Explain, in brief, the cause of an earthquake.


Earthquakes are caused by disturbances deep down inside the uppermost layer of the earth. The outermost layer of the earth is not in a ‘single piece’; it is broken into a number of plates, known as tectonic plates. These plates are moving around very slowly- just a few millimetres every year. The movements of these plates cause changes on the surface of the earth which may cause an earthquake.