Journal of Geophysical Research: Solid Earth最新文献

{"title":"Distinct Groundwater Regimes in West Antarctic Sedimentary Basins Inferred From Magnetotelluric Imaging","authors":"Siobhan F. Killingbeck,&nbsp;Bernd Kulessa,&nbsp;Rebecca Pearce,&nbsp;Alex Brisbourne,&nbsp;Louise Borthwick,&nbsp;Felipe Napoleoni,&nbsp;Sridhar Anandakrishnan,&nbsp;Martyn Unsworth,&nbsp;Atsuhiro Muto","doi":"10.1029/2026JB033859","DOIUrl":"10.1029/2026JB033859","url":null,"abstract":"<p>Subglacial sedimentary basins in Antarctica are hypothesized to modulate ice flow and biogeochemical cycles via groundwater and geothermal feedbacks, yet their properties remain poorly constrained. Here, we present a joint quantitative analysis of new magnetotelluric (MT) data acquired at Thwaites Glacier (TG) and WAIS Divide, alongside legacy data sets from Whillans Ice Stream, Ross Ice Shelf, and South Pole. The new MT data reveal a shallow 1-D crustal structure, around the ice bed interface, at TG, overlying deeper 3-D structures. Our constrained 1-D transdimensional Bayesian inversion of the upper crust highlights that the sedimentary basin beneath TG exhibits relatively high resistivity (&gt;10 Ωm), distinct from the lower-resistivity (&lt;10 Ωm) basins at other sites. Sensitivity analysis reveals that the TG basin is horizontally heterogeneous, with conductive signatures in thicker sections and resistive signatures at GHOST Ridge, a subglacial topographic high which has been identified as a potential future stabilizing point. Conversely, basins beneath Subglacial Lake Whillans and the South Pole exhibit vertical stratification, with relatively resistive upper layers, up to 600 m thick, above conductive deeper layers (&lt;5 Ωm). We hypothesize that complex, spatially variable groundwater regimes are widespread in Antarctica. These contrasting hydrological environments imply continent-scale variability in subglacial thermodynamics and possible modulation of inherent ice dynamics.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JB033859","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148895253","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":"Seismic Evidence for Hydration of the Mantle Transition Zone Beneath Tibet and Its Implications for Water-Rich Mantle Upwelling","authors":"Yibin Wu,&nbsp;Xiaobo Tian,&nbsp;Xiaofeng Liang,&nbsp;Yibing Li,&nbsp;Xiaobo He","doi":"10.1029/2026JB033948","DOIUrl":"10.1029/2026JB033948","url":null,"abstract":"<p>Seismic studies have suggested widespread thickening of the mantle transition zone (MTZ) beneath the Tibetan Plateau, which is commonly attributed to the foundering of cold lithosphere. However, the spatial pattern of MTZ thickening does not consistently align with the distribution of high-velocity anomalies, suggesting that other factors, such as hydration, also influence MTZ structure. In this study, we employ a dense broadband seismic array combined with existing regional deployments to obtain improved receiver function images of the MTZ beneath Tibet. After correcting for upper mantle heterogeneity using a recent high resolution tomographic model, we combine MTZ thickness anomalies with mean S-wave velocity perturbations to quantify lateral variations in temperature and water content. Our results show that the MTZ beneath the plateau contains on average at least 0.31 wt.% H₂O and is underlain by a low-velocity layer (LVL) immediately above the 410-km discontinuity. These features exhibit a pronounced north-south asymmetry: the northern MTZ is relative warm and water-rich, whereas the southern MTZ is cooler and drier but overlain by a more extensive LVL. We propose that piece of cold lithosphere sank into the southern MTZ has displaced water-rich mantle material from the MTZ into the upper mantle, leading to dehydration above the MTZ, formation of the LVL, and giving rise to a water-rich mantle upwelling. These processes likely played a key role in generating Miocene porphyry copper deposits in the southern Tibetan Plateau.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148895262","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":"Probing the Elastic Anisotropy of Schistose Rocks West of the Tauern Window (Eastern Alps, Austria): The Largest Homogeneous Volume","authors":"D. Lang,&nbsp;R. Kuehn,&nbsp;R. Kilian,&nbsp;H. Pomella,&nbsp;M. Stipp","doi":"10.1029/2025JB033743","DOIUrl":"10.1029/2025JB033743","url":null,"abstract":"<p>The anatomy of orogens is difficult to decipher as structural information is usually limited to surface and seismic data. Seismic properties are directionally dependent on anisotropic minerals, especially phyllosilicates. Due to tectonic complexity, the effect of anisotropy in seismic data is difficult to determine. Here, we present an approach to determine the anisotropy in representative volumes of deformed phyllosilicate-rich rocks at the margin of the Tauern Window in the European Alps. Samples from the northern half of the Brenner Base Tunnel were selected within the lithotectonic units Innsbruck Quartzphyllite, Matrei Zone and Bündner schists. Microstructure types were determined by optical microscopy. In order to determine the largest non-folded volume within phyllosilicate-rich layers, the crystallographic preferred orientations (CPOs) in millimeter-thick cylinders were measured using synchrotron X-ray diffraction. Seismic velocities were computed by using compositional data, single crystal stiffness tensors and the measured CPO. Based on the largest homogeneous–microstructurally undisturbed–volume, an upper bound for a non-folded state of the velocity anisotropy was estimated. The P-wave anisotropy varies from 6% to 17%, while the maximum shear wave splitting varies from 0.2 to 0.7 km/s. Fast and slow velocity directions are parallel and perpendicular to the foliation, respectively. Hence, the anisotropy depends on phyllosilicate content and CPO, while other rock-forming minerals of the crust are largely irrelevant for the elastic anisotropy of schists. Microstructural deviations from planar fabrics lead to a decrease in CPO and anisotropy. These findings need to be considered for the geotectonic interpretation of seismic cross sections in orogens.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JB033743","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148895263","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":"Water Percolation Threshold in Porous Media Modulated by Geometry and Interfacial Physics","authors":"Zhenqi Guo,&nbsp;Beichen Ji,&nbsp;Feiyan Jin,&nbsp;Xiangbo Gao,&nbsp;Lei Liu,&nbsp;Shengjie Hu,&nbsp;Tingchang Yin,&nbsp;Sergio Andres Galindo Torres,&nbsp;Herbert E. Huppert,&nbsp;Liang Lei","doi":"10.1029/2026JB034791","DOIUrl":"10.1029/2026JB034791","url":null,"abstract":"<p>Water percolation threshold in porous media marks the critical saturation where fluid transitions from isolated ganglia to a full-scale cluster, essential for understanding transport in porous media. This onset of connectivity is crucial for fluid transport in natural and artificial porous systems such as hydrocarbon reservoirs, electrodes, and membranes. Traditionally, determining this threshold relies primarily on laboratory experiments and empirical curve fitting. Percolation theory offers a theoretical foundation for locating this threshold in an ideal, randomly occupied, and infinite system. However, real porous media deviate from these assumptions: (a) water-phase connectivity is restricted within pore space as a subdomain of the full 3D space, and (b) even under static or quasi-static conditions when dynamic flow or the invasion process is neglected, fluid occupancy departs from ideal random occupation because of pore geometry, wettability, and capillary constraints. Here, we employ Monte Carlo simulations to assess porosity and geometrical effects on thresholds under random occupancy. We find that restricting connectivity to the pore space of a porous structure, instead of the full 3D space, increases the threshold relative to classical random-occupation models. Based on physically constrained fluid configurations, we then simplify the porous media into basic units, each containing a single meniscus, and derive the lower and upper bounds for the water-phase connectivity threshold as a function of wettability and meniscus coordination number. Statistical analyses based on X-ray micro-CT data sets and pore-scale observations support these bounds. This study offers new physical insight into the critical saturation required for connectivity in porous media.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148895255","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":"Characterizing Shallow Attenuation and Microearthquake Source Parameters Using a Downhole DAS Array at the Cape Modern Geothermal Field","authors":"Hilary Chang,&nbsp;Nori Nakata,&nbsp;Rachel E. Abercrombie,&nbsp;Sireesh Dadi,&nbsp;Aleksei Titov","doi":"10.1029/2026JB034276","DOIUrl":"10.1029/2026JB034276","url":null,"abstract":"<p>Earthquake source parameters are crucial for assessing seismic hazard and understanding earthquake source physics. However, source parameter estimation is challenging for small earthquakes because they suffer notorious trade-offs with shallow attenuation. Borehole Distributed Acoustic Sensing (DAS) uses fiber-optic cables to provide unprecedented spatial resolution for attenuation analysis and a closer recording of the earthquake source. In this study, we use DAS in a vertical well in the Cape Modern geothermal field, near Milford, Utah, to characterize shallow attenuation and estimate source parameters of microearthquakes <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>(</mo>\u0000 <mrow>\u0000 <mn>0</mn>\u0000 <mo>&lt;</mo>\u0000 <mi>M</mi>\u0000 <mo>&lt;</mo>\u0000 <mn>1.7</mn>\u0000 </mrow>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 <annotation> $(0&lt; M&lt; 1.7)$</annotation>\u0000 </semantics></math> that occurred during a stimulation. We directly correct the DAS instrument response and directional sensitivity. We use along-depth spectral ratios to obtain a high-resolution Quality Factor (<i>Q</i>) profile for P waves in the top 2,500 m. We find low <i>Q</i> at the near surface, and that attenuation primarily decreases with depth, with less dependence on rock types, consistent with previous studies in California and Switzerland. We use a single-spectral approach to estimate corner frequency, source radius, slip, magnitude, and spectral stress drop over the limited magnitude range. The spectral stress drops do not show magnitude dependence, while their variability might relate to fault heterogeneity or rupture variability. The DAS response-correction is channel-dependent and can introduce biases in source parameters. We reduce potential biases by using channels with similar responses and checking measurement consistency. We use the Empirical Green's Function for two event pairs to benchmark the results. This work shows the potential of using DAS for understanding crustal attenuation and characterizing microearthquakes.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JB034276","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148895259","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":"Fully Contained Laboratory Earthquakes: The Effect of Asperity Aspect Ratio and Free Surfaces","authors":"Sara B. L. Cebry,&nbsp;Jun Young Song,&nbsp;Gregory C. McLaskey","doi":"10.1029/2025JB033548","DOIUrl":"10.1029/2025JB033548","url":null,"abstract":"<p>Corner frequency (<i>f</i>_<i>c</i>) and seismic moment (<i>M</i>_<i>0</i>) are key parameters derived from seismic signals that are used to characterize earthquake stress drop, rupture area, and slip. These parameters are also affected by fault geometry and boundary conditions. However, the systematic study of these effects in laboratory settings has been challenging. This study presents laboratory earthquake experiments that examine how rupture dynamics are influenced by (a) the aspect ratio of rectangular PMMA velocity-weakening (VW) asperities surrounded by the Teflon velocity-strengthening (VS) patches, and (b) whether the sides of a VW asperity are confined with VS patches or are free surfaces. We found that increasing confinement by reducing free surfaces or increasing the VW asperity aspect ratio stabilizes fault slip, so that higher normal stress is required to transition from aseismic to seismic slip. Increased confinement and high aspect ratios also reduced <i>M</i>_<i>0</i> and increased <i>f</i>_<i>c</i>, both of which were determined from the radiated seismic waves. <i>M</i>_<i>0</i> and <i>f</i>_<i>c</i> were primarily controlled by the shorter dimension of the VW asperity. Analysis of high-frequency acoustic emission signals revealed that ruptures on high-aspect-ratio VW asperities propagated more unidirectionally, whereas ruptures on square VW asperities were more complex. Further, the high-aspect-ratio asperities were more likely to be eroded by surrounding VS regions while low-aspect-ratio asperities were more likely to rupture into the VS surroundings. These results demonstrate that both the confinement from surrounding stable areas and the geometry of the seismogenic patch can affect rupture nucleation, propagation, and seismic source characteristics.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148895261","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":"Imaging Submarine Fault Zones Using Reflected S-waves Extracted by Ambient Noise Interferometry From Distributed Acoustic Sensing","authors":"Zhufeng Lu,&nbsp;Xiaodong Yang,&nbsp;Heng Zhang,&nbsp;Liwei Wang,&nbsp;Xinghan Liu,&nbsp;Yao Luo,&nbsp;Fan Zhang,&nbsp;Jian Lin,&nbsp;Jianhua Geng,&nbsp;Jizhong Yang","doi":"10.1029/2025JB033370","DOIUrl":"10.1029/2025JB033370","url":null,"abstract":"<p>The northern margin of South China Sea has experienced strong tectonic deformation since the Late Mesozoic, and formed a complex fault network. Along this margin, previous studies have mainly imaged offshore faults in the Shantou region at &gt;30 m water depth. However, the precise fault location and geometry at &lt;30 m water depth (nearshore) are poorly resolved due to lack of geophysical observations, preventing a better assessment of marine geohazards. Here, we retrieve high-resolution zero-offset S-wave reflections from interferometric autocorrelation of ambient noise recorded by Distributed Acoustic Sensing (DAS) along a 29-km submarine cable deployed in the nearshore. The meter-scale reflections delineate stratigraphic boundaries, fault structures, and potential magmatic intrusions, where fault locations are validated by independent constraints including a 2D shear-wave velocity model, spurious energy in the cross-correlation functions, and earthquake wavefield analyses. We precisely locate the nearshore extension of the Changle-Nan'ao Fault and resolve an ∼8-km-wide graben bounded by the Nanpeng Island Outer Fault and a newly mapped fault, beneath the graben the igneous intrusion is identified, indicating strong tectonic and magmatic interaction. This structurally weakened zone has localized extension which may contribute to seafloor instability. By using DAS ambient noise autocorrelation, we successfully retrieved geologically interpretable reflections, demonstrating the potential of using existing fiber-optic cables to provide cost-effective, high-resolution structural constraints in complex tectonic settings.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148895212","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":"Probability and Recurrence of Maximum Magnitude Based on Stochastic Modeling of Internal Fault Geometry","authors":"Vincent Roche,&nbsp;Mirko van der Baan,&nbsp;John Walsh,&nbsp;Tom Manzocchi","doi":"10.1029/2025JB032073","DOIUrl":"10.1029/2025JB032073","url":null,"abstract":"<p>The recognition that relay zones along faults can act as barriers to earthquake propagation implies that rupture size may not be random and earthquakes are constrained by fault geometry. Resolution and observational biases can, however, complicate the integration of actual fault zone geometries into deterministic modeling strategies, thereby negatively impacting earthquake magnitude assessment. This paper describes a statistical modeling strategy as an alternative. The chosen method relies on a stochastic approach combining quantitative fault zone characteristics with a kinematic model linking realistic fault segmentation with expected rupture termination. A sensitivity analysis highlights the effect of fault geometry on rupture sizes, including an increase in the probability of large ruptures, and corresponding changes in the earthquake magnitude-frequency distribution and associated <i>b</i>-values, with decreasing degrees of segmentation and increasing fault maturity. Three case studies confirm these effects for the Yushu-Ganzi-Xianshuihe fault system, the North Anatolian fault system, and hydraulic fracturing in Ohio. For each case, simulations show first-order agreement with documented seismicity, including observed magnitude-frequency distributions, and support the notion that fault characteristics such as relay zone size and internal segmentation are structural controls determining earthquake <i>b</i>-values and maximum magnitudes. These findings suggest that the incorporation of more realistic fault zone geometries and their impact on rupture cascading could improve seismic risk assessment across various regions.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JB032073","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148895258","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":"Pn-Wave Tomography Using Deep-Learning-Based Phase Picking Reveals Fine-Scale Structure of the Uppermost Mantle Beneath the Southwestern United States","authors":"Hua Kong,&nbsp;Yan Lü,&nbsp;Juan Li,&nbsp;Zhuowei Xiao,&nbsp;Lian-Feng Zhao,&nbsp;Lijun Liu","doi":"10.1029/2026JB034108","DOIUrl":"10.1029/2026JB034108","url":null,"abstract":"<p>The southwestern United States, with its intense tectonic activity and dense seismic networks, serves as a natural laboratory for studying crust-mantle material exchange and energy transfer. In recent years, the rapid growth of seismic observational data and the development of deep learning-based automatic phase-picking techniques have provided new opportunities for high-resolution seismic imaging research. This study utilized the Seis-PickNet phase-picking model to expand the Pn-wave travel-time database for the southwestern United States. Based on the newly picked travel times, the study constructed a high-resolution model of the uppermost mantle velocity structure and anisotropy structure in the region. The inversion results show that the spatial distribution of active tectonic units in the area corresponds well to significant low-velocity anomalies and strong anisotropic features in the uppermost mantle. Furthermore, the study reveals independent thermal upwelling conduits in the uppermost mantle beneath volcanic fields along the margins of the Colorado Plateau, including the Black Rock Desert Volcanic Field, the Uinkaret Volcanic Field, and the San Francisco Volcanic Field. Additionally, the results support the existence of ancient Farallon slab subduction remnants beneath the central Great Basin. This research not only deepens the understanding of mantle dynamics and complex subsurface structures in the region but also highlights the critical role of deep learning-driven phase-picking technology in enhancing the quality of seismic tomography.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 9","pages":""},"PeriodicalIF":4.0,"publicationDate":"2026-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148895260","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":"Seismic Velocity of Chlorite Under High Pressure and Temperature and Implications for the Lesser Antilles Subduction Zone","authors":"Nicholas Backhouse,Andrew Thomson,John Brodholt,Rostislav Hrubiak,Wilson Crichton,Ming Hao,Emmanuel A. Codillo,Anne Pommier,Michael J. Walter","doi":"10.1029/2025jb032997","DOIUrl":"https://doi.org/10.1029/2025jb032997","url":null,"abstract":"Abstract Chlorite is thought to be one of the major water‐carrying phases in subduction zones, both within the slab and in the mantle wedge. Its presence has previously been linked to common seismological observations at subduction zones, including P and S wave anisotropy as well as high V P / V S ratios (&gt;1.8) in the mantle wedge. However, at present, there are very few high pressure and temperature measurements of the seismic velocity of chlorite at subduction zone conditions, hampering accurate seismological interpretations. This study presents seismic velocities and PVT equation of state measurements of two natural monomineralic chlorite schists, at conditions extending up to ∼5 GPa and 773K. One major finding is the anomalously high V P / V S ratio of these samples, which increase &gt;3 at 5 GPa and 773 K. This result suggests that only a small amount of chlorite (&lt;10%) is required in mantle peridotite assemblages to reproduce the observed V P / V S anomalies &gt;1.8, such as those in the Lesser Antilles subduction zone, and that regions with high V P / V S are not necessarily diagnostic of a free fluid.","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"17 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148895256","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}