Effect of the 2004 Indian Ocean earthquake on IndiaFrom Wikipedia, the free encyclopedia

Countries affected by the 2004 Indian Ocean earthquake

According to official estimates in India, 10,136 people were killed and hundreds of thousands made homeless

when a tsunamitriggered by the 2004 Indian Ocean earthquake near the Indonesian island of Sumatra struck

the southern coast on 26 December 2004. The earthquake registered 9.0 on the moment magnitude scale, and

was the largest in five decades. It was followed by strong aftershocks[1] on the Andaman and Nicobar Islands.

Contents

  [hide] 

1 Affected states and regions

2 Meteorological and seismic reports

3 Ex gratia payments

4 See also

5 References

6 External links

7 Notes

Affected states and regions[edit]

The Andaman and Nicobar Islands comprise 572 islands (land masses at low and high tide), of which 38 are

inhabited by people from the mainland and indigenous tribes. The islands were just north of the

earthquake epicentre, and the tsunami reached a height of 15 metres (49 ft) in the southern Nicobar Islands.

The official death toll was 1,310, with about 5,600 missing. The unofficial death toll (including those missing

and presumed dead) was estimated at about 7,000.

The Great Nicobar and Car Nicobar islands were the worst hit among all the islands because of their proximity

to the quake and relatively flat terrain. Aftershocks rocked the area,[2]and one-fifth of the population of

the Nicobar Islands was reported dead, injured or missing.[3] Chowra Island lost two-thirds of its population of

1,500. Entire islands were submerged, and Trinket Island was divided in two.[4] Communications were cut to

the Nancowry group of islands, some of which were submerged.[5]

On Car Nicobar, 111 Indian Air Force personnel and their family members were washed away when the

tsunami severely damaged their air base.[6] St. Thomas Cathedral (also known as the John Richardson

church after John Richardson, a missionary and member of parliament) was washed away. The church,

established in 1930 was one of the oldest and prominent churches in the region. A cricket stadium named after

John Richardson and a statue dedicated to him were also washed away.[citation needed]

Most of the population of the Andaman Islands are people from the mainland, primarily West Bengal and Tamil

Nadu. The natives of the Andaman and Nicobar Islands are endangered tribal groups, such as

the Jarawa, Sentinelese, Shompen, Onge and the Great Andamanese. They are anthropologically-significant

as some of the world's most primitive tribes. Most have maintained their lifestyle for centuries, and government

policy is one of non-interference. Most of the native islanders reportedly survived the tsunami because they live

on higher ground or far from the coast.[7] The Onge (with a 2001 census population of

96), Jarawa (240), Sentinelese (39) and Great Andamanese (43) were reached by survey teams. The

Sentinelese, on an island reserve, are hostile to outsiders and shot arrows at helicopters sent to check on

them.[8][9][10] On the Nicobar Islands theNicobarese, a tribe with a Southeast Asian heritage (2001 population

28,653), lost about 656 lives with 3,000 missing. Surveys were conducted on the Shompen (2001 census count

of 398) located on Great Nicobar island.

India's only active volcano, Barren 1 (on Barren Island 135 km (84 mi) northeast of Port Blair), erupted on 30

December due to increased seismic activity. The population was evacuated, and there were no casualties.

Indira Point (6°45’10″N and 93°49’36″E), the southernmost point of the Great Nicobar Island and India itself,

subsided 4.25 metres (13.9 ft) in the tsunami and its lighthouse was damaged.

2004 Indian Ocean earthquake and tsunamiFrom Wikipedia, the free encyclopedia

2004 Indian Ocean earthquake

Tsunami strikes Ao Nang, Thailand.

Date 00:58:53, 26 December 2004 (UTC)[1]

Magnitude 9.1–9.3 Mw[1]

Depth 30 km (19 mi)[1]

Epicenter3.316°N 95.854°ECoordinates: 3.316°N

95.854°E[1]

Type Undersea (subduction)

Countries or

regions

Indonesia (mainly in Aceh)

Sri Lanka

India (mostly in Tamil Nadu)

Thailand

Maldives

Somalia

Tsunami Yes

Casualties 230,210 – 280,000 deaths[2][3][4]

The 2004 Indian Ocean earthquake was an undersea megathrust earthquake that occurred at

00:58:53 UTC on Sunday, 26 December 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.[5][6] The

resulting tsunami was given various names, including the 2004 Indian Ocean tsunami, South Asian

tsunami, Indonesian tsunami, the Christmas tsunami and the Boxing Day tsunami.[7]

The earthquake was caused when the Indian Plate was subducted by the Burma Plate 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 ft) high.[8] It

was one of the deadliest natural disasters in recorded history. Indonesia was the hardest-hit country, followed

by Sri Lanka, India, and Thailand.

With a magnitude of Mw 9.1–9.3, it is the third largest earthquake ever recorded on a seismograph. The

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 centimetre (0.4 inches)[9] and triggered other earthquakes as far away

as Alaska.[10] Its epicentre was between Simeulue and mainland Indonesia.[11]The plight of the affected people

and countries prompted a worldwide humanitarian response. In all, the worldwide community donated more

than $14 billion (2004 US$) in humanitarian aid.[12]

Contents

  [hide] 

1   Earthquake characteristics

o 1.1   Tectonic plates

o 1.2   Aftershocks and other earthquakes

o 1.3   Energy released

2   Tsunami characteristics

o 2.1   Signs and warnings

3   Death toll and casualties

o 3.1   Countries affected

o 3.2   Event in historical context

4   Humanitarian, economic and environmental impact

o 4.1   Economic impact

o 4.2   Environmental impact

o 4.3   Other effects

5   See also

6   References

7   External links

Earthquake characteristics

The earthquake was initially documented as moment

magnitude 8.8. In February 2005 scientists revised

the estimate of the magnitude to 9.0.[13] 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 Mw 9.1–9.3. 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.[14]

The hypocentre of the main earthquake was

approximately 160 km (100 mi), in the Indian Ocean

just north of Simeulueisland, off the western coast of

northern Sumatra, at a depth of 30 km (19 mi) below

mean sea level (initially reported as 10 km (6.2 mi)).

The northern section of the Sunda megathrust,

ruptured; the rupture having a length of 1,300 km

(810 mi).[11] The earthquake (followed by the

tsunami) was felt simultaneously

in Bangladesh, India, Malaysia, Myanmar,Thailand, Singapore and the Maldives.[15] Splay faults, or secondary

"pop up faults", caused long, narrow parts of the sea floor to pop up in seconds. This quickly elevated the

2004 Indian Oceanearthquake

Animation of tsunami caused by the earthquake showing how it

radiated from the entire length of the 1,600 km (990 mi) rupture

Events

Timeline

Countries affected :

Indonesia

Sri Lanka

India

more...

Response

Humanitarian

See also

Warning System

Library damage

2005 Sumatra earthquake

V

T

E

height and increased the speed of waves, causing the complete destruction of the nearby Indonesian town

of Lhoknga.[16]

The epicentre of the earthquake, just north of Simeulue Island.

Indonesia lies between the Pacific Ring of Fire along the north-eastern islands adjacent to New Guinea, and

the Alpide beltthat runs along the south and west from Sumatra, Java, Bali, Flores to Timor.

Great earthquakes such as the Sumatra-Andaman event, which are invariably associated

with megathrust events insubduction zones, have seismic moments that can account for a significant fraction of

the global earthquake moment across century-scale time periods. 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. Mw 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 earthquakes of magnitude 9.0 or greater were off Kamchatka, Russia, on 4 November 1952

(magnitude 9.0)[17] and Tōhoku, Japan (magnitude 9.0) in March 2011. Each of these megathrust

earthquakes also spawned tsunamis in the Pacific Ocean. However, the death toll from these was significantly

lower, primarily because of the lower population density along the coasts near affected areas and the much

greater distances to more populated coasts and also due to the superior infrastructure and warning systems in

MEDCs (More Economically Developed Countries) such as Japan.

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) and1700 (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

Main article: Plate tectonics

A pie chart comparing the seismic moment release for the largest earthquakes from 1906 to 2005 compared to all other

earthquakes for the same period

The megathrust earthquake was unusually large in geographical and geological extent. An estimated 1,600

kilometres (1,000 mi) of fault surface slipped (or ruptured) about 15 metres (50 ft) along the subduction zone

where the Indian 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 kilometres

(250 mi) long and 100 kilometres (60 mi) wide, located 30 kilometers (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 kilometres per second (1.7 miles per second) (10,000 km/h or 6,200 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) (7,500 km/h or 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).

The Indian 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 centimetres per year (2.4 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 cubic kilometres (7.2 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-kilometre

(1,000 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 millimetres (0.004 in).[18]

Aftershocks and other earthquakes

Locations of initial earthquake and all aftershocks measuring greater than 4.0 from 26 December 2004 to 10 January 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 magnitude 8.7 2005 Sumatra earthquake, which

originated off the coast of the Sumatran island of Nias, is not considered an aftershock, despite its proximity to

the epicenter, and was most likely triggered by stress changes associated with the 2004 event.[19] 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.[20] 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 subantarctic 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.[21] 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 26 December 2003.[7]

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 Sumatra 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 1.1×1017 joules,[24] or 26 megatons of TNT. This energy

is equivalent to over 1500 times that of the Hiroshima atomic bomb, but less than that of Tsar Bomba, the

largest nuclear weapon ever detonated. However, the totalwork done MW (and thus energy) by this quake was

4.0×1022 joules (4.0×1029 ergs),[25] the vast majority underground. This is over 360,000 times more than its ME,

equivalent to 9,600 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 1.08×1020 J.

The only recorded earthquakes with a larger MW were the 1960 Chilean and 1964 Alaskan quakes, with

2.5×1023 joules (250 ZJ) and 7.5×1022 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 20 µm (0.02 mm;

0.0008 in) 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 hugeRayleigh (surface) elastic waves that

exceeded 1 cm (0.4 in) 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 theoblateness of the Earth.[28] It also caused the Earth to minutely

"wobble" on its axis by up to 2.5 cm (0.98 in) in the direction of 145° east longitude,[29] or perhaps by up to 5 or

6 cm (2.0 or 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 (120 ft), but

more accurate data released more than a month after the earthquake found the movement to be about 20 cm

(8 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 ft 1 in)

and to have sunk by 1 m (3 ft 3 in).[32]

In February 2005, the Royal Navy vessel HMS   Scott  surveyed the seabed around the earthquake zone, which

varies in depth between 1,000 and 5,000 m (550 and 2,730 fathoms; 3,300 and 16,400 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-metre-high (5,000 ft) 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 (6 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

NOAA's Tsunami travel Time (TTT) map for the 2004 Indian Ocean tsunami. The TTT map calculates the first-arrival travel

times of the tsunami, following their generation at the earthquake epicenter. NOTE that the Maps do not provide the height

or the strength of the wave, only the arrival times. The number tags represent hours after the initial event. Map contours

represent 1-hour intervals. Red indicates 1-4 hour arrival times, Yellow indicates 5-6 hour arrival times, Green indicates 7-14

hour arrival times, and Blue indicates 15-21 hour arrival times. Maps were generated from earthquake epicenters in the

NGDC Global Historical Tsunami Database using NGDC 2-Minute Gridded Global Relief Data bathymetry. The map was

created through models based on quality-controlled source data, and an integration of many data sets together.

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 ateletsunami 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 per 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 metres (80 ft) when coming ashore along large

stretches of the coastline, rising to 30 metres (100 ft) in some areas when travelling inland.[8]

Radar satellites recorded the heights of tsunami waves in deep water: at two hours after the earthquake, the

maximum height was 60 centimetres (2 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 fivemegatons of TNT (20 petajoules). This is more than twice the total explosive energy

used during all of World War II (including the twoatomic 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 (1.2 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 (1,000 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 sometimesdiffract 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, as 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 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 (5,300 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

reachedAntarctica, where tidal gauges at Japan's Showa Base recorded oscillations of up to a metre (3 ft 3 in),

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 ft 6 in) 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 am 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.

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 28 March 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 tsunamis cause 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 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 already depopulated Onge tribecould have been wiped out.[48] Many of

the aboriginal tribes evacuated and suffered fewer casualties.[49][50] Oral traditions developed from previous

earthquakes helped the aboriginal tribes escape the tsunami. For example, the folklore of the Onges talks of

"huge shaking of ground followed by high wall of water". Almost all of the Onge people seemed to have

survived the tsunami.[51]

Death toll and casualties

Chennai's Marina Beach after the tsunami.

According to the U.S. Geological Survey a total of 227,898 people died (see table below for details).

[1] 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 Siti Fadilah Supari, the Indonesian Minister of Health at the time, estimated the

death total to be as high as 220,000 in Indonesia alone, giving a total of 280,000 casualties.[4]

The tsunami caused serious damage and deaths as far as the east coast of Africa, with the farthest 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.

Relief agencies reported that one-third of the dead appeared to be children. This was 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.[53]

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.[54]

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.

Patong Beach, Thailand, after the tsunami

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+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 wheredeaths

occurredConfirmed Estimated1 Injured

Missing

Displaced

Indonesia 130,736 167,799 n/a 37,063 500,000+[55]

Sri Lanka2 35,322[56] 35,322 21,411[56] n/a 516,150[56]

India 12,405 18,045 n/a 5,640 647,599

Country wheredeaths

occurredConfirmed Estimated1 Injured

Missing

Displaced

Thailand 5,3953[57] 8,212 8,457[58] 2,817[57] 7,000

Somalia 78 289[59] n/a n/a 5,000[60]

Myanmar (Burma) 61 400–600[61] 45 200[62] 3,200

Maldives 82[63] 108[64] n/a 26 15,000+

Malaysia 68[65] 75 299[66] 6 n/a

Tanzania 10[67] 13 n/a n/a n/a

Seychelles 3[68] 3 57[68] n/a 200[69]

Bangladesh 2 2 n/a n/a n/a

South Africa 24[70] 2 n/a n/a n/a

Yemen 2[71] 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+[72]

Total ~184,167 ~230,273 ~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.

Main article: Countries 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. Sweden lost 543 citizens in the disaster, while Germanyhad 539 identified victims.

Event in historical context

See also: Library damage resulting from the 2004 Indian Ocean earthquake

The last major tsunami in the Indian Ocean was about A.D. 1400.[73][74] 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 700 years ago. A second

team found similar evidence of previous tsunamis 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.[75]

The 2004 earthquake and tsunami combined are the world's deadliest natural disaster since the

1976 Tangshan earthquake. This earthquake was the third most powerful earthquake recorded since 1900.

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 as reliable.[76]

The 2004 tsunami is the deadliest in recorded history. Prior to 2004, the tsunami created in both Indian and

Pacific Ocean waters by the 1883 eruption of Krakatoa, thought to have resulted in anywhere from 36,000 to

120,000 deaths, had probably been the deadliest in the region. In 1782 about 40,000 people are thought to

have been killed by a tsunami (or a cyclone) in the South China Sea.[77] The most deadly tsunami prior to 2004

was Italy's 1908 Messina Earthquake on the Mediterranean Sea where the earthquake and tsunami killed

about 123,000. [78]

Humanitarian, economic and environmental impact

Main article: Humanitarian response to the 2004 Indian Ocean earthquake

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.[79]

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.[80]

Further information: Health risks from dead bodies

Nations all over the world provided over US$14 billion in aid for damaged regions,[81] 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[82] According to USAID, the US has pledged additional funds in long-term U.S. support to help the

tsunami victims rebuild their lives. On 9 February 2005, President Bush asked Congress to increase the U.S.

commitment to a total of US$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.[83]

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.[84] 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 level of damage to the economy resulting from the tsunami depends on the scale examined. While local

economies were devastated, the overall impact to the national economies was minor. The two main

occupations affected by the tsunami were fishing and tourism.[85] The impact on coastal fishing

communities and the people living there, some of the poorest in the region, has been devastating with high

losses of income earners as well as boats and fishing gear.[86] 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.[87]

While the tsunami destroyed many of the boats vital to Sri Lanka's fishing industry, it also created demand for

fiberglass reinforced plastic catamarans in boatyards of Tamil Nadu. Since over 51,000 vessels were lost to the

tsunami, the industry boomed. However, the huge demand has led to lower quality in the process, and some

important materials were sacrificed to cut prices for those who were impoverished by the tsunami.[88]

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.[89] Even though only costal regions were

directly affected by the waters of the tsunami, the indirect effects have spread to inland provinces as well. Since

the media coverage of the event was so extensive, many tourists cancelled vacations and trips to that part of

the world, even though their travel destinations may not have been affected. This ripple effect could especially

be felt in the inland provinces of Thailand, such as Krabi, which acted like a starting point for many other tourist

destinations in Thailand.[90]

Both the earthquake and the tsunami may have affected shipping in the Malacca Straits, which separate

Malaysia and the Indonesian island of Sumatra, by changing the depth of the seabed and by disturbing

navigational buoys and old shipwrecks. In one area of the Strait, water depths were previously up to 4,000 feet,

and are now only 100 feet in some areas, making shipping impossible and dangerous. These problems also

made the delivery of relief aid more challenging. Compiling new navigational charts may take months or years.

However, officials hope that piracy in the region will drop off as a result of the tsunami.[91]

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 beach resorts in parts of Thailand

which were completely untouched by the tsunami were hit by cancellations.[92]

Environmental impact

Tsunami inundation, Khao Lak, North ofPhuket, 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.[93]

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 completely 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. On the island's east coast, the tsunami contaminated wells on which many villagers relied for

drinking water. The Colombo-based International Water Management Institutemonitored the effects of saltwater

and concluded that the wells recovered to pre-tsunami drinking water quality one and a half years after the

event.[94] IWMI developed protocols for cleaning wells contaminated by saltwater; these were subsequently

officially endorsed by theWorld Health Organization as part of its series of Emergency Guidelines.[95]

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.[96]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.[97] 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

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. Women in Aceh required a special approach

from foreign aid agencies, and continue to have unique needs.

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 conflictbetween 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.[98] Saudi cleric Muhammad Al-

Munajjid attributed it to divine retribution against non-Muslim vacationers "who used to sprawl all over the

beaches and in pubs overflowing with wine" during Christmas break.[99]

The widespread devastation caused by the tsunami led the main rebel group GAM to declare a cease-fire on

28 December 2004 followed by the Indonesian government, and the two groups resumed long-stalled peace

talks, which resulted in a peace agreement signed 15 August 2005. The agreement explicitly cites the tsunami

as a justification.[100]

In a poll conducted in 27 countries by GlobeScan for BBC World Service, 15 percent of respondents named the

tsunami the most significant event of the year. Only the Iraq Warwas named by as many respondents.[101] 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.[102]

The 26 December 2004 Asian Tsunami left both the people and government of India in a state of heightened

alert. On 30 December 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.[103] 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.

[103] The announcement generated panic in the Indian Ocean region and caused thousands to flee their homes,

which resulted in jammed roads.[104] The announcement was a false alarm and the Home Affairs minister

withdrew their announcement.[104] 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.[105] Three days after

the announcement, Indian National Congress president Sonia Gandhicalled Science &

Technology minister Kapil Sibal to express her concern about Sibal's 30 December public warning being

"hogwash".[106]

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 atMahabalipuram 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.[107][108]

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.

Apung 1, a 2600 ton ship, was flung some 2–3 km inland by the tsunami, and has become a popular tourist

attraction in Banda Aceh.

Effects of TsunamisTsunamis are some of the most devastating natural disasters known to man. Think of a flood with its source being an ocean and you can grasp a little of how much devastation tsunamis can create. For most people who live in land the greatest threat is from overflowing rivers and creeks. Normally extraordinarily heavy rainfall causes rivers and and other waterways to overflow. The excess water creates deadly currents and sweep away people, causing them to drown. It also does a lot of damage in the initial surge and then with standing water. A tsunami has all of these detrimental effects plus the added destructive power crashing waves.

As you many know a tsunami is caused by a strong earthquake on the ocean bed. The vibrations travel through the water traveling sometimes thousands of kilometers. If you were on the water or deep sea diving in SCUBA gear you would not notice much probably just rough waves or a momentarily strong downward pull if you were underwater. However, a tsunami gains its true destructive power as it approaches land. The water level becomes shallower causing the waves caused by the earthquake to compress and combine. This is what creates the massive and destructive waves that cause so much destruction.

Imagine over several tons worth of water either falling on you or surging towards you. You would have a better chance at the Running of the Bulls. The waves not only sweep people away, but can also destroy even well built structures. The costs to human life can also be devastating. The deadliest tsunamis in recorded history was the Christmas tsunamis of 2004 in the Indian Ocean. On December 24, 2004, a massive 9.2 earthquake occurred of the

island of Sumatra. It created a deadly series of tsunamis that swept Indonesia, India, Madagascar, and Ethiopia. The death toll was estimated to be in the neighborhood of 300,000 to 350,000. This was one of the greatest losses of life due to a major natural catastrophe in modern history.

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The immediate destruction is only the beginning of the damage. After the waters retreated there was the elevated risk of disease created by stagnant and contaminated water. Since most tsunamis occur south of the Equator and In the Pacific this only raises the risk of disease further.

There can also be more interesting effects that deal solely with scientific curiosity. The Christmas tsunami was so powerful it actually sped up the rotation of the Earth reducing the length of its sidereal day. The earthquake that spawned it also caused the Earth to vibrate all over by as much as 1 cm.

If you enjoyed this article there are several others that you will enjoy on Universe Today. There is a great article on how GPS can be used to predict tsunamis. There is also an article about famous earthquakes.

There are also great resources online. There is PBS Nova has web page that is a companion site to the documentary it did on the Christmas Indian Ocean Tsunamis. The USGS   also has a great article that analyzes the tsunamis.

The Psychological Impacts of the 2004 Indian Ocean TsunamiBy: Kristi Free

How would you feel if you lived through a natural disaster? How would you feel afterwards?  Could you imagine your life being turned around, losing your house, losing your possessions, and losing loved ones in a matter of minutes? Many people faced these questions after the 2004 Indian Ocean tsunami hit and changed their lives as they knew it.  Natural disasters can cause detrimental effects on the health and emotional well being on those who are impacted by them.  The fear that those who survive face after the disaster can cause them to develop psychological problems.  They may feel anxiety, stress, and panic when

thinking about the disaster, reflecting back on it, or even just encountering a new situation that is similar to the previous disaster.  Survivors of natural disasters, such as the 2004 tsunami, undergo psychological distress that will harm their mental health and there are certain risks, symptoms, emotional responses, and coping mechanisms that are associated with this distress.

While the majority of survivors recover from disasters with no long lasting effects on their psychological health, a fraction of the survivors will experience long-term psychological distress.  The level of distress is often dependent on both predisaster and postdisaster factors.  Pretrauma psychological symptoms are often good indicators of postdisaster symptoms.  Also, the extent to which the disaster affected you plays a large role in postdisaster symptoms.  Depending on how much financial loss, material destruction, education levels, age, and the level and quality of social support will lead to different amounts of distress after the disaster.  Impaired mental health is also due to the direct impact of the disaster, such as physical injury, the loss of loved ones, and the perception of life threat.  A study was done on a number of tourists who were in Stockholm, one of the hardest hit cities, to determine their psychological distress based on different types of psychological exposure (Wahlsrtom, pg 463-470).  The study was done fourteen months after the tsunami and showed that the more severely exposed groups faced more psychological distress.  It showed that the perception of life threat alone was associated with both general and posttraumatic distress.  Also, the lower the education levels, the higher the percentage of posttraumatic stress.  The younger age groups experienced more general psychological distress while females experienced both types of stress more than males (Wahlsrtom, pg 463-470).

Sumatrans waving to MH-60S Knighthawk

One type of psychological distress that occurs after natural disasters is posttraumatic stress.  Posttraumatic stress disorder is a severe anxiety disorder that can develop after exposure to any event and results in psychological trauma.  Diagnostic symptoms for PTSD include re-experiencing the original trauma through flashbacks or nightmares, avoidance of stimuli associated with the trauma, and increased arousal(Kumar, pg 99-101).  Due to the major destruction of India, the loss of life, and relocations, many people developed this disorder.  A study was conducted in a coastal fishing village in Tamil Nadu, India to determine the prevalence and risk factors that are associated with it.  A community-based household survey was given to the adults in the village.  The survey was given two months after the disaster hit.  The Harvard Trauma Questionnaire was used to assess posttraumatic stress disorder.  The prevalence of the disorder was 12.7 percent.  Some of the most common symptoms those who were facing this disorder experienced were reoccurring thoughts and sleep disturbances.  Less prevalent symptoms included irritability and emotional numbness.  Out of those who sought help from a psychiatrist, 48.9 percent were diagnosed with major depressive disorder and 31.9 percent were diagnosed with posttraumatic stress disorder.  Some of the risk factors for developing PTSD after the tsunami included those with no household incomes, women, those who experienced personal injury, and those who lost a family member due to the disaster (Kumar, pg 99-101).

While most the studies are conducted on adults, the distress and posttraumatic stress in children also need to be analyzed.  About 23-30

percent of children develop full symptoms of posttraumatic stress disorder in the first six months after disasters.  Developing PTSD increases their risk of other disorders and the impairment of psychological functioning.  One of the most critical factors in their chance of developing PTSD is the personal perception of life threat. Other factors include a cultural perspective on the disaster and family support (Brushan, pg 245-257).  A study was conducted one year after the tsunami to determine the prevalence of PTSD in children.  It was conducted in the Akkaraipettai village in India.  The age of the children involved in the study ranged from ten to sixteen years old and they were all in middle school.  The two tests used were the Impact of Events Scale (IES) and the Children’s Revised Impact of Events Scale (CRIES) to identify the prevalence of PTSD.  Also using the Pediatric Emotional Distress Scale (PEDS), the results showed that the disaster caused emotional distress to the children even a year after it occurred.  94.2 percent of males and all females scored high on anxiety withdrawal and scored equally high on fearfulness.  Another study found that 13 percent developed posttraumatic stress disorder while 48 percent reported re-experiencing and arousal symptoms.  It also found that the loss of a family member is a major contributing factor of children developing emotional distress and PTSD (Brushan, pg 245-257).

Man searching through rubble in Meulaboh

Children who are indirectly exposed to natural disasters will show emotional responses to them.  One way to cope with such disasters is through art therapy.  One study used sandplay to visually see the emotional responses of a group of immigrant and refugee preschoolers living in South Asia only two weeks after the tsunami hit.  Flooding is a dangerous disaster because it can occur without any warning and is very destructive.  Preschoolers typically demonstrate regressive behaviors, such as clinging, thumb sucking, bedwetting, whimpering, loss of appetite, frightened facial expressions, and night terrors (Lacroix, pg 99-113).  This study examined how children relive trauma through play.  Although they were indirectly exposed to the disaster, their parent’s reactions greatly influenced theirs, but very few children are at risk of developing posttraumatic stress disorder.  Also, the media’s portrayal of the event has a negative impact on the children’s emotional responses because they absorb the visual images and information without cognitively processing it.  One attempt to allow children to cope with the disaster is sandplay, in which they can master their feelings by creating scenes in a sand tray using human characters, religious figures, animals, and objects.  In this experiment, 29 percent of the children represented the tsunami.  9 percent directly represented it, with the tsunami itself, devastating floods, and babies who ended up in trees and rooftops.  20 percent indirectly represented the tsunami with sea monsters devouring people and animals and other cars and houses hidden in the sand.  Some of the verbal representations included, “This is a tsunami,” “Everyone is dead,” and “People died in the water.”  The children were enthusiastic about their creations but the main negative emotions were sadness, followed by anxiety.  Sandplay helps the children to come to terms and understand the disaster (Lacroix, pg 99-113).

Adults also had very profound emotional responses to the tsunami.  In a village of Tamil Nadu, emotional responses were obtained by the survivors.  They varied based on their occupation, how the tsunami affected their daily lives, and if they or someone they loved was injured or lost.  One fisherman reported that the worst of his losses was the loss

of his trust over the all-providing mother sea.  Both men and women considered that the loss of their pride had more psychological impact than anything else.  Parents who lost children were inconsolable in their anguish and widows felt widowship symbolized their fall from grace and loss of security.  After the tsunami many people’s attitudes changed towards life.  Many housewives felt that men were more fatalistic after the disaster.  Parents believed that the tragedy shattered their dreams about their children’s career.  Also, their financial standings changed and many felt they became more economical and now have to plan for their finances. Teenager’s attitudes also changed as some believed they now have to be more serious and responsible rather than easygoing (Rajkumar, pg 844-853).

Woman & child in Meulaboh

Survivors of natural disasters explore several coping methods to try to resolve their psychological distress.   A study was conducted in a coastal village of Tamil Nadu to gain insight on the coping mechanisms used by the local communities nine months after the tsunami.  Participants were selected based on their social roles and included fisherman, housewives, community leaders, and members of the youth.  The survivors valued their unique, individual, social and spiritual coping strategies more than formal health services.  They had a tendency to collectivize their

personal sorrow.  They viewed themselves as an integral part of a larger traumatized society and not as lonely sufferers.  The village has frequent social gatherings to remember the deceased.  Those who lost loved ones adopted a custom of planting and caring for coconut saplings to remember them.  They offered foods favored by their loved ones who died to the saplings.  Many children sacrificed school to help earn livelihoods for their families.  Also, the community expressed four themes in their spiritual coping strategies: requiems, rituals, religious beliefs, and spiritual seeking.  Grief and mourning were loud and publicly demonstrated.  Requiems were held with traditional music and social customs.  They believed in the existence of an immortal soul that would re-incarnate them into higher forms of life.  Most people claimed that their religious beliefs were the most important factor contributing to their survival. Therefore their religious practices were strengthened by the tsunami.  This study showed that coping mechanisms are shaped by ethno-cultural variations (Rajkumar, pg 844-853).

The 2004 tsunami that hit the Indian Ocean had detrimental effects on the psychological health on those who survived the disaster, and even those who heard about it through the media.  Anxiety, psychological distress, and even posttraumatic stress disorder became prevalent in those who were affected.  The degree in which they were affected was dependent on many factors.  Those who were more severely emotional hurt were those who had lower education levels, less financial support, less family and social support, women, youth, those who were personally injured, or those who lost love ones because of the tsunami.  Many coping mechanisms are available for those who experience psychological distress, including art therapy, religious beliefs, community gatherings, and professional help.

Indian Ocean on tsunami alert after quakes

A tsunami warning is in effect in the Indian Ocean following powerful earthquakes off the coast of

Indonesia's Aceh province, prompting evacuations from coastal regions and alarm in areas struck by

a devastating wave in 2004.

Wednesday's first quake was measured at a magnitude of 8.6, according to the US Geological

Survey, which revised down an earlier 8.9 estimate.

US seismologists reduced the area under watch for a possible tsunami.

The US Pacific Tsunami Warning Center in Hawaii said a tsunami watch now is in effect for

Indonesia, India, Sri Lanka, Maldives and the British Indian Ocean

Territory of Diego Garcia, removing several other countries from tidal

wave risk.

A few thousand people were evacuated to higher ground from parts of

India's Andaman and Nicobar islands.

"There could be high waves of 1.5 metres at Port Blair and 3.9 metres at

Campbell Bay," said Prabhakar Rao, the official in charge of the disaster control room at Port Blair,

the main town on the islands.

Small waves about half-a-metre high and within normal tide limits had already washed into the

Campbell Bay area on the Great Nicobar island, the official said.

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At least three tsunamis of up to 80cm hit Indonesia's coast, Indonesia's Meteorology and

Geophysics Agency said.

A small tsunami measuring 10cm also reached Thailand's Andaman Coast.

Phillip Charlesworth, head of the International Federation of Red Cross and Red Crescent Societies

delegation in the Indonesian capital, Jakarta, told Al Jazeera that the first quake lasted for about

three minutes.

"The shaking was quite violent, from conversations with our staff," he said. "There appears to be no

apparent damage. We certainly don’t know what the humanitarian impact is as yet. There are no

reports of any tsunamis coming ashore, although local authorities are taking precaution of

evacuating coastal communities."

Aftershocks

There were several strong aftershocks, including one at a 8.2 magnitude and the depth of 10km.

"The aftershock continued for four minutes, and it was strong," an AFP

news agency correspondent in Banda Aceh, the provincial capital, said.

"People are panicking and running outside their home and from

buildings."

Al Jazeera's Aela Callan said the tremors were also felt in Bangkok,

where buildings swayed, but there were no reports of damage.

The initial quake had struck at a depth of 33km, 495km from Banda Aceh.

The tsunami watch was in effect across the whole Indian Ocean,

including Australia, Pakistan, Somalia, Madagascar, and many other

countries.

"Earthquakes of this size have the potential to generate a widespread

destructive tsunami that can affect coastlines across the entire Indian

Ocean basin," the US Pacific Tsunami Warning Center said.

People in Banda Aceh jumped into cars and the backs of motorcycles,

clogging streets as they fled to high ground.

Al Jazeera's Syarina Hasibuan in Jakarta said people panicked across the island of

Sumatra, running out of buildings and gathering in the streets.

TSUNAMI WATCH

Issued for:

Indonesia, India, Sri

Lanka, Australia,

Myanmar, Thailand,

Maldives, British Indian

Ocean territories,

Malaysia, Mauritius,

Reunion, Seychelles,

Pakistan, Somalia,

Oman, Madagascar, Iran,

UAE, Yemen, Comoros,

Bangladesh, Tanzania,

Mozambique, Kenya,

Crozet Islands, Kerguelen

Islands, South Africa,

Singapore

"The earthquake was felt all the way to Padang, which is west Sumatra, and people ran out of

buildings and there is really a lot of panic there."

People on Twitter said tremors were felt in Singapore, Thailand, Malaysia and India. High-rise

apartments and offices on Malaysia's west coast shook for at least a minute.

In Sri Lanka, residents on the coast were ordered to move inland to avoid being hit by any large

waves.

A government statement said waves could hit the island's eastern port district of Trincomalee by

about 10:40 GMT.

"There is a strong possibility of a tsunami hitting the island after the earthquake in Indonesia,"

meteorological department deputy director M D Dayananda said.

He said the quake in Indonesia was felt in Sri Lanka, which is 1,340km northwest from the location

of the quake.

Residents fleeing

People near the coast in six Thai provinces were ordered to move to higher places and stay as far

away as possible from the sea. The Phuket airport, right on the coastline, was closed.

 

Al Jazeera's Kevin Corriveau comments

on the tsunami alert

Al Jazeera's Callan said phone lines were jammed as people were checking on their loved ones right

after the tsunami alert was issued.

She said warning signals had been heard in southern provinces.

"Thailand is quite prepared for this. They hold drills regularly to be able to get tourists and residents

to evacuate to higher areas."

Indonesia straddles a series of fault lines that makes the vast island nation prone to volcanic and

seismic activity.

A 9.1-magnitude quake off the country on December 26, 2004, triggered a tsunami in the Indian

Ocean that killed 230,000 people, nearly three quarter of them in Aceh.

Al Jazeera's meteorologist Kevin Corriveau explained the difference between Wednesday's quake

and that of 2004: "They were the same depth but the 2004 quake was a subduction earthquake -

meaning one plate went underneath the other plate - which then pushed a lot of the water up and out

from the epicentre," he said.

"This [in Aceh] is a horizontal plate. The difference is that the two plates are slipping side by side,

and not as much water is going to be displaced.

"Now that we are processing the data we know that it is a different kind of plate slippage, which is a

little less damaging hopefully than the previous one."

11 Facts About the 2004 Indian Ocean Tsunami

1. The December 26, 2004 Indian Ocean tsunami was caused by an earthquake that is

thought to have had the energy of 23,000 Hiroshima-type atomic bombs.

 

2. The epicenter of the 9.0 magnitude quake was under the Indian Ocean near the west

coast of the Indonesian island of Sumatra.

 

3. The violent movement of sections of the Earth’s crusts known as tectonic plates

displaced an enormous amount of water, sending powerful shock waves in every

direction.

 

4. The tectonic plates in this area had been pushing against each other, building pressure

for thousands of years – they continue to do so and will likely cause underwater

earthquakes and tsunamis in the future.

 

5. The shifting of the earth’s plates in the Indian Ocean on Dec. 26, 2004 caused a rupture

more than 600 miles long, displacing the seafloor above the rupture by perhaps 10

yards horizontally and several yards vertically. As a result, trillions of tons of rock were

moved along hundreds of miles and caused the planet to shudder with the largest

magnitude earthquake in 40 years.

 

6. Within hours of the earthquake, killer waves radiating from the epicenter slammed into

the coastline of 11 Indian Ocean countries, damaging countries from east Africa to

Thailand.

 

7. A tsunami is a series of waves, and the first wave may not be the most dangerous. A

tsunami “wave train” may come as surges five minutes to an hour apart. The cycle may

be marked by the repeated retreat and advance of the ocean.

 

8. 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 because there were

no tsunami warning systems in the Indian Ocean to detect tsunamis or to warn the

general populace living around the ocean.

 

9. The Indian Ocean tsunami traveled as far as 3,000 miles to Africa and still arrived with

sufficient force to kill people and destroy property.

 

10.Many people in Indonesian reported that they saw animals fleeing for high ground

minutes before the tsunami arrived – very few animal bodies were found afterward.

 

11.The earthquake-induced tsunami resulted in at least 155,000 fatalities, 500,000 injuries,

and damages that exceeded $10 billion. Also, it is estimated that 5 million people lost

their homes or access to food and water.

Sources: National Geographic, National Earthquake Hazards Reduction Program, New

York Times, New Scientist, United States Geological Society

Tsunamis: the effects

IntroductionThe effects of a tsunami on a coastline can range from unnoticeable to devastating. The effects of a tsunami depend on the characteristics of the seismic event that generated the tsunami, the distance from its point of origin, its size (magnitude) and, at last, the configuration of the bathymetry (that is the depth of water in oceans) along the coast that the tsunami is approaching.Small tsunamis, non-destructive and undetectable without specialized equipment, happen almost every day as a result of minor earthquakes and other events. They are very often too far away from land or they are too small to have any effect when they hit the shore. When a small tsunami comes to the shoreline it is often seen as a strong and fast-moving tide.

Tsunamis have long periods and can overcome obstacles such as gulfs, bays and islands. These tsunamis make landfall usually in the form of suddenly decreasing and then rapidly increasing water levels (not unlike a tidal bore) a combination of several large waves or bore-type waves. Generally tsunamis arrive, not as giant breaking waves, but as a forceful rapid increase in water levels that results in violent flooding.

However, when tsunami waves become extremely large in height, they savagely attack coastlines, causing devastating property damage and loss of life. A small wave only 30 centimetres high in the deep ocean may grow into a monster wave 30m high as it sweeps over the shore. The effects can be further amplified where a bay, harbour, or lagoon funnels the waves as they move inland. Large tsunamis have been known to rise to over 100 feet!

Video: Earthquake and tsunami occurred in Japan on 11-Mar-2011DestructionThe amount of energy and water contained in a huge tsunami can cause extreme destruction when it strikes land.

The initial wave of a huge tsunami is extremely tall; however, most damage is not sustained by this wave. Most of the damage is caused by the huge mass of water behind the initial wave front, as the height of the sea keeps rising fast and floods powerfully into the coastal area. It is the power behind the waves, the endless rushing water that causes devastation and loss of life. When the giant breaking waves of a tsunami batter the shoreline, they can destroy everything in their path.

Destruction is caused by two mechanisms: the smashing force of a wall of water traveling at high speed, and the destructive power of a large volume of water draining off the land and carrying all with it, even if the wave did not look large.

Objects and buildings are destroyed by the sheer weight of the water, often reduced to skeletal foundations and exposed bedrock. Large objects such as ships and boulders can be carried several miles inland before the tsunami subsides.

Tsunami waves destroy boats, buildings, bridges, cars, trees, telephone lines, power lines - and just about anything else in their way. Once the tsunami waves have knocked down infrastructure on the shore they may continue to travel for several miles inland, sweeping away more trees, buildings, cars and other man made equipment. Small islands hit by a tsunami are left unrecognizable.

Image: Homes are destroyed by a tsunamiEspecially along a high seismic area, known as the Ring of Fire, tsunamis may have dramatic consequences as they hit less developed countries.

The buildings infrastructure in these poorer nations are not well built and cannot withstand the impact of the tsunami. Whole areas and towns are a picture of destruction as the tsunami leaves at trail devastation and misery behind it.

DeathOne of the biggest and worst effects of a tsunami is the cost to human life because unfortunately escaping a tsunami is nearly impossible. Hundreds and thousands of people are killed by tsunamis. Since 1850 alone, tsunamis have been responsible for the loss of more than 430,000 lives. There is very littlewarning before a tsunamis hits land. As the water rushes toward land, it leaves very little time to map an escape plan.

People living in coastal regions, towns and villages have no time to escape. The violent force of the tsunami results in instant death, most commonly by drowning. Buildings collapsing, electrocution, and explosions from gas, damaged tanks and floating debris are another cause of death. The tsunami of December 2004 that struck South East Asia and East Africa killed over 31,000 people in Sri Lanka only, leaving 23,000 injured.

Image: Child being carried awayDiseaseTsunami waves and the receding water are very destructive to structures in the run-up zone. The areas close to the coast are flooded with sea water, damaging the infrastructure such as sewage and fresh water supplies for drinking.

Flooding and contamination of drinking water can cause disease to spread in the tsunami hit areas. Illnesses such as malaria arise when water is stagnant and contaminated. Under these conditions it is difficult for people to stay healthy and for diseases to be treated, so infections and illnesses can spread very quickly, causing more death.

Environmental impactsTsunamis not only destroy human life, but have a devastating effect on insects, animals, plants, and natural resources. A tsunami changes the landscape. It uproots trees and plants and destroys animal habitats such as nesting sites for birds. Land animals are killed by drowning and sea animals are killed by pollution if dangerous chemicals are washed away into the sea, thus poisoning the marine life.

The impact of a tsunami on the environment relates not only to the landscape and animal life, but also to the man-made aspects of the environment. Solid waste and disaster debris are the most critical environmental problem faced by a tsunami-hit country.

Recycling and disposal of this waste in an environmentally sensitive manner where possible (crushing concrete, bricks, etc. to produce aggregate for rebuilding and road reconstruction) are critical.

Image: Tsunami environmental impact

Combined with the issue of waste is that of hazardous materials and toxic substances that can be inadvertently mixed up with ordinary debris. These include asbestos, oil fuel, and other industrial raw materials and chemicals. Rapid clean-up of affected areas can result in inappropriate disposal methods, including air burning and open dumping, leading to secondary impacts on the environment.

Contamination of soil and water is the second key environmental impact of a tsunami. Salination of water bodies such as rivers, wells, inland lakes, and groundwater aquifers can occur in most cases. This also affects the soil fertility of agricultural lands, due to salination and debris contamination, which will affect yields in the medium and long term. Sewage, septic tanks and toilets are damaged contaminating the water supply.

Last but not least, there may be radiation resulting from damage to nuclear plants, as it happened in Japan in March 2011. Since radiation exists for a long time, it has the capacity to inflict damage upon anything exposed to it. Radiation is most dangerous to animals and humans causing destruction as molecules loose their electrons. The damage caused by radiation to the DNA structure determines birth defects, cancers even death.

CostMassive costs hit communities and nations when a tsunami happens. Victims and survivors of the tsunami need immediate help from rescue teams.

Governments around the world may help with the cost of bringing aid to devastated areas. National institutions, the United Nations, other international organizations, community groups and NGOs , and a variety of other entities come together to provide different kinds of aid and services. There might also be appeals and donations from people who have seen pictures of the area in the media.

Reconstruction and clean up after a tsunami is a huge cost problem. Infrastructure must be replaced, unsafe buildings demolished and rubbish cleared. Loss of income in the local economy and future losses from the destruction of infrastructure will be a problem for some time to come.

The total financial cost of the tsunami could be millions or even billions of dollars of damage to coastal structures and habitats. It is difficult to put an exact figure on the monetary cost but the cost may represent an important share of a nation’s GDP.

Image: Rescue teams carry away a man injured by a tsunamiPsychological effectsVictims of tsunami events often suffer psychological problems which can last for days, years or an entire lifetime. Survivors of the Sri Lankan tsunami of December 2004 were found to have PTSD (post traumatic stress disorder) when examined by the World Health Organization (WHO): 14% to 39% of these were children, 40% of adolescents and 20% of mothers of these adolescents were found to have PTSD 4 months after the tsunami.

These people were suffering from grief and depression as their homes, businesses and loved ones were taken from them. Many still had PTSD. Periliya Village counts 2,000 dead and 400 families became homeless. These people were found to still have psychological problems 2 years after the tsunami.