Le permafrost de montagne est menacé par le réchauffement atmosphérique, une évolution qui s’accompagne de l’augmentation des phénomènes tels que les chutes de pierres, la formation de thermokarsts et l’accélération des glaciers rocheux. La déstabilisation des glaciers rocheux, qui compromet l’intégrité structurelle de ces formes, semble liée au réchauffement atmosphérique, et a suscité un intérêt grandissant au cours des dernières années. Ce phénomène, qui peut être provoqué par le réchauffement du pergélisol ou des contraintes mécaniques externes, est caractérisé par une accélération anormale des glaciers rocheux affectés, et par l’apparition des signes géomorphologiques telles que des fissures et des crevasses à sa surface. Bien que ce processus peut être transitoire, il peut déterminer une phase de crise amenant le glacier rocheux à un effondrement.Cet étude se préfixe de fournir une première évaluation des phénomènes de déstabilisation de glacier rocheux à l’échelle des Alpes françaises. Dans un premier temps, l’empreinte spatiale du pergélisol a été évaluée afin de produire une carte de répartition du pergélisol régionale, un outil nécessaire pour estimer l’état du permafrost dans les glaciers rocheux. La deuxième étape a consisté à identifier les formes déstabilisées grâce à une observation ponctuelle des images aériennes afin d’identifier les caractéristiques typiquement observables sur les glaciers rocheux déstabilisés. Il est alors possible de comprendre les conditions topoclimatiques typiques dans lesquelles se produit ce phénomène et de repérer les formes susceptibles de subir ce processus. Enfin, les efforts ont été concentrés sur le glacier rocheux du Lou, déstabilisé, qui, du fait d’un détachement de couche active, a conduit à une lave torrentielle en Août 2015. L’analyse a visé à mieux définir les circonstances de cet événement, en mettant l’accent sur les facteurs de préconditionnement, de préparation et de déclenchement et sur leur interaction avec le processus de déstabilisation.Les résultats ont fourni des informations riches sur la zone périglaciaire de la région. La modélisation de la répartition du pergélisol a mis en évidence les étendues de la zone périglaciaire dans la région qu’on peut trouver sur les pentes de débris au-dessus de 2300 - 2500 m.a.s.l. en fonction de l’exposition solaire et des caractéristiques régionales des précipitations. L’observation des photographies aériennes a permis d’observer 46 formes en cours de déstabilisation, soit 12% des glaciers rocheux actifs des Alpes françaises. Il apparaît que la déstabilisation est plus susceptible de se produire dans certaines conditions topoclimatiques locales spécifiques, en particulier dans des pentes exposées au nord, raides et convexes situées aux marges inférieures de la zone de pergélisol. Un grand nombre de glaciers rocheux ne présentant actuellement aucune déstabilisation sont donc susceptibles d’être affectés par une déstabilisation future. L’analyse du glacier rocheux du Lou a révélé que la déstabilisation est liée à une avancée rapide du front vers un ravin torrentiel. Ce processus semble avoir accru la prédisposition des matériaux détritiques du front à être mobilisés par du ruissellement, des précipitations relativement modérées ayant suffi à déclencher l’événement.Malgré les incertitudes liées aux méthodes impliquées, les résultats suggèrent que les conditions favorables à la déstabilisation sont fréquentes, et que cette dernière peut augmenter le niveau de risque si le site est connecté à des infrastructures humaines. Des efforts supplémentaires doivent donc être entrepris, afin d’améliorer la compréhension de ces processus, notamment par la surveillance des sites ainsi que par une évaluation locale complète des cascades de processus liés à ce phénomène. / As occurring to several geosystems on our planet, mountain permafrost is threatened by climate change as prolonged warming may compromise the geotechnical properties of the frozen ground. As result, increasing occurrence of rockfall activity, thermokarst formation and rock glacier acceleration was observed in the past decades. Rock glacier destabilization, a process that compromises the structural integrity of these landforms, seems to be linked to atmospheric warming, gaining interest in the past years. The destabilization, which may be triggered by warming permafrost or mechanical stress, is characterized by an anomalous acceleration of the landform and the occurrence of specific features such as cracks and crevasses on its surface. Although the occurrence of these processes is mostly transitory, determining a textit{crisis} phase of the landform, in exceptional cases it may lead the rock glacier to structural collapse.This PhD thesis provided an assessment on the occurrence and related processes of rock glacier destabilization in the French Alps. At first, the spatial occurrence of debris permafrost was assessed in order to provide the permafrost distribution map of the French Alps, a tool that was necessary to evaluate permafrost conditions at rock glaciers sites. The second step consisted in an identification of destabilized rock glaciers in the region, which was done by multiple orthoimages interpretation aimed to identify features typically observable on destabilized rock glacier. Once identified the destabilized rock glaciers it was possible to analyse the typical topographical settings in which destabilization occurs and to to spot those landforms that are susceptible to experience this phenomenon. After these efforts at the regional scale, the focus was shifted towards local scale investigations at the Lou rock glacier, a partially destabilized landform that, due to frontal failure, in August 2015 triggered a debris flow that caused significant damages to buildings. The analysis aimed to better define the circumstances of this event, focusing on preconditioning, preparatory and triggering factors and their interaction with the destabilization process.The results provided interesting insights on the issue of destabilizing rock glaciers in the region. Permafrost distribution modeling demonstrated the large extents of the periglacial zone in the region as it can be found in debris slopes above 2300 - 2900 m.a.s.l. depending upon solar exposure and regional precipitation characteristics. Rock glacier destabilization was observed on 46 landforms, i.e. the 12% of the active rock glaciers. Destabilization was found to be more likely to occur in specific local topo-climatic conditions, consisting of north facing, steep and convex slopes at the lower margins of the permafrost zone. A large number of rock glaciers currently not showing destabilization was found to be located in these conditions and suggested to be susceptible to future destabilization. As demonstrated by the Lou rock glacier analysis, destabilization was found to be a relevant phenomena in the context of permafrost hazards. At this site, rock glacier destabilization was linked to a rapid frontal advance towards a torrential gully. This process seemed to have increased the site predisposition to frontal failure as a mild rainstorm was sufficient to trigger the event.Despite methodological uncertainties, results indicated that destabilization occurrence is widespread and it may rise the hazard level of a site connected to human infrastructures. Therefore, it is suggested that, where it has been modelled and where stakes may be at risk downslope, rock glacier destabilization deserves to be more carefully investigated. In this sense further efforts should focus towards a better understanding of the destabilization process by site monitoring as well as towards a comprehensive hazard assessment linked to this phenomenon.

No description available.

Natural hazards have been an increasing problem in wildland recreation areas. This study attempted to identify factors affecting park visitor perception of and preparedness for hazards. A model was formulated incorporating three major independent variables which might affect park visitor responses to hazards. These were: (1) previous experience, (2) information about hazards provided by the park administration (such as warnings located on signs or in brochures), and (3) visitor perception of whether responsibility for hazards rests with the individual or with an outside authority such as government or God. Trip length and knowledge of hazards were also thought to be factors influencing visitor behavior. The model was tested during the summer of 1976 in four study areas: Arches National Park, Canyonlands National Park, Glen Canyon National Recreation Area, and the High Uintas Primitive Area. Personal interviews and questionnaires were used to obtain the data. The results showed that the set of influences upon visitor behavior varied with each park studied. In general, however, hazard warnings and visitor perceptions of where responsibility for hazards lay had no influence upon visitor behavior. In contrast, previous experience, trip length, and visitor knowledge about hazards had important influences upon visitor preparations for hazards.

Determining where people are most likely to suffer losses and have difficulty in evacuating from a hurricane is important to developing a hurricane response strategy. This thesis proposes a methodology for modeling and assessing evacuation vulnerability to a specific hurricane and applies this method to study Pinellas County, Florida. The vulnerability of Pinellas County to evacuation problems and the degree of loss that may be suffered from a hurricane is quantified in the Hurricane Evacuation Vulnerability Index. This index is the sum of three indices that represent social, transportation, and geophysical aspects of hazards research. Social vulnerability is assessed with an existing social vulnerability model that uses census data to locate areas where people will have difficulty evacuating based on demographic variables. Areas where people are vulnerable to traffic problems due to the condition of the evacuation routes are identified with a model developed using GIS. The degree of damage these areas may suffer from a specific hurricane is modeled using a tightly coupled GIS program, HAZUS-MH. These loss estimates are used to identify areas where evacuation may be necessary. The Hurricane Evacuation Vulnerability Index is mapped to show the areas that are most vulnerable to evacuation problems and may suffer losses to the built environment and subsequent human displacement. The Hurricane Evacuation Vulnerability Index is a valuable tool for emergency planning. The results are useful in allocating and directing resources to facilitate the evacuation of vulnerable areas. Emergency management officials can prepare evacuation plans based on the modeled results. Traffic management strategies can be implemented to reduce traffic congestion along evacuation routes. Transportation resources, such as buses, can be directed to areas where people do not have the resources to evacuate.

In response to the rising costs of floods, the United States has adopted sophisticated programs to mitigate the loss of life and property. However, the efficient implementation of certain aspects of flood policy has taken precedence over effective communication. The scope of the National Flood Insurance Program and the efficient coding of "the 100 year flood" have led to a pervasive use of the term in both formal and informal risk communication. When officials began consciously communicating flood policy to the public, they assumed a narrow "engineering" model and did not fully anticipate the influence of informal communication on the perception of flood risk. The effectiveness of the "100 year flood" as a means to change attitudes or motivate behaviors was not assessed. Nor was its utility in increasing public understanding of flood risk. New explanatory methods have been introduced, but they, too, have yet to be tested. This project evaluated the effectiveness of four methods commonly used to communicate the risk associated with policy's benchmark flood. These include: a 100 year flood; a flood with a 1 percent chance of occurring in any year; a flood with a 26 percent chance of occurring in 30 years; and a flood risk map available through Project Impact. Data were collected using a structured face to face questionnaire survey of residents living in Wimberley, Texas. Respondents included individuals who lived inside the boundaries of official flood plains, as well as those who did not. Comparable questions regarding uncertainty, perceived need for protection, and levels of concern were asked using each of the four methods of description. Qualitative observations were made during both the interviews and the collection of secondary data. Results showed a significant disjuncture of understanding and persuasion with each method; potentially serious problems with the 26 percent chance method; and a preference for concrete references in describing risk. It is recommended that use of the 26 percent chance method be discontinued. Both the 100 year flood and the map performed better than expected; these descriptions are recommended with reservations in lieu of more contextually appropriate methods of communication and policy formation.

The Indian Ocean tsunami on 26 December 2004 made many New Zealanders more aware of the devastating affects that a tsunami can have on coastal communities, and highlighted the need for people living in the coastal zone to be prepared for natural hazard events. The east coast of New Zealand is at high risk from both local and distantly generated tsunami, and Poverty Bay and Hawke Bay have been identified among the most at risk areas from tsunamis in the country. Three surveys were conducted between January and November 2006 to assess community understanding of, and preparedness for tsunami risk in the eastern North Island, New Zealand. These surveys were a camping ground visitor survey; a tourism sector preparedness survey; and the 2006 National Coastal Survey. Findings of all three surveys show that the general public does not appear to have sufficient knowledge of tsunami risk in their area. Also, there does not appear to be adequate information on tsunamis available to the public. Understanding of official tsunami warnings was high amongst residents surveyed in the 2006 National Coastal Survey. However, it was low amongst visitors surveyed in the camping grounds, with the majority of camping ground survey respondents indicating that they do not know what makes up the New Zealand public notification system. It is encouraging to find that overall the public are aware of the correct actions to take in the event of a tsunami warning being issued. Staff in hotels/motels in the Napier area were not well prepared for managing natural hazard events, with the majority of respondents having no training for dealing with emergencies, and none of those who had received training had received training for tsunami hazards. It is recommended that steps be taken to better educate and prepare the public and tourism managers in eastern North Island communities. This will require not only public education but a range of activities that engage, empower and motivate at-risk communities to respond effectively and appropriately to tsunami warnings.

Reinsurance is one of the most important tools to be used by insurance companies, for managing risks. This is an effective way / however, there are situations where reinsurance is insufficient, such as the occurrence of a natural hazard. When a natural hazard occurs, many insured experience loss at the same time, which drains the reinsurance market capacity. If future market capacity could be forecasted, then it would be easier for companies to decide when to include cat bonds or any other additional securities in their portfolio. In order to establish a model for market capacity, its relationship with other market parameters and the association among parameters are examined. In this study, these relationships are analyzed and used to establish an algorithm for predicting the next years reinsurance capacity. Moreover, last 10-year data for market capacity is used to establish and AR(1) model, in order to create a comparison with the algorithm. A case study of cat bonds is done, which uses the pricing load calculation of the Lane model and aims to ease the decision-making process by comparing the loads of cat bond and reinsurance pricing.

Anecdotal evidence in disaster studies suggests that multifamily housing takes longer to recover than single family homes, but almost no studies have provided quantitative evidence to clarify this “multifamily home lag” phenomenon. This research examines the recovery of single family, duplex, and apartment complex housing in south Miami-Dade County, Florida, after 1992 Hurricane Andrew to determine if there is indeed a "multifamily home lag." This research also provides a better understanding of the factors influencing the recovery trajectories of these three housing types. The findings of this research indicate that duplexes and apartment buildings have slower recovery trajectories than single family dwellings. In addition, rental housing, housing that sustained higher levels of damage, and single family dwellings and duplexes located in predominately non-Hispanic Black neighborhoods show significantly slower recovery trajectories. The analyses specific to apartment buildings also finds that apartment buildings with fewer than 10 units have significantly slower recovery trend than apartment buildings with more than 50 units.

This research investigates the public perception of hurricane forecasting and warning systems with a view to improving response activities. The hazard literature shows that the effectiveness of such systems is contingent upon on the smooth operation of all components of the system and that warning recipients fully understand the implications of the warning message by taking appropriate action. It is argued that public perception of warning systems will vary depending on various socio-demographic factors, such as age, gender, level of education, socioeconomic status and area, factors that will ultimately influence overall effectiveness. To test this, a questionnaire survey was undertaken of local residents in Lake Wales, Florida, a town that was severely impacted by three hurricanes in the 2004 season. Results indicate that some demographic factors appear to influence an individual's willingness and ability to respond. Overall, level of education and income seem to have a larger affect on response than age or gender. The two sampling areas in Lake Wales elicited more significant differences than do the other variables but, the area variable takes into account all of the other factors of age, gender, level of education, and socioeconomic status. In fact, what is argued here is that area actually acts as a surrogate variable for the others. Therefore, it is not where one is located that makes a difference but the composition of the people in the location itself.

<p><font face="Cambria" size="3"><font face="Cambria" size="3"><font face="Cambria" size="3"><font face="Cambria" size="3"><font face="Cambria" size="3"><font face="Cambria" size="3"> <p>The objective of the study was to find out whether the decentralisation of responsibulities for social economics development facilitated the management of disaster risk during the 2007 floods in Mozambique. the specific aims of the study were to : analyse <font face="Cambria" size="3"><font face="Cambria" size="3">and discuss national policies for decentralisation and their significance for DRM.&nbsp / Investigate which responsibilities, human and financial resources were available to local governments&nbsp / for the planning, implemantations and monitoring of DRM activities. Identify&nbsp / mechanisms institutions and activities for DRM and&nbsp / find out whether they provided to be effective. Explore how concerned&nbsp / communities participated in DRM activitiesto reduce&nbsp / their vulnerability to disaster risk.&nbsp / &nbsp / &nbsp / &nbsp / &nbsp / &nbsp / &nbsp / &nbsp / </font></font><font face="SymbolMT" size="3"><font face="SymbolMT" size="3"> <p>&nbsp / </p> </font></font>&nbsp / </p> <p>&nbsp / </p> <p>&nbsp / </p> <p>&nbsp / </p> <p>&nbsp / </p> </font></font></font></font></font></font></p> <p>&nbsp / </p>