Lawrence Livermore Lab researchers harness fiber optic networks to monitor earthquakes

LIVERMORE, Calif. (KGO) -- Earthquakes are a fact of life in California. And now, a local research team is developing a better way to track them and possibly better understand the forces at work. They say the key is something you may have in your own home.

If you've lived in California for any length of time, you've probably felt the powerful jolt of a sudden earthquake or maybe watched the wild movements of an active seismograph.

But now, researchers at the Lawrence Livermore National Laboratory believe they have a cheaper and potentially more powerful way to monitor seismic activity.

"Yeah. Back in March, we had an earthquake in the Dublin Hills, and so what you're seeing here is here is an image captured on the fiber," said Seismologist Gene Ichinose, Ph.D.

Ichinose showed us the footprint of a recent 3.9 magnitude earthquake in the East Bay. It was captured, not by a traditional seismograph, but the kind of fiber optic cable that might carry anything from your internet service to a simple phone call. In this case, it was an unused line running 50 miles between Moscone Center in San Francisco and Sunnyvale. At one end, Ichinose and his collaborators plugged in a box shaped device known as an "interrogator."

"It's about the size of a microwave, and we just plug it into a telecommunications port. You turn it on, the interrogator sends a pulse of light down the fiber and records the backscatter," Ichinose said.

He said it's the equivalent of listening in as ground movement jostles the cable along with the fiber optic light running through it. To help demonstrate, computer scientist Tim Brandt strung a similar line through the lab's hallway then went for a stroll. Even the faint vibrations of his footsteps on the carpet were enough to register.

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The team envisions a scalable network that could reach almost anywhere in the world covered by fiber optic communication cables, including the ocean floor. The kind of remote, but seismically active areas that can trigger deadly tsunamis and offshore earthquakes.

"It could be set up pretty much anywhere else, provided that we worked it out with the particular owner of those networks to be able to connect into their network, but it doesn't disrupt their network," Brandt said.

Ichninose adds that the real power comes with scale, the kind of data that researchers spend years trying to collect in areas like Parkfield, along the San Andreas fault.

"It takes a lot of resources, people and money to site a seismometer and dig a hole and couple it to the earth. We've been using the same old technology for the last century. It's your traditional seismometer, and what fiber optic distributed sensing allows us to do is turn ordinary fiber optic cables that are used for telecommunications into thousands of virtual sensors," he said.

The Livermore team also believes fiber optic networks could also be used as a early warning system, or even to monitor stress levels on key structure like dams and roadways.