Currently, the sheet-intrusion paths and geometries, including the sheet opening/thickness as well as the depth to sheet tip, are commonly determined from geodetic surface data using elastic dislocation models. These models assume the volcanic zone/volcano to be an elastic half space of uniform mechanical properties. Field observations, however, show that volcanic zones/volcanoes are composed of numerous

The catastrophic explosion of Mount Lamington volcano, Papua New Guinea on January 21, 1951 produced a devastating pyroclastic density current (PDC) that knocked down dense tropical rainforest over an area of 230 km2 and killed approximately 3000 people. We present results of a field reinvestigation of the 1951 PDC deposit combined with an analysis of the available photographs and eyewitness accounts

The ascent and extrusion of crystal-rich magma is commonly facilitated by deformation partitioned within annular, conduit-parallel shear zones. The physical properties and textures of the shear zone materials, where exposed at surface, provide a record of ascent and eruption dynamics. We describe the shear zone developed in Dome C, part of Chaos Crags in the Lassen Volcanic Center (California, USA)

Dilute pyroclastic density currents (dilute PDCs) are frequent and highly dangerous flows of hot gas and particles occurring at explosive volcanoes. The study and interpretation of the sedimentary characteristics of their associated deposits is one of the most important approaches to better understand these violent phenomena and to characterise their dynamics, frequency and magnitude in the geological

Estimates of the rheological properties of lava flows are essential for understanding their emplacement and for hazard assessment. Despite being a well-known phenomenon in water hydraulics, the formation and presence of standing waves in lava channels is poorly understood. Standing waves, generally located near the vent area, have been frequently described at high speed channelized lava flows. They

The alteration of soft volcanic rocks (i.e., characterized by a low uniaxial compressive strength <35 MPa) can change their permeability and mechanical strength. We built an alteration indicator based on porosity and cation exchange capacity (CEC) to connect the degree of alteration of soft volcanic rocks to their permeability and uniaxial compressive strength. The proposed empirical petrophysical

Mt. Tongariro is a multi-vent volcanic complex in the central North Island of New Zealand, constructed along the axis of an active graben. Its five largest-known explosive eruption episodes occurred 11,000 years ago during a ~200 year-long paroxysm. During these, stable Plinian and collapsing sub-Plinian columns erupted from multiple sequential and synchronous vents along the graben axis. We examined

Aragats stratovolcano, located on the South Armenian block, a micro-plate in the Arabian-Eurasian collision zone, has a complex and long-lasting Quaternary eruption history. Cataclysmic eruptions formed widespread pyroclastic deposits, which are interrupted by numerous basaltic to trachytic lava flows as well as lacustrine and lacustrine-alluvial sediments. Contrary to previous concepts, detailed mapping

The evolution of the petrophysical properties of rocks induced by hydrothermal alteration is often considered qualitatively by sorting the hydrothermal alterations encountered from low to high intensity, depending on the identified mineral paragenesis. In this paper, we studied the evolution of three different petrophysical properties (connected porosity, permeability and electrical conductivity) as

The timing and processes that govern the end of volcanic eruptions are not yet fully understood, and there currently exists no systematic definition for the end of a volcanic eruption. Currently, end of eruption is established either by generic criteria (typically 90 days after the end of visual signals of eruption) or criteria specific to a given volcano. We explore the application of supervised machine

Mineral phenocrysts/megacrysts convey important information about deep magmatic evolution and volcanic eruption especially with respect to magmatic water content. Clinopyroxene (cpx) is generally considered to be less susceptible to diffusive hydrogen loss than olivine and orthopyroxene. We analyzed hydrogen concentration profiles alongside major and trace element compositions of a suite of cpx megacrysts

The timing of the Holocene volcanic activity of Tenerife (Canary Islands) is poorly constrained and the volcanological framework for this area is still incomplete. Most of the eruptions are dated only by a single 14C dating, or the ages are simply stratigraphically determined. We apply palaeomagnetism, increasingly used in the last years to date Holocene volcanism, to improve the knowledge of Tenerife

Metals are efficiently transported in a gas phase and the gas composition strongly affects transport rates of these metals in the gas phase. Here we present a new approach to systematically investigate metal transport and deposition from volcanic gases of different compositions: We test the effect of sulfur and chlorine on the volatilization of 30 metal oxides and the phases deposited along a temperature

Since 2006, the Lusi mud eruption is ongoing in the northeast of Java Island, Indonesia. We perform a 3D seismic tomography of the area surrounding Lusi and the adjacent Arjuno-Welirang volcanic complex using P-wave arrivals of 797 local earthquakes recorded on 31 seismic stations for two years between 2015 and 2016. Resolution tests show that we can reasonably well constrain the subsurface velocity

We report on the Strombolian to Violent Strombolian eruption of Montaña Grande which occurred between 789 and 725 BCE in the Güimar Valley on the NE flank of Tenerife island. The eruption produced a ca. 180 m-high scoria cone, a thick fallout deposit mostly dispersed southwest and a vast lava flow field that extends east of the cone, towards the coast, for 3.3 × 2.2 km. The eruption occurred in an

The Snæfellsnes Peninsula of western Iceland is a region of transitional to alkaline Quaternary (<1.5 Ma) intraplate magmatism. Vatnafell, a sub-glacial tuya (~410 ka), is centrally located within the peninsula, between the Helgrindur/Lýsuskarð and Ljósufjöll volcanic systems, ~120 km from the divergent Western Volcanic Zone plate boundary. The Vatnafell edifice comprises a basal hyaloclastite unit

Mexico is the world's sixth-largest geothermal energy producer. To pursue its transition to renewable energy, other potential geothermal areas are under exploration. The Tacaná hydrothermal system is one of them. In this work, we developed a preliminary 2D numerical mass and heat flow model of the natural state of the Tacaná volcano in order to gain insight into fluid and rock properties at depth.

Through a detailed structural assessment of faults, carried out by remote sensing and a slip-dilation tendency analysis along with water geochemistry of thermal waters, it was possible to characterize the geothermal system of Cerro Machin Volcano (CMV) located in the western flank of the Cordillera Central of Colombia. The study shows that the geothermal system presents a favorable structural setting

Preferential fluid pathways along regional fault systems are crucial for the spatial localization of volcanic and geothermal manifestations. Differences in electric properties of fluids and hydrothermal alteration products against the unaltered matrix allow for visualization of such pathways. Unfavorable geometry for 2-D inversion resulting from the fluid pathways in regional faults often being aligned

A geochemical study was carried out at Fogo Lake during June 2016, in one of the deepest lakes on São Miguel Island, as well as on small associated pond, in order to identify possible anomalous degassing areas. Fogo Lake is located inside the summit caldera of Fogo Volcano, one of the three active central volcanoes that dominate São Miguel geology. The hydrogeochemical profile carried out along the

Combined interpretation of Electrical Resistivity Tomography (ERT) data, with plume and fumarolic gas emissions provides a snapshot of the Whakaari/White Island hydrothermal system 11 months prior to an eruption on December 9, 2019. Two and three dimensional inversion of the ERT data images the F0 fumarole as a low resistivity (2–5 Ωm) feature reflecting the two-phase zone surrounding the single phase

Stress fields in the Earth's crust are important indicators leading to better understanding of geologic processes. One way to acquire stress data is through morphometric analysis of volcanoes. Here we evaluate 141 Quaternary-age monogenetic and polygenetic volcanoes and volcanic fields in Java, Indonesia, using a 30-m SRTM DEM, an 8-m DEMNAS, aerial photos, published geological maps, and Landsat and

One of the most challenging tasks in volcanic data analysis is the classification of seismic events. By knowing them, it is possible to take decisions in advance, providing benefits for the neighboring societies as, for instance, how such events may impact users' life and cropland areas. Although there are several approaches to perform such task, Deep Neural Networks (DNN) have been barely considered

One of the best known places on Earth where volcanology meets archaeology and history is the volcanic island of Santorini (Thíra), Greece. It is famous for the cataclysmic Late Bronze Age (Minoan) Plinian eruption which destroyed the Minoan culture that flourished on the island. Hosting a central, flooded caldera bay and, within that, the active islands of Palaea and Nea Kameni, Santorini volcano has

Anticipating volcanic eruptions at central volcanoes require knowing how magma chambers prepare for new eruptions. Pre-eruptive processes that occur in such magma chambers are recorded in the products of these eruptions, so their characterisation in terms of magma composition and physics offers the clues to understand past eruptions and predict future ones. Here, we study the very well preserved pyroclastic

The Ring of Fire represents a constant threat in the case of possible eruptions due to its 160 active volcanoes. Consequently, several studies have determined that an increase of tectonic and long period events could indicate the beginning of a volcanic eruptive process. In this context, it is crucial to improve microearthquake detection by using real-time automatic recognition systems. For this purpose

The Clear Lake Volcanic Field in northern California is the youngest and northern-most part of a long-lived volcanic system that has produced recent (∼10 ka) eruptions. Adjacent to the Clear Lake Volcanic Field is the world's largest energy producing geothermal field, The Geysers. The hottest part of The Geyser's geothermal field is in the northwest where temperatures reach ∼400 °C at 3 km depth. Low

Volcanic unrest during 2002–2006 renewed attention on Changbaishan-Tianchi volcano as the source of the powerful explosive eruption (VEI 6 to 7) Millennium Eruption of 946 CE (Common Era). However, progress in understanding the potential risk is complicated by discordant accounts of the most recent, explosive eruptive history. Several eruptions since the Late Pleistocene, such as the Tianwenfeng (TWF)

The lake waters of Kawah Ijen volcano are concentrated hyperacidic brines that obtain their composition from volcanic gases and water-rock interaction. Lake water and hydrothermal fluids seep through the western flank of the volcano where they precipitate gypsum and form the hyperacid Banyu Pahit river. In this contribution, we present compositional data from bi-weekly samples taken from the Banyu

Most arc volcanoes erupt intermediate to silicic magmas that have sufficient volatile contents to behave explosively. Despite this explosive potential, low-energy effusive eruptions of such viscous water-rich magmas are common occurrences. Hence, predicting the style of the next eruption, with its obvious importance on hazard mitigation, remains one of the main challenges of volcanology. Here, we investigate

This paper examines the human-nature dynamics of volcanic eruptions through a multidisciplinary exploration of the recently-formed Hunga Tonga Hunga Ha‘apai (HTHH) landmass in the Kingdom of Tonga. HTHH was formed in early 2015 in the Ha‘apai island group in southwestern Tonga. This landmass has persisted longer than expected, providing a rare opportunity to examine pathways of erosion and biological

Evidence of metal transport by volcanic gases is found, amongst others, in volcanic plumes and sublimates growing around fumaroles. The transport mechanisms (i.e. volatile metal compounds) are, however, not well constrained. Here, we present results on the volatile transport of metals at the scale of a magmatic-hydrothermal system, White Island volcano. We studied metal emissions from the main vent

Open vent basaltic volcanoes account for a substantial portion of the global atmospheric outgassing flux, largely through passive degassing and mild explosive activity. We present volcanic gas flux and composition data from Yasur Volcano, Vanuatu collected in July 2018. The average volcanic plume chemistry is characterised by a mean molar CO2/SO2 ratio of 2.14, H2O/SO2 of 148 and SO2/HCl of 1.02. The

The thermal properties of volcanic rocks are crucial to accurately model heat transfer in volcanoes and in geothermal systems located within volcanic deposits. Here we provide laboratory measurements of thermal conductivity and thermal diffusivity for variably porous andesites from Mt. Ruapehu (New Zealand) and variably altered basaltic-andesites from Merapi volcano (Indonesia) measured at ambient

Hot springs and related deposits are common features in active geothermal areas around the world. In this study, centered on the Ixtlán de los Hervores geothermal zone (Michoacán, Mexico), we analyzed the distribution of active hydrothermal manifestations and hot-spring deposits as well as the local stratigraphy to determine the influence of the faults in the hydrothermal fluid circulation. The hydrothermal

We analyze the age distribution provided by 113 sanidine crystals separated from six samples of pyroclastic products of the Bolsena-Orvieto phase of activity at the Vulsini Volcanic District, which were dated via the 40Ar/39Ar single crystal, total fusion method in a previous study. Moreover, we investigate the compositional and depositional features of the dated products, both at the outcrop scale

Long Valley Caldera has been restless since at least 1978. Prominent symptoms of this unrest include earthquake swarms and tumescence (inflation) centered on the resurgent dome. Over the years, interpretations of physical processes underlying this unrest have varied considerably. Results from a collection of geophysical studies infer the presence and/or active intrusion of magma in the crust. Geologic

The Kuju volcano group in the southwestern part of the Oita prefecture, Japan, consists of more than 20 volcanoes distributed over an area of approximately 400 sq. km. On October 11, 1995, a phreatic eruption occurred on the eastern flank of Mt. Hossho, in the central part of the Kuju volcano. A second eruption occurred in mid-December 1995, producing an ash volume of approximately 5000 m3. Therefore

Long-term eruptive activity at the Santiaguito lava dome complex, Guatemala, is characterised by the regular occurrence of small-to-moderate size explosions from the active Caliente dome. Between November 2014 and December 2018, we deployed a seismo-acoustic network at the volcano, which recorded several changes in the style of eruption, including a period of elevated explosive activity in 2016. Here

Boron is a potentially toxic element in the environment and commonly enriched in high-temperature geothermal waters. In this study, seven typical boron-rich geothermal areas in Tibet (China) were selected as the study areas for comprehensively investigating the geochemistry of geothermal boron and its environmental impact. The geothermal waters were classified into four types: acid low-boron waters

Tephra layers are frequently used to reconstruct past volcanic activity. Inferences made from tephra layers rely on the assumption that the preserved tephra layer is representative of the initial deposit. However, a great deal can happen to tephra after it is deposited; thus, tephra layer taphonomy is a crucial but poorly understood process. The overall goal of this research was to gain greater insight

Volcanic gas sampling and SO2 flux measurements were performed on Taftan volcano (3920 m height, SE Iran, Makran volcanic arc) and Damavand volcano (5610 m height, Northern Iran, Alborz Mountains). Both volcanoes possess near-summit fumarolic fields with moderately intensive gas jets and temperatures up to 160 °C (Taftan) and 175 °C (Damavand). Gases of both volcanoes contain (mmol/mol): H2O (910–930)

The Late Bronze Age (LBA) eruption (ca. 1650 BCE) of Thera (Santorini) was one of the largest known in history, burying and destroying a thriving Theran (Cycladian) culture that occupied the island and surrounding islands. The consequent thick tephra deposit provides detailed information on the eruptive sequence and vent mechanics – it also provides details on that culture through burial of towns,

The syneruptive decompression rate of basaltic magma in volcanic conduits is thought to be a critical control on eruptive vigor. Recent efforts have constrained decompression rates using models of diffusive water loss from melt embayments, olivine-hosted melt inclusions and clinopyroxene phenocrysts; however, these techniques are difficult to apply because of the rarity of pyroxene crystals or melt

The dichotomy between probabilistic and scenario-based volcanic hazard assessments stems from their opposing strengths and weaknesses. The quantification of uncertainty and lack of bias in the former is balanced against the temporal narrative and communicability of the latter. In this paper we propose a novel methodology to bridge between the two, deriving a pseudo-probabilistic hazard estimate from

Amphibole phenocrysts and crystal clots composed of amphibole, plagioclase, and interstitial glass were observed in dacitic products of the Unzen 1991–1995 eruption and analyzed in order to understand pre-eruptive magmatic processes. Amphibole phenocrysts in the samples erupted at different times are classified by composition as either magnesiohornblendes or tschermakites. Temperatures of 770–830 °C

We report here on the first focused study of gas discharges and thermal spring waters at Okmok volcano since the 2008 phreatomagmatic eruptions. Results include the first compositional gas data from Okmok with minimal air contamination and the first data on magmatic carbon in Okmok spring waters. Chemical and isotopic analyses of the waters and gases are used to assess the character of Okmok fluids

The Campania region of southern Italy, dominated by Mount Vesuvius, is an enduring volcanic landscape which hosts a wealth of detailed information about human responses to past eruptions. This research taps into rich archaeological, geological, and historical data to bring together the past, present and future of Mount Vesuvius and the populations surrounding it. Records from the Avellino eruption

Glaciovolcanism produces distinctive features that are useful paleoclimate proxies for the distribution of past ice sheets and glacier extent. The Copahue volcano located in the Andean Southern Volcanic Zone, Argentina-Chile, is an active composite volcano known to have glaciovolcanic features such as lava bodies with glassy margins and anomalous cooling fractures. However, the emplacement conditions

In this work, we present the development, description, and performance evaluation of two volcano seismological datasets: one containing raw seismic signals (MicSigV1) and another containing a set of 84 distinctive attributes or features for bench-marking (SeisBenchV1), which was extracted from the MicSigV1 dataset, recorded at Cotopaxi volcano in Ecuador. These datasets represent the first public Ecuadorian

During a volcanic unrest period with magma-chamber rupture, fluid-driven fractures (dykes) are injected either from deep reservoirs or shallow magma chambers. Subsequently, the dykes follow propagation paths towards the surface, some eventually reaching the surface to erupt while others become arrested. Here we study dyke paths resulting in eruption or arrest in an excellent 5-km wide exposure of the

The Yadong–Gulu rift (YGR) is famous for its extensional structure in the compressional background of Tibet. The mid-crust of the rift is partially molten, which has attracted considerable attention regarding whether it is associated with the regional tectonics and hydrothermal system. The Cs contents of the travertines of the YGR have attained the standard of “Chinese pay grade” (Cs2O: 100 ppm), however

Surface deformation of volcanic areas can reveal information about subsurface magma reservoirs and how magma is transported between them, which is an important part of volcano monitoring for hazard mitigation. One prominent style of deformation observed at Kīlauea volcano, Hawai'i, is episodic deflation-inflation (DI) events, which are recorded in surface deformation data and characterized by deflation

Phreatic activity of Merapi started after nearly 2 years of quiescence following the October–November 2010 eruption which was the largest in more than 100 years. A dozen eruptions identified by visual and/or seismic observations took place between August 2012 and April 2014. We present in this work the results of a detailed analysis of the April 20, 2014 phreatic eruption. We attempted to reconstruct

The Rhine River (Germany) - the largest river in Western Europe - was dammed by pyroclastic material multiple times during the major Plinian Laacher See Eruption (12,900 BP). Dams formed both upstream and downstream of the broad tectonic Lower Neuwied Basin (LNB) which interrupts the narrow Rhine canyon. Here we document upstream damming of the Rhine River at the entrance to the LNB close to the present

Understanding lava dome eruptions is a major concern in volcanology regarding the assessment of associated hazards. This question is usually addressed through the study of active calc-alkaline domes, however, alkaline domes remaining poorly known. The Puy de Dôme is the most prominent volcano of the Chaîne des Puys Quaternary intraplate volcanic field in the French Massif Central. It is a complex trachytic

In the Amiata volcanic–geothermal area, natural soil degassing of CO2 is particularly intense and observed over a wide area, including the volcano complex and its surroundings. A survey systematically and directly measured the natural total soil CO2 flux over the whole area, comprising 2482 measurements over an area approximately 225 km2. Sequential Gaussian simulations generated CO2 flux maps for

Mercury (Hg) is a widely spread pollutant, owing to its high mobility in the nature. The rising input of Hg into the atmosphere has resulted in enhanced Hg pollution in both terrestrial and aquatic ecosystems. The Tibetan plateau, which is known as the roof of the world, is considered as Hg-sensitive ecosystems. The Himalayan-Tibetan geothermal belt, which is formed due to the collision between India

This study presents a photogrammetric method for 3D reconstruction of a volcanic plume outline to retrieve its spatial properties. A dataset of sequential multi-view images was collected, using a drone-mounted camera, for a small-scale volcanic plume emitted from Volcán Pacaya, Guatemala. A ‘Space Carving’ algorithm has been applied to estimate the plume shape, top height, volume and drift direction