用二维有限元研究青藏块体东北缘地壳的水平运动
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摘要
将1999～2001年、2001～2004年两个时段中青藏块体东北缘GPS水平速度场进行参考框架的变换,扣除区域刚性整体平移和旋转,得到反映区域内部相对运动的水平速度场。利用这个速度场,通过构建该区二维有限元模型,结合最优化原理,反演区域分段边界位移。将反演结果作为边界约束并将变换参考框架后的水平速度场作为有限元节点载荷,模拟区域内部水平运动场并计算其主应变率场、最大剪应变率场,以分析这两个时段中这两种场的变化特征及其与地震孕育之间的关系。
By transforming the reference frame of the velocity field of horizontal movement observed by GPS during 1999-2001 and 2001-2004 in the northeastern margin of Qinghai-Tibet block and then deducting the holistic movement of the region from it,the result out velocity field reflecting relative movement in the region is gotten.On the basis of this velocity field and the optimization theory,the segmented displacement of the boundary of the studied area are deduced with two-dimensional finite element model of linear elasticity.Taking the results as boundary constraint and the velocity field of horizontal movement after transforming reference frame as the load of FEM node,the velocity field of horizontal movement in the region is simulated,the principal strain rate field and maximal shear strain rate field are calculated,the variety characteristics of the two rate fields and relation between the variety characteristics and strong earthquake preparation are analyzed.
By transforming the reference frame of the velocity field of horizontal movement observed by GPS during 1999-2001 and 2001-2004 in the northeastern margin of Qinghai-Tibet block and then deducting the holistic movement of the region from it,the result out velocity field reflecting relative movement in the region is gotten.On the basis of this velocity field and the optimization theory,the segmented displacement of the boundary of the studied area are deduced with two-dimensional finite element model of linear elasticity.Taking the results as boundary constraint and the velocity field of horizontal movement after transforming reference frame as the load of FEM node,the velocity field of horizontal movement in the region is simulated,the principal strain rate field and maximal shear strain rate field are calculated,the variety characteristics of the two rate fields and relation between the variety characteristics and strong earthquake preparation are analyzed.
引文
1陈炳蔚,王彦斌,左国朝.青藏高原北部地块划分及构造演化[J].地球物理学报,1995,38(增刊):98～113.1Chen Bingwei,Wang Yanbin and Zuo Guochao.Terrain sub-division of the northern Qinghai-Tibet plateau and its tectonic evolution[J].Chinese Journal of Geophysics,1995,38(Supp.):98-113.(in Chinese)
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3张希,等.北祁连-汉西地区强震地点预测[J].大地测量与地球动力学,2005,25(1):40～46.3Zhang Xi,et al.Prediction of place strong earthquake in Northern Qilian-Hexi area[J].Journal of Geodesy and Geo-dynamics,2005,25(1):40-46.(in Chinese)
4张永志,王卫东.青藏高原东北缘断层活动变形的模拟研究[J].大地测量与地球动力学,2004,24(1):63～67.4Zhang Yongzhi and Wang Weidong.Deformation of multi-fault movements in northeastern margin of Tibetan plateau[J].Journal of Geodesy and Geodynamics,2004,24(1):63-67.(in Chinese)
5崔笃信,等.青藏块体东北缘地壳水平运动状态[J].大地测量与地球动力学,2004,24(3):29～34.5Cui Duxin,et al.Crustal horizontal movement state of north-eastern of Qinghai-Tibet block[J].Journal of Geodesy and Geodynamics,2004,24(3):29-34.(in Chinese)
6王双绪,等.兰天武地区现今大地垂直形变场演化与地壳运动特征[J].地壳形变与地震,1995,15(1):62～70.6Wang Shuangxu,et al.Characteristics of the evolution of re-cent vertical deformation field and the crustal movement in Lanzhou-Tianshui-Wudu area[J].Crustal Deformation and Earthquake,1995,15(1):62-70.(in Chinese)
7王双绪,等.昆仑8.1级地震前青藏块体东北缘构造运动特征[J].大地测量与地球动力学,2004,24(1):50～55.7Wang Shuangxu,et al.features of horizontal movement in northeastern margin of Qinghai-Tibet block beforeMs8.1Kunlun earthquake[J].Journal of Geodesy and Geodynam-ics,2004,24(1):50-55.(in Chinese)
8黄立人,马青.祁连-河西地区的现今水平变形[J].大地测量与地球动力学,2003,23(4):9～13.8Huang Liren and Ma Qing.Recent horizontal deformation in qilianshan-Hexi corridor area[J].Journal of Geodesy and Geodynamics,2003,23(4):9-13.(in Chinese)
9王庆良,等.青藏块体东北缘现今地壳运动[J].大地测量与地球动力学,2002,22(4):12～16.9Wang Qingliang,et al.Present-day crustal movement of northeastern margin of Qinghai-Tibet block[J].Journal of geodesy and Geodynamics,2002,22(4):12-16.(in Chi-nese)
10江在森,等.青藏块体东北缘近期水平运动与变形[J].地球物理学报,2001,44(9):636～644.10Jiang Zaisen,et al.Recent horizontal movement and deform-ation in the northeast margin of Qinghai-Tibet block[J].Chinese Journal of Geophysics,2001,44(9):636-641.(in Chinese)
11张希,等.1999～2001年青藏块体东北缘地壳水平运动的非震负位错模型及变形分析[J].地震学报,2003,25(4):374～381.11Zhang Xi,et al.A seismic negative dislocation model and deformation analysis of1999to2001crustal horizontal movement in the northeast margin of qinghai-Tibet block[J].Acta Seismologica Sinica,2003,25(4):374-381.(in Chinese)
12张晓亮,等.青藏块体东北缘地壳运动与孕震特征[J].大地测量与地球动力学,2004,24(4):76～81.12Zhang Xiaoliang,et al.Recent horizontal movement and seismogenic features of northeastern margin of Qinghai-Ti-bet block[J].Journal of Geodesy and Geodynamics,2004,24(4):76-81.(in Chinese)
13甘卫军,等.青藏高原地壳水平差异运动的GPS观测研究[J].大地测量与地球动力学,2004,24(1):29～35.13Gan Weijun,et al.Horizontal crustal movement of Tibetan plateau from GPS measurements[J].Journal of Geodesy and Geodynamics,2004,24(1):29-35.(in Chinese)
14虢顺民,等.青藏高原东北缘晚第四纪块体划分与运动态势研究[J].地震地质,2000,22(3):219～231.14Guo Shunmin,et al.Division and motion status of blocks for the northeastern Tibetan Plateau in late quaternary[J].Seismology and Geology,2000,22(3):219-231.(in Chi-nese)
15崔笃信,等.甘青块体东西部运动分界带的确定[J].大地测量与地球动力学,2007,27(1):24～30.15Cui duxin,et al.Determination of movement boaundary belt of Gansu-Qinghai block[J].Journal of Geodesy and Geody-namics,2007,27(1):24-30.(in Chinese)
16徐纪人,赵志新.青藏高原及周围地区区域应力场与构造运动特征[J].地震地质,2006,33(2):275～285.16Xu Jiren and Zhao Zhixin.Characteristics of the regional stress field and tectonic movement on the Qinghai-Tibet da-teau and in its surrounding areas[J].Seismology and Geol-ogy,2006,33(2):275-285.(in Chinese)
17独知行,卢秀山.基于力学模式的大地测量反演理论及应用[M].北京:地震出版社,2003.17Du Zhixing and Lu Xiushan.Theory and applicartion of ge-odesy inversion based on mechanical models[M].Beijing:Seismological Press,2002.(in Chinese)
2王双绪,丁平.中国西部形变监测与地震预测研究进展[J].大地测量与地球动力学,2006,26(增):1～4.2Wang Shuangxu and Ding Ping.Progress of study on crustal deformation and earthquake prediction in Western China[J].Journal of Geodesy and Geodynamics,2006,26(Supp.):1-4.(in Chinese)
3张希,等.北祁连-汉西地区强震地点预测[J].大地测量与地球动力学,2005,25(1):40～46.3Zhang Xi,et al.Prediction of place strong earthquake in Northern Qilian-Hexi area[J].Journal of Geodesy and Geo-dynamics,2005,25(1):40-46.(in Chinese)
4张永志,王卫东.青藏高原东北缘断层活动变形的模拟研究[J].大地测量与地球动力学,2004,24(1):63～67.4Zhang Yongzhi and Wang Weidong.Deformation of multi-fault movements in northeastern margin of Tibetan plateau[J].Journal of Geodesy and Geodynamics,2004,24(1):63-67.(in Chinese)
5崔笃信,等.青藏块体东北缘地壳水平运动状态[J].大地测量与地球动力学,2004,24(3):29～34.5Cui Duxin,et al.Crustal horizontal movement state of north-eastern of Qinghai-Tibet block[J].Journal of Geodesy and Geodynamics,2004,24(3):29-34.(in Chinese)
6王双绪,等.兰天武地区现今大地垂直形变场演化与地壳运动特征[J].地壳形变与地震,1995,15(1):62～70.6Wang Shuangxu,et al.Characteristics of the evolution of re-cent vertical deformation field and the crustal movement in Lanzhou-Tianshui-Wudu area[J].Crustal Deformation and Earthquake,1995,15(1):62-70.(in Chinese)
7王双绪,等.昆仑8.1级地震前青藏块体东北缘构造运动特征[J].大地测量与地球动力学,2004,24(1):50～55.7Wang Shuangxu,et al.features of horizontal movement in northeastern margin of Qinghai-Tibet block beforeMs8.1Kunlun earthquake[J].Journal of Geodesy and Geodynam-ics,2004,24(1):50-55.(in Chinese)
8黄立人,马青.祁连-河西地区的现今水平变形[J].大地测量与地球动力学,2003,23(4):9～13.8Huang Liren and Ma Qing.Recent horizontal deformation in qilianshan-Hexi corridor area[J].Journal of Geodesy and Geodynamics,2003,23(4):9-13.(in Chinese)
9王庆良,等.青藏块体东北缘现今地壳运动[J].大地测量与地球动力学,2002,22(4):12～16.9Wang Qingliang,et al.Present-day crustal movement of northeastern margin of Qinghai-Tibet block[J].Journal of geodesy and Geodynamics,2002,22(4):12-16.(in Chi-nese)
10江在森,等.青藏块体东北缘近期水平运动与变形[J].地球物理学报,2001,44(9):636～644.10Jiang Zaisen,et al.Recent horizontal movement and deform-ation in the northeast margin of Qinghai-Tibet block[J].Chinese Journal of Geophysics,2001,44(9):636-641.(in Chinese)
11张希,等.1999～2001年青藏块体东北缘地壳水平运动的非震负位错模型及变形分析[J].地震学报,2003,25(4):374～381.11Zhang Xi,et al.A seismic negative dislocation model and deformation analysis of1999to2001crustal horizontal movement in the northeast margin of qinghai-Tibet block[J].Acta Seismologica Sinica,2003,25(4):374-381.(in Chinese)
12张晓亮,等.青藏块体东北缘地壳运动与孕震特征[J].大地测量与地球动力学,2004,24(4):76～81.12Zhang Xiaoliang,et al.Recent horizontal movement and seismogenic features of northeastern margin of Qinghai-Ti-bet block[J].Journal of Geodesy and Geodynamics,2004,24(4):76-81.(in Chinese)
13甘卫军,等.青藏高原地壳水平差异运动的GPS观测研究[J].大地测量与地球动力学,2004,24(1):29～35.13Gan Weijun,et al.Horizontal crustal movement of Tibetan plateau from GPS measurements[J].Journal of Geodesy and Geodynamics,2004,24(1):29-35.(in Chinese)
14虢顺民,等.青藏高原东北缘晚第四纪块体划分与运动态势研究[J].地震地质,2000,22(3):219～231.14Guo Shunmin,et al.Division and motion status of blocks for the northeastern Tibetan Plateau in late quaternary[J].Seismology and Geology,2000,22(3):219-231.(in Chi-nese)
15崔笃信,等.甘青块体东西部运动分界带的确定[J].大地测量与地球动力学,2007,27(1):24～30.15Cui duxin,et al.Determination of movement boaundary belt of Gansu-Qinghai block[J].Journal of Geodesy and Geody-namics,2007,27(1):24-30.(in Chinese)
16徐纪人,赵志新.青藏高原及周围地区区域应力场与构造运动特征[J].地震地质,2006,33(2):275～285.16Xu Jiren and Zhao Zhixin.Characteristics of the regional stress field and tectonic movement on the Qinghai-Tibet da-teau and in its surrounding areas[J].Seismology and Geol-ogy,2006,33(2):275-285.(in Chinese)
17独知行,卢秀山.基于力学模式的大地测量反演理论及应用[M].北京:地震出版社,2003.17Du Zhixing and Lu Xiushan.Theory and applicartion of ge-odesy inversion based on mechanical models[M].Beijing:Seismological Press,2002.(in Chinese)
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