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利用青藏块体及其周边地区1991～2000年间的GPS观测获得的地壳水平运动速度场资料,1998,2000年重力复测资料,初步研究了昆仑山口西M_s 8.1级地震前的区域构造变形背景。分析表明,这一大地震的孕育、发生与大区域的水平运动和变形背景有关,可能是较大尺度的地块活动行为,青藏块体内部左旋剪切变形区的范围很大,这次大地震正好发生在与断裂走向一致的左旋剪切应变率量值最高的区域和面膨胀应变的张性区,重力变化的负值异常区的边缘,区域构造变形背景有利于大型左旋走滑破裂的发育。
Based on the horizontal crustal velocity data obtained from GPS observations during 1991 ~ 2000 in Qinghai-Tibet block and its surrounding areas and the gravity retest data in 1998 and 2000, the regional tectonic deformation background before the M_s MS 8.1 Kunlun Mountain Pass was studied. The analysis shows that the occurrence and occurrence of this major earthquake is related to the horizontal movement and deformation background in a large area and may be the activity of larger scale. The range of left-lateral shear deformation in the Qinghai-Tibet block is very large. The earthquakes happen exactly in the region of the highest magnitude of left-lateral shear strain rate and the extensional strain of extensional strain, the edge of the negative anomaly region of gravity change, and the regional tectonic deformation background is favorable for large-scale left-lateral strike-slip rupture development.