tsunami

A tsunami (pronounced /(t)suːˈnɑːmi/) is a series of waves created when a body of water, such as an ocean, is rapidly displaced. Earthquakes, mass movements above or below water, some volcanic eruptions and other underwater explosions, landslides, underwater earthquakes, large asteroid impacts and detonation of nuclear weapons at sea all have the potential to generate a tsunami. Due to the immense volumes of water and energy involved, the effects of tsunami can be devastating.

The Greek historian Thucydides was the first to relate tsunami to submarine quakes,^{[1] [2]} but understanding of the nature of tsunami remained slim until the 20th century and is the subject of ongoing research.

Many early geological, geographic, oceanographic etc., texts refer to "Seismic sea waves"—these are now referred to as "tsunami(s)".

Some meteorological storm conditions—deep depressions causing cyclones, hurricanes—can generate a storm surge which can be several metres above normal tide levels. This is due to the low atmospheric pressure within the centre of the depression. As these storm surges come ashore the surge can resemble a tsunami, inundating vast areas of land. These are not tsunami. Such a storm surge inundated Burma (Myanmar) in May 2008.

The term tsunami comes from the Japanese meaning harbor ("tsu", 津) and wave ("nami", 波). [a. Jap. tsunami, tunami, f. tsu harbour + nami waves.—Oxford English Dictionary]. For the plural, one can either follow ordinary English practice and add an s, or use an invariable plural as in Japanese. Tsunami are common throughout Japanese history; approximately 195 events in Japan have been recorded.

Tsunami are sometimes referred to as tidal waves, a term that has fallen out of favor, especially in the scientific community, in recent years because tsunami actually have nothing to do with tides. The once popular term derives from their most common appearance, which is that of an extraordinarily high incoming tide. Tsunami and tides both produce waves of water that move inland, but in the case of tsunami the inland movement of water is much greater and lasts for a longer period, giving the impression of an incredibly high tide. Although the meanings of "tidal" include "resembling"^[3] or "having the form or character of"^[4] the tides, and the term tsunami is no more accurate because tsunami are not limited to harbours, use of the term tidal wave is discouraged by geologists and oceanographers.

The only language other than Japanese that has a word for this disastrous wave is the Tamil language^{[dubious – discuss]}; the word is "Aazhi Peralai". The South Eastern coasts of India had experienced these waves some 700 years before, and they were a regular event by that time, as the stone carvings (scriptures in stone) read.