Of course, earthquakes are one of the most terrible natural phenomena. They do a terrible disaster. Fluctuations in the earth's crust can cause damage, fire, flood, loss of life.
The study of earthquakes has shown that they arise from rupture and very rapid movement of large masses of rock or tectonic plates. Their shift and causes sharp fluctuations in the earth's crust, which are felt on the surface. Scientists found that the earth's crust consists of about 20 large and small tectonic plates. They have a thickness of from 60 to 100 kilometers.
Reasons that cause their movement, a lot. Wandering tectonic plates, falling, rising, floating on the surface of the magma. In those places where they are in contact with each other, and occur most often earthquakes.
In the bowels of the planet accumulates a large amount of heat. Outside the Earth, giving warmth in world space, is cooled, and its surface is reduced. As a result of various areas of the earth's surface experience different pressures. Perhaps this drives them.
On the earth's vibrations affect the force of gravity. Our planet consists of substances of different specific gravity. Lighter rocks tend to rise and more severe - down.
Their movement is affected by the gravitational forces of the moon and Sun.
Changing the speed of rotation of the Earth also causes deformation of the earth's crust.