There are described methods, systems, and computer-readable media for detecting events in a conduit. A first length of optical fiber, positioned alongside the conduit, is interrogated to obtain interferometric data from the first length of optical fiber. A second length of optical fiber, positioned alongside the conduit, is interrogated to obtain interferometric data from the second length of optical fiber. The interferometric data obtained from the first length of optical fiber is compared with the interferometric data obtained with the second length of optical fiber. Based on the comparison, whether an event has occurred in the conduit is determined.