I have constructed a high resolution P-wave tomographic model of the upper mantle structure beneath East Asia and the Tibetan Plateau. The new model reveals that the mantle structure associated with the Indian subduction varies considerably along the strike of the collision zone. From west to east, the dip angle of Indian subduction increases and the distance over which the plate underthrusts the Tibetan Plateau decreases. The eastward retreating slabs of western Pacific and Phillipine plates are deflected in the transition zone beneath the Korea, Japan Sea, and East China. Some of Mesozoic subducted slabs have reached as far west as 110oE longitude under the Yangtze Craton. Precambrian continental roots under Ordos block and Sichuan Basin, which extend to 250~300 km depth, may form a boundary of transition in tectonic regimes from the India-Eurasia collision control in the southwest to Pacific, Philippine Sea, and Java-Sumatra subductions control in the east and southeast. I conclude that the (direct) influence of the India-Eurasia collision on the tectonic evolution of East Asia may be confined to the Tibetan plateau and vicinity, whereas the tectonic development of a large area east and southeast of Ordos, Sichuan and Burma is driven by the stress field and 3-D upper mantle processes associated with subductions of Pacific, Philippine Sea, and Indo-Australia plates.

Indian subducted lithosphere beneath Tibet