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2004 Indian Ocean earthquake

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   The tsunami caused by the December 26, 2004 earthquake strikes Ao Nang,
   Thailand.
   Enlarge
   The tsunami caused by the December 26, 2004 earthquake strikes Ao Nang,
   Thailand.

   The 2004 Indian Ocean earthquake, known by the scientific community as
   the Sumatra-Andaman earthquake, was an undersea earthquake that
   occurred at 00:58:53 UTC (07:58:53 local time) December 26, 2004 with
   an epicentre off the west coast of Sumatra, Indonesia. The earthquake
   triggered a series of devastating tsunamis that spread throughout the
   Indian Ocean, killing large numbers of people and inundating coastal
   communities across South and Southeast Asia, including parts of
   Indonesia, Sri Lanka, India, and Thailand. Although initial estimates
   have put the worldwide death toll at over 275,000 with thousands of
   others missing, recent analysis compiled lists a total of 229,866
   persons lost, including 186,983 dead and 42,883 missing. The figure
   excludes 400 to 600 people who are believed to have perished in Myanmar
   which is more than that government's official figure of only 61 dead.
   The catastrophe is one of the deadliest disasters in modern history.
   The disaster is known in Asia and in the international media as the
   Asian Tsunami, and also called the Boxing Day Tsunami in Australia,
   Canada, New Zealand, and the United Kingdom as it took place on Boxing
   Day. Coincidentally, the tsunami occurred exactly one year after the
   2003 earthquake that devastated the southern Iranian city of Bam.

   The magnitude of the earthquake was originally recorded as 9.0 on the
   Richter scale, but has been upgraded to between 9.1 and 9.3. At this
   magnitude, it is the second largest earthquake ever recorded on a
   seismograph. This earthquake was also reported to be the longest
   duration of faulting ever observed, lasting between 500 and 600
   seconds, and it was large enough that it caused the entire planet to
   vibrate at least half an inch, or over a centimetre. It also triggered
   earthquakes in other locations as far away as Alaska.

   The earthquake originated in the Indian Ocean just north of Simeulue
   island, off the western coast of northern Sumatra. The resulting
   tsunami devastated the shores of Indonesia, Sri Lanka, India, Thailand
   and other countries with waves up to 30 m (100 ft). It 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 (5,000 mi) away from the epicentre. In total, eight
   people in South Africa died due to abnormally high sea levels and
   waves.

   The plight of the many affected people and countries prompted a
   widespread humanitarian response. In all, the worldwide community
   donated more than US$7 billion in humanitarian aid to those affected by
   the earthquake.

Earthquake characteristics

   Epicentre of the earthquake, just north of Simeulue Island
   Enlarge
   Epicentre of the earthquake, just north of Simeulue Island

   The earthquake was initially reported as moment magnitude, Mw 9.0.
   (Notice that this is not the so-called Richter scale or local magnitude
   scale, ML, which is known to saturate at higher magnitudes.) In
   February 2005 some scientists revised the estimate of the magnitude to
   9.3. Although the Pacific Tsunami Warning Centre 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 Mw 9.1 to 9.3. Dr. Hiroo Kanamori of the California
   Institute of Technology believes that Mw = 9.2 is a good representative
   value for the size of this great earthquake. Reference: EERI
   Publication 2006-06, page 14 [www.eeri.org]

   The hypocentre of the main earthquake was at 3.316°N, 95.854°E ( 3°19′N
   95°51.24′E), approximately 160 km (100 mi) west of Sumatra, at a depth
   of 30 km (19 mi) below mean sea level (initially reported as 10 km).
   The earthquake itself (apart from the tsunami) was felt as far away as
   Bangladesh, India, Malaysia, Myanmar, Thailand, Singapore and the
   Maldives.

   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. The
   December 2004 earthquake actually occurred within the Alpide belt.

   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). 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 ( Cascadia Earthquake, western U.S. and Canada, Juan de
   Fuca Plate and North American Plate). These are all believed to have
   been of greater than magnitude 9, but no accurate measurements were
   available at the time.

Tectonic plates

   The earthquake was unusually large in geographical extent. An estimated
   1,200 km (750 mi) of faultline slipped about 15 m (50 ft) along the
   subduction zone where the India Plate dives under the 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 the formation of a rupture about 400 km
   (250 mi) long and 100 km (60 mi) wide, located 30 km (19 mi) beneath
   the sea bed—the longest 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 changes from
   subduction to strike-slip (the two plates push 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.

   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 slips 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 crust above and trigger melt which 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 bed is
   estimated to have risen by several metres, displacing an estimated
   30 km³ (7 cu mi) of water and triggering devastating tsunami waves. The
   waves did not originate from a point source, as mistakenly depicted in
   some illustrations of their spread, but radiated outwards along the
   entire 1,200 km (750 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 bed significantly reduced the capacity of the
   Indian Ocean, producing a permanent rise in the global sea level by an
   estimated 0.1 mm.

Aftershocks and other earthquakes

   Locations of initial earthquake and all aftershocks measuring greater
   than 4.0 from December 26, 2004-January 10, 2005. The initial quake is
   indicated by the large star in the lower right square of the grid.
   (Credit: USGS)
   Enlarge
   Locations of initial earthquake and all aftershocks measuring greater
   than 4.0 from December 26, 2004- January 10, 2005. The initial quake is
   indicated by the large star in the lower right square of the grid.
   (Credit: USGS)

   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 of magnitude 8.7 was located off
   the Sumatran island of Nias. A debate arose among seismologists over
   whether the 2005 Sumatra earthquake should be considered an aftershock
   of the December 2004 event or a "triggered earthquake" (an earthquake
   brought about by a previous earthquake), as it was larger than typical
   aftershocks but on the same fault. Other aftershocks of up to magnitude
   6.6 continued to shake the region daily for up to three or four months.
   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. 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.

   An earthquake of magnitude 8.7 was reported shortly at 16:09:37 UTC
   (23:09:37 local time) on March 28, 2005, approximately at the same
   location (see 2005 Sumatran earthquake). It was likely a very large
   aftershock of the original earthquake. This earthquake had strong
   aftershocks of its own, including magnitude 6.0 and 6.1 earthquakes. At
   8.7 it ranks as the 7th largest earthquake since 1900. A 6.7 magnitude
   earthquake struck on April 10, 2005, at 10:29 UTC (17:29 local time)
   about 120 km (75 mi) south-west of the city of Padang.

   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. Geologists say
   that the eruption of Mount Talang in April 2005 is connected to the
   December earthquake.

Power of the earthquake

   The total energy released by the 2004 Indian Ocean earthquake has been
   estimated as 3.35 exajoules (3.35×10^18 joules). This is equivalent to
   over 930 terawatt hours, 0.8 gigatons of TNT, or about as much energy
   as is used in the United States in 11 days. However, the most reliable
   seismic energy release estimate, as of September 30, 2005, is 1.1×10^18
   joules. This corresponds to about 0.25 gigatons of TNT. The earthquake
   is estimated to have resulted in an oscillation of the Earth's surface
   of about 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. The entire
   Earth's surface is estimated to have moved vertically by up to 1 cm.

   The shift of mass and the massive release of energy very slightly
   altered the Earth's rotation. The exact amount is yet undetermined, but
   theoretical models suggest the earthquake shortened the length of a day
   by 2.68  microseconds (2.68 µs, or about one billionth of the length of
   a day), due to a decrease in the oblateness of the Earth. 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, or perhaps by up to 5
   or 6 cm (2.0 to 2.4 in). 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 can be up to 15  m
   (50 ft).

   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), may have
   moved south-west by up to 20 m (66 ft), and some early estimates said
   up to 36 m (118 ft). However, more accurate data released, more than a
   month following the earthquake, present a more manageable figure of
   20 cm (7.9 in). 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).

   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) west of Sumatra. 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.
   Previous activity on the fault over geological periods of time had
   created large thrust ridges, about 1,500 m high, which collapsed in
   places during the earthquake to produce large landslides several
   kilometres across. One landslide consisted of a single block of
   material some 100 m high and 2 km long (300 ft by 1.25 mi). The force
   of the displaced water was such that individual blocks of rock, massing
   millions of tons apiece, were dragged as much as 10 km (7 mi) across
   the seabed. An oceanic trench several kilometres wide was exposed in
   the earthquake zone.

   By a beneficial and remarkable coincidence, the TOPEX/Poseidon and
   Jason 1 satellites happened to pass over the tsunami as it was crossing
   the ocean. 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. 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 complex effects close to
   the coast. Inversion of this height data may help adjust the parameters
   for the source earthquake.

Tsunami characteristics

   Animation of the tsunami caused by the earthquake showing how the
   tsunami radiated from the entire length of the 1,200 kilometer (750 mi)
   rupture.
   Animation of the tsunami caused by the earthquake showing how the
   tsunami radiated from the entire length of the 1,200 kilometer (750 mi)
   rupture.

   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.

   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 (80 ft) when coming ashore along large stretches of the
   coastline, rising to 30 m (100 ft) in some areas when travelling
   inland.

   Radar satellites recorded the heights of tsunami waves in deep water:
   at two hours after the earthquake, the maximum height was 60  cm (2
   ft). These are the first such observations ever made. However, these
   observations could not have been used to provide a warning, because the
   satellites were not intended for that purpose and the data took hours
   to analyse.

   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 (1.24  mi) inland.

   Because the 1,200 km (745.6 mi) of faultline 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 epicentre. 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 is 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. 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 (5,300 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
   Syowa Base recorded oscillations of up to a meter, with disturbances
   lasting a couple of days.

   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).
   At Manzanillo, Mexico, a 2.6 m (8.5 ft) crest-to-trough tsunami was
   measured. 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 theorised that the tsunamis were
   focused and directed at long ranges by the mid-ocean ridges which run
   along the margins of the continental plates.

Signs and warnings

   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.

   Tsunamis 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.
   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.
   Enlarge
   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.

   The first warning sign of a possible tsunami is the earthquake itself.
   However, tsunamis can strike thousands of miles 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. People in Pacific regions are more familiar with tsunamis and
   often recognise this phenomenon as a sign to head for higher ground.
   However, 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.

   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. On Maikhao beach in northern Phuket, Thailand, a 10-year-old
   British girl named Tilly Smith had studied tsunamis 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. 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.

Retreat and rise cycle

   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 tsunamis continued to
   occur for the rest of the day.

   Second tsunami wave starting to retreat, Kata Noi Beach, Thailand,
   10:17 a.m.

   Receding waters after the second tsunami, 10:20 a.m.

   3rd tsunami wave, 11:00 a.m.

   4th tsunami wave, 11:22 a.m.

Damage and casualties

   The U.S. Geological Survey initially recorded the toll as
   283,100 killed, 14,100 missing, and 1,126,900 people displaced. Early
   news reports after the earthquake spoke of a toll in the hundreds, but
   the numbers rose steadily over the following week. However, more recent
   figures indicate that the actual casualties were 186,983 dead and
   42,883 missing, for a total of 229,866, as more and more displaced
   survivors have been found and name duplications eliminated from the
   lists of victims. Measured in lives lost, this is one of the ten worst
   earthquakes in recorded history, as well as the single worst tsunami in
   history.

   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.

   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 428 dead, with 116 missing.

   States of emergency were declared in Sri Lanka, Indonesia, and the
   Maldives. The United Nations has declared that the current relief
   operation will be the costliest ever. UN Secretary-General Kofi Annan
   has stated that reconstruction would probably take between five and ten
   years. Governments and non-governmental organisations fear the final
   death toll may double as a result of diseases, prompting a massive
   humanitarian response.

   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); UTC+6: (Bangladesh, Sri Lanka); UTC+6:30: (Cocos Islands,
   Myanmar); UTC+7: (Indonesia (western), Thailand); UTC+8: (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 Estimated^1
   Indonesia       130,736   167,736    —        37,063  500,000+
   Sri Lanka^2     35,322    35,322     21,411           516,150
   India           12,405    18,045     —        5,640   647,599
   Thailand        5,395^3   8,212      8,457    2,817   7,000
   Somalia         78        289        —        —       5,000
   Myanmar (Burma) 61        400-600    45       200     3,200
   Maldives        82        108        —        26      15,000+
   Malaysia        68–   69  75         299      6       —
   Tanzania        10        13         —        —       —
   Seychelles      3         3          57       —       200
   Bangladesh      2         2          —        —       —
   South Africa    2^4       2          —        —       —
   Yemen           2         2          —        —       —
   Kenya           1         1          2        —       —
   Madagascar      —         —          —        —       1,000+
   Total           ~184,168  ~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 (eg, tourists in Thailand). For more information on those
   deaths, see this

Countries affected

   Countries most affected by the 2004 Indian Ocean earthquake.
   Enlarge
   Countries most affected by the 2004 Indian Ocean earthquake.

   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.
   Countries like Sweden and Germany lost over 500 citizens in the
   disaster.

Casualties in historical context

   This earthquake was the fourth 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.
   Deadliest earthquakes
   Rank Earthquake     Country       Year Fatalities
   1    "Shaanxi"      China         1556 830,000
   2    "Indian Ocean" nr. Indonesia 2004 283,100
   3    "Tangshan"     China         1976 242,000
   4    "Aleppo"       Syria         1138 230,000
   5    "Gansu"        China         1920 c. 200,000

   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. 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 seem to be 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.

Human component in magnitude of damage

   A village 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.
   Enlarge
   A village 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.
   Enlarge
   Indonesians gather under an approaching helicopter to receive food and
   supplies.

   The human destruction of coral reefs played a significant role in 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, many people were saved as the tsunami rushed
   against the coral reefs protecting the islands. 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. Similarly, the removal of
   coastal mangrove trees is believed to have intensified the effect of
   the tsunami in some locations. These trees, which lined the coast but
   were removed to make way for coastal residences, might have blocked the
   force of the tsunami. Another factor is the removal of coastal sand
   dunes.

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 rise further
   as diseases and hunger spread. However, because of the initial quick
   response, this was minimised.

   In the days after the event, 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.

   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. 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.

   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. Lots of 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
   about £5.50 (US$10) donated by each and every citizen.

   In August 2006, fifteen local aid staff working on post-tsunami
   rebuilding have been 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. 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.

   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.

   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.

   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. One year after the tsunami hit, tourism is beginning to
   climb again, with a full recovery expected sometime in 2006.

Environmental impact

   Tsunami Inundation, Khao Lak, North of Phuket, Thailand ASTER Images
   and SRTM Elevation Model.
   Enlarge
   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.

   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. 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. 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 north-eastern
   waters.

Other effects

   A note signed by former United States Presidents George H. W. Bush and
   Bill Clinton, First Lady Laura Bush, and President George W. Bush
   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.”
   Enlarge
   A note signed by former United States Presidents George H. W. Bush and
   Bill Clinton, First Lady Laura Bush, and President George W. Bush
   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. Some psychologists interpret this as
   evidence of psychological trauma.

   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
   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. In what may be the most significant positive result of the
   tsunami, the widespread devastation 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.

   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.

   In another positive note of the tsunami, the water 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.

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