共查询到18条相似文献，搜索用时 157 毫秒
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通过对南北带1999~2001、2001~2004年GPS资料的处理与分析,结果显示:南北地震带是我国水平运动的转化带与形变带;差异活动最显著的断裂带是川滇菱形块体的东边界带和青藏高原东北缘(祁连带);动态活动最突出的地区是川滇地区。其形变相对突出的地域主要位于川滇块体的东北界和西南端,变形指数最大为2.5~3.5,而其它地区一般在1.5以内。所以,川滇地区是现在乃至今后一段时间内可能成为的重点孕震地区,我们应给予重点关注。 相似文献
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昆仑Ms 8.1地震前青藏块体北、东缘水平运动变形的关联特征 总被引：2，自引：0，他引：2
青藏块体东北缘和川滇GPS监测区1991(1993)、1999和2001年高精度GPS观测资料揭示：2001年11月14日昆仑Ms8．1地震前，青藏块体北、东缘构造区域水平运动变形场动态演变具有一定的关联性特征。即：在继承性运动总体背景下，临近大震发生时两区域运动强度同步减弱且变形状态发生变化。结合地质构造分析研究认为，昆仑Ms8．1地震前，青藏块体边界运动变形的关联性变化与大震孕育后期大范围应力应变快速积累所形成的扰动应力场有关；随着块体内部大震的发生、应变能的大量释放和构造应力场的调整，可能会促使块体边界地带具有较高应变积累的相关构造部位(尤其是未被历史强震破裂贯通的地带)的应力应变的进一步积累或破裂释放。 相似文献
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对永胜6级地震的预报及依据 总被引：2，自引：1，他引：2
2001年10月27日在云南永胜发生6.0级地震，震前四川省地震局有较准确的中期和短临预报，加强了川滇交界地区的地震监测预报工作，并且向四川省政府作了汇报，取得了明显的社会效益。经验性地震预报重视川滇菱形地块西界断裂带动态活动图像的分析，尤其对历史强震破裂空段附近出现的中小震活动带或新活跃区段的研究；同时，重视4级前震群、川滇交界地区地下水位、水温、形变观测异常的跟踪分析和震情预测。 相似文献
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为了从整体上(较大尺度)跟踪区域应变场的时空变化,并更客观地描述区域运动场,文中在区域无旋转的基础上使用了以提取中低频应变信息为主的连续非线性应变模型。根据《中国地壳运动观测网络》位于川滇地区GPS测站所产生的复测资料(1999年~2001年~2004年),以1999年~2001年的运动为基本参考(阶段性形变背景),从2001年和2004年两期资料中分离出了2001年昆仑山8.1级地震对其产生的主要影响量。结果表明:①昆仑山8.1级地震对川滇地区产生了可识别的影响,且形变的方式与形变背景既有一定的相似性又有一定差异;②震前运动场非常有序;震后的位移场有序与杂乱并存,GPS测站的位移量一般为数毫米;③震前的主应变场基本为近东西向显张性、南北向显压性,且以张性为优势;震后四川地区基本上为东西向压、南北向张,且以压性为优势,云南地区北东向张、北西向压,且以张性为优势;④震前面应变以膨胀为主,收缩区基本位于川滇块体的东界及附近地区;震后四川地区为面收缩地区(越往北越大),南部为面膨胀地区。从整体上看,昆仑山8.1级地震对川滇地区能量的积累有积极作用,重点应注意西昌-东川段及附近地区。 相似文献
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Based on the GPS velocity field data of 1999-2007 and 2011-2013,we used the least squares configuration method and GPS velocity profile results to synthetically analyze the dynamic evolution characteristics of crustal deformation in the Yunnan area before and after the Wenchuan earthquake. The dynamic evolution of GPS velocity field shows that the direction is gradually changed from the south in the southern part of the Sichuan-Yunnan block to the south-west in the southern Yunnan block and there is a clear relative motion characteristic near the block boundary fault zone. Compared with the GPS velocity of 1999-2007, the results of 2011-2013 also reflect segmental deformation characteristics of the block boundary fault zone. Southeast movement shows a significant increase, which may be related to crustal deformation adjustment after the Wenchuan earthquake. The dynamic evolution of strain parameters shows a pattern of "extension in the middle and compression at both ends" in the whole area and the distribution of deformation (shear, extension or compression) is closely related to the background motion and deformation characteristics of the main fault zone. Compared with the results of the period of 1999-2007, the extensional deformation zone of 2011-2013 is expanded eastward and southward. The compressional deformation of the eastern boundary (the Xiaojiang fault zone) of the Sichuan-Yunnan block is no longer significant, which is mainly concentrated in the northern section of the Xiaojiang fault zone and may be related to the post-seismic deformation adjustment of the Wenchuan earthquake. The GPS velocity profile results show that the left-lateral slip velocity of the Xiaojiang fault zone reduced gradually from north to south (10mm/a-5mm/a), and the width of the northern section is wider. The right-lateral slip rate of the Honghe fault zone is about 4mm/a, and the deformation width is wider. The dynamic results show that the Wenchuan earthquake has little effect on the deformation modes of these two fault zones. 相似文献
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Pattern of latest tectonic motion and its dynamics for active blocks in Sichuan-Yunnan region, China 总被引：9，自引：0，他引：9
Based on the concept of "active blocks" and spatial distribution of historical earthquakes with surface ruptures as well as major and subordinate active faults. The Sichuan-Yunnan region can be divided into four first-order blocks. They are the Markam block (I), the Sichuan-Yunnan rhombic block (II), Baoshan-Pu'er block (III), and Mizhina-Ximeng block (IV). Cut by sub-ordinate NE-trending active faults, the Sichuan-Yunnan rhombic block (II) can be further divided into two sub-blocks: the northwestern Sichuan sub-block (II1) and the middle Yunnan sub-block (II2), while the Baoshan- Pu'er block (III) can be further divided into three sub-blocks: Baoshan sub-block (III1), Jinggu sub-block (III2), and Mengla sub-block (III3). A quantitative study of offset landforms is carried out and the basic types of active faults and their long-term slip rates along the major boundaries of active blocks of different orders in the Sichuan-Yunnan region are determined, through slip vector analysis, the motion states of the active blocks are clarified and the deformation coordination on the block margins is discussed. It is suggested that the tectonic motion of the blocks in this region is a complex or superimposition of three basic types of motions: southeastward sliding, rotating on vertical axis, and uplifting. The Markam block (I), the northwestern Sichuan sub-block (II1), and middle Yunnan sub-block (II2) have a southeastward horizontal sliding rate of 1-5 mm/a, clockwise rotating angular rate of 1.4-4(/Ma, and uplifting rate of about 1 mm/a. The Baoshan-Pu'er (III) and Mizhina-Ximeng (IV) blocks have also been extensively clockwise rotated. This pattern of motion is a strain response to the collision between the Indian and Eurasian plates and the localized deformation and differential slip on the block margins associated with the northward motion of the Indian Plate. Because a set of transverse thrusts between the blocks absorbs and transforms some components of eastward or southeastward sliding motion, the eastward escape or extrusion of the Tibetan Plateau is limited as "imbricated thrusting transformation-limited extrusion model". 相似文献
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利用青藏块体东北缘地区13、1年GPS观测资料，给出了本区地壳水平运动速度场及视应变场分布图，提出了由位移观测值直接求解块体旋转和变形参数的方法，初步研究了本区构造块体运动与变形特征.结果表明：①本区存在整体性向东-东南方的运动(速率约mm/a)；②南部的甘肃-青海块体的运动较快，而北部的阿拉善块体的运动较慢，二者运动速率相差近6mm/a，祁连-海原断裂带左旋走滑运动显著.③自西向东存在北北东-北东东向压性运动；④阿拉善块体、甘肃-青海块体内部存在北西西向张性变形，阿拉善块体的整体张性变形更显著，鄂尔多斯块体西侧的块体交接地带为压性运动. 相似文献
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利用GPS资料研究郯庐带现今运动及变形状态 总被引：2，自引：0，他引：2
本文利用华北地区1999—2001年, 2001—2004年, 2004—2007年及2007—2009年四期GPS速度场资料, 基于块体的整体旋转与均匀应变模型, 分析了郯庐断裂带中南段的运动及变形特征。 结果显示: 潍坊—郯城段主要为右旋走滑的变形特征, 而郯城—庐江段则为左旋滑动的变形特征, 两段垂直断层方向上的变形表现为“张压交替”的特征。 基于刚体运动模型, 计算了扣除环渤海湾区域整体刚性运动的华北地区GPS速度场, 并分析了环渤海湾区域块体的变形状态, 结果显示环渤海区虽然各期的变形特征不同, 特别是郯庐带附近, 各期的运动特征差异较大, 但基本可反映燕山—渤海地震带是运动特征差异的分界线, 且每期郯庐带各站点的一致性运动明显。 相似文献
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Introduction The Global Position System (GPS) may provide information about the crust movement of high precision in a large area, which significantly improve the capability of monitoring crustal movement over the area. In the last decade, studies on the global plate movement, the large scale block motions, the high-resolution crust movement of related monitored regions and tectonic de-formation fields have become the hotspot of spatial geodesy (ZHU et al, 2003; Wang et al, 2001; HUANG et… 相似文献
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根据活动断裂分布和区域流变结构建立川滇地区三维有限元模型， 采用上地壳为弹性介质，下地壳和上地幔为Maxwell体的粘弹性模型，模拟川滇地区地壳现今运动和应力分布，探讨川滇地区地壳运动变形的动力学机制. 通过4种不同边界条件和深度分层结构有限元模型的计算结果的对比，认为川滇地区绕喜玛拉雅东构造结顺时针旋转的地壳运动模式主要受川滇地区特殊的边界动力作用控制，川滇菱形块体下地壳流动对上地壳的拖曳作用亦不容忽视. 同时，川滇地区各块体的现今地壳运动场和应力场还受到区域主要活动断裂带的影响， 呈现分块特征. 相似文献