Journal of Geophysical Research: Solid Earth最新文献

{"title":"Extensive Models for Seismically Viable Inner Core Compositions Featuring Light Element Variations","authors":"Qianxi Chen,&nbsp;Feiwu Zhang,&nbsp;Joshua M. R. Muir","doi":"10.1029/2026JB033776","DOIUrl":"10.1029/2026JB033776","url":null,"abstract":"<p>The composition of Earth's inner core remains unresolved, as pure Fe-Ni alloys cannot fully explain its observed density and seismic wave velocities. While the light elements including hydrogen, carbon, oxygen, sulfur and silicon (H, C, O, S and Si) have been invoked to reconcile these discrepancies, most previous studies have been limited to systems containing one or two light elements, leaving the full range of viable compositions unexplored. We employ ab initio calculations augmented by machine-learned force fields (MLFFs) to systematically investigate the elastic properties of hexagonal-close-packed (hcp)-Fe-light element alloys under inner core conditions. Using a solid solution model parameterized with binary alloy data, we reveal a striking diversity of seismically viable compositions, including previously unrecognized ternary (e.g., Fe-Si-O, Fe-C-H, Fe-O-H) and even senary combinations. This flexibility arises primarily from the strong softening effects of superionic C and O, which dominate elastic behavior despite their low concentrations. While we predict a strict total concentration of the light elements (10–25 mol%), we demonstrate that elasticity alone imposes a much weaker constraint on inner core composition than previously assumed: millions of distinct hcp-Fe-light -element combinations satisfy seismic observations from the Preliminary Reference Earth Model (PREM). This suggests that determining the precise inner core composition must rely more heavily on thermodynamic constraints, as well as independent seismological observations such as partitioning behavior from the outer core, melting relationships, and seismic anisotropy.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 3","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147319809","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":"Limited Passive Lithospheric Underthrusting and Localized Crustal Thickening Beneath the Qilian Shan, Northeastern Tibetan Plateau: Evidence From Receiver Function Imaging","authors":"Yifang Chen,&nbsp;Jiuhui Chen,&nbsp;Yu Li,&nbsp;Panpan Zhao,&nbsp;Biao Guo,&nbsp;Shuncheng Li","doi":"10.1029/2025JB033455","DOIUrl":"10.1029/2025JB033455","url":null,"abstract":"<p>The Qilian Shan, located at the northeastern edge of the Tibetan Plateau (NETP), has undergone complex tectonic evolution and serves as an ideal region for studying the growth of the Tibetan Plateau. However, the mode of lithospheric deformation beneath the Qilian Shan remains a subject of debate. In this study, we use the common conversion point stacking technique with P and S receiver functions, calculated from waveform data recorded by a seismic array consisting of 153 broadband stations, to obtain images of crustal and upper mantle discontinuities beneath the NETP and adjacent Alxa block. Our findings reveal that the Moho depth beneath the NETP is greater than that beneath the Alxa block, with the deepest Moho located beneath the North Qilian area. A sudden decrease of ∼10 km in the Moho depth occurs from the North Qilian fault to the Alxa block. The lithosphere-asthenosphere boundary is clearly identifiable in our data, showing a continuous, southward-dipping interface from the Alxa block to the Qilian Shan. Integrating geophysical and geological results, we propose that passive underthrusting of the Asian Plate occurs beneath the Qilian Shan. This process, influenced by the strong obstruction of the Alxa block during the expansion of the NETP, leads to the accumulation of lithospheric mantle material and crustal thickening and causing the lithospheric mantle of the Asian Plate to bend and undergo southward underthrusting beneath the Qilian Shan.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 3","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147319713","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":"New Insights Into Basal Slip Processes and Kinematics of a Giant Pleistocene Submarine Mass Transport Complex, West of New Zealand's North Island","authors":"Ishika Bhattacharya,&nbsp;Sudipta Sarkar,&nbsp;Utpal Singh,&nbsp;Suzanne Bull,&nbsp;Malcolm Arnot,&nbsp;Jhanvee Khanna","doi":"10.1029/2025JB031830","DOIUrl":"10.1029/2025JB031830","url":null,"abstract":"<p>Submarine landslide runout influences the catastrophic impact of sediment mobilization on seafloor infrastructure, yet the basal slip processes that control runout remain poorly understood due to limited observations. This study examines the evolution and kinematics of a giant Pleistocene Mass Transport Complex (MTC) in the Taranaki Basin, located west of New Zealand's North Island. Using a regional grid of 2D seismic data, we refined its spatial extent and identified four distinct failure sectors (A–D) exhibiting remarkable differences in runout. MTC A, the largest debris flow deposit, covers ∼16,500 km² with a ∼345 km runout. In contrast, MTC D is a frontally emergent slide with a shorter runout of 55 km. A 3D seismic reflection volume reveals MTC D as a coherent, internally faulted slide block showing a frontal ramp, thrusts, pop-up structures, and inverted normal faults. The basal shear surface (BSS) of MTC D lies within a turbidite layer above an earlier MTC. During MTC D sliding, shear softening partially remobilized the underlying MTC, which was subsequently incorporated into the overlying slide block of MTC D. We propose that the remobilized material behaved like a viscous mud, migrating away from high-pressure areas and welding the overlying faulted blocks to the BSS. The resulting high-friction zones at the BSS effectively arrested the movement of MTC D. Our findings present a new conceptual model showing how pre-existing MTCs can influence subsequent sliding processes. This has implications for tsunamigenic hazard assessments, as treating multi-phase failures as single events may overestimate tsunami potential.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 3","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147334699","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":"Deep Learning-Based Tracking of Subduction Zones in Mantle Convection Models","authors":"H. Choi,&nbsp;B. J. Foley","doi":"10.1029/2025JB032355","DOIUrl":"https://doi.org/10.1029/2025JB032355","url":null,"abstract":"<p>Subduction zones are central to Earth's tectonic evolution. Previously, identification and tracking of subduction zones in numerical mantle convection models have relied on methods such as detecting gradients in horizontal surface velocity. However, these approaches require the use of arbitrary thresholds and often lack sufficient spatial context, making robust and consistent detection challenging. This study adapts an established deep-learning workflow for subduction zone (SZ) detection using Fully Convolutional Networks (FCNs), which perform semantic segmentation on RGB images constructed from temperature, vertical velocity, and fineness fields derived from 2D geodynamic simulations. Trained on a curated data set with high-resolution ground truth masks, the FCN effectively identifies SZs with improved spatial coherence and robustness compared to traditional surface velocity convergence methods. Incorporating an attention-based architecture and a custom loss function, the FCN captures complex SZ morphologies, reduces false detections, and enables consistent tracking of SZ evolution over time. Statistical analysis of tracked SZs reveals that those forming near continental margins are longer-lived and less sensitive to mantle convective vigor, while oceanic SZs are shorter-lived and strongly influenced by convective vigor. These findings support the hypothesis that continental lithosphere plays a stabilizing role in early Earth subduction dynamics. This FCN-based method provides a threshold-free, data-driven alternative for SZ detection and offers a powerful tool for analyzing subduction processes in Earth and other planetary interiors.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 2","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JB032355","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147666109","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":"Slowly Migrating Fracture Swarms in an Actively Serpentinizing Borehole","authors":"John M. Aiken,&nbsp;Fabian Barras,&nbsp;François Renard,&nbsp;Greg Hirth,&nbsp;Peter B. Kelemen,&nbsp;Robert A. Sohn","doi":"10.1029/2025JB032133","DOIUrl":"10.1029/2025JB032133","url":null,"abstract":"<p>Peridotite rocks are primary targets for engineered geological carbon sequestration efforts because the carbon in <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mtext>CO</mtext>\u0000 <mn>2</mn>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${text{CO}}_{2}$</annotation>\u0000 </semantics></math>-bearing fluids is transferred to the rock in the form of carbonate minerals during alteration reactions. Sequestration efforts must necessarily open fractures in the rocks surrounding a pumped borehole, but the current understanding of fracture growth during serpentinization of peridotite is limited to theoretical models and laboratory experiments on small samples. We deployed hydrophone arrays in peridotite boreholes established by the Oman Drilling Program and detected downward migrating fracture swarms that represent the first field observations of fracture growth in a serpentinizing rock. More than 2 years after the boreholes were established, we detected four, downward migrating tensile fracture swarms during an interval of elevated pore pressure following large rain events. All of the swarms occurred within a partially confined section of the local aquifer, beginning at a depth of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>170 m and migrating to the bottom of the 400 m-deep hole at average rates of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>6–20 cm.<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>s</mi>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${mathrm{s}}^{-1}$</annotation>\u0000 </semantics></math>. We demonstrate that pore fluid processes can explain both the triggering of the tensile fracture swarms and their slow migration rates. Our results indicate that the tip of fractures propagating away from the borehole maintained near-critical states over time such that relatively small increases in fluid pressure triggered tensile fracturing episodes, indicating that carbon sequestration efforts in mafic rocks should be able to open fractures and expose fresh rock to mineralization.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 2","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JB032133","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147279453","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":"Insights Into the 2020 Instability Crisis of Merapi Through Numerical Modeling","authors":"M. Galárraga,&nbsp;L. Scholtès,&nbsp;B. Chevalier,&nbsp;N. Aisyah,&nbsp;K. Kelfoun","doi":"10.1029/2025JB032728","DOIUrl":"10.1029/2025JB032728","url":null,"abstract":"<p>The northwestern flank of Merapi volcano (Java, Indonesia) moved from July 2020 to January 2021. The cliff collapses at the summit, the size of the affected area (about 500 m in elevation and 1 km wide) and a flank displacement of about 14 m, never observed before, led to fears of a flank collapse. Field observations suggested a correlation between this flank movement and the opening of a NE-SW fracture crossing the entire summit, filled with magma. In the present study, we developed numerical models based on the discrete element method to investigate the role of the NE-SW fracture pressurization on the deformation of Merapi. Even though simplified, considering the complexity of the processes at stake, our approach manages to reproduce the observed deformations both in terms of kinetics and kinematics. Specifically, the model reproduces the inelastic deformation of the northwestern flank to a depth of about 500 m below the summit. Under the pressure of the magma, the northwestern flank tilted slightly, causing its sliding with displacement magnitudes increasing with elevation. As observed on-site, the sliding eventually stopped so that the flank reached a new stable state, demonstrating how topographic readjustments of a volcano, driven by magma pressure, can produce significant plastic deformation without leading to a major flank collapse.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 2","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146231309","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":"Micromagnetic Constraints on the Grain Size Dependence and Magnetic Stability of Sub-Micron Monoclinic Pyrrhotite (Fe7S8)","authors":"Wyn Williams,&nbsp;Adrian R. Muxworthy,&nbsp;Ualisson Donardelli Bellon,&nbsp;Lesleis Nagy,&nbsp;Alison A. Cowan,&nbsp;Miguel A. Valdez-Grijalva,&nbsp;Andrew P. Roberts","doi":"10.1029/2025JB031684","DOIUrl":"10.1029/2025JB031684","url":null,"abstract":"<p>We present the first micromagnetic simulations for sub-micron monoclinic 4C pyrrhotite (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mtext>Fe</mtext>\u0000 <mn>7</mn>\u0000 </msub>\u0000 <msub>\u0000 <mi>S</mi>\u0000 <mn>8</mn>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${text{Fe}}_{7}{mathrm{S}}_{8}$</annotation>\u0000 </semantics></math>), a common mineral in rocks and sediments and an important mineral in paleomagnetic studies. Previous experimental studies on the magnetic properties of pyrrhotite had limited control over granulometry and focused primarily on larger, micron-scale grain sizes. We model <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mtext>Fe</mtext>\u0000 <mn>7</mn>\u0000 </msub>\u0000 <msub>\u0000 <mi>S</mi>\u0000 <mn>8</mn>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${text{Fe}}_{7}{mathrm{S}}_{8}$</annotation>\u0000 </semantics></math> particles here with a hexagonal prismatic habit and uniaxial and triaxial basal plane anisotropy in the 5 nm to <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>2</mn>\u0000 <mspace></mspace>\u0000 <mi>μ</mi>\u0000 <mi>m</mi>\u0000 </mrow>\u0000 <annotation> $2hspace*{.5em}{upmu }mathrm{m}$</annotation>\u0000 </semantics></math> range. Single domain (SD) structures remain the lowest energy state for particles up to ≈2 μm in size, although it is possible to nucleate multidomain (MD) states in particles as small as 100 nm. MD structures consist of domains aligned within the basal plane separated by Néel walls, often with internal Néel lines; no vortex states are observed. In hysteresis and first-order reversal curve simulations, sub-micron pyrrhotite particle magnetizations switch coherently, giving rise to uniaxial-SD signatures within the basal (001) plane; triaxial switching is not observed because the field step used in our models is too large to visualize the expected signals. Estimated relaxation times predict that hexagonal monoclinic pyrrhotite prisms have a ≈15 nm superparamagnetic threshold size and are geologically stable at sizes above≈20 nm. We find generally good agreement between experimental data and numerical predictions that assume uniaxial basal plane anisotropy, although there is little grain-size overlap between the two data types, and questions remain regarding the accuracy of experimentally observed material parameters for pyrrhotite.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 2","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JB031684","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146778406","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":"Stress and Deformation Characteristics of the Central-Southern Tibetan Crust: Insights From Electrical Anisotropy Studies","authors":"Zhehan Liu,&nbsp;Hao Dong,&nbsp;Sheng Jin,&nbsp;Wenbo Wei,&nbsp;Gaofeng Ye,&nbsp;Letian Zhang","doi":"10.1029/2024JB030594","DOIUrl":"10.1029/2024JB030594","url":null,"abstract":"<p>Mechanisms governing the stress-induced surface deformation of the Tibetan Plateau and other continental collision zones remain vigorously debated in the geoscience community. Crustal rheological properties can offer valuable insights into the Earth's deformation patterns. Here, we present an electrical anisotropic study of the crust and upper mantle along a profile in the central-southern Tibetan Plateau. Our resistivity models unveil a large-scale conductive layer beneath the study region, with distinct electric anisotropic orientations within the middle and lower crust. The middle crust exhibits nearly north–south (N–S) directed anisotropy features, whereas the lower crust anisotropy axis is east–west (E–W) directed. From the conductivity model, we estimate the melt fraction and viscosity distribution using an experiment-based empirical formulation. As demonstrated by the petrological experiments, the amphibole-rich mid-to-lower crust could host the aligned fractures/microcracks and melt pockets, possibly facilitating the observed anisotropy. With an anisotropic conduction model, we also show that the distribution characteristics of these cracks and pockets may directly influence the effective conductivity. The two-layered electrical anisotropy observed likely reflects distinct deformation types and rheological strengths: the N–S electrical anisotropy may originate from fluid-filled fractures from the brittle deformation in the middle, while the E–W anisotropy may arise from the deformed conductive melt pockets in the ductile lower crust. These findings may provide a novel way to characterize the crustal deformation mechanisms using geo-electrical anisotropy, in other tectonically active regions.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 2","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146223341","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":"Chemical-Thermomechanical Modeling of Open-System Mass Transfer: Application to the Subduction Interface","authors":"Jun Ren,&nbsp;Manuele Faccenda,&nbsp;Xin Zhong,&nbsp;Matthieu E. Galvez,&nbsp;Jianfeng Yang,&nbsp;Nicolas Riel","doi":"10.1029/2025JB032901","DOIUrl":"10.1029/2025JB032901","url":null,"abstract":"<p>One of the main limitations in simulating subsolidus metasomatism is the decoupling between thermomechanical models and chemical/thermodynamic modeling. This decoupling amplifies the uncertainty associated with mass transport. Here, we introduce a fluid-rock chemical-thermomechanical interaction scheme, which integrates thermodynamic modeling (via the Backcalc algorithm and MAGEMin software) into a 2D thermomechanical code. This approach enables us to track the fate of multicomponent slab-derived metamorphic fluids and the resultant spatially heterogeneous geochemical signatures at the slab-mantle interface (SMI). Our modeling results show that slab-derived nonvolatile element fluxes (i.e., Si, Al, Ca) are predominantly precipitated right above the SMI, forming a highly altered layer where fluid availability and element mobility promote the development of mineral zonation. A similar phenomenon also occurs within mélange zones wherever sharp chemical gradients are present. This indicates that nonvolatile element accumulation is not tied to a specific location, but rather to chemical contrasts, which is consistent with field observations. Additionally, advective transport of solid rock is found to be at least two orders of magnitude more efficient than fluid infiltration in the redistribution of mass from slab to mélange zones, further promoting the chemical complexity of mélange zones. Overall, this new tool offers a promising platform for improving our understanding of the interplay between rock chemistry and mechanics, chemical budgets, and magmatism at convergent margins.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 2","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JB032901","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146778840","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":"Global Imaging of the Mantle Transition Zone Using SS Precursors Shows Lower Mantle Convection Patterns that are Broadly Linked to Tectonics","authors":"Yuhang Dai,&nbsp;Catherine Rychert,&nbsp;Nicholas Harmon","doi":"10.1029/2025JB032278","DOIUrl":"10.1029/2025JB032278","url":null,"abstract":"<p>Central to our understanding of mantle convection and inner Earth material transport is the mantle transition zone. Mantle transition zone thicknesses can reveal key constraints on the locations and degree of material transport between the upper mantle and lower mantle. Therefore, it's essential for our knowledge of geochemical reservoirs, hydration cycles, and the evolution of the Earth. We use SS precursors to image the mantle transition zone discontinuities using a newly developed method and seismic data from 1990–2021, providing excellent global data coverage. We also test a variety of different migration models. The major features are robust regardless of the choice of migration model. We find a thickened mantle transition zone (by 5–20 km) beneath subduction zones, coincident with the locations of high-velocity anomalies from tomography models. The mantle transition zone is thinned by 5–10 km beneath oceans, although thinning is not necessarily focused beneath hotspot regions. The thinning and thickening also correspond to shear velocity anomalies that would be predicted for thermal perturbations. The 660 topographies are generally consistent with mantle transition zone thickness variations, whereas the 410 topographies do not show relationships with mantle transition zone thickness. This is likely because convection processes are more complex than simple vertical upwelling at hotspots and downwelling at subduction zones, and/or because material transfer at the 410 occurs at smaller lateral scales than resolved by our study.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 2","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JB032278","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146261147","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}