Implications of crustal property variations for models of Tibetan plateau evolution

Shear-coupled teleseismic P waves sampling the interior of the Tibetan plateau provide evidence of systematic variations in crustal structure. The crust thins by up to 20 km from south to north with a concomitant increase in Poisson's ratio from normal values in the south to unusually high values in the north. This suggests that the crust of the northern plateau is partially melted due to high temperatures. These changes imply spatial and perhaps temporal variations in the way the elevation of the high plateau is created and maintained.