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. © Diane Rivet. |