汶川地震前后山西断陷带的地壳运动
|
摘要
依据GPS结果,采用"块体加载"有限元方法对汶川地震前后山西断陷带的地壳运动进行数值模拟。结果显示:震前该区呈相对均一的NW向拉张,震后以构造挤压为主,南端为强烈拉张,主压应力最高值为前期5～6倍,主张应力最高值为前期的2倍,主压应力方向自北而南由NW向转为NEE向。这些与跨断层短水准、长剖面水准、GPS长基线时序曲线等解算结果一致,表明汶川地震后鄂尔多斯与华北平原块体之间相对挤压、扭错增强,并导致山西断陷带地壳形变与构造应力场变化明显。
Based on the newly obtained GPS data and the "block loading" FEA method,the crustal movement of Shanxi rift zone within two time span(1999—2007,2007—2009),which before and after the Wenchuan earthquake are simulated,respectively.The results show that the stress and strain fields assume opproximately unifrom NW-SE extension before the earthquake.However,after the earthquake they are featured with remarkable compression accompanied with notable extension in the south region.Compared with 1999—2007,in 2007—2009 the maximum principal compressive and tensile stress increases 5-6 times and about 2 times,respectively,and from the north region to the south region of Shanxi rift zone,the direcion of the principal compressive stress changes from NW to NEE.Such stress and strain variation is verified by time-series of across-fault short level survey,long distance level survey and baseline of GPS continuous site.It indicates that the compressive and strike-slip displacement between Erdos block and North China Plain block increased after the Wenchuan earthquake.As a result,the crustal deformation and tectonic stress field of the Shanxi rift zone,which located in the boundary of the two blocks,change distinctly.
Based on the newly obtained GPS data and the "block loading" FEA method,the crustal movement of Shanxi rift zone within two time span(1999—2007,2007—2009),which before and after the Wenchuan earthquake are simulated,respectively.The results show that the stress and strain fields assume opproximately unifrom NW-SE extension before the earthquake.However,after the earthquake they are featured with remarkable compression accompanied with notable extension in the south region.Compared with 1999—2007,in 2007—2009 the maximum principal compressive and tensile stress increases 5-6 times and about 2 times,respectively,and from the north region to the south region of Shanxi rift zone,the direcion of the principal compressive stress changes from NW to NEE.Such stress and strain variation is verified by time-series of across-fault short level survey,long distance level survey and baseline of GPS continuous site.It indicates that the compressive and strike-slip displacement between Erdos block and North China Plain block increased after the Wenchuan earthquake.As a result,the crustal deformation and tectonic stress field of the Shanxi rift zone,which located in the boundary of the two blocks,change distinctly.
引文
1地震数据来源于地震信息网www.celc.ac.ch
2李延兴,等.弹性板块运动模型研究进展[J].地球物理学进展,2007,22(4):1201-1208.(Li Yanxing,et al.Theresearch progress in elastic plate motion model[J].Progressin Geophysics,2007,22(4):1 201-1 208)
3李延兴,等.菲律宾海板块的整体旋转线性应变模型与板内形变-应变场[J].地球物理学报,2006,49(5):1339-1 346.(Li Yanxing,et al.Integral-rotation linear strain mod-el and intraplate deformation-strain field of the PhilippineSea Plate[J].Chinese Journal of Geophysics,2006,49(5):1 339-1 346)
4李延兴,等.汶川Ms8.0地震孕育发生的机制与动力学问题[J].地球物理学报,2009,52(2):519-530.(LiYanxing,et al.The mechanism and dynamics of the genera-tion and occurrence for Wenchuan Ms8.0 earthquake[J].Chinese Journal of Geophysics,2009,52(2):519-530)
5刘峡,等.用GPS资料研究华北地区形变场和构造应力场[J].大地测量与地球动力学,2006,(3):33-39.(LiuXia,et al.Deformation field and tectonic stress field con-strained by GPS observations in North China[J].Journal ofGeodesy and Geodynamics,2006,(3):33-39)
6郑勇,傅容珊,熊熊.中国大陆及周边地区现代岩石圈演化动力学模拟[J].地球物理学报,2006,49(2):415-427.(Zheng Yong,Fu Rongshan and Xiong Xiong.Dynamicsimulation of lithospheric evolution from the modern Chinamainland and its surrounding areas[J].Chinese Journal ofGeophysics,2006,49(2):415-427)
7谢富仁,等.中国大陆及邻区现代构造应力场分区[J.地球物理学报,2004,47(4):654-662.(Xie Furen,et al.Reginal division of the tectonic stress field in China and ad-jacent areas[J].Chinese Journal of Geophysics,2004,47(4):654-662)
8韩月萍,杨国华,陈聚忠.华北地区水准剖面结果与地震危险性分析[R].2011年年度地震趋势研究专题报告.(Han Yueping,Yang Guohua and Chen Juzhong.Levelingsurvey in North China and its seismic risk[R].Special re-port on the earthquake tendency in 2011)
9杜雪松,郭良迁,孙东颖.华北地区跨断层资料形变异常统计分析[R].2011年度地震趋势研究专题报告.(DuXuesong,Guo Liangqian and Sun Dongying.Statistics of ab-normal deforming from across-fault survey in North China[R].Special report on the earthquake tendency in 2011)
10郭良迁,等.GPS连续站的基线变化与青藏块体的现代活动[J].大地测量与地球动力学,2009,(4):10-14.(Guo Liangqian,et al.Baseline variation of GPS continuoussites and current activity of Qinghai-Tibet block[J].Journalof Geodesy and Geodynamics,2009,(4):10-14)
11张风霜,孙东颖.GPS连续观测站基线分析[R].2011年度地震趋势研究专题报告.(Zhang Fengshuang and SunDongying.Analysis of baseline of GPS Continuous station[R].Special report on the earthquake tendency in 2011)
2李延兴,等.弹性板块运动模型研究进展[J].地球物理学进展,2007,22(4):1201-1208.(Li Yanxing,et al.Theresearch progress in elastic plate motion model[J].Progressin Geophysics,2007,22(4):1 201-1 208)
3李延兴,等.菲律宾海板块的整体旋转线性应变模型与板内形变-应变场[J].地球物理学报,2006,49(5):1339-1 346.(Li Yanxing,et al.Integral-rotation linear strain mod-el and intraplate deformation-strain field of the PhilippineSea Plate[J].Chinese Journal of Geophysics,2006,49(5):1 339-1 346)
4李延兴,等.汶川Ms8.0地震孕育发生的机制与动力学问题[J].地球物理学报,2009,52(2):519-530.(LiYanxing,et al.The mechanism and dynamics of the genera-tion and occurrence for Wenchuan Ms8.0 earthquake[J].Chinese Journal of Geophysics,2009,52(2):519-530)
5刘峡,等.用GPS资料研究华北地区形变场和构造应力场[J].大地测量与地球动力学,2006,(3):33-39.(LiuXia,et al.Deformation field and tectonic stress field con-strained by GPS observations in North China[J].Journal ofGeodesy and Geodynamics,2006,(3):33-39)
6郑勇,傅容珊,熊熊.中国大陆及周边地区现代岩石圈演化动力学模拟[J].地球物理学报,2006,49(2):415-427.(Zheng Yong,Fu Rongshan and Xiong Xiong.Dynamicsimulation of lithospheric evolution from the modern Chinamainland and its surrounding areas[J].Chinese Journal ofGeophysics,2006,49(2):415-427)
7谢富仁,等.中国大陆及邻区现代构造应力场分区[J.地球物理学报,2004,47(4):654-662.(Xie Furen,et al.Reginal division of the tectonic stress field in China and ad-jacent areas[J].Chinese Journal of Geophysics,2004,47(4):654-662)
8韩月萍,杨国华,陈聚忠.华北地区水准剖面结果与地震危险性分析[R].2011年年度地震趋势研究专题报告.(Han Yueping,Yang Guohua and Chen Juzhong.Levelingsurvey in North China and its seismic risk[R].Special re-port on the earthquake tendency in 2011)
9杜雪松,郭良迁,孙东颖.华北地区跨断层资料形变异常统计分析[R].2011年度地震趋势研究专题报告.(DuXuesong,Guo Liangqian and Sun Dongying.Statistics of ab-normal deforming from across-fault survey in North China[R].Special report on the earthquake tendency in 2011)
10郭良迁,等.GPS连续站的基线变化与青藏块体的现代活动[J].大地测量与地球动力学,2009,(4):10-14.(Guo Liangqian,et al.Baseline variation of GPS continuoussites and current activity of Qinghai-Tibet block[J].Journalof Geodesy and Geodynamics,2009,(4):10-14)
11张风霜,孙东颖.GPS连续观测站基线分析[R].2011年度地震趋势研究专题报告.(Zhang Fengshuang and SunDongying.Analysis of baseline of GPS Continuous station[R].Special report on the earthquake tendency in 2011)
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心