Question

How do geologists use seismic waves to learn about the Earth’s interior?

Answer 1

They detect s waves from using certain instruments and thus seismic waves are used

Answer 2

Seismic waves travel through different materials inside the Earth at different speeds. They also get bent when they pass from one kind of material to another. By observing the path and speed of seismic wave, scientists can find out the types and arrangement of the materials through which it passed. Hence, from such observations we today have three layers of Earth - crust, mantle and core.