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

Hydroacoustics is one of the four monitoring technologies of the Internatio nal Monitoring System (IMS) established tinder the Comprehensive Nuclear-Te st-Ban Treaty (CTBT). The hydroacoustic network, designed to monitor the ma jor world oceans, contains eleven stations located with an emphasis on the vast ocean areas of the Southern Hemisphere. Two different sensing techniqu es are employed, hydrophone sensors, which effectively cover large ocean ar eas, bill are quite complex and expensive, and seismic detectors on small i slands which are less effective, but considerably simpler and cheaper The h ydroacoustic stations transmit data in real time via satellite to the Inter national Data Centre (IDC). The IDC analyses the hydroacoustic data in comb ination with the other three technologies to produce bulletins of detected events for the States Party to the Treaty.