721 research outputs found
Chapter 16 Volcanic hazard vulnerability on SĂŁo Miguel Island, Azores
AbstractIn recent years much progress has been made in researching a wide variety of extreme events on SĂŁo Miguel. In addition there are a number of volcano-related risks that impact upon the people of SĂŁo Miguel. Some of these may occur both before and during volcanic emergencies (e.g. earthquakes), whilst others render SĂŁo Miguel dangerous even when its volcanoes are not erupting (e.g. flooding, landslides, tsunamis and health impacts, especially the effects of CO2seepage into dwellings). In this chapter we first define what vulnerability means to the people of SĂŁo Miguel, and relate this to the cultural and economic characteristics of the island. The following aspects of vulnerability are discussed: (a) physical (i.e. housing, settlement and the characteristics of evacuation routes and plans); (b) demographic and economic; and (c) social and cultural and perceptual (i.e. whether people have an accurate cognition of risk). Particular areas of concern relate to housing: the identification of isolated dwellings that would be difficult to evacuate; the vulnerability/resilience of evacuation routes following recent infrastructure improvements; characteristics of the island's transient population; management of livestock under emergency conditions; local leadership roles; and educational outreach.</jats:p
Macroalgal turfs in the Azores
Copyright © 2009 Blackwell Verlag GmbH.Studies on macroalgal communities of the Azores report algal turfs as one of the most conspicuous ecological entities occurring on the rocky shores of these islands. The present study investigates the influence of shore height and substratum on turf composition. Data were analysed using the software PRIMER and results confirmed the previous distinction between calcareous, dominated by articulated coralline algae, and non-calcareous turfs, characterized mainly by small red algae. However, no differences in species composition were found in either type of turf occurring on different substrata or at different shore levels
Non-eruptive geological hazards of dormant volcanoes: Sao Miguel, Azores Perigos geologicos nao erurptivos en vulcoes adormecidos: Sao Miguel, Acores
SĂŁo Miguel Island presents a diversity of geological
hazards that are related to non-eruptive processes. Frequent seismic swarms and destructive earthquakes, of volcanic and tectonically related origin, have been recorded on the Island since it was settled in the 15th century. Large areas of volcanic edifices of Sete Cidades, Fogo and Furnas are unstable. Steep slopes, unconsolidated and poorly consolidated materials, such as volcaniclastic deposits occasionally weathered by hydrothermal activity, play an important role in landslide activity. Slope instability is mainly triggered by intense rainfall, but also by seismic activity, sea and fluvial erosion and/or anthropogenic activity. Volcano degassing represents a major
risk during anomalous gas release and a continuous menace for the public health
Pulsed Doppler-free two-photon spectroscopy of polyatomic molecules
Doppler-free two-photon electronic spectra of a large polyatomic molecule are recorded for the first time with pulsed laser radiation of near Fourier-transform limited bandwidth (Îvnot, vert, similar100 MHz). The resolution obtained is sufficient to resolve individual rotational lines. Due to the high density of these rotational transitions a strong Doppler-broadened background is observed, which is, however, subtantially reduced by suitable choice of photon polarizations. Different vibronic bands of benzene (C6H6) are investigated and very accurate rotational constants are found
The algal flora of the Azores: a historical and biogeographical approach.
43rd European Marine Biology Symposium. Ponta Delgada, Açores, 8-12 de Setembro de 2008
Azorean Coastal Communities. An On-going Study.
43rd European Marine Biology Symposium. Ponta Delgada, Açores, 8-12 de Setembro de 2008
Gaming with eutrophication: Contribution to integrating water quantity and quality management at catchment level
The Metropolitan Region of Sao Paulo (MRSP) hosts 18 million inhabitants. A complex system of 23 interconnected reservoirs was built to ensure its water supply. Half of the potable water produced for MRSP's population (35 m3/s) is imported from a neighbour catchment, the other half is produced within the Alto TietĂȘ catchment, where 99% of the population lives. Perimeters of land use restriction were defined to contain uncontrolled urbanization, as domestic effluents were causing increasing eutrophication of some of these reservoirs. In the 90's catchment committees and sub committees were created to promote discussion between stakeholders and develop catchment plans. The committees are very well structured "on paper". However, they are not very well organised and face a lack of experience. The objective of this work was to design tools that would strengthen their discussion capacities. The specific objective of the AguAloca process was to integrate the quality issue and its relation to catchment management as a whole in these discussions. The work was developed in the Alto TietĂȘ Cabeceiras sub-catchment, one of the 5 sub catchments of the Alto-TietĂȘ. It contains 5 interconnected dams, and presents competitive uses such as water supply, industry, effluent dilution and irrigated agriculture. A RPG was designed following a companion modelling approach (Etienne et al., 2003). It contains a friendly game-board, a set of individual and collective rules and a computerized biophysical model. The biophysical model is used to simulate water allocation and quality processes at catchment level. It articulates 3 modules. A simplified nutrient discharge model permits the estimation of land use nutrient exportation. An arc-node model simulates water flows and associated nutrient charges from one point of the hydrographical network to another. The Vollenweider model is used for simulating specific reservoir dynamics. The RPG allows players to make individual and collective decisions related to water allocation and the management of its quality. Impacts of these decisions are then simulated using the biophysical model. Specific indicators of the game are then updated and may influence player's behaviour (actions) in following rounds. To introduce discussions on the management of water quality at a catchment level, an issue that is rarely explicitly dealt with, four game sessions were implemented involving representatives of basin committees and water and sanitation engineers. During the game session, the participants took advantage of the water quality output of the biophysical model to test management alternatives such as rural sewage collection or effluent dilution. The biophysical model accelerated calculations of flows and eutrophication rates that were then returned to the game board with explicit indicators of quantity and quality. Players could easily test decisions impacting on qualitative water processes and visualize the simulation results directly on the game board that was representing a friendly, virtual and simplified catchment. The Agualoca game proved its ability to turn complex water processes understandable for a non totally initiated public. This experience contributed to a better understanding of multiple-use water management and also of joint management of water quality and quantity. (RĂ©sumĂ© d'auteur
Origins of the term nuées ardentes and the 1580 and 1808 eruptions of São Jorge Island, Azores
In this paper we: provide a brief account of the 1580 and 1808 eruptions on SĂŁo Jorge in the Azores, which produced Pyroclastic Density Currents (PDCs); discuss the first recorded use of the term nuĂ©es ardentes to describe these PDCs; trace how this term was introduced into the scientific literature and discuss its adoption by Alfred Lacroix (1863-1948) to describe the 'glowing clouds' produced by Mt. PelĂ©e (Martinique) in 1902. The 1580 and 1808 eruptions on SĂŁo Jorge are important because they provide early descriptions of PDCs. Documentary evidence of the eruptions and their impacts suggest that the 1580 PDC was a hotter flow, whereas the 1808 PDCs were cooler and more moist. Contemporary accounts describe the 1580 PDC as a 'globe of fire', mixed with 'caustic smoke' and moving at speed towards the bottom of the slope. In contrast, the 1808 PDCs comprised humid ash, were not incandescent and it is likely that the flows were cooler than that produced in 1580. Since the eruption of Mt. PelĂ©e in 1902, it has been widely accepted that the term nuĂ©es ardentes was introduced by Lacroix (1904), being based on his description of the pyroclastic flows that he witnessed. Lacroix acknowledges that the Portuguese expression, ardente nuvem was first used in contemporary accounts of the SĂŁo Jorge PDCs. This was first translated as nuĂ©e ardente and introduced into the scientific by the French geologist Ferdinand FouquĂ© (1828-1904), who was also Lacroix's father-in-law. Indeed, Lacroix provides an account of the 1580 and 1808 eruptions of SĂŁo Jorge in his 1904 work La Montagne PelĂ©e et ses Ăruptions. The seminal work of Frank Alvord Perret (1867-1943) on the 1929-32 eruptions of Mt. PelĂ©e and his description of nuĂ©es ardentes probably helped reinforce the association between the term and Mt. PelĂ©e
Short Term Variability of Evolved Massive Stars with TESS II: A New Class of Cool, Pulsating Supergiants
Massive stars briefly pass through the yellow supergiant (YSG) phase as they
evolve redward across the HR diagram and expand into red supergiants (RSGs).
Higher-mass stars pass through the YSG phase again as they evolve blueward
after experiencing significant RSG mass loss. These post-RSG objects offer us a
tantalizing glimpse into which stars end their lives as RSGs, and why. One
telltale sign of a post-RSG object may be an instability to pulsations,
depending on the star's interior structure. Here we report the discovery of
five YSGs with pulsation periods faster than 1 day, found in a sample of 76
cool supergiants observed by \tess at two-minute cadence. These pulsating YSGs
are concentrated in a HR diagram region not previously associated with
pulsations; we conclude that this is a genuine new class of pulsating star,
Fast Yellow Pulsating Supergiants (FYPS). For each FYPS, we extract frequencies
via iterative prewhitening and conduct a time-frequency analysis. One FYPS has
an extracted frequency that is split into a triplet, and the amplitude of that
peak is modulated on the same timescale as the frequency spacing of the
triplet; neither rotation nor binary effects are likely culprits. We discuss
the evolutionary status of FYPS and conclude that they are candidate post-RSGs.
All stars in our sample also show the same stochastic low-frequency variability
(SLFV) found in hot OB stars and attributed to internal gravity waves. Finally,
we find four Cygni variables in our sample, of which three are newly
discovered.Comment: 29 pages, 13 figures, 8 tables. Accepted for publication in ApJ.
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