Insights on fault reactivation during the 2019 November 11, <i>M</i>w 4.9 Le Teil earthquake in southeastern France, from a joint 3-D geological model and InSAR time-series analysis

SUMMARY The 2019, Mw 4.9 Le Teil earthquake occurred in southeastern France, causing substantial damage this slow deforming region. Field observations, remote sensing and seismological studies following the event revealed that coseismic slip concentrates at shallow depth along a ∼5 km long rupture associated with surface breaks thrusting mechanism. We further investigate by combining geological field mapping, 3-D geology, InSAR time-series analysis inversion. From structural, stratigraphic data collected around epicentre, we first produce model of region surrounding using GeoModeller software. Our includes geometry layers main faults, including La Rouvière Fault, (LRF) Oligocene normal fault ruptured during earthquake. generate displacement from Sentinel-1 SAR ranging early 2019 January to late 2020 NSBAS processing chain. spatio-temporal patterns for time span show neither clear pre-seismic signal nor significant post-seismic transient deformation. extract pattern time-series, highlighting along-strike variations slip. maximum relative line sight is up ∼16 cm located southwestern part rupture. invert distribution on field. Constraining our model, acceptable dip ranges between 55° 60°. confirms reactivation LRF, reverse very two patches reaching, respectively, 30 24 slip, both 500 m depth. finally discuss how structure may have impacted propagation This study step reassess seismic hazard many faults similar one Cévennes system, densely populated area hosting several sensitive nuclear sites.