Fiber-optic cables that make up global undersea telecommunications networks may help researchers assess offshore earthquakes and hidden geologic formations at sea depths, according to a study. The study, published in the journal Science, described an experiment that became a 20-kilometer section of undersea fiber-optic cable equivalent to 10,000 seismic stations monitored along the seabed.
Researchers at the University of California (UC) Berkeley in the US recorded a magnitude 3.5 earthquake, and earthquake scattering from underwater fault zones during their four-day experiment.
They used a technique in which a device with components was used to manufacture the light and sent short pulses of laser down the cable to detect the light, and discovered that due to the stretch in the cable How it was backcatched due to the stretch.
The researchers then measured the scattering on every two meters of the cable, and transformed the 20-km section into 10,000 individual motion sensors.
He said that this technique can be used to map previously unknown fault systems, and observe many dynamic tides and storm-driven processes in the water column above.
He said a technique called distributed acoustic sensing was first tested with a fiber-optic cable on the ground, but can now be used to obtain data on lakes under the sea, where some seismic stations exist , They said.
Researchers said the new system is sensitive to changes from nanometers to hundreds of pixometres for every meter of cable length – a scale change of one billion to one part.
The study’s author, Nat Lindsay, told UC Headley, “There is a great need for seafloor seismology. Any device that goes out to sea, even if it is only 50 kilometers before the coast, would be very useful. ”
Scientists hope to use dense fiber-optic networks around the world, spanning more than 10 million kilometers under land and sea, to measure sensitive seismic activities on Earth.
“This is actually a study on the seismology front, the first time anyone has used an offshore fiber-optic cable for viewing or imaging fault structures of such oceanic signals. Vacant locations in seismic networks around the world “Oceans,” said study co-author Jonathan Ajo-Franklin from Rice University in the US.