Back analysis of the institutional and social responses to the eruption and the lahars of Mount Pinatubo Volcano from 1991 to 1998 (Central Luzon, Philippines)

International audienceMount Pinatubo volcano erupted in June 1991 in the main island of Luzon belonging to the Philippines archipelago. Huge economic losses and population exodus have followed. This major crisis has been relayed with other crises due to rainfed lahars which have been supplied with eruption deposits. These lahars have occurred every year since 1991 during the rainy season. They will probably last until 2005. After a brief presentation of the Philippine official response system to disasters, this paper draws up a critical analysis of the different kinds of institutional and social responses deployed to manage the different crisis and post-crisis phases of this event. Based on three viewpoints: from population, media and other actors, this analysis attempts to point out the strengths and weaknesses of the official management system, especially by studying the efficiency and the range of the solutions taken. So, it appears that the management of the June 1991 main crisis (eruption) was a success. On the other hand, difficulties have occurred with lahars risk management. Indeed, these lahars have obliged the authorities to protect and relocate thousands of people. In spite of persistent problems, the management system (monitoring/warning/evacuation) of lahar crises improves year after year. Failures appear especially within the rehabilitation program (protection/rehousing). Many direct (lack of means, preparedness, coordination, dialog,etc.) and indirect (politico-administrative, socio-economic, cultural contexts) factors come together to lock the wheels ofthe institutional response system. They defer the socio-economic start of this vital northern Philippines area

Cartographie de la vulnérabilité des populations face aux phénomènes volcaniques et aux lahars du Mont Pinatubo (Philippines) : cas du bassin de la rivière Pasig-Potrero (province de Pampanga)

International audienceThis study aims at assessing the vulnerability of populations in the Pasig-Potrero River basin, who are threatened by the recurrent lahars of Mt Pinatubo volcano (Philippines) in the aftermath of its 1991 eruption. A survey, carried out between February and March 1998, enabled us to define and to map different levels of risk perception, the quality of potential behavioural patterns in the event of further lahars, and attitudes in the event of an evacuation order. It was then possible to work out a classification and to map the patterns of human vulnerability in the study area. This study points out that, while risk perception is quite high, some problems remain, notably concerning the warning systems and the behaviour of the population in the case of an evacuation. Theses results should assist in elaborating risk and disaster scenarios. They are intended to be used for operational purposes in crisis management such as the organization of disaster relief, and in land use planning

Using the 13C/12C Ratio of Bacteria-Specific Fatty Acids to Determine the Lability of Terrestrial and Marine Organic Matter in Coastal Sediments

The bottom waters of the St. Lawrence Estuary and Gulf are currently characterized by low dissolved oxygen levels (hypoxia), which influence the health of this ecosystem. The progression of hypoxia since the beginning of the century is due in part to an increase in the flux of organic matter (OM) and inorganic nutrients discharged in this aquatic system by the St. Lawrence River. The increase in nutrient abundance leads to higher primary productivity and concentrations of dissolved and particulate OM in the water column, which in turn results in a higher consumption rate of oxygen during the degradation of OM by microorganisms. To further our understanding of the carbon cycle in the St. Lawrence system, the biological lability of terrestrially-derived and marine OM was indirectly estimated through the analysis of the 13C/12C ratio of bacteria-specific fatty acid (iso C15:0 and anteiso C15:0) using gas chromatography coupled to an isotope ratio mass-spectrometer (GC-IRMS). Ubiquitous bacteria strains responsible for the degradation of OM were cultivated in marine broth enriched in 13C with 13C-sodium acetate to assess the relationship and isotopic fractionation between the 13C signature of the food source and that of the bacteria. Using this calibration and the isotopic signature of the terrestrial and marine OM end-members, it was possible to determine the proportions of each type of OM being degraded at the different sampling stations along the St. Lawrence Estuary and Gulf continuum. Better constraining of the role of bacteria in terrestrial and marine OM degradation within the St. Lawrence Estuary and Gulf allows for better understanding of the causes driving deep water hypoxia and, eventually, will allow better remediation efforts to improve the health of this important ecosystem. Finally, as part of a small side project, the method used to decarbonate samples with HCl vapour in preparation for elemental analysis (EA) was investigated using a 13C-labelled short-chain organic acid to assess the extent to which the acid is lost through volatilization upon its protonation

“Hurricaned” territories. Hurricane hazards and their impacts

This issue of EchoGéo investigates the environmental, social, economic and political consequences of hurricanes on territories and their management. The French neologism “cycloné” (or “hurricaned”) appeared on social networks in 2017 after hurricane Irma hit the West Indies. The word refers to the destruction caused by category 4 or 5 hurricanes, but also to their victims’ challenging experiences. These events raise the question of the ex-ante and ex-post evaluation of damages in terms of man..

Territoires « cyclonés ». Les aléas cycloniques et leurs impacts

Ce dossier d’EchoGéo est centré sur les conséquences environnementales, sociales, économiques et politiques des cyclones sur les territoires, et leur gestion. Le néologisme « cycloné » est apparu sur les réseaux sociaux en 2017 après le passage du cyclone Irma aux Antilles. Il renvoie à tout type de destruction causée par des cyclones de catégorie 4 ou 5, mais aussi à l’expérience humaine éprouvante vécue par les sinistrés. Ces événements posent question en termes d’évaluation ex ante et ex p..

Cartographie de la vulnérabilité aux phénomènes volcaniques et aux lahars du Pinatubo(Philippines). Cas du bassin de la rivière Pasig-Potrero (Province de Pampanga)

International audienceThis study aims at assessing the population vulnerability in the Pasig-Potrero River basin threatened by the recurrent lahars of Mt Pinatubo volcano (Philippines) subsequent to its 1991 eruption. A survey carried out between February and March 1998 enabled us to define and to map different levels of risk perception, the quality of the potential behaviors in the event of further lahars and of the demeanors in case of evacuation order. It was then possible to work out a typology and a cartography of human vulnerability in this study area.This study points out that, even though the risk perception is quite high, some problems remain, notably concerning warning and behaviors in case of evacuation.This work is part of a larger framework including population vulnerability assessment around Mt Pinatubo (social and institutional vulnerability). It also aims at estimating the effects, notably the territorial consequences, occurred as a result of a crisis linked to the volcano and its lahars, and that has been lasting for eight years. These results should allow to elaborate some risk and disaster scenarios. They are intended to be used as operational purposes in crises management such as relief arrangement, land use planning.Cette étude a pour objectif d'évaluer la vulnérabilité des populations du bassin de la rivière Pasig-Potrero menacé par les lahars récurrents du volcan Pinatubo (Philippines) suite à l'éruption de 1991. A partir d'une campagne d'enquêtes sur le terrain, réalisée entre février et mars 1998, on a pu définir et cartographier différents niveaux de perception du risque, la qualité des comportements potentiels face aux lahars ainsi que des attitudes en cas d'ordre d'évacuation. Ces données ont ensuite permis de réaliser une typologie et une cartographie de la vulnérabilité dans le secteur d'étude.Il en ressort que si la perception du risque est assez élevée, des problèmes subsistent, notamment en matière d'alerte et de comportements en cas d'évacuation. La qualité de l'alerte a aussi montré, dans le passé, des carences qu'il convient aujourd'hui de combler.Ce travail s’inscrit dans un cadre plus large d'évaluation de la vulnérabilité des populations face au volcan Pinatubo (vulnérabilité sociale, institutionnelle...) el des conséquences, notamment territoriales, de huit années de crises liées à l'éruption, puis aux lahars.Ces conclusions peuvent guider l'élaboration de scénarios de risque et de catastrophe, utiles à des fins opérationnelles (planification des secours, aide à la gestion des crises, aménagement du territoire...)

Conformational disorder in phosphopeptides: solution studies by CD and NMR techniques

In the last few years intrinsically disordered proteins (IDPs) have received great attention from the scientific community as they participate in several important biological processes and diseases. The intrinsic disorder and flexibility of IDPs grant them a number of advantages with respect to ordered proteins, such as conformational plasticity to bind several targets, a large interaction surface, involvement in high specificity/low affinity interactions, enhanced binding kinetics. It is assumed that post-translational modifications such as phosphorylation can stimulate structural rearrangement in IDPs and facilitate their binding to partners. To better understand at a structural level the multifaceted mechanisms that govern molecular recognition processes involving IDPs, we designed, synthesized by solid phase methods, and structurally characterized unstructured peptides. These molecules contain a putative disordered module, flanked at either the N- or C-terminal ends by a different phosphorylated amino acid (serine or threonine) to mimick the effects of phosphorylation. The absence of an ordered state in the designed peptides was proved experimentally by CD and NMR conformational studies that were carried out under different solution conditions

Changements côtiers et inondations suite au passage d’un ouragan extrême (Irma, 2017) aux Petites Antilles

Cette étude porte sur les changements côtiers et les inondations suite au passage d’un ouragan de catégorie 5 (Irma) les 5 et 6 septembre 2017 sur les îles de Saint-Martin et Saint-Barthélemy aux Antilles. Deux missions de terrain à t+2 mois et t+8 mois sur les deux îles ont permis d’analyser les impacts de l’ouragan Irma sur des côtes basses particulièrement sensibles aux événements météo-marins extrêmes et aux pressions anthropiques. Le retour d’expérience a été réalisé sur les côtes les plus touchées par l’évènement. Pour comparer les impacts de l’ouragan Irma et les interactions avec les systèmes côtiers et les infrastructures côtières, nous avons choisi d’analyser des côtes peu urbanisées et des littoraux densément aménagés. La méthode a reposé sur l’analyse d’images satellites avant le passage de l’ouragan Irma et l’analyse d’images drones post-évènement. Elle s’est aussi appuyée sur des observations géomorphologiques, la mesure des hauteurs de vagues et la cartographie des espaces inondées. Les systèmes côtiers ont répondu très différemment en fonction du degré d’artificialisation de la côte, révélant des changements côtiers variés, des transferts sédimentaires perturbés et une influence sur les hauteurs d’eau maximales à la côte.This study deals with the coastal changes, flooding and damage after the passage of a category 5 hurricane (Irma) on 6 September 2017 over the islands of Saint-Martin and Saint-Barthélemy in the Lesser Antilles. Two field work were made 2 and 8 months after the catastrophe over the two islands. It made it possible to analyze the impacts of Hurricane Irma on the low-lying shores that are particularly susceptible to extreme cyclonic events and anthropogenic stressors. The field work was made on the coasts most affected by the cyclonic event. To compare impacts of hurricane Irma and interactions with coastal systems and coastal infrastructure, we chose to analyze undeveloped to highly urbanized coasts. The method was based on the analysis of satellite images and Unmanned Aerial Vehicle surveys. It also relied on qualitative observations, geomorphological and sedimentary surveys and the measurement of wave run up and the mapping of flooded areas. The coastal system revealed a variety of morpho-sedimentary responses on both the natural and highly urbanized coasts, showing varied coastal changes, perturbed sedimentary transfers and the effects of coastal structures and street on flow channeling and on water level increas

La protection du bâti individuel et des commerces contre l’inondation. Opportunités et obstacles

L’article propose un bilan des opportunités et des obstacles soulevés par l’adaptation des bâtiments au risque inondation. Cette question est devenue centrale dans les programmes de réduction du risque inondation. A partir d’une étude bibliographique et en s’appuyant sur une enquête approfondie sur la ville de Quimper, les auteurs mettent en relief la diversité des situations locales et la difficulté à aborder la réduction de la vulnérabilité des bâtiments par des mesures coercitives et générales. 290 habitations et 194 commerces ont été diagnostiqués sur la commune de Quimper afin de déterminer leur degré de vulnérabilité face à une inondation. Les occupants ont été questionnés sur leur degré de connaissance du risque et leur consentement à mettre en œuvre des mesures de protection de leur bâtiment. Sur ce dernier point, l’enquête montre que la mauvaise connaissance du risque n’est pas le seul facteur de désintérêt des habitants face à ce type de mesures. L’engagement des personnes est fortement lié à l’attachement au bien et aux facteurs qui en découlent (statut propriétaire/locataire, âge…). Les commerçants représentent une population difficile à mobiliser compte tenu du faible taux de propriétaires occupants et du renouvellement rapide des gérants

DAÑOS CATASTRÓFICOS EN CARRETERAS INSULARES [Material gráfico]

Copia digital. Madrid : Ministerio de Educación, Cultura y Deporte, 201