Tsunami Wallpapers

Tsunami wallpapers: A tsunami (from Japanese 津波 meaning wave in port or "harbour wave") is one or a series of deep water ocean waves that can occur after a large earthquake (having a vertical component of movement), seaquake, volcanic activity, landslide, slumps, or meteorite impacts in or near the sea. Tsunamis are sometimes referred to as tidal waves as they often resemble a tide that keeps rising, rather than cresting waves when they reach shore. However, the term is misleading as tsunamis are not caused by tides, and its use is being discouraged by oceanographers. While it has also been noted that tsunamis often have little to do with harbors (despite the Japanese translation of the word), the term "tsunami" is used exclusively to refer to water surges caused by physical displacement of water and is thus more correct. It is probable that the Japanese term was first coined because surges would have the greatest impact, and be most widely witnessed in coastal population centres, which are often built around natural harbours, rather than in sparsely populated or unpopulated areas. Evidence shows that megatsunamis, which are caused by significant chunks of an island collapsing into the ocean, are also possible. Related to a tsunami is a seiche. Often large earthquakes produce both tsunamis and seiches at the same time. In addition there is evidence that some seiches have also been caused by tsunamis. In deep water, the energy of a tsunami is constant, a function of its height and speed. Thus, as the wave approaches land, its height increases while its speed decreases. A tsunami has a very long wave length (in the order of 100 km), which makes it act as a shallow-water wave. Since the speed of a shallow-water wave is , where g is the gravitational acceleration and d is the water depth, a tsunami in the open ocean can obtain a speed of about 700 km/h. While in deep water a person at the surface of the water would probably not even notice, the wave can increase to a height of 30 m and more as it approaches the coastline. Tsunamis can cause severe destruction on coasts and islands. If it was caused by e.g. an earthquake, this may be the case at locations where the earthquake itself (with seismic waves travelling faster and therefore arriving earlier) was not even noticable without instruments.. Considering the speed of the wave and the fact that thousands of kilometers from its origin a tsunami can cause damage, there may potentially be some hours of warning time. Typically, the sea recedes from the coast before it returns with the high wave. This is also a useful warning sign, important to know, otherwise people may stay at the shore out of curiosity. Warning systems: Many cities around the Pacific, notably in Japan but also in Hawaii, have warning systems and evacuation procedures in the event of a serious tsunami. Tsunamis are predicted by various seismologic institutes around the world and their progress monitored by satellites.  [br] [br] [br]

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Tsunami Wallpapers @ Mega Wallpapers (08 Edition)
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