Statistical analysis of seismic data from north-western and western Argentina

Due to the process of subduction of the Nazca Plate, high seismic activity is observed near the Argentine Andean range between 21°S and 36°S. The new version of the Argentine Seismic Catalogue, which includes well-defined events during the period 1964–1989, allows us to perform an analysis of seismic risk.Earthquakes with epicenters in the provinces included in the north-western and western regions were studied using Gumbel III extreme value distribution. Modal extreme magnitudes and return periods were calculated for both regions and the results were compard with the ones obtained through the entire process techniques (both analytical and graphical).As a first study, we analyzed each province separately, after which mean values for each region were obtained. Modal values around 5–5.5 have been found and times of recurrence for events withm _b >6 of approximately 25 years were obtained.Also at CONICET (Consejo Nacional de Investigaciones Cientificas y Técnicas).     

小型水电站建设用地地质灾害评估技术研究——以湄尼多河小型水电站为例

现阶段,地质灾害评估技术人员在评估实践中,往往不注重各评估对象的差异性,采取同一评估模式,结果达不到评估的目的。在对小型水电站进行评估时,野外调查的重点,评估过程中所使用的方法以及危险性现状、预测及综合分区评估等与大型水电站、路线工程、矿山开采、民用建筑等工程有所不同。湄尼多河小型水电站工程位于云南省怒江州福贡县马吉乡境内,地质环境条件复杂,评估级别综合为二级。文章以该电站建设用地地质灾害危险性评估为例,对小型水电站建设用地地质灾害危险性评估的方法与理论进行探讨。     

The down-faulted basin zone and high disaster risk zone in Shanxi Province, China

Introduction Since 1920s, with increasing awareness of disaster prevention and reduction in various as-pects and gradually deepened development of International Decade for Natural Disaster Reduction (IDNDR) activities in China, the role and position of disaster risk analysis and risk management work are increasingly prominent. In the final report of the IDNDR activities in 1999, the Science and Technology Committee of IDNDR had presented 5 challenge fields, which the international dis…     

北京市蔬菜和菜地土壤砷含量及其健康风险分析

通过对北京市蔬菜和菜地土壤砷含量状况进行大规模调查,研究了蔬菜和土壤砷含量及其健康风险,并筛选出抗砷污染能力强的蔬菜品种。根据蔬菜的消费量并兼顾品种多样性的原则,在北京市规模化蔬菜栽培基地 (采集蔬菜及土壤样品) 和蔬菜批发市场 (蔬菜样品) 共采集93种蔬菜400多份蔬菜样品和39个土壤样品系统地分析其砷含量。研究发现：北京市菜地土壤砷含量范围和平均含量分别为4.44~25.3和9.40 mg/kg,明显超过北京市土壤砷背景值;北京市蔬菜砷含量最高达0.479 mg/kg,平均含量为0.028 mg/kg,均未超过《食品中砷限量卫生标准》(GB4810-94) 的限量值,但其中有2个蔬菜样品 (萝卜和大蒜) 砷含量超过WHO/FAO制订的限量标准。北京市蔬菜砷含量在东偏北方向 (偏转11^o-30^o) 存在明显的"U"型趋势分布。裸露地蔬菜砷含量显著高于设施蔬菜。油菜、萝卜、小白菜、大葱、芥菜、黄瓜、大白菜和甘蓝抗砷污染能力较弱,而辣椒、云架豆、冬瓜、茄子、菠菜、西红柿、芹菜等抗砷污染能力则较强。北京市居民从蔬菜中摄入砷平均值为0.016 mg/(人·d),蔬菜砷对北京市部分人群存在一定的健康风险。     

A new Likelihood Ratio for supervised classification of fully polarimetric SAR data: An application for sea ice type mapping

One of the potential applications of polarimetric Synthetic Aperture Radar (SAR) data is the classification of land cover, such as forest canopies, vegetation, sea ice types, and urban areas. In contrast to single or dual polarized SAR systems, full polarimetric SAR systems provide more information about the physical and geometrical properties of the imaged area. This paper proposes a new Bayes risk function which can be minimized to obtain a Likelihood Ratio (LR) for the supervised classification of polarimetric SAR data. The derived Bayes risk function is based on the complex Wishart distribution. Furthermore, a new spatial criterion is incorporated with the LR classification process to produce more homogeneous classes. The application for Arctic sea ice mapping shows that the LR and the proposed spatial criterion are able to provide promising classification results. Comparison with classification results based on the Wishart classifier, the Wishart Likelihood Ratio Test Statistic (WLRTS) proposed by Conradsen et al. (2003) and the Expectation Maximization with Probabilistic Label Relaxation (EMPLR) algorithm are presented. High overall classification accuracy of selected study areas which reaches 97.8% using the LR is obtained. Combining the derived spatial criterion with the LR can improve the overall classification accuracy to reach 99.9%. In this study, fully polarimetric C-band RADARSAT-2 data collected over Franklin Bay, Canadian Arctic, is used.     

A probabilistic methodology to estimate future coastal flood risk due to sea level rise

In this paper we present a methodology to estimate the probability of future coastal flooding given uncertainty over possible sea level rise. We take as an example the range of sea level rise magnitudes for 2100 contained in the IPCC Third Assessment Report [Church, J.A., Gregory, J.M., Huybrechts, P., Kuhn, M., Lambeck, K., Nhuan, M.T., Qin, D., Woodworth, P.L., Anisimov, O.A., Bryan, F.O., Cazenave, A., Dixon, K.W., Fitzharris, B.B., Flato, G.M., Ganopolski, A., Gornitz, V., Lowe, J.A., Noda, A., Oberhuber, J.M., O'Farrell, S.P., Ohmura, A., Oppenheimer, M., Peltier, W.R., Raper, S.C.B., Ritz, C., Russell, G.L., Schlosser, E., Shum, C.K., Stocker, T.F., Stouffer, R.J., van de Wal, R.S.W., Voss, R., Wiebe, E.C., Wild, M., Wingham, D.J. and Zwally, H.J., 2001. Changes in sea level. In Houghton, J.T. et al. (eds), Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom, 881pp.] and infer a plausible probability distribution for this range. We then use a Monte Carlo procedure to sample from this distribution and use the resulting values as an additional boundary forcing for a two-dimensional model of coastal inundation used to simulate a 1 in 200 year extreme water level event. This yields an ensemble of simulations for an event of this magnitude occurring in 2100, where each member represents a different possible scenario of sea level rise by this time. We then develop a methodology to approximate the probability of flooding in each model grid cell over the ensemble and by combining these hazards maps with maps of land use values (consequence) we are able to estimate spatial contributions to flood risk that can aid planning and investment decisions. The method is then applied to a 32 km section of the UK coast in Somerset, South-West England and used to estimate the monetary losses and risk due a 1 in 200 year recurrence interval event under: (a) current conditions; (b) with the IPCC's most plausible value for sea level rise by 2100 (0.48 m) and (c) using the above methodology to fully account for uncertainty over possible sea level rise. The analysis shows that undertaking a risk assessment using the most plausible sea level rise value may significantly underestimate monetary losses as it fails to account for the impact of low probability, high consequence events. The developed method provides an objective basis for decisions regarding future defence spending and can be easily extended to consider other sources of uncertainty such as changing event frequency–magnitude distribution, changing storm surge conditions or model structural uncertainty, either singly or in combination as joint probabilities.     

滑坡易发性危险性风险评价例析

从易发性、危险性、风险的概念入手,依据国际上流行和通用的滑坡风险评价与管理理论,分析了易发性评价的内容,包括易发性评价到危险性评价需要增加的评价要素,以及从危险性评价到风险评价需要增加的评价要素,阐明了这三种评价之间的联系和区别。并通过延安宝塔区的滑坡易发性、危险性和风险的评价与区划具体说明三者的做法和结果。     

“一带一路”沿线国家矿业投资风险评价——基于改进的灰色关联分析模型

随着共建“一带一路”倡议的推进,中国对沿线国家矿业投资稳步增长。由于部分国家特殊的政治、经济、文化背景,使得投资活动常面临众多风险,因此,有必要对矿业投资风险进行科学评价,以提高风险抵御能力。以国际投资风险一体化分析框架为基础,提出从社会一般环境与行业一般环境2个维度展开的矿业投资风险评价“四层次”指标体系,然后运用灰色系统理论的重要工具灰色关联分析对指标体系进行了实证研究。研究结果表明,政局稳定程度是影响矿业投资风险的首要因素,其次为外交关系情况、基础设施建设、矿产资源禀赋、对外单项投资和国民教育水平;以国别进行风险评价的研究结果表明,越南、印度尼西亚等为低风险国家,哈萨克斯坦、波兰等为中风险国家,巴基斯坦、伊朗等为高风险国家。     

矿产勘查与评估的统计地球化学方法

统计地球化学在矿产勘查与评估中的应用，主要包括采术规则，临界品位计算，资源量／储量公式，边界品位确定，网度判别，矿床经济分类以及矿床开发风险等内容。     

金沙江水电站工程区典型单体滑坡风险评价探讨

在对金沙江流域内的部分大型水电站工程区内的滑坡分析基础上,以两个滑坡为例,针对水电站工程区讨论了单体滑坡的风险评价方法。选取滑坡稳定性,规模和可能造成的涌浪高度3个指标进行危险性评价;并且定性地将大坝的易损性确定为高、中、低三个等级。在此基础上,对研究区的牛滚函滑坡和东岳庙滑坡进行了危险性分析和易损性评价,得出这两个单体滑坡的风险分析结果：牛滚函滑坡为低度风险,东岳庙滑坡为中度风险。研究成果为水电站工程区滑坡减灾防灾与风险管理提供了科学依据。