jgg     2007 27 (5):  99-102    ISSN: 0412-1961  CN: 21-1139/TG CHANGES OF LOCAL GRAVITY FIELD BEFORE AND AFTERSECOND IMPOUNDMENT IN THREE GORGES DAM AREA Sun Shaoan 1，2) ; Xiang Aiming 1，2) ;Xu Rugang 1，2) ;Zhang Xinglin 1，2) ; and Wei Jin 1，2) 1) Institute of Seismology, CEA, Wuhan 430071 2) Crustal Movement Laboratory, Wuhan 430071 Received: 1900-01-01  Revised: 1900-01-01  Online: null Supporting info null