The SOund SUrveillance System, or SOSUS, is a fixed component of the U.S. Navy's Integrated Undersea Surveillance Systems(IUSS) network used for deep ocean surveillance during the Cold War. Installation of SOSUS was begun in the mid 1950s by the U.S. Navy for use in antisubmarine warfare. SOSUS consists of bottom mounted hydrophone arrays connected by undersea communication cables to facilities on shore. The individual arrays are installed primarily on continental slopes and seamounts at locations optimized for undistorted long range acoustic propagation. The combination of location within the oceanic sound channel and the sensitivity of large-aperture arrays allows the system to detect radiated acoustic power of less than a watt at ranges of several hundred kilometers. In October, 1990, the Navy granted approval to NOAA/PMEL to access the SOSUS arrays in the North Pacific to assess their value in ocean environmental monitoring,as part of the U.S. government's dual-use initiative. The data collection systems developed by NOAA's VENTS Program have been in place since August 29, 1991. Acoustic signals from the north Pacific Ocean are monitored and recorded at the Newport, Oregon facility of NOAA/PMEL. This is the primary tool for both continuous monitoring of low-level seismicity around the northeast Pacific Ocean and real-time detection of volcanic activity along the northeast Pacific spreading centers in support of the VENTS research program in ocean hydrothermal systems. Real-time ridge crest monitoring potentially permits the timely on-site investigation of hydrothermal and magmatic emissions. Data acquisition is accomplished by combining portions of the Navy's processing facilities with NOAA-designed systems installed at the U.S. Naval Ocean Processing Facility (NOPF) at Whidbey Island, Washington. Analog outputs from each hydrophone element are available either through direct cabling or remote data linkage. Navy systems perform adaptive beam forming on digitized hydrophone signals, with the outputs converted back to analog electrical signals. These analog hydrophone and beam-former outputs are accessed by the NOAA-supplied systems, where the signals are low-pass filtered, digitized, and temporarily buffered on hard disk. The digital data are provided to a wide-area network (WAN) based on Network File System (NFS) protocol, linking (by encrypted, dedicated telephone line) the acquisition computer to an analysis system located at NOAA laboratories in Newport, Oregon. For more information on U.S. Navy SOund SUrveillance System (SOSUS)see: "http://newport.pmel.noaa.gov/geophysics/sosus_system.html" Address inquiries to: Chris Fox - Principal Investigator NOAA/PMEL OSU Hatfield Marine Science Center 2115 S.E. OSU Drive Newport, Oregon 97365 USA VOICE: (541) 867-0276 FAX: (541) 867-0356 Email: fox&#64pmel.noaa.gov
SOSUS
Acoustic Sounders