A tsunami is a series of large, persistent waves caused by the sudden displacement of a body of water. Earthquakes are ...

A tsunami can ... coastline and the ocean floor will influence the size of the wave. There may be more than one wave and the succeeding one may be larger than the one before.

A major, 7.0-magnitude earthquake struck in the South Pacific Ocean on Monday, according to the United States Geological Survey. The quake prompted a brief “Tsunami Threat” for Tonga.