Jiaqi Li, Michigan State University, East Lansing, MI, United States; Peking University, Beijing, China, Jieyuan Ning, Peking Univ, Beijing, China, Chen Cai, Washington University in St Louis, Earth and Planetary Sciences, St. Louis, MO, United States and Tiezhao Bao, ITAG Institute of Theoretical and Applied Geophysics, Peking University, Beijing, China