Sonardyne International has delivered the latest batch of acoustic monitoring sensors that will oversee the Indian coastline by providing the early detection and warning of tsunami waves. The network of new sensors will be deployed alongside the existing Sonardyne sensors in the Bay of Bengal and off the west coast off India where they will continuously monitor the ocean for the characteristic water pressure changes that indicate a developing tsunami.
The Sonardyne monitors are based upon subsea transponders equipped with highly accurate pressure sensors that are positioned on the seabed hundreds of miles off the Indian coast. If one of the transponders detects a small, but continuous, change in water pressure it transmits an acoustic emergency warning signal to a radio buoy moored on the surface above it. The buoys are operated by NIOT (National Institute of Ocean Technology) of Indiaand they relay the warnings via a satellite link to the organisation's headquarters in Chennai. From there, alerts can be forwarded to the appropriate authorities in time for precautions to be taken.
The contract for a tsunami detection system for India was awarded to Sonardyne following an initial trial early in 2007 when systems from Sonardyne and three other manufacturers were evaluated. Only the Sonardyne sensors performed satisfactorily so the company was asked to supply a further eight monitoring transponders which were installed to provide immediate coverage for the areas at most risk. The latest delivery of sensors completes the Indian early warning network and now provides monitoring for India's entire coastline.
The reliability of the Sonardyne detection system was convincingly demonstrated to NIOT when the first sensors had only just been laid. The NIOT ship Sagar Manjusha was returning to Chennai after the deployment of six tsunami buoys. When the ship was an hour from port, one of the Sonardyne sensors it had just laid registered a tsunami warning, triggering an alert to NIOT. The vessel was prevented from entering the harbour for berthing and all vessels in Chennai port were evacuated as a precaution. Although a dangerous tsunami did not develop, it was felt that the Sonardyne system had proved its reliability and effectiveness.