GED Science TestEarth and Space ScienceMedium
A geophysicist is analyzing seismic wave data from an earthquake. She observes that S-waves are unable to pass through a specific layer deep within the Earth. This observation provides key evidence about the state of matter of which Earth layer?
- AInner Core
- BCrust
- COuter Core
- DMantle
Show answer & explanationAnswer & explanation
Correct answer: C. Outer Core
S-waves (shear waves) can only travel through solids, not liquids or gases. The observation that S-waves cannot pass through the outer core indicates that this layer is liquid, providing crucial evidence for its composition.
Why the other options are wrong
- A. The inner core is solid, and S-waves can travel through it.
- B. The crust is solid and S-waves travel through it.
- D. The mantle is primarily solid, though ductile, and S-waves travel through it.
S-wave Behavior
S-waves (shear waves) are a type of seismic wave that can only propagate through solid materials, providing evidence for the state of matter of Earth's interior layers.
- Cannot travel through liquids or gases
- Used to determine the liquid nature of the outer core
- Travel slower than P-waves
Memory trick: S-waves: Solids only, no swimming in the core!