Integración de fallas a escala de sistema como fuentes para un cálculo probabilista de la peligrosidad sísmica de las Béticas Orientales

Abstract

The inclusion of faults as seismogenic sources in probabilistic seismic hazard assessments (PSHA) has become a common practice as more and higher quality paleoseismic data on faults has become available. Moreover, the occurrence of earth- quakes with complex fault-ruptures has evidenced the need to understand faults as interacting systems rather than indepen- dent sources. In this study, we present a PSHA for the SE of Spain in which we have considered the main faults of the Eastern Betics Shear Zone (EBSZ) as seismogenic sources. In contrast with previous studies in Spain, and in order to account for fault interaction, we considered different scenarios of multi-fault ruptures at a system-level for the source modelling. These models, previously published in Gómez-Novell et al. (2020), are weighted in a logic tree for the calculations. The results show a clear control of the EBSZ faults in the seismic hazard for all return periods, especially for 2475 and 4975 years. The peak ground acceleration (PGA) values are increased up to ~1g in some areas with respect to the models that do not consider faults as sources. These maximum values concentrate around Alhama de Murcia and Carboneras faults, the ones with higher activity rates. Despite the results, it should be considered that the hazard models strongly depend on quantity and quality of the geological data available on the faults. Such uncertainties are a key discussion point at the EBSZ.