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

[1] It has remained unclear how much of the negative buoyancy force of the slab (F-B) 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 (F-NSP) with respect to FB during subduction. Results show that FNSP increases with increasing slab length and dip up to similar to8-12% of F-B, making F-NSP up to twice as large as the ridge push force. The remainder of FB is primarily used to drive rollback-induced mantle flow (similar to70%), to bend the subducting plate at the trench (similar to15-30%) and to overcome shear resistance between slab and mantle (0-8%).