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December 26 Tsunami

Updated on October 15, 2013

Quick Facts

  • The earthquake that caused the Boxing Day Tsunami was so large that it actually shifted the planet, knocked it off balance and shortened that day by three millionths of a second.
  • In some places waves were as high as 15 meters (50 feet).
  • Up to a third of the number of people who died were children.
  • Many people who survived the initial waves were carried out to sea when the ocean retreated.
  • More than 280,000 people lost their lives

Boxing Day Tsunami 2004

December 26, 2004 saw the occurrence of one of the most destructive tsunamis in modern times. Triggered by a powerful earthquake in the Indian Ocean, it took seven hours to destroy villages and towns from Indonesia to Africa and resulted in a catastrophic death toll of more than 280,000 people. A huge number of nations suffered casualties, and the world united in their grief along with their humanitarian relief aid for the areas worst affected.

What is a Tsunami?

The term tsunami comes from the Japanese and loosely translates to ‘harbour wave’. The term was coined by Japanese fishermen who returned to their home port to find the harbour devastated by waves. A tsunami is a series of fast moving waves which are generated when a body of water is suddenly displaced. Typical causes of tsunamis include earthquakes, landslides, volcanic eruptions and even the impact of meteorites. Out in open sea they are barely noticeable, appearing as little more than a ripple in the water; yet the speed of them can be up to 1000 kilometres per hour in open water. Once they approach land the shallow water acts as a brake and the front of the wave slows, while the back of the wave continues at the previous speed it reached. Once the back of the wave hits the front of the wave, a giant wall of water is formed.

Not all tsunamis form the wall of water they are so often associated with; some are more likened to a rapidly rising tide. The distance between wave crests can be as greater than 100 kilometres apart. The force of a tsunami is one of the main issues with the level of destruction it has the potential to cause. Normal waves are typically wind driven and it is only the top of the body of water which is affected by this. In a tsunami, the displacement of water means that the entire body of water from surface to seabed is moving, with little to stop it. Things such as reefs, undersea formations and river entrances may dissipate a tsunami’s energy but the fact remains that the displaced water must end up somewhere.

One of the warning signs of a tsunami approaching, and often the only sign when monitoring was not available, is a receding ocean. Prior to the arrival of a tsunami to land, the tide suddenly recedes, pulling back as far as the horizon and leaving the seabed exposed. It is estimated that when this occurs people in the area will have five minutes or less to attempt to reach higher ground before the tsunami hits.

Source

What caused the tsunami?

The Earth’s crust is divided into a number of tectonic plates; massive plates of rock which ‘float’ over the earth’s magma and mantle layers. All up, there are 12 individual plates which move constantly due to the heat and forces within the Earth. In a process known as subduction, a continental plate will slip under a denser oceanic plate. The India Plate is part of a larger mass (the Indo-Australian Plate) and lies underneath the Indian Ocean. The Burma Plate is also part of a larger mass (the Eurasian Plate). The boundary for these two plates is found off the coast of Sumatra in a palce known as the Sunda Trench. At this trench, the India Plate has slowly been slipping underneath the Burma Plate and the region is known for its high level of volcanic activity and earthquakes due to the force and pressure produced by this particular subduction. It was this which caused the Boxing Day Tsunami.

On December 26, 2004 at 00.58.53GMT (07.58.53 local time) 1200 kilometers of the Sunda Trench faultline slipped approximately 15 meters along the India Plate-Burma Plate subduction zone. This type of massive rupture is known as a ‘megathrust’. The resulting earthquake from this particular megathrust measured 9.0 on the Richter scale and lasted more than four minutes. It was the most violent earthquake ever recorded.

The energy released from this quake was equivalent to 10,000 Hiroshima atomic bombs. The result of this massive release of energy, was that the energy was transferred to a water column that sits above the ocean floor. It is estimated that this, combined with the movement of the plates, raised the seabed by several meters and displaced millions of litres of water in the process. As the raised area collapsed, water was forced away from it and the tsunami waves were formed.

Sumatra plate animation

Chain of Events

Within 15 minutes of the earthquake, Banda Aceh in Sumatra was struck by the first of the tsunamis generated from the water displacement. 15 minutes after Aceh was hit, Andaman, the Nicobar islands and Malaysia were hit. Thailand closely followed, then 2 hours after the earthquake Sri Lanka, and the south-east coast of India were hit, followed by the Maldives. Seven hours after the quake and 4500 kilometres from the epicentre, the east coast of Africa was hit.

In 1949 after the 1946 Aleutian Island tsunami, countries in the Pacific Ocean banded together to develop and deploy a tsunami warning system. The Pacific Tsunami Warning Centre in Honolulu analyse data from 120 seismometers located around the pacific basin. Measuring ground motion and movement, the seismometers signal the centre and geologists are able to determine if an earthquake has occurred. Coastal tide gauges and deep ocean pressure sensor data is also relayed to the centre which allows them to determine whether any tsunamis are approaching. The Indian Ocean had no warning system in place.

Source

Indonesia

The 225,000 inhabitants of Banda Aceh were the first to know something was wrong. Being the nearest big city to the epicentre, Banda Aceh felt the tremors of the earthquake. 15 minutes later the tsunami hit. Survivors described a rumbling sound, much like the sound the earthquake made but with no tremors, followed by walls of water which were twice the height of the coconut trees that lined the coast. The waves moved inland and the region was devastated. 60 percent of Banda Aceh was completely destroyed by the tsunami and the death toll was high. This posed a massive problem for survivors and humanitarian relief workers once they were able to reach the affected region. The fear of dysentery and cholera spreading to the surviving population was a major concern and thousands of people were buried in mass graves without waiting for identification in an effort to prevent disease spreading to survivors.

The town of Leupeung was obliterated, its population which numbered 10,000 before the tsunami hit was reduced to the few hundred people who managed to escape to higher land in time. The Lhoong sub-district was also hit hard, the 28 villages it boasted before the tsunami were reduced to a mere 4 surviving villages. In the fishing village Lhokseumawe only two houses remained standing, the rest were completely destroyed.

By the end of January 2005, the Indonesian death toll was over 225,000 people. In addition to the number of deaths, an estimated 800,000 people were left homeless in the provinces hit by the waves.

Source

Sri Lanka

The first people hit by the tsunami in Sri Lanka were the 1600 passengers travelling on the Queen of the Sea train on Sri Lanka’s west coast. One giant wave, at least six meters or twenty feet high, swept the train off the track. Half an hour later the second wave hit while survivors scrambled to reach higher ground. Over 1500 people died in that one incident. The east coast of Sri Lanka was the worst hit. Batticaloa, Trincomalee, the Amparai district were devastated and almost ten percent of Sri Lanka’s population was left homeless.

Over 30,000 deaths were confirmed, making Sri Lanka second to only Indonesia in the loss of lives from the tsunamis.

India

Around 300 people were on Manginapudi beach to celebrate the eve of the full moon day in the Hindu holy month of Margasirsa when the tsunami hit. Further up the coast at Vailankanni, around 500 Hindu and Christian pilgrams died when the waves swept onto the beach.

Coastal communities in Tamil, Nadu, Pondicherr, Andhra Pradesh and Kerala suffered over 10,000 deaths when the second wave hit at around 9:30am – half an hour after the first wave hit the coast.

It was the first time India had experienced a tsunami and up until 4:30pm the next day, they were still feeling the aftershocks from the initial earthquake.

Out of 15,000 fishing vessels which lined the Tamil Nadu coast, there were only three surviving. This region also suffered the highest death toll with around 8000 lives lost out of the total 10,000 Indian death toll.

Learn more about tsunamis

Thailand

The western coast of Southern Thailand was the first hit by the tsunamis, which came in a rapid succession of waves and killed over 5000 people, half of them tourists. Survivors say there were three waves, each deeper than the last, and the third being the most powerful of them all.

Phuket suffered the least number of lives lost, largely due to the modern infrastructure which allowed people to quickly escape the waves. Khao Lak, 80 kilometres north of Phuket and built only a few meters above sea level, was not so lucky and over 4000 people were killed when the waves devastated the resort. On one single, short stretch of beach at least 3000 people died.

Africa, Andaman and Nicobar, Seychelles, Maldives

4500 kilometres from the epicentre of the earthquake, and seven hours after the first tsunamis hit Banda Aceh, Somalia on the east coast of Africa was hit. At least 150 people died as four waves rushed in and out. Hafun was the worst affected and in total 30,000 people lost their homes or livelihood from these waves.

Andaman and Nicobar Islands are an archipelago consisting of 572 islands, 36 of them inhabited. Car Nicobar was hit by a 15 metre (50 foot) wave. In just a few minutes, half the 10,000 strong population of Car Nicobar was gone and 80 percent of the island was destroyed.

The Maldives consists of a cluster of 1192 tiny coral islands, with 199 of them being inhabited. Twenty of the inhabited islands were completely destroyed when the waves hit.

The bridge which links the Seychelles international airport to Victoria, the capital city of the island, was snapped in half by the waves.

Humanitarian relief and the rebuilding operation

The world mourned with the regions hit, and few nations were spared loss of life in the affected areas. The first issue humanitarian relief workers encountered in the wake of the Boxing Day Tsunamis was that unless billions of dollars of aid was raised and appropriately distributed, thousands of survivors would die from malnutrition and disease in the weeks after the disaster. Hundreds of thousands of people donated money, fundraising events were held, celebrities pledged or donated money and aid agencies began to bring in food, safe drinking water, clothing and temporary shelter for survivors.

The rebuilding operation was a long one, and some provinces never recovered from the devastation the tsunamis brought when they swept inland that Boxing Day morning.

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      Howard Schneider 3 years ago from Parsippany, New Jersey

      Very thorough and informative Hub, Rebecca. This was a devastating event for so many. I hope the world has learned a lot from it.

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      Fred 3 years ago

      New. Madrid. Earthquake. December 26th. 2013. 9.6. Earthquake Memphis. St. Louis. Chicago will. Have. A. Tsunami

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      Sammy 3 years ago

      I. Was. In. The. 2004. Tsunami. And. My. Mom. And. Dad. And. My. Brothers. And. Sisters. All. 10 Of. Them. Died. In. The. 2004. Tsunami. When I. Was. 11. Years. Old.

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