In spite of early doubts, it is now well established that large reserv

1. The passage suggests that the author would regard which of the following as most important for a "scientifically rigorous examination" (Highlighted) of the hypothesis that large reservoirs can induct earthquakes?

(A) Systematic surveys of seismic activity under a reservoir after filling began
This is not mentioned in the passage

(B) Detailed geological maps of the composition of rock strata underlying a reservoir
We know that even if composition of rock is the same, then also earthquakes may not be inducted hence this choice cannot hold

(C) Comparable records of seismic activity in the area of a reservoir prior to and after construction and filling of the reservoir
No such comparison is required to indicate the hypothesis

(D) Precise calculation of the amount of vertical pressure exerted by the reservoir's water load
Vertical pressure alone will not suffice as earthquake also depends on pore pressure

(E) Accurate records of the rate of increase in pore pressure in the rock strata underlying the reservoir
"Bursts of seismic activity are triggered when the water level changes, with the frequency of the activity increasing as the rate of level change increases." and "The water load exerts a simple vertical pressure on the rocks immediately, while the pore pressure in the rocks increases gradually as the water infiltrates at a rate that depends on their permeability and prior water content" indicate that the rate of change of water level impacts the earthquake. Since rate of fluctuation will depend on rate of infiltration which depends on the pore pressure

Ans E

2. According to the passage, earthquake activity in the area of the Nurek reservoir is most frequent when the

(A) reservoir is filled to capacity
Nothing is mentioned about what happens when reservoir is filled to capacity

(B) water level in the reservoir is exceptionally low
It depends on fluctuation but not necessarily on water level being low

(C) reservoir is subjected to sudden drops in temperature
Temperature is not discussed in passage

(D) water level in the reservoir fluctuates
"Bursts of seismic activity are triggered when the water level changes, with the frequency of the activity increasing as the rate of level change increases" answers this

(E) water level of the reservoir area behind the dam remains constant
This is exactly the opoosite of what is necessary. In fact, such regions are aseismic

Ans D

3. According to the passage, which of the following proves that earthquake activity in the area of the Nurek reservoir cannot be accounted for exclusively by the composition of the rock strata underlying the reservoir?

(A) There are two kinds of rock underlying the reservoir, but only the shallow-water limestones are permeable
No becaause behind the dam and upstream of dam have same composition but are still seismic/ asiesmic so this cannot be true

(B) The same rock strata underlie the whole reservoir area, but only one part of the area is subject to earthquake activity
"The answer lies in the varying structures of the rock strata and the different permcabilities such structures engender" indicates that structure is the reason and this choice basically addresses this poit that composition is not the reason

(C) The earthquake activity in the area is evenly distributed between the regions behind the dam and the central portion of the reservoir.
This is not true as per the passage: "The region containing that half of the reservoir immediately behind the dam, on the other hand, is almost completely aseismic"

(D) The vertical load exerted by the water in the reservoir has different effects on shallow-water limestones than on mixed shale and gypsum
This comparison has not been given in the passage

(E) When the frequency of earthquake activity increases, the locations of such activity become more diffuse
We have no info on what happens after frequency of earthquake increases

Ans B

4. Which of the following best describes the organization of the passage?

(A) An assertion is made, briefly explained, and then an illustrative example is examined in detail.
Assertion- it is now well established that large reservoirs can generate earthquakes, explanation - In general terms, what happens is that, Example - One such example

(B) A hypothesis is advanced, carefully qualified, and then supporting data are presented.
The hypothesis is not qualified anywhere in the passage rather it has been supported

(C) A scientific dispute is introduced and the casc for one side is analyzed and illustrated_
There is no dispute rather there was an earlier belief and a new belief which has been proven

('D) A generally accepted principle is stated in order to introduce a detailed examination of a case that violates the principle.
Generally accepted principle could be considered as the earlier belief but that was not vioilated. When it was introduced earlier, it was trated with skepticism but it was later proved using evidence

(E) A theory is explained and a recent example that makes the theory obsolete is presented.
Theory is not proven obsolete

Ans A

5. Which of the following sets of causes and effects most closely parallels reservoir-induced seismicity as it is described in the passage?

(A) Environmental stresses in an area combine to produce an effect; the introduction of an artifact to that area restructures the stresses and reduces the incidence of the effect.
There is no mention of combining stress

(B) An artifact is introduced into a stable environment; the environmental effects of that artifact cannot be separated from general environmental changes.
Nothing is mentioned on separation of effect of water level from the effect of rocks structure

(C) An artifact is introduced into an environment; local conditions peculiar to that environment have little impact on the effects generally produced by such artifacts.
Local conditions is referring to the structure of the rocks but that does not have little impact on effects prodcued by artifact

(D) An artifact creates certain initial effects on its environment; these environmental effects are gradually mitigated by environmental adaptation to the artifact.
Effects are not being mitigated hence this is wrong

(E) An artifact is introduced into an environment; the artifact generates spatially uniform stress but the environment responds differentially to that stress
Artifact- water level, This water level causes stress but because of the structure of rocks ( In general terms, what happens is that the huge mass of water in a reservoir changes the stress patterns in the underlying rocks.)
The rocks respond differently (The spatial distribution of the seismic activity at Nurek is less straightforward)

Ans E

6. Which of the following best describes the interaction of water and rock strata in the region of the anticline under the Nurek reservoir?

(A) Shale and gypsum form the top layer of rock in an anticline and thus the water cannot penetrate to the permeable limestone layer.
We know that water can penetrate deep in the strata so this choice seems to contradict by putting a restriction

(B) Fractured and highly permeable limestone forms a basin in an anticline through which water penetrates to the rock below.
The basin is present in syncline (Any water entering one of the permeable layers could migrate to the bottom of the basin formed by that layer) not anticline

(C) The shale and gypsum layer beneath the permeable limestone basin in an anticline prevents water from penetrating to deeper rock strata.
The passage says the water can penetrate deep in the rock strata

(D) The shape of an anticline allows water to travel along the permeable layer and penetrate into deep rock strata.
"In this region water entering a permeable layer can diffuse along it and thus be carried to various depths without restriction" proves this

(E) The structure of limestone strata alternating with shale and gypsum strata in an anticline allows the region to collect and hold water, thus increasing the load on the rocks below
We have no idea on how exactly the rocks are allocated in an anticline

Ans D

7. It can be inferred from the passage that an accurate prediction of reservoir-induced earthquake activity at the site of the Nurek reservoir prior to its construction would have required all of the following data EXCEPT

(A) a general geological survey of the area, establishing the lithological composition of the rock strata
"Any water entering one of the permeable layers could migrate to the bottom of the basin formed by that layer" indicates that water flow is impacted by the lithiological composition which in turn impacts earthquake activity

(B) a detailed examination of the structure of the rock strata underlying the site of the reservoir
"The answer lies in the varying structures of the rock strata " indicates this

(C) a projection of the number and magnitude of the fluctuations in the level of the water in the reservoir
"Bursts of seismic activity are triggered when the water level changes, with the frequency of the activity increasing as the rate of level change increases" indicates this

(D) an estimate of the load that would be created by the total mass of water in the reservoir
"huge mass of water in a reservoir changes the stress patterns " indicates this

(E) a determination of the chemical properties of the water that would be used to fill the reservoir
Nothing has been mentioned about chemical properties

Ans E

8. The passage implies that which of the following would be true in the area of the Nurek reservoir if the rate of change in the water level in the reservoir were very gradual?

(A) Stress patterns in the rock strata beneath the reservoir would be the same as before its construction
This is too strong a claim and cannot be inferred given that fluctuation does cause stress as per passage

(B) The seismic activity beneath the reservoir would not be very frequent
Yes because passage says "the frequency of the activity increasing as the rate of level change increases" so this implies activity is not frequent in change is slower

(C) The spatial distribution of seismic activity beneath the reservoir would be altered.
We dont know the relation b/w gradual change and spatial distribution

(D) The rate of infiltration into rock strata below the reservoir would increase
Rate of infiltration depends on permeability and existing water content in rocks not on the rate of change in water level

(E) The stress patterns in the rocks under-lying the reservoir would be less affected by vertical load.

Ans B

9. The author of the passage is primarily concerned with

(A) advancing a theory-
This is tempting however the purpose is not to just put forward a theory but mainly to explain in detail the theory

(B) resolving a dispute-
There is no dispute being discussed in the passage - just an old opinion and a new one

(C) explaining a relationship-
Yes relationship is being explained "reservoirs can generate earthquakes" through all paras. First para is talking about doubts in an earlier belief, second para briefly explains the theory, and the rest of the passage gives an example to explain the theory in detail

(D) correcting an oversimplification-
There was nothing complicated and it did not need any correction. Only a new relationship is being elaborated on

(E) reinterpreting data-
No prior info on any data is provided

Ans C

1. The passage suggests that the author would regard which of the following as most important for a "scientifically rigorous examination" (Highlighted) of the hypothesis that large reservoirs can induce earthquakes?
The author mentions in the first paragraph that “When the possibility of reservoir-induced seismicity was first suggested during the mid-1960s, it was greeted with skepticism in some quarters, largely because detailed records of the pre-reservoir seismic background were incomplete at best. A scientifically rigorous examination of the evidence was therefore impossible.”
This suggests that the detailed records of pre-reservoir seismic data is critical for carrying out a scientifically rigorous examination. Therefore, option C is correct.

(A) Systematic surveys of seismic activity under a reservoir after filling began
Option A is incorrect because this data can be obtained later but records of seismic data pre-reservoir is required for proper analysis.

(B) Detailed geological maps of the composition of rock strata underlying a reservoir
Not true as the details of geological maps can be obtained later.

(C) Comparable records of seismic activity in the area of a reservoir prior to and after construction and filling of the reservoir
Correct as explained above.

(D) Precise calculation of the amount of vertical pressure exerted by the reservoir's water load
Option D is incorrect because the author has not mentioned that precise calculation of amount of vertical pressure is critical for a thorough scientific examination.

(E) Accurate records of the rate of increase in pore pressure in the rock strata underlying the reservoir
Option E is incorrect because the author has not mentioned that accurate records of the rate of increase in pore pressure in the rock strata underlying the reservoir is critical for a thorough scientific examination.

2. According to the passage, earthquake activity in the area of the Nurek reservoir is most frequent when the
From the lines “In this case, the timing of the induced seismicity is directly related not to the absolute amount of water present but to variations in that amount. Bursts of seismic activity are triggered when the water level changes, with the frequency of the activity increasing as the rate of level change increases” we can infer that the fluctuation of water level in the reservoir causes earthquake activity. Option D is correct.

(A) reservoir is filled to capacity
Not true because the passage mentions that “Bursts of seismic activity are triggered when the water level changes, with the frequency of the activity increasing as the rate of level change increases”

(B) water level in the reservoir is exceptionally low
Option B is incorrect because low water level is not mentioned as a reason for earthquake activity.

(C) reservoir is subjected to sudden drops in temperature
Not true as no such support is given in the passage.

(D) water level in the reservoir fluctuates
Correct as explained above.

(E) water level of the reservoir area behind the dam remains constant
Option E is incorrect because no such support is given in the passage.

3. According to the passage, which of the following proves that earthquake activity in the area of the Nurek reservoir cannot be accounted for exclusively by the composition of the rock strata underlying the reservoir?
The passage mentions that both the seismic and aseismic zones in the area of the Nurek reservoir are lithologically similar. Also, the reason for the location of the induced seismicity is due to the varying structures of the rock strata and the different permeabilities such structures engender.
From this we can infer that Option B is correct.
(A) There are two kinds of rock underlying the reservoir, but only the shallow-water limestones are permeable.
Option A is incorrect because the passage mentions that it is the varying structures of the rock strata and the different permeabilities such structures engender which induces seismic activity.

(B) The same rock strata underlie the whole reservoir area, but only one part of the area is subject to earthquake activity.
Correct as explained above.

(C) The earthquake activity in the area is evenly distributed between the regions behind the dam and the central portion of the reservoir.
Option C is incorrect because the passage mentions that earthquake activity is not evenly distributed.

(D) The vertical load exerted by the water in the reservoir has different effects on shallow-water limestones than on mixed shale and gypsum
Option D is incorrect because the passage mentions that it is the varying structures of the rock strata and the different permeabilities such structures engender which induces seismic activity.
(E) When the frequency of earthquake activity increases, the locations of such activity become more diffuse.
Option E is incorrect because the passage mentions that it is the varying structures of the rock strata and the different permeabilities such structures engender which induces seismic activity.

5. Which of the following sets of causes and effects most closely parallels reservoir-induced seismicity as it is described in the passage?
from the passage we find that - The water load exerts a simple vertical pressure on the rocks immediately, while the pore pressure in the rocks increases gradually as the water infiltrates at a rate that depends on their permeability and prior water content. In favorable conditions, there is induced seismic activity in that region. The variations in water level causes changes in seismic activity timings.
The pattern follows that of Option E.
(E) An artifact is introduced into an environment; the artifact generates spatially uniform stress but the environment responds differentially to that stress.

6. Which of the following best describes the interaction of water and rock strata in the region of the anticline under the Nurek reservoir?
The strata are folded into an inverted V-shape (anticline). In this region water entering a permeable layer(shallow-water limestones) can diffuse along it and thus be carried to various depths without restriction. Here the pore pressure at given depths does change when the water level fluctuates, and this is sufficient to generate seismicity.
From this we can infer that Option D is correct.

8. The passage implies that which of the following would be true in the area of the Nurek reservoir if the rate of change in the water level in the reservoir were very gradual?

In this case, the timing of the induced seismicity is directly related not to the absolute amount of water present but to variations in that amount (level of water). Bursts of seismic activity are triggered when the water level changes, with the frequency of the activity increasing as the rate of level change increases.
Since the timing of seismic activity is affected by the changes in water level Option B is correct in case if the changes were very gradual.

1. The passage suggests that the author would regard which of the following as most important for a "scientifically rigorous examination" (Highlighted) of the hypothesis that large reservoirs can induct earthquakes?

Refer to the line "When the possibility of reservoir-induced seismicity was first suggested during the mid-1960s, it was greeted with skepticism in some quarters, largely because detailed records of the pre-reservoir seismic background were incomplete at best." This suggest that before the construction of the reservoir, data set was not complete about the seismic activity level in that particular area. If the area where reservoir is made is already seismic, than creating a reservoir in that area may possibly not be reason for seismic activity.

(A) Systematic surveys of seismic activity under a reservoir after filling began

(B) Detailed geological maps of the composition of rock strata underlying a reservoir

(C) Comparable records of seismic activity in the area of a reservoir prior to and after construction and filling of the reservoir ~ Correct, as explained above.

(D) Precise calculation of the amount of vertical pressure exerted by the reservoir's water load ~

(E) Accurate records of the rate of increase in pore pressure in the rock strata underlying the reservoir

2. According to the passage, earthquake activity in the area of the Nurek reservoir is most frequent when the

(A) reservoir is filled to capacity ~ Incorrect, not mentioned.

(B) water level in the reservoir is exceptionally low ~ Incorrect, not mentioned.

(C) reservoir is subjected to sudden drops in temperature ~ Incorrect, not mentioned.

(D) water level in the reservoir fluctuates ~ Correct, refer to the line "Bursts of seismic activity are triggered when the water level changes, with the frequency of the activity increasing as the rate of level change increases." It is the change in water level that causes the seismic activity.

(E) water level of the reservoir area behind the dam remains constant ~ Incorrect, not mentioned.

3. According to the passage, which of the following proves that earthquake activity in the area of the Nurek reservoir cannot be accounted for exclusively by the composition of the rock strata underlying the reservoir?


(A) There are two kinds of rock underlying the reservoir, but only the shallow-water limestones are permeable. ~ Incorrect, refer to the line "Yet both the seismic and aseismic zones are lithologically similar, consisting largely of shallow-water limestones, which are highly fractured and thus relatively permeable, interbedded with mixed components of low-permeability shale and gypsum."

(B) The same rock strata underlie the whole reservoir area, but only one part of the area is subject to earthquake activity. ~ Correct, refer to the line "Most of the induced earthquakes occur beneath the central part of the reservoir and upstream from it. The region containing that half of the reservoir immediately behind the dam, on the other hand, is almost completely aseismic. Yet both the seismic and aseismic zones arc lithologically similar, consisting largely of shallow-water limestones, which are highly fractured and thus relatively permeable, interbedded with mixed components of low-permeability shale and gypsum."

(C) The earthquake activity in the area is evenly distributed between the regions behind the dam and the central portion of the reservoir. ~ Incorrect, refer to the line "Most of the induced earthquakes occur beneath the central part of the reservoir and upstream from it. The region containing that half of the reservoir immediately behind the dam, on the other hand, is almost completely aseismic" the seismic activity is not evenly distributed.

(D) The vertical load exerted by the water in the reservoir has different effects on shallow-water limestones than on mixed shale and gypsum ~ Incorrect, this is not mentioned that it has different effect on shallow water limestones and mixed shale and gypsum.

(E) When the frequency of earthquake activity increases, the locations of such activity become more diffuse. ~ Incorrect, the seismic activity does not diffuse and stick to the the initial place. Refer to the line "Most of the induced earthquakes occur beneath the central part of the reservoir and upstream from it. The region containing that half of the reservoir immediately behind the dam, on the other hand, is almost completely aseismic."


4. Which of the following best describes the organization of the passage?

(A) An assertion is made, briefly explained, and then an illustrative example is examined in detail. ~ In Correct, Author begins the passage by " In spite of early doubts, it is now well established that large reservoirs can generate earthquakes." He is making a hypothesis why that fact it is well established. The assertion is explained with the example of "Nurek reservoir" in detail, but Nurek Reservoir is not highlighted author want to prove the hypothesis by presenting the supporting data why it is correct.

(B) A hypothesis is advanced, carefully qualified, and then supporting data are presented. ~ Correct, Author begins the passage by " In spite of early doubts, it is now well established that large reservoirs can generate earthquakes." He is making a hypothesis why that fact it is well established. The assertion is explained with the example of "Nurek reservoir" in detail, but Nurek Reservoir is not highlighted author want to prove the hypothesis by presenting the supporting data why it is correct.

(C) A scientific dispute is introduced and the case for one side is analyzed and illustrated ~ Incorrect, author does not take any side, in the passage only one side is presented, author establish the fact in the first line itself, that in spite of early doubts it is well established that large reservoirs can generate earthquakes.

('D) A generally accepted principle is stated in order to introduce a detailed examination of a case that violates the principle. ~ Incorrect, author does not mention that it violates the principle, he is just finding the reason for "What, then, governs the location of the induced seismicity?"

(E) A theory is explained and a recent example that makes the theory obsolete is presented. ~ Incorrect, author does not mention that the theory is obsolete.


5. Which of the following sets of causes and effects most closely parallels reservoir-induced seismicity as it is described in the passage?


(A) Environmental stresses in an area combine to produce an effect; the introduction of an artifact to that area restructures the stresses and reduces the incidence of the effect. ~ Incorrect, it does not reduce the incidence of the effect.

(B) An artifact is introduced into a stable environment; the environmental effects of that artifact cannot be separated from general environmental changes. ~ Correct, it is the reservoir which causes the seismic activity and both cannot be seperated.

(C) An artifact is introduced into an environment; local conditions peculiar to that environment have little impact on the effects generally produced by such artifacts. ~ Incorrect, local conditions affect the artificat refer to the line "The answer lies in the varying structures of the rock strata and the different permcabilities such structures engender".

(D) An artifact creates certain initial effects on its environment; these environmental effects are gradually mitigated by environmental adaptation to the artifact. ~ Incorrect, we don't know that these effects will be mitigated in future.

(E) An artifact is introduced into an environment; the artifact generates spatially uniform stress but the environment responds differentially to that stress. ~ Incorrect, the stress is not uniform, refer to the line "Here the pore pressure at given depths does change when the water level fluctuates,"

6. Which of the following best describes the interaction of water and rock strata in the region of the anticline under the Nurek reservoir?


(A) Shale and gypsum form the top layer of rock in an anticline and thus the water cannot penetrate to the permeable limestone layer. ~ Incorrect, water can penetrate without restriction refer to the line "In this region water entering a permeable layer can diffuse along it and thus be carried to various depths without restriction."

(B) Fractured and highly permeable limestone forms a basin in an anticline through which water penetrates to the rock below. ~ Incorrect, refer to the line "Yet both the seismic and aseismic zones arc lithologically similar, consisting largely of shallow-water limestones, which are highly fractured and thus relatively permeable" It is not the limestone which is the correct reason.

(C) The shale and gypsum layer beneath the permeable limestone basin in an anticline prevents water from penetrating to deeper rock strata. ~ Incorrect, this is true for syncline.

(D) The shape of an anticline allows water to travel along the permeable layer and penetrate into deep rock strata. ~Correct refer to the line "In this region water entering a permeable layer can diffuse along it and thus be carried to various depths without restriction." So unlike syncline where water cannot penetrate into deeper rock strata, in this type water can reach deeper without restrictions.

(E) The structure of limestone strata alternating with shale and gypsum strata in an anticline allows the region to collect and hold water, thus increasing the load on the rocks below. ~ Incorrect, this does not resulting in holding of water, instead due to fluctuating water level sesmicity arises.

7. It can be inferred from the passage that an accurate prediction of reservoir-induced earthquake activity at the site of the Nurek reservoir prior to its construction would have required all of the following data EXCEPT


(A) a general geological survey of the area, establishing the lithological composition of the rock strata "Incorrect, refer to the line "The answer lies in the varying structures of the rock strata and the different permcabilities such structures engender."

(B) a detailed examination of the structure of the rock strata underlying the site of the reservoir ~ Incorrect, refer to the line "The answer lies in the varying structures of the rock strata and the different permcabilities such structures engender."

(C) a projection of the number and magnitude of the fluctuations in the level of the water in the reservoir " InCorrect, refer to the line "Bursts of seismic activity are triggered when the water level changes, with the frequency of the activity increasing as the rate of level change increases."

(D) an estimate of the load that would be created by the total mass of water in the reservoir ~ InCorrect, refer to the line "The water load exerts a simple vertical pressure on the rocks immediately, while the pore pressure in the rocks increases gradually as the water infiltrates at a rate that depends on their permeability and prior water content.".

(E) a determination of the chemical properties of the water that would be used to fill the reservoir ~ Correct, not mentioned in the pasage.

8. The passage implies that which of the following would be true in the area of the Nurek reservoir if the rate of change in the water level in the reservoir were very gradual?

(A) Stress patterns in the rock strata beneath the reservoir would be the same as before its construction.

(B) The seismic activity beneath the reservoir would not be very frequent. ~ "Correct, refer to the line "Bursts of seismic activity are triggered when the water level changes, with the frequency of the activity increasing as the rate of level change increases."

(C) The spatial distribution of seismic activity beneath the reservoir would be altered.

(D) The rate of infiltration into rock strata below the reservoir would increase.

(E) The stress patterns in the rocks under-lying the reservoir would be less affected by vertical load.

9. The author of the passage is primarily concerned with

(A) advancing a theory

(B) resolving a dispute

(C) explaining a relationship

(D) correcting an oversimplification ~ Correct, author is trying to answer the question "What, then, governs the location of the induced seismicity?" about an established fact, that large reservoirs can generate earthquakes. He is correcting the oversimplification explaining the seismic activity at Nurek

(E) reinterpreting data

Hello Everyone!

OAs to the passage are revealed. Official Explanation is also posted.

Elite097 is on top here
pintukr is at second position
sivakumarm786 is at third position.

Everybody please format your responses properly.

There are mistakes in the passage ("largely bemuse detailed records of the pm-reservoir seismic background were incomplete at best.")

Thank you!

Fixed the typos.

Hello experts

can you explain to me why B is not correct in Q4 ?

Thanks

Detailed explanation of each question is posted already you just need to find it.

Good luck!