Tsunami is a series of waves generated in a body of water by an impulsive disturbance, landslides, earthquakes, volcanic eruptions and explosions.
The word Tsunami, ‘tsu’ means harbour and ‘nami’ means wave. Tsunami can be generated when the sea floor abruptly deforms and vertically displaces the overlying water. Tectonic earthquakes are a particular kind of earthquake that is associated with the earth’s crust deformation. When these earthquakes occur beneath the sea, the water above the deformed area is displaced from its equilibrium point.
Waves are formed as the displaced water mass, which acts under the influence of gravity, attempt to regain its equilibrium position. When large areas of the sea floor elevate, a tsunami can be created. On 26th December, 2004, an earthquake of 9.0 magnitude look place having epicenter at the western coast of northern Sumatra.
About hundred thousand people were killed by tsunamis of heights of up to 15 m, which flooded coastlines between 15 minutes and 10 hours after the quake, causing the deadliest tsunami in recorded history one of the deadliest natural disasters, which affected the economy and life of the people of Indonesia, Thailand and Sri Lanka and Andaman and Nicobar Island in India, in the same way. Katrina affected the entire state of Mississippi and Louisiana, Alabama and Florida on 25th August, 2005 in USA gulf area.
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The death toll from the earthquake, the tsunami and the resultant floods were reported to be more than 150,000, with tens of thousands of people reported missing and about a million left homeless.
Chuwar Island in the Nicobar has lost 2/3 of its population of 1,500. One fifth of the population of the Nicobar Island is said to be dead, injured or missing.