Competitive Exams: Earthquakes

When the earth's crust suddenly vibrates or shakes, we call it an earthquake. Earthquakes are caused by cooling and contraction of the earth's interior, by the interior getting molten due to removal of the crust's pressure as a result of erosion, or by the steam generated when the water that percolates through the crust reaches internal hot rocks resulting in volcanic activity. Earthquake vibration may be mild or strong. The minor or the less destructive earthquakes occur more frequently than the major ones. Earthquakes Belts: Earthquakes occur in almost every part of the world. They are very common in volcanic districts, and where the earth's crust is weak. The most active region is a belt surrounding the Pacific Ocean. About 70 percent of the earthquakes occur in this belt. The other important belt runs across Central Asia, the Mediterranean and the Atlantic to West Indies.