Answer:
Hey!
Your answer is that the wave CHANGES SPEED
Explanation:
Because of the different mediums, the earthquake waves (P-Waves and S-Waves) will get REFRACTED. REFRACTION happens when the wave SLOWS DOWN because it is moving from an area of LOWER density to an area of HIGHER density...
(OR IT COULD BE THE OTHER WAY ROUND!!)
...slowing down because there are more particles in the way preventing it from "moving" (transferring energy etc)…
