According to new research, the large number of undersea cables that transmit data around the world could one day be used to track earthquakes and tsunamis.
During a test run last year, one of the fiber-optic cables of American tech giant Google was able to successfully pick up on nearby earthquakes by detecting variations in the cable. It’s a new approach to an idea that researchers have been working on for the past several years.
“Can we find a less expensive way to cover the ocean with geophysical sensors? There’s already this telecommunication cable infrastructure out there. If you can turn them into sensors, that’s wonderful — and that’s what we’re doing now,” says Zhongwen Zhan, an assistant professor of geophysics at the California Institute of Technology and lead author of the research.
Data transmission and early warnings
On top of their main job of sending data all over the world, these cables could one day send early warnings to people on shore when a tsunami is coming their way. They could also give seismologists and geophysicists a closer look at earthquakes that occur underwater.
The novel approach doesn’t even require installing any new equipment to the existing web of more than a million kilometers of fiber optic cables that cut across the seafloor.
Between December 2019 and September 2020, Mr. Zhan’s research team documented roughly 20 moderate to large earthquakes using Google’s 10,500-kilometer-long cable named Curie. The cable was also able to pick up swells in the ocean caused by storms. That suggests the technique can also be used to spot tsunamis, which earthquakes can trigger.
The ability to see tsunamis while they’re still far from shore could save lives. Beyond having a better view of the ocean than the small number of existing sensors specifically designed to look for tsunamis, fiber optic cables can also send warnings to shore much faster, perhaps in a matter of milliseconds, according to Google.
“We’re humbled and excited by the possibility of collaborating with the optical, subsea and seismic research communities to use all of our cable infrastructure for greater societal benefits,” Google wrote in a blog last year, shortly after the company had reached out to Mr. Zhan to further develop the new approach to seismic sensing on the seafloor.
“We hope this new approach can really give people a better chance of catching those events early on, so that people have more time to react,” Mr. Zhan says.