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The 2004 Indian Ocean Earthquake and Tsunami
Context:
The 20th anniversary of the 2004 Indian Ocean earthquake and tsunami marks a significant moment in understanding seismic hazards and improving disaster management.
Event Overview:
- On December 26, 2004, a powerful undersea megathrust earthquake with a magnitude of 9.1-9.3 struck off the coast of the Indonesian island of Sumatra, making it the third-largest earthquake in recorded history.
- It originated 30 kilometres below the ocean floor in the Sunda Trench, where the Indo-Australian plate subducts beneath the Burma microplate, part of the Eurasian plate.
- The event ruptured approximately 1,300 kilometres of the fault, from Sumatra in the south to the Coco Islands in the north.
Unprecedented Impact:
- The tsunami affected 17 countries, across the Indian Ocean basin, from Indonesia to the east coast of Africa.
- Including Indonesia, Bangladesh, India, Malaysia, the Maldives, Myanmar, Singapore, Sri Lanka, and Thailand.
- The tsunami caused over 227,000 deaths and displaced 1.7 million people, marking it as the deadliest tsunami in history.
- Tsunamis can trigger a range of secondary hazards, including flooding, coastal erosion, and the spread of mosquito-borne diseases, particularly in vulnerable coastal regions.
Scientific Response & Developments Post-2004:
- The tsunami’s unexpected reach surprised scientists, as there were no previous events of such magnitude along India’s eastern coast. Two major tsunamis occurred in 1881 and 1883, but they were far less impactful.
- Indian Tsunami Early Warning Centre (ITEWC) was established in 2007 to enhance disaster preparedness. Located at the Indian National Centre for Ocean Information Services (INCOIS), Hyderabad.
- Utilises seismological stations, pressure recorders, and tidal stations across the Indian Ocean. Provides tsunami alerts within 10 minutes of identifying potential earthquake threats.
- India became the fifth country in the world to have such an advanced system, after the U.S., Japan, Chile, and Australia.
- Utilises seismological stations, pressure recorders, and tidal stations across the Indian Ocean. Provides tsunami alerts within 10 minutes of identifying potential earthquake threats.
UNESCO’s Global Response:
- Global Tsunami Warning System: UNESCO has helped establish the GTWS, covering the Pacific, Indian Ocean, Mediterranean, Caribbean, and North-East Atlantic.
- The system incorporates rapid detection technologies, seismic and sea-level monitoring, and real-time data sharing to quickly alert coastal communities.
- By 2031, UNESCO aims to confirm tsunamis within 10 minutes or less for the highest-risk coastlines.
- The system incorporates rapid detection technologies, seismic and sea-level monitoring, and real-time data sharing to quickly alert coastal communities.
- Cutting-Edge Research and Technologies: UNESCO has invested in seabed mapping, deep-ocean technologies, buoy systems, and hazard assessments to improve understanding of tsunami risks and strengthen predictive capabilities.
- Tsunami Ready Initiative: Emphasises community preparedness and has already involved 32 countries. The goal is to certify 100% of at-risk communities by 2030.
- The initiative includes public education, hazard mapping, evacuation planning, and annual simulation drills to strengthen awareness and readiness in vulnerable coastal areas.
Potential Future Risks and Research:
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- Experts warn about the potential for future large tsunamis from regions like the Makran Coast and the Myanmar coast, which could affect India’s west coast, including Mumbai.
- Nuclear Plant Vulnerability: The tsunami’s impact on the Kalpakkam nuclear power plant raised concerns about the vulnerability of nuclear facilities to such natural disasters. While the plant survived the tsunami, it was shut down automatically due to rising water levels and no radioactive releases.
- Geophysical Insights: Research into “slow slips” and premonitory seismic activity has enhanced the understanding of earthquake precursors and the processes involved in large earthquakes.
Actions for Tsunami Preparedness:
- Financing for Disaster Preparedness: Investing in preparedness is more cost-effective than spending on post-disaster recovery.
- The ESCAP Trust Fund and other donors continue to play a crucial role in financing tsunami and climate-related preparedness, with a focus on community engagement and disaster risk reduction.
- Regional Cooperation is essential for effective disaster management, enabling countries to share data, resources, and best practices.
- In the North-West Indian Ocean, India, Iran, Pakistan, UAE, and Oman have developed a unified Probabilistic Tsunami Hazard Assessment to enhance risk-informed decision-making, including evacuation planning and national tsunami warning systems.
- Addressing Gaps in Tsunami Warning Systems: A seamless, end-to-end tsunami warning system is crucial, covering both upstream (e.g., detection) and downstream (e.g., response) components.
Countries need to identify gaps and ensure climate actions are tailored to local needs, fostering transboundary cooperation.
