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潜在震源区不确定性因素分析 总被引：5，自引：1，他引：5
本文根据洪华生(Der Kiureghian-Ang)断层破裂模型,对不同尺度的潜在震源区及各种震源参数进行了地震危险性数值计算。分析了潜在震源区划分范围,震级上限M_u及β值等地震活动性参数的不确定性对地震危险性分析的影响,其结果可供地震区划及工程地震等工作者参考。 相似文献
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为进一步揭示地震统计区划分、潜在震源区划分和地震活动性参数确定三者的关联性，在100deg;E～120deg;E和29deg;N～42deg;N范围内，寻找出21个位于不同位置、具有一定代表性的场点，研究在非均匀分布与均匀分布两种模型下，地震统计区活动性参数的不确定性对这些场点危险性估计的影响. 综合本次与以往的研究结果表明，不同的地震统计区划分方案会改变一个统计区所包含的地震资料，加上地震统计时段选取的不确定性，会导致统计区地震活动性参数估计的不确定性. 这种不确定性变化越大，均匀分布模型对场点危险性估计所产生的不确定影响也越大，也即地震统计区划分环节起主要作用. 在一个地震统计区内，划分潜在震源区和空间分布函数的不等权分配，提高了有可能发生大地震地方及其附近地区地震动参数的估计值. 在这些地方，潜在震源区划分不确定性的影响是很明显的，尤其对场点地震动参数（如烈度）绝对值的影响更为显著，也即潜在震源区划分环节起主要作用. 一般来说，潜在震源区划分环节的影响仅对最高和次高震级上限潜在震源区内的场点及最高震级上限潜在震源区附近的场点起主要作用，而对那些处于低震级上限潜在震源中的场点，则还是地震统计区划分不确定性的影响大于潜在震源区划分不确定性的影响. 相似文献
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潜在震源区震级上限不确定性研究 总被引：7，自引：1，他引：6
潜在震源区的震级上限（Mu）是指在该潜在震源区内可能发生的最大地震的震级．预期未来发生超过该震级地震的概率趋于0．本文运用误差分析及逻辑树等方法,并结合发震模型的数值模拟得到的大震合成目录等结果,系统分析并最终得到了不同途径给出的不同类型潜在震源区震级上限的不确定性．该结果可直接应用于包括地震区划在内的工程地震以及活动断裂危险性评价等工作中． 相似文献
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本文将潜在震源的不确定性分为震源类型与震源几何尺度的不确定性两类,用逻辑树方法概括了潜在震源区划分的各种可能方案,并据此给出了考虑潜在震源区划分不确定性的地震危险性分析的计算步骤。用本文的方法对上海市地震危险性进行了分析。 相似文献
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新地震区划图潜在震源区划分的主要技术特色 总被引：13，自引：7，他引：6
简要介绍了新地震区划图潜在震源区划分方案的形成过程,重点分析了潜在震源区三级划分、东西部地区潜在震源区划分技术途径的差异、不同级别活动块体边界带对高震级潜在震源区划分的控制作用、发震构造模型及其在潜在震源区划分中的应用等主要技术特色.共划分出29个地震带、77个地震构造区和1199个潜在震源区.与中国地震动参数区划图(2001)中综合方案相比,东西部地区潜在震源区的个数都有较大的增加,其中东部地区体现在震级上限6.0、6.5和7.0级的中强潜在震源区个数的明显增加,与划分工作中加强了该地区中强地震发震构造的判识研究相关;而西部地区体现在震级上限7.5和8.0级的高震级潜在震源区个数的大幅度增加,与划分工作中注重了活动块体边界带高震级潜在震源区划分,以及强调应用发震构造模型指导潜在震源区划分的技术特色相协调. 相似文献
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发震构造特性是潜在震源区划分及其地震年发生率确定的重要依据。潜在震源区除了反映“未来具有发生破坏性地震的地区”的内涵外,还应反映高震级档地震具有相似复发特征的涵义。由于在地震活动性参数统计单元内,有一些具有不同本底地震的活动构造块体,为更好地反映地震活动的空间不均匀性,考虑潜在震源区的三级划分是有必要的。通过分析潜在震源区内高震级档地震的复发特征,计算预测时段内潜在震源区的高震级档地震的发震概率,采用预测时段内概率等效转换获得地震年平均发生率的方法,有助于在中国地震危险性分析框架内考虑潜在震源区的强震复发特性。另外,文中还对潜在震源区内特征地震次级震级档频度不足的特性和发震构造上强震非均匀性在地震危险性分析中的应用问题进行了探讨 相似文献
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本文研究了俯冲带潜在震源区离散化方法及考虑俯冲带高震级地震震源破裂面和震源深度的场点地震动计算方法，推导了俯冲带潜在震源区地震危险性计算公式，并使用中国海域及邻区地震危险性模型进行地震危险性试算。结果表明，本文建立的考虑俯冲带潜在震源区的地震危险性算法能够实现场点地震危险性计算时对俯冲带高震级地震震源破裂面和震源深度的考虑。 相似文献
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潜在震源区的划分主要包括潜在震源区范围的划定以及震级上限的确定,目前遵循地震构造类比和地震活动重复等原则。而活断层的分段特性也是潜在震源区划分时必须考虑的一个重要因素。大青山山前断裂带至今有3种不同的分段方案,文中比较分析了前人对大青山山前断裂带的分段,并在此基础上对大青山及山前盆地的潜在震源区作了新的划分。鄂尔多斯块体周缘被拉张性断陷盆地围绕,这些断裂系地震构造相似,且除呼包盆地外均有历史8级以上地震记录。文中将大青山山前断裂带与鄂尔多斯块体周缘断裂系进行了构造对比,特别是与华山山前断裂进行了断裂活动性定量对比,得出雪海沟到土左旗段的震级上限为8级,断裂两端潜源震级上限均为7.5级 相似文献
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潜在震源区的判定是地震危险性分析工作的基础,潜在震源的准确性直接影响着地震危险性分析的结果的合理与否;本文采用多维实测数据类似性和差异性相对识别的ISODATA算法,对兰州——古浪地区的潜在震源进行了识别,给出了该地区的潜在震源区及其震级上限,为潜在震源区的综合判定提供了可靠的科学依据,使得潜在震源区的综合判定更为合理。 相似文献
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The seismic hazard of research area is evaluated by probabilistic analysis method for three different seismic statistical zone scenarios.The influence of uncertainty in seismic statistical zone delimiting on the evaluation result is discussed too.It can be seen that for those local sites along zone‘s border or within areas with vast change of upper bound magnitude among different scenarios the influence on seismic hazard result should not be neglected. 相似文献
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基于广义帕累托分布构建地震活动性模型,因其输入参数取值难以避免不确定性,导致依据该模型所得的地震危险性估计结果具有不确定性。鉴于此,本文选取青藏高原东北缘为研究区,提出了基于全域敏感性分析的地震危险性估计的不确定性分析流程和方法。首先,利用地震活动性广义帕累托模型,进行研究区地震危险性估计;然后,选取地震记录的起始时间和震级阈值作为地震活动性模型的输入参数,采用具有全域敏感性分析功能的E-FAST方法,对上述两个参数的不确定性以及两参数之间的相互作用对地震危险性估计不确定性的影响进行定量分析。结果表明:地震危险性估计结果（不同重现期的震级重现水平、震级上限及相应的置信区间）对两个输入参数中的震级阈值更为敏感;不同重现期的地震危险性估计结果对震级阈值的敏感程度不同;对不同的重现期而言,在影响地震危险性估计结果的不确定性上,两个输入参数之间存在非线性效应,且非线性效应程度不同。本文提出的不确定性分析流程和方法,可以推广应用于基于其它类型地震活动性模型的地震危险性估计不确定性分析。 相似文献
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Vladimir Yu Sokolov Friedemann Wenzel Rakesh Mohindra 《Soil Dynamics and Earthquake Engineering》2009
The earthquake risk on Romania is one of the highest in Europe, and seismic hazard for almost half of the territory of Romania is determined by the Vrancea seismic region, which is situated beneath the southern Carpathian Arc. The region is characterized by a high rate of occurrence of large earthquakes in a narrow focal volume at depth from 70 to 160 km. Besides the Vrancea area, several zones of shallow seismicity located within and outside the Romanian territory are considered as seismically dangerous. We present the results of probabilistic seismic hazard analysis, which implemented the “logic tree” approach, and which considered both the intermediate-depth and the shallow seismicity. Various available models of seismicity and ground-motion attenuation were used as the alternative variants. Seismic hazard in terms of macroseismic intensities, peak ground acceleration, and response spectra was evaluated for various return periods. Sensitivity study was performed to analyze the impact of variation of input parameters on the hazard results. The uncertainty on hazard estimates may be reduced by better understanding of parameters of the Vrancea source zone and the zones of crustal seismicity. Reduction of uncertainty associated with the ground-motion models is also very important issue for Romania. 相似文献
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Criteria for Selecting and Adjusting Ground-Motion Models for Specific Target Regions: Application to Central Europe and Rock Sites 总被引：6，自引：2，他引：6
Fabrice Cotton Frank Scherbaum Julian J. Bommer Hilmar Bungum 《Journal of Seismology》2006,10(2):137-156
A vital component of any seismic hazard analysis is a model for predicting the expected distribution of ground motions at a site due to possible earthquake scenarios. The limited nature of the datasets from which such models are derived gives rise to epistemic uncertainty in both the median estimates and the associated aleatory variability of these predictive equations. In order to capture this epistemic uncertainty in a seismic hazard analysis, more than one ground-motion prediction equation must be used, and the tool that is currently employed to combine multiple models is the logic tree. Candidate ground-motion models for a logic tree should be selected in order to obtain the smallest possible suite of equations that can capture the expected range of possible ground motions in the target region. This is achieved by starting from a comprehensive list of available equations and then applying criteria for rejecting those considered inappropriate in terms of quality, derivation or applicability. Once the final list of candidate models is established, adjustments must be applied to achieve parameter compatibility. Additional adjustments can also be applied to remove the effect of systematic differences between host and target regions. These procedures are applied to select and adjust ground-motion models for the analysis of seismic hazard at rock sites in West Central Europe. This region is chosen for illustrative purposes particularly because it highlights the issue of using ground-motion models derived from small magnitude earthquakes in the analysis of hazard due to much larger events. Some of the pitfalls of extrapolating ground-motion models from small to large magnitude earthquakes in low seismicity regions are discussed for the selected target region. 相似文献
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Potential sources are simplified as point sources or linear sources in current probabilistic seismic hazard analysis (PSHA) methods. Focus size of large earthquakes is considerable, and fault rupture attitudes may have great influ-ence upon the seismic hazard of a site which is near the source. Under this circumstance, it is unreasonable to use the simplified potential source models in the PSHA, so a potential rupture surface model is proposed in this paper. Adopting this model, we analyze the seismic hazard near the Chelungpu fault that generated the Chi-Chi (Jiji) earthquake with magnitude 7.6 and the following conclusions are reached. 1 This model is reasonable on the base of focal mechanism, especially for sites near potential earthquakes with large magnitude; 2 The attitudes of poten-tial rupture surfaces have great influence on the results of probabilistic seismic hazard analysis and seismic zoning. 相似文献
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Historical seismic data and seismogenic information are quite scarce for the low seismicity region, and modeling the parameters uncertainties based on probabilistic model is suspicious. The convex set theory-based seismic hazard analysis approach is proposed. The uncertainties of b value, the annual occurrence rate v and the upper bound magnitude Mu are described by the envelop bound convex model and the ellipsoidal bound convex model. Convex analysis method and China probabilistic seismic hazard analysis methodology are combined to perform a bound seismic hazard analysis for Ningbo city, China. The seismic intensity interval obtained using the bound seismic hazard analysis is compared with that calculated using China probabilistic seismic hazard analysis methodology. The sensitivity analysis indicates that the interval of seismic intensity is most sensitive to the annual occurrence rate v. Furthermore, the different convex models have little effect on the interval of seismic intensity. 相似文献