Journal of Geophysical Research: Solid Earth最新文献_第3页

The Deep Lithospheric Structure of Terrane Accretion as Revealed Through Patterns of Seismicity Associated With the Collision of the Panamá–Chocó Block and South America Beneath Cauca, Colombia 通过与哥伦比亚考卡地下Panamá-Chocó块体与南美碰撞相关的地震活动模式揭示地体增生的深部岩石圈结构

IF 3.9 2区地球科学

Journal of Geophysical Research: Solid Earth Pub Date : 2025-06-23 DOI: 10.1029/2024JB030067

Brandon T. Bishop, Linda M. Warren, Pablo Aravena, Sungwon Cho, Lillian Soto-Cordero, Patricia Pedraza, Germán A. Prieto, Viviana Dionicio

{"title":"The Deep Lithospheric Structure of Terrane Accretion as Revealed Through Patterns of Seismicity Associated With the Collision of the Panamá–Chocó Block and South America Beneath Cauca, Colombia","authors":"Brandon T. Bishop, Linda M. Warren, Pablo Aravena, Sungwon Cho, Lillian Soto-Cordero, Patricia Pedraza, Germán A. Prieto, Viviana Dionicio","doi":"10.1029/2024JB030067","DOIUrl":"https://doi.org/10.1029/2024JB030067","url":null,"abstract":"The Cauca region is the only documented site in the world where extensive intermediate depth seismicity occurs over multiple decades above a subducting slab. Here, the subducting Nazca oceanic plate descends beneath a mosaic of terranes derived from the Caribbean plate and accreted to continental South America from the Cretaceous to the present. Through relative relocation of >6,000 earthquakes from 2010 to 2019 we show that seismic activity within the Nazca slab is concentrated immediately inboard of the most recently accreted terrane (the Panamá–Chocó Block) and that supraslab seismicity is occurring within the subducted continuation of this terrane. The deepest extent of this seismicity occurs only within the Colombian forearc and a gap in the active volcanic arc, indicating that the continuation of this terrane at depth has perturbed the thermal structure of the subduction zone. This perturbation is likely what permits brittle failure to occur above the slab. Within the context of the long-term evolution of the Colombian subduction zone, this seismicity must represent either a transient phenomenon as the continuation of the Panamá–Chocó Block warms and becomes incorporated into the convecting mantle wedge or a site where fluids released by the subducting Nazca slab have been focused, promoting hydrofracture. While additional tests are necessary to distinguish between these possibilities, seismicity within the Nazca slab is most intense directly beneath the locations where supraslab seismicity is concentrated, consistent with hydrofracture due to fluids escaping the slab. Similar transient processes may have affected terrane accretion in the geologic past.","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144339553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Transient Propagation of Ductile Ruptures by Thermal Runaway 热失控下延性断裂的瞬态扩展

IF 3.9 2区地球科学

Journal of Geophysical Research: Solid Earth Pub Date : 2025-06-21 DOI: 10.1029/2025JB031240

A. Spang, M. Thielmann, A. de Montserrat, T. Duretz

{"title":"Transient Propagation of Ductile Ruptures by Thermal Runaway","authors":"A. Spang, M. Thielmann, A. de Montserrat, T. Duretz","doi":"10.1029/2025JB031240","DOIUrl":"https://doi.org/10.1029/2025JB031240","url":null,"abstract":"Ductile deformation is typically associated with slow and steady-state deformation, yet the occurrence of deep earthquakes, which exhibit a rapid and transient behavior, challenges this view. One proposed mechanism to facilitate such behavior is thermal runaway. However, two-dimensional (2D) models that capture highly localized, transient ductile deformation, driven by thermal runaway, remain unexplored. This study presents 2D simple shear models using the pseudo-transient relaxation method optimized for graphics processing units. The models incorporate a Maxwell rheology including compressible elasticity, diffusion creep, dislocation creep, and low-temperature plasticity. Our models capture the nucleation and transient propagation of highly localized ductile ruptures driven by thermal runaway. Depending on rheological parameters, we observe a spectrum of behaviors: (a) broad shear zones which deform only slightly faster than the boundary conditions; (b) localized deformation which is orders of magnitude faster than far field deformation; and (c) highly localized ruptures reaching seismic slip velocities. Runaway intensity scales with nondimensional numbers derived from 1D studies, but its spatial and temporal evolution is more complex, traversing several stages. The rupture front perturbs the local stress field, generating opposing pressure anomalies of up to 1.5 GPa. For mantle transition zone conditions, thermal runaway-driven ductile ruptures can reach seismic slip velocities, confirming it as a viable mechanism for deep-focus earthquakes. Under brittle-ductile transition zone conditions, our models capture thermal runaway driving accelerated creep which disturbs the local pressure field sufficiently to facilitate brittle failure in an otherwise ductile host rock.","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JB031240","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144331850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Interconnectivity of Magmatic and Hydrothermal Systems of Aluto Volcano in the Main Ethiopian Rift Inferred From Seismicity 从地震活动性推断埃塞俄比亚主裂谷Aluto火山岩浆和热液系统的连通性

IF 3.9 2区地球科学

Journal of Geophysical Research: Solid Earth Pub Date : 2025-06-20 DOI: 10.1029/2024JB031053

Tesfahiwet Yemane, Thomas Samuel Hudson, John Michael Kendall, Jonathan Blundy, Amdemichael Zafu Tadesse, James O. S. Hammond, Atalay Ayele, Ghebrebrhan Ogubazghi, Sacha Lapins

{"title":"Interconnectivity of Magmatic and Hydrothermal Systems of Aluto Volcano in the Main Ethiopian Rift Inferred From Seismicity","authors":"Tesfahiwet Yemane, Thomas Samuel Hudson, John Michael Kendall, Jonathan Blundy, Amdemichael Zafu Tadesse, James O. S. Hammond, Atalay Ayele, Ghebrebrhan Ogubazghi, Sacha Lapins","doi":"10.1029/2024JB031053","DOIUrl":"https://doi.org/10.1029/2024JB031053","url":null,"abstract":"Aluto volcano, situated in the central Main Ethiopian Rift (MER) within the northern part of the East African Rift System (EARS) is seismically active, with indications of unrest detected by InSAR. It hosts Ethiopia's first pilot project for geothermal energy. Despite extensive studies, uncertainties remain about the mechanisms of unrest and the existence of a shallow magma chamber beneath Aluto which could drive the hydrothermal system, and is crucial for understanding its geothermal potential. This study investigates Aluto's magmatic and hydrothermal systems using observations of seismicity in the region. We analyze seismic data from January 2012 to January 2014, locating 2,393 events, which lie predominantly along the Wonji Fault Belt (WFB). Event depths reach up to 40 km beneath Aluto, suggesting the presence of a highly crystallized body at shallow depth, consistent with previous magnetotelluric and gravity studies. Deep crustal seismicity likely relates to fluid and/or magmatic processes. High b-values of 1.97 ± 0.10 at Aluto indicates the presence of fluids. Seismicity is negligible beneath Silti Debre Zeyt Fault Zone (SDFZ), previously identified as a highly conductive, indicative of melt. Focal mechanisms show normal faulting in the direction of rift extension and full-moment tensor inversions suggest shear-failure with fluids potentially activating existing faults. We suggest that the magmatic and hydrothermal systems are connected through pre-existing faults. Understanding this interaction will enhance our knowledge of the geothermal system, volcanic risk, mechanisms of unrest, and emplacement of geothermal brines.","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB031053","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144323700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Slip Modes Along a Structurally-Driven Earthquake Barrier in Chile 智利结构驱动的地震屏障滑动模式

IF 3.9 2区地球科学

Journal of Geophysical Research: Solid Earth Pub Date : 2025-06-20 DOI: 10.1029/2024JB030796

Diego Molina-Ormazabal, Mathilde Radiguet, Jannes Münchmeyer, Nicolas Hernandez-Soto, Adrien Vezinet, Lea Pousse-Beltran, Catalina Castro, Marie-Pierre Doin, Juan Carlos Baez, Marcos Moreno, Andres Tassara, Philippe Durand, Anne Socquet

{"title":"Slip Modes Along a Structurally-Driven Earthquake Barrier in Chile","authors":"Diego Molina-Ormazabal, Mathilde Radiguet, Jannes Münchmeyer, Nicolas Hernandez-Soto, Adrien Vezinet, Lea Pousse-Beltran, Catalina Castro, Marie-Pierre Doin, Juan Carlos Baez, Marcos Moreno, Andres Tassara, Philippe Durand, Anne Socquet","doi":"10.1029/2024JB030796","DOIUrl":"https://doi.org/10.1029/2024JB030796","url":null,"abstract":"Oceanic ridges often collocate with seismic barriers and episodic aseismic slip. However, how subducted seafloor topography drives interactions between slow and fast slip remains unclear. Here, using GNSS, InSAR and seismicity, we show interactions between a deep slow slip event (SSE) and a nearby shallow earthquake sequence that occurred in 2020 in northern Chile. These events overlap with the subducted Copiapo ridge, which has served as a barrier for historical earthquake ruptures. Gravity field data and seismic tomography reveal that the SSE nucleated in a region hosting a subducted seamount. Six months later, the seismic sequence dynamically triggered the acceleration and migration of the deep SSE, while afterslip and aftershocks propagated up to another subducted seamount at shallower depth. Our findings suggest that subducted seamounts influence fault hydromechanics, where high pore-pressure and rate strengthening material promote continuous slip release, reducing slip deficit. This process is modulated by SSEs and low magnitude seismic sequences.","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB030796","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144323682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Are There Thermal Precursors to Eruptions Detectable by ASTER? Evaluating 22 years of Global Medium Resolution Satellite Thermal Observations at 200+ Volcanoes ASTER能探测到喷发的热前兆吗？评估22年来200多个火山的全球中分辨率卫星热观测

IF 3.9 2区地球科学

Journal of Geophysical Research: Solid Earth Pub Date : 2025-06-20 DOI: 10.1029/2024JB030427

A. Gomez-Patron, M. E. Pritchard, X. Peng, A. Downes, C. Crothers, J. Valenza, A. Wada, L. Way, L. Zapata

{"title":"Are There Thermal Precursors to Eruptions Detectable by ASTER? Evaluating 22 years of Global Medium Resolution Satellite Thermal Observations at 200+ Volcanoes","authors":"A. Gomez-Patron, M. E. Pritchard, X. Peng, A. Downes, C. Crothers, J. Valenza, A. Wada, L. Way, L. Zapata","doi":"10.1029/2024JB030427","DOIUrl":"https://doi.org/10.1029/2024JB030427","url":null,"abstract":"Measurements of temperature changes at volcanic features can reveal trends that could forecast eruptions. Using nighttime advanced spaceborne thermal emission and reflection radiometer observations with a spatial resolution of 90 m/pixel, we collect thermal measurements for 195 subaerial volcanoes that erupted at least once between 2000 and 2022 (810 eruptions) to evaluate for thermal precursors. Roughly 28% of eruptions (225) have sufficient nighttime cloud-free observations to construct a robust time series. We use our deviation from thermal time series baseline algorithm to identify temperature observations that vary from the preceding average by a specified number of standard deviations. In our data set, 23% of eruptions were preceded by an increase in temperature, 6% had a decrease in temperature, 15% had an increase-then-decrease trend, 55% had no detectable thermal precursor to eruption, and 69% of volcanoes had a volcanic thermal change not associated with an eruption. Thermal precursors can start as early as 8 years before an eruption to only a week; however, most precursors last less than a year. We also perform chi-square tests to compare precursors with volcanic and eruptive characteristics. We find that all kinds of thermal precursors are present in all volcanic and eruptive characteristics and the size and duration of the precursor do not indicate size of the subsequent eruption. Finally, we find several examples where more temporally dense satellite thermal observations at spatial resolution of 90 m/pixel or better are needed.","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144323683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Narrow Magma Conduit of the Changbaishan Volcano Revealed by High-Resolution Receiver Function Imaging 高分辨率接收函数成像揭示长白山火山狭窄岩浆通道

IF 3.9 2区地球科学

Journal of Geophysical Research: Solid Earth Pub Date : 2025-06-20 DOI: 10.1029/2024JB030535

Dong Yan, You Tian, Dapeng Zhao

{"title":"A Narrow Magma Conduit of the Changbaishan Volcano Revealed by High-Resolution Receiver Function Imaging","authors":"Dong Yan, You Tian, Dapeng Zhao","doi":"10.1029/2024JB030535","DOIUrl":"https://doi.org/10.1029/2024JB030535","url":null,"abstract":"The Changbaishan volcano (CBV) is the largest Cenozoic intraplate stratovolcano in Northeast China. Although many seismic imaging studies have been conducted in the CBV area during the past two decades, the detailed crustal structure beneath the Tianchi caldera is still poorly understood due to the sparse seismic observations limited by the harsh natural conditions. In this study, we deployed dense linear seismic arrays along three slopes of the Changbaishan-Tianchi volcanic area for the first time to obtain unprecedented high-resolution images of the crustal structure by using the teleseismic receiver-function imaging technique. Our results reveal detailed variations of crustal interface characteristics beneath the Tianchi caldera and adjacent areas. Several intracrustal interfaces are clearly revealed that correspond well to geological bodies, which might indicate boundaries of consolidated igneous bodies related to the primitive magmatic activities. A continuous Moho discontinuity at ∼37 km depth is revealed, whereas a weak Moho zone with a vertical offset of ∼4 km appears directly beneath the Tianchi caldera, which shows a clear positive correlation with the average crustal Vp/Vs ratio. We deem that the prominent crustal thickening and the higher Vp/Vs ratio beneath the Tianchi caldera might be closely associated with the complicated mantle-derived mafic materials underplating at the crust-mantle boundary. The joint effect of the multilevel magmatic plumbing system and a narrow magma conduit beneath the Tianchi caldera could account for the distinctive bimodal volcanic eruption history of the CBV.","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB030535","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144331881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Influence of Normal Stress, Shear Velocity and Materials on Steady-State Shear Resistance and Viscosity of Rapid Dry Granular Flows 法向应力、剪切速度和物料对快速干燥颗粒流稳态剪切阻力和粘度的影响

IF 3.9 2区地球科学

Journal of Geophysical Research: Solid Earth Pub Date : 2025-06-20 DOI: 10.1029/2025JB031305

Wei Hu, Yan Li, Huaixiao Gou, Xiaoping Jia, Li Zhou, Chingshung Chang

{"title":"Influence of Normal Stress, Shear Velocity and Materials on Steady-State Shear Resistance and Viscosity of Rapid Dry Granular Flows","authors":"Wei Hu, Yan Li, Huaixiao Gou, Xiaoping Jia, Li Zhou, Chingshung Chang","doi":"10.1029/2025JB031305","DOIUrl":"https://doi.org/10.1029/2025JB031305","url":null,"abstract":"Understanding the rheological behavior of rapid granular flows is crucial for understanding various geological processes, such as fast fault slip and rapid motion of landslides. In this study, we conducted rotary shear experiments on different granular materials, spanning a range of shear velocities from slow to rapid and under varying normal stresses, to investigate the evolution of mechanical behavior under different flow conditions. The experimental results showed that steady-state shear resistance varied with normal stress and material composition at shear velocities below 1 m/s. A consistent velocity-dependent trend was observed. The steady-state shear resistance of the sample experienced a transition from velocity-strengthening behavior at low shear velocities (below 0.1 m/s) to velocity-weakening behavior at higher shear velocities (above 0.1 m/s). Interestingly, at shear velocities exceeding 1 m/s, the steady-state shear resistance became independent of normal stress and material composition, converging to a similar steady-state value for both crushable and uncrushable materials. Although normal stress and mineral composition had a limited influence on steady-state shear resistance at high shear rates, they significantly affected the weakening rate (the transition from peak strength to steady-state shear resistance), which was strongly correlated with the material's crushing ability, as characterized by the Weibull modulus. These findings provide insights into the mechanisms governing the hypermobility of mega-landslides and the rapid dynamics of geological flows.","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144331880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Transient and Steady-State Dislocation Creep of Olivine Controlled by Dislocation Interactions at the Isostress Endmember 等应力端位错相互作用控制橄榄石的瞬态和稳态位错蠕变

IF 3.9 2区地球科学

Journal of Geophysical Research: Solid Earth Pub Date : 2025-06-19 DOI: 10.1029/2024JB030606

David Wallis, Thomas Breithaupt, Taco Broerse

{"title":"Transient and Steady-State Dislocation Creep of Olivine Controlled by Dislocation Interactions at the Isostress Endmember","authors":"David Wallis, Thomas Breithaupt, Taco Broerse","doi":"10.1029/2024JB030606","DOIUrl":"https://doi.org/10.1029/2024JB030606","url":null,"abstract":"The rheological behavior of olivine deforming by dislocation creep controls geodynamic processes that involve steady-state flow or transient viscosity evolution. Longstanding rheological models applied to both contexts assume that dislocation creep of olivine aggregates occurs close to the isostrain endmember with each grain deforming to the same strain but supporting different stress. Here, we test this assumption by constructing isostrain and isostress models based on flow laws for single crystals and comparing them to rheological data from aggregates. This analysis reveals that strain rates measured on olivine aggregates agree with those predicted by the isostress model but are an order of magnitude faster than those predicted by the isostrain model. When extrapolated to conditions typical of the shallow upper mantle, the isostress model predicts steady-state viscosities that are one to three orders of magnitude less than those predicted by the isostrain model. Furthermore, deformation close to the isostress endmember implies that transient creep occurs predominantly by dislocation interactions, suggesting viscosity changes that are approximately one order of magnitude greater than those predicted previously based on grain interactions associated with the isostrain model.","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB030606","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Shallow Fault Zone Structure Affects Rupture Dynamics and Ground Motions of the 2019 Ridgecrest Sequence to Regional Distances 浅层断裂带结构在区域距离上对2019年脊峰序列破裂动力学和地面运动的影响

IF 3.9 2区地球科学

Journal of Geophysical Research: Solid Earth Pub Date : 2025-06-19 DOI: 10.1029/2025JB031194

Nico Schliwa, Alice-Agnes Gabriel, Yehuda Ben-Zion

{"title":"Shallow Fault Zone Structure Affects Rupture Dynamics and Ground Motions of the 2019 Ridgecrest Sequence to Regional Distances","authors":"Nico Schliwa, Alice-Agnes Gabriel, Yehuda Ben-Zion","doi":"10.1029/2025JB031194","DOIUrl":"https://doi.org/10.1029/2025JB031194","url":null,"abstract":"Seismic faults are surrounded by damaged rocks with reduced rigidity and enhanced attenuation. These damaged fault zone structures can amplify seismic waves and affect earthquake dynamics, yet they are typically omitted in physics-based regional ground motion simulations. We report on the significant effects of a shallow, flower-shaped fault zone in foreshock-mainshock 3D dynamic rupture models of the 2019 Ridgecrest earthquake sequence. We find that the fault zone structure both amplifies and reduces ground motions not only locally but at distances exceeding 100 km. This impact on ground motions is frequency- and magnitude-dependent, particularly affecting higher frequency ground motions from the foreshock because its corner frequency is closer to the fault zone's fundamental eigenfrequency. Within the fault zone, the shallow transition to a velocity-strengthening frictional regime leads to a depth-dependent peak slip rate increase of up to 70% and confines fault zone-induced supershear transitions mostly to the fault zone's velocity-weakening roots. However, the interplay of fault zone waves, free surface reflections, and rupture directivity can generate localized supershear rupture, even in narrow velocity-strengthening regions, which are typically thought to inhibit supershear rupture. This study demonstrates that shallow fault zone structures may significantly affect intermediate- and far-field ground motions and cause localized supershear rupture penetrating into velocity-strengthening regions, with important implications for seismic hazard assessment.","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JB031194","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Long-Time Delays in Induced Earthquakes Caused by Low-Permeability Bodies: Insights From the Xinfengjiang Reservoir, China 低渗透体诱发地震的长时间延迟：来自新丰江水库的启示

IF 3.9 2区地球科学

Journal of Geophysical Research: Solid Earth Pub Date : 2025-06-18 DOI: 10.1029/2024JB030579

Lipeng He, Zhen Guo, Bin Luo, Qipeng Bai, Guangyao Yin, Keyuan Wu, Abayomi Gaius Osotuyi, Liwei Wang

{"title":"Long-Time Delays in Induced Earthquakes Caused by Low-Permeability Bodies: Insights From the Xinfengjiang Reservoir, China","authors":"Lipeng He, Zhen Guo, Bin Luo, Qipeng Bai, Guangyao Yin, Keyuan Wu, Abayomi Gaius Osotuyi, Liwei Wang","doi":"10.1029/2024JB030579","DOIUrl":"10.1029/2024JB030579","url":null,"abstract":"In many cases of induced seismicity, earthquakes occur significantly delayed to the initiation of industrial activities, yet the mechanisms behind these long-time delays remain poorly understood. In the Xinfengjiang Reservoir, an earthquake swarm became active in 2010, nearly 50 years after the initial impoundment in 1959. In this study, we conducted high-resolution 3D velocity tomography and focal mechanism analysis using a dense local seismic network. High-resolution seismic imaging identifies two downward migration channels enabling fluids to infiltrate the bedrock and low Vp/Vs anomalies at 5–10 km corresponding to low-permeability granitic bodies. Numerical simulations indicate that these Vp/Vs anomalies can delay pore-pressure diffusion by decades, resulting in delayed triggering of seismic events in the northwest of the reservoir. Our findings highlight the critical influence of low-permeability bodies in controlling the spatial-temporal evolution of reservoir-induced earthquakes and underscore the need to reconsider long-term seismic risk assessments for reservoirs situated in similar geological settings.","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"130 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144312064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0