PrepTest 151, Section 1, Question 27

Working the answers

• A

  Considerable movement relative to the mantle occurs in the same-direction collision described for quiet zones. Those plates can collide and undergo subduction without frequent earthquakes. Motion and collision alone don't establish the frequent activity A promises.

• B

  The explanation discusses the size of the contact area, not the probability of an earthquake at every location within it. An earthquake might be more likely near an end or in the middle; we aren't given that comparison. A larger contact area doesn't imply equal likelihood at each point.

• C

  The opening does describe energy building up and being released in earthquakes. But it doesn't say quiet zones are especially dangerous because they accumulate energy slowly for an infrequent release. Their relative quiet is explained through reduced contact and friction. C attaches a new risk story to those zones.

• D

  The quiet subduction zones directly contradict this requirement. We are explicitly told that subduction occurs in places with little or no seismic activity. Earthquakes aren't required for those regions to be identified as subduction zones.

• E
  Correct

  Shallow descent leaves a larger area of contact, where the plates resist each other like sheets of sandpaper. That resistance creates earthquake-producing friction. The contact-to-friction connection supports the greater likelihood of earthquakes; it doesn't require every collision to cause one.