Part of the motion of a tectonic plate caused by its subduction
Slab pull is ageophysical mechanism whereby the cooling and subsequent densifying of asubductingtectonic plate produces a downward force along the rest of the plate. In 1975 Forsyth and Uyeda used theinverse theory method to show that, of the many forces likely to be driving plate motion, slab pull was the strongest.[1] Plate motion is partly driven by the weight of cold, dense plates sinking into themantle atoceanic trenches.[2][3] This force andslab suction account for almost all of the force drivingplate tectonics. Theridge push at rifts contributes only 5 to 10%.[4]
Carlson et al. (1983)[5] in Lallemand et al. (2005)[6] defined theslab pull force as:
Where:
K is4.2g (gravitational acceleration = 9.81 m/s2) according to McNutt (1984);[7]
Δρ = 80 kg/m3 is the mean density difference between the slab and the surrounding asthenosphere;
L is the slab length calculated only for the part above 670 km (the upper/lower mantle boundary);
^Carlson, R. L.; Hilde, T. W. C.; Uyeda, S. (1983). "The driving mechanism of plate tectonics: Relation to age of the lithosphere at trenches".Geophysical Research Letters.10 (4):297–300.Bibcode:1983GeoRL..10..297C.doi:10.1029/GL010i004p00297.
