2004 Indian Ocean earthquake and tsunami

For a partial list of charitable organizations accepting donations to assist the victims, see Donations for victims of the 2004 Indian Ocean earthquake.

Animation of Indonesia tsunami (Credit: NOAA)

The 2004 Indian Ocean Earthquake was an undersea megathrust earthquake of moment magnitude 9.0 that struck the Indian Ocean off the western coast of northern Sumatra, Indonesia on December 26, 2004 at 00:58:49 UTC (07:58:49 local time in Jakarta and Bangkok). It was the largest earthquake on Earth since the 9.2-magnitude Good Friday Earthquake which struck Alaska, USA, on March 27, 1964, and the fourth largest since 1900, tying with a 1952 earthquake produced by a volcano in Kamchatka which erupted again on December 28. Tens of thousands have been killed by tsunamis, which were as high as 15 m and struck between 15 minutes and 10 hours after the quake, causing one of the most cataclysmic natural disasters in modern history.

The multiple tsunamis struck and ravaged coastal regions all over the Indian Ocean, devastating regions including the Indonesian province of Aceh, the coast of Sri Lanka, coastal areas of the Indian state of Tamil Nadu, the resort island of Phuket, Thailand, and even as far away as Somalia and several other countries in Africa, 4,500 km (2,800 mi) or more west of the epicenter.

The plight of the affected people and countries has prompted a widespread humanitarian response to the 2004 Indian Ocean earthquake.

Quake characteristics

The quake was initially reported as 6.8 on the Richter scale. On the moment magnitude scale, which is more accurate for quakes of this size, the earthquake's magnitude was first reported as 8.1 by the United States Geological Survey, but after further analysis they increased this first to 8.5 and 8.9 and finally 9.0.

For comparison, the largest recorded earthquake was the Great Chilean Earthquake of 1960, having a magnitude of 9.5. The only other larger quakes worldwide since 1900 were the 1964 Good Friday Earthquake (9.2) and a March 9 1957 quake ([1]) in the Andreanof Islands (9.1), both in Alaska, USA. The only other recorded 9.0 magnitude earthquake, in 1952 off the southeast coast of Kamchatka, U.S.S.R., spawned tsunamis that caused extensive damage in Kamchatka, the Kuril Islands and the Hawaiian Islands (see Top 10 earthquakes).

The hypocenter was at 3.298°N, 95.779°E, some 160 km (100 mi) west of Sumatra, at a depth of 30 km (18.6 mi) below mean sea level, within the "Ring of Fire" zone of frequent earthquakes. The quake itself (apart from the tsunamis) was felt as far away as Bangladesh, India, Malaysia, Myanmar, Singapore, Thailand and the Maldives.

The earthquake was unusually large in geographical extent. An estimated 1,200 km (740 mi) of faultline slipped 15 m (50 ft) along the subduction zone where the India Plate dives under the Burma Plate. The seabed is estimated to have risen 10m vertically, creating a shock wave in the Indian Ocean that traveled at up to 800 km/h (500 mi/h), forming tsunamis when they reached land.

The India Plate is part of the great Indo-Australian Plate, which underlies the Indian Ocean and Bay of Bengal, and is drifting northeast at an average of 5 cm/yr (2 in/yr) (or 15 m (50 ft) per 300 years), relative to the Burma Plate. The Burma Plate carries the Nicobar and Andaman Islands and northern Sumatra, and is pushed by the Sunda Plate to its east. Both the Burma and Sunda Plates are considered portions of the great Eurasian Plate. The tectonic activity that results as these plates scrape against each other led to the creation of the Sunda Arc.

Numerous aftershocks of magnitude between 5.7 and 6.3 were reported off the Andaman Islands in the following hours and days. Aftershocks off the Nicobar Islands were also reported, including ones of magnitude 7.1 ([2]), and 6.6 ([3]). Other aftershocks between magnitude 5.0 and 6.3 occurred near the location of the original quake. See also: USGS current earthquake information.

The earthquake came just three days after a magnitude 8.1 earthquake in a completely uninhabited region west of New Zealand's sub-Antarctic Auckland Islands, and north of Australia's Macquarie Island [4]. This would normally be unusual, since earthquakes of magnitude 8 or more typically occur an average of once per year. Seismologists have speculated about a possible connection between these two earthquakes, saying that the former one might have been a catalyst to the Indian Ocean earthquake, as the two quakes happened on opposite sides of the Indo-Australian tectonic plate ([5]). The possibility of a seismic chain reaction across neighboring plates has also been considered, after a series of earthquakes peaking at 5.0 also struck China's Yunnan province on December 26, killing one person and injuring twenty-three. Coincidentally, the earthquake struck almost exactly one year (within an hour) after a magnitude 6.6 earthquake killed an estimated 30,000 people in the city of Bam in Iran ([6]).

The total energy released by a magnitude 9.0 earthquake exceeds the total amount of energy consumed in the United States in one month, or the energy released by the wind of a hurricane like Hurricane Isabel over a period of 70 days ([7]). Using the mass-energy equivalence formula $E=mc^{2}$ , this amount of energy is equivalent to a mass of about 100 kg (220 lb) (much more than is actually converted to energy in a nuclear explosion), or enough to boil 5000 litres (1,300 US gallons) of water for every person on Earth.

The moment of inertia of Earth is believed to have decreased a bit due to the earthquake. Because angular momentum is conserved, this would result in an increase of the angular velocity of Earth's rotation. In other words, the earthquake may have shortened the length of a day by as much as 3 µs. However, due to tidal effects of the Moon, the Earth's rotation slows by 15 µs per year. So any rotational speedup due to the earthquake would have no long-lasting effect.

Based on one seismic model, some of the smaller islands southwest of Sumatra have moved southwest up to 20 m (66 ft). The northern tip of Sumatra, which is on the Burma Plate (the southern regions are on the Sunda Plate), may also have moved southwest up to 36 m (118 ft). Other models suggest that most of the movement would have been vertical rather than lateral. The massive release of energy and shift in mass may have also caused the earth to minutely "wobble" on its axis ([8]). Further study is needed to determine the extent and nature of actual geophysical movement.

Damage and casualties

The earthquake triggered massive tsunamis which struck the coasts of the Indian Ocean (Pacific Ocean coasts saw only minor sea level fluctuations). The death toll from the earthquake, the tsunamis and the resultant floods was reported to be more than 73,000, with tens of thousands of people reported missing, and over a million left homeless. The head of the European Union's humanitarian relief operation, Guido Bertolaso, has stated, "I fear that in the end it will be more than one-hundred thousand (100,000) deaths" ([9]). Governments and NGOs fear the final death toll may double as a result of water-borne diseases such as cholera and dysentery, and other diseases such as malaria. Relief agencies report that one-third of the dead appear to be children. This is a result of the high proportion of children in the populations of many of the affected regions and the fact that children were the least able to resist being dragged by the surging waters.

Tsunamis usually occur along the Pacific Ocean coasts of the "Ring of Fire", where populations and government authorities are better prepared and early-warning systems are in place. Several lethal earthquake-caused tsunamis struck the Pacific Ocean side and near the center of the Indonesian archapeligo in recent years: Flores (December 12, 1992), Java (June 3, 1994), Sulawesi (May 3, 2000). The last tsunami near Sumatra, on the Indian Ocean side and western end of Indonesia, was caused by the eruption of Krakatoa in 1883. So the death toll of the 2004 Indian Ocean earthquake may be particularly high since this is the first Indian Ocean tsunami to strike land in 100 years, leaving the affected countries unprepared and the people unable to recognise the telltale signs of an approaching tsunami.

In addition to the large number of local residents, some tourists during the busy Christmas holiday travel season were among the casualties.

States of emergency were declared in Sri Lanka, Indonesia and Maldives. The United Nations has declared that the current relief operation would be the costliest one ever.

For purposes of establishing timelines of local events, the time zones of affected areas are: UTC+3: (Kenya, Somalia); UTC+4: (Mauritius, Réunion, Seychelles); UTC+5: (Maldives); UTC+5:30: (India); UTC+6: (Bangladesh, Sri Lanka); UTC+6:30: (Cocos Islands, Myanmar); UTC+7: (Indonesia (western), Thailand); UTC+8: (Malaysia, Singapore). Since the quake occurred at 00:58:49 UTC, add the above offsets to find the local time of the quake. A list of times can be found at [10](a USGS site).

Casualty summary

Country	Deaths		Injured	Missing	Displaced
Country	Confirmed	Estimated	Injured	Missing	Displaced
Indonesia	45,268 ([11])	Up to 80,000	—	Thousands	—
Sri Lanka	22,493 ([12])	30,000+	4,000+	4,028	1.5 million
India	12,419 ([13])	15,000+	—	30,000+	Hundreds of thousands
Thailand	1,830 ([14])	2,000+	8,953	4,086	29,000+
Somalia	110	Hundreds	—	—	—
Myanmar (Burma)	90	100+	1500+	—	200+
Malaysia	65	—	183	26	5,000
Maldives	55	—	—	76	—
Tanzania	10	—	—	—	—
South Africa	4	—	—	—	—
Seychelles	3	—	—	7	—
Bangladesh	2	—	—	—	—
Kenya	2	—	—	—	—
Madagascar	0	—	—	—	1,200
Total	82,351	Up to 125,000	—	40,000+	1.5-2 million

Note: All figures are approximate and subject to constant change

India, Indonesia, and Sri Lanka have suffered the vast majority of casualties from the natural disaster. A description of the countries most affected by the earthquake and resulting tsunamis is below. In order to make the article easier to read, the description of nations whose casualty totals cannot be counted in the dozens, as well as the account of nations that have lost citizens who were traveling abroad are listed as other countries affected by the 2004 Indian Ocean earthquake.

India

The Andaman and Nicobar Islands, just north of the earthquake hypocenter, have had the most casualties in India. The tsunami reached a height of 15 m in the southern Nicobar Islands. It is estimated that 7,000 have died on the islands, and a similar number missing. One fifth of the population of the Nicobar Islands is said to be dead, injured or missing ([15]). Chowra Island in the Nicobars has lost 2/3 of its population of 1,500. Communications have been lost with the Nan Kauri group of islands, some of which have been completely submerged, with the total number of the population out of contact exceeding 18,000. The Indian Air Force base in Car Nicobar, near the hypocenter, is reported to have been severely damaged ([16]).

On mainland India, the entire eastern coast was affected, killing more than 5,000 and rendering thousands injured and/or homeless [17]. The death toll in Tamil Nadu, which was most affected, was above 3,200. Along the eastern coast, 487 were killed in Pondichery and 89 in Andhra Pradesh. Kerala, located on the southern part of the western coast of India, was also affected with 174 deaths and thousands rendered homeless. Hundreds were feared missing (1,200 in Andhra Pradesh alone). Most of the people killed were fisherfolk who lived along the coast. Many fishermen both at home and at sea were missing.

In Tamil Nadu where the official toll was 3,200, mostly women and children, over 1,700 were killed in the Nagapattinam district alone, over 400 in the Cuddalore district, over 525 in the Kanyakumari district and over 200 in Chennai (formerly Madras) city. It was reported that survey and rescue helicopters could not even land in Nagapattinam and Cuddalore districts due to floods and rains.

Those killed in Kanyakumari include pilgrims taking a holy dip in the sea. Of about 700 people trapped at the Vivekananda Memorial on an island off Kanyakumari, 650 were rescued while the search is on for others. In Chennai along the Marina Beach, people taking part in various sports activities (including children), and those who were having a morning walk along the beach, were washed away. It being a Sunday, there were more people than usual on the beach. Some unconfirmed reports claim that at least 5,000 fishermen and their families may be missing just from the Marina Beach area.

A large number of pilgrims celebrating Christmas at the Velankanni church were affected. Eyewitness reports suggest that at least 1,000 people were on the beach on that morning.

Water also rushed into the nuclear reactor complex at Kalpakkam, which was then shut off. No damage or radiation leak was reported ([18]).

The Indian Army, Navy and Coast Guard were pressed into service for undertaking rescue operations and to air-drop food to the tsunami victims. The chief ministers of Tamil Nadu and Andhra Pradesh announced ex gratia relief for those affected by the tsunamis.

Indonesia

Indonesia's Ministry of Health confirmed 45,268 dead. Nine thousand are reported dead in the provincial capital of Banda Aceh and nearby towns, where dozens of buildings were destroyed in the initial earthquake. This preliminary figure does not include much of badly damaged western coast of Sumatra. One government official estimated another 10,000 dead in the single town of Meulaboh, 160 km (100 mi) in the northern province of Aceh (officialy named Nanggroe Aceh Darussalam), while another 'government official' gives to a UN official an estimate of 1/3 of the town's population (about 40,000). Northern Sumatra was unusual in the regional disaster in that it took damage from the earthquake itself as well as the tsunami. Hundreds of thousands of people have been rendered homeless ([19]).

The unmanageably high number of corpses strewn all over the cities and countrysides, limited resources and time for identifying bodies, and the very real threat of cholera, dypthery and other diseases have prompted emergency workers to create makeshift mass graves. One of the most urgently required medical supplies now are body bags ([20]).

Government officials are very concerned over the lack of reports from the many small islands dotting the western coast of Sumatra. These islands are among the poorest areas in Indonesia, among them the islands Simeulue and Nias. On Nias island alone official acounts gave the number 122 (source: Media Indonesia Online via the Ministry of Health), while various unconfirmed sources (mostly from phone calls by relatives living in Jakarta) report death tolls of over 600, while others say the number more likely to go well over 1000. Confirmation and communications to the islands are further hampered by damage to telecommunication infrastructures, where phone lines are broken and radio networks have been said to be down due to bad weather (source: KCM, updates from The Jakarta Post).

Three small islets off the coast of Nias island in the Sirombu district has been speculated to be completely submerged, although reports have surfaced that they are both still relatively intact ([21]). High waves still prevent locals from attempting to reach the islands (niasisland.com).

Most damage was the result of the tsunamis that struck the coastal regions of Aceh and North Sumatra provinces. Ten metre tall tsunamis passed the tip of the island to race south down the Straits of Malacca and strike along the northeast coast near the town of Bireun. The west coast of Sumatra was about 100 km (60 mi) from the epicenter and is believed to have taken heavy damage. At least five villages were completely destroyed. Overflights of the region show that thousands of homes remain underwater. Reports indicate that survivors survived for days eating nothing but coconuts and looting has been reported in stricken Acehnese towns.

An accurate picture of the damage is made difficult due to the insurgency of the separatist Free Aceh Movement (also known as GAM or Gerakan Aceh Merdeka), which means that there were relatively few journalists, government offices, or aid workers in northern Sumatra. On Monday the government stated that on Wednesday it would lift the 18-month-old ban prohibiting foreign journalists and aid workers from traveling to Aceh. Also on Monday, a spokesperson for the Free Aceh Movement declared a ceasefire so humanitarian aid could reach survivors, and so as not to complicate the already devastating situation. The GAM also stated that 50,000 people were displaced in Aceh.

Fifteen thousand troops, who were in the region to fight the insurgency, have been dispatched to render assistance and to search for survivors. 3 days of national mourning have been declared.

The central government has declared the local Acehnese government as totally crippled and have declared that all administrative controll will be handled directly from Jakarta.

Malaysia

Malaysia escaped the kind of damages that struck beaches thousands of miles further away. This is attributed to the the position of the epicentre which was on the west side of the island of Sumatra, which shielded Malaysia. Credit should also go to the local tv stations for broadcasting tsunami alerts within the hour of the quake. The limited number of casualties were from people being swept away from beaches as the tsunami hit Malaysia which resulted in the deaths of 63 people as of noon local time: 49 (2 unindentified victims) in Penang, 10 in Kedah, 3 in Perak and one in Selangor. The deaths at Penang were reported to include many picnickers and children who were playing on the beach. No deaths are reported among foreign tourists. At noon on 28th Dec the death toll is reported to have risen to 63 with 29 people missing, 275 injured and 4000 homeless. Houses in villages along coastal areas were badly damaged in Penang, Kuala Muda in Kedah and numerous fishing boats were destroyed on Langkawi island. The waves sent parked motorcycles crashing and cars washed with mud at stretches along Gurney Drive. The biggest lost from a single family was when 5 of 7 children of Zulkifli Mohamad Noor was killed when the tsunami struck at Pasir Panjang beach. The biggest risk is post disaster risk like food and water-borne diseases e.g. cholera and typhoid and dengue from stagnating water. The tremor of the quake was felt by office workers in the PETRONAS Twin Towers.

Malaysian Prime Minister Dato' Seri Abdullah Ahmad Badawi cut short his holiday in Spain and returned to Malaysia. The Malaysian government announced that MYR 1,000 (USD 263.16) would be paid to the families of victims while MYR 200 (USD 52.63) would be paid to those who had sustained injuries from the tsunami. Residents who moved out of their homes immediately would also be paid MYR 200 as compensation.

Sinkholes have now been reported in Kampar and Ipoh for 3 days running since the quake. The matter is still under investigation and could well be a precursor to further quake related phenomena.

Maldives

In the Maldives, 68 were killed and 76 reported missing, with both figures expected to rise as communication links are restored. Two-thirds of the capital city Malé was flooded during the early hours of the day. Outlying low-level atolls were badly affected and some low lying islands were completely submerged, including some of the major resorts, during the high tide.

The government has declared a state of national disaster ([22]) and a special task force has been set up to provide aid and supplies. Rescue efforts have been hampered by loss of communication capability, as well as the lack of a prior rescue or relief plan for a disaster of this nature.

Somalia

Villages and coastal communities in Somalia, as far as 4,500 km (2,800 mi) from the epicentre of the earthquake, were swept away and destroyed by the huge waves. Prime Minister Ali Mohammed Gedi of the government-in-exile has stated that over 100 people are dead. Rising waters engulfed the town mosque of Brava and the villages of Beyla, Garacad, Muduy and Nugaal, all in Puntland, were reported destroyed.

According to Ali Abdi Awari, Minister of Rural Development, the final toll is believed to be much higher, as the number of fishermen caught on the sea has not been established by the local authorities. Much of the 621-mile coast is controlled by various clan-based militias, making obtaining accurate information difficult. The United Nations is assisting 2,000 people in Hafun, a town 715 miles northeast of Mogadishu, who were made homeless by the tsunamis.

Myanmar (Burma)

Ninety people have been confirmed killed by tsunamis in Myanmar, also known as Burma. Most deaths were in the Irrawaddy Delta and several villages and a bridge destroyed. The ruling military dictatorship rarely release details about any disaster, so exact numbers of casualties and homeless are difficult to obtain. International humanitarian organisations in Rangoon report 56 deaths, but expect the final toll to be significantly higher.

Sri Lanka

Sri Lankan authorities report nearly 22,000 confirmed deaths, mostly children and the elderly. The south and east coasts were worst hit. The army states that over 10,000 bodies have been recovered in government-held areas.

The rebel Tamil Tigers who control much of the north and east have stated that the number of dead in rebel-held areas could rise to 6,000. War-damaged infrastucture means it is likely to mean that it will take longer before accurate figures are available for these areas.

File:Srilanka kalutara thumb1.jpg

Satellite photo of southwestern coast of Sri Lanka shortly after the tsunami struck. (DigitalGlobe)

1200 dead were counted at Batticaloa in the east and at Trincomalee in the northeast, where the tsunami reached more than 2 km (1.25 mi) inland, 800 were reported dead. The naval base at Trincomalee is reported to be submerged. About 1000 more dead were counted in Mullaitivu and Vadamaradchi East ([23]). A train, the "Sea Queen", moving between Colombo and Galle, with 1,600 passengers was struck by a tsunami, killing all but 300 on board.

More than one million people have been displaced from their homes. Apart from homes, many hotels were also reported to have been damaged. Hotels along the south coast were full of both foreign tourists and Sri Lankans making use of the long Christmas weekend. Twenty thousand soldiers were deployed in government-controlled areas to assist in relief operations and maintain law and order after sporadic looting. Curfews had been imposed in some areas to curb looting. Chinese light antipersonnel mines of type T-72A, left after the two-decade civil war, are feared to have been washed up and spread by the surge of water. The Norwegian Peoples' Aid organization is currently assembling a team of mine sweepers to assess the situation.

The main highway to the south runs along the coast and was closed in the aftermath of the tsunami, delaying relief supplies. A huge effort to deliver supplies has been made by large numbers of private individuals filling their own vans and pickup trucks with food, clothing and bottled water and driving to affected areas.

Author Sir Arthur C. Clarke, who lives in Sri Lanka, has issued a statement saying that Sri Lanka "lacks the resources and capacity to cope with the aftermath". Clarke reported that not all of his staff have been accounted for. Clarke's diving school has been destroyed.

Thailand

The Thai government reports that over 2,000 are feared killed, with 1,657 confirmed deaths and 8,953 injuries [24]. The popular tourist resort of Phuket was badly hit. The smaller but increasingly popular resort area of Khao Lak some 80 km north of Phuket was hit far worse and there are said to be around 700 corpses on the beach in Khao Lak, while the total amount of dead in Khao Lak may exceed 2,000. The severity of the situation in Khao Lak is probably explained by the fact, that unlike the high-rising city of Phuket, the village of Khao Lak only had low built bungalows instead of high-rise concrete hotels. Khao Lak also has an extensive area of flatland only a few metres above the sea level, on which most bungalows were situated.

Thailand deputy interior minister Sutham Sangprathum reports over 700 tourists among Thailand's casualties. The bodies of 44 foreign tourists are reported to have been recovered at Phuket. Hundreds of holiday bungalows on the Phi Phi Islands were washed out to sea. Lorry drivers were quick to offer assistance, driving victims to higher ground and away from the surging waters. Local reports say many scuba divers were found dead, with their bodies torn apart by the tsunami. Among the dead was Bhumi Jensen, a grandson of King Rama IX, whose body was found at Phang Nga on Monday afternoon.

Other countries

Main article: Other countries affected by the 2004 Indian Ocean earthquake

A number of other countries were also affected either directly or indirectly by the earthquake. Countries such as Tanzania lost citizens as the tsunami struck its shores and other countries suffered significant property damage. Meanwhile, nations like Oman and Australia reported only non-deadly ocean swells. Citizens from countries from around the world have been killed, or remain missing, in the aftermath of the natural disaster. Many foreigners were visiting the famed beaches of Thailand and Sri Lanka during the winter vacation.

Damage in historical and global context

File:2004 indian ocean earthquake tectonic.jpg

Regional map showing physiographic features, tectonic plate movements, and locations of volcanoes, earthquakes, and impact craters

Although the earthquake was the fourth most powerful recorded since 1899, the likely death toll is lower than would have been the case if it had struck at a densely populated area. The deadliest earthquakes recorded in recent times were the Tangshan, China, earthquake of 1976, in which 240,000 were killed, and the Tokyo earthquake of 1923 (140,000). The deadliest earthquake in history occurred in 1556 in Shaanxi, China, with a reported death toll of 830,000, though figures from this time period may not be reliable ([25]).

The nations of the Indian Ocean do not yet participate in a regional tsunami early warning system like that in the Pacific Ocean, though neither do the nations of the Atlantic Ocean. In the Pacific, a system of sensors is linked to monitoring stations so that local media can warn the populace to seek higher ground well before a tsunami arrives. The system dates back to 1965 and was a reaction to the tsunamis resulting from the 9.2 seaquake of 1964, which is the last quake of 9.0 or larger magnitude. Thailand is a member of the Pacific tsunami warning system, but all of its ocean buoys, upon which wave sensors are mounted, are on the east coast of the country. A single wave station south of the epicenter measured a two foot tall tsunami moving towards Australia. The US Geological Survey has stated that if a monitoring and warning system had been in place, the loss of life could have been reduced, especially in areas that were struck by tsunamis more than three hours after the initial tremor, such as Sri Lanka and India. Furthermore, in Pacific regions where tsunamis are better known, the receding of the sea from the coast would have warned many people of an impending ocean surge. In the Indian Ocean region, this rare sight has been reported to have induced people to visit the coast to investigate. Also, the intensity of the tremors in India and Sri Lanka was too low to raise an alarm.

In the aftermath of the earthquake, the Indian government has decided to install equipment to warn about impending tsunamis, and to join a group of countries that would share information on tsunamis. The Malaysian government has also proposed to create a tsunami warning system, in cooperation with other countries in the region ([26]).

Post-tsunami humanitarian situation

Main article: Humanitarian response to the 2004 Indian Ocean earthquake

A great deal of humanitarian aid is needed due to widespread damage to infrastructure, food and water shortages, and economic damage to the fishing and tourism industries. Epidemics are of special concern, as they are highly likely due to the high population density and tropical climate of the affected areas. The United Nations has stated that the largest relief operation in history is underway. The overwhelming concern of humanitarian and government agencies is to quickly identify and bury the dead before they become a health issue, and also contain the spread of diseases such as cholera, diphtheria, dysentery and typhoid.