The 2004 Tsunami Earthquake was recorded at an initial magnitude of 9, but was later revised in the next year to be actually 9.3. It happened on 00:58:53 UTC on December 26, 2004

The central earthquake’s centre was located at 3.316°N 95.854°E, which is north of Simeulue Island, approximately 160 kilometres away. The earthquake occurred 30km below the surface of the ocean.

The Indian Ocean Earthquake was caused by 1600 km of faultline sliding 15m across the area in which the Indian Plate is subducting under the Burma Plate. Not all of hit happened all at once, but rather in the space of several minutes, in two stages. The earthquake caused a massive rupture 400 km long and 100 km wide, 30 km below the bottom of the sea. The rupture moved with a velocity of about 10000 km per hour, starting at the border of Aceh, moving in a NW direction, in a matter of about 1 minute and 40 seconds. After a pause of 100 seconds the rupture moved north towards two islands, the Nicobar and the Andaman. This rupture moved more slowly this time, at speed of 7600 km per hour. It kept going for 5 minutes before the fault changed to strike-slip from subduction, where the plates slide over each other. The rate at which water was displaced was dampened by this.

Not only did the plates move along each other, but the bottom of the sea also rose several metres, displacing extremely large amounts of water and causing devastating tsunamis. The tsunamis were not created from a single point, but rather they were originated from the 1600 faultline. The waves were felt from many far places because of this. The raise in sea bed increased the global sea level by a tenth of a millimeter.

The Tsunami – What happened, the timing and what areas were effected

This tsunami behaved very much like other tsunamis. It, when in deep water travelled at a quite fast velocity of 1000km per hour, but slowed down to 10km per hour when in shallow water, creating extremely large destructive waves. Some of these waves reached heights of 30m when travelling inland.

2 hours after the earthquake, radar satellites had picked up 60m bumps in deep water, but this data was not enough to issue a warning.

The energy in the tsunami was said to have been much more than the total amount of bombs’ energy in the Second World War, with the atomic bombs included. Some waves reached up to 2km inland.

The strongest force was found in an east-west vector due to the north-south direction of the 1600km rupture that caused the earthquake.

Even though the Indian state of Kerala was protected by another land-mass, it was hit nevertheless, as the wave diffracted around the obstacle.

The waves hit different places in different times, because of the distances involved. Places like Somalia were hit very quickly, whereas other coasts, like the eastern side of India and Sri-Lanka were hit 90 minutes after the quake. The island of Sumatra was also hit around this time.

The tsunami also reached Struisbaai in South America, where it took 16 hours to reach. Partial amounts of the tsunami also leaked into the Pacific Ocean, where it was north and South American sensors picked it up. It was also detected by sensors in Japan’s Showa base in Antarctica.

The tsunami was not a single wave. The wave goes through rise and retreat cycles, with 30 minutes between the peaks of each wave. The highest wave was the third wave.

“Sunday 26 December 2004 (timings given for Khao Lak, Baan Nam Khem village)

07.58 Earthquake off west coast of Sumatra measured over 9 on the Richter scale

09.35 Sea receded to 100 metres from the Andaman coast for about 5 minutes
09.38 Large wave strikes, 2-3 metres high
09.43 First tsunami strikes – 6-7 metres high
10.03 Second tsunami strikes – 10 metres high
10.20 Third tsunami strikes, 5 metres high: causes hour long inundation
12.00 Sea level returns to normal “

Source: Department for Disaster Prevention and Mitigation, Ministry of Interior, Thailand

Section 2

General Causes

The general causes of the 2004 Indian Ocean Boxing Day Tsunami are as follows:

The earthquake, of magnitude of about 9.1 to 9.3 occurred.

This lasted for about 8 minutes

When the earthquake happened the sea floor raised a couple of metres which in turn displaced around 30km3 of water.

However the tsunami was originally harmless in deep water but soon became dangerous as it made its way into shallower water

When it went into shallower water all of the displaced water had a smaller area to move in which caused the tsunami to become a massive wall of water moving towards land sometimes 30m high

This is what caused the seismic wave event of 2004

Specific Causes

The specific causes of the seismic wave event of 2004 are as follows:

The Indian plate subducted beneath the Burma plate

The sea floor was raised during this event

The capacity of the Indian Ocean was reduced by the elevation of the sea floor.

Processes

The Indian plate went under the Burma plate

This caused an earthquake measuring 9.1 to 9.3 on the Richter scale.

The sea floor was raised several metres and displaced around 30km3 of water

This caused the tsunami

The tsunami effected many places

Some of them were Thailand. Sri Lanka and Sumatra

Description of the Impact

The United Nations has compiled an analysis that states that a total of 229866 people were lost, with 186983 dead, and another 42883 missing. In Myanmar, only 61 people were reported to be dead, but most people think that 400 to 600 people died.

There were many deaths and devastating damage even in a place as far as Africa, with the most distant death being as far as 8000km away from the epicentre.

Because the areas affected had high populations of children, and that children were more susceptible to the forces of the tsunami, it was reported by relief agencies that one third of all the casualties were children. It was also reported by Oxfam that 4 times more women than men died, due to the fact that women were waiting on the coast for their husbands who were fishermen, and caring for children at home. 9000 tourists that were visiting the affected areas at the time were also killed, Sweden being the most affected country.

Many homes and buildings were destroyed in the devastating waves, carrying much human-made material out to sea, in many pieces.

Economic Costs of the 2004 Tsunami

One of the main effects of the Tsunami, in economic terms, is the common slump in the tourist industry that most countries hit by the devastating wave experienced. Many of these places, like Phuket and the Indonesian island of Nias, which are considered popular tourist destinations, experienced lower numbers of visitors. Many countries tried to get tourists to return by pointing out that most facilities were not damaged, yet some resorts that were completely unaffected were still hit with cancellations, due to psychological reasons.

There were also many other different industries that were affected by the event, in particular the fishing industry and the insurance industry. Many countries reported that they had lost up to 3 quarters of their fishing boats. Many jobs and income earners were lost. The insurance industry also is said to have lost 10 billion dollars in damages.

Some economists however, say that this will not affect the Asian economy significantly, by stating that the fishing industry and others affected are only a small part of the total GDP. Others, however, state that Infrastructural damage is a insignificant factor. Due to the salty water, some farming areas and water supplies may be unsuitable for use for a long time.

In the Malacca straits, many buoys and old shipwrecks were displaced, meaning that shipping would be affected. The recreation of the navigational charts would take much time and money.

Social, Environmental and Other Impacts

Many children and adults experienced psychological trauma due to the disaster, with many children being left quite vulnerable. Some experts also stated that there were some long term effects associated with the 2004, with health professionals stating that there were many victims that suffered physiological trauma as a result. The WHO has stated that the affected countries would have to wrestle with much mental health issues caused by the Tsunami.

Many environmental entities had been affected by the 2004 Tsunami, like multiple ecosystems, coral reefs, mangroves, forests, wetlands, vegetations, sand dunes, rock formations, and biodiversity. The destructions of sewage systems and the spread of chemical and industrial waste also put the environment at risk. The main effect, according to specialists is the contamination of water supplies and the sterilisation of soil due to the salty waters of the sea.

There were other effects as well, particularly to religious cultures, such as the Muslim communities that required family members to bury their dead. However, often, there was no body do such a thing. Some also saw this as a punishment for their sins by their god, Allah.

Section 4

Immediate Local Response

Little was done to warm people about the incoming tsunami. Since there was no early warning system in place many people in Thailand and Sumatra were unaware of the event. This caused many people to die because the strongest and most direct part of the wave reached their shores. The tsunami started in deep water so until it came into shallower water there was no sight of it.

Many innocent lives were lost because of the lack of knowledge about how tsunamis happen. At first the water was drawn out revealing the sea bed. This caused many people to come have a look at this strange event. However, in Thailand a ten year old girl who had studied tsunamis at her school recognised the signs of a tsunami and managed to evacuate the whole beach to safety.

International Response

There was a lot of aid from countries around the world. The aid came in many forms with some of it being food and other parts of it being shelter. Although some of the money donated was put into making an early warning system for the effected countries. This will help prevent any future disasters which may happen. Aid also went to the building of medical facilities in order to prevent the spread of diseases.

What could be done in the future to prevent and mitigate this disaster.

It is well known that this sort of earthquake is inevitable to repeat itself. The reason that the 2004 Tsunami caused such a disaster is because of the absence of tsunami detectors in the Indian Ocean, and as such the wave completely surprised the victims, leaving them defenceless and unprepared. If there was warning system, and areas were affected or proofed, then less life would have been lost.

Many actions are already being taken to mitigate a future disaster. For example, some of the money that is going into the affected countries is going toward a future warning system, named Project DART, in the Indian Ocean. Some have gone further to suggest a system that connects the entire world’s warning systems together.

Thailand has also stated some lessons to be learnt from this Tsunami, such as ways that new buildings should be built to allow more buildings to survive in such case of a disaster, like holes in walls to reduce the force, and factoring in the erosion of incoming waves. It also stated that a lack of historical records of such a disaster should not rule out the possibility of one happening, if the governing factors do exist.

The places that were affected will rebuild all their buildings to be more resistant to water damage. These areas will also probably implement an effective warning system that will allow citizens to prepare and evacuate in the short hours before a tsunami strikes. Barriers could also be built, in order to lessen damage.

There also were other human factors that made the Tsunami more devastating. Many countries across Asia have chosen to destroy natural coral reefs in the sea, in order to replace them with more economical choices, like shrimp farms. Many coral reefs were also exploded with dynamite in order to make shipping easier, which is a large part of the South Asian economy. Some occupants on the Surin Island were saved by the coral reef that was protecting their island. The removal of mangrove trees and coastal sand dunes that lined the coast also magnified the damage, as it is said that these could have reduced the force of the wave.

Section 6 – Bibliography

“http://en.wikipedia.org/wiki/2004_Indian_Ocean_Earthquake”, Retrieved on 10^th of May, 2009, Published by Wikipedia, part of the Wikimedia organisation.

“www.Tsunami2004.net” , Retried on 10^th of May 2009, Published by “tsunami2004.net’.

“http://www.un.or.th/tsunamiinthailand/TheRoleandsupportofUN.html”, Retrieved on 13^th of May, 2009, Published by UN Thailand.

“http://newton.uor.edu/Departments&Programs/AsianStudiesDept/tsunami.html”, “A dictionary of resources” Retrieved on the 12^th of May, Published by Robert Y. Eng.

“http://www.library.hbs.edu/tsunami/index.html”, Retrieved on the 13^th of May, 2009, Published by “Havard Business School”.

“http://www.csa.com/discoveryguides/tsunami/overview.php?SID=2oh2qot0ffang7bnbcbjm9ghn7”, Retrieved on 13^th of May, 2009, Published by ProQuest, and the CSA.

“http://www.who.int/bulletin/volumes/83/6/infocus0605/en/index.html”, “Tsunami Wreaks Mental Havoc, Retrieved on the 14^th of May, Published by the World Health Organisation.

Images were retrieved from Google images, or the above sites. Copyrights of such images belong to their respective owners.