AGU Advances最新文献

{"title":"Megathrust Earthquake Legacy Linked to Changes in Widespread Potential for Methane and Iron Cycling in Glaciated Wetlands","authors":"Jessica Z. Buser-Young,&nbsp;Byron C. Crump,&nbsp;Nicolas Harrichhausen,&nbsp;Frederick S. Colwell","doi":"10.1029/2025AV001821","DOIUrl":"https://doi.org/10.1029/2025AV001821","url":null,"abstract":"<p>Freshwater wetlands are major sources of global methane emissions through biogenic methanogenesis, a process increasingly influenced by climate change. High latitude wetlands are subject to uniquely altered biogeochemical inputs due to disproportionate warming. For example, glacial meltwater delivers metal-rich sediments that are easily reducible. Additionally, if the wetland is located upon a subduction zone, periodic and dynamic geological forces, such as megathrust earthquakes, can disrupt these systems further. To explore these interactions, we analyzed the genomic potential of microbial communities across a glaciated wetland located in an active forearc region subject to repeated megathrust ruptures. We found that sediment microbial communities contained the complete potential for methanogenesis and iron cycling, yet the relative abundance of key methanogenic genes was reduced in recently deposited freshwater sediments despite high levels of organic matter and iron. These findings suggest that megathrust fault activity and associated uplift exerts broad, abrupt change on microbial metabolic potential, and that overlying sediments reflect modern glacial input which modify the development of metabolic potential. Glacial influence likely disrupts methanogenesis by supporting communities capable of dissimilatory iron reduction, which may increase metal-dependent methanotrophy. As climate change accelerates glacial melt, extant and newly developing microbial communities will likely respond rapidly to shifting carbon and mineral inputs, altering carbon cycling dynamics in these sensitive ecosystems. Our work links small scale microbial metabolic potential with some of the largest processes on our planet, revealing how cyclical tectonic events can overprint broad scale biogeochemistry by homogenizing microbial metabolisms and disrupting elemental cycling.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"6 5","pages":""},"PeriodicalIF":8.3,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025AV001821","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145146381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Survey and Modeling of Windblown Ejecta Deposits on Venus","authors":"T. J. Austin,&nbsp;J. G. O’Rourke,&nbsp;N. Izenberg,&nbsp;E. A. Silber","doi":"10.1029/2025AV001906","DOIUrl":"10.1029/2025AV001906","url":null,"abstract":"<p>Venus' thick atmosphere rotates in the same direction as the solid body, but ∼60 times faster. This atmospheric superrotation has produced dozens of windblown ejecta deposits (“parabolas”) on the surface of Venus. The formation and modification of parabolas is an interplay between impacts, aeolian modification, and atmospheric dynamics. We conducted a survey to explore the nature of these sedimentary surface features. First, we observe trends in parabolas' morphology that shed light on how they are deposited and gradated. Changes in the size and radar albedo of parabolas are likely linked to the height and density (respectively) of ejecta plumes at time of formation. Next, we discovered that parabolas show orientations inconsistent with present atmospheric dynamics. This discrepancy may record a change in these dynamics or geologically recent true polar wander at a rate of ∼1° Myr⁻¹, which is similar to that observed on Earth over the past century. These results highlight how overlapping observations at different radar wavelengths provide important insights into the history and character of geologic processes on Venus. Overall, atmospheric superrotation has probably persisted for at least the age of Venus' surface.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"6 5","pages":""},"PeriodicalIF":8.3,"publicationDate":"2025-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025AV001906","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145110635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Monitoring the Pulse of America's Natural Resources From the Orbiting Carbon Observatory Missions","authors":"Mark Svoboda,&nbsp;Oz Kira,&nbsp;Ying Sun,&nbsp;William K. Smith,&nbsp;Troy Magney,&nbsp;Jeffrey D. Wood,&nbsp;Nicholas C. Parazoo","doi":"10.1029/2025AV002063","DOIUrl":"10.1029/2025AV002063","url":null,"abstract":"<p><b>NASA’s FY2026 President’s Budget Request</b> omits continued funding for the Orbiting Carbon Observatory missions (OCO-2 and OCO-3) beyond FY2025, ending September 30, 2025. The unexpected but scientifically transformative observations of solar induced chlorophyll fluorescence (SIF) - originally not part of the missions' design—have opened new opportunities for detecting photosynthesis from space and monitoring the health of the planet's natural resources. Thanks to their high spectral and spatial resolution and over a decade of experience from the project and the science teams, these missions have set a gold standard for space-based retrievals of SIF. Both instruments remain healthy and continue to produce high-quality data that offer great potential to continue transforming our fundamental understanding of terrestrial ecology and to provide actionable information to manage risks associated with extreme weather events such as droughts, floods and wildfires. In this commentary, we outline how OCO-2 and OCO-3 SIF data support crop-yield forecasting, drought early warning, forest and rangeland management, and discuss why keeping these satellites operational is essential for U.S. agriculture, national interests, and global food security.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"6 5","pages":""},"PeriodicalIF":8.3,"publicationDate":"2025-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025AV002063","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145102106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Atmospheric River Impacts on the Greenland Ice Sheet Through the Last Interglacial","authors":"Joseph C. Schnaubelt,&nbsp;Clay R. Tabor,&nbsp;Bette L. Otto-Bliesner,&nbsp;Juan M. Lora","doi":"10.1029/2025AV001653","DOIUrl":"10.1029/2025AV001653","url":null,"abstract":"<p>Earth's mid-latitudes host synoptic scale corridors of intense horizontal moisture transport called atmospheric rivers (ARs). These storms are responsible for substantial heat transport across the mid-latitudes and deliver large amounts of precipitation to impacted locations. ARs occasionally penetrate the Northern Hemisphere high latitudes, resulting in elevated temperatures and anomalous precipitation, which can have a major influence on the Greenland Ice Sheet (GrIS), yet the impact ARs may have had on the GrIS in past climates remains unexplored. The Last Interglacial (LIG; 130,000–115,000 years before present) featured a warmer Arctic than present and a smaller GrIS configuration, providing an ideal time period for characterizing how AR impacts on the GrIS respond to orbital forcing and GrIS topography. Here, we use existing simulations spanning the LIG with a dynamic GrIS to study AR behavior around the GrIS. Results show that there are two mechanisms for AR migration through the LIG. There is a dynamical control across the mid-latitudes through orbitally induced migrations of the prevailing winds and a thermodynamic control at high latitudes due to changes in atmospheric moisture. This results in more warm season ARs at high latitudes early in the LIG which drive substantial melt around the margins of the GrIS and accumulation on the ice sheet interior. Future AR impacts on the GrIS are shown to be similar to the early LIG where an increase in high latitude moisture increases summertime ARs and thus ice sheet ablation around the GrIS margins.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"6 5","pages":""},"PeriodicalIF":8.3,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025AV001653","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145101575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Increased Drought Synchronicity in Indian Rivers Under Anthropogenic Warming","authors":"Dipesh Singh Chuphal,&nbsp;Vimal Mishra","doi":"10.1029/2025AV001850","DOIUrl":"10.1029/2025AV001850","url":null,"abstract":"<p>Synchronous streamflow droughts across multiple river basins can lead to large-scale water scarcity and disruptions in food and water security. However, the drivers and changes in drought synchronicity across Indian rivers remain unexplored due to the limited length of instrumental records. Using streamflow observations and paleohydrological records, we reconstructed streamflow for 45 gauge stations on major Indian rivers, spanning 1200–2012 C.E., to examine the changes and drivers of streamflow drought synchronicity. Our reconstructed streamflow record for the past ∼800 years shows that streamflow drought frequency and synchronicity have increased during the recent period (1850–2012). While past major synchronous droughts in Indian rivers were associated with El Niño and positive Indian Ocean Dipole (IOD) conditions, the recent increase in streamflow drought synchronicity is linked with anthropogenic climate warming. Simulations of the Paleo Model Intercomparison Project Phase 4 (PMIP4-CMIP6) that include both natural and anthropogenic forcings confirm the role of anthropogenic warming in enhancing drought synchronicity. Our findings provide critical insights into the long-term variability of droughts in Indian rivers and underscore the growing risk of large-scale water scarcity.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"6 5","pages":""},"PeriodicalIF":8.3,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025AV001850","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145101548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Connecting Warming Patterns of the Paleo-Ocean to Our Future","authors":"Xiaoqing Liu,&nbsp;Yi Ge Zhang,&nbsp;Matthew Huber,&nbsp;Ping Chang,&nbsp;Lei Wang","doi":"10.1029/2025AV001719","DOIUrl":"10.1029/2025AV001719","url":null,"abstract":"<p>The evolution of the spatial pattern of ocean surface warming affects global radiative feedback, yet different climate models provide varying estimates of future patterns. Paleoclimate data, especially from past warm periods, can help constrain future equilibrium warming patterns. By analyzing marine temperature records spanning the past 10 million years with a regression-based technique that removes temporal dimensions, we extract long-term ocean warming patterns and quantify relative sea surface temperature changes across the global ocean. This analysis revealed a distinct pattern of amplified warming that aligns with equilibrated model simulations under high CO₂ conditions, yet differs from the transient warming pattern observed over the past 160 years. This paleodata-model comparison allows us to identify models that better capture fundamental aspects of Earth's warming response, while suggesting how ocean heat uptake and circulation changes modify the development of warming patterns over time. By combining this paleo-ocean warming pattern with equilibrated model simulations, we characterized the likely evolution of global ocean warming as the climate system approaches equilibrium.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"6 5","pages":""},"PeriodicalIF":8.3,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025AV001719","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145037721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Satellite-Constrained Reanalysis Reveals CO2 Versus Climate Process Compensation Across the Global Land Carbon Sink","authors":"T. Eren Bilir,&nbsp;A. Anthony Bloom,&nbsp;Alexandra G. Konings,&nbsp;Junjie Liu,&nbsp;Nicholas C. Parazoo,&nbsp;Gregory R. Quetin,&nbsp;Alexander J. Norton,&nbsp;Matthew A. Worden,&nbsp;Paul A. Levine,&nbsp;Shuang Ma,&nbsp;Renato K. Braghiere,&nbsp;Marcos Longo,&nbsp;Kevin Bowman,&nbsp;Sassan Saatchi,&nbsp;David S. Schimel,&nbsp;Charles E. Miller,&nbsp;Michael O’Sullivan,&nbsp;Yanghui Kang,&nbsp;Sudhanshu Pandey,&nbsp;Alex J. Patton,&nbsp;Yan Yang,&nbsp;Yanlan Liu","doi":"10.1029/2025AV001689","DOIUrl":"10.1029/2025AV001689","url":null,"abstract":"&lt;p&gt;Terrestrial ecosystems annually absorb &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;∼&lt;/mo&gt;\u0000 &lt;mn&gt;30&lt;/mn&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${sim} 30$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;% of anthropogenic C emissions. The degrees to which contemporary &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mtext&gt;CO&lt;/mtext&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{CO}}_{2}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; and climate trends drive this absorption are uncertain, as are the governing mechanisms. To reduce uncertainty, we use Bayesian model-data integration (CARbon DAta MOdel fraMework) to retrieve a terrestrial biosphere reanalysis where Earth Observations optimally inform mechanistic model processes: observations include satellite- and inventory-based constraints on distributions and change in terrestrial C (including live biomass, dead organic C, and land-atmosphere &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mtext&gt;CO&lt;/mtext&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{CO}}_{2}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; exchanges) and underlying mechanisms (including photosynthesis, deforestation, water storage anomalies, and fire). We find that the impact of 2001–2021's atmospheric &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mtext&gt;CO&lt;/mtext&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{CO}}_{2}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; increase on terrestrial C (+39.4 PgC) opposes and far outweighs the impact of climate trends over this period (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;−&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${-}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;10.5 PgC). Globally, C gains are mostly attributable to live biomass growth (+31.2 PgC), while &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mtext&gt;CO&lt;/mtext&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${text{CO}}_{2}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;-induced dead organic C gains (+7.8 PgC) are compensated by climate-induced losses (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;−&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${-}$&lt;/annotation&gt;\u0000 ","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"6 5","pages":""},"PeriodicalIF":8.3,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025AV001689","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144998631","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shallower Living Depth Instead of Higher Seawater Alkalinity Enhanced Calcification in Bloom-Forming Coccolithophores During Their Pleistocene Acme Event","authors":"Hongrui Zhang,&nbsp;Reto Wijker,&nbsp;Iván Hernández-Almeida,&nbsp;Xiaolin Ma,&nbsp;Xingxing Wang,&nbsp;Thomas Tanner,&nbsp;Heather Stoll","doi":"10.1029/2024AV001609","DOIUrl":"10.1029/2024AV001609","url":null,"abstract":"<p>Coccolithophores are a group of marine phytoplankton precipitating about 50% of total calcite carbonate in the surface ocean. During the Pleistocene, coccolithophores experienced several periodic high-abundance and dominance intervals (acmes) that significantly altered the ocean carbon cycle by increasing the production of carbonate in the ocean. However, the reason for these episodes of enhanced calcification is still unclear. Here, we focus on one of the most significant dominance intervals, the <i>Gephyrocapsa caribbeanica</i> acme event, that lasted between ∼500 and 300 thousand years ago. We find that the variations of seawater alkalinity made only a minor contribution to the increased calcification rates during coccolithophore blooms. Rather, coccolithophore carbon isotopic fractionation indicates that coccolithophores employed a stronger bicarbonate pumping to increase intracellular carbon availability. Greater nutrient availability and shallower living depth likely facilitated higher bicarbonate pumping rates. The upregulation of bicarbonate pumping indicates the vital role of nutrients and light, and not only the ocean carbonate system, in the evolution of marine phytoplankton. Models of future coccolithophore calcification response to changing ocean carbon chemistry would, therefore, benefit from a more comprehensive consideration of how light and nutrient availability affect cellular energy budgets and drive carbon uptake.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"6 5","pages":""},"PeriodicalIF":8.3,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2024AV001609","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144929909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unprecedented Marine Heatwave Significantly Exacerbated the Record-Breaking 2023 East Asian Summer Heatwave","authors":"Satoru Okajima,&nbsp;Yu Kosaka,&nbsp;Takafumi Miyasaka,&nbsp;Rui Ito","doi":"10.1029/2025AV001673","DOIUrl":"10.1029/2025AV001673","url":null,"abstract":"<p>The 2023 East Asian summer experienced a record-breaking compound hot-humid extreme and an unprecedented concurrent marine heatwave (MHW) in surrounding oceans. Understanding and quantifying the impacts of such MHWs on land heatwaves can enhance seasonal prediction skills for these extremes. Here we evaluate the impact of the 2023 MHW on the record-breaking atmospheric heatwave in East Asia during the summer. Through a set of regional atmospheric model experiments, we demonstrate that the MHW significantly exacerbated the 2023 East Asian summer atmospheric heatwave, particularly as a compound hot-humid extreme. The extremely warm ocean amplified both surface air temperature and humidity anomalies, on top of the contributions of background atmospheric circulation anomalies. The MHW influence on air temperature manifests through radiative effects of cloud and water vapor changes. Our results also indicate that the atmospheric heatwave amplifies despite the MHW acts to dampen the western North Pacific subtropical high against large-scale background atmospheric conditions. By examining the effects of both temperature and humidity anomalies through wet-bulb globe temperature, we find that the MHW explains ∼20%–50% of the aggravation and prolonged duration of hot-humid conditions in East Asia, with notable impacts in Japan. Additionally, the recent trend of sea surface warming is shown to substantially amplify the MHW's impact on the heatwave. Our findings underscore the key role of ocean variability and air–sea interactions in surrounding oceans on atmospheric heatwaves that occur in the summer climate in East Asia, highlighting a unique process in the humid and low cloud-abundant maritime East Asia region.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"6 5","pages":""},"PeriodicalIF":8.3,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025AV001673","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144927596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evidence for Stress Diffusion and Along-Strike Segmentation in Cascadia Tremor Migrations Lasting Minutes to Weeks","authors":"Siyuan Zhang,&nbsp;Heidi Houston","doi":"10.1029/2025AV001746","DOIUrl":"10.1029/2025AV001746","url":null,"abstract":"<p>The properties and rheology of subduction zones have been intensively studied to forecast potential megathrust earthquake scenarios. However, in Cascadia, the absence of recent megathrust events limits available seismic evidence. Tectonic tremors occurring downdip of the megathrust provide valuable insights into stress accumulation and propagation and can help constrain stress states and rheology. We build upon a previous method to extract tremor migrations in a large catalog of ∼330,000 tremors, addressing location errors and temporal resolution of the catalog, which are particularly crucial for this region. The spatiotemporally dense tremor activity identified by our improved method, along with the greatly increased number of extracted migrations (∼13,700), facilitates a more quantitative analysis. Our findings suggest that tremor migration is primarily controlled by stress diffusion in a medium exhibiting viscous behavior rather than fluid diffusion. The observed relationship between migration speed and duration implies a diffusivity of 10³–10⁵ m²/s, and aligns with a simple model indicating an approximately 30-km-wide zone of slow slip and tremor propagation. Additionally, we identify three along-strike barriers to tremor migrations, consistent with previously identified segments persisting from shallow to deep. Notably, the barrier near 48.5°N consistently decelerates, terminates, or initiates large tremor episodes, likely due to geometric distortions, including flattening and bending of the slab. In contrast, a barrier near 42.5°N abruptly halts migrations and accumulates stress, but can be breached by sufficient stress perturbation. Thus, tremor migrations can constrain geometric segmentation and diffusive behavior of tremorgenic regions from a dynamic perspective.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"6 5","pages":""},"PeriodicalIF":8.3,"publicationDate":"2025-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025AV001746","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144910006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}