Earthquake comes under the category of natural disaster. Our earth has four layers—inner core, outer core, mantle and crust. Crust and mantle have covered the whole earth but not by its one piece of layer but having many of pieces called tectonic plates. These plates keep moving around and the edges of them are called plate boundaries. Plate boundaries contain many faults and major earthquakes occur on these faults only. When rock underground gets suddenly broken along a fault because of high pressure, earthquake is caused because that time sudden release of energy in the earth’s
crust creates seismic waves which shake the earth’s surface. Earthquake is measured by seismometers. Volcanic eruptions, landslides, explosions and rock falls, etc can also cause earth-quakes but these are generally of only local extent. Even shocks from a powerful earthquake have capacity to cause small earthquakes in distant locations if geologic conditions favour.
