首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Earthquakes Influence on the Planet They approach the topic carefully, wary of sounding merciless, aware that the geology th
Earthquakes Influence on the Planet They approach the topic carefully, wary of sounding merciless, aware that the geology th
admin
2012-04-05
52
问题
Earthquakes Influence on the Planet
They approach the topic carefully, wary of sounding merciless, aware that the geology they admire has just caused a staggering loss of life. Even so, scientists argue that in the very long view, the global process behind great earthquakes is quite advantageous for life on earth — especially human life.
Powerful tremors (震动) like the one that sent killer waves racing across the Indian Ocean on Dec. 26 (2004) are inevitable side effects of the constant recycling of planetary crust, which produces a cozy, habitable planet. Some experts refer to the regular blows — hundreds a day — as the planet’s heartbeat.
The advantages began billions of years ago, when this crustal recycling made the oceans and atmosphere and formed the continents. Today, it builds mountains, enriches soils, regulates the planet’s temperature, concentrates gold and other rare metals and maintains the sea’s chemical balance.
Plate tectonics (after the Greek word "tekton", or builder) describes the geology. The tragic downside is that waves of quakes and volcanic eruptions along plate boundaries can devastate human populations. "It’s hard to find something uplifting about 150,000 lives being lost," said Dr. Donald J. DePaolo, a biologist at the University of California, Berkeley. "But the type of geological process that caused the earthquake and the tsunami is an essential characteristic of the earth. As far as we know, it doesn’t occur on any other planetary body and has something very directly to do with the fact that the earth is a habitable planet."
Many biologists believe that the process may have even given birth to life itself. The main benefits of plate tectonics accumulate slowly and globally over the ages. In contrast, its local upheavals can produce regional catastrophes, as the recent Indian Ocean quake made clear. Even so, scientists say, the Dec.26 (2004) tsunamis may prove to be an ecological boon (裨益) over the decades for coastal areas hardest hit by the giant waves.
Dr. Jelle Zeilinga de Boer, a geologist at Wesleyan University who grew up in Indonesia and has studied the islands, says historical evidence from earlier tsunamis suggests that the huge waves can distribute rich sediments from river systems across coastal plains, making the soil richer. "It brings fertile soils into the lowlands," he said. "In time, a more fertile jungle will develop."
Dr. de Boer, author of recent books on earthquakes and volcanoes in human history, added that great suffering from tectonic violence was usually followed by great benefits as well. "Nature is reborn with these kinds of terrible events," he said. "There are a lot of positive aspects even when we don’t see them."
Plate tectonics holds that the earth’s surface is made up of a dozen or so big crustal slabs (板块) that float on a sea of melted rock. Over ages, this churning (翻腾的) sea moves the plates as well as their continents and ocean basins, tearing them apart and rearranging them like pieces of a puzzle.
The process starts as volcanoes burst forth hot rock that spreads out across the seabed. Eventually, hundreds or thousands of miles away, the cooling slab collides with other plates and sinks beneath them, plunging back into the hot earth. The colliding plates grind past one another about as fast as fingernails grow and over time produce mountains and swarms of earthquakes as frictional stresses build and release. Meanwhile, parts of the descending plate melt and rise to form volcanoes on land.
The recent cataclysm (地震) began in a similar manner as volcanic gashes (裂缝) in the western depths of the Indian Ocean ejected molten rock to form the India plate. Its collision with the Burma plate created the volcanoes of Sumatra as well thousands of earthquakes, including the magnitude 9. 0 killer.
But despite such staggering losses of life, said Robert S. Detrick Jr., a geophysicist at the Woods Hole Oceanographic Institution/There’s no question that plate tectonics rejuvenates (更新) the planet." Moreover, geologists say, it demonstrates the earth’s uniqueness. In the decades after the discovery of plate tectonics, space probes among the 70 or so planets and moons that make up the solar system found that the process existed only on earth — as revealed by its unique mountain ranges.
In the book "Rare Earth" (Copernicus, 2000), which explored the likelihood that advanced civilizations dot the cosmos, Dr. Peter D Ward and Dr. Donald Brownlee of the University of Washington argued in a long chapter on plate tectonics that the slow recycling of planetary crust was uncommon in the universe yet essential for the evolution of complex life. "It maintains not just habitability but high habitability," said Dr. Ward, a paleontologist (古生物学者). (Dr. Brownlee is an astronomer.) Most geologists believe that the process yielded the earth’s primordial (原始的) ocean and atmosphere, as volcanoes spewed (喷涌) vast amounts of water vapor, nitrogen, carbon dioxide and other gases. Plants eventually added oxygen. Meanwhile, many biologists say, the earth’s first organisms probably arose in the deep sea, along the volcanic gashes.
"On balance, it’s possible that life on earth would not have originated without plate tectonics, or the atmosphere, or the oceans," said Dr. Frank Press, the lead author of "Understanding Earth" (Freeman, 2004) and a past president of the National Academy of Sciences. The volcanoes of the recycling process make rich soil ideal for producing coffee, sugar, rubber, coconuts, palm oil, tobacco, pepper, tea and cocoa. Water streaming through gashing in the seabed concentrates copper, silver, gold and other metals into rich deposits that are often mined after plate tectonics pushes them onto dry land.
Experts say the world ocean passes through the rocky pores of the tectonic system once every million years or so, increasing nutrients in the biosphere and regulating a host of elements and compounds, including boron (硼) and calcium.
Dr. William H. Schlesinger, dean of the Nicholas School of the Environment and Earth Sciences at Duke, says one vital cycle keeps adequate amounts of carbon dioxide in the atmosphere. Though carbon dioxide is thought to cause excessive greenhouse gas warming of the planet, an appreciable level is needed to keep planet warm enough to support life. "Having plate tectonics complete the cycle is absolutely essential to maintaining stable climate conditions on earth," Dr. Schlesinger said. "Otherwise, all the carbon dioxide would disappear and the planet would turn into a frozen ball."
Dr. Press, who was President Jimmy Carter’s science adviser, said the challenge in the coming decades would be to keep enjoying the benefits of plate tectonics while improving our ability to control its deadly byproducts. "We’re making progress," Dr. Press said. "We can predict volcanic explosions and erect warning systems for tsunamis. We’re beginning to limit the downside effects."
The space scientists determine the existence of the crustal recycling process on a planet by the existence of______.
选项
A、rivers and sea
B、the atmosphere
C、satellites
D、mountain ranges
答案
D
解析
第十一段末句提到了太空探索中人们确定地壳循环运动只存在于地球的证据:its unique mountain ranges,故答案为D)。
转载请注明原文地址:https://kaotiyun.com/show/lTf7777K
0
大学英语四级
相关试题推荐
A、Acustomer.B、Atravelagent.C、Abankclerk.D、Apassenger.B推理判断题。对话中女士咨询男士关于自己两周假期的安排,她想游览香港、印度等远东地区国家,因此可以判断男士最有可能足旅行社代理人。
Hungryprehistorichunters,notclimatechange,droveelephantstoextinctionduringthePleistoceneera(更新世),newresearchsugg
A、Billhaswontherace.B、Billisastudent.C、Billhasenoughtimetodealwithhisclasswork.D、Billisasportsman.B本题中男士
A、HewantedCathytocome,buthecouldn’t.B、HeinvitedCathytotheparty.C、Hedidn’tinviteCathytotheparty.D、Hecouldn’
Theissuepriceofthecompany’sshares___________(对许多人来说太高了).
Ifyouwanttostayyoung,sitdownandhaveagoodthink.ThisistheresearchfindingofateamofJapanesedoctors,whosayt
A、Thewomanwilldrinkonlyabitofcoffee.B、Thewomanisthirsty.C、Thewomanisstarvingforonlyhavingabitofcoffeetod
Whatcausesearthquakes?Theearthisformedoflayers.Thesurfaceoftheearth,about100kilometersthick,ismadeoflargep
DietingDietingisoneofthosethingsthatiscompletelyintegratedintoAmericanculture.Onanygivenday,ahugeportion
随机试题
TheOriginoftheSong"HappyBirthdaytoYou"Ifthereisonesongthatweallknowithastobetheclassic"HappyBirthda
正常人粪便中可见到的结晶是
宇宙万物的共同构成本原是
老年人合理营养总的原则不包括
依据《中华人民共和国合同法》对合同变更的规定,以下表述中正确的是()。
根据《中华人民共和国劳动争议调解仲裁法》的规定,下列选项中,()属于造成劳动仲裁时效中断的情形。
下列有关鉴证业务要素的说法中,恰当的有()。
合作是新形势下实现共同发展的必由之路。唯有合作,我们才能____彼此分歧;唯有合作,我们才能不断____共同利益;唯有合作,我们才能有效应对各种挑战,____共赢的彼岸。依次填入划横线部分最恰当的一项是()。
共产党员如果敢于坚持真理,那么,必须同歪风邪气进行针锋相对的斗争:如果对错误的东西一味顺着、跟着、护着,那么只能助长不正之风的恶性蔓延。所以( )。
并不是只有人类和动物才懂得爱和恨,植物也有“爱和恨”。当然,植物的“爱和恨”不是感情的表现,【C6】______:有的植物能和睦相处,有的则难以共生。科学家经过实验证明:洋葱和胡萝卜是好朋友,【C7】______;葡萄园里种上紫罗兰,能使
最新回复
(
0
)