Earthquake
Tuesday, July 27th, 2010 Earthquakes are caused by the sudden breaking of ground shaking and the earth’s rock cover most of the transfer. Earthquakes are among the most powerful events on earth, and their results can be terrifying. A severe earthquake may release energy 10,000 times as great as that of the first atomic bomb. Rock movements during an earthquake can make rivers change their course. Earthquakes can trigger landslides that cause great damage and loss of life. Large earthquakes beneath the ocean can create a series of huge, destructive waves called tsunamis (pronounced tsoo NAH meez) that flood coasts for many miles.
Earthquake forces, depending on how much rock breaks and how far changes.Powerful earthquakes can shake firm ground violently for great distances. During minor earthquakes, the vibration may be no greater than the vibration caused by a passing truck.
On average, a powerful earthquake occurs less than once every two years. At least 40 moderate earthquakes cause damage somewhere in the world each year. About 40,000 to 50,000 small earthquakes - large enough to feel, but without prejudice to - occur each year.