Which dynamic force is critical for the movement of tectonic plates?

The critical dynamic force for the movement of tectonic plates is primarily related to driving forces. These forces include various mechanisms that facilitate the motion of tectonic plates, predominantly the heat generated from the Earth’s interior. This heat causes convection currents in the mantle, where hot material rises and cooler material sinks, creating a flow that acts to move the plates at the surface.

Driving forces can also include slab pull and ridge push. Slab pull occurs when an oceanic plate subducts into the mantle, pulling the rest of the plate along with it. Ridge push is the force exerted by the creation of new oceanic crust at mid-ocean ridges, pushing the plates apart.

In contrast, while shear forces and gravitational forces play roles in the stress and deformation of the plates, they do not drive the overall movement of tectonic plates as effectively as the driving forces. Heat from the core contributes to the processes described, but it is the dynamic interaction of these driving forces that is fundamental to understanding plate tectonics.