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Tsunami and Storm Surge Early Warning System for Community Preparedness
Overview
The great Sumatra earthquake (Mw 9.3) of 26th December 2004, was rated as the world’s second-largest recorded earthquake. This earthquake generated a devastating tsunami, which caused unprecedented loss of life and damage to property in the Indian Ocean rim countries. The Tsunami was considered one of the deadliest natural hazards in history, killing over 230,000 people in fourteen countries. In India, it claimed 10,450 lives according to official estimates. Responding to this disaster, the Government of India felt the need for a technology-led adaptive measure for Tsunamis and Storm Surges.
In this direction, the Ministry of Earth Sciences (MoES), Government of India, established the Indian Tsunami and Storm Surge Early Warning System (ITEWS) to provide tsunami warnings across the country. A dedicated Indian Tsunami Early Warning Centre (ITEWC) was formed in October 2007 at the Indian National Centre for Ocean Information Services (INCOIS), an autonomous body under the Ministry of Earth Sciences, to support and monitor the operations of the ITEWS.
Vision: To provide timely tsunami and storm surge advisories to the stakeholders to mitigate the disaster.
Objectives
y To detect, locate, and monitor the potentially tsunamigenic events occurring in the Indian Ocean
Basin and provide timely tsunami advisories to the Indian and Indian Ocean rim countries. y To forecast and provide Storm Surge advisories with storm surge heights and inundation extent along the Indian coast. y To improve the coastal community’s preparedness for tsunami emergencies, minimize the loss of life and property and ensure a structural and systematic approach to building community preparedness.
Stakeholders Involved
The Ministry of Earth Sciences (MoES), National Disaster Management Authority (NDMA), Ministry of Home Affairs (MHA), Indian Metrology Department (IMD), State and Union Territory Disaster Management Authorities, State and District EOCs, ports, harbours, Navy, Coast Guard, NDRF, Critical Installations (Energy, Oil Sectors, etc.) and coastal communities. Solution and Implementation
The Indian Tsunami Early Warning System (ITEWS) was established with a real-time network of seismic stations, Tsunami buoys, tide gauges and 24 X 7 operational Warning Centre to detect tsunamigenic earthquakes/events, monitor tsunamis and provide timely advisories to vulnerable communities. It deploys the latest communication methods with back-end support of a pre-run model scenario database and a comprehensive Decision Support System (DSS).
The Warning Centre is capable of issuing Tsunami bulletins in less than 10 minutes after any major earthquake in the Indian Ocean thus providing a response time of about 10 – 20 minutes for near source regions (Andaman & Nicobar region) and a few hours in the case of far-source regions (Indian mainland). INCOIS is the nodal agency to provide the Storm surge Early Warning advisories with expected storm surge heights and extent of inundation along the Indian coast during any cyclonic event. A dedicated website with responsive web frameworks is in place to make information accessible to the stakeholders and public.
ITEWC receives seismic data from about 17 national and 400 global seismic stations in real-time. The seismic data is fed to an earthquake auto location software application built around GIS capabilities to render earthquake-related maps, waveform traces and spectra. ITEWC is capable of auto-locating all earthquakes of >5 M within 5 – 10 minutes of their occurrence. The Sea level observations from Tide gauges and tsunami buoy networks are crucial to confirm the tsunami generation and predict the tsunami hazard for the coastal locations where the tsunami wave has yet to strike.
Every coastal forecast zone in the spatial data (representing a district/group of islands) is provided with attributes such as Estimated time of arrival (ETA), Estimate Maximum Wave Amplitude (EWA) and Threat Category. Observations of positive wave amplitude and time at tide gauge stations are also included in the bulletins.
The detailed tsunami bulletins are issued in both text and graphical formats to stakeholders along with GISbased maps such as tsunami threat Maps, directivity Maps, and Travel time maps, which are useful to the disaster mitigation teams to act swiftly. Spatial datasets are also made available to download. The Centre disseminates tsunami bulletins to various stakeholders through multiple dissemination modes simultaneously (Website, SMS, Emails, Fax, GTS etc.).
The Implement Tsunami Ready programme initiated by the Intergovernmental Oceanographic Commission (IOC) of UNESCO is aimed at promoting tsunami preparedness through the active collaboration of the public, community leaders, and national and local emergency management agencies. As per the regional guidelines, each community is expected to fulfil 11 important indicators to minimize the loss of life and property and ensure a structural and systematic approach to building community preparedness – thus, to be Tsunami Ready. To implement and monitor these Tsunami Ready indicators, GIS played a pivotal role in the generation of
