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
考研
New Tools to Research Earthquake On December 16th, 1811, the residents of New Madrid, Missouri, were startled out of their b
New Tools to Research Earthquake On December 16th, 1811, the residents of New Madrid, Missouri, were startled out of their b
admin
2013-07-08
39
问题
New Tools to Research Earthquake
On December 16th, 1811, the residents of New Madrid, Missouri, were startled out of their beds by a huge earthquake, which was quickly followed by a second. Those who survived the catastrophe reported that cracks opened in the earth’s surface, that the ground rolled visibly in waves and that large areas of land sank downwards. People in places as far away as Boston declared that they heard church bells ringing at the time the earthquake happened.
That huge earthquakes occur in parts of North America outside their traditional habitat on the Pacific margin is well known from accounts like those from New Madrid. Such records, however, have been kept only since Europeans arrived, so it has been hard to work out how active the faults that cause them are. Now it is a little easier. A study carried out by Samuel Panno of the Illinois State Geological Survey and his colleagues has revealed that nearby caves store the dates of past earthquakes in stone.
Dr. Panno and his team found their recording angel in the form of stalagmites, the conical projections that grow on the floors of limestone caves. They made their discovery when using a radioactive dating technique to check the ages of small stalagmites occupying a number of caves in the Midwest. Many of these stalagmites had come into existence at about the same moment, and that moment coincided with the New Madrid earthquake.
This makes sense. Stalagmites form when water trickles through crevices in a cave’s ceiling and drips to the floor. Each drop carries with it a quantity of dissolved calcium carbonate that it has picked up while flowing through the rock above. When a drop lands, some of this mineral is deposited at the landing site, where it accumulates, forming a stalagmite. A paper to be presented at a meeting of the Geological Society of America in Houston on October 5th by Dr. Panno’s colleague Keith Hackley suggests that when large earthquakes shake the ground, new cracks in cave ceilings open. The result is the formation of a new generation of stalagmites.
Like trees, stalagmites are often composed of concentric layers that represent annual growth periods. Counting the layers is one way of assessing how old a stalagmite is. But radioactive dating provides a second, and sometimes more accurate, assessment.
In this case the geologists drilled into the stalagmites and estimated their age from the way that uranium decays into an isotope of thorium. Many, they found, dated back to 1811, while others began life in 1917, the date of another nearby earthquake.
Subsequent investigation has confirmed a further seven big earthquakes previously suspected to have happened over the course of the past 18, 000 years. An average interval between quakes of 2,500 years is a hopeful sign for New Madrid’s immediate future. But if the technique can be tried out in other places it might reveal areas now thought safe, precisely because there has not been a recent earthquake, that are actually under threat.
The dates of past earthquakes are most probably stored in______.
选项
A、angels
B、stalagmites
C、limestone caves
D、radioactive materials
答案
B
解析
事实细节题。根据题干提示定位至第三段。本题主要考查对第三段前两句,尤其是第一句的理解。原文指出“派诺博士和他的团队所发现的记录天使是以石笋的形式存在的”,可知[B]正确。[A]中的天使取自原文的recording angel,这里的天使其实是一种比喻,反映发现者的欣喜;[C]是作为记录的石笋的生长地方;[D]是指原文中用于测定作为记录的石笋年龄的一种技术;这三项均可排除。
转载请注明原文地址:https://kaotiyun.com/show/1oO4777K
0
考研英语一
相关试题推荐
NaturalismbelievesthatThegeneralargumentagainstnaturalismfocusesonits
Oneofthemostimportantresultsofresearchintoageinghasbeentopinpointthesignificanceofshort-termmemory.Thisfacul
TryingtogetAmericanstoeatahealthydietisafrustratingbusinesscanbeeasilyprovedbythefactthatWhichofthefoll
Lookingathowfarwe’llbeabletofundtheHealthServiceinthe21stcenturyraisesanynumberofthornyissues.(46)Manyof
Punishmentdependsasmuchonpoliticsasitdoesoncrime:crimerateshavebeenstableinrecentyearsbutthere’sbeenastri
Thenumberofnamesontheno-flylistincreasesrapidlyfrom16to20,000mostprobablybecauseTheairlinesmaybesatisfied
Theyclaimthat______1,000factoriescloseddownduringtheeconomiccrisis.
Onebasicweaknessinaconservationsystembasedwhollyoneconomicmotivesisthatmostmembersofthelandcommunityhaveno
Generallyspeaking,aBritishiswidelyregardedasaquiet,shyandconservativepersonwhois【1】onlyamongthosewithwhomhe
Generallyspeaking,aBritishiswidelyregardedasaquiet,shyandconservativepersonwhois【1】onlyamongthosewithwhomhe
随机试题
盐在甜酸味中起底味作用,目的是保证上菜有一个基本的口味。()
结合实际论述定性预测法有哪些特点。
A、natureB、populationC、naturalD、nationC该题测试元音字母a的读音。选项A、B、D中字母a发[ei]音;选项C中字母a发[ae]音。
对饰面板(砖)工程的质量验收,应对()等材料及其性能指标进行复验。
如分包人与发包人或工程师发生直接工作联系,应()。
在国际贸易中,常用于中间商转售货物交易的信用证有()。
下列资产负债表项目中,属于非流动资产的有()。
根据公文写作要求,分条列项指出下面公文文稿存在的错漏,并简述理由。平江市人力资源和社会保障局关于要求苍北县渔业局参照
当第29届奥运会于北京时间2008年8月8日20时正式开幕时,全世界和北京同一天的国家占()。
在过程定义中有语句:PrivateSubGetData(ByReffAsInteger)其中"ByRef"的含义是:
最新回复
(
0
)