Geophysical Research Letters最新文献

{"title":"Comparative Analysis of Seismicity Across Three Depth-Dependent Slip Regimes in the Japan Trench Subduction Zone","authors":"Yuta Ito, Tomoaki Nishikawa, Yoshihiro Ito, Shukei Ohyanagi, Hiroyuki Noda","doi":"10.1029/2025gl120861","DOIUrl":"https://doi.org/10.1029/2025gl120861","url":null,"abstract":"Understanding the cause of spatial variations in seismicity is crucial for comprehending the physics governing earthquake activity. Off Iwate, in the northern Japan Trench subduction zone, the plate boundary can be divided into three distinct zones based on depth-dependent slip regimes: the slow earthquake, asperity, and stable creeping zones. We statistically compare their seismicity characteristics. Our results demonstrate that the slow earthquake zone produces significantly more aftershocks, whereas the asperity zone exhibits the lowest seismic activity. Conversely, the stable creeping zone has the highest rate of background seismicity. We interpret these distinct characteristics based on the respective broad-scale slip behaviors. Moreover, we identify a clear kink in the cumulative magnitude-frequency distribution within the stable creeping zone. Calculations of rupture arrest probability suggest a characteristic rupture size of <i>M</i> 3.7 (∼1 km scale) in this zone. The proposed rupture arrest probability may prove useful for future studies on earthquake source physics.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"19 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147735632","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":"Enhanced Decadal Variance in Nordic Seas With AMOC Weakening in CESM","authors":"Casey R. Patrizio, Henk A. Dijkstra, Anna S. von der Heydt, Robbin Bastiaansen","doi":"10.1029/2025gl118635","DOIUrl":"https://doi.org/10.1029/2025gl118635","url":null,"abstract":"The subpolar North Atlantic (SPNA) exhibits rapid, decadal-scale cooling events in several climate model projections, but the mechanisms behind this variability, particularly the role of a weakening Atlantic Meridional Overturning Circulation (AMOC), remain uncertain. Here we analyze model output from a quasi-equilibrium hosing experiment using the Community Earth System Model version 1 (CESM1) to assess SPNA variability under a gradually declining AMOC. During a 600-year period preceding an AMOC collapse, the overturning strength weakens by ∼15% and decadal surface temperature variance in the Nordic Seas increases eightfold. Statistical analysis links this enhanced variability to feedbacks between ocean convection, salinity, and sea-ice, which strengthen under cooler background conditions associated with reduced AMOC strength. Our results suggest that even modest AMOC weakening is associated with substantially enhanced SPNA variability, pointing to increased regional climate variability under AMOC decline and to potential early warning indicators of AMOC collapse.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"7 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147731926","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":"Simultaneous Compressive Kinetic-Scale Fluctuations and Second-Harmonic Proton Cyclotron Waves Inside a Martian Magnetosheath Structure","authors":"Jintian Yang, Song Fu, Xiaotong Yun, Taifeng Jin, Hui Zhang, Shuyue Pang, Yuequn Lou, Longfei Jia, Yibin Zhao, Yi Qin, Binbin Ni","doi":"10.1029/2025gl119922","DOIUrl":"https://doi.org/10.1029/2025gl119922","url":null,"abstract":"Mars directly interacts with the solar wind and hosts a complex plasma-wave environment. Using MAVEN observations, we identify an event in the dusk-side Martian magnetosheath where strongly compressive sub-cyclotron kinetic-scale fluctuations coexist with second-harmonic proton cyclotron waves (PCWs). The low-frequency fluctuations are quasi-perpendicular and linearly polarized, whereas the harmonic PCWs are quasi-parallel and left-hand polarized. Their large magnetic compressibility indicates that slow-/mirror-like compressive contributions are important. An ion Alfvén ratio analysis shows that the low-frequency fluctuations are inconsistent with both pure kinetic Alfvén wave and pure kinetic slow wave interpretations, favoring mixed kinetic-scale contributions rather than a single pure mode. Ion velocity distributions reveal strong field-aligned beams, suggesting a common free-energy source. During intervals of enhanced low-frequency activity, the fundamental PCW weakens while second harmonics persist, implying mode competition or background modification.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"10 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147731955","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":"Antarctic Meltwater-Stratification Feedback Is Less Pronounced Under High Climate Forcing","authors":"Moritz Kreuzer, Torsten Albrecht, Willem Huiskamp, Stefan Petri, Johannes Feldmann, Georg Feulner, Ricarda Winkelmann","doi":"10.1029/2025gl118643","DOIUrl":"https://doi.org/10.1029/2025gl118643","url":null,"abstract":"Several studies have shown sub-surface warming in the Southern Ocean via an increase in meltwater flux from the Antarctic Ice Sheet (AIS), which can lead to a positive feedback through enhanced basal melting. In this study, we investigate how the feedback strength is related to the prevailing climate in a coupled climate–ice-sheet model. We find that sub-surface temperature increase due to Antarctic meltwater is more pronounced under pre-industrial climate compared to a strong global warming scenario. This is explained by a climate-change induced reduction of vertical overturning in the Southern Ocean, which already leads to strong sub-surface warming without additional meltwater. While in the pre-industrial climate additional meltwater substantially reduces vertical mixing, the additional ice-sheet mass flux into the ocean has less impact when the overturning is already suppressed by climate change. Sub-surface warming due to meltwater flux increase thereby shows a saturation effect under climate warming.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"27 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147731958","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":"Hidden Complexity in Reservoir Flow Regulation Revealed by Spectral Analysis","authors":"Fenghe Zhang, Peirong Lin, Tongbi Tu","doi":"10.1029/2026gl121654","DOIUrl":"https://doi.org/10.1029/2026gl121654","url":null,"abstract":"Understanding reservoir regulation of streamflow is critical for hydrological modeling and ecohydrological assessments, yet our knowledge of how reservoirs preferentially modify flow variability remains limited. Here we apply spectral analysis to daily inflow-outflow data from 205 US reservoirs, decomposing regulation effects into operational mode (how reservoirs modify flow variability) and regulation intensity (magnitude of modification). We identify four distinct operational modes that transcend nominal design purposes, better distinguishing observed regulation behavior than purpose-based classifications. While the dominant mode strongly attenuates high-frequency flow variations, reflecting widespread flood control operations, three additional modes (i.e., seasonal amplification, seasonal smoothing, and high-frequency amplification) are also identified. We also find that larger reservoirs exhibit stronger regulation consistent with their characteristic operational modes. This work reframes our understanding of the complex reservoir regulation behaviors through a novel frequency-domain perspective. The insights hold potential to inform improved hydrological modeling.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"28 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147755192","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":"Spatial Patterns of Shallow Clouds: Challenging the Concept of Defined Regimes","authors":"Giovanni Biagioli, Giulio Mandorli, Lilli Johanna Freischem, Alejandro Casallas, Adrian Mark Tompkins","doi":"10.1029/2025gl119921","DOIUrl":"https://doi.org/10.1029/2025gl119921","url":null,"abstract":"Tropical shallow clouds are a major source of uncertainty in Earth's climate sensitivity, especially through their spatial arrangement, which global climate models do not represent. Efforts to understand their organization have partly relied on classifying observed scenes, identifying four patterns as archetypal regimes. Here we analyze geostationary satellite imagery of the western tropical Atlantic using the &lt;span data-altimg=\"/cms/asset/dfb1d085-856f-48d6-a0f6-804f464f9df6/grl72386-math-0001.png\"&gt;&lt;/span&gt;&lt;mjx-container ctxtmenu_counter=\"117\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" role=\"application\" sre-explorer- style=\"font-size: 103%; position: relative;\" tabindex=\"0\"&gt;&lt;mjx-math aria-hidden=\"true\" location=\"graphic/grl72386-math-0001.png\"&gt;&lt;mjx-semantics&gt;&lt;mjx-mrow&gt;&lt;mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-role=\"latinletter\" data-semantic-speech=\"upper L\" data-semantic-type=\"identifier\"&gt;&lt;mjx-c&gt;&lt;/mjx-c&gt;&lt;/mjx-mi&gt;&lt;/mjx-mrow&gt;&lt;/mjx-semantics&gt;&lt;/mjx-math&gt;&lt;mjx-assistive-mml display=\"inline\" unselectable=\"on\"&gt;&lt;math altimg=\"urn:x-wiley:00948276:media:grl72386:grl72386-math-0001\" display=\"inline\" location=\"graphic/grl72386-math-0001.png\" xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;semantics&gt;&lt;mrow&gt;&lt;mi data-semantic-=\"\" data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic-role=\"latinletter\" data-semantic-speech=\"upper L\" data-semantic-type=\"identifier\"&gt;L&lt;/mi&gt;&lt;/mrow&gt;$L$&lt;/annotation&gt;&lt;/semantics&gt;&lt;/math&gt;&lt;/mjx-assistive-mml&gt;&lt;/mjx-container&gt;-function, a tool based on point pattern theory that quantifies cloud organization across spatial scales. Classical examples of the four patterns show distinct &lt;span data-altimg=\"/cms/asset/56b08997-715f-4a8d-ba72-46e20efaac36/grl72386-math-0002.png\"&gt;&lt;/span&gt;&lt;mjx-container ctxtmenu_counter=\"118\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" role=\"application\" sre-explorer- style=\"font-size: 103%; position: relative;\" tabindex=\"0\"&gt;&lt;mjx-math aria-hidden=\"true\" location=\"graphic/grl72386-math-0002.png\"&gt;&lt;mjx-semantics&gt;&lt;mjx-mrow&gt;&lt;mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-role=\"latinletter\" data-semantic-speech=\"upper L\" data-semantic-type=\"identifier\"&gt;&lt;mjx-c&gt;&lt;/mjx-c&gt;&lt;/mjx-mi&gt;&lt;/mjx-mrow&gt;&lt;/mjx-semantics&gt;&lt;/mjx-math&gt;&lt;mjx-assistive-mml display=\"inline\" unselectable=\"on\"&gt;&lt;math altimg=\"urn:x-wiley:00948276:media:grl72386:grl72386-math-0002\" display=\"inline\" location=\"graphic/grl72386-math-0002.png\" xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;semantics&gt;&lt;mrow&gt;&lt;mi data-semantic-=\"\" data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic-role=\"latinletter\" data-semantic-speech=\"upper L\" data-semantic-type=\"identifier\"&gt;L&lt;/mi&gt;&lt;/mrow&gt;$L$&lt;/annotation&gt;&lt;/semantics&gt;&lt;/math&gt;&lt;/mjx-assistive-mml&gt;&lt;/mjx-container&gt;-function fingerprints, revealing their characteristic clustering and regularity scales and aiding physical interpretation. Yet, when evaluating many scenes at fi","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"25 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147735634","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":"Frequency-Dependent Latitudinal Distributions of Plasmaspheric Plume Hiss Directionality and Amplitude","authors":"Zhiyong Wu, Zhenpeng Su, Huinan Zheng, Yuming Wang","doi":"10.1029/2026gl121667","DOIUrl":"https://doi.org/10.1029/2026gl121667","url":null,"abstract":"Plasmaspheric plume hiss plays a crucial role in shaping Earth's electron radiation belts and influencing magnetosphere–ionosphere energy coupling. However, its generation mechanism remains contested between cyclic-linear and localized-nonlinear models. By analyzing over 64,000 high-resolution plume hiss wave segments from the Van Allen Probes (1 January 2013–31 July 2019), we identify a distinct frequency dependence in their latitudinal distributions of directionality and amplitude. For high-frequency hiss, bidirectional propagation is sharply confined near the magnetic equator, beyond which poleward-propagating waves overwhelmingly dominate, and the wave amplitude increases obviously with latitude. These signatures are consistent with a rapid, single-pass, equatorially confined, nonlinear amplification process. In contrast, low-frequency hiss exhibits a high prevalence and wide latitudinal extension of bidirectional propagation, with relatively smooth amplitude variations. This pattern supports a generation scenario involving slower growth, potentially linear or nonlinear, that is coupled with wave bounce motion along magnetic field lines.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"10 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147735635","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":"A Novel Technique for Extracting the Tidal Magnetic Field: Methodology and Application to a Pre-Processed Dataset of CSES and Swarm","authors":"Haoren Ma, Yanyan Yang, Zhaojin Rong, Dongquan Wang, Jiawei Gao, Zeren Zhima, Jie Wang, Bin Zhou, Werner Magnes, Fei He, Y. Wei","doi":"10.1029/2025gl120594","DOIUrl":"https://doi.org/10.1029/2025gl120594","url":null,"abstract":"The oceanic tidal magnetic field, mainly driven by the circular orbital motion of the Moon, is an essential part of the time-varying geomagnetic field. The previously adopted time-harmonic (TH) base worked well in fitting the primary &lt;span data-altimg=\"/cms/asset/56c91e45-ff9b-45a4-beef-c68eeae66919/grl72472-math-0001.png\"&gt;&lt;/span&gt;&lt;mjx-container ctxtmenu_counter=\"204\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" role=\"application\" sre-explorer- style=\"font-size: 103%; position: relative;\" tabindex=\"0\"&gt;&lt;mjx-math aria-hidden=\"true\" location=\"graphic/grl72472-math-0001.png\"&gt;&lt;mjx-semantics&gt;&lt;mjx-mrow&gt;&lt;mjx-msub data-semantic-children=\"0,1\" data-semantic- data-semantic-role=\"latinletter\" data-semantic-speech=\"upper M 2\" data-semantic-type=\"subscript\"&gt;&lt;mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-parent=\"2\" data-semantic-role=\"latinletter\" data-semantic-type=\"identifier\"&gt;&lt;mjx-c&gt;&lt;/mjx-c&gt;&lt;/mjx-mi&gt;&lt;mjx-script style=\"vertical-align: -0.15em; margin-left: -0.081em;\"&gt;&lt;mjx-mn data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"2\" data-semantic-role=\"integer\" data-semantic-type=\"number\" size=\"s\"&gt;&lt;mjx-c&gt;&lt;/mjx-c&gt;&lt;/mjx-mn&gt;&lt;/mjx-script&gt;&lt;/mjx-msub&gt;&lt;/mjx-mrow&gt;&lt;/mjx-semantics&gt;&lt;/mjx-math&gt;&lt;mjx-assistive-mml display=\"inline\" unselectable=\"on\"&gt;&lt;math altimg=\"urn:x-wiley:00948276:media:grl72472:grl72472-math-0001\" display=\"inline\" location=\"graphic/grl72472-math-0001.png\" xmlns=\"http://www.w3.org/1998/Math/MathML\"&gt;&lt;semantics&gt;&lt;mrow&gt;&lt;msub data-semantic-=\"\" data-semantic-children=\"0,1\" data-semantic-role=\"latinletter\" data-semantic-speech=\"upper M 2\" data-semantic-type=\"subscript\"&gt;&lt;mi data-semantic-=\"\" data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic-parent=\"2\" data-semantic-role=\"latinletter\" data-semantic-type=\"identifier\"&gt;M&lt;/mi&gt;&lt;mn data-semantic-=\"\" data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic-parent=\"2\" data-semantic-role=\"integer\" data-semantic-type=\"number\"&gt;2&lt;/mn&gt;&lt;/msub&gt;&lt;/mrow&gt;${M}_{2}$&lt;/annotation&gt;&lt;/semantics&gt;&lt;/math&gt;&lt;/mjx-assistive-mml&gt;&lt;/mjx-container&gt; tidal field, but extracting the other weaker modes like the &lt;span data-altimg=\"/cms/asset/f1bb9c00-1d85-4750-a5ec-5f5e0c7a30cb/grl72472-math-0002.png\"&gt;&lt;/span&gt;&lt;mjx-container ctxtmenu_counter=\"205\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" role=\"application\" sre-explorer- style=\"font-size: 103%; position: relative;\" tabindex=\"0\"&gt;&lt;mjx-math aria-hidden=\"true\" location=\"graphic/grl72472-math-0002.png\"&gt;&lt;mjx-semantics&gt;&lt;mjx-mrow&gt;&lt;mjx-msub data-semantic-children=\"0,1\" data-semantic- data-semantic-role=\"latinletter\" data-semantic-speech=\"upper N 2\" data-semantic-type=\"subscript\"&gt;&lt;mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"italic\" data-semantic- data-semantic-parent=\"2\" data-semantic-role=\"latinletter\" data-semantic-type=\"identifier\"&gt;&lt;mjx-c&gt;&lt;/mjx-c&gt;&lt;/mjx-mi&gt;&lt;mjx-script style=\"vertical-align: -0.15em; margin-left: -0.085e","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"58 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147735631","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":"Variability of the Deep-Water Inputs From the Adriatic and Aegean Seas Over the Period of Sapropel S1 Deposition Based on Foraminiferal Nd Isotopes","authors":"Guohui Gao, Christophe Colin, Giuseppe Siani, Jiawang Wu, Sophie Sepulcre, Rosella Pinna-Jamme, Arnaud Dapoigny, Amalia Filippidi, Gert J. de Lange","doi":"10.1029/2025gl118971","DOIUrl":"https://doi.org/10.1029/2025gl118971","url":null,"abstract":"Deep-water of the eastern Mediterranean basins mainly forms in the Adriatic Sea and episodically in the Aegean Sea. However, past and future variability under changing temperature and freshwater inputs remains unclear. We reconstruct seawater ε_Nd from Northern Ionian Sea cores to trace intermediate- and deep-water provenance during the Holocene. High organic matter deposition during S1a and S1b corresponds to radiogenic ε_Nd values (up to −4.9), indicating reduced and shallower Adriatic Deep Water (AdDW) formation, with Ionian Sea increasingly dominated by Aegean deep water (AeDW). The re-ventilation of deep-water at ∼8.2 ka is marked by unradiogenic ε_Nd (−6.5), implying active AdDW formation. In contrast, a second re-ventilation within the S1b at intermediate depth is associated with radiogenic ε_Nd values (−4.5) attributed to the formation of the radiogenic intermediate water from the eastern basin (LIW). These results demonstrate the high sensitivity of Mediterranean deep-water formation to freshwater forcing and abrupt climate change.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"143 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147731954","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":"Slab Dehydration Observed Down to Lower Seismicity Plane Depths in the Northern Chile Subduction Zone","authors":"Nazia Hassan, Christian Sippl","doi":"10.1029/2025gl120940","DOIUrl":"https://doi.org/10.1029/2025gl120940","url":null,"abstract":"We present a high-resolution local earthquake tomography model that constrains the distribution of hydration and dehydration processes within the subducting Nazca slab beneath Northern Chile. We image a distinct downdip transition from high <i>V</i>_p/<i>V</i>_s (∼1.75) over low <i>V</i>_p/<i>V</i>_s (∼1.65) to a homogeneously high <i>V</i>_p/<i>V</i>_s slab at depths of <span data-altimg=\"/cms/asset/0e51ffd0-8c31-4866-8d0b-086e827c6856/grl72446-math-0001.png\"></span><mjx-container ctxtmenu_counter=\"38\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" role=\"application\" sre-explorer- style=\"font-size: 103%; position: relative;\" tabindex=\"0\"><mjx-math aria-hidden=\"true\" location=\"graphic/grl72446-math-0001.png\"><mjx-semantics><mjx-mrow><mjx-mo data-semantic- data-semantic-role=\"inequality\" data-semantic-speech=\"greater than or equals\" data-semantic-type=\"relation\"><mjx-c></mjx-c></mjx-mo></mjx-mrow></mjx-semantics></mjx-math><mjx-assistive-mml display=\"inline\" unselectable=\"on\"><math altimg=\"urn:x-wiley:00948276:media:grl72446:grl72446-math-0001\" display=\"inline\" location=\"graphic/grl72446-math-0001.png\" xmlns=\"http://www.w3.org/1998/Math/MathML\"><semantics><mrow><mo data-semantic-=\"\" data-semantic-role=\"inequality\" data-semantic-speech=\"greater than or equals\" data-semantic-type=\"relation\">≥</mo></mrow>${ge} $</annotation></semantics></math></mjx-assistive-mml></mjx-container>85 km. This transition corresponds to the transition between a double seismic zone and a broad, highly seismogenic volume. The latter is overlain by the highest <i>V</i>_p/<i>V</i>_s values (1.8–1.87) in the model volume, confined to the portion of the mantle wedge just above the slab top. Taken together, these observations imply the presence of slab hydration and the occurrence of dehydration reactions down to depths of ∼30 km below the slab top. While these processes are visible via their <i>V</i>_p/<i>V</i>_s signature where seismicity rates are high, we speculate that lower dehydration rates further updip are insufficient to create a similar fluid signature.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"21 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2026-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147755219","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}