Generally, the movements in the Earth’s interior occur in the upper layer of the mantle Tremendous energy is released by radioactive materials present here. This leads to a sudden movement in form of volcanic eruptions where hot solid, liquid and gaseous materials are forcefully thrown out from the mantle of the Earth, onto the surface of the Earth. This causes a lot of instability within the crust of the Earth which would also lead to the release of pressure in the form of seismic waves or tremors causing earthquakes.
