The main driver of plate tectonics is the movement of convecting mantle beneath the Earth's crust. This movement is primarily caused by heat from the Earth's core, which generates convection currents in the mantle. As the mantle material heats up, it becomes less dense and rises, while cooler, denser material sinks. This dynamic process drives the movement of tectonic plates, leading to various geological activities such as earthquakes, volcanoes, and the formation of mountain ranges. Plate tectonics is essential for shaping the Earth's landscape and playing a significant role in the global climate and ecosystems.