Fourth largest earthquake hit japan on march 11,2011 and make Tsunami.The earthquake centered in Tohoku region of japan with 9.0 in richter scale,that may have killed 30,000 people.More than 60 aftershocks with 6.0 magnitude have struck the region.The main quake remained more than 3.5 minutes, most of the energy was released in the first 2 minutes.
The total region centered by the quake was 155 miles (250 kilometers) long and 109 miles (175 km) wide. After the main shock many aftershocks hit with the magnitude of 6.4 or greater. The largest aftershock struck less than an hour after the main shock with the magnitude of 7.9.
According to preliminary data,the quake reputed five areas with in the region that have previously ruptured as separate earthquakes.But the true fact is that these areas linked together during the March 11 earthquake.This is the reason why the earthquake was unexpectedly large.