What drives the movement of tectonic plates according to plate tectonics theory?

The movement of tectonic plates is primarily driven by convection currents in the Earth's mantle.

According to the theory of plate tectonics, the Earth's lithosphere is broken into several large and small pieces known as tectonic plates. These plates float on the semi-fluid layer of the Earth's mantle, known as the asthenosphere. The primary force that drives the movement of these plates is the heat from the Earth's core, which creates convection currents in the mantle.

Convection currents are essentially the circular movement of heat energy. In the context of the Earth's mantle, the heat from the core warms up the mantle material, causing it to become less dense and rise towards the surface. As it moves away from the heat source, it cools down, becomes denser and sinks back towards the core. This circular motion of rising and sinking material creates currents that drag the overlying tectonic plates along, causing them to move.

The movement of these plates can be in different directions. Plates can move away from each other, towards each other, or slide past each other. These movements are responsible for the creation of various geographical features and phenomena such as mountains, earthquakes, and volcanic activity.

Another factor that contributes to plate movement is slab pull. This occurs when a tectonic plate with an oceanic crust cools down, becomes denser than the underlying asthenosphere, and sinks into the mantle at a subduction zone. The sinking plate pulls the rest of the plate along with it, contributing to its movement.

In summary, the movement of tectonic plates is a complex process driven primarily by convection currents in the Earth's mantle, with additional contribution from slab pull at subduction zones. This movement is responsible for the dynamic nature of the Earth's surface, leading to the creation and destruction of various geographical features.