GIS线目标间拓扑关系描述的4交差模型   总被引：3，自引：0，他引：3  

邓敏  李志林  李永礼  张雪松 《武汉大学学报(信息科学版)》2006,31(11):945-949

提出了利用连通度不变量来区分单个线目标上具有不同拓扑特性的点，进一步定义了线目标的端点集和内点集。在此基础上，建立了IR^1和IR^2中线目标间拓扑关系的基本模型。该模型能有效地表达线目标间拓扑关系的变化特性。  相似文献   

地闪回击电流测量综述     

王飞  张义军  孟青  吕伟涛 《气象》2006,32(8):3-11

地闪回击电流是雷电的一个重要特征参数。其测量数据的积累对于雷电防护技术的提高具有重要意义。目前国内外的雷电研究人员通过矮塔、高塔直接观测，人工引雷观测和电场电流关系反衍的方法对地闪回击电流进行了大量的观测研究，并取得了丰富的观测资料。观测表明，负地闪首次回击电流平均为30kA，继后回击电流平均12kA。正地闪回击电流平均为35kA，有时可达几百kA。不同地区地闪回击电流平均值略有不同。高塔测量是主要的雷电流参量直接测量方法，但不同高度测量的地闪回击电流无论峰值还是波形都存在一定的差异。人工引发闪电和自然闪电继后回击雷电流的测量结果较为一致。间接估测雷电流参数的方法随着地闪回击模式的发展将成为主要的方法之一。  相似文献   

多尺度空间对象拓扑相似关系的表达与计算   总被引：13，自引：0，他引：13  

吕秀琴  吴凡 《测绘信息与工程》2006,31(2):29-31

研究了空间数据多尺度表达中,在进行模型综合时空间对象拓扑关系的表达、变化和相似性。基于空间对象之间拓扑关系的概念邻域,给出了空间对象拓扑关系相似性的定义以及在数字景观模型中拓扑关系相似性的度量方法,为空间数据的多尺度表达提供了拓扑关系分析和评价手段。  相似文献   

东南沿海地区的断裂与地震   总被引：1，自引：0，他引：1  

卢帮华  黄日恒 《华南地震》2006,26(3):109-118

中国东部,相对来说东南沿海地区的地震活动较为频繁,断裂构造也十分发育。地震活动与断裂构造有非常密切的关系,震中与断裂构造的空间分布也关系密切。通过对东南沿海大量震例的调查和研究,分析三组断裂与地震的关系,得出东南沿海地区东西向、北东向和北西向的三组断裂构造,分别构成了区内的衰减构造、控震构造和发震构造,形成了东南沿海陆缘构造活动带。  相似文献   

M L Determination for Local and Regional Events Using a Sparse Network in Southwestern Germany     

Stefan Stange 《Journal of Seismology》2006,10(2):247-257

A method for the determination of consistent local magnitude M _L values (Richter scale, or M _WA) for earthquakes with epicentral distances ranging from 10 km through 1000 km is demonstrated. The raw data consists of nearly 1300 amplitude readings from a network of six digital seismographs in Baden–Württemberg (Southwestern Germany) during 26 months starting in 1995, later extended by another 1000 amplitude readings until 1999. Relying on most of the basics introduced by C.F. Richter a three-parameter attenuation curve (distance correction, magnitude-distance relation) for Baden–Württemberg and adjacent areas is presented. Station corrections are evaluated and the attenuation curve is calibrated with respect to other agencies for distances greater than 650 km. Reasonable parametrisations are discussed and meaningful error bars are attributed. Finally, a seventh station is incorporated by means of its station correction alone, without needing to update the attenuation curve.  相似文献   

A preliminary investigation of strong-motion data from the French Antilles     

John Douglas  Didier Bertil  Agathe Roullé  Pascal Dominique  Philippe Jousset 《Journal of Seismology》2006,10(3):271-299

Strong-motion networks have been operating in the Caribbean region since the 1970s, however, until the mid-1990s only a few analogue stations were operational and the quantity of data recorded was very low. Since the mid-1990s, digital accelerometric networks have been established on islands within the region. At present there are thought to be about 160 stations operating in this region with a handful on Cuba, 65 on the French Antilles (mainly Guadeloupe and Martinique), eight on Jamaica, 78 on Puerto Rico (plus others on adjacent islands) and four on Trinidad.After briefly summarising the available data from the Caribbean islands, this article is mainly concerned with analysing the data that has been recorded by the networks operating on the French Antilles in terms of their distribution with respect to magnitude, source-to-site distance, focal depth and event type; site effects at certain stations; and also with respect to their predictability by ground motion estimation equations developed using data from different regions of the world. More than 300 good quality triaxial acceleration time-histories have been recorded on Guadeloupe and Martinique at a large number of stations from earthquakes with magnitudes larger than 4.8, however, most of the records are from considerable source-to-site distances. From the data available it is found that many of the commonly-used ground motion estimation equations for shallow crustal earthquakes poorly estimate the observed ground motions on the two islands; ground motions on Guadeloupe and Martinique have smaller amplitudes and are more variable than expected. This difference could be due to regional dependence of ground motions because of, for example, differing tectonics or crustal structures or because the ground motions so far recorded are, in general, from smaller earthquakes and greater distances than the range of applicability of the investigated equations.  相似文献   

Seismic hazard assessment for derivation of earthquake scenarios in Risk-UE     

Ezio Faccioli 《Bulletin of Earthquake Engineering》2006,4(4):341-364

The main features of the Risk-UE project approach to assessing the ground-shaking (and related hazards) distribution within urban areas are described, as a basis for developing seismic damage scenarios for European cities. Emphasis was placed in the project on adoption of homogeneous criteria in the quantitative treatment of seismicity and in constructing the ground-shaking scenarios, despite wide differences in amount and quality of data available for the cities involved. The initial steps of the approach include treatment of the regional seismotectonic setting and the geotechnical zonation of the urban area, while the hazard assessment itself takes the form of both a deterministic analysis, and of a probabilistic, constant-hazard spectra analysis. Systematic 1D site response analyses were used, mostly in the softer soil zones, to modify (when needed) the obtained ground motion maps. Earthquake induced hazard effects, such as liquefaction and landsliding, are also briefly dealt with at the end.  相似文献   

地震安全性评价工程师资格考试大纲已审定通过   总被引：12，自引：0，他引：12  

本刊讯 《震灾防御技术》2006,1(3):217-217

把美国西部地区作为参考区,采用我国地震动参数区划图工作时所使用的美国西部地区强震资料建立参考区水平向基岩短周期加速度反应谱衰减关系;采用美国南加州地区数字宽频带记录建立参考区水平向基岩长周期加速度反应谱衰减关系。与由丰富的等震线资料统计得出的我国东部地区和西部地区的地震烈度衰减关系一起,用转换方法分别得到了我国东部和西部地区水平向基岩加速度反应谱衰减关系。对该衰减关系在重大工程地震安全性评价工作中的应用提出了建议。  相似文献   

湖南省中南部地区地震区划研究   总被引：3，自引：0，他引：3  

李颖  胥广银  陈鲲  高孟潭 《中国地震》2007,23(1):17-24

选择湖南省中南部地区作为研究区域,以编制《中国地震动参数区划图》的基础资料和近年来在湖南省中南部所作的工程场地地震安全性评价资料为基础,根据近年来对中强地震衰减关系的研究结果,以及1970年以来现代仪器记录得到的地震资料确定的研究区域背景地震活动水平及其参数,对湖南省中南部地区进行了新的地震区划研究。结果表明,考虑了中强地震衰减关系,并重新考虑背景地震活动水平后,湖南中南部地区地震区划结果与现行区划图相比,地震动峰值加速度达0·05g的区域显著增加,其中包括邵阳、湘潭、吉首、怀化等重要城市。研究结果与近年来湖南中南部地区发生的中小地震的高震害特征比较吻合。本文的研究结果对于地震活动主要以6级以下中强地震活动为主的我国中东部地区的地震区划研究以及编制新一代地震动参数区划图都具有重要的参考意义。  相似文献   

多尺度下的不确定性空间方向锥形模型研究     

蔡剑红  李德仁 《武汉大学学报(信息科学版)》2007,32(8):735-739

利用质心作为参考点,并在空间方向锥形模型中添加了扩展不确定度的参数,用区间分析法,对多尺度下顾及不确定性的空间方向关系进行形式化描述,来适应尺度变化引起的空间关系不确定性的变化,以更好地描述空间方向关系。该模型使得方向关系的划分上有个平滑的过渡区,在方向概念的表达上更符合人的认知。  相似文献