Can someone elaborate on the difference of choice (A) and (B), I sensed that (B) is better, but why is (A) wrong?
Thanks
ohthatpatrick Wrote:Main Point = Topic + Purpose
The topic is the relationship between earthquakes / subduction zones / types of plate collision.
The purpose is to present the NEW scientific understanding of this issue, to ANSWER a question.
The Main point / purpose is usually hanging around the first big pivot in the 1st paragraph:
BUT, YET, HOWEVER, RECENTLY
We can surmise this purpose from key rhetorical moments in the 1st paragraph:
"According to the generally accepted theory of plate tectonics ...."
"Contrary to expectations, however ..."
"There remained a crucial question for which we had no answer, until recently ..."
"One group now proposes that .."
So if the purpose is answering the question "how is it that you can have lots of subduction, but not a lot of quakes?", then the main point is the answer:
"if the plates collide when one is chasing the other, the subduction angle is steep, so there's not much friction, so there's not many earthquakes".
(A) The amount of subduction is NOT strongly correlated with number of quakes. The whole riddle we're solving is based on this mismatch "often, there's lots of subduction where there are lots of quakes. But there are these other curious regions with lots of subduction and not many quakes."
(B) Yes, this speaks to how we answered the question posed at the end of the first paragraph.
(C) Wrong, the plates DO collide, they just do so in a way that causes a steep, low-friction subduction.
(D) "ABANDONS" is too strong. We still think the process of subduction is what results in earthquakes, but we're more specifically refining that to "shallow angle subduction is what results in earthquakes".
(E) The theory isn't threatened. We were just trying to figure out one weird anomaly within the theory, and we did.
JenniferK632 Wrote:Hi! Would you be able to explain why the theory isn't threatened? If, like the last paragraph says, that the original theory ignored the potential of low subduction earthquakes, wouldn't that threaten the correctness of the original theory?