‘Smart’ fiber-optic cables on the sea floor will detect earthquakes, tsunamis, and global warming

Everybody in Portugal knows the date: 1 November 1755. It was All Saints’ Day, with candles lit in homes to honor ancestors. Then the earthquake struck, cracking the streets of Lisbon open and sparking a firestorm. A tsunami engulfed the port, and tens of thousands died. Even now people are aware of the threat— from a nearby seafloor junction where the grinding tectonic plates of North America, Eurasia, and Africa meet—says José Barros, who retired recently from a senior role at ANACOM, Portugal’s telecom regulator. “We are always having those thoughts—and fears.” Soon Lisbonites may be able to count on tsunami warnings of half an hour or more. In the next few months, Portugal is expected to sign a deal to begin work on a new 3700-kilometer-long fiber-optic cable stretching west across the floor of the Atlantic Ocean to Madeira and the Azores, almost to the seafloor junction. One of the world’s first “smart” cables, capable not only of carrying internet data, but also monitoring the ocean above and the earth below, the €154 million cable will be able to detect tsunami waves practically where they are spawned. For more than a decade, geophysicists have pushed telecom operators to consider smart cables. For a 10% to 20% increase in cost, they say, companies could squeeze three simple sensors—for seafloor motion, water pressure, and temperature—into the cables’ repeaters, widened sections that amplify the optical signal every 70 kilometer...
Source: ScienceNOW - Category: Science Source Type: news