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 strategy explored here is to leverage the network of fiber optic seafloor telecom cables already in place and that criss-cross the oceans. This is made possible by the metrological approach called Distributed Acoustic Sensing (DAS) which analyze the properties of the light back-propagated to infer strain variations of the fiber. I will present results of measurements performed on the 41.5 km-long MEUST-NUMerEnv telecom cable deployed offshore Toulon, France. Our observations demonstrate the capability of the approach to turn the cable into a dense network of seismo-acoustic sensors; here we recorded at 2kHz over more than 6500 sensors. With these sensors we can monitor with unprecedented details the ocean-solid earth interactions from the coast to the abyssal plain, the propagation of waves generated by regional micro-earthquakes or simply track passing boats. The ability of DAS to provide a dense sampling of the seismo-acoustic wavefield over large distances is unique and paves the way to many more applications and new discoveries.
Anthony Sladen: https://asladen.github.io