求助，GWD-24 33

zhanhualv

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?

skigorush

頂

lupisces

我选D这样是不是矛盾了 ？

where high pressure makes rock so ductile that it flows
            instead of (10) cracking, even under stress severe enough to
                deform it
            like putty

最后一段 too ductile to store enough stress to fracture? 太ductile以至于不可能store 足够的压力导致fracture  这里也说明没导致fracture

much more liable to fracture.更可能fracture而已，怎么能说fracture呢？

退一步说，即使有的deep events导致了fracture，也不能说明所有的都导致啊，我觉得定位还是应该在第一段

阿土莎莎

up

阿土莎莎

up

wingkim

为何此题没人选C？？

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

In most earthquakes the Earth’s

crust cracks like porcelain, Stress

builds up until a fracture forms at a

line depth of a few kilometers and the crust

(5) slips to relieve the stress. Some            （转折提出另外的情况）

   earthquakes, however, take place hun-

   dreds of kilometers down in the Earth’s

   mantle, where high pressure makes

   rock so ductile that it flows instead of

(10) cracking, even under stress severe

enough to deform it like putty.

 

 

                                Wadati’s work sug-       （推测解释）

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.

见颜色对应部分，题目问的是任意的地震，

第一种地震（蓝色）只是most earthquake需要stress以致产生fracture，那么就是most earthquake需要fracture；

第二种地震（粉红色）some earthquake——deep events是hence is less ductile and much more liable to fracture

所以两种地震都需要fracture，对应题目“any earthquake”。

但是由红字部分可见，第二种地震根本上不存在需要stress，第10行只是假设的在那样的深度下，岩石将会受到极其大的压力而变成流体，且第60行已经明确表明与第10行相反的事实，通篇都没有提到第二种地震需要stress的条件。

求教了。

[此贴子已经被作者于2007-11-16 18:20:48编辑过]

tangzimo

破题，绕了半天，第二种地震也还是fracture了……

晴天小狗

为什么是D啊？

请讲讲

MaccMichAA

The descending rock is substantially cooler "不等于"  Cool rock must descend into the mantle？