An earthquake is a sudden and abrupt movement in the earth crust. It usually results from movement along plate margins within the lithospheric slabs. If the epicenter of such earthquake is in the ocean, large volume of water can be displaced which can lead to the formation of a high velocity tsunami. After an earthquake, a passive quaking lead to an aftershock. Sometimes, the strength of a rock can be reduced as a result of earthquake, this leads to the liquefaction shaking after an earthquake.
These and many more are the effects of earthquakes.
