Mountain building by continent-continent collision is the most important orogenic process on Earth whose mechanism is not well understood. The collision between India and Asia is the largest region of such collision and has produced the world's most spectacular topography. Within this region, the Tibetan Plateau stands out as a natural laboratory in which we can test hypotheses regarding a fundamental process that has impacted continental dynamics. Collision models, obtained in various studies, predict significantly different upper-mantle structure beneath the plateau. The upper mantle, therefore, holds a key to differentiating between possible collisional models and to unraveling how this archetype of plateaus came into being. The objective of this research is to determine high resolution 3-D upper-mantle P and S velocity structure beneath the Tibetan Plateau and neighboring regions. The PIs will collect and process available seismic waveform data of more than 300 broadband stations in the study area from earthquakes in the upper-mantle distance range. These studies should provide much improved lateral and depth resolution in the upper mantle than it has been possible in all previous studies. The results of the proposed study can be used to verify or dismiss existing collision models and to develop new ones. The research topic is also closely related to several undergraduate and graduate courses (plate tectonics and geodynamics) that the PI is currently developing and teaching at SLU. The proposed research involves collaboration between Saint Louis University and the Institute of Geophysics, Chinese Earthquake Administration. It will use seismic data collected by several multi-national (China, France, Germany, USA, etc) projects in Tibet.
