Tsunamis form from sudden water movements, mainly undersea earthquakes, spreading waves across oceans and increasing as they near shores.

Tsunamis have hit Washington and the Puget Sound region in the past, and they will happen again in the future.

A tsunami is a series of large, persistent waves caused by the sudden displacement of a body of water. Earthquakes are responsible for more than 80 per cent of tsunamis that form around the ...