The westward subduction of the Pacific plate has induced lithosphere weakening, intraplate volcanism, thermal and compositional variation in the East Asian continent since the Mesozoic. However, how the intracontinental deformation corresponds to this subduction-induced lithospheric architecture remains enigmatic. Here we employ an integrated geophysical-petrological approach to explore the lithospheric structure, thermal regime, and rheology beneath Northeast (NE) China, constrained by seismicity distribution. We find significant lithospheric thinning on the eastern side of the North-South Gravity Lineament (NSGL). We also identify a cold, dry, and rheologically strong crust west of the NSGL, contrasting with a hot, wet, and rheologically weak crust to the east. We confirm that the NSGL potentially marks a tectonic boundary, influenced by continental contraction and orogeny during the Mongol-Okhotsk Ocean closure in the west and the hydrous upwelling of the subducted Pacific slab in the east.
{"title":"Contrasting Crustal Rheology and Seismicity in Northeast China: Far-Field Responses to the Pacific Plate Subduction","authors":"Peng Yang, Shaowen Liu","doi":"10.1029/2024jb031051","DOIUrl":"https://doi.org/10.1029/2024jb031051","url":null,"abstract":"The westward subduction of the Pacific plate has induced lithosphere weakening, intraplate volcanism, thermal and compositional variation in the East Asian continent since the Mesozoic. However, how the intracontinental deformation corresponds to this subduction-induced lithospheric architecture remains enigmatic. Here we employ an integrated geophysical-petrological approach to explore the lithospheric structure, thermal regime, and rheology beneath Northeast (NE) China, constrained by seismicity distribution. We find significant lithospheric thinning on the eastern side of the North-South Gravity Lineament (NSGL). We also identify a cold, dry, and rheologically strong crust west of the NSGL, contrasting with a hot, wet, and rheologically weak crust to the east. We confirm that the NSGL potentially marks a tectonic boundary, influenced by continental contraction and orogeny during the Mongol-Okhotsk Ocean closure in the west and the hydrous upwelling of the subducted Pacific slab in the east.","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"46 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2026-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147360967","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}
Pull-apart basins (PABs) commonly develop within extensional step-overs along strike-slip faults, but their effect in determining rupture behaviors across step-overs remains obscure. Constrained by field observations, we design parallelogram-shaped PAB models and conduct three-dimensional dynamic rupture simulations under uniform and depth-dependent stress regimes. Our results show that PABs greatly enhance rupture jumping capability across step-overs, especially for the 8 km-depth deep basin models, the average basin depth of the Dead Sea Basin. The PAB reduces the critical nucleation length and promotes rupture nucleation on the second fault, particularly under depth-dependent stress with lower strength. We identify three different patterns of average rupture velocity distribution on the second fault, correlated with different source time function patterns. Localized super-shear patches are commonly observed on the second fault in the depth-dependent regime, where secondary-fault nucleation shows a clear dependence on the overlap distance. The stopping phase at the termination of the main fault plays a critical role in rupture jumping capability across step-overs. In the presence of PABs, the basin amplification effect, together with a secondary contribution from the bi-material interface, further enhances jumping capability, since both the main fault and the second fault are embedded in bi-material media at the PAB region. We also discuss a conceptual evolution-based PAB model incorporating the Y-shape flower structure fault geometry, highlighting its potential in explaining the large rupture jumping distance observed in natural fault systems.
{"title":"Enhanced Earthquake Rupture Jumping Distance Across Step-Overs With Pull-Apart Basin: Insights From Observation-Constrained 3-D Dynamic Rupture Simulations","authors":"Zeyu Lu, Feng Hu","doi":"10.1029/2025jb032114","DOIUrl":"https://doi.org/10.1029/2025jb032114","url":null,"abstract":"Pull-apart basins (PABs) commonly develop within extensional step-overs along strike-slip faults, but their effect in determining rupture behaviors across step-overs remains obscure. Constrained by field observations, we design parallelogram-shaped PAB models and conduct three-dimensional dynamic rupture simulations under uniform and depth-dependent stress regimes. Our results show that PABs greatly enhance rupture jumping capability across step-overs, especially for the 8 km-depth deep basin models, the average basin depth of the Dead Sea Basin. The PAB reduces the critical nucleation length and promotes rupture nucleation on the second fault, particularly under depth-dependent stress with lower strength. We identify three different patterns of average rupture velocity distribution on the second fault, correlated with different source time function patterns. Localized super-shear patches are commonly observed on the second fault in the depth-dependent regime, where secondary-fault nucleation shows a clear dependence on the overlap distance. The stopping phase at the termination of the main fault plays a critical role in rupture jumping capability across step-overs. In the presence of PABs, the basin amplification effect, together with a secondary contribution from the bi-material interface, further enhances jumping capability, since both the main fault and the second fault are embedded in bi-material media at the PAB region. We also discuss a conceptual evolution-based PAB model incorporating the Y-shape flower structure fault geometry, highlighting its potential in explaining the large rupture jumping distance observed in natural fault systems.","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"74 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2026-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147359999","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}
Daniel Carbajal-Martínez, Christoph Wanner, Loïc Peiffer, Larryn W. Diamond
Amagmatic geothermal systems in coastal locations are promising energy resources, yet the processes that localize and sustain their hot-spring discharge remain unclear. We investigate La Jolla Beach (NW Baja California, Mexico)—one of the hottest known examples worldwide (∼100°C)—using large-scale 3D coupled thermal–hydraulic simulations. The models are calibrated against observed temperature, salinity, surface area and location of the springs, and verified using meteoric-water residence times. The results imply that a highly permeable coastal segment of the Agua Blanca Fault (ABF) transfers meteoric water from a hinterland recharge zone to the coast via deep (>5 km) circulation. Within the coastal fault, dense seawater forms a hydraulic barrier to the meteoric water, while thermal buoyancy steepens the meteoric–seawater interface and creates a near-vertical upflow plume that focuses hot, mixed fluids to the shoreline, resulting in high discharge temperatures. Tracer simulations indicate that deep fault flow is supplied approximately equally by infiltration through the exposed fault trace and by lateral inflow from the surrounding fractured country rocks. This underscores the system's inherently 3D nature and the capacity of regional faults to collect recharge from broad catchments, even where overall infiltration rates are low. Permeable sediments draped over a basement high and bounded by less-permeable sediments focus the hot upwelling water at La Jolla Beach. Our findings explain the thermal-hydraulic coupling that controls amagmatic coastal fault–controlled geothermal systems, providing a basis to assess the geothermal potential of analogous systems worldwide.
{"title":"Behavior of Coastal Amagmatic Geothermal Systems: Thermal–Hydraulic Modeling Insights From La Jolla Beach, Baja California, Mexico","authors":"Daniel Carbajal-Martínez, Christoph Wanner, Loïc Peiffer, Larryn W. Diamond","doi":"10.1029/2025jb033188","DOIUrl":"https://doi.org/10.1029/2025jb033188","url":null,"abstract":"Amagmatic geothermal systems in coastal locations are promising energy resources, yet the processes that localize and sustain their hot-spring discharge remain unclear. We investigate La Jolla Beach (NW Baja California, Mexico)—one of the hottest known examples worldwide (∼100°C)—using large-scale 3D coupled thermal–hydraulic simulations. The models are calibrated against observed temperature, salinity, surface area and location of the springs, and verified using meteoric-water residence times. The results imply that a highly permeable coastal segment of the Agua Blanca Fault (ABF) transfers meteoric water from a hinterland recharge zone to the coast via deep (>5 km) circulation. Within the coastal fault, dense seawater forms a hydraulic barrier to the meteoric water, while thermal buoyancy steepens the meteoric–seawater interface and creates a near-vertical upflow plume that focuses hot, mixed fluids to the shoreline, resulting in high discharge temperatures. Tracer simulations indicate that deep fault flow is supplied approximately equally by infiltration through the exposed fault trace and by lateral inflow from the surrounding fractured country rocks. This underscores the system's inherently 3D nature and the capacity of regional faults to collect recharge from broad catchments, even where overall infiltration rates are low. Permeable sediments draped over a basement high and bounded by less-permeable sediments focus the hot upwelling water at La Jolla Beach. Our findings explain the thermal-hydraulic coupling that controls amagmatic coastal fault–controlled geothermal systems, providing a basis to assess the geothermal potential of analogous systems worldwide.","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"94 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147329823","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}
D. Granieri, M. Cerminara, F. Mazzarini, R. Novellino, M. Trolese, E. Dallara, M. Lelli
The Larderello-Travale area in the northern Apennines of Italy hosts the world's oldest exploited geothermal field. Its success lies primarily in the presence of an extraordinary geothermal resource housed in a large vapor-dominated fractured reservoir that produces superheated steam. We present results from an integrated study at Le Biancane area (∼80,000 m2) in the southern sector of the Larderello-Travale geothermal field, where the impermeable caprock is absent and the shallowest reservoir outcrops. Maps of soil diffuse CO2 and soil temperature, based on measurements at 345 locations, highlight focused zones of high CO2 flux (>500 g m−2 day−1) and soil temperature (>60°C), likely controlled by NNE-SSW and NE-SW trending fractures and normal to strike-slip faults. Convective heat flux from high-enthalpy vapor is estimated using the H2O/CO2 molar ratio of local fumaroles and the total CO2 output (∼10 t day−1) as a degassing tracer. The field study is supplemented by laboratory measurements of soil properties (thermal conductivity, porosity, water and air content, bulk and solid-phase densities). Combined data sets allow us to demonstrate that the heat associated with the ascent and condensation of vapor is predominantly transferred by conduction in the uppermost portion of the soil at Le Biancane, generating linear thermal profiles, which we measured in 41 locations. Ultimately, the analysis of the heat exchange within the soil and its dynamic interaction with the atmosphere offers a clearer understanding of the relative roles of the various heat flux components in a vapor-dominated geothermal field.
意大利亚平宁山脉北部的Larderello-Travale地区拥有世界上最古老的地热田。它的成功主要在于一个巨大的蒸汽为主的裂缝性储层中存在一种非凡的地热资源，可以产生过热的蒸汽。我们介绍了在Larderello-Travale地热田南段的Le Biancane地区（~ 80000 m2）进行的综合研究结果，该地区没有不透水盖层，并且露出了最浅的储层。根据345个地点的测量结果绘制的土壤扩散CO2和土壤温度图，突出了高CO2通量（>500 g m−2 day−1）和土壤温度（>60°C）的集中区域，可能受NNE-SSW和NE-SW走向的裂缝以及正常到走滑断层的控制。利用局部喷气孔的H2O/CO2摩尔比和总CO2输出（~ 10 t day - 1）作为脱气示踪剂，估算了来自高焓蒸汽的对流热通量。实地研究还辅以土壤特性的实验室测量（热导率、孔隙度、水和空气含量、体积和固相密度）。综合数据集使我们能够证明，与蒸汽上升和凝结有关的热量主要通过传导在勒比安坎土壤的最上层传递，产生线性热剖面，我们在41个地点测量了这一点。最后，通过对土壤内部热交换及其与大气的动态相互作用的分析，可以更清楚地了解在以蒸汽为主的地热场中各种热通量分量的相对作用。
{"title":"Quantifying Gas and Thermal Energy Emissions in an Active Geothermal Area: Insights From Le Biancane (Larderello Field, Italy)","authors":"D. Granieri, M. Cerminara, F. Mazzarini, R. Novellino, M. Trolese, E. Dallara, M. Lelli","doi":"10.1029/2025jb031961","DOIUrl":"https://doi.org/10.1029/2025jb031961","url":null,"abstract":"The Larderello-Travale area in the northern Apennines of Italy hosts the world's oldest exploited geothermal field. Its success lies primarily in the presence of an extraordinary geothermal resource housed in a large vapor-dominated fractured reservoir that produces superheated steam. We present results from an integrated study at Le Biancane area (∼80,000 m<sup>2</sup>) in the southern sector of the Larderello-Travale geothermal field, where the impermeable caprock is absent and the shallowest reservoir outcrops. Maps of soil diffuse CO<sub>2</sub> and soil temperature, based on measurements at 345 locations, highlight focused zones of high CO<sub>2</sub> flux (>500 g m<sup>−2</sup> day<sup>−1</sup>) and soil temperature (>60°C), likely controlled by NNE-SSW and NE-SW trending fractures and normal to strike-slip faults. Convective heat flux from high-enthalpy vapor is estimated using the H<sub>2</sub>O/CO<sub>2</sub> molar ratio of local fumaroles and the total CO<sub>2</sub> output (∼10 <i>t</i> day<sup>−1</sup>) as a degassing tracer. The field study is supplemented by laboratory measurements of soil properties (thermal conductivity, porosity, water and air content, bulk and solid-phase densities). Combined data sets allow us to demonstrate that the heat associated with the ascent and condensation of vapor is predominantly transferred by conduction in the uppermost portion of the soil at Le Biancane, generating linear thermal profiles, which we measured in 41 locations. Ultimately, the analysis of the heat exchange within the soil and its dynamic interaction with the atmosphere offers a clearer understanding of the relative roles of the various heat flux components in a vapor-dominated geothermal field.","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"41 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2026-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147320153","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}
Tectonic faults can slip in a spectrum of fault slip behaviors, from aseismic slip and slow ruptures to elasto-dynamic earthquakes. Following frictional theory, laboratory experiments have shown that the basic ingredient that may control this transition is the interaction between the fault stiffness and the surrounding elastic medium. We aim at investigating the role of the loading stiffness on the seismic cycles in granular fault simulations. For this purpose, we build a numerical model based on the Discrete Element Method, inspired by laboratory friction experiments on fault gouge in the presence of an elastic loading system. The coupling between fault granular rheology and surrounding rock elasticity leads to seismic cycles with properties that are strongly influenced by the loading stiffness. Stiff fault systems generally produce frequent compactional events with limited sliding distances and low to moderate stress drops, while soft fault systems generally produce rare dilatational events with large sliding distances and stress drops. We show that, on average, simulated events are well-described by a simple linear slip-weakening friction law, but the weakening rate that best describes the events is tightly coupled with the loading stiffness. This contradicts the idea of an intrinsic friction law for the granular gouge layer and demonstrates the need to consider a fault as a tribological system coupling the scales of the granular gouge and of the elastic surrounding medium.
{"title":"Influence of the Loading Stiffness on Sheared Granular Fault Gouge, and Applicability to Slip-Weakening Theory","authors":"Guilhem Mollon, Nathalie Casas, Marco Scuderi","doi":"10.1029/2025jb032076","DOIUrl":"https://doi.org/10.1029/2025jb032076","url":null,"abstract":"Tectonic faults can slip in a spectrum of fault slip behaviors, from aseismic slip and slow ruptures to elasto-dynamic earthquakes. Following frictional theory, laboratory experiments have shown that the basic ingredient that may control this transition is the interaction between the fault stiffness and the surrounding elastic medium. We aim at investigating the role of the loading stiffness on the seismic cycles in granular fault simulations. For this purpose, we build a numerical model based on the Discrete Element Method, inspired by laboratory friction experiments on fault gouge in the presence of an elastic loading system. The coupling between fault granular rheology and surrounding rock elasticity leads to seismic cycles with properties that are strongly influenced by the loading stiffness. Stiff fault systems generally produce frequent compactional events with limited sliding distances and low to moderate stress drops, while soft fault systems generally produce rare dilatational events with large sliding distances and stress drops. We show that, on average, simulated events are well-described by a simple linear slip-weakening friction law, but the weakening rate that best describes the events is tightly coupled with the loading stiffness. This contradicts the idea of an intrinsic friction law for the granular gouge layer and demonstrates the need to consider a fault as a tribological system coupling the scales of the granular gouge and of the elastic surrounding medium.","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"187 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2026-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147319714","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}
The composition of Earth's inner core remains unresolved, as pure Fe-Ni alloys cannot fully explain its observed density and seismic wave velocities. While the light elements including hydrogen, carbon, oxygen, sulfur and silicon (H, C, O, S and Si) have been invoked to reconcile these discrepancies, most previous studies have been limited to systems containing one or two light elements, leaving the full range of viable compositions unexplored. We employ ab initio calculations augmented by machine-learned force fields (MLFFs) to systematically investigate the elastic properties of hexagonal-close-packed (hcp)-Fe-light element alloys under inner core conditions. Using a solid solution model parameterized with binary alloy data, we reveal a striking diversity of seismically viable compositions, including previously unrecognized ternary (e.g., Fe-Si-O, Fe-C-H, Fe-O-H) and even senary combinations. This flexibility arises primarily from the strong softening effects of superionic C and O, which dominate elastic behavior despite their low concentrations. While we predict a strict total concentration of the light elements (10–25 mol%), we demonstrate that elasticity alone imposes a much weaker constraint on inner core composition than previously assumed: millions of distinct hcp-Fe-light -element combinations satisfy seismic observations from the Preliminary Reference Earth Model (PREM). This suggests that determining the precise inner core composition must rely more heavily on thermodynamic constraints, as well as independent seismological observations such as partitioning behavior from the outer core, melting relationships, and seismic anisotropy.
地球内核的组成仍然没有解决，因为纯铁镍合金不能完全解释其观测到的密度和地震波速度。虽然包括氢、碳、氧、硫和硅（H、C、O、S和Si）在内的轻元素被用来调和这些差异，但大多数先前的研究仅限于含有一种或两种轻元素的系统，而没有探索完整的可行成分。本文采用基于机器学习力场（MLFFs）的从头计算方法，系统地研究了六边形紧堆积(hcp)- fe轻元素合金在内核条件下的弹性性能。使用二元合金数据参数化的固溶体模型，我们揭示了地震可行成分的惊人多样性，包括以前未被识别的三元（例如，Fe-Si-O, Fe-C-H, Fe-O-H）甚至二元组合。这种柔韧性主要来自超离子C和O的强烈软化作用，尽管它们的浓度很低，但它们主导了弹性行为。虽然我们预测了严格的轻元素总浓度（10-25 mol%），但我们证明了弹性本身对内核组成的约束比以前假设的要弱得多：数百万种不同的hcp- fe -轻元素组合满足初步参考地球模型（PREM）的地震观测结果。这表明，确定精确的内核组成必须更多地依赖于热力学约束，以及独立的地震学观测，如与外核的划分行为、熔化关系和地震各向异性。
{"title":"Extensive Models for Seismically Viable Inner Core Compositions Featuring Light Element Variations","authors":"Qianxi Chen, Feiwu Zhang, Joshua M. R. Muir","doi":"10.1029/2026jb033776","DOIUrl":"https://doi.org/10.1029/2026jb033776","url":null,"abstract":"The composition of Earth's inner core remains unresolved, as pure Fe-Ni alloys cannot fully explain its observed density and seismic wave velocities. While the light elements including hydrogen, carbon, oxygen, sulfur and silicon (H, C, O, S and Si) have been invoked to reconcile these discrepancies, most previous studies have been limited to systems containing one or two light elements, leaving the full range of viable compositions unexplored. We employ ab initio calculations augmented by machine-learned force fields (MLFFs) to systematically investigate the elastic properties of hexagonal-close-packed (hcp)-Fe-light element alloys under inner core conditions. Using a solid solution model parameterized with binary alloy data, we reveal a striking diversity of seismically viable compositions, including previously unrecognized ternary (e.g., Fe-Si-O, Fe-C-H, Fe-O-H) and even senary combinations. This flexibility arises primarily from the strong softening effects of superionic C and O, which dominate elastic behavior despite their low concentrations. While we predict a strict total concentration of the light elements (10–25 mol%), we demonstrate that elasticity alone imposes a much weaker constraint on inner core composition than previously assumed: millions of distinct hcp-Fe-light -element combinations satisfy seismic observations from the Preliminary Reference Earth Model (PREM). This suggests that determining the precise inner core composition must rely more heavily on thermodynamic constraints, as well as independent seismological observations such as partitioning behavior from the outer core, melting relationships, and seismic anisotropy.","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"26 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2026-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147319809","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}
The Qilian Shan, located at the northeastern edge of the Tibetan Plateau (NETP), has undergone complex tectonic evolution and serves as an ideal region for studying the growth of the Tibetan Plateau. However, the mode of lithospheric deformation beneath the Qilian Shan remains a subject of debate. In this study, we use the common conversion point stacking technique with P and S receiver functions, calculated from waveform data recorded by a seismic array consisting of 153 broadband stations, to obtain images of crustal and upper mantle discontinuities beneath the NETP and adjacent Alxa block. Our findings reveal that the Moho depth beneath the NETP is greater than that beneath the Alxa block, with the deepest Moho located beneath the North Qilian area. A sudden decrease of ∼10 km in the Moho depth occurs from the North Qilian fault to the Alxa block. The lithosphere-asthenosphere boundary is clearly identifiable in our data, showing a continuous, southward-dipping interface from the Alxa block to the Qilian Shan. Integrating geophysical and geological results, we propose that passive underthrusting of the Asian Plate occurs beneath the Qilian Shan. This process, influenced by the strong obstruction of the Alxa block during the expansion of the NETP, leads to the accumulation of lithospheric mantle material and crustal thickening and causing the lithospheric mantle of the Asian Plate to bend and undergo southward underthrusting beneath the Qilian Shan.
{"title":"Limited Passive Lithospheric Underthrusting and Localized Crustal Thickening Beneath the Qilian Shan, Northeastern Tibetan Plateau: Evidence From Receiver Function Imaging","authors":"Yifang Chen, Jiuhui Chen, Yu Li, Panpan Zhao, Biao Guo, Shuncheng Li","doi":"10.1029/2025jb033455","DOIUrl":"https://doi.org/10.1029/2025jb033455","url":null,"abstract":"The Qilian Shan, located at the northeastern edge of the Tibetan Plateau (NETP), has undergone complex tectonic evolution and serves as an ideal region for studying the growth of the Tibetan Plateau. However, the mode of lithospheric deformation beneath the Qilian Shan remains a subject of debate. In this study, we use the common conversion point stacking technique with P and S receiver functions, calculated from waveform data recorded by a seismic array consisting of 153 broadband stations, to obtain images of crustal and upper mantle discontinuities beneath the NETP and adjacent Alxa block. Our findings reveal that the Moho depth beneath the NETP is greater than that beneath the Alxa block, with the deepest Moho located beneath the North Qilian area. A sudden decrease of ∼10 km in the Moho depth occurs from the North Qilian fault to the Alxa block. The lithosphere-asthenosphere boundary is clearly identifiable in our data, showing a continuous, southward-dipping interface from the Alxa block to the Qilian Shan. Integrating geophysical and geological results, we propose that passive underthrusting of the Asian Plate occurs beneath the Qilian Shan. This process, influenced by the strong obstruction of the Alxa block during the expansion of the NETP, leads to the accumulation of lithospheric mantle material and crustal thickening and causing the lithospheric mantle of the Asian Plate to bend and undergo southward underthrusting beneath the Qilian Shan.","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"247 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2026-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147319713","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}
Submarine landslide runout influences the catastrophic impact of sediment mobilization on seafloor infrastructure, yet the basal slip processes that control runout remain poorly understood due to limited observations. This study examines the evolution and kinematics of a giant Pleistocene Mass Transport Complex (MTC) in the Taranaki Basin, located west of New Zealand's North Island. Using a regional grid of 2D seismic data, we refined its spatial extent and identified four distinct failure sectors (A–D) exhibiting remarkable differences in runout. MTC A, the largest debris flow deposit, covers ∼16,500 km2 with a ∼345 km runout. In contrast, MTC D is a frontally emergent slide with a shorter runout of 55 km. A 3D seismic reflection volume reveals MTC D as a coherent, internally faulted slide block showing a frontal ramp, thrusts, pop-up structures, and inverted normal faults. The basal shear surface (BSS) of MTC D lies within a turbidite layer above an earlier MTC. During MTC D sliding, shear softening partially remobilized the underlying MTC, which was subsequently incorporated into the overlying slide block of MTC D. We propose that the remobilized material behaved like a viscous mud, migrating away from high-pressure areas and welding the overlying faulted blocks to the BSS. The resulting high-friction zones at the BSS effectively arrested the movement of MTC D. Our findings present a new conceptual model showing how pre-existing MTCs can influence subsequent sliding processes. This has implications for tsunamigenic hazard assessments, as treating multi-phase failures as single events may overestimate tsunami potential.
{"title":"New Insights Into Basal Slip Processes and Kinematics of a Giant Pleistocene Submarine Mass Transport Complex, West of New Zealand's North Island","authors":"Ishika Bhattacharya, Sudipta Sarkar, Utpal Singh, Suzanne Bull, Malcolm Arnot, Jhanvee Khanna","doi":"10.1029/2025jb031830","DOIUrl":"https://doi.org/10.1029/2025jb031830","url":null,"abstract":"Submarine landslide runout influences the catastrophic impact of sediment mobilization on seafloor infrastructure, yet the basal slip processes that control runout remain poorly understood due to limited observations. This study examines the evolution and kinematics of a giant Pleistocene Mass Transport Complex (MTC) in the Taranaki Basin, located west of New Zealand's North Island. Using a regional grid of 2D seismic data, we refined its spatial extent and identified four distinct failure sectors (A–D) exhibiting remarkable differences in runout. MTC A, the largest debris flow deposit, covers ∼16,500 km<sup>2</sup> with a ∼345 km runout. In contrast, MTC D is a frontally emergent slide with a shorter runout of 55 km. A 3D seismic reflection volume reveals MTC D as a coherent, internally faulted slide block showing a frontal ramp, thrusts, pop-up structures, and inverted normal faults. The basal shear surface (BSS) of MTC D lies within a turbidite layer above an earlier MTC. During MTC D sliding, shear softening partially remobilized the underlying MTC, which was subsequently incorporated into the overlying slide block of MTC D. We propose that the remobilized material behaved like a viscous mud, migrating away from high-pressure areas and welding the overlying faulted blocks to the BSS. The resulting high-friction zones at the BSS effectively arrested the movement of MTC D. Our findings present a new conceptual model showing how pre-existing MTCs can influence subsequent sliding processes. This has implications for tsunamigenic hazard assessments, as treating multi-phase failures as single events may overestimate tsunami potential.","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"1 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2026-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147334699","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}
John M. Aiken, Fabian Barras, François Renard, Greg Hirth, Peter B. Kelemen, Robert A. Sohn
Peridotite rocks are primary targets for engineered geological carbon sequestration efforts because the carbon in -bearing fluids is transferred to the rock in the form of carbonate minerals during alteration reactions. Sequestration efforts must necessarily open fractures in the rocks surrounding a pumped borehole, but the current understanding of fracture growth during serpentinization of peridotite is limited to theoretical models and laboratory experiments on small samples. We deployed hydrophone arrays in peridotite boreholes established by the Oman Drilling Program and detected downward migrating fracture swarms that represent the first field observations of fracture growth in a serpentinizing rock. More than 2 years after the boreholes were established, we detected four, downward migrating tensile fracture swarms during an interval of elevated pore pressure following large rain events. All of the swarms occurred within a partially confined section of the local aquifer, beginning at a depth of 170 m and migrating to the bottom of the 400 m-deep hole at average rates of 6–20 cm.. We demonstrate that pore fluid processes can explain both the triggering of the tensile fracture swarms and their slow migration rates. Our results indicate that the tip of fractures propagating away from the borehole maintained near-critical states over time such that relatively small increases in fluid pressure triggered tensile fracturing episodes, indicating that carbon sequestration efforts in mafic rocks should be able to open fractures and expose fresh rock to mineralization.
{"title":"Slowly Migrating Fracture Swarms in an Actively Serpentinizing Borehole","authors":"John M. Aiken, Fabian Barras, François Renard, Greg Hirth, Peter B. Kelemen, Robert A. Sohn","doi":"10.1029/2025JB032133","DOIUrl":"10.1029/2025JB032133","url":null,"abstract":"<p>Peridotite rocks are primary targets for engineered geological carbon sequestration efforts because the carbon in <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mtext>CO</mtext>\u0000 <mn>2</mn>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${text{CO}}_{2}$</annotation>\u0000 </semantics></math>-bearing fluids is transferred to the rock in the form of carbonate minerals during alteration reactions. Sequestration efforts must necessarily open fractures in the rocks surrounding a pumped borehole, but the current understanding of fracture growth during serpentinization of peridotite is limited to theoretical models and laboratory experiments on small samples. We deployed hydrophone arrays in peridotite boreholes established by the Oman Drilling Program and detected downward migrating fracture swarms that represent the first field observations of fracture growth in a serpentinizing rock. More than 2 years after the boreholes were established, we detected four, downward migrating tensile fracture swarms during an interval of elevated pore pressure following large rain events. All of the swarms occurred within a partially confined section of the local aquifer, beginning at a depth of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>170 m and migrating to the bottom of the 400 m-deep hole at average rates of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>6–20 cm.<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>s</mi>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${mathrm{s}}^{-1}$</annotation>\u0000 </semantics></math>. We demonstrate that pore fluid processes can explain both the triggering of the tensile fracture swarms and their slow migration rates. Our results indicate that the tip of fractures propagating away from the borehole maintained near-critical states over time such that relatively small increases in fluid pressure triggered tensile fracturing episodes, indicating that carbon sequestration efforts in mafic rocks should be able to open fractures and expose fresh rock to mineralization.</p>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":"131 2","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JB032133","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147279453","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}
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