What is slabpull?

Answer 1

Slab Pull Force occurs when a denser oceanic plate is forced beneath a less dense continental plate or oceanic plate in a process called subduction.

It's the force caused by suction of the cold dense lithosphere into the asthenosphere at destructive margins. Basically, because lithosphere is denser than asthenosphere, there is gravitational imbalance which is passed on to the crust. this causes the lithosphere to be sucked inwards at the oceanic trenches into deep asthenosphere.

Answer 2

an old oceanic lithosphere is denser than the asthenosphere the edge of the tectonic plates that contains oceanic lithosphere sinks and pulls the rest of the tectonic plate with it in a process called slab pull

Answer 3

Slab pull is the force that pulls a tectonic plate along the top of the asthenosphere due to its greater density compared to the underlying mantle. As a result, subducting oceanic plates can contribute to the movement of tectonic plates and drive plate tectonics.