- the large shadow zone for the S waves on the opposite side of the earth from the
- the two smaller shadow zones for P waves.
Note that there is a considerable change in density from the solid mantle to the liquid
|Consider a P wave at the point A where it just enters the liquid outer
core at a very small angle. |
|This wave experiences a large increase in refraction and undergoes a significant change
in direction at this interface.|
|Again when this wave leaves the outer core back into the mantle there is a change in
|This wave gives the extent of the P wave shadow zone.|
By finding the angles at which the P and S waves both disappear we can
calculate the radius of the liquid core of the earth.