The Tornado Hazard In Southern New England: History,Characteristics, Student And Teacher Perceptions     

《The Journal of geography》2012,111(6):258-266

Abstract

People generally do not perceive New England to be tornado-prone. Yet, there is a long history of such storms in the six states going back to the late seventeenth century. Usually, New England tornadoes are small and short-lived; even so, some have caused many deaths and much property damage. There is a greater probability for a person to be affected by a tornado in southern New England than in much of the American Midwest. As building and population density increases, so does the hazard potential. Data from awareness surveys indicate that the lack of tornado knowledge remains a serious problem for teachers, students, and the public, and government information about such storms is not being widely disseminated.  相似文献   

Perfluoroalkyl and polyfluoroalkyl substances in sediments from South Bohai coastal watersheds,China     

Zhaoyun Zhu  Tieyu Wang  Pei Wang  Yonglong Lu  John P. Giesy 《Marine pollution bulletin》2014

This study investigated the concentrations and distribution of Perfluoroalkyl and polyfluoroalkyl substances (PFAS) in sediments of 12 rivers from South Bohai coastal watersheds. The highest concentrations of ΣPFAS (31.920 ng g⁻¹ dw) and PFOA (29.021 ng g⁻¹ dw) were found in sediments from the Xiaoqing River, which was indicative of local point sources in this region. As for other rivers, concentrations of ΣPFAS ranged from 0.218 to 1.583 ng g⁻¹ dw were found in the coastal sediments and from 0.167 to 1.953 ng g⁻¹ dw in the riverine sediments. Predominant PFAS from coastal and riverine areas were PFOA and PFBS, with percentages of 30% and 35%, respectively. Partitioning analysis showed the concentrations of PFNA, PFDA and PFHxS were significantly correlated with organic carbon. The results of a preliminary environmental hazard assessment showed that PFOS posed the highest hazard in the Mi River, while PFOA posed a relative higher hazard in the Xiaoqing River.  相似文献   

Quantifying the epistemic uncertainty in ground motion models and prediction     

《Soil Dynamics and Earthquake Engineering》2014

The aim of this paper is to compute the ground-motion prediction equation (GMPE)-specific components of epistemic uncertainty, so that they may be better understood and the model standard deviation potentially reduced. The reduced estimate of the model standard deviation may also be more representative of the true aleatory uncertainty in the ground-motion predictions.The epistemic uncertainty due to input variable uncertainty and uncertainty in the estimation of the GMPE coefficients are examined. An enhanced methodology is presented that may be used to analyse their impacts on GMPEs and GMPE predictions. The impacts of accounting for the input variable uncertainty in GMPEs are demonstrated using example values from the literature and by applying the methodology to the GMPE for Arias Intensity. This uncertainty is found to have a significant effect on the estimated coefficients of the model and a small effect on the value of the model standard deviation.The impacts of uncertainty in the GMPE coefficients are demonstrated by quantifying the uncertainty in hazard maps. This paper provides a consistent approach to quantifying the epistemic uncertainty in hazard maps using Monte Carlo simulations and a logic tree framework. The ability to quantify this component of epistemic uncertainty offers significant enhancements over methods currently used in the creation of hazard maps as it is both theoretically consistent and can be used for any magnitude–distance scenario.  相似文献   

云南鲁甸6.5级地震灾害特点浅析   总被引：5，自引：4，他引：1  

帅向华  姜立新  侯建盛  延旭东  宋立军  刘爱文 《震灾防御技术》2014,9(3):340-358

通过对2014年8月3日云南鲁甸6.5级地震震害开展实地调查,对灾区破坏情况进行总体介绍,并就各烈度区特征和建筑物震害、地震地质灾害、工程结构震害进行分析,初步得出本次地震的一些震害特点.一是灾区人口密度大,人员死亡较集中.人员死亡主要集中在Ⅷ和Ⅸ度区.二是地震振动强,灾区破坏严重.本次地震震源深度12km,极震区烈度高达Ⅸ度,震源破裂在11s内集中释放.三是抗震能力弱,房屋破坏严重.灾区属国家级贫困区,农村民居抗震能力弱,且多数民房坐落在河谷陡坡上,边坡效应加重房屋震害,重灾区砖木和土木房屋成片损毁、倒塌.四是灾区条件恶劣,救灾难度大.震区活动断裂密集发育、地质破碎疏松、地形崎岖不平,又恰值雨季,诱发极其严重次生地质灾害,导致人员伤亡,造成灾区大面积交通、通信、电力中断,救援物资与救援力量无法及时发挥作用.  相似文献   

南阳膨胀土的宏观结构与路堑边坡病害治理     

冯玉勇  曲永新  徐卫亚 《工程地质学报》2005,13(2):169-173

南阳盆地是我国膨胀土主要分布地区之一,在宁(南京)西(西安)铁路施工工程地质调查中,发现南阳地区上第三系中新统湖相沉积膨胀土中发育的构造裂隙、中更新统冲洪积膨胀土中发育的卸荷裂隙和全新统湖沼相膨胀土中发育的收缩裂隙控制了路堑边坡病害的形式、规模和破坏特征。施工过程中采取了针对性措施治理边坡病害,取得了明显的工程效果。  相似文献   

Integrating Uncertainty Theories with GIS for Modeling Coastal Hazards of Climate Change     

Peter J. Cowell  Thomas Q. Zeng 《Marine Geodesy》2013,36(1-2):5-18

Prediction of coastal hazards due to climate change is fraught with uncertainty that stems from complexity of coastal systems, estimation of sea level rise, and limitation of available data. In-depth research on coastal modeling is hampered by lack of techniques for handling uncertainty, and the available commercial geographical information systems (GIS) packages have only limited capability of handling uncertain information. Therefore, integrating uncertainty theory with GIS is of practical and theoretical significance. This article presents a GIS-based model that integrates an existing predictive model using a differential approach, random simulation, and fuzzy set theory for predicting geomorphic hazards subject to uncertainty. Coastal hazard is modeled as the combined effects of sea-level induced recession and storm erosion, using grid modeling techniques. The method is described with a case study of Fingal Bay Beach, SE Australia, for which predicted responses to an IPCC standard sea-level rise of 0.86 m and superimposed storm erosion averaged 12 m and 90 m, respectively, with analysis of uncertainty yielding maximum of 52 m and 120 m, respectively. Paradoxically, output uncertainty reduces slightly with simulated increase in random error in the digital elevation model (DEM). This trend implies that the magnitude of modeled uncertainty is not necessarily increased with the uncertainties in the input parameters. Built as a generic tool, the model can be used not only to predict different scenarios of coastal hazard under uncertainties for coastal management, but is also applicable to other fields that involve predictive modeling under uncertainty.  相似文献   

新疆尼勒克、巩留交界MS6．0地震灾害损失评估与房屋震害特征     

谭明  唐丽华  吴国栋  常想德  张勇  宋立军  李洋  李亦纲  王伟  石广岭  李志海 《内陆地震》2012,26(3):209-220

新疆尼勒克、巩留交界MS6．0地震震中烈度为Ⅶ度,地震没有造成人员伤亡,但个别民宅倒塌,大量村镇居民房屋遭受中等以上破坏,一些教育、卫生等公房遭破坏;交通和水利设施有一定程度破坏,经及时抢修,未对灾区生产生活产生明显影响。通过实地抽样调查和统计计算,评估出本次地震造成的直接经济损失为67846万元,恢复重建的经费需120349万元。  相似文献   

网络地震灾情信息智能处理模型与地震烈度判定方法研究   总被引：2，自引：2，他引：0  

胡素平  帅向华 《震灾防御技术》2012,7(4):420-430

破坏性地震发生之后,丰富的地震灾情信息和准确的地震烈度图是地震应急救援工作的基础。伴随着互联网的迅速发展,互联网已经成为地震灾情信息获取的一种重要渠道。本文通过构建网络地震灾情信息智能处理模型,将互联网上非结构化的灾情信息转化成结构化的灾情信息。并将网络地震灾情信息与地震烈度相结合,进行地震烈度判定,从而对地震应急期的烈度快速评定结果进行修正拟合。  相似文献   

Landslide hazard mapping along the coastline of the Cilento region (Italy) by means of a GIS-based parameter rating approach   总被引：2，自引：1，他引：1  

P. Budetta  A. Santo  F. Vivenzio   《Geomorphology》2008,94(3-4):340

This paper deals with the heuristic approach used for landslide hazard zonation along the coastal slopes and cliffs of the Cilento region between Agropoli and Sapri (Italy). This sector of coastline (about 118 km in length) is formed mainly of Mesozoic carbonates and Miocene flysch; Quaternary marine sandstones together with beach sands also crop out. Due to the destructive force of the waves, the coastline is affected by several landslides (mainly rock-falls and slides). The major geomorphological, geological and structural features of about 154 slopes and cliffs have been analysed and several parameters affecting the rock-masses were detected and measured. These parameters deal with topographical, geological, geomechanical, environmental and wave hydraulic characteristics of the studied area. In order to perform the heuristic approach, the Rock Engineering Systems (RES) proposed by Hudson was adopted with several modifications. The main steps of this work were: (1) the choice of parameters relevant to landslide hazard zonation, (2) the analysis of binary interaction between parameters, (3) the weighting of interaction importance, (4) the rating assignment to different classes of parameter values and (5) the final computation of an “Instability Index” (I.I.). A database containing the measured parameters was prepared, and using an interaction matrix, the outputs were linked into a Geographic Information System. It contains the following elements: geological and geomorphological features, historical data regarding landslides, images and values of I.I. for the studied slopes and cliffs. If new landslides occur or near-shore engineered structures are built, then the I.I. values will be automatically upgraded.Values of the I.I. were grouped into 3 classes marking low, medium and high landslide hazard. Both carbonatic rock-masses and flysch were distinguished with respect to I.I. values to show the differences in landslide susceptibility. In fact, rapid but small rock-falls can cause more casualties than moderate speed but large slides. High landslide hazard affects about 41% of carbonate cliffs and about 53% of slopes in arenaceous-marly flysch.  相似文献   

A Neogene giant landslide in Tarapacá, northern Chile: A signal of instability of the westernmost Altiplano and palaeoseismicity effects     

L. Pinto  G. Hrail  S.A. Sepúlveda  P. Krop 《Geomorphology》2008,102(3-4):532-541

Giant landslides, which usually have volumes up to several tens of km³, tend to be related to mountainous reliefs such as fault scarps or thrust fronts. The western flank of the Precordillera in southern Peru and northern Chile is characterized by the presence of such mega-landslides. A good example is the Latagualla Landslide (19°15′S), composed of ~ 5.4 km³ of Miocene ignimbritic rock blocks located next to the Moquella Flexure, a structure resulting from the propagation of a west-vergent thrust blind fault that borders the Precordillera of the Central Depression. The landslide mass is very well preserved, allowing reconstitution of its movement and evolution in three main stages. The geomorphology of the landslide indicates that it preceded the incision of the present-day valleys during the late Miocene. Given the local geomorphological conditions 8–9 Ma ago (morphology, slopes and probably a high water table), large-magnitude earthquakes could have provided destabilization forces enough to cause the landslide. On the other hand, present seismic forces would not be sufficient to trigger such landslides; therefore the hazard related to them in the region is low.  相似文献