This research is to study the detail of the uppermost mantle beneath the Tibetan Plateau, the Tarim Basin and the Tien Shan using broadband, regional distance body waves. The details of the upper mantle lid, such as depth to the low-velocity zone, velocity gradient below the Moho and the lateral variability of the lid, can provide very important constraints on the dynamics of the uplift of the Tibetan Plateau. Preliminary work based on long-period body waves has shown that they can be used to constrain the velocity gradient beneath the Moho and depth to the low-velocity zone. This work will analyze the regional phases of earthquakes which have crossed the plateau and surrounding regions as recorded on the broadband Chinese Digital Seismic Network. Although the network has only been operational since mid-1986, the broadband nature of the recording allows modeling which has not been possible before. Because this involves the structure of an active seismic area, the work is a component of the National Earthquake Hazard Reduction Program.
