<p>An earthquake is movement of earth crust. </p><p>The surface beneath the earth is formed of plates.</p><p>When these plates collide with each other, an earthquake is emerged.</p><p>The strength or magnitude of earthquake is measured using Richter Scale. Which is measured from 1 to 9. </p><p> The magnitude of earthquake differs form small to high.</p><p>A magnitude below 5 scale is considered as small and mostly is not harmful.</p><p> However, a magnitude above 5 or above is considered as dangerous. As it may case damage to buildings and life.</p>