》The sudden tremors or shaking of the earth's crust is called an earthquake. When a part of the earth's surface moves backward and forward or up and down, the earth's surface ' quakes' and these are called the earthquakes.
》The earth's crust is made up of different parts of various sizes. They are called plates. Most of the earthquakes in the world are caused by the movements of the plates (Tectonism).
》'Seismology' the special branch of geology, It deals with the study of earthquake.
》'Richter scale' and 'Mercalli scale' are the instruments to measure the magnitude and the intensity of an earthquakes respectively.
