Contextualizing social vulnerability: findings from case studies across Europe

Social vulnerability is a term that has been widely used in the natural hazards literature for quite a few years now. Yet, regardless of how scholars define the term, the approaches and indicators they use remain contested. This article presents findings from social vulnerability assessments conducted in different case studies of flood events in Europe (Germany, Italy and the UK). The case studies relied upon a common set of comparable indicators, but they also adopted a context-sensitive, qualitative approach. A shared finding across the case studies was that it was not possible to identify a common set of socio-economic–demographic indicators to explain social vulnerability of groups and/or individuals for all phases of the disastrous events. Similarly, network-related indicators as well as location- and event-specific indicators did not have the relevance we expected them to have. The results underline that vulnerability is a product of specific spatial, socio-economic–demographic, cultural and institutional contexts imposing not only specific challenges to cross-country research concerning social vulnerability to flooding but also to attempts at assessing social vulnerability in general. The study ends with some reflections upon the methodological, practical and theoretical implications of our findings.     

Backward modeling of the rifting kinematics in the Upper Rhine Graben: insights from an elastic-perfect contact law on the restoration of a multi-bloc domain

This paper addresses the problem of volume restoration for 3-D sedimentary basin kinematic deformation. The primary purpose is methodological and concerns the use of contact mechanics with the finite element method, in order to deform a geological multi-bloc domain. This approach is applied to backward model the later stage of rifting of a segment of the southern Upper Rhine Graben (France–Germany border). Preliminary results from our modeling demonstrate the ability of the method not only to handle complex geometries, but also to successfully perform retro-deformation of a complex geological domain. In addition, they provide or confirm crucial information on the rifting evolution and tectonic features of this segment of the Upper Rhine Graben, such as the distribution of deformation, the asymmetry of the graben and a significant left-lateral strike-slip component of displacement.     

An innovative micro-scale approach for vulnerability and flood risk assessment with the application to property-level protection adoptions

Economic damage assessment for flood risk estimation is established in many countries, but attentions have been focused on macro- or meso-scale approaches and less on micro-scale approaches. Whilst the macro- or meso-scale approaches of flood damage assessment are suitable for regional- or national-oriented studies, micro-scale approaches are more suitable for cost–benefit analysis of engineered protection measures. Furthermore, there remains lack of systematic and automated approaches to estimate economic flood damage for multiple flood scenarios for the purpose of flood risk assessment. Studies on flood risk have also been driven by the assumption of stationary characteristic of flood hazard, hence the stationary-oriented vulnerability assessment. This study proposes a novel approach to assess vulnerability and flood risk and accounts for adaptability of the approach to nonstationary conditions of flood hazard. The approach is innovative in which an automated concurrent estimation of economic flood damage for a range of flood events on the basis of a micro-scale flood risk assessment is made possible. It accounts for the heterogeneous distribution of residential buildings of a community exposed to flood hazard. The feasibility of the methodology was tested using real historical flow records and spatial information of Teddington, London. Vulnerability curves and residual risk associated with a number of alternative extents of property-level protection adoptions are estimated by the application of the proposed methodology. It is found that the methodology has the capacity to provide valuable information on vulnerability and flood risk that can be integrated in a practical decision-making process for a reliable cost–benefit analysis of flood risk reduction options.     

Surface heat flow and probable evolution of Deccan volcanism

In the light of surface heat-flow observations, as well as other related geological and geophysical data, the origin of the Deccan basalts has been examined. The Indian lithosphere, after its detachment from Gondwanaland, apparently traversed a rising plume at La Réunion, which virtually bored through the lithosphere to emerge as the Deccan Trap volcanism on the surface. Subsequent volcanic and plutonic activity appears to have continued not only up to the Oligocene, as is indicated by the alkaline magmatic activity observed near the junction of the three prominent features — the West Coast faults, the Narmada-Son-Tapti lineament, and the Cambay Graben — but also up to the Mio-Pliocene, as indicated by the heat flow and gravity data over the Cambay Graben. The dyke-swarms and sills, which are mostly post-trappean, evolved from the lithosphere after the Indian Plate moved away from the hot spot.     

Hydrological hazards in Russia: origin,classification, changes and risk assessment

Hydrological extreme events pose an imminent risk to society and economics. In this paper, various aspects of hydrological hazards in Russia are analysed at different scales of risk assessment. It is shown that the number of hydrological and meteorological hazards in Russia has been growing every year. The frequency of economic losses associated with extreme low flow in this century has increased by factor five compared to the last decade of the previous century. With regard to floods, an interesting spatial patter can be observed. On the one hand, the number of floods in the Asian part of the country has increased, whereas on the other hand, the number and intensity of floods in estuarine areas in the European part of Russia have significantly reduced since the middle of the twentieth century, especially in the 2000s. This decrease can be attributed to runoff flooding in the mouths of regulated rivers, with an effective system of flood and ice jam protection. The analysis shows that there is an 8–12-year periodicity in the number of flood occurrences and that flood surges have intensified over the last 110 years, especially on the European territory of Russia. An integrated index that accounts for flood hazards and socio-economic vulnerability was calculated for each region of Russia. A classification of flood risk was also developed, taking into account more than 20 hydrological and social–economic characteristics. Based on these characteristics, hazard and vulnerability maps for entire Russia were generated which can be used for water management and the development of future water resources plans.

     

白洋淀漕河全新世早期古洪水事件的沉积特征及气候背景

古洪水沉积物是研究地史时期极端降水事件和古环境演化的重要载体。基于地质记录开展古洪水重建研究,可以为揭示区域洪水历史过程及机制提供依据,对水资源利用和工程建设等具有重要的现实意义。本文以漕河古河道北岸出露较好的李迪城村剖面为研究对象,综合地层序列、野外沉积特征、沉积构造及沉积物粒度分析,对白洋淀地区漕河古河道沉积记录的古洪水事件进行了识别,发现该剖面具有以下主要特征:古洪水沉积层与下伏地层存在明显的冲刷侵蚀面,沉积体形态呈透镜状,由泥砾、炭屑、双壳类及灰黑色粉细砂混杂组成,发育中小型交错层理;洪水沉积物粒度指标(中值粒径、砂含量、黏土/粉砂值及Q90)表现为高值,以细砂为优势组分,含混杂的粉砂及少量黏土,分选较差;古洪水沉积层中古树与双壳类集中埋藏,呈定向排列,其指示的方向与遥感影像揭示的古河道方向一致。通过该剖面沉积特征及地层AMS ¹⁴C年代分析,确定漕河在全新世早期约10.8~9.6 ka BP发生了4期古洪水事件,这4期古洪水事件可以与该时期华北地区其它古洪水事件进行对比。当时正值全新世早期,东亚夏季风增强,为气温和降水频繁波动上升时期,据此推断白洋淀地区全新世早期的古洪水事件是当时气候背景下的产物。     

A simplified approach for flood vulnerability assessment of historic sites

In the last decades, floods have increased in frequency all over the world due to diverse phenomena such as climate change, extended urbanization, land use, etc. Their social, cultural, economic and environmental impacts have also grown significantly, highlighting the need for the development of further studies and improved methods to manage and mitigate flood risk, mainly in urban areas. Historic sites need particular attention in this field, not only because the high and irreplaceable cultural value of these areas, but also taking into account that the constructive typologies that they host are particularly vulnerable to natural hazards. In consequence of that, the analysis of the phenomena, the evaluation of their consequences and the adoption of adequate mitigation and preparedness measures are presently a fundamental societal challenge. Having this in mind, the present paper aims at proposing an innovative methodology focused on the assessment of flood vulnerability in historic sites through the evaluation of a set of exposure and sensitivity indicators. From the analysis of these indicators, it is possible to obtain a Flood Vulnerability Index capable of measuring the spread of flood vulnerability over an extended area. The historic centre of Guimarães, in Portugal, declared by UNESCO as a World Heritage Site in 2001, is used here as a pilot case study to apply and discusses the preliminary version of the approach. Although some improvements are still needed, this approach can be already used to provides preliminary vulnerability scenarios and to point the way to the definition of more efficient and customized strategies for managing and mitigating flood risk in historic sites. Moreover, with further improvements and calibrations resorting to larger and more diverse data, it will be possible to reduce some of the uncertainties currently involved in the assessment process and to make its application wider and more robust.

     

Urban flood vulnerability assessments: the case of Dire Dawa city,Ethiopia

Dire Dawa city is identified as one of the most flood-affected cities in Ethiopia. Classifying village-level flood vulnerability using flood indicators is a new approach to Dire Dawa city. Analysis of different flood vulnerability factors underpins sustainable flood risk management and the application of Flood Vulnerability Index (FVI) approach is the hub of this study. Relevant data were collected from 110 households sampled from purposely selected 10 villages found in Dire Dawa city. The flood vulnerability index was used to compare, classify and rank villages in terms of their flood vulnerability levels. For this purpose, 24 sets of indicators which are strongly affecting the levels of flood vulnerability were assessed from social, economic and physical perspectives. The FVI of each village was computed with unequal method of weighting indicators. The findings of the study revealed that Dire Dawa city villages were experiencing varying levels of flood vulnerability. Accordingly, villages 05, 06, 07 and 09 were identified with high flood vulnerability level while villages 03, 04 and 08 and villages 01, 02 and extension village were identified with medium and low level of vulnerability, respectively. Interestingly, the findings of the study confirmed that social factors contributed much for flood vulnerability in Dire Dawa city. Hence, future urban flood risk planning and management endeavors in the city of Dire Dawa must be underpinned by proper utilization of the flood vulnerability map developed addressing social vulnerability component through both structural and non-structural urban flood risk management measures.

     

Integration of inland and coastal storms for flood hazard assessment using a distributed hydrologic model

Due to increasing flood severities and frequencies, studies on coastal vulnerability assessment are of increasing concern. Evaluation of flood inundation depth and extent is the first issue in flood vulnerability analysis. This study has proposed a practical framework for reliable coastal floodplain delineation considering both inland and coastal flooding. New York City (NYC) has been considered as the case study because of its vulnerability to storm surge-induced hazards. For floodplain delineation, a distributed hydrologic model is used. In the proposed method, the severities of combined inland and coastal floods for different recurrence intervals are determined. Through analyzing past storms in the study region, a referenced (base) configuration of rainfall and storm surge is selected to be used for defining flood scenarios with different return periods. The inundated areas are determined under different flooding scenarios. The inundation maps of 2012 superstorm Sandy in NYC is simulated and compared with the FEMA revised maps which shows a close agreement. This methodology could be of significant value to the planners and engineers working on the preparedness of coastal urban communities against storms by providing a platform for updating inundation maps as new events are observed and new information becomes available.     

High‐resolution seismic reflection profiling of neotectonic faults in Lake Timiskaming,Timiskaming Graben,Ontario‐Quebec,Canada

The Timiskaming Graben is a 400 km long, 50 km wide north‐west trending morphotectonic depression within the Canadian Shield of eastern North America and experiences frequent intraplate earthquakes. The graben extends along the border of Ontario and Quebec, connecting southward with the Nipissing and Ottawa‐Bonnechere grabens and the St. Lawrence Rift System which includes a similar structure underlying the Hudson Valley of the eastern USA. Together they form a complex failed rift system related to regional extension of North American crust during the breakup of Rodinia and, later, Pangea. The Timiskaming Graben lies within a belt of heightened seismic activity (Western Quebec Seismic Zone) with frequent moderate magnitude (greater than magnitude 5) earthquakes including a magnitude 6.2 in 1935. These events threaten aging urban infrastructure built on soft glacial sediments; post‐glacial landslides along the Ottawa Valley suggest earthquakes as large as magnitude 7. The inner part of the Timiskaming Graben is filled by Lake Timiskaming, a large 110 km long post‐glacial successor to glacial Lake Barlow that was ponded by the Laurentide Ice Sheet 9500 years ago. The effects of frequent ground shaking on lake floor sediments was assessed by collecting more than 1000 line kilometres of high‐resolution ‘chirp’ seismic profiles. Late glacial Lake Barlow glaciolacustrine and overlying post‐glacial sediments are extensively deformed by extensional faults that define prominent horsts and grabens; multibeam bathymetry data suggest that faults influence the morphology of the modern lake floor, despite high sedimentation rates, and indicate recent neotectonic deformation. The Lake Timiskaming area provides evidence of post‐glacial intracratonic faulting related to recurring earthquake activity along a weak spot within the North American plate.     

Social and economic vulnerability of coastal communities to sea-level rise and extreme flooding

This paper assesses the socioeconomic consequences of extreme coastal flooding events. Wealth and income impacts associated with different social groups in coastal communities in Israel are estimated. A range of coastal flood hazard zones based on different scenarios are identified. These are superimposed on a composite social vulnerability index to highlight the spatial variation in the socioeconomic structure of those areas exposed to flooding. Economic vulnerability is captured by the exposure of wealth and income. For the former, we correlate the distribution of housing stock at risk with the socioeconomic characteristics of threatened populations. We also estimate the value of residential assets exposed under the different scenarios. For the latter, we calculate the observed change in income distribution of the population under threat of inundation. We interpret the change in income distribution as an indicator of recovery potential.     

Vulnerability assessments and their planning implications: a case study of the Hutt Valley, New Zealand

An understanding of vulnerability is not only crucial for the survival of the exposed communities to extreme events, but also for their adaptation to climate change. Vulnerability affects community participation in hazard mitigation, influences emergency response and governs adaptive capacity for the changing environmental and hazards characteristics. However, despite increased awareness, assessments and understanding of the processes that produce vulnerability, disaster risks prevail. This raises questions on the effectiveness of vulnerability assessments and their applications for hazard mitigation and adaptation. The literature includes a range of vulnerability assessment methods, wherein frequently the selection of any particular method is governed by the research objectives. On the other hand, hazard mitigation plans and policies even though mention vulnerability, their implementation pays less attention to the variations in its nature and underlying causes. This paper explores possible reasons for such gaps by exploring a case study of the Hutt Valley, New Zealand. It brings out the limitations of different vulnerability assessment methods in representing the local vulnerability and challenges they bring in planning for the vulnerability reduction. It argues that vulnerability assessment based on any particular method, such as deprivation index, principle component analysis, composite vulnerability index with or without weight, may not reveal the actual vulnerability of a place, and therefore, a comprehensive vulnerability assessment is needed.     

Coastal flooding in the Maldives: an assessment of historic events and their implications

With many inhabited islands only at about 1 m above mean sea level, the Maldives is among the nations most threatened by coastal flooding and sea level rise. However, the understanding of recent coastal flood events in the Maldives is limited and is important to understanding future flood threats. This paper assesses (1) the sea level and wave climate of the Maldives, (2) the sea level and wave conditions during recent coastal flood events, and (3) the implications for flood management and future research. The analysis uses observed still water levels (1987–2015) and hindcast wave conditions (1979–2015). Two significant flood events on 10–13 April 1987 and 15–17 May 2007 are examined in detail. This shows that coastal flooding in the Maldives occurs due to multiple interacting sources. These include long-period (up to 20 s) energetic waves generated in the Southern Ocean combined with spring tides. Wave run-up (mainly wave set-up) appears an essential mechanism for a flood, but is currently poorly quantified. However, as sea levels continue to rise the conditions that produce a flood will occur more frequently, suggesting that flooding will become common in the Maldives. This analysis is a starting point for future research and highlights the need to continue research on flood sources, pathways and receptors, and plan adaptation measures. Priorities include monitoring of waves, sea levels and flood events, and a better understanding of set-up (and other shallow water processes over reefs).     

南海西北与西南次海盆沉积通量及其控制因素

作为西太平洋陆源沉积"源-汇"过程的重要场所,南海海盆半封闭的构造环境使得其与开放大洋的物质交换十分有限,沉积物保存基本完整,可以建立起南海沉积过程与区域重大构造事件、气候变化、海平面变化等之间的系统联系.选取南海西南与西北两个次海盆为对比研究区,基于穿越海盆的高分辨率多道地震测线和国际大洋发现计划(International Ocean Discovery Program,简称IODP)在南海获取的钻井数据,井震结合划分沉积单元,计算不同地质历史时期沉积通量,从而对海盆的沉积过程进行半定量化约束,并对控制因素和可能物源进行探讨.结果表明:南海西北次海盆和西南次海盆深海盆区的沉积过程整体上受到大型构造事件(青藏高原隆升-剥蚀作用)、东亚季风演化、陆缘水系(珠江、湄公河等)发展和相对海平面变化的控制,但在不同的区域会由于所处地理位置不同,以及局部构造事件影响而变得复杂化,从而使得西北次海盆与西南次海盆沉积通量在相同的地质时期呈现出不同的特征.西北次海盆沉积物主要源自华南大陆,并有少量来自红河、海南岛、北部陆架区局部隆起(如东沙隆起)的贡献.而西南次海盆的沉积物在晚中新世之前主要来自印支半岛、南沙地区和巴拉望,而在之后主要来自于现代湄公河.      

Rhine flood deposits recorded in the Gallo-Roman site of Oedenburg (Haut-Rhin, France)

From the first to the fourth century AD, the Gallo-Roman town of Oedenburg developed in the alluvial landscape of the southern Upper Rhine Graben. Throughout this period, the landscape mosaic, composed of palaeochannels, stable palaeoislands and river terraces, continued to evolve. A district of this town, situated on a lateral Rhine channel system, was archaeologically excavated. Large-scale excavation and cross-section analysis provide evidence of changing fluvial conditions during the period under study. At about AD 20 or earlier, this lateral part of the floodplain, affected by very fine sedimentation, was occupied by moribund marshy palaeochannels. When the first Gallo-Roman settlers occupied the site, they filled parts of the channels with woven brushwood in order to create an efficient circulation surface. The sedimentary infill of this palaeochannel records four different flood deposits interlayered with dated anthropogenic units (pavements, road embankments, and other structures). Archaeological analysis and dendrochronological dating indicate that these four flooding events occurred during a short time period between AD 20 and AD 145/146. These geoarchaeological observations focus on floods that do not seem to have significantly affected human occupation in this part of the Rhine floodplain. These results are set in the broader context of the Rhine catchment and the Alps.     

鞍山市铁矿矿山地质灾害形成条件及对策研究

矿山地质灾害较其它地质灾害相比有其独特性。在鞍山铁矿区，排土场沉降不仅与采矿引起的地下水位下降有直接的联系，还与松散细粒土层、活动断裂有关；滑坡、泥石流地质灾害与地形地貌、水源条件及构造有一定的关系，更重要的是采矿活动产生的废石废渣为其提供了大量的物源；尾矿库灾害主要表现为：洪水漫顶、尾矿砂液化破坏、尾矿坝渗漏及管涌溃堤、尾矿坝滑塌破坏等。本文简要分析了鞍山市铁矿山主要存在的地质灾害类型(排土场地面沉降、滑坡、泥石流及尾矿库地质灾害)和形成条件并提出了防治地质灾害的对策。     

Flooding and the Midwest economy: assessing the Midwest floods of 1993 and 2008

This paper examines local economic vulnerability over time by comparing how county-level unemployment rates were affected by two major flooding events in the Midwest region, one in 1993 and the other in 2008. One of the challenges for studies of this kind is to separate out the impact of the hazard events from the effects of more general macroeconomic dynamics. A case–control design is used in the analysis for that purpose, applying an optimal matching algorithm to select a non-flooded control county for each flooded case county and then model the flood effects using ARIMA intervention models. The main research finding of this study is that the 1993 flood affected a larger area and caused more severe economic disturbances than the 2008 flood. Counties that were hit hard in 1993 seemed to fare well in 2008. It was also found that higher damage was associated with an increase in the county-level unemployment rate.     

Coastal inundation and damage exposure estimation: a case study for Jakarta

Coastal flooding poses serious threats to coastal areas, and the vulnerability of coastal communities and economic sectors to flooding will increase in the coming decades due to environmental and socioeconomic changes. It is increasingly recognised that estimates of the vulnerability of cities are essential for planning adaptation measures. Jakarta is a case in point, since parts of the city are subjected to regular flooding on a near-monthly basis. In order to assess the current and future coastal flood hazard, we set up a GIS-based flood model of northern Jakarta to simulate inundated area and value of exposed assets. Under current conditions, estimated damage exposure to extreme coastal flood events with return periods of 100 and 1,000 years is high (€4.0 and €5.2 billion, respectively). Under the scenario for 2100, damage exposure associated with these events increases by a factor 4–5, with little difference between low/high sea-level rise scenarios. This increase is mainly due to rapid land subsidence and excludes socioeconomic developments. We also develop a detemporalised inundation scenario for assessing impacts associated with any coastal flood scenario. This allows for the identification of critical points above which large increases in damage exposure can be expected and also for the assessment of adaptation options against hypothetical user-defined levels of change, rather than being bound to a discrete set of a priori scenarios. The study highlights the need for urgent attention to the land subsidence problem; a continuation of the current rate would result in catastrophic increases in damage exposure.     

新疆阿克苏河流域洪水演变趋势研究

全球气候变暖将加剧水循环,增大洪水风险。阿克苏河流域位于天山南坡,是北半球中纬度典型的高山流域。本流域不仅有暴雨洪水、冰川和积雪融水造成的洪水,而且还有冰川溃决突发洪水。以阿克苏河的两条支流库玛拉克河和托什干河为研究对象,利用块最大值抽样方法（block maximum）和超定量阈值（peak over threshold,POT）抽样方法提取出1958—2011年的洪水事件,其中基于POT方法在两条支流分别提取106次和112次洪水事件,主要集中在6月、7月和8月份。研究表明：阿克苏河的两条支流库玛拉克河和托什干河的年最大洪水强度分别以8.48 m³?s^-1和3.40 m³?s^-1的速率增加;在洪水发生时间上,以冰川融水补给为主的库玛拉克河,洪水发生时间有提前的趋势,而以降雨和融雪水补给为主的托什干河,洪水发生时间变得更加分散,表现为春季最大洪水提前、秋季最大洪水推后。