Jose M. R. Pacheco

IVAR - Instituto de Investigação em Vulcanologia e Avaliação de Riscos

Volcanic clouds pose significant threats to air traffic, human health, and economic activity, making early detection and monitoring crucial. Accurate determination of eruptive source parameters is crucial for forecasting and implementing preventive measures. This review article aims to identify the most common remote sensing methods for monitoring...

Abstract: "Volcanic eruptions are natural disasters that can have severe impacts on human life both locally and globally. Remote sensing using satellites enables the monitoring and tracking of volcanic clouds, even in locations with difficult or no access, and helps determine eruption source parameters (e.g., erupted volume, plume height, and mass...

Aethalometer measurements were carried out at the Atmospheric Observatory of Izaña (IZO) during the eruption of Cumbre Vieja volcano on the island of La Palma to study the impact of volcanic ash in aethalometer signals. Principal Component Analyses of the back trajectories arriving at IZO showed that more than 53% of the variance of equivalent BC (...

Volcanic clouds are a major hazard to air traffic, public health, infrastructure, and economic sectors. Therefore, monitoring and tracking volcanic clouds and determining eruptive source parameters (e.g., erupted volume, plume height, mass eruption rate) is crucial to characterizing eruption dynamics and assessing associated natural hazards. A lite...

Abstract: The last eruption in the Fogo Volcano, which began in November 2014, was the first eruptive event captured by the Sentinel-1 (S1) mission. The present work sought to complement previous research and explore the potential of utilizing data from the Synthetic Aperture Radar (SAR) S1 mission to better monitor active volcanic areas. S1 Ground...

Ignimbrites are relatively uncommon on ocean island volcanoes and yet they constitute a significant portion of the stratigraphy of Terceira Island (Azores). The Lajes-Angra Ignimbrite Formation (ca. 25 cal ka BP) contains the youngest ignimbrites on Terceira and records two ignimbrite-forming eruptions of Pico Alto volcano that occurred closely spa...

The Azores Archipelago is one of the most active volcanic areas in the North Atlantic region. Approximately 30 eruptions have been reported over the last 600 years with some major VEI 5 (Volcanic Explosivity Index) eruptions further back in time. The geochemical composition of associated tephra‐derived glass, however, is not well characterized. An...

It is well known that explosive volcanic eruptions pose serious hazards to local communities and may have worldwide impacts. However, the products of explosive eruptions on volcanic ocean islands are almost inevitably incompletely preserved as a significant portion of the erupted material is deposited into the ocean, thereby impeding our ability to...

Explosive eruptions are understood as complex natural phenomena capable of causing significant socioeconomic and climatic impact. During Plinian or sub-Plinian eruptions tephra is ejected into the atmosphere and dispersed by the wind, sometimes threatening human lives and infrastructures. Fogo Volcano (São Miguel Island) is one of the most hazardou...

O projeto HABAIR propõe o conceito de uma plataforma híbrida aérea, combinando um balão de alta altitude (HAB) com um veículo aéreo não tripulado (UAV), para realizar missões de longo alcance verticais e horizontais onde a entrega precisa da carga útil ou a sua recuperação são importantes. A solução proposta consiste num HAB que transportará passiv...

Sete Cidades is an active yet dormant central volcano located in the westernmost part of São Miguel Island (Azores archipelago), characterized by a 5-km-wide multi-stage caldera formed in the last 36 ka. In this work, we present new stratigraphic, grain size, petrographic, and geochemical data of the 16 ka Santa Bárbara Formation, related to the la...

High-resolution bathymetric data and seafloor sampling were used to characterize the most recent volcanic eruption in the Azores region, the 1998–2001 Serreta submarine eruption. The vent of the eruption is proposed to be an asymmetric topographic high, composed of two coalescing volcanic cones, underlying the location where lava balloons had been...

Sete Cidades is the westernmost central volcano on São Miguel island, Azores. Although currently dormant, it has been the most active volcano in the past 20 kyr. The largest eruption took place approx. 16 kyr ago and enlarged the summit caldera. The related deposits consist of unwelded pyroclastic density current (PDC) deposits on most flanks of th...

Ignimbrites are relatively uncommon on ocean island volcanoes and yet they are found on three islands of the Azores. Terceira has a stratigraphic record of at least seven major ignimbrite-bearing formations dated between 86 and 21 ka, which makes it the Azorean island with the greatest erupted volume of ignimbrite. These ignimbrite formations can r...

Fogo volcano is located in the central part of S. Miguel Island (Azores) and is an active central volcano with summit caldera partly occupied by a lake. Similarly to the other two active central volcanoes on the island, also with summit calderas and lakes, the recent eruptive history of Fogo volcano (last 5 ky) is dominated by explosive eruptions o...

The assessment of volcanic hazards in oceanic islands with active volcanoes is vital for land management and emergency planning. The volcanic history of São Miguel shows that it is the most active island of the Azores, with the highest eruptive frequency of subplinian and plinian events, counting at least 33 explosive eruptions in the last 5000 yea...

The recent (< 100 ka) volcanic stratigraphy of Terceira, Azores, includes at least seven peralkaline trachytic ignimbrite formations, attesting to a history of explosive eruptions. In this study, the petrogenesis and pre-eruptive storage conditions of the ignimbrite-forming magmas are investigated via whole-rock major and trace element geochemistry...

When teaching at a non-English language university, we often argue that because English is the international language, students need to become familiar with English terms, even if the bulk of the class is in the native language. However, to make the meaning of the terms clear, a translation into the native language is always useful. Correct transla...

From a social perspective, geological risks are increasingly important and the more so as more human, economic and technological activities occur in the areas of influence of these risks. The island of Faial was the scene of a surtseiana eruption in 1957/58, in Capelinhos, with a dramatic impact on the island. The quality of the information availab...

Furnas is one of three active central volcanoes on São Miguel Island, Azores, and is considered to be one of the most hazardous in the archipelago. In this study, the pre-eruptive magma plumbing system of the 10 young (<5 ka), intra-caldera, sub-Plinian, trachytic eruptions of the Upper Furnas Group (UFG) is investigated via whole rock major and tr...

RED SEED stands for Risk Evaluation, Detection and Simulation during Effusive Eruption Disasters, and combines stakeholders from the remote sensing, modelling and response communities with experience in tracking volcanic effusive events. The group first met during a three day-long workshop held in Clermont Ferrand (France) between 28 and 30 May 201...

Faial is one of the nine islands that form the Azores archipelago in the North Atlantic, characterized by a complex geodynamic setting dominated by the triple point where the North American, Eurasian, and African lithospheric plates meet. Faial Island comprises two central volcanoes and two basaltic fissure systems. The oldest central volcano is th...

Furnas is the easternmost of the trachytic active central volcanoes of Sa˜o Miguel. Unlike the other central volcanoes, Sete Cidades and Fogo, Furnas does not have a substantial edifice built up above sea-level. Although not as dominant as the other two volcanoes, Furnas does, however, have an edifice rising from the basal basaltic lavas exposed on...

São Miguel Island comprises five active volcanic systems, including three central volcanoes with calderas and two basaltic fissure systems. Volcanic eruptions in São Miguel are of basaltic and trachytic nature (s.l.), including Hawaiian, Strombolian, sub-Plinian, Plinian and Vulcanian events, the more explosive ones frequently including hydromagmat...

The ~1000-years BP eruption of Caldeira Volcano (Faial Island) was one of the last major explosive events recorded in the Azores. It produced a complex succession of pyroclastic deposits, known as the C11, divided into three members. At the base is the Brejo Member, a sequence of fine to coarse-grained parallel-bedded ash layers found in the NW sec...

Furnas volcano is a nested caldera complex on São Miguel island, Azores. The magmatic system of Furnas was investigated via whole-rock major and trace element geochemistry, mineral chemistry and thermobarometry. Three distinct stages in the recent (< 30 ka) history of Furnas volcano were targeted; the outer caldera-forming Povoação Ignimbrite Forma...

The ~1 ka eruption of Caldeira Volcano (C11 eruption) on Faial Island was the last caldera-forming event in the Azores archipelago. This explosive eruption produced widespread pyroclastics (erupted volume of ~0.2 km3) that affected much of the small island of Faial and was responsible for collapse of the ~2 km-wide summit caldera. Here, we describe...

Faial is one of the most volcanically active islands of the Azores Archipelago. Historical eruptions occurred on the Capelo Peninsula (westernmost sector of the island) during A.D. 1672–1673 and more recently in A.D. 1957–1958. The other exposed volcanic products of the peninsula are so far loosely dated within the Holocene. Here, we present a succ...

The relationships between tectonics and hotspot-related magmatism in transform/ transtensive settings are poorly known. The Azores archipelago, lying where the transform plate boundary between the Nubian and Eurasian plates meets the Mid-Atlantic Ridge, is a rare site to investigate these relationships. The distinct tectono-magmatic features of Fai...

Furnas, São Miguel, Azores is an oceanic-island caldera volcano characterised by mafic to silicic, metaluminous to peralkaline magmas, and a range of eruption styles that imply significant variation in pre- and syn-eruptive processes. Here, we investigate these processes and provide insights into the magma plumbing system of Furnas by targeting sel...

High-resolution morpho-bathymetric data at 1:200,000 scale obtained during the FAIVI cruise (2011) and the resulting geomorphologic map of the Terceira island offshore area (central Azores, Portugal) are presented for the first time. The uneven morphology around Terceira is primarily related to volcanic features, such as linear and cone-shaped erup...

Magmas in Faial Island, Azores (Portugal), were mostly erupted from two fissure zones and the Caldeira central volcano during overlapping periods. The fissure zones follow extensional trends oriented WNW and ESE and erupted nepheline- to hypersthene-normative basalts and hawaiites. The Caldeira central volcano builds the central part of the island,...

Between December 1998 and April 2001, a submarine basaltic eruption occurred west of Terceira Island, Azores (Portugal) in water depths between 300 and 1,000 m. Physical evidence for the eruption was provided by the periodic occurrence of hot lava “balloons” floating on the sea surface. The balloons consisted of a large gas-filled cavity surrounded...

The Azores Islands are located on the triple junction involving Eurasian, Nubian and North American plates. Faial is the nearest island to the Atlantic Ridge and one of the most active, with the 1957-58 Capelinhos eruption and the 1998 earthquake. Faial consists of three main structural features: a well exposed graben structure (eastern sector), a...

The 1998-2001 submarine Serreta eruption brought to science a new challenge. This eruption took place offshore of Terceira Island (Azores), on the so-called Serreta Submarine Ridge, corresponding to a basaltic fissure zone with alkaline volcanism, within a tectonic setting controlled by an hyper-slow spreading rift (the Terceira Rift). The inferred...

The 1000 year-old eruption of the Caldeira volcano (Faial Island, Azores) generated extensive pyroclastic density currents (PDCs) and was responsible for the subsidence of the 2-km-wide summit caldera. The stratigraphic sequence of this eruption has been studied in detail and emplacement temperatures of PDCs have been estimated by paleomagnetic ana...

Ignimbrites are relatively rare on mid-oceanic volcanic islands, but they occur on at least three of the nine Azorean islands—São Miguel, Faial, and Terceira. Ignimbrites on Terceira, which are mostly comenditic trachyte in composition, constitute a signifi cant portion of the island’s volcanic stratigraphy exposed primarily in cliff sections along...

The interpretation of volcanic eruptions is usually derived from direct observation and the thorough analysis of the deposits. Processes in vent-proximal areas are usually not directly accessible or likely to be obscured. Hence, our understanding of proximal deposits is often limited as they were produced by the simultaneous events stemming from pr...

Most volcanic eruptions on Earth take place in submarine settings, still, only a small fraction are emergent or possibly observed at the sea surface. Between December 1998 and April 2001, a submarine eruption occurred 10 km west of Terceira Island, Azores (Portugal) and was observable at the sea surface due to the periodic occurrence of "lava ballo...

Pyroclastic density currents are hot mixtures of volcanic particles and gas that flow at high speed along the topography. They are the most hazardous and destructive volcanic phenomena, responsible for thousands of fatalities over the last centuries. It is therefore essential to assessment the areas susceptible of being affected and the impact on p...

São Miguel, the biggest island of the Azores archipelago, accommodates three presently quiescent central volcanoes (Sete Cidades, Fogo, Furnas), connected by basaltic fissure systems. Sete Cidades volcano, located in the western part of the island, is nearly 900 m asl high, has a basal diameter of approx. 15 km (at sea level), and hosts a summit ca...

Most volcanic eruptions on Earth take place in submarine settings, still, only a small fraction are emergent or possibly observed at the sea surface. Between December 1998 and April 2001, a submarine eruption occurred 10 km west of Terceira Island, Azores (Portugal) and was observable at the sea surface due to the periodic occurrence of "lava ballo...

The syn-eruptive and post-eruptive history of São Roque tuff cone, its geological setting and volcanological features were studied in detail to understand the role played by the different factors that contributed to the morphological evolution of this relatively simple and small volcanic edifice. In addition, attention was also focused on the serie...

The Azores archipelago lies in the junction of the North-American, African and Eurasian lithospheric plates. The geodynamical setting is therefore complex and, consequently this area is affected by intense seismic and volcanic activity. This study addressed the coastal geology of four Azorean islands: Santa Maria, Graciosa, Flores and Corvo. The co...

We propose a long-term volcanic hazards event tree for Teide-Pico Viejo stratovolcanoes, two complex alkaline composite volcanoes that have erupted 1.8–3 km3 of mafic and felsic magmas from different vent sites during the last 35 ka. This is the maximum period that can be investigated from surface geology and also represents an upper time limit for...

The deposits of three eruptions in the last 5000 years are described in detail in order to constrain eruptive parameters and allow a quantitative assessment of the hazard from a range of explosive eruption types at Sete Cidades volcano, São Miguel, Azores. These deposits include: the Caldeira Seca eruption (P17) which occurred around 600 yr BP, whi...

Sete Cidades is a central volcano with a summit caldera at the western end of São Miguel Island, Azores. Its stratigraphy comprises two main geological groups: the Inferior Group, the units of which date from more than 200 000 years ago through to 36 000 years before present, consisting of thick lava flows and subaerial volcaniclastic deposits that...

The dynamics of explosive volcanic activity at Sete Cidades Volcano (S. Miguel, Azores) were analyzed by using multiphase flow simulations. Sete Cidades, located on the western end of S. Miguel Island, is an active central volcano truncated by an approximately circular caldera of about 5 km in diameter, with steep walls ranging up to 500 m high. In...

On July 9th 1998 an earthquake with magnitude ML=5.8 struck Faial Island producing large damage in some villages. The town of Horta was slightly affected. A study on the characteristics of the shallower layers was developed, within the scope of the COMICO project, using ambient vibrations analysis. A detailed study of the surface geology was also p...

Sete Cidades volcano forms the Western part of the island of São Miguel, Azores, which is hosting three active trachytic central volcanoes (Sete Cidades, Fogo, Furnas). Volcanic activity in the archipelago exhibits a strong tectonic control and on São Miguel, the NW-SE trending basaltic Terceira Rift is intersecting the central volcanoes. All three...

Sete Cidades volcano forms the Western part of the island of São Miguel, Azores, which is hosting three active trachytic central volcanoes (Sete Cidades, Fogo, Furnas). Volcanic activity in the archipelago exhibits a strong tectonic control and on São Miguel, the NW-SE trending basaltic Terceira Rift is intersecting the central volcanoes. All three...

Explosive volcanic eruptions inject great amounts of tephra into the atmosphere. The dispersal of volcanic plumes results from the interaction between the atmospheric conditions and the characteristics of the plume itself. Characterisation of the wind fields in the Azores region provides critical input parameters for existing tephra fallout dispers...

Sete Cidades is an active central volcano with an approximately circular summit caldera located on the western part of S. Miguel Island. Inside the caldera there are pumice cones, maars and domes, while the dominant structures on the outer slopes are scoria cones and domes. The stratigraphy of Sete Cidades Volcanic Complex is divided in two main gr...

During 25-28 July 2003 the US Navy submarine NR-1 dove on the seamount D. Joao de Castro Bank, compiling reconnaissance sonar and visual data. Castro Bank sits along strike and between the eastern Azorian islands of Terceira and S. Miguel, occupying a seismically active region ˜60 km from each of these islands and apparently controlled by the same...

In December 1998 a volcanic eruption started about 10 km W of Terceira Island, Azores, on the so-called Terceira Rift. The eruptive vents were located in the Serreta Submarine Ridge, at depths ranging from 300 to 1000 meters. The observed eruption was preceded by a small seismic crisis, and lasted for more than two years. The tectonic setting of th...

The 1957–1958 eruption of Capelinhos, Faial island, Azores, involved three periods of surtseyan, hydromagmatic activity: two in 1957 and one in 1958. Deposits from this eruption are exposed both in sea cliffs cut into the flanks of the tuff cone and more distally >1 km from the vent. Five lithofacies are identified: lithofacies I is composed of eve...

Furnas is the easternmost of the three active central volcanoes on the island of São Miguel in the Azores. Unlike the other two central volcanoes, Sete Cidades and Fogo, Furnas does not have a well-developed edifice, but consists of a steep-sided caldera complex 8×5 km across. It is built on the outer flanks of the Povoação/Nordeste lava complex th...

Explosive volcanic activity has been dominant throughout the history of Furnas volcano. Eruptions that switched between magmatic and phreatomagmatic activity have become typical in the more recent history of the volcano with 70% of the eruptions in the last 5000 years being of this style. It is thus likely that future eruptions will be of this type...

The Povoação Ignimbrite Formation (PIF) was emplaced by one of the larger explosive trachytic eruptions of Furnas Volcano, São Miguel, Azores. Trachytic ignimbrites are common in the products of Furnas Volcano and examples of welding occur in at least three ignimbrites of which the Povoação Ignimbrite is the most extensive. The PIF may correlate wi...

RESUMO A estratigrafia dos depósitos associados ao Vulcao das Furnas, imponente centro traquftico situado na zona leste da ilha de Sao Miguel, encontra-se bern definida para os tiltimos 5000 anos. Neste período registaram-se dez erupções, a mais recente das quais teve lugar em 1630. Até à data, esta última tem sido considerada a única erupcao histó...