Landfill gas - a potential environmental hazard

Methane derived from the decomposition of organic material contained within a landfill may escape beyond the site boundary where it can pose an explosion or fire hazard. Methods are described to prevent die occurrence of such lateral gas migration. Problems due to the accumulation of gas in buildings, erected on landfill sites, have occurred and techniques are now available to overcome these at some sites. However, it is recognized that at other sites, redevelopment should not be allowed to take place on die grounds of safety.     

Climate change as a major slow-onset hazard to development: an integrated approach to bridge the policy gap

The paper considers climate change from a hazard to economic development and public security perspective. Integration of climate change adaptation and disaster risk reduction policies is substantiated, building upon resilience concept as a unique methodological basis and civil protection measures as a common practice. Specific recommendations to implement this integration are introduced.     

永定河下游土地覆盖变化及其驱动力分析

以1978年的黑白航片和2008年的彩红外航片为数据源,对永定河下游流域30年来的土地覆盖变化进行了分析。20世纪70年代的航拍数据是全色黑白航空摄影像片,需要对扫描的黑白航片进行匀色处理,然后对匀色处理后的黑白航片及彩红外航片进行排列,镶嵌,配准纠正等数据预处理工作。采用面向对象的分类方法提取永定河下游的土地覆盖类型,并结合专家经验,采用人工判读的方法,对提取结果进行验证。根据永定河下游1978-2008年土地覆盖类型的数量变化特征,说明30年来,耕地、人工湿地、草地和未利用地的面积呈现增大的趋势,其中未利用地面积增大得最快,单一动态度高达218%。自然湿地和林地的面积则呈减少的趋势,自然湿地面积减少的幅度较为明显。利用转移矩阵对永定河下游土地覆盖类型之间的相互转化进行分析表明,主要是自然湿地向耕地和未利用地的转化;耕地和林地之间的相互转化,以及耕地向未利用地的转化。综上分析,自然湿地成为最大的转出源。影响永定河下游土地覆盖变化的驱动力因子分为自然因素和人为因素两种。     

西藏沙漠化灾害现状及其驱动力研究

西藏自治区是我国沙漠化灾害问题较为严重的地区之一,有沙漠化灾害土地19．974万km^2占全区土地总面积的16．58％,包括重度、中度、轻度3级和流动沙（丘）地、半固定沙（丘）地、固定沙（丘）地、裸露沙砾地、半裸露沙砾地5类沙漠化灾害土地,其中以中度沙漠化灾害土地和裸露沙砾地类沙漠化灾害土地为最多。沙漠化灾害将使区内生态环境与生存条件恶化,破坏建设工程,直接影响农业生产,导致人民生活贫困,并构成严重的潜在压力,造成了巨大的经济损失,平均年经济损失高达34．5亿元。驱动力分析表明,西藏的土地沙漠化灾害是在近期“全球变化”背景下气候干暖化和人为的过度经济活动共同促成的。     

我国泥石流危险度评价研究:回顾与展望

综述了自20世纪80年代末我国开展泥石流危险度评价研究以来,4个主要不同时期所用的评价方法及其发展过程,介绍了最新的单沟泥石流危险度评价技术及其改进的评价因子转换函数赋值新方法。首次提出了泥石流危险度评价的理论公式及其数值解,同时也指出了泥石流危险度理论研究方面所面临的困难。目前,现有的泥石流危险度评价方法是有效的和实用的,进一步的工作宜放在评价方法的可靠性研究上,同时要大力开展泥石流规模和发生频率相互关系的研究,以期达到最终用理论公式来评价泥石流危险度的目的,并实现现状评价和预测评价能同时进行的目标。     

丹巴县地质灾害发育特征及成因探讨

在对丹巴县地质灾害进行详细调查的基础上,结合该县近年来地质灾害的发育情况,对丹巴县地质灾害的发育特征和形成原因进行了简要的分析。研究表明,该县地质灾害具有爆发频率高、突发性强、危害大、隐蔽性强的特点,其分布发育与区内独特的自然地理格局和复杂的地质环境条件密切相关,且近年来该县地质灾害的爆发处在一个活跃期。     

论天然气水合物与海底地质灾害、气象灾害和生物灾害的关系

论述了天然气水合物与海底滑坡、全球变暖和海底生物灭绝等地质、气象、生物灾害的关系。海底天然气水合物的分解能够减小沉积物的胶结强度,并导致沉积层孔隙压力的过剩,进而诱发海底滑坡的发生。天然气水合物与全球变暖关系密切。从天然气水合物释放出来的甲烷可使地球温度升高4℃至8℃,升温的结果一方面可能中和全球变冷的趋势,另一方面也可能加剧全球变暖的趋势。全球天然气水合物大规模的分解,导致了海底单细胞生物大量灭亡,对海底生物多样性的保持构成巨大危害。在天然气水合物开发利用的设计阶段和实施阶段,必须有足够的防范意识和技术措施,防止或尽可能减少天然气水合物开发利用造成的各种环境灾害。     

Gas bursts from cameroon crater lakes: a new natural hazard

Gas bursts from tropical crater lakes constitute a hitherto unrecognized natural hazard, which claimed 37 lives around Lake Monoun in 1984 and 1,746 lives in 1986 around Lake Nyos in Cameroon, west Africa. Studies of these events indicate that the lethal gas clouds were dominantly CO(2) which exsolved catastrophically from deep waters of the lakes, producing in the case of Lake Nyos a gas cloud of 1.94 times 10(6) tons CO(2) . Carbon-isotope data indicate a magmatic source of the carbon dioxide, but the geochemistry of deep water and gases does not support a sudden injection of volcanic gas from a deep source into the lakes. Rather, it is proposed that the gas bursts were preceded by gradual build-up of dissolved bicarbonate in deep waters, where anoxic conditions in enclosed and stagnant basins led to low pH and pCO(2) close to saturation. Steady input from the Earth's mantle to submerged mofettes or CO(2) -rich soda springs within the lakes is most likely the primary source of carbon dioxide. Lethal effects of the gas bursts are almost entirely due to CO(2) -induced asphyxia. A small percentage of victims awoke from coma one or two days after the event, but most died. Unusual skin lesions on about 5% of victims arose from the comatose state. It is shown that the mass of gas required to account for the lethal effects and observed gas clouds is an order of magnitude less than the potential gas yield from the lakes. In view of the lethal gas bursts from the small Cameroon lakes, the potential hazard of future gas bursts from other much larger density-stratified equatorial lakes must be seriously considered, particularly in Lake Kivu in east Africa, where methane and carbon dioxide gas content is higher by two to four orders of magnitude than that of the Cameroon lakes. A gas burst from Lake Kivu would form a carbon dioxide cloud up to 340 km(3) in volume and expansion of the exsolving gas from deep water to atmospheric pressure would correspond to an energy release equivalent to 8 megatons of explosive.     

Post-conflict health reconstruction: search for a policy

Despite increasing experience in health reconstruction in societies emerging from conflict, the policy basis for investing in the development of equitable and effective health systems in the wake of war remains unsettled. Consideration of post-conflict health reconstruction is almost entirely absent in donor policies on global health. Practically by default, health programmes are seen increasingly as an element of stabilisation and security interventions in the aftermath of armed conflict. That perspective, however, lacks an evidence base and can skew health programmes towards short-term security and stabilisation goals that have a marginal impact and violate the principles of equity, non-discrimination, and quality, which are central to sound health systems and public acceptance of them. A better approach is to ground policy in legitimacy, viewing health both as a core social institution and one that, if developed according to human rights principles, including equity, non-discrimination, participation and accountability, can advance the effectiveness and the quality of governance in the emerging state.     

Improving flood warnings in Europe: a research and policy agenda

Abstract

Warnings and emergency planning for flooding are based on the reality that no matter how thorough our investigations and flood prevention efforts through engineered structural works or land use management, some risk will always remain. This paper examines recent experience with flood warnings in the UK and continental Europe. It combines this experience with an overview of the relevant literature to identify lessons for incorporation into policy, and problem areas which would most obviously benefit from additional research. Throughout, the emphasis is on the non-engineering aspects of warning systems. Results indicate that much is being achieved in terms of the detail of warning design, but the broader issues seem to be largely ignored by both the research literature and practice. First among these broader issues is the failure, by those charged with warning system development and operation, to conceptualise the warning task as one based explicitly on the needs of those at risk. Making this happen will require the development of processes to build the necessary culture of cooperation and learning among the many organisations involved.     

Unauthorised development and seismic hazard vulnerability: a study of squatters and engineers in Istanbul, Turkey

Many cities in developing nations have experienced an influx of poor migrants in search of work. This population influx has often been accommodated through land squatting, irregular construction and unauthorised housing. For the urban poor, this has resulted in immediate affordable housing; however, this housing frequently has long-term vulnerability to natural hazards. This article examines the ways in which squatters in Istanbul, Turkey, understand the seismic vulnerability of their unauthorised housing. Distrust of professional engineers and contractors has led Istanbul squatters to believe that self-built housing will not only be less costly but also safer than commercially built housing. The impact of residents' risk perceptions on their vulnerability to natural hazards is examined through a comparison of social attitudes regarding safe housing and the quality of unauthorised construction. This comparison highlights how squatters' risk perceptions necessitate innovative means of reducing vulnerability in unauthorised neighbourhoods of developing cities.     

Internal communication a prerequisite for risk governance: hazard zone planning in South Tyrol,Italy

Mountain risk management is currently facing a scientifically driven, normative paradigm change towards risk governance, where communication and participation take on key roles. On the local level, hazard zone planning is a risk management tool to balance land-use developments and hazard processes, such as debris flows, avalanches, rock fall, mass movements or flooding. In this contribution, communication among stakeholders professionally involved in hazard zone planning (internal communication) is analysed by participant observation. Here, the quality of internal communication is seen both as an indicator and as a prerequisite for transition processes from risk management to risk governance. This case study of communication in hazard zone planning in the Autonomous Province of South Tyrol points out pitfalls and challenges in an advanced, spatial planning scheme. Based on the concept of social learning, it is argued that the transition towards governance of mountain risks requires fundamental changes in the underlying normative models, objectives, organizational understandings, structures and qualifications of the administrative bodies. Proposals for change are provided.     

家户水灾社会脆弱性的评估方法研究——以长沙地区为例

中国是洪水灾害发生频繁的国家之一，研究水灾脆弱性对中国的灾害风险管理有着极为重要的意义。但是，合理评估脆弱性尤其是社会脆弱性却面临着极大的挑战。利用Hoovering改进模式，选择湘江流域的长沙地区为研究区，对研究区内的家户进行了社会脆弱性评价。结果表明，长沙市区的5个区内，高脆弱性家户最多的是天心区，最少的是雨花区。而就社区而言，高脆弱性家户最多的足裕南街街道和桔子洲街道。该结果反映了长沙不同行政区、社区社会脆弱性的差别，可供确定受援地区和受援人群及开展援助活动，乃至灾后日常风险管理参考。     

Communities and bushfire hazard in Australia: More questions than answers

The issue of communities and their exposure to bushfire hazard is highly topical internationally. There is a perceived trend of greater exposure to bushfire risk which is exacerbated by increased levels of building in fire-prone areas or peri-urban regions. There is a need to clarify what we understand to be peri-urban regions, and how we conceptualise and describe the communities that reside in them, in order that efficient and effective services are provided. However, more questions arise for us. For example: Where are these communities located? What do we know about the people who live there? What are the implications for bushfire mitigation? Despite being problematic, locality remains important to the understanding of communities, bushfire hazard and delivery of services.     

Reducing hazard vulnerability: towards a common approach between disaster risk reduction and climate adaptation

Over the past few decades, four distinct and largely independent research and policy communities--disaster risk reduction, climate change adaptation, environmental management and poverty reduction--have been actively engaged in reducing socio-economic vulnerability to natural hazards. However, despite the significant efforts of these communities, the vulnerability of many individuals and communities to natural hazards continues to increase considerably. In particular, it is hydro-meteorological hazards that affect an increasing number of people and cause increasingly large economic losses. Arising from the realisation that these four communities have been largely working in isolation and enjoyed only limited success in reducing vulnerability, there is an emerging perceived need to strengthen significantly collaboration and to facilitate learning and information exchange between them. This article examines key communalities and differences between the climate change adaptation and disaster risk reduction communities, and proposes three exercises that would help to structure a multi-community dialogue and learning process.     

The hazard of forest fires in southern France

The annual hazard of fire in the forest, maquis and garrigue of southern France is related both to the fragile nature of the Mediterranean ecosystem and to man's activities. The Mediterranean vegetation is adapted to withstand the aridity of the summer months, but the combination of high temperatures, low precipitation, critical soil-moisture levels and occasional bouts of strong winds (mistral) desiccate the vegetation cover and create conditions in which outbreaks of forest fires are inevitable. Although the annual incidence and impact of forest fires are related to the occurrence of extreme weather conditions they are also exacerbated by depopulation of the remoter rural areas, the spread of urbanization and the growth of tourist facilities in the more accessible coastal zones, and above dl by man's carelessness. This article reviews the factors affecting the nature and severity of forest fires and discusses the attempts being made to prevent and control forest fires in the Mediterranean zone of southern France     

基于GIS的沐川县滑坡危险度区划

基于GIS技术及统计方法,对沐川县滑坡进行了区划研究.从与滑坡发育相关的因子中提取了5个本底因子:地层、坡度、坡形、高差和坡向,以此反演计算了研究区环境本底因子对滑坡的贡献和本底因子的权重.采用贡献率权重叠加法对研究区进行危险度区划,其中高危险度区114.7km2,中危险度区229.9km2,低危险度区100.9km2.经与野外调查结果对比检验,区划可靠性达到90%以上.     

基于数值模拟的台风危险性分析综述(Ⅰ)——台风风场模型

台风风场是基于数值模拟的台风危险性分析的重要组成部分。基于现有文献资料,以台风风场内空气微团的运动平衡方程为出发点,对现有的基于平衡运动方程的参数化风场模型进行了评述,并建议选用CE风场;回顾了对风场预测结果有重要影响的两个输入参数的信息获得途径,重点就国内台风区城市应该如何处理这两个参数提出了建议;然后从台风边界层的物理意义出发,评述了现有的边界层模型,建议采用Thompson和Cardone所提的具有物理意义的边界层模型;最后对今后工程风场的发展方向提出了一些看法。尽管从气象学角度来看,三维风场是精度很高的模型,但是其工程实用性还有待考证;在满足工程精度的前提下,简单易行的模型是目前进行台风危险性分析的风场数值模拟的较好选择。