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1.
Firstly, the impact of historical earthquakes on 34 China province-level capital cities is evaluated by using historical earthquake
catalog. The distribution of affected intensity shows, about 53% of cities have even not been affected by earthquake intensity
VI, and 44% of cities have been hit by earthquake intensity VII to IX. For most of the cities, occurrence frequency of affected
intensity VI is usually higher than that of affected intensity larger than VI, and the value of affected intensity with maximal
occurrence frequency may be very different among cities. So both the maximal affected intensity and the affected intensity
with maximal occurrence frequency should be taken into account when the prevention seismic intensity needs to be determined.
Secondly, considering the incompleteness of records of historical earthquakes, a method of earthquake catalog computer simulation
is introduced to study the features of affected intensity of big cities. 69 county-level cities of Fujian Province are selected
to be statistical objects. The statistical result shows, for different risk levels the seismic intensity changes greatly among
cities, the seismic intensity of 2% probability of exceedance in 50 years can be regarded as the characteristic affected intensity
of city, and can be the basis of determining the city special earthquake prevention level and a proper indicator of future
earthquake’s impact on cities.
Foundation item: A Public Benefit Foundation of the Ministry of Science and Technology of China. Contribution No. 04FE1005,
Institute of Geophysics, China Earthquake Administration. 相似文献
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The analysis of seismic hazards relies on the statistical analysis of historical seismic data and the instrumental seismic catalog to obtain the regional earthquake recurrence interval and earthquake probability. The accuracy of analysis thus depends strongly on the completeness of the seismic data used. However, available seismic catalogs are too short or incomplete for the reliable analysis of the statistical characteristics of earthquakes. If a long-term synthetic seismic catalog can be generated using a physics-based numerical simulation, and the simulation results match the crustal deformation, seismicity, and other observations,then such a synthetic catalog helps us to further understand the characteristics of seismic activity and analyze the regional seismic hazard. In this paper, taking the northeastern Tibetan Plateau as a case study, we establish a three-dimensional visco-elastoplastic finite-element model to simulate earthquake cycles and the spatiotemporal evolution of earthquakes on the model fault system and obtain a seismic catalog on a time scale of tens of thousands of years. On the basis that the model satisfies the regional geodynamics of the northeastern Tibetan Plateau, we analyze seismicity on the northeastern Tibetan Plateau using the simulated synthetic earthquake catalog. The characteristics of earthquake recurrence at different locations and different magnitudes, and the long-term average probability of earthquake occurrence within the fault system on the northeastern Tibetan plateau are studied. The results are a reference for regional seismic hazard assessment and provide a basis for the physics-based numerical prediction of earthquakes. 相似文献
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利用华北地区地震活动性资料,建立了地震危险性计算的一致性模型.在此模型的基础上,得出了北京、天津、唐山和济南等7个城市未来2500年内地震的时空强度分布,并计算了2500年回复周期的地震动峰值加速度(PGA).结果表明,唐山和太原的PGA最大(>0.2g),石家庄和北京次之(≈0.17g).对华北地区2500年地震记录的正演计算结果表明,太原和唐山地区的潜在地震危险最有可能来源于震级在6.0～7.0、震中距离在12～15km的地震活动;而北京、天津和石家庄地区则可能来源于震级在5.5～6.0、震中距离在10km左右的地震活动.采用IBC(International Building Code)方法计算后的结果显示,太原、唐山等地区的PGA与2001年我国地震动峰值加速度值基本一致,与此地区的较高地震活动性特征相符.利用随机震源模型,还给出了影响此7个城市的最大地震记录的加速度、速度及位移时程曲线,这对本区工程建筑的抗震性设计以及对救援设施的选址等有重要作用. 相似文献
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从历史最大地震烈度分布图分析,可知揭阳、汕头、潮州三市位于Ⅶ～Ⅷ度高地震烈度区。该城市群地震灾害有以下特点:市区发生破坏性地震的潜在危险性大;地震时市区地震烈度高,地震灾害大,损失严重。采用宏观经济易损性的地震损失分析方法,重演该区的历史破坏性地震。分析表明:抓好该区的防震减灾工作是保持社会和经济建设持续发展的一项重要工作。 相似文献
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根据2022年云南宁蒗MS 5.5地震现场调查情况,详细描述本次地震的烈度分布情况和房屋震害特征,计算各烈度区内各类房屋结构的平均震害指数和破坏比,与2012年宁蒗—盐源MS 5.7地震和历史地震震害统计规律进行对比,结果表明： ①本次地震最大烈度为Ⅶ度,长轴呈NW向,与地震构造背景、震源机制解、余震序列分布和震例统计规律等科技支撑成果吻合较好; ②本次地震中房屋震害较轻,主要得益于脱贫攻坚、农村危房改造和抗震改造等项目的实施,震区房屋结构的整体抗震性能加强。 相似文献
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利用１９７０～１９９４年华北地区仪器记录到的地震目录，通过层次模型，将该地区分为不同大小的单元，在每个单元中，由小震活动情况，通过Ｇ－Ｒ关系是到较大地震的活动情况；并根据震级和烈度之间的关系，得到未来５０ａ不同地震烈度的发生概率，文中还将所得结果与历史地震活动情况以及第三代区划图进行对比研究，结果表明，由近代小震活动对地震危险性进行评估是可能的。 相似文献
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我国是地震多发的国家之一,其中破坏性地震的发生频率也相对较高。伴随着我国经济的高速发展与城市化进程的加快,地震风险意识的提高以及国家对地震应急救援能力的更高要求都促进了对地震灾害评估方法的研究。其中地震人员伤亡评估方法更是灾情预测的重中之重,然而我国大部分历史地震都发生在西部,已有的地震人员伤亡评估方法也是基于西部历史地震资料统计分析得出的。人口密度更高和经济更为发达的东部地区,一旦遭遇破坏性地震,其灾害程度将远超西部,因此现有方法已不能很好地满足东部地区的地震预防和应急救援决策需求。需要结合东部地区的特点修正适用于东部地区的地震人员伤亡评估方法。本文初步分析了东西部影响地震人员伤亡的影响因素,对比主要区域差异,指出东西部地区建筑的抗震性能差异主要体现在城市自建房屋的比例和农村主要结构类型占比上。给出了东部地区地震人员伤亡评估的修正系数,并通过算例分析了其适用性。 相似文献
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设定地震及其烈度影响判别 总被引：1，自引：0，他引：1
设定地震常用于震害预测、地震小区划和重大工程选址,烈度衰减模型反映了地震引起的地面震动及其影响的强弱程度分布。设定地震包括确定性和非确定性设定两种方法,确定性方法基于构造或历史地震,非确定性方法是基于概率危险性方法,用于估计区域或城市未来可能遭遇的地震危险。缺失等震线或震害记载不详的历史地震和概率设定地震都不能确切地反映地震破坏影响,借助于烈度衰减关系模型和GIS,可直观地判别其影响分布情况,便于设定地震的取舍。 相似文献
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地震目录资料是进行地震预测、地震危险性分析、地震活动性研究等地震学研究的基础资料.对地震目录资料的完整性可靠性分析是地震学研究的基础工作之一.近几十年来我国积累的大量的仪器地震记录,历史地震也在不断更新,为地震活动性研究提供了更为丰富的样本,因此有必要对新的地震目录进行完整性分析.本文采用了新的统计方法对我国仪器记录地震目录和历史破坏性地震目录进行了完整性分析.结果表明,对于仪器记录地震目录（M≥3.0）我国东部地区1975年后基本完整,西部地区1980年后基本完整.对于历史地震目录（M≥5.0）,东部地区1500年后基本完整,西部地区1950年后基本完整.考虑到华北地震区历史破坏性地震（M≥43/4）活动的时间非平稳性,我们采用突变点分析法研究了华北地震区历史破坏性地震目录的时间特征,得到了华北地震区地震活动周期性变化的突变点位置,并揭示了华北地震区历史破坏性地震目录完整起始时间约为公元1500年前后. 相似文献
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川滇菱形块体及其边界断裂带(21°～33°N,96°～108°E)是中国大陆地震活动最强烈的地区之一,该地区发生的一系列大地震造成了巨大的人员伤亡和财产损失。文中分别应用基于地震空间相关性和地壳形变场的预测方法分析了该地区未来的地震危险性。由Kagan等(1994)提出的基于地震空间相关性的方法,假定未来发生地震的概率与历史发生地震的频度成正比,根据历史地震目录建立统计学模型估计未来发生地震的概率。回溯性检验表明,这种方法对于评估地震复发周期较短的断裂带的地震危险性有较高的有效性,但对于地震复发周期较长的断裂带,如龙门山断裂带,很难给出一个理想的预期。由Shen等(2007)提出的基于地壳形变场的方法,假定长期地震危险性与地壳构造应变率成正比,根据由GPS观测获得的应变率场建立统计学模型评估未来的地震危险性。回溯性检验表明,川滇地区过去30a间发生的地震与区域应变率的大小没有明显的对应关系,但过去500a间发生的地震与应变率场有很高的相关性,表明由10a时间尺度的大地测量资料得到的地壳应变场可以很好地反映数百a时间尺度的地震危险性。 相似文献
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人工地震目录模拟是改进现有地震目录不完备性、弥补大地震记录稀缺,以及完善地震学相关研究的有效途径之一。本文基于地震活动的泊松分布模型、古登堡-里克特震级-频度关系,利用能较逼真描述具有随机性质事物特点及物理实验过程的蒙特卡洛方法,模拟汾渭地震带未来30、50、100年等不同时长的地震目录,并对其进行统计检验。分析表明,模拟地震目录符合设定的地震活动性参数和泊松分布假设特征。依据模拟地震目录,对未来该区域地震趋势进行了分析,以期为地震危险性分析提供参考。 相似文献
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The occurrence of the Algiers earthquake (M 6.8) of May 21, 2003, has motivated the necessity to reassess the probabilistic seismic hazard of northern Algeria. The fact that this destructive earthquake took place in an area where there was no evidence of previous significant earthquakes, neither instrumental nor historical, strongly encourages us to review the seismic hazard map of this region. Recently, the probabilistic seismic hazard of northern Algeria was computed using the spatially smoothed seismicity methodology. The catalog used in the previous computation was updated for this review, and not only includes information until June 2003, but also considers a recent re-evaluation of several historical earthquakes. In this paper, the same methodology and seismicity models are utilized in an effort to compare this methodology against an improved and updated seismic catalog. The largest mean peak ground acceleration (PGA) values are obtained in northernmost Algeria, specifically in the central area of the Tell Atlas. These values are of the order of 0.48 g for a return period of 475 years. In the City of Algiers, the capital of Algeria, and approximately 50 km from the reported epicenter of this latest destructive earthquake, a new mean PGA value of 0.23 g is obtained for the same return period. This value is 0.07 g greater than that obtained in the previous computation. In general, we receive greater seismic hazard results in the surrounding area of Algiers, especially to the southwest. The main reason is not this recent earthquake by itself, but the significant increase in the mmax magnitude in the seismic source where the city and the epicenter are included. 相似文献
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Oriented collapse of columns, large-scale destruction debris and temporary abandonment of the area deduced from an archaeological excavation provide evidence for a major (intensity IX) earthquake in Patras, Greece. This, and possibly a cluster of other earthquakes, can be derived from archaeological data. These earthquakes are not included in the historical seismicity catalogues, but can be used to put constraints to the seismic risk of this city. Patras was affected by a cluster of poorly documented earthquakes between 1714 and 1806. The city seems to be exposed to risks of progressive reactivation of a major strike-slip fault. A magnitude 6.4 earthquake in 2008 has been related to it. This fault has also been associated with a total of four events in the last 20 years, a situation reminiscent of the seismic hazard at the western edge of the North Anatolian Fault. 相似文献
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There was an earthquake swarm of two major events of MS6.3 and MS5.8 on the Xianshuihe fault in November, 2014. The two major earthquakes are both strike-slip events with aftershock zone along NW direction.We have analyzed the characteristics of this earthquake sequence. The b value and the h value show the significant variations in different periods before and after the MS5.8earthquake. Based on the data of historical earthquakes, we also illustrated the moderate-strong seismic activity on the Xianshuihe fault. The Kangding earthquake swarm manifests the seismic activity on Xianshuihe fault may be in the late seismic active period. The occurrence of the Kangding earthquake may be an adjustment of the strong earthquakes on the Xianshuihe fault. The Coulomb failure stress changes caused by the historical earthquakes were also given in this article. The results indicate that the earthquake swarm was encouraged by the historical earthquakes since1893, especially by the MS7.5 Kangding earthquake in1955. The Coulomb failure stress changes also shows the subsequent MS5.8 earthquake was triggered by the MS6.3earthquake. 相似文献
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首先利用 RISP系统对2022年6月10日0—12时四川马尔康地震序列的实时自动检测结果,并结合人工定位结果,对该时段系统自动检测结果进行详细对比分析.结果表明:系统自动检测的地震数量是人工正式目录的1．98倍,匹配率为93．2%,其中发震时刻偏差小于±1．0s的地震占比95．64%;震中位置偏差小于10km 的地震占比97．09%;震级偏差小于±0．3级的地震占比 96．36%.然后对系统多检测、漏检测和与人工目录地震参数偏差较大的地震进行详细分析,对系统检测密集地震序列的优缺点进行总结,并给出优化系统的建议.综合来看,RISP系统可快速产出高精度的震相到时数据和完备性较高的地震目录,可用于震后趋势判定、震源机制解节面判定、 余震快速精定位等地震应急工作. 相似文献
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合理地确定场地的历史地震影响烈度，是工程场地地震安全性评价工作中的重要一环。本文以广东南澳跨海大桥场址为例，论述了历史地震影响烈度分析的要点。首先对南澳附近１９１８年７．３级地震的震中位置及对桥址的影响烈度进行了确认；其次对选择合适的区域地震烈度衰减关系进行了分析比较，并建立了合理的桥址影响烈度目录；最后应用极值统计分析方法，得到不同平均重现期所对应的烈度值，为大桥的抗震设计提供了设防依据。 相似文献
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河北及邻区地震烈度衰减关系研究 总被引：1，自引：1，他引：0
杨凡 《地震地磁观测与研究》2017,38(2):98-103
地震震动的衰减关系在地震区划和工程场地的安全性评估过程中是不可或缺的。利用河北及周边区域历史地震的等震线资料,运用统计回归的分析方法,得到统计回归方程及地震烈度衰减关系,与其他烈度衰减关系进行对比分析,并与地震应急指挥技术系统软件及地震烈度分布资料进行对比,从而得到适用于河北及周边地区的地震烈度衰减关系。 相似文献
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对我国近海海域有历史记载以来的地震的震级、震中参数进行了整理分析,并分析了各海域地震活动的时、空分布规律,根据历史地震资料,确定海域受历史地震影响的最大影响烈度,然后初步分析了地震活动与现代构造应力场、地球物理场的关系.研究发现:(1)近海海域历史地震资料的精度较低,中强地震存在明显的遗漏.(2)渤海、台湾海峡、南海北部地震活动性较强,黄海次之,东海最弱.(3)近海海域的震害主要来自海域地震和近岸陆地强震的影响,影响强弱依次为:渤海、黄海、东南沿海、东海.(4)现代构造应力场以水平向构造应力场作用下的走滑运动为主,最大主应力方向受印度板决和太平洋板块、菲律宾海板块的俯冲挤压方向影响.(5)海域地球物理场,特别是布格重力异常、地壳厚度分布与强震构造带的空间分布关系的相关性较好.本文的研究结果可为我国海域及滨海重要工程的抗震设防、海域地震危险性区划提供一定的基础. 相似文献