The earthquake, also known as earth movement or earth vibration, is the vibration caused by fast energy release from the earth crust and a natural phenomenon producing earthquake waves. The dislocation and fracture of the plate edge and interior are caused by the extrusion and collision among plates on earth, as the main reason for earthquake.
The site where the earthquake occurs first is called hypocenter, the ground right above which is called epicenter. The place with the most violent ground vibration of destructive earthquake is called the meizoseismal area, where epicenter is often located. The earthquake often causes serious casualties, fire, flood, toxic gas leak, bacteria and radioactive substance diffusion, and even tsunami, landslide, collapse, ground fracture and other secondary disasters.