Quantifying the net slab pull force as a driving mechanism for plate tectonics

Abstract

It has remained unclear how much of the negative buoyancy force of the slab (FB) is used to pull the trailing plate at the surface into the mantle. Here I present three-dimensional laboratory experiments to quantify the net slab pull force (FNSP) with respect to FB during subduction. Results show that FNSP increases with increasing slab length and dip up to ∼8-12% of FB, making FNSP up to twice as large as the ridge push force. The remainder of FB is primarily used to drive rollback-induced mantle flow (∼70%), to bend the subducting plate at the trench (∼15-30%) and to overcome shear resistance between slab and mantle (0-8%).