Experimental research on the effect of slope morphology on bank collapse in mountain reservoir

Farmers along the Amazon River each year face multiple natural hazards that threaten crop production and limit the potential for agricultural development of the expansive floodplain and active channel. In this paper we report the findings of a study of natural hazard-related risk associated with rice production on silt bars in the active channel of the Amazon River near Iquitos, Peru. Data were gathered in four rice producing communities in 2014 using household surveys (n = 83 households), focus group discussions, surveying of land elevations along the Amazon River, and interpretation of remote sensing imagery. The probability, extent, and severity of rice crop shortfalls were estimated for recent production years and the economic losses to farming households were also assessed. Our findings point to a very high risk of crop shortfalls due to natural hazards, suggesting that a good year brings rice farmers bounty and a bad year, near penury. River stage reversals (repiquetes) and edaphic conditions were found to be more problematic than the often cited hazard of high and/or early floods. Also surprisingly, farmers’ perceptions of hazards and risk diverged markedly from actual shortfalls experienced during the production years studied. Our results provide the first quantitative estimates of risk due to the multiple natural hazards along the Amazon River and point to the need to assist lowland farmers with risk mitigation so as to unlock the considerable potential of Amazon floodlands for agricultural production.     

Emotional and cognitive factors influencing flood preparedness in Dire Dawa town,Ethiopia

Traditional approaches to risk communication ignore the emotional, cognitive and social factors that interact to influence the meaning people attribute to hazards and protective actions. The aim of this study was to investigate the emotional and cognitive factors predicting preparedness intention and community’s preparedness for flood hazards. A cross-sectional study was conducted between June and July 2015, in Dire Dawa town, Ethiopia. Using stratified systematic random sampling, a structured questionnaire was administered to individuals aged 18 and over in 660 households. Data were analyzed using structural equation modeling (SEM) (STATA version 13.0). The study participants’ mean age was 34 years, ranging from 18 to 80 (SD?=?12) with equal gender balance. SEM analysis revealed that the total effects of preparedness intention (path coefficient (β)?=?0.202, 95% CI: [0.036, 0.369]), past flood disaster experience (β?=?0.034, 95% CI: [0.008, 0.061]), trust (β?=?0.100, 95% CI: [0.059, 0.142]), anxiety (β?=?0.026, 95% CI: [0.018, 0.034), positive outcome expectancy (β?=???0.139, 95% CI: [??0.253, ??0.026]), negative outcome expectancy (β?=?0.105, 95% CI: [0.062, 0.149]), perceived flood likelihood (β?=?0.049, 95% CI: [0.012, 0.086]) and consequence (β?=???0.040, 95% CI: [??0.077, ??0.003]) on community preparedness for flood hazards were statistically significant. The main implication of these findings is that people affected by hazard events in the past experience more anxiety and are more likely to participate in community preparedness activities than those who were not affected.     

Influences of place characteristics on hazards, perception and response: a case study of the hazardscape of the Wellington Region, New Zealand

The biophysical characteristics of a place not only bring variations in natural hazards, but also influence people??s associated perception and response to the hazard. Although these influences are noted in the literature, their relationship has been less explored for planning hazard mitigation and disaster response. This paper evaluates the role of place in a hazardscape by using a case study of the Wellington Region, New Zealand. The study explores the differences between the physical and perceived susceptibility to natural hazards and how this affects people??s response to a hazard. The analysis is based on a questionnaire survey and interviews conducted with local people. It finds that disparities between physical and perceived hazard susceptibility engender different motivations and types of response. A close alignment of the two produces a high response rate for earthquakes and droughts, whereas a significant divergence leads to a poor response as observed for volcanic ash fall. The relationship, however, is not linear, as indicated by the poor response even to such well-perceived hazards as tsunami and bushfire. The reasons behind this uneven response can be related back to place characteristics, such as the nature of hazard susceptibility, as well as factors such as fatalism or blasé effect. It is concluded that mapping physical and perceived susceptibility to hazards over space, understanding their relationship and ultimately narrowing the gap between perception and reality can contribute to effective hazard management at a place.     

A conceptual model of avalanche hazard

This conceptual model of avalanche hazard identifies the key components of avalanche hazard and structures them into a systematic, consistent workflow for hazard and risk assessments. The method is applicable to all types of avalanche forecasting operations, and the underlying principles can be applied at any scale in space or time. The concept of an avalanche problem is introduced, describing how different types of avalanche problems directly influence the assessment and management of the risk. Four sequential questions are shown to structure the assessment of avalanche hazard, namely: (1) What type of avalanche problem(s) exists? (2) Where are these problems located in the terrain? (3) How likely is it that an avalanche will occur? and (4) How big will the avalanche be? Our objective was to develop an underpinning for qualitative hazard and risk assessments and address this knowledge gap in the avalanche forecasting literature. We used judgmental decomposition to elicit the avalanche forecasting process from forecasters and then described it within a risk-based framework that is consistent with other natural hazards disciplines.     

Interaction between risk perception and sense of place in disaster-prone mountain areas: a case study in China’s Three Gorges Reservoir Area

Residents of rural mountain settlements are constantly threatened by disasters such as landslides. Their risk perception directly or indirectly affects their behavioral choices. Introducing the concept of sense of place, this paper details its interactions with the risk perception of mountain hazards. Rural residents (n = 348) in landslide-threatened areas of the Three Gorges Reservoir Area were questioned about their sense of place and risk perception. Partial least squares structural equation modeling was used to explore the interactions between various dimensions, and hypothetical tests were conducted. We found that dimensions of risk perception, such as Possibility and Unknown, had direct, negative impacts on the dimensions of sense of place, such as Society bond and Place dependence. Possibility had an indirect, yet more significant effect on Place attachment and Place identity, acting through Society bond. Rural residents often overestimate disaster risks due to fatalism, and a fear of the unknown stemming from low scientific literacy, which reduces their Place dependence. A complex interaction between sense of place and risk perception was observed. The findings provide a scientific basis for the government to formulate integrated policies regarding settlement relocation, disaster prevention and mitigation, and sustainable development.     

Understanding the vulnerability of migrants in Shanghai to typhoons

China has experienced considerable migration from inland to coastal areas since the reforms of 1978, with migrants becoming an important population in many coastal cities. Compared with non-migrants (long-term residents), migrant vulnerability to typhoons is considered high due to limited access to job opportunities, social security, information, and other resources; however, there is no research on vulnerability of this population sector to natural hazards. This initial study analysed the perceptions and personal experiences of migrants living in Shanghai of typhoon hazards. During May 2010, empirical data were collected using an online questionnaire and face–face interviews. Response data indicated that risk knowledge of migrants was significantly lower than among non- migrants; differing risk perceptions between the groups were consistent with levels of personal typhoon experience; statistically significant differences in hazard knowledge within the sample also related to education and occupation; a variety of strategies to cope with typhoon hazards was being applied by residential committees; and that migrants were not generally recognised as a vulnerable group requiring special consideration in hazard risk management. To reduce the vulnerability of migrants to typhoons, we recommend expanding the range of accessible communication technologies distributing warning information; organising more educational and training programmes, at government and corporate level, to increase community awareness of natural hazards; encouraging local residential committees to promote social networks and engagement for migrants; and providing corporate incentives to develop insurances specifically for migrant needs. Further research is necessary to assess the differences in vulnerability between different types of migrants.     

Natural hazards in British Columbia: an interdisciplinary and inter-institutional challenge

 Although British Columbia experiences many natural hazards, there is as yet no unified policy to promote natural hazard management in the province. The problem is not in the quantity and quality of geoscience assessment of natural hazards, but instead, it is suggested, in the isolation of that work from broader risk perspectives and in the lack of clarity of division of responsibilities between various levels of government. The example of recent changes in perception of the terrain stability problem illustrates how natural hazard problems are driven by social and political priorities rather than by geoscience priorities. Received: 22 November 1998 / Accepted: 22 November 1998     

Risk perception and hazard mitigation in the Yangtze River Delta region,China

The Yangtze River Delta region is an area highly vulnerable to flooding. As the population density is rising concomitantly with high economic growth, this region is becoming more vulnerable to natural hazards. We conducted a survey to investigate the individual risk perception of both the local authorities and the general community, analyze the current situation regarding risk management and identify problems in the current risk management scheme. Data were collected through questionnaires distributed to some members of the community and interviews with representatives of the local authorities. The primary findings are as follows: (1) risk and disaster multipliers perceived by lay people show the stigma effect of the Wenchuan earthquake; (2) the responses of college students illustrate that the stigma effect has less influence on people who have more knowledge about hazards; (3) differences exist in comparative groups (China and USA), which shows that the society and culture influence people’s perception of risk; and (4) economic activities have complicated flood risk management such as land shortage, ground subsidence and flood diversion. Accordingly, the following measures should be taken: (1) the government should improve the risk communication and education of lay people; (2) the government must also control unsuitable land use and balance economic development and risk management; (3) flood diversion areas should be compensated through special funds collected from other cities; and (4) local governments should provide more support for hazard mitigation.     

Herders and hazards: covariate <Emphasis Type="Italic">dzud</Emphasis> risk and the cost of risk management strategies in a Mongolian subdistrict

Studies of mobile pastoralist livelihoods have shown that a variety of socio-technical practices have been developed to achieve reliable outputs from livestock in variable arid and semi-arid environments. This paper builds upon the concept of pastoralists as high-reliability seekers rather than risk-averse and makes a case for understanding Mongolian herders as well adapted to livestock production in highly variable climatic conditions within a certain threshold of risk and uncertainty. This system fails, however, during instances of high uncertainty and covariate risk such as in cases of the natural hazard dzud, which requires individual households to make significant cash investments in risk management. It forwards the idea that investing in local government—soum and bag level—administrative capacity and infrastructure is needed to build system resilience to covariate risk. Based on ethnographic research in rural Bayankhongor, this paper interrogates how dzud interfaces with socio-economic factors amongst pastoralists in central west Mongolia.     

Stakeholders’ perception in identification of river bank erosion hazard: a case study

Hazards due to riverbank erosion, despite being considered usually as a natural phenomenon, have become a critical problem in recent times as introduction of new technology and one-sided engineering-based solution approach to combat natural hazards without taking into account of opinions of all categories of stakeholders, particularly of the hazard victims and policy makers, has aggravated the problem in many cases. The riverbank erosion hazard aggravated as a direct consequence of construction of Farakka Barrage on its upstream and downstream on the river Ganga has seriously affected the lifestyles of the people in the districts of Malda and Murshidabad in the state of West Bengal in India. In this paper, an attempt has been made to study the perceptions of different groups of stakeholders, particularly hazard victims and authority responsible for monetary investment, about causes of riverbank erosion and possible preventive and remedial measures required to solve such a complex and multi-dimensional problem. A questionnaire-based household survey has been conducted on a number of important issues of the problem among the directly affected hazard victims at a highly erosion-prone area in the Malda district. Different perceptions and their impacts on selection and implementation of anti-erosion measures are critically studied. Analysis of data as obtained from the representative sample of erosion victims as well as the secondary sources of data clearly indicates that the hazard victims are to face bad effects because of existence of perception gap and that a holistic approach considering the perception of erosion victims needs to be undertaken for a permanent solution of the problem.     

Probabilistic seismic hazard assessment in the Constantine region,Northeast of Algeria

This paper presents a seismic hazard evaluation and develops an earthquake catalogue for the Constantine region over the period from 1357 to 2014. The study contributes to the improvement of seismic risk management by evaluating the seismic hazards in Northeast Algeria. A regional seismicity analysis was conducted based on reliable earthquake data obtained from various agencies (CRAAG, IGN, USGS and ISC). All magnitudes (M _l, m _b) and intensities (I ₀, I _MM, I _MSK and I _EMS) were converted to M _s magnitudes using the appropriate relationships. Earthquake hazard maps were created for the Constantine region. These maps were estimated in terms of spectral acceleration (SA) at periods of 0.1, 0.2, 0.5, 0.7, 0.9, 1.0, 1.5 and 2.0 s. Five seismogenic zones are proposed. This new method differs from the conventional method because it incorporates earthquake magnitude uncertainty and mixed datasets containing large historical events and recent data. The method can be used to estimate the b value of the Gutenberg-Richter relationship, annual activity rate λ(M) of an event and maximum possible magnitude M _max using incomplete and heterogeneous data files. In addition, an earthquake is considered a Poisson with an annual activity rate λ and with a doubly truncated exponential earthquake magnitude distribution. Map of seismic hazard and an earthquake catalogue, graphs and maps were created using geographic information systems (GIS), the Z-map code version 6 and Crisis software 2012.     

Probabilistic seismic hazard analysis of Kahramanmaras Province,Turkey

Kahramanmaras and its surroundings are under the influence of East Anatolian and Dead Sea fault zones which have significance in the tectonics of Turkey. The long-term energy accumulation in these zones creates a very high risk level in terms of seismic hazard. In this study, the seismic hazard of Kahramanmaras Province and its vicinity was tried to be determined by using the probabilistic seismic hazard method approach. The earthquake catalog used in the study comprises 424 earthquakes equal or greater than M _w ?=?4.0, covering a time period between 1 January 1900 and 1 January 2015. The earthquake data have been compiled from the catalogs of the International Seismological Center (ISC), Republic of Turkey Prime Ministry Disaster and Emergency Management Precidency (RTPMDEMP), Bogazici University Kandilli Observatory and Earthquake Research Institute. Seismic sources that could affect the study area have been identified according to the Earthquake Model of the Middle East (EMME). Seismic hazard parameters and peak horizontal acceleration values were obtained by using the selected attenuation relationships, and the results were given with iso-acceleration maps corresponding to a recurrence period of 475 years. The calculated peak horizontal acceleration values are generally varying between 0.21 and 0.41 in the study area. The result of this study shows that the southeastern parts of the study area have a greater seismic hazard compared with other parts.     

Uncertainties in the estimation of <Emphasis Type="Italic">M</Emphasis><Subscript>max</Subscript>

In the present paper, the parameters affecting the uncertainties on the estimation of M _max have been investigated by exploring different methodologies being used in the analysis of seismicity catalogue and estimation of seismicity parameters. A critical issue to be addressed before any scientific analysis is to assess the quality, consistency, and homogeneity of the data. The empirical relationships between different magnitude scales have been used for conversions for homogenization of seismicity catalogues to be used for further seismic hazard assessment studies. An endeavour has been made to quantify the uncertainties due to magnitude conversions and the seismic hazard parameters are then estimated using different methods to consider the epistemic uncertainty in the process. The study area chosen is around Delhi. The b value and the magnitude of completeness for the four seismogenic sources considered around Delhi varied more than 40% using the three catalogues compiled based on different magnitude conversion relationships. The effect of the uncertainties has been then shown on the estimation of M _max and the probabilities of occurrence of different magnitudes. It has been emphasized to consider the uncertainties and their quantification to carry out seismic hazard assessment and in turn the seismic microzonation.     

Probabilistic Tsunami Hazard Assessment (PTHA) for resilience assessment of a coastal community

Probabilistic Tsunami Hazard Analysis (PTHA) can be used to evaluate and quantify tsunami hazards for planning of integrated community-level preparedness, including mitigation of casualties and dollar losses, and to study resilient solutions for coastal communities. PTHA can provide several outputs such as the intensity measures (IMs) of the hazard quantified as a function of the recurrence interval of a tsunami event. In this paper, PTHA is developed using a logic tree approach based on numerical modeling for tsunami generated along the Cascadia Subduction Zone. The PTHA is applied to a community on the US Pacific Northwest Coast located in Newport, Oregon. Results of the PTHA are provided for five IMs: inundation depth, flow speed, specific momentum flux, arrival time, and duration of inundation. The first three IMs are predictors of tsunami impact on the natural and built environment, and the last two are useful for tsunami evacuation and immediate response planning. Results for the five IMs are presented as annual exceedance probability for sites within the community along several transects with varying bathymetric and topographic features. Community-level characteristics of spatial distribution of each IM for three recurrence intervals (500, 1000, 2500 year) are provided. Results highlight the different pattern of IMs between land and river transects, and significant magnitude variation of IMs due to complex bathymetry and topographic conditions at the various recurrence intervals. IMs show relatively higher magnitudes near the coastline, at the low elevation regions, and at the harbor channel. In addition, results indicate a positive correlation between inundation depth and other IMs near the coastline, but a weaker correlation at inland locations. Values of the Froude number ranged 0.1–1.0 over the inland inundation area. In general, the results in this study highlight the spatial differences in IMs and suggest the need to include multiple IMs for resilience planning for a coastal community subjected to tsunami hazards.     

Putting adaptive capacity into the context of people’s lives: a case study of two flood-prone communities in Puerto Rico

Recent developments in the vulnerability literature have contested the use of technical solutions as the sole adaptive strategies to reduce natural hazard impact; this literature emphasizes the need to attend to the wider everyday risks to which people are exposed and that aggravate hazard vulnerability. Using a case study of two flood-prone communities in Puerto Rico, this article supports and enhances that literature by placing floods within a wider context of other risks and determining how everyday risks influence people’s perceptions of and capacity to adapt to floods. Participatory methods are used to elicit the everyday risks that concern community members. The analysis reveals that participants perceive floods as one of their risks, but they see them as neither the most important nor most severe risk in their lives. Instead, they find other concerns—health conditions, family well-being, economic factors, and land tenure—more pressing. These competing risks limit adaptive capacity and increase vulnerability to natural hazards. The results suggest that addressing these multiple risks, mainstreaming flood management and adaptation into the wider context of people’s general well being, and increasing risk perception will strengthen adaptive capacity to present and future floods.     

Thinking outside the polygon: a study of tornado warning perception outside of warning polygon bounds

When the National Weather Service (NWS) issues a tornado warning, the alert is rapidly and widely disseminated to individuals in the general area of the warning. Historically, the assumption has been that a false-negative warning perception (i.e., when someone located within a warning polygon does not believe they have received a tornado warning) carries a higher cost than a false-positive warning perception (i.e., when someone located outside the warning area believes they have received a warning). While many studies investigate tornado warning false alarms (i.e., when the NWS issues a tornado warning, but a tornado does not actually occur), less work focuses on studying individuals outside of the warning polygon bounds who believe they received a warning (i.e., false-positive perceptions). This work attempts to quantify the occurrence of false-positive perceptions and possible factors associated with the rate of occurrence. Following two separate storm events, Oklahomans were asked whether they perceived a tornado warning. Their geolocated responses were then compared to issued warning polygons. Individuals closer to tornado warnings or within a different type of warning (e.g., a severe thunderstorm warning) are more likely to report a false-positive perception than those farther away or outside of other hazard warnings. Further work is needed to understand the rate of false-positive perceptions across different hazards and how this may influence warning response and trust in the National Weather Service.

     

Natural hazards,extreme events,and mountain topography

The hazard of any natural process can be expressed as a function of its magnitude and the annual probability of its occurrence in a particular region. Here we expand on the hypothesis that natural hazards have size–frequency relationships that in parts resemble inverse power laws. We illustrate that these trends apply to extremely large events, such as mega-landslides, huge volcanic debris avalanches, and outburst flows from failures of natural dams. We review quantitative evidence that supports the important contribution of extreme events to landscape development in mountains throughout the world, and propose that their common underreporting in the Quaternary record may lead to substantial underestimates of mean process rates. We find that magnitude–frequency relationships provide a link between Quaternary science and natural hazard research, with a degree of synergism and societal importance that neither discipline alone can deliver. Quaternary geomorphology, stratigraphy, and geochronology allow the reconstruction of times, magnitudes, and frequencies of extreme events, whereas natural hazard research raises public awareness of the importance of reconstructing events that have not happened historically, but have the potential to cause extreme destruction and loss of life in the future.     

Vulnerability assessment for preliminary flood risk mapping and management in coastal areas

Despite continuing technological advancement in hazard and vulnerability assessment, risk modelling and hazard mitigation techniques, losses to disasters associated with natural hazards continue and in some cases are increasing across Europe and worldwide. This paper focuses on the need to bridge the gap between technical solutions and the sociopolitical contexts in which these are produced, to better understand and create more effective risk management regimes. We do so with application of the science–policy co-production frame to landslide risk management in Italy. The methodology deployed included a desk study informed by semi-structured interviews carried out with selected key stakeholders at national, regional and municipal level. We propose a normative and analytical framework for transferring co-production into natural hazard research by presenting a matrix identifying four contexts within which co-production may unfold. The matrix is based on two axes, which distinguish between innovation and its absence in science and policy domains. We examine several examples of co-production, such as the water–soil integrated approach to risk management or the implementation of hazard/risk assessment. The results highlight that the insulation of science from the institutional context within which knowledge is produced and used is a very problematic issue. This often hinders the implementation of desirable policies and undermines the effectiveness of interventions. Moreover, innovation in science and policy does not automatically result in successful solutions for landslide risk management. Finally, results confirm the utility of co-production but also highlight methodological challenges associated with the introduction of this new conceptual paradigm into the well-structured communities of scientists and policy-makers.     

Using regression model to identify and evaluate heavy metal pollution sources in an open pit coal mine area,Eastern Junggar,China

This study aims at identifying multi-source heavy metal pollution from natural and anthropogenic sources using a regression model, principal component analysis, and five different indices (geo-accumulation index (I _geo), the modified degree of contamination, pollution load index (PLI), enrichment factor, and ecological risk factor. Results revealed that: (1) although the average concentrations of soil heavy metals (Cu, Cr, Pb, Hg, As, Zn) were generally low, Hg, As, and Cr concentrations exceeded national standard values by approximately 0.91, 1.84, and 0.91 times with maximum concentrations up to 0.41, 78.6, and 175.2 μg/g, respectively; (2) PLI results showed that the industrial park and Wucaiwan open coal mining area were the most polluted (PLI of 1.98, 1.71). The potential ecological hazards index indicated that the E _i ^r of three heavy metals (Cu, Hg, As) in the soil were relatively high, presenting potential ecological risk factors of 74.89, 16.71, 4.15%, respectively; (3) stepwise regression model and principal component analysis suggest that Cu and Zn were primarily effected by the natural geological condition and atmospheric dust fall. Cr, Hg, Pb are mainly derived from anthropogenic sources, particularly coal mining activities and industrial sources. Results of this research have some significant implications for heavy metal pollution prevention and the sustainable development of the economy and ecology of arid regions in China.     

Why are flood and landslide victims less willing to take mitigation measures than the public?

Almost annually, natural hazards such as floods and landslides cause a great deal of financial loss and human suffering in Taiwan. In order to gain a better understanding of disaster preparedness, this paper examines several factors in relation to hazard mitigation behavior: social economic status (education, income), psychological vulnerability (sense of powerless and helpless), risk perception (perceived impact and control) and social trust. The statistical analysis reported here is based on the “2004 National Risk Perception Survey of Floods and Landslides in Taiwan”. The main findings include: (1) in comparison with general public, victims are less willing to adopt risk mitigation measures than the public, even though they perceive larger impacts, worry more about the hazard, and pay more attention to hazard information; (2) trust, risk perception and social economic status are positive predictors for mitigation intentions, whereas psychological vulnerability is a negative predictor; and (3) psychological variables are stronger predictors for mitigation intentions than that of socio-economic variables. In light of these findings, the policy implications and intervention strategy are also discussed.