In California, thousands of miles of fiber optic cables crisscross the state, providing people with internet. But these underground cables can also have a surprising secondary function: they can sense and measure earthquakes. In a new study at Caltech, scientists report using a section of fiber optic cable to measure intricate details of a magnitude 6 earthquake, pinpointing the time and location of four individual asperities, the "stuck" areas of the fault, that led to the rupture.
