Landslide hazard and risk assessment mapping of mountainous terrains - a case study from Kumaun Himalaya, India

Landslides are studied systematically in order to evaluate the nature of hazard and the damages to the human life, land, roads, buildings and other properties. This can be expressed in terms of risk, which is a function of hazard probability and damage potential. A risk map will indicate the priorities for landslide hazard management. A new approach to risk assessment mapping using a risk assessment matrix (RAM) is presented.     

Landslide risk assessment and management: an overview

Landslides can result in enormous casualties and huge economic losses in mountainous regions. In order to mitigate landslide hazard effectively, new methodologies are required to develop a better understanding of landslide hazard and to make rational decisions on the allocation of funds for management of landslide risk. Recent advances in risk analysis and risk assessment are beginning to provide systematic and rigorous processes to enhance slope management. In recent years, risk analysis and assessment has become an important tool in addressing uncertainty inherent in landslide hazards.This article reviews recent advances in landslide risk assessment and management, and discusses the applicability of a variety of approaches to assessing landslide risk. Firstly, a framework for landslide risk assessment and management by which landslide risk can be reduced is proposed. This is followed by a critical review of the current state of research on assessing the probability of landsliding, runout behavior, and vulnerability. Effective management strategies for reducing economic and social losses due to landslides are described. Problems in landslide risk assessment and management are also examined.     

The effects of decentralization on the production and use of risk assessment: insights from landslide management in India and Italy

Landslides represent a major threat to human life, property and the environment. Landslide hazard and risk assessments seek to inform the policy and practice of landslide hazard risk management, for example, by identifying high-risk areas so that appropriate policy and private actions could be taken in terms of preventive and mitigative measures. We examine whether a decentralized risk assessment system leads to better assessment outcomes compared to a centralized risk assessment system. The paper is based on a comparative study of two countries??India and Italy??and their responses to landslide risk. Our results indicate a causal relationship between decentralization and three outcomes. First, decentralization appears to be conducive to the more rapid and more complete assessment of risks in local places, through mapping at an appropriate scale. Second, decentralization appears to foster greater and more transparent communication of risk assessment products, such as maps. Third, decentralization appears to lead to a more open, and at times contentious, public discourse over how to interpret and respond to the information contained in the risk assessments and maps. However, in practice, decentralization faces serious institutional resistance. Our analysis does not preclude other risk assessment outcomes or competing explanations for differences in risk assessment and management outcomes. Rather, it provides an understanding of the direction in which the institutional change may be driven for bringing about more effective risk assessments and their use.     

物元模型在滑坡灾害风险预测中的应用

应用物元理论，提出了滑坡灾害风险预测物元综合评判的基本流程，并以危险性预测为例讨论了物元集合的建立、等级关联度的确定等关键技术问题，建立了滑坡灾害风险综合评判的物元模型；运用物元模型与GIS技术相结合，对三峡水库蓄水条件下巴东新县城的滑坡灾害进行了危险性、易损性、风险性综合预测研究，证明了物元模型在区域滑坡灾害风险预测中的应用可行性；同时指出了所存在的问题及可能解决的途径。     

区域滑坡灾害预测预警与风险评价

区域滑坡灾害预测预警是滑坡灾害研究领域的难点和热点。过去10多年来在这方面的研究主要集中在区域降雨与地质环境的结合方面。文章总结了目前国内外滑坡灾害预测预报、预警和风险管理研究现状,认为把滑坡灾害预警预报与风险管理相结合是减灾防灾的需要,也是今后该领域研究的发展趋势。文章从区域滑坡灾害空间预测、时间预警预报的角度提出了滑坡灾害预测预报的分类和理论基础,并在此基础上,利用MapGIS软件平台进行二次开发,建立了基于WebGIS的滑坡灾害信息管理系统和实时预警发布系统。以2004年"云娜"台风期间浙江省永嘉县滑坡灾害预警预报为例,进行了滑坡危险性预测、人口易损性预测、经济易损性预测到风险预测的实例研究。     

滑坡风险评价的理论与方法研究

作为防灾减灾的重要措施之一,滑坡风险评价已经成为近年来国际上滑坡研究的热点,并形成了较为完备的滑坡风险管理体系。国内的滑坡风险研究则起步较晚,滑坡风险评价的关键支撑技术体系尚未建立。本文对滑坡风险评价中的关键理论和方法进行梳理,阐述了国际滑坡风险评价的理论框架和技术流程,介绍了国内外滑坡易发性、危险性和风险评价的最新进展,评述了滑坡易发性评价、扩展范围预测、频率分析以及承灾体易损性评价的主要方法,阐明了现阶段滑坡风险评价的重点领域和前沿科学问题,并对滑坡灾害的风险评价提出了三点展望。     

基于GIS的巴东新县城滑坡灾害风险系统

本文提出了基于GIS的滑坡灾害风险预测系统流程。并将滑坡灾害风险评价模型与GIS技术先进的图形处理和空间分析功能相结合,建立了巴东县新县城区滑坡灾害风险预测系统。系统由信息管理子系统、危险性预测子系统、易损性预测子系统、风险预测子系统四大子系统构成。系统在对相关信息进行采集、存贮、检索和管理的基础上,结合物元模型、BP模型等专业预测模型,实现了滑坡灾害危险性、易损性评价,最终取得了滑坡灾害风险分布图,为三峡库区内各县的滑坡灾害信息管理和风险预测提供了新途径。预测成果可为研究区的国土规划和移民工程的顺利实施提供依据和保障。     

国际滑坡风险评估与管理指南研究综述

总结了国际主流滑坡风险评估与管理技术指南的进展和现状,综述了滑坡风险管理范畴中包含的理论和技术框架,研究精度和层次,滑坡编录、易发性、危险性和风险分区研究的技术方法;指出了滑坡风险分区成果的误差来源和可靠性验证方法;基于滑坡风险分区的研究成果,提出了土地利用规划中风险控制措施的建议。总结了主流国家和地区滑坡风险管理的发展历程和经验,结合中国地质灾害防灾减灾的现状,强调了出版滑坡风险评估与管理指南的紧迫性,并展望了滑坡等突发地质灾害风险评估与管理的发展前景。     

Landslide vulnerability and risk assessment for multi-hazard scenarios using airborne laser scanning data (LiDAR)

Landslide hazard, vulnerability, and risk-zoning maps are considered in the decision-making process that involves land use/land cover (LULC) planning in disaster-prone areas. The accuracy of these analyses is directly related to the quality of spatial data needed and methods employed to obtain such data. In this study, we produced a landslide inventory map that depicts 164 landslide locations using high-resolution airborne laser scanning data. The landslide inventory data were randomly divided into a training dataset: 70 % for training the models and 30 % for validation. In the initial step, a susceptibility map was developed using logistic regression approach in which weights were assigned to every conditioning factor. A high-resolution airborne laser scanning data (LiDAR) was used to derive the landslide conditioning factors for the spatial prediction of landslide hazard areas. The resultant susceptibility was validated using the area under the curve method. The validation result showed 86.22 and 84.87 % success and prediction rates, respectively. In the second stage, a landslide hazard map was produced using precipitation data for 15 years. The precipitation maps were subsequently prepared and show two main categories (two temporal probabilities) for the study area (the average for any day in a year and abnormal intensity recorded in any day for 15 years) and three return periods (15-, 10-, and 5-year periods). Hazard assessment was performed for the entire study area. In the third step, an element at risk map was prepared using LULC, which was considered in the vulnerability assessment. A vulnerability map was derived according to the following criteria: cost, time required for reconstruction, relative risk of landslide, risk to population, and general effect to certain damage. These criteria were applied only on the LULC of the study area because of lack of data on the population and building footprint and types. Finally, risk maps were produced using the derived vulnerability and hazard information. Thereafter, a risk analysis was conducted. The LULC map was cross-matched with the results of the hazard maps for the return period, and the losses were aggregated for the LULC. Then, the losses were calculated for the three return periods. The map of the risk areas may assist planners in overall landslide hazard management.     

基于多期DEM和滑坡强度的滑坡风险评估

滑坡危险性定量评估是滑坡风险评估中的关键和难点,也是当前国际风险管理研究中的热点问题.以滑坡密集分布的黑方台南塬为研究区,以32处典型滑坡为研究对象,依据多期三维数字高程模型(DEM),提出了一种基于强度的滑坡危险性定量评估技术方法.根据多期三维地形信息的解译及野外调查,编制多期滑坡分布图,计算滑坡活动的频率.利用GIS技术,利用滑坡体积与速度的乘积计算滑坡强度.将滑坡危险性定义为滑坡频率和滑坡强度的乘积,同时调查和分析了黑方台地区各类承灾体的类型、价值及其在相应滑坡强度下的易损性,在此基础上开展了单体滑坡风险评估和黑方台南塬滑坡风险区划.     

崩塌滑坡地质灾害风险排序方法研究

我国地质灾害具有点多面广的分布特点,而地质灾害风险管控人力和能力有限,因此需要开展地质灾害风险排序工作,筛选出优先管控的地质灾害隐患点,确保地质灾害风险管控对策实施的针对性和高效性。地质灾害风险排序的实质是运用定量化风险评价计算出每处隐患点的风险值,然后根据风险值开展排序工作。目前定量化风险评价模型多用于单个地质灾害点风险评价,并未应用于大范围地质灾害风险排序工作,且模型较为复杂,推广应用较难。在分析崩塌、滑坡地质灾害与其环境因素间的响应关系及规律的基础上,提取崩塌、滑坡地质灾害的主控环境因子与诱发因子,联合人口、物质、资源等易损性因子建立地质灾害风险评价指标体系;基于岩石工程系统相互作用矩阵与专家打分法确定各级地质灾害风险评价指标因子权重,构建地质灾害风险评分体系;并根据风险评价定义,提出了能够快速定量化的简易地质灾害风险计算模型。以贵州省98处地质灾害隐患点为例,开展模型应用验证,风险排序结果与灾害管理机构主观认识的实际风险一致,验证了本模型的合理性与有效性,提高了地质灾害风险管控能力与效率。     

Landslide hazard and risk assessment: a?case study from the Hlohovec–Sered’ landslide area in south-west Slovakia

Landslide hazard or susceptibility assessment is based on the selection of relevant factors which play a role on the slope instability, and it is assumed that landslides will occur at similar conditions to those in the past. The selected statistical method compares parametric maps with the landslide inventory map, and results are then extrapolated to the entire evaluated territory with a final product of landslide hazard or susceptibility map. Elements at risk are defined and analyzed in relation with landslide hazard, and their vulnerability is thus established. The landslide risk map presents risk scenarios and expected financial losses caused by landslides, and it utilizes prognoses and analyses arising from the landslide hazard map. However, especially the risk scenarios for future in a selected area have a significant importance, the literature generally consists of the landslide susceptibility assessment and papers which attempt to assess and construct the map of the landslide risk are not prevail. In the paper presented herein, landslide hazard and risk assessment using bivariate statistical analysis was applied in the landslide area between Hlohovec and Sered?? cities in the south-western Slovakia, and methodology for the risk assessment was explained in detail.     

论变化环境下流域管理的知识创新

提出全球气候变化与世界社会经济动荡等变化环境下流域可持续发展的科学内涵、制约因素以及解决途径。以自然与社会协同进化的复杂系统作为变化环境下流域概念的抽象表征,以科研能力与管理能力作为流域可持续发展的重要影响因素,以流域管理中科学研究与管理实践的相互作用机理为出发点,分析当前流域管理中科学研究与管理实践的种种错位,提出适应变化环境的流域管理知识创新机制,为提高流域科研水平、充分发挥科学在流域可持续发展中的作用提供理论支撑。     

Application of a RS- and GIS-based semi-quantitative approach (analytical hierarchy process – AHP) in landslide hazard risk assessment of the Shivkhola Watershed,Darjiling Himalaya

The present study deals with the application of analytical hierarchy process to prepare landslide hazard risk map of the Shivkhola Watershed applying remote sensing and geographic information system (GIS). Firstly, to integrate all the required thematic data layers and to prepare landslide susceptibility map, prioritised class rating value and prioritised factor rating value were obtained by developing couple-comparing matrix with a reasonable consistency and with the help of MATLAB software after Saaty. Three important risk factor/element maps, that is, weighted land use/land cover map, road contributing area map and settlement density map, were developed and their weighted linear combination was performed to prepare landslide risk exposure map. Then by integrating landslide susceptibility map and landslide risk exposure map, a classification was incorporated on ARC GIS Platform to prepare landslide hazard risk map. To evaluate the validity of the landslide hazard risk map, probability/chance of landslide hazard risk event has been estimated by means of frequency ratio between landslide hazard risk area (%) and number of risk events (%) for each landslide hazard risk class. Finally, an accuracy assessment was also made on ERDAS Imagine (8.5) which depicts that the classification accuracy of the landslide hazard risk map was 92.89 with overall Kappa statistics of 0.8929.     

Global landslide and avalanche hotspots

Allocating resources for natural hazard risk management has high priority in development banks and international agencies working in developing countries. Global hazard and risk maps for landslides and avalanches were developed to identify the most exposed countries. Based on the global datasets of climate, lithology, earthquake activity, and topography, areas with the highest hazard, or “hotspots”, were identified. The applied model was based on classed values of all input data. The model output is a landslide and avalanche hazard index, which is globally scaled into nine levels. The model results were calibrated and validated in selected areas where good data on slide events exist. The results from the landslide and avalanche hazard model together with global population data were then used as input for the risk assessment. Regions with the highest risk can be found in Colombia, Tajikistan, India, and Nepal where the estimated number of people killed per year per 100 km² was found to be greater than one. The model made a reasonable prediction of the landslide hazard in 240 of 249 countries. More and better input data could improve the model further. Future work will focus on selected areas to study the applicability of the model on national and regional scales.     

Knowing wildfire risk: Scientific interactions with risk mitigation policy and practice in Victoria,Australia

Over the past decade, major landscape wildfires (or ‘bushfires’ in Australia) in fire-prone countries have illustrated the seriousness of this global environmental problem. This natural hazard presents a complex mesh of dynamic factors for those seeking to reduce or manage its costs, as ignitions, hazard behaviour, and the reactions of different human and ecological communities during and after hazard events are all extremely uncertain. But while those at risk of wildfire have been subject to significant research, the social dimensions of its management, including the role of science, have received little attention. This paper reports on a case study of the Barwon-Otway area of Victoria in Australia, a high wildfire risk area that has recently been a pilot site for a new risk mitigation strategy utilising the wildfire simulation model PHOENIX RapidFire. Against simple equations between ‘more science’ and ‘less uncertainty,’ this paper presents results from interviews and a workshop with practitioners to investigate how scientific research interacts with and informs both wildfire policy and practice. We suggest that attending to cultural and social specificities of the application of any technical innovation—such as next generation modelling—raises questions for future research about the roles of narrative, performance, and other knowledges in the sedimentation of science.     

Quantitative hazard and risk assessment for slow-moving landslides from Persistent Scatterer Interferometry

Preparation of reliable landslide hazard and risk maps is crucial for hazard mitigation and risk management. In recent years, various approaches have been developed for quantitative assessment of landslide hazard and risk. However, possibly due to the lack of new data, very few of these hazard and risk maps were updated after their first generation. In this study, aiming at an ongoing assessment, a novel approach for updating landslide hazard and risk maps based on Persistent Scatterer Interferometry (PSI) is introduced. The study was performed in the Arno River basin (central Italy) where most mass movements are slow-moving landslides which are properly within the detection precision of PSI point targets. In the Arno River basin, the preliminary hazard and risk assessment was performed by Catani et al. (Landslides 2:329–342, 2005) using datasets prior to 2002. In this study, the previous hazard and risk maps were updated using PSI point targets processed from 4 years (2003–2006) of RADARSAT images. Landslide hazard and risk maps for five temporal predictions of 2, 5, 10, 20 and 30 years were updated with the exposure of losses estimated in Euro (€). In particular, the result shows that in 30 years a potential loss of approximate €3.22 billion is expected due to these slow-moving landslides detected by PSI point targets.     

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。     

An InSAR and depth-integrated coupled model for potential landslide hazard assessment

Assessing the hazard of potential landslides is crucial for developing mitigation strategies for landslide disasters. However, accurate assessment of landslide hazard is limited by the lack of landslide inventory maps and difficulty in determining landslide run-out distance. To address these issues, this study developed a novel method combining the InSAR technique with a depth-integrated model. Within this new framework, potential landslides are identified through InSAR and their potential impact areas are subsequently estimated using the depth-integrated model. To evaluate its capability, the proposed method was applied to a landslide event that occurred on November 3, 2018 in Baige village, Tibet, China. The simulated results show that the area with a probability of more than 50% to be affected by landslides matched the real trimlines of the landslide and that the accuracy of the proposed method reached 85.65%. Furthermore, the main deposit characteristics, such as the location of maximum deposit thickness and the main deposit area, could be captured by the proposed method. Potential landslides in the Baige region were also identified and evaluated. The results indicate that in the event of landslides, the collapsed mass has a high probability to block the Jinsha River. It is therefore necessary to implement field monitoring and prepare hazard mitigation strategies in advance. This study provides new insights for regional-scale landslide hazard management and further contributes to the implementation of landslide risk assessment and reduction activities.

     

The risk assessment of landslide hazards in Shiwangmiao based on intuitionistic fuzzy sets-Topsis model

The landslide hazard is one of the geological hazards in mountainous zone. Its occurrence is controlled by many factors. To assess the risk level of landslide in Shiwangmiao accurately, intuitionistic fuzzy sets-Topsis model is introduced at first; secondly, the decisive matrix about the intuitionistic fuzzy sets is established, and the index weight coefficients considering the uncertainty of assessment indices are determined by using the Entropy weight method, then the weighed decisive matrix is obtained. Finally, degree of membership at different levels about the landslide is determined based on the ranking sequence of degree of membership, the risk level corresponding to the maximum degree of membership is final assessment level. The conclusions are drawn that accurate rate of risk estimation about landslide hazards is very high based on the intuitionistic fuzzy sets model in comparison with the current specifications, and the method is feasible for the risk assessment of landslide hazards, so it provides a new method and thoughts to assess the risk level of landslide in future.