Probabilistic winter storm risk assessment for residential buildings in Germany

Losses resulting from winter storms contribute a significant part to the overall losses among all natural hazards in most mid-latitude European countries. A realistic assessment of storm risk is therefore essential for prevention and coping measures. The paper presents a framework for probabilistic storm risk assessment for residential buildings which is exemplarily performed for Germany. Two different approaches are described, and results are presented. The hazard-based approach brings together hazard, vulnerability and building assets to calculate risk curves for each community. The storm-based approach uses loss information from past storm events to calculate statistical return periods of severe storms. As a result, a return period of 83 years to the most severe storm series in 1990 is calculated. Average annual losses of €170 million to residential buildings are calculated for all over Germany. The study demonstrates how the approaches complement each other and how validation is performed.     

钱塘江河口杭州湾风暴潮溢流计算方法研究

建立钱塘江河口杭州湾风暴潮模型,探讨风暴潮出现溢流的计算方法。将可能出现溢流的沿海堤防以及海水侵入的陆地均依照高程概化为计算区域,采用糙率控制潮水的溢流流量,以模型的堤顶单宽流量和根据计算潮位采用宽顶堰公式换算流量的一致性来率定糙率值。在此基础上模拟了风暴潮漫溢堤防的过程,结果表明风暴潮出现溢流后,钱塘江河口杭州湾之间两岸大片的陆地存在淹没风险,沿程潮位由于溢流出现不同程度的降低响应。     

灌区干旱风险评估模型研究

根据风险理论,建立了包括农业干旱发生概率、抗旱能力、受灾体种植面积比等多因子的灌区农业干旱风险评估模型。并将相对产量作为灌区农业干旱评估指标,能够反映土壤 作物 大气系统中水分运动对农业生产的影响,利用该指标结合干旱风险评估模型对灌区农业干旱进行风险评估,分析出灌区各种作物对干旱风险度影响最大的生育阶段和风险度最高的农作物,以便灌区制定合理的抗旱方案以减小灌区干旱损失。     

The impact of extra-tropical transitioning on storm surge and waves in catastrophe risk modelling: application to the Japanese coastline

Catastrophe risk models are used to assess and manage the economic and societal impacts of natural perils such as tropical cyclones. Large ensembles of event simulations are required to generate useful model output. For example, to estimate the risk due to wind-driven storm surge and waves in tropical cyclone risk models, computationally efficient parametric representations of the wind forcing are required to enable the generation of large ensembles. This paper presents new results on the impact of including explicit representations of extra-tropical transitioning in parametric wind models used to force storm surge and wave simulations in a catastrophe risk modelling context. Extra-tropical transitioning is particularly important in modelling risk on the Japanese coastline, as roughly 40 % of typhoons hitting the Japanese mainland are transitioning before landfall. Using both a historical and idealized track set, we compare maximum storm surge and wave footprints along the Japanese coastline for models that include, and do not include, explicit representations of extra-tropical transitioning. We find that the inclusion of extra-tropical transitioning leads to lower storm surge (10–20 %) and waves (5–15 %) on the southern Japanese coast, with significantly higher storm surge and waves along the northern coast (25–50 %). The results of this paper demonstrate that useful risk assessment of coastal flood risk in Japan must consider the extra-tropical transitioning process.     

Regional debris-flow distribution and preliminary risk assessment from severe storm events in the Appalachian Blue Ridge Province,USA

Storms of high-intensity rainfall, including hurricanes, occur about once every 3 years in small areas of the mountains of the eastern United States posing a high debris-flow hazard. Reported casualties and monetary losses are often an insufficient and inadequate means for comparing the impact from debris flows. A simple GIS technique was used to characterize the distribution and density of debris flows for making a preliminary assessment of risk of impact on roads. This technique was used for comparison of three major severe storms resulting in numerous debris flows: August 10–17, 1940, near Deep Gap, North Carolina; August 19–20, 1969, in Nelson County, Virginia; and June 27, 1995, in Madison County, Virginia. Based on the criteria of the number of debris flows and area covered by debris flows, the August 19–20, 1969, Nelson County, Virginia, event was the most severe of the three storms and posed the greatest risk of debris-flow impact on roads.     

The structural vulnerability in the framework of natural hazard risk analyses and the exemplary application for storm loss modelling in Tyrol (Austria)

In the context of natural hazard-related risk analyses, different concepts and comprehensions of the term risk exist. These differences are mostly subjected to the perceptions and historical backgrounds of the different scientific disciplines and results in a multitude of methodological concepts to analyse risk. The target-oriented selection and application of these concepts depend on the specific research object which is generally closely connected to the stakeholders’ interests. An obvious characteristic of the different conceptualizations is the immanent various comprehensions of vulnerability. As risk analyses from a natural scientific-technical background aim at estimating potential expositions and consequences of natural hazard events, the results can provide an appropriate decision basis for risk management strategies. Thereby, beside the preferably addressed gravitative and hydrological hazards, seismo-tectonical and especially meteorological hazard processes have been rarely considered within multi-risk analyses in an Alpine context. Hence, their comparative grading in an overall context of natural hazard risks is not quantitatively possible. The present paper focuses on both (1) the different concepts of the natural hazard risk and especially their specific expressions in the context of vulnerability and (2) the exemplary application of the natural scientific-technical risk concepts to analyse potential extreme storm losses in the Austrian Province of Tyrol. Following the corresponding general risk concept, the case study first defines the hazard potential, second estimates the exposures and damage potentials on the basis of an existing database of the stock of elements and values, and third analyses the so-called Extreme Scenario Losses (ESL) considering the structural vulnerability of the potentially affected elements at risk. Thereby, it can be shown that extreme storm events can induce losses solely to buildings and inventory in the range of EUR 100–150 million in Tyrol. However, in an overall context of potential extreme natural hazard events, the storm risk can be classified with a moderate risk potential in this province.     

黄骅地区水-土系统地球化学环境健康风险评估

对黄骅地区土壤、粮食籽实(小麦、玉米)及饮用水中出现严重污染的元素进行风险分析和风险评估,划分风险管理分区并提出相应管理措施.笔者结合土壤、粮食籽实(小麦、玉米)及饮用水样品中超标元素,综合分析后选取Cd、Cu、Hg、Pb、Zn、As、Ni、F、I、Se、Cr共11种重点元素作为风险评估的指标,建立人体单位体重日均食用暴露剂量模型(CDI),并采用风险商值法进行风险等级划分,并将多种元素的风险区域合并叠加形成风险管理分区.结果显示,黄骅地区11个评估指标中F的风险系数HQ值全部大于1,I的HQ值大于1的样品占52%,Pb只有一个样品的HQ值大于1,其他元素的HQ值全区均小于1.水土综合高风险区主要出现在黄骅西南部常郭-旧城-羊二庄一带,次高风险区为北部齐家务、南排河,风险主要由地下水引起.     

Street-scale storm surge load impact assessment using fine-resolution numerical modelling: a case study from Nemuro,Japan

Natural Hazards - Due to gradual sea level rise and changes in the climate system, coastal vulnerability to storm surge hazards is expected to increase in some areas. Studies regarding the effect...     

Geodetic monitoring of tectonic deformation in the Australian region

A number of geodetic techniques exist for measuring instantaneous crustal motions and deformations. Over distances of a few hundred kilometres, conventional terrestrial methods can achieve accuracies of about 1–2 parts in 10⁶ for horizontal positions, but most existing triangulation networks in Australia are of lower accuracies. Geodetic levelling can provide height‐difference measurements with an accuracy of a few mm for points separated by about 100 km, but actual accuracies are often much lower than this. For points separated by longer distances, from a few 100 km to several 1000 km, space techniques can provide precisions of 5–10 cm. Two experiments carried out in Australia confirm that these precisions can be reached. A laser ranging experiment between sites near Canberra and Perth produced a baseline that is precise to better than 10 cm, and a radio‐interferometry experiment between Canberra, Parkes and Sydney produced baselines with precisions of 10 cm. Further evaluation of both systems is required, but the present results indicate that crustal deformations of the order of 10 cm can be measured with repeat surveys.     

Landslides in Emilia-Romagna region (Italy): strategies for hazard assessment and risk management

In Emilia-Romagna, over 32,000 landslide bodies cover one-fifth of the hilly and mountainous territory. The majority of them originated as earth-flows after the last glacial maximum and grew during the rainiest periods of the Holocene through the superimposition of new earth-flows. Reactivation of these large landslides is the main problem the geologists of Emilia-Romagna are facing now. Intense and/or prolonged precipitation play a major role as triggering factors in reactivating landslide bodies, but also the importance of snowmelt is suggested by the monthly distribution of landslide events. Almost all the present-day landslide activity is due to the reactivation of pre-existing landslide bodies. Consequently, territorial planning and geo-thematic cartography are fundamental tools for the reduction of risk. The Emilia-Romagna geo-thematic cartography (1:10,000) is legally binding and regulates land use in regional, municipal and basin plans.     

断裂性质与滑坡分布的关系——以汶川地震中的大型滑坡为例

美姑河流域地处全球滑坡灾害密集的云贵高原与川西南山地过渡带,该地区因地貌类型特殊,大型-巨型滑坡数量多、危害重、成因机理复杂,成为河谷区重大工程和城镇建设的安全隐患。笔者在国内外古滑坡研究成果分析的基础上,总结了美姑河流域古滑坡时空展布、滑坡对顺构造地貌响应、滑坡孕灾-控灾机理,滑坡成灾模式与主控因素等方面的研究进展。结合当前滑坡防灾减灾实际需求,提出美姑河流域顺构造地貌控制下古滑坡孕灾模式研究的3个优选方向：(1)不同发育强度的顺构造地貌对滑坡孕灾-控灾模式,(2)构造差异隆升对顺构造地貌区大型滑坡发育的孕灾模式,(3)通过古滑坡年代学研究建立断裂、褶皱、古地震和古气候变化与滑坡发育的对应联系。破解这些研究方向的关键科学问题,将为西南山区古滑坡研究及防灾减灾起到积极指导作用。     

A statistical approach to landslide risk modelling at basin scale: from landslide susceptibility to quantitative risk assessment

A procedure for landslide risk assessment is presented. The underlying hypothesis is that statistical relationships between past landslide occurrences and conditioning variables can be used to develop landslide susceptibility, hazard and risk models. The latter require also data on past damages. Landslides occurred during the last 50 years and subsequent damages were analysed. Landslide susceptibility models were obtained by means of Spatial Data Analysis techniques and independently validated. Scenarios defined on the basis of past landslide frequency and magnitude were used to transform susceptibility into quantitative hazard models. To assess vulnerability, a detailed inventory of exposed elements (infrastructures, buildings, land resources) was carried out. Vulnerability values (0–1) were obtained by comparing damages experienced in the past by each type of element with its actual value. Quantitative risk models, with a monetary meaning, were obtained for each element by integrating landslide hazard and vulnerability models. Landslide risk models showing the expected losses for the next 50 years were thus obtained for the different scenarios. Risk values obtained are not precise predictions of future losses but rather a means to identify areas where damages are likely to be greater and require priority for mitigation actions.     

Risk assessment on storm surges in the coastal area of Guangdong Province

The coastal area of Guangdong Province is one of the most developed regions in China. It is also often under severe risk of storm surges, as one of the few regions in China which are seriously threatened by storm surges. Based on the data of storm surges in the study area in the past 30 years, the return periods of 18 tide stations for storm surge are calculated separately. Using the spatial analysis technology of ArcGIS, combined with the topography data of the study area, the submerged scope for storm surge in the coastal area of Guangdong Province is determined, and the hazard assessment is carried out. According to the view of systematic point, this article quotes the result of vulnerability assessment which was done by the author in the previous research. Based on the hazard evaluation and vulnerability evaluation, risk assessment of storm surges in the study region is done, and the risk zoning map is drawn. According to the assessment, Zhuhai, Panyu and Taishan are classified as the highest risk to storm surges in Guangdong Province; Yangdong, Yangjiang and Haifeng are in higher risk to storm surges; Dongguan, Jiangmen, Baoan and Huidong are in middle risk to storm surges; Zhongshan, Enping, Shanwei, Huiyang, Longgang and Shenzhen are in lower risk of storm surges; Guangzhou, Shunde and Kaiping are in the lowest risk to storm surges. This study builds a complete process for risk assessment of storm surges. It reveals the risk of storm surges in the coastal cities, and it would guide the land use of coastal cities in the future and provide scientific advices to the government for the prevention and mitigation of storm surge disaster. It has important theoretical and practical significance.     

Hazard risk assessment of landslide-prone sub-Himalayan region by employing geospatial modeling approach

Natural Hazards - Ecological processes such as landslide disaster are primarily impacted by both geological and land use activities happening at different spatiotemporal scale. They specifically...     

Correction to: Street-scale storm surge load impact assessment using fine-resolution numerical modelling: a case study from Nemuro,Japan

Natural Hazards - To: Street-scale storm.     

Physical and numerical modelling of infiltration from drainage holes for perforated storm sewer

In cities, the existence of impervious structures, such as road pavements, parking lots, footpaths, sidewalks, and roofs, can limit the magnitude of rainfall infiltration greatly. Stormwater run-off in storm sewer often dominates, which can cause problems of urban flooding easily during heave rainfalls. In rain and sewage diversion, perforated storm sewer is proposed to enable the occurrence of stormwater infiltration into the ground, which can change the prolonged drought-like condition. Model-scale laboratory tests are conducted to assess the infiltration process of water through drainage holes around the sewer circumference. The experimental data are also used to calibrate a numerical model, after which numerical parametric analysis is carried out. It is found that the feature of drainage holes only influences the wetting front in the initial stage of infiltration. In the end, the egg-shaped contour of wetting front with greater influencing zone below the sewer is obtained. The cumulative infiltration with time can be described by an infiltration model, which is positively correlated with the diameter and the number of drainage holes. The optimal opening ratio is recommended as 0.25%, which can provide the most effective drainage capacity.