How are earthquake waves used to provide information about earth's interior?

Scientists analyze the speed, direction, and strength of earthquake waves as they travel through Earth's interior to determine the composition, density, and structure of the layers. Different types of seismic waves (P-waves and S-waves) travel at different speeds and are affected by the various materials they pass through, helping scientists create models of the Earth's interior. This information helps us understand the planet's structure and composition.