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Surface velocities derived from Global Positioning System observations and Quaternary fault slip rates measured throughout an extended region of high topography in South Asia vary smoothly over thousands of kilometers and are broadly symmetrical, with components of both north-south shortening and east-west extension relative to stable Eurasia. The observed velocity field does not contain discontinuities or steep gradients attributable to along-strike differences in collision architecture, despite the well-documented presence of a lithospheric slab beneath the Pamir but not the Tibetan Plateau. We use a modified Akaike information criterion (AICc) to show that surface velocities do not efficiently constrain 3D rheology, geometry, or force balance. Therefore, although other geophysical and geological observations may indicate the presence of mechanical or dynamic heterogeneities within the Indian-Asian collision, the surface Global Positioning System velocities contain little or no usable information about them.

Plain Language Summary Observations of tectonic velocities in the Indian-Asian collision contain little information about what is going on at depth in the region. Therefore, they cannot be used as strong constraints on models of force balance or collision architecture.