Current Deformation in the Tibetan Plateau: A Stress Gauge in the India‐Asia Collision Tectonics.

Geodetic velocities and mantle seismic anisotropy provide relevant constraints to the dynamics of the Asian continent. Here, these are compared to numerical models of subduction, collision, and upper plate deformation, developing features similar to the present‐day India‐Asia region. Varying buoyancy and far‐field forces, the models provide coupled surface and mantle motions and deformation allowing a first‐order agreement to the observables in the Tibetan area. Observed trends are reproduced when the pull from the Indian slab vanishes and the neighboring southeast Asian slab drives extrusion in eastern Tibet, matching GPS rotation and convergence‐perpendicular component, and a far‐field force acts to increase the GPS convergence‐parallel component and lithospheric thickening observed in the Tian Shan‐Tibetan domain. The net force exerted on the Tibetan lithosphere is ~2.6 × 1012 N/m, mostly due to neighboring southeast Asian subduction, and raises to ~2.8 × 1012 N/m, when additional far‐field forces apply. Largest suction force exerted on the Sunda margin is ~2.4 × 1012 N/m, whereas the comparison to seismic anisotropy supports the idea that the mantle is passive. These are interpreted in the context of the differential along‐strike dynamics of the Indian‐southeast Asian subduction: The coupled indentation‐suction along the plate margin drives large‐scale extrusion, while the excess stress along the Indian margin is accommodated by Tibetan lithospheric thickening. The models constrain the boundary forces and lithospheric processes of the Asian tectonics and emphasize the role of large‐scale coupling of the Indian margin and the southeast Asian subduction. Key Points: Varying boundary forces in subduction models provide continental motions and deformation and mantle shearing end‐membersThese are compared to Tibetan Plateau GPS motions and seismic anisotropy in the India‐Asia regionThe match to observables constrains the boundary forces acting along the subduction margin [ABSTRACT FROM AUTHOR]