Overall, the maximum effective tectonic force available for lithospheric deformation is of the order of a few 10¹³ Nm^-1. This force must be able to double the thickness of the continental crust, to account for Tibet -the highest and largest plateau on Earth, and to sustain the gravitational force associated with this thickening and with mountain belts at the edge of continents (e.g. the Andes).

Averaged over a lithospheric thickness of 100 to 200 km, the maximum differential stress available to deform the Earth lithospheres is in the range 100-500 MPa. This places some constraints on the rheology of Earth material.

Taboche and Khumbu Valley in 2007/ Photo credit: Alton Byers/ The Mountain Institute