Monterey Bay Seafloor Experiment (IMAGE) University of California - Berkeley Caption Researchers employed 20 kilometers (pink) of a 51-kilometer undersea fiber-optic cable, normally used to communicate with an off-shore science node (MARS, Monterey Accelerated Research System), as a seismic array to study the fault zones under Monterey Bay. During the four-day test, the scientists detected a magnitude 3.5 earthquake 45 kilometers away in Gilroy, and mapped previously uncharted fault zones (yellow circle). Credit Nate Lindsey, UC Berkeley Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.