Physics of the Earth and Planetary Interiors最新文献

{"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}

{"title":"Effect of thermal conductivity on the simultaneous formation of a stable region at the top of earth's core and magnetic field generation over four billion years","authors":"Takashi Nakagawa ,&nbsp;Shin-ichi Takehiro ,&nbsp;Youhei Sasaki","doi":"10.1016/j.pepi.2025.107380","DOIUrl":"10.1016/j.pepi.2025.107380","url":null,"abstract":"<div><div>The possibility of the emergence of a stratified region in the uppermost part of the Earth's outer core with long-term magnetic field generation is assessed, taking into account uncertainties in the thermal conductivity of the Earth's core and the present-day heat flow across the core-mantle boundary (CMB). The radial structures of the Earth's outer core are calculated for various values of thermal conductivity and CMB heat flow using a one-dimensional thermo-chemical model. The results show that there exist solutions that allow both emergence of stable stratification and long-term magnetic field generation although their thickness of stratified region is thinner than 100 km. In order to satisfy both emergence of stratified region and long-term magnetic field generation, possible value of the present-day CMB heat flow (13–15 TW) suggests a thermal conductivity of 77–121 W/m/K at CMB, which is in good agreement with the values estimated from the electrical conductivity measurements under the Earth's core condition. The thickness of the stratified region in this case is about 50 km, which is also consistent with the thickness of the stratified region estimated from the geomagnetic secular variation. However, the proposed values of thermal conductivity obtained by this analysis could be smaller when the present-day CMB heat flow becomes smaller than the constraint used in this study.</div></div>","PeriodicalId":54614,"journal":{"name":"Physics of the Earth and Planetary Interiors","volume":"365 ","pages":"Article 107380"},"PeriodicalIF":2.4,"publicationDate":"2025-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144105321","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":"Seismic structure of Martian mantle inferred from in situ sound velocity measurements","authors":"P. Chauvigné ,&nbsp;G. Manthilake ,&nbsp;D. Andrault ,&nbsp;J. Chantel ,&nbsp;E. Gardés ,&nbsp;S. Demouchy ,&nbsp;F. Barou ,&nbsp;L. Hennet ,&nbsp;A. Mathieu ,&nbsp;L. Henry ,&nbsp;N. Guignot ,&nbsp;N. Bolfan-Casanova","doi":"10.1016/j.pepi.2025.107378","DOIUrl":"10.1016/j.pepi.2025.107378","url":null,"abstract":"<div><div>We report elastic wave velocity (Vp: P-Waves velocity, and Vs: S-wave velocities) measurements of iron-enriched pyrolite aggregates by a combination of ultrasonic interferometry, synchrotron radiation techniques and multi-anvil apparatus experiments. We carried out eight synchrotrons in situ experiments on two different bulk pyrolite compositions with Fe/(Fe + Mg) ratio (Fe#) of 0.17 and 0.27, over a range of pressures from 3 to 16 GPa and temperatures up to 1000 °C. These data are complemented by seven laboratory ex situ experiments between 5 and 16 GPa and temperatures varying from 900 °C to 1300 °C, using the same starting compositions. Based on these results and previous data on pyrolite composition, we modeled the effect of iron on seismic profiles along several possible Martian areotherms.</div><div>If, as reported in previous works, the Martian mantle had a very high Fe#, for instance Fe# = 0.27, it would be composed of four layers separated by three seismic discontinuities. They would be located at depths of ∼620 km (ΔVp of +8.25 %; ΔVs of +6.72 %), ∼880 km (ΔVp of +2.35 %; ΔVs of 0.03 %) and ∼ 1130 km (ΔVp of −17.88 %; ΔVs of −13.05 %). However, since there is no major discontinuity inferred by InSight's seismic data at depths shallower than 1000 km, we conclude that the Martian mantle presents a Fe# significantly lower than 0.20. For the Fe#0.17 composition, our experiments show a single discontinuity (ΔVp of +5.62 %; ΔVs of +10.44 %) induced by the transition from olivine to wadsleyite at ∼980 km depth, which is compatible with the seismic data.</div></div><div><h3>Plain language summary</h3><div>The geochemical and geophysical data available for Mars suggest an interior enriched in iron, but this information alone is insufficient to constrain the mineralogy and the internal structure of the Martian mantle. In this study, we determine experimentally the elastic wave velocities (Vp: P-Waves velocity, and Vs: S-wave velocities) of two different iron-rich mantle compositions, with Fe# ratios (=Fe/(Mg + Fe)) of 0.17 and 0.27, in a range of pressure and temperature covering the Martian mantle conditions. We then calculate the seismic wave velocity profiles expected in the Mars interior for the different thermal profiles recently proposed in the literature. Three complementary arguments arise in favor of a relatively low Fe# of the Martian mantle: (i) the lack of seismic discontinuity at around 600 km depth suggests the absence of a phase transition to ringwoodite and therefore Fe# significantly lower than ∼0.27. (ii) The report of one seismic discontinuity affecting both Vp and Vs is only compatible with the olivine to wadsleyite transition, which was reported to occur for Fe# lower than 0.2. (iii) A seismic transition reported at 1000 km (i.e. ∼13 GPa) is compatible with our measurements with Fe# of 0.17 (± 0.02).</div></div>","PeriodicalId":54614,"journal":{"name":"Physics of the Earth and Planetary Interiors","volume":"365 ","pages":"Article 107378"},"PeriodicalIF":2.4,"publicationDate":"2025-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144088740","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":"Modelling array beams for the 1979, 1984 and 2021 Granada earthquakes (southern Spain)","authors":"Daniel Stich ,&nbsp;Pınar Büyükakpınar ,&nbsp;Simone Cesca","doi":"10.1016/j.pepi.2025.107379","DOIUrl":"10.1016/j.pepi.2025.107379","url":null,"abstract":"<div><div>Despite the occurrence of large, past earthquakes in the Central Betic Range (Southern Spain), seismicity recorded with digital seismographs is limited to small magnitude events. Here we are interested in the three strongest events (M_W 4.5 to 5.0), of which source models are unclear for different reasons: The June 20th 1979 and June 24th 1984 earthquakes are still characterized by a lack of regional recordings, while the August 12th 2021 earthquake occurred during a teleseismic M8 event. We use beamforming at distant seismic arrays and waveform modelling of depth phases to estimate source parameters for seven earthquakes altogether. The technique is successful at reproducing P-waveforms and at estimating the depth of four recent (1997–2021) earthquakes with M_W &gt; 4. In addition, it is also used along with an inverse scheme that yields source mechanisms similar to regional moment tensor solutions. Inversion suggests normal faulting at depths of 7 km and 9 km for the 1984 and 2021 events, which is consistent with our understanding of regional seismotectonics. Beamforming has been able to extract the 2021 waveforms from the M8 coda wavefield, and could be a suitable approach also for other cases of earthquake coincidence. The most noteworthy result is a strike-slip mechanism at 60 km depth for the 1979 earthquake, which is a singular subcrustal event in this area and might be related to tearing at the edge of the Gibraltar slab.</div></div>","PeriodicalId":54614,"journal":{"name":"Physics of the Earth and Planetary Interiors","volume":"365 ","pages":"Article 107379"},"PeriodicalIF":2.4,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144083714","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":"Attenuation and scattering in the innermost inner core","authors":"Vernon F. Cormier,&nbsp;Ravi Wickramathilake","doi":"10.1016/j.pepi.2025.107368","DOIUrl":"10.1016/j.pepi.2025.107368","url":null,"abstract":"<div><div>Attenuation of PKIKP waves transmitted through the inner core of Earth is modeled to constrain the depth of a transition between an outer and inner inner core having a change in elastic anisotropy. Using reference waveforms inverted from earthquake source-time functions and an average mantle attenuation operator, fits to observed PKIKP waveforms are determined for a two layered model of P wave attenuation in the inner core in which 1/Q_P at 1 Hz has a sharp decrease in a 100 km thick transition zone centered at 650 km radius from Earth's center, coincident with the radius estimated for a change in elastic anisotropy. The attenuation of broadband PKIKP waveforms is found to be dominated by viscoelastic rather than by scattering attenuation. Bounds for parameters describing the spatial spectrum of heterogeneity of the inner inner core, consistent with the scattered coda of both forward scattered PKIKP and back-scattered PKiKP, are estimated to between 4 and 6 km at 2 % and 1 to 2 km at 1 %, for the corner scale length and P velocity fluctuation assuming an exponential autocorrelation. Strong antipodal focusing of scattered waves is observed and predicted from this heterogeneity, particularly within 0.5 great circle degrees of the antipode. Hypotheses for the transition in anelasticity and anisotropy of the - inner inner core include changes in the inner core's composition, superionic state, and/or a change in its heterogeneity texture or crystalline lattice structure.</div></div>","PeriodicalId":54614,"journal":{"name":"Physics of the Earth and Planetary Interiors","volume":"364 ","pages":"Article 107368"},"PeriodicalIF":2.4,"publicationDate":"2025-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143937350","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 impact of LLVPs on regional secular variation of the magnetic field","authors":"Hannah F. Rogers ,&nbsp;Ciarán D. Beggan ,&nbsp;Kathryn A. Whaler","doi":"10.1016/j.pepi.2025.107367","DOIUrl":"10.1016/j.pepi.2025.107367","url":null,"abstract":"<div><div>The Large Low Velocity Provinces (LLVPs) are two poorly understood features at the base of the mantle that are typically studied with seismology and explained using geodynamical models of Earth evolution. However, there are few insights from the geomagnetic perspective about how these mantle features affect main field generation, or if they perturb the motion of the Earth's outer core, without assuming their physical properties. In this study, we test three regional methodologies, namely pointwise estimate on a spatial grid, spherical harmonic analysis, and spherical Slepian functions, to separate secular variation (SV, the first time derivative of the magnetic field) in the areas beneath the LLVPs and their complement.</div><div>While all three methodologies have drawbacks and differences, our findings of the proportion of SV energy inside and outside LLVPs are robust. When inverting data from geomagnetic virtual observatories over the satellite era, the proportion of SV energy under the LLVPs is found to be between 12 % and 18 % of the total SV energy at the Earth's surface which is less than the percentage surface area of the LLVPs. However, the percentage of SV energy is larger than the corresponding surface area when separating the COV-OBS.x2 SV model, between 29 % and 37 % inside LLVPs at the Earth's surface and 33 % and 49 % at the core-mantle boundary (CMB). For both datasets the African LLVP contributes approximately 2.5 times the amount of SV energy as the Pacific LLVP at the Earth's surface but only around 1.3 times more energy at the CMB.</div><div>LLVPs show time-varying SV under their footprint on decadal timescales which, therefore, indicates that core flow varies significantly underneath them rather than being regions of stilted flow. As well as presenting a novel inversion methodology that inverts for a spherical Slepian model, rather than using spherical Slepian functions to separate an existing spherical harmonic model, we also show for the first time that the timings of geomagnetic jerks correspond with inflection points in the magnitude of spectral or spatial energy in regional SV models. We conclude that there is no evidence that SV is systematically suppressed beneath LLVPs.</div></div>","PeriodicalId":54614,"journal":{"name":"Physics of the Earth and Planetary Interiors","volume":"364 ","pages":"Article 107367"},"PeriodicalIF":2.4,"publicationDate":"2025-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144067991","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":"Core-climate coupling: Changes in the Earth’s core dynamics driven by climatic processes","authors":"Mostafa Kiani Shahvandi","doi":"10.1016/j.pepi.2025.107366","DOIUrl":"10.1016/j.pepi.2025.107366","url":null,"abstract":"<div><div>Changes in the Earth's global parameters—particularly variations in the length of day, <span><math><mi>Δ</mi></math></span>LOD—are caused by a multitude of geophysical processes, including that of core dynamics. New signals have emerged in the recent space-geodetic record of <span><math><mi>Δ</mi></math></span>LOD that are not explained solely based upon dynamics of the Earth's core. On the other hand, recent studies emphasize the increasing impact of climatic processes on <span><math><mi>Δ</mi></math></span>LOD, yet even these fail to account for the mentioned emerging signals. Here we propose that these signals are explained once we account for ‘core-climate coupling’ (3C). For this purpose, we develop a new deep learning-based algorithm termed interpretable Bayesian physics-informed quantum deep learning (PIQDLIB) that takes into account all the possible connections between core and climate dynamics. Employing PIQDLIB and using the observations of <span><math><mi>Δ</mi></math></span>LOD, global climate change, and core flow models, we unravel a 3C with a coupling strength of 4<span><math><mo>±</mo></math></span>2 %. This dynamic link elucidates nonlinear interactions between the climate and core processes. To explain the origin of this coupling, we propose a mechanism that accounts for 79<span><math><mo>±</mo></math></span>18 % of the coupling strength and is based upon the pole tide caused by the deviations of the Earth's rotational pole induced by climatic processes, namely, barystatic processes that result in continental-ocean mass redistribution as a result of polar ice sheet and global glaciers melting and shifts in terrestrial water storage. This newly discovered 3C phenomenon is manifested in <span><math><mi>Δ</mi></math></span>LOD as a quasi-decadal oscillation with a main period of 12<span><math><mo>±</mo></math></span>1 year and amplitude of 0.1<span><math><mo>±</mo></math></span>0.02 milliseconds, though it also encompasses small-amplitude interannual and intradecadal periods in the range of <span><math><mo>∼</mo></math></span>6–9 years. These results demonstrate the interplay between internal and external geodynamics, which is fundamental for a better understanding of global geophysics.</div></div>","PeriodicalId":54614,"journal":{"name":"Physics of the Earth and Planetary Interiors","volume":"364 ","pages":"Article 107366"},"PeriodicalIF":2.4,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143917988","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}