How do scientists use earthquake waves to determine the composition of layers of the earth?

The seismic waves are bent, sped up, or slowed down, or even reflected when they pass through the earth's layers. ... Bending of the waves occurs at the layer's boundaries. So, scientists study the path and speed of these waves through the earth to decipher boundaries and the materials that make up the layers.

Explanation:

i looked that up so dont give me credit. also seismic waves are basically the waves that are produced from earthquakes. and not like waves in an ocean itskinda like gravity waves in a way

answer biscay bay;

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