The Earth is in constant motion and change, the gradual accumulation of enormous energy, in some of the vulnerable areas of the earth's crust, caused by rock formations sudden rupture, or caused by the original fault dislocation, thus forming the earthquake.
The earth is in constant motion and change, gradually accumulated huge amounts of energy in the earth's crust, certain vulnerable areas, resulting in a sudden rupture of rocks, or cause the original fault dislocation, resulting in the earthquake.