Optical internet cables could act as sensors to detect earthquakes

“We can continuously listen to – and hear well – the Earth using preexisting optical fibre that have been deployed
for telecom purposes,” said Biondo Biondi, a professor at Stanford. Currently researchers monitor earthquakes with seismometers, which are more sensitive than the proposed telecom array, but their coverage is sparse and they can be challenging and expensive to install and maintain, especially in urban areas.

By contrast, a seismic observatory proposed by the researchers would be relatively inexpensive to operate. “Every meter of optical fibre in our network acts like a sensor and costs less than a dollar to install,” Biondi said. “You will never be able to create a network using conventional seismometers with that kind of coverage, density and price,” he said.

Such a network would allow scientists to study earthquakes, especially smaller ones, in greater detail and pinpoint their sources more quickly than is currently possible. Greater sensor coverage would also enable higher resolution measurements of ground responses to shaking.

“Civil engineers could take what they learn about how buildings and bridges respond to small earthquakes from the
billion-sensors array and use that information to design buildings that can withstand greater shaking,” said Eileen
Martin, a graduate student in Biondi’s lab.