How Distributed Acoustic Sensing works (IMAGE) Norwegian University of Science and Technology Caption This schematic shows how the Distributed Acoustic Sensing, called DAS, works. A laser pulse is sent from the shore station through a fibre optic cable by an interrogator (a). The fibre has evenly spaced nodes on it, called defects (b). Underwater sounds cause the defects in the fibre to be slightly displaced, which delays the backscatter a signal back to the interrogator, which then interprets the time delay as a strain on the fibre. That in turn can be interpreted as acoustic data. Credit Graphic: Marte Finsmyr/Léa Bouffaut Usage Restrictions Only in association with articles about this research and with proper credit. License Original 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.