They spread in all directions away from their source. They remain trapped near the source by water pressure. They travel mostly horizontally along the ocean floor. They travel mostly upward toward the surface of the water.
I gave my students this multiple choice question: An earthquake in the Earth's crust under the ocean releases sound waves. Which statement accurately describes how the sound waves spread?

Only one answer is correct among these 4 choices:
- They spread in all directions away from their source.
- They remain trapped near the source by water pressure.
- They travel mostly horizontally along the ocean floor.
- They travel mostly upward toward the surface of the water.

Could you tell me which one is correct?

They spread in all directions away from their source.