The
2004 Indian Ocean earthquake was an
undersea megathrust earthquake that occurred at 00:58:53
UTC on December 26, 2004, with an
epicentre off the west coast of
Sumatra,
Indonesia. The quake itself is known by the
scientific community as the
Sumatra-Andaman earthquake.
[3][4] The resulting
tsunami is given various names, including the
2004 Indian Ocean tsunami,
Asian Tsunami,
Indonesian Tsunami, and
Boxing Day Tsunami.
The earthquake was caused by
subduction and triggered a series of devastating
tsunamis along the coasts of most landmasses bordering the
Indian Ocean, killing over 230,000 people in fourteen countries, and inundating coastal communities with waves up to 30
meters (100
feet) high.
[5] It was one of the
deadliest natural disasters in recorded history.
Indonesia was the hardest hit, followed by
Sri Lanka,
India, and
Thailand.
With a
magnitude of between 9.1 and 9.3, it is the
third largest earthquake ever recorded on a
seismograph. This earthquake had the longest duration of faulting ever observed, between 8.3 and 10 minutes. It caused the entire planet to vibrate as much as 1 cm (0.4 inches)
[6] and triggered other earthquakes as far away as
Alaska.
[7] Its
hypocenter was between
Simeulue and mainland Indonesia.
[8]The plight of the many
affected people and countries prompted a worldwide
humanitarian response. In all, the worldwide community donated more than $7 billion (2004
U.S. dollars) in humanitarian aid.
Earthquake characteristics
The
earthquake was initially reported as
moment magnitude 9.0. In February 2005 scientists revised the estimate of the magnitude to 9.3.
[9] Although the
Pacific Tsunami Warning Center has accepted these new numbers, the
United States Geological Survey has so far not changed its estimate of 9.1. The most recent studies in 2006 have obtained a magnitude of M
w 9.1–9.3. Dr.
Hiroo Kanamori of the
California Institute of Technology believes that M
w 9.2 is a good representative value for the size of this great earthquake.
[10]The
hypocentre of the main earthquake was approximately 160 km (100 mi), in the Indian Ocean just north of
Simeulue island, off the western coast of northern Sumatra, at a depth of 30 km (19 mi) below
mean sea level (initially reported as 10 km). The northern section of the
Sunda megathrust, which had been assumed
dormant, ruptured; the rupture having a length of 1300 km.
[8] The size of the rupture caused plate shifting of up to 20 m,
[citation needed] causing the earthquake (followed by the tsunami) to be felt simultaneously as far away as
Bangladesh,
India,
Malaysia,
Myanmar,
Thailand,
Singapore and the
Maldives.
[11] Splay faults, or secondary "pop up faults", caused long, narrow parts of the sea floor to pop up in seconds. This quickly elevated the height and increased the speed of waves, causing the complete destruction of the nearby Indonesian town of
Lhoknga.
[12]Indonesia lies between the
Pacific Ring of Fire along the north-eastern islands adjacent to and including
New Guinea and the
Alpide belt along the south and west from
Sumatra,
Java,
Bali,
Flores, and
Timor.
Great earthquakes such as the Sumatra-Andaman event, which are invariably associated with
megathrust events in
subduction zones, have
seismic moments that can account for a significant fraction of the global earthquake moment across century-scale time periods. The Sumatra-Andaman earthquake was the largest earthquake since 1964, and the second largest since the
Kamchatka earthquake of October 16, 1737.
Of all the
seismic moment released by earthquakes in the 100 years from 1906 through 2005, roughly one-eighth was due to the Sumatra-Andaman event. This quake, together with the
Good Friday Earthquake (
Alaska, 1964) and the
Great Chilean Earthquake (1960), account for almost half of the total moment. The much smaller but still catastrophic
1906 San Francisco earthquake is included in the diagram below for perspective. M
w denotes the magnitude of an earthquake on the
moment magnitude scale.
Since 1900 the only earthquakes recorded with a greater magnitude were the 1960
Great Chilean Earthquake (magnitude 9.5) and the 1964
Good Friday Earthquake in
Prince William Sound (9.2). The only other recorded earthquake of magnitude 9.0 or greater was off
Kamchatka,
Russia, on November 4, 1952 (magnitude 9.0).
[13] Each of these
megathrust earthquakes also spawned tsunamis in the Pacific Ocean, but the death toll from these was significantly lower. The worst of these caused only a few thousand deaths, primarily because of the lower
population density along the coasts near affected areas and the much greater distances to more populated coasts.
Other very large
megathrust earthquakes occurred in 1868 (
Peru,
Nazca Plate and
South American Plate); 1827 (
Colombia, Nazca Plate and South American Plate); 1812 (
Venezuela,
Caribbean Plate and South American Plate) and
1700 (western North America,
Juan de Fuca Plate and
North American Plate). All of them are believed to be greater than magnitude 9, but no accurate measurements were available at the time.
Tectonic plates
A
pie graph of the largest earthquakes from 1906 to 2005.
The
megathrust earthquake was unusually large in
geographical and
geological extent. An estimated 1,600 km (994 mi) of
fault surface slipped (or ruptured) about 15 m (50 ft) along the
subduction zone where the
India Plate slides (or subducts) under the overriding
Burma Plate. The slip did not happen instantaneously but took place in two phases over a period of several minutes:
- Seismographic and acoustic data indicate that the first phase involved a rupture about 400 km (250 mi) long and 100 km (60 mi) wide, located 30 km (19 mi) beneath the sea bed—the largest rupture ever known to have been caused by an earthquake. The rupture proceeded at a speed of about 2.8 km/s (1.7 mi/s) or 10,000 km/h (6,300 mph), beginning off the coast of Aceh and proceeding north-westerly over a period of about 100 seconds.
- A pause of about another 100 seconds took place before the rupture continued northwards towards the Andaman and Nicobar Islands. However, the northern rupture occurred more slowly than in the south, at about 2.1 km/s (1.3 mi/s) or 7,600 km/h (4,700 mph), continuing north for another five minutes to a plate boundary where the fault type changes from subduction to strike-slip (the two plates slide past one another in opposite directions). This reduced the speed of the water displacement and so reducing the size of the tsunami that hit the northern part of the Indian Ocean.[14]
The
India Plate is part of the great
Indo-Australian Plate, which underlies the
Indian Ocean and
Bay of Bengal, and is drifting north-east at an average of 6 cm/year (2 inches per year). The India Plate meets the
Burma Plate (which is considered a portion of the great
Eurasian Plate) at the
Sunda Trench. At this point the India Plate subducts beneath the Burma Plate, which carries the
Nicobar Islands, the
Andaman Islands, and northern
Sumatra. The India Plate sinks deeper and deeper beneath the Burma Plate until the increasing temperature and pressure drive
volatiles out of the subducting plate. These volatiles rise into the overlying plate causing
partial melting and the formation of
magma. The rising magma intrudes into the crust above and exits the Earth's crust through
volcanoes in the form of a
volcanic arc. The volcanic activity that results as the Indo-Australian Plate subducts the
Eurasian Plate has created the
Sunda Arc.
As well as the sideways movement between the plates, the
sea floor is estimated to have risen by several metres, displacing an estimated 30 km
3 (7 cu mi) of water and triggering devastating
tsunami waves. The waves did not originate from a
point source, as was inaccurately depicted in some illustrations of their paths of travel, but rather radiated outwards along the entire 1,600 km (994 mi) length of the rupture (acting as a
line source). This greatly increased the geographical area over which the waves were observed, reaching as far as
Mexico,
Chile, and the
Arctic. The raising of the sea floor significantly reduced the capacity of the
Indian Ocean, producing a permanent rise in the global
sea level by an estimated 0.1 mm (0.01 cm or 0.0001 m).
[15]Aftershocks and other earthquakes
Locations of initial earthquake and all aftershocks measuring greater than 4.0 from December 26, 2004 to January 10, 2005. The site of the original quake is marked by the large star in the lower right square of the grid.
Numerous
aftershocks were reported off the
Andaman Islands, the
Nicobar Islands and the region of the original epicentre in the hours and days that followed. The
largest aftershock, which originated off the coast of the Sumatran island of
Nias, registered a magnitude of 8.7,
[16] prompting debate among seismologists as to whether it should be classified as an aftershock of the December 2004 quake or as a "triggered earthquake" (which typically differs from an aftershock in that it is not located along the same fault line and may be as large or larger than the earthquake which triggered it).
[17] This earthquake was so large that it produced its own aftershocks (some registering a magnitude of as great as 6.1) and presently ranks as the 7th largest earthquake on record since 1900. Other aftershocks of up to magnitude 6.6 continued to shake the region daily for up to three or four months.
[18][19] As well as continuing aftershocks, the energy released by the original earthquake continued to make its presence felt well after the event. A week after the earthquake, its reverberations could still be measured, providing valuable scientific data about the Earth's interior.
The 2004 Indian Ocean earthquake came just three days after a magnitude 8.1 earthquake in an uninhabited region west of New Zealand's
sub-Antarctic Auckland Islands, and north of Australia's
Macquarie Island. This is unusual, since earthquakes of magnitude 8 or more occur only about once per year on average.
[20] Some seismologists have speculated about a connection between these two earthquakes, saying that the former one might have been a catalyst to the Indian Ocean earthquake, as the two earthquakes happened on opposite sides of the
Indo-Australian Plate. However, the
U.S. Geological Survey sees no evidence of a causal relationship in this incident. Coincidentally, the earthquake struck almost exactly one year (to the hour) after a 6.6 magnitude earthquake killed an estimated 30,000 people in the city of
Bam in
Iran on December 26, 2003.
[21]Some scientists confirm that the December earthquake had activated
Leuser Mountain, a volcano in Aceh province along the same range of peaks as
Mount Talang, while the
2005 Sumatran earthquake had sparked activity in
Lake Toba, an ancient crater in Sumatra.
[22] Geologists say that the eruption of
Mount Talang in April 2005 is connected to the December earthquake.
[23]Energy released
The energy released on the Earth's surface only (
ME, which is the
seismic potential for damage) by the 2004 Indian Ocean earthquake and tsunami was estimated at 1.1×10
17 joules,
[24] or 26.3 megatons of TNT. This energy is equivalent to over 1502 times that of the Hiroshima
atomic bomb, but less than that of
Tsar Bomba, the largest nuclear weapon ever detonated. However, this is but a tiny fraction of the total
work done
MW (and thus energy) by this quake, 4.0×10
22 joules (4.0×10
29 ergs),
[25] the vast majority underground. This equates to 4.0×10
22 J, over 363,000 times more than its
ME. This is a truly enormous figure, equivalent to 9,560 gigatons of
TNT equivalent (550 million times that of Hiroshima), or about 370 years of
energy use in the United States at 2005 levels of 1.08×10
20 J.
The only recorded earthquakes with a larger
MW were the
1960 Chilean and
1964 Alaskan quakes, with 2.5×10
23 joules (250 ZJ) and 7.5×10
22 joules (75 ZJ) respectively.
[26]The earthquake generated a seismic oscillation of the Earth's surface of up to 20–30 cm (8–12 in), equivalent to the effect of the
tidal forces caused by the Sun and Moon. The shock waves of the earthquake were felt across the planet; as far away as the U.S. state of
Oklahoma, where vertical movements of 3 mm (0.12 in) were recorded. By February 2005, the earthquake's effects were still detectable as a 0.02 mm complex harmonic oscillation of the Earth's surface, which gradually diminished and merged with the incessant free oscillation of the Earth more than 4 months after the earthquake.
[27]Because of its enormous energy release and shallow rupture depth, the earthquake generated remarkable seismic ground motions around the globe, particularly due to huge
Rayleigh (surface) elastic waves that exceeded 1 cm in vertical amplitude everywhere on Earth. The record section plot below displays vertical displacements of the Earth's surface recorded by seismometers from the IRIS/USGS Global Seismographic Network plotted with respect to time (since the earthquake initiation) on the horizontal axis, and vertical displacements of the Earth on the vertical axis (note the 1 cm scale bar at the bottom for scale). The seismograms are arranged vertically by distance from the epicenter in degrees. The earliest, lower amplitude, signal is that of the compressional (P) wave, which takes about 22 minutes to reach the other side of the planet (the
antipode; in this case near Ecuador). The largest amplitude signals are seismic surface waves that reach the antipode after about 100 minutes. The surface waves can be clearly seen to reinforce near the antipode (with the closest seismic stations in Ecuador), and to subsequently encircle the planet to return to the epicentral region after about 200 minutes. A major aftershock (magnitude 7.1) can be seen at the closest stations starting just after the 200 minute mark. This aftershock would be considered a major earthquake under ordinary circumstances, but is dwarfed by the mainshock.
Vertical-component ground motions recorded by the IRIS/USGS Global Seismographic Network.
The shift of mass and the massive release of energy very slightly altered the Earth's rotation. The exact amount is not yet known, but theoretical models suggest the earthquake shortened the length of a day by 2.68
microseconds, due to a decrease in the
oblateness of the Earth.
[28] It also caused the Earth to minutely "wobble" on its axis by up to 2.5 cm (1 in) in the direction of 145° east
longitude,
[29] or perhaps by up to 5 or 6 cm (2.0 to 2.4 in).
[30] However, because of tidal effects of the
Moon, the length of a day increases at an average of 15
µs per year, so any rotational change due to the earthquake will be lost quickly. Similarly, the natural
Chandler wobble of the Earth, which in some cases can be up to 15 m (50 ft), will eventually offset the minor wobble produced by the earthquake.
More spectacularly, there was 10 m (33 ft) movement laterally and 4–5 m (13–16 ft) vertically along the fault line. Early speculation was that some of the smaller islands south-west of Sumatra, which is on the
Burma Plate (the southern regions are on the
Sunda Plate), might have moved south-west by up to 36 m (118 ft), but more accurate data released more than a month after the earthquake found the movement to be about 20 cm (7.9 in).
[31] Since movement was vertical as well as lateral, some coastal areas may have been moved to below sea level. The
Andaman and Nicobar Islands appear to have shifted south-west by around 1.25 m (4.1 ft) and to have sunk by 1 m (3.28 ft).
[32]In February 2005, the
Royal Navy vessel
HMS Scott surveyed the seabed around the earthquake zone, which varies in depth between 1,000 m and 5,000 m (3,300 ft and 16,500 ft). The survey, conducted using a high-resolution, multi-beam
sonar system, revealed that the earthquake had made a huge impact on the topography of the seabed. 1,500-meter (5,000 ft) high thrust ridges created by previous geologic activity along the fault had collapsed, generating
landslides several kilometers wide. One such landslide consisted of a single block of rock some 100 m high and 2 km long (300 ft by 1.25 mi). The momentum of the water displaced by tectonic uplift had also dragged massive slabs of rock, each weighing millions of tons, as far as 10 km (7 mi) across the seabed. An
oceanic trench several kilometres wide was exposed in the earthquake zone.
[33]The
TOPEX/Poseidon and
Jason 1 satellites happened to pass over the tsunami as it was crossing the ocean.
[34] These satellites carry
radars that measure precisely the height of the water surface; anomalies of the order of 50 cm (20 in) were measured. Measurements from these satellites may prove invaluable for the understanding of the earthquake and tsunami.
[35] Unlike data from
tide gauges installed on shores, measurements obtained in the middle of the ocean can be used for computing the parameters of the source earthquake without having to compensate for the complex ways in which close proximity to the coast changes the size and shape of a wave.
Tsunami characteristics
Animation of the tsunami caused by the earthquake showing how the tsunami radiated from the entire length of the 1,600
km (994
mi) rupture.
Scale showing the size of the tsunami waves that hit Indonesia.
The sudden vertical rise of the
seabed by several metres during the earthquake displaced massive volumes of water, resulting in a
tsunami that struck the coasts of the Indian Ocean. A tsunami which causes damage far away from its source is sometimes called a
teletsunami and is much more likely to be produced by vertical motion of the seabed than by horizontal motion.
[36]The tsunami, like all others, behaved very differently in deep water than in shallow water. In deep ocean water, tsunami waves form only a small hump, barely noticeable and harmless, which generally travels at a very high speed of 500 to 1,000 km/h (310 to 620 mph); in shallow water near coastlines, a tsunami slows down to only tens of kilometres an hour, but in doing so forms large destructive waves. Scientists investigating the damage in Aceh found evidence that the wave reached a height of 24 m (79 ft) when coming ashore along large stretches of the coastline, rising to 30 m (98 ft) in some areas when travelling inland.
[5]Radar satellites recorded the heights of tsunami waves in deep water: at two hours after the earthquake, the maximum height was 60 centimetres (2.0 ft). These are the first such observations ever made. Unfortunately these observations could not be used to provide a warning, since the satellites were not built for that purpose and the data took hours to analyze.
[37][38]According to
Tad Murty, vice-president of the
Tsunami Society, the total energy of the tsunami waves was equivalent to about five
megatons of
TNT (20
petajoules). This is more than twice the total explosive energy used during all of
World War II (including the two
atomic bombs), but still a couple of
orders of magnitude less than the energy released in the earthquake itself. In many places the waves reached as far as 2 km (1 mi) inland.
[39]
Tsunami wave field in the
Bay of Bengal one hour after the M=9.2 earthquake. View to the northwest.
Because the 1,600 km (994 mi) fault affected by the earthquake was in a nearly north-south orientation, the greatest strength of the tsunami waves was in an east-west direction.
Bangladesh, which lies at the northern end of the
Bay of Bengal, had very few casualties despite being a low-lying country relatively near the epicenter. It also benefited from the fact that the earthquake proceeded more slowly in the northern rupture zone, greatly reducing the energy of the water displacements in that region.
Coasts that have a landmass between them and the tsunami's location of origin are usually safe; however, tsunami waves can sometimes
diffract around such landmasses. Thus, the Indian state of
Kerala was hit by the tsunami despite being on the western coast of
India, and the western coast of Sri Lanka also suffered substantial impacts. Also distance alone was no guarantee of safety;
Somalia was hit harder than Bangladesh despite being much farther away.
Because of the distances involved, the tsunami took anywhere from fifteen minutes to seven hours (for
Somalia) to reach the various coastlines.
[40][41] The northern regions of the Indonesian island of Sumatra were hit very quickly, while Sri Lanka and the east coast of India were hit roughly 90 minutes to two hours later. Thailand was also struck about two hours later despite being closer to the epicentre, because the tsunami travelled more slowly in the shallow
Andaman Sea off its western coast.
The tsunami was noticed as far as
Struisbaai in
South Africa, some 8,500 km (5,282 mi) away, where a 1.5 m (5 ft) high tide surged on shore about 16 hours after the earthquake. It took a relatively long time to reach this spot at the southernmost point of Africa, probably because of the broad continental shelf off South Africa and because the tsunami would have followed the South African coast from east to west. The tsunami also reached
Antarctica, where tidal gauges at Japan's
Showa Base recorded oscillations of up to a metre, with disturbances lasting a couple of days.
[42]Some of the tsunami's energy escaped into the
Pacific Ocean, where it produced small but measurable tsunamis along the western coasts of North and South America, typically around 20 to 40 cm (7.9 to 15.7 in).
[43] At
Manzanillo,
Mexico, a 2.6 m (8.5 ft) crest-to-trough tsunami was measured. As well, the tsunami was large enough to be detected in
Vancouver,
British Columbia,
Canada. This puzzled many scientists, as the tsunamis measured in some parts of South America were larger than those measured in some parts of the Indian Ocean. It has been theorized that the tsunamis were focused and directed at long ranges by the
mid-ocean ridges which run along the margins of the continental plates.
[44]Signs and warnings
Maximum recession of tsunami waters at
Kata Noi Beach,
Thailand, before the third, and strongest, tsunami wave (sea visible in the right corner, the beach is at the extreme left), 10:25 a.m. local time.
Despite a lag of up to several hours between the earthquake and the impact of the tsunami, nearly all of the victims were taken completely by surprise. There were no
tsunami warning systems in the Indian Ocean to detect tsunamis or to warn the general populace living around the ocean. Tsunami detection is not easy because while a tsunami is in deep water it has little height and a network of sensors is needed to detect it. Setting up the communications infrastructure to issue timely warnings is an even bigger problem, particularly in a relatively poor part of the world.
Tsunami are much more frequent in the Pacific Ocean because of earthquakes in the "
Ring of Fire", and an effective tsunami warning system has long been in place there. Although the extreme western edge of the Ring of Fire extends into the Indian Ocean (the point where this earthquake struck), no warning system exists in that ocean. Tsunamis there are relatively rare despite earthquakes being relatively frequent in Indonesia. The last major tsunami was caused by the
Krakatoa eruption of 1883. It should be noted that not every earthquake produces large tsunamis; on March 28, 2005, a magnitude 8.7 earthquake hit roughly the same area of the Indian Ocean but did not result in a major tsunami.
In the aftermath of the disaster, there is now an awareness of the need for a tsunami warning system for the Indian Ocean. The
United Nations started working on an
Indian Ocean Tsunami Warning System and by 2005 had the initial steps in place. Some have even proposed creating a unified global tsunami warning system, to include the
Atlantic Ocean and
Caribbean.
The first warning sign of a possible tsunami is the earthquake itself. However, tsunami can strike thousands of kilometres away where the earthquake is only felt weakly or not at all. Also, in the minutes preceding a tsunami strike, the sea often recedes temporarily from the coast. Around the Indian Ocean, this rare sight reportedly induced people, especially children, to visit the coast to investigate and collect stranded fish on as much as 2.5 km (1.6 mi) of exposed beach, with fatal results.
[45] However, not all tsunami causes this "disappearing sea" effect. In some cases, there are no warning signs at all: the sea will suddenly swell without retreating, surprising many people and giving them little time to flee.
One of the few coastal areas to evacuate ahead of the tsunami was on the Indonesian island of
Simeulue, very close to the epicentre. Island folklore recounted an earthquake and tsunami in 1907, and the islanders fled to inland hills after the initial shaking yet before the tsunami struck.
[46] On Maikhao beach in northern
Phuket,
Thailand, a 10-year-old
British tourist named
Tilly Smith had studied tsunami in geography class at school and recognised the warning signs of the receding ocean and frothing bubbles. She and her parents warned others on the beach, which was evacuated safely.
[47] John Chroston, a biology teacher from Scotland, also recognised the signs at Kamala Bay north of Phuket, taking a busload of vacationers and locals to safety on higher ground.
Anthropologists had initially expected the
aboriginal population of the
Andaman Islands to be badly affected by the tsunami and even feared the endangered
Onge tribe could have been wiped out. Of the six native tribes only the Nicobarese, who had converted to Christianity and taken up agriculture in place of their previous
hunter-gatherer lifestyle, and mainland settlers suffered significant losses.
[48] Many of the
aboriginal tribes evacuated and suffered fewer casualties.
[49][50]Phases and wave form
USGS graphics showing the wave structure of the 2004 Indian Ocean tsunami. Red indicate a positive wave form while blue represent a negative wave form.
A tsunami can arrive at a coastline in one of two ways. First, there's the negative wave where the trough of the wave precedes the actual arrival of the crest or "wave" itself. Here, the common and better known warning sign of an impending tsunami strike is a rapidly receding sea followed by a sudden onrushing body of water traveling inland at high speed.
The second form in which a tsunami arrives is the positive wave or crest first. In this case, the warning signs are much more vague if any. The sea will usually start rising immediately rather slowly at first without the receding phase, much more like an on-coming high tide but instead of stopping at tidal level it will keep on rising faster and faster until the crest of the tsunami passes and continues moving inland. Therefore, the second form of tsunami waves are usually more dangerous owing to the fact that it can arrive without much warning giving residents less time to prepare and outrun the tsunami. These two types of tsunamis are usually generated simultaneously (in opposing direction of travel) by a
megathrust earthquake similar to the 2004 Indian Ocean earthquake.
Retreat-rise cycle (negative wave)
The tsunami was a succession of several waves, occurring in retreat and rise cycles with a period of over 30 minutes between each peak. The third wave was the most powerful and reached highest, occurring about an hour and a half after the first wave. Smaller tsunami continued to occur for the rest of the day.
[citation needed]Rise-retreat-rise cycle (positive wave)
If the crest of a tsunami arrives first, there won't be any recession. The sea level will increase rapidly to inundate everything in the path of the tsunami. This appears to be the case in countries such as Sri Lanka and India that lies to the west of the Andaman-Sumatra fault where the tsunami originates. After the first tsunami wave passed, water will then begin to flow back into the ocean receding at a quicker pace as the second wave arrives.
[citation needed] | Receding waters after the second tsunami, 10:20 a.m. | 3rd tsunami wave, 11:00 a.m. | 4th tsunami wave, 11:22 a.m. |
Death toll and casualties
According to the
U.S. Geological Survey a total of 227,898 people died (see table below for details).
[51] Measured in lives lost, this is one of the ten
worst earthquakes in recorded history, as well as the single worst tsunami in history. Indonesia was the worst affected area, with most death toll estimates at around 170,000.
[52] However, another report by health minister Fadilah Supari has estimated the death total to be as high as 220,000 in Indonesia alone, giving a total of 280,000 casualties.
[53]The tsunami caused serious damage and deaths as far as the east coast of
Africa, with the furthest recorded death due to the tsunami occurring at Rooi Els in
South Africa, 8,000 km (4,971 mi) away from the epicentre. In total, eight people in South Africa died due to abnormally high sea levels and waves.
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 because children were the least able to resist being overcome by the surging waters.
Oxfam went on to report that as many as four times more women than men were killed in some regions because they were waiting on the beach for the fishermen to return and looking after their children in the houses.
[54]In addition to the large number of local residents, up to 9,000 foreign tourists (mostly Europeans) enjoying the peak holiday travel season were among the dead or missing, especially people from the
Nordic countries. The European nation hardest hit may have been
Sweden, whose death toll was 543.
[55]States of emergency were declared in
Sri Lanka,
Indonesia, and the
Maldives. The
United Nations estimated at the outset that the relief operation would be the costliest in human history. Then
UN Secretary-General Kofi Annan stated that reconstruction would probably take between five and ten years. Governments and
non-governmental organisations feared that the final
death toll might double as a result of diseases, prompting a massive
humanitarian response. In the end, this fear did not materialise.
For purposes of establishing timelines of local events, the
time zones of affected areas are: UTC+3: (Kenya, Madagascar, Somalia, Tanzania); UTC+4: (Mauritius, Réunion, Seychelles); UTC+5: (Maldives); UTC+5:30: (India, Sri Lanka); UTC+6: (Bangladesh); UTC+6:30: (Cocos Islands, Myanmar); UTC+7: (Indonesia (western), Thailand); UTC+7: (Malaysia, Singapore). Since the earthquake occurred at 00:58:53
UTC, add the above offsets to find the local time of the earthquake.
Country where
deaths occurred | Deaths | Injured | Missing | Displaced |
|---|
| Confirmed | Estimated1 |
|---|
| Indonesia | 130,736 | 167,736 | N/A | 37,063[56] | 500,000+[57] |
| Sri Lanka2 | 35,322[58] | 35,322 | 21,411[58] | N/A | 516,150[58] |
| India | 12,405 | 18,045 | N/A | 5,640 | 647,599 |
| Thailand | 5,3953[59] | 8,212 | 8,457[60] | 2,817[59] | 7,000 |
| Somalia | 78 | 289[61] | N/A | N/A | 5,000[62] |
| Myanmar (Burma) | 61[56] | 400–600[63] | 45 | 200[64] | 3,200 |
| Maldives | 82[65] | 108[66] | N/A | 26 | 15,000+ |
| Malaysia | 68[67] | 75 | 299[68] | 6 | N/A |
| Tanzania | 10[69] | 13 | N/A | N/A | N/A |
| Seychelles | 3[70] | 3 | 57[70] | N/A | 200[71] |
| Bangladesh | 2 | 2 | N/A | N/A | N/A |
| South Africa | 24[72] | 2 | N/A | N/A | N/A |
| Yemen | 2[73] | 2 | N/A | N/A | N/A |
| Kenya | 1 | 1 | 2 | N/A | N/A |
| Madagascar | N/A | N/A | N/A | N/A | 1,000+[74] |
| Total | ~184,167 | ~230,210 | ~125,000 | ~45,752 | ~1.69 million |
|---|
|
Note: All figures are approximate and subject to change. The first column links to more details on specific countries.1 Includes those reported under 'Confirmed'. If no separate estimates are available, the number in this column is the same as reported under 'Confirmed'.
2 Does not include approximately 19,000 missing people initially declared by
Tamil Tiger authorities from regions under their control.
3 Data includes at least 2,464 foreigners.
4 Does not include South African citizens who died outside of South Africa (e.g., tourists in Thailand). For more information on those deaths, see
this Countries affected
Countries most affected by the tsunami, with the earthquake's epicenter.
The earthquake and resulting tsunami affected many countries in Southeast Asia and beyond, including
Indonesia,
Sri Lanka,
India,
Thailand, the
Maldives,
Somalia,
Myanmar,
Malaysia,
Seychelles and others. Many other countries, especially
Australia and those in
Europe, had large numbers of citizens traveling in the region on holiday. Both
Sweden and
Germany lost over 500 citizens each in the disaster.
Event in historical context
This
earthquake was the biggest in the
Indian Ocean in some 700 years, or since around A.D. 1400.
[75][76][77] In 2008, a team of scientists working on Phra Thong, a barrier island along the hard-hit west coast of
Thailand, reported evidence of at least three previous major tsunamis in the preceding 2,800 years, the most recent from about 550 to 700 years ago. A second team found similar evidence of previous tsunamis during the last 1,200 years in
Aceh, a province at the northern tip of
Sumatra. Radiocarbon dating of bark fragments in soil below the second sand layer led the scientists to estimate that the most recent predecessor to the 2004 tsunami probably occurred between A.D. 1300 and 1450.
[78]Deadliest earthquakes[1]| Rank | Name | Date | Location | Fatalities | Magnitude | Comments |
|---|
| 1 | "Shaanxi" | 01556-01-231556-01-23 | Shaanxi, China | 820,000 - 830,000 (est.)[79] | 8.0 | Estimated death toll in Shaanxi, China. |
|---|
| 2 | "Tangshan" | 01976-07-281976-07-28 | Tangshan, China | 242,419 to 779,000 | 7.5 | Estimated death toll as high as 779,000. |
|---|
| 3 | "Antioch" | 00525-05-21525-05-21 | Antioch, Turkey | 250000 [80] | VIII | Procopius (II.14.6), sources based on John of Ephesus. |
|---|
| 4 | "Gansu" | 01920-12-161920-12-16 | Ningxia–Gansu, China | 235,502[81] | 7.8 | Major fractures, landslides. |
|---|
| 5 | "Aleppo" | 01138-10-111138-10-11 | Aleppo, Syria | 230,000 | 8.5 | The figure of 230,000 dead is based on a historical conflation of this earthquake with earthquakes in November 1137 on the Jazira plain and the large seismic event of 30 September 1139 in the Azerbaijani city of Ganja. The first mention of a 230,000 death toll was by Ibn Taghribirdi in the fifteenth century.[82] |
|---|
| 6 | "Indian Ocean" | 02004-12-262004-12-26 | Sumatra, Indonesia | 230,000+[83][2] | 9.1 | Deaths from earthquake and resulting tsunami. |
|---|
| 7 | "Haiti" | 02010-01-122010-01-12 | Haiti | 222,570 | 7.0 | Estimate June 2010.[84] |
|---|
| 8 | "Great Kantō" | 01923-09-011923-09-01 | Kantō region, Japan | 142,000 | 7.9 | An earthquake which struck the Kantō plain on the Japanese main island of Honshū at 11:58 on the morning of September 1, 1923. Varied accounts hold that the duration of the earthquake was between 4 and 10 minutes. The quake had an epicenter deep beneath Izu Ōshima Island in Sagami Bay. It devastated Tokyo, the port city of Yokohama, surrounding prefectures of Chiba, Kanagawa, and Shizuoka, and caused widespread damage throughout the Kantō region.[85] The power and intensity of the earthquake is easy to underestimate, but the 1923 earthquake managed to move the 93-ton Great Buddha statue at Kamakura. The statue slid forward almost two feet.[86] Casualty estimates range from about 100,000 to 142,000 deaths, the latter figure including approximately 40,000 who went missing and were presumed dead. |
|---|
| 9 | "Ashgabat" | 01948-10-061948-10-06 | Ashgabat, Turkmenistan | 110,000 | 7.3 |
|
|---|
| 10 | "Genroku" | 01703-12-31 December 31, 1703 | Edo | 108,800+ | 8 | This earthquake shook Edo and killed an estimated 2,300 people. The earthquake is thought to have been an interplate earthquake whose focal region extended from Sagami Bay to the tip of the Bōsō Peninsula as well as the area along the Sagami Trough in the open sea southeast of the Boso Peninsula. This earthquake then resulted in a tsunami which hit the coastal areas of the Boso Peninsula and Sagami Bay. This caused more than 6,500 deaths, particularly on the Boso Peninsula. The Habu Pond on Izu Ōshima collapsed and it rushed into the sea. The tsunami was reported to have caused more than 100,000 fatalities. |
|---|
| 11 | "Lisbon" | 01755-11-011755-11-01 | Lisbon, Portugal | 10,000-100,000 | 7.3 | Includes several thousands of deaths in Morocco and Spain |
|---|
This
earthquake was the third most powerful earthquake recorded since 1900, and the confirmed
death toll is just under 200,000 due to the ensuing tsunami. The deadliest earthquakes since 1900 were the
Tangshan, China earthquake of 1976, in which at least 255,000 were killed; the earthquake of 1927 in
Xining,
Qinghai, China (200,000); the
Great Kanto earthquake which struck
Tokyo in 1923 (143,000); and the
Gansu, China, earthquake of 1920 (200,000). The deadliest known earthquake in history occurred in
1556 in Shaanxi, China, with an estimated death toll of 830,000, though figures from this time period may not be reliable.
[87]The 2004 tsunami is the deadliest in recorded history. Prior to 2004, the deadliest recorded tsunami in the
Pacific Ocean was in 1782, when 40,000 people were killed by a tsunami in the
South China Sea.
[88] The tsunami created by the 1883 eruption of
Krakatoa is thought to have resulted in 36,000 deaths. The most deadly tsunami between 1900 and 2004 occurred in 1908 in
Messina,
Italy, on the
Mediterranean Sea, where the earthquake and tsunami killed 70,000. The most deadly tsunami in the
Atlantic Ocean resulted from the
1755 Lisbon earthquake, which, combined with the toll from the actual earthquake and resulting fires, killed over 100,000.
The 2004 earthquake and tsunami combined have been described as the deadliest
natural disaster since either the 1976
Tangshan earthquake or the
1970 Bhola cyclone, or could conceivably exceed both of these. Because of uncertainty over death tolls, it might never be known for sure which of these natural disasters was the deadliest.
Possible human component in magnitude of damage
A town near the coast of
Sumatra lies in ruin on January 2, 2005. This picture was taken by a United States military helicopter crew from the USS
Abraham Lincoln that was conducting humanitarian operations.
Indonesians gather under an approaching helicopter to receive food and supplies.
In an opinion piece in the
Wall Street Journal, published five days after the tsunami, a journalist, Andrew Browne, argued that the human destruction of
coral reefs may have played a role in exacerbating the destruction caused by the tsunami. Many countries across Asia, including Indonesia, Sri Lanka and Bangladesh, have put forth efforts to destroy the coral surrounding their beaches, and instead make way for shrimp farms and other economic choices. On the
Surin Island chain of Thailand's coast, Browne argued, people may have been saved as the tsunami rushed against the coral reefs, lessening its impact. However, there were many fewer people on these islands, which helps explain the lower death toll. Many reefs areas around the Indian Ocean have been exploded with dynamite because they are considered impediments to shipping, an important part of the South Asian economy.
[89] Similarly, Browne argued that the removal of coastal
mangrove trees may have intensified the effect of the tsunami in some locations. He argued that these trees, which lined the coast but were removed to make way for coastal residences, might have lessened the force of the tsunami, in certain areas. Another factor, Browne argued, is the removal of coastal sand
dunes.
[89]Humanitarian, economic and environmental impact
A great deal of
humanitarian aid was needed because of widespread damage of the
infrastructure, shortages of food and water, and economic damage.
Epidemics were of special concern due to the high
population density and
tropical climate of the affected areas. The main concern of humanitarian and government agencies was to provide sanitation facilities and fresh drinking water to contain the spread of diseases such as
cholera,
diphtheria,
dysentery,
typhoid and
hepatitis A and
B.
There was also a great concern that the death toll could increase as disease and hunger spread. However, because of the initial quick response, this was minimized.
[90]In the days following the tsunami, significant effort was spent in
burying bodies hurriedly for fear of disease. However, the
public health risks may have been exaggerated, and therefore this may not have been the best way to allocate resources. The
World Food Programme provided food aid to more than 1.3 million people affected by the tsunami.
[91]Nations all over the world provided over US$7 billion in aid for damaged regions, with the governments of
Australia pledging US$819.9 million (including a US$760.6-million aid package for Indonesia),
Germany offering US$660 million,
Japan offering US$500 million,
Canada offering US$343 million,
Norway and the
Netherlands offering both US$183 million, the
United States offering US$35 million initially (increased to US$350 million), and the
World Bank offering US$250 million. Also Italy offered US$95 million, increased later to US$113 million of which US$42 million was donated by the population using the SMS system
[92] According to
USAID, the US has pledged additional funds in long-term U.S. support to help the tsunami victims rebuild their lives. On February 9, 2005, President Bush asked Congress to increase the U.S. commitment to a total of
$950 million. Officials estimated that billions of dollars would be needed. Bush also asked his father, former President George H. W. Bush, and former President Bill Clinton to lead a U.S. effort to provide private aid to the tsunami victims.
[93]In mid-March the
Asian Development Bank reported that over US$4 billion in aid promised by governments was behind schedule. Sri Lanka reported that it had received no foreign government aid, while foreign individuals had been generous.
[94] Many charities were given considerable donations from the public. For example, in the UK the public donated roughly £330,000,000 sterling (nearly US$600,000,000). This considerably outweighed the donation by the government and came to an average of about £5.50 (US$10) donated by every citizen.
In August 2006, fifteen local aid staff working on post-tsunami rebuilding were found executed in northeast Sri Lanka after heavy fighting, the main umbrella body for aid agencies in the country said. There had been reports and rumors that the local aid workers had been killed.
Economic impact
The impact on
coastal fishing communities and fisherfolk, some of the poorest people in the region, has been devastating with high losses of
income earners as well as boats and fishing gear.
[95] In Sri Lanka artisanal fishery, where the use of fish baskets, fishing traps, and spears are commonly used, is an important source of fish for local markets; industrial fishery is the major economic activity, providing direct employment to about 250,000 people. In recent years the fishery industry has emerged as a dynamic export-oriented sector, generating substantial foreign exchange earnings. Preliminary estimates indicate that 66% of the fishing fleet and industrial infrastructure in coastal regions have been destroyed by the wave surges, which will have adverse economic effects both at local and national levels.
[96]The tsunami created demand for fiberglass reinforced plastic catamarans in boatyards of Tamil Nadu.
[97]But some economists believe that damage to the affected national economies will be minor because losses in the tourism and fishing industries are a relatively small percentage of the
GDP. However, others caution that damage to infrastructure is an overriding factor. In some areas drinking water supplies and farm fields may have been contaminated for years by salt water from the ocean.
[98]Both the earthquake and the tsunami may have affected shipping in the
Malacca Straits by changing the depth of the seabed and by disturbing navigational buoys and old shipwrecks. Compiling new navigational charts may take months or years.
[99]Countries in the region appealed to tourists to return, pointing out that most tourist infrastructure is undamaged. However, tourists were reluctant to do so for psychological reasons. Even resorts on the Pacific coast of Thailand, which were completely untouched, were hit by cancellations.
Environmental impact
Tsunami inundation,
Khao Lak, North of
Phuket, Thailand ASTER Images and SRTM Elevation Model.
Beyond the heavy toll on human lives, the
Indian Ocean earthquake has caused an enormous environmental impact that will affect the region for many years to come. It has been reported that severe damage has been inflicted on
ecosystems such as
mangroves,
coral reefs,
forests, coastal
wetlands,
vegetation, sand
dunes and
rock formations, animal and plant
biodiversity and
groundwater. In addition, the spread of solid and liquid waste and industrial chemicals,
water pollution and the destruction of
sewage collectors and treatment plants threaten the environment even further, in untold ways. The environmental impact will take a long time and significant resources to assess.
[100]According to specialists, the main effect is being caused by poisoning of the
freshwater supplies and the soil by
saltwater infiltration and deposit of a
salt layer over arable land. It has been reported that in the Maldives, 16 to 17 coral reef atolls that were overcome by sea waves are totally without fresh water and could be rendered uninhabitable for decades. Uncountable wells that served communities were invaded by sea, sand and earth; and
aquifers were invaded through porous rock. Salted-over soil becomes sterile, and it is difficult and costly to restore for
agriculture. It also causes the death of plants and important soil micro-organisms. Thousands of rice, mango and banana plantations in Sri Lanka were destroyed almost entirely and will take years to recover. The
United Nations Environment Programme (UNEP) is working with governments of the region in order to determine the severity of the ecological impact and how to address it.
[101] UNEP has decided to earmark a US$1,000,000 emergency fund and to establish a Task Force to respond to requests for technical assistance from countries affected by the tsunami.
[102] In response to a request from the
Maldivian Government, the Australian Government sent ecological experts to help restore marine environments and coral reefs—the lifeblood of Maldivian tourism. Much of the ecological expertise has been rendered from work with the
Great Barrier Reef, in Australia's northeastern waters.
Other effects
A note signed by
George W. Bush, then President of the United States, his wife
Laura Bush, and former Presidents
George H. W. Bush and
Bill Clinton, expressing their condolences during a visit to the embassy of
Sri Lanka in
Washington, D.C., Monday, January 3, 2005. The President wrote, “We pray for the victims and families of this epic disaster. And the American government and American people are dedicated to helping you recover.”
Many health professionals and aid workers have reported widespread psychological trauma associated with the tsunami. Traditional beliefs in many of the affected regions state that a relative of the family must bury the body of the dead, and in many cases, no body remained to be buried.
The hardest hit area,
Aceh, is considered to be a religiously conservative
Islamic society and has had no tourism nor any Western presence in recent years due to
armed conflict between the
Indonesian military and
Acehnese separatists. Some believe that the tsunami was divine punishment for lay
Muslims shirking their daily prayers and/or following a materialistic lifestyle. Others have said that
Allah was angry that there were Muslims killing other Muslims in an ongoing conflict.
[103] Women in Aceh required a special approach from foreign aid agencies, and continue to have unique needs.
The widespread devastation caused by the tsunami led the main rebel group
GAM to declare a cease-fire on December 28, 2004, followed by the Indonesian government, and the two groups resumed long-stalled peace talks, which resulted in a peace agreement signed August 15, 2005. The agreement explicitly cites the tsunami as a justification.
[104]The extensive international media coverage of the tsunami, and the role of mass media and journalists in reconstruction, were discussed by editors of newspapers and broadcast media in tsunami-affected areas, in special video-conferences set up by the
Asia Pacific Journalism Centre.
[105]The December 26, 2004 Asian Tsunami left both the people and government of India in a state of heightened alert. On December 30, 2004, four days after the tsunami, the
Portland, Oregon-based company Terra Research notified the India government that its sensors indicated there was a possibility of 7.9 to 8.1 magnitude tectonic shift in the next 12 hours between
Sumatra and
New Zealand.
[106] In response, the India
Home Affairs minister announced that a fresh onslaught of deadly tidal waves were likely along the India southern coast and
Andaman and
Nicobar Islands, even as there was no sign of turbulences in the region.
[106] The announcement generated panic in the Indian Ocean region and caused thousands to flee their homes, which resulted in jammed roads.
[107] The announcement was a false alarm and the Home Affairs minister withdrew their announcement.
[107] On further investigation, the India government learned that the consulting company Terra Research was run from the home of a self-described
earthquake forecaster who had no telephone listing and maintained a website where he sold copies of his detection system.
[108] Three days after the announcement,
Indian National Congress president
Sonia Gandhi called
Science & Technology minister
Kapil Sibal to express her concern about Sibal's December 30 public warning being "
hogwash".
[109]Another result of the tsunami, respective toward Indian culture, was the water that washed away centuries of sand from some of the ruins of a 1,200-year-old lost city at
Mahabalipuram on the south coast of India. The site, containing such notable structures as a half-buried granite lion near a 7th century Mahablipuram temple and a relic depicting an elephant, is part of what archaeologists believe to be an ancient port city that was swallowed by the sea hundreds of years ago.
[110][111]The tsunami had a severe humanitarian and political impact in Sweden. The hardest hit country outside Asia, 543 Swedish tourists, mainly in Thailand, died. With no single incident having killed more Swedish people since the
battle of Poltava in 1709, the
cabinet of Göran Persson was heavily criticized for lack of action. The event was examined by an independent inquiry,
Katastrofkommissionen.
[citation needed]Info: 2004 Indian Ocean earthquake and tsunami
