Journal of Structural Geology最新文献

{"title":"High-resolution geological studies of seismogenic structures","authors":"Zhikun Ren ,&nbsp;Olaf Zielke ,&nbsp;J. Bruce H. Shyu ,&nbsp;Richard Walker","doi":"10.1016/j.jsg.2024.105306","DOIUrl":"10.1016/j.jsg.2024.105306","url":null,"abstract":"<div><div>Strong earthquakes rank among the most devastating natural disasters, with the potential to inflict catastrophic damage on communities and critical infrastructure worldwide. The structural geological and geophysical study of seismogenic features remains a cornerstone of earthquake research, providing essential insights into the dynamic processes driving these powerful events. High-resolution investigations in geomorphology, stratigraphy, and structural geology allow for a detailed understanding of the spatial and temporal characteristics of seismic deformations, encompassing co-seismic, post-seismic, and inter-seismic stages, potentially spanning multiple earthquake cycles. The integration of cutting-edge techniques—such as high-resolution data from Light Detection and Ranging (LiDAR), Structure from Motion (SfM), geophysical surveys, drilling, and frictional laboratory experiments—coupled with precise dating methods, enables quantitative analysis at high spatial resolutions across diverse temporal ranges, from years to millions of years. Recent advancements in frictional experimental techniques and numerical modeling have also significantly refined our understanding of deformation processes within seismogenic structures. This special issue compiles research on tectonic activities related to seismogenic structures from varied global tectonic setting, with a focus on leveraging high-resolution spatial data and sophisticated dating techniques. The contributions aim to deepen our understanding of the dynamics underlying strong earthquakes and improve our capacity for seismic hazard assessment.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"191 ","pages":"Article 105306"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143150877","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}

{"title":"Microstructures along volcanic avalanche fault zone in French Massif Central","authors":"Karine Bernard","doi":"10.1016/j.jsg.2024.105327","DOIUrl":"10.1016/j.jsg.2024.105327","url":null,"abstract":"<div><div>Microscale structures are rarely studied along volcanic avalanche fault zones. Here, the well-exposed basal contacts of the Perrier avalanche units are described in the French Massif Central, which exhibit various deformed sedimentary structures, including planar sheared contacts, asymmetric undulations, schistose bands within a sandy matrix, sigmoids, shears bounding subangular clasts, and cataclastic shear bands.</div><div>The occurrence of a breaking force chain along clastic veins, antithetic rotational shear, and clastic disaggregation characterize sequential microfabrics. The quartz microstructures observed along the basement of the volcanic avalanche units indicate a combination of syn and post-seismic creep in the low temperature plasticity regime. The microstructural evolution of mica fish records deformation accommodated at variable pressure and thermal conditions along clastic shear bands. Granular segregations with interclastic pumice matrices and cataclastic matrix transformations are related to co-seismic fluids. This volcanic avalanche fault zone has experienced a vertical and lateral gradient of sequential deformations related to lateral spreading in a rift zone that contained a topographic obstacle.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"191 ","pages":"Article 105327"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143150880","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}

{"title":"3D structural implicit modelling of folded metamorphic units at Lago di Cignana with uncertainty assessment","authors":"Gloria Arienti ,&nbsp;Andrea Bistacchi ,&nbsp;Guillaume Caumon ,&nbsp;Bruno Monopoli ,&nbsp;Giovanni Dal Piaz","doi":"10.1016/j.jsg.2024.105329","DOIUrl":"10.1016/j.jsg.2024.105329","url":null,"abstract":"<div><div>We present a modelling workflow for the creation of a km-scale, three-dimensional representation of the tectonic architecture exposed in the Lago di Cignana region within the Italian Pennine Alps. The model portrays notable tectonic boundaries such as the Dent Blanche Basal Thrust, the Combin Fault and the Roisan-Cignana Shear Zone. Our approach employs the implicit Discrete Smooth Interpolator, which represents the tectonic sequence as a volumetric scalar field generalising a relative distance function. The interpolation process is constrained by geological and structural field data. To model folds that outcrop in the region, we perform three-dimensional interpolation of fold axes, and we enforce these interpolated directions on the fold geometries through tangent constraints complementing the regularisation term in the least-squares system. Furthermore, we address structural uncertainty on isoclinal recumbent folds exposed in the area by simulating a collection of virtual data at randomly located outcrops and stochastically simulating fold axes away from direct observations. These simulated fold axes are arranged in spherical orientation distributions consistent with field data and are used as additional constraints for implicit interpolation. The uncertainty analysis generates multiple scenarios for non-cylindrical folds in terms of axis orientations and interlimb angle.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"191 ","pages":"Article 105329"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143150906","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}

{"title":"Rift structure and development: The Krafla Fissure Swarm (Northern Iceland)","authors":"Martina Pedicini ,&nbsp;Fabio Luca Bonali ,&nbsp;Noemi Corti ,&nbsp;Alessandro Tibaldi","doi":"10.1016/j.jsg.2024.105332","DOIUrl":"10.1016/j.jsg.2024.105332","url":null,"abstract":"<div><div>Understanding rift evolution is important for seismic and volcanic hazard assessment, as highlighted by recent dyking events in Iceland. We analysed 2507 structures constituting the N-S Krafla Fissure Swarm (KFS) through the ArcticDEM, 12 original orthomosaics, derived from historical aerial photos, and field reconnaissance. At a scale of 1:50,000, we identified and studied 323 eruptive fissures, 1412 extension fractures, 759 normal faults, and 13 caldera rim faults. Structures show a decrease in intensity northward and southward from the Krafla Caldera. Fault slip profiles are predominantly asymmetric, showing cumulative offsets tapering outward from the caldera. Fault slip rates, measured along normal faults cutting post-LGM units, range from 0.06 to 6.55 mm/yr, and decrease outward from the Krafla Caldera. These patterns resulted from repeated dykes propagating laterally from the Krafla magma chamber along the rift, a gradual deepening of the dyke tip, and a lower occurrence and thinning of dykes with distance. An along-rift asymmetry is given by more abundant extension fractures in the northern portion of the KFS and more normal faults in its southern part, together with a decrease in rift width from an average of 7.5 km in the south to 6 km in the north, and a decrease of dilation values, from 32.5 m to 14 m in the same direction. The KFS is subject to a double process of rift development given by the local effect of dykes protruding from the Krafla magma chamber, and the regional stress field determining a general northward development of the rifts in northern Iceland.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"191 ","pages":"Article 105332"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143150910","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}

{"title":"Data sampling strategies for accurate fault analyses: A scale-independent test based on a machine learning approach","authors":"Tiago M. Alves ,&nbsp;Joshua Taylor ,&nbsp;Padraig Corcorant ,&nbsp;Ze Tao","doi":"10.1016/j.jsg.2025.105342","DOIUrl":"10.1016/j.jsg.2025.105342","url":null,"abstract":"<div><div>Seismic and outcrop data from SE Brazil, Greece and SW England are used to develop a new method to correctly identify tectonic fault segments – either active or quiescent - using a machine learning approach. Three-dimensional (3D) analyses of tectonic faults are often based on the mapping of throw values (T) along their full length (D) or depth (Z) using a wide range of data. Yet, the collection of these throw values using geophysical or outcrop data is often time-consuming and onerous. In contrast to many empirical measurements of T/D and T/Z, our new method supports the mapping of active (or potentially active) fault segments and limits data undersampling, a caveat that results in the grouping of faults as single zones, systematically overlooking their natural segmentation. The new method is scale-independent and resulted in the definition of a minimum sampling ratio necessary for accurate fault segment mapping. Determined through the gradual downsampling of T/D and T/Z data to a critical point of information loss, the minimum sampling interval (δ) in T/D and T/Z data, expressed as a percentage of fault length, or height, is: a) <span><math><mrow><mn>1.02</mn><mo>%</mo><mo>±</mo><mn>0.02</mn></mrow></math></span> for faults that are longer or higher than 3.5 km; b) <span><math><mrow><mn>4.167</mn><mo>%</mo><mo>±</mo><mn>0.18</mn></mrow></math></span> for isolated faults that are shorter than 3.5 km in either length or height. This work is therefore important as it shows that one should never acquire T/D and T/Z data above a threshold <span><math><mrow><mi>δ</mi></mrow></math></span> value of 4% to identify successive, linked fault segments, whatever their scale. Total accuracy in fault-segment detection is only assured for δ values of 1% when in the presence of fault zones with segments longer than 3.5 km. As a corollary, we confirm that T/D and T/Z data are often undersampled in the published literature, leading to a significant bias of subsequent interpretations towards coherent constant-length growth models when analyzing both active and old, quiescent fault systems.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"191 ","pages":"Article 105342"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143151532","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}

{"title":"Did along-strike changes in continental subduction styles occur in the Dabie-Sulu orogenic belt?","authors":"Ruirui Wang ,&nbsp;Zhong-Hai Li ,&nbsp;Qihua Cui ,&nbsp;Zhiqin Xu","doi":"10.1016/j.jsg.2024.105321","DOIUrl":"10.1016/j.jsg.2024.105321","url":null,"abstract":"<div><div>The Triassic collision between the North China Block (NCB) and the South China Block (SCB) formed the Dabie-Sulu orogenic belt, renowned for its extensive ultra-high-pressure metamorphic rocks and the prominent Tan-Lu Fault. Geological and geophysical data reveal significant along-strike differences in both shallow and deep structures within the belt, raising a critical question: What tectonic processes drive these structural variations? Considering that the Triassic collision involved pre-collisional accreted microcontinents and along-strike variations in convergence velocities, this study investigates the influence of microcontinental width, convergence rate, and initial Moho temperature on continental subduction styles using numerical modeling. The models incorporate pre-collisional accreted microcontinent(s) and reveal a two-stage subduction evolution: an initial transition from one-sided to two-sided continental subduction, followed by subduction polarity reversal. High initial Moho temperatures, rapid convergence rates, and wide accreted microcontinents promote the development of two-sided subduction, characterized by an initially vertical interface that gradually inclines towards the pro-plate as convergence progresses. These subduction styles significantly influence crustal suture migration. One-sided subduction results in minimal horizontal displacement, whereas two-sided subduction and polarity reversal lead to substantial horizontal shifts. Based on the modeling results, this study proposes a new evolutionary model for the Dabie-Sulu orogenic belt during the NCB-SCB collision. The model effectively explains along-strike structural differences, such as the inconsistent tectonic trends on either side of the Tan-Lu Fault and the opposite dipping directions of high-velocity mantle anomalies observed in geophysical profiles. Furthermore, the proposed model sheds light on the formation and evolution of the Tan-Lu Fault.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"191 ","pages":"Article 105321"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143151594","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}

{"title":"Erratum to “Did along-strike changes in continental subduction styles occur in the Dabie-Sulu orogenic belt?” [Journal of Structural Geology 191 (2025) 105321]","authors":"Ruirui Wang ,&nbsp;Zhong-Hai Li ,&nbsp;Qihua Cui ,&nbsp;Zhiqin Xu","doi":"10.1016/j.jsg.2024.105335","DOIUrl":"10.1016/j.jsg.2024.105335","url":null,"abstract":"","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"191 ","pages":"Article 105335"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143378970","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}

{"title":"Facies and mechanical stratigraphy control fracture intensity, topology and fractal dimension in folded turbidite sandstones, Northern Apennines, Italy","authors":"A. Lucca ,&nbsp;F. Balsamo ,&nbsp;C.A. De Risio ,&nbsp;K. Ogata ,&nbsp;F. Porta ,&nbsp;S. Tavani ,&nbsp;F. Storti","doi":"10.1016/j.jsg.2024.105307","DOIUrl":"10.1016/j.jsg.2024.105307","url":null,"abstract":"<div><div>Fracture network intensity, topology and connectivity have been frequently analysed using circular scan windows, an efficient method for geometrical properties characterization, although affected by truncation and censoring. Many studies that use circular scans focus on the spatial variation of the geometrical properties in relation to tectonic structures such as faults and folds, and at the regional scale. A lower amount of information is available in the literature on the relations between depositional features, mechanical and petrophysical properties of facies, and the corresponding fracture network geometrical attributes. In this contribution, we focus on these relationships, which are fundamental controlling factors for predicting fracture geometry in the subsurface and for improving modelling in exploration, production and management of reservoirs for fluid exploitation and storage. We characterized these properties in 35 selected turbidite beds of the Marnoso-arenacea Fm., in the Northern Apennines of Italy, exposed along a 250 m-thick section. Moreover, we calculate the fractal dimensions of fracture networks through the box-counting method. Our data indicate that depositional facies control porosity and uniaxial compressive strength, as well as fracture intensity and fracture network topology. We show that fracture intensity is invariant and unrelated to the sandstone facies thickness in medium-grained turbidite beds. On the other hand, a strong control on fracture intensity in fine-grained turbidite beds is also exerted by the thickness of bounding claystone, which is higher when the bounding claystone is thicker. Moreover, we observe that the cross joint pattern and strike could be influenced by the depositional structures.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"191 ","pages":"Article 105307"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143150879","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}

{"title":"Intrarift fault interactions: Insights from coseismic stress redistribution from large seismogenic segment ruptures, Northern Malawi Rift","authors":"Emmanuel A. Njinju ,&nbsp;Folarin Kolawole ,&nbsp;D. Sarah Stamps ,&nbsp;Estella A. Atekwana ,&nbsp;Franck Eitel Kemgang Ghomsi ,&nbsp;Eliot A. Atekwana","doi":"10.1016/j.jsg.2024.105326","DOIUrl":"10.1016/j.jsg.2024.105326","url":null,"abstract":"<div><div>The understanding of the factors influencing the active interaction and coalescence of intrarift fault segments in extending continental regions is limited. The 2009 Mw6.0 Karonga earthquake occurred in the westernmost portion of the Northern Malawi Rift, which hosts clustered intrarift faulting. The event ruptured the strongly coalesced southern segment of the St. Mary Fault (sSMF), and subsequently, moderate-magnitude events localized on poorly -coalesced segments that define the northern continuation of the fault. To investigate the role of coseismic stress redistribution on interacting faults, we explore the slip distribution of the 2009 event with realistic 3D strike-variable fault geometries, and compute coseismic Coulomb stress changes around the sSMF and neighboring faults. The results suggest that the down-dip intersections of the sSMF with the neighboring faults partition strain in a way that directs most of the deformation to &gt;5 km depths. Additionally, the coseismic stress changes from the 2009 earthquake promoted interactions between the sSMF and adjoining northern segments of the fault at shallow (&lt;5 km) depths, indicating that upper-crustal hard-linkage is underway in the poorly coalesced en-echelon sections of the northern segment. These results demonstrate how coseismic static stress transfer between evolving intrarift fault systems drive fault linkage over a single seismic cycle. Over successive slip events, such stress transfer processes may accelerate the linkage and coalescence of contiguous intrarift fault segments, amalgamate and deepen sub-basins along-strike, and promote across-rift basin compartmentalization. This process is relevant for fault coalescence over multi-seismic cycles, progressive maturation of rift basins, and transitions from juvenile continental rifting to the development of margins where break-up can initialize.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"191 ","pages":"Article 105326"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143150905","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}

{"title":"Thrust vs. fold nappes: Mechanical and geometrical controls from 2D numerical simulations and applications to a recumbent fold of the Pyrenees","authors":"Marc Guardia ,&nbsp;Albert Griera ,&nbsp;Boris J.P. Kaus ,&nbsp;Andrea Piccolo ,&nbsp;Norbert Caldera ,&nbsp;Antonio Teixell","doi":"10.1016/j.jsg.2024.105314","DOIUrl":"10.1016/j.jsg.2024.105314","url":null,"abstract":"<div><div>Thrust and fold nappes are found in the internal and external portion of orogenetic belts, and have been the subject of geometric and kinematic characterization during the last century. In spite the extensive studies, there is still not a full understanding of the processes and properties that favour thrusting over folding and vice versa. We address this issue by numerical modelling with application to a natural case of the Pyrenees, the Eaux-Chaudes massif, an Alpine fold-and-thrust structure in the western Axial Zone. The Eaux-Chaudes structure consists of a basement-cored recumbent fold nappe with a large reverse limb in ductilely-deformed Upper Cretaceous carbonates, transitioning laterally to the east to an imbricate thrust fan that also exhibits ductile deformation to the east. The spatio-temporal association of these structural styles at Eaux-Chaudes can be a consequence of the pre-orogenic configuration and highlights the need to investigate under which conditions and precursor geometries one or the other nappe style are favoured. Here, we present a systematic numerical modelling study of the variability in the initial mechanical and geometrical conditions, using the thermomechanical staggered finite-difference code LaMEM. We also investigate the mechanism that favour the potential migration of fold hinges and lead to the preservation of layer thickness in the reverse fold limbs, and quantify it with a new nondimensional parameter, the localisation index (<em>I</em>_<em>loc</em>).</div><div>Our results demonstrate the need of a stiff forestop for nappe development. The absence of a forestop causes detachment buckle folds in the strong layers. Deep burial and the combination of a thick upper decoupling unit and a lower detachment level are essential features favouring viscous behaviour and spatially distributed deformation, enabling recumbent folding by progressive hinge migration, and characterized by low and stable values of <em>I</em>_<em>loc</em>. On the other hand, shallower conditions, short lengths of the stiff layer and lower friction angles inhibit hinge migration. Instead, they enhance instead reverse limb stretching and shearing, which eventually results in strain localisation and thrusting. These are characterized by a moderate-to-quick rises of <em>I</em>_<em>loc</em>. Our results may be applicable to other orogenic belts and to other parts of the Axial Pyrenean hinterland where the Mesozoic cover has been eroded and the Alpine deformation is obscure.</div></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":"191 ","pages":"Article 105314"},"PeriodicalIF":2.6,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143150908","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}