Jiawei Li, IGP Institute of Geophysics, China Earthquake Administration, Beijing, China, Max Wyss, Wapmerr, Bougy-Villars, Switzerland, Zhongliang Wu, Institute of Earthquake Prediction, CEA, Beijing, China, Shiyong Zhou, ITAG Institute of Theoretical and Applied Geophysics, Peking University, Beijing, China and Changsheng Jiang, Institute of Geophysics, China Earthquake Administration, Beijing, China