Indian Tsunami Early Warning Centre (ITEWC) at Indian National Centre for Ocean Information Services (INCOIS), here in Hyderabad, has detected 716 earthquakes since its inception till date, including 103 in the Indian Ocean and 613 in other oceans.
The centre operational since October 2007 was established in response to the tsunami in December 26, 2004, by the Ministry of Earth Sciences (MoES). It has been making use of advanced technology and scientific models to provide initial warning of within 10 minutes of a quake of more than 6.5 on the Richter Scale of the Indian Ocean with 100% probability, said INCOIS group director – Ocean Modelling, Applied Research and Services (OMARS) T. Balakrishnan Nair.
Mr. Nair told the annual conference of relief commissioners and disaster management secretaries organised by the Home Ministry on ocean and coastal multi-hazards few days ago, that there are chiefly two sources of a likelihood of a tsunami hitting the Indian coasts.
On the west coast, it could arise from the Makran subduction zone in the southern offshore of Iran and Pakistan when a quake occurs and where the travel time by the time it hits the Gujarat coast will be about two to three hours. The other potent zone is Nicobar islands on the east coast where the Andamans and Nicobar Islands are likely to be hit by a tsunami within 30-40 minutes of a quake in the Indian ocean. From there it could take two to three hours before its strikes the mainland, he explained.
INCOIS has been working on building resilient coastal communities since most coastal areas are low lying and vulnerable to oceanogenic disasters such as tsunamis, storm surges and sea-level rise. Four kinds of alerts are being issued — Red (warning), Orange (alert), Yellow (watch) and Green (threat passed) — depending on the seriousness of the threat to lives and property starting with total evacuation of the vulnerable population to a clear signal through a common alerting protocol prepared by the National Disaster Management Authority (NDMA) to warn people during emergencies.
Alerts could be issued through fax, mail, web, SMS, satellite communication and through the public address system on the ground to alert the coastal rural communities. These warnings are based out of the observations recorded by the buoys, tide gauges and other equipment on the ocean.
Close to a dozen buoys collect and transmit high resolution real-time upper ocean profiles of temperature, salinity and currents, surface meteorological data like winds, humidity, pressure, temperature, rainfall and radiation and wave parameters from Bay of Bengal and the eastern Arabian Sea, he said.
Ocean state forecasts are being issued three to five days in advance for high swells and storm surges for the benefit of the shipping industry, Indian Navy, ports/harbours, oil and gas exploration companies along with a special advisory for small vessels to prevent capsizing in the high seas 10 days in advance.
Indigenously-developed Search and Rescue Aid Tool (SARAT) has helped the Coast Guard to find the body of a fisherman within the highest probability area predicted by the model based on geographical information systems, wind speeds and ocean currents to predict trajectories.
About nine lakh fishermen across both the coasts are not only beneficiaries of these forecasts and warnings, but they are also given information about the probable fishing sites through special advisories, he pointed out. The institute had generated coastal multi-hazard vulnerability assessment maps representing coastal flooding by extreme events in a 100-year return period considering the implications of future sea-level rise.
The socio-economic risk assessment up to building level within these flood zones was assessed as a resilience measure and a dedicated 3D visualization application was developed to view and analyse the data. A Coastal Vulnerability Atlas covering the Indian coast comprising 156 maps on 1:1 lakh scales too was prepared, he added.
