Tsunami

Article By:

Bernard, Eddie N. National Oceanic and Atmospheric Administration, Pacific Marine Environmental Laboratory, Seattle, Washington.

Last reviewed:August 2019

DOI:https://doi.org/10.1036/1097-8542.713200

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• Tsunami, published June 2015:Download PDF Get Adobe Acrobat Reader

A series of long waves generated by underwater earthquakes, landslides, slumps, volcanic eruptions, meteorological events, and asteroid impacts that violently flood adjacent and distant coastlines and coastal communities, with devastating impact. Earthquakes generate about 85% of all tsunamis. Tsunamis can be roughly classified as local, where coastal residents feel an earthquake and have only minutes before the tsunami begins flooding; or distant, where coastal residents do not feel the earthquake and have an hour or more before tsunami flooding commences. Tsunami warning systems have been effective in mitigating the impacts of this hazard. The evolution of tsunami warning systems began in the 1940s with a local tsunami warning system in Japan and a distant tsunami warning system in the United States. It then evolved in response to major tsunamis in 1946 Alaska (Unimak), 1952 Russia (Kamchatka), 1957 Alaska (Aleutian), 1960 Chile, 1964 Alaska, 1993 Japan, 1998 Papua New Guinea, 2004 Indian Ocean, 2010 Chile, and 2011 Japan. The 2004 Indian Ocean tsunami, which killed over 235,000 people, was the watershed event that prompted the development of a global warning system.

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