Prior to 1965 geologists assumed that the two giant rock plates

Question

Prior to 1965 geologists assumed that the two giant rock plates meeting at the San Andreas Fault generate heat through friction as they grind past each other,but in 1965 Henyey found that temperatures in drill holes near the fault were not as elevated as had been expected.

It doesnt say that friction doesn't generate heat. In passage, it became more clear that "whether the friction between the plates was being reduced by pockets of pressurized water within the fault that push the plates away from each other." so there are other fact in play such as pressure that reduces friction. That explain "that temperatures in drill holes near the fault were not as elevated as had been expected."

In 1992 Byerlee tested whether these materials would produce friction 10 to 15 kilometers below the Earth’s surface. Byerlee found that when clay samples were subjected to the thousands of atmospheres of pressure they would encounter deep inside the Earth, they produced as much friction as was produced by other rock types. The harder rocks push against each other, the hotter they become; in other words, pressure itself, not only the rocks’ properties, affects frictional heating. Geologists therefore wondered whether the friction between the plates was being reduced by pockets of pressurized water within the fault that push the plates away from each other   1 
 1. The passage suggests which of the following regarding Henyey’s findings about temperature in the San Andreas Fault?

(A) Scientists have yet to formulate a definitive explanation for Henyey’s findings.
(B) Recent research suggests that Henyey’s explanation for the findings should be modified.
(C) Henyey’s findings had to be recalculated in light of Byerlee’s 1992 experiment.
(D) Henyey’s findings provided support for an assumption long held by geologists.
(E) Scientists have been unable to duplicate Henyey’s findings using more recent experimental methods.

2 
 2. The passage is primarily concerned with 
 
(A) evaluating a method used to test a particular scientific hypothesis
(B) discussing explanations for an unexpected scientific finding 
(C) examining the assumptions underlying a particular experiment
(D) questioning the validity of a scientific finding
(E) presenting evidence to support a recent scientific hypothesis

3 
 3. The passage mostly agree that Henyey’s findings about temperature in the San Andreas Fault made the greatest contribution in that they

(A) revealed an error in previous measurements of temperature in the San Andreas Fault zone
(B) indicated the types of clay present in the rocks that form the San Andreas Fault
(C) established the superiority of a particular technique for evaluating data concerning friction in the San Andreas Fault
(D) suggested that geologists had inaccurately assumed that giant rock plates that meet at the San Andreas Fault generate heat through friction
(E) confirmed geologists’ assumptions about the amount of friction generated by common varieties of rocks, such as limestone and granite

4 
 4. According to the passage, Henyey's findings in 1965 were significant because they

(A) revealed an error in previous measurements of temperature in the San Andreas Fault zone
(B) indicated the types of clay present in the rocks that form the San Andreas Fault
(C) established the superiority of a particular technique for evaluating data concerning friction in the San Andreas Fault
(D) suggested that geologists had inaccurately assumed that giant rock plates that meet at the San Andreas Fault generate heat through friction
(E) confirmed geologists' assumptions about the amount of friction generated by common varieties of rocks, such as limestone and granite

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Carcass · Accepted Answer

Dissect the argument and boile it down to a simple scheme

Now the first sentence says: basically the scientists think that the heat among the earth's plates is caused by the friction of the rocks.

BUT in 1965 Henyey found that temperatures in drill holes near the fault were not as elevated as had been expected. . So after this something is weird: could not be this the real reason behind the friction and the consequent heat. Maybe is the type or quality of the rocks or clay or whatever else.

Byerlee's experiment instead says just this: no matter what is the type of rock, they genarate heat.

BUT  pressure itself, not only the rocks’ properties, affects frictional heating . Geologists  therefore wondered whether the friction between the plates was being reduced by pockets of pressurized water within the fault that push the plates away from each other.

Basically this is the skeleton of the argument that you have to keep in mind to answer the question. (indeed quite tricky) just because pressure + rock's properties could be the cause of all this but we are still wondering why Is this or there is something else that we do not know ??'

A fits the bill

hope this helps

saumya12 · Answer

Request the GC community to use spoilers, to conceal the answer key.

1: A. First thing to note is that Henyey just had "findings" and he did not offer an "explanation". So, B is out. His finding was that temperatures in drill holes near the fault were not as elevated as had been expected. Initially scientists thought that “weaker” materials, such as clays, were the reason for low temperatures; Byerlee proved that clay would also produce elevated temperatures. So, clearly, presence of clay did not provide an explanation to Henyey's findings". So, an alternate explanation needed to be looked at.

Geologists therefore wondered whether the friction between the plates was being reduced by pockets of pressurized water within the fault that push the plates away from each other.

The passage ends here. So, clearly this entire episode is still at a "wondering" stage. In other words, Scientists have yet to formulate a definitive explanation for Henyey’s findings.

2: B. The expectation was that two giant rock plates meeting at the San Andreas Fault would generate heat through friction. However, unexpected scientific finding was that Henyey did not find temperatures as elevated as had been expected. The whole passage that discusses explanation for this unexpected scientific finding.

3: D. First sentence of the passage is an assumption by geologists. Heney’s findings are counter to those assumptions.

roopika2990 · Answer

But 'temperatures in drill holes near the
fault were not as elevated as had 
been expected'

Doen't this show that A is correct?

plumber250 · Answer

Hi Roopika,

I don't think that it does.

Whilst Heyney found that temperatures were not that high, it says nowhere that anyone else had measured the temparature. The previous wisdom that temperatures were high, was not based on any actual data, just an assumption. 
So A is not correct.

Hope that helps.

James

Skywalker18 · Answer

1) The passage suggests which of the following regarding Henyey’s findings about temperature in the San Andreas Fault?
A. Scientists have yet to formulate a definitive explanation for Henyey’s findings. Correct
Some scientists had speculated that since clay was found in San Andreas Fault and rocks composed of clay produce far less friction than do other rock types .
However , Byerlee tests at a depth of 10-15 km below the Earth’s surface showed otherwise . Geologists also wondered whether the friction between the plates was being reduced by pockets of pressurized water .
B. Recent research suggests that Henyey’s explanation for the findings should be modified. Incorrect
There is no recent research mentioned in the passage that suggest about modification
C. Henyey’s findings had to be recalculated in light of Byerlee’s 1992 experiment. Incorrect
There is no discussion on recalculations of Henyey’s findings .
D. Henyey’s findings provided support for an assumption long held by geologists. Incorrect
Against the idea of pre 1965 geologists .
E. Scientists have been unable to duplicate Henyey’s findings using more recent experimental methods. Incorrect
The passage does not discuss about replication of Henyey’s findings .

2) The passage is primarily concerned with
B. discussing explanations for an unexpected scientific finding . Correct Answer
The unexpected finding was Henyey’s that temperatures in drill holes near fault was lower than expected .

3. The passage mostly agree that Henyey’s findings about temperature in the San Andreas Fault made the greatest contribution in that they

A. revealed an error in previous measurements of temperature in the San Andreas Fault zone - Prior to 1965 geologists assumed that the two giant rock plates meeting at the San Andreas Fault generate heat through friction as they grind past each other, but in 1965 Henyey found that temperatures in drill holes near the fault were not as elevated as had been expected.-- the temperature was not as high as expected (not as a previous measurement)

D. suggested that geologists had inaccurately assumed that giant rock plates that meet at the San Andreas Fault generate heat through friction - Correct

Show Spoiler

The passage was complicated . The third question was the most difficult .

Failed to get it correct even after taking 2 mins .
Got it correct on the second attempt

Failed to get it correct even after taking 2 mins . Got it correct on the second attempt

abrakadabra21 · Answer

3) The passage mostly agree that Heney’s findings about temperature in the San Andreas Fault made the greatest contribution in that they
A. revealed an error in previous measurements of temperature in the San Andreas Fault zone
B. indicated the types of clay present in the rocks that form the San Andreas Fault
C. established the superiority of a particular technique for evaluating data concerning friction in the San Andreas Fault
D. suggested that geologists had inaccurately assumed
that giant rock plates that meet at the San Andreas Fault generate heat through friction
E. confirmed geologists’ assumptions about the amount of friction generated by common varieties of rocks, such as limestone and granite

Prior to 1965 geologists assumed that the two giant rock plates meeting at the San Andreas Fault generate heat through friction as they grind past each other,but in 1965 Henyey found that temperatures in drill holes near the fault were not as elevated as had been expected.

It doesnt say that friction doesn't generate heat. In passage, it became more clear that "whether the friction between the plates was being reduced by pockets of pressurized water within the fault that push the plates away from each other." so there are other fact in play such as pressure that reduces friction. That explain "that temperatures in drill holes near the fault were not as elevated as had been expected." 
 
Why D is correct then?

abhimahna · Answer

Notice the word "inaccurately". Earlier geologists assumed that the heat produced is due to friction. But his findings helped geologists to determine other causes( such as gravitational pressure). Hence, D is the correct answer as it says his findings suggested that they were not 100% accurate.

anairamitch1804 · Answer

1) The first question was tough for me, but POE works here. 
Road map 
1) Prior 1965 assumption, followed by contradiction by Henyey. Scientists wonder .... 
2) 1922 old study, different rock types, clay and testing deep below.... 
After this study is described the last sentence says that Geologists therefore wonder.... 
 
A - Not sure, keep. 
B - Nothing about modification is mentioned in the 1965's study/research. 
C - Nothing is mentioned about this, there are only assumptions, nothing definitive to modify/recalculate. 
D - This was a bit tough. Ok, 1st sentence tells that there was some assumption prior to 1965(Prior to 1965 geologists assumed that....... ), this sentence is followed by a counter statement (, but in 1965 Henyey found that temperatures................) so this Henyey's study is not in the support of that assumption. Eliminate this option. 
E - Nothing about more recent experiments is mentioned, two experiments, one in 1922 one in 1965, thats all. Eliminate. 
A remains. ("Unexpected" findings and "wonder" words support this option) 
2)Prior to 1965 geologists assumed that the two giant rock plates meeting at the San Andreas Fault generate heat through friction as they grind past each other, but in 1965 Henyey found that temperatures in drill holes near the fault were not as elevated as had been expected.
^^ "Not as _____ as expected" is the same as "unexpected". So there's your unexpected finding.The entire rest of the passage is dedicated to hypotheses and/or research aimed at explaining what Henyey found. Hence B.
3)Prior to 1965 geologists assumed......... ..........., but in 1965 Henley found that......... . Hence D.

Rocket7 · Answer

WITH AN ATTEMPT TO MAKE RC FUN. I just typed what was going on in my mind while I was reading this passage. I thought to share it. It might have some typos or some stretched lyrics or extensions. Excuse that. Just an attempt.  gmatexam439  what you think. 
 
  Summary of the passage.

Para-1 
Before 1965 geologists thought that the heat that is produced in the SAF's (San Andreas Fault) is because of the friction between the rocks. However, in 1965 henyey (Hilary) found out that the temperature in the holes that were drilled in the SAF was not as elevated as thought by geologists. The geologists expected that the temperature will be high. Now the reason these geologists thought that the temperature in the drill holes should be high is because these geologists based their calculations of temperature measurement based on rocks that are made of granite or limestone. But they did not include the fact that rocks can be made of clay as well as clay was found in the samples from fault zone.

Predicting/ Forecasting/Wondering: 
if the rocks are made of clay then can they produce heat without frictions or what the hell is going on here. Also, why are the temperatures in the holes lower than expected.

Para- 2 
So in 1922 my boy Byerlee(Brue-Lee) tested the clay rocks, granite rocks and lime rocks 10 to 15 kilometers below the earth's surface to see if all these three types of rocks can produce friction. Wait what 10 to 15km below the earth’s surface. How the heck did he get an instrument that low into the ground. It's insane what these geologists can do han.

Anyways whatever method he used. He found out that the rocks made of clay produced as much friction as rocks that were made of granite and limestone. Now Bruce-Lee also mentioned that 10 to 15km below the earth, there are thousands of atmospheres of pressure. In other words, there is a hell a lot of pressure down in the earth.

So bruce-lee finds out what rocks are made of does not matter and what matters is how hard the rocks push against each other. If intensely with which they push against each other is higher then hotter they will become. So in nutshell the pressure not the properties of rock that determines the frictional heating. Hmm, it's almost like it does not matter how big or muscular you are but what matters is how smart you are. And Kudos to bruce-lee for finding all this info out.

Now after Hilary and Bruce-Lee found all this info. These Geologists wonder that can the pressurized water that's between the plates in the SAF is reducing the friction in between these plates. So is it that this water is pushing these rocks away from each other. Can this be the case????

Q What does the passage tell us about Hilary’s finding of the temperature in SAF? 
Prethink: Hilary found that the temperatures in drill holes are low and there could be a chance that all the geologists got all their calculations wrong coz they based the calculations of temperature levels on the rocks made of granite and line. They didn’t consider the possibility of rocks being made of clay.

A 
Meaning: Scientist still doesn’t have a definite explanation for Hilary’s findings. 
Reasoning: Yes.  Coz these scientists are still wondering.

B 
Reasoning: I mean based on the passage: Hilary’s research is the recent research. So the research itself does not ask for any modification.

C
Reasoning: No. it should not.

D
Reasoning: Not at all. Because before Hilary’s finding they didn’t even consider clay rocks possibility

E
Reasoning: Passage tells us nothing about duplication although I will be interested to learn.

Q What is the author trying to tell me here. I mean whats the point and whats this passage all about?  
Prethink: Hilary in 1965 shed a whole new light on the possibilities of low temperatures in holes and Hillary’s wisdom is somewhat supported by what bruce-lee had done in 1922. The point is we have made some progress in answering the low-temperature mystery but it's yet to be confirmed.

A 
Reasoning: He is not trying to tell us the methods that Brule-Lee or Hilary used.

B 
Reasoning:  Bingo and dingo. That’s what’s going on here! 
 
C
Reasoning: Author is not telling just about an assumption but the author is telling us how the assumption was acted upon and the reasoning behind it.

D
Reasoning: Author is not questioning if what Hilary and bruce-lee found or the new direction in which geologists are going is right or wrong.

E
Reasoning: Now we can say that he is presenting bruce-lee’s findings to try to support Hillary's point. However, this answer option is too narrow. From a macro level, he is trying to sort of tell us whats up with this mystery. In other words whats new with this mystery.

Q: So for the most part passage says that Hillary’s findings in regards to the temperature in SAF(San Andreas Fault) made an amazing contribution. But please elaborate what the contributions were actually or how did her findings made the amazing contributions:

Prethink: It's like we all have been looking for keys in the house and Hilary just said: guys did you check out the key hanger. The keys might just be there. In other words, geologists knew that there is clay in the samples but they never considered the possibility of rocks made of clay or making their calculations based on pressure instead of properties of rocks.

A 
Reasoning: Our mind here can say oh yeah. This is the right option. But look closely Hilary did not say that the calculations are wrong or there is an error in the calculation. She just found out that the temp is low in the holes and this finding initiated an alternate possibility. So for example in quant, we can solve for X correctly but rather we were supposed to solve for Y. Our calculation is correct but we just solved for a wrong variable.

B 
Reasoning: Not at all. She did not say what all types of clay rocks are there.

C
Reasoning: We have no idea about the technique that she used and neither is she a proponent of one over the other technique.

D
Meaning: the word used is suggested. And the basic meaning of this answer choice is that geologists assumption is inaccurate. 
Reasoning:  Yes. Because passage did refer that Hillary’s findings of low-temperature levels did undermine the assumption of geologists. 
 
E
Reasoning: No her research did not confirm that

jawele · Answer

Geologists'  pre-1965 assumptions concerning heat generated in the fault were based on    calculations   about common varieties of rocks, such as limestone and granite <...>.  this lead them to ->  ]  Prior to 1965 geologists assumed  that the two giant rock plates meeting at the San Andreas Fault generate heat through friction as they grind past each other, but in 1965 Henyey found that temperatures in drill holes near the fault were not as elevated as had been expected.

Q3 or 4:
(D) suggested that geologists had inaccurately assumed that giant rock plates that meet at the San Andreas Fault generate heat through friction  "suggested" plays a great trick here, making this choice correct, or at least I suppose that's the reason to pick D 
(A) revealed an error in previous measurements of temperature in the San Andreas Fault zone  but what about A? It seems reasonable based on the portions I've given above although it would also seem to be a stretch since the calculations might as well have been correct, but the basis (the types of rocks) was apparently incorrect

Please help me to spot what's wrong with A over here.

Thanks

workout   GMATNinjaTwo   u1983   GMATNinja   SajjadAhmad   Gnpth  or anybody else please

GMATNinja · Answer

The passage says that "Prior to 1965 geologists    assumed    that the two giant rock plates meeting at the San Andreas Fault generate heat through friction..." The passage doesn't say anything about ACTUAL temperature measurements before 1965. For all we know, there were no such measurements. In that case, we cannot say that Henyey's finding revealed an error (measurements that never existed can't have an error!).

Question #3, as posted, doesn't seem quite right ("The passage mostly agree..."). If anyone encounters this question in the software, please confirm that all questions are posted accurately and/or post screenshots. Thanks!

va789 · Answer

Hi Experts,

I'm unable to understand why for Q3, the answer is D. As per Option D, Henyey's findings suggested that it wasn't friction that was causing the heat, however, later in the passage it becomes clear that it was Byerlee's work that suggested this and not Henyey's.

Looking forward to your expert response.

GMATNinja · Answer

Question 3

Let’s take a look at (D):

All that (D) says is that Henyey’s work SUGGESTED that geologists had inaccurately assumed that heat was generated through friction. You’re correct to note that it is Byerlee’s work that  confirms  this suggestion by finding that even weaker materials would produce friction under such pressure. But Henyey is the first to suggest that the geologists’ assumption may not be correct. Ultimately, Henyey’s work proves important because it turns out that the geologists, indeed, were wrong to assume that the giant rock plates generated heat through friction. And it was Henyey’s work that provided the basis for Byerlee’s tests to confirm that geologists were wrong. Therefore, (D) is correct.

Honestly, I don’t love (D) when I first look at it either. But it is true that Henyey’s work is the first to SUGGEST that the geologists’ assumption may be incorrect. And this question is an excellent example of where finding four wrong answers, rather than one right answer, can be immensely beneficial. It may be hard to see why (D) is correct. But it’s easy to see why the other four answers are incorrect, making (D) the least wrong answer. And on that basis, we can choose (D).

I hope that helps!

Hoozan · Answer

EducationAisle   GMATNinja  please could you help me with Q3. A and D

When we read " but in 1965 Henyey found that temperatures in drill holes near the fault were not as elevated as had been expected. Some geologists wondered whether the  absence of friction-generated heat could be explained  " we can infer that there was no heat generated through the friction and thus we can get (D)

But can't we also get

I am not quite sure of the structure of this RC.  GMATNinja  you mentioned that "Byerlee" supports "Henyey". I understand that prior Geologists had an hypothesis that later "Henyey" proved wrong. But how does "Byerlee" add support to "Henyey". Doesn't "Byerlee" rather prove that friction-generated heat CAN be created from the weaker "clay" rocks while "Henyey" on the other hand proves that there was no friction-generated heat

GMATNinja · Answer

Question 3 
 
As we said in  our previous post , the problem with (A) is that we don’t actually know whether previous measurements of temperature in the San Andreas Fault zone were taken. All we know is that geologists  expected  to find elevated temperatures, but their expectations could have been based on pure theory and not past measurements. So, we don’t know if any past measurements actually contained errors.

As far as the relationship between Henyey and Byerlee, Henyey’s work suggests that the giant rock plates do not produce heat by friction at the San Andreas Fault. Byerlee’s work confirms that even weaker materials would produce more heat than is found at the San Andreas Fault. So, Byerlee confirms Henyey’s suggestion that heat is not being produced by friction at the San Andreas Fault.

I hope that helps!

NamanSachdeva · Answer

Can someone explain to me the 4th Question, please

"According to the passage, Henyey's findings in 1965 were significant because they"

I marked A but the answer is D

GMATNinja · Answer

Question 4 
 
According to the passage, Henyey found that "temperatures in drill holes near the fault were not as elevated as had been  expected ." So why had geologists  expected  the temperatures near the fault to be more elevated?

Earlier in the same sentence, we learn that "geologists  assumed  that the two giant rock plates meeting at the San Andreas Fault generate heat through friction." So because the geologists assumed there would be "heat generated through friction," they  expected  more elevated temperatures.

Notice that the temperatures were expected to be elevated NOT because they contradicted  previous measurements  of temperature, but because they were not consistent with the  assumptions  geologists had made about heat generated through friction.

Let's now consider (A):

As we've established, Henyey's findings were unexpected NOT because they contradicted " previous measurements of temperature ." In fact, the passage doesn't even mention any "previous measurements of temperature." So (A) is out.

Let's consider (D):

This is much better. As the passage says, Henyey's findings were unexpected because geologists had assumed that the "the two giant rock plates meeting at the San Andreas Fault generate heat through friction." So (D) is correct.

I hope that helps!

Rickooreo · Answer

The passage is primarily concerned with
A. evaluating a method used to test a particular scientific hypothesis
B. discussing explanations for an unexpected scientific finding
C. examining the assumptions underlying a particular experiment
D. questioning the validity of a scientific finding 
E. presenting evidence to support a recent scientific hypothesis

Can someone please explain how to eliminate option C, findings is based on some method used and method assumes something, each of the findings are challenged by questioning the assumption it seems.

GMATNinja · Answer

The problem with (C) is that the passage, as a whole, is not primarily concerned with the assumptions  underlying an experiment . The first paragraph discusses assumptions that scientists made prior to 1965 (about the type of rock that composed the San Andreas Fault). In 1965, measurements are taken that prove to be contrary to expectations. But there is no experiment.

In the second paragraph, an experiment is conducted to determine whether the fault could be made of clay. But that experiment isn't based on  assumptions  that the argument is examining. Instead, the experiment finds that clay would not explain the lower temperature of the fault. So, an alternative hypothesis is proposed. Because the passage isn't examining any underlying assumptions of a particular experiment, we can eliminate (C).

I hope that helps!

Prior to 1965 geologists assumed that the two giant rock plates

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Prior to 1965 geologists assumed that the two giant rock plates

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