Chapter 16 Volcanic hazard vulnerability on São Miguel Island, Azores

AbstractIn recent years much progress has been made in researching a wide variety of extreme events on São Miguel. In addition there are a number of volcano-related risks that impact upon the people of São Miguel. Some of these may occur both before and during volcanic emergencies (e.g. earthquakes), whilst others render São 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 São 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

Non-eruptive geological hazards of dormant volcanoes: Sao Miguel, Azores Perigos geologicos nao erurptivos en vulcoes adormecidos: Sao Miguel, Acores

São 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

Volcanic hazard vulnerability on Sao Miguel Island, Azores

"In recent years much progress has been made in researching a wide variety of extreme events on S. Miguel. In addition there are a number of volcano-related risks which impact upon the people of S. Miguel. Some of these may occur both before and during volcanic emergencies (e.g. earthquakes), whilst others render S. Miguel dangerous even when its volcanoes are not erupting (e.g. flooding, landslides, tsunamis and health impacts, especially the effects of CO2 seepage into dwellings). In this chapter we first define what vulnerability means to the people of São 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; c. social and cultural and perceptual (i.e. do people have an accurate cognition of risk). Particular areas of concern relate to housing; the identification of isolated dwellings which 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.

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 São Jorge in the Azores, which produced Pyroclastic Density Currents (PDCs); discuss the first recorded use of the term nuées 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. Pelée (Martinique) in 1902. The 1580 and 1808 eruptions on São 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. Pelée in 1902, it has been widely accepted that the term nuées 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 São Jorge PDCs. This was first translated as nuée ardente and introduced into the scientific by the French geologist Ferdinand Fouqué (1828-1904), who was also Lacroix's father-in-law. Indeed, Lacroix provides an account of the 1580 and 1808 eruptions of São Jorge in his 1904 work La Montagne Pelée et ses Éruptions. The seminal work of Frank Alvord Perret (1867-1943) on the 1929-32 eruptions of Mt. Pelée and his description of nuées ardentes probably helped reinforce the association between the term and Mt. Pelée

The role of religion in shaping responses to earthquakes and volcanic eruptions: a comparison between Southern Italy and the Azores, Portugal

In contrast to the situation only a few years ago, the case for religion being accepted as a vital element in the cultural responses to disasters has been largely accepted by both academic writers and international agencies, such as the International Federation of Red Cross and Red Crescent Societies. Religions are far more varied in their approaches to natural catastrophes than is frequently recognised or acknowledged by academic writers who are trained and socialised within a 'western' post-Enlightenment tradition. In this paper we seek to demonstrate how detailed religious responses to earthquakes and volcanic eruptions vary even between two societies, southern Italy and the Azores, which are broadly similar in terms of their southern European Catholic religiosity. In southern Italy, popular Catholicism has conflated two approaches to theodicy: the retributive and the Augustinianism (i.e. free-will). Divine wrath may be propitiated through piety and Christian action, which includes worship, repentance, changed conduct and is often associated with well-choreographed ritualistic actions, some of the latter being far removed from Catholic orthodoxy. Such reactions to disaster are not confined to the past but remain strongly embedded in present-day practice. In the Azores a combination of: a history of a better educated and more enlightened church leadership; greater emphasis on praxis following disasters; the growth of the distinctive, egalitarian and pastorally focused Cult do Esparto Santo (i.e. Cult of the Holy Spirit) and the spread of alternative models of theodicy through educational outreach, has produced a strongly contrasting religious response. We conclude that, in the case of the Azores the religious milieu favours active collaboration between the Catholic faith community and the Civil Defence authorities in the aftermath of disasters, whereas this is not the case in southern Italy, although there are some recent signs of change

The older volcanic complexes of Sao Miguel, Azores: Nordeste and Povoacao

The oldest part of S. Miguel is to the east of Furnas. Previous research argued that these volcanics belong to a construct called the Nordeste Volcano, a heavily eroded shield which not only extends to the east coast of the island but also underlies Furnas Volcano in the west. On the basis of geomorphological mapping, we argue that Nordeste comprises two volcanic systems: an older Nordeste construct (the Nordeste Volcanic System); and the younger Povoação Volcano which straddles the Nordeste shield on its western margin. The Nordeste Volcanic System consists of the Lower Basalts which constitute the overwhelming majority of its subaerial products which are exposed in coastal cliff sections. Above the Lower Basalts is a surficial drape of Ankaramites and the Upper Basalts. There is no evidence of large explosive trachytic eruptions from Nordeste Volcanic System. Povoação Volcano comprises an early shield construct, after which the volcano experienced caldera collapse. Post-caldera deposits are poorly exposed, but include basaltic, mugearitic and trachytic lavas intercalated by cut and fill sequences. Radiometric dating has yet to resolve fully the absolute ages of the Nordeste and Povoação volcanic systems, but morphology indicates that the former is much older than the latter

Phosphorus mobilizing consortium Mammoth P enhances plant growth

Global agricultural productivity may be constrained by the finite and limited supply of phosphorus (P), adding to the challenges in meeting the projected needs of a growing human population in the coming decades. In addition, when P fertilizers are added to soils, they can become bound to soils resulting in low fertilizer efficiency. However, P-mobilizing bacteria could potentially liberate soil-bound P, resulting in a higher plant P uptake and increased yield. Bacteria can mobilize P through several mechanisms, suggesting that consortia of P-bacteria may be more effective than single species. Species diversity can have a synergistic, or non-additive, effect on ecosystem functioning (&quot;the whole is more than the sum of its parts&quot;) but rarely is the microbial community structure intentionally managed to improve plant nutrient uptake. We investigated whether inoculation of soils with a four-species bacterial community developed to mobilize soil P could increase plant productivity. In wheat and turf trials, we found that Mammoth P was able to deliver yields equivalent to those achieved using conventional fertilizer applications. Herbs and fruits showed that the combination of fertilizer with Mammoth P significantly increased productivity -in some cases productivity doubled. Metabolites produced by the Mammoth P consortium led to increased yields in some cases, suggesting that microbial products (produced in the absence of plants) played a role in enhancing plant productivity. Results from these trials indicate substantial potential of Mammoth P to enhance P supply to plants, improving P fertilizer use-efficiency and increasing agricultural productivity. 19 Agricultural productivity may be constrained in the 21 st Century by the finite supply of global a 20 phosphorus (P), adding to the challenges in meeting the projected needs of a growing human population 21 in the coming decades. In addition, when P fertilizers are added to soils, they can become bound to soils 22 resulting in low fertilizer efficiency. However, bacteria have the ability to mobilize soil bound P through 23 several mechanisms potentially resulting in a higher plant P uptake and increased yield. Furthermore, 24 species diversity can have a synergistic effect on ecosystem functioning (&quot;the whole is more than the sum 25 of its parts&quot;) suggesting that bacterial communities, or consortia, may be more effective than single 26 species. However, in agriculture management practices, rarely is the soil microbial community structure 27 effectively manipulated to improve plant nutrient uptake. We investigated whether inoculation of soils 28 with a bacterial consortium developed to mobilize soil P named Mammoth P could increase plant 29 productivity. In turf, herbs and fruits, we showed that the combination of conventional inorganic fertilizer 30 combined with Mammoth P increased productivity up to twofold compared to the fertilizer treatments 31 without the Mammoth P inoculant. In wheat trials, we found that Mammoth P by itself was able to deliver 32 yields equivalent to those achieved with conventional inorganic fertilizer applications. The metabolites 33 produced by the consortium in Mammoth P likely played a role in enhancing plant productivity. Results 34 from this study indicate the substantial potential of Mammoth P to enhance P supply to plants, improving 35 P fertilizer use-efficiency and increasing agricultural productivity. 3

Denitrification and nitrous oxide emissions from riparian forests soils exposed to prolonged nitrogen runoff

Compared to upland forests, riparian forest soils have greater potential to remove nitrate (NO3) from agricultural run-off through denitrification. It is unclear, however, whether prolonged exposure of riparian soils to nitrogen (N) loading will affect the rate of denitrification and its end products. This research assesses the rate of denitrification and nitrous oxide (N2O) emissions from riparian forest soils exposed to prolonged nutrient run-off from plant nurseries and compares these to similar forest soils not exposed to nutrient run-off. Nursery run-off also contains high levels of phosphate (PO4). Since there are conflicting reports on the impact of PO4 on the activity of denitrifying microbes, the impact of PO4 on such activity was also investigated. Bulk and intact soil cores were collected from N-exposed and non-exposed forests to determine denitrification and N2O emission rates, whereas denitrification potential was determined using soil slurries. Compared to the non-amended treatment, denitrification rate increased 2.7- and 3.4-fold when soil cores collected from both N-exposed and non-exposed sites were amended with 30 and 60 μg NO3-N g-1 soil, respectively. Net N2O emissions were 1.5 and 1.7 times higher from the N-exposed sites compared to the non-exposed sites at 30 and 60 μg NO3-N g-1 soil amendment rates, respectively. Similarly, denitrification potential increased 17 times in response to addition of 15 μg NO3-N g-1 in soil slurries. The addition of PO4 (5 μg PO4–P g-1) to soil slurries and intact cores did not affect denitrification rates. These observations suggest that prolonged N loading did not affect the denitrification potential of the riparian forest soils; however, it did result in higher N2O emissions compared to emission rates from non-exposed forests

Linear stability analysis of retrieval state in associative memory neural networks of spiking neurons

We study associative memory neural networks of the Hodgkin-Huxley type of spiking neurons in which multiple periodic spatio-temporal patterns of spike timing are memorized as limit-cycle-type attractors. In encoding the spatio-temporal patterns, we assume the spike-timing-dependent synaptic plasticity with the asymmetric time window. Analysis for periodic solution of retrieval state reveals that if the area of the negative part of the time window is equivalent to the positive part, then crosstalk among encoded patterns vanishes. Phase transition due to the loss of the stability of periodic solution is observed when we assume fast alpha-function for direct interaction among neurons. In order to evaluate the critical point of this phase transition, we employ Floquet theory in which the stability problem of the infinite number of spiking neurons interacting with alpha-function is reduced into the eigenvalue problem with the finite size of matrix. Numerical integration of the single-body dynamics yields the explicit value of the matrix, which enables us to determine the critical point of the phase transition with a high degree of precision.Comment: Accepted for publication in Phys. Rev.

Comparative behaviour and evolution of the caldera forming active volcanoes of Sao Miguel (Azores): Sete Cidades, Fogo and Furnas

São Miguel, with its E-W elongated shape, is the largest and the most volcanically active of the nine islands of the Azores archipelago. From West to East Sete Cidades, Fogo and Furnas are three active central volcanoes with calderas. Each of these three calderas evolved through several phases of collapse generated by Plinian scale explosive eruptions over the last 40 ka. The most recent Plinian scale eruption was that of Fogo A, c. 5ka, from Fogo volcano. In this report, we summarise the results of more than two decades of research on the geology of these volcanoes. More specifically we compare: the evolution of each caldera; and the styles of recent eruptions. It is of note that there is a pattern of a change in eruptive behaviour from around 5 ka shown by all three volcanoes to eruptions displaying a style involving switching between magmatic and phreatomagmatic sub-Plinian activity. This is well displayed in the historic sub-Plinian eruptions of Fogo and Furnas