minutes after the earthquake origin time.