Earthquake

An earthquake 

is a vibration or shock that occurs in the earth's surface caused by the release of energy from the sudden that creates seismic waves.

Most earthquake caused from the release of energy generated by the pressure caused by moving plates. The longer the pressure was becoming enlarged and eventually reach the state where the pressure is no longer tolerated by outskirts of the slab. That,s when earthquakes will occur.

Earthquake usually occur at the border of the plates. The most severe earthquake usually occur at plate boundaries compressional and translational. Earthquake focus in most likely occurred because the material is squeezed into the lithosphere layer undergoes a phase transition at depth of more than 600 kilometers.

Several other earthquake can also occur due to movement of magma inside the volcano. Earthquakes like it could be a symptom of impending volcanic eruption. Several earthquakes (but rarely) occur also because accumulated a huge mass of water behind the dam, like the Caribbean Dam in Zambia, Africa. Some (rare too) can also occur due to fluid injection or akstraksi from or to earth ( example in some geothermal power plants and in the Rocky Mountain Arsenal. Lastly, earthquake can also occur from blasting explosives. This can make scientists monitor secret nuclear weapons tests conducted by the government. Earthquakes are caused by humans is also called induced seismic.