T SUNAMI

 T SUNAMI

Introduction

Tsunami (Pronounced as (Su-na-mi) is a Japanese word. In Japanese language, Tsu' means "harbour" and 'Nami' means 'wave'. Tsunami means giant sea-waves which hit the harbour and creates havoc.

How it happens

The crust of the earth isnot made of a single plate. It is made of several movable plates which are about 80 km. thick. When any two of the plates collide, liquid lava erupts through volcanoes. The earth is shaken by the impact of volcanic eruption. When earthquake measuring 6.5 or higher in Richter scale happens under the ocean bed within a depth of 50 kms, tsunami is created. Sometimes cracks appear in the ocean bed due to earthquake. One portion of the ocean bed rises while another portion sinks. With this the level of ocean water either rises up or goes down. This causes terrible tsunamis. The circular giant waves spread up to thousands of kilometers. The waves created by wind breaks down within 5 to 20 seconds, whereas the time lag between two tsunami waves ranges from 10 minutes to two hours. The space between the crusts of two ordinary waves is 100 to 200 metres whereas the same between the crusts of tsunami waves is about 500 kms. The reduction of the quantum of force is inversely proportional to the length of the tide. So in case of very long tsunami tides, the reduction of force is negligible.

Movement of tsunami

At the place of origin, the height of tsunami waves is from. 0.5 to 1 metre. They move at the speed of 500 to 1000 kms per hour. When the tide reaches the shallow coast, its speed is reduced due to friction with the sea-bed. It results in the reduction of distance between two waves. But the waves rise up to unbelievable heights. Sometimes it rises up to more than 30 metres. It floods the coastal area up to hundreds of metres. The destruction of life and property created by tsunami is beyond imagination.

2004-tsunami

On 26 December,2004, at 6.29 am (Indian time), there was an earthquake measuring 8.9 in the richter scale near the Western coast of Sumatra in the Indian ocean. Its epicentre was under the sea-bed within 3.298° latitude and 95.779° altitude. Gradually the tsunamis created by the earthquake spread towards North-east and created havoc in about 27 South-East Asian countries. The force of this violent tsunami was so great that the sumatra island has been pushed about 36 meters towards South-East.The states worst hit by this tsunami were Indonesia, Srilanka, Maldives, Bangladesh, Thiland, Malayasia and India. More than one lakh fifty thousand people perished in this tsunami. More than ten lakh people became homeless. Properties worth crores and crores of rupees were destroyed. Lakhs of livestock, wild animals and sea animals died. The wretched condition of tsunami-hit survivors is really heart-rending.

Occurrences

The tsunami is not a new phenomenon. It appears regularly. The Howaii islands has been hit by tsunami 40 times since 1819. On 26th and 27th August 1883, the tsunami created near Java, submerged the Krakatoa island without trace.

In the tsunami of 26 December, 2004, about 80,000 people of Indonesia, 30,000 people of Srilanka and 13,000 people of India died. The coast of Tamilnadu was devastated. The people of Ir.dia donated handsomely for the rehabilitation of the tsunami-hit. A lot of survivors may alo die due to diseases, mal-nutrition and lack of shelter. Those who have lost their dear ones will never be consoled. The tsunami disaster proves that man is a helpless doll in the lap of the giant nature.

Conclusion

Although it is impossible to check disasters like tsunami, earthquake and cyclone, early warning systems can be installed. The mangrove forests act as a natural wall against the tsunami and cyclone. The shortsighted developers are clearing mangrove forests to construct beach-side resorts for sheer profit. This must be stopped. No inhabitation should be allowed within five kilometers of the sea-coast. Unless we heed the warning of nature, we shall invite our own peril.

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