Tsunami is a Japanese name for 'harbour waves' generally called tidal waves but actually tsunami has nothing to do with tides. Tsunami is generated when ocean floods shift vertically, usually due to an earthquake. When a shift in the ocean floor displaces the water above, the water body travels as a huge wave to regain equilibrium. Actually tsunami is generated as a result of a sudden rise or fall of section on the earth's crust under the ocean.
A seismic disturbance can displace the water column creating a rise or fall in the level of the ocean above. This rise or fall in sea level is the initial formation of tsunami wave.
Unlike surface waves that affect only a shallow amount of water, a tsunami stretches all the way to the sea floor, as rises to the land, so does the wave. Arriving at shore, such waves can grow suddenly by dozens of feet. The satellite imaging did not provide a depth for the waves that hit ashore. In deep water, a tsunami can travel at 700 km per hour.
But in shallow water near coast, it get slower and water mass rises up to 50 meters. A tsunami is very much destructive. It can strip coasts of land, uproot trees, wipe out towns. The records of tsunami deaths or disaster are generally not available as they are commonly fixed with earthquake deaths.
In the year 1755 on 1st Nov. a colossal earthquake destroyed Libson, Portugal and rocked much of Europe, a tsunami followed, killing more than 60,000. August 27,1883 was another day of disaster. The eruptions from Krakatoa volcano fuelled a tsunami that drowned 36,000 in western Java and southern Sumatra. On 23rd August, 1976 a tsunami in southern west Philippines killed 8,000.
In another tsunami disaster waves as high as 100 feet, spawned by an earthquake, swept the east coast of Japan in which 27,000 people died.
In the latest tsunami on 26th December, 2004 in Indian Ocean caused because of an undersea disturbance which was the result of an 8.9 magnitude earthquake, just off the northern tip of Indonesia's Sumatra Islands. This created a havoc in Indonesia, Hong Kong, Sri Lanka and India. It is estimated that more than 1 million people lost their lives and more than this are missing and the total loss must be of hundred of crores.
Tsunami affected India's southern part. The most affected areas were Tamilnadu and Andaman & Nicobar Islands. Joggers on the Marina Beach in Chennai and fishermen all over the Tamil Nadu coast got a jolt of their lives as these deadly waves lashed these coastal areas within seconds and washed away over 25,000 people, leaving equal number untraceable.
Tsunami struck India for the first time in the recorded history. The country 3 still coming to grips with nature and scale of disaster. The worst affected . ere the 45,000 people of Car Nicobar and Greater Nicobar where a earthquake of 7.5 magnitude hit the area in the morning.
In Indonesia, Sri Lanka and Hongkong thousands of people lost their lives and up to five million people have been displaced by the divesting tsunami that pummeled large areas of Asia. Three millions out of these affected are in Indonesia alone and another one million in Sri Lanka. The rest were spread between India, Maldives and other nations hit by tsunami waves.
But the most surprising is that wildlife in Sri Lanka's biggest national park survived the December's tsunami, but it was probably keen senses and the lay of the land rather than any mysterious instinct danger enabled animals to scamper to safety. It was a acute natural senses such as hearing that helped animal’s times to flee. It is an ancient belief that animals have a sixth sense for danger and this sense must have a med animals of tsunami's approach.
Geography and planning saved Maldives from these deadly tsunami. While standing on the highest point rock of the Maldives and looking down the Indian Ocean less than 3 meters below, it is easy to see why this nation of low-lying atolls fears rising sea-levels will one day wipe it off the map. When a giant tsunami crushed fishing villages and tourist resorts across Asia became a reality the day after Christmas.
It was combination of geography and planning the death toll in the Maldives stands at just 80 in a disaster that claimed more than 1,50,00 from Indonesia. Many the Maldives 1,200 tiny palm-fringed coral islands 800 km off the toe India were swamped by these tsunami waves about a meter high.