Approach for combining faults and area sources in seismic hazard assessment: Application in southeastern Spain

Abstract

Abstract. This paper presents a methodological approach for seismic hazard assessment that considers a hybrid source model composed by faults as independent entities and zones (containing the residual seismicity). The seismic potential of both types of sources is derived from different data: for the zones, the recurrence model is estimated from the seismic 10 catalog. For fault sources, it is inferred from kinematic parameters derived from paleoseismicty and GNSS measurements.Distributing the seismic potential associated to each source is a key question when considering hybrid models of zone and faults, which some authors solve by assigning to the fault only the earthquakes that exceed a fixed magnitude value Mc. In the present approach, instead of restricting the magnitudes of each type of source, the distribution of seismic potential is carried out only for magnitudes below the maximum magnitude value completely recorded in the catalog (Mmaxc). This is 15 derived from a completeness analysis and can be lower than the Mmax generated by the faults, taking into account that their the recurrence period can be higher than the observation period of the catalog.The proposed approach is applied in southern Spain, a region of low-to-moderate seismic where faults move slowly. The results obtained are contrasted with the results of a seismic hazard model using the traditional zone model exclusively.Results show a concentration of expected accelerations around fault traces using the hybrid approach, which is not 20 appreciated in the classic approach using zones exclusively.