HOME > NATION > Article

Text Size

small

medium

large


Japanese Agency Observes Tsunami with Submarine Optical Cable

Japanese Agency Observes Tsunami with Submarine Optical Cable

   Tokyo, June 6 (Jiji Press)--The Japan Agency for Marine-Earth Science and Technology, or JAMSTEC, said Thursday that it observed a tsunami that occurred off Torishima, an island in the Izu chain in the Pacific, in October last year using the long-distance fiber-optic cable it placed for research purposes on the seabed off Cape Muroto in the western prefecture of Kochi.
   A tsunami changes water pressure in the sea and the submarine topography, slightly altering the shape of the fiber-optic cable. This creates a gap in the round-trip time of a laser light transmitted through the cable from a base station on the ground, making it possible to observe tsunami and earthquakes.
   The cable extends some 100 kilometers southward from an area near Cape Muroto and can identify a section of several to several tens of meters whose shape changed due to an earthquake or tsunami.
   It successfully observed a tsunami between a point some 60 kilometers off the cape and an area near the cape as it continued a survey on slow earthquakes that had occurred along the Nankai Trough since January 2022.
   Currently, the fiber-optic cable cannot estimate the height of a tsunami. However, Takashi Tonegawa, a senior researcher at JAMSTEC, said, "If we understand the physical characteristics of the optical fiber and subseafloor structure in advance, the height of a tsunami can be calculated."

To read a full story, please click here to find out how to subscribe.

NATION

HEADLINES

POLITICS
US Nuclear Submarine Makes Port Call in Cuba, Where Russian Fleet Anchored
ECONOMY
Toyota to Continue Production Halt for 3 Models in July over Testing Scandal
SPORTS
Volleyball: Japan Women Qualify for 6th Straight Olympics at Paris 2024
OTHER
5 Environmental Activists Arrested over Jingu Gaien Redevelopment in Tokyo

AFP-JIJI PRESS NEWS JOURNAL


Photos