1. Subduction: When two tectonic plates collide, one denser plate (usually oceanic) slides beneath the other (either oceanic or continental). This process is called subduction.
2. Slab Descent: As the subducting plate descends into the mantle, it gets pulled down by gravity. This downward force is known as slab pull.
3. Melting: As the subducting slab descends deeper into the mantle, the increasing pressure and heat cause it to melt. This molten rock, called magma, is less dense than the surrounding mantle and rises to the surface, often erupting as volcanoes.
4. Convection: The process of melting and rising magma creates convection currents in the mantle. These currents contribute to the overall movement of tectonic plates.
In summary, slab pull is the main driving force behind plate movement. It occurs because of the gravitational pull on the dense, subducting plate, which ultimately melts and contributes to the ongoing cycle of tectonic activity.
