By IANS,
Washington: The devastating earthquake that shook Japan was caused by movement of massive tectonic plates that thrust one below the other and forced the seabed and ocean upwards, triggering a giant tsunami.
“Plates aren’t constantly moving at a smooth rate… The stress builds up over time — over years, decades and centuries, and then at some point it overcomes the lock between two parts of the crust. When that happens, you have an earthquake,” pbs.org quoted American geophysicist John Bellini as saying.
The geophysicist said that Japan was one of the most seismically active areas in the world.
The country is located in the “Ring of Fire”, which is essentially an arc that stretches along the basin of the Pacific Ocean.
The earthquake Friday measured 8.9 on the Richter scale and the tsunami slammed the northeastern coast, washing away thousands of cars and homes. About 1,000 people have died and a nuclear meltdown is feared at a nuclear power plant.
Japan is either on or close to the boundary of four tectonic plates: the Pacific, North American, Eurasian which are primary plates, and Philippines Sea plate, which is one of the secondary plates.
The plates are on the move and when they hit each other, it builds pressure. Then pressure releases, causing earthquakes and the rising seabed triggers tsunami, the media report said.
The Japan earthquake is estimated to have generated energy that was roughly equivalent to the energy the US consumes in a year, seismologist David Wald said.