共查询到19条相似文献，搜索用时 62 毫秒
1.
青海昆仑山口西 8.1级地震发生在具有新生性特征的可可西里—东昆仑活动断裂带上。该断裂带在 190 0年以来的 10 0多年中经历了一个强震活动过程。在该强震活动过程中 ,地震沿整个可可西里—东昆仑活动构造带分段破裂 ,强震的破裂长度和震级之间大致满足对数线性的统计关系 ,强震活动呈现指数型时间分布的加速特征。这种强震加速活动特征可以用含多个震源体的孕震系统的强震成组活动模型给予解释。 相似文献
2.
介绍了中国及邻区地震目录数据库的开发状况，从历史强震、近代强震及强震震源深度等几个方面，结合我国及邻区板块构造以及应力状态、壳幔结构的东西部差异对我国强震的空间格局进行了较为系统的分析．公元1900年以前我国华北地区的强震呈现出大梯形格局，而公元1900年之后我国强震则以西部的巨大扇形为主要特征，其中震源深度最深的区域分别位于大扇形的2个顶点处，即兴都库什-帕米尔以及缅印交界地区．就我国强震所特有的空间分布格局对我国强震的线性以及区域性迁移模式进行了总结和分析，其中线性迁移模式又可细分为前进跳跃式和钟摆式．对文中涉及的强震迁移机制分别利用断层破裂、弹簧-滑块、壳幔的结构性差异以及它们之间的相对运动等模型进行了初步的解释． 相似文献
3.
本文将20世纪全球强震活动划分为7个活动期,以国内中强以上地震同期活动资料进行比较,对未来国内强震活动趋势作出中期的统计概率预测,似乎可以作为一个较为有力的判据。 相似文献
4.
地壳表层构造和深部构造互相制约是控制河北地区许多强震发生的必要地质条件。由此地质条件,在水平与垂直两个相互叠加的应力场作用下,使河北地区发生许多强震。这个构造-应力场模式,对华北地区许多强震的发生可能具有普遍意义。 相似文献
5.
东昆仑活动断裂带是青藏高原内部一条长度达到1000km以上的活动断裂带。在近100年期间,沿该断裂带曾发生过4次M S7.0以上地震。最新一次强震是2001年昆仑山口M S8.1地震。本文综合前人资料,通过东昆仑活动断裂带的几何展布、活动速率、历史强震及古地震地表破裂带展布,讨论了该断裂带的强震破裂分段特征、强震破裂端点障碍体的稳定性,强调了从断裂带演化过程认识断裂带的几何展布与现今强震地表破裂分段的异同,并讨论了该断裂带未来的强震破裂危险地段。 相似文献
6.
“5·12”汶川特大地震过去一年了,然而关于地震的争议远没有停止。中国是否进入强震频发期？地震预报为什么这么难？水库是否诱发了地震……地震带来的一系列问题让地质专家不断研究和思索。1争论一：中国乃至全球是否进入强震频发期 有学者认为,2004年12月26日印尼苏门答腊发生的9级强震拉开了2004-2018的全球强震序幕。 相似文献
7.
对强震发生后周围断层及未来强震形势的影响研究具有非常重要的意义.青藏高原东北缘强震频发,对该区的历史强震进行研究很有必要.以青藏高原东北缘及邻区为目标建立3D黏弹性有限元模型,依据中国大陆Ⅰ级块体和青藏高原Ⅱ级块体划分及活动断裂分布确定模型块体边界及断裂位置,使用GPS观测资料作为模型边界条件,数值模拟1900年以来7级以上强震发生的动力学过程.计算结果表明:① 青藏高原东北缘及邻区区域水平构造应力场特征大致呈从西向东,从南向北减小分布.② 模拟结果说明强震主要发生在背景场应力和强震引起的等效应力加载的断层上.③ 历史强震序列对1970年以来地震的影响:康定地震加速触发了炉霍地震的发生;康定、炉霍地震对松潘地震无加速触发作用;康定、炉霍、松潘地震对共和地震无加速触发作用;炉霍、松潘、共和地震对汶川地震的影响较小;汶川地震延缓了芦山地震的发生. 相似文献
8.
中国大陆１９９２－１９９３年强震中期预测和检验胡连英（江苏省地震局，南京，１０００１４）关键词：强震，中期预测，断裂带，地震活动，中国大陆。ＭｅｄｉｕｍＴｅｒｍＰｒｅｄｉｃｔｉｏｎａｎｄＩｎｓｐｅｃｔｉｏｎｏｆＳｔｒｏｎｇＥａｒｔｈｑｕａｋｅｓｉｎ１... 相似文献
9.
通过对汰内井水氡多年年变动态的分析,发现台湾地区强震前后汰内井水氡测值表现出持续高值的异常,这些异常多为中期与中短期异常,有时也有短临异常和震后效应。研究结果表明,汰内井水氡对台湾地区的强震有一定的映震能力,可为台湾地区的强震预测服务。 相似文献
10.
本文介绍十五期间福建省将要实施建设的数字强震观测台网 ,着重从项目的必要性和方案的可行性方面进行论述 ,同时结合福建省的地震监测台网现状进行系统的设计。力求建成的强震观测系统能初步实现福建省属重点城市的地震烈度速报及典型场地强地震动记录获取双重功能 ,增强福建省的地震监测能力 ,为福建省地震灾害的减轻、有效救灾措施的实施以及防震减灾规划的制定提供基础依据 ;同时 ,也将为其他省市区域数字强震观测台网的建立提供示范样板 相似文献
11.
~~强震观测实时处理技术及其应用前景@金星$福建省地震局!局长,研究员,博士生导师~~ 相似文献
12.
The October 6/2000 Tottori earthquake that occurred in central Japan was an intermediate size strike-slip event that produced a very large number of near field strong motion recordings. The large amount of recorded data provides a unique opportunity for investigating a source asperity model of the Tottori earthquake that, combined with a hybrid strong motion simulation technique, is able to reproduce the observed broadband frequency near-fault ground motion. We investigated the optimum source asperity parameters of the Tottori earthquake, by applying a Genetic Algorithm (GA) inversion scheme to optimise the fitting between simulated and observed response spectra and Peak Ground Acceleration (PGA) values. We constrained the initial model of our inversion by using the heterogeneous slip distribution obtained from a kinematic inversion of the source of previous studies. We used all the observed near-fault ground motions (−100 m) from the borehole strong motion network of Japan (KiK-Net), which are little affected by surficial geology (site effects). The calculation of broadband frequency strong ground motion (0.1–10 Hz) is achieved by applying a hybrid technique that combines a deterministic simulation of the wave propagation for the low frequencies and a semi-stochastic modelling approach for the high frequencies. For the simulation of the high frequencies, we introduce a frequency-dependent radiation pattern model that efficiently removes the dependence of the pattern coefficient on the azimuth and take-off angle as the frequency increases. The good agreement between the observed and simulated broadband ground motions shows that our inversion procedure is successful in estimating the optimum asperity parameters of the Tottori earthquake and provides a good test for the strong ground motion simulation technique. The ratio of background stress drop to average asperity stress drop from our inversion is nearly 50%, in agreement with the theoretical asperity model of Das and Kostrov [Das, S., Kostrov, B.V., 1986. Fracture of a single asperity on a finite fault: a model for weak earthquakes? Earthquake Source Mechanics, AGU, pp. 91–96.], and an empirical ratio of asperities to rupture area [Seismol. Res. Lett. 70 (1999) 59–80.]. The simulated radiation pattern is very complex for epicentral distances within half the fault length, but it approaches the radiation of a double-couple point source for larger distances. The rupture velocity and rise time have a significant influence on the Peak Ground Velocity (PGV) distribution around the fault. An increase in rupture velocity produces a similar effect on the ground motion as a reduction in rise time. 相似文献
13.
The suitability of a very fast method for obtaining synthesizing accelerograms has been demonstrated for a hybrid simulation technique of source wavelet and acceleration envelope waveform for the 2002 Avaj earthquake. This method is based on the amplitude modeled white noise and envelope waveform. The estimation of peak acceleration from a preliminary simulated record is based on using modeling parameters of rupture plane instead of empirical relations for peak acceleration. Based on comparison between observed and simulated strong ground motion data, a fair agreement is observed between simulated and observed records up to distances 40 km for peak acceleration and duration. The most important feature of the recorded strong motion is decay up to a distance of 40 km which is due to direct upgoing shear waves. At distance of 50 to 60 km peak acceleration increase, which is due to postcritical reflection from velocity gradient in the lower crust. A flat trend is observed for peak acceleration at distance of 60 to 100 km. The simulation indicates that the rupture is started at depth of 8 km and propagated from northwest to southeast. The causative fault for the 2002 Avaj earthquake shows similar mechanism to the 1962 Buin-Zahra earthquake. 相似文献
14.
台湾地处中国大陆东南边缘是菲律宾海板块凸向亚欧大陆俯冲-碰撞异常岛弧带。福建位于台湾岛弧西侧活动地块。闽台独特的构造格架、地球动力学状态和构造应力场与地震活动之间的内在关联性,使之成为研究海陆板块俯冲-碰撞效应及其对板内地震活动影响天然地区。本文主要依据近30多年以来对福建地块的地震地质背景、地壳变形观测、构造应力场、地震活动性以及地壳-上地幔结构探测、地热场等资料,结合台湾学者详细对台湾岛弧地球动力学与强震构造等研究成果,探索海陆板块俯冲-碰撞地球动力学特征及其对板内活动地块影响,进而揭示板间-板缘-板内强震活动关联性和动力学性状的异同性。试图为本区强震预测和防震减灾对策提供新思路。 相似文献
15.
The strong motion displacement records available during an earthquake can be treated as the response of the earth as the a
structural system to unknown forces acting at unknown locations. Thus, if the part of the earth participating in ground motion
is modelled as a known finite elastic medium, one can attempt to model the source location and forces generated during an
earthquake as an inverse problem in structural dynamics. Based on this analogy, a simple model for the basic earthquake source
is proposed. The unknown source is assumed to be a sequence of impulses acting at locations yet to be found. These unknown
impulses and their locations are found using the normal mode expansion along with a minimization of mean square error. The
medium is assumed to be finite, elastic, homogeneous, layered and horizontal with a specific set of boundary conditions. Detailed
results are obtained for Uttarkashi earthquake. The impulse locations exhibit a linear structure closely associated with the
causative fault. The results obtained are shown to be in good agreement with reported values. The proposed engineering model
is then used to simulate the acceleration time histories at a few recording stations. The earthquake source in terms of a
sequence of impulses acting at different locations is applied on a 2D finite elastic medium and acceleration time histories
are found using finite element methods. The synthetic accelerations obtained are in close match with the recorded accelerations. 相似文献
16.
本文简要介绍福建漳州某地填土地基强夯试验监测项目,利用钻探、原位测试及孔隙水压力、水平位移、螺旋沉降、磁性分层沉降、水位及沉降标观测等试验监测手段,对强夯加固填土地基试验进行监测研究,并对强夯效果作出评价。 相似文献
17.
针对强震能否预测以及如何预测的科学难题,建立孕震断层多锁固段脆性破裂理论,发现强震孕育过程的指数规律：sf（k）=1.48ksc,其中sf（k）和sc分别为第k个锁固体断裂点与第一个锁固段膨胀起点对应的累加Be-nioff应变,可以利用锁固段在其变形膨胀点处开始发生的震群事件（加速性地震活动前兆）预测未来大震,并给出了强震四要素相关预测方法。通过对诸多历史强震（如邢台地震、海城地震、汶川地震、玉树地震等）的回溯性检验分析表明：强震可以预测,且其孕震过程都遵循着上述简单的共性力学规律。在此基础上,归纳出4种典型强震的孕震模式,即大震震级呈＂大—小—大＂型,大震震级呈连续上升型,锁固段快速连续破裂型与标准型。此外,根据相关强震预测理论方法,对有关抗震救灾未来研究的方向提出如下建议：建议加强活动断裂位置精确定位、性质判定的地震地质研究,并开展孕震区锁固段（闭锁区域）判识的地质与地球物理研究等。 相似文献
18.
Summary The high amplification of the 1985 Mexico City earthquake is explained by the large number of strong and nearly continuous cycles of 2 s period motion lasting for more than 30 s. The type of damage caused by the earthquake—particularly to engineered multi-storey buildings of high flexibility is described, and methods of adding damping and stiffness elements to reduce and resist earthquake demand forces are discussed. 相似文献
19.
本文概述了南北地震带南段的水文地质条件和水文地球化学特征,并编绘了B、F、Li、Sr等微量元素的异常图,分析了水文地球化学与地震的关系。认为(1)构造对地震、地下热水和微量元素的高值区均具有控制作用,它们在空间分布上具有较明显的一致性;(2)高中温热水区(尤其是高中温热泉密集带),常常是地震活动的强烈区,但强震区不一定有高中温热泉密集;(3)在地震孕育过程中,温泉和热水井中的水温、流量和水化学成分均可发生变化。温泉热水中的水化学成分,特别是微量元素变化是地震预报的前兆信息之一。 相似文献
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