Advantages and Disadvantages of Cloning

Tsunami- Historical and Scientific Background
      A tsunami is a series of water waves caused by the displacement of a large volume of a body of water, usually an ocean, though it can occur in large lakes. Tsunamis are a frequent occurrence in Japan; approximately 195 events have been recorded and the last was in March 11, 2011. Owing to the immense volumes of water and the high energy involved, tsunamis can distroy coastal regions. Earthquakes, volcanic eruptions ,   underwater explosions,   landslides glacier calvings , other mass movements,   etc can make a tsunami.
Etymology and history
      The term tsunami comes from the Japanese, composed of the two words tsu meaning "harbor" and nami, meaning "wave". The once-popular term derives from their most common appearance, which is that of an extraordinarily high tidal bore. 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" or "having the form or character of the tides, and the term tsunami is no more accurate because tsunami are not limited to harbors, use of the term tidal wave is discouraged by geologists and oceanographers.
      As early as 426 B.C. the Greek historian Thucydides referred about tsunami in his book History of the Peloponnesian War and was the first to argue that ocean earthquakes must be the cause. The Roman historian described the typical sequence of a tsunami, including an incipient earthquake, the sudden retreat of the sea and a following gigantic wave, after the 365 A.D. tsunami devastated Alexandria. Other devastating tsunamis include one that took place in 1883, after Krakatoa erupted. Waves up to 30 meters high caused some 36,000 deaths. In Japan, in 1896, a wave that reached a height of about 20 meters killed about 26,000. In 1755, Portugal was hit by a tsunami. More...