What geological process causes the movement of tectonic plates?

The movement of tectonic plates is primarily driven by intense heat from the Earth's core. This heat causes convection currents in the semi-fluid layer of the mantle beneath the Earth's crust. As the mantle material heats up, it becomes less dense and rises towards the surface. When it cools, it becomes denser and sinks back down. This cyclical movement creates forces that drive the plates at the surface of the Earth, leading to their movement.

The intense heat results from the decay of radioactive elements and residual heat from the planet's formation, contributing to the thermal energy that fuels mantle convection. This process not only drives the movement of tectonic plates but also results in geological phenomena such as earthquakes, volcanic activity, and the formation of mountain ranges. Understanding this mechanism is fundamental to the study of plate tectonics and geological processes on Earth.