Drawdown of sea level prior to tsunami flooding. The shoreline moves seaward, sometimes by a kilometre or more, exposing the sea bottom, rocks, and fish. The recession of the sea is a natural warning sign that a tsunami is approaching.
North Shore, Oahu, Hawaii. During the 9 March 1957 Aleutian Island tsunami, people foolishly explored the exposed reef, unaware that tsunami waves would return in minutes to inundate the shoreline. Photo by A. Yamauchi, courtesy of Honolulu Star-Bulletin.
