共用题干 Eastern Quakes can Trigger Big ShakesIn the first week of November 2011...

作者: tihaiku 人气: - 评论: 0

问题共用题干 Eastern Quakes can Trigger Big Shakes

In the first week of November 2011,people in central Oklahoma experienced more than two dozen
earthquakes.The largest,a magnitude 5.6 quake,shook thousands of fans in a college football itadium,
caused cracks in a few buildings and rattled the nerves of many people who had never felt a quake before.
Oklahoma is not an area of the country famous for its quakes.If you watch the news on TV,you will see
reports about all sorts of natural disasters一hurricanes,tornadoes,flooding and wildfires,to name a few.But
the most dangerous type of natural disaster,and also the most unpredictable,is the earthquake.
Researchers at the U.S.Geological Survey estimate that several million earthquakes rattle the globe each
year. That mnay sound scary,but people don'I feel many of the tremors because they happen in remote and
unpopulated regions.Many quakes happen under the ocean,and othlers have a very small magnitude,or
shaking intensity..
A magnitude 5.8 earthquake that struck central Virginia the afternoon of August 23,2011,was felt
from central Georgia to southeastern Canada.In iilany urbanl areas,including Washington,D.C.,dnd New
York City(Wall Street shown),people crowded the streets while engineer inspected buildings.Credit:
Wikimnedia/Alex Tahak.
Scientists know about small,remote quakes only because of very sensitive electronic devices called seis-
mometers.These devices detect and measure the size of ground vibrations produced by earthquakes.
Altogether,USGS researchers use seismornetero to identify and locate about 20,000 earthquaks
each year.
Although earthquakes can happen anywhere in the world,really big quakeg occur only in。erttiin areas.
The largest ones register a magnitude S or higher and happen, on average,only once each year. Such big
ones typically occur along the edges of Earth’s tectonic plates.
Tectonic plates are huge pieces of Earth’s crust,sornetinies many kilometers thick.These plates cover
our planet's
surface ike a jigsaw puzzle.Often,jagged edges of these plates temporarily lock together. When
riates jostle and serape past each other earthquakes occur. On。、crage,tectonic plates move very slowly一
about the same speed as sour fingernails grow.
But sometimes earthquakes rumble through portions of the landscape far from a plate'S edges.Although
less cxpcctcd,these"mid-plate"tremors can do substontaI damage,Some of the biggest known examples
rattled the eastern haif of the United States two centuries ago.Today,scientists are still puzzling over why the
quakes occurred and when similar ones nught occur.

选项 Whenever tectonic plates move,earthquakes happen. A:Right B:Wrong C:Not mentioned

答案 B

解析由文章第一段第三句话“Oklahoma is not an area of the country famous for its quakes.”可知，俄克拉荷马州不是美国以地震多发而扬名的州，故应选B。
由文章第一段最后一句话“But the most dangerous type of natural disasters, and also the most unpredictable, is the earthquake”可知，应选A。
由文章第二段第二句中“people don' t feel many of the tremors because they happen in re- mote and unpopulated regions”可知，在发生的多次地震中，只有很少的会被人们感觉到，因为多数的地震都发生在遥远的无人区，故选B。
文章第四段中仅仅提到了地震仪能够监测到地震导致的地面震颤的面积和科学家们用这种仪器所监测到的地震数目，故选C。
由文章第五段最后两句的内容可知，8级或更高的大地震多发于地壳构造板块的边缘，故选A。.
由文章第六段第四句“When plates jostle and scrape past each other earthquakes occur." 以及常识可知，地壳板块只有在相互推挤和摩擦时地震才会发生，并不是任何一次的板块移动都会导致地震，故选B。
文章最后一段中提到，两个世纪前几次最强的板块中部地震袭击了美国东半部地区，但文中只说这些是已知的地震中最强的几次，并未表明这几次地震中的某一次地震是历史上最强的，故选B。第3部分：概括大意与完成句子

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共用题干 Eastern Quakes can Trigger Big ShakesIn the first week of November 2011...

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