The Joint Task Force for Science Monitoring and Reliable Telecommunications (SMART) Subsea Cables, a United Nations initiative, aims to solve that problem by equipping new commercial undersea telecom cables with simple sensors that measure pressure, acceleration, and temperature. The sensors could be added to the fiber-optic cables’ signal repeaters—the watertight cylinders full of equipment that are used to amplify signals every 50 kilometers or so. With cables providing for the sensors’ power and data transfer needs, scientists could collect information about the seafloor at an unprecedented scale—and pass on data about potential tsunamis far faster than is currently possible.

Adding sensors to undersea cables isn’t a new idea. Bruce Howe at the University of Hawaii, for example, who chairs the task force, operates the deepest science observatory in the world using an abandoned telecom cable located 100 kilometers north of Oahu. But convincing the $5 billion-a-year subsea telecommunications industry to integrate scientific sensors into the expensive hardware it installs has been an uphill battle for a decade, Howe says. 

A big part of the challenge is that a repeater needs to be pressurized against conditions kilometers underwater. Adding external sensors that must be powered by—and communicate with—the repeater complicates the design. But last year Subsea Data Systems, a startup with funding from the US National Science Foundation, built a prototype repeater that showed it could be done. This year the technology is scheduled to have its first true “wet” demonstration when three test repeaters are deployed off the coast of Sicily. Governments—and companies—are starting to get on board. The major telecom cable company Alcatel recently announced it would have SMART cable technology ready by 2025. That same year, Portugal plans to begin work on CAM, a €150 million SMART cable project to connect Lisbon with the islands of Madeira and the Azores. The European Union has designated €100 million for digital connectivity infrastructure, including these types of cable projects. 

These are heartening developments for scientists interested in expanding our ability to study the changing ocean, something that is currently done mostly from space and by research ships.