Journal of Volcanology and Geothermal Research最新文献

{"title":"Changes in seismicity in a volcanically active region of the Izu Peninsula, Japan","authors":"K.Z. Nanjo ,&nbsp;Y. Yukutake ,&nbsp;T. Kumazawa","doi":"10.1016/j.jvolgeores.2025.108355","DOIUrl":"10.1016/j.jvolgeores.2025.108355","url":null,"abstract":"<div><div>The eastern Izu Peninsula in Japan is volcanically and seismically active. Ordinary earthquakes frequently occurred at shallow depths in 2006 and 2009, when they clustered as swarms. Beneath ordinary earthquakes, low-frequency earthquakes (LFEs) were infrequently observed. To better understand the characteristics of those LFEs, we produced a LFE catalog for 2005–2020, using the matched-filter method. Timeseries analyses based on the Epidemic-Type Aftershock Sequence model showed quiescence, i.e., a change in occurrence rate, which became quiet. For comparison, the same analysis was conducted using the Japan Meteorological Agency catalog of ordinary earthquakes, and similar results were shown. The change points for both types of earthquakes fell during and after each of the swarms, revealing an earlier start of quiescence for shallow ordinary earthquakes than for deep LFEs. Surface displacement data obtained from the Geospatial Information Authority of Japan showed that the uplift was in abatement or unobservable during the study period. Our seismicity and geodetic results are interpretatively hypothesized as being associated with magmatic activity, as follows. When the absence of a supply of magma from a depth toward the crustal magma reservoir caused no significant uplift, magma intruded from this reservoir into the shallow crust, resulting in the 2006 and 2009 swarms. Due to this intrusion, stresses decreased in and around shallow parts of the reservoir and then quiescence for ordinary earthquakes began during or after each swarm. Due to this decrease, stresses in and around deep parts of it late decreased, delaying the start of quiescence of deep LFEs.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"465 ","pages":"Article 108355"},"PeriodicalIF":2.4,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143947368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical experiments of geyser eruption caused by ascent-driven decompression boiling, using the wellbore-reservoir simulator T2Well/ECO2N","authors":"Ayuta Tsuge ,&nbsp;Hiroshi Aoyama","doi":"10.1016/j.jvolgeores.2025.108366","DOIUrl":"10.1016/j.jvolgeores.2025.108366","url":null,"abstract":"<div><div>The eruption processes of geysers, particularly those involving a two-phase flow of water and vapor, remain insufficiently understood due to the inherent difficulties in conducting direct observations within the conduit. To address this, we conducted numerical experiments focusing on geysers caused by ascent-driven decompression boiling, using the T2Well/ECO2N wellbore-reservoir coupled two-phase flow simulator. Our simulations successfully reproduced the periodic eruption driven by the decompression boiling of water and CO₂ under specific conditions. The typical characteristics of the simulated eruption cycles were consistent with those commonly observed in natural geysers situated in and around volcanic fields. The CO₂ dissolved in water initiated boiling at deeper depths due to its partial pressure, though it had a limited impact on the explosivity of the eruptions. Sensitivity tests, conducted by varying conditions within the aquifer, reservoir, and atmosphere indicated that permeability and hydraulic head control the average flow rate to the wellbore. In contrast, factors such as the CO₂ mass fraction in the liquid phase, temperature, and barometric pressure significantly influence the boiling process during eruptions. Furthermore, we described a physical mechanism underlying the eruption process based on the spatiotemporal variation in physical parameters within the conduit. Specifically, the initiation and termination of eruptions may be governed by a self-enhancing process occurring at shallow depths with large temperature gradients and a self-limiting process at greater depths with small temperature gradients. Although we assumed simplified geometry and used limited thermodynamic conditions, our results may provide valuable insights into the dynamics of geyser eruptions.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"465 ","pages":"Article 108366"},"PeriodicalIF":2.4,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143936732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Slab morphology and associated seismic and volcanic activities beneath Sulawesi Island, Indonesia","authors":"Bagus Adi Wibowo ,&nbsp;Ling Bai ,&nbsp;Supriyanto Rohadi ,&nbsp;David Prambudi Sahara ,&nbsp;Zhiwen Chen ,&nbsp;Karyono Karyono ,&nbsp;Yosi Setiawan ,&nbsp;Putu Hendra Widyadharma ,&nbsp;Abraham Arimuko ,&nbsp;Anisa Nurbaeti Rahayu ,&nbsp;Suko Prayitno Adi ,&nbsp;Dwikorita Karnawati","doi":"10.1016/j.jvolgeores.2025.108352","DOIUrl":"10.1016/j.jvolgeores.2025.108352","url":null,"abstract":"<div><div>The Sulawesi Island, Indonesia, represents a complex deformation with multiple subducting slabs and produces frequent earthquake, volcano, and tsunami hazards. Here, we investigate lithospheric velocity structures beneath Sulawesi Island to study the subducting slabs and their associated seismicity and volcanism. P- and S-wave arrival time data are acquired from the dense seismic network of the Indonesia Tsunami Early Warning System. We collected 192,301 P-wave and 40,345 S-wave phases arrival time data from 10,421 earthquakes with 2.5 ≤ Mw ≤ 7.5 that occurred between 2017 and 2022. Earthquake data are recorded by 137 InaTEWS seismic stations which provide sufficient ray path density for the entire Sulawesi Island. There are high velocity anomalies for subducting slabs and low velocity anomalies beneath active volcanoes. These observations revealed southward subduction of the Celebes slab, northward subduction of the Banggai-Sula slab, southwest subduction of the Sangihe slab, and double subduction of the Sangihe and Halmahera arcs northeast of the Sulawesi Island. The 2018 Mw7.5 Palu earthquake occurred on the left-lateral strike-slip Palu-Koro fault, which was formed by the northward subduction of the Banggai-Sula slab with respect to the Makassar Strait. The 2018 Mw7.5 Palu earthquake sequence and the 2018 Mamasa earthquake swarm are located with low Vp and Vs anomalies, probably due to the combination of active fault activity and fluid migration.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"465 ","pages":"Article 108352"},"PeriodicalIF":2.4,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143947369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seismic activity that accompanied the lava dome eruptions at andesitic Volcán de Colima (2016–2017) and dacitic Mount St. Helens (2004–2008)","authors":"Vyacheslav M. Zobin","doi":"10.1016/j.jvolgeores.2025.108353","DOIUrl":"10.1016/j.jvolgeores.2025.108353","url":null,"abstract":"<div><div>Lava domes are formed when the erupted lava is too viscous to flow freely away from the vent. All processes of lava domes growth and destruction are accompanied with seismic activity. This article presents the comparative analysis of the seismic signals, recorded during the episodes of lava dome eruptions at andesitic Volcán de Colima and dacitic Mount St Helens. The seismic signals, associated with two end-member styles of lava dome growth: endogenous at Volcán de Colima, in which new lava is added to the interior of an inflating dome, and exogenous at Mount St Helens, in which new lava accumulates as the lava spines on the dome surface, are discussed. The difference in the characteristic features of the endogenous and exogenous styles of the lava dome building and destruction, reflected in the seismic signals, is demonstrated. The most reason for the noted difference of the seismic development of these two eruptions is proposed to be in the difference in the gas-filling properties of magma, gas-rich at Volcán de Colima and gas-poor at Mount St Helens.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"465 ","pages":"Article 108353"},"PeriodicalIF":2.4,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144083953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seismic source mechanism of the tsunami near the Sofu Seamount on October 8, 2023","authors":"M. Yamada ,&nbsp;M. Nakano","doi":"10.1016/j.jvolgeores.2025.108354","DOIUrl":"10.1016/j.jvolgeores.2025.108354","url":null,"abstract":"<div><div>On October 8, 2023, between 18:50 and 22:00, a cluster of earthquakes occurred near Sofu Seamount, and a tsunami advisory was issued for the surrounding areas. Previous studies showed that the main source of this tsunami was an uplift near the Sofu Seamount and the tsunami could be simulated by the summation of the multiple sources over time. To clarify the seismic mechanism of this volcanic activity, we performed the seismic waveform inversion and cross-correlation analysis. We obtained the source-time function of the 13 repeated earthquakes and found that the source mechanism of the tsunamigenic event was a force symmetric about the vertical axis, such as single-force, isotropic, or vertical compensated-linear-vector-dipole (CLVD) mechanisms. We also found that there were low-frequency harmonic signals between earthquakes, which do not come with clear body waves. We interpreted these signals as a caldera collapse and resonance of the magma reservoir. The repeated earthquakes can be interpreted as the vertical movement of the rock column, supplying magma to the magma chamber and causing the uplift of the caldera floor that excited tsunamis. The harmonic signals between earthquakes may be the resonance at the magma reservoir associated with the magma migration. We assumed that the edifice subsided slowly between earthquakes and repeated this inflation-deflation cycle along with the earthquakes.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"464 ","pages":"Article 108354"},"PeriodicalIF":2.4,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143932243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of lateral dyke propagation and pre-existing fractures on shallow deformation: Data from the Etna 1947 eruption and analogue models","authors":"A. Tibaldi ,&nbsp;A. Luppino ,&nbsp;E. De Beni ,&nbsp;N. Corti ,&nbsp;M. Cantarero ,&nbsp;F. Pasquarè Mariotto ,&nbsp;F.L. Bonali","doi":"10.1016/j.jvolgeores.2025.108349","DOIUrl":"10.1016/j.jvolgeores.2025.108349","url":null,"abstract":"<div><div>Mount Etna, one of Europe's most active volcanoes, has experienced a variety of eruption settings throughout its history, including summit, lateral, and eccentric eruptions. In this study, we provide a detailed analysis of the structures formed during the 1947 lateral eruption, along the NE Rift, using historical aerial photos and accounts, archival images, and contemporary field and drone data. Photogrammetric processing of 1932 and 1954 aerial photos enabled us to map the structures formed before and during the eruption, in order to examine the effects of pre-existing fractures on the 1947 deformation pattern. With the aid of field surveys, we studied 90 normal faults, 194 dry fractures and 17 eruptive fissures, collecting data on the structures' length, azimuth, vertical offset, vectors and amount of opening. The reconstruction of a detailed chronology of the eruption's day-by-day development, allowed us to characterize the event as a NE-directed, lateral propagation of magma along a N-S to NE-SW-striking dyke, which followed the path of a previous similar event. Based on the reconstruction of the fault-slip profiles at both sides of various 1947 grabens, we were able to show that fault scarps taper towards NE. Analogue models were also used to simulate the lateral intrusions of dykes and the consequent formation of shallow structures. All the data suggest that the formation of the various structures, with different geometry and deformation, depends upon a combination of magma overpressure, local topography, external stresses, pre-existing structures, and direction of magma propagation.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"464 ","pages":"Article 108349"},"PeriodicalIF":2.4,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143927840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrogeochemical characterization of mineral waters from Fogo Volcano (São Miguel, Azores)","authors":"L. Ferreira ,&nbsp;J. Virgílio Cruz ,&nbsp;F. Viveiros ,&nbsp;N. Durães ,&nbsp;C. Andrade ,&nbsp;N. Cabral ,&nbsp;J.F. Santos","doi":"10.1016/j.jvolgeores.2025.108348","DOIUrl":"10.1016/j.jvolgeores.2025.108348","url":null,"abstract":"<div><div>Mineral waters discharges of Fogo volcano (São Miguel Island, Azores) present a wide range of physico–chemical characteristics. These discharges may be divided into thermal waters, with temperatures as high as 58.4 °C and some with acidic pH (2.4–3.3), and cold waters, some of them with high dissolved CO₂ concentrations (maximum value = 1028 mg.L⁻¹). There is a negative correlation between pH and temperature, ascribed to volcanic input, and a positive correlation between electrical conductivity and the concentration in HCO₃, usually associated with rock weathering. These waters do not exhibit a significant seasonal variation of the major components and physico–chemical parameters. Nevertheless, rare earth elements and ⁸⁷Sr/⁸⁶Sr ratios point to an incongruent dissolution of the rock, with some samples depicting a seasonal influence, which is related to different proportions of rock weathering. Based on the analyzed samples and the subsurface geology, it was possible to distinguish different perched–aquifers systems in Fogo, associated to lava flows sequences. Caldeiras da Ribeira Grande is characterized by thermal and acid–sulfate waters, and Lombadas presents a shallower aquifer system, with high CO₂ influx and higher concentrations of rock–forming elements.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"464 ","pages":"Article 108348"},"PeriodicalIF":2.4,"publicationDate":"2025-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143890860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Constraining the timing and climate forcing of the Long Island (Papua New Guinea) and Tarumae (Japan) eruptions and other 17th century volcanic eruptions","authors":"Imogen Gabriel ,&nbsp;Helen M. Innes ,&nbsp;Peter M. Abbott ,&nbsp;Jörg Franke ,&nbsp;Melanie Behrens ,&nbsp;Nathan J. Chellman ,&nbsp;Maria Hörhold ,&nbsp;William Hutchison ,&nbsp;Joseph R. McConnell ,&nbsp;Birthe Twarloh ,&nbsp;Michael Sigl","doi":"10.1016/j.jvolgeores.2025.108346","DOIUrl":"10.1016/j.jvolgeores.2025.108346","url":null,"abstract":"<div><div>The 17^th century was a period when several major (VEI &gt; 5) tropical and extratropical volcanic eruptions occurred. Amongst these is the VEI 6 eruption of Long Island (Papua New Guinea), which is suggested to have occurred between 1665 and 1668 CE based on historical accounts, radiocarbon dating constraints, and an ice-core record from South Pole. Accepting such an attribution on the basis of this ice-core chronology would imply a hitherto undiagnosed dating error of up to 6 years during the 17^th century within all ice-core records from Antarctica. Here we constrain the timing of the Long Island eruption through tephrochronology and high-resolution glaciochemical measurements from an array of records from Antarctica and Greenland. We identify cryptotephra glass shards in association with the Greenland 1667 CE sulfate peak and geochemically attribute them to the historic Japanese Tarumae (Shikotsu) eruption. This attribution shows that the ice-core records are not misaligned during this period and refines the timing of the Long Island eruption to two candidate dates: 1654 ±1 CE and 1662 ±1 CE. Both candidate dates are within previous best age estimates based on radiocarbon dating (1651 and 1671 CE, 95.4 % probability). However, here we tentatively use 1662 ±1 CE as the timing of the Long Island eruption, as previous radiocarbon constraints suggest a 68.2 % probability of occurrence between 1655 and 1665 CE. With a higher confidence in the dating, we revised volcanic stratospheric sulfur injection (VSSI) estimates across the 17^th century. Using these alongside paleo-proxy records, we explored the Northern Hemisphere climate response to the Long Island and Tarumae eruptions and found them to be more limited compared to other major (VEI &gt;5) eruptions during this century. Ultimately, this study has highlighted the accuracy of ice core chronologies, having wider implications for volcanic forcing reconstructions and detection and attribution studies of natural climate variability.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"464 ","pages":"Article 108346"},"PeriodicalIF":2.4,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143890864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reconstructing the volcanic history of the Ulukışla Caldera: A collapse structure within the Hasandağ Volcanic Complex, Central Anatolia (Turkey)","authors":"Rengin Özsoy ,&nbsp;Ivan Sunyé-Puchol ,&nbsp;Xavier Bolós ,&nbsp;Efe Akkaş ,&nbsp;Antonio Costa ,&nbsp;Lorenzo Tavazzani ,&nbsp;Daniel P. Miggins ,&nbsp;Manuela Nazzari ,&nbsp;Olivier Bachmann ,&nbsp;Piergiorgio Scarlato ,&nbsp;Silvio Mollo","doi":"10.1016/j.jvolgeores.2025.108345","DOIUrl":"10.1016/j.jvolgeores.2025.108345","url":null,"abstract":"<div><div>The Ulukışla Caldera is a collapse structure within the active Hasandağ Volcanic Complex (Central Anatolia), situated along the southern branch of the Tuz Gölü Fault Zone (TGFZ). This study aims to reconstruct the volcanic history of the Ulukışla Caldera by characterising its associated pyroclastic deposits using tephrostratigraphy, glass chemistry (major and trace elements), and geochronological data (⁴⁰Ar/³⁹Ar and U-(Th)-Pb). Our findings reveal that the Ulukışla Caldera has undergone at least three major explosive rhyolitic eruptions, which formed the pyroclastic deposits of the Yenipınar Eruption (∼442 ka), the Belbaşhanı Eruption (∼400 ka), and the Ulukışla Eruption (∼326 ka). The Yenipınar unit was produced by an unsteady eruption column originating from paleo-Ulukışla volcanic structure, that deposited pumice fallout layers and interbedded pyroclastic density current (PDC) deposits. The Belbaşhanı Eruption began with a Plinian column that deposited the Belbaşhanı Pumice fallout. This phase was followed by the emplacement of thick PDC deposits and co-ignimbrite lithic lag breccias during the collapse, which ultimately led to the formation of the Ulukışla Caldera. The volume of the Belbaşhanı deposits, including the pumice fallout and the caldera-forming ignimbrite, could reach up to 10 km³ DRE (Dense Rock Equivalent), corresponding to an eruption of magnitude ∼6. The Ulukışla Pumice resulted from a post-caldera eruption, which did not generate PDCs. The Ulukışla Caldera exhibits an elongated morphology, which is strongly influenced by the NW-SE alignment of the TGFZ. Based on this morphology and the regional tectonic setting, we conclude that the Ulukışla Caldera is a strike-slip/graben caldera. Reconstructing the volcanic history of this newly identified caldera is essential for enhancing our understanding of the Hasandağ Volcanic Complex. Our findings offer valuable context for future eruptive behaviour, improving the hazards assessment for potential caldera collapses, and contribute to mitigating associated risks.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"463 ","pages":"Article 108345"},"PeriodicalIF":2.4,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143855568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Does the Lost Jim lava flow (Alaska) really preserve evidence of interaction with permafrost?","authors":"Tim R. Orr ,&nbsp;William M. Coombs ,&nbsp;Erika Rader ,&nbsp;Jessica Larsen","doi":"10.1016/j.jvolgeores.2025.108347","DOIUrl":"10.1016/j.jvolgeores.2025.108347","url":null,"abstract":"<div><div>The basaltic Lost Jim lava flow, the youngest member of the Imuruk Lake volcanic field, Alaska, is reported to have interacted with underlying permafrost by thawing it and forming cavities into which the lava flow collapsed, forming pits and other depressions on the lava flow's surface. Our field observations contradict this hypothesis. The Lost Jim lava flow exhibits surface features typical of an inflated pāhoehoe flow, and we propose instead that most of the pits are unambiguously the result of flow inflation (i.e., lava-rise pits). These pits are found on elevated, relatively level surfaces, and their inner walls preserve features like rotated surface slabs and fine-scale flow banding on exposed crack surfaces, both of which are hallmarks of lava flow inflation. While collapse pits do exist on the Lost Jim lava flow, they are morphologically distinct and formed by crustal failure into drained lava tubes.</div><div>Satellite images of the Lost Jim lava flow show similarities in the size and distribution of pits within other young pāhoehoe lava flows scattered across the globe. The small diameter of many of the pits (&lt;10 m), compared to flow thickness (≥10 m), also argues against collapse—numerical modeling shows that the relatively high tensile strength of a coherent lava flow would have prevented its collapse into cavities similar in diameter to the lava flow's thickness. Finally, the pits are found scattered across the Lost Jim lava flow, including in locations where the lava flow rests directly on bedrock, which consists of older lava flows. Segregated ice lenses and soil expansion—necessary components for thermokarst formation when thawed—do not exist in such locations. Altogether, these factors show that the Lost Jim lava flow is an inflated lava flow, and permafrost played no significant role during or after its emplacement.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"464 ","pages":"Article 108347"},"PeriodicalIF":2.4,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143932205","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}