We appreciate the support of the China State Scholarship Fund, the Natural Science
Foundation of China (41074087, 41174100), the Fundamental Research Funds for the Central Universities(11CX06002A). We thank KAUST and the Texas Consortium for Computational Seismology (TCCS) for partial financial support. We also thank all developers of the Madagascar open-source software package (http://ahay.org). We thank TACC (Texas Advanced Computing Center) for providing supercomputing resources used in this study.