Journal of Volcanology and Geothermal Research最新文献

{"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":"2025-12-01","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":"Characterization of volcanic stages using seismic features: Case of Tajogaite (2021) and Colima (2013−2022)","authors":"Pablo Rey-Devesa ,&nbsp;Jesús M. Ibáñez ,&nbsp;Ligdamis Gutiérrez ,&nbsp;Janire Prudencio ,&nbsp;Aarón Álvarez-Hernández ,&nbsp;Mauricio Bretón ,&nbsp;Raúl Arámbula ,&nbsp;Félix Ortigosa ,&nbsp;Imelda Plasencia ,&nbsp;Alberto Ardid ,&nbsp;Luca D'Auria ,&nbsp;Nemesio Pérez ,&nbsp;Manuel Titos ,&nbsp;Carmen Benítez","doi":"10.1016/j.jvolgeores.2025.108454","DOIUrl":"10.1016/j.jvolgeores.2025.108454","url":null,"abstract":"<div><div>This study proposes a novel approach to volcano seismic monitoring by analyzing the time evolution of specific seismic parameters—Shannon Entropy (SE), Frequency Index (FI), and Kurtosis—with the aim of improving the forecasting, characterization, and definition of the end of eruptive episodes. We focus on two well-studied volcanoes: Volcán de Fuego de Colima (Mexico) and the Tajogaite eruption (La Palma, Spain) that occurred in 2021.</div><div>For Volcán de Fuego de Colima, we analyze a 10-year seismic dataset (2013–2022) that spans periods of high volcanic activity—including dome growth, lava flows, and explosive events—as well as intervals of relative quiescence. Our analysis suggests that SE is a useful parameter for identifying the onset of intense eruptive phases, dome growth episodes, and transitions to dormant stages. When combined with FI and Kurtosis, these parameters provide insights into specific eruptive processes such as magma ascent, conduit pressurization, and fracture generation. SE decreases when seismic signals become more organized, which typically occurs just before eruption. FI highlights changes in dominant frequency bands associated with different types of activity, while Kurtosis detects impulsive seismic events. These features thus help constrain the interpretation and potential modeling of subsurface eruptive mechanisms<strong>.</strong></div><div>In the case of the 2021 Tajogaite eruption, our method forecasted the eruption at least nine hours in advance. The joint analysis of SE, FI, and Kurtosis also allowed us to determine the end of the eruptive process, marked by a clear change in SE that coincided with the last visual evidence of volcanic activity.</div><div>Overall, this study highlights the potential of combining these seismic parameters for real-time volcano monitoring, eruption forecasting, and the characterization and modeling of eruptive processes, ultimately contributing to the improvement of early warning protocols in volcanic hazard management.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108454"},"PeriodicalIF":2.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145267508","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":"Sources of helium and associated heat in hydrothermal fluids from the central western branch of the East African Rift System (Democratic Republic of Congo and Burundi)","authors":"Wisdom Kambale Kavyavu ,&nbsp;Daniele L. Pinti ,&nbsp;Bienfait Kambale Simisi ,&nbsp;Dario Tedesco","doi":"10.1016/j.jvolgeores.2025.108464","DOIUrl":"10.1016/j.jvolgeores.2025.108464","url":null,"abstract":"<div><div>The area around Lake Kivu, situated in the western branch of the East African Rift System (WBEARS), which spans the Democratic Republic of Congo, Rwanda, and Burundi, is characterized in its southern part by numerous hot springs. Chemistry and isotopic signatures of hydrothermal fluids have been studied in the northern part of Lake Kivu due to the presence of one of the world's active volcanoes, Nyiragongo. However, the areas along the coast of Lake Kivu, extending south to the shores of Lake Tanganyika, where active volcanism is currently absent, have been largely overlooked, despite the presence of several tens of hydrothermal manifestations with temperatures ranging from 25 to 86 °C, located in a highly faulted region characterized by low to moderate seismicity. This study aimed to fill the gap by collecting samples from 15 hot springs, four lake waters, and one cold spring, located in the Democratic Republic of Congo and Burundi. Stable isotopes of water (δ²H and δ ¹⁸O), noble gas isotopes of He, Ne, and Ar, Sr isotopic ratio (⁸⁷Sr/⁸⁶Sr), and major ions and trace elements were measured. Most water samples are classified as Na-K-HCO₃ or Ca-Mg-HCO₃ types. Stable isotopes indicate that the waters are of meteoric origin. The helium isotopic ratios (³He/⁴He or R), normalized to the atmospheric ratio (Ra = 1.384 × 10⁻⁶), range from 0.058 to 1.304, indicating a dominant crustal helium source and a maximum of 13 % of mantle helium. The ⁸⁷Sr/⁸⁶Sr ratios range from 0.70362 in the Lac Vert sample, typical of mafic volcanic products, to 0.77520 in hot springs of the Ruzizi basin, a very radiogenic value possibly indicating water-rock interaction with the Proterozoic silicate basement of Central Africa. The ⁸⁷Sr/⁸⁶Sr shows a rough trend with the ⁴⁰Ar/³⁶Ar ratios, indicating a slightly detectable terrigenic ⁴⁰Ar* excess in hot spring water. These results contrast with those on the northern shore of Lake Kivu, which are characterized by magmatic helium, suggesting that moving further south, the heat is controlled by the local geothermal gradient, with fluids likely circulating deeper into the crust and warming up. This circulation is facilitated by the extensional faults of the African rift, where most of the hot springs are located. Calculated low crustal fluxes of helium in the Lake Kivu region are insufficient to create economically valuable helium reserves, as found in the southern termination of the WBEARS, in the Rukwa Rift Basin.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108464"},"PeriodicalIF":2.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145363368","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":"Contrasting magmatic structures and tectonic controls from integrated gravity and magnetic data in the Bromo–Tengger–Semeru complex and the Lamongan Volcanic Field, East Java, Indonesia","authors":"Khalil Ibrahim ,&nbsp;Satria Bijaksana ,&nbsp;Mirzam Abdurrachman ,&nbsp;David Prambudi Sahara ,&nbsp;Putu Billy Suryanata ,&nbsp;Sitti Zulaikah ,&nbsp;Rezki Wirawan ,&nbsp;Ulvienin Harlianti ,&nbsp;Thomas Andre Maris Widagdo ,&nbsp;Silvia Jannatul Fajar ,&nbsp;Yohansli Noya ,&nbsp;Ni Komang Tri Suandayani","doi":"10.1016/j.jvolgeores.2025.108455","DOIUrl":"10.1016/j.jvolgeores.2025.108455","url":null,"abstract":"<div><div>This study aims to clarify how contrasting tectonic regimes influence magma storage, connectivity, and emplacement in spatially adjacent volcanic systems within a single arc segment in East Java, Indonesia. We focus on the polygenetic Bromo–Tengger–Semeru (BTS) complex and the Lamongan Monogenetic Volcanic Field (LMVF), employing integrated gravity and magnetic approaches including Bouguer anomaly modeling, 3D Euler and 2D Werner deconvolution, constrained gravity inversion, and magnetic edge detection. A vertically extensive, lens-shaped high-density body is imaged beneath BTS between 5 and 20 km depth, with indications of lateral connectivity between Semeru and Bromo aligned along N-S compressional structures. In contrast, LMVF shows only shallow, dyke-like intrusions (&lt;2.5 km) aligned with NW–SE and NE–SW faults, spatially correlated with maar lakes and cinder cones. These findings support a model in which compressional tectonics in BTS promote deep, laterally connected magma reservoirs, while extensional faulting in LMVF facilitates shallow, structurally guided intrusions. This comparative analysis highlights the role of tectonic segmentation in shaping magmatic structure and provides a replicable framework for integrated geophysical analysis of arc volcanism.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108455"},"PeriodicalIF":2.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145221842","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":"Discrimination between dome-forming and explosive eruptions in the stratigraphic record – field, textural and petrographic evidence from the Taiheizan eruption, Mt. Sanbe, Japan","authors":"Andreas Auer ,&nbsp;Keiko Suzuki-Kamata ,&nbsp;Tetsuya Kogure ,&nbsp;Daisuke Endo ,&nbsp;Hiroshi Kitagawa ,&nbsp;Shun Orui ,&nbsp;Katsura Kobayashi","doi":"10.1016/j.jvolgeores.2025.108462","DOIUrl":"10.1016/j.jvolgeores.2025.108462","url":null,"abstract":"<div><div>Arc volcanoes often show an alternating behaviour between explosive and effusive activity. Although considered an effusive phenomenon, emplacement of highly evolved lava domes is almost always accompanied by explosive activity and processes that initiate the formation of pyroclastic density currents. Lava dome forming eruptions have distinct hazard patterns and whether a specific volcano has produced lava domes during its history is important. While the presence of a lava dome is self-evident for modern (witnessed) eruptions – the question becomes more difficult for deposits in the stratigraphic record. We here review the most recent eruption of Sanbe Volcano, SW Japan, and highlight challenges in the discrimination between explosive and effusive eruption styles. The Taiheizan eruption produced a large number of deposits from pyroclastic density currents (PDC) of the block and ash flow type, leading to the undisputed interpretation that an active lava dome was present during this eruption about 4000 years ago. However, re-evaluation of the deposits suggests they formed by eruption column collapse during a Plinian eruption. The term “block and ash flow deposit” (a descriptive expression for a deposit with a bimodal grainsize distribution), is often tied to an interpretation (formed by lava dome collapse) in the volcanological literature. There are many processes around active volcanoes that can produce deposits with large blocks in a fine-grained matrix and a dominantly bimodal GSD. This makes recognition of dome forming eruptions in the eruptive record challenging but also gives room for misinterpretation. Beside our re-evaluation of the Taiheizan eruption style, we provide a list of features that can help to identify dome forming eruptions in the stratigraphic record.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108462"},"PeriodicalIF":2.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145333271","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":"Tracking changes in the tremor sources associated with a Gorely Volcano degassing episode in 2013","authors":"Yaroslav Berezhnev ,&nbsp;Nadezhda Belovezhets ,&nbsp;Nikolai M. Shapiro ,&nbsp;Sergei Abramenkov ,&nbsp;Ivan Koulakov","doi":"10.1016/j.jvolgeores.2025.108452","DOIUrl":"10.1016/j.jvolgeores.2025.108452","url":null,"abstract":"<div><div>Gorely, one of the most active volcanoes in Kamchatka, experienced a long period of degassing from 2010 to 2013. This degassing has been accompanied by intense seismovolcanic activity in form of nearly continuous tremors that were recorded by a temporary network of seismographs. To better understand the relationship between the volcanic degassing and seismic signals, we analyze here three months of continuous seismic data of 15 stations operated in 2013 using the network covariance matrix approach. We identified a high-coherence seismovolcanic tremor in the 0.5–5 Hz frequency band and examined its temporal variations by analyzing the spectral width of the covariance matrix. Tremor sources were located and clustered based on the first eigenvectors of the covariance matrix. We identified three sequential tremor source clusters active throughout the observation period. Most of tremor sources were located beneath Gorely within the volcanic edifice, above 1 km depth. A small group of sources located at depths up to 3 km below sea level is aligned along a nearly vertical conduit-like structure. When the seismic activity switched from cluster 1 to cluster 3 in mid-October 2013, the tremor sources were slightly shifted toward northeast. During the period of cluster 1 (before October 15, 2013) the peaks of low tremor coherence coincided with the precipitation. Based on the frequency distribution of high-coherence signals, source locations and volcanological observations, we suggest that the tremor activity is controlled by complex gas dynamics within the volcano and its interaction with infiltrating meteoric fluids in Gorely's conduit system.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108452"},"PeriodicalIF":2.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145159447","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":"Seismic imaging of mid-crustal heterogeneity beneath geothermal systems, central Taupō Volcanic Zone, New Zealand","authors":"Stephen Bannister ,&nbsp;Edward A. Bertrand ,&nbsp;Geoff Kilgour ,&nbsp;T. Grant Caldwell ,&nbsp;Isabelle Chambefort ,&nbsp;Wiebke Heise ,&nbsp;Sandra Bourguignon","doi":"10.1016/j.jvolgeores.2025.108448","DOIUrl":"10.1016/j.jvolgeores.2025.108448","url":null,"abstract":"<div><div>The Taupō Volcanic Zone (TVZ) in New Zealand is a region of highly productive Quaternary volcanism and high hydrothermal heat flux. We investigate the mid-crustal seismic velocity structure of a region within the central, rhyolitic part of the TVZ encompassing high-temperature geothermal systems (e.g. Wairakei, Rotokawa). Using double-difference tomographic inversion of local earthquake data we derive 3-D models of P-wave velocity (<em>Vp</em>) and <em>Vp/Vs</em> for the subsurface. Both high (<span><math><mo>&gt;</mo></math></span> 6.0 km/s) and low (<span><math><mo>&lt;</mo></math></span> 5.5 km/s) <em>Vp</em> heterogeneities are seen in the mid-crust between 5 and 11 km depth. Regions with high <em>Vp</em> are interpreted to indicate the presence of solidified, more mafic, material within an otherwise quartzo-feldspathic crust, while regions with low <em>Vp</em> values are inferred to represent bodies of crystal-rich magma with a low melt fraction. Using the new 3-D velocity model we then relocated <span><math><mo>∼</mo></math></span>9100 earthquakes recorded between 2009 and 2022. The relocated seismicity is strongly clustered, including in the vicinity of some of the geothermal systems (e.g. Rotokawa) where fluid is currently being extracted for electric-power production. Mid-crustal seismicity is also observed west of the Wairakei geothermal field, as well as along the south-eastern margin of the Ngakuru graben and on the western margin of the Whakamaru caldera. The depth distribution of the highest-quality hypocentres shows that 90% of the seismicity at Rotokawa geothermal field occurs at depths shallower than 5.1 km, consistent with a shallow brittle–ductile transition and the presence of a cooling pluton beneath Rotokawa seen in magnetotelluric data.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108448"},"PeriodicalIF":2.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145159448","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":"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":"2025-12-01","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":"2025-12-01","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":"Mosaic nature of seismicity patterns associated with eruptions of the Klyuchevskoy Volcano (Kamchatka, Russia)","authors":"A.A. Shakirova,&nbsp;V.A. Saltykov","doi":"10.1016/j.jvolgeores.2025.108477","DOIUrl":"10.1016/j.jvolgeores.2025.108477","url":null,"abstract":"<div><div>The Klyuchevskoy Volcano (Russia, Kamchatka Peninsula) has been erupting almost annually since 2003. All its eruptions are preceded by high seismic activity. The Statistical Estimation of Seismicity Level (SESL’09) methodology was applied to analyze the seismicity of the Klyuchevskoy Volcano. This scale is based on the statistical distribution function of seismic energy and characterizes the seismicity level of a given spatial object over a specific time interval. The SESL’09 was applied to the Klyuchevskoy Volcano earthquake catalog starting from 1999. The dynamics of seismicity were analyzed in four the most seismically active zones beneath Klyuchevskoy: Surface layer (depth: −4 to 2 km), near-surface layer (depth: 4 to 8 km), intermediate layer in the crust-mantle boundary (20 to 25 km), deep layer (26 to 34 km), as well as the low-seismicity layer (9 to 17 km). A mosaic nature of seismicity patterns was identified in the vicinity of 10 out of 11 summit eruptions that occurred between 2003 and 2024. The most pronounced increase in seismicity – reaching high and extremely high levels, ranged from 6 to 482 days, depending on depth: in near-surface layer 6–167 days before eruption, in intermediate layer <strong>7–</strong>273 days before eruption, in intermediate layer 52–482 days, in deep layer 10–465 days. Two major eruptions in 2013 and 2023 were preceded by level of seismicity escalation two years in advance, and their exceptional intensity was likely driven by prolonged magma accumulation within the volcano's conduit system.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108477"},"PeriodicalIF":2.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145424716","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}