Journal of Geophysical Research: Solid Earth最新文献

{"title":"Porous and Permeable Crystalline Basement: Evidence for Large-Scale Hydraulic Connectivity at Kivetty, Finland","authors":"Daniel Carbajal-Martínez,&nbsp;Michael J. Heap,&nbsp;Ester M. Jolis,&nbsp;Toni Luoto,&nbsp;Thierry Reuschlé,&nbsp;Satu Vuoriainen,&nbsp;Jukka Kuva,&nbsp;Evgenii Kortunov,&nbsp;Alan Bischoff","doi":"10.1029/2026JB034512","DOIUrl":"https://doi.org/10.1029/2026JB034512","url":null,"abstract":"<p>Porosity and permeability in crystalline shield basement are commonly assumed to be low, yet some fault zones sustain fluid circulation over kilometer scales. Here we quantify multiscale fault-zone connectivity at Kivetty, central Finland, by integrating legacy deep-borehole data, including packer tests, downhole logs, and a long-term multi-borehole pumping test, with new core logging, laboratory petrophysics, mineral mapping, and X-ray computed tomography (XCT). We show that the most transmissive intervals occur within the fault core and are dominated by breccia–open and altered–leached granitic rocks with high porosity and permeability. These rocks are characterized by quartz depletion, biotite dissolution and alteration, including replacement by chlorite and epidote, and abundant matrix porosity expressed as microporosity, intercrystalline and intracrystalline pores, and vugular cavities. Core-plug porosity reaches 30%, XCT shows that up to 94% of the pore space is connected, and the most permeable plugs remain in the ∼10⁻¹³ m² range at 50 MPa, corresponding to a confining pressure at ∼2 km depth. At borehole scale, permeability is concentrated in discrete sub-intervals (10⁻¹⁴–10⁻¹² m²), and hydraulic responses up to ∼1 km from the pumping interval indicate kilometer-scale connectivity in the fault system. These results show that coupled brittle deformation and hydrothermal alteration can generate connected pore networks through brecciation and leaching, allowing crystalline fault cores to sustain high permeability and large-scale fluid flow rather than act as seals where reaction-enhanced porosity is preserved. Our findings provide a basis for assessing analogous fault-controlled reservoirs in crystalline basement.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JB034512","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148849254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Continuous Release of Saline Fluids From a Permeable Subducting Slab","authors":"Yongsheng Huang,&nbsp;Yinwei Li,&nbsp;Kaiwei Tao,&nbsp;Guoji Wu,&nbsp;Masanari Arao,&nbsp;Michihiko Nakamura,&nbsp;Duojun Wang,&nbsp;Yuan Li","doi":"10.1029/2026JB034130","DOIUrl":"https://doi.org/10.1029/2026JB034130","url":null,"abstract":"<p>The mobility of aqueous fluids in subducting slabs fundamentally controls volatile and element cycling, yet the efficiency of fluid extraction from eclogitized oceanic crust remains poorly constrained. While NaCl is a key solute in subduction zone fluids, its specific role in controlling fluid connectivity in slab eclogite has not been quantified. Here, we present systematic measurements of dihedral angles (<i>θ</i>) in the eclogite–NaCl–H₂O system at 2–15 GPa and 800–1200°C. The addition of NaCl reduces garnet–fluid–garnet, garnet–fluid–clinopyroxene, and clinopyroxene–fluid–clinopyroxene <i>θ</i> below the 60° interconnectivity threshold under all investigated conditions. Notably, fluid connectivity (<i>θ</i> &lt; 60°) is established with only 1 wt.% NaCl at 2 GPa and 800°C, whereas complete wetting (<i>θ</i> ≈ 0°) occurs at pressures ≥9 GPa and 1200°C. These results demonstrate that saline fluids form interconnected networks within eclogitized slabs, enabling efficient and pervasive fluid release in global subduction zones. This mechanism provides a direct mechanism for continuous element fluxing, metasomatism, and flux melting in the mantle wedge. Consequently, our findings imply that subducting oceanic crust is unlikely to transport significant free water to the deep mantle; instead, the deep mantle water inventory may be governed by water stored in hydrous and/or nominally anhydrous minerals.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148849190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"GIA-Induced Mantle Circulation and Surface Horizontal Motions in North America: Effects of 3D Laterally Varying Elastic Thickness and Viscosity","authors":"Kaixuan Kang,&nbsp;Thorsten W. Becker","doi":"10.1029/2025JB033462","DOIUrl":"https://doi.org/10.1029/2025JB033462","url":null,"abstract":"<p>The horizontal surface motions of the Earth's crust induced by glacial isostatic adjustment (GIA) are highly sensitive to lateral variations in Earth properties. We construct 3D GIA models by incorporating both varying elastic lithospheric thickness and lateral viscosity variations in the asthenosphere in a global, compressible, self-gravitating, viscoelastic Earth model. This allows us to investigate how geological structures such as the North American continental craton with thick lithosphere and stiff upper mantle and oceanic plate regions with thinner lithosphere and weak asthenosphere influence mantle flow during and after the last deglaciation and how this relaxation is expressed in surface motions. While vertical crustal motions are always in phase with the ice loading change, horizontal motions can be out of phase with the glaciation history and vertical motions. The delay in response to deglaciation and the timing of the direction reversal after deglaciation is complete are controlled by the interplay between elastic lithospheric flexure and the mantle viscous drag on the base of the lithosphere. The weak asthenosphere channels the mantle return flow more horizontally and the stiff cratonic root directs the flow more vertically, forming a “box-like” circulation beneath the former ice cover. Such complex interactions may be better constrained with joint geodetic and seismic anisotropy analysis and provide new perspectives for GIA-ice sheet interactions as well as the interpretation of GIA associated seismotectonics.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JB033462","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148848991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mapping the Crustal Thickness of the Andes Using pmP Phases Identified From Adaptive Teleseismic Array Data","authors":"Alice Blackwell,&nbsp;Timothy Craig,&nbsp;Sebastian Rost,&nbsp;Hanna-Riia Allas","doi":"10.1029/2025JB032429","DOIUrl":"https://doi.org/10.1029/2025JB032429","url":null,"abstract":"<p>Crustal thickness (or Moho depth) is a key parameter for many geological and geophysical models. Despite this we have a limited number of measurements, typically from seismic receiver functions, to constrain variations in crustal thickness. Here we present an automatic methodology where we leverage array processing techniques and the increasing density of teleseismic data, to identify near-source Moho reflector phases, specifically <i>pmP</i>, from intermediate-depth and deep focus earthquake recordings. Using the differential travel times between the depth phase <i>pP</i> and its Moho precursor <i>pmP</i> to determine Moho depths at the <i>pmP</i> bounce points, we construct a crustal thickness map for the South American Subduction Zone, based on 2,588 <i>pmP</i> detections. The approach compares favorably to previous receiver function studies in the region, and enables the generation of continental-scale high resolution Moho depth maps with a greater number of defining data points, automatically, for supra-subduction zone regions, without the need for local instrumentation. Furthermore, we spatially analyze the relative amplitudes between <i>pmP</i> and <i>pP</i>, and infer dry, high velocity, uncoupled mantle overlying the Peruvian flat slab, which viscously couples at the distal bend subducting into the mantle. Overall, we present a powerful approach to study local to continental-scale crustal structure and subduction dynamics in areas with limited seismic infrastructure.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JB032429","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148816677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stability of Water-Bearing Aluminous Silica Phases in Subducted Oceanic Crust: Implications for Water Transport to the Core-Mantle Boundary","authors":"Yao Yao,&nbsp;Lu Liu,&nbsp;Ziqiang Yang,&nbsp;Li Zhang,&nbsp;Xueyan Du,&nbsp;Yanping Yang,&nbsp;Philip Dalladay-Simpson,&nbsp;Federico A. Gorelli,&nbsp;Mohamed Mezouar,&nbsp;Lili Zhang,&nbsp;Shuai Yan,&nbsp;Yuzhu Wang,&nbsp;Xi Liu,&nbsp;Eiji Ohtani","doi":"10.1029/2026JB034479","DOIUrl":"https://doi.org/10.1029/2026JB034479","url":null,"abstract":"<p>Geochemical evidence indicates the presence of H₂O sources in the deep mantle that feed plume-related magmatism. Understanding water storage and phase changes in multicomponent systems relevant to subducted oceanic crust would provide important constraints on the deep-Earth water cycle. Here we conducted experiments in the MgO-Al₂O₃-Fe₂O₃-SiO₂-H₂O systems over pressure-temperature (<i>P</i>-<i>T</i>) range of 94–134 GPa and 2,100–2,500 K. In our experiments, we found that NiAs-type silica (Nt) phase is stable in H₂O-bearing basaltic composition along normal geotherm conditions of the deep lower mantle. We conducted additional experiments in an alumina-poor H₂O-bearing system and obtained CaCl₂-type silica (Ct) instead under <i>P-T</i> conditions of the Nt phase stability field, indicating a phase boundary between Nt and Ct. The high alumina content in basaltic composition coupled with H₂O is needed to stabilize the NiAs-type structure of silica. Coexistence of aluminous silica and pyrite-type FeOOH was observed under <i>P-T</i> conditions corresponding to &gt;2,300 km depth. Our results indicate that the water storage phases in the deep lower mantle are dependent on the bulk composition, H₂O concentration and <i>P-T</i> conditions. The presence of H₂O greatly alters the mineralogy in the deep lower mantle and might play an important role in mantle dynamics.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148816493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bayesian Inference of Complex Stress Evolution in Rate-and-State Governed Faults Constrained by Seismicity Rate Observations","authors":"Y. Jiang,&nbsp;D. T. Trugman,&nbsp;P. J. González","doi":"10.1029/2026JB033922","DOIUrl":"https://doi.org/10.1029/2026JB033922","url":null,"abstract":"<p>Temporal changes in seismicity rates can be conceptually understood as a response and consequence of stress changes. Dieterich (1994, https://doi.org/10.1029/93JB02581) formalized this relationship using empirically derived rate-and-state friction laws, and Heimisson and Segall (2018, https://doi.org/10.1029/2018JB015656) later generalized the model to allow variable stressing histories. Current practical applications rely on externally modeled stress inputs, simplified stress histories, or lack uncertainty quantification, limiting their ability to fully resolve time-dependent stress evolution from seismicity alone. Here, we propose a physics-informed Bayesian inversion framework that infers stress rate evolution using a flexible trapezoidal-shaped source function from seismicity rates. This framework enables reconstruction of temporal stress evolution and uncertainties using earthquake catalogs as the primary observational constraint. We validate the method through synthetic sensitivity tests. We apply it to the 2008 Reno-Mogul, Nevada, earthquake swarm and identify multiple stress-loading phases. The final loading phase, beginning 3 days before the M5.1 earthquake, reveals a transient stress increase consistent with aseismic fault slip and offers a plausible explanation for the rapid foreshock cluster preceding it. Sensitivity tests show that the timing of this late transient is relatively stable across the tested preprocessing choices, whereas its stress amplitude depends strongly on the assumed background seismicity rate <i>r</i>. This interpretation is supported by significant surface displacement signals in independent GPS time series during the final phase. Our model and accompanying tool (<i>T-rate</i>) provide a simple, physics-informed approach to explore stress evolution consistent with seismicity rate observations, enabling new insights into earthquake swarms, even in regions lacking dense geodetic coverage.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JB033922","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148848904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improving Earthquake Forecasting for Europe Using Elliptic ETAS Aftershock Distribution Kernels","authors":"M. Han,&nbsp;L. Mizrahi,&nbsp;S. Wiemer","doi":"10.1029/2026JB033834","DOIUrl":"https://doi.org/10.1029/2026JB033834","url":null,"abstract":"<p>In the standard Epidemic-Type Aftershock Sequence (ETAS) model, widely used for earthquake forecasting, aftershocks are distributed isotropically in space—in circular symmetry around the triggering event. This simplification neglects fault geometry and observed anisotropy in aftershock distributions. In this study, we introduce directional information into the ETAS model by replacing the circular kernel with an elliptic one during parameter inversion procedure based on Expectation–Maximization. Using real catalogs from the European region, we investigate the impact of this modification on forecasting capability in retrospective and pseudo-prospective evaluations. Our findings suggest that incorporating directional anisotropy by estimating ellipses using aftershock spatial distribution can significantly improve model performance, as well as reduce bias in the estimated ETAS parameters, specifically those controlling the productivity component. We also explore the limitations of estimating anisotropy in real time, proposing strategies to overcome the delay in obtaining reliable directional information.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JB033834","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148848932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cenozoic Post-Collisional Au-Rich Porphyry System Imaged by a High-Density Seismic Array and Magma Records in the SE Margin of the Tibetan Plateau","authors":"Jue Hou,&nbsp;Guiping Yu,&nbsp;Bo Xu,&nbsp;Yingjie Yang,&nbsp;Xiaobo Tian,&nbsp;Tianyang Gao,&nbsp;Maowen Yuan,&nbsp;Zhuang Miao,&nbsp;Lei Gao,&nbsp;Nian Yu","doi":"10.1029/2025JB033663","DOIUrl":"https://doi.org/10.1029/2025JB033663","url":null,"abstract":"<p>Post-collisional porphyry Cu-Au deposits are prime targets for modern exploration, yet the source and intra-crustal evolution of the associated magma remain poorly constrained. Here, we image the fine structure of the ∼45 km thick cratonic crust underlying the Beiya Au-Cu deposit, an Eocene post-collisional porphyry ore system, using a 268 km long dense short-period seismic array across the eastern Tibetan plateau. Our receiver function image reveals, for the first time, two groups of positive seismic features with high Vp/Vs ratios in the lower crust. Integrated with published joint Vs inversion image, lower crustal xenolith records, and Sr-Nd isotope simulation, our results indicate that the lower crust was locally modified by previous subduction and later melt to generate the Eocene fertile magma during collision. Ambient noise tomography further reveals three low-Vs bands, extending obliquely upward from 8 to 2 km depth, spatially coinciding with collision-inducted strike-slip faults. Vertical Vs gradients identify two distinct centers in each low-velocity band, located at ∼6 km and at &lt;2 km depth, respectively. These observations, together with P-T estimation of crystallized minerals from Eocene porphyries, indicate that the fertile magma evolved within a chamber at ∼6 km depth and then ascended upward along a strike-slip fault into the upper crust, where it accumulated in shallow cupolas at depths of 1–2 km and ultimately formed the Beiya deposit. We propose that a closed magma chamber with a volume &gt;100 km³ in the shallow crust is a key factor controlling the formation of such deposits. Our study provides a typical example for understanding the intra-crustal magma system associated with post-collisional porphyry deposits.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148848800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Emplacement Conditions and Alteration of Volcanic Deposits Inferred From Magnetic Properties of the ICDP Eger Drill Site S4 (Bažina Maar), Czechia","authors":"Johanna Berckhan,&nbsp;Agnes Kontny,&nbsp;Katarzyna Dudzisz,&nbsp;Jan Mrlina,&nbsp;Norbert Nowaczyk,&nbsp;Simo Spassov,&nbsp;Franziska D. H. Wilke","doi":"10.1029/2025JB033665","DOIUrl":"https://doi.org/10.1029/2025JB033665","url":null,"abstract":"<p>Titanomagnetite in alkaline maar deposits exhibits variable syn- and post-crystallization alteration linked to wet emplacement and groundwater fluctuations, which remain poorly documented. Magnetic and mineralogical analyses of lapilli, scoria, and basalt from ICDP Eger drill cores S4 and S4b (Bažina maar, western Eger Graben, Czechia) reveal systematic depth-dependent changes in magnetic properties, fabric, and mineralogy. Effusive basaltic units host Ti-rich titanomagnetite with Curie temperatures of 170°–240°C, field-dependent susceptibility, low Δ<i>T</i>_<i>C</i>, and positive A40 values, indicating juvenile compositions and minimal alteration. Oblique magnetic foliation and steep lineation from in-phase anisotropy of magnetic susceptibility define an upward flow fabric consistent with a feeder dike. In contrast, lapilli and scoria show multiple Curie temperatures between 400° and 570°C, strongly negative Δ<i>T</i>_<i>C</i> and A40, and frequency-dependent susceptibility, reflecting rapid quenching and progressive maghemitization. Hydrothermally altered basalts exhibit Curie temperatures between 440° and 520°C and lower negative Δ<i>T</i>_<i>C</i>, suggesting late-stage reducing fluids. Chemical remanent magnetization due to maghemitization in the lapilli parallels original thermal remanent magnetization in basalt. Reverse polarity and moderate to steep inclinations across all lithologies indicate monogenetic emplacement older than 0.78 million years. The transition from fresh titanomagnetite to maghemitized, hydrothermally overprinted titanomaghemite records a complete sequence from magma ascent to post-eruptive alteration. Out-of-phase magnetic susceptibility measured at different temperatures proves a sensitive proxy for distinguishing primary magmatic signals from secondary overprints in maar-diatreme systems.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JB033665","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148848801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shaking-Induced Small Seismic Velocity Changes as Revealed From Seismic Interferometry Analysis of Distributed Acoustic Sensing Data","authors":"Takashi Hirose,&nbsp;Takeshi Nishimura,&nbsp;Hisashi Nakahara,&nbsp;Kimiko Taguchi,&nbsp;Haruhisa Nakamichi,&nbsp;Kentaro Emoto,&nbsp;Satoru Hamanaka","doi":"10.1029/2025JB031867","DOIUrl":"https://doi.org/10.1029/2025JB031867","url":null,"abstract":"<p>Understanding the spatio-temporal variations in the physical properties of the Earth's crust is crucial for comprehending the dynamic processes linked to earthquakes. Conventional seismometer-based analyses have limitations in spatio-temporal resolution due to the sparse station distribution. Using seismic interferometry with distributed acoustic sensing (DAS), we mapped coseismic velocity changes associated with a M4.1 earthquake 40 km away from Sakurajima volcano, Japan, with high spatial resolution. We observed velocity decreases of up to 1.0% in the 2–3 Hz band in sedimentary or old lava regions with low S-wave velocity, demonstrating enhanced sensitivity of unconsolidated materials to seismic perturbation. By stacking seismic ambient noise cross-correlation functions (CCFs) from many channel pairs, we improved the signal-to-noise ratio sufficiently to estimate relative velocity changes with a temporal resolution of 30 min. Although peak ground velocities observed at seismic stations are one-tenth (0.16 cm/s) of previous studies, we observed comparable seismic velocity reductions and recovery rates until approximately 12 hr after the earthquake. Since DAS can provide dense measurements along fiber-optic cables, it offers new opportunities to investigate seismic velocity changes with high spatial detail and, through stacking seismic ambient noise CCFs from many channel pairs, improved temporal resolution.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 8","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JB031867","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148785116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}