Using an example, outline the effects of a tsunami and how the hazard can be managed

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Using an example, outline the effects of a tsunami and how the hazard can be managed

   Tsunami is Japanese for 'harbour wave', and is usually formed through the combination of a series of water waves, commonly known as a 'tsunami wave train', which are in turn caused by the displacement of a large body of water, e.g. an ocean. As the wave train reaches shallow depths, they tend to combine into a single large wave travelling at immense speeds (600 km/h), steepening rapidly to heights of 80 feet plus, resulting in a tsunami. A natural disaster is usually the root cause of such a displacement of water, and thus earthquakes, volcanic eruptions and underwater landslides are common causes of tsunami formation. The effects and management of tsunamis depend on several factors. The most obvious of course is the intensity of the tsunami, or more specifically the natural disaster which caused the tsunami. For example the intensity of the Indian Ocean tsunami of 2004 is categorised by the measurement of its earthquake tremor, 9.3 Mw on the Richter scale. The next factor is whether the country(s) affected have high population densities as well as the economic development of each country. A densely populated MEDC equipped to deal with such disasters tend to limit the impacts of such a deadly event however still cannot prevent high death tolls. On the other hand both densely/sparsely populated LEDCs lack the infrastructure and facilities to cope with such a disaster and as a result tend to have an extremely high number of fatalities, as recently seen in Chile, Haiti and the Indian Ocean Earthquakes tsunamis.

   On 26th of December 2004 an underwater 'megathrust' earthquake measuring 9.3 on the Richter scale (the second largest earthquake ever recorded) occurred off the northern coast of Sumatra, Indonesia. The central cause of this was due to the sudden release of pressure during the collision of the Indo-Australian plate (moving NE 6cm/year) beneath the Eurasian plate (moving SE 1cm/year). The earthquake occurred at a depth of 30km below sea level along 1200km of fault line. The resulting tremor caused the rebound of the Eurasian plate by up to 20m along the entire fault line, in turn displacing a vast amount of water. Due to the positioning of the fault, the strongest tsunamis were directed in an east-west direction meaning Sri Lanka and Indonesia, both in close proximity to the epicentre of the earthquake and directly east and west of the tremor respectively, suffered high casualties and significant damage to infrastructure. Conversely, countries to the north of the tremor with similar proximity, such as Bangladesh and Myanmar were hardly affected at all with minimal casualties and only minor damage to infrastructure.

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   Initial estimates value the total number of fatalities around 230,000 (according to the U.S. Geological Survey) however these figures rise as high as 280,000. As aforementioned, the 2 key areas which experienced the most devastating effect of the Indian ocean tsunami was Sri Lanka, but more tellingly Indonesia, which recorded almost half of the casualties. The Aceh province in north-west Sumatra (Indonesia) was said to be the most severely affected in Sumatra and contained several of the 1500+ villages and 100+ schools destroyed in Sumatra. In many coastal settlements surrounding the Indian Ocean, fishing was a major occupation as ...

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