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Natural Hazards (natural + hazard)

Distribution by Scientific Domains

Humanities and Social Sciences	35%
Engineering	29%
Earth and Environmental Science	29%

Selected Abstracts

Typology of Natural Hazards and Assessment of Associated Risks in the Mount Bambouto Caldera (Cameroon Line, West Cameroon)

ACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 5 2009
Ghislain T. ZANGMO
Abstract: Mount Bambouto is a polygenic stratovolcano of the Cameroon Volcanic Line, built between 21 Ma and 4.5 Ma. It is situated approximately 200 km NE of Mount Cameroon, between 09° 55, and 10°15, longitude east and, 05°25, and 05°50, latitude north. The volcano covers an area of 500 km2 and culminates at 2740 m at Mélétan dome and bears a collapsed caldera at the summit (13 × 8 km). Mount Bambouto is characterized by several natural hazards of different origins: meteorological, such as landslides and rock falls; anthropogenic, such as bushfires, tribal wars and deforestation; and volcanological, such as volcanic eruption. The thematic map shows that 55,60% of the caldera has high probability of occurrence of mass movement. The caldera has a high population density (3000 inhabitants), which increases the level of risk, evaluated at approximately $US3.8 million for patrimony, 3000 civilian deaths and destruction of biodiversity. [source]

TOWARDS CHARACTERIZING AND PLANNTNG FOR DROUGHT IN VERMONT-PART II: POLICY IMPLICATIONS,

JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 3 2001
Lesley-Ann Dupigny-Giroux
ABSTRACT: Vermont is one of approximately half a dozen states for which no official drought mitigation plan exists. Given the recurring nature of this natural hazard, current contingency measures should be expanded upon into a coherent mitigation framework. The types of drought and impacts resulting from the 1998 to 1999 event were the focus of a previous article in this volume. The present article builds on the understanding of drought characteristics specific to the Vermont context and introduces the rationale behind a proposed drought planning framework. Pivotal organizations and institutions that should be involved in this process are also presented. [source]

Combating drought through preparedness

NATURAL RESOURCES FORUM, Issue 4 2002
Donald A. Wilhite
Drought is a complex, slow,onset phenomenon that affects more people than any other natural hazard and results in serious economic, social, and environmental impacts. Although drought affects virtually all climatic regimes and has significant consequences in both developed and developing countries, its impacts are especially serious in developing countries where dryland agriculture predominates. The impacts of drought are often an indicator of unsustainable land and water management practices, and drought assistance or relief provided by governments and donors encourages land managers and others to continue these practices. This often results in a greater dependence on government and a decline in self,reliance. Moving from crisis to risk management will require the adoption of a new paradigm for land managers, governments, international and regional development organizations, and non,governmental organizations. This approach emphasizes preparedness, mitigation, and improved early warning systems (EWS) over emergency response and assistance measures. Article 10 of the Convention to Combat Desertification states that national action programmes should be established to identify the factors contributing to desertification and practical measures necessary to combat desertification and mitigate the effects of drought. In the past 10 years, there has been considerable recognition by governments of the need to develop drought preparedness plans and policies to reduce the impacts of drought. Unfortunately, progress in drought preparedness during the last decade has been slow because most nations lack the institutional capacity and human and financial resources necessary to develop comprehensive drought plans and policies. Recent commitments by governments and international organizations and new drought monitoring technologies and planning and mitigation methodologies are cause for optimism. The challenge is the implementation of these new technologies and methodologies. It is critical for governments that possess this experience to share it with others through regional and global networks. One way to accomplish this goal is to create a network of regional networks on drought preparedness to expedite the adoption of drought preparedness tools to lessen the hardships associated with severe and extended drought episodes. [source]

Unauthorised development and seismic hazard vulnerability: a study of squatters and engineers in Istanbul, Turkey

DISASTERS, Issue 3 2008
Rebekah A. Green
Many cities in developing nations have experienced an influx of poor migrants in search of work. This population influx has often been accommodated through land squatting, irregular construction and unauthorised housing. For the urban poor, this has resulted in immediate affordable housing; however, this housing frequently has long-term vulnerability to natural hazards. This article examines the ways in which squatters in Istanbul, Turkey, understand the seismic vulnerability of their unauthorised housing. Distrust of professional engineers and contractors has led Istanbul squatters to believe that self-built housing will not only be less costly but also safer than commercially built housing. The impact of residents' risk perceptions on their vulnerability to natural hazards is examined through a comparison of social attitudes regarding safe housing and the quality of unauthorised construction. This comparison highlights how squatters' risk perceptions necessitate innovative means of reducing vulnerability in unauthorised neighbourhoods of developing cities. [source]

,We All Knew that a Cyclone Was Coming': Disaster Preparedness and the Cyclone of 1999 in Orissa, India

DISASTERS, Issue 4 2004
Frank Thomalla
Imagine that a cyclone is coming, but that those living in the affected areas do nothing or too little to protect themselves. This is precisely what happened in the coastal state of Orissa, India. Individuals and communities living in regions where natural hazards are a part of daily life develop strategies to cope with and adapt to the impacts of extreme events. In October 1999, a cyclone killed 10,000 people according to government statistics, however, the unofficial death toll is much higher. This article examines why such a large loss of life occurred and looks at measures taken since then to initiate comprehensive disaster-preparedness programmes and to construct more cyclone shelters. The role of both governmental organisations and NGOs in this is critically analysed. The good news is that, based on an assessment of disaster preparedness during a small cyclone in November 2002, it can be seen that at community-level awareness was high and that many of the lessons learnt in 1999 were put into practice. Less positive, however, is the finding that at the state level collaboration continues to be problematic. [source]

Constructing Vulnerability: The Historical, Natural and Social Generation of Flooding in Metropolitan Manila

DISASTERS, Issue 3 2003
Greg Bankoff
Flooding is not a recent hazard in the Philippines but one that has occurred throughout the recorded history of the archipelago. On the one hand, it is related to a wider global ecological crisis to do with climatic change and rising sea levels but on the other hand, it is also the effect of more localised human activities. A whole range of socio-economic factors such as land use practices, living standards and policy responses are increasingly influencing the frequency of natural hazards such as floods and the corresponding occurrence of disasters. In particular, the reason why flooding has come to pose such a pervasive risk to the residents of metropolitan Manila has its basis in a complex mix of inter-relating factors that emphasise how the nature of vulnerability is constructed through the lack of mutuality between environment and human activity over time. This paper examines three aspects of this flooding: first, the importance of an historical approach in understanding how hazards are generated; second, the degree of interplay between environment and society in creating risk; and third, the manner in which vulnerability is a complex construction. [source]

An inverse cascade model for self-organized complexity and natural hazards

GEOPHYSICAL JOURNAL INTERNATIONAL, Issue 2 2005
Gleb Yakovlev
SUMMARY The concept of self-organized complexity evolved from the scaling behaviour of several cellular automata models, examples include the sandpile, slider-block and forest-fire models. Each of these systems has a large number of degrees of freedom and shows a power-law frequency-area distribution of avalanches with N,A,, and ,, 1. Actual landslides, earthquakes and forest fires exhibit a similar behaviour. This behaviour can be attributed to an inverse cascade of metastable regions. The metastable regions grow by coalescence which is self-similar and gives power-law scaling. Avalanches sample the distribution of smaller clusters and, at the same time, remove the largest clusters. In this paper we build on earlier work (Gabrielov et al.) and show that the coalescence of clusters in the inverse cascade is identical to the formation of fractal drainage networks. This is shown analytically and demonstrated using simulations of the forest-fire model. [source]

Spatial assessment of hydrologic alteration across the Pearl River Delta, China, and possible underlying causes

HYDROLOGICAL PROCESSES, Issue 11 2009
Qiang Zhang
Abstract The alterations of the water level across the Pearl River Delta (PRD) were investigated using a ,range of variability approach' (RVA) based on monthly water level datasets extracted from 17 gauging stations. A mapping method was used to illustrate the spatial patterns in the degrees of alteration of water levels. The results indicated that more stations showing moderate and high alterations in monthly mean maximum and minimum water levels when compared with monthly maximum and minimum water levels. River channels characterized by higher alterations of water levels were observed mainly in the regions north of 22° 30,N. Alterations of water levels across the PRD were a consequence of various influencing factors. However, changed hypsography due to extensive and intensive human activities, particularly the large-scale dredging and excavation of the river sand, may be taken as one of the major causes for the substantial hydrologic alteration. This study indicated that the river channels characterized by altered water levels are mostly those characterized by highly and moderately intensive sand dredging. The changed ratio of the streamflow between Makou and Sanshui stations, the major upstream flow control stations, also influenced the water level alterations of the Pearl River delta. The results of this study will be of great significance in water resources management and better human mitigation of the natural hazards due to the altered water level under the changing environment. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Rainfall-induced landslides and debris flows

HYDROLOGICAL PROCESSES, Issue 4 2008
Giovanni B. Crosta
Abstract In this preface we introduce the special issue on rainfall-induced landslides and debris flows. The topic is of high interest for many practical and scientific reasons. In fact, rainfall is the most relevant factor for the triggering of both shallow and deep-seated landslides, and rainfall analysis is the most frequently adopted approach for forecasting the occurrence of such phenomena. The six papers of the special issue cover most of the key issues relative to rainfall-induced landslides. Starting from the analysis of these contributions, we identify and discuss, in this paper, several main topics that deserve further research in the field of rainfall-induced landslide, such as the uncertainty of the data, the quality of geotechnical analysis, the validation of the models, and the applicability of results in the framework of natural hazards. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Hydrogeomorphology: overview of an emerging science

HYDROLOGICAL PROCESSES, Issue 4 2004
Roy C. Sidle
Abstract Here, we introduce a series of 14 papers generated from a symposium related to hydrogeomorphology that was part of the Fifth International Conference on Geomorphology. Additionally, recent developments in hydrogeomorphology are highlighted, particularly with respect to research in Japan. Linkages are drawn between natural hazards and the necessity to focus on hydrogeomorphic processes. Future research needs are discussed in the areas of temporal and spatial patterns of water and sediment dynamics, including the effects of distributed land management practices and interactions with natural hazards. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Experimental and numerical analysis of solitary waves generated by bed and boundary movements

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 8 2004
L. Cea
Abstract This paper is an experimental and numerical study about propagation and reflection of waves originated by natural hazards such as sea bottom movements, hill slope sliding and avalanches. One-dimensional flume experiments were conducted to study the characteristics of such waves. The results of the experimental study can be used by other researchers to verify their numerical models. A finite volume numerical model, which solves the shallow water equations, was also verified using our own experimental results. In order to deal with reflection on sloping surfaces and overtopping walls, a new condition for the treatment of the coastline is suggested. The numerical simulation of wave generation is also studied considering the bed movement. A boundary condition is proposed for this case. Those situations when the shallow water equations are valid to simulate this type of phenomena have been studied, as well as their limitations. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Post-flood field investigations in upland catchments after major flash floods: proposal of a methodology and illustrations

JOURNAL OF FLOOD RISK MANAGEMENT, Issue 4 2008
E. Gaume
Abstract Post-event survey and investigation is one way to gain experience on natural hazards. The importance of the systematisation and standardisation of such investigations and re-analysis is progressively recognised in all the geophysical sciences as shown by the growing number of scientific papers and programs on the subject. But how to proceed in the case of a flash floods, what type of data should be collected for what type of analyses and to explore which particular issues? To give a first answer to these questions, a methodology for post-flash flood field investigations has been developed under the EC FLOODsite project and tested under the EC HYDRATE project. This paper presents shortly the principles of this methodology and illustrates its application for the study of two major flash floods that occurred in November 1999 and September 2002 in the South of France. [source]

Widespread dispersal of Icelandic tephra: how does the Eyjafjöll eruption of 2010 compare to past Icelandic events?,

JOURNAL OF QUATERNARY SCIENCE, Issue 5 2010
Siwan M. Davies
Abstract The Eyjafjöll AD 2010 eruption is an extraordinary event in that it led to widespread and unprecedented disruption to air travel over Europe , a region generally considered to be free from the hazards associated with volcanic eruptions. Following the onset of the eruption, satellite imagery demonstrated the rapid transportation of ash by westerly winds over mainland Europe, eventually expanding to large swathes of the North Atlantic Ocean and the eastern seaboard of Canada. This small-to-intermediate size eruption and the dispersal pattern observed are not particularly unusual for Icelandic eruptions within a longer-term perspective. Indeed, the Eyjafjöll eruption is a relatively modest eruption in comparison to some of the 20 most voluminous eruptions that have deposited cryptotephra in sedimentary archives in mainland Europe, such as the mid Younger Dryas Vedde Ash and the mid Holocene Hekla 4 tephra. The 2010 eruption, however, highlights the critical role that weather patterns play in the distribution of a relatively small amount of ash and also highlights the spatially complex dispersal trajectories of tephra in the atmosphere. Whether or not the preservation of the Eyjafjöll 2010 tephra in European proxy archives will correspond to the extensive distributions mapped in the atmosphere remains to be seen. The Eyjafjöll 2010 event highlights our increased vulnerability to natural hazards rather than the unparalleled explosivity of the event. Copyright © 2010 John Wiley & Sons, Ltd. [source]

Hindcasting extreme events: the occurrence and expression of damaging floods and landslides in Southern Italy

LAND DEGRADATION AND DEVELOPMENT, Issue 4 2006
M. L. Clarke
Abstract Extreme rainstorm events across the Mediterranean have caused significant loss of life and damage to property and livelihoods. Italy is particularly vulnerable to natural hazards with recent events such as the 1996 floods in Versilia and the 1998 mass-movement failures at Sarno causing the deaths of 174 people. We have analysed 50 years of rainfall records to hindcast extreme rainstorms that have affected the eastern Basilicata region of southern Italy. Historical and archive data of individual floods and landslides have been compared with their antecedent rainfall conditions in order to characterize the nature of events that cause damage to society and infrastructure. Analysis of extreme-event frequency shows a decreasing annual trend related to changes in regional climate conditions in the western and central Mediterranean driven by changes in the strength of the North Atlantic Oscillation. Land-degradation problems associated with floods and landslides are decreasing due to a drier winter climate coupled with improved hazard mitigation. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Extreme versus quotidian: addressing temporal dichotomies in Philippine disaster management

PUBLIC ADMINISTRATION & DEVELOPMENT, Issue 3 2008
Francisco G. Delfin Jr.
Abstract Brief narratives of two recent events in Luzon island,a flashflood in Angeles City and an eruption of Mayon volcano,underscore the disparity between natural hazards as amplifiers of everyday hardship for many Filipinos and the Philippine disaster management system's orientation towards extreme-event response. Three major factors contribute to this dichotomy. First, population dynamics combined with the lack of access to resources compels poor Filipinos to live and work in hazardous areas, discounting risk from extreme natural events to focus on daily needs. Second, the institutional setting of the country's disaster management within the military establishment makes it difficult, though not impossible, to focus and address the underlying causes of vulnerability. Third, existing modes of funding disaster expenditures are all biased towards immediate response rather than long-term risk-reduction. The implications of these findings to disaster management and research in the Philippines are identified. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Safe place or ,catastrophic society'?

THE CANADIAN GEOGRAPHER/LE GEOGRAPHE CANADIEN, Issue 4 2000
Perspectives on hazards, disasters in Canada
The essay introduces public risk and destructive events in Canada, their conceptual and policy implications. The discussion is developed in four main steps. First, some widely held, if contradictory, perceptions of public security are identified. A relatively high level of personal safety for most Canadians is attributed to large government and private investments. But these have not prevented recurring disasters, nor singular vulnerability for certain groups and parts of the country. Meanwhile, some novel dangers of modern living compromise the safety of all Canadians. The second section examines evidence of losses from a broad range of hazards, and related, risk-averting investments. The national geography of dangers is shown to have been transformed and reorganized by post-World War II developments. Losses, even from natural hazards, are identified with common, nationwide behaviours and infrastructure, especially motorised mobility and consumer products. A fourth section looks at some appropriate conceptual frameworks. Charles Perrow's idea of ,organizational society' is considered, and Ulrich Beck's of ,risk society', including his view that late modern societies shift towards a ,catastrophic' condition. In general, the Canadian scene and these ideas support a human ecological view of modernity, but challenge an agent-specific and extreme event approach that had prevailed in hazards geography. ,Manufactured' vulnerability is a neglected but decisive element. The social space of risks is shown to be recast around changing priorities for, and social justice in, public security and emerging crises of personal safety. Risk aversion turns upon questions of the acceptability of risks, acceptance for and by whom, and how it is achieved. For academic work, this suggests a reexamination of risk knowledge and its ,social construction'. La dissertation aborde le sujet des évènements destructifs et du risque public au Canada, leurs implications conceptuels et de principe. La discussion est développée en quatre étapes principales. Premièrement, certaines perceptions de la sécurité publique tenues par beaucoup, non sans être contradictoires, sont identifiées. Un niveau relativement élevé de sécurité personnelle pour la plupart des canadiens est attribuéà un gouvernement de grande taille et aux investissements privés mais ceux-ci n'ont pas empêché des désastres de se reproduire, ni une vulnérabilité singulière pour certains groupes et certains endroits du pays. Entretemps, de nouveaux dangers de la vie moderne compromettent la sécurité de tous les canadiens. La deuxième section examine la preuve d'une perte à partir d'une gamme étendue de risques et d'investissement risqués et apparentés. II est montré que la géographie nationale des dangers a été transformée et réorganisée par des développements de l'après seconde guerre mondiale. Les pertes, même provenant de risques naturels, sont identifiées avec des comportements et infrastructures en commun et dans tout le pays, spécialement la mobilité motorisée et les produits de consommation. Une quatrième section examine les supports de travail conceptuels appropriés. L'idée de Charles Perrow d'une ,société structurelle' est prise en considération, et celle d'Ulrich Beck d'une ,sociétéà risque' comprenant sa vue que les dernières sociétés modernes s'accélèrent vers une condition ,catastrophique'. En général, le monde canadien et ces idées soutiennent une vue humaine et écologique de la modernité, mais défie un agent spécifique et une approche extrême des évènements qui avait prévalu dans la géographie des risques. La vulnérabilité,fabriquée' est un élément négligé mais décisif. II est démontré que le rôle de l'espace de risques social est redistribué selon des priorités qui changent pour, et la justice sociale dans, la sécurité publique et les crises qui émergent dans la sécurité personnelle. L'aversion des risques révolve autour des questions d'acceptabilité des risques, risques acceptés pour et par qui, et la façon dont cela est accompli. En ce qui concerne un travail théorique, cela suggère une réexamination de la connaissance des risques et de sa ,construction sociale'. [source]