Tectonophysics最新文献

{"title":"Analysis of the Dawanqi salt anticline in the Kuqa fold-and-thrust belt and implications for the growth of compressional salt anticlines","authors":"Wanhui He ,&nbsp;Wei Wang ,&nbsp;Chao Wu ,&nbsp;Tao Mo ,&nbsp;Weili Chen ,&nbsp;Hongwei Yin ,&nbsp;Zihan Gao","doi":"10.1016/j.tecto.2025.230919","DOIUrl":"10.1016/j.tecto.2025.230919","url":null,"abstract":"<div><div>Well-preserved salt structures in the Kuqa fold-and-thrust belt provide an ideal opportunity to quantitatively study the evolution of compressional salt anticlines. The Dawanqi salt anticline in the northwestern part of the Kuqa fold-and-thrust belt is closely associated with hydrocarbon accumulation. Its structural evolution plays a key role in controlling the timing and distribution of sub-salt faults and reservoirs. Sequential restoration is an effective method for revealing the structural evolution of the Dawanqi salt anticline. In this study, we constructed a 3D model of the structural evolution of the Dawanqi salt anticline and undertook sequential restoration and a quantitative analysis of the morphological changes. The results show that the Dawanqi salt anticline evolved in three stages: slow growth during the Miocene, rapid growth and lateral widening of the salt dome, and significant foreland-ward migration during the early Pliocene, followed by vertical uplift at a fixed location during the late Pliocene. If the regional compressive stress remains unchanged or increases in magnitude over time, the structure may eventually breach the surface and evolve into a salt diapir. We obtained a strong positive correlation between the shortening rate and vertical growth rate of the anticline, while hinge migration is highly sensitive to the thickness of the overlying load. We propose an alternative piercement model for the potential future evolution of the salt anticline, in which sustained vertical growth under compressional stress drives the transition from salt anticline to diapir. This model presents a distinctive halokinetic growth-strata pattern compared with previous models and complements existing thrust and erosional piercement models proposed for compressional settings.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"914 ","pages":"Article 230919"},"PeriodicalIF":2.6,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145061056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simulation of large earthquake synchronization and implications on North Anatolian fault zone","authors":"E. Sopacı ,&nbsp;A.A. Özacar","doi":"10.1016/j.tecto.2025.230902","DOIUrl":"10.1016/j.tecto.2025.230902","url":null,"abstract":"<div><div>The North Anatolian Fault (NAF) zone has consistently exhibited a sequence of westward-migrating earthquakes with magnitudes exceeding 7 (<span><math><mrow><msub><mrow><mi>M</mi></mrow><mrow><mi>w</mi></mrow></msub><mo>&gt;</mo><mn>7</mn></mrow></math></span>) during its last three seismic cycles. To investigate the mechanisms underlying this behavior, we conducted multi-cycle simulations using a rate-and-state friction (RSF) model. The model incorporates three seismogenic asperities aligned along the fault strike, separated by barriers that inhibit rupture propagation. By simulating spontaneously occurring earthquakes, we analyzed variations in the timing of large events across the asperities. Our results indicate that both the strength and length of the barriers play a critical role in controlling the coupling between asperities, while variations in asperity length exert a relatively minor influence. Simulations with very weak barriers—permitting rupture jumps between asperities—and very strong barriers—limiting stress transfer—tended to produce synchronized earthquake cycles. In contrast, intermediate-strength barriers that allowed limited stress transfer generated more variable, non-synchronized cycles. These findings suggest that faults coupled primarily through static stress transfer are more prone to desynchronization, whereas those coupled via dynamic triggering or afterslip may maintain synchronization over multiple cycles. Although the model is simplified, it offers meaningful insights into the seismic behavior of the NAF and contributes to a deeper understanding of fault system dynamics.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"914 ","pages":"Article 230902"},"PeriodicalIF":2.6,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145046089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seismic and aseismic deformation in the Danakil Depression, East Africa and Corinth Rift, Greece: Magma-rich vs magma-poor rift extension","authors":"Gareth L. Hurman ,&nbsp;Derek Keir ,&nbsp;Lisa C. McNeill ,&nbsp;Carolina Pagli ,&nbsp;Jonathan M. Bull ,&nbsp;Georgios Michas","doi":"10.1016/j.tecto.2025.230918","DOIUrl":"10.1016/j.tecto.2025.230918","url":null,"abstract":"<div><div>The mechanisms accommodating extension in magma-rich and magma-poor rifts likely differ, with magmatic intrusion (largely aseismic) potentially dominating magma-rich rifts and faulting (seismic deformation) thought to accommodate most extension in magma-poor rifts. We compared the seismic and aseismic deformation occurring in the Danakil Depression, East Africa (magma-rich) and Corinth Rift, Greece (magma-poor) to test this hypothesis and improve understanding of extension in end-member rifts. The seismic moment release across both rifts was determined using NEIC catalogue earthquake data (from 1950 to 2023). In the Danakil Depression, seismic moment release is highest at the rift margins and sections of the rift axis with reduced magmatism. Seismic moment release is greatest across the eastern part of the Corinth Rift. Regional geodetic extension data were used to calculate the changing geodetic moment rates along both rifts. The ratio between the seismic and geodetic moment rates (S/G) was calculated for the entire rifts and overlapping zones along each rift. The horizontal component of the seismic moment was extracted to calculate the horizontal seismic/geodetic moment rate ratio (S_h/G). The Danakil Depression and Corinth Rift have S/G of 0.03 and 0.43, and S_h/G of 0.02 and 0.28, respectively, suggesting greater amounts of extension being accommodated by faulting in the Corinth Rift. S/G variations along the Danakil Depression are consistent with geological indicators of along-rift variations in faulting. Relatively high S/G (∼0.1) in the north of the Depression indicates that brittle deformation accommodates a significant amount of extension here, despite being potentially in the final stages of magma-rich break-up. Relatively low S/G (∼0.1–0.15) in the west of the Corinth Rift supports the interpretations that aseismic deformation may be significant, potentially on a low-angle detachment at depth. This study confirms our hypothesis that in magma-poor rifts, greater amounts of extension are accommodated by seismic deformation compared with magma-rich rifts.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"915 ","pages":"Article 230918"},"PeriodicalIF":2.6,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145098438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Where does the active North Aegean Sea shear stop? Geodynamic and seismotectonic implications from recent strike-slip earthquake occurrences and GPS-based geodetic analysis in Euboea, Phthiotis and Boeotia, Central Greece","authors":"Sotiris Sboras ,&nbsp;Evangelos Mouzakiotis ,&nbsp;Konstantinos Chousianitis ,&nbsp;Vassilios Karastathis ,&nbsp;Christos P. Evangelidis ,&nbsp;Ilias Lazos ,&nbsp;Antonia Papageorgiou ,&nbsp;Spyros Liakopoulos ,&nbsp;Kyriaki Iordanidou","doi":"10.1016/j.tecto.2025.230917","DOIUrl":"10.1016/j.tecto.2025.230917","url":null,"abstract":"<div><div>Since 2008, eight strike-slip earthquake sequences/swarms have occurred in the broader regions of Boeotia and Euboea, where shear from the North Aegean Sea intersects the extensional province of Central Greece. Notably, the 2023 Elatia sequence unfolded within an area previously considered dominated by pure extension. In broader Euboea, the seismotectonic context has remained ambiguous, with limited implications for the southwestward continuation of North Aegean shear as far as the North Euboean Gulf. We reassessed these sequences/swarms through hypocenter relocation and recalculated moment tensor solutions, integrated with GPS data analysis. Our findings reveal that shear and extension coexist throughout much of the study area, with GPS velocities indicating southeastward increasing movement segmented by four wide and diffuse dextral shear zones. These ‘soft’ boundaries facilitate progressive slip between five compartments, enhancing extension in the North and South Euboean Gulfs. Seismic ruptures of the eight cases occurred on either dextral NE–SW-trending faults or sinistral NW–SE faults, consistent with a ‘wrench’ tectonic model. In this framework, fault patterns correspond to Riedel shears (R) and their conjugates (R′), while the coexisting normal faulting reflects transtensional deformation. The North and South Euboean Gulfs act as rifts, accommodating differential motion between Euboea Island and the mainland. We also conclude that the southwestward propagation of the North Aegean shear zone is a young geodynamic process potentially reaching, at least, the northeastern coast of the Corinth Gulf.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"914 ","pages":"Article 230917"},"PeriodicalIF":2.6,"publicationDate":"2025-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145096213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seismic-constrained gravity inversion of Moho depth beneath Sabah, Malaysia: regional and tectonic implications","authors":"Mazlan Madon ,&nbsp;Harry Linang ,&nbsp;Simone Pilia","doi":"10.1016/j.tecto.2025.230916","DOIUrl":"10.1016/j.tecto.2025.230916","url":null,"abstract":"&lt;div&gt;&lt;div&gt;The geology of Sabah, the eastern Malaysian state in northern Borneo, is complex due to its location in a region of tectonic convergence between Asia, Australia and Pacific plates during the Cenozoic. Current tectonic models suggest that Sabah underwent crustal thickening in a double-subduction system - Oligocene–Early Miocene south-eastward subduction of the Proto-South China Sea beneath NW Sabah and Middle–Late Miocene north-westward subduction of Celebes Sea beneath the Sulu Arc in SE Sabah. In addition, Middle–Late Miocene crustal extension due to back-arc rifting in the Sulu Sea partly shaped the relatively subdued topography of the central-northeast coast of Sabah and the Kinabatangan River basin.&lt;/div&gt;&lt;div&gt;Critical to understanding the complex geology of Sabah is its crustal structure. Previous gravity studies indicate a thickened crust beneath the Crocker Range and adjacent mountainous regions of southern Sabah. More recently, based on receiver function analysis and virtual deep seismic soundings (VDSS) the Moho depth beneath Sabah was determined to be between 21 and 55 km. In this study, Moho depths are estimated by gravity inversion of newly compiled gravity data and calibrated against seismic data derived from VDSS. For input to the gravity inversion, Mantle Bouguer Anomaly (MBA) was derived from free-air anomalies by applying Bouguer and mantle corrections based on topography from SRTM+ digital elevation model. A modified Parker-Oldenberg algorithm was used to invert the Moho depth from the MBA. The gravity inversion requires a mean Moho depth (zo) and a density contrast at the Moho (ρ&lt;sub&gt;c&lt;/sub&gt;) to be set at run-time.&lt;/div&gt;&lt;div&gt;Two models of crustal density were investigated. In Model 1, using a uniform crustal density as input, different combinations of zo and ρ&lt;sub&gt;c&lt;/sub&gt; were tested. The highest correlation between the gravity-derived Moho and the seismic Moho (as calibration points) was attained when the ρ&lt;sub&gt;c&lt;/sub&gt; is unrealistically high (&gt;3000 kg m&lt;sup&gt;−3&lt;/sup&gt;) and, therefore, considered unlikely. In Model 2, we constrained the inversion by applying a laterally-varying crustal density model derived from the VDSS data. With this model, the Moho depth was estimated between 32.8 and 52.5 km, with a mean Moho depth of 40.8 km.&lt;/div&gt;&lt;div&gt;Our analysis indicates that Sabah is not in complete isostatic equilibrium, and parts of the region appear to be highly overcompensated. In particular, across central Sabah a highly thickened crust indicated from gravity contradicts with seismic evidence for a thinner crust. This apparent disparity in Moho depths is the consequence of ignoring two density-related factors in the gravity inversion: (1) the presence of a deep sedimentary basin beneath the upper Kinabatangan River basin, and (2) the thermal effect of a cooling lithosphere beneath the basin, representing the onshore continuation of the SE Sulu Sea rift system. By correcting the input gravity for these effects, the dif","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"914 ","pages":"Article 230916"},"PeriodicalIF":2.6,"publicationDate":"2025-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145027474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical Modeling of Interactions between Shallow and Deep Faults in the North China Plain: Insights from the Sanhe-Pinggu Seismic Zone","authors":"Li Yin ,&nbsp;Bengang Zhou ,&nbsp;Zhengfang Li ,&nbsp;Gang Luo","doi":"10.1016/j.tecto.2025.230906","DOIUrl":"10.1016/j.tecto.2025.230906","url":null,"abstract":"<div><div>Several strong seismic zones in the North China Plain (NCP) share common structural characteristics between deep and shallow seismogenic faults. However, stress interaction or coupling mechanisms between these deep and shallow faults remain unclear. This study examines the Sanhe-Pinggu seismic zone, a representative strong seismic belt in the NCP, using newly acquired data from deep reflection profiles, geological surveys, and geodetic measurements. A 3D viscoelastoplastic finite element model was developed to represent the study area, integrating both deep and shallow seismogenic faults. Through quasi-static geodynamic simulations of stress loading and plastic sliding along pre-existing faults, this model explores the stress-strain evolution of faults under various tectonic loading conditions, revealing the long-term interaction between deep and shallow faults. Results indicate that the stress coupling and interactions between deep and shallow faults are significantly influenced by boundary loading conditions, the depth and presence of detachment layers, and rapid creep along deeper faults. These findings provide critical insights into fault interaction and the mechanism of strong earthquake generation within the NCP.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"914 ","pages":"Article 230906"},"PeriodicalIF":2.6,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145046043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Estimates of S-wave Q(f) in the rupture area of the mainshock and in the last-week foreshocks area preceding the L'Aquila 2009 (Mw6.1) earthquake sequence, Central Italy","authors":"Raúl R. Castro ,&nbsp;Leonardo Colavitti ,&nbsp;Daniele Spallarossa ,&nbsp;Giovanna Calderoni ,&nbsp;Simona Gabrielli ,&nbsp;Francesca Pacor","doi":"10.1016/j.tecto.2025.230907","DOIUrl":"10.1016/j.tecto.2025.230907","url":null,"abstract":"<div><div>We used seismic records from the Central Italy seismic network to estimate the <em>S</em>-wave quality factor <em>Q</em> in the rupture area of the 6 April 2009 L'Aquila (<em>Mw</em> 6.1) mainshock and seven foreshocks with local magnitudes M_L 3.2–4.3 that occurred the week preceding the main event. We separated the attenuation along the source-station path by calculating individual nonparametric spectral attenuation functions for 21 frequencies between 0.20 and 25 Hz for each foreshock and the mainshock. Then, we estimated <em>Q</em> in the rupture zone using the <span><math><msup><mi>ω</mi><mn>2</mn></msup></math></span> source model as a reference. The rate of amplitude decay of the average source-station path attenuation functions is approximately the same for all the events except for two foreshocks located southwest of the main shock. We found that nearby the rupture-zone <em>Q</em> increases with frequency from 0.27 to 30.63 for the mainshock, and from 0.01 to 3.0 for the foreshocks. These low values of near-source <em>Q</em> obtained suggest the likely presence of fluids in the rupture areas of the foreshocks and the mainshock zone of the 2009 L'Aquila seismic sequence.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"914 ","pages":"Article 230907"},"PeriodicalIF":2.6,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145027476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Asthenospheric upwelling-induced seismic activity in the eastern North China Craton: Evidence from viscosity obtained from an MT study","authors":"Baochun Li ,&nbsp;Gaofeng Ye ,&nbsp;Sheng Jin ,&nbsp;Wenbo Wei ,&nbsp;Letian Zhang ,&nbsp;Hao Dong ,&nbsp;Chengliang Xie ,&nbsp;Yaotian Yin ,&nbsp;Shaohuai Sun ,&nbsp;Zhaoyuan Kang ,&nbsp;Peng Ding ,&nbsp;Yiwu Zhang ,&nbsp;Yuanchen Li ,&nbsp;Jien Dong ,&nbsp;Cheng Liu ,&nbsp;Ce Yang ,&nbsp;Haoxiang Yin","doi":"10.1016/j.tecto.2025.230900","DOIUrl":"10.1016/j.tecto.2025.230900","url":null,"abstract":"<div><div>The eastern North China Craton (NCC) suffers from severe seismic hazards. This study investigates the crustal and mantle resistivity structure to constrain the deep tectonic evolution and seismic mechanisms of the eastern NCC. In this paper, the magnetotelluric sounding array deployed in the eastern NCC by the SINOPROBE project was used for data analysis and 3D inversion, and a 3D electrical structure model of the eastern NCC was obtained. The effective viscosity of the lithospheric mantle of the eastern NCC was calculated by combining the Arrhenius equation and the flow law of dislocation creep of wet olivine. The resistivity model shows that the low-resistivity anomalies in the middle and upper crust are mainly distributed in the Bohai Bay Basin. The lithospheres of the Yinshan-Yanshan Block, the Sulu Orogenic Belt, and the Taihang Uplift show high-resistivity anomalies. However, the lithospheric mantles of the Shanxi Graben, the Luxi Uplift, and the southern Taihang Uplift show pronounced low-resistivity anomalies. The low-resistivity anomalies are separated by the high-resistivity lithospheric anomalies in the Yinshan-Yanshan Block and the middle of the Taihang Uplift. The mantle viscosity model calculated using the relationship between conductivity, temperature, and viscosity indicates that the effective viscosity of the lithospheric mantle in the low-resistivity and high-temperature Bohai Bay Basin is lower than that in the high-resistivity and low-temperature Yanshan Block and Taihang Uplift. According to the upwelling shape of the low-resistivity anomalies, the thermal materials beneath Tangshan and Xingtai have the characteristic of upwelling along the tectonic boundaries. It is concluded that after the low-viscosity asthenospheric upwelling to the cold and rigid Yanshan Block and Taihang Uplift, stress accumulates on the side of the high-resistivity anomalies, eventually leading to crustal and mantle seismic activity.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"914 ","pages":"Article 230900"},"PeriodicalIF":2.6,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145027473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Contrasting evolution of upper crustal velocities in young oceanic crust: Insights from the Southern Mid-Atlantic Ridge","authors":"Gail L. Christeson ,&nbsp;William H. Robert ,&nbsp;Rosalind M. Coggon ,&nbsp;John A. Goff ,&nbsp;Aled D. Evans","doi":"10.1016/j.tecto.2025.230905","DOIUrl":"10.1016/j.tecto.2025.230905","url":null,"abstract":"<div><div>Geophysical studies document rapid changes in upper crustal seismic velocities in young ocean crust that are attributed to infilling of cracks as a result of hydrothermal circulation. This study analyzes three seismic reflection profiles located on 0–6 Ma ocean crust on the slow-spreading southern Mid-Atlantic Ridge. Average velocities are ~2.5 km/s at 0 Ma, 3.2 km/s at 0.5 Ma, and 4.0 km/s at 3.5 Ma. Velocities are relatively constant from 3.5 to 6 Myr. Velocity trends are similar along all profiles and on both ridge flanks; this similarity suggests that the underlying processes associated with the velocity changes are widespread. The trends are similar to those observed at the slow-spreading equatorial Mid-Atlantic Ridge. In contrast, velocities at the intermediate-spreading Juan de Fuca Ridge increase more slowly with age than observed at the Mid-Atlantic Ridge. We argue that processes related to spreading rate are a significant factor in the age-related physical property changes. In particular, we highlight that compression associated with stresses related to the axial valley morphology may result in more rapid crack closure on the slow-spreading Mid-Atlantic Ridge than in similar age crust at the intermediate-spreading Juan de Fuca Ridge where axial valley morphology is less pronounced. A secondary control of spreading rate might simply be the increased amount of time slow-spreading crust resides near the ridge axis where the most vigorous hydrothermal circulation occurs. The rate of change of seismic velocity in young crust may be further moderated by the impact of sediment cover on upper crustal alteration.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"914 ","pages":"Article 230905"},"PeriodicalIF":2.6,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145004482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The fine structure and seismogenic mechanism of the Yangjiang intraplate seismic zone in Guangdong Province, South China","authors":"Changrong Zhang,&nbsp;Shaohong Xia,&nbsp;Tao Gou,&nbsp;Chaoyan Fan","doi":"10.1016/j.tecto.2025.230904","DOIUrl":"10.1016/j.tecto.2025.230904","url":null,"abstract":"<div><div>Intraplate earthquakes occur within continental or oceanic plates, characterized by shallow focal depths, potential proximity to densely populated areas, and substantial destructive potential. To date, a scientific consensus of their controlling factors and seismogenic mechanisms remains elusive. Yangjiang, Guangdong, located along the southeastern coast of China, is a typical intraplate shallow-focus seismic zone. This study employed dense seismic array observations to identify and precisely locate seismicity in the Yangjiang region. We performed 3-D P-wave velocity (Vp) tomography using body-wave travel times and conducted joint inversions for S-wave velocity (Vs) structures by integrating body-wave travel times with surface-wave group-velocity dispersions extracted from ambient noise. Additionally, the Poisson's ratio structure was calculated. The results indicate that, except for the Xinhu Reservoir (Zone 1), seismic activity in Yangjiang primarily clusters in the Yangbian Bay (YBB), distributed along the NEE-trending Pinggang Fault. It can be further subdivided into two clusters: the western (Zone 2) and eastern (Zone 3) sectors. Zone 2, located at the intersection of the Pinggang and NW-trending Yangbianhai Faults, exhibits the highest seismicity, notably including a historic Ms6.4 earthquake. Tomographic results show that there are pronounced low Vs and high Poisson's ratio anomalies south of the Pinggang Fault beneath YBB (Zone3), suggesting seawater infiltration through the fault zone. A distinct low Vs and high Poisson's ratio anomaly at 5–13 km depth likely indicates enhanced seawater penetration through the fault intersection, potentially contributing to localized heightened seismicity. Compared to Zone 3, Zone 2 displays higher velocity and lower Poisson's ratio, indicating more rigid lithology that facilitates elastic strain energy accumulation and higher rupture thresholds. It could explain the occurrence of the Ms6.4 earthquake. This study advances the understanding of intraplate earthquake generation mechanisms and provides geophysical constraints for seismic hazard assessment and disaster prevention planning.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"914 ","pages":"Article 230904"},"PeriodicalIF":2.6,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145027475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}