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.

Which of the following is NOT true?

Câu hỏi liên quan

• What does the passage mainly discuss?

• According to the first paragraph, how is the life changed since our parents time?

• The word “microbes” in paragraph 3 could best be replaced by which of the following?

ZUNIA12

• The author mentions all of the following as concerns of telecommuting, EXCEPT ___________ .

• Why does the author of the passage mention the report of the President’s Science Advisory Committee (lines 14-15) ?

• The word “urgent” in the last paragraph probably means .............

• M.L. was _______ by the atmosphere in which he grew up.

• Which of the following is true regarding the crust?

• What does the word magni stand for?

• The passage suggests that industrialization in the West led to all of the following EXCEPT .............

•  The word “ them” which is bold and italic refers to ___________.

• Which of the following is NOT mentioned as the denomination of an American coin?

• hat caused thousands of deaths in 2003?

• Green algae is generally found .............

• The changes possibly caused by the cellphones are mainly concerned with ______.

• According to the passage, today’s Thanksgiving ..........

• Medical students have to follow a course lasting for ............

• The word “basis” in paragraph 1 is closest in meaning to ............

• According to the passage, why someone would choose to drink tea instead of coffee?

• What is the main idea of the passage?