Given the task definition, example input & output, solve the new input case.
In this task, you are given a paragraph, and your task is to construct a question from the given passage. Construct question in such a way that (i) it is well explained in the paragraph, (ii) the words may/may not be present in the paragraph, (iii) it should start with what/how/describe. Avoid creating a question that (i) is just relevant to one or two sentences, and (ii) not relevant to passage. 
Example:  Magma rises from deep in the earth. The magma goes into volcanos. The volcanos pressure the magma upwards. The pressure causes the magma to push through the surface of the volcano. The lava cools. The lava forms new rock. New magma is pressured to the surface of the volcano. The volcano bursts through the rock the formed after the last eruption. 
Output:  What causes a volcano to erupt? 
The process paragraph explains in steps about - the cause for volcano eruption. The keywords in the question are relevant to the process paragraph given. So, this is a good question.

New input case for you: Fault lines appear underground. The fault lines grow over time. The rocks on each side of the fault lines rub against the rocks on the other side of the fault line. The rocks put pressure on each other. The rocks break from the pressure. The breaking of the rocks releases a lot of energy. The energy causes seismic waves. The seismic waves make the earth shake. 
Output:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
How do earthquakes occur?