jgg     2012 32 (6):  54-58    ISSN: 0412-1961  CN: 21-1139/TG PRELIMINARY SORT OF REPEATED GRAVITY DATA IN NORTH CHINA AREA Hao Hongtao 1,2,3) ;Li Hui 1,2) ; and Sun Shaoan 1,2) 1)Key Laboratory of Earthquake Geodesy,Institute of Seismology, CEA, Wuhan 30071;2)Wuhan Base for Institute of Crastal Dynamics,CEA,Wuhan 430071;3)Graduate School of Chinese Academy of Science, Beijing 100039 Received: 1900-01-01  Revised: 1900-01-01  Online: null Supporting info null