Mapping Earths layers with seismic waves
P, S and L (Love) waves can be used to construct a three dimensional image of the interior of Earth as the waves refract around and travel through various layers.
S waves can only travel through a solid, so the liquid part of the core creates a large shadow zone, as they are unable to travel through large parts of the Earth’s core.
P waves get refracted, or bent, as they travel through materials of different densities, such as a liquid layer. They then bend again when they enter the next layer, causing shadow zones on the far side of the earth.
By mapping the location of these shadow zones for a known epicentre location, seismologists have mapped the layers of the Earth.
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