Seismic waves generated by a 1.9 magnitude earthquake located north of Fréjus (Var), recorded along the 41 km-long fibre optic cable deployed on the seafloor off Toulon. In the recording on the right, each line corresponds to a measuring point located along the cable, from the coast (at top) to the open ocean (at bottom). (The 41 km of cable are the equivalent of over 6000 sensors). The difference in the arrival time of the waves at the various measuring points is used to pinpoint the location of the earthquake.
Scientists have for the first time shown that it is possible to detect the propagation of seismic waves on the seafloor using submarine telecommunications cables. According to their observations, this existing infrastructure could be used to detect earthquakes, as well as swell and underwater noise. The results are published on December 18, 2019, by researchers from the CNRS, OCA, IRD and Université Côte d’Azur working together in the Géoazur laboratory, in collaboration with the company Fébus Optics and the Centre de Physique des Particules de Marseille (CNRS/Aix-Marseille Université) 1.
