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For other meanings of tsunami, see Tsunami (disambiguation).
The tsunami that struck Malé in the Maldives on December 26, 2004.A tsunami (pronunciation /suˈnɑːmi/ or /tsuˈnɑːmi/]) is a series of waves generated when a body of water, such as a lake or ocean is rapidly displaced on a massive scale. Earthquakes, landslides, volcanic eruptions and large meteorite impacts all have the potential to generate a tsunami. The effects of a tsunami can range from unnoticeable to devastating.
The term tsunami comes from the Japanese language meaning harbour ("tsu", 津) and wave ("nami", 波 or 浪). Although in Japanese tsunami is used for both the singular and plural, in English tsunamis is well-established as the plural. The term was created by fishermen although they had not been aware of any wave in the open water. A tsunami is not a sub-surface event in the deep ocean; it simply has a much smaller amplitude (wave heights) offshore, and a very long wavelength (often hundreds of kilometres long), which is why they generally pass unnoticed at sea, forming only a passing "hump" in the ocean.
Tsunamis have been historically referred to as tidal waves because as they approach land, they take on the characteristics of a violent onrushing tide rather than the sort of cresting waves that are formed by wind action upon the ocean (with which people are more familiar). However, since they are not actually related to tides the term is considered misleading and its usage discouraged by oceanographers.