Contents of 8.2 How do earthquakes help make images of Earth's interior?

$cut away drawing of the earth to show how P waves are refracted through the core.$

Fig 8.15

8.2 How do earthquakes help make images of Earth's interior?

Shadow zones are areas where seismometers do not record P or S waves (or both). The reason for

this is that P waves are refracted through core & mantle boundaries, and

S waves are blocked by the liquid outer core entirely.