Exclusive Seismoacoustic Detection and Characterization of an Unseen and Unheard Fireball Over the North Atlantic

Small meteoroids that enter Earth's atmosphere often go unnoticed because their detection and characterization rely on human observations, introducing observational biases in space and time. Acoustic shockwaves from meteoroid ablation convert to infrasound and seismic energy, enabling fireball detection using seismoacoustic methods. We analyzed an unreported fireball in 2022 near the Azores, recorded by 26 seismometers and two infrasound arrays. Through polarization analyses, array methods, and 3‐D ray‐tracing, we determined that the terminal blast occurred at 40 km altitude, ∼60 km NE of São Miguel Island. This location matches an unidentified flash captured by a lightning detector aboard the GOES‐16 satellite. The estimated kinetic energy is ∼10−3 kT TNT equivalent, suggesting a 10−1 m object diameter, thousands of which enter the atmosphere annually. Our results demonstrate how geophysical methods, in tandem with satellite data, can significantly improve the observational completeness of meteoroids, advancing our understanding of their sources and entry processes

Environmental representativity in marine protected area networks over large and partly unexplored seascapes

Converting assemblages of marine protected areas (MPAs) into functional MPA networks requires political will, multidisciplinary information, coordinated action and time. We developed a new framework to assist planning environmental representativity in a network across the marine space of Portugal, responding to a political commitment to protect 14% of its area by 2020. An aggregate conservation value was estimated for each of the 27 habitats identified, from intertidal waters to the deep sea. This value was based on expert-judgment scoring for environmental properties and features relevant for conservation, chosen to reflect the strategic objectives of the network, thus providing an objective link between conservation commitments and habitat representativity in space. Additionally, habitats' vulnerability to existing anthropogenic pressures and sensitivity to climate change were also scored. The area coverage of each habitat in Portugal and within existing MPAs (regionally and nationally) was assigned to a scale of five orders of magnitude (from 10%) to assess rarity and existing representation. Aggregate conservation value per habitat was negatively correlated with area coverage, positively correlated with vulnerability and was not correlated with sensitivity. The proposed framework offers a multi-dimensional support tool for MPA network development, in particular regarding the prioritization of new habitats to protect, when the goal is to achieve specific targets while ensuring representativity across large areas and complex habitat mosaics. It requires less information and computation effort in comparison to more quantitative approaches, while still providing an objective instrument to scrutinize progress on the implementation of politically set conservation targets.Agência financiadora Número do subsídio Oceanic Observatory of Madeira M1420-01-0145-FEDER-000001-OOM national funds through FCT UID/BIA/00329/2013 UID/Multi/04326/2013 Fundacao para a Ciencia e a Tecnologia SFRH/BPD/95334/2013 CESAM - FCT/MEC through national funds UID/AMB/50017 - POCI-01-0145-FEDER-007638 FEDER FCT SFRH/BPD/94320/2013 MARE - UID/MAR/04292/2019 EU through the Cohesion Fund POSEUR-03-2215-FC-000046 POSEUR-03-2215-FC-000047 FCT national funds ECO/28687/2017info:eu-repo/semantics/publishedVersio

Eruptive sequences of Fogo and Furnas volcanoes between Ribeirinha and Lomba da Maia (São Miguel, Azores)

Resumo: A realização de novos cortes estratigráficos na costa norte da zona central da ilha de São Miguel (Açores), entre a Ribeirinha e a Lomba da Maia, permitiu melhorar o conhecimento das sequências eruptivas dos flancos norte dos vulcões do Fogo e das Furnas. Definiram-se três grandes unidades vulcanoestratigráficas, considerando critérios espácio-temporais, e focou-se o estudo nos produtos de erupções subaéreas explosivas. No porto de Santa Iria (Ribeirinha) e na praia da Viola (Lomba da Maia) observaram-se importantes ignimbritos, integrados na Unidade de Base. Na Unidade Intermédia definiu-se a nova Formação de São Brás e complementaram-se dados estratigráficos das formações do Porto Formoso, Chã das Gatas e Coroa da Mata. A subdivisão da Formação da Chã das Gatas em Sequência do Calhau do Cabo e Sequência da Defeira permitiu atribuir a esta última uma idade relativa de 21 340 a 18 600 anos B.P. Na Unidade Recente incluíram-se os depósitos dos últimos 5 000 anos.Abstract: The documentation of exposures of volcanic products in the north coast of São Miguel Island (Azores), between Ribeirinha and Lomba da Maia, allowed to improve the knowledge of the eruptive sequences of the northern flanks of Fogo and Furnas volcanoes. Three main volcano-stratigraphic units were defined, based on spatial-temporal criteria, and the study was mainly focused on the products of subaerial explosive eruptions. At Santa Iria port (Ribeirinha) and at Viola beach (Lomba da Maia) important ignimbrites were observed and integrated in the Base Unit. In the Intermediate Unit the new São Brás Formation was defined and new stratigraphic data allowed to complement Porto Formoso, Chã das Gatas and Coroa da Mata formations. The Chã das Gatas Formation was subdivided into Calhau do Cabo and Defeira sequences, allowing to constrain the age of the Defeira Sequence between 21,340 and 18,600 years B.P. The deposits of the last 5,000 years were included in the Recent Unit.info:eu-repo/semantics/publishedVersio

Earthquakes and Volcanic Activity on Islands. History and Contemporary Perspectives from the Azores

This volume examines the impact of and responses to historic earthquakes and volcanic eruptions in the Azores. Study is placed in the contexts of: the history and geography of this fascinating archipelago; progress being made in predicting future events and policies of disaster risk reduction. This is the only volume to consider the earthquake and volcanic histories of the Azores across the whole archipelago and is based, not only on contemporary published research, but also on the detailed study of archival source materials. The authors seek to show how extreme environmental events, as expressed through eruptions, earthquakes and related processes operating in the past may be considered using both complementary scientific and social scientific perspectives in order to reveal the ways in which Azorean society has been shaped by both an isolated location in the middle of the Atlantic Ocean and the ever present threat of environmental uncertainty. Chapter 2, which analyses in depth the geology and tectonics of the islands is of more specialist interest, but technical terms are fully explained so as to widen the accessibility of this material. The audience for this volume includes all those who are interested in the geology, geography, history and hazard responses in the Azores. It is written, not just for the educated general reader, but for the specialist earth scientist and hazard researcher

Fogo Volcano (São Miguel, Azores): a hazardous edifice

Le volcan Fogo, le plus grand des trois volcans actifs sur l’île São Miguel dans les Açores, montre une variété d’aléas qui sont liés à des processus non éruptifs. Souvent nommés aléas volcaniques indirects, ils sont, sur le Fogo, le produit d’interactions entre l’édifice volcanique instable et les processus contrôlés par des mécanismes sismiques, hydrothermaux, gravitaires et hydrologiques. Il s’avère que de nombreuses maisons, routes et ponts sont en danger si une activité séismique importante se manifestait. Or, depuis que l’île a été colonisée, les tremblements de terre supérieurs à IX sur l’échelle européenne macrosismique (EMS 98) ont frappé en 1522, 1713, 1811 et 1935. Environ 45 000 personnes habitent dans le district de Fogo et, si aucune action pour réduire la vulnérabilité n'est mise en place, des dommages seront inévitables dans le futur. Des gaz sont émis à plusieurs endroits sur le Fogo et, parmi eux, le CO2 est un gaz dangereux quand il se concentre dans des dépressions. Des concentrations supérieures à 15 % conduisent souvent à l’asphyxie et à la mort, aussi les risques induits par les émissions de gaz représentent-ils un danger important pour les habitants du Fogo. Au cours des cinq derniers siècles, l’île São Miguel a été affectée par plusieurs glissements de terrain destructeurs et des crues soudaines qui ont été provoqués par des tremblements de terre, des éruptions volcaniques et des périodes de fortes pluies. Parmi ceux-ci, un événement de grande magnitude (X, EMS 98) en octobre 1522 a produit une coulée boueuse qui a complètement détruit la ville de Vila Franca do Campo. Environ 5000 habitants furent tués et une surface de 4,5 km2 fut recouverte par des millions de mètres cubes de matériel. Les aléas volcaniques indirects sont une menace constante pour les habitants du volcan Fogo, mais ce n’est que récemment que des recherches approfondies leur sont consacrées.Fogo volcano, the largest of the three active volcanoes of São Miguel Island in the Azores, presents a range of hazards, which are related to non-eruptive processes. Often termed indirect volcano hazards, these are the focus of the present paper and on Fogo volcano are produced by interactions between the unstable volcanic edifice and processes controlled by seismic, hydrothermal, slope instability and hydrological processes. Many houses, roads and bridges are at risk should significant earthquake activity occur. Since the island was settled in the 15th century, earthquakes exceeding IX on the European Macroseismic Scale (i.e. EMS 98) have struck São Miguel in 1522, 1713, 1811 and 1935. An estimated 45,000 people live within the Fogo District and, without action to reduce vulnerability, future losses are inevitable. Gases are emitted from several locations on Fogo, and CO2 is a dangerous gas when it ponds in depressions. Concentrations of over 15% often lead to asphyxiation and death, and case studies of the hazards posed by gas discharge are presented. São Miguel has been affected by several destructive landslides and flash floods in the last five centuries, triggered by earthquakes, volcanic eruptions or periods of heavy rainfall. A large (X, EMS 98) earthquake in October 1522 generated a debris flow that buried and completely destroyed the town of Vila Franca do Campo. About 5,000 people were killed and an area of ~4.5 km2 was covered by millions of cubic metres of debris. Indirect volcanic hazards are an ever-present threat to people living on the Fogo Volcano, yet until recently they have been little researched

Responses to, and the short and long-term impacts of, the 1957/1958 Capelinhos volcanic eruption and associated earthquake activity on Faial, Azores

The 1957/58 Capelinhos eruption on Faial Island in the Azores is well known for being an excellent example of Surtseyan hydromagmatic volcanic activity. Less well known are the responses of the Portuguese authorities to the eruption and subsequent earthquake in May 1958, and the ways in which well-thought-out and generally effective recovery programmes were put in place. At the time Portugal was ruled by a dictatorship, the Estado Novo (New State). Only superficially similar to other fascist governments in Southern Europe, the Estado Novo collected huge amounts of data on the responses of the authorities to the disaster and their programmes of recovery, but never encouraged academic evaluation of policy, although it ensured that the scientific aspects of the eruption and earthquake were meticulously recorded and published.\ud \ud In this paper we remedy this situation by discussing the details of the immediate response to the emergency and the ways in which the island recovered in its aftermath. The study is based not only on archival sources and demographic and economic data, but also on detailed interviews with survivors some of whom were also decision makers. We argue that response, recovery and rehabilitation were generally highly successful and assess the lessons of the 1957/58 emergency which are relevant to future geophysical disasters in Faial and the wider Azores. Since the 1974 revolution Portugal has been a democratic state. We conclude that both the legislation and the civil defence infrastructure, necessary to achieve a similarly strong and successful response, are in place today

Changing hazard awareness over two decades: the case of Furnas, São Miguel (Azores)

Furnas (c. 1500 inhabitants) lies within the caldera of Furnas volcano on the island of São Miguel (Azores) and has the potential to expose its inhabitants to multiple hazards (e.g. landslides, earthquakes, volcanic eruptions and degassing). The present population has never experienced a volcanic eruption or a major earthquake, although the catalogue records six eruptions, sub-Plinian in style, over the last 2 kyr. Today, the area experiences strong fumarolic activity. In the case of an eruption, early evacuation would be necessary to prevent inhabitants from being trapped within the caldera. An awareness of potential threats and knowledge of what to do in the case of an emergency would assist in evacuation. In this paper, inhabitants’ awareness of volcanic and seismic threats in 2017 is compared with that revealed in a similar study completed more than two decades ago. It is concluded that whereas awareness of earthquakes and the dangers posed by volcanic gas discharge has increased, knowledge of the threat of volcanic eruptions and the need to prepare for possible evacuation has not. Research suggests that the changing awareness is related to effective collaboration that has developed between the regional government, through its civil protection authorities and scientists, and the people of Furnas