Ritz J.F., Baize S., Ferry M., Larroque C., Audin Laurence, Delouis B., Mathot E. (2020). Surface rupture and shallow fault reactivation during the 2019 Mw 4.9 Le Teil earthquake, France. Communications Earth and Environment, 1, 10 [11 p. en ligne]. ISSN 2662-4435.
Titre du document
Surface rupture and shallow fault reactivation during the 2019 Mw 4.9 Le Teil earthquake, France
Ritz J.F., Baize S., Ferry M., Larroque C., Audin Laurence, Delouis B., Mathot E.
Source
Communications Earth and Environment, 2020,
1, 10 [11 p. en ligne] ISSN 2662-4435
The Rhône River Valley in France, a densely populated area with many industrial facilities including several nuclear power plants, was shaken on November 11th 2019, by the Mw 4.9 Le Teil earthquake. Here, we report field, seismological and interferometric synthetic-aperture radar observations indicating that the earthquake occurred at a very shallow focal depth on a southeast-dipping reverse-fault. We show evidence of surface rupture and up to 15?cm uplift of the hanging wall along a northeast-southwest trending discontinuity with a length of about 5?km. Together, these lines of evidence suggest that the Oligocene La Rouvière fault was reactivated. Based on the absence of geomorphic evidence of cumulative compressional deformation along the fault, we suggest that it had not ruptured for several thousand or even tens of thousands of years. Our observations raise the question of whether displacement from surface rupture represents a hazard in regions with strong tectonic inheritance and very low strain rates.
