Journal of Volcanology and Geothermal Research最新文献

{"title":"Subsurface mass monitoring at Theistareykir geothermal field, Iceland, using hybrid gravimetry","authors":"B. Giuliante ,&nbsp;U. Riccardi ,&nbsp;J. Hinderer ,&nbsp;P. Jousset ,&nbsp;T. Pivetta ,&nbsp;A.K. Mortensen ,&nbsp;J.D. Bernard ,&nbsp;S. Schröder ,&nbsp;C.M. Krawczyk","doi":"10.1016/j.jvolgeores.2026.108539","DOIUrl":"10.1016/j.jvolgeores.2026.108539","url":null,"abstract":"<div><div>Understanding underground mass redistribution in geothermal fields is fundamental to assess the harnessing in geothermal reservoir. Here we apply the hybrid gravimetry method at Theistareykir geothermal field (Northern Iceland). We collected absolute and discrete microgravity measurements yearly within the geothermal field at fixed locations jointly with continuously recorded gravity time series with two superconducting gravimeters (SGs). Data acquisition started in 2017 at the onset of the anthropogenic perturbation. We present and interpret the discrete and continuous gravity datasets from 2017 until 2024 in an attempt to characterize fluid redistribution within the subsurface. The hybrid gravimetry dataset reveal a gravity decrease nearby the extraction area with rates of about −20 μGal per year for the 2017–2022 period, that reduces to few μGal per year in the last two years (2023–2024). An increase in gravity is observed towards the injection area (around 5 to 10 μGal per year). Time-lapse gravity maps reveal a localized gravity decrease (with a maximum of −60 μGal), not collocated with the zone of largest extraction and furthermore an additional trendline of gravity increase (+15 μGal) is observed towards the North. The first suggests a possible lower permeability subsurface zone within the geothermal field, the latter, is in accordance with the direction of the fault system that crosses Theistareykir field, suggesting potential underground fluid pathways. From 2023, although extraction and injection rates did not change, we evidence a change in the gravity trends outside the western part of the geothermal field possibly associated with the 2023 magmatic intrusion.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"472 ","pages":"Article 108539"},"PeriodicalIF":2.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cracking the crust: Rifting and lateral magma transport at the early Holocene Sveinar-Randarhólar Fissure, NE Iceland","authors":"Adam Abersteiner ,&nbsp;Christoph Beier ,&nbsp;Sæmundur A. Halldórsson ,&nbsp;Edward W. Marshall ,&nbsp;Eemu Ranta ,&nbsp;Magnús Á. Sigurgeirsson ,&nbsp;Martin Whitehouse ,&nbsp;Heejin Jeon","doi":"10.1016/j.jvolgeores.2026.108557","DOIUrl":"10.1016/j.jvolgeores.2026.108557","url":null,"abstract":"<div><div>The ∼11 ka Sveinar-Randarhólar Fissure (SRF), located in the neovolcanic Northern Volcanic Rift Zone (NRZ; Central East Iceland), is a ∼ 75 km long, north-south trending fissure comprising of a discontinuous chain of scoria cones and basaltic lava flows distal to any central volcanoes. We report petrography, mineral-glass compositions, whole-rock major and trace elements, Pb-isotopes, and olivine O-isotopes, for 39 scoria and lava samples collected along the fissure, together with analyses of the rhyolitic Askja-Skolli (Askja-S) tephra previously linked to the same eruptive event.</div><div>The geochemical uniformity indicates the SRF magma was derived from a compositionally homogeneous reservoir that experienced minimal modification during transport. The geochemical similarity between the SRF and the sub-glacial and early-Holocene eruptive products of the Askja central volcano, combined with their shared rift-axis alignment, supports the magma system beneath Askja as the source. The SRF eruption was likely contemporaneous with the Plinian Askja Skolli event that deposited the Askja-S tephra across distal reaches of the fissure. We suggest that rift initiation released accumulated tectonic stress, driving magma withdrawal from a mid-crustal (∼8–10 km) reservoir beneath Askja. The resulting release of tectonic stress triggered eruption and caldera collapse, which in turn further facilitated lateral magma transport into the SRF. The eruption of the SRF into ice-free and lower-elevation terrain suggests that topographic gradient likely influenced vertical and horizontal magma migration.</div><div>The SRF represents one of the longest Holocene fissure eruptions in the NRZ, with lateral magma transport extending ≥135 km. Its timing coincides with rapid deglaciation (∼10–12 ka) in northeast Iceland, when ice unloading and lithospheric rebound enhanced melt production and eruption rates.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"472 ","pages":"Article 108557"},"PeriodicalIF":2.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatiotemporal evolution of ground deformation on Nishinoshima Island (Japan) during 2014–2020: Insights from ALOS-2/PALSAR-2 InSAR","authors":"Yuji Himematsu","doi":"10.1016/j.jvolgeores.2026.108544","DOIUrl":"10.1016/j.jvolgeores.2026.108544","url":null,"abstract":"<div><div>The appearance of a new island associated with a volcanic eruption offers an opportunity to investigate spatiotemporal characteristics of topographic evolution. This study examined the spatiotemporal evolution of ground deformation associated with the eruptive episodes on Nishinoshima Island (Japan) from 2013 to 2020 using ALOS-2/PALSAR-2 Interferometric Synthetic Aperture Radar (InSAR). Frequent lava flows during the 2013–2020 eruptive episodes formed a new islet on the southeastern part of the original island, extending its overall area. ALOS-2/PALSAR-2 InSAR during 2014–2020 revealed a line-of-sight (LOS) extension along the side of the lava flows during the eruptive episodes and in the lava-emplaced regions after previous episodes. The LOS extension along the side of the lava flows during the eruptions is interpreted as loading deformation due to lava emplacement. The best-fit loading model suggests that the pressurized extents almost coincide with the region of decorrelation, which aligns with the area emplaced with lava. In contrast, the inferred volume of emplaced lava yields ∼20% of that inferred from DEM difference. In contrast, the post-eruptive LOS extension at the lava-emplaced area is interpreted as thermoelastic deformation. The magnitude of the post-eruptive LOS extension has reached approximately 20 cm since the end of the previous eruptions, while the rate of LOS change has decreased exponentially over time. The best-fit thermoelastic deformation model indicates a heat source located at a depth of approximately 20 m, consistent with the thickness of the emplaced lava from the previous eruptive episode.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"472 ","pages":"Article 108544"},"PeriodicalIF":2.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magmatic processes in the Comei large igneous province: Insights from quantitative plagioclase composition and texture analysis","authors":"Sheng-Sheng Chen,&nbsp;Ji-Cheng Wang","doi":"10.1016/j.jvolgeores.2026.108559","DOIUrl":"10.1016/j.jvolgeores.2026.108559","url":null,"abstract":"<div><div>The Comei Large Igneous Province (CLIP) in the Tethyan Himalaya (southern Tibet) represents a major Cretaceous magmatic event, yet its origin remains debated between a mantle plume versus a passive rift model. While previous geochemical and geochronological studies have been inconclusive, quantitative textural analysis of magmatic rocks can provide critical, independent constraints on eruption dynamics and timescales—key discriminants between these hypotheses. This study focuses on the porphyritic igneous rocks of the Lakang and Sangxiu Formations, whose plagioclase phenocrysts faithfully record pre-eruptive magmatic conditions. We applied Crystal Size Distribution (CSD) analysis to plagioclase populations, supplemented by electron probe microanalysis (EPMA) of crystal zoning and alignment factor (AF) measurements. The CSDs display straight-line segments (S-CSD type) in the large-crystal domain, indicating steady-state growth in a sub-volcanic reservoir. Calculated characteristic lengths (CLs), combined with an appropriate plagioclase growth rate (10⁻¹¹ mm/s) for this system, yield magma residence times of 729–2124 years. Integrating these timescales with revised volume estimates yields high eruption rates of 0.24–3.1 km³/yr. The textural record is composite: S-CSD segments indicate time-averaged steady-state growth in a sub-volcanic reservoir, whereas complex crystal zoning and CSD inflections attest to frequent, short-term recharge events. This apparent contradiction is resolved by a model where long-term mush stability was punctuated by episodic rejuvenation. This combination—brief storage, high eruption flux, and a record of both steady growth and episodic replenishment—is best explained by a thermally buffered crystal mush system that was periodically rejuvenated. Such high-energy, high-flux dynamics are inconsistent with passive rifting but strongly support a mantle plume origin for the CLIP. This study demonstrates how multi-scale textural analysis can resolve fundamental debates in LIP petrogenesis.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"472 ","pages":"Article 108559"},"PeriodicalIF":2.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reconstruction of the plinian phase of the 7.3 ka “Akahoya” caldera-forming eruption at the Kikai caldera, Japan","authors":"Yusuke Haruta ,&nbsp;Fukashi Maeno ,&nbsp;Yujiro J. Suzuki","doi":"10.1016/j.jvolgeores.2026.108541","DOIUrl":"10.1016/j.jvolgeores.2026.108541","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Most caldera-forming eruptions begin as plinian events. These plinian phases cause magma chamber decompression and result in subsequent caldera collapse and climactic phases characterized by large-scale pyroclastic density currents (PDCs). It is thus essential to understand the eruption sequence and parameters of the plinian phases to constrain the mechanisms of caldera-forming eruption. Here we reconstruct the detailed sequence of the plinian phase of the 7.3 ka caldera-forming eruption (Akahoya eruption) at the Kikai caldera, Japan, based on a geological survey and plume modeling. The proximal facies of the plinian phase deposits indicate that the source vent was located in the western part of the caldera. The eruptive deposits can be divided into seven subunits (Units A0, A1, A2, A3, A4a, A4b, and B) based on their lithofacies. These subunits were further classified into three groups, separated by minor erosive features. The first group comprised an ash fall layer (Unit A0) distributed only in the proximal area within 20 km of the source vent. The second group comprised a pumice fall layer (Unit A1) distributed within 80 km-distance from the Kikai caldera, and overlying PDC or co-PDC fall deposits (Unit A2) distributed in the proximal area. The third group in the proximal area comprised multiple pumice fall layers (Units A3 and A4a) and PDC deposits (Unit B); whilst in the distal area it comprised up to six pumice fall layers intercalated with ash fall layers (Units A4a and A4b). The uppermost pumice fall layers of the third group (Unit A4b) exhibited a more widespread distribution. Based on fall deposit data and plume modeling, eruptive volumes and mass discharge rates (MDRs) were estimated for the three groups to be &lt;span&gt;&lt;math&gt;&lt;mn&gt;0.0013&lt;/mn&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;0.020&lt;/mn&gt;&lt;/math&gt;&lt;/span&gt; km&lt;sup&gt;3&lt;/sup&gt; (first group), &lt;span&gt;&lt;math&gt;&lt;mn&gt;0.22&lt;/mn&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;1.0&lt;/mn&gt;&lt;/math&gt;&lt;/span&gt; km&lt;sup&gt;3&lt;/sup&gt; and &lt;span&gt;&lt;math&gt;&lt;mn&gt;3.1&lt;/mn&gt;&lt;mo&gt;×&lt;/mo&gt;&lt;msup&gt;&lt;mn&gt;10&lt;/mn&gt;&lt;mn&gt;7&lt;/mn&gt;&lt;/msup&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;1.5&lt;/mn&gt;&lt;mo&gt;×&lt;/mo&gt;&lt;msup&gt;&lt;mn&gt;10&lt;/mn&gt;&lt;mn&gt;8&lt;/mn&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; kg/s (second group), and &lt;span&gt;&lt;math&gt;&lt;mn&gt;5.0&lt;/mn&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;14.0&lt;/mn&gt;&lt;/math&gt;&lt;/span&gt; km&lt;sup&gt;3&lt;/sup&gt; and &lt;span&gt;&lt;math&gt;&lt;mn&gt;5.2&lt;/mn&gt;&lt;mo&gt;×&lt;/mo&gt;&lt;msup&gt;&lt;mn&gt;10&lt;/mn&gt;&lt;mn&gt;8&lt;/mn&gt;&lt;/msup&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;2.2&lt;/mn&gt;&lt;mo&gt;×&lt;/mo&gt;&lt;msup&gt;&lt;mn&gt;10&lt;/mn&gt;&lt;mn&gt;9&lt;/mn&gt;&lt;/msup&gt;&lt;mspace&gt;&lt;/mspace&gt;&lt;/math&gt;&lt;/span&gt;kg/s (third group). The results revealed that the plinian phase of the Akahoya eruption consisted of three eruptive events: Event 1, a small-scale explosive eruption; Event 2, a plinian eruption (MDR up to &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mn&gt;10&lt;/mn&gt;&lt;mn&gt;8&lt;/mn&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; kg/s), transitioned into the eruption of small-scale PDCs; Event 3, a large-scale plinian eruption (MDR up to &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mn&gt;10&lt;/mn&gt;&lt;mn&gt;9&lt;/mn&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; kg/s) marked by continuous partial column collapses. This eruption sequence is characterized by a gradual increase in eruptive intensity and scale, similar to plinian phases of many caldera-forming erupti","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"472 ","pages":"Article 108541"},"PeriodicalIF":2.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modelled versus tracked ballistic trajectories of volcanic bombs at Stromboli (Italy)","authors":"A. Sork ,&nbsp;L. Watson ,&nbsp;B. Kennedy ,&nbsp;R.H. Fitzgerald ,&nbsp;J. Taddeucci ,&nbsp;M. Sellier ,&nbsp;P. Scarlato ,&nbsp;E. Del Bello ,&nbsp;T. Ricci","doi":"10.1016/j.jvolgeores.2026.108543","DOIUrl":"10.1016/j.jvolgeores.2026.108543","url":null,"abstract":"<div><div>Validation for computational modelling of volcanic ballistic projectiles (VBPs) has often been accomplished by replication of field-surveyed VBP distributions. However, a range of ejection parameters can result in the same impact location, with differing impact energies and therefore hazard implications. Ballistic hazard models must accurately represent the whole trajectory to better estimate ballistic energy and interpret eruption dynamics.</div><div>We examine model performance by directly measuring Strombolian VBP ejection parameters and trajectories from high-speed video and comparing with modelled trajectories using the same parameters. We illustrate the effects of velocity and size on drag. We synthesize and investigate different methods by which the Reynolds number (<em>Re</em>) - drag coefficient (C_D) relationship is incorporated into models and how this affects modelling results. Our computational model allows for application of different existing <em>Re</em>-C_D methods and direct comparison to tracked trajectories on the metrics of impact distance and peak height.</div><div>Even with validated ejection parameters and appropriate <em>Re</em>-C_D relationships, the model rarely accurately reproduces both height and distance within a 5% threshold. The most common scenario is model overestimation of both metrics. The gas jet is the largest factor contributing to this discrepancy. Significant slowing of VBPs in excess of gravity is observed while bombs are rising (and within the gas jet radius) but not while falling. Slowing in the gas jet is potentially caused by friction with ash and lapilli, surface temperature effects, or other fluid dynamics effects.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"472 ","pages":"Article 108543"},"PeriodicalIF":2.3,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Granophyric crystallization within the Gomez Tuff, the world's largest pantelleritic ignimbrite, Davis Mountains, Trans-Pecos Texas","authors":"Don F. Parker ,&nbsp;John C. White ,&nbsp;Kevin Urbanczyk","doi":"10.1016/j.jvolgeores.2025.108527","DOIUrl":"10.1016/j.jvolgeores.2025.108527","url":null,"abstract":"<div><div>The Gomez Tuff was erupted ∼37 Ma as an explosive component of widespread silicic lava (“flood rhyolite”). The Gomez eruption covered an area &gt; 4000 km², with an estimated dense rock equivalent volume of ∼220 km³, making it the largest known pantelleritic ignimbrite. The eruption formed a ∼18 × 24 km-diameter caldera, within which the ignimbrite ponded to thicknesses approaching 500 m. Estimated water content (∼1.9 wt%) of the erupting magma was relatively low, favoring eruption of dense pyroclastic flows over pyroclastic falls. Within thicker sections of the tuff, rheomorphic flow created flow banding, large folds and ramp structures. Granophyric crystallization (af, cpx, aenig, amph, qz) destroyed the fragmental nature of the tuff, except for abundant lithic inclusions.</div><div>Gomez phenocryst assemblages include alkali feldspar (Or₃₆_–₃₉) and quartz ± fayalite, with minor hedenbergite, ilmenite and apatite. Magmatic conditions previously deduced from these assemblages assuming <em>P</em> = 2 kbar, a magmatic temperature of ∼750 °C from phase equilibria and not using fayalite in the calculations indicated a temperature range of ∼870 to 750 °C, with oxygen fugacity (ΔFMQ ∼ −1.92) below the NNO buffer (<span><span>Parker and White, 2008</span></span>). Alternative calculations suggest ranges of 855 to 766 °C, assuming fayalite stable in all samples, and 900 to 700 °C, assuming aenigmatite was stable in lieu of fayalite. The calculations assuming neither fayalite nor aenigmatite was stable as a phenocryst are preferred, as fayalite was only observed in two samples and aenigmatite was not observed as a phenocryst in any sample.</div><div>The original Peralkalinity Index (P·I.) was likely ∼1.3. During granophyric crystallization (at ∼687 °C) in thick sections of the tuff, groundmass feldspar increased its iron content and became more potassic, driving glass and calculated groundmass compositions to ∼1.48. In the final stages of crystallization, groundmass pyroxene approached stoichiometric aegirine and arfvedsonite became less magnesian and more sodic, suggesting that the P·I. of the final crystallizing glass neared 1.8, judging from comparison to the Type 1 Green Tuff of Pantelleria.</div><div>We model the Gomez magma chamber as an extensive sill, in which pantelleritic magma accumulated above a reservoir of trachytic magma. Eruption of the ignimbrite efficiently drained the evolved magma, allowing the eruption of trachyte lava, which subsequently filled the caldera.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"471 ","pages":"Article 108527"},"PeriodicalIF":2.3,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145979052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hyperspectral imaging, mineralogy, and degassing: Exploring the volcanic hydrothermal system of Red Crater, Tongariro, Aotearoa New Zealand","authors":"Daniel Sturgess ,&nbsp;Gabor Kereszturi ,&nbsp;Agnes Mazot ,&nbsp;Rachelle Sanchez ,&nbsp;Antonio M. Álvarez-Valero ,&nbsp;Vladyslav Zakharovskyi","doi":"10.1016/j.jvolgeores.2026.108535","DOIUrl":"10.1016/j.jvolgeores.2026.108535","url":null,"abstract":"<div><div>Hydrothermal alteration on volcanoes can compromise the strength and permeability of the host rock, contributing to flank collapses (e.g., Te Maari, 2012) and phreatic eruptions (e.g., Whakaari, 2019). Alteration processes occur at volcanoes hosting hydrothermal systems, where hot, acidic fluid flow is driven by a supply of magmatic heat and gas inputs, resulting in the dissolution of primary minerals and the deposition of secondary assemblages. We investigated hydrothermal alteration at Red Crater, Tongariro, Aotearoa New Zealand, using a combination of laboratory and airborne hyperspectral imaging, mineralogical, and geochemical techniques. Two distinct alteration styles were identified: (1) advanced argillic alteration, characterised by amorphous silica, kaolinite, and alunite, primarily focused at the Red Crater scoria cone, and (2) silicification at Oturere and the Emerald Lakes. The distribution of these units was mapped using supervised image classification of airborne hyperspectral data. Textural and isotopic analyses suggest acid-sulphate alteration is primarily driven by the oxidation of rising H₂S in a steam-heated environment. Red Crater hosts four main regions of heightened degassing, coinciding with geothermal surface features and hydrothermal alteration deposits, with 26.2 <span><math><mo>±</mo></math></span>1.5 t/d of CO₂ emissions and an H₂S flux of 131.1 g/m²/d. This study presents a conceptual model of hydrothermal alteration processes at Red Crater. Our mapping of alteration and degassing can indicate areas of potential future hazards, and may support simulations assessing flank instability, improving hazard assessment at this active vent.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"471 ","pages":"Article 108535"},"PeriodicalIF":2.3,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146038344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unravelling the volcanic history of the Campanian Plain: A detailed study of mid-distance successions between 40 and 130 ka","authors":"F. Totaro ,&nbsp;P. Petrosino ,&nbsp;I. Arienzo ,&nbsp;M.A. Di Vito ,&nbsp;M. Petrelli ,&nbsp;B.R. Jicha ,&nbsp;M. D'Antonio","doi":"10.1016/j.jvolgeores.2026.108531","DOIUrl":"10.1016/j.jvolgeores.2026.108531","url":null,"abstract":"<div><div>The effectiveness of tephrochronology in reconstructing past events at high resolution relies heavily on accurate knowledge of the eruptive history of volcanic sources. For the Campanian Plain, southern Italy, distal and ultra-distal tephra archives provide detailed geochemical and chronological records of its complex volcanism. In contrast, proximal studies often depend on whole-rock geochemistry from outcrops that are frequently incomplete due to erosion or burial, limiting direct comparisons with glass-based datasets from distal sites. However, mid-distance buried successions offer a crucial archive, preserving volcanic layers often absent in proximal settings. This study investigates two mid-distance successions retrieved from boreholes—Camaldoli della Torre (CdT) and San Marco Evangelista (SME)—and selected samples from the distal San Gregorio Magno (SGM) core covering the 130–40 ka interval. All three boreholes are located in the Campania region (Italy). Through a multi-method analytical approach, including major and trace elements, Sr-Nd isotopes, and new ⁴⁰Ar/³⁹Ar dating, we characterize key tephra layers and identify previously unrecognized correlations to widespread Mediterranean tephra markers. Additionally, we evaluate the potential of using whole-rock geochemical data for correlation with glass compositions from distal sites, in order to assess whether such comparisons can be reliably employed in tephrostratigraphic studies. Our findings highlight the pivotal role of buried successions in reconstructing a more complete volcanic record revealing the additional occurrences of key Mediterranean tephra markers.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"471 ","pages":"Article 108531"},"PeriodicalIF":2.3,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928329","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reconstruction of the eruptive processes and new 40Ar/39Ar dating of Plio-Pleistocene monogenetic volcanism in the Folded Middle Atlas (Northern Morocco). Implications of eruption style variation with climate changes","authors":"Said Haidatte ,&nbsp;Károly Németh ,&nbsp;Abdelilah Fekkak ,&nbsp;Hind El Hachimi ,&nbsp;El Houcine El Haous ,&nbsp;Omar Outaaoui ,&nbsp;Michele Lustrino","doi":"10.1016/j.jvolgeores.2026.108530","DOIUrl":"10.1016/j.jvolgeores.2026.108530","url":null,"abstract":"<div><div>During the Plio-Pleistocene, several individual monogenetic volcanoes were emplaced in the Folded Middle Atlas region in Central Morocco. These eruptions are primarily concentrated on anticlinal ridges and are structured by a network of NNE-SSW-oriented faults, inherited from Alpine or older tectonic phases. This study investigates three Pleistocene (2.5-0.8 Ma) small scoria cones and one partially preserved maar, here dated with ⁴⁰Ar/³⁹Ar geochronology to 0.281 Ma, indicating the youngest hydrovolcanic eruption of this area.</div><div>The temporal distribution and morphological diversity of volcanic edifices in northern Africa during the Plio-Pleistocene are inferred to be closely associated with paleoclimatic fluctuations, which alternated between arid and humid phases. Strombolian explosive eruptions created scoria cones primarily during arid periods, facilitating magmatic outgassing with minimal interaction between magma and the water table. In contrast, hydrovolcanic eruptions were promoted by wetter climatic conditions, which were susceptible to interaction between upwelling magma and surface water or shallow aquifers.</div><div>Scoria cones consist of pyroclastic deposits of varying grain sizes, including scoriaceous pyroclasts such as small portions of coarse ash lapilli and volcanic bombs with different morphologies. Their last eruptive activity phases are typically represented by thin lava flows, indicating a gradual shift to Hawaiian-type mild explosive dynamics. Conversely, maar formations are characterized by ejecta deposits from phreatomagmatic explosions, indicating rapid interaction between magma and varying volumes of external water, likely occurring during a single eruptive event.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"471 ","pages":"Article 108530"},"PeriodicalIF":2.3,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}