The new Italian seismic hazard model

Abstract

In 2015, the Seismic Hazard Centre (CPS) of the Istituto Nazionale di Geofisica e Vulcanologia (INGV) was commissioned to engage and coordinate the national community with the aim of elaborating a new reference seismic hazard model, which is expected to be released in mid 2018. CPS outlined a roadmap to describe the main features of this complex endeavour, including the different scientific tasks, milestones and timelines. The scientific tasks focus their work on i) improving the quality and the accuracy of the input data (e.g. historical seismic catalogue, seismotectonic zonation, etc.); ii) building new earthquake rate models based on these new input data, iii) selecting the most proper ground motion prediction equations, iv) testing the overall seismic hazard model as well as each component; v) combining the results of the statistical testing phase and the outcome of an expert's elicitation session to assign a weight to each component of the final seismic hazard model. The new seismic hazard model is based on an innovative coherent probabilistic framework, which allows a proper description of the aleatory variability and epistemic uncertainty, and the validation of the seismic hazard model. Here, we describe the progresses made up to now, the comparison between the new and the official national model, and finally we discuss the scientific aspects that have the most significant impact on the new picture of PSHA in Italy.