Sladen A. auteur aut IRD Rivet D. auteur aut IRD Ampuero Jean-Paul auteur aut IRD De Barros L. auteur aut IRD Hello Yann auteur aut IRD Calbris G. auteur aut IRD Lamare P. auteur aut IRD text journalArticle eng text/pdf reformatted digital access Two thirds of the surface of our planet are covered by water and are still poorly instrumented, which has prevented the earth science community from addressing numerous key scientific questions. The potential to leverage the existing fiber optic seafloor telecom cables that crisscross the oceans, by using them as dense arrays of seismo-acoustic sensors, remains to be evaluated. Here, we report Distributed Acoustic Sensing measurements on a 41.5 km-long telecom cable that is deployed offshore Toulon, France. Our observations demonstrate the capability to monitor with unprecedented details the ocean-solid earth interactions from the coast to the abyssal plain, in addition to regional seismicity (e.g., a magnitude 1.9 micro-earthquake located 100 km away) with signal characteristics comparable to those of a coastal seismic station. specialized 066 032 10 5777 [8 ] 2019 2041-1723 https://www.documentation.ird.fr/hor/fdi:010077465 10.1038/s41467-019-13793-z 2041-1723 [F B010077465] https://www.documentation.ird.fr/hor/fdi:010077465 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers20-01/010077465.pdf IRD - Base Horizon / Pleins textes 2020-02-05 2025-02-24 fdi:010077465 fre