介绍:
Tsunami-the giant wave.（p64）
Natural disasters such as volcanic eruptions，fires,floods and avalanches happen every year,somewhere in the world .But there is another ,and perhaps even more dangerous ,natural disaster,which we do not hear about very often.A tsunami is huge wave that can cause terrible damage and destruction.
Tsunami is a Japanese word that means ‘harbour wave’.But why do tsunamis happens?Tsunamis are usually caused by earthquakes at the bottom of the sea.At first, the wave in the sea is quite small,but it moves very quickly. When the wave gets close to the coast, the ocean floor makes it grow enormously.By the time it reaches the coast it has become huge.Some tsunamis can be 30 metres high.
These giant waves can hit Japan,Indonesia,Central America and South America.In 1960, there was a big tsunami in the Pacific Ocean.Tsunamis do not happen very often ,but Hawaii now has a ‘tsunami-watch’ station that watches for the next one to come.The station was opened to warn people and give them time to protect themselves against the killer waves.
On December 26th,2004,there was an earthquake at the bottom of the Indian Ocean that measured 8.5 on the Richter Scale.The earthquake started a giant wave that hit the coast of Indonesia,Thailand,Sri Lanka,the Maldives,India,Bangladesh and Myanmar .The wave travelled at around 800 kilometres per hour over the 4,500 kilometre-wide Indian Ocean.It hit the east coast of Africa seven hours after the earthquake.Over 300,000 people were killed.Whole towns were destroyed ,and thousands of people lost their homes.Other countries offered $7 billion to help.It was the world’s biggest earthquake for forty years.There was no warning station in the Indian Ocean.
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