One of you fellows got the answer correct. Friction. It is well known that the Earth's axis has a wobble which shifts the entire mass of the Earth each day. In effect the wobble causes a shaking of the Earth's mass which keeps the crust flexing resulting in Earth quakes and volcanoes and the...
The Earth's rotation has a wobble as most everyone knows. The huge mass of the Earth is being shaken as a result of the wobble which causes molecular fristion which produces large amounts of heat. The wobble also causes shifting of the Earth's crust. The symptoms of the shifting crust are...