Tectonophysics最新文献_第5页

Inference of the Gutenberg-Richter b-value: New insights and results 古腾堡-里希特 b 值的推断：新的见解和结果

IF 2.7 3区地球科学

Tectonophysics Pub Date : 2024-08-27 DOI: 10.1016/j.tecto.2024.230486

Eulogio Pardo-Igúzquiza , Peter A. Dowd

{"title":"Inference of the Gutenberg-Richter b-value: New insights and results","authors":"Eulogio Pardo-Igúzquiza , Peter A. Dowd","doi":"10.1016/j.tecto.2024.230486","DOIUrl":"10.1016/j.tecto.2024.230486","url":null,"abstract":"<div><p>The size-frequency distribution of many geological and geophysical variables, in relation to fractures, faulting and seismicity, is well described by a statistical distribution of the power law type which is characterized by its exponent. For earthquake magnitudes, the exponent is the well-known <em>b</em>-parameter of the Gutenberg-Richter scaling law. In this paper we:</p><ul><li><span>•</span><span><p>provide a strict statistical derivation of the distribution law of earthquake magnitudes,</p></span></li><li><span>•</span><span><p>show that the maximum likelihood estimator of the <em>b</em>-parameter is unbiased,</p></span></li><li><span>•</span><span><p>demonstrate that the maximum likelihood estimator is invariant to the value chosen as the minimum magnitude threshold in so far as it is larger than the magnitude of completeness of the earthquake catalogue, and</p></span></li><li><span>•</span><span><p>provide a new estimator based on the minimization of the Kolmogorov-Smirnov statistic and provide a strategy for detecting and mapping the spatio-temporal variation of the <em>b</em>-parameter in seismic swarms.</p></span></li></ul><p>The findings are illustrated with simulated data and a case study with real data.</p></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0040195124002889/pdfft?md5=4a7c102349b09a342138fdb4e7bc30b6&pid=1-s2.0-S0040195124002889-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142168851","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}

引用次数: 0

Analysis of stress field in the head area of the Three Gorges Reservoir based on coupled fluid-solid theory 基于流固耦合理论的三峡库区水头区应力场分析

IF 2.7 3区地球科学

Tectonophysics Pub Date : 2024-08-22 DOI: 10.1016/j.tecto.2024.230482

Yiming Dai , Lili Zhang , Yaowen Zhang , Yunsheng Yao , Renlong Wang

{"title":"Analysis of stress field in the head area of the Three Gorges Reservoir based on coupled fluid-solid theory","authors":"Yiming Dai , Lili Zhang , Yaowen Zhang , Yunsheng Yao , Renlong Wang","doi":"10.1016/j.tecto.2024.230482","DOIUrl":"10.1016/j.tecto.2024.230482","url":null,"abstract":"<div><p>The Three Gorges Reservoir, one of the largest water conservation system in the world, has been of keen interest to scientists globally since its impoundment. After construction of the dam, there has been a significant increase in seismic activity in the head area of the reservoir. It is generally accepted that earthquakes in this region are predominantly caused by the Jiuwanxi and Xiannvshan faults. This study focused on the stress changes occurring in the research area. A three-dimensional finite element model of the reservoir area was constructed using the geological structure and digital ground elevation data of the reservoir area. The fluid-solid coupling theory was applied to calculate the dynamic spatial changes in pore pressure and Coulomb stress in the faults and surrounding rocks during reservoir impoundment. The findings indicated that the added head pore water pressure at the bottom of the reservoir had a maximum impact range of approximately −2800 m on the surrounding rock, whereas the Xiannvshan and Jiuwanxi faults had a maximum diffusion range of approximately −4300 m. Rock permeability also played a significant role in the water storage process. During the 1 56 m water impoundment stage, owing to rapid water storage activity, stress could not be transmitted to both sides in a timely manner, resulting in the formation of an extreme stress change zone at −4000 m inside the fault. This may have been the reason for the frequent earthquakes during this stage. The 17 5 m cycle water storage stage also exhibited a significant degree of seismicity, potentially attributable to the long-term infiltration of reservoir water and accumulation of stress in the previous stage. The stress in the study area at the four stages are in a process of accumulation-release-accumulation-release.</p></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142057996","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}

引用次数: 0

Co-seismic and post-seismic slip associated with the 2021 Mw5.9 Arkalochori, Central Crete (Greece) earthquake constrained by geodetic data and aftershocks 由大地测量数据和余震制约的与 2021 年希腊克里特岛中部 Arkalochori 5.9 级地震相关的共震和震后滑动

IF 2.7 3区地球科学

Tectonophysics Pub Date : 2024-08-22 DOI: 10.1016/j.tecto.2024.230481

Pavlos Bonatis , Vasileios Karakostas , Jan Kaplon , Eleftheria Papadimitriou , George Kaviris , Maya Ilieva , Michael Foumelis , Christos Pikridas

{"title":"Co-seismic and post-seismic slip associated with the 2021 Mw5.9 Arkalochori, Central Crete (Greece) earthquake constrained by geodetic data and aftershocks","authors":"Pavlos Bonatis , Vasileios Karakostas , Jan Kaplon , Eleftheria Papadimitriou , George Kaviris , Maya Ilieva , Michael Foumelis , Christos Pikridas","doi":"10.1016/j.tecto.2024.230481","DOIUrl":"10.1016/j.tecto.2024.230481","url":null,"abstract":"<div><p>The co-seismic and post-seismic deformation field associated with the M<sub>w</sub>5.9 Arkalochori main shock that occurred in central Crete (Greece) on 27 September 2021 is analyzed using Copernicus Sentinel-1A & 1B images, GNSS measurements and seismological data. The fault geometry is constrained through the joint inversion of multiple datasets and the slip distribution for the co-seismic and post-seismic period is obtained using a homogeneous half-space elastic model and the Steepest Descent Method. The results indicate a blind normal fault striking 215° with a 55° dip to the northwest and the co-seismic slip model suggests a nearly circular main slip patch (8 × 6 km<sup>2</sup>) with a maximum slip of 0.98 m. Post-seismic displacements started rapidly after the main shock followed by a gradual decay as highlighted by the calculated InSAR time series. The temporal evolution of post-seismic slip is described by a simple logarithmic function, decaying faster at the southwest part of the fault. The cumulative afterslip model suggests that the maximum post-seismic slip of 0.23 m occurred within a similar depth range compared to the co-seismic one, yet with a shift towards the southwest. Post-seismic slip inside the main shock rupture area is sustained, highlighting the slow recovery of locking in the co-seismic slip region. Afterslip (seismic or aseismic) played a dominant role in the early post-seismic period acting complementarily to the main rupture. Indications suggest that the spatiotemporal evolution of the productive aftershock sequence may be driven afterslip, alongside other potential factors.</p></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142058009","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}

引用次数: 0

Fault rock properties and conditions produce variance in slip during earthquake rupture propagation at the Nankai Trough 断层岩特性和条件在南海海槽地震破裂传播过程中产生的滑移差异

IF 2.7 3区地球科学

Tectonophysics Pub Date : 2024-08-22 DOI: 10.1016/j.tecto.2024.230483

Kenichi Tsuda , Tetsuro Hirono

{"title":"Fault rock properties and conditions produce variance in slip during earthquake rupture propagation at the Nankai Trough","authors":"Kenichi Tsuda , Tetsuro Hirono","doi":"10.1016/j.tecto.2024.230483","DOIUrl":"10.1016/j.tecto.2024.230483","url":null,"abstract":"<div><p>Although drilled samples of fault rocks have yielded information on frictional features of shallow subduction zones, the relationship of rupture propagation to the levels of friction and pore-fluid pressure remains uncertain. To investigate this topic, we performed dynamic rupture simulations along the megasplay fault that slipped during the 1944 M<sub>w</sub> 8.0 Tonankai earthquake in the Nankai Trough. We used actual data from friction experiments on rocks from the fault segment and pre-existing pore pressures deduced from geophysical surveys for the shallow portion of 0–10 km depth along the fault. Simulations of low friction (friction coefficient ca. 0.04) produced large slip (about 30 m), whereas simulations using higher friction (friction coefficient ca. 0.2) suppressed the rupture. In simulations with low friction in which the pore-fluid pressure was nearly equal to the lithostatic stress, the slip decreased to about 25 m. However, when the simulations included slip-strengthening at shallow depth and higher friction, the slip still reached roughly 20 m. Such variability in slip during rupture propagation is caused by differences in the friction features and fluid pressure conditions of fault rocks, in which the friction features might be related to the mineral composition. Spatiotemporal heterogeneity in fault-rock type and their physical and hydraulic properties may fundamentally produce the complexity and variability of earthquake rupture propagation along the Nankai plate-subduction boundary.</p></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142097691","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}

引用次数: 0

Unraveling the link between magma and deformation during slow seafloor spreading 揭示缓慢海底扩张过程中岩浆与变形之间的联系

IF 2.7 3区地球科学

Tectonophysics Pub Date : 2024-08-20 DOI: 10.1016/j.tecto.2024.230473

Yanghui Zhao , Weiwei Ding , Gianreto Manatschal , Xiaodong Wei , Hanghang Ding , Zhengyi Tong , Jingyan Zhao

{"title":"Unraveling the link between magma and deformation during slow seafloor spreading","authors":"Yanghui Zhao , Weiwei Ding , Gianreto Manatschal , Xiaodong Wei , Hanghang Ding , Zhengyi Tong , Jingyan Zhao","doi":"10.1016/j.tecto.2024.230473","DOIUrl":"10.1016/j.tecto.2024.230473","url":null,"abstract":"<div><p>Detachment faulting related to oceanic core complexes (OCCs) has been suggested to be a manifestation of slow seafloor spreading. Although numerical models suggest OCCs form under low magma supply, the specific interaction between magmatism and tectonic faulting remains elusive. This paper examines seismic observations detailing the spatiotemporal interactions between magmatism, high-angle faulting, and detachment faulting at a slow-spreading mid-ocean ridge in the West Philippine Basin. We identified a magma-rich spreading phase, indicated by a magmatic top basement and oceanic crust with shallow-penetrating high-angle normal faults. An axial valley reveals an along-strike transition from magmatically-dominated to highly tectonized oceanic crust over a distance of 70 km. Two older OCCs with concave-down fault geometries and a younger OCC with steep-dipping faulting suggest sequential detachments with the same polarity. Our findings suggest: (1) slow seafloor spreading alternates between high-angle faulting with a relatively high magma supply and detachment faulting with a limited magma supply; (2) sequential development of younger detachments in the footwall of its predecessor leads to an asymmetric split in the newly accreted crust; and (3) the life cycle of OCC ends with high-angle faults that overprint the detachment and act as magma pathways, sealing the OCC. Our study captures the dynamic interaction between high-angle and detachment faults and their concurrent and subsequent relationship to magmatic systems. This reveals that strain distribution along strike is critical to OCC formation, thus enriching our understanding beyond conventional considerations such as spreading rates and melt budgets at mid-ocean ridges.</p></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0040195124002750/pdfft?md5=8a87f337de0d89fa41676fb2743e198e&pid=1-s2.0-S0040195124002750-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142048997","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}

引用次数: 0

The influence of the strength of pre-existing weak zones on rift geometry and strain localization 原有薄弱带的强度对裂谷几何形状和应变定位的影响

IF 2.7 3区地球科学

Tectonophysics Pub Date : 2024-08-20 DOI: 10.1016/j.tecto.2024.230472

Liang Xue , Robert Moucha , Folarin Kolawole , James D. Muirhead , Christopher A. Scholz

{"title":"The influence of the strength of pre-existing weak zones on rift geometry and strain localization","authors":"Liang Xue , Robert Moucha , Folarin Kolawole , James D. Muirhead , Christopher A. Scholz","doi":"10.1016/j.tecto.2024.230472","DOIUrl":"10.1016/j.tecto.2024.230472","url":null,"abstract":"<div><p>Continental rifts normally initiate within previously deformed lithosphere and thus their evolution and architecture can be largely controlled by inherited weak zones in the pre-rift crust. Here, we quantify the role of the strength and obliquity of pre-existing crustal-scale weak zones in the evolution of continental rift systems. We use a 3D numerical geodynamic model to assess strain localization, associated fault development, and rift segmentation during the early stages of tectonic extension. We find that both the strength and obliquity of the weak zones significantly influence the patterns of strain localization. A pre-existing very weak zone with low obliquity can promote the development of continuous and long-lived border faults parallel to the rift axis. Conversely, a comparatively strong weak zone with high obliquity leads to a staggered en-echelon rift geometry that lacks rectilinear laterally persistent strain localization. Furthermore, we find that rift obliquity and weak zone strength may modulate rift fault length, throw, and azimuth. These results provide new and compelling insights into the structure and evolution of natural active rifts that develop within orogenic basement terranes.</p></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142089050","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}

引用次数: 0

Shaping the crustal structure of the SW-Alpine Foreland: Insights from 3D Geological modeling 塑造西南阿尔卑斯山前陆的地壳结构：三维地质建模的启示

IF 2.7 3区地球科学

Tectonophysics Pub Date : 2024-08-20 DOI: 10.1016/j.tecto.2024.230471

Dorian Bienveignant , Ahmed Nouibat , Christian Sue , Yann Rolland , Stéphane Schwartz , Matthias Bernet , Thierry Dumont , Jérôme Nomade , Séverine Caritg , Andrea Walpersdorf

{"title":"Shaping the crustal structure of the SW-Alpine Foreland: Insights from 3D Geological modeling","authors":"Dorian Bienveignant , Ahmed Nouibat , Christian Sue , Yann Rolland , Stéphane Schwartz , Matthias Bernet , Thierry Dumont , Jérôme Nomade , Séverine Caritg , Andrea Walpersdorf","doi":"10.1016/j.tecto.2024.230471","DOIUrl":"10.1016/j.tecto.2024.230471","url":null,"abstract":"<div><p>Reactivation processes play a significative role in the localization of deformation but still remain hard to establish at the lithospheric scale. In this work, we built a 3D structural model, which enables to bridge the gap between the main tectonic structures observed at the surface and the geometry of the major interfaces (the Mohorovičić-discontinuity (hereafter Moho) and top of the basement) inferred from geophysical data acquired in the external Western Alps and their foreland. The geometry of these tectonic structures is interpreted in relation to their geodynamic evolution. The main results of this study highlight: (1) a strong contribution of thick-skinned Pyrenean-Provence and Alpine tectonics, (2) a lithospheric rooting of Variscan shear zones and related faults, and (3) the regional-scale influence of these inherited structures on the post-Paleozoic strain localization in the study area. Our 3D model shows that the pattern of Variscan shear zones that were developed at the end of the Paleozoic involved the whole crust, as emphasized by the Moho offsets. These shear zones were reactivated and localized Meso-Cenozoic deformation. The Variscan deformation pattern controlled the geometry of extensional basins, the propagation of Pyrenean-Provence deformation, and finally the Alpine deformation at crustal scale. Our 3D model shows minor crustal thickening (ca. 40 km) located below the Pelvoux External Crystalline Massif, which probably resulted from both Pyrenean and Alpine tectonic phases. In contrast, the southern part of the Alpine front shows a thinned crust (ca. 18 km) resulting from extensional Meso-Cenozoic phases between the Cévennes margin and the Durance basin.</p></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142020806","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}

引用次数: 0

Evolution of the transtensional Barreirinhas pull-apart system in the Brazilian Equatorial margin and its correlation with the African conjugate counterpart 巴西赤道边缘横向巴雷里尼亚斯拉分系统的演变及其与非洲共轭对应系统的相关性

IF 2.7 3区地球科学

Tectonophysics Pub Date : 2024-08-15 DOI: 10.1016/j.tecto.2024.230470

David L. de Castro, Diógenes C. Oliveira, Francisco H.R. Bezerra

{"title":"Evolution of the transtensional Barreirinhas pull-apart system in the Brazilian Equatorial margin and its correlation with the African conjugate counterpart","authors":"David L. de Castro, Diógenes C. Oliveira, Francisco H.R. Bezerra","doi":"10.1016/j.tecto.2024.230470","DOIUrl":"10.1016/j.tecto.2024.230470","url":null,"abstract":"<div><p>The Barreirinhas pull-apart system encompasses marginal basins in divergent and transform margin segments in the central sector of the Brazilian Equatorial Margin and its African conjugate counterpart. This ancient pull-apart system evolved through transtensional strike-slip motion within a highly heterogeneous crystalline basement affected by multiple rift phases. The geometry and development of pull-apart structural elements during the final rifting phase before continental breakup and the mechanisms and extent to which they were influenced by preexisting crustal heterogeneities are comprehensively addressed using an extensive database of potential field (magnetic and gravity) and 2D seismic reflection data. We also assess the lithospheric thermomechanical conditions and their influence on transtensional extension throughout Curie Point Depth, Heat Flow, and Moho depth, derived from potential field data and published seismological models. Plate reconstruction of Brazilian and African equatorial margins based on gravity patterns and comparison with sandbox analog models allow a 3D synoptic model to reveal the Barreirinhas pull-apart system evolution during the Equatorial Atlantic opening. During the rift phase I, the location of major grabens was controlled by favorably oriented Neoproterozoic shear zones, while the cooler, stronger, and thicker crust beneath cratonic areas formed the western barrier to strike-slip rift activity during rift phase II. This same geological domain anchored the onset of the pull-apart system in the last rift phase III, whose principal displacement zones developed along the extensive oceanic fracture zones linked by sigmoidal fault systems. Toward the end of the rift phase, a large asymmetric lozangle to a lazy-<em>Z</em>-shaped, pull-apart basin developed above low overlapping ∼90°, releasing stepover in oblique transtensional strike-slip motion.</p></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142011411","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}

引用次数: 0

Machine-learning based location of the 2021 MW 7.4 Maduo, Qinghai, China earthquake sequence: Insight into intraplate seismogenesis 基于机器学习的中国青海玛多 2021 MW 7.4 级地震序列定位：洞察板块内地震发生

IF 2.7 3区地球科学

Tectonophysics Pub Date : 2024-08-13 DOI: 10.1016/j.tecto.2024.230458

Penghu Guan , Jianshe Lei , Dapeng Zhao

{"title":"Machine-learning based location of the 2021 MW 7.4 Maduo, Qinghai, China earthquake sequence: Insight into intraplate seismogenesis","authors":"Penghu Guan , Jianshe Lei , Dapeng Zhao","doi":"10.1016/j.tecto.2024.230458","DOIUrl":"10.1016/j.tecto.2024.230458","url":null,"abstract":"<div><p>On 22 May 2021, an <em>M</em><sub>W</sub> 7.4 earthquake occurred in Maduo County, Qinghai Province, China, which is located on the Kunlun Mountain Pass-Jiangcuo fault inside the Bayan Har block, providing a good opportunity to investigate seismogenesis of large intraplate earthquakes. We analyze two years of continuous seismic data from June 2021 to June 2023, which were recorded at 34 portable seismic stations of the MaduoArray deployed in the source zone by our group. The LOC-FLOW workflow of automatic detection and location is applied to construct a complete and high-precision seismic catalog for the region, which includes machine-learning phase picking (PhaseNet), earthquake phase association (REAL), velocity model updating and station correction (VELEST), absolute earthquake location (HypoInverse), and relative location (HypoDD). As a result, 78,832 Maduo aftershocks and other local earthquakes are detected and relocated precisely. Our results show that the length of the Maduo aftershock zone is ∼170 km, which is mainly distributed along the NWW-SEE oriented Kunlun Mountain Pass-Jiangcuo fault, and there is a horsetail bifurcation feature at the eastern end of the aftershock sequence. The seismogenic fault is nearly vertical, and local seismicity occurs on both sides of the fault. Our results also show that there is no seismic gap or aftershock sparse area in the region. Previous studies have revealed a low-velocity and high-conductivity anomaly below the source zone, reflecting fluids ascending from the lower crustal flow. These results provide new insights into the cause of the 2021 Maduo earthquake.</p></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141978432","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}

引用次数: 0

Teleseismic measurements of Upper Mantle Shear-Wave Anisotropy in Southern Mexico 墨西哥南部上地幔剪切波各向异性的远震测量结果

IF 2.7 3区地球科学

Tectonophysics Pub Date : 2024-08-13 DOI: 10.1016/j.tecto.2024.230465

Samuel Celis , Luis Vázquez , Raúl W. Valenzuela , Laura Petrescu , Xyoli Pérez-Campos , Gerardo León Soto

{"title":"Teleseismic measurements of Upper Mantle Shear-Wave Anisotropy in Southern Mexico","authors":"Samuel Celis , Luis Vázquez , Raúl W. Valenzuela , Laura Petrescu , Xyoli Pérez-Campos , Gerardo León Soto","doi":"10.1016/j.tecto.2024.230465","DOIUrl":"10.1016/j.tecto.2024.230465","url":null,"abstract":"<div><p>The Mexican subduction system is an ideal region to study 3-D mantle deformation patterns in response to changes in slab geometry and the presence of tears. Shear-wave splitting measurements were made using <em>SKS, SKKS,</em> and <em>PKS</em> waves in southern Mexico, where the Cocos slab subducts beneath the North American and western Caribbean plates. For most of southern Mexico, the results are consistent with predominantly trench-normal fast polarization directions that can be interpreted as a consequence of sub-slab entrained flow and 2-D corner flow in the mantle wedge in the presence of A-type olivine fabric (or similar). This pattern of trench-perpendicular fast axes extends northward to the region southeast of the Trans-Mexican Volcanic Belt. Beneath its eastern end, fast axes rotate ∼20° clockwise and are likely controlled by the absolute motion of the North American plate. In southeastern Mexico, along the coast and above the mantle wedge tip, the fast axes are trench-normal and the delay times are the shortest. They were interpreted to result from a possibly serpentinized mantle wedge tip. In the same region above the mantle wedge core, the splitting parameters appear to result from different flow patterns in the mantle wedge and the sub-slab mantle.</p></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":null,"pages":null},"PeriodicalIF":2.7,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141978385","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}

引用次数: 0