Most earthquakes can be explained coherent by the theory of tectonics plate . According to this theory, the outer shell of the Earth (the lithosphere) consists of some relatively stable massive huge rock, called tectonic plates. The main tectonic plates have an average thickness of about 80 km and are moved by the movement of convection in the mantle, which in turn is created by heat generated in the nucleus.
Relative movement of tectonics plate is responsible for a part of significant seismic activity worldwide. Collision between lithosphere plates, edges destruction of tectonic plates in subduction zones (convergent area) at a slip of a plate
under another plate,or expansion in the ocean divergent areas, are all mechanisms that produce significant tensions and fractures in the earth's crust. Many major earthquakes
is due to sliding along transcurrents faults .
Earthquakes generated from the active edges of tectonic plates is called earthquakes inter-plate. Strongest surface earthquakes in Chile, Peru, Eastern Caribbean, Central America, southern Mexico, California, Alaska South and Aleut Kuril Islands, Japan, Taiwan, Philippines, Indonesia, New Zealand, belt Alps - the Caucasus - the Himalayas are the type of Intra-plate earthquake. Average speed of movement of tectonic plates is 2-5 cm / year.
In addition to earthquakes generated in the active edges of tectonic plates, sometimes occur devastating earthquakes within the plate tectonics. The latter is called intra-plate earthquakes. Such earthquakes indicate that the lithosphere plates are indeformabile and inside them that can cause fractures. Examples of such earthquakes are north-east Iran, New Madrid (Missouri), Charleston (South Carolina, USA), northern China.
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