SOSUS - Sound Surveillance Underwater System - (USA/N.A.T.O.)

A passive seabed hydrophone network, put in place to detect (and help intercept) Soviet Submarines and Surface Vessels. Established in 1952 under cover name CAESAR. Initially linked to shore monitoring stations known as NAVFACs (Naval Facilities Engineering Command) and part of the later IUSS (Integrated Undersea Surveillance System). Since the end of the Cold War, SOSUS has been largely automated and computerized, with the ability to come into operational service at short notice. Also used to detect marine animals and underwater seismic activity linked to such issues as Global Warming. SOSUS stations were initially arrayed along the Eastern seaboard of the USA and at NAVFAC Brawdy in Wales (De-commissioned 1995).