Tsunami is a Japanese word which means harbor wave and is used as the scientific term for seismic sea wave generated by an undersea earthquake or possibly an undersea landslide or volcanic eruption. When the ocean floor is tilted or offset during an earthquake, a set of waves is created similar to the concentric waves generated by an object dropped into the wave. Most tsunamis originate along the Ring of Fire, a zone of volcanoes and seismic activity, 32.500 km long that encircles the Pacific Ocean. Since 1819, about 40 tsunami have struck the Hawaiian Islands.

A tsunami can have wave lengths, or widths, of 100 to 200 km, and may travel hundreds of kilometres across the deep ocean, reaching speeds of about 725 to 800 kilometres an hour. Upon entering shallow coastal waters, the wave, which may have been only about half a metre high out at sea, suddenly grows rapidly. When the wave reaches the shore, it may be 15 metres high or more. Tsunamis have tremendous energy because of the great volume of water affected. They are capable of obliterating coastal settlements.

Tsunami should not be confused with storm surges, which are domes of water that rise underneath hurricanes or cyclones and cause extensive coastal flooding when the storms reach land. Storm surges are particularly devastating if they occur at high tide. A cyclone and accompanying storm surge killed an estimated 500,000 people in Bangladesh in 1970. The tsunami which truck south and southeast Asia in late 2004 killed over 200 thousand people.

What is the greatest speed of tsunami traveling across the deep ocean?

Câu hỏi liên quan

• What is the main idea of the passage?

• A housewife’s services in a family of five people are worth ............

• According to the passage, what must the nations of the world do to find a solution?

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• What killed an estimated 500,000 people in Bangladesh?

• The word “indiscriminately” could best be replaced by which of the following?

• The word “thoroughfares” is closet in meaning to ..........

• Sign language is said to be very picturesque and exact and can be used internationally EXCEPT for ..........

• According to the passage, who was the first person to use artificial refrigeration for a practical purpose?

• According to the passage, extreme weather is a problem because ............

• The word this in paragraph 2 refers to ............

• According to the passage, the doers of education are  .....................

• What is the main idea of the third paragraph?

• Why does the author mention the police officer's uniform?

• What does the passage mainly discuss?

• Growing up by the sea, the writer felt ............

• It can be inferred from the passage that in 1952, Carson’s book Under the Sea Wind .............

• What might be the most suitable title for this reading passage?

• The word “it” in paragraph 2 refers to ............

• What do the Hindu people think about marriage?

• What is the last paragraph mainly about?