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

Marconato, L.; Leloup, P. H.; Lasserre, C.; Jolivet, R.; Caritg, S.; Grandin, R.; Metois, M.; Cavalie, O.; /Audin, Laurence

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dc.creator	Marconato, L.
dc.creator	Leloup, P. H.
dc.creator	Lasserre, C.
dc.creator	Jolivet, R.
dc.creator	Caritg, S.
dc.creator	Grandin, R.
dc.creator	Metois, M.
dc.creator	Cavalie, O.
dc.creator	/Audin, Laurence
dc.date	2022
dc.date.accessioned	2022-04-27T17:37:49Z
dc.date.available	2022-04-27T17:37:49Z
dc.identifier	https://www.documentation.ird.fr/hor/fdi:010084415
dc.identifier	oai:ird.fr:fdi:010084415
dc.identifier	Marconato L., Leloup P. H., Lasserre C., Jolivet R., Caritg S., Grandin R., Metois M., Cavalie O., Audin Laurence. Insights on fault reactivation during the 2019 November 11, M-w 4.9 Le Teil earthquake in southeastern France, from a joint 3-D geological model and InSAR time-series analysis. 2022, 229 (2), p. 758-775
dc.identifier.uri	http://biblioteca-repositorio.clacso.edu.ar/handle/CLACSO/169112
dc.description	The 2019, M-w 4.9 Le Teil earthquake occurred in southeastern France, causing substantial damage in this slow deforming region. Field observations, remote sensing and seismological studies following the event revealed that coseismic slip concentrates at shallow depth along a similar to 5 km long rupture associated with surface breaks and a thrusting mechanism. We further investigate this earthquake by combining geological field mapping, 3-D geology, InSAR time-series analysis and a coseismic slip inversion. From structural, stratigraphic and geological data collected around the epicentre, we first produce a 3-D geological model of the region surrounding the rupture using the GeoModeller software. Our model includes the geometry of the geological layers and the main faults, including the La Rouviere Fault, (LRF) the Oligocene normal fault that ruptured during the earthquake. We generate a time-series of surface displacement from Sentinel-1 SAR data ranging from early 2019 January to late 2020 January using the NSBAS processing chain. The spatio-temporal patterns of surface displacement for this time span show neither a clear pre-seismic signal nor significant post-seismic transient deformation. We extract the coseismic displacement pattern from the InSAR time-series, highlighting along-strike variations of coseismic surface slip. The maximum relative displacement along the line of sight is up to similar to 16 cm and is located in the southwestern part of the rupture. We invert for the slip distribution on the fault from the InSAR coseismic surface displacement field. Constraining our fault geometry from the geological model, acceptable fault dip ranges between 55 degrees and 60 degrees. Our model confirms the reactivation of LRF, with reverse slip at very shallow depth and two main slip patches reaching, respectively, 30 and 24 cm of slip, both around 500 m depth. We finally discuss how the 3-D fault geometry and geological structure may have impacted the slip distribution and propagation during the earthquake. This study is a step to reassess the seismic hazard of the many faults similar to the La Rouviere one along the Cevennes fault system, in a densely populated area hosting several sensitive nuclear sites.
dc.language	EN
dc.subject	Radar interferometry
dc.subject	Seismic cycle
dc.subject	Inverse theory
dc.subject	Time-series analysis
dc.subject	Earthquake source observations
dc.subject	Continental neotectonics
dc.title	Insights on fault reactivation during the 2019 November 11, M-w 4.9 Le Teil earthquake in southeastern France, from a joint 3-D geological model and InSAR time-series analysis
dc.type	text
dc.coverage	FRANCE
dc.coverage	ARDECHE
dc.coverage	LE TEIL