The word “tsunami” comes from the Japanese tsu (harbor) and nami (wave). This name is very appropriate, considering about 80 percent of all tsunamis occur in the Pacific Ocean and Japan .  Some tsunami’s come from as far away as South America . Tsunamis are often incorrectly called tidal waves, but tides have nothing to do with them (though the damage may be worse if a tsunami hits at high tide). 

Diagram illustrating the difference between wind-generated waves and tsunamis.

A tsunami is a wave train, or series of waves, formed in a body of water by an impulsive disturbance that vertically displaces the water column.  Earthquakes, landslides, volcanic eruptions, explosions, and even the impact of meteorites, can generate tsunamis.  Tsunamis can attack coastlines, causing devastating property damage and loss of life.