Answer the following in one or two sentences:

What is an Earthquake and how it occurs?

Earthquake is caused by the sudden vibration under the earth crust. The vibration spreads outward in all the direction as waves from the source of the disturbance. The point at which the earthquake starts is called focus (hypocenter) which creates a series of waves. The epicentre is a point on earth surface which lies above the point of focus, the effect of the earthquake is mainly caused by the epicentre. An earthquake occurs due to release of energy along a fault. A fault is a sharp break in between the crustal rocks .rocks and fault to move in opposite direction.

It occurs from the focus, where the vibration starts and extends up to the Epicentre. It makes the shaking in above the crust and this makes the buildings also shake.