The Nokia Bell Labs team has turned a 4,400-kilometer undersea cable linking California and Hawaii into a network of 44,000 virtual seismic stations. Using distributed acoustic sensing (DAS), the fiber optic detects tiny seabed vibrations, including earthquakes and tsunami signals, without affecting internet traffic.
It was previously thought that signal amplifiers in cables would make this impossible, but the researchers found a way to use built-in feedback loops to amplify the desired signal. The system has already successfully recorded an 8.8-magnitude earthquake off Kamchatka and related underwater processes.
Its main advantage is that no new equipment needs to be laid. Existing cables can be turned into scientific instruments simply by connecting a special laser. This makes global ocean monitoring accessible and inexpensive.
Beyond seismology, DAS can also be used to study whales, ocean currents, and the structure of Earth’s mantle. Despite some limits on access to private cables, the technology is already ready for broader deployment and opens new horizons for science.
