某区域内地质灾害风险研究

为了最大程度减少因地质灾害伤亡和经济损失,研究了某区域地质灾害风险,主要地质灾害为崩塌、滑坡和地面塌陷,在GIS平台上,基于研究区数字高程模型(DEM)提取山脊、沟谷线,结合人工调整和现场调查结果等对研究区进行斜坡单元划分,共划分出327个评价单元;采用矩阵分析方法得出地质灾害风险性评价。研究得出,研究区地质灾害风险性评价结果将地质灾害防治区划分为重点防治区、次重点防治区、一般防治区,其中,重点防治区面积占研究区总面积的5.01%,次重点防治区面积占研究区总面积的20.20%,一般防治区面积占研究区总面积的74.79%。

农业水旱灾害风险评估及生态减灾研究——以衡阳市水旱灾情为例

衡阳市是湖南省水旱灾害较严重的地区之一。为了防御或减轻水旱灾害对农业生产的影响,必须在灾害风险分析基础上,寻找减灾对策。文中利用长时间序列的水旱灾害灾情资料,从受灾面积和减产等级两方面评估了衡阳市农业灾害的风险。得出衡阳市水旱灾害风险性较大,特别是衡阳市北部的衡山县、衡东县、衡阳县既面临着高风险的水灾也面临着高度的旱灾风险。灾害风险性可以看成是生态安全性的另一面,故加强生态安全建设可以降低水旱灾害风险性。为此本文提出了降低水旱灾害风险性的生态措施。

黄河羊曲水电站河岸缓冲带生态安全评价与功能区划

以羊曲水电站河岸缓冲带为研究对象,综合利用RS、GIS技术和多源数据,从生态安全角度分析了研究对象的生态敏感性和灾害风险性,建立了50、200、500和1500 m共4种不同宽度的河岸缓冲带,对库区河岸缓冲带的生态安全等级进行了分类划分与功能区划。结果表明:库区河岸缓冲带具有显著的空间分布特征,高度敏感区面积较大,高灾害和中灾害风险区占据了研究区的大部分,这些区域的生态系统面临较大的压力和威胁。提出了针对性的生态管理与保护策略,比如加强生态恢复工程建设、提升植被覆盖度和优化土地利用管理。同时,对库区河岸缓冲带的功能进行了划分,包括重点生态功能区、农产品主产区和城市化地区。

生态安全视角下的山地区域及河岸带功能区划分

山地地貌特点决定了河岸带不仅是水陆交界处重要的生态系统,也是受山洪威胁严重的区域,如何协调防洪安全与生态保护之间的矛盾是山地区域河岸带开发中的重大挑战。以福建省汀江长汀县段为研究对象,引用河流景观尺度理论,从生态安全视角分析县域尺度下的生态敏感性与灾害风险性,构建生态安全格局;在河段尺度下,根据不同功能下的河岸带宽度要求,建立50 m、150 m、500 m多环缓冲区,并结合生态安全格局划分不同缓冲区的河岸带功能,提出优化措施,为维护汀江流域的生态安全提供科学依据,为促进山地区域及其河岸带的可持续发展规划提供参考。

多元视野下的海南省临高县海岸带综合评估与深度空间管控探讨

为进一步加强海岸带综合管理,探索更有效的空间管控方法,从各类生态环境敏感性的形成机理出发,通过选取代表性评价指标构建评价模型,综合评估了海南省临高县海岸带生态环境敏感性和地质灾害风险性,并将其与国土规划相结合,对研究区进行了深度空间管控分区分析。结果表明:1)土地荒漠化、土地盐渍化、暴雨洪涝、赤潮、海岸侵蚀均以轻度敏感为主,土壤侵蚀、台风灾害以中度敏感为主,特殊生境、风暴潮和灾害性海浪以高度敏感为主。综合敏感性轻度、中度、高度与极度敏感区面积分别为10651.28、9682.11、3275.29和983.88 hm^2,其中高度敏感区以调楼镇分布面积最大,极度敏感区以博厚镇分布最广;2)地质灾害以地震、崩塌、滑坡、地面沉降、砂土液化为主,除地震风险分为风险大区与中等区外,其余4种均只有中等风险区和风险小区,综合风险则有大、中等和小3个分级,其中风险大区主要分布于博厚、东英、波莲与皇桐镇的断裂带两侧各15 m范围区内,总面积为118.86 hm2;3)集生态敏感性、地质灾害风险与国土规划多元视野的海岸带深度空间管控分区,可较好地识别重要保护对象与关键保护区域,并使海岸带获得充分开发与利用。

Risk assessment of water inrush in tunnels based on attribute interval recognition theory

Water inrush is one of the most serious geological hazards in underground engineering construction.In order to effectively prevent and control the occurrence of water inrush,a new attribute interval recognition theory and method is proposed to systematically evaluate the risk of water inrush in karst tunnels.Its innovation mainly includes that the value of evaluation index is an interval rather than a certain value;the single-index attribute evaluation model is improved non-linearly based on the idea of normal distribution;the synthetic attribute interval analysis method based on improved intuitionistic fuzzy theory is proposed.The TFN-AHP method is proposed to analyze the weight of evaluation index.By analyzing geological factors and engineering factors in tunnel zone,a multi-grade hierarchical index system for tunnel water inrush risk assessment is established.The proposed method is applied to ventilation incline of Xiakou tunnel,and its rationality and practicability is verified by comparison with field situation and evaluation results of other methods.In addition,the results evaluated by this method,which considers that water inrush is a complex non-linear system and the geological conditions have spatial variability,are more accurate and reliable.And it has good applicability in solving the problem of certain and uncertain problem.

Measuring Social Vulnerability to Natural Hazards in Beijing-Tianjin-Hebei Region,China

Social vulnerability in this study represents the differences between the capacity to cope with natural hazards and disaster losses suffered within and between places.The assessment of social vulnerability has been recognized as a critical step in understanding natural hazard risks and enhancing effective response capabilities.This article presents an initial study of the social vulnerability of the Beijing-Tianjin-Hebei(B-T-H) Region in China.The goal is to replicate and test the applicability of the United States Social Vulnerability Index(So VI) method in a Chinese cultural context.Thirty-nine variables adapted from the So VI were collected in relation to two aspects:socioeconomic vulnerability and built environment vulnerability.Using factor analysis,seven factors were extracted from the variable set:the structure of social development,the level of economic and government financial strength,social justice and poverty,family structure,the intensity of space development,the status of residential housing and transportation,and building structure.Factor scores were summed to get the final So VI scores and the most and least vulnerable units were identified and mapped.The highest social vulnerability is concentrated in the northwest of the study area.The least socially vulnerable areas are mainly distributed in the Beijing,Tianjin and Shijiazhuang core urban peripheral and central city areas of the prefecture-level cities.The results show that this method is a useful tool for revealing places that have a high level of vulnerability,in other words,areas which are more likely to face significant challenges in coping with a large-scale event.These findings could provide a scientific basis for policy making and the implementation of disaster prevention and mitigation in China.

Hazard and population vulnerability analysis: a step towards landslide risk assessment

In this paper, an attempt to analyse landslide hazard and vulnerability in the municipality of Pahuatlfin, Puebla, Mexico, is presented. In order to estimate landslide hazard, the susceptibility, magnitude （area-velocity ratio） and landslide frequency of the area of interest were produced based on information derived from a geomorphological landslide inventory; the latter was generated by using very high resolution satellite stereo pairs along with information derived from other sources （Google Earth, aerial photographs and historical information）. Estimations of landslide susceptibility were determined by combining four statistical techniques： （i） logistic regression, （ii） quadratic discriminant analysis, （iii） linear discriminant analysis, and （iv） neuronal networks. A Digital Elevation Model （DEM） of lo m spatial resolution was used to extract the slope angle, aspect, curvature, elevation and relief. These factors, in addition to land cover, lithology anddistance to faults, were used as explanatory variables for the susceptibility models. Additionally, a Poisson model was used to estimate landslide temporal frequency, at the same time as landslide magnitude was obtained by using the relationship between landslide area and the velocity of movements. Then, due to the complexity of evaluating it, vulnerability of population was analysed by applying the Spatial Approach to Vulnerability Assessment （SAVE） model which considered levels of exposure, sensitivity and lack of resilience. Results were expressed on maps on which different spatial patterns of levels of landslide hazard and vulnerability were found for the inhabited areas. It is noteworthy that the lack of optimal methodologies to estimate and quantify vulnerability is more notorious than that of hazard assessments. Consequently, levels of uncertainty linked to landslide risk assessment remain a challenge to be addressed.

Flood Vulnerability Assessment： A Multiscale, Multitemporal and Multidisciplinary Approach

Recent catastrophic events related to floods in Colombia reveal again the situation of disaster as a development issue not solved in the country. It is necessary to analyze in more detail the areas under threat and their respective vulnerability to the different mechanisms can generate flooding events and make adjustments in the assessment of disaster risks for the appropriate decision-making at local, regional and national levels. This paper presents a research project in its first phase, whose main objective is to develop a methodology for vulnerability assessment from a multiscale, multitemporal and multidisciplinary perspectives, combining the use of indicators and a spatial information system to analyze exposure and vulnerability at regional and local level in specific areas. This methodological tool will also enable local and regional authorities to identify the most appropriate strategies to reduce vulnerability and adaptation options, and make better decisions in assessing disaster risk. The information generated in this study will contribute to public policy action structured to correct short- and medium-term situations of actual or potential vulnerability, which can also be used in other activities of territorial and environmental planning, developing technology transfer activities and training associated with the research project in the service of the authorities and communities. Results obtained of the vulnerability analysis for a Colombian study area will relate to the hazards obtained in a parallel project whose goal is to identify the best risk management strategies through the development of GIS （geographic information system）-based scenarios for different risk and vulnerability reduction options.

Building Vulnerability Evaluation in Landslide Deformation Phase

Building vulnerability evaluation is important in the risk assessment on earthquake and flood hazards. But for landslide hazard, it is also a very important part for the people in buildings. Most discussions or researches about building vulnerability are for landslide failure, few for landslide in deformation phase. For this objective, this paper discussed about building vulnerability evaluation using Zhaoshuling landslide as an example Zhaoshuling landslide named located in the Three Gorges Reservoir Area, China. After a field survey on the geological condition of landslide, detailed field investigation on the buildings' location and structure is carried out. To get landslide surface deformation, numerical simulation method is used under the combining condition of water fluctuation and rainfall. Then building deformation and probable damage degree is analyzed according to landslide surface deformation and the relative theory in mining. Based on the national standard building damage classification system, the vulnerability of all the buildings on the landslide is semi-quantitatively evaluated.

Quantitative Assessment and Spatial Characteristics of Agricultural Drought Risk in the Jinghe Watershed, Northwestern China

Though drought is a recurrent phenomenon in the Jinghe watershed, very little attention has been paid to drought mitigation and preparedness. This article presents a method for the spatial assessment of agricultural drought risk in the Jinghe watershed of western China at a 1-km grid scale. A conceptual framework, which emphasizes the combined roles of hazard and vulnerability in defining risk, is used. The Z index method in a GIS environment is used to map the spatial extent of drought hazards. The key social and physical factors that define agricultural drought in the context of the Jinghe watershed are indentified and corresponding thematic maps are prepared. Risk is calculated by the integration of hazard and vulnerability. Results show that the risk gradient follows a north-south and west-east tendency and that agricultural droughts pose the highest risk to northern and northwestern sections of the Jinghe watershed.

Assessment of Economic Damage Risks from Typhoon Disasters in Guangdong, China

Guangdong is a developed province in China, but suffers from frequent typhoon disasters which cause great economic loss. Quantitative regional risk assessment of typhoon disasters is important for disaster prevention and mitigation. According to direct economic loss and typhoon intensity information, we established a typhoon disaster loss rate curve using data from 1954 to 2008. Based on GIS spatial module, the economic vulnerabilities of different intensity typhoons were calculated for 98 counties in Guangdong Province. Different intensity typhoon landing frequencies in Guangdong were also calculated, and used to indicate typhoon disaster probability. A risk assessment model was established to assess economic loss risk under different intensity typhoons in Guangdong. The results show that economic loss risk caused by typhoon is more than 10 thousand million CNY; according to typhoon intensity grade, economic risk is up to 10.467, 14.429, 7.753 and 13.591 thousand million CNY for slight, light, medium and severe typhoons, respectively. The Pearl River Delta is the highest risk region, especially Guangzhou, Dongguan, Shenzhen, Zhongshan and Zhuhai. Risk value decreases from Pearl River coastal outfall to the inland in a radial pattern. Inland areas far from coastal counties have lower risk, and the risk value is less than 50 million CNY. When typhoon intensity increases from slight to medium, the risk in western is higher than in eastern parts, but when typhoons become to severe, the risk value in eastern Guangdong part is higher than in the west.

Integrated risk assessment of complex disaster system based on a non-linear information dynamics model

This paper describes a non-linear information dynamics model for integrated risk assessment of complex disaster system from an evolution perspective. According to the occurrence and evolution of natural disaster system with complicated and nonlinear characteristics, a non-linear information dynamics mode is introduced based on the maximum flux principle during modeling process to study the integrated risk assessment of complex disaster system. Based on the non-equilibrium statistical mechanics method, a stochastic evolution equation of this system is established. The integrated risk assessment of complex disaster system can be achieved by giving reasonable weights of each evaluation index to stabilize the system. The new model reveals the formation pattern of risk grade and the dynamics law of evolution. Meanwhile, a method is developed to solve the dynamics evolution equations of complex system through the self-organization feature map algorithm. The proposed method has been used in complex disaster integrated risk assessment for 31 provinces, cities and autonomous regions in China mainland. The results have indicated that the model is objective and effective.