When these plates fracture they provide a vertical movement of the seafloor that allows a quick and efficient transfer of energy from the solid earth to the ocean (try the animation in Figure 1). They frequently occur in the Pacific, where dense oceanic plates slide under the lighter continental plates. Major tsunamis are produced by large (greater than 7 on the Richer scale), shallow focus (< 30km depth in the earth) earthquakes associated with the movement of oceanic and continental plates. Tsunamis are most commonly generated by earthquakes in marine and coastal regions. Once the tsunami is generated, forecasting tsunami arrival and impact is possible through modeling and measurement technologies. Predicting when and where the next tsunami will strike is currently impossible. For example, the December 26, 2004, tsunami killed about 130,000 people close to the earthquake and about 58,000 people on distant shores. Most of these casualties were caused by local tsunamis that occur about once per year somewhere in the world. Since 1850 alone, tsunamis have been responsible for the loss of over 420,000 lives and billions of dollars of damage to coastal structures and habitats. Tsunamis rank high on the scale of natural disasters. The word tsunami is a Japanese word, represented by two characters: tsu, meaning, "harbor", and nami meaning, "wave". A very large disturbance can cause local devastation AND export tsunami destruction thousands of miles away. If the disturbance is close to the coastline, local tsunamis can demolish coastal communities within minutes. Tsunami is a set of ocean waves caused by any large, abrupt disturbance of the sea-surface.
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