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Giant waves caused by earthquakes or volcanic eruptions under the sea are called Tsunamis. The term ‘Tsunami’ is derived from the Japanese language which means harbor wave. As these waves travel inland, the depth of the ocean keeps decreasing, helping them build up their height. They travel as fast as jet planes over deep waters, forcing their way through any obstacle. The sheer weight of the water destroys buildings. Ships and boulders get carried several miles inland because of the powerful waves. 

Roman historian Ammianus described Tsunami as – an earthquake resulting in sudden retreat of the sea, followed by an enormous wave. So far, numerous Tsunamis have occurred in Japan. The Tsunami which occurred in the Indian Ocean, in the year 2004, is considered as one of the most devastating natural disasters in modern times. The death toll was 2,30,000 people.

Tsunamis possess immense energy allowing them to travel great trans-oceanic distances. A Tsunami is capable of causing damage over thousands of kilometers from its origin. Which means there will be a considerable time gap between its creation and its impact on the coast. 

Signs of Tsunami

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Nature gives several warning signals before a Tsunami. We can experience earthquakes, the sea might look as if it’s boiling just before a ‘Tsunami’.  The water can be hot and also smell of rotten eggs because of the presence of hydrogen sulfide or of petrol or oil. The sea may recede to a considerable distance as well. In certain instances, as the Tsunami waves are approaching, a flash of red light may appear near the horizon, the top of the wave will glow red!

History of Tsunami

It is said that the Lisbon quake in Europe in 1755 generated a 12 meter high sea wave destroying most part of the city killing around 60,000 people. In the year 2011, Japan experienced a massive earthquake (8.9 on Richter Scale), triggering a giant Tsunami in the Pacific Ocean, killing over 15,000 people in the country.

Reducing Damage

Over the years, Tsunami-prone countries have taken measures to reduce the damage caused by the gigantic waves. For example, Japan has built ‘Tsunami walls’ which are almost 13.5 ft high in front of populated coastal areas. Several localities in the region have also built floodgates and channels to redirect water from incoming Tsunamis. 

Similarly, tree cover on the shoreline can also help in mitigating the effects of a Tsunami. For example, in the 2004 Indian Ocean Tsunami, the village of Naluvedapathy in Tamil Nadu suffered minimal damages. The waves broke upon a forest of 80,244 trees planted along the seacoasts. The trees consisted of coconuts, palms and mangroves. 

These plantations are cheaper and longer-lasting means of Tsunami mitigation compared to the method of erecting artificial barriers.

Tsunami warning system

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Tsunami warning systems help in detecting Tsunamis and warning the people before the wave reaches the coasts. Computer models help in predicting Tsunami arrival and its impact based on available information, and the shape of the seafloor and the coastal landmass. At times, animals in the region might sense danger and flee to higher ground before the water arrives.

In the year 2011, the Japanese government announced that it will be providing Tsunami forecasts, for helping people prepare better for the disaster. The Intergovernmental Oceanographic Commission, UNESCO is working on several methods to mitigate the effects of Tsunami.

World Tsunami Awareness Day

World Tsunami Awareness Day is celebrated every year on November 5th to spread awareness about the deadly natural disaster which killed over 260,000 people in the world so far.

There are around 700 million people across the globe who are living in low-lying islands and coastal areas!

Check your knowledge

Answer) Giant waves caused by earthquakes or volcanic eruptions under the sea are called Tsunamis.

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