Assessment of provincial social vulnerability to natural disasters in China

Assessment of social vulnerability has been recognized as a critical step to understand natural hazard risks and to enhance effective response capabilities. Although significant achievements have been made in social vulnerability researches, little is know about the comprehensive profile of regional social vulnerability in China. In this study, the social vulnerability to natural hazards was firstly divided into socioeconomic and built environmental vulnerability. Then, using factor analysis, we identified the dominant factors that influence the provincial social vulnerability in China to natural hazards based on the socioeconomic and built environmental variables in 2000 and 2010 and explored the spatial patterns of social vulnerability. The results indicated that the provincial social vulnerability in China showed significant regional differences. The social vulnerability in the southeastern and eastern regions of China was greater than its northern and central parts over the past decade. Economic status, rural (proportion of agricultural population and percentage of workers employed in primary industries), urbanization, and age structure (children) were the dominant driving forces of variations in provincial socioeconomic vulnerability in two studied years, while lifelines and housing age could explain most of changes in built environmental vulnerability in 2000 and 2010. There were no statistically significant correlations between social vulnerability and disaster losses (p > 0.05), indicating the impact of disasters was also related to the intensity of hazards and exposure. Disaster relief funds allocated to each province of China depended more on its disaster severity than the regional integrated social vulnerability over the past decade. These findings would provide a scientific base for the policy making and implementation of disaster prevention and mitigation in China.     

基于风险度的青海省暴雨洪涝灾害风险评估

基于自然灾害风险原理,结合青海省气象数据、地理信息数据、社会经济数据,并利用主成分分析法、GIS自然断点法对青海省暴雨洪涝灾害致灾因子危险度、承载体易损度评估模型以及暴雨洪涝灾害风险度进行评估,结果表明：青海省不同强度降水日数均呈增多趋势,新世纪以来中雨日数及强降水日数增加趋势尤为明显;暴雨洪涝灾害致灾因子危险度呈由东南向西北降低的趋势,承载体易损度为东北部地区最高,南部以及西部地区最低;暴雨洪涝风险较高的地区主要集中在东部地区,互助、湟中、大通、西宁为高风险区,东部大部地区、环青海湖地区为较高风险区,西部地区为低风险区。该评估结果可以在气象灾害风险管理业务中进行应用,可以加强对暴雨洪涝灾害风险的影响程度及影响区域的判定,为地方防灾减灾救灾工作提供科学依据。     

Characterizing the spatial distribution of typical natural disaster vulnerability in China from 2010 to 2017

Natural disaster vulnerability can intuitively reflect the susceptibility of an area to environmental changes. Better understanding the spatial distribution of natural disaster vulnerability is a critical process for taking effective adaptation and management. Although significant achievements have been made in disaster vulnerability, few studies are known about natural disaster vulnerability at the national scale, especially from the typical natural disaster events in China. In this study, with normalizing selected indicators and calculating vulnerability index, we analyzed the spatial distribution of natural disasters vulnerability during 2010–2017 using the geospatial techniques. The results showed that natural disaster vulnerability has certain spatial differences, but different natural disaster can occur in the same area during the study period. Drought disaster can occur in all regions of China, especially in Inner Mongolia. Flood disaster is mainly concentrated in the middle and lower reaches of the Yangtze River and the Yellow River Basin. The wind and storm disaster is chiefly in the northern regions in China. The freezing disaster is widely distributed in China. Furthermore, the regions with low vulnerability were primarily distributed in the eastern coastal region, indicating that the rapid development of economy and technology can resist or mitigate natural disaster to a certain extent. This study offers a solution to study natural disasters and provides scientific basis for disaster prevention and mitigation actions.

     

Economic risk maps of floods and earthquakes for European regions

Europe experiences different natural hazards and subsequent risks that have various effects on the development of its regions. The spatial significance of hazards can be expressed as an economic risk when combining hazard potential with vulnerability data. Two examples of European natural hazard maps on floods and earthquakes, as well as the resulting risk profiles of regions (combination of hazard potential and vulnerability) give a first impression on the spatial characters of hazards in Europe and their potential impact on further spatial development. The economic risk maps enable a view on the spatial dimension of the economic damage potential of flood and earthquakes, pointing out comparable situations across Europe with the aim to facilitate targeted responses and policies. The spatial character of a hazard is either defined by spatial effects that might occur in case of a disaster or by the possibility of spatial planning responses. The integration of the economic vulnerability of a region (regional GDP per capita, population density) leads to a classification of areas according to their economic risk or damage potential towards hazards. These synthetic risk profiles are presented as risk maps of European regions in administrative boundaries. Obtained information can be of interest for spatial planning and development strategies, e.g. economic risk profile of regions can influence the targets of investments and could thus be an important background for structural funding.     

Analysis of social vulnerability to hazards in China

To improve natural disaster management, it is important to recognize the variability of the vulnerable populations exposed to hazards and to develop location-based emergency plans accordingly. This paper presents a mathematical model to establish a model of social vulnerability index (SoVI), which includes 12 social variables, and the regional social vulnerability to natural hazards was formulated by them. Taking a city as statistical unit, the variability of vulnerability to natural hazards was explored among the 323 cities based on the SoVI. The results indicate that vulnerability is a location-based regional phenomenon, with the most vulnerable cities being located in the southwest of China and the eastern areas being generally less vulnerable. The results will be helpful for policy makers to formulate disaster management plans, which can be beneficial for people in more vulnerable areas who are responding to, coping with, and recovering from natural disasters.     

Exploring the characteristics of major natural disasters in China and their impacts during the past decades

The exploration of the characteristics of natural disasters (NDs) and their impacts have important implications for guiding disaster prevention and mitigation. This paper discussed the characteristics of the major NDs that occurred in mainland China between 1980 and 2011 based on the number of disasters and fatalities, the affected population, and the resulting economic damages. We further examined the relationships between the level of social/economic development and the disaster losses. At last, we also explored the trend variations in disaster losses and losses expressed as a percentage of gross domestic product (losses/GDP) for 31 provinces in China over the period from 1990 to 2011. The results show that over the past three decades, the number of major NDs and the number of affected population appear to exhibit a detectable increasing trend, while the direct economic losses and the deaths show a slight increase trend. The correlations between the number of disasters and the economic losses as well as deaths and between the economic losses and socioeconomic status were not significant (p > 0.05), which indicates that the growth in the number of disasters do not result in a significant increase in the disaster losses. Further investigations demonstrate that as economies develop, there are fewer losses/GDP in China over the past two decades. The per capita accumulative losses and losses/GDP in the western and central regions were higher than that in the eastern parts of China. There are significant regional differences in the trends in disaster losses and losses/GDP in China. Statistics also indicate that more than 70 % provinces in underdeveloped regions show an increasing trend in disaster losses, whereas exceeding 90 % provinces exhibit a decreasing trend in their losses/GDP. These results suggest that the economic development may have played an important role in improving the capacity of disaster prevention and reduction.     

On the driving forces of historical changes in the fatalities of tropical cyclone disasters in China from 1951 to 2014

Tropical cyclone (TC) disasters have frequently caused casualties in the coastal areas of China. According to the statistics of dead and missing people due to TCs from 1951 to 2014, the number of fatalities has been significantly decreasing over time. However, deadly TC events have still caused great losses of life in recent years, which are characterized as significant abrupt fluctuations superimposed along the downward trend of the long-term fatality time series. The numbers of fatalities caused by TC disasters are influenced by variables such as the intensity of TC hazards, the population exposed to TCs and the vulnerability of people to TC hazards. It is thus of great significance to analyze their temporal characteristics and understand the forces driving these changes. First, the time series of the TC wind, precipitation, spatial distribution of population, fatality and disaster risk reduction (DRR) measures of China from 1951 to 2014 are reconstructed. Second, the improved power dissipation index, total precipitation, integrated intensity and index of exposed population are calculated, and the population vulnerability indices, including mean and relative fatality rates, are derived. Third, the change trend of each index is detected using the Mann–Kendall test. Finally, the main driving factors of the long-term change trend and fluctuations of the TC fatalities are analyzed by a negative binomial regression model and standard deviation statistics. It is found that the decrease in vulnerability based on the improvement in structural and non-structural measures is the main driving force of the decreases in fatalities over the past six decades. Although the total population and exposure have increased dramatically in the coastal areas of China, their contributions to the increase in the fatality risk were counteracted by the decrease in vulnerability. Abrupt and catastrophic disasters were mostly caused by TCs with hazards of high intensity that surpassed the capacity of structural measures; the lack of forecasting or early warning, as well as improper emergency response actions, may also have triggered the great loss of lives. To reduce the fatalities of future TCs, especially those that may exceed the capacity of structural measures, the enhancement of non-structural measures and the adaptation of resilience strategies should be priorities for future people-centered disaster management.

     

Multilayer-exposure maps as a basis for a regional vulnerability assessment for landslides: applied in Waidhofen/Ybbs,Austria

Assessments of natural hazards and risks are beneficial for sustainable planning and natural hazard risk management. On a regional scale, quantitative hazard and risk assessments are data intensive and methods developed are difficult to transfer to other regions and to analyse different periods in a given region. Such transfers could be beneficial regarding factors of global change influencing the patterns of natural hazard and risk. The aim of this study was to show the landslide exposure of different elements at risk in one map, e.g. residential buildings and critical infrastructure, as a solid basis for an in-depth analysis of vulnerability and consequent risk. This enables to overcome the data intensive assessments on a regional scale and highlights the potential hotspots for risk analysis. The study area is located in the alpine foreland in Lower Austria and comprises around 112 km². The results show the different levels of exposure, as well as how many layers of elements at risk are affected. Several exposure hotspots can be delineated throughout the study area. This allows a decision on in-depth analysis of hotspots not only by indicated locations but also by a rank resulting from the different layers of incorporated elements at risk.     

基于自然灾害风险评价框架的省级地质灾害风险区划方法探讨——以吉林省为例

地质灾害风险区划是地质灾害风险管理与防治的有效手段之一,对于科学防治地质灾害具有重要意义。基于自然灾害风险理论,从致灾因子危险性,承灾体暴露性和脆弱性以及防灾减灾能力（恢复力）等入手,选取评价指标,构建省级地质灾害风险评价模型,对全省地质灾害进行风险区划。该模型在吉林省地质灾害风险区划中应用表明,评价结果合理,与野外调查情况吻合,可以为规划和地质灾害防治等工作提供依据。     

Re-specifying disaster risk: concepts,methods, and models

The discussion on the social-ecological dimensions of hazards is constantly evolving. This paper explores the trajectory of research relating to hazards and their impact on vulnerable human populations. Interpretations of disaster risk have included estimating losses in terms of human life and property, and analyzing the social mechanisms in place that exacerbate or mitigate a population’s sensitivity to hazard events. In keeping with recent trends in research relating to disaster risk, the paper focuses on the social dimension of vulnerability and the contribution of social structures and relationships in building community resilience. Institutional frameworks and policies in particular determine the quantity and quality of resources and services available to people that contribute to resilience over time. The hazard-risk-location-model (HRLM) is proposed that is based on re-specifying disaster risk in terms of exposure and coping ability to capture the focus on social vulnerability and resilience. The framework of the HRLM incorporates the following components: (1) linkages within existing social capital; (2) spatial variation in social and institutional frameworks; (3) positive and negative feedbacks; and (4) characteristics of the hazard event. The model contributes to the range of place-based assessments designed to address the human-environmental impacts of hazards and disasters.     

Socioeconomic development and the impact of natural disasters: some empirical evidences from China

Significant advancements have been made in examining the relationship between economic development and disaster losses at the global and national scales, but very little research has been done at the sub-national level, especially in China. Based on socioeconomic and disaster impact data from 31 provinces (municipalities, and autonomous regions) in China from 1990 to 2010, ordinary least squares regression was used to determine the relationship between socioeconomic development and effects of natural disasters. Results showed that economic development played a distinct role in mitigating disaster damages in the whole China and its eastern, central and western regions. There existed a U-shaped relationship between economic growth and disaster losses in the whole China and its eastern region, and an inverted-U nonlinearity linkage in its central and western areas. These findings further confirmed the existence of a nonlinear relationship between economic development and disaster losses. Economic growth had played a more important role in mitigating disaster losses in the central region of China than that in the western one. Further investigations demonstrated that as economic develops, there were fewer deaths caused by natural hazards in whole China and all its three regions. The combination of the lower level of education, higher unemployment rate and greater gross dependence ratio has contributed to the increase in death toll caused by natural disasters, but this trend could be partly offset by wealth growth.     

Transboundary hazard risk: the Gobi desert paradigm

Transboundary hazard risk reflects how different societies interact with disaster in a shared landscape. In the Gobi desert of northern China and southern Mongolia recurring drought, extreme cold, wind and dust storms are the dominant hazards yet disasters vary significantly in the two countries. Research examined national approaches to environmental engagement and livelihoods in the desert through an assessment of disaster risk in two Gobi communities; farmers in Gansu Province, China, and herders in Dundgov and Omnogov Provinces, Mongolia. Exposure and resilience was evaluated and work examined how risk factors are shaped by policy, economics, culture and social memory. Comparison between two state systems reveals how disaster risk and vulnerability are shaped as much by human action as by the physical climatic event. China stressed government-led disaster management whilst Mongolia emphasised adaptation to hazards. Integrating multiple divisions within a hazard zone is essential to address risk reduction; without this disaster mitigation remains state-specific and lacks applicability to a wider area or global context.     

Investigation of ionospheric TEC precursors related to the M7.8 Nepal and M8.3 Chile earthquakes in 2015 based on spectral and statistical analysis

The assessment of social vulnerability is a requirement for understanding the risk of natural hazards. This paper calculates the social vulnerability index of geological disasters in China with the super-efficiency DEA (data envelopment analysis) model, carries out global and local autocorrelation tests for social vulnerability to geological disasters in each province in China and identifies the characteristics of its spatial distribution pattern. The results show the following. (1) China’s social vulnerability to geological disasters is relatively high and has obvious differences. It represents the pattern of a significant increase by degrees in social vulnerability to geological disasters from east to west and a significantly negative correlation relationship between the vulnerability level and the economic level. (2) Based on the comparative analysis of the mean values of the indexes and the social vulnerability index of geological disasters, it is found that the social vulnerability index of geological disasters in China is directly related to the regional exposure degree and reaction and recovery ability, among which the reaction and recovery ability has great effects on the social vulnerability index. (3) Most of the regions in China are in a high–high clustering area or a low–low clustering area; that is to say, the regions with similar social vulnerability to geological disasters represent the pattern of clustering.     

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。     

Megacities and natural disasters: a comparative analysis*

Natural disasters are a worsening problem in many of the world's largest cities. Since an increasing majority of the world's population will soon live in cities, and mostly in large cities, the trend towards increasing urban hazard poses serious societal challenges for the future. Beginning in the mid-1990s, the International Geographical Union's Study Group on the Disaster Vulnerability of Megacities undertook a series of case studies of megacities that have been – and are – exposed to major natural disasters. These include: Tokyo, Seoul, Sydney, Lima, Mexico City, Los Angeles, San Francisco, Miami, London and Dhaka. Case studies focused on reviewing the historic record of major disasters in each city and on documenting recent changes in different components of hazard including, risk, exposure, vulnerability and response. It was found that exposure and vulnerability are the components of hazard that are changing fastest and with the gravest implications for urban populations. Because hazards are only one part of the typical urban management agenda, hazards management in large cities should be pursued with careful regard to the context of general urban policy manking and management. Sustainability has become a guiding principle of urban management but the relationship between hazard and sustainability is little understood and little explored. The way lies open for hazard researchers to develop alternative contextualized approaches to the analysis and resolution of urban hazard issues. This revised version was published online in July 2006 with corrections to the Cover Date.     

中国城市主要自然灾害风险评价研究

本文依据灾害系统理论和中国自然灾害数据库,构建了反映城市承灾体的综合城市化水平（CL）指标,并在此基础上得到城市脆弱性水平指数。考虑对城市具有结构性破坏和易于造成交通灾情的主要灾种,即水灾、地震、滑坡—泥石流、台风、沙尘暴,构建了反映城市主要致灾因子的综合自然灾害强度（QC）指标,并得到城市综合自然灾害强度指数。据此,在定性分析的基础上,通过半定量计算,将中国城市主要自然灾害风险划分为高风险、较高风险、中等风险、较低风险、低风险5个等级,编制了中国城市自然灾害风险评价图,并对灾害链的综合风险评价作了进一步的探讨。     

Integrated risk zoning of drought and waterlogging disasters based on fuzzy comprehensive evaluation in Anhui Province,China

This study presents a methodology for risk analysis, assessment, combination, and regionalization of integrated drought and waterlogging disasters in Anhui Province, which is supported by geographical information systems (GIS) and technique of natural disaster risk assessment from the viewpoints of climatology, geography, disaster science, environmental science, and so on. Along with the global warming, the occurrences of water-related disasters become more frequent and serious. It is necessary to determine the mode of spatial distribution of water-related disaster risk. Based on the principle of natural disaster risk, natural conditions, and socioeconomic situation, drought and waterlogging disaster risk index, which combined hazard, exposure, vulnerability, and restorability, was developed by using combined weights, entropy, and fuzzy comprehensive evaluation method. Drought and waterlogging disaster risk zoning map was made out by using GIS spatial analysis technique and gridding GIS technique. It was used for comparing the relative risk of economic and life losses in different grids of Anhui Province. It can also be used to compare the situation of different levels of drought and waterlogging disaster combination risk in a similar place. The result shows that the northwestern and central parts of Anhui Province possess higher risk, while the southwestern and northeastern parts possess lower risk. The information obtained from statistical offices and remote sensing data in relation to results compiled were statistically evaluated. The results obtained from this study are specifically intended to support local and national governmental agencies on water-related disaster management.     

Integrated risk assessment of flood disaster based on improved set pair analysis and the variable fuzzy set theory in central Liaoning Province,China

This study presents the methodology and procedure for risk assessment of flood disasters in central Liaoning Province, which was supported by geographical information systems (GIS) and technology of natural disaster risk assessment. On the basis of the standard formulation of natural disaster risk and flood disaster risk index, of which weights were developed using combined weights of entropy, the relative membership degree functions of variable fuzzy set (VFS) theory were calculated using improved set pair analysis, while level values were calculated using VFSs, including hazard levels, exposure levels, vulnerability levels and restorability levels, and the flood risk level for each assessment unit was obtained using the natural disaster index method. Consequently, integrated flood risk map was carried out by GIS spatial analysis technique. The results show that the southwestern and central parts of the study area possess higher risk, while the northwestern and southeastern parts possess lower risk. The results got by the assessment model fits the area of historical flood data; this study offer new insights and possibility to carry out an efficient way for flood disaster prevention and mitigation. The study also provides scientific reference in flood risk management for local and national governmental agencies.     

三峡库区沿江城镇地质灾害风险评价——以重庆市万州区大周镇为例

针对三峡水利枢纽工程建成蓄水后,涉水新型城镇建设面临的地质灾害及其风险定量评价难问题,在地质灾害精细化调查基础上,以重庆市万州区大周镇集镇区为例,通过分析计算地质灾害的发育特征、稳定性和危害性,构建了基于斜坡单元的危险性评价和基于危险源分析的承灾体易损性评价的城镇尺度地质灾害风险评价框架。定量计算不同重现期降雨极值情景下的斜坡稳定性和不同灾害强度下承灾体易损性,实现了库区集镇区地质灾害风险评价; 基于社会经济发展和地质灾害风险现状分析,提出了大周镇集镇区国土空间规划建议。地质灾害风险评价结果对制定地方发展规划具有指导意义,评价方法对同类沿江城镇地质灾害风险评价具有参考价值。