Waves and Optics
Seismic Waves
To compare seismic waves and explain how they provide evidence about the structure of the Earth.
What you will learn
How P-waves and S-waves move through the Earth
Why P-waves and S-waves travel differently
Which seismic waves can pass through liquids
How seismic waves reveal Earth’s internal layers
How to interpret evidence from earthquake waves
Explanation
Earthquakes produce P-waves, which are longitudinal, and S-waves, which are transverse. P-waves travel through solids and liquids; S-waves cannot travel through liquids. Arrival patterns, speeds, refraction and missing S-waves provide evidence about Earth’s hidden interior, including a liquid outer core. Example: Explain why missing S-waves can indicate liquid material. S-waves cannot propagate through a liquid, so their absence constrains the path’s material. State assumptions. Apply the model.