Question

which two phrases describe the location where the vibrations of an earthquake are the strongest?

a. the point where the rock breaks underground
b. the point on earths surface directly above where the rock breaks
c. the epicenter
d. the focus

Explanation:

The focus is the point where the rock breaks underground (the source of the earthquake). The vibrations spread out from the focus. The epicenter is the point on Earth's surface directly above the focus. The vibrations are strongest at the focus and its corresponding epicenter.

Answer:

A. The point where the rock breaks underground, C. The epicenter