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龙门山北部陕甘川交界三角构造区断裂活动特征研究 总被引：2，自引：0，他引：2
龙门山北部3条不同走向的断裂带所围限的三角地区是我国陕甘川交界地区研究地震活动的重要场所.通过对区内秦岭南缘断裂、 平武—青川断裂、 岷江断裂及虎牙断裂活动特征研究和活动时代分析认为: 秦岭南缘断裂, 包括迭部—舟曲断裂、 武都—康县—略阳断裂及茶店—勉县断裂在晚更新世曾有过活动, 在全新世活动不明显; 龙门山断裂带东北段平武—青川断裂最后一次活动发生在晚更新世, 表现为右旋走滑的逆断裂, 全新世活动不明显; 岷江断裂和虎牙断裂不但在晚更新世活动强烈, 而且在全新世继续活动; 龙门山北部这个三角地区依然是未来地震活动关注的重点地区. 相似文献
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辽宁省主要活动断层与地震活动特征分析 总被引：6，自引：1，他引：5
本文结合编制 1：100 万辽宁省地震构造图,分析了辽宁省近 20 年来地震构造环境相关研究成果,确定辽宁地区共有第四纪以来活动断裂 29 条：全新世断裂 1 条;晚更新世断裂 5 条;早、中更新世断裂 23 条。其中北东向晚更新世活动断裂和北西向全新世活动断裂为辽宁地区的主要控震、发震构造。北东向晚更新世活动断裂与北西向断裂交汇部位、海城河隐伏断裂的端点部位和鸭绿江断裂南西端黄海海域是未来发生中强地震的主要部位。本研究可为深入研究辽宁地区地震构造条件、编制第五代全国地震区划图提供基础资料。 相似文献
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根据详细的野外调查和剖面测绘成果,结合区域第四系测年结果等资料,对龙蟠—乔后断裂带桃源段新发现的桃源断裂、刀郭断裂、合江村断裂及已知的龙蟠—乔后断裂等4条主要断裂的晚第四纪活动特征进行研究。成果表明,龙蟠—乔后断裂带桃源段在晚第四纪的活动特征明显,活动强度中等,龙蟠—乔后断裂和合江村断裂属全新世活动断裂,桃源断裂和刀郭断裂属晚更新世断裂;晚更新世以来,龙蟠—乔后断裂和刀郭断裂以左旋走滑运动为主,而桃源断裂和合江村断裂则表现为正断走滑为主。这些断裂的活动性都不同程度地影响着研究区及附近区域的地震风险和构造稳定性。新的调查研究成果为深入认识龙蟠—乔后断裂带桃源段的晚第四纪活动性提供了新的资料,并可为深入理解该区的地震地质特征以及工程建设地震安全性评价等提供基础地质资料。 相似文献
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《地球物理学进展》2016,(2)
空间分布函数将地震区、带的地震活动性参数按震级档分配到带内各潜在震源区,它的确定是综合概率地震危险性分析方法的关键性技术之一,其结果将直接影响所计算场点的地震危险性分析结果.然而,空间分布函数的确定由于地震样本的严重缺失难以统计得到,而实际工作中采用的评判因子太复杂、不独立等,使得到的空间分布函数缺乏可靠性.本文以渤海地震构造区为例,充分利用了该区近几十年来新建海洋石油平台工程获得的地质资料和历史疑难地震参数校核获得的地震活动资料,采用该区各潜在震源区面积、地震构造、地震活动度、中长期预报和强震复发间隔与构造空段五个因子,加权综合得到渤海地震构造区的空间分布函数,反映了该区地震活动的时空不均匀性,为概率危险性分析提供了计算参数.同时,本文运用综合概率地震危险性分析方法,由新的空间分布函数计算得到渤海地震构造区50年超越概率10%的海底泥面峰值加速度区划图,反映出研究区从0.05~0.20 g跨越五区,呈现西高东低的趋势,区域东部位于0.20 g(Ⅷ度区),西部位于0.05 g(Ⅵ度区)范围内,该区划结果可供该地区海洋石油平台等工程地震危险性分析研究时参考,对地震区划和工程地震安全性评价均有意义. 相似文献
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Hemchandra Chaulagain Hugo Rodrigues Enrico Spacone Ramesh Guragain Radhakrishna Mallik Humberto Varum 《地震工程与工程振动(英文版)》2014,13(3):455-470
Most current seismic design includes the nonlinear response of a structure through a response reduction factor(R). This allows the designer to use a linear elastic force-based approach while accounting for nonlinear behavior and deformation limits. In fact, the response reduction factor is used in modern seismic codes to scale down the elastic response of a structure. This study focuses on estimating the actual ‘R' value for engineered design/construction of reinforced concrete(RC) buildings in Kathmandu valley. The ductility and overstrength of representative RC buildings in Kathmandu are investigated. Nonlinear pushover analysis was performed on structural models in order to evaluate the seismic performance of buildings. Twelve representative engineered irregular buildings with a variety of characteristics located in the Kathmandu valley were selected and studied. Furthermore, the effects of overstrength on the ductility factor, beam column capacity ratio on the building ductility, and load path on the response reduction factor, are examined. Finally, the results are further analyzed and compared with different structural parameters of the buildings. 相似文献
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In current seismic design procedures, base shear is calculated by the elastic strength demand divided by the strength reduction factor. This factor is well known as the response modification factor, R, which accounts for ductility, overstrength, redundancy, and damping of a structural system. In this study, the R factor accounting for ductility is called the ‘ductility factor’, Rμ. The Rμ factor is defined as the ratio of elastic strength demand imposed on the SDOF system to inelastic strength demand for a given ductility ratio. The Rμ factor allows a system to behave inelastically within the target ductility ratio during the design level earthquake ground motion. The objective of this study is to determine the ductility factor considering different hysteretic models. It usually requires large computational efforts to determine the Rμ factor. In order to reduce the computational efforts, the Rμ factor is prepared as a functional form in this study. For this purpose, statistical studies are carried out using forty different earthquake ground motions recorded at a stiff soil site. The Rμ factor is assumed to be a function of the characteristic parameters of each hysteretic model, target ductility ratio and structural period. The effects of each hysteretic model to the Rμ factor are also discussed. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
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Jun Yang 《地震学报(英文版)》1998,11(4):455-465
The relation of tidal factor value to tiltmeter type has been founded from the harmonic analysis for observational data. The
relation is deducted theoretically. It is discovered that the frequency responses of different type tiltmeters and operative
periods or damping constant are slightly different in same station. The tiltmeter of small operative period is able to receive
more precursory information. That is the tidal factors obtained from harmonic analysis for observed data on tiltmeter of different
damping constant are different. The relation between frequency response and tidal factor is searched. It is necessary to calibrate
absolutely tiltmeter to predict earthquake. In order to obtain any amount of ground tilt information, it is necessary to select
appropriately different frequency tiltmeters to make comprehensive observation.
The study is sponsored by the Chinese Joint Seismological Science Foundation, No. 91100. 相似文献
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In modeling of overland flow and erosion, the overland flow friction factor (f), is a crucial factor. Due to the importance of a good understanding of f and its variability, the current study aimed to investigate the capability of non-linear approaches to estimate the Darcy-Weisbach friction factor of overland flow and its components (sediment transport, wave, form, and grain friction factors) through the Extreme Learning Machine (ELM) approach. Four datasets were used herein which were obtained from flume experiments done by different researchers. In order to investigate the effects of different parameters on the friction factor, numerous models consisting of various parameters were utilized to predict the friction factor using the ELM approach. The modeling procedure was established in two stages; the first stage aimed to model the overland flow friction factor and investigate the effect of the different parameters on the friction factor using non-linear separation via the ELM approach. In the second stage, the friction factor was linearly separated into different types of friction factors and then the separate components were estimated. Sensitivity analysis results confirmed the key role of Froude number (Fr) values for most of the models. On the other hand, the results obtained for estimated values of the friction factor were acceptable and outperformed available empirical approaches. 相似文献
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通过6种不同煤阶煤的弹性测试,分析了煤岩变质程度（以镜质组最大反射率表示）与煤岩品质因子之间的关系;在此基础上,进一步分析了煤岩速度与品质因子之间的关系及纵波与横波品质因子的各向异性特征.研究发现：煤岩镜质组最大反射率与纵波、横波品质因子均存在良好的线性相关性;垂直层理方向的波速与品质因子存在良好的线性关系,好于走向与倾向方向;垂直层理方向的纵波与横波品质因子线性相关,相关系数可达93.5%;煤岩的三方向品质因子存在各向异性,且强于速度的各向异性.通过横波品质因子与纵波品质因子间相互换算的理论公式计算结果与实验室实测结果的对比,证明了该理论公式的可靠性,误差小于10%,为多分量转换波的吸收衰减补偿提供了理论依据. 相似文献
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In this paper, on the basis of intensity data from 85 earthquakes occurred in China, the method of resolving overdetermined
equations by using the damped least squares method is applied to inversing for the mean value of 1 s. S wave quality factor,
the spreading factor and the S-wave acceleration at the foci of earthquakes in 7 regions of China. The relation between S-wave
acceleration at the foci of earthquakes and magnitude is discussed. As an example, 2-DQ
S distribution in Taiwan Province is obtained by inversion. It is found that there exists some corresponding relation between
this distribution and Bouguer gravitational anomaly and seismicity.
Preliminary analysis and discussion on results of the inversion, and estimation of error inQ
S are made.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 202–211, 1991.
The English version of this paper is improved by Professor Yushou Xie. 相似文献
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Prestack seismic inversion plays an important role in estimating elastic parameters that are sensitive to reservoirs and fluid underground. In this paper, a simultaneous inversion method named FMR‐AVA (Fluid Factor, Mu (Shear modulus), Rho (Density)‐Amplitude Variation with Angle) is proposed based on partial angle stack seismic gathers. This method can be used for direct inversion for the fluid factor, shear modulus and density of heterogeneous reservoirs. Firstly, an FMR approximation equation of a reflection coefficient is derived based on poroelasticity with P‐ and S‐wave moduli. Secondly, a stable simultaneous AVA inversion approach is presented in a Bayesian scheme. This approach has little dependence on initial models. Furthermore, it can be applied in heterogeneous reservoirs whose initial models for inversion are not easy to establish. Finally, a model test shows the superiority of this FMR‐AVA inversion method in stability and independence of initial models. We obtain a reasonable fluid factor, shear modulus and density even with smooth initial models and moderate Gaussian noise. A real data case example shows that the inverted fluid factor, shear modulus and density fit nicely with well log interpretation results, which verifies the effectiveness of the proposed method. 相似文献
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Application of caustic method to determining stress intensity factor of compressive shear crack 总被引：1，自引：0，他引：1
Introduction The caustics method has been introduced into seismology in recent years and preliminary in- vestigation indicates that it is effective to study the compressive stress (strain) of transparent sam- ples such as plexiglass (XU et al, 2001, 2002; Xu et al, 2000, 2002; XIONG et al, 2000, 2002). Especially, as a seismological concept, earthquake nuclei, becomes clearer according to the caustic shadow, which combines plastic area, nucleation area and crack concentration area together … 相似文献