Why do tectonic plates move?

Tectonic plates move because they are floating on top of the liquid mantle. The mantle itself moves due to convection currents: hot rock rises, gives off some heat, then falls. This creates vast swirls of moving liquid rock under the crust of the earth, which jostles the plates of crust on top. read more

Tectonic plates comprise of crust and upper mantle rock. The upper mantle rock is less dense than the denser mantle. The increase and decrease of convection currents in the mantle result in slow progressive movement in the plates. read more

The main driving force of plate tectonics is gravity. If a plate with oceanic lithosphere meets another plate, the dense oceanic lithosphere dives beneath the other plate and sinks into the mantle: this process is called subduction. read more