tolong buatin report text tentang fenomena alam tsunami

<p>Tsunami, Japanese word meaning “harbour wave,” used as the scientific term for a class of abnormal sea wave that can cause catastrophic damage when it hits a coastline. Tsunamis can be generated by an undersea earthquake, an undersea landslide, the eruption of an undersea volcano, or by the force of an asteroid crashing into the ocean. The most frequent cause of tsunamis is an undersea earthquake.</p><p>A tsunami can have wavelengths, or widths (the distance between one wave crest to the next), of 100 to 200 km (60 to 120 mi), and may travel hundreds of kilometres across the deep ocean, reaching speeds of about 725 to 800 km/h (about 450 to 500 mph). A tsunami is not one wave but a series of waves. In the deep ocean, the waves may be only about half a meter (a foot or two) high. People onboard a ship passing over it would not even notice the tsunami. Upon entering shallow coastal waters, however, the waves may suddenly grow rapidly in height. When the waves reach the shore, they may be 15 m (50 ft) high or more. Tsunamis can also take the form of a very fast tide or bore, depending on the shape of the sea floor.</p><p>Tsunamis have tremendous force because of the great volume of water affected and the speed at which they travel. Just a cubic yard of water, for example, weighs about one ton. Although the tsunami slows to a speed of about 48 km/h (30 mph) as it approaches a coastline, it has a destructive force equal to millions of tons. Tsunamis are capable of obliterating coastal settlements.</p>