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目前对强震迁移的研究多是集中在发现迁移现象方面,一些总结迁移规律的尝试则较为主观。本文认为,强震迁移如果具有规律性则其迁移指标应具有某种统计意义,并且对整体数据集的统计分析可避免传统迁移分析方法中的问题。通过对华北地区强震迁移的3个指标(迁移方位、迁移距离、迁移时间)的统计分析,表明研究地区存在较明显的优势迁移方向(西偏南—东偏北方向)、优势迁移距离(100km内以及300~700km范围)和优势迁移时间间隔(1年内以及3~4年内),不同震级范围以及不同活跃期内的迁移特征略有区别。 相似文献
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Qin Chengzhi ) Zhou Chenghu ) Pei Tao ) Li Quanlin ) )State Key Laboratory of Resources Environmental Information System Institute of Geographic Sciences Natural Resources Research CAS Beijing China )Institute of Geophysics CEA Beijing China 《中国地震研究》2004,(2)
INTRODUCTIONMigrationofstrongearthquakesisaphenomenonwherebystrongearthquakestakeplaceinsuccessionincertainspatiallyregularpatterns (ZhangGuomin ,etal,2 0 0 1 ) .Seismologistsintheworldhavenoticedthisphenomenonforalongtime .Manyinstanceswerediscoveredinthepastdecades ,suchasthemigrationofstrongearthquakesalongtheNorthAnatolianFaultinTurkeysince1 939(Richter,1 958)andthemigrationofaseriesofearthquakes (MS ≥ 6 0 )aftertheMS7 9earthquakeinKwandong ,Japan (Utsu ,1 987) .Theexamplesofre… 相似文献
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Based on research result concerning the preparation and activity of strong earthquakes in groups and using the finite element method, a finite element dynamic model for Southwest China is established in this paper. Using this model, the stress adjustment in the whole of the Southwest China region in response to the stress change due to strong earthquake occurrence is studied. The preliminary result shows that many strong earthquakes occurred in areas where the stress heightened after the last strong earthquake. So, the finite element model set up in this paper is useful for judging the regions where strong earthquakes are likely to occur in future. 相似文献
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计算了1587年以来的华北地区200个5级以上地震发生日的月相,其结果表明二者的相关性不明显,但分布在华北境内的中国东部重力梯级带上的101个较强地震,却与朔望日有着较密切的关系。 相似文献
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Yang Zhu'en Wang Liangmou and Han ZhujunInstitute of Geology State Seismological Bureau Beijing China 《中国地震研究》1998,(1)
The tectonic conditions for strong earthquakes are complicated in various aspects.The genetic conditions for strong earthquakes were studied from the angle of various disciplines.About 20 conditions belonging to different fields have been described by predecessors.In this paper,the authors try to study and evaluate all the tectonic condition factors for strong earthquakes by the methods of fuzzy mathematics and hierarchical analysis.Taking the northern part of North China as an example,the authors make a comprehensive digital analysis of all the quantitative and semi-quantitative tectonic factors.The credibility values of all strong earthquakes with different magnitudes are given after statistical analysis and calculation.Forty-one fault zones in the study region are quantitatively analyzed,and the potential seismogenic fault zones,maximum magnitude,and risk of earthquake occurrence in the near future are assessed.The result of synthetic evaluation,based on all tectonic conditions of different categorie 相似文献
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由跨断层形变测量反映的华北地块近期断裂活动特征 总被引:3,自引:0,他引:3
通过对华北地块不同构造部位、不同地震活动时段的跨断层测量资料研究表明,华北地块对于NE走向断裂作用为主的构造单元(包括地块和边界带)的强震活跃时段的断层运动速率明显小于强震不活跃时段;对于NW走向断裂作用为主的构造单元,其强震活跃时段的断层运动速率明显大于强震不活跃时段;对于NE、NW走向断裂共同作用的构造单元,断层运动速率变化特征类似于NW走向断裂作用为主的构造单元。结果还表明,华北地块现今强震活动主要受NW走向断裂的控制。 相似文献
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太阳活动与华北强震关系的分析 总被引:10,自引:2,他引:8
统计了太阳黑子活动11年周期和22年周期与华北地区(E108°~124°,N34°~42°)1815年~2002年187年6级以上强震的关系。结果显示,它们之间存在着较好的对应关系,华北地区的强震自1815年第4高潮以来,有84.6%的强震集中在太阳黑子11年变化周期的峰年段(±1年)和谷年段(±1年)内发生;其中尤以双周峰年段、单周谷年段较为集中;而单周下降时段却从未有过强震发生。目前正处于太阳黑子活动第23周单周峰年之后的下降时段,该统计区内强震发生的概率极低。 相似文献
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剪切波速是区别土动力学和静力学的重要参数,其影响因素包括土层埋深、颗粒形状、颗粒比重、压缩模量、孔隙比、含水率和密度等,其中土层埋深对剪切波速的变化影响较大。本文搜集整理了华北地区10个城市的928个钻孔共10703个测点的剪切波速与土层埋深之间的经验统计关系,探讨华北地区剪切波速随深度变化的特征,并从岩性条件、沉积环境等方面分析其原因。通过对比分析,给出了华北地区黏性土和砂类土剪切波速随深度变化的最佳拟合经验统计关系,并进行实例验证,所得结果可为缺乏数据的区域提供一定参考。 相似文献
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Yang Guohua 《中国地震研究》2004,18(2):114-124
Based on high-precision data obtained in the past decade from GPS re-measurement in the North China Network, the Crustal Movement Observation Network of China (CMONOC) and GPS measurement along the Shanxi graben zone, the status and evolution of horizontal crustal movement in the North China region are analyzed. The results show that (1) the Yanshan tectonic zone (Zhangjiakou-Bohai Sea zone)is an active one with the largest horizontal strain in the North China region; The largest tendency differential movement of adjacent blocks is seen between the Yanshan block and the North China plain block; about 2mm/a (left lateral) ; (2)The significant horizontal differential movement along the boundaries of the North China region is characterized by right-lateral strike-slip movement at the middle-north segment on its west boundary (composed of Yinchuan and other active tectonic zones) and compressive movement at the south segment; while the Yinshan rift zone located along the west segment on its north boundary is dominated by tensile movement. Other boundaries and zones have no obvious differential movement; (3) On the whole, measurements of each period differ from one another, which might result from the nonlinear movement component as well as from the error effect. In the paper, results of the relative movement and strain in different periods are given for different blocks and boundary zones. 相似文献
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南华北盆地与秦岭大别造山带在构造上有耦合关系,地震活动水平相当。将南华北盆地和秦岭大别造山带组成的南华北地区作为研究对象,考察了其地震活动特征和青藏高原强震对其影响作用。发现南华北地区地震活动水平显著低于北华北地区,略低于下扬子地区。并且,通过对比分析青藏块体7.0级以上地震和南华北地区4.0级以上地震的对应关系,发现两个地区之间存在明显的成组对应现象,并表现2年左右的时间差,表明青藏块体的地震活动对南华北地区有明显的构造应力场传递作用。该结果为南华北地区中长期地震预测提供依据。2017年四川阿坝州九寨沟县发生7.0级地震,根据时间延迟的存在,对南华北地区未来中等地震的发生具有一定的指示意义。 相似文献
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基于小波分析提取的云南强震数字化形变异常特征 总被引:2,自引:0,他引:2
运用小波分析理论及其时频分析方法,阐述了提取高频信息与低频信息的方法,并用该方法提取了2001年以来云南地区强震(MS≥6)前数字化形变异常。结果表明,在MS≥6地震前,震中附近(<250km)的倾斜、应变和重力等形变信号出现周期为3~11天的异常信息;重力和倾斜异常出现较早,可作为中短期指标,应变异常出现较晚,可用作短临指标;震源区最先出现应变异常,应变异常可作为未来强震震中的判定指标。这些强震前数字化形变异常特征对该地区未来强震三要素的中短临判定具有较好的参考作用。 相似文献
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The accuracy of b-value is limited by the uncertainty of the magnitude.In order to improvethe accuracy of the b-value,a statistic methodology was used to estimate the number of eventsbased on that there are several magnitude values for one historical event by several methods toestimate the magnitude.The b-value and seismic strain rates were calculated for the threeregions in the North of China.The method proved to be valid for all the regions,especiallyfor the data with large fluctuation.In order to study the stress state,the strain rate tensorand the principal axes of tension and compression were calculated for each of three regions bythe data of the focal mechanism,finally the stress state in each region was discussed. 相似文献
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Migration of strong earthquakes (M≥ 7.0) along the North-South Seismic Belt of China since 1500 AD shows three patterns: Approximately equal time and distance interval migration from N to S, varied patterns of migration from S to N and grouped strong earthquake activity in a certain period over the entire seismic belt. Analysis of strong earthquakes in the past hundred years shows that the seismicity on the North-South Seismic Belt is also associated with strong earthquake activities on the South Asia Seismic Belt which extends from Myanmar to Sumatra, Indonesia. Strong earthquakes on the former belt often lag several months or years behind the quakes occurring on the later belt. So, after the occurrence of the December 26, 2004 Ms8.7 great earthquake off the western coast of Sumatra, Indonesia, the possibility of occurrence of strong earthquakes on the North-South Seismic Belt of China cannot be ignored. The abovementioned migration characteristics of strong earthquakes are related to the northeastward collision and subduction of the India Plate as well as the interaction between the Qinghai-Xizang (Tibet) Plateau and the stable and hard Ordos and Alashan Massifs at its northeastern margin. 相似文献