The wavelength of a wave is measured from crest to crest. Waves travel uniformly outward from the wave source. The frequency of waves varies in different mediums. Waves move at the same speed in different materials.
I gave my students this multiple choice question: Seismic waves occur as a result of an earthquake. Which statement describes a wave property that makes it possible for scientists to locate the source of an earthquake?

Only one answer is correct among these 4 choices:
- The wavelength of a wave is measured from crest to crest.
- Waves travel uniformly outward from the wave source.
- The frequency of waves varies in different mediums.
- Waves move at the same speed in different materials.

Could you tell me which one is correct?

Waves travel uniformly outward from the wave source.