The main reason that deep P and S seismic waves do not travel in straight lines inside Earth is that
A) Earth is spherical,and the waves follow the shape of the surface of Earth.
B) they cannot travel through molten regions,and thus reflect back toward the surface of Earth.
C) they reflect and scatter off numerous irregularities and faults inside Earth.
D) their speed changes with changing density,causing the waves to refract.

Question

Quizplus · Accepted Answer

The speed of seismic waves changes with the density of the material through which they are traveling. This causes the waves to refract, or bend, as they pass through different layers of Earth's interior. This refracting can cause the waves to travel along curved paths, rather than straight lines. While the other choices may be factors that affect the behavior of seismic waves, they do not fully explain why the waves do not travel in straight lines.

The Main Reason That Deep P and S Seismic Waves