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On This Day in 2004: Powerful Indian Ocean Tsunami

December 26, 2022
By WeatherBug's Richard Romkee
On this day in 2004, the Boxing Day Tsunami wrought intense devastation to coastlines across the Indian Ocean.

Like most tsunamis, the Boxing Day Tsunami began with a massive earthquake. The earthquake in question registered a 9.2 on the Richter scale, and was centered just off the southwestern coast of Sumatra, Indonesia. The earthquake released an incredible amount of energy (110 petajoules, or around the amount of energy Earth receives from the Sun every second), and also thrusted a large portion of the Indian Ocean seafloor upwards by up to 40 meters.

This upward thrust of the seafloor displaced around 7.2 cubic miles of water, which is roughly the volume of Lake Michigan. All of this water had to go somewhere, and it spread out from the epicenter as a shallow but speedy wave. While satellite measurements indicated that the wave was only around 2 feet tall over the open ocean, it was moving across the Indian Ocean at anywhere from 300 to 600 mph.

 When this wall of water reached land, the results were cataclysmic. Twenty minutes after the earthquake, Aceh Province, Indonesia, was decimated by waves estimated to have reached 80 to 100 feet tall near the immediate coast. Tall buildings were completely inundated, and the lack of an early alert system left the residents of Banda Aceh, the province’s largest city, severely underprepared. Indonesia was the hardest hit country by far: anywhere from 130,000 to 200,000 residents died, over half a million residents were displaced and $6 billion worth of damage was tallied overall.

Sri Lanka was next in line for the tsunami, and the island was hit not once but several times by the massive wave as it rebounded around the Bay of Bengal. The eastern side of the island was hit hardest by waves which reached as high as 41 feet in southeastern Sri Lanka. It was here in Sri Lanka that the tsunami overtook a packed passenger train on the western side of the island near the community of Peraliya. Waves up to 10 feet taller than the train itself caused a severe derailment and ultimately led to the deaths of anywhere from 1,700 to 2,000 people. Over 90,000 buildings in Sri Lanka were destroyed with a total of 35,000 fatalities reported across the island nation.

Thailand was slammed by the tsunami about 2 hours after the earthquake, and a 20 foot wall of water smashed the western side of the island. The death toll reached 8,000 in Thailand, with 5,000 deaths in the city of Khao Lak alone. A total of 47 villages were completely destroyed by the giant wave, with hundreds of thousands of residents losing everything.

India was hit next, with the wave hitting the east coast about 2 hours after the triggering earthquake. The tsunami reached heights of 10 to 20 feet, with water reaching up to a mile inland. Some unfortunate areas received 3 or more tsunami waves thanks to reverberation around the Bay of Bengal, similar to their neighbors in Thailand and Indonesia. Sea walls protected a select few cities, but most were hit hard with 12,000 residents killed and up to 647,000 displaced.

As the mammoth wave rippled outwards, several other Asian nations experienced significant impacts. The Maldives, just south of India, were hit with 4 to 10 foot waves which damaged buildings and sadly claimed up to 108 lives. Myanmar was relatively close to the epicenter, but due to geographic geometry and protection from the Myeik Archipelago waves only reached 9 feet at most. Unfortunately, the small nation suffered 90 confirmed deaths and an estimated 400 to 600 assumed deaths amongst the missing. Bangladesh suffered 2 deaths as the tsunami capsized a boat off the southern coast of the small nation.

After 7 hours of travel across the Indian Ocean, the tsunami made landfall in Somalia. As with eastern India in the Bay of Bengal, ricocheting wave energy around the Arabian sea and Gulf of Aden led to a total of four waves, the highest of which measuring 15 to 30 feet tall, crashing onto the shores of the Horn of Africa. In addition to significant damage to homes and businesses, an estimated 289 residents died as a result of the tsunami. The neighboring nation of Yemen suffered two deaths from waves up to 6 feet tall.

The rest of eastern Africa was hit by the tsunami anywhere from 8 to 12 hours after the initial earthquake which set the entire tragedy in motion. One Kenyan drowned near the coastal city of Mombasa, with 10 deaths reported in Tanzania and 9 deaths in the Seychelles. Although over 1,000 residents were displaced in Madagascar by the waves, no deaths were reported. South Africa was the last nation to suffer deaths in the tsunami, with 2 confirmed drownings and severe harbor damage as the wave rippled through.

All told, an estimated 227,000 residents of 14 nations died as a result of the tsunami. This tally also includes 2,233 tourists from 45 countries who were on Christmas vacations when disaster struck. Of these, 543 were from Sweden, 539 were from Germany and 179 from Finland. Switzerland and the United Kingdom also both suffered 100 or more deaths. Estimates place the direct economic losses from the tsunami at $10 billion, with indirect losses both being much greater and less tangible. Finally, 1.7 million people were displaced as a result of property damage caused by the wave.

As the world slowly became aware of the scale of the cataclysm in the days that followed December 26, a massive humanitarian response was launched. The World Food Program sent large amounts of food to affected areas, serving 1.3 billion meals in total. $14 billion in government aid was sent to the disaster area by 57 nations and intergovernmental agencies, with billions more donated by non-governmental agencies and individuals.

The lasting legacy of the Boxing Day Tsunami exists in the form of the Indian Ocean tsunami warning system. Similar warning systems have existed for the Pacific Ocean since 1949, but the Indian and Atlantic Oceans did not have such systems until 2005 as the need was either not understood or ignored by various world governments. This tsunami made that need obvious in the form of a worst case scenario coming to fruition, and efforts were made to bolster existing systems and establish new ones in vulnerable regions.

Source: Wikipedia

Story Image: Debris litters a street in Banda Aceh, Indonesia after the Boxing Day Tsunami. (Michael L. Bak via Wikimedia Commons)