乌恰伽师地区GPS地壳运动监测网研究
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摘要
通过对乌恰、伽师地区GPS监测网进行的6期复测,结合周边地区的IGS站数据,计算得到了该区50多个GPS点位在ITRF2000下的最新运动速率及相对欧亚板块(在NNR-NUVEL1A地质模型下)的运动速率,由此得到了该区的现今地壳形变速率图。结果表明GPS站主要运动方向为北北西,基本上与天山褶皱带走向正交,形成对天山的正向挤压。同时对乌恰—伽师(20021225MS5.8)及伽师—巴楚(20030224MS6.8)地震前后的地壳运动进行了应变计算及分析,得出大震前震中及邻近地区会大面积产生高剪应变集中区的结论。
We have made 6 terms of GPS surveies in the Wuqia and Jiashi areas in Xinjiang since 1998. Combined with the data from neighbor IGS stations, we calculated and analyzed the deformation velocity of more than 50 GPS stations under ITRA200 and the relative ones to the Eurasia Plate (under NNR-NUVEL1A model), obtained present crustal deformation velocity map. The result shows that the principal motion is in NNW and generally orthogonal with the Tianshan fold belt, forming the squeeze to the Tianshan Mts. In addition, the changes of the stress field before and after the Wuqia-Jiashi M \-S 5.8 earthquake on Dec. 25, 2002 and the Jiashi-Bachu M \-S 6.8 earthquake on Feb. 24, 2003 show that it is possible to break out strong shock at the field of high shear strain accumulation.
We have made 6 terms of GPS surveies in the Wuqia and Jiashi areas in Xinjiang since 1998. Combined with the data from neighbor IGS stations, we calculated and analyzed the deformation velocity of more than 50 GPS stations under ITRA200 and the relative ones to the Eurasia Plate (under NNR-NUVEL1A model), obtained present crustal deformation velocity map. The result shows that the principal motion is in NNW and generally orthogonal with the Tianshan fold belt, forming the squeeze to the Tianshan Mts. In addition, the changes of the stress field before and after the Wuqia-Jiashi M \-S 5.8 earthquake on Dec. 25, 2002 and the Jiashi-Bachu M \-S 6.8 earthquake on Feb. 24, 2003 show that it is possible to break out strong shock at the field of high shear strain accumulation.
引文
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[2]王晓强,王琪,程瑞忠,等.伽师及邻近地区GPS地壳形变监测及初步分析[J].内陆地震,2000,14(3):200—206.
[3]乔学军,王晓强,王琪,等.新疆伽师地区现今构造运动和地形变GPS监测的初步研究[J].地壳形变与地震,2000,20(3):49—56.
[4]陆彩萍,王解先.GPS监测地壳运动数据处理[J].大地测量与地球动力学,2002,22(4):56—60.
[5]胡明城,鲁福.现代大地测量学[M].北京:测绘出版社,1994.
[6]郭良迁.对中国大陆地壳水平变形的初步探索[J].中国地震,2000,16(2):126—134.
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