潜在震源区内部空间非均匀分布地震区划方法在攀西地区和晋中南地区的应用   总被引：2，自引：1，他引：2  

高孟潭  胥广银 《中国地震》1996,(Z1)

本文依据潜在震源区内部地震非均匀分布模型研究了攀西地区和晋中南地区地震区划问题。研究结果表明，一般使用的均匀分布模型会低估地震危险性结果，导致高烈度分区的面积缩小。本文讨论了不同的确定非均匀分布概率的方法对地震区划结果的影响。  相似文献   

立交构造与渭河盆地地震活动   总被引：1，自引：0，他引：1       下载免费PDF全文

冯希杰  王平 《地震工程学报》2001,23(2):160-163

分析了鄂尔多斯地块南部和渭河盆地构造的空间分布特征，认为鄂尔多斯地块南部存在3条NW向隆起带，渭河盆地内部存在3个近EW向斜列的次级沉降中心，这些隆起带与次级沉降中心及其间的横向隆起共同组成了立交构造，分析了渭河盆地内部及其周边地区历史地震和现代地震的空间分布，发现立交构造对盆地内地震活动有着较强的控制作用。  相似文献   

Reliability analysis of drilled shaft behavior using finite difference method and <Emphasis Type="Italic">Monte Carlo</Emphasis> simulation     

Anil Misra  Lance A. Roberts  Steven M. Levorson 《Geotechnical and Geological Engineering》2007,25(1):65-77

Load displacement analysis of drilled shafts can be accomplished by utilizing the “t-z” method, which models soil resistance along the length and tip of the drilled shaft as a series of springs. For non-linear soil springs, the governing differential equation that describes the soil-structure interaction may be discretized into a set of algebraic equations based upon finite difference methods. This system of algebraic equations may be solved to determine the load–displacement behavior of the drilled shaft when subjected to compression or pullout. By combining the finite difference method with Monte Carlo simulation techniques, a probabilistic load–displacement analysis can be conducted. The probabilistic analysis is advantageous compared to standard factor of safety design because uncertainties with the shaft–soil interface and tip properties can be independently quantified. This paper presents a reliability analysis of drilled shaft behavior by combining the finite difference technique for analyzing non-linear load–displacement behavior with Monte Carlo simulation method. As a result we develop probabilistic relationships for drilled shaft design for both total stress (undrained) and effective stress (drained) parameters. The results are presented in the form of factor of safety or resistance factors suitable for serviceability design of drilled shafts.  相似文献   

Multiobjective analysis of chaotic dynamic systems with sparse learning machines     

Abedalrazq F. Khalil  Mac McKeeMariush Kemblowski  Tirusew AsefaLuis Bastidas 《Advances in water resources》2006

Sparse learning machines provide a viable framework for modeling chaotic time-series systems. A powerful state-space reconstruction methodology using both support vector machines (SVM) and relevance vector machines (RVM) within a multiobjective optimization framework is presented in this paper. The utility and practicality of the proposed approaches have been demonstrated on the time series of the Great Salt Lake (GSL) biweekly volumes from 1848 to 2004. A comparison of the two methods is made based on their predictive power and robustness. The reconstruction of the dynamics of the Great Salt Lake volume time series is attained using the most relevant feature subset of the training data. In this paper, efforts are also made to assess the uncertainty and robustness of the machines in learning and forecasting as a function of model structure, model parameters, and bootstrapping samples. The resulting model will normally have a structure, including parameterization, that suits the information content of the available data, and can be used to develop time series forecasts for multiple lead times ranging from two weeks to several months.  相似文献   

Testing earthquake prediction methods: «The West Pacific short-term forecast of earthquakes with magnitude MwHRV ≥ 5.8»     

V.G. Kossobokov   《Tectonophysics》2006,413(1-2):25

Analyzing the tables and probability maps posted by Yan Y. Kagan and David D. Jackson in April 2002–September 2004 at http://scec.ess.ucla.edu/~ykagan/predictions_index.html and the catalog of earthquakes for the same period, the conclusion is drawn that the underlying method could be used for prediction of aftershocks, while it does not outscore random guessing when main shocks are considered.  相似文献   

PNN网络在预测MCS移动中的应用   总被引：3，自引：0，他引：3  

苏君毅  过仲阳  邱洁  陆衍  吴健平 《上海国土资源》2004,14(3):27-30

神经网络是空间数据挖掘的一种重要手段。本文运用概率神经网络(PNN网络)对1998年夏季影响青藏高原上中尺度对流系统(MCS)东移的环境物理量场的空间分布特征进行了研究，得到了高原上MCS移动方向与环境物理量场空间分布之间的关系。研究表明，使用概率神经网络预测中尺度对流系统的移动具有较好的效果，从而为研究高原上MCS东移与环境场之间的关系提供了一种新的方法和思路。  相似文献   

概率神经网络与BP网络模型在遥感图像分类中的对比研究   总被引：6，自引：0，他引：6  

李朝锋  杨茂龙  许磊  杨蒙召 《国土资源遥感》2004,15(4):11-13,18

通过分析概率神经网络(以下称PNN)的基本结构及其训练算法,建立了卫星图像分类的概率神经网络模型,并通过实例对比分析了概率神经网络与BP网络分类模型的分类效果。实验表明,PNN图像分类方法在分类精度上优于误差反向传播神经网络模型,且分类时间相当,是一种有效的图像分类方法。  相似文献   

Hazard-consistent earthquake scenarios     

J. J. Bommer  S. G. Scott  S. K. Sarma 《Soil Dynamics and Earthquake Engineering》2000,19(4):691

Earthquake-resistant design and seismic analysis often require the earthquake action to be represented in the form of acceleration time-histories. Real accelerograms can be selected based on matching an earthquake scenario, defined by magnitude and distance, and scaled if necessary. The scaled accelerograms should reflect the hazard in terms of the parameters that characterise the inelastic demand on structures, including response spectral ordinates, duration and energy content. In order to maintain realistic ground motions, the scaling factors should not differ greatly from unity. It is found that in many cases, where the hazard is influenced by more than one seismic source, it is impossible to define a single earthquake scenario that is compatible with the results of probabilistic seismic hazard assessment. Even if a hazard-consistent scenario can be defined, there are difficulties encountered in using the results to select and scale real accelerograms.  相似文献   

Probabilistic versus deterministic seismic hazard analysis: an integrated approach for siting problems     

R. Romeo  A. Prestininzi 《Soil Dynamics and Earthquake Engineering》2000,20(1-4)

A methodology is proposed to determine design earthquakes for site-specific studies such as the siting of critical structures (power plants, waste disposals, large dams, etc.), strategic structures (fire stations, military commands, hospitals, etc.), or for seismic microzoning studies, matching the results of probabilistic seismic hazard analyses. This goal is achieved by calculating the source contribution to hazard and the magnitude–distance deaggregation, showing that, varying the selected frequency and the level of hazard, the reference earthquakes are changed as a result. A procedure is then adopted to minimize the residuals between the uniform hazard spectrum (target motion) and the design earthquake spectrum, to provide a specific earthquake scenario encompassing all the frequencies of the target motion. Finally, some considerations on the use and the influence exerted by ground motion uncertainty (σ) on hazard deaggregation are outlined.  相似文献   

Discontinuity controlled probabilistic slope failure risk maps of the Altindag (settlement) region in Turkey   总被引：7，自引：0，他引：7  

C. Gokceoglu  H. Sonmez  M. Ercanoglu 《Engineering Geology》2000,55(4):277-296

The evaluation of potential rock slope problems using stereographic projection techniques known as kinematic analysis is one of the most important parts of a slope stability investigation to be carried out in jointed rock media. In conventional stereoprojection techniques for the assessment of possible rock slope failures, the peak orientations of joints together with the slope geometry and the friction angle of the weakness planes are used. Other possible joint orientations which may be encountered in the rock media are ignored, although they belong to the group of joint peak orientations. In this study, nearly vertical jointed andesites cropped out at the Altindag settlement region in Ankara were studied in order to evaluate the relevance of this ignored discontinuity orientation data on slope stability. As a result, probabilistic risk maps for planar, toppling and wedge failures were produced using the kinematic rules and digital elevation model of the study area. The comparison of the distribution of the actual failures in the area and the probabilistic risk maps prepared for the study area revealed that all of the identified failures are found to be located in the higher risk zones on the probabilistic risk maps.  相似文献