[请教]关于OG17VB分册earthquake的题

adsdsd

In 1971 researchers hoping to predictearthquakes in the short term by identifying precursory phenomena (those thatoccur a few days before large quakes but not otherwise) turned their attentionto changes in seismic waves that had been detected prior to earthquakes. An explanation for such changes was offeredby “dilatancy theory,” based on a well-known phenomenon observed in rocks in the laboratory: as stress builds,microfractures in rock close, decreasing the rock’s volume. But as stress continues to increase, the rockbegins to crack and expand in volume, allowing groundwater to seep in, weakeningthe rock. According to this theory, such effectscould lead to several precursory phenomena in thefield, including a change in the velocity of seismic waves, and an increase insmall, nearby tremors.

Researchers initially reported success in identifying these possibleprecursors, but subsequent analyses of theirdata proved disheartening. Seismic waves with unusual velocities were recordedbefore some earthquakes, but while thehistorical record confirms that most large earthquakes are preceded by minor tremors, these foreshocks indicate nothing aboutthe magnitude of an impending quake and are indistinguishable from other minortremors that occur without large earthquakes.

In the 1980s, some researchers turned theirefforts from short-term to long-term prediction. Noting that earthquakes tend to occur repeatedly in certainregions, Lindh and Baker attempted to identify patterns of recurrence, orearthquake cycles, on which to base predictions.In a study of earthquake-prone sites along the San Andreas Fault, they determined that quakes occurred at intervals ofapproximately 22 years near one site and concludedthat there was a 95 percent probability of an earthquake in that area by 1992.The earthquake did not occur within the time frame predicted, however.

Evidence against the kind of regular earthquakecycles that Lindh and Baker tried to establish has come from a relatively new field,paleoseismology. Paleoseismologists haveunearthed and dated geological features such as fault scarps that were causedby earthquakes thousands of years ago. They have determined that the average intervalbetween ten earthquakes that took place at one site along the San Andreas Faultin the past two millennia was 132 years, butindividual intervals ranged greatly, from 44 to 332 years.

(Book Question: 11)

The passage is primarily concerned with

A. explaining why onemethod of earthquake prediction has proven more practicable than an alternativemethod

B. suggesting that accurateearthquake forecasting must combine elements of long-term and short-termprediction

C. challenging the usefulness of dilatancytheory for explaining the occurrence of precursory phenomena      

D. discussing the deficiency of twomethods by which researchers have attempted to predict the occurrence ofearthquakes      

E. describing the development of methodsfor establishing patterns in the occurrence ofpast earthquakes

(Book Question: 12)

According to the passage, laboratoryevidence concerning the effects of stress on rocks mighthelp account for

A. differences in magnitudeamong earthquakes

B. certain phenomena that occur prior toearthquakes

C. variations in the intervals between earthquakes in a particular area

D. differences in the frequency with which earthquakes occur in various areas

E. the unreliability of short-termearthquake predictions

(Book Question: 13)

It can be inferred from the passage thatone problem with using precursory phenomena to predict earthquakes is thatminor tremors

A. typically occur some distance from the sites of the large earthquakes thatfollow them

B. are directly linked to the mechanisms thatcause earthquakes  mechanisms

C. are difficultto distinguish from major tremors

D. have proven difficultto measure accurately

E. are not always followed by large earthquakes

(Book Question: 14)

According to the passage, some researchers based their research about long-term earthquakeprediction on which of the following facts?

A. The historical record confirms that mostearthquakes have been preceded by minor tremors.

B. The average interval between earthquakesin one region of the San Andreas Fault is 132 years.

C. Some regions tend to be the site ofnumerous earthquakes over the course of many years.

D. Changes in the volume of rock can occuras a result of building stress and can lead to the weakening of rock.

E. Paleoseismologists have been able tounearth and date geological features caused by past earthquakes.

(Book Question: 15)

The passage suggests which of the followingabout the paleoseismologists’ findings described in lines 42–50?

A. They suggest that the frequency withwhich earthquakes occurred at a particular site decreasedsignificantly over the past two millennia.

B. They suggest that paleoseismologists maysomeday be able to make reasonably accuratelong-term earthquake predictions.

C. They suggest that researchers maysomeday be able to determine whichpast occurrences of minor tremors were actually followed by large earthquakes.

D. They suggest that the recurrence ofearthquakes in earthquake-prone sites is too irregular to serve as a basis forearthquake prediction.

E. They indicate that researchersattempting to develop long-term methods of earthquake prediction have overlooked important evidence concerning the causesof earthquakes.

(Book Question: 16)

The author implies which of the followingabout the ability of the researchers mentioned in line 18 to predictearthquakes?

A. They can identify when an earthquake islikely to occur but not how large it will be.

B. They can identify the regions whereearthquakes are likely to occur but not when they will occur.

C. They are unable to determine either thetime or the place that earthquakes are likely to occur.

D. They are likely to be more accurate atshort-term earthquake prediction than at long-term earthquake prediction.

E. They can determine the regions whereearthquakes have occurred in the past but not the regions where they are likelyto occur in the future.

答案：DBECDC

我想请教一下16题：

The author implies which of the followingabout the ability of the researchers mentioned in line 18 to predictearthquakes?

A. They can identify when an earthquake islikely to occur but not how large it will be.

B. They can identify the regions whereearthquakes are likely to occur but not when they will occur.

C. They are unable to determine either thetime or the place that earthquakes are likely to occur.

D. They are likely to be more accurate atshort-term earthquake prediction than at long-term earthquake prediction.

E. They can determine the regions whereearthquakes have occurred in the past but not the regions where they are likelyto occur in the future.

我错选了A，因为我理解的是第二段中说研究人员能预测出地震发生的时间，但无法预测出地震的震级大小

正确答案是C。能不能请NN们略微解释一下：原文中哪里暗示研究人员不能预测出地震发生的时间呢？谢谢！

adsdsd

OG解释 供参考：
Supporting idea
The question asks for information explicitly provided in the passage. The second paragraph indicates that researchers at first reported success in identifying earthquake precursors, but further analysis of the data undermined their theory. The passage then explains that atypical seismic waves were recorded before some earthquakes; this evidence at first seemed to support the researchers’ theory, before further analysis proved the evidence inadequate.

A   Although earthquakes are caused by stress on rock, the passage does not indicate that this fact encouraged researchers to believe that precursors could be used to predict earthquakes.
B   This fact would undermine the theory that changes in seismic waves are precursory phenomena that can be used to predict earthquakes.
C   Correct. Seismic waves with unusual velocities occurring before earthquakes at first seemed to provide support for researchers’ theory that earthquakes could be predicted by precursory phenomena.
D   Though earthquakes’ recurrence in certain regions is mentioned as being important to researchers seeking to make long-term earthquake predictions, it is not mentioned as being relevant to researchers’ theory that earthquakes can be predicted by precursory phenomena.
E   This is not mentioned as being relevant to scientists’ belief that earthquakes could be predicted on the basis of precursory phenomena.

yybinary

這題我也覺得解釋很奇怪。仔細閱讀覺得說整篇文章都不承認兩種方法能「正確」預測地震。選項a還是提到了能預測這個點，所以不對。通過排除只能選擇c

搬運工－http://gmatclub.com/forum/in-1971-researchers-hoping-to-predict-earthquakes-in-the-short-term-by-222825.html

Bradz

yybinary 发表于 2016-10-3 10:40
這題我也覺得解釋很奇怪。仔細閱讀覺得說整篇文章都不承認兩種方法能「正確」預測地震。選項a還是提到了能 ...

整片文章没有说不承认两种方法能‘正确’预测地震，而是指出了两种方法的不足（第11题问的就是这个，里面说的是deficiency）。

第一种方法其实可以预测地震的时间，但是由于不能预测地震的大小，就变得有deficiency。文章中' while thehistorical record confirms that most large earthquakes are preceded by minor tremors, these foreshocks indicate nothing aboutthe magnitude of an impending quake and are indistinguishable from other minortremors that occur without large earthquakes'，我的理解是大地震前的tremor和小地震前的tremor没区别，但是这和能够预测地震不矛盾，最多对采取何种防震措施有影响，因此才有deficient。

另外other minor tremors这里面的other指出了，minor tremors只能有两种结果，一是large earthquakes，二是without large quakes。如果问题里面是to predict large earthquakes，我就可以理解A不对，但是问题里面没有写large。
请指教。

猪小王

adsdsd 发表于 2016-9-14 03:10
OG解释 供参考：
Supporting idea
The question asks for information explicitly provided in the passage ...

说说我的理解。

这里是一个conditional reasoning. Researchers要做预测，想用的逻辑方法是：如果有possible precursors，就一定可以predict有earthquakes. If possible precursors are identified, then there will be an earthquakes after the precursors. 这里precursors是他们的evidence／antecedent，而earthquakes是result/consequence.


但是，通过analyze their data发现，these foreshacks ... are indistinguishable from other minortremors that occur without large earthquakes. 这句话告诉我们当precusors出现时，可能出现consequence, i.e., earthquakes, 但是也有情况是出现precusors却without large earthquakes. 说明researchers的条件推理不成立，invalid reasoning。


如果你选了A说明你认为They can identify when an earthquake is likely to occur。 这部分是错误的。有precursors但不一定有earthquakes，所以他们无法确定when。

CathyGYM

文中有一句话我不是非常明白：
Nothing that earthquakes tend to occur repeatedly in certain regions, Lindh and Baker attempted to identify patterns of recurrence, or earthquake cycles, on which to base predictions.
我的理解是：没有什么地震灾某个地区经常发生，L和B尝试发现地震的发生规律、周期，以此基础来预测地震。
可是这和14题选择C项有冲突

rachel556

CathyGYM 发表于 2017-6-8 16:03
文中有一句话我不是非常明白：
Nothing that earthquakes tend to occur repeatedly in certain regions, L ...

文中说的是 noting that 不是nothing 注意到地震在某个地区发生的频繁，... 这道题为什么选c我也不太确定...

CathyGYM

rachel556 发表于 2017-6-9 14:05
文中说的是 noting that 不是nothing 注意到地震在某个地区发生的频繁，... 这道题为什么选c我也不太确定 ...

哦哦对的 这样就可以解释14题为啥选C了
文中说“注意到地震经常发生在某些地区，L和B尝试去发现地震发生的规律或周期，作为预测的依据”
14题问：根据文章，一些研究人员根据他们的研究发现进行地震预测建立在哪个事实上？
C项，多年来，一些地区经常是许多地震的发源地，符合文中描述

778807

without large earthquakes可以有两种解释，一种是小地震，一种是没有地震。既然后面可能没有地震，那就不能预测地震发生的时间了。因为即使有tremor，也可能没地震。这个招就废了。

杀鸡杀鸡杀鸡007

我想问问14题的E选项有什么问题??