Maps of shear wave velocity anomalies in the mantle: (a) Moho–95km, (b) 95–115 km, (c) 115–135 km, (d) 135–155 km, (e) 155–175 km and (f) 175–195 km. The velocity anomalies are calculated relative to the average shear wave velocity in southern Tibet. The maps are clipped with the same procedure as in Fig. 8(d). The main tectonic boundaries and the N–S trending rifts are marked with the abbreviations as same as in Fig. 1. Locations of vertical profiles are plotted either.