2 decades on: Strides in warning systems
In the realm of disaster management, India stands tall as a global leader, thanks to its state-of-the-art Tsunami Early Warning System (TEWS) established in the wake of the devastating Indian Ocean tsunami that crashed ashore two decades ago to this day.
The tsunami of December 26, 2004, which claimed over 2,30,000 lives across 14 countries, served as a wake-up call for the global community. India, with its vast coastline stretching over 7,500 km, bore significant losses. In response, the government established the Indian Tsunami Early Warning Centre under the Indian National Centre for Ocean Information Services in Hyderabad. Operational since 2007, this centre is now a cornerstone of India’s disaster preparedness infrastructure.
The Indian TEWS is a complex network of seismic sensors, deep-ocean pressure recorders, wave rider buoys, tide gauges, and satellite-based communication systems. It operates by detecting undersea earthquakes in real-time, analysing their potential to generate tsunamis, and disseminating alerts to vulnerable regions.
It employs a four-step approach:
1. A network of seismic stations continuously monitors tectonic activity in the Indian Ocean and beyond.
2. Advanced computer models simulate tsunami propagation and predict the likely impact on coastal areas.
3. Many instruments like wave rider buoys, bottom pressure recorders and tide gauges are installed in the Indian Ocean to monitor the trajectory of tsunami and collect wave parameters associated with it.
4. Alerts are rapidly communicated to disaster management authorities and the public through SMS, emails, television, radio, and social media.
What sets India’s TEWS apart is its use of cutting-edge technology and international collaboration. The system integrates data from global seismic networks and partners with agencies such as the Pacific Tsunami Warning Center and the Japan Meteorological Agency (JMA). India’s indigenous Deep-Ocean Assessment and Reporting of Tsunamis buoys are pivotal in detecting changes in ocean pressure.
Since its inception, the TEWS has successfully issued timely warnings for multiple undersea earthquakes, ensuring swift evacuation and mitigation of risks. Notably, during the 2012 Banda Aceh earthquake, the system accurately predicted the non-occurrence of a tsunami.
India’s TEWS is not just a national asset but also a regional lifeline. Designated as a Regional Tsunami Service Provider by Unesco’s Intergovernmental Oceanographic Commission, it provides critical advisories to 25 Indian Ocean Rim countries.
But challenges remain. Normally, tsunamigenic earthquakes happen in plate tectonic boundaries. In the Indian Ocean, we have two different sources: one near Sumatra and one near Makran. Literature studies reveal during 1945, we had a tsunami from Makran. But tsunamis in the Pacific ocean suggest tsunamigenic earthquakes also happen beyond tectonic plate boundaries, particularly at the middle and tail end of plates due to realignment.
Are we well equipped to predict those? Though tsunamis are primarily associated with earthquakes, it can also happen due to landslides, meteorite impact and nuclear explosions. Whether our system is capable of predicting those is the question that we raise during the 20th anniversary.
Besides, there are many natural precursors like the initial withdrawal of the ocean, sound in the ocean, a special smell happening just before a tsunami. Moreover, there are many animal precursors, which include shifting of marine animals to land and non linear behavior of animals.
Enhancing public awareness, improving last-mile connectivity for warning dissemination, and conducting regular drills are essential to ensure the system’s effectiveness. Additionally, addressing the impacts of climate change, such as rising sea levels and increasing coastal vulnerabilities, requires sustained efforts.
The advancements made by the Indian scientific team in the last 20 years should be applauded. Our advanced tsunami warning system underscores the power of technology in saving lives. By investing in robust infrastructure and fostering international partnerships, India has set a global benchmark for disaster preparedness.
Many other countries also possess effective tsunami warning systems. Japan, the US, Indonesia, Chile, Australia and New Zealand have effective warning systems.
Japan’s tsunami early warning system is among the most advanced in the world, owing to the country’s vulnerability to seismic activities. The National Oceanic and Atmospheric Administration leads the TEWS in the US, with a focus on both the Pacific and Atlantic coasts. Indonesia is situated along the Pacific Ring of Fire, making it one of the most tsunami-prone countries. The Indonesian Agency for Meteorology, Climatology, and Geophysics manages the TEWS.
Chile has developed a robust TEWS managed by the National Emergency Office of the ministry of interior and the Hydrographic and Oceanographic Service of its navy. Australia’s Joint Australian Tsunami Warning Centre, operated by its Bureau of Meteorology and Geoscience, provides warnings for the Indian Ocean and Pacific Ocean regions. New Zealand’s warning system is managed by its ministry of civil defence and emergency management.
So it’s a responsibility rightly shouldered by a number of countries in the region. Along with that responsibility comes the motivation to constantly improve the individual and collaborative systems.
Praveen Sakalya
Head, Department of Physics, St Thomas College, Pathanamthitta; former project scientist, National Centre for Coastal Research, Chennai
(Views are personal)