Pub Date : 2025-11-01DOI: 10.1016/j.jvolgeores.2025.108482
P. Muanza , I. Jónsdóttir , T. Thórdarson , G. Einarsson , S. Kristinsson
This study investigates geothermal surface activity across four of the six recognized geothermal systems on the Reykjanes Peninsula in southwest Iceland Reykjanes, Krýsuvík, Miðdalur, and Grændalur using satellite-derived Land Surface Temperature (LST) data from Landsat 8 and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) spanning 2016 to 2023. These sites were selected to represent diverse geothermal behaviors and to maximize temporal data availability under cloud-free conditions. Thermal imagery was acquired from consistent seasonal windows each year to reduce the effects of atmospheric and solar variability. The temporal and spatial evolution of thermal anomalies was analyzed to monitor surface-level geothermal changes, with anomalies defined relative to site-specific thermal baselines. In addition, Moderate Resolution Imaging Spectroradiometer (MODIS) data and ground-based temperature measurements including drone thermal imagery were used at selected sites to validate the satellite-derived LST, enhancing the overall reliability of the findings. Results show heterogeneous thermal responses across the four fields: Reykjanes exhibits persistent LST anomalies potentially linked to shallow magmatic inputs and anthropogenic geothermal operations; Krýsuvík shows episodic thermal peaks coinciding with recent periods of regional volcanic unrest; while Miðdalur and Grændalur display gradually declining thermal signatures and shrinking anomaly extents. These patterns are interpreted as indicative of varying geothermal dynamics and system maturity. The study demonstrates the effectiveness of integrating multi-sensor remote sensing with field validation for long-term geothermal monitoring in tectonically active regions and highlights the importance of interannual consistency and baseline referencing in detecting subtle geothermal changes.
{"title":"Remote sensing of surface thermal anomalies on the Reykjanes Peninsula, SW-Iceland from 2016 to 2023, preceding and coinciding with recent volcanic unrest","authors":"P. Muanza , I. Jónsdóttir , T. Thórdarson , G. Einarsson , S. Kristinsson","doi":"10.1016/j.jvolgeores.2025.108482","DOIUrl":"10.1016/j.jvolgeores.2025.108482","url":null,"abstract":"<div><div>This study investigates geothermal surface activity across four of the six recognized geothermal systems on the Reykjanes Peninsula in southwest Iceland Reykjanes, Krýsuvík, Miðdalur, and Grændalur using satellite-derived Land Surface Temperature (LST) data from Landsat 8 and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) spanning 2016 to 2023. These sites were selected to represent diverse geothermal behaviors and to maximize temporal data availability under cloud-free conditions. Thermal imagery was acquired from consistent seasonal windows each year to reduce the effects of atmospheric and solar variability. The temporal and spatial evolution of thermal anomalies was analyzed to monitor surface-level geothermal changes, with anomalies defined relative to site-specific thermal baselines. In addition, Moderate Resolution Imaging Spectroradiometer (MODIS) data and ground-based temperature measurements including drone thermal imagery were used at selected sites to validate the satellite-derived LST, enhancing the overall reliability of the findings. Results show heterogeneous thermal responses across the four fields: Reykjanes exhibits persistent LST anomalies potentially linked to shallow magmatic inputs and anthropogenic geothermal operations; Krýsuvík shows episodic thermal peaks coinciding with recent periods of regional volcanic unrest; while Miðdalur and Grændalur display gradually declining thermal signatures and shrinking anomaly extents. These patterns are interpreted as indicative of varying geothermal dynamics and system maturity. The study demonstrates the effectiveness of integrating multi-sensor remote sensing with field validation for long-term geothermal monitoring in tectonically active regions and highlights the importance of interannual consistency and baseline referencing in detecting subtle geothermal changes.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"469 ","pages":"Article 108482"},"PeriodicalIF":2.3,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145468681","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 : 2025-10-31DOI: 10.1016/j.jvolgeores.2025.108481
Alex S. Gold , Madisen Snowden , James D. Muirhead , Pilar Villamor , Genevieve L. Coffey , Colin J.N. Wilson , Regine Morgenstern
Intra-arc rifts are regions of extensional tectonics and magmatic processes, which can interact and lead to both earthquakes and volcanic activity. We examine the temporal and spatial relationships between the ∼35 km3 (magma), caldera-forming, 232 ± 10 CE eruption from Taupō volcano of the Taupō Volcanic Zone and slip on the adjacent Whakaipō Fault. The spatio-temporal distribution of fault throw is examined through paleoseismic trenching coupled with remote and field-based analyses of the fault scarp and deformed post-eruptive paleoshorelines intersected by this structure. Along the Whakaipō Fault, throw increases towards the volcano, reflecting the role of Taupō volcano in localising fault strain. Paleoseismic trenching exposes an un-degraded paleoscarp with a ∼50° slope draped by 232 CE fall deposits, implying that fault slip occurred no more than days to months prior to the eruption. Analysis of fault and paleoshoreline displacements at Whakaipō Bay on the northern Lake Taupō shoreline suggest that two main phases of Whakaipō Fault slip occurred after the eruption: (1) an ‘aftermath’ phase, occurring over a ∼20-year period after the eruption, during which 10 ± 1.2 m of throw was accrued locally on the fault; and (2) a ‘longer-term’ phase through to the present day, during which 2.8 ± 0.3 m of fault throw has accrued. Faulting during the aftermath phase is estimated to account for ∼78% of the total extension accommodated locally (adjacent to the caldera) on the Whakaipō Fault since the 232 CE eruption. Our observations suggest that caldera-forming eruptions in the TVZ can be associated with complex, volcano-tectonic (i.e., rifting) sequences that feature both pre-eruptive and highly localised, post-eruptive, decametre-scale displacement on caldera-adjacent rift faults.
{"title":"Large-scale rift-related faulting linked to a caldera-forming eruption: A case study from Taupō, New Zealand","authors":"Alex S. Gold , Madisen Snowden , James D. Muirhead , Pilar Villamor , Genevieve L. Coffey , Colin J.N. Wilson , Regine Morgenstern","doi":"10.1016/j.jvolgeores.2025.108481","DOIUrl":"10.1016/j.jvolgeores.2025.108481","url":null,"abstract":"<div><div>Intra-arc rifts are regions of extensional tectonics and magmatic processes, which can interact and lead to both earthquakes and volcanic activity. We examine the temporal and spatial relationships between the ∼35 km<sup>3</sup> (magma), caldera-forming, 232 ± 10 CE eruption from Taupō volcano of the Taupō Volcanic Zone and slip on the adjacent Whakaipō Fault. The spatio-temporal distribution of fault throw is examined through paleoseismic trenching coupled with remote and field-based analyses of the fault scarp and deformed post-eruptive paleoshorelines intersected by this structure. Along the Whakaipō Fault, throw increases towards the volcano, reflecting the role of Taupō volcano in localising fault strain. Paleoseismic trenching exposes an un-degraded paleoscarp with a ∼50° slope draped by 232 CE fall deposits, implying that fault slip occurred no more than days to months prior to the eruption. Analysis of fault and paleoshoreline displacements at Whakaipō Bay on the northern Lake Taupō shoreline suggest that two main phases of Whakaipō Fault slip occurred after the eruption: (1) an ‘aftermath’ phase, occurring over a ∼20-year period after the eruption, during which 10 ± 1.2 m of throw was accrued locally on the fault; and (2) a ‘longer-term’ phase through to the present day, during which 2.8 ± 0.3 m of fault throw has accrued. Faulting during the aftermath phase is estimated to account for ∼78% of the total extension accommodated locally (adjacent to the caldera) on the Whakaipō Fault since the 232 CE eruption. Our observations suggest that caldera-forming eruptions in the TVZ can be associated with complex, volcano-tectonic (i.e., rifting) sequences that feature both pre-eruptive and highly localised, post-eruptive, decametre-scale displacement on caldera-adjacent rift faults.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"469 ","pages":"Article 108481"},"PeriodicalIF":2.3,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145520679","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 : 2025-10-30DOI: 10.1016/j.jvolgeores.2025.108484
A. Sork , P. Kreit , D. Banerjee , M. Sellier , B. Kennedy , L. Watson , R. Fitzgerald , F. McIntyre , K. Tsunematsu
Volcanic ballistic projectiles (VBPs) are a dangerous near-vent hazard. Physics-based models are often used to estimate potential impact locations to help reduce risk to nearby people and environment. Drag is an essential model component, but many VBPs, especially molten VBPs (bombs), are irregular in shape and their drag behaviour has not previously been quantified.
We measure 3D-printed models of in-flight Strombolian bomb shapes in a wind tunnel to quantify drag effects in terms of drag coefficient (CD) and Reynolds number (Re). Tests were performed on static models across increasingly oblique angles to the air flow, and on dynamically rotating models across increasing spin frequencies. The model size and air speeds tested here correspond with Re values 9.3 × 104 to 1.2 × 106, encompassing the laminar-turbulent flow transition into the supercritical Re regime (which occurs at ∼2.5 × 105 for spheres).
We find rounded and bilobate shapes have distinctly different drag behaviour. The CD of bilobate shapes varies significantly with changes in orientation (0.29-0.41 head-on, 0.64-0.88 broadside). The CD of rounded shapes varies little with changes in orientation (0.2-0.4 head-on, 0.33-0.44 broadside), lower than the range for bilobate shapes at both head-on and broadside. The average CD of a rotating model approaches its broadside static CD. We compare results to in-flight observations where spin is commonly observed and conclude that the broadside CD is most applicable for use in scenario modelling. For Strombolian VBPs at supercritical Reynolds number, we therefore recommend a CD range of 0.33-0.88 and propose a new methodology for physics-based models which accounts for relationships between size, shape, Reynolds number, and CD.
{"title":"Empirical drag coefficients for in-flight volcanic bombs: A novel application of aerospace techniques to volcanic hazards","authors":"A. Sork , P. Kreit , D. Banerjee , M. Sellier , B. Kennedy , L. Watson , R. Fitzgerald , F. McIntyre , K. Tsunematsu","doi":"10.1016/j.jvolgeores.2025.108484","DOIUrl":"10.1016/j.jvolgeores.2025.108484","url":null,"abstract":"<div><div>Volcanic ballistic projectiles (VBPs) are a dangerous near-vent hazard. Physics-based models are often used to estimate potential impact locations to help reduce risk to nearby people and environment. Drag is an essential model component, but many VBPs, especially molten VBPs (bombs), are irregular in shape and their drag behaviour has not previously been quantified.</div><div>We measure 3D-printed models of in-flight Strombolian bomb shapes in a wind tunnel to quantify drag effects in terms of drag coefficient (C<sub>D</sub>) and Reynolds number (<em>Re</em>). Tests were performed on static models across increasingly oblique angles to the air flow, and on dynamically rotating models across increasing spin frequencies. The model size and air speeds tested here correspond with <em>Re</em> values 9.3 × 10<sup>4</sup> to 1.2 × 10<sup>6</sup>, encompassing the laminar-turbulent flow transition into the supercritical <em>Re</em> regime (which occurs at ∼2.5 × 10<sup>5</sup> for spheres).</div><div>We find rounded and bilobate shapes have distinctly different drag behaviour. The C<sub>D</sub> of bilobate shapes varies significantly with changes in orientation (0.29-0.41 head-on, 0.64-0.88 broadside). The C<sub>D</sub> of rounded shapes varies little with changes in orientation (0.2-0.4 head-on, 0.33-0.44 broadside), lower than the range for bilobate shapes at both head-on and broadside. The average C<sub>D</sub> of a rotating model approaches its broadside static C<sub>D</sub>. We compare results to in-flight observations where spin is commonly observed and conclude that the broadside C<sub>D</sub> is most applicable for use in scenario modelling. For Strombolian VBPs at supercritical Reynolds number, we therefore recommend a C<sub>D</sub> range of 0.33-0.88 and propose a new methodology for physics-based models which accounts for relationships between size, shape, Reynolds number, and C<sub>D</sub>.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"469 ","pages":"Article 108484"},"PeriodicalIF":2.3,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145428793","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 : 2025-10-25DOI: 10.1016/j.jvolgeores.2025.108480
K.M. Williams , A. Geyer , C. Annen , J. Kavanagh
Sill geometry and magma flow indicators preserved within fossil sills are used to determine magma source locations, understand economic potential of magmatic ore deposits, and forecast potential volcanic eruption sites. However, existing models struggle to incorporate complex flow dynamics and quantify flow variability, thus inhibiting their potential to explain spatially variable magma flow within sills spanning up to hundreds of kilometres. We present results of new 2D finite element numerical simulations coupling fluid and thermal dynamics within a dyke-fed sill using a multiphysics approach. As magma enters the model sill from below via one (or several) feeding dyke(s), magma jets of variable height develop within the sill depending on dyke thickness and inlet velocity. Low-velocity zones occur near the feeding dyke(s), with recirculation present between multiple feeding dyke(s) when they are present. These findings demonstrate the significant impact that intrusion geometry has on the magma flow dynamics within the sill, and we postulate that the presence of magma jets at the dyke-to-sill transition may be one source of sill lobes. They suggest random crystal orientations could be expected close to feeder dykes (low-velocity recirculating flow and rapid solidification), but where strain rates are high crystal alignment may still occur. These results potentially explain complex magma flow as interpreted from field observations and petrographic analysis of sill. Our results show that incorporating intrusion geometries, flow dynamics and thermal processes into models is crucial for bridging the gap between field observations and the underlying processes that govern natural systems.
{"title":"Modelling magma flow within dyke-fed sill geometries: A coupled thermal and fluid dynamics approach","authors":"K.M. Williams , A. Geyer , C. Annen , J. Kavanagh","doi":"10.1016/j.jvolgeores.2025.108480","DOIUrl":"10.1016/j.jvolgeores.2025.108480","url":null,"abstract":"<div><div>Sill geometry and magma flow indicators preserved within fossil sills are used to determine magma source locations, understand economic potential of magmatic ore deposits, and forecast potential volcanic eruption sites. However, existing models struggle to incorporate complex flow dynamics and quantify flow variability, thus inhibiting their potential to explain spatially variable magma flow within sills spanning up to hundreds of kilometres. We present results of new 2D finite element numerical simulations coupling fluid and thermal dynamics within a dyke-fed sill using a multiphysics approach. As magma enters the model sill from below via one (or several) feeding dyke(s), magma jets of variable height develop within the sill depending on dyke thickness and inlet velocity. Low-velocity zones occur near the feeding dyke(s), with recirculation present between multiple feeding dyke(s) when they are present. These findings demonstrate the significant impact that intrusion geometry has on the magma flow dynamics within the sill, and we postulate that the presence of magma jets at the dyke-to-sill transition may be one source of sill lobes. They suggest random crystal orientations could be expected close to feeder dykes (low-velocity recirculating flow and rapid solidification), but where strain rates are high crystal alignment may still occur. These results potentially explain complex magma flow as interpreted from field observations and petrographic analysis of sill. Our results show that incorporating intrusion geometries, flow dynamics and thermal processes into models is crucial for bridging the gap between field observations and the underlying processes that govern natural systems.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"469 ","pages":"Article 108480"},"PeriodicalIF":2.3,"publicationDate":"2025-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145520729","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 : 2025-10-24DOI: 10.1016/j.jvolgeores.2025.108477
A.A. Shakirova, V.A. Saltykov
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 7–273 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.
{"title":"Mosaic nature of seismicity patterns associated with eruptions of the Klyuchevskoy Volcano (Kamchatka, Russia)","authors":"A.A. Shakirova, 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":"2025-10-24","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}
Pub Date : 2025-10-23DOI: 10.1016/j.jvolgeores.2025.108479
Stefano Mannini , James Hollingsworth , Nicolas Oestreicher , Joël Ruch
The Kīlauea volcano is affected by flank instability related to recurrent volcano-tectonic events and large earthquakes. Yet, the connection between fracture zones and large recurrent earthquakes still remains poorly constrained, mainly because previous geodetic studies provided only sparse point measurements of coseismic deformation. Here we use optical image correlation of historical aerial photographs to analyze the ground displacement associated with the 1975 Kalapana earthquake (Mw 7.7). This approach allows us to reconstruct the spatially continuous distribution of coseismic deformation along the Hilina fault system, including areas that were poorly documented in earlier studies. Results show up to three meters of horizontal surface displacement along the 13 km long Hilina fault system. We observed that the entire main fault was reactivated during this event, with a westward increase of the displacement away from the earthquake epicenter. Our results indicate that the south flank of the volcano is strongly influenced by gravitational processes, with the Hilina fault likely serving as a boundary of a massive slump structure. Despite limitations due to the heterogeneity of the aerial photo acquisitions, this study provides the first detailed, continuous view of coseismic deformation along the Hilina faults during the Kalapana earthquake. Our results highlight the value of archival aerial imagery for constraining fault kinematics and flank dynamics during major historical earthquakes. Moreover, this work provides a new basis for future investigations of the deeper geometry of the Kīlauea volcano's south flank.
kk - lauea火山受火山构造事件和大地震的影响。然而，断裂带与大地震之间的联系仍然很不明确，主要是因为以前的大地测量研究只提供了稀疏的同震变形点测量。在这里，我们使用历史航空照片的光学图像相关性来分析与1975年Kalapana地震（Mw 7.7）相关的地面位移。这种方法使我们能够重建沿Hilina断层系统的同震变形的空间连续分布，包括在早期研究中记录较少的区域。结果显示，沿13公里长的Hilina断裂系统，水平地表位移达3米。我们观察到，整个主断层在这次地震中被重新激活，远离震中的位移向西增加。我们的研究结果表明，火山南侧受到重力作用的强烈影响，Hilina断裂可能是一个巨大滑塌构造的边界。尽管由于航空照片采集的异质性而受到限制，但本研究提供了卡拉帕纳地震期间沿Hilina断层的同震形变的第一个详细的连续视图。我们的研究结果强调了档案航空图像在历史大地震期间约束断层运动学和侧面动力学的价值。此外，这项工作为进一步研究k劳厄火山南翼的深层几何结构提供了新的基础。
{"title":"Volcano flank instability imaged by historical air photos correlation during the 1975 M.7.7 Kalapana earthquake (Kīlauea, Hawaii)","authors":"Stefano Mannini , James Hollingsworth , Nicolas Oestreicher , Joël Ruch","doi":"10.1016/j.jvolgeores.2025.108479","DOIUrl":"10.1016/j.jvolgeores.2025.108479","url":null,"abstract":"<div><div>The Kīlauea volcano is affected by flank instability related to recurrent volcano-tectonic events and large earthquakes. Yet, the connection between fracture zones and large recurrent earthquakes still remains poorly constrained, mainly because previous geodetic studies provided only sparse point measurements of coseismic deformation. Here we use optical image correlation of historical aerial photographs to analyze the ground displacement associated with the 1975 Kalapana earthquake (Mw 7.7). This approach allows us to reconstruct the spatially continuous distribution of coseismic deformation along the Hilina fault system, including areas that were poorly documented in earlier studies. Results show up to three meters of horizontal surface displacement along the 13 km long Hilina fault system. We observed that the entire main fault was reactivated during this event, with a westward increase of the displacement away from the earthquake epicenter. Our results indicate that the south flank of the volcano is strongly influenced by gravitational processes, with the Hilina fault likely serving as a boundary of a massive slump structure. Despite limitations due to the heterogeneity of the aerial photo acquisitions, this study provides the first detailed, continuous view of coseismic deformation along the Hilina faults during the Kalapana earthquake. Our results highlight the value of archival aerial imagery for constraining fault kinematics and flank dynamics during major historical earthquakes. Moreover, this work provides a new basis for future investigations of the deeper geometry of the Kīlauea volcano's south flank.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108479"},"PeriodicalIF":2.3,"publicationDate":"2025-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145363445","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 : 2025-10-22DOI: 10.1016/j.jvolgeores.2025.108475
Gaetano Ferrante , Helge Gonnermann , Céline Fliedner , Thomas Giachetti , Amy G. Ryan
{"title":"Corrigendum to “Viscosity of bubbly magmas from torsional experiments on pumice” [Journal of Volcanology and Geothermal Research 461 (2025) 108297]","authors":"Gaetano Ferrante , Helge Gonnermann , Céline Fliedner , Thomas Giachetti , Amy G. Ryan","doi":"10.1016/j.jvolgeores.2025.108475","DOIUrl":"10.1016/j.jvolgeores.2025.108475","url":null,"abstract":"","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108475"},"PeriodicalIF":2.3,"publicationDate":"2025-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145528405","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 : 2025-10-21DOI: 10.1016/j.jvolgeores.2025.108478
Prasanta K. Patro , S. Dhamodharan , Venkata Durga , K.K. Abdul Azeez , Narendra Babu , K. Chinna Reddy , Arvind K. Gupta , M. Shiva Krishna
The Panamik–Changlung hot springs, located along the Karakoram Fault (KF) in the Trans-Himalayan region of Ladakh in India, were investigated for the first time using the Magnetotelluric (MT) method to assess their geoelectrical properties. Situated in the Shyok–Nubra Valley between the Ladakh and Karakoram Batholiths, the region shows abundant geothermal manifestations. We acquired MT data along a 30 km profile parallel to the KF and performed 3D joint inversion of the impedance tensor and tipper data using the ModEM program. The resulting resistivity model reveals an upper crustal conductor (<10 Ω.m) at 4–10 km depth acting as geothermal reservoir with strong out-of-quadrant phases (>90° at periods >10 s) indicate a more complex system, potentially involving current channeling and electrical anisotropy. A shallower conductor (surface to ∼1.5 km) corresponds to sediments of Nubra Formation and fractured zones of the Karakoram Metamorphic Complex saturated with mixed thermal fluids and groundwater.
{"title":"Delineation of a geothermal source beneath the Panamik-Changlung Hot Springs along the Karakoram Fault, Ladakh, India, using magnetotelluric studies","authors":"Prasanta K. Patro , S. Dhamodharan , Venkata Durga , K.K. Abdul Azeez , Narendra Babu , K. Chinna Reddy , Arvind K. Gupta , M. Shiva Krishna","doi":"10.1016/j.jvolgeores.2025.108478","DOIUrl":"10.1016/j.jvolgeores.2025.108478","url":null,"abstract":"<div><div>The Panamik–Changlung hot springs, located along the Karakoram Fault (KF) in the Trans-Himalayan region of Ladakh in India, were investigated for the first time using the Magnetotelluric (MT) method to assess their geoelectrical properties. Situated in the Shyok–Nubra Valley between the Ladakh and Karakoram Batholiths, the region shows abundant geothermal manifestations. We acquired MT data along a 30 km profile parallel to the KF and performed 3D joint inversion of the impedance tensor and tipper data using the ModEM program. The resulting resistivity model reveals an upper crustal conductor (<10 Ω.m) at 4–10 km depth acting as geothermal reservoir with strong out-of-quadrant phases (>90° at periods >10 s) indicate a more complex system, potentially involving current channeling and electrical anisotropy. A shallower conductor (surface to ∼1.5 km) corresponds to sediments of Nubra Formation and fractured zones of the Karakoram Metamorphic Complex saturated with mixed thermal fluids and groundwater.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108478"},"PeriodicalIF":2.3,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145424715","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 : 2025-10-19DOI: 10.1016/j.jvolgeores.2025.108471
Carlos A. Angeles-De La Torre , Axel K. Schmitt , Axel Gerdes , Andreas Hertwig , Michael McCurry , Oscar M. Lovera
The bimodal Blackfoot Volcanic Field (BVF) in eastern Idaho hosts Middle–Late Pleistocene rhyolite domes that are among the youngest topaz rhyolites worldwide. Despite young volcanism in the BVF, its geothermal potential has remained elusive. To evaluate the magmatic and thermal evolution of the field, we investigated zircon crystals from seven domes by U-Pb and U-Th geochronology as well as correlative trace element and isotopic (δ18O, εHf) analysis. For the three northern domes and the central Sheep Island dome, zircon crystallization occurred between 1006 and 785 ka, indicating younger eruption ages than previously reported. Zircon populations from the three southern domes are on average distinctly younger (mostly 63.4–55.2 ka) and overlap literature 40Ar/39Ar ages. Zircon δ18O averages are overall similar (+4.54, +3.86, and + 4.45 for northern domes, Sheep Island dome, and southern domes, respectively), whereas εHf averages are more variable and strongly negative averaging −13.4, −15.3, and − 10.1 for the corresponding domes. These values indicate higher contributions of Archean crust to the BVF parental magmas and correspondingly lesser degrees of assimilation of low-δ18O rocks compared to coeval rhyolites from the axis of the Eastern Snake River Plain. Cooling and fractionation of a 120 km3 magma reservoir emplaced at 95 ka and 6 km depth successfully reproduces zircon ages, magma temperatures, and combined volumes for the southern domes and a geophysically inferred silicic intrusion. This indicates that temperatures at ∼4 km depth could still exceed 300 °C today, although the absence of geothermal surface manifestations and low temperatures encountered in a nearby exploration well suggests that thermal waters are diluted and diverted in a structurally controlled hydrological system.
{"title":"Provenance and thermal evolution of rhyolite magma in the Blackfoot volcanic field","authors":"Carlos A. Angeles-De La Torre , Axel K. Schmitt , Axel Gerdes , Andreas Hertwig , Michael McCurry , Oscar M. Lovera","doi":"10.1016/j.jvolgeores.2025.108471","DOIUrl":"10.1016/j.jvolgeores.2025.108471","url":null,"abstract":"<div><div>The bimodal Blackfoot Volcanic Field (BVF) in eastern Idaho hosts Middle–Late Pleistocene rhyolite domes that are among the youngest topaz rhyolites worldwide. Despite young volcanism in the BVF, its geothermal potential has remained elusive. To evaluate the magmatic and thermal evolution of the field, we investigated zircon crystals from seven domes by U-Pb and U-Th geochronology as well as correlative trace element and isotopic (δ<sup>18</sup>O, εHf) analysis. For the three northern domes and the central Sheep Island dome, zircon crystallization occurred between 1006 and 785 ka, indicating younger eruption ages than previously reported. Zircon populations from the three southern domes are on average distinctly younger (mostly 63.4–55.2 ka) and overlap literature <sup>40</sup>Ar/<sup>39</sup>Ar ages. Zircon δ<sup>18</sup>O averages are overall similar (+4.54, +3.86, and + 4.45 for northern domes, Sheep Island dome, and southern domes, respectively), whereas εHf averages are more variable and strongly negative averaging −13.4, −15.3, and − 10.1 for the corresponding domes. These values indicate higher contributions of Archean crust to the BVF parental magmas and correspondingly lesser degrees of assimilation of low-δ<sup>18</sup>O rocks compared to coeval rhyolites from the axis of the Eastern Snake River Plain. Cooling and fractionation of a 120 km<sup>3</sup> magma reservoir emplaced at 95 ka and 6 km depth successfully reproduces zircon ages, magma temperatures, and combined volumes for the southern domes and a geophysically inferred silicic intrusion. This indicates that temperatures at ∼4 km depth could still exceed 300 °C today, although the absence of geothermal surface manifestations and low temperatures encountered in a nearby exploration well suggests that thermal waters are diluted and diverted in a structurally controlled hydrological system.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108471"},"PeriodicalIF":2.3,"publicationDate":"2025-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145363446","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 : 2025-10-17DOI: 10.1016/j.jvolgeores.2025.108476
Haiyang Kuang , Jilong Yang , Jiangang Liang , Hu Ding , Jinfeng Yang
<div><div>Located in Haixing County, Hebei Province, along the western margin of Bohai Bay, Xiaoshan Volcano is one of two rare Quaternary volcanic outcrops on the North China Plain. Despite its significance as a critical marker for regional Quaternary stratigraphy and active tectonics in Bohai Bay, Xiaoshan Volcano has unresolved issues, including ambiguous subsurface architecture, debated eruption chronology, and inconsistent stratigraphic correlations; these issues collectively hinder the progress in deciphering the Cenozoic tectonic history and ongoing crustal deformation in western Bohai Bay. In this study, advanced geophysical prospecting techniques, such as magnetic, gravity, and two-dimensional seismic surveys, were carried out around Xiaoshan Volcano. Through a detailed analysis of various geophysical field characteristics and in combination with the results of drilling verification, the burial characteristics of the Quaternary volcano and the volcanic activity periods in the Xiaoshan area were investigated. The results show that the central part of the study area has high gravity and magnetic anomalies (with a residual gravity anomaly value of 0.3 mGal and a reduced-to-pole magnetic anomaly value of 305 nT), whereas the surrounding area has circular high magnetic anomalies and low residual gravity anomalies (with a residual gravity anomaly value of −0.25 mGal and a reduced-to-pole magnetic anomaly value of 56.45 nT). These anomalies correspond to the location of the volcanic eruption centre and the range of the volcanic cone. Gravity measurements also revealed two elliptical high-value anomalies of residual gravity in the study area. The high-value anomaly in the hinterland of Xiaoshan Volcano corresponds to the Xiaoshan crater, which is 1.5 km west of Xiaoshan Township and has a radius of approximately 200 m. Seismic exploration revealed that the magma conduit under the crater penetrated the Earth's surface. Another significant geophysical anomaly of residual gravity is located 1.5 km southwest of the crater, with a scale similar to that of the Xiaoshan crater. The 3D gravity inversion results suggest that the two are connected at depth and trend in a NE direction, which is consistent with the regional tectonic direction. It is inferred that there is a hidden crater beneath the surface in southwestern Xiaoshan.</div><div>Drilling investigations revealed three layers of volcanic rock strata within a depth range of 100 m, specifically at 61–80 m, 40–54 m, and 6–24 m. These strata correspond to the formation period of the Pleistocene Maar Lake, the formation period of the volcanic landform of the Pleistocene Xiaoshan volcanic cone, and the period of weak Holocene volcanic activity, respectively. On the basis of the electron spin resonance (ESR) dating results of the clay layer rich in volcanic ash in the first-layer accumulation of the X4 borehole in the Holocene deposits, which is 9807 ± 118 a BP, it is inferred that the last volcanic er
{"title":"Multisource geophysical data constraints on the deep structure and magmatic processes of Xiaoshan Volcano in Bohai Bay, China","authors":"Haiyang Kuang , Jilong Yang , Jiangang Liang , Hu Ding , Jinfeng Yang","doi":"10.1016/j.jvolgeores.2025.108476","DOIUrl":"10.1016/j.jvolgeores.2025.108476","url":null,"abstract":"<div><div>Located in Haixing County, Hebei Province, along the western margin of Bohai Bay, Xiaoshan Volcano is one of two rare Quaternary volcanic outcrops on the North China Plain. Despite its significance as a critical marker for regional Quaternary stratigraphy and active tectonics in Bohai Bay, Xiaoshan Volcano has unresolved issues, including ambiguous subsurface architecture, debated eruption chronology, and inconsistent stratigraphic correlations; these issues collectively hinder the progress in deciphering the Cenozoic tectonic history and ongoing crustal deformation in western Bohai Bay. In this study, advanced geophysical prospecting techniques, such as magnetic, gravity, and two-dimensional seismic surveys, were carried out around Xiaoshan Volcano. Through a detailed analysis of various geophysical field characteristics and in combination with the results of drilling verification, the burial characteristics of the Quaternary volcano and the volcanic activity periods in the Xiaoshan area were investigated. The results show that the central part of the study area has high gravity and magnetic anomalies (with a residual gravity anomaly value of 0.3 mGal and a reduced-to-pole magnetic anomaly value of 305 nT), whereas the surrounding area has circular high magnetic anomalies and low residual gravity anomalies (with a residual gravity anomaly value of −0.25 mGal and a reduced-to-pole magnetic anomaly value of 56.45 nT). These anomalies correspond to the location of the volcanic eruption centre and the range of the volcanic cone. Gravity measurements also revealed two elliptical high-value anomalies of residual gravity in the study area. The high-value anomaly in the hinterland of Xiaoshan Volcano corresponds to the Xiaoshan crater, which is 1.5 km west of Xiaoshan Township and has a radius of approximately 200 m. Seismic exploration revealed that the magma conduit under the crater penetrated the Earth's surface. Another significant geophysical anomaly of residual gravity is located 1.5 km southwest of the crater, with a scale similar to that of the Xiaoshan crater. The 3D gravity inversion results suggest that the two are connected at depth and trend in a NE direction, which is consistent with the regional tectonic direction. It is inferred that there is a hidden crater beneath the surface in southwestern Xiaoshan.</div><div>Drilling investigations revealed three layers of volcanic rock strata within a depth range of 100 m, specifically at 61–80 m, 40–54 m, and 6–24 m. These strata correspond to the formation period of the Pleistocene Maar Lake, the formation period of the volcanic landform of the Pleistocene Xiaoshan volcanic cone, and the period of weak Holocene volcanic activity, respectively. On the basis of the electron spin resonance (ESR) dating results of the clay layer rich in volcanic ash in the first-layer accumulation of the X4 borehole in the Holocene deposits, which is 9807 ± 118 a BP, it is inferred that the last volcanic er","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"468 ","pages":"Article 108476"},"PeriodicalIF":2.3,"publicationDate":"2025-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145363371","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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