共查询到19条相似文献，搜索用时 546 毫秒
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在中国大陆及周边活动地块与活动地块边界带研究和划分的基础上,研究了中国陆区6个Ⅰ级活动地块区和22个Ⅱ级活动地块之间的共计24个活动边界带上的强震活动特征。从各边界带上强震活动的频次和单位时间、单位长度的地震应变能释放出发,讨论了各活动地块边界带的强震总体活动水平;并从震级频度关系出发,计算了各带的理论最大震级与复发周期。通过与实际地震记录对比发现,由中国大陆各主要活动地块边界带的地震活动参数(a/b)所推算的强震活动强度与实际地震活动强度总体上具有较好的一致性,强震复发期与构造活动速率则呈明显的反向变化关系,这也表明本研究给出的各边界带的a,b值具有一定的参考意义。文中还利用历史强震资料以及各带强震活动的离逝时间,基于泊松分布,探讨了各活动边界带的现今地震活动水平及其危险程度 相似文献
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中国大陆活动地块变形与地震活动的关系 总被引：4，自引：0，他引：4
本文在中国大陆及邻区活动地块研究的基础上，利用球面上的非连续变形分析方法(DDA)和近10年来的GPS测量结果，对整个中国大陆及其周边地区各活动地块的运动和变形状况进行了初步研究。研究结果表明，虽然中国大陆东西部各活动地块的运动速率和应变率相差较大，但位于同一个地块区的各个活动地块之间的运动和变形具有一定的协调性。文中还计算了活动地块边界带之间的相对运动，讨论了现今地壳运动和强震活动的关系。发现1988年以来，中国陆区的7级以上地震都发生在GPS测量所给出最大剪切应变率差异大的活动地块的边界带和现今滑动速率大的活动地块的边界断裂上。 相似文献
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《地震地质》2020,(2)
中国大陆80%以上超过7级的强震发生在活动地块边界带上,活动地块边界带已逐渐成为地震地质、地球物理、大地测量等学科重点研究的对象。文中回顾了与中国大陆活动地块边界带地震活动相关的研究结果,已有的主要认识和存在的问题包括:1)目前,在活动地块边界带地震活动领域的大部分研究工作仍然停留在统计分析层面,针对其工作基础或实际工作条件开展分析有助于深入研究中国活动地块边界带的地震活动; 2)活动地块边界带的构造运动速率决定了地震应变释放速率,但由于边界带内活动断层的复杂性,活动地块边界带的平均复发周期与构造运动速率之间的关系存在较大的不确定性,需要对这些断层系统的复杂性进行深入探讨; 3)中国大陆活动地块边界带的强震时间过程呈现出区域特征,如中国大陆东部活动地块边界带多为丛集型,青藏高原中北部地区的走滑型活动地块边界带多为准周期型,但仍需要深入研究其区域构造和区域动力学的物理机制; 4)中国大陆强震孕育发生的动力学环境整体上呈"纵向分层、横向分块"的特征,尽管随着地球物理、地球化学、大地测量、地震地质等研究的不断深入,不同时空尺度的物理模型对解释活动地块框架下大陆强震的孕育发生具有指导意义,但由于活动地块运动与变形并非只有刚性运动,壳幔介质物性的横向差异比较普遍,故对大陆型强震动力学过程的认识尚需完善,需要在活动地块理论框架下系统开展深入的研究,建立与震源物理相关的各类基础模型。 相似文献
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《地震地质》2020,(2)
由中国科学家提出的"中国大陆强震受控于活动地块运动与变形"的假说,不仅可用于解释中国大陆强震的空间分布,同时基于其理论和定义可将中国大陆划分为6个Ⅰ级活动地块和22个Ⅱ级活动地块。活动地块之间的边界带往往由活动构造带组成,一般宽约几km至百余km,是强烈地震的多发区。活动地块假说指出,已发生的近100%的8级以上强震、约80%的7级以上强震震中均位于地块边界带上。近年来,中国大陆几次7级以上强震也都发生在活动地块边界带,这不仅验证了活动地块假说的理论模型,同时还预测了未来强震就发生在活动地块边界带内某些有利于应力集中的部位。活动地块假说经过近20a的发展,已建立并逐步完善了其理论框架,奠定了中国活动构造与强震预测的理论基础,正推动着强震预测由概率预测向物理预测过渡。但就活动地块的概念和理论框架而言,还存在的诸多问题需进一步回答和解释。众所周知,强震是活动地块边界带特殊构造部位应变逐渐积累、介质突发失稳和能量释放的结果,地震预测的突破性进展需要建立在充分理解其整个物理过程的基础之上。因此,以边界带断裂的活动性、现今的变形状态、深浅构造的耦合关系、强震孕育环境及震源物理模型为主要研究内容,开展针对活动地块边界带强震活动机理与预测的研究,是活动地块理论完善和研究未来关注的重要内容和重要科学问题。 相似文献
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《国际地震动态》2020,(4)
鄂尔多斯地块及其周缘地区的地震动力学和强震危险性研究,是检验和发展活动地块理论的理想场所。近年来,伴随青藏高原动力学研究视角的不断扩大,逐渐成为国内外新的地学研究热点。项目以"丝绸之路"经济带东端、我国重点强震危险区之一的鄂尔多斯活动地块为研究对象,构建活动地块及边界带三维深浅结构和构造变形模式,建立适用于板块内部的强震孕育动力学模型,完善大陆强震孕育和发生的活动地块理论,研发具有物理意义的时间相关强震预测理论模型,提出地震危险性理论预测技术规程。我国科学家20世纪末提出的大陆强震受控于活动地块的理论,为中国大陆强震危险地点预测提供了重要理论指导,但是如何将该理论更好地应用于实际的强震危险性预测研究中,还需要进一步深入研究活动地块运动和变形如何控制边界带强震的孕育和发生过程。选择鄂尔多斯活动块为研究的目标区,重点开展以下几个方面的研究内容:地块边界带断裂活动习性与强震复发行为;地块及周缘现今三维地壳运动与应变分配;地块及边界带深部结构与深-浅构造耦合;活动地块理论完善与边界带强震危险性研究。项目执行两年来,在几个方面均取得了进展和初步成果,建立了主要边界带断裂强震复发行为模式,获得了地块及周缘不同类型现今三维地壳运动状态,建立了关键区域地块边界带深-浅构造耦合构造模型,开展了边界带强震危险性研究。 相似文献
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中国大陆的强震活动与活动地块 总被引：190，自引：6，他引：190
中国大陆晚新生代和现代构造变形以地块运动为主要特征,活动地块是被形成于晚新生代、晚第四纪(10～12万年)至现今强烈活动的构造带所分割和围限、具有相对统一运动方式的地质单元。不同活动地块的运动方式和速度是不同的,地块间的差异运动在其边界最强烈。强震是在区域构造作用下,应力在变形非连续地段不断积累并达到极限状态后突发失稳破裂的结果,活动地块边界带由于其差异运动强烈而构造变形非连续性最强,最有利于应力高度积累而孕育强震。我国大陆几乎所有8级和80％～90％的7级以上强震发生在活动地块边界带上,表明地块间的差异运动是大陆强震孕育和发生的直接控制因素。 相似文献
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中国大陆活动地块与强震活动关系 总被引：16，自引：0，他引：16
研究了中国大陆各Ⅰ级活动地块区强震活动特点, 包括强震活动的总体水平、地震应变能释放速率、震级频度关系、震源破裂特性和地震应力场特征等, 以及由GPS资料给出的各活动地块运动变形特征, 如各地块运动的速度、地块变形的应变速率、最大主压应变方向、地块运动变形中的张、压状态等. 在此基础上, 对中国陆区Ⅰ级活动地块区的强震活动特点和地壳运动变形性状进行对比研究, 给出各活动地块的构造动力环境及其运动变形的性状决定其地震活动的总体状况, 包括: 活动地块现今地壳运动变形的应变速率与地震应变能释放呈线性相关; 由震源机制给出的各活动地块的地震应力场与由GPS观测给出的现今地壳运动应变(应力)场的同一性, 以及震源破裂类型与地壳形变张、压状态的一致性等. 这些结果显示了中国大陆活动地块及其运动性状对强震孕育发生的控制作用. 相似文献
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从块体中心论的角度出发,根据中国活动地块研究的最新成果,对1977—2003年中国大陆强震成组发生的构造和震源机制特征进行了分析。结果表明,这些成组发生的强震大都位于活动地块区(Ⅰ级地块)的边界带上或活动地块区内活动地块(Ⅱ级地块)的边界带上。根据哈佛大学提供的CMT(矩张量)解,同组的强震大都具有相似的震源机制。事实表明活动地块区具有整体活动的特点,而且在动力学与运动学方面存在统一性。这些特征对认识强震成组活动的机理,缩小成组强震预测的空间范围具有现实意义 相似文献
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系统地总结分析了巴颜喀拉地块北、东、南边界带的构造特征、各个边界带上的强震活动、部分强震的震源机制解和区域地震活动,从而探讨了2010年玉树7.1级地震发生前巴颜喀拉地块地震活动特征。从2008年玉树地区地震活动变化、巴颜喀拉块体北边界和南边界强震呼应及块体动力学过程进行了地震趋势预测的思考。 相似文献
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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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A STUDY REVIEW ON CHARACTERISTICS OF SEISMIC ACTIVITY OF ACTIVE-TECTONIC BLOCK BOUNDARIES IN MAINLAND CHINA 
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下载免费PDF全文 More than 80 percent of strong earthquakes(M≥7.0)occur in active-tectonic block boundaries in mainland China, and 95 percent of strong earthquake disasters also occur in these boundaries. In recent years, all strong earthquakes(M≥7.0)happened in active-tectonic block boundaries. For instance, 8 strong earthquakes(M≥7.0)occurred on the eastern, western, southern and northern boundaries of the Bayan Har block since 1997. In order to carry out the earthquake prediction research better, especially for the long-term earthquake prediction, the active-tectonic block boundaries have gradually become the key research objects of seismo-geology, geophysics, geodesy and other disciplines. This paper reviews the research results related to seismic activities in mainland China, as well as the main existing recognitions and problems as follows: 1)Most studies on seismic activities in active-tectonic block boundaries still remain at the statistical analysis level at present. However, the analysis of their working foundations or actual working conditions can help investigate deeply the seismic activities in the active-tectonic block boundaries; 2)Seismic strain release rates are determined by tectonic movement rates in active-tectonic block boundaries. Analysis of relations between seismic strain release rates and tectonic movement rates in mainland China shows that the tectonic movement rates in active-tectonic block boundaries of the eastern region are relatively slow, and the seismic strain release rates are with the smaller values too; the tectonic movement rates in active-tectonic block boundaries of the western region reveal higher values, and their seismic strain rates are larger than that of the eastern region. Earthquake recurrence periods of all 26 active-tectonic block boundaries are presented, and the reciprocals of recurrence periods represent high and low frequency of seismic activities. The research results point out that the tectonic movement rates and the reciprocals of recurrence periods for most faults in active-tectonic block boundaries exhibit linear relations. But due to the complexities of fault systems in active tectonic block boundaries, several faults obviously deviate from the linear relationship, and the relations between average earthquake recurrence periods and tectonic movement rates show larger uncertainties. The major reason is attributed to the differences existing in the results of the current earthquake recurrence studies. Furthermore, faults in active-tectonic boundaries exhibit complexities in many aspects, including different movement rates among various segments of the same fault and a certain active-tectonic block boundary contains some parallel faults with the same earthquake magnitude level. Consequently, complexities of these fault systems need to be further explored; 3)seismic activity processes in active-tectonic block boundaries present obvious regional characteristics. Active-tectonic block boundaries of the eastern mainland China except the western edge of Ordos block possess clustering features which indicate that due to the relatively low rate of crustal deformation in these areas, a long-time span is needed for fault stress-strain accumulation to show earthquake cluster activities. In addition, active-tectonic block boundaries in specific areas with low fault stress-strain accumulation rates also show seismic clustering properties, such as the clustering characteristics of strong seismic activities in Longmenshan fault zone, where a series of strong earthquakes have occurred successively, including the 2008 M8.0 Wenchuan, the 2013 M7.0 Lushan and the 2017 M7.0 Jiuzhaigou earthquakes. The north central regions of Qinghai-Tibet Plateau, regarded as the second-grade active-tectonic block boundaries, are the concentration areas of large-scale strike-slip faults in mainland China, and most of seismicity sequences show quasi-period features. Besides, most regions around the first-grade active-tectonic block boundary of Qinghai-Tibet Plateau display Poisson seismic processes. On one hand, it is still necessary to investigate the physical mechanisms and dynamics of regional structures, on the other hand, most of the active-tectonic block boundaries can be considered as fault systems. However, seismic activities involved in fault systems have the characteristic of in situ recurrence of strong earthquakes in main fault segments, the possibilities of cascading rupturing for adjacent fault segments, and space-time evolution characteristics of strong earthquakes in fault systems. 4)The dynamic environment of strong earthquakes in mainland China is characterized by “layering vertically and blocking horizontally”. With the progresses in the studies of geophysics, geochemistry, geodesy, seismology and geology, the physical models of different time/space scales have guiding significance for the interpretations of preparation and occurrence of continental strong earthquakes under the active-tectonic block frame. However, since the movement and deformation of the active-tectonic blocks contain not only the rigid motion and the horizontal differences of physical properties of crust-mantle medium are universal, there is still need for improving the understanding of the dynamic processes of continental strong earthquakes. So it is necessary to conduct in-depth studies on the physical mechanism of strong earthquake preparation process under the framework of active-tectonic block theory and establish various foundation models which are similar to seismic source physical models in California of the United States, and then provide technological scientific support for earthquake prevention and disaster mitigation. Through all kinds of studies of the physical mechanisms for space-time evolution of continental strong earthquakes, it can not only promote the transition of the study of seismic activities from statistics to physics, but also persistently push the development of active-tectonic block theory. 相似文献
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华北地区是我国的政治、 经济和文化中心, 也是我国地震多发地区之一。 华北地区历史地震资料记载时间较早且较为连续, 是研究我国强震活动的理想试验场。 选取第三、 第四活动期M≥6.0地震目录作为基础资料研究华北地区强震活动特点。 首先探讨华北地区强震活动与活动地块、 边界带的关系, 然后从时间和空间上分析华北地区强震活动的轮回性阶段及其期幕活动特点, 最后计算未来5年华北地区发生下一次M≥6.0地震的累积概率和条件概率。 研究结果表明: ① 华北地区M≥6.0地震活动主要集中在活动地块的边界带, M≥7.0地震则全部发生在活动地块的边界带上, 同时华北地区地震应变释放速率与边界带的构造活动速率呈线性相关; ② 第四活动期各活跃幕的能量释放均低于第三活动期, 因此华北地区未来仍可能发生M≥6.0地震; ③ 第三、 第四活动期的主体活动区存在显著差异, 且第四活动期的强震活动较第三活动期向东迁移; ④ 在2020年年初发生第四活动期闭幕M≥6.0地震的累积概率为80%左右, 而在2022年年底前发生M≥6.0地震的条件概率为50%。 本研究可为华北地区地震大形势分析和中长期地震危险性预测提供重要参考。 相似文献
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藏东南及周边地区地震活动特征研究 总被引：1，自引：0，他引：1
藏东南及周边地区是印度板块与欧亚板块动力碰撞的影响区, 该区历史地震活动强烈, 曾发生过1950年墨脱—察隅8.6级和1951年当雄8.0级地震。 本文首先介绍藏东南及周边地区的地质构造背景, 其次通过考察该地区强震活动情况和活动地块边界带相关段落的加卸载响应比(LURR)时序特征, 分析了研究区的强震活动状态。 从历史地震活动看, 安达曼弧地区与喜马拉雅东构造结地区强震活动存在一定的动力关联, 当前研究区域的周边动力环境表现为安达曼弧地区地震活动强烈和东构造结地区的持续平静。 从地震活动图像看, 1980年以来6级以上地震在藏东南及周边地区已经形成空区, 表现类似于1950年墨脱—察隅地震前的空间分布特征。 从活动地块边界带相关段落LURR时序特征看, 喜马拉雅带东段现处于高应力状态, 其次为澜沧江带与三江带。 相似文献
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通过计算前人研究所给出的中国大陆26条活动地块边界带上地震过程的变异系数, 分析了各边界带的地震活动类型, 结果表明中国大陆东部地区的边界带地震都表现为丛集过程, 西部地区大多是泊松过程或者准周期过程, 尤其是大陆板块俯冲作用强烈的边界带上地震活动主要呈现为泊松过程, 青臧高原北部和东部地区的边界带都表现为准周期过程, 并讨论了可能的物理机制。 并在以往研究的基础上, 基于对数正态分布函数, 计算了各边界带目前地震发生的累计概率以及未来五年内地震发生的条件概率, 探讨了各活动地块边界带的危险程度等。 相似文献
17.
《地震研究进展（英文）》2023,3(1):100177
The long-term earthquake prediction from 2021 to 2030 is carried out by researching the active tectonic block boundary zones in the Chinese mainland. Based on the strong earthquake recurrence model, the cumulative probability of each target fault in the next 10 years is given by the recurrence period and elapsed time of each fault, which are adopted from relevant studies such as seismological geology, geodesy, and historical earthquake records. Based on the long-term predictions of large earthquakes throughout the world, this paper proposes a comprehensive judgment scheme based on the fault segments with the seismic gap, motion strongly locked, sparse small-moderate earthquakes, and apparent Coulomb stress increase. This paper presents a comprehensive analysis of the relative risk for strong earthquakes that may occur in the coming 10 years on the major faults in the active tectonic block boundary zones in the Chinese mainland. The present loading rate of each fault is first constrained by geodetic observations; the cumulative displacement of each fault is then estimated by the elapsed time since the most recent strong earthquake. 相似文献
18.
Previous studies have shown that the active tectonic block boundaries in the Chinese mainland are the main belts and concentration areas of strong earthquakes occurring in the Chinese mainland.It is essential to carry out follow-up analysis of strong earthquake risk of active tectonic block boundaries.In this paper,we carry out the analysis on the tendency of strong earthquakes along each active tectonic block boundary from three aspects respectively,including the evolutionary characteristics of the Load/Un... 相似文献
19.
ZHENG Wen-jun WANG Qing-liang YUAN Dao-yang ZHANG Dong-li ZHANG Zhu-qi ZHANG Yi-peng 《地震地质》1979,42(2):245-270
The hypothesis that strong earthquakes in China mainland are controlled by the movement and interaction of active-tectonic blocks was advanced by Chinese scientists, with the remarkable ability to encompass geological and geophysical observations. Application of the active-tectonic block concept can illustrate 6 active-tectonic block regions and 22 active-tectonic blocks in mainland China and its neighboring regions. Systems of active-tectonic block boundaries are characterized by a zone of decades or hundreds of strong earthquakes. One of the greatest strengths of the modern active-tectonic block hypothesis is its ability to explain the origin of virtually all the M8 and 80% M7 earthquakes on the main continent in eastern Asia. In other words, active-tectonic block boundary stands in strong causal interrelation with recurrence behaviors of strong earthquakes and thus, it is possible to predict an earthquake occurrence in principle. After nearly two decades of development and improvement, the active-tectonic block hypothesis has established its theoretical foundation for the active tectonics and earthquake prediction, and is promoting the transition from probabilistic prediction to physical prediction of strong earthquakes. The active-tectonic block concept was tested by application to a well-documented, high-frequent earthquake area, and was found to be an effective way of describing and interpreting the focal mechanism and seismogenic environment, but there are still many problems existing in the active-tectonic block hypothesis, which confronts with rigorous challenges. Future progress will continue to be heavily dependent on the high-precision synthetic seismogram, especially of critical poorly documented settings. It is well known that strong earthquakes occur anywhere in the interactions among the active-tectonic block boundaries where there is sufficient stored elastic strain energy driving fault propagation, and then releasing the stored energy. Therefore, future studies will focus on the mechanism and forecast of the strong earthquake activity in the active-tectonic block boundary zone, with fault activity within the active-tectonic block boundary zone, quantifying current crustal strain status, upper crust and deep lithosphere coupling relation, strong earthquake-generating process and its precursory variation mechanism in seismic geophysical model as the main research contents, which are the key issues regarding deepening the theory of active-tectonic block and developing continental tectonics and dynamics in the modern earth science. 相似文献