Mountain hazards: reducing vulnerability by adapted building design

Despite the long tradition of technical mitigation on a catchment scale in European mountain regions, losses due to mountain hazards are still considerably high in number and monetary loss. Therefore, the concept of technical mitigation had been supplemented by land-use planning and, more recently, local structural protection. Local structural protection includes measures directly implemented at or adjacent to endangered objects, and has proven to be particularly cost-effective with respect to integral risk management strategies. However, the effect of local structural protection in reducing the vulnerability of elements at risk, and the associated consequences with respect to a reduction of structural vulnerability have not been quantified so far. Moreover, there is a particular gap in quantifying the expenditures necessary for local structural protection measures. Therefore, a prototype of residential building adapted to mountain hazards is presented in this study. This prototype is equipped with various constructional elements to resist the incurring impact forces, i.e., of fluvial sediment transport and of snow avalanches. According to possible design loads emerging from these hazard processes, the constructive design necessary is presented, and the amount of additional costs required for such an adaptation is presented. By comparing these costs with quantitative loss data it is shown that adapted building design is particularly effective to reduce the consequences of low-magnitude, high-frequency events in mountain regions.     

Assessing landslide exposure in areas with limited landslide information

Landslide risk assessment is often a difficult task due to the lack of temporal data on landslides and triggering events (frequency), run-out distance, landslide magnitude and vulnerability. The probability of occurrence of landslides is often very difficult to predict, as well as the expected magnitude of events, due to the limited data availability on past landslide activity. In this paper, a qualitative procedure for assessing the exposure of elements at risk is presented for an area of the Apulia region (Italy) where no temporal information on landslide occurrence is available. Given these limitations in data availability, it was not possible to produce a reliable landslide hazard map and, consequently, a risk map. The qualitative analysis was carried out using the spatial multi-criteria evaluation method in a global information system. A landslide susceptibility composite index map and four asset index maps (physical, social, economic and environmental) were generated separately through a hierarchical procedure of standardising and weighting. The four asset index maps were combined in order to obtain a qualitative weighted assets map, which, combined with the landslide susceptibility composite index map, has provided the final qualitative landslide exposure map. The resulting map represents the spatial distribution of the exposure level in the study area; this information could be used in a preliminary stage of regional planning. In order to demonstrate how such an exposure map could be used in a basic risk assessment, a quantification of the economic losses at municipal level was carried out, and the temporal probability of landslides was estimated, on the basis of the expert knowledge. Although the proposed methodology for the exposure assessment did not consider the landslide run-out and vulnerability quantification, the results obtained allow to rank the municipalities in terms of increasing exposure and risk level and, consequently, to identify the priorities for designing appropriate landslide risk mitigation plans.     

Integrating spatial, temporal, and magnitude probabilities for medium-scale landslide risk analysis in Darjeeling Himalayas, India

Landslide risk assessment is based on spatially integrating landslide hazard with exposed elements-at-risk to determine their vulnerability and to express the expected direct and indirect losses. There are three components that are relevant for expressing landslide hazard: spatial, temporal, and magnitude probabilities. At a medium-scale analysis, this is often done by first deriving a landslide susceptibility map, and to determine the three types of probabilities on the basis of landslide inventories linked to particular triggering events. The determination of spatial, temporal, and magnitude probabilities depend mainly on the availability of sufficiently complete historical records of past landslides, which in general are rare in most countries (e.g., India, etc.). In this paper, we presented an approach to use available historical information on landslide inventories for landslide hazard and risk analysis on a medium scale (1:25,000) in a perennially typical data-scarce environment in Darjeeling Himalayas (India). We demonstrate how the incompleteness in the resulting landslide database influences the various components in the calculation of specific risk of elements-at-risk (e.g., buildings, population, roads, etc.). We incorporate the uncertainties involved in the risk estimation and illustrate the range of expected losses in the form of maximum and minimum loss curves. The study demonstrates that even in data-scarce environments, quantitative landslide risk assessment is a viable option, as long as the uncertainties involved are expressed.     

滑坡风险评估的难点和进展

近年来,国内外滑坡研究日益重视滑坡风险评估和管理技术方法的研究,但滑坡风险评估依然是存在很多问题和难点,尤其是在中等—大比例尺区域滑坡风险定量评估方面,主要表现在滑坡编录数据库建设、滑坡影响因素的识别和建模、滑坡时间、空间预测的不确定性,滑坡诱发因素动态变化的定量刻画,承灾体识别和易损性定量评价等方面。在阐述滑坡风险评估流程的基础上,围绕滑坡风险评估与制图中滑坡编录和基础数据获取与更新,危险性分析中的滑坡空间、时间概率和滑坡特征预测、损失评估中的易损性分析与定量和承灾体定量化制图等技术方法中的难点和存在的问题,概述针对这些问题所取得的研究进展,并指出了滑坡风险研究的技术发展趋势。     

A structured approach to enhance flood hazard assessment in mountain streams

An evidence-based flood hazard analysis in mountain streams requires the identification and the quantitative characterisation of multiple possible processes. These processes result from specific triggering mechanisms on the hillslopes (i.e. landslides, debris flows), in-channel morphodynamic processes associated with sudden bed changes and stochastic processes taking place at critical stream configurations (e.g. occlusion of bridges, failure of levees). From a hazard assessment perspective, such possible processes are related to considerable uncertainties underlying the hydrological cause-effect chains. Overcoming these uncertainties still remains a major challenge in hazard and risk assessment and represents a necessary condition for a reliable spatial representation of process intensities and the associated probabilities. As a result of an accurate analysis of the conceptual flaws present in the procedures currently employed for hazard mapping in South Tyrol (Italy) and Carinthia (Austria), we propose a structured approach as a means to enhance the integration of hillslope, morphodynamic and stochastic processes into conventional flood hazard prediction for mountain basins. To this aim, a functional distinction is introduced between prevailing one-dimensional and two-dimensional process propagation domains, i.e., between confined and semi- to unconfined stream segments. The former domains are mostly responsible for the generation of water, sediment and wood fluxes, and the latter are where flooding of inactive channel areas (i.e. alluvial fans, floodplains) can occur. For the 1D process propagation domain, we discuss how to carry out a process routing along the stream system and how to integrate numerical models output with expert judgement in order to derive consistent event scenarios, thus providing a consistent quantification of the input variables needed for the associated 2D domains. Within these latter domains, two main types of spatial sub-domains can be identified based on the predictability of their dynamics, i.e., stochastic and quasi-deterministic. Advantages and limitations offered by this methodology are finally discussed with respect to hazard and risk assessment in mountain basins.     

A review of assessing landslide frequency for hazard zoning purposes

The probability of occurrence is one of the key components of the risk equation. To assess this probability in landslide risk analysis, two different approaches have been traditionally used. In the first one, the occurrence of landslides is obtained by computing the probability of failure of a slope (or the reactivation of existing landslides). In the second one, which is the objective of this paper, the probability is obtained by means of the statistical analysis of past landslide events, specifically by the assessment of the past landslide frequency. In its turn, the temporal frequency of landslides may be determined based on the occurrence of landslides or from the recurrence of the landslide triggering events over a regional extent. Hazard assessment using frequency of landslides, which may be taken either individually or collectively, requires complete records of landslide events, which is difficult in some areas. Its main advantage is that it may be easily implemented for zoning. Frequency assessed from the recurrence of landslide triggers, does not require landslide series but it is necessary to establish reliable relations between the trigger, its magnitude and the occurrence of the landslides. The frequency of the landslide triggers can be directly used for landslide zoning. However, because it does not provide information on the spatial distribution of the potential landslides, it has to be combined with landslide susceptibility (spatial probability analysis) to perform landslide hazard zoning. Both the scale of work and availability of data affect the results of the landslide frequency and restrict the spatial resolution of frequency zoning as well. Magnitude–frequency relationships are fundamental elements for the quantitative assessment of both hazard and risk.     

Spatial scan statistics in vulnerability assessment: an application to mountain hazards

In the European Alps, the concept of risk has increasingly been applied in order to reduce the susceptibility of society to mountain hazards. Risk is defined as a function of the magnitude and frequency of a hazard process times consequences; the latter being quantified by the value of elements at risk exposed and their vulnerability. Vulnerability is defined by the degree of loss to a given element at risk resulting from the impact of a natural hazard. Recent empirical studies suggested a dependency of the degree of loss on the hazard impact, and respective vulnerability (or damage-loss) functions were developed. However, until now, only little information is available on the spatial characteristics of vulnerability on a local scale; considerable ranges in the loss ratio for medium process intensities only provide a hint that there might be mutual reasons for lower or higher loss rates. In this paper, we therefore focus on the spatial dimension of vulnerability by searching for spatial clusters in the damage ratio of elements at risk exposed. By using the software SaTScan, we applied an ordinal data model and a normal data model in order to detect spatial distribution patterns of five individual torrent events in Austria. For both models, we detected some significant clusters of high damage ratios, and consequently high vulnerability. Moreover, secondary clusters of high and low values were found. Based on our results, the assumption that lower process intensities result in lower damage ratios, and therefore in lower vulnerability, and vice versa, has to be partly rejected. The spatial distribution of vulnerability is not only dependent on the process intensities but also on the overall land use pattern and the individual constructive characteristics of the buildings exposed. Generally, we suggest the use of a normal data model for test sites exceeding a minimum of 30 elements at risk exposed. As such, the study enhanced our understanding of spatial vulnerability patterns on a local scale.     

Ore-Forming Processes and Dissipative Structures

The theory of dissipative structures is applied in this paper to probing into the dynamics, temporal struc-tures and spatial structures of ore-forming processes and the inherent relationships among them. Areas of oreformation are large dynamic systems in development and evolution. The core of ore formation is the "onset ofore-forming processes". and the crux of it is the "transition from mineralization to ore formation". The theoryof bifurcation and theory of fluctuation make possible the access to the solution of this problem. The multiord-er or successive bifurcation of dissipative structures introduces dynamic geochemical processes into geosciencesand inverses the dynamic evolution and temporal rhythms of ore-forming processes. The localization ofdissipative structures introduces dynamic geochemical fields into geosciences and brings to light the causes andmechanisms of the formation and development of geochemical areas of ore formation (regions and zones of oreformation) and their spatial dynamic patterns.     

二十世纪以来西南地区地质灾害研究历程与展望

西南地区发育有我国近30%的地质灾害隐患点,是我国地质灾害成因最复杂、数量最多、灾情最严重的地区之一,为更好地了解西南地区地质灾害研究历史和防灾减灾工作,本文在系统梳理西南地区地质灾害发育分布规律及危害特征现状基础上,简要回顾了二十世纪以来西南地区地质灾害研究的主要历程,并分三个主要阶段对所取得的进展和成效进行了总结。在此基础上,对未来西南地区地质灾害的主要研究趋势进行了展望,提出了西南地区地质灾害研究应重点关注高山极高山区高位远程地质灾害识别技术、特大地质灾害链形成机理与风险防控、基于地质灾害孕灾背景大数据智能挖掘的风险动态评价等,可供西南地区地质灾害研究与防治参考。     

Integration of statistical and heuristic approaches for landslide risk analysis: a case of volcanic mountains in West Java Province,Indonesia

Owing to fragile geo-morphology, extreme climatic conditions, and densely populated settlements and rapid development activities, West Java Province is the most landslide hazardous area in Indonesia. So, a landslide risk map for this province bears a great importance such as for land-use planning. It is however widely accepted that landslide risk analysis is often difficult because of the difficulties involved in landslide hazard assessment and estimation of consequences of future landslide events. For instance, lack of multi-temporal inventory map or records of triggering events is often a major problem in landslide hazard mapping. In this study, we propose a simple technique for converting a landslide susceptibility map into a landslide hazard map, which we have employed for landslide risk analysis in one ideally hazardous part of volcanic mountains in West Java Province. The susceptibility analysis was carried out through correlation between past landslides and eight spatial parameters related to instability, i.e. slope, aspect, relative relief, distance to river, geological units, soil type, land use and distance to road. The obtained susceptibility map was validated using cross-time technique, and was collaborated with the frequency-area statistics to respond to ‘when landslide will occur’ and ‘how large it will be’. As for the judgment of the consequences of future landslides, expert opinion was used considering available literature and characteristic of the study area. We have only considered economic loss in terms of physical damage of buildings, roads and agricultural lands for the landslide risk analysis. From this study, we understand the following: (1) the hazard map obtained from conversion of the susceptibility map gives spatial probability and the area of an expected landslide will be greater than 500m² in the next 2 years, (2) the landslide risk map shows that 24% of the total area is in high risk; 30% in moderate risk; 45% in low risk and no risk covers only 1% of the total area, and (3) the loss will be high in agricultural lands, while it will be low in the road structures and buildings.     

Tjörnes fracture zone. New and old seismic evidences for the link between the North Iceland rift zone and the Mid-Atlantic ridge

The Tjörnes facture zone (TFZ) connects the EW extension of the Mid-Atlantic ridge north of Iceland to the extension of the North volcanic zone (NVZ) of Iceland. Earthquakes up to magnitude 7 (Ms) can occur in TFZ, volcanic eruptions have been observed and large crustal deformations are expected in similar way as have been observed in the NVZ. Most of the zone is below ocean, which limits the historical information and geological observations. For studying the dynamics of the zone we must rely on interpretation and modelling based on seismic observations, especially on microearthquake observations for the last 10 years. In this paper we demonstrate how microearthquakes can be applied to map the details of the plate boundary, and how this information can be applied to find epicenters and fault planes of large historical earthquakes, also how seismic information can be applied in dynamic modelling and to infer spatial and temporal interplay in activity, and to enhance hazard assessment.     

地圈动力学--地质环境、灾害与工程研究基础

从可持续发展理念出发 ,探讨工程地质学的学科使命和发展问题。作者指出 ,地圈系统的相互作用和动力过程直接决定着人类生存和活动所依赖的环境、所承受的灾害及工程建设的问题和条件 ,地圈动力学研究应是工程地质作用评价、过程预测的基础。作者建议对工程地圈系统的相互作用和动力过程进行深入系统的研究。这将有利于工程地质学科的整体发展和提高。     

Monitoring the temporal development of natural hazard risks as a basis indicator for climate change adaptation

The potential effects of climatic changes on natural risks are widely discussed. But the formulation of strategies for adapting risk management practice to climate changes requires knowledge of the related risks for people and economic values. The main goals of this work were (1) the development of a method for analysing and comparing risks induced by different natural hazard types, (2) highlighting the most relevant natural hazard processes and related damages, (3) the development of an information system for the monitoring of the temporal development of natural hazard risk and (4) the visualisation of the resulting information for the wider public. A comparative exposure analysis provides the basis for pointing out the hot spots of natural hazard risks in the province of Carinthia, Austria. An analysis of flood risks in all municipalities provides the basis for setting the priorities in the planning of flood protection measures. The methods form the basis for a monitoring system that periodically observes the temporal development of natural hazard risks. This makes it possible firstly to identify situations in which natural hazard risks are rising and secondly to differentiate between the most relevant factors responsible for the increasing risks. The factors that most influence the natural risks could be made evident and eventual climate signals could be pointed out. Only with this information can the discussion about potential increases in natural risks due to climate change be separated from other influencing factors and be made at an objective level.     

Permafrost and climate in Europe: Monitoring and modelling thermal,geomorphological and geotechnical responses

We present a review of the changing state of European permafrost within a spatial zone that includes the continuous high latitude arctic permafrost of Svalbard and the discontinuous high altitude mountain permafrost of Iceland, Fennoscandia and the Alps. The paper focuses on methodological developments and data collection over the last decade or so, including research associated with the continent-scale network of instrumented permafrost boreholes established between 1998 and 2001 under the European Union PACE project. Data indicate recent warming trends, with greatest warming at higher latitudes. Equally important are the impacts of shorter-term extreme climatic events, most immediately reflected in changes in active layer thickness. A large number of complex variables, including altitude, topography, insolation and snow distribution, determine permafrost temperatures. The development of regionally calibrated empirical-statistical models, and physically based process-oriented models, is described, and it is shown that, though more complex and data dependent, process-oriented approaches are better suited to estimating transient effects of climate change in complex mountain topography. Mapping and characterisation of permafrost depth and distribution requires integrated multiple geophysical approaches and recent advances are discussed. We report on recent research into ground ice formation, including ice segregation within bedrock and vein ice formation within ice wedge systems. The potential impacts of climate change on rock weathering, permafrost creep, landslides, rock falls, debris flows and slow mass movements are also discussed. Recent engineering responses to the potentially damaging effects of climate warming are outlined, and risk assessment strategies to minimise geological hazards are described. We conclude that forecasting changes in hazard occurrence, magnitude and frequency is likely to depend on process-based modelling, demanding improved understanding of geomorphological process-response systems and their impacts on human activity.     

中国大陆密度和地震波速扰动异常的年龄属性研究

大陆动力学研究需要物质随空间和时间的变化的信息.三维密度和地震波速度扰动图像反映岩石圈物质的空间分布,要和大地构造学中的时间尺度信息综合起来,才能恢复动力学作用的过程.本文通过对比不同构造期的构造图和地壳不同深度的地球物理性质图像,研究中国大陆密度以及地震波速度扰动和构造事件的相关度.研究表明,岩石圈地幔的密度和波速扰...     

The significance of quality of life and sustainability at the urban–rural fringe in the making of place-based community

Understandings of community in urban–rural fringe locations in Ireland are explored in this paper. As a specific space at the interface between the urban and the rural the fringe incorporates processes of rapid physical, social, and demographic change. These give rise to a range of complex and often competing dynamics, that impact on people and place in a variety of ways. Among the main preoccupations and concerns in these rapidly evolving fringe locations are those relating to what can broadly be described as ‘quality of life’. How this concept is understood across different groups situated within the spatial setting of the fringe, and how it influences the development of a sustainable community there, are central to this discussion. Drawing on household interviews from four case-study locations surrounding Galway City, Ireland, this paper examines how quality of life is experienced across a range of social and spatial dimensions that relate to these locations, and the extent to which they provide a common set of interests around which community may be built. From a wider knowledge perspective, it contributes to debates about how the concept of community provides explanatory power regarding the way in which individuals are associated with one another on the basis of a set of shared interests or concerns within a particular spatial setting.     

Use of quantitative landslide hazard and risk information for local disaster risk reduction along a transportation corridor: a case study from Nilgiri district, India

The objective of analyzing hazard and risk in an area is to utilize the result in selecting appropriate landslide risk reduction strategies. However, this does not happen always, and most often results of the hazard and risk analysis remain at an academic level. The under or non-utilization of results in pre-disaster planning could be due to several reasons, including difficulties in understanding the scientific content/meaning of the models, and lack of information on the practical significance and utility of the models. In this study, an attempt is made to highlight the uses of hazard and risk information in different landslide risk reduction strategies along a transportation corridor in Nilgiri, India. At first, a quantitative analysis of landslide hazard and risk was made. The obtained information was then incorporated in risk reduction options such as land use zoning, engineering solutions, and emergency preparedness. For emergency preparedness, the perception of the local Nilgiri communities toward landslide risk was evaluated and simplified maps were generated for the benefit and understanding of end users. A rainfall threshold-based early warning system was presented, which could be used in risk awareness programs involving public participation. The use of quantitative risk information in the cost-benefit analysis for the planning of structural measures to protect the road and railway alignments was also highlighted, and examples were shown how the transport organizations could implement these measures. Finally, the study provided examples of the utility of hazard and risk information for spatial planning and zoning, indicating areas where the landslide hazard is too high for planning future developments.     

四川罗家青杠岭崩塌风险的定量评价研究

我国多山,崩塌灾害频繁发生,相应的风险评价也得到了越来越多的关注。由于崩塌发生和运移过程的高度不确定性以及历史数据的不完备,往往很难进行相应的定量风险评价。四川罗家青杠岭的崩塌现场非常典型,而且现场资料较全、历史数据较多并且明确,是开展崩塌风险定量研究的很好实例。通过现场工程地质调查、测绘和统计分析,确定了历史崩塌的物源区、堆积区、最大运移距离、年发生概率以及坡体上的4块典型危岩体A-D。基于历史崩塌堆积区的块石统计特征以及物源区危岩体失稳启动位置的不确定性,利用二维Rockfall模拟软件对所在坡面的恢复系数及摩擦系数进行了反演。在此基础上,对危岩体A-D失稳后的运动特征进行了随机性数值模拟和统计分析,从而确定了崩塌的到达概率。基于崩塌发生概率、到达概率、承灾体时空分布概率和易损性的乘积,作者对罗家青杠岭崩塌进行了定量风险评价。评价结果表明,危岩体A和D的风险值处于不可接受的风险区间,块石B和C的风险值处于警告的风险区间,严重威胁着坡脚附近居民的生命财产安全,有必要采取相应的防灾减灾措施。     

Estimation of volcanic hazards based on Cox stochastic processes

Assessments of the probability and the consequences of future volcanic activity can be critical aspects when evaluating the safety of the population and of industrial plants. A new methodology has been developed for the probabilistic modelling of volcanic hazards based on regional volcanic data that facilitates the production of probabilistic hazard maps for various volcanic scenarios (lava flows, tephra). The stochastic model is based on Cox processes and allows account to be taken of the observed temporal and spatial correlation inherent in volcanic eruptions. The model is applied to the Quaternary field of the Osteifel region where the forecast number of future eruptions and the probabilities related to the different scenarios are estimated using a Monte Carlo approach. The obtained hazard maps of future volcanic events are part of a comprehensive hazard analysis and serve as a major input for the risk analysis that will determine the consequences of forecast volcanic activity at the site.     

The role of coupling and embeddedness in risk evolution: rethinking the snow event in early 2008, China

New forms of hazards generated by extreme weather pose new challenges to emergency management. The purpose of this paper is to identify a typical evolution dynamics by analyzing coupling and embeddedness in risk evolution via critical infrastructure system under extreme weather. Evidence from the snow event in early 2008, China, is used to draw the viewpoint and support the argument. The paper identifies the dynamics that how a natural hazard of extreme weather evolves into a social crisis and how coupling and embeddedness contribute to the evolution. This paper makes it evident that the impact of natural hazard to a society can obtain amplification through coupling and embeddedness. Therefore, new challenges in risk evolution should become a highlighted direction for further research. This paper sheds light on a new profile for social impact research of natural hazard and provides new insights into systems thinking on emergency management.