KOCHI: Twenty years ago — on December 26, 2004 — deep beneath the Indian Ocean near the island of Sumatra, a 1,300km-long rupture occurred on the faultline between the Burma and India tectonic plates.
The Indian plate’s edge lies beneath the Burma plate. Due to a build-up of tension, a slip occurred on the boundary about 30km below sea leavel. The time was 7.59am (6:28am IST) at Banda Aceh, Northern Sumatra, in Indonesia when this tectonic shift occurred.
As is often the case with tectonic movement, this slip triggered an earthquake. It was no ordinary quake. With a magnitude of 9.1 on the Richter Scale, it was recorded as the third-largest earthquake since 1900. It lasted for about 10 minutes. Tremors were felt in neighbouring countries, including India.
Within minutes, enormous waves — rising as high as 51m — began crashing against the coasts of Sumatra. The ensuing seven hours were terrifying. Like a nightmare.
News channels across the world started flashing a phenomenon that the modern world had not heard much of: tsunami. In Japanese, the word means ‘harbour wave’ – ‘tsu’ meaning harbour and ‘nami’, wave. Sounds harmless. But that isn’t the case.
Within 90 minutes, the waves reached the Indian shores, devastating coastal communities in the Andaman and Nicobar Islands, Kerala, Tamil Nadu, Puducherry, and Andhra Pradesh.
Though the tidal intensity had waned by then, the waves were still nine metres high — more than enough to wreak havoc on a coastline that, at the time, lacked warning systems and quick-evacuation action plans.
It was the day after Christmas. Kerala woke up from holiday slumber to the grim news of hundreds of deaths.
The tsunami’s global death toll was 2,30,000. Over 10,000 Indians perished. In Kerala, where the tsunami’s destructive force swept across the shores of Kollam, Alappuzha, and Ernakulam, 171 lives were lost, including 132 in Alappad village of Kollam alone.
U Ullas, Alappad’s current panchayat president, was 18 at the time. He still remembers the day that upended many lives and altered the coastline. “Suddenly, the sea retreated. That’s the first thing I remember,” he says.
The retreating sea piqued the local residents’ curiosity, drawing many, including children, into the now-dry seabed. In some time, albeit late, warnings reached the community.
People ran helter-skelter for safety. But the towering waves struck swiftly. “We lost more than a hundred lives. The water that lashed the land retreated within 10 minutes, but by then, thousands of houses were swallowed by the sea,” Ullas says.
The waves also claimed a large chunk of land. “We couldn’t even distinguish between the lake and the sea,” Ullas recalls.
He adds that until that day, neither he nor anyone in his village had heard the word ‘tsunami’. “Now, we can, and will, never forget it,” he says.
In Ernakulam’s Vypeen, the waves hit later that afternoon. Abhilash, a fisherman from Edavanakkad panchayat on the island, was 22 at the time. “First, it was just the water level rising and homes slowly getting flooded. As far as I remember, the high waves struck later,” he says.
“Back then, we used to watch films together on Sundays in nearby homes — two or three families together. That Sunday, water entered our homes. Fortunately, most people moved to relief camps. We, however, lost about five people when the waves came. It was 20 years ago; the day is like a blur in my mind.”
Vypeen also lost part of its shore and many homes. Over the years, many residents have moved farther from the sea. The remnants of a few abandoned homes are still visible along the coast, alongside the large sea wall destroyed by the tsunami, still awaiting repair.
For India, the 2004 tsunami was a wake-up call, sparking a major project to enable disaster prediction and warning. “After the event, the Indian National Centre for Ocean Information Services (INCOIS) worked to establish the Tsunami Early Warning System (TEWS) to provide timely tsunami advisories,” says INCOIS director T M Balakrishnan Nair.
At the early warning centre, seismic and sea-level data are continuously monitored. Operational since October 15, 2007, the system detects tsunamigenic earthquakes in the Indian and global oceans within 10 minutes and disseminates advisories to national and state disaster management authorities.
Notably, Unesco’s Intergovernmental Oceanographic Commission (IOC) has recognised the Indian unit as a primary ‘Tsunami Service Provider’ for the Indian Ocean region. “Since 2012, the centre has provided tsunami advisories to 25 countries along the Indian Ocean rim,” says Balakrishnan.
He underscores that while preventing a disaster is impossible, timely warnings, preparedness, effective response, and public education can mitigate its impact. In recognition of this, the world observes Tsunami Awareness Day on November 5, to ensure no one is caught off-guard.
India’s situation is particularly concerning. “The Indian Ocean is likely to be affected by tsunamis generated by earthquakes from two primary regions: the Andaman-Nicobar-Sumatra Island Arc and the Makran Subduction Zone (a boundary between the Arabian and Eurasian tectonic plates),” Balakrishnan notes.
“These regions are monitored using a real-time network of seismic stations, tsunami buoys, and tide gauges.”
He adds that INCOIS has also been working on detecting atypical tsunamis (generated by non-seismic sources like unusual weather events).
“So far, the Indian TEWS has monitored about 730 tsunamigenic events (earthquakes with a magnitude of 6.5 on the Richter Scale and higher) worldwide,” says Balakrishnan.
“Now, we can detect any earthquake in five to six minutes and provide timely tsunami advisories. The Indian TEWS has been recognised as one of the best tsunami warning centres in the world.”
Private weather analyst K Jamshad, better known as “Weatherman Kerala” on social media, says Indian coasts, including parts of Kerala, are near the Pacific Ring of Fire, the world’s most seismically active region, which holds 90 per cent of the world’s volcanoes. The 2004 Indonesian tsunami and the 2011 Japan earthquake and tsunami occurred within this area.
In the event of a strong offshore earthquake – particularly in Indonesia, Malaysia, the Bay of Bengal, Sri Lanka, Kanyakumari, or the southwest Arabian Sea – Kerala should anticipate a tsunami, he cautions.
“India’s sea-level monitoring stations are near the Andaman in the Bay of Bengal, Indonesia, Minicoy Island, Kochi, Goa, and Gujarat. However, two near Gujarat and some in the Bay of Bengal (belonging to India and Thailand) are currently non-operational,” explains Jamshad, who heads Metbeat, a private weather agency.
“Despite this, the system still provides warnings by tracking water levels at other locations.”
In addition to the early warning system, INCOIS conducts regular workshops, training, and mock drills to spread tsunami awareness and build capacity for disaster management. To enhance community preparedness, the Central agency coordinates the ‘Tsunami Ready’ programme, led by Unesco.
Alappad is one of nine villages in Kerala participating in the programme this year.
On World Tsunami Awareness Day 2024, Ullas is leading a mock drill in Alappad panchayat. “From swift evacuation to rescuing people caught in rising water, the mock drill helps us prepare,” he says, after concluding the drill.
He and the team from INCOIS, along with the Kerala State Disaster Management Authority (KSDMA) and local agencies, will now analyse each part of the drill to perfect their preparedness.
“There are more than 200 coastal villages in the state. For now, we have selected nine villages from as many coastal districts,” says KSDMA secretary Sekhar Lukose Kuriakose. “By 2025, as the first phase concludes, these villages will be declared tsunami-ready.”