What is a Tsunami?

• A tsunami is a series of powerful ocean waves typically caused by sudden underwater disturbances such as earthquakes, volcanic eruptions, landslides, or, rarely, asteroid impacts.
• The term originates from the Japanese words “tsu” (harbor) and “nami” (wave). 
  • Unlike ordinary waves generated by wind, tsunamis result from a large-scale displacement of water, giving them immense energy and long wavelengths that allow them to travel across entire ocean basins at jet-like speeds of up to 800 km/h.

Risk of Tsunami

• Tsunamis pose a grave threat to coastal regions globally, especially around tectonically active zones such as the Pacific Ring of Fire. 
  • The 2004 Indian Ocean tsunami, triggered by a 9.1 magnitude earthquake, caused over 227,000 deaths across 14 countries. 
• Tsunami risks are amplified by factors such as high population density in coastal zones, inadequate infrastructure, and lack of public awareness.
• The impacts include destruction of ecosystems, loss of life and livelihoods, economic setbacks, and long-term health consequences due to water contamination and displacement.

NDMA Guidelines for Tsunami Management

• Risk Assessment and Mapping: Coastal zones must be identified based on vulnerability to tsunami waves using historical data and GIS tools.
• Strengthening Warning Systems: Integration of seismic data, tide gauges, and bottom pressure recorders to issue timely alerts.
• Community Preparedness: Conduct regular mock drills, public awareness campaigns, and training for local response teams.
• Infrastructure Resilience: Promote tsunami-resistant buildings, clear evacuation routes, and signage in high-risk areas.
• Interagency Coordination: Establish coordination mechanisms at national, state, and district levels through disaster management authorities.
  

Initiatives to Improve Preparedness

• National – Indian Tsunami Early Warning System (ITEWS): Established in 2007 at INCOIS, Hyderabad, it issues advisories within 10 minutes of seismic events and serves 28 Indian Ocean countries.
• Global – Pacific Tsunami Warning Center (PTWC): Founded in 1949 in Hawaii, it monitors Pacific-wide seismic activity and issues tsunami alerts.
• UNESCO-IOC Tsunami Ready Programme: Promotes community-level resilience through preparedness indicators; Indian villages like Venkatraipur and Noliasahi have been recognized.
• Indian Ocean Tsunami Warning and Mitigation System (IOTWMS): A regional coordination effort set up post-2004 under UNESCO to standardize alerts and response across Indian Ocean rim nations.