What observation supports the hypothesis that the slab-pull force is the primary cause of plate motion?
A) Divergent plate boundaries represent all of the upwelling expected by mantle convection.
B) Plumes are the deep upwelling component of convection with seismically slow velocities.
C) Earthquakes and volcanoes are concentrated at plate boundaries.
D) Plates with long subduction zones move faster than plates with short subduction-zones.

Question

Quizplus · Accepted Answer

This observation supports the hypothesis that the slab-pull force is the primary cause of plate motion because plates with longer subduction zones experience stronger slab-pull forces, and therefore move faster, than plates with shorter subduction zones. This relationship between subduction zones and plate motion is consistent with the idea that the weight of subducting slabs exerts a gravitational pull that drives plate motion.

What Observation Supports the Hypothesis That the Slab-Pull Force Is