【摘要】 以拉萨地块中段铁路沿线GPS局域网2005—2007年高精度观测资料为依据,结合区域活动断裂构造、地形地貌特点和历史强震活动,研究了拉萨地块中段铁路沿线活动构造区域现今地壳运动变形与主要断裂活动的一些特征。初步结果显示:1)研究区现今水平运动速度方向呈北东-北东东向,与印度板块向北碰撞引起青藏高原总体运动背景一致,反映了现今地壳受到近南北方向水平挤压和物质向东流动双重水平动力的联合作用;2)区域视应变分布表现出不同地段变形方式的差异,与地壳伸展变形方式存在密切关系,反映了新构造时期以来盆地的拉张伸展变形与山地受压隆起的"盆-山"构造活动分异;3)区内北西-北西西向展布的F76、F67、F503条断裂活动速率自南向北递减明显,其与北东-北北东走向的断裂F73、F65交汇部位及其附近的视应变高值分布区中,历史地震活动非常强烈,反映了构造活动变形的继承性。更多还原

【Abstract】 On the basis of the GPS measurement data in 2005—2007 along the railway in central Lhasa block,combining with the parameters of regional active faults and topographic-geomorphic character and historical strong earthquake,the characteristics of present-day crustal movement and deformation and main fault activity along the railway in the middle of Lhasa block are analyzed.The conclusions are drawn as follows.1)The present-day horizontal movement direction of the studied area is WE-NEE,consistent with the Tibetan plateau movement background by the northward collision of the India block that reflects the joint action of the horizontal dynamics from both the north-southward horizontal compression and the eastward matter flow.2)The regional apparent strain distribution manifests itself in the different mode in different zone that closely related to the crust extension deformation made and reflects the divergence of the basin extension deformation with the ’basin-mountain’ tectonic activity of pressed and rise mountainous region.3)Active velocities of the faults:F76,F67 and F50 evidently descent from S to N,in the spaces that they intersect with the NE-NNE faults F73 and F65 and their adjant area of high apparent strain distribution the historical seismic activity was very strong it reflects the inherit of tectonic activity and deformation.更多还原