The 9.2一magnitude(震级)earthquake which caused the tsunami in
the Indian Ocean on Boxing Day last year occurred at 7:58 a.m.,95 miles off the west coast of Aceh, Indonesia.
Eighteen minutes later.10-metre high waves crashed the ashore along a 500——mile-long stretch of Aceh.
Two hours later the tsunami hit Thailand and Malaysia and then Burma, Bangladesh, India,the Maldives,Sri Lanka,Kenya and Somalia.The final death toll is thought to be about 280,000,with tens of thousands more listed as missing.More than l.8 million people lost their homes.
●What Is Tsunami?
A tsunami is a chain of fast moving waves caused by a sudden strong quake in the ocean.They can be caused by earthquakes,volcanic eruptions(爆发),or even the collision of meteorites(陨星).Tsunamis are also incorrectly known as tidal waves,but unlike tidal waves they are not caused by changes in the tides.
They are also most common around the edge of the Pacific,where more than half of the world’s volcanoes are found.These fast moving waves can attack coastlines,often with little or no warning.Rocks weighing as much as 20 metric tonnes have been pulled from sea walls and carried l 80m inland.
●Wave Power
Atsunami can have a wavelength in excess of(超过)1 00km and there may be an hour between them.They travel at great speeds across an ocean with hardly any energy losses and are barely noticeable out at sea.
Over the deep Pacific Ocean,a tsunami travels at about 800kph.If an earthquake happened in Los Angeles.a tsunami could hit Tokyo quicker than you could fly between the cities by jet.
●Strange Animal Behaviors
Ten days before giant waves slammed into Sri Lanka and India coastlines,wild and domestic(家养的) animals seemed to know what was about to happen and fled(逃跑)to safety.
Elephants screamed and ran for higher ground.
Dogs refused to go outdoors.
Zoo animals rushed into their shelters and could not be enticed(引诱)to come back out.