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

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