The Lost Jim flow field, in the Imuruk Lake volcanic field, Alaska, extends west ~34 km from a single vent, crossing subarctic tundra and currently touches several lakes and streams. The weighted mean of five 36Cl cosmogenic exposure ages from the Lost Jim pāhoehoe flow is 7.73 ± 0.37 ka, indicating this eruption occurred substantially after the eruption of the underlying Camille flow, which was emplaced at 39.7 ± 1.3 ka. Paleoclimate records indicate the period when the Lost Jim flow field was emplaced was after deglaciation, and the climate was similar to today. We propose that the emplacement of lava in these cold subarctic conditions can lead to faster cooling of the lava surface compared to lava emplaced in warmer locations such as mid- latitude cold deserts. Glass abundance in the outermost rinds at the Lost Jim flow field was on average 74 % with 6.4 mm thick rims, compared to 60 % with 2.9 mm rims for cold mid-latitude desert samples. We interpret increased glass content as a proxy for rapid cooling likely occurring partly during winter. Glassiness values varied less across vent, margin, and mid-flow locations when compared to the mid-latitude flows suggesting the Lost Jim flow field was broadly impacted by the subarctic climate as opposed to responding to local microclimates. Our results indicate that lava glassiness may be a useful environmental indicator of cooler (in this case subarctic) conditions.
The sequence of six paroxysmal eruptions that occurred between July and August 2024 at Mt. Etna’s Voragine crater has been investigated in order to constrain the plumbing system dynamics. Whole-rock and glass major-element analyses have been integrated with a detailed petrological study of erupted products, focusing on olivine major-element compositions to track magma storage and transfer dynamics leading to the eruptions. Olivine chemistry and thermodynamic modeling indicate an intermediate reservoir at ∼2.7 km b.s.l. as the main magma storage region. Fe–Mg diffusion chronometry on zoned olivines constrains magma transfer timescales, suggesting mafic recharge from depths of 6–8 km b.s.l. over 3—4 months, followed by progressive replacement of magmas occupying the shallower levels 1—3 weeks before the onset of Strombolian activity in mid-June. Compared to the last lava fountain activity at Voragine in 2015–2016 and the long-lasting sequence at South East Crater in 2020—2022, the 2024 magmas underwent slower transfer from depth and longer residence at intermediate storage levels, suggesting important modifications in the working modes of the current plumbing system.
Pit craters are observed throughout the solar system, but are rarely seen forming. Here we document pit crater formation and characteristics following the 2011–2012 Cordón Caulle rhyolitic eruption using satellite and drone data with field observations. Syn-eruptive shallow intrusion (laccolith) uplift and subsequent subsidence at Cordón Caulle are found to be responsible for the creation of faults and fractures as well as at least 349 collapse pits. At Puyehue volcano, we measure nearly 35 m of subsidence within the 2.5 km wide summit caldera from 2016–2024 using digital elevation models leading to ring fractures and pit craters forming inside the caldera. Some pit craters may form from melting snow buried by tephra deposited during 2011–2012. This study offers a unique example of near real-time pit crater formation and evolution, which may be applied to better understanding these processes on Earth and other planetary bodies.
Pyroclastic density currents (PDCs) are among the most lethal volcanic phenomena and are mainly generated by column collapse, lateral blasts, or dome failure. An additional but still poorly constrained hazard is represented by PDCs produced by the collapse of hot volcaniclastic deposits. Here we investigate deposit-derived (dd) PDCs emplaced during the 1944 eruption of Vesuvius (Italy). We integrate historical literature, contemporary written and photographic sources, and new field observations with a reconstruction of the pre-eruptive topography based on vintage aerial photographs and digital elevation models. Our results show that the pre-eruptive crater geometry exerted a primary control on deposit accumulation, failure mechanisms, and runout behaviour. Volume–area relationships indicate that failure mechanisms broadly consistent with translational, near-planar collapse. Individual dd-PDCs reached volumes of up to ~3×106 m3 and runout distances of ~1–1.5 km, ranking among the largest PDCs associated with sustained lava fountaining and highlighting an underestimated hazard capable of affecting areas up to 2 km from the vent.
Following the 2018–2020 Fani Maoré submarine eruption near Mayotte Island, Indian Ocean, multiple oceanographic expeditions provide unprecedented access to fresh alkaline volcanic glasses spanning basanite to phonolite compositions from the East-Mayotte Volcanic Chain (EMVC). We applied Fe and S K-edge X-ray Absorption Near-Edge Spectroscopy (XANES) to determine iron and sulfur oxidation states in 13 glass samples, providing the first comprehensive redox characterization of this submarine volcanic system. Fe3+/FeTOT ratios range from 0.19 to 0.51, while S6+/STOT ratios span 0.02–0.17, with more evolved compositions that tend to show higher oxidation states. Beam damage monitoring revealed significant photo-oxidation effects on sulfur measurements, requiring analysis of initial spectra only. Comparison of redox estimates from multiple independent oxybarometers based on the Fe3+/FeTOT and S6+/STOT as well as the olivine-spinel-ameltSiO2 reveals systematic discrepancies between Fe-based and S-based estimates, likely due to Fe-Ti nanolite contamination along X-ray beam paths. Integration of S6+/STOT measurements with the olivine-spinel-ameltSiO2 oxybarometer indicates ΔFMQ = +0.3 ± 0.2 for basanite to tephriphonolite magmas, suggesting slightly more oxidized conditions than previously estimated for EMVC. These results provide essential constraints for thermodynamic modeling of alkaline submarine volcanism and highlight the importance of multi-proxy approaches in determining magmatic redox conditions. The oxidation state is consistent with other regional volcanic systems in the SW Indian Ocean, supporting a moderately oxidized mantle source beneath the Comoros archipelago.
Volcanic eruptions can cause substantial damage and disruption to infrastructure and communities. Contemporary societies typically depend on petroleum infrastructure. Volcanic unrest and eruptions can cause considerable operational and structural challenges for the petroleum sector. The vulnerability of this sector to volcanic hazards is understudied when compared to other potentially dangerous phenomena (e.g. earthquakes). In this paper, we present new volcanic physical vulnerability models for the four key asset classes of the petroleum sector: wells, pipelines, production facilities and storage tanks. The vulnerability models are developed based on a literature review and facilitated expert judgement in the form of workshops with petroleum engineers and volcanic risk experts. These models consider four hazard intensity metrics (burial thickness, static load, dynamic pressure and airborne ash concentration) and are thus applicable to multiple volcanic hazards. We apply these models to pre-existing multi-hazard eruption scenarios for Taranaki Mounga volcano in Aotearoa New Zealand, using an available impact assessment framework to demonstrate their usability in impact and risk modelling. Our impact assessment indicates that a future eruption of Taranaki Mounga volcano could cause widespread impacts to the petroleum sector, which would in turn create a prolonged national emergency due to energy supply shortages for major industries and consumers. These vulnerability models may be applied in other volcanic regions worldwide to inform risk reduction and readiness actions.
The August 2021 eruption of Fukutoku-Oka-no-Ba (FOB) volcano in Japan was a remarkable VEI 4 shallow submarine eruption, partly because it generated a 16-km water-rich atmospheric plume, new islands, and a large pumice raft. Recent studies provide complementary summaries of the atmospheric and oceanic surface expressions of the 2021 FOB eruption, including analyses of regional infrasound and Himawari-8 geostationary satellite data. The hydroacoustic record has also been published. Following these studies, we examine how the processes occurring beneath the sea surface correlate with the intensity of the atmospheric portion of the 2021 FOB eruption. We compare multiple data sets, specifically International Monitoring System hydroacoustic and infrasonic array data in the context of ground-based lightning observations, and plume height and width data (Himawari-8). We estimate a time-varying volumetric flow rate from plume observations and compare the resulting time series with acoustic and lightning characteristics. The infrasound data do not correlate with the other data streams due to signal loss from diurnal winds. The lightning, hydroacoustic, and volume-flux data are highly correlated, and we suggest this is because all three depend on eruption flux and intensity at the vent.
Despite involving no fresh magma, phreatic eruptions are increasingly found to contain juvenile material. This study seeks to determine whether the glass is the result of an input of new magma or shallow stalled magma passively entrained. Using hydrogen isotope analysis (δD) and water speciation (OH/H2Omol), we differentiate between fresh magmatic and rehydrated glasses. At Rincón de la Vieja, glasses exhibit H2Ototal contents up to 0.71 wt.% and δD values between –27‰ and –3‰, indicative of secondary hydration by a single hydrothermal source. In contrast, Turrialba samples show a mixed signal; six samples fall within magmatic δD and water content values, while three exhibit δD values from –99‰ to –104‰ and elevated H2O contents up to 2.29 wt.%, consistent with secondary hydration by local meteoric waters. Rehydration by hydrothermal fluids supports the conclusion that magma was stored at a shallow level and could be entrained during purely phreatic eruptions.
Despite extensive contemporary documentation of the 1963–1965 Irazú eruption, a detailed analysis of its proximal tephra deposits has been lacking. Here, we characterize the stratigraphy and sedimentology of these deposits, interpret their depositional processes including tephra recycling, and constrain magma recharge timing through geochemical data. The eruption was predominantly phreatomagmatic, with subordinate Strombolian and rare phreatic events, producing ~6.2 × 107 m3 of tephra (DRE: 5.68 × 107 m3; VEI 3). Four eruptive stages were identified by correlating deposits with contemporary observations. The irregular pre-1963 crater morphology controlled the development of an asymmetrical tuff cone and a maar-like crater. Intra-crater deposits (~28 m) and rim deposits (~5.7 m) include fallout beds, ballistic curtain deposits, dilute pyroclastic density currents, and massive ash beds. The steep, funnel-shaped crater promoted significant tephra fallback and recycling, and confinement of pyroclastic flow deposits. The deposits record compositional enrichment in incompatible elements from June 1964 indicating magma recharge, while mineral zoning patterns show evidence of magma mixing. These results demonstrate that moderate-intensity summit eruptions can exhibit complexities typically associated with maar-diatreme systems.
Traditional Knowledge and oral accounts of natural phenomena provide valuable insights into natural hazards, including volcanic eruptions. Indigenous societies with Oral Traditions have often developed culturally grounded strategies for mitigating volcanic hazards. However, the integration of cultural knowledge and scientific understanding remains underexplored in modern volcanic hazard mitigation. This study takes a qualitative approach, using examples from Australasia and the Pacific Islands, to examine how the integration of long-standing cultural knowledge and volcanological research can enhance our understanding of precursory activity, eruption chronologies, and the relative timing of past volcanic events. Additionally, it offers detailed accounts of the hazards experienced and their impacts on people and the environment. We also propose directions for future research. Whilst differing world views in the causation of volcanic activity will remain, incorporating all available knowledge on past volcanic events will help local communities in volcanically active regions become better prepared and more resilient to future volcanic activity.
Continuous monitoring of volcanoes is essential for advancing scientific understanding and issuing alerts to at-risk populations. Many volcanoes are equipped with ground-based RGB cameras, whose recordings are analyzed by experts or semi-automatic models. Automatically distinguishing clouds from volcanic columns and other emissions remains a major challenge. To date, no open-source labeled database of volcanic images exists, and no study has attempted to localize multiple emissions beyond ash columns. We introduce VIGIA-PlumeNet, capable of operating across diverse environments a,nd sky conditions. It performs multi-class segmentation, identifying the volcano and distinguishing plumes, gases, and lava, with 88 % accuracy on the 58 test images when excluding the background class. This is achieved by using the versatile DINO-v2 AI model as a general visual processor, paired with a specialized component that we specifically trained to pinpoint and outline volcanic features; and constructing VIGIA-PlumeData, a dataset of 250 manually annotated images from over 60 volcanoes worldwide, collected through community effort. VIGIA-PlumeData and VIGIA-PlumeNet are released publicly, establishing the first benchmark dataset for volcanic image segmentation.
Volcanic plumes are important because they spread volcanic material, can impact climate, and pose hazards to aviation. Among eruption processes, column collapse is arguably the most consequential in terms of direct impacts, as it marks the onset of ground-hugging pyroclastic density currents that pose the greatest immediate threat to life and infrastructure. This study investigates how external water, such as is incorporated during subaqueous eruptions, affects the critical condition (including mass eruption rate, temperature, and gas fraction) at which column collapse occurs in the atmosphere, referred to as "the column collapse condition". We use the 1-D plume model, Plumeria, to explore how variations in external water (0-60 wt.degrees%o), vent exit velocity (75-125 m s(-1)), and initial magma temperature (700-1100 degrees C) affect the column collapse condition. We find that the occurrence of column collapse is highly sensitive to the amount of external water. Small amounts of external water ((sic) 25 wt.degrees%o) suppress column collapse, whereas higher amounts of water encourage collapse. Using more than 150,000 simulations, we map out the highly non-linear shape of the column collapse condition as a function of mass eruption rates and external water contents. The Richardson number, the ratio of buoyancy to shear forces, offers a useful framework for defining the column collapse condition for eruptions involving external water. This work enhances our understanding of how external water ingestion affects volcanic plume dynamics, including height and column collapse conditions. Recent shallow submarine eruptions that produced very tall atmospheric plumes and partial column collapse (e.g. the 2021 Fukutoku-Oka-no-Ba eruption in Japan and the 2022 Hunga eruption in Tonga) demonstrate the importance of understanding how external water influences the collapse of eruption columns.
The VEI 4 eruption of La Soufrière Volcano underwent a dramatic transition in style from initial lava dome effusion in December 2020 to hazardous explosive activity in April 2021. Understanding the magmatic processes underpinning such transitions is critical. We provide the first comprehensive dataset of the compositions and volatile contents of melt inclusions from the 2021 explosive activity, including the first measurements of pre-eruptive total CO2 at La Soufrière and estimates of magmatic temperature. We use the petrological method to quantify volatile fluxes to the atmosphere of 5.40 ± 0.60 Mt H2O, 0.37 ± 0.04 Mt CO2, 0.13 ± 0.01 Mt SO2, and 0.33 ± 0.04 Mt HCl. Modelling of volatile saturation pressures indicates final magma storage depths of 2.4–8.9 km (mean 6.4 km) throughout four phases of explosive activity after migration of magma in the lower storage region within the transcrustal mush system. Inferred depths are consistent with recorded seismicity and deformation before and during the explosions.
Classroom demonstrations of volcanic processes are typically performed with low-temperature materials designed to exhibit behaviors conceptually analogous to magma. However, there are advantages to finding methods by which real magma can be created and used with audiences and students. Here, we describe a method by which magma can be made at home or in a classroom using a standard household microwave. We have tested a particular demonstration of how volatiles such as H2O exsolve from natural obsidian to form pumice and ash, a direct replica of the volcanic phenomenon that drives eruptions on Earth and other planets. To demonstrate this, we used three obsidian samples—from Mono Craters (U.S.A.), Arteni (Armenia), and Hrafntinnuhryggur (Iceland)—within an off-the-shelf ceramics "microwave kiln" in both a 700 and 1000 W microwave. We found that millimetric obsidian chips will vesiculate to form pumice-like textures at low microwave power or low initial H2O content and will fragment safely within the kiln at high microwave power or high initial H2O content. This can be used to supplement existing well-known demonstrations using low-temperature analogs for magma. The demonstration results in real "products" that can be examined just as a geologist would examine natural specimens.
Paroxysmal mafic activity is a relevant source of hazard at many active volcanoes. At volcanoes like Etna (Italy), paroxysmal eruptions have highly variable transient dynamics, thus monitoring activities are crucial for the understanding and quantification of the onset of climactic phases. We examined thermal videos from the INGV-OE (Istituto Nazionale di Geofisica e Vulcanologia – Osservatorio Etneo) monitoring network of seven lava fountains that occurred at the South-East Crater in 2021. We identified the processes that precede and lead to the onset of the fountaining phase to implement a thermal analysis tool that can be used, in conjunction with radar data, to fully characterize the dynamics and duration of paroxysmal events. Based on the signal derived by our parameter, we recognized different phases (strombolian; waxing; waning) preceding and following the climax of the paroxysms. Our method, if linked with other monitoring data, could also be easily implemented in early warning systems.
The eruptive style of magma is shaped by both storage conditions and ascent processes. Peralkaline melts, with relatively high water concentrations and low viscosity, are expected to better resist magmatic fragmentation compared to peraluminous melts. However, trachytic and phonolitic magmas can still generate highly explosive eruptions, as demonstrated by the Rungwe Pumice Plinian eruption (Tanzania). This VEI 5 event involved a crystal-poor, microlite-free phonolitic/trachytic magma stored at high temperatures and relatively low water concentrations. 2D and 3D textural analyses, coupled with embayment speedometry, reveal a delayed homogeneous bubble nucleation event (ΔPsat ~50 MPa) at shallow depths. Rapid bubble nucleation and growth during fast ascent (~6 MPa·s⁻¹) prevented the formation of a highly vesicular foam and consequently, low permeability restricted outgassing. Strong melt-gas coupling, combined with a sudden rheological shift, ultimately led to fragmentation. This eruption underscores the critical role of conduit dynamics in peralkaline magma explosivity, beyond storage conditions alone.
Volcanic plumes are important because they spread volcanic material, can impact climate, and pose hazards to aviation. Among eruption processes, column collapse is arguably the most consequential in terms of direct impacts, as it marks the onset of ground-hugging pyroclastic density currents that pose the greatest immediate threat to life and infrastructure. This study inves- tigates how external water, such as is incorporated during subaqueous eruptions, affects the critical condition (including mass eruption rate, temperature, and gas fraction) at which column collapse occurs in the atmosphere, referred to as “the column collapse condition”. We use the 1-D plume model, Plumeria, to explore how variations in external water (0–60 wt.%), vent exit velocity (75–125 m s−1), and initial magma temperature (700–1100 °C) affect the column collapse condition. We find that the occurrence of column collapse is highly sensitive to the amount of external water. Small amounts of external water (⪅ 25 wt.%) suppress column collapse, whereas higher amounts of water encourage collapse. Using more than 150,000 simulations, we map out the highly non-linear shape of the column collapse condition as a function of mass eruption rates and external water contents. The Richardson number, the ratio of buoyancy to shear forces, offers a useful framework for defining the column collapse condition for eruptions involving external water. This work enhances our understanding of how external water ingestion affects volcanic plume dynamics, including height and column collapse conditions. Recent shallow submarine eruptions that produced very tall atmospheric plumes and partial column collapse (e.g. the 2021 Fukutoku-Oka-no-Ba eruption in Japan and the 2022 Hunga eruption in Tonga) demonstrate the importance of understanding how external water influences the collapse of eruption columns.
Melt inclusions provide a critical archive of primary magmatic compositions, particularly for reconstructing volatile systematics that are otherwise obscured by syn-eruptive degassing. Accurate quantification of volatile species such as CO2 requires robust determination of both melt and vapour bubble volumes within polyphase inclusions. Conventional 2D optical measurements impose simplified geometries and assumptions, introducing significant and often unquantifiable errors. Here we demonstrate that X ray Computed Tomography (XCT), a non destructive, high resolution 3D imaging technique, provides substantially more accurate and reproducible melt inclusion and bubble volume measurements across a large dataset of olivine hosted inclusions. Comparison with traditional methods reveals that 2D approaches can overestimate bubble volumes by 14–40%, with errors expected to rise substantially in inclusions with complex morphology. XCT not only improves volumetric accuracy but also enables explicit uncertainty evaluation through repeat scanning and variable image processing. These advancements significantly enhance CO2 reconstructions and thereby refine estimates of magmatic volatile budgets, storage depths, and magmatic compositions.
Steady-state volcanoes and magmatic provinces erupt magmas at nearly constant rates over the course of decades. Here, we analyzed the reliability of steady-state volcanism and its relationship with volcanic hazard evaluation in terms of forecasting the erupted volume at four frequently erupting oceanic hotspots: Iceland, La R & eacute;union, Hawai'i, and western Gal & aacute;pagos. Over decadal timespans, these hotspots show steady-state activity often characterized by shorter-term cycles with an initial decrease in eruption rates, followed by an increase that rebalances the erupted volumes with the expected ones, providing a rough estimation of the maximum expected erupted volume of these paroxysmal periods. Although rarer, we also observe the opposite behaviour, with the eruption of more magma than expected, followed by low-rate periods proportional to the excess erupted volume. Steadystate rates can change over time, and future studies should investigate if these changes are related to longer-term episodes.
Stromboli is a unique open-conduit mafic volcano known for persistent Strombolian eruptions of highly porphyritic (HP) basalticshoshonite scoria. Stronger paroxysmal explosions occur once or twice per decade, ejecting low porphyritic (LP) golden pumice from deeper volatile-rich magma. The July 3rd, 2019, paroxysm showed features of a Vulcanian eruption—supersonic blast, ballistic ejection, and pyroclastic flows—despite Stromboli’s open-conduit basaltic nature. Textural analysis suggests that LP pyroclasts formed via rapid decompression, fragmentation, and quenching. This event likely resulted from shallow HP-filled conduit pressurization and failure triggered by a rising large gas slug. This caused top-down decompression, evacuating both HP and deeper LP magma. The proposed “basaltic Vulcanian” model better fits geophysical data than the traditional deep LP magma ascent model.
