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# Geologists believe that the warning signs for a major earthquake may

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Geologists believe that the warning signs for a major earthquake may  [#permalink]

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Updated on: 12 Oct 2018, 01:14
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Question Stats:

65% (01:20) correct 35% (01:27) wrong based on 2067 sessions

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Geologists believe that the warning signs for a major earthquake may include sudden fluctuations in local seismic activity, tilting and other deformations of the Earth's crust, changing the measured strain across a fault zone, and varying the electrical properties of underground rocks.

(A) changing the measured strain across a fault zone, and varying

(B) changing measurements of the strain across a fault zone, and varying

(C) changing the strain as measured across a fault zone, and variations of

(D) changes in the measured strain across a fault zone, and variations in

(E) changes in measurements of the strain across a fault zone, and variations among

Verbal Question of The Day: Day 145: Sentence Correction

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Originally posted by goalsnr on 18 Jul 2008, 09:16.
Last edited by Bunuel on 12 Oct 2018, 01:14, edited 1 time in total.
Renamed the topic and edited the question.
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QOTD: Geologists believe that the warning signs  [#permalink]

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30 Oct 2017, 06:33
19
7
This is a gnarly question that operates at the intersection of parallelism and meaning. The basics of parallelism aren’t all that hard, but then the GMAT turns them into a goofy logic puzzle. More on that in our webinar on parallelism and meaning if you haven’t already seen it.

Quote:
(A) changing the measured strain across a fault zone, and varying

Superficially, the parallelism doesn’t look awful here, but it’s not quite right. The sentence revolves around a list of “warning signs for a major earthquake”, and the non-underlined portion features the first two items in the list (“sudden fluctuations” and “tilting and other deformations”), both of which are nouns.

So we need those last two items in the list to be nouns that are logically parallel to “sudden fluctuations” and “tilting and other deformations.” But I don’t think we actually have nouns in the underlined portion: “changing” and “varying” seem to be structured as modifiers, not nouns.

To be fair, this is tricky as hell: as discussed in our article on “-ing” words, “-ing” words could be modifiers or nouns (also known as gerunds), depending on how they’re used. In this particular case, there’s no clear indication that “changing” and “varying” are nouns. If (A) said “the changing of measured strain” and “the varying of electrical properties”, then you could convince me that these are parallel nouns.

Another way of thinking about this: what, exactly, are the signs of major earthquakes? Is it “changing the measured strain across the fault zone”? That doesn’t really make sense: the phrase suggests that the act of changing the measurement is the “sign of a major earthquake.” In reality, the sign of the earthquake is changes in the strain – not changes to the measurement itself.

So whether you’re thinking about meaning or structure, (A) is wrong. If you wanted to be conservative on your first pass through (never a bad idea!), you could keep (A), but there are better options available.

Quote:
(B) changing measurements of the strain across a fault zone, and varying

(B) is a slightly better version of (A), but it still isn’t quite good enough. Sure, “changing measurements” is clearly a noun now, with “changing” serving as an adjective. But it still incorrectly implies that the measurements are changing, and not the strain itself. And “varying” still looks like a modifier.

So (B) is out.

Quote:
(C) changing the strain as measured across a fault zone, and variations of

(C) is more tempting than (A) or (B), but it’s still not quite right. “Changing the strain” still has the same problem we described in (A): “changing” isn’t necessarily a noun here, and the act of “changing the strain” really isn’t a sign of a major earthquake – it’s much clearer to say that “changes in the strain” are a sign of an earthquake.

So we can probably do better than (C), too.

Quote:
(D) changes in the measured strain across a fault zone, and variations in

Here we go! Now the list consists only of nice, straightforward, unambiguous nouns: “warning signs for a major earthquake include… changes in the measured strain… and variations in the electrical properties of rocks.” Those are nouns, without any doubt.

And just as importantly, they make perfect sense as warning signs for an earthquake. Let’s keep (D).

Quote:
(E) changes in measurements of the strain across a fault zone, and variations among

The differences between (D) and (E) are pretty subtle. (E) gives us a pair of nouns, so it’s structurally parallel – but the meaning doesn’t work anymore. “…changes in measurements of the strain” are NOT signs of an earthquake: if the measurement changes, that doesn’t necessarily mean that the strain itself has changed. For that reason alone, we could ditch (E).

Plus, the phrase “variations among” doesn’t quite work. If we talk about “variations among curry recipes”, we’re saying that different recipes have different characteristics. So “variations among electrical properties of rocks” would suggest that the different electric properties of rocks are… well, different from each other. But that isn’t what we’re trying to say: the point of the sentence is that the electrical properties of individual rocks vary before a major earthquake. So “variations in” is much, much clearer.

Ugh. Having fun yet? (E) is out, and (D) wins.
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Re: Geologists believe that the warning signs for a major earthquake may  [#permalink]

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29 Aug 2013, 01:19
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Marcab wrote:
Guys I would like to ask all of you that how can "sudden fluctuations" and "tilting" be parallel?
"tilting" is a simple gerund and "fluctuations" is an action noun, and according to MGMAT SC, simple gerunds and action nouns can't be parallel.
So the sentence goes like this:
Geologists believe that the warning signs for a major earthquake may include [sudden fluctuations in( local seismic activity, tilting and other deformations of the earth's crust)], changing the measured strain across a fault zone, and variations in/of the electrical properties of underground rocks.

Regarding the preposition, MGMAT says that there is no compulsion on the prepositions to be the same.

Correct me if I am wrong.

according to Manhattan SC:
simple gerund should be parallel to simple gerund ONLY
complex gerund can be parallel to action nouns

look at the answer choice D. in this example, we have following warning signs for a major earthquake: sudden fluctuation in local seismic activities, tilting of the Earth's crust, changes in the measured strain across a fault zone, and variations in the electrical properties of underground rocks. now examine words in bold - fluctuation is an action noun (from verb fluctuate), changes is an action noun (from verb change), variations is an action noun (from verb vary) and as for tilting of, it is a complex gerund phrase, since complex gerund phrases are "noun through and through", which means that if you look inside the phrase, you can not turn it into a working verb. for example, try to place some noun inside the phrase "tilting of the earth's crust", such as "earthquake is tilting of the earth's crust" - you will see that this sentence does not make sense, cause it can not be turned into working verb (because of having Of-preposition in the phrase).

to sum it up, three action nouns (fluctuation, changes, variation) and one complex gerund (tilting of) are made parallel. so correct answer choice is D.

hope it helps.
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Re: Geologists believe that the warning signs for a major earthquake may  [#permalink]

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18 Jul 2008, 18:16
4
goalsnr wrote:
Geologists believe that the warning signs for a major earthquake may include sudden fluctuations in local seismic activity, tilting and other deformations of the Earth's crust, changing the measured strain across a fault zone, and varying the electrical properties of underground rocks.

A. changing the measured strain across a fault zone, and varying

B. changing measurements of the strain across afault zone, and varying

C. changing the strain as measured across a faultzone, and variations of

D. changes in the measured strain across a faultzone, and variations in

E. changes in measurements of the strain across a fault zone, and variations among

OA is D.

This SC i stesting for IIlism.
Geologists believe that the warning signs for a major earthquake may include A,B,C and D

Geologists believe that the warning signs for a major earthquake may include
-sudden fluctuations in local seismic activity,
-tilting and other deformations of the Earth's crust,
-changes in the measured strain across a faultzone, and
-variations in the electrical properties of underground rocks
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Re: Geologists believe that the warning signs for a major earthquake may  [#permalink]

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18 Oct 2012, 23:31
Guys I would like to ask all of you that how can "sudden fluctuations" and "tilting" be parallel?
"tilting" is a simple gerund and "fluctuations" is an action noun, and according to MGMAT SC, simple gerunds and action nouns can't be parallel.
So the sentence goes like this:
Geologists believe that the warning signs for a major earthquake may include [sudden fluctuations in( local seismic activity, tilting and other deformations of the earth's crust)], changing the measured strain across a fault zone, and variations in/of the electrical properties of underground rocks.

Regarding the preposition, MGMAT says that there is no compulsion on the prepositions to be the same.

Correct me if I am wrong.
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Re: Geologists believe that the warning signs for a major earthquake may  [#permalink]

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19 Sep 2013, 13:16
3
1
goalsnr wrote:
Geologists believe that the warning signs for a major earthquake may include sudden fluctuations in local seismic activity, tilting and other deformations of the Earth's crust, changing the measured strain across a fault zone, and varying the electrical properties of underground rocks.

A. changing the measured strain across a fault zone, and varying
B. changing measurements of the strain across afault zone, and varying
C. changing the strain as measured across a faultzone, and variations of
D. changes in the measured strain across a faultzone, and variations in
E. changes in measurements of the strain across a fault zone, and variations among

D It is.

Geologists believe that the warning signs for a major earthquake may include j, k, l, and m. These j, k, l, m are the items in a list of a warning signs. Hence needs to be parallel.

The first two items are in the form of Adjectival Phrases 1) sudden fluctuations..... 2)tilting ...... of the earth's crust.
So to take care of parallelism remaining two items also need to be in the form of Adjectival phrase.

A) INCORRECT :- changing and varying are verbs, which can not parallel to phrases

B) INCORRECT :- varying is verb, which can not parallel to phrase. Also Change is in the strain and not in the measurements.

C) INCORRECT :- changing is verb, which can not parallel to phrase.

D) CORRECT :- This choice makes the remaining two signs parallel to previous signs. changes...... variations.....

E) INCORRECT :- changes are in the strain and not in the measurements.

Hope That Helps!
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Re: Geologists believe that the warning signs for a major earthquake may  [#permalink]

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30 Oct 2015, 01:07
1
2
Yes, this is a tough one. The choice between D and E requires some really fine detail work. As several people have said, "among" is wrong because, in contrast to the meaning of A-D, that would be a comparison from one rock to another. It would be odd to expect the properties of all rocks to be the same in the first place. Additionally, changes in measurement shouldn't be a sign of an earthquake. We should be looking for changes in the thing we are measuring--strain. That makes this element parallel with the other signs--fluctuations in activity, tilting of the crust, etc.

As for developing a checklist, you don't want to do it! It certainly wouldn't have helped with D vs. E. If you were writing a computer program, sure, but you won't be able to apply that checklist efficiently on the test. Here's what I recommend:

1) Start by looking at the basic core of the sentence. Skip over modifiers to see the simple subject, verb, etc. Here, that would be "Geologists believe that the signs may include fluctuations, tilting and other deformations, changing, and varying." (Notice that I've left out adjectives and prepositional phrases.) The subject-verb relationships ("Geologists believe" and "signs may include") are fine, but the second half of the sentence has parallelism problems. That gets rid of A-C right away.

2) Once you've settled any issues with the core (sometimes there are none), you can start looking at meaning, modifiers, etc., but there's no time to go down a list. What's more helpful is to train yourself to spot these issues when they show up. See a sentence that starts with "Unlike"? Expect a comparison issue. See a modifier that moves around? Look at how it affects the meaning.

3) If you get stuck, guess and move on! There is nothing wrong with guessing between the final two on a question like this, even if you are aiming for 700+. Know when you are beat and save your time for problems you are able to resolve with confidence!
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Re: Geologists believe that the warning signs for a major earthquake may  [#permalink]

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02 Mar 2017, 09:00
1
Geologists believe that the warning signs for a major earthquake may include sudden fluctuations in local seismic activity, tilting and other deformations of the Earth’s crust, changing the measured stain across a fault zone, and varying the electrical properties of underground rocks.

Issue: Parallelism | Meaning

Analysis:
1. The sentence can be broken down as following and the main issue at play here is parallelism. We need to make sure that all the warnings sign should be parallel is form. In the non-underlined part of the sentence, the warning sign are mentioned as noun. Hence, the warning sign in the underlined part should also be noun.

Geologists believe

that

warning signs... include
│
├─ fluctuations...,
│
├─ tilting and other deformations...,
│
├─ changes...
│
and
└─ variations...

(A) changing the measured strain across a fault zone, and varying
- "changing" and "varying" used as a verb here; not parallel with nouns

(B) changing measurements of the strain across a fault zone, and varying
- "changing" and "varying" used as a verb here; not parallel with nouns

(C) changing the strain as measured across a fault zone, and variations of
- "changing" used as a verb here; not parallel with nouns

(D) changes in the measured strain across a fault zone, and variations in

(E) changes in measurements of the strain across a fault zone, and variations among
- Illogical meaning; "Changes in measurement" is not the warning but rather "change in measured strain" is

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Re: Geologists believe that the warning signs for a major earthquake may  [#permalink]

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24 Jun 2017, 07:37
Geologists believe that the warning signs for a major earthquake may include sudden fluctuations in local seismic activity, tilting and other deformations of the Earth's crust, changing the measured strain across a fault zone, and varying the electrical properties of underground rocks.

(A) changing the measured strain across a fault zone, and varying
(B) changing measurements of the strain across a fault zone, and varying
(C) changing the strain as measured across a fault zone, and variations of
(D) changes in the measured strain across a fault zone, and variations in
(E) changes in measurements of the strain across a fault zone, and variations among

Do "sudden fluctuations..." result in "changing.." and "varying.." -> honestly I don´t know. If it was so: A,B,C stand a chance. But then before the "and varying" there is a "," -> "and varying" -> this implies that this is part of a list of more than 2 items. Therefore A, B, C are out as "changing" and "varying" are not parallel to "fluctuations".. we need "changes" and "variations"
D is even better as "changes in" and "variations in" is parallel to "fluctuations in".

Did I do the analysis correctly? somehow I doubt

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Re: Geologists believe that the warning signs for a major earthquake may  [#permalink]

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30 Jun 2017, 10:20
2
Sahil01 wrote:
Geologists believe that the warning signs for a major earthquake may include sudden fluctuations in local seismic activity, tilting and other deformations of the Earth's crust, changing the measured strain across a fault zone, and varying the electrical properties of underground rocks.

(A) changing the measured strain across a fault zone, and varying
(B) changing measurements of the strain across a fault zone, and varying
(C) changing the strain as measured across a fault zone, and variations of
(D) changes in the measured strain across a fault zone, and variations in
(E) changes in measurements of the strain across a fault zone, and variations among

Do "sudden fluctuations..." result in "changing.." and "varying.." -> honestly I don´t know. If it was so: A,B,C stand a chance. But then before the "and varying" there is a "," -> "and varying" -> this implies that this is part of a list of more than 2 items. Therefore A, B, C are out as "changing" and "varying" are not parallel to "fluctuations".. we need "changes" and "variations"
D is even better as "changes in" and "variations in" is parallel to "fluctuations in".

Did I do the analysis correctly? somehow I doubt

Hello Sahil01,

I would be glad to provide my two cents on the analysis that you ave presented.

The comma + verb-ing modifier modifies the preceding action. In this official question, the action that precedes comma + changing and varying is may include. This is for certain that just enumerating signs of something cannot lead to change or variation in anything. Hence, most definitely comma + changing and varying are NOT meant to be modifiers in this official sentence.

Hence, the sentence clearly tests parallelism. Personally, I do not rely on punctuation marks to accept or reject an answer choice.

Now that I am sure that the parallel list contains four elements that need to be parallel, I reject choice A, B, and C.

Between Choice D and E, D is definitely the correct one because the warning sign of a major earthquake will be change in the strain and not the change in the measurements of the strain.

Logic all the way and I get my correct answer.

Hope this helps.
Thanks.
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Re: Geologists believe that the warning signs for a major earthquake may  [#permalink]

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30 Jun 2017, 18:54
Quote:

The comma + verb-ing modifier modifies the preceding action. In this official question, the action that precedes comma + changing and varying is may include. This is for certain that just enumerating signs of something cannot lead to change or variation in anything. Hence, most definitely comma + changing and varying are NOT meant to be modifiers in this official sentence.
at

Hi egmat

I had a similar query for coma+verb-ing modifiers since I selected OA as A.
I request you to help me with below understanding based on your reply:

Why the first modifier tilting is then used correctly?

The warning signs for a major earthquake include 4 things - a,b,c,& d. In this case - a,b,c,&d need to be parallel.

a - Sudden fluctuations in ..
b - tilting and other deformations of
c - (need to keep the consistency of writing) changes in the measured strain
d - variations in

As per my views, noun phrase (sudden fluctuations in ..) in (a) seems parallel
with verb-ing modifier tilting + of..(b) and nouns phrases changes
in
(c) and variations in (d): which is correct from grammar point of view.

Also variations in rocks and variations among rocks too convey different meaning?

WR,
Arpit
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Re: Geologists believe that the warning signs for a major earthquake may  [#permalink]

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28 Jul 2017, 09:30
2

Hi egmat

I had a similar query for coma+verb-ing modifiers since I selected OA as A.
I request you to help me with below understanding based on your reply:

Why the first modifier tilting is then used correctly?

The warning signs for a major earthquake include 4 things - a,b,c,& d. In this case - a,b,c,&d need to be parallel.

a - Sudden fluctuations in ..
b - tilting and other deformations of
c - (need to keep the consistency of writing) changes in the measured strain
d - variations in

As per my views, noun phrase (sudden fluctuations in ..) in (a) seems parallel
with verb-ing modifier tilting + of..(b) and nouns phrases changes
in
(c) and variations in (d): which is correct from grammar point of view.

Also variations in rocks and variations among rocks too convey different meaning?

WR,
Arpit

Thank you for the query.

The word tilting is NOT a modifier. It is the "ing" noun form and hence is parallel to other noun phrases in the list.

Please note that tilting is NOT a gerund - an "ing" noun that denotes action. It is so because in the original sentence, tilting is followed by the preposition of. One of the warning signs includes tilting of the Earth's crust and other deformations of the Earth's crust. Gerunds are never followed by a preposition.

So the noun form tilting is perfectly parallel to the other noun phrases in the list.

And yes, variations in and variations among are not same. They do denote different meanings. quite literally.

Hope this helps.
Thanks.
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Re: QOTD: Geologists believe that the warning signs  [#permalink]

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30 Oct 2017, 07:09
2
Geologists believe that the warning signs for a major earthquake may include sudden fluctuations in local seismic activity, tilting and other deformations of the Earth's crust, changing the measured strain across a fault zone, and varying the electrical properties of underground rocks.

Understanding the intended meaning : After reading the sentence its clear that the sentence is talking about the list of warning signs for a major earthquake as believed by the geologists.

At first look, though, I even had a thought whether "tilting" is acting like a VERB-ing modifier and the remaining two -ing forms (changing and varying) are parallel to the tilting. So, I quickly checked the same. The VERB-ing modifiers should make sense with the SUBJECT and VERB of the preceding clause. Here, preceding clause is an essential modifier.

Preceding Clause -- the warning signs for a major earthquake (SUBJECT) may include (VERB) sudden fluctuations in local seismic activity, tilting...
This is for certain that just enumerating signs of something cannot lead to tilting in anything. Though Tilting can be included as a part of this list. Hence, most definitely comma + tilting is NOT meant to be a modifier in this sentence. Then what is this "tilting"?? It is acting as an ACTION NOUN or more technically, Complex Gerund. SO, from here we got that the remaining portions of the underlined part should also be nouns for the list to be parallel. So, need to quickly go through the choices to look for parallelism.

(A) changing the measured strain across a fault zone, and varying
varying is NOT the noun form. Therefore, it breaks parallelism. ALso, usage of "changes" is better than "changing". When a noun form is available, we prefer not to use the "-ING" form of verbs. Incorrect.

(B) changing measurements of the strain across a fault zone, and varying
varying is NOT the noun form. Therefore, it breaks parallelism. Also, there is a meaning issue with this choice. Changing measurements of the strain is not correct. Changing the measured strain is the intended meaning. ALso, usage of "changes" is better than "changing". When a noun form is available, we prefer not to use the "-ING" form of verbs. Incorrect.

(C) changing the strain as measured across a fault zone, and variations of
changes is better than changing. Also, when a noun form is available, we prefer not to use the "-ING" form of verbs. Variations of is non idiomatic. Therefore, incorrect.

(D) changes in the measured strain across a fault zone, and variations in
CHANGES is a proper noun form, compared to CHANGING. Also, the intended meaning -- changes in the strain is clear. Usage of "Variations in" is idiomatic. Correct.

(E) changes in measurements of the strain across a fault zone, and variations among
Similar issue in meaning as choice B. Also, variations among is NOT idiomatic. Incorrect.
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Re: QOTD: Geologists believe that the warning signs  [#permalink]

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30 Oct 2017, 09:40
aceGMAT21 wrote:
Geologists believe that the warning signs for a major earthquake may include sudden fluctuations in local seismic activity, tilting and other deformations of the Earth's crust, changing the measured strain across a fault zone, and varying the electrical properties of underground rocks.

Understanding the intended meaning : After reading the sentence its clear that the sentence is talking about the list of warning signs for a major earthquake as believed by the geologists.

At first look, though, I even had a thought whether "tilting" is acting like a VERB-ing modifier and the remaining two -ing forms (changing and varying) are parallel to the tilting. So, I quickly checked the same. The VERB-ing modifiers should make sense with the SUBJECT and VERB of the preceding clause. Here, preceding clause is an essential modifier.

Preceding Clause -- the warning signs for a major earthquake (SUBJECT) may include (VERB) sudden fluctuations in local seismic activity, tilting...
This is for certain that just enumerating signs of something cannot lead to tilting in anything. Though Tilting can be included as a part of this list. Hence, most definitely comma + tilting is NOT meant to be a modifier in this sentence. Then what is this "tilting"?? It is acting as an ACTION NOUN or more technically, Complex Gerund. SO, from here we got that the remaining portions of the underlined part should also be nouns for the list to be parallel. So, need to quickly go through the choices to look for parallelism.

(A) changing the measured strain across a fault zone, and varying
varying is NOT the noun form. Therefore, it breaks parallelism. ALso, usage of "changes" is better than "changing". When a noun form is available, we prefer not to use the "-ING" form of verbs. Incorrect.

(B) changing measurements of the strain across a fault zone, and varying
varying is NOT the noun form. Therefore, it breaks parallelism. Also, there is a meaning issue with this choice. Changing measurements of the strain is not correct. Changing the measured strain is the intended meaning. ALso, usage of "changes" is better than "changing". When a noun form is available, we prefer not to use the "-ING" form of verbs. Incorrect.

(C) changing the strain as measured across a fault zone, and variations of
changes is better than changing. Also, when a noun form is available, we prefer not to use the "-ING" form of verbs. Variations of is non idiomatic. Therefore, incorrect.

(D) changes in the measured strain across a fault zone, and variations in
CHANGES is a proper noun form, compared to CHANGING. Also, the intended meaning -- changes in the strain is clear. Usage of "Variations in" is idiomatic. Correct.

(E) changes in measurements of the strain across a fault zone, and variations among
Similar issue in meaning as choice B. Also, variations among is NOT idiomatic. Incorrect.

Hello aceGMAT21,

Your meaning-based approach to solve this official question is very thorough. Great job there. Keep it up.

It is true that one mat think that comma + tilting might have been used a comma + verb-ing modifier in this official sentence. However, if just pay attention to the structure of this part of the sentence, we will know that tilting is a noun.

The word tilting in the non-underlined portion is followed and. Presence of and suggests that there is a list in here. What follows and, i.e., the last entity in the list is other deformations, a noun entity. Hence, titling has to be a noun to form a parallel list with other deformations.

Hope this helps.
Thanks.
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Re: QOTD: Geologists believe that the warning signs  [#permalink]

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30 Oct 2017, 12:08
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Geologists believe that the warning signs for a major earthquake may include sudden fluctuations in local seismic activity, tilting and other deformations of the Earth's crust, changing the measured strain across a fault zone, and varying the electrical properties of underground rocks.

A) changing the measured strain across a fault zone and varying
(B) changing measurements of the strain across a fault zone, and varying
(C) changing the strain as measured across a fault zone, and variations of
(D) changes in the measured strain across a fault zone, and variations in
(E) changes in measurements of the strain across a fault zone, and variations among

Notwithstanding what has been given in the non-underlined part, structurally speaking, the ", changing" in A, B and C absurdly imply that the subject of the previous clause namely 'the signs' is the doer of the said actions. Therefore neck them out in one go.
Then it does not take much to dump for the unidiomatic 'variations among'. In addition, choice E changes the intent to say that the measurements have changed rather than the original measured strains.
A nice meaning based question although structure and parallelism play a major role in diagnosing incorrect choices.
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Geologists believe that the warning signs for a major earthquake may  [#permalink]

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27 Dec 2018, 08:30
Geologists believe that the \$warning signs\$ for a major earthquake \$may include\$ sudden [fluctuations] in local seismic activity, tilting and other [deformations] of the Earth's crust, changing the measured strain across a fault zone, \$and\$ varying the electrical properties of underground rocks.

(A) <<changing>> the measured strain across a fault zone, \$and\$ <<varying>>
changing , varying - verb form which are not parallel to the noun list

(B) <<changing>>measurements of the strain across a fault zone, \$and\$ <<varying>>
changing - verb form which is not parallel to the noun list

(C) <<changing>> the strain as measured across a fault zone, \$and\$ [variations] of
changing , varying - verb form which are not parallel to the noun list

(D) [changes] in the measured strain across a fault zone, [and] [variations] in
changes , variations - noun form which are parallel to the noun list

(E) [changes in <measurements>] of the strain across a fault zone, [and] [variations <among> ]
+ the meaning is illogical
1)changes in the measurements and not the strains
2) variations among the electrical properties and not in the electrical properties itself

<< >> - verb phrases
[ ] - noun phrases
<> - errors
\$ \$ - keywords

in this sentence we are looking for a list of noun phrases, [x],[y], \$and\$ [z] and the list is indicated by the key words \$warning signs\$ \$may include\$
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Re: Geologists believe that the warning signs for a major earthquake may  [#permalink]

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05 Jul 2019, 21:55
May include
X= fluctuations in another list
Y=changes
Z=variations
May include X, Y, and Z (a list)
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Re: Geologists believe that the warning signs for a major earthquake may  [#permalink]

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08 Jul 2019, 02:54
gravito123 wrote:
May include
X= fluctuations in another list
Y=changes
Z=variations
May include X, Y, and Z (a list)
That other list is not part of the first element.

Geologists believe that the warning signs for a major earthquake may include
(a) sudden fluctuations in local seismic activity,
(b) tilting and other deformations of the Earth's crust,
(c) changes in the measured strain across a fault zone,
and
(d) variations in the electrical properties of underground rocks.
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Re: Geologists believe that the warning signs for a major earthquake may   [#permalink] 08 Jul 2019, 02:54
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