Van den Ende M. auteur aut IRD Ampuero Jean-Paul auteur aut IRD Courboulex F. auteur aut IRD Delouis B. auteur aut IRD Godano M. auteur aut IRD Larroque C. auteur aut IRD Sladen A. auteur aut IRD text journalArticle eng text/pdf reformatted digital access Recent developments in Distributed Acoustic Sensing (DAS) have greatly expanded our capabilities for dense geophysical instrumentation by tapping into existing (but unused) fibre-optic telecommunica-tion networks. Leveraging these so-called 'dark fibres' permits an extremely rapid deployment of thousandsof vibration sensors over distances of several tens of kilometres, which is ideal for rapid postseismic responseefforts. Here we report on the use of dark-fibre DAS for monitoring of the aftershock sequence of the 2019-11-11 Mw4.9 Le Teil, France earthquake. Through comparison with the local seismometer network, we assess the capabilities of the DAS array to detect and locate small-magnitude seismic events. Likely owing to cabledeployment and DAS sensing characteristics, we find that the DAS noise floor is up to 3 orders of magnitudehigher than that of nearby seismometers, which greatly inhibits the detection and analysis of the low-energyevents. However, locating a selected aftershock with DAS yields an accuracy and precision that is comparableto that of the seismic network, even though the DAS array has a relatively unfavourable geometry. Based onthese observations we provide a number of recommendations for routinely incorporating DAS into postseis-mic response protocols, and for optimal use of DAS alongside conventional seismic instrumentation. specialized FRANCE 066GPHGEN 066SISMO 4 1 en ligne [15 ] 2025 2816-9387 https://www.documentation.ird.fr/hor/fdi:010093685 10.26443/seismica.v4i1.1204 2816-9387 [F B010093685] https://www.documentation.ird.fr/hor/fdi:010093685 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/2025-05/010093685.pdf IRD - Base Horizon / Pleins textes 2025-04-07 2025-11-04 fdi:010093685 fre