Pub Date : 2024-11-20DOI: 10.1016/j.jvolgeores.2024.108232
Oliver D. Lamb , Paul A. Jarvis , Geoff Kilgour
The 15 January 2022 eruption of Hunga volcano (Kingdom of Tonga) featured one of the most powerful blasts in recent history, generating atmospheric acoustic phenomena observed around the world. Here we examine seismo-acoustic data of the eruption from across Aotearoa New Zealand, host of the densest network of seismo-acoustic sensors in the south-west Pacific. We find clear evidence for two wavepackets of audible acoustics generated by the eruption propagating north-to-south across Aotearoa New Zealand. Celerities estimated from manually picked arrival times indicate that each wavepacket was likely induced by nonlinear phenomena during the passage of Lamb and Pekeris waves, the latter an atmospheric resonance mode not observed prior to the eruption of Hunga volcano. We also highlight results from array processing across a large scale acoustic network, where we successfully detect and estimate backazimuths for coherent low frequency acoustic waves across a maximum aperture of 11 km. The observations presented here provide a new dataset for developing novel techniques for modelling and monitoring of rare atmospheric acoustic phenomena.
{"title":"Audible and infrasonic waves generated during the 2022 Hunga eruption: Observations from across Aotearoa New Zealand","authors":"Oliver D. Lamb , Paul A. Jarvis , Geoff Kilgour","doi":"10.1016/j.jvolgeores.2024.108232","DOIUrl":"10.1016/j.jvolgeores.2024.108232","url":null,"abstract":"<div><div>The 15 January 2022 eruption of Hunga volcano (Kingdom of Tonga) featured one of the most powerful blasts in recent history, generating atmospheric acoustic phenomena observed around the world. Here we examine seismo-acoustic data of the eruption from across Aotearoa New Zealand, host of the densest network of seismo-acoustic sensors in the south-west Pacific. We find clear evidence for two wavepackets of audible acoustics generated by the eruption propagating north-to-south across Aotearoa New Zealand. Celerities estimated from manually picked arrival times indicate that each wavepacket was likely induced by nonlinear phenomena during the passage of Lamb and Pekeris waves, the latter an atmospheric resonance mode not observed prior to the eruption of Hunga volcano. We also highlight results from array processing across a large scale acoustic network, where we successfully detect and estimate backazimuths for coherent low frequency acoustic waves across a maximum aperture of 11 km. The observations presented here provide a new dataset for developing novel techniques for modelling and monitoring of rare atmospheric acoustic phenomena.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"457 ","pages":"Article 108232"},"PeriodicalIF":2.4,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142720457","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}
Pub Date : 2024-11-19DOI: 10.1016/j.jvolgeores.2024.108236
Marco Calò , Anna Tramelli
Campi Flegrei is one of the largest active calderas exhibiting several episodes of unrest since historical times. These episodes are characterized by numerous earthquakes and significant soil uplifts, often reaching several centimeters or even meters within each cycle. Seismicity in this region rises substantial concern, as it is a primary precursor to potential volcanic eruptions. Additionally, the intense urbanization of the area amplifies the seismic and volcanic risk increasing the population concern. The last unrest phase began in 2006 and is still ongoing. It is accompanied by a large number of earthquakes mainly concentrated beneath the Solfatara-Pisciarelli system, accompanied by the increment of gas emission in Pisciarelli and significant variations in geochemical and geophysical parameters.
In this study we present two classes of seismic models generated using passive methods employing earthquakes recorded from 2005 to November 2023 and continuous ambient noise recorded at 20 stations between 2012 and 2021. These models reveal the existence of high P-wave velocity bodies within the caldera: one onshore, located between the port of Pozzuoli and Solfatara, and another offshore, located a few kilometers south of Pozzuoli. The body beneath Pozzuoli and Solfatara lies at 3.0 km deep, exhibiting high Vp/Vs ratios suggesting it is rich in fluids and possibly contributing to the current unrest. Ambient noise tomography shows that both anomalous bodies are linked to the structures at the edge of the resurgence block forming the central part of the coast of the Pozzuoli Gulf, which is responsible for the uplift of the marine terraces. These findings suggest that the peripheral structures may influence the upward fluid migration, playing a role in the sustaining the ongoing unrest.
{"title":"Evidences of the structures controlling the unrest in Campi Flegrei, Italy; Joint interpretation of ambient noise and local earthquake tomography","authors":"Marco Calò , Anna Tramelli","doi":"10.1016/j.jvolgeores.2024.108236","DOIUrl":"10.1016/j.jvolgeores.2024.108236","url":null,"abstract":"<div><div>Campi Flegrei is one of the largest active calderas exhibiting several episodes of unrest since historical times. These episodes are characterized by numerous earthquakes and significant soil uplifts, often reaching several centimeters or even meters within each cycle. Seismicity in this region rises substantial concern, as it is a primary precursor to potential volcanic eruptions. Additionally, the intense urbanization of the area amplifies the seismic and volcanic risk increasing the population concern. The last unrest phase began in 2006 and is still ongoing. It is accompanied by a large number of earthquakes mainly concentrated beneath the Solfatara-Pisciarelli system, accompanied by the increment of gas emission in Pisciarelli and significant variations in geochemical and geophysical parameters.</div><div>In this study we present two classes of seismic models generated using passive methods employing earthquakes recorded from 2005 to November 2023 and continuous ambient noise recorded at 20 stations between 2012 and 2021. These models reveal the existence of high P-wave velocity bodies within the caldera: one onshore, located between the port of Pozzuoli and Solfatara, and another offshore, located a few kilometers south of Pozzuoli. The body beneath Pozzuoli and Solfatara lies at 3.0 km deep, exhibiting high Vp/Vs ratios suggesting it is rich in fluids and possibly contributing to the current unrest. Ambient noise tomography shows that both anomalous bodies are linked to the structures at the edge of the resurgence block forming the central part of the coast of the Pozzuoli Gulf, which is responsible for the uplift of the marine terraces. These findings suggest that the peripheral structures may influence the upward fluid migration, playing a role in the sustaining the ongoing unrest.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"457 ","pages":"Article 108236"},"PeriodicalIF":2.4,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698260","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}
Pub Date : 2024-11-19DOI: 10.1016/j.jvolgeores.2024.108237
Yingchun Wang , Xiaocheng Zhou , Jiao Tian , Haoxin Jia , Xiaoyi Zhu , Jiang Li , Miao He , Zhaojun Zeng , Yucong Yan , Bingyu Yao , Yuwen Wang , Gaoyuan Xing , Shihan Cui , Liwu Li , Zhongping Li , Chunhui Cao , Lantian Xing
Determining parent magmatic sources of active and dormant volcanoes is crucial for understanding their formation and geodynamic processes. The Tengchong volcanic field (TCV), an intraplate volcanic group located in the southeastern part of the Qinghai–Tibet Plateau, is linked to mantle disturbances through the eastward subduction of the Indian plate. By comprehensive analysis helium and carbon isotopes in hot springs in the TCV, this study revealed that volatile degassing within the TCV predominantly originated from the mantle. Volatile degassing history, coupled with a helium magma aging model, corroborated that the helium of the parent magma was similar to that found in oceanic island basalts, probable sourced from stagnant oceanic slab dehydration above the mantle transition zone, firstly providing compelling geochemical evidence for the upwelling of profound mantle materials. This research not only elucidates the enigmatic geothermal behaviors of intraplate volcanoes but also enhances our understanding of the tectonic dynamics of SE Tibetan Plateau.
{"title":"Spatiotemporal characteristics of hydrothermal volatiles from the Tengchong volcanic field in the southeastern Tibetan Plateau: A probable constraint on the genesis of intraplate volcanism","authors":"Yingchun Wang , Xiaocheng Zhou , Jiao Tian , Haoxin Jia , Xiaoyi Zhu , Jiang Li , Miao He , Zhaojun Zeng , Yucong Yan , Bingyu Yao , Yuwen Wang , Gaoyuan Xing , Shihan Cui , Liwu Li , Zhongping Li , Chunhui Cao , Lantian Xing","doi":"10.1016/j.jvolgeores.2024.108237","DOIUrl":"10.1016/j.jvolgeores.2024.108237","url":null,"abstract":"<div><div>Determining parent magmatic sources of active and dormant volcanoes is crucial for understanding their formation and geodynamic processes. The Tengchong volcanic field (TCV), an intraplate volcanic group located in the southeastern part of the Qinghai–Tibet Plateau, is linked to mantle disturbances through the eastward subduction of the Indian plate. By comprehensive analysis helium and carbon isotopes in hot springs in the TCV, this study revealed that volatile degassing within the TCV predominantly originated from the mantle. Volatile degassing history, coupled with a helium magma aging model, corroborated that the helium of the parent magma was similar to that found in oceanic island basalts, probable sourced from stagnant oceanic slab dehydration above the mantle transition zone, firstly providing compelling geochemical evidence for the upwelling of profound mantle materials. This research not only elucidates the enigmatic geothermal behaviors of intraplate volcanoes but also enhances our understanding of the tectonic dynamics of SE Tibetan Plateau.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"457 ","pages":"Article 108237"},"PeriodicalIF":2.4,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698191","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}
Pub Date : 2024-11-15DOI: 10.1016/j.jvolgeores.2024.108217
D. Skye Kushner , Taryn Lopez , Christoph Kern , Santiago Arellano , Nemesio M. Pérez , José Barrancos
A large source of error in SO2 emission rates derived from mobile Differential Optical Absorption Spectroscopy (DOAS) of volcanic gas plumes is the uncertainty in atmospheric light paths between the sun and the instrument, particularly under non-ideal atmospheric conditions, such as the presence of low clouds. DOAS instruments measure the SO2 column density along the effective light path, so changes to that pathway directly affect the measured SO2 signal. Due to complex radiative transfer mechanisms when a cloud is between the DOAS viewing position and a volcanic plume, measured plumes can appear spatially offset from their true location, a phenomenon informally referred to as “ghost plumes.” In addition to the appearance of ghost plumes, DOAS measurements recorded in non-ideal conditions have poorly characterized errors and are often discarded, limiting the data available to characterize volcanic degassing. In this study we simulate the radiative transfer associated with zenith-facing mobile DOAS traverses using the McArtim radiative transfer model for scenarios when there is a cloud layer between the instrument and the volcanic plume. In total, 217 permutations of atmospheric optical conditions are considered with varying cloud opacities (AOD = 0, 1, 2, 4, 8, 20), plume opacities (AOD = 0, 1, 2, 4, 8), solar zenith angles (SZA = 1°, 30°, 60°), and cloud thicknesses (200, 400, 800 m). We first develop objective criteria for selecting SO2 baseline absorption levels and plume spatial extents. The simulated plume traverses are then integrated to obtain the SO2 cross-sectional burdens which, after multiplication with the wind speed, yield SO2 emission rates. We find large modification in the shape of the modeled cross-sectional burdens even under translucent (low AOD) cloud conditions in our modeled scenarios. Despite modification of the plume shape, the presence of a low cloud layer is typically not a large source of error in the SO2 cross-sectional burden or emission rate obtained from zenith-facing DOAS traverses. We find that all measured cross-sectional burdens simulated using an aerosol-free plume in the above conditions and SZA ≤ 30° are within ±25% of the true value.
通过移动式差分光学吸收光谱（DOAS）对火山气体羽流进行分析得出的二氧化硫排放率的一大误差来源是太阳和仪器之间的大气光路的不确定性，特别是在非理想大气条件下，如存在低云。DOAS 仪器沿有效光路测量二氧化硫柱密度，因此光路的变化会直接影响测量到的二氧化硫信号。当云层位于 DOAS 观测位置和火山羽流之间时，由于复杂的辐射传递机制，测量到的羽流可能会出现与其真实位置的空间偏移，这种现象被非正式地称为 "幽灵羽流"。除了 "幽灵羽流 "的出现，在非理想条件下记录的 DOAS 测量误差也不明显，通常会被丢弃，从而限制了用于描述火山脱气特征的数据。在这项研究中，我们使用 McArtim 辐射传输模型模拟了仪器与火山羽流之间存在云层时，与天顶面移动 DOAS 穿越相关的辐射传输。我们总共考虑了 217 种大气光学条件的变化，云的不透明性（AOD = 0、1、2、4、8、20）、羽流的不透明性（AOD = 0、1、2、4、8）、太阳天顶角（SZA = 1°、30°、60°）和云的厚度（200、400、800 米）各不相同。我们首先制定了选择二氧化硫基线吸收水平和烟羽空间范围的客观标准。然后对模拟的烟羽穿越进行整合，以获得二氧化硫截面负担，在与风速相乘后，得出二氧化硫排放率。我们发现，即使在模拟场景中的半透明云（低 AOD）条件下，模拟截面负担的形状也会发生很大变化。尽管羽流形状会发生改变，但低云层的存在通常不会对从天顶方向的 DOAS 穿越中获得的二氧化硫截面负荷或排放率造成很大误差。我们发现，在上述条件和 SZA ≤ 30° 的情况下，使用无气溶胶羽流模拟的所有测量截面负荷都在真实值的±25%以内。
{"title":"The ghost plume phenomenon and its impact on zenith-facing remote sensing measurements of volcanic SO2 emission rates","authors":"D. Skye Kushner , Taryn Lopez , Christoph Kern , Santiago Arellano , Nemesio M. Pérez , José Barrancos","doi":"10.1016/j.jvolgeores.2024.108217","DOIUrl":"10.1016/j.jvolgeores.2024.108217","url":null,"abstract":"<div><div>A large source of error in SO<sub>2</sub> emission rates derived from mobile Differential Optical Absorption Spectroscopy (DOAS) of volcanic gas plumes is the uncertainty in atmospheric light paths between the sun and the instrument, particularly under non-ideal atmospheric conditions, such as the presence of low clouds. DOAS instruments measure the SO<sub>2</sub> column density along the effective light path, so changes to that pathway directly affect the measured SO<sub>2</sub> signal. Due to complex radiative transfer mechanisms when a cloud is between the DOAS viewing position and a volcanic plume, measured plumes can appear spatially offset from their true location, a phenomenon informally referred to as “ghost plumes.” In addition to the appearance of ghost plumes, DOAS measurements recorded in non-ideal conditions have poorly characterized errors and are often discarded, limiting the data available to characterize volcanic degassing. In this study we simulate the radiative transfer associated with zenith-facing mobile DOAS traverses using the McArtim radiative transfer model for scenarios when there is a cloud layer between the instrument and the volcanic plume. In total, 217 permutations of atmospheric optical conditions are considered with varying cloud opacities (AOD = 0, 1, 2, 4, 8, 20), plume opacities (AOD = 0, 1, 2, 4, 8), solar zenith angles (SZA = 1°, 30°, 60°), and cloud thicknesses (200, 400, 800 m). We first develop objective criteria for selecting SO<sub>2</sub> baseline absorption levels and plume spatial extents. The simulated plume traverses are then integrated to obtain the SO<sub>2</sub> cross-sectional burdens which, after multiplication with the wind speed, yield SO<sub>2</sub> emission rates. We find large modification in the shape of the modeled cross-sectional burdens even under translucent (low AOD) cloud conditions in our modeled scenarios. Despite modification of the plume shape, the presence of a low cloud layer is typically not a large source of error in the SO<sub>2</sub> cross-sectional burden or emission rate obtained from zenith-facing DOAS traverses. We find that all measured cross-sectional burdens simulated using an aerosol-free plume in the above conditions and SZA ≤ 30° are within ±25% of the true value.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"457 ","pages":"Article 108217"},"PeriodicalIF":2.4,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142720542","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}
Pub Date : 2024-11-15DOI: 10.1016/j.jvolgeores.2024.108234
Hongbao Liang , Dan Xu , Jingwei Li
The Changbaishan volcano is recognized as one of China's most potentially dangerous active volcanoes. In response to the unrest event of 2002, GPS technology was utilized to monitor the surface deformation it induced. However, the understanding of the volcano's dynamics and the intricacies of GPS data at the time were limited, which affected the quality of the conclusions. For example, the commencement of GPS observations followed the escalation of seismic activities, leading to the loss of some deformation information. Moreover, observational noise in the GPS coordinate sequences introduced oscillations in the evolution of deformation characteristics. To overcome these limitations, we have developed an advanced GPS data processing methodology. This includes the establishment of a meticulous three-tier control network, the employment of high-precision geophysical models in GAMIT/GLOBK software, the creation of a volcanic regional reference frame, and the formulation of a sophisticated motion model for monitoring stations. With these approaches, we have captured the maximum surface deformation caused by the unrest and have re-evaluated the volume change (25.95× 106 m3/year) of the magma chamber based on Mogi model, yielding results that significantly surpass the mean of previous estimates of 8.58 × 106 m3/year and enhancing our understanding of the magma chamber's dimensions. Additionally, the surface deformation following the unrest displayed a pattern of continuous decay, which is in contrast to the seismic activity that initially rose and then declined, peaking notably after the surface deformation's peak. Considering the geological context of the volcano's formation, we have also provided an extensive dataset of GPS velocity fields. We have preliminarily discussed the possible relationship between the subduction of the Pacific Plate and the unrest in 2002, as well as the recent low-level unrest in 2021, acknowledging that this hypothesis requires further confirmation through stress modeling related to the disturbances. The deformation data resulting from the unrest, as well as the background deformation caused by plate subduction presented in this study, provide essential data constraints for the construction of subsequent stress models.
{"title":"Surface deformation caused by the unrest during 2002–2006 of the Changbaishan volcano in China","authors":"Hongbao Liang , Dan Xu , Jingwei Li","doi":"10.1016/j.jvolgeores.2024.108234","DOIUrl":"10.1016/j.jvolgeores.2024.108234","url":null,"abstract":"<div><div>The Changbaishan volcano is recognized as one of China's most potentially dangerous active volcanoes. In response to the unrest event of 2002, GPS technology was utilized to monitor the surface deformation it induced. However, the understanding of the volcano's dynamics and the intricacies of GPS data at the time were limited, which affected the quality of the conclusions. For example, the commencement of GPS observations followed the escalation of seismic activities, leading to the loss of some deformation information. Moreover, observational noise in the GPS coordinate sequences introduced oscillations in the evolution of deformation characteristics. To overcome these limitations, we have developed an advanced GPS data processing methodology. This includes the establishment of a meticulous three-tier control network, the employment of high-precision geophysical models in GAMIT/GLOBK software, the creation of a volcanic regional reference frame, and the formulation of a sophisticated motion model for monitoring stations. With these approaches, we have captured the maximum surface deformation caused by the unrest and have re-evaluated the volume change (25.95× 10<sup>6</sup> m<sup>3</sup>/year) of the magma chamber based on Mogi model, yielding results that significantly surpass the mean of previous estimates of 8.58 × 10<sup>6</sup> m<sup>3</sup>/year and enhancing our understanding of the magma chamber's dimensions. Additionally, the surface deformation following the unrest displayed a pattern of continuous decay, which is in contrast to the seismic activity that initially rose and then declined, peaking notably after the surface deformation's peak. Considering the geological context of the volcano's formation, we have also provided an extensive dataset of GPS velocity fields. We have preliminarily discussed the possible relationship between the subduction of the Pacific Plate and the unrest in 2002, as well as the recent low-level unrest in 2021, acknowledging that this hypothesis requires further confirmation through stress modeling related to the disturbances. The deformation data resulting from the unrest, as well as the background deformation caused by plate subduction presented in this study, provide essential data constraints for the construction of subsequent stress models.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"457 ","pages":"Article 108234"},"PeriodicalIF":2.4,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698259","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}
Pub Date : 2024-11-13DOI: 10.1016/j.jvolgeores.2024.108216
Nicholas F. Meszaros , Matthew J. Zimmerer , James E. Gardner
Rhyolites that erupted between the Otowi and Tshirege members of the Bandelier Tuff, known as the Valle Toledo Member, were investigated in the Jemez Mountains volcanic field to infer changes in eruptive rate and flux between two caldera-forming eruptions. Our analysis combines high-precision 40Ar/39Ar single-crystal laser-fusion dating of sanidine, matrix glass compositions and mineralogy of pumice, depositional textures, and volumetric estimates of erupted rhyolites to present a revised Valle Toledo Member eruptive chronology that integrates our observations with those of previous studies. With the improved temporal resolution of our high-precision eruption ages (median 2σ uncertainty of ±2.9 ka), the updated Valle Toledo Member eruption chronology consists of at least 42 temporally or mineralogically distinct eruptions that we group into four periods of time based on eruption rate. Within the first 8.1 ± 5.1 kyr (∼1605–1597 ka) that followed the Otowi caldera-forming eruption at 1605.4 ± 2.3 ka, six eruptions are recognized. This suggests an average recurrence interval on the order of 1.4 ± 0.9 kyr. Twenty-seven eruptions occurred during the next 194.4 ± 5.1 kyr (from ∼1597–1403 ka) and the average recurrence interval increased to 7.2 ± 0.2 kyr. Following this second period of slower eruption rate, a previously unrecognized eruption hiatus of up to 162.4 ± 3.1 kyr occurred from 1402.9 ± 2.3 ka to 1240.5 ± 2.1 ka. Resumption of volcanic activity is characterized by a series of at least nine volcanic eruptions during the next 8.6 ± 2.5 kyr, culminating in the eruption of the 400 km3 Tshirege Member of the Bandelier Tuff and formation of Valles caldera at 1231.9 ± 1.3 ka. This last phase of pre-caldera activity has the shortest observed average recurrence interval (1.0 ± 0.3 kyr) and greatest eruptive flux (≥ 0.4 ± 0.2 km3/kyr) that occurred between the two caldera-forming eruptions. We interpret the shifts in eruption rate and flux following the 162.4 ± 3.1 kyr eruption hiatus, in addition to mineralogical changes present in post-hiatus rhyolites, as indicators that the Bandelier system was trending towards another major eruption. The magmatic system may have grown gradually throughout the ca. 162 kyr period of volcanic repose; however, the heightened eruption rate in the ca. 10 kyr before caldera collapse is consistent with relatively rapid growth of the magmatic system before the Tshirege event as previously proposed by other studies. Furthermore, the new dataset is consistent with prior geochronology studies of the region that show the four largest explosive eruptions in the Jemez field were all proceeded by very slow eruptive rates or hiatuses. This demonstrates that sequences of heightened volcanic activity can initiate on rapid geological timescales from states of volcanic quiescence in the Bandelier system.
{"title":"Evolution of eruption rate between two caldera-forming eruptions in the Jemez Mountains volcanic field, New Mexico, USA","authors":"Nicholas F. Meszaros , Matthew J. Zimmerer , James E. Gardner","doi":"10.1016/j.jvolgeores.2024.108216","DOIUrl":"10.1016/j.jvolgeores.2024.108216","url":null,"abstract":"<div><div>Rhyolites that erupted between the Otowi and Tshirege members of the Bandelier Tuff, known as the Valle Toledo Member, were investigated in the Jemez Mountains volcanic field to infer changes in eruptive rate and flux between two caldera-forming eruptions. Our analysis combines high-precision <sup>40</sup>Ar/<sup>39</sup>Ar single-crystal laser-fusion dating of sanidine, matrix glass compositions and mineralogy of pumice, depositional textures, and volumetric estimates of erupted rhyolites to present a revised Valle Toledo Member eruptive chronology that integrates our observations with those of previous studies. With the improved temporal resolution of our high-precision eruption ages (median 2σ uncertainty of ±2.9 ka), the updated Valle Toledo Member eruption chronology consists of at least 42 temporally or mineralogically distinct eruptions that we group into four periods of time based on eruption rate. Within the first 8.1 ± 5.1 kyr (∼1605–1597 ka) that followed the Otowi caldera-forming eruption at 1605.4 ± 2.3 ka, six eruptions are recognized. This suggests an average recurrence interval on the order of 1.4 ± 0.9 kyr. Twenty-seven eruptions occurred during the next 194.4 ± 5.1 kyr (from ∼1597–1403 ka) and the average recurrence interval increased to 7.2 ± 0.2 kyr. Following this second period of slower eruption rate, a previously unrecognized eruption hiatus of up to 162.4 ± 3.1 kyr occurred from 1402.9 ± 2.3 ka to 1240.5 ± 2.1 ka. Resumption of volcanic activity is characterized by a series of at least nine volcanic eruptions during the next 8.6 ± 2.5 kyr, culminating in the eruption of the 400 km<sup>3</sup> Tshirege Member of the Bandelier Tuff and formation of Valles caldera at 1231.9 ± 1.3 ka. This last phase of pre-caldera activity has the shortest observed average recurrence interval (1.0 ± 0.3 kyr) and greatest eruptive flux (≥ 0.4 ± 0.2 km<sup>3</sup>/kyr) that occurred between the two caldera-forming eruptions. We interpret the shifts in eruption rate and flux following the 162.4 ± 3.1 kyr eruption hiatus, in addition to mineralogical changes present in post-hiatus rhyolites, as indicators that the Bandelier system was trending towards another major eruption. The magmatic system may have grown gradually throughout the ca. 162 kyr period of volcanic repose; however, the heightened eruption rate in the ca. 10 kyr before caldera collapse is consistent with relatively rapid growth of the magmatic system before the Tshirege event as previously proposed by other studies. Furthermore, the new dataset is consistent with prior geochronology studies of the region that show the four largest explosive eruptions in the Jemez field were all proceeded by very slow eruptive rates or hiatuses. This demonstrates that sequences of heightened volcanic activity can initiate on rapid geological timescales from states of volcanic quiescence in the Bandelier system.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"457 ","pages":"Article 108216"},"PeriodicalIF":2.4,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698257","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}
Pub Date : 2024-11-12DOI: 10.1016/j.jvolgeores.2024.108233
Ivan Koulakov , Evgeny Ilyich Gordeev , Ilyas Abkadyrov , Olga Bergal-Kuvikas , Danila Chebrov
Iturup is the largest island of the Kuril Arc with more than 20 Holocene volcanoes of which 9 considered active. Here we investigate the central part of the island where we deployed in 2022–2023 a portable network of 12 seismic stations. The data of this network together with several permanent stations in surrounding islands were used to identify almost 300 events and to perform seismic tomography based on the picked arrival times of the P and S seismic waves. A challenging problem was that most of the events were located outside the network, and we performed careful analysis to examine the actual capacity of inversion with such data to recover seismic velocity structures below the network. In the resulting model, we found a dominating high-velocity anomaly below the central part of the study area, which is bounded by zones of low velocities and high Vp/Vs ratio collocated with two active volcano complexes (Chirip to the north and Ivan Grozny to the south). Below the third volcano, Baransky, we observe a change of the Vp/Vs ratio from high at large depths to low at shallow depth, indicating the process of degassing, which is supported by strong fumarolic activity and hydrothermal manifestations around this volcano. At depths of more than 20 km, the feeding paths from Baransky and Ivan Grozny volcanoes seem to be connected in one anomaly representing a common magma source below the center of the island. This seems to be a common feature observed below several volcanic islands, such as Tenerife and El Hierro, where the high-velocity rigid core in a central part is surrounded by low-velocity flows associated with recent volcanic manifestations.
{"title":"Feeding system beneath active volcanoes in central part of Iturup Island (Kuril Arc) inferred from local earthquake tomography","authors":"Ivan Koulakov , Evgeny Ilyich Gordeev , Ilyas Abkadyrov , Olga Bergal-Kuvikas , Danila Chebrov","doi":"10.1016/j.jvolgeores.2024.108233","DOIUrl":"10.1016/j.jvolgeores.2024.108233","url":null,"abstract":"<div><div>Iturup is the largest island of the Kuril Arc with more than 20 Holocene volcanoes of which 9 considered active. Here we investigate the central part of the island where we deployed in 2022–2023 a portable network of 12 seismic stations. The data of this network together with several permanent stations in surrounding islands were used to identify almost 300 events and to perform seismic tomography based on the picked arrival times of the P and S seismic waves. A challenging problem was that most of the events were located outside the network, and we performed careful analysis to examine the actual capacity of inversion with such data to recover seismic velocity structures below the network. In the resulting model, we found a dominating high-velocity anomaly below the central part of the study area, which is bounded by zones of low velocities and high Vp/Vs ratio collocated with two active volcano complexes (Chirip to the north and Ivan Grozny to the south). Below the third volcano, Baransky, we observe a change of the Vp/Vs ratio from high at large depths to low at shallow depth, indicating the process of degassing, which is supported by strong fumarolic activity and hydrothermal manifestations around this volcano. At depths of more than 20 km, the feeding paths from Baransky and Ivan Grozny volcanoes seem to be connected in one anomaly representing a common magma source below the center of the island. This seems to be a common feature observed below several volcanic islands, such as Tenerife and El Hierro, where the high-velocity rigid core in a central part is surrounded by low-velocity flows associated with recent volcanic manifestations.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"456 ","pages":"Article 108233"},"PeriodicalIF":2.4,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652527","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}
Pub Date : 2024-11-08DOI: 10.1016/j.jvolgeores.2024.108218
Wade L. Aubin , James E. Gardner
We conducted a set of high-temperature decompression experiments to constrain the mechanisms of heterogeneous bubble nucleation in high-silica rhyolitic melt that contained 4.6–4.8 wt% H2O. The melt was seeded with two different size fractions of magnetite crystals: 1–2 μm crystals and large crystals of 32–135 μm (long axis). The number density of bubbles (BND) that nucleated on the small crystals was found to increase from 106.5 to 108.7 cm−3 as H2O increasingly supersaturated (ΔP) in the melt from 3 to 23 MPa. At ΔP >23 MPs, however, the number of bubbles nucleated equals the number of small magnetite and no more nucleated with increased ΔP. At the same conditions, the number of bubbles that nucleated on the large crystals increases, from <1 bubble per crystal at ΔP = 3 MPa to 14 ± 4 bubbles per crystal at 58 MPa. We thus find that ΔP has a significant influence on the mechanisms of heterogenous nucleation, but the observed increases in BND are much greater than would be predicted solely from the increase in ΔP. The discrepancy can be reconciled if there are different sites on the crystals that become activated at greater ΔP, leading to greater numbers of bubbles nucleating. The cumulative BND nucleated on small crystals, however, is capped by the number of crystals present. The BND values generated at ΔP >23 MPa in our experiments overlap with those found in ∼80 % of naturally occurring pumice. Assuming our experiments are representative of natural pumice, this suggests that explosively erupted magmas either become significantly volatile supersaturated before heterogeneously nucleating bubbles, or that the number of nucleation sites in natural magmas greatly exceed 109 cm−3.
{"title":"The influence of FeTi oxide microlites on bubble nucleation in rhyolitic melts","authors":"Wade L. Aubin , James E. Gardner","doi":"10.1016/j.jvolgeores.2024.108218","DOIUrl":"10.1016/j.jvolgeores.2024.108218","url":null,"abstract":"<div><div>We conducted a set of high-temperature decompression experiments to constrain the mechanisms of heterogeneous bubble nucleation in high-silica rhyolitic melt that contained 4.6–4.8 wt% H<sub>2</sub>O. The melt was seeded with two different size fractions of magnetite crystals: 1–2 μm crystals and large crystals of 32–135 μm (long axis). The number density of bubbles (BND) that nucleated on the small crystals was found to increase from 10<sup>6.5</sup> to 10<sup>8.7</sup> cm<sup>−3</sup> as H<sub>2</sub>O increasingly supersaturated (ΔP) in the melt from 3 to 23 MPa. At ΔP >23 MPs, however, the number of bubbles nucleated equals the number of small magnetite and no more nucleated with increased ΔP. At the same conditions, the number of bubbles that nucleated on the large crystals increases, from <1 bubble per crystal at ΔP = 3 MPa to 14 ± 4 bubbles per crystal at 58 MPa. We thus find that ΔP has a significant influence on the mechanisms of heterogenous nucleation, but the observed increases in BND are much greater than would be predicted solely from the increase in ΔP. The discrepancy can be reconciled if there are different sites on the crystals that become activated at greater ΔP, leading to greater numbers of bubbles nucleating. The cumulative BND nucleated on small crystals, however, is capped by the number of crystals present. The BND values generated at ΔP >23 MPa in our experiments overlap with those found in ∼80 % of naturally occurring pumice. Assuming our experiments are representative of natural pumice, this suggests that explosively erupted magmas either become significantly volatile supersaturated before heterogeneously nucleating bubbles, or that the number of nucleation sites in natural magmas greatly exceed 10<sup>9</sup> cm<sup>−3</sup>.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"456 ","pages":"Article 108218"},"PeriodicalIF":2.4,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652528","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}
Pub Date : 2024-11-03DOI: 10.1016/j.jvolgeores.2024.108220
Amir Eskandari , Sadraddin Amini , Behnam Sadeghi
The Damavand stratovolcano (N Iran) consists mainly of lavas with trachyandesite-trachyte composition, and subordinate pyroclastic deposits. The intensity of explosive eruptions and the volume of pyroclastic deposits have increased over time, which may be related to increasing viscosity due to the development of crystal-rich magmas. This research integrates microanalytical and quantitative textural measurements to understand the textural evolutions from the old to the young lavas and their relationships with the physical processes occurred in the plumbing system. Age-constrained samples from the lavas were analyzed using crystal size distribution (CSD), the newly proposed multifractal analysis, including the Number-Length of crystals (N-LoC) and the Number-Area of crystals (N-AoC), along with mineral chemistry. Three to five populations of feldspars can be identified, which have undergone evolution and coarsening over time. We propose a textural development sequence established at mid to shallow crustal levels, involving several physicochemical processes, such as cycles of polybaric differentiation and episodic magma recharge into the crystal-rich magma chambers. This, in turn, caused disaggregation of crystal mushes and textural coarsening due to crystal aggregation and temperature cycling. The increasing population of microphenocrysts in younger lavas may be linked to pulsating groundmass crystallization resulting from degassing at a newly formed shallow chamber (0.5–1 kbar) beneath the young cone. The final stages of crystallization occurred during multi-step decompression in the conduits. The comparison of age data from lava samples and their stratigraphic positions suggests that triggering groundmass crystallization might have caused shifts in eruptive behavior.
{"title":"The dynamic of magmatic system and volcano hazard implications of the Damavand volcano (N. Iran) inferred from the textural data","authors":"Amir Eskandari , Sadraddin Amini , Behnam Sadeghi","doi":"10.1016/j.jvolgeores.2024.108220","DOIUrl":"10.1016/j.jvolgeores.2024.108220","url":null,"abstract":"<div><div>The Damavand stratovolcano (N Iran) consists mainly of lavas with trachyandesite-trachyte composition, and subordinate pyroclastic deposits. The intensity of explosive eruptions and the volume of pyroclastic deposits have increased over time, which may be related to increasing viscosity due to the development of crystal-rich magmas. This research integrates microanalytical and quantitative textural measurements to understand the textural evolutions from the old to the young lavas and their relationships with the physical processes occurred in the plumbing system. Age-constrained samples from the lavas were analyzed using crystal size distribution (CSD), the newly proposed multifractal analysis, including the Number-Length of crystals (N-LoC) and the Number-Area of crystals (N-AoC), along with mineral chemistry. Three to five populations of feldspars can be identified, which have undergone evolution and coarsening over time. We propose a textural development sequence established at mid to shallow crustal levels, involving several physicochemical processes, such as cycles of polybaric differentiation and episodic magma recharge into the crystal-rich magma chambers. This, in turn, caused disaggregation of crystal mushes and textural coarsening due to crystal aggregation and temperature cycling. The increasing population of microphenocrysts in younger lavas may be linked to pulsating groundmass crystallization resulting from degassing at a newly formed shallow chamber (0.5–1 kbar) beneath the young cone. The final stages of crystallization occurred during multi-step decompression in the conduits. The comparison of age data from lava samples and their stratigraphic positions suggests that triggering groundmass crystallization might have caused shifts in eruptive behavior.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"456 ","pages":"Article 108220"},"PeriodicalIF":2.4,"publicationDate":"2024-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652529","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}
Pub Date : 2024-11-02DOI: 10.1016/j.jvolgeores.2024.108219
Diletta Frascerra , Bruno Scaillet , Joan Andújar , Clive Oppenheimer , Stéphane Scaillet , Joan Martí , Ramón Casillas , Carmen López
We performed experiments to constrain the effects of sulphur and oxygen fugacities on magma chamber and outgassing conditions of the La Palma 2021 eruption. Based on a series of controlled experiments on basanitic products carried out at 1040 °C and 200 MPa, we show that sulphur addition affects the stabilities of amphibole and olivine, in particular at high fO2 and elevated S contents which together inhibit amphibole crystallization. We also show that the overriding control on S systematics is oxygen fugacity, with melts capable of dissolving from 1000 up to 8000 ppm S, depending on fO2. Increasing the bulk S content increases the S content of the silicate melt up to ∼2000 ppm for fO2 < NNO + 2, and 7000–8000 ppm at higher fO2. Further increase in dissolved S is prevented by the buffering effects of either sulphide at low fO2 or anhydrite at high fO2. Modelling shows that the observed CO2/SO2 and H2O/SO2 ratios of volcanic gas emissions during the eruption imply a pre-existing >5 wt% exsolved fluid in the reservoir, with fS2 at ∼0.1 MPa at fO2 above NNO. Our work confirms that basaltic magmas may coexist with a significant amount of excess fluid which in turn holds an important part of the sulphur budget emitted to the atmosphere.
我们进行了实验，以确定硫和氧的富集度对拉帕尔马 2021 火山喷发的岩浆室和排气条件的影响。基于在 1040 °C 和 200 MPa 条件下对玄武岩产物进行的一系列受控实验，我们发现硫的添加会影响闪石和橄榄石的稳定性，尤其是在高 fO2 和 S 含量升高的情况下，硫的添加会共同抑制闪石的结晶。我们还表明，对硫系统学的最主要控制因素是逸氧性，根据 fO2 的不同，熔体能够溶解 1000 至 8000 ppm 的硫。在 fO2 < NNO + 2 条件下，增加体积 S 含量可使硅酸盐熔体中的 S 含量达到 ∼ 2000 ppm，而在更高的 fO2 条件下，则可达到 7000-8000 ppm。在低 fO2 条件下，硫化物的缓冲作用阻止了溶解 S 的进一步增加；在高 fO2 条件下，无水石膏的缓冲作用阻止了溶解 S 的进一步增加。建模表明，在喷发过程中观测到的火山气体排放的 CO2/SO2 和 H2O/SO2 比率意味着储层中预先存在 5 wt%的外溶解流体，当 fO2 高于 NNO 时，fS2 为 0.1 MPa。我们的研究证实，玄武质岩浆可能与大量过剩流体共存，而过剩流体又是排放到大气中的硫的重要来源。
{"title":"Experimental constraints on the behaviour of sulphur in the 2021 Cumbre Vieja (La Palma) basanite","authors":"Diletta Frascerra , Bruno Scaillet , Joan Andújar , Clive Oppenheimer , Stéphane Scaillet , Joan Martí , Ramón Casillas , Carmen López","doi":"10.1016/j.jvolgeores.2024.108219","DOIUrl":"10.1016/j.jvolgeores.2024.108219","url":null,"abstract":"<div><div>We performed experiments to constrain the effects of sulphur and oxygen fugacities on magma chamber and outgassing conditions of the La Palma 2021 eruption. Based on a series of controlled experiments on basanitic products carried out at 1040 °C and 200 MPa, we show that sulphur addition affects the stabilities of amphibole and olivine, in particular at high <em>f</em>O<sub>2</sub> and elevated S contents which together inhibit amphibole crystallization. We also show that the overriding control on S systematics is oxygen fugacity, with melts capable of dissolving from 1000 up to 8000 ppm S, depending on <em>f</em>O<sub>2</sub>. Increasing the bulk S content increases the S content of the silicate melt up to ∼2000 ppm for <em>f</em>O<sub>2</sub> < NNO + 2, and 7000–8000 ppm at higher <em>f</em>O<sub>2</sub>. Further increase in dissolved S is prevented by the buffering effects of either sulphide at low <em>f</em>O<sub>2</sub> or anhydrite at high <em>f</em>O<sub>2</sub>. Modelling shows that the observed CO<sub>2</sub>/SO<sub>2</sub> and H<sub>2</sub>O/SO<sub>2</sub> ratios of volcanic gas emissions during the eruption imply a pre-existing >5 wt% exsolved fluid in the reservoir, with <em>f</em>S<sub>2</sub> at ∼0.1 MPa at <em>f</em>O<sub>2</sub> above NNO. Our work confirms that basaltic magmas may coexist with a significant amount of excess fluid which in turn holds an important part of the sulphur budget emitted to the atmosphere.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"456 ","pages":"Article 108219"},"PeriodicalIF":2.4,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142652530","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}
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