AGU Advances最新文献

{"title":"Volcanic Arc Weathering Rates in the Humid Tropics Controlled by the Interplay Between Physical Erosion and Precipitation","authors":"Angus K. Moore,&nbsp;Kimberly Méndez Méndez,&nbsp;K. Stephen Hughes,&nbsp;Darryl E. Granger","doi":"10.1029/2023AV001066","DOIUrl":"https://doi.org/10.1029/2023AV001066","url":null,"abstract":"<p>Volcanic arcs are chemical weathering hotspots that may contribute disproportionately to global CO₂ consumption through silicate weathering. Accurately modeling the impact of volcanic-arc landscapes on the Earth's long-term carbon cycle requires understanding how climate and physical erosion control weathering fluxes from arc landscapes. We evaluate these controls by examining the covariation of stream solutes, sediment geochemistry, and long-term physical erosion fluxes inferred from cosmogenic ³⁶Cl in magnetite in volcanic watersheds in Puerto Rico that span a ca. 15-fold gradient in specific discharge. Analysis of this data using power-law relationships demonstrates that CO₂ consumption from arc-rock weathering in the humid tropics is more strongly limited by physical erosion and the supply of primary minerals to the weathering zone than by temperature or the flux of fresh, chemically reactive waters through the critical zone. However, a positive correlation between long-term physical erosion fluxes and specific discharge is also observed. This indicates that fresh mineral supply in arc environments may ultimately depend on precipitation rates, which may maintain a coupling between arc-rock weathering fluxes and climate under principally supply limited weathering conditions.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"5 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023AV001066","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140053093","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":"Global-Scale Convergence Obscures Inconsistencies in Soil Carbon Change Predicted by Earth System Models","authors":"Zheng Shi,&nbsp;Forrest M. Hoffman,&nbsp;Min Xu,&nbsp;Umakant Mishra,&nbsp;Steven D. Allison,&nbsp;Jizhong Zhou,&nbsp;James T. Randerson","doi":"10.1029/2023AV001068","DOIUrl":"https://doi.org/10.1029/2023AV001068","url":null,"abstract":"<p>Soil carbon (C) responses to environmental change represent a major source of uncertainty in the global C cycle. Feedbacks between soil C stocks and climate drivers could impact atmospheric CO₂ levels, further altering the climate. Here, we assessed the reliability of Earth system model (ESM) predictions of soil C change using the Coupled Model Intercomparison Project phases 5 and 6 (CMIP5 and CMIP6). ESMs predicted global soil C gains under the high emission scenario, with soils taking up 43.9 Pg (95% CI: 9.2–78.5 Pg) C on average during the 21st century. The variation in global soil C change declined significantly from CMIP5 (with average of 48.4 Pg [95% CI: 2.0–94.9 Pg] C) to CMIP6 models (with average of 39.3 Pg [95% CI: 23.9–54.7 Pg] C). For some models, a small C increase in all biomes contributed to this convergence. For other models, offsetting responses between cold and warm biomes contributed to convergence. Although soil C predictions appeared to converge in CMIP6, the dominant processes driving soil C change at global or biome scales differed among models and in many cases between earlier and later versions of the same model. Random Forest models, for soil carbon dynamics, accounted for more than 63% variation of the global soil C change predicted by CMIP5 ESMs, but only 36% for CMIP6 models. Although most CMIP6 models apparently agree on increased soil C storage during the 21st century, this consensus obscures substantial model disagreement on the mechanisms underlying soil C response, calling into question the reliability of model predictions.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"5 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023AV001068","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140015114","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":"Seismic Waves Used to Measure How Ice Shelf Rifting Velocity Is Limited by Ocean Coupling","authors":"T. Hudson","doi":"10.1029/2024AV001189","DOIUrl":"https://doi.org/10.1029/2024AV001189","url":null,"abstract":"&lt;p&gt;Ice shelves play an important role in controlling how fast ice moves off the Antarctic continent into the oceans, promoting sea-level rise. These floating bodies of ice effectively buttress the grounded ice behind them, hindering the flow of ice off land while also somewhat reducing the exposure of the grounding line to ocean melting (Gudmundsson, &lt;span&gt;2013&lt;/span&gt;). Their importance can perhaps be exemplified by comparing Antarctic ice streams terminating at ice shelves to Greenland's directly exposed calving fronts (Benn et al., &lt;span&gt;2017&lt;/span&gt;), where ice is currently being lost at a far greater rate (Oppenheimer et al., &lt;span&gt;2019&lt;/span&gt;). However, Antarctic ice shelves are vulnerable to rifting (Larour et al., &lt;span&gt;2021&lt;/span&gt;) and catastrophic breakup (Glasser &amp; Scambos, &lt;span&gt;2008&lt;/span&gt;). Olinger et al. (&lt;span&gt;2024&lt;/span&gt;) use seismology to shed new light on how such rifting can be limited by ocean coupling.&lt;/p&gt;&lt;p&gt;Olinger et al. (&lt;span&gt;2024&lt;/span&gt;) use observations combined with numerical modeling to highlight how vulnerable ice shelves can be to rifting, and in particular how the ocean can play a role in setting rifting velocity (see Figure 1). This work is particularly exciting for two reasons. First, they combine satellite and seismic observations with a numerical model, to not only understand but also quantify the rifting process. Second, they find that coupling of the ice shelf rift with the ocean actually limits the rate of rift propagation. This is contrary to the majority of ice shelf-ocean interactions, which generally act to exacerbate ice shelf instability (e.g., Holland et al. (&lt;span&gt;2008&lt;/span&gt;)).&lt;/p&gt;&lt;p&gt;Satellite observations are one of the most effective means of observing ice shelf rifting. Olinger et al. (&lt;span&gt;2024&lt;/span&gt;) use Synthetic Aperture Radar (SAR) imagery to map changes in the rift extent at Pine Island Glacier (PIG) ice shelf, before and after a major rifting event. However, one of the greatest challenges posed by such remote sensing data is the poor temporal sampling (Baumhoer et al., &lt;span&gt;2018&lt;/span&gt;). This is evident in the data used by Olinger et al. (&lt;span&gt;2024&lt;/span&gt;), where they analyze images six days apart, only capturing the rift extent prior to and post the major rifting episode. During this time, they find that the rift lengthens by 10.5 km. Capturing higher resolution temporal behavior of the rift is critical for understanding rifting in more detail. Olinger et al. (&lt;span&gt;2024&lt;/span&gt;) use seismic observations from instruments deployed on the ice shelf to provide continuous temporal sampling of the rift. They searched through the continuous data to identify the dominant rifting event, which they assume accommodated the majority of rifting observed in the satellite data. From this rifting event, they observe an increase in seismic energy from surface waves of 300 s duration, which allows them to quantify a rifting velocity of 35 m s&lt;sup&gt;−1&lt;/sup&gt;. Although this velocity may appear fast from","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"5 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024AV001189","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139987434","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":"A Post-Launch Summary of the Science of NASA's Psyche Mission","authors":"Steven. D. Dibb,&nbsp;Erik Asphaug,&nbsp;James F. Bell,&nbsp;Richard P. Binzel,&nbsp;William F. Bottke,&nbsp;Saverio Cambioni,&nbsp;John M. Christoph,&nbsp;Linda T. Elkins-Tanton,&nbsp;Ralf Jaumann,&nbsp;David J. Lawrence,&nbsp;Rona Oran,&nbsp;Joseph G. O’Rourke,&nbsp;Carol Polansky,&nbsp;Benjamin P. Weiss,&nbsp;Mark Wieczorek,&nbsp;David. A. Williams","doi":"10.1029/2023AV001077","DOIUrl":"https://doi.org/10.1029/2023AV001077","url":null,"abstract":"<p>Astronomical observations indicate that asteroid (16) Psyche is a large, high-density (likely &gt;3,400 kg·m⁻³), metal-rich (30–55 vol. %) asteroid. Psyche may be remnant core material or it could be a primordial, undifferentiated metal-rich object. We discuss the science objectives of the upcoming Psyche mission, which will employ three instruments (the Magnetometer, Multispectral Imager, and Gamma-Ray and Neutron Spectrometer) and will use Doppler tracking of the spacecraft to explore the asteroid. This mission will shed light on the nature and origins of metal-rich objects in the solar system and beyond, including the cores of the terrestrial planets.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"5 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023AV001077","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139976361","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":"A Perspective on the Future of CMIP","authors":"Bjorn Stevens","doi":"10.1029/2023AV001086","DOIUrl":"https://doi.org/10.1029/2023AV001086","url":null,"abstract":"<p>The Coupled Model Intercomparison Project (CMIP) has demonstrated the importance of climate modeling for climate research and its usefulness for climate services. The latter has increased CMIP's operational burden, so much so that serving IPCC has become its animating force. Attempting to satisfy an operational mandate through a coordinated research project diminishes both the service and the research. Regaining the initiative will require CMIP to transition the quasi-operational system it has developed to an operational setting. Doing so would allow CMIP to focus on developing an international scientific agenda to encourage and exploit advances in climate modeling.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023AV001086","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139915693","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":"Ocean Coupling Limits Rupture Velocity of Fastest Observed Ice Shelf Rift Propagation Event","authors":"Stephanie D. Olinger,&nbsp;Bradley P. Lipovsky,&nbsp;Marine A. Denolle","doi":"10.1029/2023AV001023","DOIUrl":"https://doi.org/10.1029/2023AV001023","url":null,"abstract":"<p>The Antarctic ice sheet is buttressed by floating ice shelves that calve icebergs along large fractures called rifts. Despite the significant influence exerted by rifting on ice shelf geometry and buttressing, the scarcity of in situ observations of rift propagation contributes considerable uncertainty to understanding rift dynamics. Here, we report the first-ever seismic recording of a multiple-kilometer rift propagation event. Remote sensing and seismic recordings reveal that a rift in the Pine Island Glacier Ice Shelf extended 10.53 km at a speed of 35.1 m/s, the fastest known ice fracture at this scale. We simulate ocean-coupled rift propagation and find that the dynamics of water flow within the rift limit the propagation rate, resulting in rupture two orders of magnitude slower than typically predicted for brittle fracture. Using seismic recordings of the elastic waves generated during rift propagation, we estimate that ocean water flows into the rift at a rate of at least 2,300 m³/s during rift propagation and causes mixing in the subshelf cavity. Our observations support the hypotheses that large ice shelf rift propagation events are brittle, hydrodynamically limited, and exhibit sensitive coupling with the surrounding ocean.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023AV001023","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139695309","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":"The Problem of Tree Senescence in the Role of Elevated CO2 and the Carbon Cycle","authors":"Sean M. McMahon","doi":"10.1029/2023AV001103","DOIUrl":"https://doi.org/10.1029/2023AV001103","url":null,"abstract":"&lt;p&gt;Climate change affects the terrestrial carbon cycle through many pathways. In particular, CO&lt;sub&gt;2&lt;/sub&gt; fertilization can shape tree growth, death, and tolerance or resilience to climate change (Walker et al., &lt;span&gt;2021&lt;/span&gt;). Titrating the role of the different influences of elevated atmospheric CO&lt;sub&gt;2&lt;/sub&gt; (eCO&lt;sub&gt;2&lt;/sub&gt;) on the carbon cycle through forest ecology has encouraged large experiments (Free-Air CO&lt;sub&gt;2&lt;/sub&gt; Enrichment [FACE] experiments), analyses of dendrochronological and inventory data sets (Brienen et al., &lt;span&gt;2020&lt;/span&gt;), and vegetation model simulations to identify and quantify potential effects at different scales (Needham et al., &lt;span&gt;2020&lt;/span&gt;). In this issue, Marquès et al. (&lt;span&gt;2023&lt;/span&gt;) tackle a potentially critical yet empirically challenging indirect consequence of eCO&lt;sub&gt;2&lt;/sub&gt; fertilization: although faster growth in response to eCO&lt;sub&gt;2&lt;/sub&gt; might accelerate carbon fixation, this acceleration could be offset by an increase in large tree mortality. Termed the Grow Fast-Die Young hypothesis (GFDY), this reflects a role of tree size thresholds associated with increased mortality, or “size-driven senescence” in shaping the population-wide consequences of accelerated tree growth.&lt;/p&gt;&lt;p&gt;GFDY requires that size, and not age, is the primary determinant of the mortality of mature trees. Were senescence (late-life increase in mortality) due solely to age, growing fast would be decoupled from dying young, and any increase in life-time productivity would lead to a direct increase in forest biomass. This would offset atmospheric CO&lt;sub&gt;2&lt;/sub&gt; concentration increases as the fertilization effect of eCO&lt;sub&gt;2&lt;/sub&gt; would lead to a larger terrestrial carbon sink. Although certainly age plays a role in tree mortality (e.g., the advance of pathogens, damage accrued over life) the types of processes that lead to animal death due to age (telomere shortening, mutation accumulation, etc.) appear not to be prevalent in the meristems or distal tissues and organs of even very old trees (Klimešová et al., &lt;span&gt;2015&lt;/span&gt;; Mencuccini et al., &lt;span&gt;2005&lt;/span&gt;; Thomas, &lt;span&gt;2013&lt;/span&gt;); but see (Cannon et al., &lt;span&gt;2022&lt;/span&gt;). Size-based tree senescence supports the premise that the GFDY would subtract from any potential sink gained from eCO&lt;sub&gt;2&lt;/sub&gt; growth stimulation. This raises critical questions: how quickly and how universally might the GFDY operate?&lt;/p&gt;&lt;p&gt;Any potential GFDY responses will be entangled with other trends in climate change, and complex physiological and ecological tradeoffs from the scale of the cell to the community. This complicates distinguishing the signal from noise. Marquès et al. (&lt;span&gt;2023&lt;/span&gt;), recognizing that multiple mechanisms contribute to stand-level growth, conceived an elegant way of testing hypotheses about the eCO&lt;sub&gt;2&lt;/sub&gt; effect, acknowledging contingencies of stand dynamics, and identifying key sensitivities that determine stand responses to eCO&lt;sub&gt;2&lt;/sub&gt;","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023AV001103","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139676568","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":"Balancing Non-CO2 GHG Emissions and Soil Carbon Change in U.S. Rice Paddies: A Retrospective Meta-Analysis and Agricultural Modeling Study","authors":"Jingting Zhang,&nbsp;Hanqin Tian,&nbsp;Yongfa You,&nbsp;Xin-Zhong Liang,&nbsp;Zutao Ouyang,&nbsp;Naiqing Pan,&nbsp;Shufen Pan","doi":"10.1029/2023AV001052","DOIUrl":"https://doi.org/10.1029/2023AV001052","url":null,"abstract":"<p>U.S. rice paddies, critical for food security, are increasingly contributing to non-CO₂ greenhouse gas (GHG) emissions like methane (CH₄) and nitrous oxide (N₂O). Yet, the full assessment of GHG balance, considering trade-offs between soil organic carbon (SOC) change and non-CO₂ GHG emissions, is lacking. Integrating an improved agroecosystem model with a meta-analysis of multiple field studies, we found that U.S. rice paddies were the rapidly growing net GHG emission sources, increased 138% from 3.7 ± 1.2 Tg CO₂eq yr⁻¹ in the 1960s to 8.9 ± 2.7 Tg CO₂eq yr⁻¹ in the 2010s. CH₄, as the primary contributor, accounted for 10.1 ± 2.3 Tg CO₂eq yr⁻¹ in the 2010s, alongside a notable rise in N₂O emissions by 0.21 ± 0.03 Tg CO₂eq yr⁻¹. SOC change could offset 14.0% (1.45 ± 0.46 Tg CO₂eq yr⁻¹) of the climate-warming effects of soil non-CO₂ GHG emissions in the 2010s. This escalation in net GHG emissions is linked to intensified land use, increased atmospheric CO₂, higher synthetic nitrogen fertilizer and manure application, and climate change. However, no/reduced tillage and non-continuous irrigation could reduce net soil GHG emissions by approximately 10% and non-CO₂ GHG emissions by about 39%, respectively. Despite the rise in net GHG emissions, the cost of achieving higher rice yields has decreased over time, with an average of 0.84 ± 0.18 kg CO₂eq ha⁻¹ emitted per kilogram of rice produced in the 2010s. The study suggests the potential for significant GHG emission reductions to achieve climate-friendly rice production in the U.S. through optimizing the ratio of synthetic N to manure fertilizer, reducing tillage, and implementing intermittent irrigation.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023AV001052","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139676486","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":"“Seeing” Beneath the Clouds—Machine-Learning-Based Reconstruction of North African Dust Plumes","authors":"Franz Kanngießer,&nbsp;Stephanie Fiedler","doi":"10.1029/2023AV001042","DOIUrl":"https://doi.org/10.1029/2023AV001042","url":null,"abstract":"<p>Mineral dust is one of the most abundant atmospheric aerosol species and has various far-reaching effects on the climate system and adverse impacts on air quality. Satellite observations can provide spatio-temporal information on dust emission and transport pathways. However, satellite observations of dust plumes are frequently obscured by clouds. We use a method based on established, machine-learning-based image in-painting techniques to restore the spatial extent of dust plumes for the first time. We train an artificial neural net (ANN) on modern reanalysis data paired with satellite-derived cloud masks. The trained ANN is applied to cloud-masked, gray-scaled images, which were derived from false color images indicating elevated dust plumes in bright magenta. The images were obtained from the Spinning Enhanced Visible and Infrared Imager instrument onboard the Meteosat Second Generation satellite. We find up to 15% of summertime observations in West Africa and 10% of summertime observations in Nubia by satellite images miss dust plumes due to cloud cover. We use the new dust-plume data to demonstrate a novel approach for validating spatial patterns of the operational forecasts provided by the World Meteorological Organization Dust Regional Center in Barcelona. The comparison elucidates often similar dust plume patterns in the forecasts and the satellite-based reconstruction, but once trained, the reconstruction is computationally inexpensive. Our proposed reconstruction provides a new opportunity for validating dust aerosol transport in numerical weather models and Earth system models. It can be adapted to other aerosol species and trace gases.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023AV001042","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139655149","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":"Laboratory Hydrofractures as Analogs to Tectonic Tremors","authors":"C. Yuan,&nbsp;T. Cochard,&nbsp;M. Denolle,&nbsp;J. Gomberg,&nbsp;A. Wech,&nbsp;L. Xiao,&nbsp;D. Weitz","doi":"10.1029/2023AV001002","DOIUrl":"https://doi.org/10.1029/2023AV001002","url":null,"abstract":"<p>The fracture of Earth materials occurs over a wide range of time and length scales. Physical conditions, particularly the stress field and Earth material properties, may condition rupture in a specific fracture regime. In nature, fast and slow fractures occur concurrently: tectonic tremor events are fast enough to emit seismic waves and frequently accompany slow earthquakes, which are too slow to emit seismic waves and are referred to as aseismic slip events. In this study, we generate simultaneous seismic and aseismic processes in a laboratory setting by driving a penny-shaped crack in a transparent sample with pressurized fluid. We leverage synchronized high-speed imaging and high-frequency acoustic emission (AE) sensing to visualize and listen to the various sequences of propagation (breaks) and arrest (sticks) of a fracture undergoing stick-break instabilities. Slow radial crack propagation is facilitated by fast tangential fractures. Fluid viscosity and pressure regulate the fracture dynamics of slow and fast events, and control the inter-event time and the energy released during individual fast events. These AE signals share behaviors with observations of episodic tremors in Cascadia, United States; these include: (a) bursty or intermittent slow propagation, and (b) nearly linear scaling of radiated energy with area. Our laboratory experiments provide a plausible model of tectonic tremor as an indicative of hydraulic fracturing facilitating shear slip during slow earthquakes.</p>","PeriodicalId":100067,"journal":{"name":"AGU Advances","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023AV001002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139655150","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}