Earth and Planetary Science Letters最新文献

{"title":"Near full locking on the shallow megathrust of the central Cascadia subduction zone revealed by GNSS-Acoustic","authors":"John B. DeSanto ,&nbsp;David A. Schmidt ,&nbsp;Mark Zumberge ,&nbsp;Glenn Sasagawa ,&nbsp;C. David Chadwell","doi":"10.1016/j.epsl.2025.119463","DOIUrl":"10.1016/j.epsl.2025.119463","url":null,"abstract":"<div><div>The Cascadia subduction zone represents a seismic hazard to the Pacific Northwest region of North America, yet the state of fault locking near the deformation front, which could cause a devastating tsunami upon rupturing, remains poorly understood due to limited offshore observations along the subduction zone. In this study, we present the first seafloor geodetic measurements of the horizontal deformation rates on the accretionary prism from an array of four GNSS-Acoustic sites surveyed since 2016. These GNSS-Acoustic sites, despite resting on the North American plate, show velocities that are a significant fraction of the subducting Juan de Fuca plate velocity. In contrast, the continuous GNSS stations along the Oregon coast are moving at velocities &lt;1 cm/yr relative to the North American Plate. Locking models constrained by these offshore velocities show that the subduction zone interface near the deformation front must be nearly locked offshore Oregon. To satisfy both the onshore and offshore geodetic observations, the locked zone must be relatively narrow and only minimal aseismic creep is permissible at the deformation front. These results suggest that appreciable elastic strain has accumulated near the deformation front, which elevates the potential for tsunamigenesis along this portion of the subduction zone.</div></div><div><h3>Plain Text Abstract</h3><div>There is a large earthquake hazard in the region offshore British Columbia, Washington state, Oregon, and Northern California associated with the Cascadia subduction zone, where the Juan de Fuca oceanic plate subducts beneath the North American continental plate. The lack of seafloor observations of plate movement limits our understanding of the hazard, particularly where a future earthquake could rupture up to the seafloor and cause a large tsunami. We present seafloor measurements using Global Navigation Satellite System (GNSS) and acoustic ranging data collected offshore Oregon from 2016–2022 that show that the seafloor is moving at horizontal rates comparable with the subducting Juan de Fuca plate. This suggests that a future earthquake offshore Oregon is capable of rupturing up to the seafloor and causing a devastating tsunami.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"665 ","pages":"Article 119463"},"PeriodicalIF":4.8,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144194530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shear wave splitting reveals east-west variations in Subducted Indian plate morphology beneath Southern Tibetan Plateau","authors":"Shitan Nie ,&nbsp;Xiaobo Tian ,&nbsp;Yun Chen ,&nbsp;Xiaofeng Liang ,&nbsp;Chenglong Wu","doi":"10.1016/j.epsl.2025.119468","DOIUrl":"10.1016/j.epsl.2025.119468","url":null,"abstract":"<div><div>The subduction of the Indian plate beneath the Tibetan Plateau drives key geodynamic processes, yet east-west variations in slab morphology remain poorly resolved. Seismic anisotropy, measured by teleseismic shear wave splitting (SWS), provides critical insights into mantle deformation linked to subduction geometry. Using a new east-west-oriented broadband seismic array (Tibet-30 N) in the southern Lhasa terrane, we analysed 639 SWS measurements and 527 null results. Our study reveals pronounced lateral variations in fast polarization directions (0°–60°) and splitting times (0–0.9 s). Delayed SKS arrivals (∼2 s) and null splitting near the Yadong–Gulu rift (YGR) suggest asthenospheric upwelling through a slab tear, consistent with low upper-mantle velocities. East of the YGR, large splitting times (0.9 s) and NNE fast directions align with flat subduction, while steep subduction west of the YGR induces vertical mantle flow and reduced anisotropy. Step-like changes in splitting parameters across north‒south-trending rifts imply segmented subduction angles: steep between the Tangra Yum Co and Pumqu–Xianza rifts, transitioning to flat eastward. Integrating previous SWS observations, we propose a model where tearing of the Indian slab beneath rifts facilitates asthenospheric upwelling, while lateral mantle flow reflects slab geometry. Our results highlight east-west variations in Indian plate subduction—flat in eastern and western Tibetan plateau and steep centrally—controlled by slab tearing and mantle dynamics.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"665 ","pages":"Article 119468"},"PeriodicalIF":4.8,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144189743","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biological nitrogen cycling within terrestrial hot springs: A Mars analogue system","authors":"Toni Galloway ,&nbsp;Claire R. Cousins ,&nbsp;Eva E. Stüeken ,&nbsp;Jon Telling ,&nbsp;Joanne S. Boden ,&nbsp;Christopher E. Stead ,&nbsp;Carla Greco ,&nbsp;Arola Moreras-Martí ,&nbsp;Mark G. Fox-Powell ,&nbsp;Sophie L. Nixon","doi":"10.1016/j.epsl.2025.119461","DOIUrl":"10.1016/j.epsl.2025.119461","url":null,"abstract":"<div><div>Noachian-age (4.1–3.7Ga) hot spring deposits have been identified on Mars, in addition to fixed nitrogen compounds within Martian surface materials, yet the planet’s nitrogen cycle remains enigmatic and implicates the plausibility of a Martian biosphere. On Earth’s surface, nitrogen is cycled almost exclusively by biological processes which create distinctive isotopic fractionations. We combine geochemical and metagenomic analysis to investigate biological nitrogen cycling within four Mars analogue geothermal systems in Iceland ranging in temperature from 37.8 to 57.1 °C, and propose the geochemical parameters that control biological nitrogen fixation as the primary source of nitrogen into the microbial communities present. We find complete nitrogen fixation and ammonium assimilation gene clusters at all sites, which are also the most abundant nitrogen-cycling genes present. Isotopic fractionations (Δ¹⁵ N) of ∼6 ‰ between locally dissolved N₂ gas and biomass are most parsimoniously explained by organisms relying on Mo-independent nitrogenases for fixation of dinitrogen (N₂). This hypothesis is supported by the presence of genes encoding these enzymes in three out of four sites included in this study, in addition to the more commonly used MoFe nitrogenase. Finally, we find that molybdenum availability is low in the Icelandic hot springs investigated, and potentially therefore in Martian hot springs. This may inhibit conventional Mo-dependent nitrogen fixation in such settings and highlights the influence of wider geological conditions on local biochemistry.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"665 ","pages":"Article 119461"},"PeriodicalIF":4.8,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144167226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Under what circumstances is the final size of a laboratory earthquake predictable at the onset of the P-wave?","authors":"D. Morad ,&nbsp;S. Gvirtzman ,&nbsp;Y. Gil ,&nbsp;J. Fineberg ,&nbsp;E.E. Brodsky","doi":"10.1016/j.epsl.2025.119436","DOIUrl":"10.1016/j.epsl.2025.119436","url":null,"abstract":"<div><div>How do earthquakes begin and what information about this process is contained in a far field seismogram? We present a quantitative analysis of laboratory earthquakes incorporating both laboratory-scale seismic measurements coupled with high-speed imaging of the controlled dynamic ruptures that generated them. We generated variations in the rupture properties by imposing sequences of controlled artificial barriers along the laboratory fault. We first demonstrate that direct measurements of imaged slip events correspond to established seismic analysis of acoustic signals; the seismograms correctly record the rupture moments and maximum moment rates. We then investigate the ruptures’ early growth by comparing their measured seismogram velocities to their final size. Due to higher initial elastic energies imposed prior to nucleation, larger events accelerate more rapidly at the rupture onset. We find that the corresponding seismogram velocities are therefore predictive of the final rupture size. This observation holds in the presence of barriers with one notable exception. Rupture events that overtake a previously arrested rupture are less magnitude predictable, likely because of the stress heterogeneity (and resulting stored elastic energy) induced by the earlier event. For all other events, the higher elastic energy at nucleation results in faster and larger ruptures, and hence the initial seismogram velocity and ultimate size correlate well. This degree of magnitude predictability is consistent with some, but not all recent natural observations. For early warning purposes, we suggest that confining the observational database to the conditions most conducive to magnitude predictability may provide stronger correlations.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"665 ","pages":"Article 119436"},"PeriodicalIF":4.8,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144167227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Oligocene atmospheric CO2 drawdown linked to increased land surface weatherability","authors":"Xue-Ting Wang ,&nbsp;Yibo Yang ,&nbsp;Daniel E. Ibarra ,&nbsp;Xiaobai Ruan ,&nbsp;Zhongyi Yan ,&nbsp;Jimin Sun ,&nbsp;Chun-Sheng Jin","doi":"10.1016/j.epsl.2025.119462","DOIUrl":"10.1016/j.epsl.2025.119462","url":null,"abstract":"<div><div>The Oligocene features a long-term decrease in atmospheric CO₂ levels (<em>p</em>CO₂). However, the driving force of the Oligocene <em>p</em>CO₂ drawdown remains uncertain. Here, we examine the response of silicate chemical weathering to the Oligocene Asian monsoon enhancement in the tectonically active Tibetan Plateau. On tectonic timescales, the silicate weathering rate is elevated in high-weatherability catchments caused by intensive erosion. On orbital timescales, the degree of silicate alteration displays 405-kyr eccentricity cycles, with amplified oscillations corresponding to a vigorous hydrological cycle. Our geologic records, for the first time, reveal that the strength of silicate weathering feedback and CO₂ consumption have increased in a setting of high land surface weatherability. Given the increase in global erosion rate during the Oligocene, the consequent increase in land surface weatherability and weathering feedback strength may modulate the <em>p</em>CO₂ decrease.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"665 ","pages":"Article 119462"},"PeriodicalIF":4.8,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144167294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Miocene marine vertebrate trophic ecology reveals megatooth sharks as opportunistic supercarnivores","authors":"Jeremy McCormack ,&nbsp;Iris Feichtinger ,&nbsp;Benjamin T. Fuller ,&nbsp;Klervia Jaouen ,&nbsp;Michael L. Griffiths ,&nbsp;Nicolas Bourgon ,&nbsp;Harry Maisch IV ,&nbsp;Martin A. Becker ,&nbsp;Jürgen Pollerspöck ,&nbsp;Oliver Hampe ,&nbsp;Gertrud E. Rössner ,&nbsp;Alexandre Assemat ,&nbsp;Wolfgang Müller ,&nbsp;Kenshu Shimada","doi":"10.1016/j.epsl.2025.119392","DOIUrl":"10.1016/j.epsl.2025.119392","url":null,"abstract":"<div><div>Trophic interactions play pivotal roles in marine vertebrate ecology and evolution. Yet, these parameters are especially difficult to determine in fossil communities. To elucidate past trophic palaeoecology, we apply the zinc isotope proxy in a comprehensive analysis of 19 taxa from an early Miocene marine ecosystem, including the megatooth sharks <em>Otodus megalodon</em>/<em>chubutensis</em>. We find substantial resource partitioning among these taxa, with at least three distinct trophic positions and a general increase in body size of taxa towards the top of the food web. The white shark (<em>Carcharodon carcharias</em>) ancestor <em>Carcharodon hastalis</em> had a distinctly different trophic ecology compared to modern <em>C. carcharias</em>, corresponding to the evolutionary gain of tooth serrations between the two species. A comparison among fossil assemblages indicates that megatooth <em>Otodus</em> sharks possessed a higher dietary flexibility on a population level than previously understood, suggesting that they were opportunistic supercarnivores capable of foraging throughout the food web.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"664 ","pages":"Article 119392"},"PeriodicalIF":4.8,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144166678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Remnant Tethyan slab fragments beneath northern Türkiye","authors":"Judith M. Confal ,&nbsp;Tuncay Taymaz ,&nbsp;Tuna Eken ,&nbsp;Maximiliano J. Bezada ,&nbsp;Manuele Faccenda","doi":"10.1016/j.epsl.2025.119458","DOIUrl":"10.1016/j.epsl.2025.119458","url":null,"abstract":"<div><div>For hundreds of millions of years, Gondwana and Laurasia were separated by the Paleo- and Neotethyan oceans. Their eventual collision led to the amalgamation of various continental fragments, initiating multiple subduction cycles in the broader Anatolian region. This study presents, for the first time, five finger-like high velocity perturbation anomalies beneath northern Anatolia (Türkiye), identified through high-resolution P-wave tomography at depths ranging from 80 to 250 km. These anomalies may represent shallow remnants of the Neotethyan slab, which may have remained buoyant due to underplating since the early Cenozoic. Their unique geometry and location suggest active mantle flow, possibly linked to either continental-continental subduction or recent lithospheric foundering.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"664 ","pages":"Article 119458"},"PeriodicalIF":4.8,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Partial convective overturn basins: A qualitative model based on salt minibasins","authors":"Emily Stoll,&nbsp;Nadja Drabon","doi":"10.1016/j.epsl.2025.119420","DOIUrl":"10.1016/j.epsl.2025.119420","url":null,"abstract":"<div><div>Early Earth tectonic processes remain enigmatic. One proposed regime that does not exist on Earth today is partial convective overturn (PCO), where dominantly vertical tectonism is driven by density instabilities. Predicted effects of PCO on the rock record focus on structural, igneous, and metamorphic evidence, many of which are non-unique. To supplement this, we propose a qualitative model of PCO basin sedimentology, stratigraphy, and architecture based on characteristics of salt minibasins. We argue that halotectonics provide an appropriate analogue for PCO surface processes as both have density-driven diapirism resulting in surficial patterns of domal relief and inter-diapir accommodation. Our PCO basin model is characterized by the combination of (1) paleohighs over domes, (2) syn-depositional diapirism, and (3) diapir-influenced basin shape. We propose several lines of evidence for each of these characteristics, including an unroofing provenance sequence, reduced depositional energy away from domes, paleoflow shedding off of the domes, and progressive angular unconformities observed on multiple sides of a dome or basin. We compare our model to previously proposed features of PCO basins and demonstrate that the most optimistic assessment of prior sedimentological studies that suggest PCO formed specific Archean basins often lack evidence of all three characteristics or provide observations from only one side of a dome or basin, leaving ambiguity about whether the basin is truly shaped by diapirism.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"664 ","pages":"Article 119420"},"PeriodicalIF":4.8,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144116741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Global mantle heterogeneity structure from scattered PKPPKP","authors":"Sebastian Rost ,&nbsp;Daniel A. Frost","doi":"10.1016/j.epsl.2025.119415","DOIUrl":"10.1016/j.epsl.2025.119415","url":null,"abstract":"<div><div>To fully understand the dynamics and evolution of our planet we need information from the interior of our planet across a wide range of scale lengths. Seismic methods are limited in their resolution by the sensitivity of the seismic wavelengths. The smallest scalelengths of heterogeneity can be resolved using the scattered seismic wavefield above 1 Hz. Here we aim to image the global small-scale heterogeneity structure from crust to the core-mantle boundary using scattered energy related to <em>P</em><span><math><mspace></mspace><msup><mrow></mrow><mrow><mo>′</mo></mrow></msup></math></span><em>P</em><span><math><mspace></mspace><msup><mrow></mrow><mrow><mo>′</mo></mrow></msup></math></span> (<em>P</em><span><math><mspace></mspace><msup><mrow></mrow><mrow><mo>′</mo></mrow></msup></math></span>•<em>P</em><span><math><mspace></mspace><msup><mrow></mrow><mrow><mo>′</mo></mrow></msup></math></span>) in a novel approach using stacking of high-frequency (0.7 to 2.1 Hz) teleseismic seismograms from single stations. We stack records sensitive to <em>P</em><span><math><mspace></mspace><msup><mrow></mrow><mrow><mo>′</mo></mrow></msup></math></span>•<em>P</em><span><math><mspace></mspace><msup><mrow></mrow><mrow><mo>′</mo></mrow></msup></math></span> energy in 10°x 10° bins across the globe and achieve good coverage of the mantle and crust across more than 60% of the surface area. The dataset especially samples the southern hemisphere and highlights lateral and radial changes in the small-scale (&lt;10 km) heterogeneity structure. Radially, we find the strongest scattering in the lithosphere and upper mantle where most sampled bins show evidence for small-scale heterogeneity in oceanic and continental regions. Similarly, the lowermost mantle in the D″ region shows evidence for widespread small-scale heterogeneity but with distinct lateral changes. Depths around the 660 km discontinuity show evidence for strong heterogeneity with less small-scale structure around mid-oceanic ridges likely related to increased mixing. On the other hand, the mid-mantle (∼1000 km to 2100 km) shows little evidence for scattering, either through a lack of heterogeneity, a lack of impedance contrast between the heterogeneities and the ambient mantle, or heterogeneity scalelengths making them invisible to our scattering probe. Lowermost mantle scattering can pre-dominantly be found near the edges of the Large-Low Velocity Provinces and in regions where subducted slabs reach the core-mantle boundary, potentially indicating a link between scattering heterogeneities and subducted oceanic basalt.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"664 ","pages":"Article 119415"},"PeriodicalIF":4.8,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144105303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unexpected rupture triggering behavior of subshear and free-surface-induced supershear ruptures on stepover","authors":"Zijia Wang ,&nbsp;Zhenguo Zhang","doi":"10.1016/j.epsl.2025.119457","DOIUrl":"10.1016/j.epsl.2025.119457","url":null,"abstract":"<div><div>The ability of a rupture to propagate across a stepover plays a critical role in determining the earthquake’s final magnitude and potential damage. This study systematically investigated the jump distances of 3D strike-slip faults based on the rate- and state-dependent friction law with strong rate weakening. Moreover, we compared the rupture triggering behavior of subshear and free-surface-induced (FSI) supershear ruptures on the secondary fault. Unexpectedly, both simple and barrier models have demonstrated that, compared to FSI supershear rupture, subshear rupture can result in a larger jump distance for the compressional step due to its stronger dynamic stress perturbation. The free surface also plays an important role in this process. Subshear rupture also shows a stronger triggering ability for the extensional step in models that consider the rate-strengthening layer and depth-dependent stresses, as well as models with different overlap distances. These results emphasize the high cascading rupture potential of subshear ruptures and provide important insights for assessing seismic hazards of multi-fault systems.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"664 ","pages":"Article 119457"},"PeriodicalIF":4.8,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144116740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}