An undersea internet cable network that runs about 2,175 miles (3,500 kilometers) along Chile’s coast is being turned into an earthquake sensor. Universidad T\u00e9cnica Federico Santa Mar\u00eda (USM) announced the deal with the telecom company Gtd on December 29, 2025. The partners will connect a sensing instrument to one fiber of Gtd’s Prat cable and measure along 62 miles (100 kilometers) of it.<\/p>\n\n\n\n
According to the university, the aim is to test an early warning system for earthquakes and, eventually, tsunamis. A French and Chilean team already used the same cable to record a magnitude 5.7 quake in November 2021. The newest study asks how fast the fiber can say how big a quake is.<\/p>\n\n\n\n
Tom\u00e1s B\u00e4rthold, Gtd’s infrastructure strategy manager, signed for the company. M\u00f3nica Pacheco, USM’s director general of research, innovation and entrepreneurship, signed for the university. The deal runs for one year and renews automatically, according to the USM announcement<\/a>.<\/p>\n\n\n\n Marcelo Soto, a professor in USM’s Department of Electronics and a researcher at the AC3E engineering center, leads the team. The first system will go in at the Prat cable’s landing node in Conc\u00f3n. Cartagena, Constituci\u00f3n, Biob\u00edo and La Serena could follow.<\/p>\n\n\n\n In Spanish, Soto said the data will feed artificial intelligence tools already built at USM and AC3E “and thus improve the precision in earthquake detection and optimize response times.” He added that the fiber could also track waves, currents and tides. Other projects already test fiber sensing on offshore mooring lines<\/a>.<\/p>\n\n\n\n For Gtd, the monitoring could also help anticipate possible cuts in the cable. Chile’s Undersecretariat of Telecommunications has publicly backed the project.<\/p>\n\n\n\n The technique is called distributed acoustic sensing, or DAS. An instrument at one end of the fiber fires laser pulses. It then reads the tiny share of light that bounces back from natural impurities in the glass.<\/p>\n\n\n\n A passing seismic wave stretches or squeezes the glass by a minute amount, and the reflected light comes back a hair early or late. In the 2021 Chilean test, those delays were read every 4 meters (13 feet). That spacing shows how the cables that carry most of the internet<\/a> could double as a ready-made listening network.<\/p>\n\n\n\n Diane Rivet, a seismologist at the C\u00f4te d’Azur Observatory and the G\u00e9oazur laboratory in France, described the method in 2021. In a University of Chile release, she said one fiber can act as several thousand seismic sensors. The reach goes up to 93 miles (150 kilometers).<\/p>\n\n\n\n The Prat cable first proved useful in the Submarine Earthquake Observation Project, known by its Spanish initials as POST. Rivet led it with G\u00e9oazur colleagues and Chile’s National Seismological Center (CSN), based at the University of Chile.<\/p>\n\n\n\n On October 27, 2021, the team plugged a DAS unit into one of the cable’s 36 fibers at Conc\u00f3n. It used 93 miles of that fiber as a line of seafloor sensors. On November 3, the cable recorded a magnitude 5.7 earthquake<\/a> centered about 62 miles from Conc\u00f3n.<\/p>\n\n\n\n According to the University of Chile, it was the first experiment of this kind on a commercial cable. Rivet had earlier detected quakes with DAS in Europe, on cables built only for research.<\/p>\n\n\n\nLaser pulses inside the glass<\/h2>\n\n\n\n
The magnitude 5.7 test quake<\/h2>\n\n\n\n