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

Question

In spite of early doubts, it is now well established that large reservoirs can generate earthquakes. 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 prereservoir seismic background were incomplete at best. A  scientifically rigorous examination  of the evidence was therefore impossible.

But now there are no doubts, for well-documented examples of reservoir-induced seismicity are known throughout the inhabited continents. In general terms, what happens is that the huge mass of water in a reservoir changes the stress patterns in the underlying rocks. 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.

One such example is the Nurek reservoir in the Soviet Union, which has been generating seismic activity since filling began in the early 1970's. 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.

The spatial distribution of the seismic activity at Nurek is less straightforward. 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. What, then, governs the location of the induced seismicity?

The answer lies in the varying structures of the rock strata and the different permcabilities such structures engender. Immediately upstream from the dam the alternating layers of limestone- and gypsum-shale arc folded into a V-shape (syncline). Any water entering one of the permeable layers could migrate to the bottom of the basin formed by that layer, but would be prevented from moving any further downward by the impermeable rock layer beneath. In this region, therefore, water cannot enter the vast mass of rock below and cannot thereby change the port pressure. The water in the reservoir here acts only as a load and thus is insufficient to induce seismicity.

Further upstream from the darn, on the other-hand, the strata arc folded into an inverted V-shape (anticline). In this region water entering a permeable layer 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.    1 
 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
(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
(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 
 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
(B) water level in the reservoir is exceptionally low
(C) reservoir is subjected to sudden drops in temperature
(D) water level in the reservoir fluctuates
(E) water level of the reservoir area behind the dam remains constant

3 
 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.
(B) The same rock strata underlie the whole reservoir area, but only one part of the area is subject to earthquake activity.
(C) The earthquake activity in the area is evenly distributed between the regions behind the dam and the central portion of the reservoir.
(D) The vertical load exerted by the water in the reservoir has different effects on shallow-water limestones than on mixed shale and gypsum_
(E) When the frequency of earthquake activity increases, the locations of such activity become more diffuse.

4 
 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.
(B) A hypothesis is advanced, carefully qualified, and then supporting data are presented.
(C) A scientific dispute is introduced and the c:asc for one side is analyzed and illustrated_
('D) A generally accepted principle is stated in order to introduce a detailed examination of a case that violates the principle.
(E) A theory is explained and a recent example that makes the theory obsolete is presented.

5 
 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.
(B) An artifact is introduced into a stable environment; the environmental effects of that artifact cannot be separated from general environmental changes.
(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.
(D) An artifact creates certain initial effects on its environment; these environmental effects are gradually mitigated by environmental adaptation to the artifact.
(E) An artifact is introduced into an environment; the artifact generates spatially uniform stress but the environment responds differentially to that stress.

6 
 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.
(B) Fractured and highly permeable limestone forms a basin in an anticline through which water penetrates to the rock below.
(C) The shale and gypsum layer beneath the permeable limestone basin in an anticline prevents water from penetrating to deeper rock strata. 
(D) The shape of an anticline allows water to travel along the permeable layer and penetrate into deep rock strata.
(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.

7 
 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
(B) a detailed examination of the structure of the rock strata underlying the site of the reservoir
(C) a projection of the number and magnitude of the fluctuations in the level of the water in the reservoir
(D) an estimate of the load that would be created by the total mass of water in the reservoir
(E) a determination of the chemical properties of the water that would be used to fill the reservoir

8 
 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.
(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 
 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
(E) reinterpreting data

Oppenheimer1945 · Answer

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 (True) 
 what happens is that the huge mass of water in a reservoir changes the stress patterns in the underlying rocks.

(B) Detailed geological maps of the composition of rock strata underlying a reservoir
- this is not specific to impact of reservoirs on earthquake
(C) Comparable records of seismic activity in the area of a reservoir prior to and after construction and filling of the reservoir-
Intersting but not suggested in passage
(D) Precise calculation of the amount of vertical pressure exerted by the reservoir's water load 
- water cannot enter the vast mass of rock below and cannot thereby change the port pressure. 
(E) Accurate records of the rate of increase in pore pressure in the rock strata underlying the reservoir
-the pore pressure at given depths does change when the water level fluctuates, and this is sufficient to generate seismicity.(change in pore pressure is important and not increase in pressure)

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
(B) water level in the reservoir is exceptionally low
(C) reservoir is subjected to sudden drops in temperature
 (D) water level in the reservoir fluctuates (True) 
(E) water level of the reservoir area behind the dam remains constant

Nurek reservoir in the Soviet Union, which has been generating seismic activity since filling began in the early 1970's. 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.

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.
(B) The same rock strata underlie the whole reservoir area, but only one part of the area is subject to earthquake activity.
 (C) The earthquake activity in the area is evenly distributed between the regions behind the dam and the central portion of the reservoir.(True) 
(D) The vertical load exerted by the water in the reservoir has different effects on shallow-water limestones than on mixed shale and gypsum_
(E) When the frequency of earthquake activity increases, the locations of such activity become more diffuse.

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. What, then, governs the location of the induced seismicity?

The answer lies in the varying structures of the rock strata and the different permcabilities such structures engender. Immediately upstream from the dam the alternating layers of limestone- and gypsum-shale arc folded into a V-shape (syncline). Further upstream from the darn, on the other-hand, the strata arc folded into an inverted V-shape (anticline)

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. (This is the right flow)
(B) A hypothesis is advanced, carefully qualified, and then supporting data are presented. (no data is presented)
(C) A scientific dispute is introduced and the c:asc for one side is analyzed and illustrated_ (case for one side is not presented)
 (D) A generally accepted principle is stated in order to introduce a detailed examination of a case that violates the principle  
   In general terms, what happens is that the huge mass of water in a reservoir changes the stress patterns in the underlying rocks . 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.

One such example is the Nurek reservoir in the Soviet Union, which has been generating seismic activity since filling began in the early 1970's. 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.

(E) A theory is explained and a recent example that makes the theory obsolete is presented. (example of Nurek doesn't make the theory 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. (stresses in an area combine is wrong)
 (B) An artifact is introduced into a stable environment; the environmental effects of that artifact cannot be separated from general environmental changes.(the reservoir is built, the effects of earthquake becomes a normal phenomena) - True  
(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 do have impact )
(D) An artifact creates certain initial effects on its environment; these environmental effects are gradually mitigated by environmental adaptation to the artifact.
(Mitigation is not dicussed in passage)
(E) An artifact is introduced into an environment; the artifact generates spatially uniform stress but the environment responds differentially to that stress.
(env responding diff is not correct)

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.
(B) Fractured and highly permeable limestone forms a basin in an anticline through which water penetrates to the rock below.
(C) The shale and gypsum layer beneath the permeable limestone basin in an anticline prevents water from penetrating to deeper rock strata.
 (D) The shape of an anticline allows water to travel along the permeable layer and penetrate into deep rock strata. (True) 
(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.

shallow-water limestones, which are highly fractured and thus relatively permeable, interbedded with mixed components of low-permeability shale and gypsum. the strata arc folded into an inverted V-shape (anticline). In this region water entering a permeable layer can diffuse along it and thus be carried to various depths without restriction

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
(B) a detailed examination of the structure of the rock strata underlying the site of the reservoir
(C) a projection of the number and magnitude of the fluctuations in the level of the water in the reservoir
(D) an estimate of the load that would be created by the total mass of water in the reservoir
 (E) a determination of the chemical properties of the water that would be used to fill the reservoir (This is not given in the passage)

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. (True) 
(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.

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.

9. The author of the passage is primarily concerned with

(A) advancing a theory (author puts efforts to explain the cause )
 (B) resolving a dispute (Author clarifies the true reason for seismic activity is change in water level and not the huge mass of reservoir exerting pressure in rocks ) 
(C) explaining a relationship (this is the part of passage)
(D) correcting an oversimplification (no correction is posed by the author)
(E) reinterpreting data (no data is reinterpretter here)

pintukr · Answer

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
 surveys will only reflect past trends; evidence for rigorous examination is sought

(B) Detailed geological maps of the composition of rock strata underlying a reservoir
  provides requisite evidence (as mentioned in paragraphs 4 and 5)..CORRECT answer

(C) Comparable records of seismic activity in the area of a reservoir prior to and after construction and filling of the reservoir
 only highlights the effect of reservoir..no evidence presented

(D) Precise calculation of the amount of vertical pressure exerted by the reservoir's water load
 water load may not be the sole criterion..rate of water level changes can also be a factor for earthquakes

(E) Accurate records of the rate of increase in pore pressure in the rock strata underlying the reservoir
 only one of the constituents/factors..better evidence is the composition of rock strata

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
 variations in the amount of filled water --as highlighted in paragraph 3

(B) water level in the reservoir is exceptionally low
 As highlighted in paragraph 3, the variations in the amount of filled water is the criterion

(C) reservoir is subjected to sudden drops in temperature
 Irrelevant prompt

(D) water level in the reservoir fluctuates
  Paragraph 3 (lines 4to 6) highlight that ----the timing of the induced seismicity is directly related not to the absolute amount of water present but to variations in that amount..CORRECT answer /color]

(E) water level of the reservoir area behind the dam remains constant
 Out of scope answer

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.
 kinds of rocks in the Nurek reservoir doesn't account for the earthquake activity

(B) The same rock strata underlie the whole reservoir area, but only one part of the area is subject to earthquake activity.
  as highlighted in paragraphs 4 and 5 , it has been shown that 'the different permcabilities such structures engender' leading to 'syncline' and 'anticline' are the contributing factors for earthquakes..CORRECT answer

(C) The earthquake activity in the area is evenly distributed between the regions behind the dam and the central portion of the reservoir.
 Incorrect vis-a-vis facts presented in the passage

(D) The vertical load exerted by the water in the reservoir has different effects on shallow-water limestones than on mixed shale and gypsum_
 no such facts regarding vertical load variations can be deduced

(E) When the frequency of earthquake activity increases, the locations of such activity become more diffuse.
 Out of scope prompt 
 
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.
  Para 1 (An assertion is made), Para 2(briefly explained), Para3,4,5 ( and then an illustrative example is examined in detail)..CORRECT answer  
.
(B) A hypothesis is advanced, carefully qualified, and then supporting data are presented.
 No qualification of hypothesis can be observed in the passage

(C) A scientific dispute is introduced and the case for one side is analyzed and illustrated_
 Out of scope, as no scientific dispute has been presented

('D) A generally accepted principle is stated in order to introduce a detailed examination of a case that violates the principle.
 'Acceptance' can't be ascertained

(E) A theory is explained and a recent example that makes the theory obsolete is presented.
 theory has not been presented as '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.
 combination of environmental stresses not presented in the passage

(B) An artifact is introduced into a stable environment; the environmental effects of that artifact cannot be separated from general environmental changes.
 Out of scope prompt

(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.
 opposite to this is true, as local environment have considerable impact on the effects

(D) An artifact creates certain initial effects on its environment; these environmental effects are gradually mitigated by environmental adaptation to the artifact.
 'mitigation' of effects is contrary to the ideas presented in the passage

(E) An artifact is introduced into an environment; the artifact generates spatially uniform stress but the environment responds differentially to that stress.
  formation of 'syncline' and 'anticline' pertaining to the rock strata..is akin to different environmental responses..CORRECT answer

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.
 in fact water can penetrate..correct facts not presented in this prompt

(B) Fractured and highly permeable limestone forms a basin in an anticline through which water penetrates to the rock below.
 'basin formation' -- can't be deduced using the facts in the passage

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

(D) The shape of an anticline allows water to travel along the permeable layer and penetrate into deep rock strata.
  anticline (opposite to V-shape) assists in water travelling along permeable layers, further leading to earthquakes..CORRECT answer

(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.
 in fact, the permeablity of rock layers is the factor leading to earthquakes during the interaction of water and rock strata in the region of the anticline

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
 listed as an evidence (paragraph 1)

(B) a detailed examination of the structure of the rock strata underlying the site of the reservoir
 similarly, listed as an evidence (paragraph 1)

(C) a projection of the number and magnitude of the fluctuations in the level of the water in the reservoir
 listed as an evidence (paragraph 3)

(D) an estimate of the load that would be created by the total mass of water in the reservoir
 listed as an evidence (paragraphs 3 and 4)

(E) a determination of the chemical properties of the water that would be used to fill the reservoir
  not listed as an evidence for examination..hence, CORRECT answer

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.
 no such deductions can be made (using facts presented in paragraphs 3 and 4)

(B) The seismic activity beneath the reservoir would not be very frequent.
  Lines 7-9 (Paragraph 3) allude to this deduction...CORRECT answer /color]

(C) The spatial distribution of seismic activity beneath the reservoir would be altered.
 no discussions in the relevant paragraphs relating to the alterations in spatial distribution

(D) The rate of infiltration into rock strata below the reservoir would increase.
 rate of infiltration is only dependent on the permeability of rocks

(E) The stress patterns in the rocks under-lying the reservoir would be less affected by vertical load.
 no such cause and effect highlighted in the passage

9. The author of the passage is primarily concerned with

(A) advancing a theory
  theory of reservoirs leading to seismic activity has been presented in the passage...CORRECT answer

(B) resolving a dispute
 no dispute of views presented in the passage

(C) explaining a relationship
 Out of scope prompt

(D) correcting an oversimplification
 Irrelevant , as the focus of the passage is explaining the theory of reservoirs leading to seismic activity

(E) reinterpreting data
 no data analysis aspects dealt with in the passage

IMO, the correct answer sequence should be BDBAEDEBA

Elite097 · Answer

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

$!vakumar.m · Answer

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.

Catman · Answer

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

Sajjad1994 · Answer

Explanation

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?

Explanation

The passage discusses how early doubts about whether large reservoirs could generate earthquakes have been dispelled by well-documented examples of reservoir-induced seismicity. The author suggests that a  "scientifically rigorous examination"  of this hypothesis was not possible in the mid-1960s because detailed records of pre-reservoir seismic activity were incomplete. The passage then goes on to describe how the mass of water in a reservoir changes stress patterns in underlying rocks and how the location of induced seismicity is related to the structures of rock strata and their permeabilities.

Based on this information, the author would likely regard comparable records of seismic activity in the area of a reservoir prior to and after construction and filling of the reservoir as most important for a  "scientifically rigorous examination"  of the hypothesis. This is because such records would allow for a direct comparison of seismic activity before and after the reservoir was built, providing stronger evidence for or against the hypothesis. Therefore, the correct answer is  (C) .

Option (A)  suggests systematic surveys of seismic activity after filling began, which could provide useful data but would not allow for a direct comparison of seismic activity before and after construction.

Option (B)  suggests detailed geological maps, which could also be useful but are not directly related to the examination of the hypothesis in question.

Option (D)  suggests precise calculation of the amount of vertical pressure exerted by the reservoir's water load, which is mentioned in the passage but is not presented as a crucial factor in examining the hypothesis.

Option (E)  suggests accurate records of the rate of increase in pore pressure, which is mentioned in the passage as a factor in inducing seismicity, but again is not presented as crucial to a  "scientifically rigorous examination"  of the hypothesis.

Answer: C

Sajjad1994 · Answer

Explanation

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

Explanation

The passage discusses the phenomenon of reservoir-induced seismicity and how the Nurek reservoir in the Soviet Union generates seismic activity. The passage states 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. Therefore, the correct answer is  (D)  water level in the reservoir fluctuates.

Option (A)  is incorrect because the passage does not mention that earthquake activity is most frequent when the reservoir is filled to capacity.

Option (B)  is incorrect because the passage does not mention that earthquake activity is most frequent when the water level in the reservoir is exceptionally low.

Option (C)  is incorrect because the passage does not mention that the reservoir is subjected to sudden drops in temperature.

Option (E)  is incorrect because the passage states that the region containing half of the reservoir immediately behind the dam is almost completely aseismic, regardless of the water level.

Answer: D

Sajjad1994 · Answer

Explanation

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?

Explanation

The correct answer to this question is  (B)  The same rock strata underlie the whole reservoir area, but only one part of the area is subject to earthquake activity.

The passage states that the lithology (composition of rock) of the seismic and aseismic zones at Nurek are similar, consisting of shallow-water limestones interbedded with mixed components of low-permeability shale and gypsum. The passage also explains that the location of the induced seismicity is governed by the varying structures of the rock strata and their permeabilities. Specifically, the region containing half of the reservoir immediately behind the dam is almost completely aseismic because the alternating layers of limestone and shale-gypsum are folded into a V-shape, preventing water from entering the vast mass of rock below and changing the pore pressure. However, further upstream from the dam, where the strata are folded into an inverted V-shape, water can diffuse along permeable layers and change the pore pressure, thus generating seismicity.

Therefore,  (B)  is the correct answer because it explains that the same rock strata underlie the whole reservoir area, but only one part of the area is subject to earthquake activity, which implies that the composition of the rock strata alone cannot account for earthquake activity in the area.

Answer: B

Sajjad1994 · Answer

Explanation

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

Explanation

The organization of the passage can be described as follows:

The passage begins by discussing how early doubts about the possibility of reservoir-induced seismicity were due to incomplete records of pre-reservoir seismic background. The passage then goes on to explain how this skepticism is now unwarranted, given that well-documented examples of reservoir-induced seismicity are known throughout the inhabited continents. The passage then provides an example of reservoir-induced seismicity in the Nurek reservoir in the Soviet Union, explaining how the timing and spatial distribution of seismic activity there are related to variations in the amount of water in the reservoir and the permeability of the rock strata.

Therefore, the best answer is  (A) : An assertion is made, briefly explained, and then an illustrative example is examined in detail.

Answer: A

Sajjad1994 · Answer

Explanation

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

Explanation

The passage describes how large reservoirs can generate earthquakes, as the huge mass of water in a reservoir changes the stress patterns in the underlying rocks. 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. The Nurek reservoir in the Soviet Union has been generating seismic activity since filling began in the early 1970s, and 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. The spatial distribution of the seismic activity at Nurek is less straightforward, with most of the induced earthquakes occurring beneath the central part of the reservoir and upstream from it.

The question asks us to identify the set of causes and effects that most closely parallels reservoir-induced seismicity as described in the passage. None of the answer choices directly addresses this phenomenon, but option  (E)  is the closest match. It states that an artifact is introduced into an environment, the artifact generates spatially uniform stress, but the environment responds differentially to that stress. In the case of reservoir-induced seismicity, the water load on the underlying rocks generates stress that is spatially uniform, but the varying structures of the rock strata and their permeability cause the environment to respond differently to that stress, leading to seismic activity in certain regions and not in others. Therefore, option  (E)  is the correct answer.

Answer: E

Sajjad1994 · Answer

Explanation

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

Explanation

The passage discusses the relationship between reservoirs and earthquakes. It explains that the large mass of water in a reservoir changes the stress patterns in the underlying rocks, and that the seismic activity induced by the reservoir depends on the rate of water level change and the permeability of the rocks. The passage then focuses on the Nurek reservoir in the Soviet Union and explains that the location of induced seismicity is related to the varying structures of the rock strata and the different permeabilities such structures engender. In particular, the passage discusses two types of rock formations, a syncline and an anticline, and explains how water interacts with these formations to generate seismicity.

The correct answer is  (D) . The passage states that in the region of the anticline, water entering a permeable layer 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. Therefore, (D) correctly describes the interaction of water and rock strata in the region of the anticline under the Nurek reservoir.  Answer choices (A), (B), (C) , and  (E)  do not accurately reflect the passage's explanation of how water interacts with the rock strata in the region of the anticline.

Answer: D

Sajjad1994 · Answer

Explanation

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

Explanation

The passage discusses the phenomenon of reservoir-induced seismicity and explains the factors that govern its occurrence at the Nurek reservoir in the Soviet Union. The passage suggests that an accurate prediction of reservoir-induced earthquake activity at the Nurek site would have required data related to the geological survey and the structure of the rock strata, the number and magnitude of the fluctuations in the water level, and the load created by the total mass of water in the reservoir. However, there is no mention of the chemical properties of the water used to fill the reservoir. Therefore, the correct answer is  (E)  a determination of the chemical properties of the water that would be used to fill the reservoir.

Answer: E

Sajjad1994 · Answer

Explanation

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?

Explanation

The passage discusses the relationship between reservoirs and earthquakes, specifically how the mass of water in a reservoir can change stress patterns in underlying rocks and lead to seismic activity. The passage also describes the example of the Nurek reservoir and how the location of induced seismicity is related to the varying structures and permeabilities of rock strata.

The question asks what would be true if the rate of change in the water level in the reservoir were very gradual. The passage does not provide a direct answer, but we can use the information provided to eliminate answer choices and make an educated guess.

(A) Stress patterns in the rock strata beneath the reservoir would be the same as before its construction.
This answer choice contradicts the information in the passage, which states that the mass of water in a reservoir can change stress patterns in underlying rocks. Therefore, this answer choice is incorrect.

(B) The seismic activity beneath the reservoir would not be very frequent.
The passage suggests that variations in the amount of water in the reservoir can trigger bursts of seismic activity, with the frequency increasing as the rate of level change increases. Therefore, if the rate of change in the water level were very gradual, it is possible that seismic activity would be less frequent. This answer choice is a possible answer.

(C) The spatial distribution of seismic activity beneath the reservoir would be altered.
The passage does not provide information to support or refute this answer choice. Therefore, this answer choice is uncertain.

(D) The rate of infiltration into rock strata below the reservoir would increase.
The passage states that the rate of infiltration into rock strata depends on their permeability and prior water content. The rate of change in the water level in the reservoir does not affect the permeability or prior water content of the rock strata, so this answer choice is incorrect.

(E) The stress patterns in the rocks underlying the reservoir would be less affected by vertical load.
The passage suggests that the mass of water in a reservoir exerts a simple vertical pressure on the rocks immediately. Therefore, if the rate of change in the water level were very gradual, the stress patterns in the rocks underlying the reservoir would still be affected by vertical load. This answer choice is incorrect.

Based on the information in the passage, the most likely answer is (B) The seismic activity beneath the reservoir would not be very frequent. If the rate of change in the water level in the reservoir were very gradual, it is possible that seismic activity would be less frequent.

Answer: B

Sajjad1994 · Answer

Explanation

9. The author of the passage is primarily concerned with

Explanation

The author of the passage is primarily concerned with explaining a relationship. Specifically, the author discusses the relationship between the construction of large reservoirs and the occurrence of earthquakes, with a focus on how the stress patterns in the underlying rocks are affected by the water load and how this can lead to seismic activity. The passage does not advance a theory, resolve a dispute, correct an oversimplification, or reinterpret data, so  options A, B, D,  and  E  can be eliminated. Therefore, the correct answer is  (C)  explaining a relationship.

Answer: C

consistentprep · Answer

"3) understanding of paragraph - contrast word ""Yet"" and question asked ?
“Lithologically similar” = The rock types (composition) in both areas (the one that has earthquakes and the one that doesn’t) are the same.
Those rocks include:Limestone = fractured and permeable.
Shale and gypsum = less permeable 
So basically: both areas have a mix of the same kinds of rocks.
But only one of the areas has earthquake activity (seismic), and the other doesn’t (aseismic), even though the rock composition is the same.

9) advancing a theory :The passage discusses an already accepted idea (reservoirs can cause earthquakes), and gives evidence.It doesn’t propose a new theory.
 resolving a dispute :The passage mentions there was skepticism in the past, but that’s no longer the case.There’s no ongoing dispute being settled here.
 author is explaining a relationship: Between the structure of rock layers (folds) and the occurrence of reservoir-induced earthquakes."

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

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

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