Tectonophysics最新文献

{"title":"Reevaluation of geomorphic offsets along the 1920 Haiyuan earthquake rupture, China: A discussion of uncertainties in slip measurements and COPD analyses using high-resolution topography","authors":"Longfei Han ,&nbsp;Wenqian Yao ,&nbsp;Jing Liu-Zeng ,&nbsp;Yann Klinger ,&nbsp;Chengguo Yan ,&nbsp;Peng Wang ,&nbsp;Yanxiu Shao","doi":"10.1016/j.tecto.2026.231071","DOIUrl":"10.1016/j.tecto.2026.231071","url":null,"abstract":"<div><div>Accurate measurements of coseismic slip distributions derived from geomorphic markers provide essential insights into earthquake rupture dynamics and make a significant contribution to seismic hazard evaluation. With the increased availability of high-resolution topographic data and advanced statistical techniques such as cumulative offset probability distribution (COPD), reconstructing single-event coseismic displacement from cumulative offsets of successive paleoearthquakes has become more feasible. However, assessing the reliability of these methods remains critical. The 1920 <em>M</em>w7.9 Haiyuan earthquake, the most recent major event along the strike-slip Haiyuan fault, serves as an ideal case study due to notable discrepancies in previously reported displacement measurements. In this study, we utilize very high-resolution (0.1 m) topographic data derived from aerial imagery processed via the Structure from Motion (SfM) technique, covering approximately 85 km of the ∼240 km rupture length. Our analysis, based on detailed horizontal slip measurements and COPD calculation, yields a maximum displacement of 7.6 ± 0.8 m for the 1920 Haiyuan earthquake, differing from previous estimates but aligning well with global scaling relationships for strike-slip earthquakes. Our results reveal three COPD peaks in the geomorphic records along the Haiyuan fault. The displacement interval between the two most recent peaks is similar to that of the latest peak, with reduced displacement observed in the western section. These findings suggest that previous interpretations of four to five events may significantly overestimate single-event slip. Comparisons with previous studies underscore the methodological challenges in COPD-based reconstructions, including uncertainties from different slip measurement methods, geomorphic marker interpretations, fault geometry, along-strike slip variability, and the contribution of moderate-magnitude earthquakes to cumulative offsets.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"922 ","pages":"Article 231071"},"PeriodicalIF":2.6,"publicationDate":"2026-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145902931","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":"3D azimuthal anisotropy model reveals crust-mantle deformation in the northeastern Songpan-Ganzi Block and adjacent regions","authors":"Yue Chen ,&nbsp;Qianzong Bao ,&nbsp;Xiaofei Chen","doi":"10.1016/j.tecto.2025.231043","DOIUrl":"10.1016/j.tecto.2025.231043","url":null,"abstract":"<div><div>The northeastern Songpan-Ganzi Block (NE-SPGZ), as the leading edge of the Tibetan Plateau's eastward expansion, remains controversial in its crust-mantle deformation mechanisms. Using teleseismic and ambient noise surface wave dispersion data, we obtained the 3D shear wave velocity and azimuthal anisotropy structure from 5 to 110 km depths. The results show low-velocity anomalies in the upper mantle of the NE-SPGZ and the western Qinling Orogenic Belt (WQL), which may be related to the thermal erosion and localized upwelling of asthenosphere. In the NE-SPGZ, the crust exhibits dominant NW-oriented fast-axis direction consistent with the regional tectonic trend, indicating overall crustal shortening. However, the upper mantle shows NE-oriented fast-axis direction with increased amplitude of anisotropy. We suggest that the combined effect of the asthenospheric activity, northeastward plateau compression, and Sichuan Basin resistance may result in significant NE-directed deformation within the softened upper mantle. The lower crustal low-velocity zone in the NE-SPGZ, generated by felsic crustal deformation, exhibits lateral heterogeneity in its anisotropy. Therefore, we infer that this zone may buffer crust-mantle decoupling. In the WQL, the fast-axis direction is consistently and strongly NW-oriented from crust to upper mantle, revealing the vertically coherent deformation in its weakened lithosphere. Conversely, the central Qinling Orogenic Belt and northern Yangtze Block are characterized by high-velocity lithospheres with weak anisotropy, indicating stable tectonic features and being less directly affected by the plateau expansion. The differential responses of these lithospheric blocks to the eastward plateau expansion reflect complex deep dynamic processes in the region.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"922 ","pages":"Article 231043"},"PeriodicalIF":2.6,"publicationDate":"2026-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145785282","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":"Definition of the Andean seismogenic-active front in the Malargüe fold and thrust belt using a local seismic network and gravity data","authors":"Marianela Lupari ,&nbsp;Héctor P.A. García ,&nbsp;Silvina Nacif ,&nbsp;Andrés Folguera ,&nbsp;Francisco Ruiz","doi":"10.1016/j.tecto.2025.231052","DOIUrl":"10.1016/j.tecto.2025.231052","url":null,"abstract":"<div><div>This study focuses on the central sector of the Malargüe Fold and Thrust Belt (35.5°–36.5°S), where the limited crustal seismicity of the Payenia volcanic field and the presence of Quaternary deposits complicate the delineation of the neotectonic front and the identification of active structures. The deployment of a seismological network enabled the recording of local seismicity, revealing hypocenters clustered into two main groups in the upper crust, associated with NE–SW oriented basement structures. Focal mechanism analysis indicates a predominance of dextral strike-slip faulting with subordinate reverse components, while gravity data link the earthquakes to the source bodies generating the main anomalies. Group A activity reflects deformation accommodated by dextral basement faults modulated by reverse motion, with implications for hydrocarbon migration and accumulation. Group B highlights the interaction between deep structures, upper-crustal anisotropies, and active magmatic processes beneath the Payún Matrú volcano. These findings suggest that both inherited structures and mantle-related thermal anomalies (SWAP) govern stress distribution and seismicity in the region.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"922 ","pages":"Article 231052"},"PeriodicalIF":2.6,"publicationDate":"2026-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145823482","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":"Mesozoic differential uplift-exhumation processes in the western Tian Shan, Uzbekistan: Constraints from apatite/zircon fission track and (UTh)/He thermochronology","authors":"Weini Zhang ,&nbsp;Wengao Zhang ,&nbsp;Fengbin Han ,&nbsp;Jian Chang ,&nbsp;Hailong Huo ,&nbsp;Jiayong Pan ,&nbsp;Bakhtiar Nurtaev ,&nbsp;Shukhrat Shukurov ,&nbsp;Zhengle Cheng","doi":"10.1016/j.tecto.2026.231068","DOIUrl":"10.1016/j.tecto.2026.231068","url":null,"abstract":"<div><div>The western Tian Shan in Uzbekistan, forming the orogen's western terminus, provides critical insights into Meso-Cenozoic tectonic evolution through its uplift-exhumation history. This study integrates apatite/zircon fission-track (AFT/ZFT) and zircon (U<img>Th)/He analyses on 15 granitic samples from the Kyzylkum Nurata segment. Key findings include: (1) AFT ages span 67.50 ± 10.03–215.31 ± 14.53 Ma, with short mean track lengths (11.47 ± 1.38–12.65 ± 0.75 μm), indicating partial thermal resetting.(2)The western Tian Shan experienced Meso-Cenozoic multi-phase rapid uplift-exhumation, revealing a progressive northwest-to-southeast younging of apatite fission track ages and a marked contrast in exhumation regimes between the northwestern Nurata Range and adjacent ranges within the Kyzylkum-Nurata segment, highlighting spatiotemporal migration of tectonic activity and localized deformation partitioning. (3) Three thermo-tectonic phases were identified: Triassic rapid exhumation responding to Turan-Qiangtang/Paleo-Asia collision; Jurassic-Early Cretaceous uplift controlled by Lhasa-Qiangtang collision effects; Late Cretaceous-Cenozoic burial-rejuvenation cycles linked to Kohistan-Dras arc accretion in the Late Cretaceous and India-Eurasia/Kunlun-Pamir collisions in the Cenozoic. Differential exhumation patterns reflect inherited crustal heterogeneity, suture zone reactivation, and far-field stresses from Tethyan plate interactions. This study fills critical gaps in understanding Meso-Cenozoic uplift-exhumation processes in the westernmost Tian Shan, providing enhanced constraining models for the tectonic evolution of the entire orogen. Based on the investigation into the dynamic origins of uplift and exhumation, it can be concluded that the trend of uplift and exhumation in the Kyzylkum-Nurata segment of the Western Tian Shan propagated from southeast to northwest.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"922 ","pages":"Article 231068"},"PeriodicalIF":2.6,"publicationDate":"2026-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145894828","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":"Frictional strength and stability of laterally heterogeneous faults under fluid diffusion conditions","authors":"Shaobo Han ,&nbsp;Xiaoying Zhuang ,&nbsp;Wei Feng ,&nbsp;Quanzhou Yao ,&nbsp;Qianlong Zhou ,&nbsp;Xiaodong Hu","doi":"10.1016/j.tecto.2025.231057","DOIUrl":"10.1016/j.tecto.2025.231057","url":null,"abstract":"<div><div>Rock heterogeneity and fluids are widespread in natural fault zones. How they interplay to affect fault strength and frictional stability remains inadequately understood, particularly taking fluid diffusion into account. Here, we develop a two-degree-of-freedom spring-slider model based on rate-and-state friction (RSF) to investigate the frictional behavior of heterogeneous faults including quartz- and clay-rich gouges. Our model incorporates lateral fluid diffusion and pore pressure interactions between two fault gouge segments. Our results show that the increase in clay content within a quartz-rich fault causes a progressive weakening in fault strength and enhanced frictional stability. In quartz-dominated faults, high hydraulic diffusivity significantly delays the initiation of stick-slip instabilities. Our results replicate a full spectrum of slip behaviors from stable creep, slow slip, to dynamic rupture with controlled fault composition, friction parameter ratios and fluid diffusivity properties. We demonstrate that pore pressure perturbations, especially inter-patch pressure differences under fluid diffusion conditions, can drive slip behavior transitions. Our findings provide a physical framework for understanding seismic and aseismic slip behavior in fluid-rich, heterogeneous subduction-zone fault gouges.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"922 ","pages":"Article 231057"},"PeriodicalIF":2.6,"publicationDate":"2026-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145886488","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":"Stratigraphic and provenance analysis of the Alamor–Lancones Basin: Implications for the Cretaceous–Paleocene tectono–magmatic evolution of the northern Andean forearc system","authors":"Hugo Carrasco ,&nbsp;Cristian Vallejo ,&nbsp;Cristian Nuñez ,&nbsp;José Herrera ,&nbsp;Lily J. Jackson ,&nbsp;Brian K. Horton ,&nbsp;Tonny Thomsen ,&nbsp;Pieter Vermeesch ,&nbsp;Wilfried Winkler","doi":"10.1016/j.tecto.2025.231037","DOIUrl":"10.1016/j.tecto.2025.231037","url":null,"abstract":"<div><div>The Cretaceous–Paleocene Alamor–Lancones Basin is a well-preserved and long-lived forearc basin in southwestern Ecuador and northwestern Peru. It occupies a key morphotectonic region of the northern Andes, where the forearc transitions from continental basement in the south to accreted oceanic terranes in the north. This study investigates the stratigraphic evolution of the basin through provenance analysis of siliciclastic units and their response to fluctuating tectonic regimes that influenced the region. The oldest basin fill corresponds to the fluvial–alluvial Sábalos Formation, which unconformably overlies marine Paleozoic metasedimentary rocks of the El Tigre Unit. Whereas the lower Sábalos Formation was derived from exhuming crustal rocks, the upper levels record increasing input from coeval Aptian–early Albian volcanism. A shift to an extensional tectonic regime led to mid-Cretaceous lithospheric thinning, normal faulting, and submarine mafic volcanism of the continental Celica–Lancones Arc (∼105–91 Ma). Extension-related subsidence resulted in a transition to marine sedimentation, as recorded by the Puyango and Ciano formations during the middle Albian–Turonian. Following a Santonian compressional event (∼85 Ma), deep-marine deposition of the Zapotillo Group in the basin documents pre-, syn-, and post-accretion of the Caribbean Large Igneous Province (CLIP). Pre-accretional forearc sedimentation, as represented by the Santonian–late Campanian Chaquino and Tronco Quemado formations, records magmatic arc provenance with minor continental basement input. A latest Campanian–Maastrichtian shift to dominantly crustal provenance within the Mangahurco and Cañaveral formations provides evidence for exhumation of forearc basement rocks north of the basin in response to accretion of the CLIP at ∼75–70 Ma. Post-accretional accumulation of the Cazaderos and Casanga formations (∼66 Ma) recycled late Maastrichtian–Paleocene magmatic arc detritus from the emerging continental Sacapalca Arc. Overall, the evolution of the Alamor–Lancones Basin highlights how temporal shifts in the regional tectonic regime exerted first-order control on forearc deformation (basin subsidence and inversion), sediment provenance, and coeval arc magmatism, the latter also recorded by detrital zircon Th/U ratios.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"921 ","pages":"Article 231037"},"PeriodicalIF":2.6,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145753516","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 emplacement of an intraplate volcanic system in the Xiangshan Basin, Southeast China, implied from resistivity constrained 3D gravity and magnetic joint inversion","authors":"Min Feng ,&nbsp;Juzhi Deng ,&nbsp;Hui Yu ,&nbsp;Hui Chen ,&nbsp;Yunong Wei ,&nbsp;Yanguo Wang ,&nbsp;Xiao Chen","doi":"10.1016/j.tecto.2025.231054","DOIUrl":"10.1016/j.tecto.2025.231054","url":null,"abstract":"<div><div>The intraplate volcanic system in Xiangshan basin provides the main source of ore-forming materials for the world's third-largest volcanogenic uranium deposit. Although geological evidence suggests the existence of two volcanic cycles, the geometries of complete volcanic systems remain enigmatic and are not fully understood, as are the underlying emplacements responsible, due in part to the lack of sufficient geophysical data. To refine the structure of the volcanic system, we applied a gravity-magnetic joint inversion constrained by the resistivity model. The results delineated the first volcanic cycle rhyodacite conduit beneath the Shutang area in the western basin, characterized by high susceptibility and dipping southwest in the shallow subsurface, with its emplacement controlled by a low-density east–west-trending basement fault activated by regional north-south extension stresses. The second volcanic cycle porphyroclastic lava conduit, characterized by low density and high susceptibility, dips southeastward and extends toward the northeast flank of Mount Xiangshan. In the west, the high susceptibility of the first-cycle volcanic conduit suggests that the second-cycle porphyroclastic lava conduit may have inherited the earlier magmatic pathway, with its emplacement jointly controlled by low-density regional north–south basement faults activated by east–west extension stresses and pre-existing east–west structures. These results underscore the dominant role of regional tectonic environments in controlling the multi volcanic cycles and provide new insight for emplacement mechanisms in a strike-slip extension environment.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"921 ","pages":"Article 231054"},"PeriodicalIF":2.6,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145813957","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":"Crustal structure and tectonic implications of the Southern Central Asian Orogenic Belt: New insights from gravity, magnetic, and magnetotelluric imaging","authors":"Chutong Chen ,&nbsp;Na Li ,&nbsp;Lingxiao Zhang ,&nbsp;Hongying An ,&nbsp;Chang’an Guo ,&nbsp;Xing Fu ,&nbsp;Songda Lei ,&nbsp;Guicai Yang ,&nbsp;Junjie Fan ,&nbsp;Weiheng Yuan ,&nbsp;Hao Wang ,&nbsp;Bin Wang ,&nbsp;Kunpeng Wang","doi":"10.1016/j.tecto.2025.231053","DOIUrl":"10.1016/j.tecto.2025.231053","url":null,"abstract":"<div><div>The Alxa and Beishan domains experienced extensive arc-related magmatism during the closure of the Paleo Asian Ocean, followed by long-lived intracontinental deformation. Widespread sedimentation has obscured their deep structures and mutual relations. Here we integrate gravity, magnetic, and magnetotelluric data to refine the crustal structures and evaluate the tectonic linkage between the Alxa and Beishan domains. Geophysical contrasts across the Quagan Qulu–Tebai suture identify it as a major lithospheric boundary, separating accretionary complexes in the north from continental lithosphere in the south. In southern Alxa, magnetic and gravity anomalies delineate two concealed early Permian arc belts, whose spatial alignment with ductile strike-slip zones suggests their localization along lithospheric weaknesses during post-collisional transpression. Across the Alxa–Beishan boundary, east–west ophiolitic magnetic highs are not directly continuous. Northeast-trending faults, including the Sanweishan and Ruoshui faults, disrupt the boundary, and the gravity field indicates a discontinuous rather than uniform crustal architecture. These geophysical observations support the view that a direct connection between the Alxa and Beishan is unlikely. The Sanweishan fault is identified as a crustal-scale structure that, together with the Xingxingxia and Ruoshui faults, forms a major fault system distributed in the Beishan domain. Collectively, these results highlight segmented tectonic domains and largely independent Mesozoic deformation in Alxa and Beishan, offering new geophysical constraints on their crustal architecture and mutual tectonic linkage.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"921 ","pages":"Article 231053"},"PeriodicalIF":2.6,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145823483","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":"Finite element modelling of evaporite flow constrained by kinematic markers in the Messinian of the Eastern Mediterranean","authors":"Daniel Phillips ,&nbsp;Daniel Roberts ,&nbsp;Martino Foschi ,&nbsp;Ben Aldridge ,&nbsp;Joe Cartwright","doi":"10.1016/j.tecto.2025.231058","DOIUrl":"10.1016/j.tecto.2025.231058","url":null,"abstract":"<div><div>Salt has the unique ability to flow on geological timescales in response to even low differential stresses. This has facilitated the formation of complex structures in many sedimentary basins globally. Since many salt basins experience multiple deformational phases after deposition, disentangling the key drivers of deformation is often challenging. Here, we use basin-scale numerical modelling focusing on the geological creep of salt in order to recreate displaced fluid escape pipes acting as kinematic markers in the Eastern Mediterranean. We use a parameter sweep to demonstrate that a numerical solution of the maximum horizontal pipe displacement is contained within realistic values of basinal tilt and evaporite rheologies. Optimal modelled flow profiles were found to be parabolic, with lower viscosity models tending to a sigmoidal solution and higher viscosity models tending to a laminar linear solution. There are significant discrepancies between model-derived flow profiles and idealised Couette flow, which may lead to challenges regarding prior bulk flow reconstructions. These results are uniquely observationally constrained, and provide insights into the driving forces behind basin-scale salt flow, along with the stress evolution of basins and the nature of passive strain markers within evaporite sequences.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"921 ","pages":"Article 231058"},"PeriodicalIF":2.6,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145842551","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":"Imaging the northern Zagros collision zone by ambient noise and earthquake surface wave tomography","authors":"Zahra Zarunizadeh ,&nbsp;Abdelkrim Aoudia ,&nbsp;Khalil Motaghi ,&nbsp;Surya Pachhai ,&nbsp;Daniel Manu-Marfo ,&nbsp;Yingjie Yang ,&nbsp;Wathiq Abdulnaby ,&nbsp;Yinshuang Ai ,&nbsp;Ling Chen","doi":"10.1016/j.tecto.2025.231041","DOIUrl":"10.1016/j.tecto.2025.231041","url":null,"abstract":"<div><div>The Zagros collision zone provides a natural laboratory for investigating the early stages of continental collision and mountain building. This study presents Rayleigh wave phase and group velocity tomography for the northern Zagros, using new seismic data from western Iran and eastern Iraq. Ambient noise tomography for both group and phase velocities was conducted over periods of 7–35 s. In addition, earthquake data were used to compute phase velocity tomograms for periods of 29–100 s, employing a two-plane-wave tomography technique. Nonlinear inversion of node-wise dispersion curves from both group and phase velocity dispersion data produced a 3-D shear-wave velocity (Vs) model extending to a depth of 200 km. The Vs model reveals: (1) a mid-crustal low-velocity layer (20–30 km depth) beneath the Zagros suture, extending 100–250 km northward with spatial variability; (2) a high-velocity anomaly (Vs ∼3.6 km/s) at 5–20 km depth beneath the Sanandaj-Sirjan zone, interpreted as the exhumed Zagros crystalline core at the overriding margin of Central Iran; and (3) a high-velocity lithospheric mantle (Vs ∼4.7 km/s) with varying lateral extent and thickness along the orogen. These features point to differing convergence mechanisms, with underthrusting dominating in the northwest and a combination of underthrusting and internal deformation in the southeast. Furthermore, a thinner Arabian lithosphere in the northwestern Zagros, compared to thicker lithosphere elsewhere, suggests ongoing partial delamination in the lower portion of the lithospheric mantle.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"921 ","pages":"Article 231041"},"PeriodicalIF":2.6,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145785280","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}