Journal of Geophysical Research: Solid Earth最新文献

{"title":"Softening and Recovery of Near-Surface Layers During the 2024 M7.6 Noto Earthquake","authors":"Miroslav Hallo,&nbsp;Kimiyuki Asano,&nbsp;Tomotaka Iwata","doi":"10.1029/2024JB029961","DOIUrl":"https://doi.org/10.1029/2024JB029961","url":null,"abstract":"<p>On 1 January 2024, a devastating <i>M</i>_<i>J</i> 7.6 earthquake occurred on the Noto Peninsula in Japan. When such a strong earthquake occurs, affected near-surface soil layers behave nonlinearly and may undergo some structural changes driven by Flow Liquefaction, Cyclic Mobility, or Slow Dynamics phenomena. The structural changes can be manifested by short-lasting coseismic and long-lasting postseismic site-response changes that are related to variations in near-surface shear-wave velocity. To examine this behavior, we perform a systematic analysis of Horizontal-to-Vertical (H/V) spectral ratios from regional earthquake waveforms recorded at 160 sites in the years 1996–2024. We identify significant H/V peaks and their directionality in the frequency range of 0.1–25 Hz separately for periods before and after the <i>M</i>_<i>J</i> 7.6 earthquake. This allows us to measure long-lasting relative changes in predominant frequency caused by the strong shaking, with maximum drops of −21% and a dependence on experienced ground motion levels. Next, the short-lasting changes during the <i>M</i>_<i>J</i> 7.6 earthquake reveal strongly nonstationary behavior. The frequency of spectral peaks decreases simultaneously and omnidirectionally with the strong shaking and then logarithmically recovers. The observed extreme short-lasting predominant frequency drops reach −93% relative to the initial value, and their occurrence time divides the nonstationary behavior into elastic softening and recovery phases. This behavior is physically related to temporal changes in near-surface shear-wave velocity as a consequence of changes in shear moduli. The introduced phenomenon of elastic softening and recovery may have a significant impact on a broad scale of geophysical research topics.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143824640","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":"Modelling Partial Melting in Sinking Greenstone Belts With Implications for Archaean Continental Crust Formation","authors":"Guangyu Huang,&nbsp;Ross N. Mitchell,&nbsp;Richard M. Palin,&nbsp;Mingguo Zhai,&nbsp;Richard W. White,&nbsp;Christopher J. Spencer,&nbsp;Jinghui Guo","doi":"10.1029/2024JB030204","DOIUrl":"https://doi.org/10.1029/2024JB030204","url":null,"abstract":"<p>Tonalite–trondhjemite–granodiorite (TTG) gneisses are the dominant component of Archaean continental crust, with their parent magmas generally thought to have formed due to the partial melting of hydrated basalts; however, this process typically produces melts with a notably lower Mg^# than most natural TTGs. By contrast, ultramafic volcanic rocks commonly preserved in Archaean greenstone belts may represent an alternative source of TTG magma that has been largely overlooked. Here, we use petrological modelling to investigate anatexis of komatiites and komatiitic basalts from the Warrawoona Group of the Pilbara craton. In all cases, komatiite is refractory and generates no melt within the pressure-temperature range considered. Komatiitic basalts, however, could produce 20–25 vol. % of MgO-rich melts during greenstone belt sinking and hot subduction. Anatexis of komatiitic basalts generates melt fractions too depleted in large ion lithophile elements to represent natural TTGs; however, hybridization of melts produced by partial melting of tholeiitic basalts and komatiitic basalts during crustal overturn would generate magma that resembles natural TTGs. All calculated melts are felsic in composition, and TTGs with high Mg^# could have been generated entirely within the crust, with no requirement for the assimilation of mantle materials. By contrast, Archaean sanukitoids require some assimilation of mantle materials with crustal melts, indicating that the oldest sanukitoids preserved in each Archaean craton may record temporary and localized subduction on the early earth. The ubiquitous occurrence of sanukitoids worldwide by <i>c</i>. 2.7 Ga may provide a minimum age for the onset of global plate tectonics.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143818586","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":"Earth's Deep-Time Geodynamic Evolution Recorded by Hafnium Isotope Perturbations","authors":"Zhen-Jie Zhang,&nbsp;Timothy Kusky,&nbsp;Guo-Xiong Chen,&nbsp;Qiu-Ming Cheng","doi":"10.1029/2025JB031150","DOIUrl":"https://doi.org/10.1029/2025JB031150","url":null,"abstract":"<p>Interactions between Earth's mantle and crust have shaped the planet's evolution through deep time. Hafnium (Hf) isotopes provide a unique fingerprint of magma sources, enabling the tracking of the crucial interaction zone in the upper mantle evolution through more than four billion years of Earth's history. However, previous studies have relied on a combination of evolved and juvenile zircons, making it challenging to distinguish the genuine evolution of mantle properties. Here, we present a global compilation of Hf isotopic analyses of zircons from juvenile crust to track the upper mantle's evolution throughout Earth's history. By employing Singular Spectrum Analysis and Wavelet Analysis for time series, we decompose the complex Hf isotopic evolution curves and determine the respective periods and interpretations of each component. Our analysis reveals a complex and dynamic evolution of the upper mantle, with distinct periods of stability and upheaval. We show that the upper mantle has undergone periodic perturbations through mixing with crustal materials since Earth's formation, primarily caused by plate subduction and weakly influenced by mantle convective cycles. Hf isotopes reveal vigorous mantle convection that propelled plate tectonics during the Hadean, along with numerous supercontinent cycles that originated in the early Mesoarchean and a notable shift in subduction modes during the Neoproterozoic. This Hf isotope survey provides new insights into Earth's tectonic machinery, advancing our understanding of the planet's geological history.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143818729","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":"Investigation of Submarine Permafrost Conditions in the Canadian Beaufort Sea Using Diving Wave Tomography","authors":"H. Grob,&nbsp;D. Klaeschen,&nbsp;M. Riedel,&nbsp;S. Krastel,&nbsp;M. J. Duchesne,&nbsp;J. Bustamante,&nbsp;G. Fabien-Ouellet,&nbsp;Y. K. Jin,&nbsp;J. K. Hong","doi":"10.1029/2024JB029955","DOIUrl":"https://doi.org/10.1029/2024JB029955","url":null,"abstract":"<p>Submarine permafrost in the Canadian Beaufort Sea is relict terrestrial permafrost, which is continuously degrading since the change of thermal conditions induced by a marine transgression that followed the last glaciation. Permafrost degradation has a crucial socio-ecological significance because its thawing can result in geohazards like landslides or an increase in greenhouse gas emissions. These consequences are mostly regulated by the state of ice in permafrost. In this study, we use marine multichannel seismic data to apply a diving wave tomographic inversion on the outer 50 km of the Canadian Beaufort Shelf. Due to the close relationship between seismic velocity and ice content, we are able to infer detailed information about the present submarine permafrost condition. We find a clear variability of permafrost occurrences between the inner and outer Canadian Beaufort Shelf. At the inner shelf, discontinuous ice-bonding permafrost occurs extensively close to the seafloor but is interrupted by taliks. Within the outer ∼27 km of the shelf, ice-bonding permafrost is absent in the upper sediments and its top has plunged to &gt;200 m below sea level. These findings add new details to the current state of the degrading permafrost. In addition, we observe seismic anisotropy in the frozen permafrost sediments.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB029955","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143818726","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":"The Role of Microcontinent Strength and Basal Detachment in Accretionary Orogenesis: Insights From Numerical Models","authors":"Zoltan Erdős,&nbsp;Susanne J. H. Buiter,&nbsp;Joya Tetreault","doi":"10.1029/2024JB029509","DOIUrl":"https://doi.org/10.1029/2024JB029509","url":null,"abstract":"<p>During closure of an ocean through subduction and continental collision, bathymetric highs such as microcontinents can accrete, collide, or partially or completely subduct. Such interaction of future allochthonous terranes (FATs) with the overriding continent will modify the dynamics of the subduction zone, affecting its length and frictional resistance, and thus the force balance of the subduction system. Accreted microcontinents and microcontinental fragments are preserved in backarcs and collisional orogens, demonstrating that multiple terranes can accrete during a single Wilson-cycle, in what is termed accretionary orogenesis. In this study, we use thermo-mechanical numerical experiments of microcontinent-continent collision events to investigate parameters that influence whether microcontinents accrete, subduct, or collide. Our results indicate that multiple accretionary episodes are possible, but that a weak basal detachment layer within each FAT is paramount for such a scenario to occur. The introduction of a microcontinent, or FAT, in the subduction zone will affect the balance between slab-pull, far-field forces, and the subduction interface resistance. The strength (and rheological stratification) of the microcontinent determines the evolution of the subduction interface resistance throughout the collision event, exerting a first order control on the resulting geodynamic scenario. Collision with a strong microcontinent significantly increases the subduction interface resistance promoting terrane subduction and localization of deformation away from the subduction interface. In turn, collision with a weak microcontinent increases subduction interface resistance only mildly, allowing for multiple accretion events.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB029509","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143818728","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":"Quantifying Localized and Delocalized Rock Deformation in Multi-Stage Relaxation Experiments Using Distributed Optical Fiber Sensing","authors":"Shuting Miao,&nbsp;Arno Zang,&nbsp;Pengzhi Pan,&nbsp;Yinlin Ji,&nbsp;Erik Rybacki,&nbsp;Hannes Hofmann,&nbsp;Guido Blöcher,&nbsp;Martin Lipus","doi":"10.1029/2024JB029881","DOIUrl":"https://doi.org/10.1029/2024JB029881","url":null,"abstract":"<p>Multi-stage uniaxial and triaxial stress relaxation tests were performed on Weschnitz granodiorite, Beishan granite, and Jinping dolomite marble to investigate the deformation evolution before system-size failure, and to study stress relaxation responses. Optical fiber sensing was used to measure distributed strain for full-field strain reconstruction across the sample surface. Strain heterogeneities due to imperfect boundary conditions are detected before and during the linear elastic deformation phase in all samples. The initial strain heterogeneity in the elastic phase is found to control the subsequent inelastic strain localization in granodiorite and granite samples. Macroscopic brittle splitting or faulting in granitic samples eventually occurs within or at the boundaries of the strain localization zones. In contrast, dolomite marble has a more homogeneous strain distribution, with increased differential stress promoting strain delocalization. The reduced axial strain rates during stress relaxation promote time-dependent deformation mechanisms, leading to different spatial distributions of strains. Stress relaxation does not significantly change the degree of strain localization in granite, but it promotes strain delocalization in marble after the onset of dilatancy. In multi-stage tests, inelastic strain accumulates mainly during stress relaxation in granite samples and during stress ramping in marble samples. The different strain distributions and relaxation responses between rock samples result from different deformation mechanisms: localized strain in granite results from clustered microcracking, whereas distributed strain in dolomite marble is driven by both microcracking and low-temperature plasticity (e.g., dislocation glide). These results suggest that lithological differences may result in different precursor signals before system-scale failure and postseismic bulk relaxation responses.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB029881","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143818730","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":"Topographic Drag at the Core-Mantle Interface","authors":"R. Monville,&nbsp;D. Cébron,&nbsp;D. Jault","doi":"10.1029/2024JB029770","DOIUrl":"10.1029/2024JB029770","url":null,"abstract":"<p>The length of day variations with periods from five to one hundred years are mainly due to core-mantle interactions. Assuming a differential velocity between the core and the mantle, we investigate the pressure coupling on a core-mantle boundary (CMB) interface with topography. Including rotation, buoyancy, and magnetic effects in local models of the CMB, we provide a taxonomy of the waves radiated by the core flow along the topography. We obtain the local stress with a perturbation approach and a semi-analytical spectral model built upon these waves. We incorporate planetary curvature effects by considering a “non-traditional” <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>β</mi>\u0000 </mrow>\u0000 <annotation> $beta $</annotation>\u0000 </semantics></math>-plane approximation suited for deep fluid layers and long topography wavelengths. We calculate weakly non-linear flows and characterize the wave drag mechanism. Unlike previous works, our analysis is not restricted to strong stratification or short wavelengths. It reveals the significant impact of the Rossby waves on stress. We also show that these waves are drastically modified when considering two-dimensional topographies instead of simple ridges. For a buoyancy frequency <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>N</mi>\u0000 </mrow>\u0000 <annotation> $N$</annotation>\u0000 </semantics></math> at least comparable to the rotation frequency, the main factors defining the stress are <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>N</mi>\u0000 </mrow>\u0000 <annotation> $N$</annotation>\u0000 </semantics></math> and <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msqrt>\u0000 <msub>\u0000 <mi>U</mi>\u0000 <mn>0</mn>\u0000 </msub>\u0000 </msqrt>\u0000 </mrow>\u0000 <annotation> $sqrt{{U}_{0}}$</annotation>\u0000 </semantics></math> for the small velocity amplitudes <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>U</mi>\u0000 <mn>0</mn>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${U}_{0}$</annotation>\u0000 </semantics></math> relevant for the Earth's core. We document the departures from this scaling law as the velocity is increased. The main part of the CMB pressure torque is due to the topography with the largest horizontal length scale. We calculate the minimum stratification for the topographic torque to produce discernible changes in the length-of-day.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB029770","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143806297","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":"GNSS Observations of the Land Uplift in South Africa: Implications for Water Mass Loss","authors":"Christian A. Mielke,&nbsp;Makan A. Karegar,&nbsp;Helena Gerdener,&nbsp;Jürgen Kusche","doi":"10.1029/2024JB030350","DOIUrl":"https://doi.org/10.1029/2024JB030350","url":null,"abstract":"<p>Continuously operating Global Navigation Satellite System (GNSS) base stations in South Africa show a spatially coherent vertical displacement. While one hypothesis attributes this vertical motion to crustal deformation from mantle flow and dynamic topography (Hammond et al., 2021, https://doi.org/10.1029/2021jb022355), we propose an alternative explanation. Our evidence suggests that land water loss from multiple droughts is a major driver of the observed uplift. In this study, we analyze daily Global Positioning System (GPS) height time series from 2000 to 2021. We use singular spectral analysis (SSA) to separate long-term trends and annual and semi-annual signals from noise. The processed time series were inverted into water mass loading on a uniform grid, with the Earth's crust's rheological properties defined by the Preliminary Reference Earth Model (PREM). Our experimental approach show that a 2<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>°</mo>\u0000 <mo>×</mo>\u0000 </mrow>\u0000 <annotation> ${}^{circ}times $</annotation>\u0000 </semantics></math> 2<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> ${}^{circ}$</annotation>\u0000 </semantics></math> grid resolution provides suitable results for most of South Africa. The GPS-derived total water storage change reconcile well with a GRACE-assimilated solution and a hydrological model at the monthly scale across different provinces, showing correlations of up to 90% and 94%, respectively. The long-term trend averaged over the country shows a considerable correlation of 46% and 53%, respectively. These long-term total water storage trends provide strong evidence that the observed land uplift in South Africa is primarily of hydrological origin.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB030350","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143801811","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":"Mantle Transition Zone-Penetrating Upwellings Beneath the Eastern North American Margin and Beyond","authors":"Yantao Luo,&nbsp;Maureen D. Long,&nbsp;Stéphane Rondenay,&nbsp;Scott D. King,&nbsp;Sarah E. Mazza,&nbsp;Jonathan Wolf","doi":"10.1029/2024JB030005","DOIUrl":"10.1029/2024JB030005","url":null,"abstract":"<p>Low-velocity anomalies in the upper mantle beneath eastern North America, including the Northern Appalachian Anomaly (NAA), the Central Appalachian Anomaly (CAA), and the weaker Southern Coastal Anomaly (SCA), have been characterized by many continent-scale and regional seismic studies. Different models have been proposed to explain their existence beneath the passive margin of eastern North America, variously invoking the past passage of hot spot tracks, modern upwelling due to edge-driven convection, or other processes. Depending on the nature and origin of these anomalies, they may influence, and/or be influenced by, the mantle transition zone (MTZ) structure beneath them. Previous receiver function studies have identified an overall thinner MTZ beneath the eastern margin of the US than beneath the continental interior. In this study, we resolve the MTZ geometry beneath these low-velocity anomalies in unprecedented detail using the scattered wavefield migration technique. We find substantially thinned MTZ beneath the NAA and the CAA, and a moderately thinned MTZ beneath the SCA. In all cases, the thinning is achieved via a minor depression of the 410-km discontinuity and a major uplift of the 660-km discontinuity, which suggests the presence of a series of MTZ-penetrating deep upwellings beneath eastern North America. The upwellings beneath eastern North America and a similar style upwelling beneath Bermuda may initiate from ponded thermally buoyant materials below the MTZ fed by hot return flows from the descending Farallon slab in the deep mantle.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143798044","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":"Role of Crust-Mantle Detachment and Slab Delamination in the Plateau Uplift and Crustal Thickening Process in Southern Tibet","authors":"Zhiqiang Li,&nbsp;You Tian,&nbsp;Dapeng Zhao,&nbsp;Xuan Feng","doi":"10.1029/2024JB029815","DOIUrl":"https://doi.org/10.1029/2024JB029815","url":null,"abstract":"<p>The driving mechanism behind the anomalously thick crust and surface uplift of the Tibetan Plateau remains controversial. Here we present seismic images of the lithosphere in southern Tibet, derived from P and S receiver functions along a newly deployed 200 km-long broadband seismic array that strikes north at 91.15°E longitude. An offset of the Moho discontinuity is revealed at ∼70 km depth beneath the Yarlung-Zangbo suture zone (YZS). The subducted Indian lithospheric mantle is thrusting beneath southern Tibet with a flat-ramp-flat geometry and is undergoing crust-mantle detachment beneath the YZS. As an intermediate stage in the underplating and delamination of the Indian plate, the crust-mantle detachment plays an important role in the process of surface uplift and crustal thickening in southern Tibet. It is the main cause of the Moho offset, facilitating upwelling of asthenospheric materials from the upper mantle to the crust. These materials underplate in the lower crust, promote the formation of juvenile lower crust in southern Tibet, and lead to widespread low-velocity zones within the crust.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 4","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143793764","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}