GEOLOGY

Detailed explanation-1: -Seismic waves move more slowly through a liquid than a solid. Molten areas within the Earth slow down P waves and stop S waves because their shearing motion cannot be transmitted through a liquid. Partially molten areas may slow down the P waves and attenuate or weaken S waves.

Detailed explanation-2: -The speed at which seismic waves travel depends on the properties of the material that they are passing through. For example, the denser a material is, the faster a seismic wave travels (SF Table 7.1). P waves can travel through liquid and solids and gases, while S waves only travel through solids.

Detailed explanation-3: -Seismic waves tell us that the Earth’s interior consists of a series of concentric shells, with a thin outer crust, a mantle, a liquid outer core, and a solid inner core. P waves, meaning primary waves, travel fastest and thus arrive first at seismic stations. The S, or secondary, waves arrive after the P waves.

Detailed explanation-4: -Since density * increases with depth, waves speed up as they move deeper into the Earth. The change in density also causes the waves to follow curved paths as they move through the Earth. As waves travel into more dense material, they speed up and curve.

Detailed explanation-5: -How does the structure of Earth’s interior affect seismic waves. The direction and speed of waves change as they travel through different density materials. P waves can travel through solids and liquids. S waves can only travel through solids.