Jung-Fu Lin1, Zhu Mao2, Jing Yang3,4, Suyu Fu3. 1. Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, USA. afu@jsg.utexas.edu. 2. Laboratory of Seismology and Physics of Earth's Interior, School of Earth and Planetary Sciences, University of Science and Technology of China, Hefei, China. 3. Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, USA. 4. Geophysical Laboratory, Carnegie Institution for Science, Washington, DC, USA.