Hydroacoustic monitoring system for the Comprehensive Nuclear-Test-Ban Treaty

Hydroacoustics is one of the four monitoring technologies of the International Monitoring System (IMS') established under the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The hydroacoustic network, designed to monitor the major world oceans, contains eleven stations located with an emphasis on the vast ocean areas of the Southern Hemisphere. Two different sensing techniques are employed; hydrophone sensors, which effectively cover large ocean areas, but are quite complex and expensive, and seismic detectors on small islands which are less effective, but considerably simpler and cheaper. The hydroacoustic stations transmit data in real time via satellite to the International Data Centre (IDC). The IDC analyses the hydroacoustic data in combination with the other three technologies to produce bulletins of detected events for the States Party to the Treaty.