Journal of Volcanology and Geothermal Research最新文献

{"title":"Insights on the multi-scale topographic features of Mt. Etna volcano (Italy)","authors":"Salvatore Scudero ,&nbsp;Gianluca Groppelli","doi":"10.1016/j.jvolgeores.2025.108443","DOIUrl":"10.1016/j.jvolgeores.2025.108443","url":null,"abstract":"<div><div>The terrain analysis of volcanic landforms provides valuable qualitative and quantitative insights into the factors that shape volcanoes. Using different terrain analysis approaches, this study reconstructs and describes the multi-scale topographic features of Mt. Etna Volcano (Italy). Specifically, the first order shape of the volcano, approximating the large-scale volcanic edifice, is characterized through the analytical fitting of contour lines using an elliptical geometry. The geometric properties of this modelled surface align with the evolutionary phases of Mt. Etna over the past 300 kyr. The modelled surface also serves as a two-dimensional filter: the residual topography, obtained by its removal from the actual topography, reveals second-order topographic features. The residual topography is then opportunely resampled and analysed using the wavelet technique along slope-parallel and base-parallel sections. This analysis reveals zones with different wavelength behaviours that correlate with the residual topographic anomalies. The spatial arrangement of this anomalies around the flanks of the volcano aligns with known volcanic features of Mt. Etna, such as the “Ellittico” volcano and its caldera depression, the large volcano-tectonic depression of the “Bove” valley, and the unstable eastern flank. A few zones do not correspond to any recognized features and may suggest the occurrence of buried structures, offering potential targets for future investigation. This study demonstrates that the wavelet-based technique is a valuable tool for characterizing and classifying volcanic landforms.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108443"},"PeriodicalIF":2.3,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145159450","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":"The hydrothermal system prior to a phreatic eruption: The case of the 1873 eruption at La Fossa (Vulcano Island, Italy)","authors":"Silvia Giansante ,&nbsp;Paolo Fulignati ,&nbsp;Anna Gioncada ,&nbsp;Marco Pistolesi ,&nbsp;Tomaso Esposti Ongaro ,&nbsp;Antonio Tazzini ,&nbsp;Raffaello Cioni","doi":"10.1016/j.jvolgeores.2025.108445","DOIUrl":"10.1016/j.jvolgeores.2025.108445","url":null,"abstract":"<div><div>Steam-driven eruptions, such as phreatic and hydrothermal explosions, likely represent some of the most frequent eruptive styles at stratovolcanoes. However, deciphering their timing, dynamics, and underlying mechanisms from eruptive deposits remains a significant challenge, even when, although such deposits are thin, altered, poorly dispersed, and strongly altered, they have not been removed by erosion. Lithic fragments from these eruptions can however preserve valuable information on lithology, pre-eruptive conditions, and the physico-chemical state of the disrupted aquifer. Here we examine the lithic fragments of the “Breccia De Fiore” deposit, emplaced by multiple explosions during a 44-day-long 1873 eruptive phase at La Fossa di Vulcano (Italy). The deposit consists of five poorly sorted lapilli tuff to tuff breccia beds, rich in hydrothermally altered lithics, lacking juvenile material. Petrographic, mineralogical, and geochemical analyses reveal a lithology dominated by silicic and advanced argillic altered particles (44–60 % vol%), together with 23–31 vol% devitrified quartz-bearing fragments hosting vapour-rich fluid inclusions–, and 7–27 vol% unaltered material. These features suggest the disruption of a shallow, acid-sulphate hydrothermal system, a rhyolitic plug occupying the shallow crater-conduit system, and unaltered adjacent lithologies. Quartz textures and fluid inclusions point to vapour-dominated conditions and explosions driven by episodic failure of sealed vapour-pockets within the shallow hydrothermal system, repeatedly recharged by magmatic gas flux. We interpret the 1873 steam-driven eruptions as a series of phreatic explosions occurring in a shallow hydrothermal system under conditions of alteration-driven permeability reduction and magmatic gas and heat input. These results underscore the role of alteration and sustained fluid supply into the hydrothermal system in driving prolonged, non-magmatic explosive activity at Vulcano.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108445"},"PeriodicalIF":2.3,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106948","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":"Pillow flows of rhyolite rheoignimbrite exposed in the Fukube Falls, Hakusan-Shirakawago White Road","authors":"Susumu Umino","doi":"10.1016/j.jvolgeores.2025.108444","DOIUrl":"10.1016/j.jvolgeores.2025.108444","url":null,"abstract":"<div><div>The Fukube Falls in the upper Jadani River exposes successive layers of essentially subaerial ignimbrite of the 70 Ma Futomiyama Group, that intervenes a rheoignimbrite layer of giant pillows. The pillowed layer extends 320 m from east to west and varies in thickness from 15 m to 84 m. The bifurcating pillow lobes indicate that the western, central and eastern pillows flowed southward, eastward and southwestward, respectively. The pillow lobes range from 1 to more than 9 m in height and from 1 to 13 m in width, with an average of 3.4 ± 1.6 m and 4.2 ± 2.1 m, respectively. The height/width ratio is 0.78, which is similar to the ranges for tholeiite pillows of the Recent Loihi Seamount, Hawaii, and larger than those of the Cretaceous Oman Ophiolite. The obsidian glass of the pillow margin has a rhyolitic composition with 77 mass% SiO₂. The magma temperature is estimated from 782 °C to 810 °C, depending on the water content, based on the hornblende geothermometer. Analogue experiments on pillow lobe height constrain the upper and lower limits of extrusion rate and viscosity of the rheoignimbrite. In addition, the Devorah number, the ratio of rate of strain accumulation to the rate of strain relaxation, also gives the maximum viscosity and extrusion rate that allows for the formation of coherent pillows without fragmentation. Based on these constraints, the conditions of pillow lobe formation are viscosities ranging from 10^4.5 Pa·s to 10^6.8 Pa·s, and extrusion rates from 2.4 × 10⁻³ m³/s to 3.1 × 10³ m³/s for point sources and from 2.4 × 10⁻³ m²/s to 3.1 × 10² m²/s for line sources. Such viscosities require water contents of the magma more than 1.4 mass%, suggesting the hydrous welding of ignimbrite that was initially extruded on land and was emplaced under water-saturated conditions.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108444"},"PeriodicalIF":2.3,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145107581","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":"Geochemical characterisation of major silicic explosive eruptions from the Azores in the last ∼100 kyrs","authors":"Emma L. Horn ,&nbsp;Danielle McLean ,&nbsp;Adriano Pimentel ,&nbsp;José M. Pacheco ,&nbsp;Simone Aguiar ,&nbsp;Christina J. Manning ,&nbsp;CAVES Project Team,&nbsp;Nick Barton ,&nbsp;Victoria C. Smith","doi":"10.1016/j.jvolgeores.2025.108446","DOIUrl":"10.1016/j.jvolgeores.2025.108446","url":null,"abstract":"<div><div>Volcanoes in the Azores have experienced large, silicic explosive eruptions, and these events have been concentrated mostly on the islands of São Miguel and Terceira. It is evident these eruptions are capable of dispersing tephra thousands of kilometers, owing to distal sedimentary sequences in Europe and Africa recording tephra sourced from the Azores, but the lack of detailed glass geochemical datasets precluded robust distal correlations to specific eruptions. Establishing the glass compositions of these large pyroclastic deposits will allow these Azores tephra to serve as chronostratigraphic markers. Here we present the major and trace element glass geochemical compositions of the largest known eruptions from Sete Cidades, Fogo, and Furnas volcanoes on São Miguel, and Pico Alto/Guilherme Moniz on Terceira. The glasses are predominately trachytic with 60.5–67.5 wt% SiO₂, 12–19 wt% Al₂O₃, 1–7 wt% FeOt, Eu &lt;6.5 ppm, Zr &lt;2400 ppm, and Yb &lt;14 ppm. A notable feature is that the glass compositions of individual deposits are diverse, and often show distinct populations that are associated with different eruption phases. The melts erupted from central volcanoes on both islands are distinctive - glasses erupted from São Miguel contain distinctively lower FeOt (&lt;4.0 wt%), and higher Al₂O₃ (&gt;16.8 wt%) and La/Y ratios (&gt;1.6 ppm) relative to those erupted from Terceira. The dataset was used to establish that a cryptotephra layer in the Taforalt archaeological site in Morocco is linked to the 18-20 cal. ka BP Santa Bárbara eruption from Sete Cidades volcano &gt;2000 km away. Interestingly, despite several tephra layers from the Azores being identified in Holocene sequences across Europe, there are no voluminous deposits on the Azores, except for Fogo A, within this timeframe. This confirms that the tephra is widely dispersed even in some of the smaller eruptions and this geochemical dataset provides a useful framework for identifying Azores tephra in Late Pleistocene distal records. However, the Azores volcanoes typically erupt compositionally diverse evolved melts that do not vary much between successive eruptions. Thus, it is often difficult to distinguish the eruption deposits based on glass compositions alone, and often chronostratigraphic information is also required to reliably correlate distal tephra to specific eruptions.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108446"},"PeriodicalIF":2.3,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106947","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":"Intense explosive activity in the early Holocene at Pico de Orizaba volcano: Revisiting the Xilomich eruptive episode","authors":"Delphine Sourisseau ,&nbsp;José Luis Arce ,&nbsp;José Luis Macías ,&nbsp;Laura E. Beramendi-Orosco ,&nbsp;José Juan Carrillo-Mondragón ,&nbsp;Galia González-Hernández","doi":"10.1016/j.jvolgeores.2025.108433","DOIUrl":"10.1016/j.jvolgeores.2025.108433","url":null,"abstract":"<div><div>Pico de Orizaba is a Pleistocene to Holocene stratovolcano located in the easternmost part of the Trans-Mexican Volcanic Belt. Repeated cycles of dome growth and collapse, along with Vulcanian to Plinian explosive activity, have occurred during the past 650 ka. These eruptions have produced a complex sequence of scoria-and-ash, pumice-and-ash, block-and-ash flows and pumice fallout, interbedded with andesitic to dacitic lava flows that constitute the modern volcanic edifice (Citlaltépetl volcano). Based on detailed field descriptions, stratigraphic correlations, grain size and componentry analyses, and five new ¹⁴C radiocarbon ages, we reconstruct the eruptive history of the Xilomich eruptive episode deposited south of Pico de Orizaba. Our results indicate that at least ten pyroclastic flows were emplaced during the Xilomich eruptive episode between 8980 and 8170 years BP. These deposits record the occurrence of at least four Vulcanian eruptions and two dome-destruction events, which generated scoria-and-ash and block-and-ash pyroclastic flows. Pyroclastic flows generated by eruptions comparable to the Xilomich episode could extend as far as populated areas like Maltrata, Ciudad Mendoza, and Orizaba, located within a 30-km radius, posing a potential threat to approximately 310,500 inhabitants south of Pico de Orizaba.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108433"},"PeriodicalIF":2.3,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145020834","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":"Age of Holocene lava flows of Pico de Orizaba from paleomagnetic data","authors":"Erick Juárez-Arriaga ,&nbsp;Katrin Sieron ,&nbsp;Harald Böhnel","doi":"10.1016/j.jvolgeores.2025.108434","DOIUrl":"10.1016/j.jvolgeores.2025.108434","url":null,"abstract":"<div><div>High-precision paleomagnetic dating offers an independent and valuable tool for constraining the ages of Holocene volcanic eruptions - particularly when other dating methods are inapplicable yield uncertain results, or are contradicted by inconsistent historical records. We applied this approach to Pico de Orizaba (Citlaltépetl), a 5653 m stratovolcano in eastern Mexico that poses a significant threat to nearly half a million people living within a 30 km radius. Despite the existence of hazard maps, the eruptive chronology of the volcano remains poorly constrained due to contradictory and uncertain published data.</div><div>The study focused on Holocene lava flows, with sampling conducted at 35 sites across 12 distinct flows located at elevations between 3500 and 4800 m. We obtained robust paleomagnetic directions and absolute paleointensity values, which were compared to the SHA.DIF.14 k global geomagnetic model. This comparison enabled us to determine well-constrained emplacement ages, further supported by the available relative stratigraphic information.</div><div>Our results refine the Holocene eruptive history of Pico de Orizaba. We correlated two lava flows with previously determined 36Cl exposure ages, rejected earlier proposed historical attributions, and establish new correlations between flows on the northern and southern flanks. The eruptive record reveals two distinct phases interrupted by activity at the parasitic Chichimeco dome complex: (1) the Malacara lava flows, which followed the Citlaltépetl/Xilomich Plinian eruption, and (2) eruptions from approximately 2100 BCE to recent times. Both phases broadly coincide with periods of glacier retreat, suggesting a possible link between deglaciation and volcanic activity. These findings significantly improve the eruptive chronology of Pico de Orizaba and provide critical data for future hazard assessments.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108434"},"PeriodicalIF":2.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145050041","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":"Magma ascent dynamics and transport process of the Mt. Semeru lava dome that collapsed on 4th December 2021 (East Java, Indonesia)","authors":"Indranova Suhendro ,&nbsp;Muhammad Andriansyah Gurusinga ,&nbsp;Atsushi Toramaru ,&nbsp;Agung Harijoko ,&nbsp;Haryo Edi Wibowo ,&nbsp;Gammanda Adhny El-Zamzamy Latief ,&nbsp;Pandu Eka Priyana ,&nbsp;Muhammad Alsamtu Tita Sabila Pratama Suhartono ,&nbsp;Zulfa Yogi Rahmawati","doi":"10.1016/j.jvolgeores.2025.108432","DOIUrl":"10.1016/j.jvolgeores.2025.108432","url":null,"abstract":"<div><div>This study aimed to discuss the magma ascent dynamics and transport process of the Mt. Semeru lava dome that collapsed on 4th December 2021 by coupling the field data with analysis of crystal textures (phenocrysts and microlites) and whole-rock geochemistry of clasts embedded in the 2021 pyroclastic density currents (PDCs) of the channel facies. We identify four clast types within the channel PDC facies, namely vesicular-black and porphyritic (V-BP), dense-grey and porphyritic (D-GP), dense-grey and highly porphyritic (D-GhP), and vesicular-reddish and weakly porphyritic (V-RwP). The V-BP, D-GP, and D-GhP clasts are free of olivine, having identical phenocryst size distribution (avg. slope − 3.0) and whole-rock composition of high Zr/Y basaltic andesites (∼56.5 wt% SiO₂; Magma A). Meanwhile, the V-RwP clast includes some olivine, has a characteristically steeper slope of the phenocryst crystal size distribution (CSD) (−3.8), and is classified as low Zr/Y basalt (∼51 wt% SiO₂; Magma B). This evidence suggests the occurrence of at least two magma reservoirs beneath Semeru. Judging from Semeru's historical record, dome formation via the extrusion of Magma A took place between 2004 and 2012, while Magma B was extruded before dome formation (between 1941 and 1994) and produced lava flows and V-RwP clasts; the latter was carried by the 2021 PDCs and thus classified as accidental lithics. The V-BP yielded the steepest CSD slope of plagioclase microlites (−50.8), followed by D-GP (−43.7) and D-GhP (−24.3), suggesting that the type A magma ascended and quenched at different rates. The less porphyritic and more gaseous magma quickly reaches the surface, resulting in V-BP with relatively small microlite size and steeper CSD. While the more porphyritic and gas-poor magma ascends slowly, resulting in slower cooling and thus facilitating the microlites to attain a larger size with gentler microlite CSD. The increasing SO₂ emissions and the presence of harmonic tremors before the collapse event suggest that the dome was destabilized by the ascending magma, forming initially hot PDCs. However, heavy rainfalls (∼15 mm/h) successfully turned the PDCs into wet and cold (&lt;100 °C) conditions, as evidenced by the prevalence of accretionary lapilli in the overbank facies and unsinged trees and wooden and plastic materials.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"467 ","pages":"Article 108432"},"PeriodicalIF":2.3,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144893509","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":"Exposing electrical conductivity anomalies beneath Mount Erciyes, Cappadocia, Türkiye","authors":"Sabri Bülent Tank,&nbsp;Serkan Üner ,&nbsp;Ruken Yazıcı,&nbsp;Mustafa Karaş","doi":"10.1016/j.jvolgeores.2025.108428","DOIUrl":"10.1016/j.jvolgeores.2025.108428","url":null,"abstract":"<div><div>Three-dimensional electrical conductivity models for Mount Erciyes, the most prominent stratovolcano at the Cappadocia Volcanic Province in Central Anatolia, Türkiye, were developed from magnetotellurics (MT) data collected at thirty-eight sounding locations. Analyses including electromagnetic impedance tensor and phase tensor calculations were employed to portray the conductivity variations, to reveal the dimensionality of the dataset and to detect the principal geo-electric strike direction in the area. Next, several trial models were developed including and excluding topography information as well as different starting models and other modeling parameters. Results achieved from all of the inverse calculations and particularly the final model suggested that (i) high electrical conductivity (&lt;10 Ωm) values are obtained for multiple anomalies distributed beneath the complex reaching to depths of around 4–6 km from the summit, (ii) these anomalies coincide with the parasitic cones and the vents associated with the Mount Erciyes, (iii) the northeast-southwest trending faults that bound the Erciyes Basin and the wrench zone that cut across the main volcano complex act as barriers for the fluid flow.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"467 ","pages":"Article 108428"},"PeriodicalIF":2.3,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144996387","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":"Kronotsky Volcano – A low-K end-member frontal volcano in Kamchatka: Geological structure and composition of rocks and minerals","authors":"Natalia Gorbach ,&nbsp;Daria Tobelko ,&nbsp;Georgy Ovsyannikov ,&nbsp;Alexey Rogozin ,&nbsp;Vasiliy Shcherbakov ,&nbsp;Anastasia Plechova ,&nbsp;Maxim Portnyagin","doi":"10.1016/j.jvolgeores.2025.108430","DOIUrl":"10.1016/j.jvolgeores.2025.108430","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Kronotsky volcano is the largest but poorly studied stratovolcano in the frontal zone of the Kamchatka arc. Here we present the first systematic data on the geological structure of this volcano and the composition of its rocks and minerals. Kronotsky lavas are predominantly low-K, high-Fe tholeiitic basalts to basaltic andesites with SiO&lt;sub&gt;2&lt;/sub&gt; = 47.0–53.2 wt%, K&lt;sub&gt;2&lt;/sub&gt;O = 0.24–0.65 wt%, FeO&lt;sup&gt;⁎&lt;/sup&gt; = 9.1–13.4 wt% and MgO = 3.7–11.2 wt%. Andesites (SiO&lt;sub&gt;2&lt;/sub&gt; = 59.9–60.5 wt%, K&lt;sub&gt;2&lt;/sub&gt;O = 0.65 wt%, FeO&lt;sup&gt;⁎&lt;/sup&gt; = 7.7–7.6 wt%, MgO = 2.4–2.6 wt%) are rare and occur among the lava cones and necks from the latest stage of activity. The major phenocrysts in Kronotsky basalts are olivine (Fo&lt;sub&gt;91.9&lt;/sub&gt;&lt;sub&gt;–&lt;/sub&gt;&lt;sub&gt;67&lt;/sub&gt;), plagioclase (An&lt;sub&gt;95&lt;/sub&gt;&lt;sub&gt;–&lt;/sub&gt;&lt;sub&gt;40&lt;/sub&gt;) and high-Ca pyroxene (Mg#&lt;sub&gt;89.3&lt;/sub&gt;&lt;sub&gt;–&lt;/sub&gt;&lt;sub&gt;50&lt;/sub&gt;). Orthopyroxene occurs as phenocrysts (Mg#&lt;sub&gt;61&lt;/sub&gt;&lt;sub&gt;–&lt;/sub&gt;&lt;sub&gt;67&lt;/sub&gt;) in the andesites and rarely in the basaltic andesites, and as inclusions (Mg#&lt;sub&gt;83&lt;/sub&gt;) in the high Ca-pyroxene glomerocrysts of the most mafic varieties of basalts. Ti-magnetite (Fe&lt;sup&gt;2+&lt;/sup&gt;/Fe&lt;sup&gt;3+&lt;/sup&gt; = 0.98–1.51, TiO&lt;sub&gt;2&lt;/sub&gt; = 11.0–16.5 wt%) forms subphenocrysts in andesites and microlites in the groundmass of basalts. Inclusions of Cr-spinel (Cr/Cr + Al = 0.19–0.79, TiO&lt;sub&gt;2&lt;/sub&gt; = 0.18–2.81 wt% and Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; = 8.7–33.2 wt%) are found in olivine phenocrysts. Variations of whole rock and mineral compositions reflect the existence of long-lived magma chamber(s) under the volcano and the processes of crystal differentiation, accumulation and magma mixing as well as crystallization associated with magma degassing during ascent and decompression.&lt;/div&gt;&lt;div&gt;Compared to all Quaternary volcanoes on Kamchatka, Kronotsky basalts are the most depleted in K&lt;sub&gt;2&lt;/sub&gt;O (down to 0.24 wt%) and a number of other incompatible elements (Ti, Zr, Nb, LREE), and are characterized by the lowest Nb/Zr (≤0.02) and Nb/Yb (≤0.5) ratios. In contrast, Ba/Nb (up to 280) and especially Ba/Th (up to 938) ratios are relatively high compared to other Kamchatka volcanoes. The composition of high-Mg olivine (Fo ≥ 87.5 mol%, Ni ≤2500 ppm, Fe/Mn = 56–71) indicates that the primary magmas of Kronotsky volcano originated from a peridotite mantle source. Trace element modeling suggests that the mantle was melted to a high degree (up to 25 %) and was more depleted than the source of typical MORB and of most parental magmas in Kamchatka. The exceptionally high degree of melting, combined with a strong relative enrichment in fluid mobile elements, suggests an enhanced fluid flux from the subducting Pacific plate beneath Kronotsky volcano, which is responsible for the extensive mantle melting. The Krusenstern fracture zone on the Pacific plate, subducting beneath central Kamchatka, may supply abundant hydrous fluids to the mantle wedge beneath Kronotsky volcano, contributing to its distinct","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"467 ","pages":"Article 108430"},"PeriodicalIF":2.3,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144893508","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":"Self-similar spatial clustering of volcanic vents: Insights into magma storage depth from global volcanic fields","authors":"Francesco Mazzarini ,&nbsp;Nicolas Le Corvec ,&nbsp;Ilaria Isola","doi":"10.1016/j.jvolgeores.2025.108431","DOIUrl":"10.1016/j.jvolgeores.2025.108431","url":null,"abstract":"<div><div>The spatial distribution of volcanic vents in volcanic fields provides critical insights into the structure of underlying magma plumbing systems and the influence of crustal structures and state of stress on magma ascent. This study investigates self-similar clustering of vents in 46 volcanic fields from diverse geotectonic settings to assess whether vent distribution consistently follows fractal patterns, regardless of parametric statistical classifications. Spatial analyses using Nearest Neighbour Distance, Vent-to-Vent Distance and Kernel Density Estimation confirm that the vent self-similar clustering is a fundamental characteristic of distributed volcanism.</div><div>The analysis reveals that self-similar clustering is present in all volcanic fields, even in cases where parametric methods suggest a random or over-dispersed distribution. The vent self-similar clustering is defined within a length range bounded by two thresholds, the lower (Lco) and the upper (Uco) cut-offs. They correspond to the shallow depth (&lt; 5 km) at which magma may accumulate without leading to eruption and the depth of the magma reservoir or dike propagation zone, respectively. A strong positive correlation between Uco and magma reservoir depth (H) suggests that vent clustering reflects subsurface magma transport dynamics. Statistical tests confirm that γ₁ and γ₂ parameters, previously defined for volcanic fields in the Main Ethiopian Rift, are effective indicators of vent clustering, with γ₁ consistently ≤0.1 for clustered fields.</div><div>These findings underscore the role of fracture networks as efficient pathways for magma ascent, supporting the hypothesis that magma effusion sites are intrinsically linked to crustal mechanical properties. Future research should explore how fracture network evolution influences vent distribution over time and whether the vent self-similar clustering analysis can improve constraints on magma reservoir dynamics and eruption forecasting. Furthermore, applying this framework to extraterrestrial volcanic fields (e.g., Mars) could provide new insights into universal processes governing vent clustering in different planetary environments.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"467 ","pages":"Article 108431"},"PeriodicalIF":2.3,"publicationDate":"2025-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144864730","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}