Seismotectonics in Northeastern France and neighboring regions

The region of northeastern France is affected by low-magnitude background seismicity, with the rare occurrence of moderate earthquakes. which gives this region a non-negligible seismic risk. We provide an overview of the seismicity and seismotectonics of this intraplate domain and of its subregions: the Upper-Rhine Graben (URG), the external range and foreland of Jura, the Vosges. northern France and southern Belgium. Previously published catalogues over historical and instrumental times are used, and the epicentral distribution of earthquakes is compared to known tectonic structures, and the recently computed deformation field. Although no large earthquakes with M-W > 6.0 occurred since the 1356 Basel seismic event (Io IX, MKS). the recent identification of active faults suggests periods of high seismic strain rates in the past. The origin of the seismic activity in each of these sub-regions, characterized by low to very-low strain rates, is attributed to pre-existing faults reactivated under specific natural or anthropogenic conditions.