A tsunami is a series of water waves caused by the displacement of a large volume of a body of water, usually an ocean. These waves which often affect distant shores, originate by rapid displacement of water from the lake or the sea either by seismic activity, landslides, volcanic eruptions or large meteoroid impacts.
Whatever the cause may be sea water is displaced with a violent motion and swells up, ultimately surging over land with great destructive power. The effects of a tsunami can be unnoticeable or even destructive.
Read more: Guidelines for Management of Tsunamis