【摘要】 2010年4月14日青海省玉树发生MS7.1地震后,中国地震局及时组织实施了地震科学考察,其中对玉树、西宁、姑咱和西昌等4个绝对重力点进行复测,通过比对前期成果,分别给出了2007年以来(地震前后)3～4期各测点H=1.0m(距墩面高)和H=0.0m(墩面)处的绝对重力变化(观测精度均优于3.0×10-8 m.s-2).结合已有区域地质构造运动、地震活动机制、形变测量成果等,主要结论或认识有:1)地震前后(含同震)玉树、姑咱、西昌绝对重力变化明显呈上升变化,玉树点和姑咱点尤为突出;2)同震模拟结果表明,地震前后玉树点绝对重力变化(H=1.0m)与同震破裂效应基本相当;3)从重力变化角度检核了玉树地震左旋破裂运动对羌塘块体东流运动和川滇菱形块体的南东-南南东运动具有明显激励作用,川滇菱形块体北段尤为强烈,南段可能因南南东向运动遇到中部贡嘎山隆起的阻挡吸收而有所减弱.更多还原

【Abstract】 After the Yushu MS 7.1 earthquake on April 14 th,2010,an earthquake scientific investigation have been executed immediately by China Earthquake Administration.Four absolute gravity stations including Yushu,Xining,Guzan and Xichang have been surveyed.Comparing with previous results,we provide 3 or 4 periods of absolute gravity observation results before and after the earthquake with the precision better than 3.0×10-8 m·s-2,and the results include two cases which are H=1.0 m(height above earth surface to surveying point) and H=0.0 m(earth surface).Considering the local tectonic movement,seismic activity,deformation measurement results and so on,the main conclusion in this paper include: 1)The absolute gravity changes of Yushu,Guzan and Xichang before and after the earthquake are increasing,especially the Yushu and Guzan stations.2)The coseismic simulation results indicate that it’s nearly equivalent between the Yushu absolute gravity changes(H=1.0 m) and coseismic rupture effects.3)On the point of view of gravity changes,the left lateral rupture movement of the Yushu earthquake have obvious invigorative effect to the eastward mass flow of Qiangtang block and the southeast-and-south-south-east movement of the Sichuan-Yunnan rhombic block.It’s especially intense in the north part of the Sichuan-Yunnan rhombic block,and weakened in the south part,which may caused by the block off Gongga mountain uplift when moving to the south-south-east.更多还原