Tectonophysics最新文献

{"title":"Crustal imaging and characterization of active faults with a large-N nodal deployment - Application to the Chaînons Béarnais region (western Pyrenees foothills, France)","authors":"Sébastien Chevrot ,&nbsp;Matthieu Sylvander ,&nbsp;Nicolas Saspiturry ,&nbsp;Amine Ourabah ,&nbsp;Sébastien Benahmed ,&nbsp;Benoît Derode ,&nbsp;Frank Grimaud ,&nbsp;Jean Letort ,&nbsp;Hélène Pauchet ,&nbsp;Guy Sénéchal ,&nbsp;Antonio Villaseñor ,&nbsp;Jean-Baptiste Ammirati","doi":"10.1016/j.tecto.2024.230531","DOIUrl":"10.1016/j.tecto.2024.230531","url":null,"abstract":"<div><div>Understanding the driving forces and nature of intraplate seismicity remains a major unsolved problem in seismology. In the western Pyrénées, seismicity is concentrated in a narrow region that follows the boundary between the Axial Zone and the North Pyrenean Zone. Despite the presence of a permanent network in the region, the geometry of active faults, and their relationship with crustal structures, remain elusive, owing to significant earthquake location uncertainties. Here, we exploit data recorded by a large-N nodal array deployed in the Chaînons Béarnais region during four weeks of 2022 in order to image crustal structures and characterize active faults. We automatically detected and picked P and S waves with PhaseNet, resulting in a catalog of over 500 events, half of which are located beneath the temporary deployment. Tomographic images obtained from the inversion of P and S arrival times provide detailed insight into the geometry of folds and thrusts in the sedimentary cover, as well as the presence of a main fault in the basement which dips northward with an angle of 65° (Chaînons Béarnais normal fault). Seismicity relocation within the 3D model obtained by tomography shows that earthquakes are concentrated along this main active fault, extending from the top of the basement to a depth of approximately 16 km. These results demonstrate that passive imaging approaches can offer cost-effective alternatives to traditional controlled source imaging for seismotectonic studies and natural resource exploration in regions with active seismicity.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"892 ","pages":"Article 230531"},"PeriodicalIF":2.7,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Insight into intracontinental deformation and crustal reworking of ancient continents implied by crustal structure imaging of the Yangtze Craton","authors":"Mingming Jiang ,&nbsp;Tianyu Zheng ,&nbsp;Yumei He","doi":"10.1016/j.tecto.2024.230537","DOIUrl":"10.1016/j.tecto.2024.230537","url":null,"abstract":"<div><div>The crustal imprints from multistage tectonic activities in cratons offer valuable insights into continental evolution. Utilizing seismic data from two densely deployed, nearly perpendicular linear arrays, and a newly developed stepwise joint inversion of depth-domain receiver function and surface wave dispersion, we constructed a detailed crustal layering model for the Yangtze Craton. Our analysis revealed elongated double velocity reversal zones as salient features of the crust, which likely record ancient crustal reworking and juvenile crustal growth associated with Neoproterozoic rift-related magmatic processes. The interlayering of low- and high-velocity structures may contribute to the enduring stability of the Yangtze Craton. Additionally, superimposed layers separated by east-dipping interfaces and abrupt changes in crustal thickness in the boundary belts surrounding the Yangtze Craton document the crust's structural responses to intracontinental deformation during continent assembly.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"892 ","pages":"Article 230537"},"PeriodicalIF":2.7,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552845","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":"Structural evolution of the Horoman peridotite complex in conjunction with the formation of the Hidaka Metamorphic Belt, Hokkaido","authors":"Kazuki Matsuyama ,&nbsp;Katsuyoshi Michibayashi","doi":"10.1016/j.tecto.2024.230535","DOIUrl":"10.1016/j.tecto.2024.230535","url":null,"abstract":"<div><div>We conducted crystal-fabric analyses of peridotites within the Horoman peridotite complex in the Hidaka metamorphic belt, Hokkaido, Japan. Over fifty oriented peridotite samples were collected and analyzed for olivine fabric strength (<em>J</em>-index) and crystallographic preferred orientations (CPOs). The peridotites contained four olivine CPOs: A, E, D, and AG types. We confirmed that olivine CPOs presented a transitional distribution from E to A to AG type from south to north. Previous experimental studies have demonstrated that E type CPO can merge under hydrous conditions. In addition, magnetotelluric observations suggested that the subducting oceanic plate supplies pore fluid to the basal thrust in the region (the Hidaka Main Thrust). Therefore, we infer that the E type CPO was originated from a local water infiltration event. AG type CPO, on the other hand, was considered as a secondary product enhanced by the synkinematic melts in the northern (geological upper) part, combined with the pressure-temperature path inferred by previous petrological studies. Furthermore, we reconstructed the senses of shear strain using the microstructure and olivine crystal-fabrics. Then we built the tectonic history of the Horoman peridotite complex integrating the structural development of the Hidaka metamorphic belt.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"892 ","pages":"Article 230535"},"PeriodicalIF":2.7,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"New insight into the velocity and anisotropy structures of the subduction zone in northern Sumatra","authors":"Xueyuan Huang ,&nbsp;Ping Tong","doi":"10.1016/j.tecto.2024.230534","DOIUrl":"10.1016/j.tecto.2024.230534","url":null,"abstract":"<div><div>In this study, we conducted seismic tomographic inversions to investigate the velocity and anisotropy structures of northern Sumatra, using 9774 P-wave and 8405 S-wave arrivals from regional earthquakes. Isotropic P-wave velocity, isotropic S-wave velocity, P-wave azimuthal anisotropy, and P-wave radial anisotropy models were generated using eikonal equation-based traveltime tomography methods. The study identified low-velocity zones beneath the Toba and Sinabung volcanoes, potentially indicating the presence of magma reservoirs. Furthermore, low-velocity anomalies above the subduction slab were detected, which were likely caused by the dehydration of the slab and interpreted as channels of upwelling flow. The tomographic results revealed a trench-parallel high-velocity belt in the uppermost mantle, representing the subducting slab of the India-Australian plate. The trench-parallel fast velocity directions in the slab suggested that the subducted oceanic slab retains its frozen-in anisotropy formed at the mid-ocean ridge, or that the anisotropy is induced by the lattice-preferred orientation of the B-type olivine. Negative radial anisotropy in the mantle wedge was observed, reflecting hot upwelling flows and transitions of olivine fabrics in the presence of water due to slab dehydration. The results also indicated a multilevel magma plumbing system beneath the Toba Caldera. In summary, the results of this study provided new insights into the structure and dynamic processes of the northern Sumatra subduction zone.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"892 ","pages":"Article 230534"},"PeriodicalIF":2.7,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552850","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":"Deep plutonic bodies over low-frequency earthquakes revealed from receiver-side Green's functions","authors":"Yasunori Sawaki ,&nbsp;Yoshihiro Ito ,&nbsp;Emmanuel Soliman M. Garcia ,&nbsp;Ayumu Miyakawa ,&nbsp;Takuo Shibutani","doi":"10.1016/j.tecto.2024.230536","DOIUrl":"10.1016/j.tecto.2024.230536","url":null,"abstract":"<div><div>Seismological heterogeneity in subduction zones provides insights into slow earthquakes and potential megathrust earthquakes. Studies at the Kii Peninsula in the Nankai subduction zone suggest that there are high-density and high-velocity plutonic bodies in the accretionary prism over the subducting slab, potentially influencing megathrust earthquakes. The lateral variation of heterogeneity and the spatial extent of plutonic bodies remain to be investigated well. Our passive-source imaging of receiver-side Green's functions, from widely distributed campaign seismic observations, reveals a sharp negative S-wave velocity contrast on the top surface of the subducting Philippine Sea plate common to all along-dip profiles and a positive phase tilted upward in the forearc crust. The low permeability of the forearc crust prevents the infiltration of slab-dehydrated fluid further into the upper crust. In the western area, we also found positive phases tilted upward in the forearc crust. The negative phase extends towards the deeper extent of slow-earthquake sources. Meanwhile, the positive phase likely represents the top surface of plutonic rocks of the Kumano and Ohmine plutons that span all the way down to the plate interface. Together with observations of gravity anomaly, intraslab seismicity, and seismic tomography, our interpretation supports the presence of plutonic bodies which extend deep beneath the forearc crust as well as laterally over the subducting PHS slab, rather than a serpentinized mantle wedge. The upper plate is generally low in permeability, but areas with localized high permeability may exist on the updip side of tremor sources. This condition, wherein fluid can infiltrate upwards locally, may maintain the relatively less active slow earthquakes in the western area. The lateral variation of the upper-plate lithology likely influences fluid processes and slow earthquake activities.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"892 ","pages":"Article 230536"},"PeriodicalIF":2.7,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Rupture behaviors of the southern Xianshuihe fault and seismicity around Mt. Gongga: Insights from the 2022 MW 6.6 Luding (China) earthquake sequence","authors":"Wenzheng Gong ,&nbsp;Lingling Ye ,&nbsp;Shiqing Xu ,&nbsp;Yipei Tan ,&nbsp;Xiaofei Chen","doi":"10.1016/j.tecto.2024.230538","DOIUrl":"10.1016/j.tecto.2024.230538","url":null,"abstract":"<div><div>The 2022 <em>M</em>_<em>W</em> 6.6 Luding earthquake occurred on the Moxi segment of the Xianshuihe fault at the southeast margin of Tibetan Plateau, China. To assess the seismic potential of the Moxi segment, we examine the rupture process of the mainshock and aftershock sequence, along with historical seismicity. Our preferred slip model inverted from teleseismic body waves and regional GNSS static displacements shows a dominant southeastward rupture consisting of two distinct, prominent slip patches along strike extending by ∼15 km, with a peak slip of ∼2.8 m, approximately balancing the slip deficit since the last major earthquake in 1786. The northern section of the Moxi segment experienced minor coseismic slip, which, together with the significant slip deficits and positive Coulomb failure stress change induced by the 2022 mainshock indicates a high seismic potential. Several aftershock clusters are distributed along or near the Moxi segment, with strike-slip focal mechanisms around the downdip edge of the coseismic slip area at ∼8‐12 km. At the eastern flank of Mt. Gongga, another cluster of normal faulting aftershocks is located at shallower depths of ∼3‐7 km, with high seismicity rate over ∼9 months including two other M5 sequences in January and February 2023. Similar intense shallow normal faulting activity had occurred after the impoundment of the nearby Dagangshan reservoir in 2015. We speculate that some NW-SE trending normal faults were initially developed by the gravitational collapse of Mt. Gongga underneath the eastern flank, further weakened by fluid flow, as supported by the existence of hot springs and water impoundment, and reactivated by the tensional stress change induced by the 2022 mainshock. These results have important implications for assessing the seismic hazard in and around the Moxi segment, and the potential interplay between strike-slip fault and nearby mountain areas.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"892 ","pages":"Article 230538"},"PeriodicalIF":2.7,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552849","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":"Fault strength, healing and stability in the Nankai Trough accretionary prism off Kii Peninsula, Japan, as illustrated by friction experiments on gouge of a cored sample","authors":"Kyuichi Kanagawa,&nbsp;Junya Fujimori ,&nbsp;Tomoya Nakanishi ,&nbsp;Sayumi Sagano ,&nbsp;Michiyo Sawai","doi":"10.1016/j.tecto.2024.230526","DOIUrl":"10.1016/j.tecto.2024.230526","url":null,"abstract":"<div><div>In order to investigate fault strength, healing and stability in the Nankai Trough accretionary prism off Kii Peninsula, Japan, we conducted two series of triaxial friction experiments on gouge of a silty-claystone sample cored from 2183.6 mbsf (meters below seafloor) at IODP Site C0002, at confining pressure (<em>P</em>_c), pore-water pressure (<span><math><msub><mi>P</mi><mrow><msub><mi>H</mi><mn>2</mn></msub><mi>O</mi></mrow></msub></math></span>) and temperature (<em>T</em>) conditions simulating those <em>in situ</em> at 1000–6000 mbsf there; rate-stepping tests at axial displacement rates (<em>V</em>_axial) changed stepwise among 0.1, 1 and 10 μm/s, and slide-hold-slide tests at <em>V</em>_axial = 1 μm/s with hold time (<em>t</em>_h) ranging from 10 to 10⁴ s.</div><div>Experimentally determined steady-state and static friction coefficients, <em>μ</em>_ss and <em>μ</em>_s, respectively, and the log-linear <em>t</em>_h dependence of frictional healing, <em>β</em>, exhibit a decrease with simulated depth down to 3000 mbsf at which condition <em>T</em> was 100 °C, followed by an increase toward 6000 mbsf. On the other hand, the rate dependence of <em>μ</em>_ss<em>, a</em> – <em>b</em>, gradually decreases with simulated depth, changing from positive at ≤4000 mbsf through ∼0 at 5000 mbsf to negative at 6000 mbsf at which condition stick slips were observed.</div><div>Our experimental results suggest the presence of a low fault-strength and weak fault-healing zone at ∼3000 mbsf beneath IODP Site C0002, possibly due to elevated pore pressure induced by smectite dehydration. This zone correlates well with the previously reported low seismic-velocity zone and the source area of very low-frequency earthquakes to the south. Our experimental results also suggest that faulting beneath IODP Site C0002 is stable and aseismic at ≤4000 mbsf, transitional at 5000 mbsf, and potentially unstable and seismic at 6000 mbsf. In fact, stick slips corresponding to seismic faulting were observed at the 6000 mbsf condition. This implies that faulting along the plate-boundary thrust located at ∼5200 mbsf beneath IODP Site C0002 is potentially seismogenic.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"893 ","pages":"Article 230526"},"PeriodicalIF":2.7,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142578718","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":"Tectonics of the Mw 6.8 Al Haouz earthquake (Morocco) reveals minor role of asthenospheric upwelling","authors":"Marco G. Malusà ,&nbsp;Alessandro Ellero ,&nbsp;Giuseppe Ottria","doi":"10.1016/j.tecto.2024.230533","DOIUrl":"10.1016/j.tecto.2024.230533","url":null,"abstract":"<div><div>A reliable identification of the fault responsible for the magnitude 6.8 Al Haouz earthquake that struck Morocco on 8 September 2023 has so far been hampered by a lack of accurate tectonic analyses. Here we provide the first updated tectonic framework of the earthquake epicentral area based on original field data. We cast our results into the context of available geomorphological, thermochronological and geophysical constraints, and discuss the earthquake characteristics within the framework of competing tectonic models either based on asthenospheric upwelling or transpressional tectonics. We found that the Al Haouz earthquake was likely generated by rupture along a north-dipping high-angle fault, linking former fault planes belonging to an orogen-scale WSW-ESE transpressional shear zone. The geological evolution and seismotectonic structure of the region are largely governed by the oblique convergence of tectonic plates. The impact of asthenospheric upwelling, if any, remains limited and may only influence the geomorphological evolution of the Western High Atlas, but cannot explain the seismotectonic and geological features observed today at the surface, which are instead effects of transpressional tectonics.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"891 ","pages":"Article 230533"},"PeriodicalIF":2.7,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142442748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Shale gas leakage and fault activation: Insight from the 2021 Luxian MS 6.0 earthquake, China","authors":"Zhaofei Liu ,&nbsp;Zhi Chen ,&nbsp;Ying Li ,&nbsp;Zhidan Zhao ,&nbsp;Shunying Hong ,&nbsp;Le Hu ,&nbsp;Ling Ma ,&nbsp;Chang Lu ,&nbsp;Yuanxin Zhao ,&nbsp;Hongyi He ,&nbsp;Shujuan Su ,&nbsp;Ying Zhao ,&nbsp;Weiye Shao ,&nbsp;Zhengyang Cao ,&nbsp;Hanyu Wang","doi":"10.1016/j.tecto.2024.230530","DOIUrl":"10.1016/j.tecto.2024.230530","url":null,"abstract":"<div><div>In the region of large gas fields, extensive research has been conducted on earthquakes induced by industrial production in shale gas fields. However, limited attention has been given to the impact of post-earthquake events on shale gas reservoir leakage and fault activation. The Luxian <em>M</em>_S 6.0 earthquake, which occurred on 16 September 2021 in the Luzhou shale gas field, has raised concerns about post-earthquake shale gas leakage. Post-earthquake measurements of soil gases (Rn, CO₂, CH₄, and H₂) and isotopic analyses (δ¹³C_CO2, δ¹³C_CH4 and δD_CH4) in the Luzhou shale gas field area reveal that the Huayingshan fault zone, a natural pathway for shale gas leakage, was not activated by the Luxian earthquake and did not exhibit any further shale gas leakage after the 2021 earthquake. Furthermore, the seismogenic fault, which was impacted by the earthquake, did not damage the shale gas reservoir, causing shale gas leakage. This study provides an important foundation for future research on shale gas extraction and seismic activity in the region.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"891 ","pages":"Article 230530"},"PeriodicalIF":2.7,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142438156","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":"A numerical study of contemporary crustal deformation partitioning across the Southwestern Tian Shan orogen","authors":"Weilin Kong ,&nbsp;Luyuan Huang ,&nbsp;Yebo Li ,&nbsp;Yiwei Tian","doi":"10.1016/j.tecto.2024.230529","DOIUrl":"10.1016/j.tecto.2024.230529","url":null,"abstract":"<div><div>The Tian Shan region is a typical example of crustal deformation within an intracontinental environment, where the lithospheric rheological properties are marked by significant spatial heterogeneity. However, the role of lithospheric rheology in crustal strain partitioning within the interior of the Tian Shan orogenic belt remains nebulous. Here, we utilized a two-dimensional viscoplastic model with contact elements constrained by GPS velocities and fault slip rates to investigate the influence of the block's strength on crustal deformation in the southwestern Tian Shan region. Our founding suggests that a weaker lower crust beneath the northern Tian Shan region offers a potential mechanism for the contemporary deformation patterns. Contemporary crustal deformation at Tian Shan is mainly concentrated along the piedmont thrust-and-fold belts and diffuses in the orogen's interior. This pattern of crustal strain partitioning is closely linked to the interplay between fault slips and lithospheric deformation. This finding emphasizes the significant role that the lithospheric rheology and pre-existing faults played in the deformation partitioning in the interior of the Tian Shan orogeny.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"891 ","pages":"Article 230529"},"PeriodicalIF":2.7,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142437925","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}