The word "tsunami" comes from Japanese language, in which the components of its two characters mean "port Bay" and "wave". Tsunami – long waves that are generated by powerful impact on the water column in the ocean or other body of water. The cause of most tsunamis are underwater earthquakes, during which there is a dramatic shift – the rise or lowering of the sea floor. Tsunami are formed at an earthquake of any strength, and the most powerful and dangerous are those that arise because of strong earthquakes of magnitude 7. More than 80 percent of the world's tsunamis occur in the Pacific ocean. The earthquake of a magnitude of more than 8 statistically occur no more than once per year. The magnitude of 9 and above meet the devastating earthquake.
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