摘要：The Sichuan-Yunnan region are divided by 9 activesecondary crustal blocks based on several GPS repeatsurveys of more than 200 GPS sites during 1999-2005.Velocity of the 9 secondary blocks are calculated andanalyzed as well as the strain field of the arearelated with Sumatra-Andaman Earthquake of 2004.Results indicate the crustal movement of the area innorth and west are stronger than that of south andeast. The motion of Sichuan-Yunnan rhombic block isdominated by clockwise rotation. The velocity ofthose blocks excluded from rhombic block decreasedswiftly. The eastward extrusion of the Tibetanplateau presents a remarkable drop in the middle-Yunnan block and the absorption effects of Lijiang-Xiaojinhe fault is visible compared with the earlyGPS results from 1998 to 2002. The strain convergenceappeared at Lancangjiang of Yunnan province implies apossible moderate seismic risk.
