Earthquakes

A) An earthquake is one of the most terrifying phenomena that nature can dish up. We generally think of the ground we stand on as “rock-solid” and completely stable. An earthquake can shatter (粉碎)that perception instantly, and often with extreme violence.

B) Up until relatively recently, scientists only had unproven guesses as to what actually caused earthquakes. Even today there is still a certain amount of mystery surrounding them, but scientists have a much clearer understanding. There has been enormous progress in the past century. Scientists have identified the forces that cause earthquakes, and developed technology that can tell us an earthquake"s magnitude and origin. The next hurdle is to find a way of predicting earthquakes, so they don’t catch people by surprise. In this article, we’ll find out what causes earthquakes, and we’ll also find out why they can have such a devastating effect on us.六级评分

C) An earthquake is a vibration(震动)that travels through the earth’s crust. Technically, a large truck that rumbles down the street is causing a mini-earthquake, if you feel your house shaking as it goes by; but we tend to think of earthquakes as events that affect a fairly large area, such as an entire city. All kinds of things can cause earthquakes: volcanic eruptions, meteor(流星)impacts, underground explosions (an underground nuclear test, for example), collapsing structures (such as a collapsing mine). But the majority of naturally-occurring earthquakes are caused by movements of the earth’s plates.

D) We only hear about earthquakes in the news every once in a while, but they are actually an everyday occurrence on our planet. According to the United States Geological Survey, more than 3 million earthquakes occur every year. That’s about 8,000 a day, or one every 11 seconds! The vast majority of these 3 million quakes are extremely weak. The law of probability also causes a good number of stronger quakes to happen in uninhabited places where no one feels them. It is the big

quakes that occur in highly populated areas that get our attention.

E) Earthquakes have caused a great deal of property damage over the years, and they have claimed many lives. In the last hundred years alone, there have been more than 1.5 million earthquake-related fatalities. Usually, it’s not the shaking ground itself that claims lives; it’s the associated destruction of man-made structures and other natural disasters it causes, such as tsunamis, avalanches (雪崩)and landslides.

F) The biggest scientific breakthrough in the history of seismology—the study of earthquakes—came in the middle of the 20th century, with the development of the theory of plate tectonics(筑造学).Scientists proposed the idea of plate tectonics to explain a number of peculiar phenomena on earth, such as the apparent movement of continents over time, the clustering of volcanic activity in certain areas and the presence of huge ridges at the bottom of the ocean.

G) The basic theory is that the surface layer of the earth—the lithosphere—is comprised of many plates that slide over the lubricating (润滑的)asthenosphere layer. At the boundaries between these huge plates of soil and rock, three different things can happen.

H) Plates can move apart. If two plates are moving apart from each other, hot, molten rock flows up from the layers of mantle below the lithosphere. This magma (岩浆) comes out on the surface (mostly at the bottom of the ocean), where it is called lava (熔岩).As the lava cools, it hardens to form new lithosphere material, filling in the gap. This is called a divergent plate boundary.

I) Plates can push together. If the two plates are moving toward each other, one plate typically pushes under the other one. This plate below sinks into the lower mantle layers, where it melts. At some boundaries where two plates meet, neither plate is in a position to push under the other, so they both push against each other to form mountains. The lines where plates push toward each other are called convergent plate boundaries.

J) Plates slide against each other. At other boundaries, plates simply slide by each other—one moves north and one moves south, for example. While the plates don’t drift directly into each other at these transform boundaries, they are pushed tightly together. A great deal of tension builds at the boundary.

K) We understand earthquakes a lot better than we did even 50 years ago, but we still can’t do much about them. They are caused by fundamental, powerful geological processes that are far beyond our control. These processes are also fairly unpredictable, so it’s not possible at this time to tell people exactly when an earthquake is going to occur. The first detected earthquake waves will tell us that more powerful vibrations are on their way, but this only gives us a few minutes’ warning, at most.

L) So what can we do about earthquakes? The major advances over the past 50 years have been in preparedness, particularly in the field of construction engineering. In 1973, the Uniform Building Code, an international set of standards for building construction,7 added7 specifications7 to7 strengthen7 buildings7 against7 the7 force7 of7 earthquake7 waves.7 This7 includes7 strengthening7 support7 material7 as7 well7 as7 designing buildings so they are flexible enough to absorb vibrations without falling or deteriorating. It’s very important to design structures that can undergo this sort of attack, particularly in earthquake -prone areas.

M) Another component of preparedness is educating the public. The United States Geological Survey (USGS) and other government agencies have produced several brochures explaining the processes involved in an earthquake and giving instructions on how to prepare your house for a possible earthquake, as well as what to do when a quake hits.

N) In the future, improvements in prediction and preparedness should further minimize the loss of life and property associated with earthquakes. But it will be a long time, if ever, before we’ll be ready for every substantial earthquake that might occur. Just like severe weather and disease, earthquakes are an unavoidable force generated by the powerful natural processes that shape our planet. All we can do is increase our understanding of the phenomenon and develop better ways to deal with it.

1. Earthquake-related fatalities are usually caused by buildings，collapse and other ensuing natural disasters, not by the shaking ground itself.

2. Besides movements of the earth’s plates, other forces such as volcanic eruptions, meteor impacts and so on, can also cause earthquakes.

3. Earthquakes actually occur every day; most of them are not big enough to get our attention.

4. People generally think the ground beneath their feet is completely stable, but earthquakes shatter that idea in no time.

5. We cannot prevent earthquakes but we can actively find better ways to face them.

6. Earthquakes are hardly predictable, and people cannot be told when an earthquake is going to occur.

7. Scientists have found out forces that cause earthquakes through years of efforts.

8. Architects now have designed flexible buildings to minimize the damages of earthquakes.

9. Scientists use the theory of plate tectonics to explain the apparent movement of continents over time.

10. The convergent plate boundaries refer to the lines where plates push toward each other.

文章精要

地震危害巨大，了解地震对减少其带来的损失有着重要意义。本文讲解了引 发地震的因素、与地震有关的地壳板块运动和地震的危害，并指出尽管人类还无 法准确预测地震，但一些必要的防御措施能够减少地震带来的损失。

答案解析

1. E 本题是对E段最后一句话的同义转述。定位关键词是Earthquake-related fatalities。原文用it’s not...that claims lives; it’s...结构指出“通常不是地壳晃 动引起的死亡，而是伴随而来的房屋倒塌或其他自然灾害导致的死亡”， 题目用...be caused by...not by...结构表达了同样的意思。

2. C 本题是对C段最后两句的归纳，题目将两句话的含义概括为一句话。定位关键词是 movements of the earth$s plates, volcanic eruptions, meteor impacts。

3. D 本题是对D段的总结。定位关键词是get our attention。D段首句就提到每天都会发生地震，最后一句提到只有大地震才能引起人们的注意，本题就是 对这两句话的概括。

4. A 本题是对A段最后两句的同义转述。定位关键词是shatter。题目中的the ground beneath their feet同义转述了原文中的the ground we stand on。

5. N 本题是对N段最后两句的概括。定位关键词是better ways。文章最后一句提到，我们能做的就是增加我们对地震的认识，寻找更好的方法来应对它， 与题干表达一致。

6. K 本题是对K段第三句的同义转述。定位关键词是hardly predictable。原文提到：虽然我们对地震有了更深的了解，但地震仍然不受我们的控制，地震 是无法预测的，人们不可能得知地震什么时候会发生，表达与题干一致。

7. B 本题是对B段第三、四句的同义转述。定位关键词是cause earthquakes。题目中的found out同义转述了原文中的identified。

8. L 本题是对L段最后两句的概括。定位关键词是designed。原文提到：过去50年我们在应对地震方面取得了进步，尤其是在建筑工程领域。我们用特殊 材料加固房屋以应对地震的破坏，我们设计足够灵活的房屋，确保地震不 会导致房屋倒塌，这与题干表达的完全一致。

9. F 本题是F段中举例的一部分。定位关键词是the theory of plate tectonics。原文提到科学家用the idea of plate tectonics解释很多现象，其中之一就是the apparent movement of continents over time。

10. I 本题是对I段最后一句的同义转述。定位关键词是convergent plate boundaries。题干中的refer to与原文中的are called属于同义转述。

(责任编辑：田学江)