Earth quack is the vibration caused by the movement which is collection and the sudden depletion of the energy of strain in broken is known as earth quack.
 Natural events such as volcanic eruptions and meteor impacts can cause earthquakes, but the majority of naturally-occurring earthquakes are triggered by movement of the earth's plates.
The National Earthquake Information Center (NEIC) records an average of 20,000 earthquakes every year (about 50 a day) around the world. There are, however, millions of earthquakes estimated to occur every year that are too weak to be recorded.... :)