“slab pull” is a type of tectonic plate movement that occurs due to the forces of mantle convection and results in the subduction of the lithosphere, causing
earthquakes.
rift valleys.
ocean trenches.
mid-ocean ridges.

Slab pull” is a type of tectonic plate movement that occurs due to the forces of mantle convection and results in the subduction of the lithosphere, causing earthquakes. Slab pulls are actually portions of the motions of a tectonic plate that accounts for its subduction. The motion of these plates are driven by weight of cold and denser plates that sink at trenches towards the mantle of the Earth. 

Ansradar; im guessing here; good luck : )