TSUNAMI- A NEW PHENOMENON FOR INDIA
Tsunami is a new phenomenon for India. Tsunami waves travel faster in deep water, rising further as they approach shore. In open sea, Tsunami is only about a meter high. But when they reach a shoreline, they can be taller than a house and weigh millions of tones.
The bottom of the wave is slowed down by the sharp elevation of the ocean floor near the coast. But its top part keeps moving at the original speed. As a result, vast quantity of water piles up and finally crashes over the shore. Due to its amazing force, it causes massive destruction.
The first sign of an approaching Tsunami is the sea tide receding from the shore. It leaves a large part of the sea floor exposed. The ocean water then flows towards the shore faster than before. As a result high waves are formed. This phenomenon is repeated several times before the Tsunami itself hits the land. The Tsunami can travel long distance without losing the original power. Neither islands nor roofs diminish their speed or power.
Usually the waves do not dissipate until they strike a continental landmass. Some waves even travel back and forth across the ocean for over a week. Japan is one of the two Asian countries the other being Indonesia to be frequently hit by Tsunami waves. In fact, the word Tsunami is derived from the Japanese language. It is used by Japanese to describe very long, low seismic sea waves.
Tsunamis are common in the Pacific Ocean, as there is significant movement of the earth’s tectonic plates in the region.
Fortunately, Tsunami of a serious nature are known to occur only once in a decade in the region. But when they occur, they leave a trail of destruction, causing heavy damage of life and property. The major ones the Prince William Sound, Alaska in March 1964, and the one generated off the coast of Chile on 1960 caused havoc over large distance. Hundreds of people died when a huge wave traveling at a speed of 750kms per hour smashed Japan in 1960. Following it a series of quakes in Chile on the other side of the Pacific Ocean took place.
In the Indian Ocean, which was hit by a quake the Indo Australian plates is being sub ducted by the east margin of the Eurasian plate. Therefore, most tsunamis generated in this area are propagated towards the south west shores of Java and Sumatra rather than in to the Indian Ocean.