INRiM, with National Physical Laboratory (UK, coordinator) and Google, published on Science the study “Optical interferometry–based array of seafloor environmental sensors using a transoceanic submarine cable” that demonstrates that laser interferometry, a technique initially developed for atomic physics and optical clocks, can turn ocean floor cables into a grid of geophysical sensors.
By launching narrow-linewidth light into a 5,860 km-long intercontinental optical fiber deployed in the Atlantic Ocean between the UK and Canada, the team showed the detection of earthquakes and ocean signals, such as waves and currents.
The laser-based detection of such events with the same fibers that are already in place for internet data exchange brings us information from remote areas of the Planet which are currently unsurveilled due to the technical difficulty in placing traditional sensors, and effectively transforms the underwater telecom infrastructure into a giant array of geophysical sensors.