对地质灾害易发性危险性易损性和风险性的探讨

论述了地质灾害易发性、危险性、易损性和风险性的基本概念。易发性是对某一地区地质灾害发生难易程度的描述,反映物理地质现象;危险性是灾害规模和发生概率的函数,反映灾害的活动程度和破坏能力;易损性表明社会经济易损程度及人类社会应对灾害的能力;风险性是灾害自然属性和社会经济属性的结合统一体,表达为危险性和易损性的乘积。在此基础上阐述了其影响因素和计算方法。认为这种由浅入深、由表及里的思路可应用于地质灾害评价研究及风险管理当中,具有较好的发展前景。     

河北省海岸系统脆弱性评价

为探讨海岸系统脆弱性评价方法,根据系统性、客观性、可操做性、主导性原则,采用基于GIS的层次分析方法,选取风暴潮影响频率、相对海平面变化率、海岸类型、海岸侵蚀堆积率、区域海岸水下岸坡度、地面沉降率、海岸开发类型、近海水质8种评价因子,对河北省海岸系统脆弱性进行了评价。采用的评价方法比较成熟,选取的评价因子符合评价区的实际情况。     

Gender,ethnicity and vulnerability to climate change: The case of matrilineal and patrilineal societies in Bamenda Highlands Region,Cameroon

Intersectionality is gaining credence in explaining the complexities in rural women’s vulnerability to the impacts of climate change. This study is framed on the assumption that rural women are likely to be affected differently by climate change due to cultural differences. The life history approach was utilised to conduct empirical research in the Bamenda Highlands Region, Cameroon on ethnicity and differential effects of climate change among female farmers in the communities of Kom and Oku representing a matrilineal and patrilineal communities respectively. The research found that single and married women in both matrilineal and patrilineal societies experienced similar patterns of vulnerability relating to socio-economic and cultural discrimination stemming from patriarchal dominance. However, the study also highlighted that contrary to other communities women are not more economically empowered under matrilineal systems than their counterparts in patrilineal societies. In contrast, widows in patrilineal societies were found to have more autonomy in the control of land and other resources than those in matrilineal societies. The study contributes to growing interest in the cultural dimensions of vulnerability to climate change and recommends the inclusion of cultural perspectives in the design and implementation of adaption policies, programs and actions.     

An assessment of the risk associated with urban development in the Thiaroye area (Senegal)

Water quality data from 56 wells, aquifer characteristics, soil types and land use in the city suburb of Dakar were compared to assess the effects of land use on the Thiaroye groundwater quality. The study area encompassed an unsewered densely populated zone, agricultural land, low density villages, and undeveloped land located in the sand dunes. A method similar to GIS technologies was applied to evaluate the degree of vulnerability of the different parts of the aquifer in relation to urban development, land use and aquifer characteristics. The aquifer parameters (hydraulic conductivity, groundwater level depth, recharge, soil type) were re-evaluated qualitatively into three class rankings (high, moderate and low), depending on the likelihood for contaminants reaching the water table, then combined using the two matrix Boolean logic based approaches to identify the nine classes of vulnerability assessed in the aquifer domain. An attempt was made to explain the distribution of nitrate concentration with the assessed vulnerability. In the area assessed, in the densely populated zone running from Pikine, to Thiaroye and Yeumbeul, very high nitrate concentrations correspond with the highest vulnerability index (H1). Nitrate contamination in this area is a consequence of point-source seepage from individual septic systems improperly built in this area. In the eastern part of the aquifer, high nitrate concentrations at Deni B. Ndao, Mbawane and Golam localities coincide with a moderate vulnerability assessment. The major source of nitrate in these areas is induced by agricultural activities.     

Vulnerability evaluation of a coastal plain sand aquifer with a case example from Calabar,southeastern Nigeria

A point count index method using a well drillers log and field measurements has been developed following the DRASTIC and SINTACS procedures to map and evaluate the vulnerability of a coastal plain aquifer to surface and near surface contamination. The input parameters with the acronym CALOD include clay layer thickness (C), aquifer media character (A), lateritic layer thickness (L), overlying layer character (O) and the depth to groundwater level (D). The CALOD vulnerability potential index (CALOD index) is computed as the sum of the products of weights and ratings assigned to each of the input parameters. The CALOD index, varying between 15 and 75, is divided into four classes: high (>60), high-medium, (40–60), low-medium (20–40) and low (<20). The CALOD index is then used to produce a vulnerability potential map for the area. From the map, areas of high, high-medium and medium-low are consistent with the upper gravelly aquiferous zone while areas of medium-low and low are restricted to the deeper lower sandy aquiferous layer. The most important parameters affecting groundwater vulnerability to pollution in coastal areas include saturated thickness of the aquifer, depth to groundwater level, lateritic layer thickness and the aquifer media character. The concentration of some chemical pollution indicators (electrical conductivity, K, NO₃, Cl and metal load) are relatively higher for the highly vulnerable shallower upper gravelly unit in comparison to the less vulnerable deeper sandy unit. This method is very suitable for coastal plain sand aquifers especially, where data is scare.     

Future impacts of drivers of change on wetland ecosystem services in Colombia

Wetlands are among the most valuable ecosystems in the world due to their delivery of ecosystem services (ES), but they are particularly vulnerable to drivers of land-use change. However, little is known about how different wetlands respond to drivers of land-use change and how that impacts their delivery of ES. After extreme floods hit Colombia in 2010–2011, negative impacts from these storms heightened the interest of Colombian policy-makers in understanding and recognizing the importance of wetlands. Here, we present a map with 19 wetland types for Colombia and assess the ES that these wetlands deliver and how those ES are impacted by drivers of land-use change. We based our spatial analysis on the Corine Land Cover data for Colombia and combined that with spatial indices derived from knowledgeable experts using the matrix approach and participatory mapping (PGIS). The most vulnerable wetland types identified were floodplain forests, riparian wetlands, freshwater lakes and rivers. The region of Magdalena-Cauca has been identified as the most vulnerable to the impacts of land-use change, until 2025. We discuss our results in light of the current Colombian policy-debate which concerns the designation of wetlands as strategic ecosystems. This designation implies necessary restrictions or prohibition of harmful activities in wetlands, principally mining and industrial agriculture.     

Quantitative Risk Assessment of Catastrophic Debris Flows through Numerical Simulation

The risk assessment is not only the one of the most effective soft measures in natural hazard prevention, but also is the base of hazard risk management. On account of the specificity of various elements at risk and debris flow mechanism, the theoretical system and technical procedure of debris flow quantitative risk assessment for buildings and roads were established in the mountaineous area of Southwest China, which included three sections: ①To represent debris flow hazard quantitatively using the intensity index IDF through FLO-2D simulation; ②To build debris flow physical vulnerability curve based on the loss exceedance-probability from Qipan gully debris flow case; ③To quantify the expected loss of the important elements at risk based on their database after setting the future debris flow scenarios. The case study of Yangling catchment indicated that the responding mechanism between elements at risk and debris flow physical mechanism was described quantitatively by this quantitative risk assessment system, which can contribute to the construction planning and prevention measure making in the southwestern mountainous area.     

Comparative Analysis of Risk Assessment of Landslides and Debris Flows of China in 2000 and 2010

Landslides and debris flows occurr in China frequently and cause disastrous losses of life and property. The risk assessment of landslides and debris flows and their spatial variations were comparatively analyzed in this paper, which has great significance for disaster prevention. This article selected 1 km×1 km grid as the assessment unit and with support of GIS technique, analyzed landslide and debris-flow risk distribution and their spatial variations from 2000 to 2010. The research results indicated that the spatial distribution of risk classes in 2000 and 2010 was obviously discrepant. Overall, taking the Heihe-Tengchong population density line as the boundary, the west of the line is mainly low risk area; the east of the line is mainly high risk area. Compared with the risk of 2000, the risk values of 2010 increased, with the high risk area and low risk area enlarged, moderate risk area reduced. The moderate risk area is the most unstable and sensitive risk area, and its risk class variation is significant. However, China is not a region with the high risk of landslide and debris-flow hazard at present. In the following next 10 years, the risk of landslides and debris flows in China will continue to increase.     

Large-scale vulnerability assessments for natural hazards

This article examines the process by which vulnerability analysis takes place at the state level for State Hazard Mitigation Plans, as required by the Disaster Mitigation Act of 2000. The methods developed by the Center for Hazards Research and Policy Development at the University of Louisville are described, followed by a brief discussion on issues and challenges. A key finding in this article is the need to understand the impact and role of vulnerability analysis on planning and policy-making at the state and local level, as it applies to the investment of funding and resources in hazard mitigation. Recommendations for policy as well as directions in future research are offered in conclusion.     

The extent of saltwater intrusion in southern Baldwin County,Alabama

Sea level rise (SLR) as a result of global warming has an impact on the increasing inundation on the coastal area. Nowadays, Semarang coastal area in Indonesia is already subject to coastal hazard due to tidal inundation and land subsidence. The impact of the inundation is predicted to be even more severe with the scenario of sea level rise. This paper concentrates on the risk assessment to the population, land use, and monetary losses as a result of coastal inundation under enhanced sea level rise. This paper uses the scenario of the depth of inundation to generate coastal inundation model using GIS-Technology. Anticipatory issues including methodology development for hazard assessment would be necessary for Semarang coastal area, and therefore, geo-information technology can be considered as a useful tool to rapidly assess the impact of the coastal hazard and evaluate the economic losses.