The thermal-mechanical stability of the lithosphere-mantle system ultimately depends on the nonlinear interaction of the tectonic forces and the responses elicited from the nonlinear temperature-and strain-rate dependent rheology. In this two-year project the P. I. plans to study creep instabilities in both the oceanic and continental lithospheres, which have either an elasto-visco plastic or a viscoelastic rheology with realistic creep parameters. He will also study critical factors that maintain the integrity of slabs. All of these problems are rich in non-linearity and promise surprising but fundamental results, which should help to elucidate the critical character of lithospheric and mantle dynamics in the parameter range relevant to geological systems.
