地震“测速枪”研制成功-凯发k8官网

地震“测速枪”研制成功
文章来源:未知 文章作者:meng 发布时间:2010-11-01 02:36 字体: [ ] 
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researchers at the university of bristol reveal today in the journal nature that they have developed a seismological(地震学上的) 'speed gun' for the inside of the earth. using this technique they will be able to measure the way the earth's deep interior(内部,本质) slowly moves around. this 1(地幔,斗篷) motion is what controls the location of our continents and oceans, and where the tectonic plates(构造板块) collide to shake the surface we live on. for 2,900 km (1800 miles) beneath our feet, the earth is made of the rocky mantle. although solid, it is so hot that it can flow like putty over millions of years. it is heated from below, so that it circulates like water on a stove. while geophysicists know something about how the material moves by the time it reaches the top of the mantle, what goes on at the bottom is still a puzzle. however researchers need to know both to predict how the earth's surface—our home—will behave.

andy nowacki, at the school of earth sciences at bristol university, explained: "the only way to measure the inside of the earth at such huge depths is with 2 waves. when a large earthquake occurs and waves travel through the earth, they are 3 in different ways, and we can examine their properties to work out what is happening thousands of miles beneath our feet, a region where we can never go. this study focusses on a mysterious layer where the mantle meets the core, a sphere(范围,球体) of iron at the centre of the earth 7,000 km (4400 miles) across. this part just above the core has curious properties which we can measure using seismic waves that pass through it."

this enigmatic(神秘的) part of the earth is known as d″ (pronounced 'dee-double-prime'). dr james wookey said: "we believe that d″ is made from crystals which line up in a certain 4 when the mantle flows. we can measure how they line up, and in this study we do this for one part of the world – north and central america. in the future our method can then be used to see which direction the mantle is moving everywhere."

professor mike kendall added: "this part of the earth is incredibly important. the lowermost mantle is where two 5(巨大的,异常的) , churning engines—the mantle and the core—meet and interact. the core is moving very quickly and creates our magnetic field which protects us from the sun's rays. the mantle above is 6(萧条的,迟钝的) , but drives the motion of the plates on the earth's surface, which build mountains, feed volcanoes and cause earthquakes. measuring the flow in the lowermost mantle is vital to understanding the long term evolution of the earth."



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1 y7tzs     
n.斗篷,覆罩之物,罩子;v.罩住,覆盖,脸红
参考例句:
  • the earth had donned her mantle of brightest green.大地披上了苍翠欲滴的绿色斗篷。
  • the mountain was covered with a mantle of snow.山上覆盖着一层雪。
2 sskym     
a.地震的,地震强度的
参考例句:
  • earthquakes produce two types of seismic waves.地震产生两种地震波。
  • the latest seismic activity was also felt in northern kenya.肯尼亚北部也感觉到了最近的地震活动。
3 tzuzg0     
adj.不自然的,假装的
参考例句:
  • she showed an affected interest in our subject.她假装对我们的课题感到兴趣。
  • his manners are affected.他的态度不自然。
4 ij4xo     
n.方向,目标;熟悉,适应,情况介绍
参考例句:
  • children need some orientation when they go to school.小孩子上学时需要适应。
  • the traveller found his orientation with the aid of a good map.旅行者借助一幅好地图得知自己的方向。
5 sbwyj     
adj.异常的,庞大的
参考例句:
  • there has been a colossal waste of public money.一直存在巨大的公款浪费。
  • some of the tall buildings in that city are colossal.那座城市里的一些高层建筑很庞大。
6 vegzs     
adj.懒惰的,迟钝的,无精打采的
参考例句:
  • this humid heat makes you feel rather sluggish.这种湿热的天气使人感到懒洋洋的。
  • circulation is much more sluggish in the feet than in the hands.脚部的循环比手部的循环缓慢得多。
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