1. Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, 19 Beitucheng West Road, Chaoyang District, Beijing 100029, China, zhaolf@mail.iggcas.ac.cnhexi@mail.iggcas.ac.cnyaozx@mail.iggcas.ac.cn
2. Also at College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
3. Institute of Geophysics and Planetary Physics, University of California at Santa Cruz, 1156 High Street, Santa Cruz, California 95064 U.S.A., xxie@ucsc.eduyaozx@mail.iggcas.ac.cn