There are more than one million kilometers of fibre optic cable running across the ocean floor. Clever seismologists have figured out a way to put them to another use.
Seismologists at Caltech working with techies at Google have developed a method of using existing underwater telecommunication cables to improve earthquake and tsunami warning systems around the world.
The vast network of fibre optic cables at the bottom of Earth’s oceans represents the backbone of international telecommunications and scientists have long tried to figure out a way to use this network of submerged cables to monitor seismicity. With three quarters of our planet covered by water, it's extremely difficult and expensive to install, monitor, and run underwater seismometers to keep track of the earth’s movements beneath the seas.
Wouldn't it be good news if we could monitor seismicity by making use of the infrastructure already in place along the ocean floor? Happily, Zhongwen Zhan, PhD, assistant professor of geophysics at Caltech, and his colleagues have come up with a way to analyze the light traveling through “lit” fibers - in other words, existing and functioning submarine cables - to detect earthquakes and ocean waves without the need for any additional equipment, as described in the journal Science.
“This new technique can really convert the majority of submarine cables into geophysical sensors that are thousands of kilometers long to detect earthquakes and possibly tsunamis in the future,” says Zhan. “We believe this is the first solution for monitoring seismicity on the ocean floor that could feasibly be implemented around the world. It could complement the existing network of ground-based seismometers and tsunami-monitoring buoys to make the detection of submarine earthquakes and tsunamis much faster in many cases.”