An earthquake is a very dreadful natural calamity. When the surface of the earth trembles, we call it an earthquake. It is caused due to the relative movement of seismological plates within the earth. It releases a lot of energy.
An instrument called seismograph is used to measure the force of an earthquake. The point where an earthquake breaks out is called the epi-centre of the earthquake.
If an earthquake is mild, it does not do much harm. But if it is violent, it can be very dangerous to life and property. If the earth shakes for two or three minutes violently, brick houses fall down and the inmates are buried alive. It is difficult for men to remain standing. Due to severe shocks, trees and towers are uprooted, and the earth can become uneven. Sometimes, the water of a river or ocean is dried up and land appears there. An earthquake may cause a tsunami too claiming thousands of lives. Crops are destroyed. As a result a famine may breakout.
The major earthquake-prone countries of the world are Japan, India, China and Russia. Thousands of people have lost their lives and many more have been rendered homeless in different earthquakes which have occurred now and then. An earthquake is a terrible thing, but is beyond human control.