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在中国大陆活动地块假说及活动边界研究的基础上，将中国大陆按照地震活动特征进行分区. 利用大地震的震源机制资料和历史强震资料，结合小震综合节面解，研究了各地震区的应力应变状态，给出了各地震区的平均应力主轴方向和平均应变率. 应用地震应变能积累释放模型研究了各地震区的地震活动水平. 结果表明最大剪切应变率与地震活动水平存在线性关系. 将地震资料给出的中国大陆地壳应力应变场与GPS测量给出的结果进行了比较，初步说明了两种结果存在着统一性，从而显示出活动地块运动变形与强震活动的内在联系. 相似文献
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基于GPS多期复测资料, 利用最小二乘配置方法计算川滇地区应变参数, 分析该区域应变率场分布及其变化特征并探讨其分布与强震关系。 研究结果表明: ① 各时段应变率场空间分布的明显变化应属于大于GPS资料误差的真实地壳构造形变信息; ② 最大剪应变率及第一、 第二剪应变率的结果反映了走滑断裂对区域变形的显著控制; ③ 主应变率, 东西、 南北向应变率场动态结果反映的汶川地震孕震的空间尺度较大; ④ 在本区大致反映北东向与北西向剪切变形的第一剪应变率、 东西向应变率、 南北向应变率及最大剪应变率与6级以上地震对应较好。 相似文献
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根据中国大陆不同来源的多个GPS区域监测网1991～1999年间的观测资料和“中国地壳运动观测网络”基本网1998～2000年的观测资料，联合处理得到中国大陆地壳水平运动速度场结果，通过最小二乘配置法建立中国大陆水平运动速度场模型，获得了基于连续介质假设的中国大陆水平应变场（或称为视应变场）初步结果. 分析了水平运动、应变场空间分布特征及其与强震的关系，并简要分析了2001年11月14日昆仑山口西8.1级大地震的区域构造变形背景. 结果表明：中国大陆中西部构造变形强烈，应变速率值高，又以青藏块体及其边缘和新疆西部最为显著. 除川滇、新疆西部外，大部分地区的近东西向断裂存在左旋剪切变形，近南北向的断裂存在右旋剪切变形. 而东部地区构造变形相对较弱. 强震通常发生在剪切应变率的高值区及其边缘，尤其是与构造变形背景相一致的剪应变率高值区. 昆仑山口西8.1级地震发生在最显著的东西向左旋剪切应变率高值区，从该区域的应变状态分析，具备近东西向断裂产生巨型走滑破裂错动的构造变形背景. 相似文献
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利用中国大陆地区的GPS速度观测资料,通过2次插值计算,得到地应变率场。首先将GPS观测结果通过插值计算获得中国大陆及邻区均匀网格节点上的速度值,然后运用有限单元中形函数(Lagrange插值函数)的求导方法,计算每个网格单元积分点处的地应变率分量,从而获得中国大陆及邻区稳定的地应变率场的分布。计算结果表明,总体上中国大陆及邻区地应变率分布西高东低;以南北地震带为界,西部地区应变率高,而东部地区,尤其是华南地区地应变率很低;而塔里木盆地、鄂尔多斯盆地等构造稳定区域的地应变率也很小。此外,还发现中国大陆及邻区地应变率分布与地震活动之间的关系非常密切,变形产生的应变能密度与地震密度(1.0°×1.0°内发生的地震数目)之间吻合得很好,应变能密度高的区域,地震活动性较强;反之,则较弱。同时,最大剪应变率、面应变率与地震活动性之间也呈对应关系。 相似文献
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利用中国地壳运动观测网络GPS区域网1999、2001、2004、2007年观测资料及中国大陆构造环境监测网络区域网2009、2011年观测资料,解算了南北地震带相对华南地块的GPS速度场,并用最小二乘配置方法解算了南北地震带南、北部地区应变率场的多期次结果,通过分析汶川地震前、后地壳运动速度场和应变率场的动态变化,进一步研究了汶川地震前区域地壳形变和应变积累背景与孕震异常的形变场主要特征及其形成机制. 相似文献
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中国大陆地壳水平运动速度场与应变场 总被引：1，自引：0，他引：1
收集了中国大陆及周边地区GPS网的有关数据，提出了GPS网速度场的不同融合方法；经过融合建立了中国大陆及周边地区统一的地壳运动速度场，该速度场使用的有效GPS站共423个，其覆盖面积为1200万km^2；初步总结出中国大陆及周边地区地壳水平运动空间分布的基本特征；建立了板内块体的刚性弹塑性运动应变模型，对其进行了块体应变参数唯一性与速度残差中误差最小检验；根据中国大陆及周边地区的速度场，估计了8个块体的应变参数，分析了这些块体的应变状态，估计出的各个块体的应变状态与地质学、地球物理学方法估计的结果具有很好的一致性。用喜马拉雅块体主压应变方向估计的印度板块向欧亚板块碰撞力的主方向为北东7．1度。 相似文献
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基于GPS的华北地区地壳水平形变特征研究 总被引：1，自引：0，他引：1
利用中国大陆构造环境监测网络2009、2011年2期的GPS数据资料,计算得到华北地区相对于稳定的欧亚板块的区域水平速度场。根据水平速度场,基于连续变形假说,采用三角形方法计算了区域应变场特征值,并用GMT绘制了其分布图像。结合地震地质资料对该区的地壳水平形变特征进行分析研究,得出了有意义的结论:(1)水平相对运动与应变率场分布显示,板块交界处的断裂带及其附近区域地壳运动差异显著,应变率量值较为突出;(2)山西断陷带的活动方式与地质结果具有差异性;(3)区内最大剪应变、面膨胀的高值区主要位于环渤海的京津唐地区、山西断陷带中南部及郯庐断裂带中南段。 相似文献
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Min Wang Zhengkang Shen Zhijun Niu Zusheng Zhang Hanrong Sun Weijun Gan Qi Wang Qun Ren 《中国科学D辑(英文版)》2003,46(2):25-40
We obtain the preliminary result of crustal deformation velocity field for the Chinese continent by analyzing GPS data from the Crustal Motion Observation Network of China (CMONOC), particularly the data from the regional networks of CMONOC observed in 1999 and 2001. We delineate 9 technically active blocks and 2 broadly distributed deformation zones out of a dense GPS velocity field, and derive block motion Euler poles for the blocks and their relative motion rates. Our result reveals that there are 3 categories of deformation patterns in the Chinese continent. The first category, associated with the interior of the Tibetan Plateau and the Tianshan orogenic belt, shows broadly distributed deformation within the regions. The third category, associated with the Tarim Basin and the region east of the north-south seismic belt of China, shows block-like motion, with deformation accommodated along the block boundaries only. The second category, mainly associated with the borderland of the Tibetan Plateau, such as the Qaidam, Qilian, Xining (in eastern Qinghai), and the Diamond-shaped (in western Sichuan and Yunnan) blocks, has the deformation pattern between the first and the third, i.e. these regions appear to deform block-like, but with smaller sizes and less strength for the blocks. Based on the analysis of the lithospheric structures and the deformation patterns of the regions above, we come to the inference that the deformation modes of the Chinese continental crust are mainly controlled by the crustal structure. The crust of the eastern China and the Tarim Basin is mechanically strong, and its deformation takes the form of relative motion between rigid blocks. On the other hand, the northward indentation of the Indian plate into the Asia continent has created the uplift of the Tibetan Plateau and the Tianshan Mountains, thickened their crust, and raised the temperature in the crust. The lower crust thus has become ductile, evidenced in low seismic velocity and high electric conductivity observed. The brittle part of the crust, driven by the visco-plastic flow of the lower crust, deforms extensively at all scales. The regions of the second category located at the borderland of the Tibetan Plateau are at the transition zone between the regions of the first and the third categories in terms of the crustal structure. Driven by the lateral boundary forces, their deformation style is also between the two, in the form of block motion and deformation with smaller blocks and less internal strength. 相似文献
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The Contemporary Tectonic Strain Rate Field of Continental China Predicted from GPS Measurements and its Geodynamic Implications 总被引：7，自引：0，他引：7
In Appling studies, the strain rate in China has been computed from using different methods, resulting in quite different
estimates of the strain rate the geo-statistics from GPS velocity field of Chinese continent, we obtain the velocity value
at each little regularly spaced grid point, by kriging interpolation and the component of strain rate for each volume element,
using a method similar to the derivation of shape functions in the finite element algorithm. Therefore the distribution of
the strain rate field in whole for the Chinese continent is presented. The result shows that the orientations of principal
strain rates are consistent with those of the P and T axes of focal mechanisms. The distribution of maximum shear strain rate
clearly delineates some major active fault zones surrounding the Tibetan Plateau. The maximum shear strain rate is comparable
with that obtained from analysis of seismic moment release. In part of the Tibetan Plateau containing normal faults and pull-apart
grabens, we obtain an extensional state of strain. The absolute value of the strain rate in West China is approximately 5
times larger than that of East China, and the pattern of the strain rate field in most of the Chinese continent is controlled
by the India/Eurasia collision. 相似文献
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We obtain the preliminary result of crustal deformation velocity field for the Chinese con-tinent by analyzing GPS data from the Crustal Motion Observation Network of China (CMONOC), particularly the data from the regional networks of CMONOC observed in 1999 and 2001. We de-lineate 9 tectonically active blocks and 2 broadly distributed deformation zones out of a denseGPS velocity field, and derive block motion Euler poles for the blocks and their relative motionrates. Our result reveals that there are 3 categories of deformation patterns in the Chinese conti-nent. The first category, associated with the interior of the Tibetan Plateau and the Tianshan oro-genic belt, shows broadly distributed deformation within the regions. The third category, associatedwith the Tarim Basin and the region east of the north-south seismic belt of China, shows block-likemotion, with deformation accommodated along the block boundaries only. The second category, mainly associated with the borderland of the Tibetan Plateau, such as the Qaidam, Qilian, Xining(in eastern Qinghai), and the Diamond-shaped (in western Sichuan and Yunnan) blocks, has thedeformation pattern between the first and the third, i.e. these regions appear to deform block-like,but with smaller sizes and less strength for the blocks. Based on the analysis of the lithosphericstructures and the deformation patterns of the regions above, we come to the inference that thedeformation modes of the Chinese continental crust are mainly controlled by the crustal structure.The crust of the eastern China and the Tarim Basin is mechanically strong, and its deformationtakes the form of relative motion between rigid blocks. On the other hand, the northward indentation of the Indian plate into the Asia continent has created the uplift of the Tibetan Plateau and the Tianshan Mountains, thickened their crust, and raised the temperature in the crust. The lower crust thus has become ductile, evidenced in low seismic velocity and high electric conductivity observed. The brittle part of the crust, driven by the visco-plastic flow of the lower crust, deforms extensively at all scales. The regions of the second category located at the borderland of the Tibetan Plateau are at the transition zone between the regions of the first and the third categories in terms of the crustal structure. Driven by the lateral boundary forces, their deformation style is also between the two, in the form of block motion and deformation with smaller blocks and less internal strength. 相似文献
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为了清晰认识发生于青藏高原西北部2008年与2014年的两次于田MS7.3地震发震构造环境与构造地貌特征,本文利用DEM(数字高程模型)数据分析"喀喇昆仑—西昆仑—康西瓦地区"的地形地貌特征,结合区域活动断裂研究资料、相对于塔里木盆地的两期GPS速度场资料和区域运动学特征等讨论两次MS7.3地震所处的青藏高原西北部区域构造环境和地壳运动学特征,分析喀喇昆仑断裂、阿尔金断裂康西瓦段、龙木错-邦达错断裂及贡嘎错断裂所围限的西昆仑地块的地质构造背景、阿尔金断裂西南端发震断裂活动性及孕震环境等发震构造基本条件;进而利用"地形剖面"方法及断裂分布特征分析震源区的地形地貌特征,给出晚第四纪以来的地貌形态与发震构造的关系,从区域构造地貌学和GPS地壳运动学的角度探讨中上地壳变形特征及孕震过程;最后讨论区域孕震构造、克尔牙张性裂谷演化过程和地球动力学背景等。通过地形剖面及区域地貌综合分析新疆于田2008年MS7.3拉张型发震构造和2014年MS7.3走滑拉张型地震的发震构造特点的区别,认为2014年发生的地震可能与2008年MS7.3地震同震库伦应力变化、触发过程及震后变形过程密切相关,并且青藏高原西北部地区存在明显的东西向拉张性构造单元,可能与青藏高原10~15 Ma以来的地壳减薄过程有关。 相似文献
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以GPS观测资料和地震学研究成果为约束，针对不同流变参数的中国大陆岩石圈模型，数值模拟了岩石粘度与中国大陆板块边界作用强度的关系，探讨了陆-陆碰撞对中国大陆分层岩石圈运动的驱动机制．给出了陆-陆碰撞驱动力、附加地形与山根浮力及热浮力对中国大陆构造运动的驱动特点．印度板块、太平洋板块和菲律宾板块对中国大陆驱动的边界作用强度之比约是4：1．25：1，所引起的水平主压应力主要集中在坚硬岩石层；而附加地形等垂直方向作用力在水平方向产生的最大主压应力则主要集中在软弱岩石层．这种垂直方向上的作用力在高原南部地区阻碍陆-陆碰撞向北的推挤运动，在高原东北部增加对其它块体的推挤作用。 相似文献
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Present-day horizontal deformation status of continental China and its driving mechanism 总被引：2，自引：0，他引：2
CHEN XiaoBin Institute of Geology China Earthquake Administration Beijing China 《中国科学D辑(英文版)》2007,50(11):1663-1673
Based on velocity data of 933 GPS sites and using the methods of Ordinary Kriging interpolation and shape function derivation, this study has obtained the strain rate field of continental China in the spherical coordinates. In comparison with previous research results, it is found that such a strain rate field can be described by both the continuous deformation and block motions in the continent. The Tibetan Plateau and Tianshan region are characterized by continuous deformation which is distributed across the whole area. Within the blocks of South China, Tarim, Ordos, and Northeast China, little crustal deformation and deformation occurs primarily on the faults along their boundaries, which can be explained by the model of block motion. In other regions, such as the Yinshan-Yanshan block, North China block, and East Shandong-Yellow Sea, deformation patterns can be explained by both models. Besides, from southwest to northeast of continental China, there are three remarkable extensional zones of NW trending. These results imply that the NNE directed push of the India plate is the primary driving force accounting for the internal deformation of continental China. It produces the uplift, hori-zontal shortening and vertical thickening of the Tibetan Plateau as well as radiation-like material extru-sion. Of these extruded materials, one part accommodates the eastward "escape" of other blocks, generating convergence and compression of western China and widespread extension and local com-plicated deformation in eastern China under the joint action of the surrounding settings. The other part opens a corridor between the South China block and Tibetan Plateau, flowing toward southeast to the Myanmar range arc and filling the gap there which is produced by back-arc extension due to plate subduction. 相似文献
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基于地壳黏弹模型在GPS观测资料和地震位错数据为约束条件下,应用有限元数值模拟方法对2001年昆仑山8.1级、2008年汶川8.0级和2015年尼泊尔8.1级特大地震引起的地壳形变分布特征进行了模拟计算,获得了地震位移场和形变场.这3次大地震分别发生在青藏高原的北部、东部边界和南部边界,尽管震级大小基本相当,但发震区域和发震断层性质都各不相同,其各自产生的地壳形变场分布特征存在明显的差异,主要表现为形变场区域大小、幅值大小等的差异,以及在不同地壳深度也存在明显的差异,这些差异主要取决于地震断层性质和地下介质结构的不同.通过模拟计算,可以进一步了解大地震产生的应力加卸载区分布特征,对预测未来地震发生区域范围提供重要参考依据. 相似文献
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针对2015年4月25日尼泊尔Mw7.8地震的孕震特征,本文首先对覆盖尼泊尔及周边地区的5套GPS水平速度场结果进行了融合,得到了近似统一参考框架下的速度场结果;在此基础上通过对此次地震震源区及周边地区的速度场、应变率场、基线时间序列分析,识别了震前变形特征.GPS应变率场结果显示,喜马拉雅主边界断裂存在大范围挤压应变积累,震源区处于近南北向应变积累高值过渡区.跨喜马拉雅构造带的GPS基线时间序列结果表现为持续缩短现象,表明印度板块与欧亚板块之间的持续挤压变形特征,2012年以来的缩短增强现象反映了印度板块对青藏块体的推挤增强作用明显.距离震中较近的西藏南部GPS同震位移结果以南向运动为主且指向震中,反映了青藏高原存在逆冲应变释放现象.综合此次尼泊尔地震前变形和同震应变释放特征,认为此次地震的孕震区域和同震应变释放区域均较大,将会对青藏高原的地壳变形与强震孕育产生深远影响. 相似文献
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活动构造是现今大陆地壳变形的重要反映。文中对发育于中国大陆及其邻区的活断层资料进行了系统的收集和分析整理 ,并结合活断层定量研究对主要活断层做出了较为粗略的分类。在此基础上 ,借助改进的Haines方法 (即双三次样条函数 ) ,根据中国大陆及其邻区的主要活断层资料 ,推算得出将地壳变形看作连续变形情况下的中国大陆现今地壳变形的应变率场和速度场模型。模型与现今GPS观测结果可以较好地吻合。文中还针对模型计算结果对中国大陆各区的运动矢量变化特征进行了分析 ,并通过与GPS观测结果的比较 ,定量估算出次级断裂在地壳变形中所产生的影响 相似文献