A probabilistic seismic hazard map for the metropolitan France

Abstract

This paper presents the development of a probabilistic seismic hazard analysis (PSHA) model to compute seismic hazard maps for the French territory taking into account 15 years of research and development in the area. Since 2002, when the first probabilistic hazard map was computed for France, many new data became available leading to new studies and experience gained. This 2017 PSHA version for France incorporates significant improvements over previous version. In particular, the recent SIGMA project 2010–2016 produced a number of outputs which are used in the present analysis: a homogenized earthquake catalogue in moment magnitude (Mw), a Bayesian methodology to compute distributions of maximum magnitudes, ground motion prediction equations specifically developed for the French territory, new seismotectonic analysis conducted based on geological, structural, geophysical, neotectonic and seismological data. Preliminary comparison of median PGA values at 475 years return period with results obtained independently for neighboring countries (Germany, Switzerland, and Italy) reveals a fair agreement. Comparison with the 2013 European Seismic Hazard Model (ESHM13, SHARE project) and the model for France developed in 2002 indicates that 2017 PSHA version leads to lower hazard.