The western part of France is characterized by a rich and complex geological history, starting more than 650 Ma. Multiple orogens and successive extension and compression phases occurred, leading to the formation of major faults and shear zones that are still imprinted in the landscape. Currently, the western part of France is considered as a stable continental region, situated away from tectonic plate boundaries. Still, the seismicity records show that the region is active, associated with moderate size earthquakes (Mw 3-4). My work is aiming to characterize the origin of this seismicity, and better understand the role of the inherited faults and shear zones in the current regional deformation.
Above: Map of major inherited faults in western France
Below: Instrumental seismicity (1962-2020) in western France
(see more details in Beucler et al., 2021)