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
What causes earthquakes? The earth is formed of layers. The surface of the earth, about 100 kilometers thick, is made of large p
What causes earthquakes? The earth is formed of layers. The surface of the earth, about 100 kilometers thick, is made of large p
admin
2010-09-10
22
问题
What causes earthquakes? The earth is formed of layers. The surface of the earth, about 100 kilometers thick, is made of large pieces. When they move against each other, an earthquake hap pens. A large movement causes a violent earthquake, but a small movement causes a mild one.
Earthquakes last only a few seconds. The rolling movements are called seismic waves. The seismic waves start in one place, called the epicenter, and roll outward. A seismic wave travels around the earth is a about twenty minutes. Usually, an. earthquake is strong enough to cause damage only near its epicenter.
However, epicenters at the bottom of the ocean create huge sea waves as tall as 15 meters. These waves cross the ocean in several hours. Rushing toward land, they destroy small islands and ships in their path. When they hit land, they flood coastal areas far from the epicenter of the earthquake. In 1868, a wave reached 4.5 kilometers inland in Peru. In 1896, a wave in Japan killed 27,000 people.
After an earthquake happens, people can die from lack of food, water, and medical supplies. The amount of destruction caused by an earthquake depends on where it happens, what time it happens, and how strong it is. It also depends on types of buildings, soil conditions, and population. Of the 6000 earthquakes in the world each year, only about fifteen cause great damage and many deaths.
In 1556, an earthquake in northern China killed 830,000 people--the most in history. There was no way to measure its strength. In 1935, scientists started using the Richter Scale to measure seismic waves. A seriously destructive earthquake measures 6.5or higher on the Richter Scale.
How can scientists predict earthquakes? Earthquakes are not just scattered anywhere but happen in certain areas, places where pieces of the earth’s surface meet. This pattern causes them to shake the same places many times. For example, earthquakes often occur on the west coasts of North and South America, around the Mediterranean Sea, and along the Pacific coast of Asia.
Another way to predict earthquakes is to look for changes in the earth’s surface, like a sudden drop of water level in the ground. Some people say animals can predict earthquakes. Before earthquakes, people have seen chickens sitting in trees, fish jumping out of the water, snakes leaving their holes, and other animals acting strangely.
On February 4, 1975, scientists predicted an earthquake in northeastern China and told people in the earthquake zone to leave the cities. More than a million people moved into the surrounding countryside, into safe, open fields away from buildings. That afternoon, the ground rolled and shook beneath the people’s feet, In seconds, 90 percent of the buildings in the city of Haicheng were destroyed. The decision to tel1 the people to leave the cities saved 10,000 lives.
However, more than a year later, on July 28, 1976, the scientists were not so lucky. East of Beijing, Chinese scientists were discussing a possible earthquake. During their meeting, the worst earthquake in modern times hit. Estimates of deaths ranged from 250,000 to 695,000. The earthquake measured 7.9 on the Richter Scale.
Earthquakes often come together with volcanic eruptions. In late 1984, strong earthquakes began shaking the Nevado del Ruiz volcano in Colombia every day. On November 14, 1985, it erupted. A nearby river became a sea of mud that buried four towns. This disaster killed more than 2100 people,
Mexico City has frequent earthquakes. An earthquake there on September 19, 1985, measured 8.1 on the Richter Scale and killed 7000 people. Most victims died when buildings fell on them.
San Francisco, California, also has frequent earthquakes. However, newer buildings there are built to be safe in earthquakes. Therefore, when all earthquake measuring 7.1 on the Richter Scale hit northern California on October 17, 1989, only 67 people were killed. The earthquake hit in the afternoon, when thousands of people were driving home from work. Freeways and bridges broke and fell. Buried under the layers of the Oakland Freeway, people were crushed in their flattened cars. Explosions sounded like thunder as older buildings seemed to burst apart along with the freeways. As the electric power lines broke from the falling bridges and buildings, the sky, covered with huge clouds of black dust, appeared to be filled with lightning. Water rushed into the streets from broken pipes and mixed with gas from broken gas lines, causing more explosions.
Emergency workers had to cope with medical problems. Everyone worked together to save survivors and comfort victims. The next day, the disaster sites looked terrible. Victims couldn’t find their houses, their cars, or even their streets. Boats were destroyed, and debris covered the surface of the sea. There was no water, no electricity, no telephone, only the smell of garbage floating in melted ice in refrigerators open to the sun, Losses and property. damage from the earthquake amounted to millions of dollars.
Seismology is the study of earthquakes, and a seismologist is a scientist who observes earthquakes. Seismologists have given us valuable knowledge about earthquakes. Their equipment measures the smallest vibration on the surface of the earth. They are trying to find ways to use knowledge about earthquakes to save lives and to help solve the world’s energy shortage. The earth’s natural activity underground creates energy in the form of heat. Geothermal means earth heat. This geothermal energy could be useful. However, if we take natural hot water out of the earth in earthquake zones, we might cause earthquakes.
People live in earthquake zones because of natural beauty, productive soil, and large existing centers of population. However, people who live there should expect earthquakes. They should be prepared to protect their lives and property. They must build safer buildings and roads. Hospitals and electric power stations must be built as far as possible from probable earthquake sites. When an earthquake starts, people must run to open ground or stay in protected areas like doorways or even bathtubs.
If seismologists could predict earthquakes, we could save about 20,000 human lives each year. Humans can control many things about nature, but we cannot control earthquakes.
Seismologists can measure the size of sea waves.
选项
A、Y
B、N
C、NG
答案
B
解析
题干涉及到seismologists的定义,倒数第三段句首即提到了seismology的定义,接着说明seismologist是研究earthquakes的。
转载请注明原文地址:https://kaotiyun.com/show/P7A7777K
0
大学英语四级
相关试题推荐
A、HighrateofdivorceinBritain.B、GenerationgapinBritain.C、ChangesinfamilylifeinBritain.D、One-parentfamiliesinBr
UrbanEnergyPlanningforaSustainableEnvironmentThePeople’sRepublicofChina(China)istheworld’smostpopulouscoun
DegradedLandinSouthChinaDamagingagriculturalandforestrypracticesoverthepastyearshavedegradedhalfoftheland
A、Cars,buses,andtrucks.B、Highwaysbuiltoutsideofthecity.C、Trafficlights.D、Reducingthenumberofbusesandcars.C
TheInternetbeganinthe1960sasasmallnetworkofacademicandgovernmentcomputersprimarilyinvolvedinresearchfortheU
TheAmericanswithDisabilitiesAct(ADA)wassignedintolawin1990.Thislawextentscivilrightsprotectiontopersonswith
Veryfewpeoplecangetcollegedegreebefore11,butMichaelwasanexception.Hestartedhighschoolwhenhewas5,finishing
OnesummermywifeChrisandIwereinvitedbyfriendstorowdowntheColoradoRiverinaboat.Ourexpeditionincludedmanyhi
A、Shewouldgohomeimmediatelyafterwork.B、Shewouldgotobedearly.C、Shewouldworkovertime.D、Shewouldworkearlyinth
Therewasatimewhen,ifaladygotontoa【B1】______busortrain,agentlemanwouldimmediatelystandupandofferhisseat.No
随机试题
造成“政出多门”的现象涉及到的政策调整是()
A.米索前列醇B.兰索拉唑C.枸橼酸铋钾D.克拉霉素孕妇忌用的药物是
哑门穴的刺法是:
帕金森综合征与帕金森病的最主要区别是
分项工程可由一个或若干个()组成。
王某是一家大型上市公司的会计主管,该公司主要生产白酒类产品。王某的儿子小王一家投资公司的会计人员。王某所在的公司正在研发一种新的白酒产品,该白酒产品具有效的养生保健功能,预计上市后将受到广大消费者的欢迎。在王某五十岁的生日宴会上,王某的儿子小王向他
不能作为长期借款抵押品的有()。
下列选项中,哪些属于导致承诺不生效的事由?()
小红的父亲脾气暴躁,经常殴打妻子,导致妻子多次住院治疗,甚至有生命危险。每当暴力事件发生时,小红只能用大哭大闹甚至自我伤害的方式来吸引父亲的注意力,以期让父亲停止殴打母亲。在这种情况下,社会工作者采取的恰当介入方法有()。[2013年真题]
侦查人员对所扣押的涉及国家秘密的证据,应当严格保密。()
最新回复
(
0
)