Surface Motions and Continental Deformation in the Indian Plate and the India-Eurasia Collision Zone

The collision of the Indian plate with Eurasia has played a major role in controlling the dynamics of central Asia leading to the world's largest continental deformation zone. In order to study the deformation within the Indian plate as well as the India-Eurasia collision zone, we model the lithospheric stress field by calculating the two primary sources of stress, one arising due to topography and shallow lithospheric structure estimated by gravitational potential energy differences and the other arising from basal tractions derived from density-driven mantle convection. We use several tomography models to calculate horizontal tractions using the convection code HC for two radially varying viscosity structures. We also take into account lateral viscosity variations in the lithosphere model arising from stiff cratons, weak plate boundaries, and strength variations due to old and young oceanic lithosphere. We do a quantitative comparison of our predicted deviatoric stresses, strain rates, and plate velocities with surface observables and find that the regional tomography model of Singh et al. (2014) embedded in the global S wave model S40RTS does a remarkable job of fitting the observations of GPS velocities and strain rates as well as intraplate stress field from the World Stress Map