Main layers of the Earth are:
The crust is too thick to drill through, the deepest mine only goes up to 3.5km deep. So information is used from seismic waves. Seismic waves are produced by earthquakes or explosions.
Lithosphere is crust and the upper mantle. It is broken into huge parts called tectonic plates. Tectonic plates float on mantle because they are less dense. Tectonic plates move very slowly.
Earthquakes occur due to the movements of tectonic plates.
Volcanic Activity happens…