汶川地震滑坡危险性评价——以武都区和文县为例

利用GIS技术详细研究汶川地震在甘肃省陇南市武都区和文县触发的滑坡地质灾害的分布规律及其与地震烈度、地形坡度、断层、高程、地层岩性的相关关系,采用基于GIS的加权信息量模型的崩塌滑坡危险性评价方法,对研究区的地震滑坡危险性进行学科分析。结果表明：极高危险区在高程上主要分布在集水高程区,高度危险区主要沿白水江、白龙江等主干河流两侧极高易发区的边界向两侧扩展,轻度和极轻度危险区面积占比较小,主要分布在低烈度、活动断裂不发育、人类活动微弱的高海拔地区,另外国道G215沿极高危险性区域分布明显;利用危险性等级分区结果统计人口公里格网数据,得到武都区和文县潜在影响人口,发现研究区约78万人将受到地震滑坡灾害的潜在影响。     

Extreme value analysis of diamond-size distributions

Extreme value analysis provides a semiparametric method for analyzing the extreme long tails of skew distributions which may be observed when handling mining data. The estimation of important tail characteristics, such as the extreme value index, allows for a discrimination between competing distribution models. It measures the thickness of such long tailed distributions, if only a limited sample is available. This paper stresses the practical implementation of extreme value theory, which is used to discriminate a lognormal from a mixed lognormal distribution in a case study of size distributions for alluvial diamonds.     

“Digital earth” in support of an online oceanic educational public service and popularization

According to the initial vision of "digital earth" (DE), the public should constitute a significant proportion of its users. However, to date, most of the studies and applications have focused on science, the private sector and government. A DE-supported online oceanic educational public service and popularization system, iOcean, is studied. First, the vision for the public’s engagement with "digital ocean" is described: an analysis is presented from four aspects, i.e., the space dimension, the time dimension, the state dimension and its relationship with human beings. Second, the technical framework of iOcean is discussed, including data updating and model computing, the data, the function, and the application layers. Third, two key technologies are studied in detail that will enable the construction of iOcean. More than half a million public viewers have used the current version’s website. Practical demonstrations show that iOcean can bring virtual oceans to web browsers and desktops and construct a bridge between government departments and the general public.     

Evaluating coastal scenery using fuzzy logic: Application at selected sites in Western Black Sea coastal region of Turkey

Coastal areas of the world are under treat due to the conflicting requirements of functions such as habitation and/or recreation, which affect the strategic asset of coastal scenery itself. Coastal managers, together with planners, need coastal landscape inventories, where the quality of coastal scenery is a part of the inventory. In order to provide an evidence-based approach for sound coastal management decisions, [Ergin et al., 2004] and [Ergin et al., 2006] developed a novel technique ‘coastal scenic evaluation’ (CSE), which addresses the evaluation of coastal scenery. The CSE technique utilizes fuzzy logic to derive values obtained from a checklist of 26 physical and human parameters. The methodology enables the calculation of an evaluation index (D), which categorizes the scenic values of coastal sites into five distinct classes. Using this technique, coastal scenic evaluations were carried out at 34 selected sites on the Western Black Sea coast of Turkey. Based on the calculated D values, a five-class differentiation was obtained for the selected sites, to provide baseline information for any envisaged subsequent management plans for these areas.     

辽东湾东部区块热带风暴设计增水的计算

以辽东湾东部区块出现的极值增水序列为例,考虑热带气旋过程出现频次的影响,采用泊松-最大熵复合极值分布进行了增水统计分析,计算得到辽东湾东部区块的增水重现值.最大100年一遇值为183cm,最大50年一遇值为158cm,皆出现于第1区块.由于受地形的影响,区块1、2与3的增水大小相似,区块4则略小.该结果对辽东湾东部区块...     

Effect of wave nonlinearity on fatigue damage and extreme responses of a semi-submersible floating wind turbine

Floating wind turbine has been the highlight in offshore wind industry lately. There has been great effort on developing highly sophisticated numerical model to better understand its hydrodynamic behaviour. A engineering-practical method to study the nonlinear wave effects on floating wind turbine has been recently developed. Based on the method established, the focus of this paper is to quantify the wave nonlinearity effect due to nonlinear wave kinematics by comparing the structural responses of floating wind turbine when exposed to irregular linear Airy wave and fully nonlinear wave. Critical responses and fatigue damage are studied in operational conditions and short-term extreme values are predicted in extreme conditions respectively. In the operational condition, wind effects are dominating the mean value and standard deviation of most responses except floater heave motion. The fatigue damage at the tower base is dominated by wind effects. The fatigue damage for the mooring line is more influenced by wind effects for conditions with small wave and wave effects for conditions with large wave. The wave nonlinearity effect becomes significant for surge and mooring line tension for large waves while floater heave, pitch motion, tower base bending moment and pontoon axial force are less sensitive to the nonlinear wave effect. In the extreme condition, linear wave theory underestimates wave elevation, floater surge motion and mooring line tension compared with fully nonlinear wave theory while quite close results are predicted for other responses.     

卫星双向法时间比对的归算

卫星双向法比对原理为两个台站同步发送和接收时间信号，可消除传递路径误差，因此比对精度高，它的缺点是效率低，占用大量卫星时间，也不适合于自动化操作，现正在研制的终端可多台站同时观测，克服了上述缺点，利用新的终端提出一种新的处理方法，研究表明多台站观测的同时性有更多的信息可提取，以提高比对精度。     

The Q value variations in the preparing pro－cess of rock rupture

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注水诱发地震的震源应力场和尾波衰减特征

利用区域性台网记录测定了任邱油田注水诱发地震的震源应力场和尾波衰减特征,结果表明地壳上层有很大水平应力,断层面解受注水井附近局部原生断层影响与华北现代应力场的优势破裂方向和错动方式有差别。地震应力降分布范围为0.2—3.0巴。平均尾波Q_0值为75,属于地壳上部沉积岩层的正常情况,发现在时间上表现出与注水量增减有关的波动。在空间上表现出震群密集区Q_0值较外围区偏低的特点     

时间域航空电磁数据的反演

本文用广义逆矩阵理论讨论了时间域航空电磁数据的反演方法.以水平二层大地和球体模型为例进行了计算,结果表明这种方法对时间域电磁数据的反演是行之有效的.对于理论数据,一般仅需迭代数次即可稳定地收敛到真值.通过奇异值分析,可以确定一个模型中的相对重要参数和无关紧要参数;对于求解某一特定参数,可确定哪些数据起决定性的作用.由奇异值分解而得出的信息密度矩阵、模型分辨矩阵,分别给出了模型响应拟合数据和模型参数分辨率的度量.这些信息对于时间域航空电磁系统的设计、野外测量和资料解释都具有重要的参考价值.最后给出了实例.