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1.
采用中小地震的数字观测资料，依据地震观测谱和震源谱、传播路径衰减因子及场地效应的关系式，在对场地效应约束的条件下，反演S波非弹性衰减和软基岩场地效应，确定研究区路径、 场地参数. 该方法确定的参数， 避免了台站地形效应的影响，真实地反映了研究区自由软基岩场地的地震效应和传播路径非弹性衰减的影响. 研究区的平均软基岩场地效应， 在2~4 Hz频率范围为1.5倍左右; S波品质因子为QS=278 f 0.346.这些参数可以直接用于研究区的地面运动随机模拟. 相似文献
2.
用随机模拟方法研究设定地震地面运动可分两步进行：（1）采用中小地震的数字观测资料确定研究区路径、场地参数；（2）把确定的参数应用到研究区的强地面运动随机模拟中. 为此，本文首先采用了一种可行的方法，分离软基岩场地效应和非弹性衰减的影响，并把二者分别确定出来. 研究区北部中软基岩场地的平均效应在2～4Hz频率范围为15倍左右；研究区的S波品质因子为QS＝278f[KG*2]0.346. 把这些参数用于研究区的场地和路径模型中，并选择单拐角频率震源谱模型，随机模拟了研究区未来中强地震可能在北天山中段可能造成的地面运动，模拟加速度时程和反应谱可以服务于本地区的地震灾害预测和建筑物可靠性验算. 相似文献
3.
Introduction Seismic recording is the information recorded by seismograph when earthquake occurs, which is a kind of comprehensive information, including the characteristics of earthquake focus, propagation path of seismic wave and site response, etc. Therefore, we must try to distinguish source effect, propagation path and site response in the seismic recordings in order to obtain accu-rate parameters. The method of Atkinson has better solved the problem (Atkinson, Mereu, 1992), which is bas… 相似文献
4.
根据山西数字地震台网14个地震台的310条波形资料，研究了山西地区的非弹性衰减系数；采用Atkinson和Moya方法，研究了各台的场地响应和几种震源参数，并对这两种方法的反演结果进行了对比分析. 得到山西地区非弹性衰减Q值随频率f的关系为Q(f)=323.2f 0.506；得到的14个台站的场地响应均没有显示出明显的放大效应，这与山西台站均处于岩石地基相符；得到了拐角频率与地震矩、地震矩与应力降、震源半径与应力降之间存在依赖关系. 相似文献
5.
甘肃地区S波非弹性衰减Q值研究 总被引：3，自引：0，他引：3
文中利用新建"十五"数字化地震观测网络项目记录到的甘肃地区地震波形资料,研究了甘肃地区S波的非弹性衰减Q值,得到甘肃东南地区Q值与频率的关系为Q(f)=374.0f0.3084;祁连山中东段地区Q值与频率的关系为Q(f)=693.6f0.2865。从分区Q值研究结果看,各分区之间存在较大差异,显示出了Q值空间分布的非均匀性特征,这种区域差异性与甘肃地区构造活动、地震活动、地壳速度结构及热活动状态的区域差异性有较好的一致性,活动强烈、高热活动以及低速区为相对低Q值区,地震波衰减较快。 相似文献
6.
胶东地区地壳S波衰减系数和台站场地响应的研究 总被引：1，自引：1，他引：0
根据山东数字地震台网7个地震台的118条波形资料,采用Atkinson方法（1992）,研究了胶东地区的非弹性衰减系数;采用Moya方法（2000）,研究了各台的场地响应。得到胶东地区非弹性衰减Q值随频率,的关系为Q（f）=249×f^0.596;得到的7个台站的场地响应均没有显示出明显的放大效应,这与胶东地区台站均处于岩石地基相符。 相似文献
7.
8.
用随机模拟方法研究设定地震的地面运动参数 总被引：1，自引：0，他引：1
本文从强地面运动随机模拟方法应用出发,提出了一种用中小地震的数字观测资料确定研究区路径、场地参数的方法。采用该方法,分离软基岩场地联合效应和非弹性衰减的影响,并把二者分别确定出来。这些参数可以直接用于研究区软基岩场地的地面运动随机模拟。 相似文献
9.
The available models for eff ective periods of site and structure are reviewed in context of frequency tuning in the inelastic seismic response of soil-structure system. The eff ect of seismic intensity and ductility demand, on the eff ective periods, is investigated, and inelastic site amplifi cation is shown to be strongly correlated to the normalized eff ective period. Two non-dimensional parameters, analogous to the conventional site amplifi cation factors in codes, are defi ned to quantify the inelastic site amplifi cation. It is shown that the inelastic site amplifi cation factor (i.e. ratio of constant ductility spectral ordinates at soil site to those at rock outcrop) is able to represent the site eff ects more clearly, as compared to the inelastic site amplifi cation ratio (i.e. ratio of inelastic spectral ordinates at soil site to the corresponding elastic spectral ordinates at rock outcrop). Further, the peak in the amplifi cation factor corresponding to the eff ective site period diminishes rapidly with increasing ductility demand. 相似文献
10.
采用分布于鄂尔多斯地块及其周缘的32个地震台站记录到的19次地震事件共487条数字化波形记录, 利用遗传算法反演得到了整个鄂尔多斯地块地壳内S波的三段几何扩散参数、S波非弹性衰减Q值随频率变化的关系式、32个台站的场地响应以及19次地震的震源参数. 计算结果表明, 鄂尔多斯地块地壳内S波非弹性衰减在1 Hz处的Q值比地质构造活跃地区的结果要大得多. 32个地震台站的场地响应在高频部分除个别台站外基本没有表现出明显的放大效应,但在低频区间部分台站之间有一定的差异. 19次地震事件的地震矩对数值与震级ML有很好的线性关系. 相似文献
11.
弹塑性地震反应谱的长周期特性研究 总被引：3，自引：1，他引：3
在基于性能抗震设计中弹塑性反应谱在计算结构地震位移反应方面越来越受到重视。利用统计分析方法研究了等强度的延性需求谱和等延性的强度折减系数谱的长周期(至5 s)区段的特性,关注的重点是等位移准则和场地条件影响。给出了若干具有工程价值的结论:一是周期介于1.5Tg(地震动特征周期)和2.5 s之间的结构可近似认为等位移准则成立且与场地条件关系不大,这样确定的强度折减系数当位移延性系数小于等于4时结果将是偏于安全的;二是结构周期大于2.5 s后以硬土场地等延性强度折减系数谱或等强度延性需求谱代替软土场地谱求解系统强度需求或延性需求,将会得到偏于安全的结果。 相似文献
12.
The study of seismic attenuation property is a major subject in seismology. Seismic waves recorded by seismic stations （seismographs） contain source effect, seismic wave propagation effect, site response of seismic stations and instrumental response. The path effect of seismic wave propagation, site response of seismic stations and instrumental response must be taken out in the study of source property with seismic data. The path effect of seismic wave propagation （seismic attenuation） involves an important influential factor, the anelastic attenuation of medium, which is measured with quality factor Q, apart from geometric attenuation with the distance. As a basic physical parameter of the Earth medium, Q value is essential for quantitative study of earthquakes and source property （e.g. determination of source parameters）, which is widely used in earthquake source physics and engineering seismology. 相似文献
13.
Introduction Located between Qingzang (Qinghai-Xizang) Plateau that highly uplifts due to compression and North China plain that badly subsides due to crustal extension, the Ordos massif has both the basic attributes of stretching tectonic region of North China marginal basin and the features of marginal shear-compression zone of Qingzang Plateau. It has a length of about 600 km in the N-S direction and a width of about 400 km in the W-E direction. Its geological structure is very simple… 相似文献
14.
Seismic wave propagation in viscoelastic and saturated rock 总被引：1，自引：0，他引：1
Considering engineering practice, the viscoelastic two-phase model is adopted, seismic wave propagation in saturated rock
is studied. Not only the effect of the viscosity of rock skeleton but also the effect of ground water on the propagation of
the seismic wave can be considered by this model, the propagation characteristics of seismic wave in saturated rock can be
understood comprehensively and the model is more reasonable than other model by which seismic wave propagation is studied.
The effect of frequency, water content and viscosity constant on the wave velocity and attenuation are studied by numerical
examples and some valuable conclusions are drawn. 相似文献
15.
山东地区地震动衰减和场地响应的研究 总被引：3，自引：0，他引：3
采用Atkirlsorl方法,基于遗传算法反演山东地区非弹性衰减Q值,在此基础上利用Moya等方法进行了台站的场地响应的测算。数据分析使用的是山东数字地震台网最早正式运行的8个数字台站记录的所有地震,采用信噪比方法挑选出质量较高的16次地震,对记录谱进行路径校正后参与计算得到每个台站的场地响应值。研究结果表明：在所研究的频率范围内非弹性衰减Q值和频率f有很好的线性关系,Q（f）9=297．4f^0.558;8个数字地震台中的7个基岩台均没显示出明显的放大作用。1个井下摆台站场地响应在高频部分衰减很快。 相似文献
16.
核电厂标准化设计方法是节省核电建设成本的重要手段,开展非岩基厂址地基标准化设计地基模型的研究对拓宽核电厂地基适用范围有重要意义。首先,基于国内外典型软质岩和硬土厂址动参数的调研数据进行数理统计分析,归纳动参数随深度的变化规律,并通过归一化分析得到地基剪切波速剖面特征曲线,从而确定初步的标准化地基模型;进而,基于SuperFLUSH/2D Ver6.0软件开展初步标准地基模型的地震反应分析,以最大加速度随深度变化与加速度反应谱为考量指标探究动参数变化对于地震反应的影响程度及规律;最后,依据初步地基模型的剪切波速剖面的相似性及包络性,定义软质岩和硬土厂址条件下的核电厂标准化地基模型,并给出相应的动参数合理取值。该模型及研究成果可为我国“核电走出去”战略中主力堆型的核电厂标准化设计提供重要的参考。 相似文献
17.
根据地震构造环境和震害分布特点， 将四川及邻区划分为西南地区和四川盆地地区. 收集了西南地区96次、 四川盆地地区40次近代破坏性地震资料， 并对各次地震的震级参数进行了统一校核. 按照该地区震中烈度与震级、 有感半径与震级的统计关系， 对地震烈度衰减进行了近场与远场特征控制， 建立了地震烈度沿长轴、 短轴和平均轴的衰减关系. 统一了中国与美国面波震级的震级标度， 利用最新得出的美国西部基岩水平向地震加速度反应谱衰减关系， 采用考虑地震加速度的近场距离饱和与震级饱和特征的衰减模型， 转换得到了该地区的基岩水平向地震加速度反应谱衰减关系. 相似文献
18.
In a previous study published in this journal, the authors developed a comprehensive methodology for modelling the shear wave velocity profile in crustal rock, for purposes of seismic hazard assessment. The derived shear wave velocity profile was used to estimate the amplification and attenuation mechanisms in the transmission of seismic waves. The ability to conduct seismic hazard assessments in regions of low and moderate seismicity is greatly enhanced by this new modelling approach, given that developing a local attenuation model based on curve-fitting strong motion data is generally not feasible under such conditions. This paper reports a follow-up study conducted to evaluate the significance of near-surface attenuation in bedrock (as distinct from attenuation in unconsolidated soft soil sediments). The κ parameter is used to characterize the extent of this attenuation mechanism. Empirical correlations of κ with two forms of near-surface shear wave velocity parameter in crustal rock have been developed, employing information obtained from global sources in conjunction with that from local studies. The resulting development of two simple equations to predict median values of κ as functions of readily available shear wave velocity parameters represents the key outcome of this study. Applications of the proposed empirical approaches to determine κ have been provided, taking Hong Kong and Melbourne as case studies to illustrate different aspects of the proposed methodology. Consistency between the results obtained by the two recommended approaches has thereby been demonstrated. 相似文献
19.
This paper investigates the effects of random variations of soil properties on site amplification of seismic waves. First, based on attenuation laws and the filtered Tajimi–Kanai spectrum, seismic motion at the base rock of a soil site is stochastically generated according to an assumed earthquake with a given magnitude and epicentral distance. Motions on the surface of this layered random soil site are calculated by nonlinear wave propagation methods, and by assuming the incoming seismic wave consisting of SH wave or combined P and SV waves. Soil properties, including shear modulus, damping ratio and mass density, as well as ground water level are considered as random in the numerical calculation. The Rosenblueth method is used to solve the random dynamic responses of the soil site. Parametric calculations are performed to investigate the effects of various parameters on site amplification of seismic waves. The mean and maximum ground motions on surface of the site are estimated. Numerical results indicate that the estimated surface motions differ substantially if the random variations of soil properties and soil saturation level are taken into consideration in the analysis. 相似文献
20.
根据特定震源机制、震级、断层距和场地条件选取69条地震动记录并进行分组,利用Nspectra软件计算隔震结构的弹塑性位移反应谱,分析断层距、场地条件、震级、阻尼比对弹塑性位移谱的影响,探讨隔震层的力学参数对地震能量耗散的影响。研究结果表明:相较于远场,处于近场的隔震结构最为不利,隔震层位移谱值受场地条件、地震加速度和速度大小影响较大;随着断层距的增大,位移谱值衰减较快,且在软土场地中隔震层的位移谱值衰减幅度大于硬土场地;地震震级大小对位移谱形状的影响不明显,但能够使隔震层的位移谱值产生整体缩放效应;阻尼比在小于0.4的范围内,隔震层在不同地震动特性作用下位移谱值差别较大,但在大于0.4以后,位移谱值及谱形基本趋于一致;屈服力较小(恢复力/重力小于等于1)的隔震层随自振周期增大其耗能性能更加突出。 相似文献