Journal of Volcanology and Geothermal Research最新文献

{"title":"Conduit armouring preceding explosive activity at an andesitic stratovolcano, an example from Taranaki Mounga, New Zealand","authors":"Henry Hoult ,&nbsp;Ben M. Kennedy ,&nbsp;Alexander R.L. Nichols ,&nbsp;Shane Cronin ,&nbsp;Leighton Watson","doi":"10.1016/j.jvolgeores.2024.108214","DOIUrl":"10.1016/j.jvolgeores.2024.108214","url":null,"abstract":"<div><div>The strength and permeability of volcanic conduits can directly influence eruption dynamics via moderating the outgassing of ascending magma and the density of eruption plumes. Lithic clasts in pyroclastic ejecta can be used to understand the dynamic evolution of conduit walls because they are incorporated into the ascending melt-gas-particle mixture during volcanic eruptions. We examine the 1655 CE Burrell eruption of Taranaki Mounga, which transitioned from effusive activity to an explosive sub-Plinian phase and ended in unsteady columns. This episode was followed by a series of effusive eruptions of lower explosivity. Using textural analysis and physical properties, we distinguish five dominant lithic clast types within Burrell deposits that represent different regions of the shallow conduit and vent. Lithic types 1–3 represent juvenile (‘intrusive cognate’) and older (‘intrusive accessory’) conduit-filling plug materials. Lithic type 4 represents juvenile (‘extrusive cognate’) vent-filling lava dome extruded at the eruption onset, while Type 5 lithics (‘extrusive cognate’) represent sintered/compacted cognate material from the shallow vent accumulated during transitions in eruptive style. Crystalline andesite lithics (type 1) show a microlite-dominated groundmass. Hydrothermally altered andesite lithics (type 2) show breakdown of phenocrysts and increased seismic velocity relative to type 1 lithics. Brecciated andesite lithics (type 3) comprise fractured and sintered clasts of crystalline andesite. Glassy andesite lithics (type 4) show sub-rounded vesicles and glass-hosted microlites. Banded vitrophyre lithics (type 5) show bands of varying vesicularity, crystallinity and clast load. Physical property data reveals porosity, fracturing, sintering and alteration extent dictate dynamic changes in conduit permeability and potentially strength. Our results show how, during the explosive phase of the Burrell eruption, the conduit was lined with juvenile and remnant shallow plug material that was variably fractured, sintered and altered before being eroded and ejected. Comparison with previous work on Taranaki and dome-plug material from around the world shows how fracturing and sintering of conduit walls, combined with lining with dense juvenile material, cause overall permeability reduction and strengthening of the conduit. This inhibits outgassing and preserves conduit structure, facilitating the transition to explosive activity and the establishment of a stable eruption column.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"455 ","pages":"Article 108214"},"PeriodicalIF":2.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561203","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":"Volcanic tremor associated with successive gas emission activity at a boiling pool: Analyses of seismic array and visible image data recorded at Iwo-Yama in Kirishima Volcanic complex, Japan","authors":"Masato Hata ,&nbsp;Takeshi Nishimura ,&nbsp;Takeshi Matsushima ,&nbsp;Tomofumi Kozono ,&nbsp;Tsutomu Nagatsuma ,&nbsp;Ken T. Murata ,&nbsp;Kazutaka Kikuta ,&nbsp;Dan Muramatsu ,&nbsp;Hisashi Nakahara","doi":"10.1016/j.jvolgeores.2024.108212","DOIUrl":"10.1016/j.jvolgeores.2024.108212","url":null,"abstract":"<div><div>Volcanic tremors are often observed during volcanic activity and volcanic eruptions, and their generation processes provide clues for understanding volcanic fluid activity underground and eruption dynamics. However, tremors are characterized by continuous oscillations that mask P- and S-waves; hence few studies have precisely located the source, which is the most fundamental information for understanding the generation mechanism. In this study, we focus on volcanic tremors excited by continuous gas emissions occurring at a vent called Y2a in Iwo-Yama, the Kirishima Volcanic Complex, Japan, to clarify the source process of the tremor as well as gas emission activity. We simultaneously observed the volcanic tremor by deploying a small aperture array consisting of six seismometers and the gas emission activity by using a newly developed visual IoT system that can be operated without commercial electricity. MUSIC analysis locates the tremor at depths ranging from the ground surface to approximately 200 m beneath the Y2a and Y2b vents, which are approximately 30 m apart, for approximately four months from November 2021 to February 2022. The source locations of the tremors in the 2 Hz (1.2–2.6 Hz), 4 Hz (3–4 Hz), and 5 Hz (4–5.5 Hz) ranges show some differences and changes with time. The source location tends to become deeper when the 2 Hz amplitude is large. The infrasound generated by gas emission activity is dominant in the tremor signals, which are recognized in the wave propagation velocity with an acoustic velocity of 330 m/s when the 2 Hz amplitude is small. The visual IoT system succeeded in detecting long-term changes in the gas emission activity, and we found that the 2 Hz amplitude of tremor was well correlated with the amount of hot water in the boiling pool of Y2a, which was controlled by precipitation and evaporation during non-rainy days. From these observations, we infer that the volcanic tremor is generated by resonance of volcanic gas and hot water in a crack-like structure beneath Y2a. The resonance was triggered by the counterforces of the gas emissions in the boiling pool, and the infrasound was dominant during periods of hot water depletion in the boiling pool. Temporal changes in the source depths may be caused by changes in the fluid properties, configuration of the resonator and/or the strengths of the underground sources and infrasound. Our simultaneous observations of seismic array and visual IoT system clarify that even the continuous gas emission activity that looks stable is controlled by external sources such as precipitation.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"455 ","pages":"Article 108212"},"PeriodicalIF":2.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142553131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spread and frequency of explosive silicic volcanism of the Carpathian-Pannonian Region during Early Miocene: Clues from the SW Pannonian Basin and the Dinarides","authors":"Mihovil Brlek ,&nbsp;Nina Trinajstić ,&nbsp;Sean P. Gaynor ,&nbsp;Steffen Kutterolf ,&nbsp;Folkmar Hauff ,&nbsp;Julie Schindlbeck-Belo ,&nbsp;Sanja Šuica ,&nbsp;Kuo-Lung Wang ,&nbsp;Hao-Yang Lee ,&nbsp;Elena Watts ,&nbsp;Svetoslav V. Georgiev ,&nbsp;Vlatko Brčić ,&nbsp;Marko Špelić ,&nbsp;Ivan Mišur ,&nbsp;Duje Kukoč ,&nbsp;Blair Schoene ,&nbsp;Réka Lukács","doi":"10.1016/j.jvolgeores.2024.108215","DOIUrl":"10.1016/j.jvolgeores.2024.108215","url":null,"abstract":"<div><div>Explosive silicic volcanism of the Carpathian-Pannonian Region (CPR) is increasingly recognized as the primary source of tephra across the Alpine-Mediterranean region during the Early and Middle Miocene. However, the tephrostratigraphic framework for this period of volcanic activity is still incomplete. We present new multi-proxy data from Lower Miocene ignimbrites and tephra fallout deposits from the southwestern CPR and the Dinaride Lake System and integrate them into existing datasets to better resolve the regional extent and scale of these eruptions of the CPR. Volcanic glass geochemistry indicates distal fallout tuffs deposited in the Sinj Basin are correlative with the proximal Ostoros ignimbrites from the Bükkalja Volcanic Field, indicative of regionally extensive volcanism at 17.295 ± 0.028 Ma, based on CA-ID-TIMS U<img>Pb zircon geochronology. Based on integrated tephrostratigraphic data, newly identified 17.064 ± 0.010 Ma massive rhyolitic ignimbrite deposits from the Kalnik Volcaniclastic Complex located in the southwestern CPR are correlative with the 17.062 ± 0.010 Ma Mangó massive ignimbrite found in the Bükkalja Volcanic Field located in the northern CPR. Based on these new observations of its potential areal distribution and estimated thicknesses, these two widespread ∼17.1 Ma ignimbrites represent intermediate to large caldera-forming ignimbrites, larger than previously suggested. Finally, volcanic glass geochemistry of fallout deposits from the Dinaridic Sinj and Livno-Tomislavgrad Basins have similar volcanic glass geochemistry as the rhyolitic pumices from the lowermost part of the Bogács ignimbrite unit of the Bükkalja Volcanic Field. However, high-precision geochronology indicates that these distal ashfalls were deposited at 16.9567 ± 0.0074 Ma, significantly predating the 16.824 ± 0.028 Ma emplacement of the fiamme-bearing part of the Bogács ignimbrite. These distinct ages suggest that the Bogács unit represents multiple eruptive events and indicating that further work is required to deconvolve this portion of the CPR volcanic record. Together, these data suggest that large volume CPR ignimbrite volcanism was more frequent and widespread than previously understood, enhancing the existing volcanic framework and history of the source region for this time period.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"455 ","pages":"Article 108215"},"PeriodicalIF":2.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142572255","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":"Corrigendum to “Volcanomagnetic signals related to the 2021 Tajogaite volcanic eruption in the Cumbre Vieja rift (La Palma, Canary Islands)” [Journal of Volcanology and Geothermal Research 455 (2024) 108200]","authors":"Isabel Blanco-Montenegro ,&nbsp;José Arnoso ,&nbsp;Nieves Sánchez ,&nbsp;Fuensanta G. Montesinos ,&nbsp;David Gómez-Ortiz ,&nbsp;Iacopo Nicolosi ,&nbsp;Emilio Vélez ,&nbsp;Maite Benavent","doi":"10.1016/j.jvolgeores.2024.108213","DOIUrl":"10.1016/j.jvolgeores.2024.108213","url":null,"abstract":"","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"455 ","pages":"Article 108213"},"PeriodicalIF":2.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142651769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Melt viscosity tracks the volcanic and magmatic evolution of the 2021 Tajogaite eruption, La Palma (Canary Islands)","authors":"Arianna Soldati ,&nbsp;Corrado Cimarelli ,&nbsp;Ulrich Kueppers ,&nbsp;Francisco Cáceres ,&nbsp;Dirk Müller ,&nbsp;Matthew Pankhurst ,&nbsp;Jane H. Scarrow ,&nbsp;Nemesio Perez ,&nbsp;Donald B. Dingwell","doi":"10.1016/j.jvolgeores.2024.108210","DOIUrl":"10.1016/j.jvolgeores.2024.108210","url":null,"abstract":"<div><div>After more than 50 years of repose, on September 19th, 2021, a volcanic eruption began at the Cumbre Vieja ridge on La Palma, Canary Islands. The combined effusive and explosive activity generated a &gt; 12 km² lava flow field with a new cone nearly 200 m higher than pre-eruptive topography and a vast tephra blanket. The immediate impact was locally devastating, destroying nearly 2000 buildings, blocking two main and numerous secondary roads, and inundating high-value agricultural land.</div><div>The hybrid nature of the eruption and the observed variations in eruption intensity motivated a thorough investigation of bulk liquid viscosity at high temporal resolution. Collection of 82 lava samples was achieved at a near daily resolution over the course of the 85-day-long event (through the end of the eruption on December 13th, 2021). All the samples were remelted, and liquid viscosity was measured in a concentric cylinder viscometer from 1490 °C down to incipient crystallization temperatures. These data constitute the highest temporal resolution viscosity dataset obtained for an eruptive sequence to date.</div><div>A tripartite viscosity pattern is identified at isothermal conditions: 1) during the fissure opening and establishing stage (days 1–20) a linear decrease in melt viscosity occurred; 2) during most of the eruption duration (days 21–70) viscosity was constant and 3) from day 70 until the end of the eruption viscosity increased again. We interpret this pattern as magma being extracted from different parts of the plumbing system over the course of the eruption. Accordingly, we show that viscosity time series can help shed light on some of the complexities of volcanic plumbing system. Additionally, the presented results highlight the monitoring potential of the viscosity assessment approach, specifically in regard to forecasting eruption behavior using direct information about magma mobility and detecting changes in magmatic plumbing system dynamics.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"455 ","pages":"Article 108210"},"PeriodicalIF":2.4,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142553130","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":"Melt embayments record multi-stage magma decompression histories","authors":"Behnaz Hosseini,&nbsp;Madison Myers","doi":"10.1016/j.jvolgeores.2024.108211","DOIUrl":"10.1016/j.jvolgeores.2024.108211","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Over the last decade, the melt embayment has proven its merit as a robust petrological tool capable of recording magma decompression rates for explosive eruptions. However, the models developed and applied to extract this information from embayments have not accounted for the complexity and nonlinearity of magma flow in the conduit. We present Embayment Decompression in Two Stages (EDiTS): a numerical model for extracting magma decompression rates from measured volatile diffusion profiles preserved in crystal-hosted embayments, approximating magma acceleration using two constant-rate decompression paths. This model solves for three unknown parameters: initial (deeper) and final (shallower) decompression rates, as well as the pressure where a transition occurs. We successfully benchmark EDiTS against existing numerical diffusion models, and use controlled multi-stage decompression experiments on natural quartz-hosted embayments to test the ability of our model to recover known decompression paths. We find that EDiTS is able to closely approximate the known two-stage path in the mixed-volatile (H&lt;sub&gt;2&lt;/sub&gt;O + CO&lt;sub&gt;2&lt;/sub&gt;) experiment, while a constant-rate modeling approach is unable to simultaneously fit H&lt;sub&gt;2&lt;/sub&gt;O and CO&lt;sub&gt;2&lt;/sub&gt; gradients. However, in the H&lt;sub&gt;2&lt;/sub&gt;O-saturated experiment, there is no unique solution to the resulting gradient, with both constant-rate and two-stage models reproducing the measured profile, and EDiTS notably overestimating the known total ascent time by several hours. Using decompression experiments, we show that constant-rate models can provide misleadingly good fits to embayment H&lt;sub&gt;2&lt;/sub&gt;O gradients produced by more complex decompression histories, and thus the measurement and modeling of multiple diffusing species, when available, can provide crucial constraints. We then apply EDiTS to re-evaluate mixed-volatile embayment datasets from explosive silicic arc and caldera-forming eruptions from five volcanic centers (Yellowstone, WY, USA; Valles, NM, USA; Long Valley, CA, USA; Taupo, NZ; Mount St. Helens, WA, USA). In contrast to the minutes to hours of total ascent time extracted from embayment volatile profiles using constant-rate models, our two-stage model resolves slower initial ascent times that span 3.5–11 h. Final ascent rates are 1–2 orders of magnitude faster than the initial extracted rates, in agreement with theoretical conduit flow model predictions. Reassessment of embayments from the May 18th, 1980 eruption of Mount St. Helens results in an initial stage of ascent consistent with the timing of magma arrival at the surface from the seismically-inferred storage region (7–9 km) ∼3.5 h after the initial blast, and a final stage of ascent (&lt;1–5 min) in close agreement with time-integrated bubble number densities. Our combined numerical and experimental results, and reevaluation of natural datasets, suggest that, with the application of advanced models, the melt embayment can ","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"456 ","pages":"Article 108211"},"PeriodicalIF":2.4,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The pre-Campi Flegrei caldera (>40 ka) explosive volcanic record in the Neapolitan Volcanic Area: New insights from a scientific drilling north of Naples, southern Italy","authors":"Domenico Sparice ,&nbsp;Carlo Pelullo ,&nbsp;Sandro de Vita ,&nbsp;Ilenia Arienzo ,&nbsp;Paola Petrosino ,&nbsp;Angela Mormone ,&nbsp;Gianfranco Di Vincenzo ,&nbsp;Barbara Marfè ,&nbsp;Bruna Cariddi ,&nbsp;Maddalena De Lucia ,&nbsp;Enrico Vertechi ,&nbsp;Claudia D'Oriano ,&nbsp;Paola Del Carlo ,&nbsp;Alessio Di Roberto ,&nbsp;Biagio Giaccio ,&nbsp;Giovanni Zanchetta ,&nbsp;Mauro Antonio Di Vito","doi":"10.1016/j.jvolgeores.2024.108209","DOIUrl":"10.1016/j.jvolgeores.2024.108209","url":null,"abstract":"<div><div>The oldest volcanism documented in near-vent sections around the Campi Flegrei (CF, southern Italy) caldera does not exceed ∼78 ka, even though the mid- to ultra-distal tephrostratigraphic record would suggest that activity in this area started well before that. Reconstructing the activity preceding the large caldera-forming Campanian Ignimbrite (CI) eruption of ∼40 ka, via surface geological surveys in proximal areas, is challenging because of the poor accessibility and paucity of sections recording the older chronostratigraphic interval. In order to fill the gap in knowledge of the activity preceding the CI eruption, a 113.2 m deep scientific drillhole was emplaced in the Ponti Rossi area, in the northern part of the city of Naples. The Ponti Rossi area was selected as representative of the stratigraphic setting prior to the CF caldera formation because it is close, although external, to any proposed caldera rim or downthrown area. The cored succession, consisting of pyroclastic deposits separated by paleosols, reworked humified deposits or subaerial erosional surfaces, has been logged and sampled for sedimentological, mineralogical, and geochronological analyses. Thirty-one Pyroclastic Units (PU) were identified. Based on the structural/textural features of the recovered sediments, the first relevant result is the possible absence of the CI, while the deposits of the ∼15 ka Neapolitan Yellow Tuff eruption, the second largest caldera-forming event of CF, represent the shallowest sediments. ⁴⁰Ar/³⁹Ar age determinations on alkali feldspars, extracted from juvenile fragments collected at 45.8–45.9 (PU-29) and 99.5–99.6 (PU-1) metres of depth, yielded ages of 59.03±0.50 ka and 110.00±0.35 ka, respectively. The age obtained for the deepest cored unit, having sedimentological characteristics compatible with proximal deposition, represents the oldest age obtained for a pyroclastic deposit in the sequences near the CF caldera boundaries and extends by 30 ky the explosive history of this area. Furthermore, based on ⁴⁰Ar/³⁹Ar age constraints, at least 29 eruptions, spanning the ∼59–110 ka interval, can be added to the volcanic history of the Neapolitan Volcanic Area. These eruptions can be largely attributed to the CF area, prior to the CI caldera formation, and testify to hitherto unknown, intense explosive activity.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"455 ","pages":"Article 108209"},"PeriodicalIF":2.4,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unique seismic and eruption precursors to the 1996 and ongoing magmatic eruptions of Popocatépetl: Coupled and fluidized bed events","authors":"Wendy A. McCausland ,&nbsp;Gema V. Caballero-Jimenez ,&nbsp;Enrique Guevara-Ortiz ,&nbsp;Nancy Trujillo-Castrillón ,&nbsp;Carlos M. Valdés-González ,&nbsp;Ángel Gómez-Vázquez ,&nbsp;Hugo Delgado-Granados ,&nbsp;Alejandra Arciniega-Ceballos ,&nbsp;Randall A. White","doi":"10.1016/j.jvolgeores.2024.108208","DOIUrl":"10.1016/j.jvolgeores.2024.108208","url":null,"abstract":"<div><div>We describe three unique types of seismicity at Popocatépetl volcano that accompanied the initial vent-clearing eruptive activity in December 1994 through the eruption of the first two domes in 1996. We identify and describe two types of coupled events, 1) spasmodic burst coupled events, a burst of volcano tectonic (VT) events coupled with a large eruptive explosion (21 December 1994 and 5 March 1996), and 2) explosion-couplet coupled events, a pair of events with a deeper first event and whose second event correlates with a small gas emission or explosion. Explosion-couplets occurred with the onset of magmatic ash dominated eruptions and their properties are very useful for forecasting magmatic eruptions at Popocatépetl volcano. Measurable quantities including the time between the first and second phase, daily numbers of events, and the amplitude ratio between the second and first phase systematically changed as the first two domes approached the surface between March and June 1996. Interevent times decreased from many tens of seconds to a few seconds, while amplitude ratios increased from about 2 to 10 or more. Event numbers increased prior to and during initial dome extrusion. These changes were used to forecast the eruption of the first two domes. We also report on another unusual type of low frequency seismicity that accompanied emissions called fluidized bed events. Fluidized bed events occurred following the initial eruption on 21 December 1994, beginning mid-January 1995, when SO₂ emissions were initially elevated, and the conduit was open. Fluidized bed events began to wane in late March through the end of May 1995 as did SO₂ emissions. Consistent gas, visual and seismic observations by Centro Nacional de Prevención de Desastres (CENAPRED) enabled the direct correlation of the gas, magma, and seismic phenomena.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"455 ","pages":"Article 108208"},"PeriodicalIF":2.4,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improved volcanic SO2 flux records from integrated scanning-DOAS and UV Camera observations.","authors":"Giovanni Lo Bue Trisciuzzi ,&nbsp;Alessandro Aiuppa ,&nbsp;Giuseppe Salerno ,&nbsp;Marcello Bitetto ,&nbsp;Luciano Curcio ,&nbsp;Lorenzo Innocenti ,&nbsp;Giorgio Lacanna ,&nbsp;Joao Pedro Nogueira Lages ,&nbsp;Francesco Maria Lo Forte ,&nbsp;Salvatore Roberto Maugeri ,&nbsp;Filippo Murè ,&nbsp;Paolo Principato ,&nbsp;Maurizio Ripepe ,&nbsp;Angelo Vitale ,&nbsp;Dario Delle Donne","doi":"10.1016/j.jvolgeores.2024.108207","DOIUrl":"10.1016/j.jvolgeores.2024.108207","url":null,"abstract":"<div><div>Volcanic SO₂ flux is a key indicator of magma influx into shallower portions of magmatic plumbing systems, and as such is central to volcano monitoring. However, observations have traditionally been challenged by a variety of technical and methodological caveats and limitations, to overcome which it is required an intercomparison of different observational techniques and, where possible, their integration. Here, we compare ∼9 years (2014 to 2022) of SO₂ flux records at Stromboli obtained through (i) a near-vent (∼500 m) UV Camera system and (ii) a network of DOAS spectrometers scanning the distal (∼2 km) bulk plume. We find a large (133 t/d on average) systematic offset between the SO₂ flux time-series streamed by the two observational techniques, with the flux from the scanning spectrometers being ∼200 % higher on average than UV Camera flux. We propose this mismatch to derive from a combination of (i) SO₂ flux underestimation by the UV Camera, as caused by incomplete coverage of the plume (due to topography of the crater area) and radiative transfer issues in the optically dense, near-vent plume, and (ii) SO₂ flux overestimation by the distal scanning spectrometers', caused by non-ideal (incomplete) atmospheric dilution of source-released gas puffs during atmospheric transport. Our analysis suggests this latter process to be dominant, imparting a positive wind speed dependence and a marked seasonality to the distal scanning spectrometers' fluxes, and causing them to significantly overestimate the source SO₂ fluxes. Finally, we propose a novel integrated SO₂ flux record, based on the combination of UV Camera-derived gas velocities and DOAS-derived SO₂ integrated column amounts (back-calculated at source using an experimentally derived plume dilution function). We expect this SO₂ flux time-series to be less affected by external factors (e.g., meteorological, illumination and volcano topography conditions) than using any of the two techniques alone and hence a better proxy of volcano behaviour. We recommend testing of the integrated UV Camera-scanning-DOAS method at other volcanoes to explore its utility for improved volcanic degassing characterization.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"455 ","pages":"Article 108207"},"PeriodicalIF":2.4,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142534470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Melt generation and magma storage conditions of primitive arc lavas in the Macolod Corridor, southwestern Luzon arc, Philippines","authors":"John Michael Ausejo ,&nbsp;Americus D.C. Perez ,&nbsp;Julius A. Pasco ,&nbsp;Betchaida D. Payot","doi":"10.1016/j.jvolgeores.2024.108206","DOIUrl":"10.1016/j.jvolgeores.2024.108206","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Decoding the origin of primitive arc magmas from petrological, geochemical, and thermobarometric constraints is crucial for understanding their melt generation process and crustal storage conditions. In the Philippine arc setting, primitive basalts have been recognized in the Macolod Corridor, southwestern Luzon arc. The Macolod Corridor is a 30 by 60-km northeast-southwest striking, young rift system that hosts several Quaternary stratovolcanoes including the active Taal Volcano and Mt. Banahaw, lava domes, and ∼ 200 monogenetic centers classified as scoria cones, tuff cones, tuff rings, and maars. This study reports textural, petrological, and geochemical analyses of the Macolod primitive basalts to decipher their petrogenesis and elucidate their pre-eruptive magma storage conditions. We identified at least five distinct primitive lava compositions based on their modal mineralogy: clinopyroxene-olivine basalts, plagioclase-olivine-clinopyroxene basalts, olivine-plagioclase-clinopyroxene basalts, clinopyroxene-plagioclase-olivine basalts, and clinopyroxene-olivine-plagioclase basalts. Clinopyroxene-olivine basalts and clinopyroxene-plagioclase-olivine basalts occur as lapilli and bomb deposits. In contrast, plagioclase-olivine-clinopyroxene-basalts, olivine-plagioclase-clinopyroxene basalts, and clinopyroxene-olivine-plagioclase basalts occur as lapilli and volcanic bombs in monogenetic volcanoes and as basaltic blocky lava flows in small polygenetic volcanoes. Phenocrysts, glomerocrysts, and microphenocrysts assemblages include olivine, clinopyroxene, plagioclase ± spinel in a glassy matrix. The basalts are identified as subalkaline, medium-K, and medium-Fe tholeiitic basalts, based on their bulk-rock geochemistry. Adding 3&lt;strong&gt;–&lt;/strong&gt;4 % equilibrium olivine to the Macolod primitive basalts generates magmas in equilibrium with mantle olivines with Fo&lt;sub&gt;90.68&lt;/sub&gt;&lt;sub&gt;–&lt;/sub&gt;&lt;sub&gt;90.82&lt;/sub&gt; and 0.392&lt;strong&gt;–&lt;/strong&gt;0.395 wt% NiO compositions. Disequilibrium textures exhibited by olivines, clinopyroxenes, and plagioclases suggest that these are products of magma decompression and dissolution processes. Calculated melt based on olivines reveals that these primitive magmas last equilibrated at depths ranging from ∼36&lt;strong&gt;–&lt;/strong&gt;42 km (1.03&lt;strong&gt;–&lt;/strong&gt;1.23 GPa) at 1286°&lt;strong&gt;–&lt;/strong&gt;1318 °C. Application of clinopyroxene-only thermobarometer results indicate clinopyroxene crystallization depths of around 7&lt;strong&gt;–&lt;/strong&gt;16 and 10&lt;strong&gt;–&lt;/strong&gt;19 km for hydrous and anhydrous estimates, respectively. The segregation depths estimated in this study translate to the uppermost mantle until near the Moho boundary whereas the storage depths correspond to prolonged magma storage regions in the upper crust as modeled by existing geophysical data (i.e., seismic travel-time tomography). Combining textural and geochemical results from this study with existing geophysical data provides new insights into the magma plumbi","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"455 ","pages":"Article 108206"},"PeriodicalIF":2.4,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142441434","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}