Abstract: Leveling measurements in 1979 and 2002 along Golmud-Wudaoliang level line reveal that: (1)The Eastern Kunlun Fault zone and Hoh Xil block are continuing their inherited upwarping process relative to Qaidam basin.During the period of 1979 to 2001,the peak of Eastern Kunlun Mountains at the Kunlun Mountains Pass was uplifted about280mm in maximum at a rate of 15mm/yr with respect to Golmud,and Wudaoliang was uplifted about210mm at a rate of 10mm/yr with respect to Golmud during the same period. (2)The Hoh Xil block between the Kunlun Mountains and Wudaoliang upwarped zone,was uplifted at a rate of7mm/yr relative to Golmud,and subsided at a rate of 3～7mm/yr relative to the Kunlun Mountains and Wudaoliang upwarped zone. (3)The vertical deformation of Golmud-Wudaoliang profile conforms on the whole to the subduction-overthrust crustal thickening model for the Tibetan Plateau,while the overthrust movements along Xidatan-dongdatan,mid-Kunlun and north-Kunlun Faults constitute the most part of the recent uplift of the Eastern Kunlun Fault zone.The weakening of overthrust movement from southern Kunlun region to northern Kunlun margin can also be clearly recognized.(4)Geological investigations show that along the 350km-long left-lateral rupture zone of the Kunlun M_S 8.1 earthquake of November 14,2001,there exist several slip segments with different left-lateral displacements,among which the maximum may reach6m,and the minimum is only 2m.Theoretical calculation based on Okada (1985) dislocation model demonstrates that uneven left-lateral displacements of the Kunlun earthquake fault might cause differential vertical deformation up to 100mm or more across the rupture zone near the Kunlun Mountain Pass.Abnormal uplift of the Xidatan fault valley and abnormal subsidence of the Kunlun summit near the Kunlun Mountain Pass are both closely related to the uneven left-lateral slip of the Kunlun seismic fault zone.

Key words: Eastern Kunlun Fault zone, earthquake, vertical deformation, subduction-overthrust

摘要： 沿格尔木—五道梁公路测线1979,2001年的2期水准观测资料表明:1)东昆仑山及可可西里地区现今相对于柴达木盆地仍在发生继承性的隆升运动。1979—2001年期间,昆仑山口主峰一带相对于格尔木约上升了280mm,上升速率高达15mm/a;五道梁相对于格尔木上升了约210mm,上升速率约10mm/a。2)昆仑山口至五道梁之间的可可西里地区,在相对于柴达木盆地以7mm/a的速度整体抬升的同时,还相对于南、北两侧的五道梁和昆仑山隆起区以3～7mm/a的速度下沉。3)格尔木—五道梁剖面垂直形变整体符合俯冲 -逆掩地壳增厚模式,其中,沿西大滩断裂、中昆仑山断裂和昆仑山北缘断裂带的逆冲推覆运动,占了整个东昆仑山现今构造隆起的大部分,其逆冲推覆运动有自南向北衰减的特点。4)地质调查结果表明,沿2001年11月14日昆仑山口西M_S8.1地震350km的左旋破裂带,可以划分出若干个不均匀错动段,错动量最大可达6m,最小只有2m。基于Okada(1985)位错模型的理论计算结果表明,地震断层不均匀左旋错动可以在昆仑山口破裂带南北两侧产生100多毫米的差异性垂直位移。1979—2002年实测垂直位移中,西大滩断裂谷地水准点的异常上升、昆仑山口测点的异常下降等都与发震断层的不均匀错动密切相关。

关键词: 东昆仑山断裂带, 地震, 垂直形变, 俯冲-逆掩