[問題]GWD24-Q33

[bugubugu]

24-passage three

In most earthquakes the Earth’s crust cracks like porcelain. Stress builds up until a fracture forms at a depth of a few kilometers and the crust slips to relieve the stress. Some earthquakes, however, take place hundreds of kilometers down in the Earth’s mantle, where high pressure makes rock so ductile that it flows instead of cracking, even under stress severe enough to deform it like putty. How can there be earthquakes at such depths?
That such deep events do occur has been accepted only since 1927, when the seismologist Kiyoo Wadati convincingly demonstrated their existence. Instead of comparing the arrival times of seismic waves at different locations, as earlier researchers had done, Wadati relied on a time difference between the arrival of primary ( P ) waves and the slower secondary ( S ) waves. Because P and S waves travel at different but fairly constant speeds, the interval between their arrivals increases in proportion to the distance from the earthquake focus, or initial rupture point. For most earthquakes, Wadati discovered, the interval was quite short near the epicenter; the point on the surface where shaking is strongest. For a few events, however, the delay was long even at the epicenter. Wadati saw a similar pattern when he analyzed data on the intensity of shaking. Most earthquakes had a small area of intense shaking, which weakened rapidly with increasing distance from the epicenter, but others were characterized by a lower peak intensity, felt over a broader area. Both the P-S intervals and the intensity patterns suggested two kinds of earthquakes: the more (45) common shallow events, in which the focus lay just under the epicenter, and deep events, with focus several hundred kilometers down.
The question remained: how can such quakes occur, given that mantle rock at a depth of more than 50 kilometers is too ductile to store enough stress to fracture? Wadati’s work suggested that deep events occur in areas (now called Wadati-Benioff zones), where one crustal plate is forced under another and descends into the mantle. The descending rock is substantially cooler than the surrounding mantle and hence is less ductile and much more liable to fracture.


24-33 The passage suggests that which of the following must take place in order for any earthquake to occur?
I. Stress must build up
II. Cool rock must descend into the mantle.
III. A fracture must occur.
A) I only
B) II only
C) III only
D) I and III only
E) I, II and III


為何II不對阿?

[micht]

In[highlight=pink] most earthquakes [/highlight]the Earth’s crust cracks like porcelain. Stress builds up until a fracture forms at a depth of a few kilometers and the crust slips to relieve the stress. [highlight=pink]Some earthquakes[/highlight], however, take place hundreds of kilometers down in the Earth’s mantle, where high pressure makes rock so ductile that it flows instead of cracking, even under stress severe enough to deform it like putty. How can there be earthquakes at such depths?


Wadati’s work suggested that deep events occur in areas (now called Wadati-Benioff zones), where one crustal plate is forced under another and descends into the mantle. The descending rock is substantially cooler than the surrounding mantle and hence is less ductile and much more liable to fracture.

24-33 The passage suggests that which of the following must take place in order for any earthquake to occur?
I. Stress must build up
II. Cool rock must descend into the mantle.
III. A fracture must occur.
A) I only
B) II only
C) III only
D) I and III only
E) I, II and III

因為 II 屬於某些地震發生的情況Some earthquakes
題目要問你 "any" 地震的情況

[bugubugu]

In[highlight=pink] most earthquakes [/highlight]the Earth’s crust cracks like porcelain. Stress builds up until a fracture forms at a depth of a few kilometers and the crust slips to relieve the stress. [highlight=pink]Some earthquakes[/highlight], however, take place hundreds of kilometers down in the Earth’s mantle, where high pressure makes rock so ductile that it flows instead of cracking, even under stress severe enough to deform it like putty. How can there be earthquakes at such depths?


Wadati’s work suggested that deep events occur in areas (now called Wadati-Benioff zones), where one crustal plate is forced under another and descends into the mantle. The descending rock is substantially cooler than the surrounding mantle and hence is less ductile and much more liable to fracture.

24-33 The passage suggests that which of the following must take place in order for any earthquake to occur?
I. Stress must build up
II. Cool rock must descend into the mantle.
III. A fracture must occur.
A) I only
B) II only
C) III only
D) I and III only
E) I, II and III

因為 II 屬於某些地震發生的情況Some earthquakes
題目要問你 "any" 地震的情況

恍然大悟....
謝謝micht!

[styleko]

請問一下第30題
24-30 The author’s explanation of how deep events occur would be most weakened if which of the following were discovered to be true?
A) Deep events are far less common than shallow events.
B) Deep events occur in places other than where crustal plates meet.
C) Mantle rock is more ductile at a depth of several hundred kilometers than it is at 50 kilometers.
D) The speeds of both P and S waves are slightly greater than previously thought.
E) Below 650 kilometers earthquakes cease to occur.

為什麼答案是B呢？
我選C...

[stilalala]

請問一下第30題
24-30 The author’s explanation of how deep events occur would be most weakened if which of the following were discovered to be true?
A) Deep events are far less common than shallow events.
B) Deep events occur in places other than where crustal plates meet.
C) Mantle rock is more ductile at a depth of several hundred kilometers than it is at 50 kilometers.
D) The speeds of both P and S waves are slightly greater than previously thought.
E) Below 650 kilometers earthquakes cease to occur.

為什麼答案是B呢？
我選C...

我想是這句吧
Wadati’s work suggested that deep events occur in areas (now called Wadati-Benioff zones), where one crustal plate is forced under another and descends into the mantle.

原文說深層地震發生在兩個板塊交接處,

B Deep events occur in places other than where crustal plates meet.
完完全全相反,深層地震不會在(OTHER THAN)板塊交接處發生

CMantle rock is more ductile at a depth of several hundred kilometers than it is at 50 kilometers.


Some earthquakes, however, take place hundreds of kilometers down in the Earth’s mantle, where high pressure makes rock so ductile that it flows instead of cracking, even under stress severe enough to deform it like putty

跟最後一句 hence is less ductile and much more liable to fracture.

我猜你是看到最後一句了
文章一開始是說深層壓力大, SO DUCTILe所以該沒有frature才對
但最後一句說,因為兩個板塊碰撞之後,產生冷卻效應,就less ductile
所以會產生frature
這裡的less ductile是跟之前預期深層ductile相比,而不是跟淺層的比

請指教

[styleko]

了解了..
這篇文章我在模考的時候似懂非懂..因為太多生字了..
謝謝妳的回答~

[EmmaCYC]

In[highlight=pink] most earthquakes [/highlight]the Earth’s crust cracks like porcelain. Stress builds up until a fracture forms at a depth of a few kilometers and the crust slips to relieve the stress. [highlight=pink]Some earthquakes[/highlight], however, take place hundreds of kilometers down in the Earth’s mantle, where high pressure makes rock so ductile that it flows instead of cracking, even under stress severe enough to deform it like putty. How can there be earthquakes at such depths?


Wadati’s work suggested that deep events occur in areas (now called Wadati-Benioff zones), where one crustal plate is forced under another and descends into the mantle. The descending rock is substantially cooler than the surrounding mantle and hence is less ductile and much more liable to fracture.

24-33 The passage suggests that which of the following must take place in order for any earthquake to occur?
I. Stress must build up
II. Cool rock must descend into the mantle.
III. A fracture must occur.
A) I only
B) II only
C) III only
D) I and III only
E) I, II and III

因為 II 屬於某些地震發生的情況Some earthquakes
題目要問你 "any" 地震的情況

我想請問...如果這樣說
那I、III不是也只有說"Most" earthquakes
並不代表"any"阿

另外,III為什麼可以ㄚ?
因為第一段說了Some earthquakes, however, take place hundreds of kilometers down in the Earth’s mantle, where high pressure makes rock so ductile that it flows instead of cracking,
所以不是指fracture在這種情況不一定會發生阿
所以fracture "must" occur感覺有點怪怪的...

Cool rock "must" descend into the mantle=>這個只會發生在deep events所以不是"must"

所以答案為什麼不是A阿

[medi66]

"Most"的意思 就表示這是個"大多數"的情況
II 很明顯的錯誤 是在這只會發生在deep events 所以很顯然不符合 any earthquake的情況

本文第一句 是在說明一般earthquake發生時的情況 有general的概念
所以I、III 都是會發生的

個人看法 歡迎大家繼續討論~

[hcgh]

24-33
III為什麼可以ㄚ?
定位第一段
In most earthquakes the Earth’s
crust cracks like porcelain, Stress
builds up until a fracture...
所以要發生shallow earthquake一定會有stress build up的情況發生

定位第四段
The question remained: how can
(50) such quakes occur, given that mantle
rock at a depth of more than 50 kilo-
meters is too ductile to store enough
stress to fracture? Wadati’s work sug-
gested that deep events occur in areas
(55) (now called Wadati-Benioff zones)
where one crustal plate is forced under
another and descends into the mantle.
The descending rock is substantially
cooler than the surrounding mantle and
(60) hence is less ductile and much more
liable to fracture.
第四段一開始說
mantle rock非常ductile，所以不會store stress
但是Wadati發現 mantle rock會被cooler
mantle rock其實是less ductile，所以他會store stress
所以要發生deep earthquake也會有stress build up的情況發生

所以III就成立囉