Physics of the Earth and Planetary Interiors最新文献

{"title":"Exceptional secular variation recorded in Neolithic hearths, Orkney and Swedish lake sediments","authors":"Neil Suttie ,&nbsp;Sam Harris ,&nbsp;Catherine M. Batt ,&nbsp;Andreas Nilsson ,&nbsp;Ian Snowball ,&nbsp;Nick Card ,&nbsp;Zoe Outram","doi":"10.1016/j.pepi.2025.107412","DOIUrl":"10.1016/j.pepi.2025.107412","url":null,"abstract":"<div><div>Geomagnetic field models constrained by direct observations extend back some 400 years and the magnitude of decadal to centennial variations that they display is often assumed to be typical of the secular variation over longer timescales. Here we present archaeomagnetic directions from layered Neolithic hearths in Orkney, dating to around 3000 BCE, that challenge this assumption. Combining stratigraphic controls with radiocarbon dates allows for a precise chronology, which, in turn, implies directional change of more than 12°/century lasting for 200 years, far in excess of anything seen at this latitude over the era of historical observations. These archaeomagnetic data are complemented by similarly rapid changes in inclination recorded in two high temporal resolution sediment cores from Kälksjön, Sweden. As well as raising the possibility of using archaeomagnetic dating within this important archaeological period, the new data pose questions regarding our understanding of the secular variation, the limitations of the historic field as a proxy for the past, and the underlying dynamical processes within the core. This research highlights the importance of archaeology to the wider scientific community and the potential of archaeological material to further our understanding of Earth processes.</div></div>","PeriodicalId":54614,"journal":{"name":"Physics of the Earth and Planetary Interiors","volume":"366 ","pages":"Article 107412"},"PeriodicalIF":2.4,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144320824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating seismic crustal anisotropy and sub-crustal deformation beneath Northeast India through harmonic decomposition of receiver functions","authors":"Dhiraj Kumar Singh ,&nbsp;Mohit Agrawal ,&nbsp;Hitank Kasaundhan ,&nbsp;O.P. Mishra ,&nbsp;M.K. Sen","doi":"10.1016/j.pepi.2025.107408","DOIUrl":"10.1016/j.pepi.2025.107408","url":null,"abstract":"<div><div>Northeast India, characterized by its active seismicity, complex tectonic structures, ongoing subduction, and diverse lithological formations, serves as an important natural laboratory for anisotropic studies. This study analyzed lithospheric anisotropy through the Harmonic Decomposition (HD) of receiver functions derived from teleseismic earthquakes recorded at ten broadband seismic stations across the region. Our findings reveal significant variations in crustal deformation across the Eastern Himalayas, Assam Valley, Shillong Plateau, and Bengal Basin, driven by distinct tectonic influences. We observed a Moho depth of approximately 50–60 km in the Indo-Burma and Eastern Himalayan regions, around 30–40 km in the Assam Valley, about 37 km in the Shillong Plateau, and between 43 and 47 km in the Bengal Basin. Further, the alignment of fast anisotropic axes generally follows the motion of the Indian Plate (N20⁰E), with localized deviations near the Kopli Fault and Indo-Burma region, indicating intricate tectonic complexities. However, the anisotropy axis direction varies from N20⁰W to <em>E</em>-W in the uppermost mantle. The adjacent variations in anisotropic interfaces and their tilt axes across these regions reflect extensive crustal deformation associated with subduction and collision tectonics. Notably, the Eastern Himalayas exhibit a lattice-preferred alignment in the <em>E</em>-W direction, while the increasing Moho depth from north to south underscores the effects of ongoing collision and crustal thickening associated with down warping of the mantle, particularly in areas like the Shillong Plateau and Bengal Basin. The simultaneous presence of shallower Moho and stress perpendicular to anisotropic tilt direction (<em>E</em>-W) discerned in this study validates the hypothesis of a tectonically supported uplifted Shillong Plateau. These findings highlight the role of asthenosphere flow and transpressional thickening in shaping the crustal structure in the Indo-Burma ranges due to sub-crustal geodynamical processes, with additional influences from subsidence and sediment deposition in the Bengal Basin. The observed anisotropy is consistent with past Indian plate motion, while variations in the Tripura fold belt suggest complex interactions between mantle flow and regional tectonics.</div></div>","PeriodicalId":54614,"journal":{"name":"Physics of the Earth and Planetary Interiors","volume":"366 ","pages":"Article 107408"},"PeriodicalIF":2.4,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144330290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The source process of the 2014 Jinggu earthquake in Yunnan, China","authors":"Junlei Chen ,&nbsp;Yan Li ,&nbsp;Jinlai Hao ,&nbsp;Tao Xu","doi":"10.1016/j.pepi.2025.107410","DOIUrl":"10.1016/j.pepi.2025.107410","url":null,"abstract":"<div><div>The 2014 Jinggu <em>M</em>_w 6.0 earthquake occurred in the complex conjugate fault system of the Southwest Yunnan Block, comprised of NNW-trending and NNE-trending faults. We relocated the mainshock's hypocenter and inverted the focal mechanisms of earthquakes greater than <em>M</em> 3.5 and the mainshock's rupture process to study the earthquake sequence's source process. The relocation of the mainshock's hypocenter was determined to be at 100.47°E, 23.40°N, and 9.3 km. The focal mechanism of the mainshock is 150°/76°/179°(strike/dip/rake). There are 21 strike-slip earthquakes, 2 normal aftershocks, and 2 thrust aftershocks. The average dip angle of the Jinggu earthquake sequence is 78.75°. The Jinggu earthquake was a single-fault bilateral rupture event. The peak slip, average rake, and slip rate of the mainshock are 0.56 m, 182°, and 2.12 km/s, respectively. The main slip patch of the mainshock slip model was at 4 km in the 150° direction from the epicenter with a depth ranging from 4 km to 9 km. Ninety percent of the energy was released within the first 5.8 s. The Jinggu earthquake sequence may consist of ruptures on two fault planes dominated by the mainshock and two <em>M</em>_w 5.5 aftershocks occurring within the conjugate fault system.</div></div>","PeriodicalId":54614,"journal":{"name":"Physics of the Earth and Planetary Interiors","volume":"366 ","pages":"Article 107410"},"PeriodicalIF":2.4,"publicationDate":"2025-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144312683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Surface wave attenuation beneath the Himalaya-Tibet region constrained by fundamental mode of Rayleigh wave from the Hi-CLIMB dataset","authors":"Davin David ,&nbsp;Utpal Saikia ,&nbsp;Ritima Das ,&nbsp;Sarmistha Bhagawati","doi":"10.1016/j.pepi.2025.107404","DOIUrl":"10.1016/j.pepi.2025.107404","url":null,"abstract":"<div><div>This study investigates Rayleigh wave group velocity and surface wave attenuation coefficients in the Himalaya-Tibet region using seismograms from 16 earthquakes recorded along the Hi-CLIMB network. The observed amplitude variations reveal a decreasing trend with distance, attributed to geometrical spreading, source radiation, wavefield scattering, and intrinsic attenuation. Attenuation coefficients range from 0.00167 km⁻¹ to 0.00039 km⁻¹ across the study area, while Rayleigh wave group velocities vary from 2.5 to 3.2 km/s for periods between 5 and 40 s. A strong frequency dependency in attenuation is observed, with attenuation coefficients peaking at shorter periods, consistent with similar trends reported in other tectonically active regions. Comparisons with global tectonic regions reveal higher attenuation beneath the study area, indicating low Q (41–82) values associated with mechanically weak, partially melted crust. The attenuation model suggests intrinsic attenuation as the dominant mechanism, though scattering effects cannot be ignored due to the region's structural complexity. Understanding these attenuation characteristics helps in interpreting seismic data and developing accurate ground motion prediction models, which are crucial for infrastructure resilience and early warning systems in this seismically active region. This, in turn, enhances seismic monitoring capabilities.</div></div>","PeriodicalId":54614,"journal":{"name":"Physics of the Earth and Planetary Interiors","volume":"366 ","pages":"Article 107404"},"PeriodicalIF":2.4,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144290864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Frequency characteristics of electrical conductivity anomalies and the coastal effect","authors":"Igor I. Rokityansky,&nbsp;Artem V. Tereshyn","doi":"10.1016/j.pepi.2025.107400","DOIUrl":"10.1016/j.pepi.2025.107400","url":null,"abstract":"&lt;div&gt;&lt;div&gt;In geophysical studies of the electrical conductivity of the Earth's crust and upper mantle, quantitative integral parameters describing the scale/intensity of electrical conductivity anomalies are almost not used yet. A simple and informative parameter is the total lengthwise conductance G = Q∙ϭ&lt;sub&gt;i&lt;/sub&gt;, where Q is the cross-section area of the anomalous body and ϭ&lt;sub&gt;i&lt;/sub&gt; is its conductivity. In the Earth's lithosphere, anomalous fields are excited/aroused mainly by the conductive mechanism, for which a theory was developed (&lt;span&gt;&lt;span&gt;Rokityansky, 1972&lt;/span&gt;&lt;/span&gt;; &lt;span&gt;&lt;span&gt;Rokityansky, 1975a&lt;/span&gt;&lt;/span&gt;, &lt;span&gt;&lt;span&gt;Rokityansky, 1975b&lt;/span&gt;&lt;/span&gt;; &lt;span&gt;&lt;span&gt;Rokityansky, 1982&lt;/span&gt;&lt;/span&gt;). This theory links G to the frequency characteristic of the anomalous field or more specifically with the period T&lt;sub&gt;0&lt;/sub&gt; at which the real part of the anomalous field reaches a maximum and the imaginary part is equal to 0, changing sign. The anomalous field is mainly represented by the induction arrow. One of the main objectives of this work is to specify the relationship between the observed value T&lt;sub&gt;0&lt;/sub&gt; and the desired G under real Earth conditions, that is, to determine the function G (T&lt;sub&gt;0&lt;/sub&gt;). Estimating G is important for several factors: 1. Any additional parameter enhances a study's possibilities. 2. A highly reliable quantity G determined by magnetic variation profiling allows using it as &lt;em&gt;a priori&lt;/em&gt; information for subsequent computer interpretation of 5-component records. 3. The availability of a quantitative characteristic allows ordering anomalies according to their scale/intensity. The method was first described in 1975 in PEPI, but it was based on simplified Earth models, and the dependence G(T&lt;sub&gt;0&lt;/sub&gt;) was obtained with an error exceeding half an order of magnitude. This paper presents results of new 2D models calculations which were as close as possible to typical Earth structures and the error was reduced by approximately three times. The main models were deep conductors with a compact cross-section and surface conductors represented by rectangular seawater layer of varying depths, forming a coastal effect. In a complicated model of the deep (4000 m) sea with the shelf (100 km wide, 200 m deep), a previously unknown phenomenon was discovered - a very local increase in the anomalous field in the coastal zone of land, which we termed the resonance-synergistic effect. The paper further presents results of 137 observatories of the INTERMAGNET network processing, covering for the first time all latitudes from the Arctic Ocean to Antarctica. At all observatories, induction arrows were calculated for periods of 225, 450, 900, 1800 and 3000 s. Five coastal observatories with induction arrows exceeding 0.8 are shown on maps along with the bathymetry of the adjacent seas. The analysis demonstrated that the regularities calculated on 2D models explain the main patterns of behavior observed ne","PeriodicalId":54614,"journal":{"name":"Physics of the Earth and Planetary Interiors","volume":"366 ","pages":"Article 107400"},"PeriodicalIF":2.4,"publicationDate":"2025-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144297556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Crystallographic preferred orientation of (Mg,Fe)O up to 125 GPa inferred from torsional deformation experiments using a rotational diamond anvil cell","authors":"Bunrin Natsui ,&nbsp;Shintaro Azuma ,&nbsp;Keishi Okazaki ,&nbsp;Kentaro Uesugi ,&nbsp;Masahiro Yasutake ,&nbsp;Saori Kawaguchi-Imada ,&nbsp;Ryuichi Nomura ,&nbsp;Kenji Ohta","doi":"10.1016/j.pepi.2025.107392","DOIUrl":"10.1016/j.pepi.2025.107392","url":null,"abstract":"<div><div>To investigate the texture development of (Mg,Fe)O, we conducted torsional deformation experiments on (Mg,Fe)O with varying Fe contents under pressures up to 125 GPa and temperatures up to 900 K using a rotational diamond anvil cell combined with synchrotron X-rays. The results indicate that the texture development follows the same trend as that observed in MgO, even when the Fe content varies or undergoes a spin transition. However, we found that the crystal plane perpendicular to the compression direction of (Mg,Fe)O could transition from {110} to {100} at lower pressure and temperature conditions than in MgO, attributable to the effect of Fe incorporation. Additionally, the texture of (Mg,Fe)O may vary with the combination of Fe content and strain. In regions with high Fe content and large strains, such as the D″ layer, it may be necessary to evaluate the seismic anisotropy of (Mg,Fe)O based on the texture considering the effects of Fe content and strain.</div></div>","PeriodicalId":54614,"journal":{"name":"Physics of the Earth and Planetary Interiors","volume":"366 ","pages":"Article 107392"},"PeriodicalIF":2.4,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144280680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Porosity and hydrous alteration of the Martian crust from InSight seismic data","authors":"Brigitte Knapmeyer-Endrun ,&nbsp;Ludmila Adam ,&nbsp;Sebastian Carrasco ,&nbsp;Matthew P. Golombek ,&nbsp;Doyeon Kim ,&nbsp;Martin Knapmeyer ,&nbsp;Katarina Miljković ,&nbsp;Ana-Catalina Plesa ,&nbsp;Nicholas H. Warner ,&nbsp;Mark Wieczorek","doi":"10.1016/j.pepi.2025.107383","DOIUrl":"10.1016/j.pepi.2025.107383","url":null,"abstract":"<div><div>The composition and layering of the Martian crust provide important constraints on planetary crustal evolution as well as on present-day conditions, e.g., with regard to the presence of liquid water or ice. The seismic data of the InSight mission yielded new and critical information on crustal structure at several locations on Mars. Here, we use rock physical models to investigate the range of lithologies, porosities and alteration scenarios compatible with seismic P- and S-wave velocities as well as <span><math><msub><mi>v</mi><mi>P</mi></msub></math></span>/<span><math><msub><mi>v</mi><mi>S</mi></msub></math></span> ratios from InSight. We find that present-day crustal porosity extends to 20–25 km depth at all sampled locations, with large Noachian impacts as main drivers for the creation of porosity, and viscous pore closure as likely agent of removal of porosity at depth, resulting in a discontinuous increase in seismic velocities. Spatially heterogeneous seismic velocities can be related to differences in porosity that could be caused by subsequent localized magmatic activity. At the InSight landing site, where seismic data indicate a four-layered crust, hydrated minerals as traces of aqueous alteration are present throughout the crust, though the water within these minerals could be fairly limited at 0.3 wt% or less. The most likely types of hydrated minerals are also consistent with a post-depositional environment that was limited in water. The velocity increase at about 10 km depth beneath InSight can either be attributed to a change in composition from felsic to basaltic, or to a change in porosity by the deposition of Utopia ejecta. A felsic component to the crust, e.g. due to impact-generated buoyant partial melts, can accordingly not be excluded, but would not be present globally. Seismic and geological constraints for the layer at approximately 200 m to 2000 m depth beneath the lander strongly favor basaltic Noachian sediments saturated with a mixture of up to 10 % ice and brine. However, the lateral extent of this present day aquifer is not constrained by the available data.</div></div>","PeriodicalId":54614,"journal":{"name":"Physics of the Earth and Planetary Interiors","volume":"366 ","pages":"Article 107383"},"PeriodicalIF":2.4,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144221602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effect of source-side subduction on PKP differential times and implications for inner core anisotropy","authors":"Stuart Russell ,&nbsp;John Keith Magali ,&nbsp;Kimberly Vallenton ,&nbsp;Christine Thomas","doi":"10.1016/j.pepi.2025.107382","DOIUrl":"10.1016/j.pepi.2025.107382","url":null,"abstract":"<div><div>Directional variation in PKP differential times provides compelling evidence that Earth's inner core is anisotropic. These phases, however, are also sensitive to Earth's heterogeneous mantle. Disentangling the causal structures of PKP differential time anomalies is difficult but nonetheless important if we are to fully understand the structure and evolution of Earth's inner core. A large proportion of earthquakes used to study the inner core originate from subduction zones, which are associated with strongly positive upper mantle seismic velocity anomalies, but the effect of these on the measurements has not yet been investigated.</div><div>In this study, we use AxiSEM3D to simulate the effect of source-side subduction on PKP differential time measurements. We find that some combinations of slab parameters result in artefacts up to several seconds in magnitude, while for others the effect is negligible. We subsequently examine existing data sets of measurements to assess if source-side subduction has a detectable influence on the data, and also to assess if the Scotia slab is the cause of observed anomalous measurements originating from the South Sandwich Islands. We find that the signal of source-side subduction in the data is possibly present but weak, and that the magnitude of anisotropy required by the data is not affected by source-side subduction. Furthermore, the Scotia slab is unlikely to be the cause of the anomalous measurements from the South Sandwich Islands. Nevertheless, we advise caution for future studies as the artefacts caused by source-side subduction may, in some cases, be significant.</div></div>","PeriodicalId":54614,"journal":{"name":"Physics of the Earth and Planetary Interiors","volume":"366 ","pages":"Article 107382"},"PeriodicalIF":2.4,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144212010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Kinetic energy transfer during polarity reversals in a numerical dynamo simulation","authors":"Takumi Kera ,&nbsp;Hiroaki Matsui ,&nbsp;Masaki Matsushima ,&nbsp;Yuto Katoh","doi":"10.1016/j.pepi.2025.107384","DOIUrl":"10.1016/j.pepi.2025.107384","url":null,"abstract":"<div><div>The Earth has a magnetic field with a dominant dipole moment nearly parallel to the axis of Earth's rotation. It is widely accepted that the geomagnetic field is sustained by fluid motion in the Earth's outer core, the so-called dynamo action. Paleomagnetic measurements have shown that the geomagnetic field has reversed its polarity many times. Some geodynamo simulations have been carried out to investigate the physical process of polarity reversals, and the equatorially antisymmetric flow during polarity reversals is found to be stronger than that during stable periods. On the other hand, convective motions in a rotating spherical shell have characteristics that the equatorially symmetric flow is dominant due to the effect of the Earth's rotation. To investigate energy transfers between the equatorially symmetric and antisymmetric flows in the dipole reversals, we have performed geodynamo simulations with polarity reversals. The energy transfer to the equatorially antisymmetric flow is generally small comparing with the buoyancy flux to the equatorially symmetric flow. Toward a polarity reversal, however, it increases in the following manner; (i) the rate of energy transfer from the equatorially symmetric flow to the magnetic field decreases, (ii) the rate of energy transfer from the equatorially symmetric flow to the antisymmetric flow by the advection increases, and (iii) the energy injection by the buoyancy force into the equatorially antisymmetric flow increases. The present results suggest that the intense zonal flow caused by the intense upward flow inside the tangent cylinder in the either hemisphere can trigger a polarity reversal of the magnetic field.</div></div>","PeriodicalId":54614,"journal":{"name":"Physics of the Earth and Planetary Interiors","volume":"365 ","pages":"Article 107384"},"PeriodicalIF":2.4,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144167957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Edges of thermochemical structures in the lower mantle","authors":"Mo Hu,&nbsp;Michael Gurnis","doi":"10.1016/j.pepi.2025.107381","DOIUrl":"10.1016/j.pepi.2025.107381","url":null,"abstract":"<div><div>Global seismic tomography consistently identifies two large low shear velocity provinces (LLSVPs) beneath Africa and the Pacific in the lower mantle. These structures are generally hypothesized to have a thermochemical origin with a higher bulk modulus (<span><math><mi>K</mi></math></span>) than ambient mantle. Regional high-resolution seismic studies have revealed that LLSVPs exhibit diverse edge morphologies, though the factors controlling these variations remain unclear. Here we quantitatively investigate the evolution of LLSVP boundary topographies through high-<span><math><mi>K</mi></math></span> thermochemical convection models. The calculations show that the boundary morphology of a thermochemical pile is primarily controlled by its density and viscosity. Comparison with observed boundary shapes suggests that the African LLSVP may be less dense and thus less stable than the Pacific LLSVP, potentially reflecting differences in their compositions and evolutions. Additionally, the observed boundary complexity indicates that the viscosity of LLSVPs is likely no more than an order of magnitude higher than that of the surrounding mantle.</div></div>","PeriodicalId":54614,"journal":{"name":"Physics of the Earth and Planetary Interiors","volume":"365 ","pages":"Article 107381"},"PeriodicalIF":2.4,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144139492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}