Lasers, fiber optics and tiny vibrations tease a way to warn about earthquakes

Scientists were able to use the data from a fiber optic cable and a sensitive measuring device to “image” the Mendocino earthquake.

When the Mendocino earthquake ruptured off the California coast in 2024, it shook houses off their foundations, sent a 3-inch tsunami racing toward shore and touched off a fascinating science experiment — in the server room of a local police station, of all places.

More than two years before the quake, scientists installed a device called a “distributed acoustic sensing interrogator” at the Arcata Police Station near the coast. The device fires a laser through the fiber optic cables that provide the station with internet service and senses how some of that laser light quivers or bends as it returns to its source.

Now, in a study published Thursday in the journal Science, researchers announced that they were able to use the data from the fiber optic cable to “image” the Mendocino earthquake — determining the magnitude, location and length of the rupture.

The study shows how scientists can essentially turn fiber optic cables into seismometers that return detailed data about earthquakes at the speed of light. Outside scientists said this fast-developing technology could drastically improve earthquake early-warning systems, giving people more time to seek safety, and could be key to predicting catastrophic earthquakes in the future, if that’s possible.

“This is the first study that’s imaging an earthquake rupture process from an earthquake that’s this large,” said James Atterholt, a research geophysicist at the United States Geological Survey, and the first author of the new study. “This shows that there’s potential to improve earthquake early warning alerts with telecom fibers.”