The interior of the earth becoming cooler day by day, which is sure to cause some shrinkage in the earth crust. The stink age is responsible for the stress to be developed withing the earth crust. These stresses, when greater in magnitude exert so much pressure that the layers of the earths crust are fold due to compressive stresses and afterwards when the stresses are released, fractures are formed. If the stresses still continue, the blocks move up and down along the fault plane depending upon the direction of stresses and their intensity. Such a fracture, along which a movement has taken place, is called a fault.