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众所周知,地震的频度-震级统计关系满足古登堡-里克特关系式。易知,这一关系是分形的,分维数D=1.8~2.0。既然每条断层都有其特征地震这一观点已被普遍接受,那么断层的频数-尺度统计关系也将是分形的。有限的野外研究表明,断层的出露部分是D≈1.6的二维分形(地震和断层的分维数并不要求一定相等,因为地震的复发时间亦具有依赖于标度的幂律关系)。断块在很宽的尺度范围内具有D≈2.5的分形频数-尺度关系。关于构造形变的一个模型就是碎裂,这样一个标度不变的模型似乎与上述讨论的分形关系是一致的。地震活动性具有许多“自组织临界现象”的显著特性,能量(应变)被持续不断地施加于地壳上,又以离散事件的形式(地震)被释放掉,而这些离散的事件具有分形的频数-尺度分布。这样,认为大陆地壳的所有地方均处于这样一种临界状态似乎是有道理的(类似于与完全塑性有关的临界应力),其证据来源于板内地震的分布,以及差不多是任何一个地方的人工水库蓄水后所发生的诱发地震。 相似文献
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通过对涞源、大灰厂、牛口峪、赤城、太原等台的地形变资料进行系统辨识和研究,认为带控制项的自回归模型(简称CAR(n)模型)能够较为客观地、合理地反映迭加了温度、降雨等影响的地壳形变观测系统。将所得模型用于资料预估,排除干扰,识别地震异常,效果较为理想。 相似文献
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川滇地区现今地壳形变及其与强震时空分布的相关性研究 总被引:3,自引:1,他引:3
本文通过分析80年代以来的川滇地区跨断层形变测量资料、区域垂直形变测量资料及部分大区域GPS测量资料,认为该时间域内川滇地区地壳形变处于相对弱状态,并直接导致了自1981年道孚6.9级地震后至今川滇地区6级以上地震基本上未沿主边界断裂展布,且具有准顺时针旋转迁移的分布特征。基于此,认为未来几年内川滇地区地震危险性预测研究的重点应是川滇地区中部。最后根据现今地壳形变测量资料和地震分布特征提出了川滇地区活动地块时段性划分的概念,并给出了初步的划分结果。 相似文献
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自20世纪80年代中期以来,GNSS技术在高精度地壳运动观测与构造形变研究中取得了丰硕的成果,为大地测量、地球动力学研究和防震减灾等诸多领域的业务深化和应用拓展提供了强大的技术支撑。本文在回顾中国大陆地壳形变GNSS站网发展历程的基础上,阐述该网络产出的中国大陆长期构造运动速度场、中国大陆应变率场、位移时间序列、基线时间序列和多边形应变时间序列等几类基础产品,分析这些产品在中国大陆构造运动动态趋势和地震预测分析中的应用情况以及所面临的瓶颈问题,最后展望未来GNSS在高精度地壳运动监测应用中的发展方向。以中国大陆构造环境监测网络为基础,大力推进国内海量GNSS观测数据的共享,提升GNSS多系统融合定位精度,将产出更为精细的科学产品,更好地服务于中国大陆地壳运动和地震预测分析等研究。 相似文献
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Guo Liangqian 《中国地震研究》2000,14(4):312-322
In the paper, the current strain field and stress field in Chinese continent have been discussedbased on the processed data from two GPS campaigns of national GPS network carried out inthe years of 1994 and 1996. With a principal compressional strain direction of NNE, thewestern and castern parts of Qinghai-Xizang subplate are dominated by extensional straiu andthe central Part by compressional strain. Along the southwestern segment of southeastern partof Qinghai-Xizang subplate, i. e. Yunnan area, the princiPal compressional strain direction isNW and the compressional strain is equivalent to the extensional strain in magnitude. Theprincipal compressional strain of Xinjiang subplate is mainly NNE and NE with a difference inthe strain magnitude. The principal compressional strain in North China subplate is quite effective in NE and nearly EW directions with differences along some segments. However, thecompressional strain is corresponding to the extensional strain in magnitude in most areas. Theprincipal 相似文献
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对中国大陆地壳水平变形的初步探索 总被引:13,自引:0,他引:13
根据全国GPS网1994和1996年两期观测资料的处理结果,讨论了中国大陆地区现阶段应变场和应力场。青藏亚板块的西部和东部张应变起主导作用,中部压应变占优势,主压应变方向为北北东向;青藏亚板块东南部东南段云南地区的主压应变方向为北西向,压应变和张应变量级相当。新疆亚板块的主压应役北北东向至北东向为主,应变量存在差别。华北亚板块的主压应变方向是北东至近东西向为主导,局部地段存在差别,大部分地区压应变 相似文献
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地壳形变与地震前兆探索回顾和展望 总被引:2,自引:0,他引:2
本文回顾了我国地震预报中地壳形变观测技术、 数据处理方法和软件及地壳形变前兆观测研究进展。 1966年邢台地震后, 我国地震预报工作经历了难得的成功、 更多惨痛失败和“地震不可预报论”等干扰, 发展曲折。 尽管2008年汶川和2011年东日本大地震预报失败,但这两次和其他大地震前后GPS和其他观测得到的地壳形变表明, 大地震是有前兆的, 是可以预报的。 比较了我国地震预报所采用的主要的地形变观测技术和分析方法, 讨论了观测和数据处理方法的特点, 简要介绍了地壳形变地震前兆新近的研究结果, 重点阐述了GPS观测技术多方面的优势。 事实证明, GPS观测得到的汶川大地震前的形变异常或前兆, 是我国地壳形变观测与地震前兆探索最突出的成果。 相似文献
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Analysis of deformation data measured across the faults, regional vertical deformation data and GPS measurements in the Sichuan-Yunnan region made since the 1980s permitted us to conclude that the crustal deformation in the region during this period of time was relatively weak and caused the occurrence of earthquakes (Ms≥6.0), which were not distributed along the major boundary active faults in the region after the 1981 I)awu Ms 6.9 earthquake and that the seismic activity is characterized by quasi-clockwise migration. Thus, it follows that earthquake prediction research should be focused on the central part of the Sichuan-Yunnan region in the coming years. Finally, a concept of temporal division of the region into active blocks is suggested and the preliminary result of the division is given in the paper. 相似文献
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Based on data from an across-fault survey along the sichuan-Yunnan rhombic block boundaries,the recent deformation characteristics on each fault have been analyzed.It was found that the rate of crustal deformation is slowing down along the northern segment and increasing along the southern segment.Each fault has different features of deformation.The horizontal deformation is mainly characterized by left-lateral strike-slip.The rate of vertical deformation is less than that of the horizontal dformation.The faults have the feature of upper wall uplifting alternated with descending.The anomaly changes of crustal deformation at some sites are closely related to the seismicities near the sites. 相似文献
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分析了1991年3月26日大同—阳高5.8Ms地震与1989年10月大同—阳高6.1Ms震群的关系,认为这两次地震属于同一类震群.介绍了这次地震前赤城台石英摆倾斜仪、太原台目视水管倾斜仪和阳原台金属摆倾斜仪的异常情况.从两次地壳形变异常的异同映证了两次地震属同一震群.同时也说明利用地壳形变资料预报地震是有希望的. 相似文献
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Calculation of repeated observation data at the densified GPS monitoring network in northeastern area of Pamir together with data from IGS stations in the peribphyery of the area yielded the movement rate of more than 40GPS station sites in the area,and,hence,the recent crustal deformation rate pattern and time series of fiductial GPS stations in the area were obtained.The result indicates that the principal movement direction of the GPS station sites is NNW,basically diagonal to the strike of Tianshan fold belt,i.e.a normal compression occurs in the Tianshan region.The movement pattern near Jiashi and its southwestern zone is some different from that of station sites in their surrounding areas,indicating a certain relation of tectonic deformation in Jiashi area to seismic activity during last years.The movement rate of station sites in the periphery of Taim basin less varies and its direction is basically consistent It indicates less or basically no deformation within Tarim basin. 相似文献