首页 > 最新文献

Tectonophysics最新文献

英文 中文
Spatially varying stress regime in the southern Junggar Basin, NW China 中国西北部准噶尔盆地南部空间变化的应力机制
IF 2.7 3区 地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2024-10-10 DOI: 10.1016/j.tecto.2024.230516
Lin Wu , Xingqiang Feng , Lei Zhou , Shuwei Guan , Dongsheng Ji , Yuanlong Tan , Linyan Zhang
The southern Junggar Basin in NW China is an important tectonic unit in the region of the Tibetan Plateau and has been the focus of considerable research into its tectonic processes and geodynamic setting. However, the relationship between deep structural deformation and stress in this region remains unclear. This study investigates the Gaoquan and Hutubi anticlines in the southern Junggar Basin using three-dimensional geophysical data and a finite-element numerical simulation to examine the crustal stress distribution and stress regime at depths of up to 7 km. Numerical simulation results indicate that the stress regime in the southern Junggar Basin changes from west to east. In the western part of the region, including the Gaoquan anticline at depths of 4900–6100 m, the maximum horizontal principal stress shows a peak of 140–200 MPa, the minimum horizontal principal stress is 110–170 MPa, and the vertical principal stress is 115–175 MPa, indicating a mixed stress regime incorporating both compression and strike-slip components. In the eastern part of the region, including the Hutubi anticline at depths of 5400–7800 m, the maximum horizontal principal stress shows a peak of 160–280 MPa, the minimum horizontal principal stress is 155–250 MPa, and the vertical principal stress is 125–215 MPa, indicating a compressive stress regime. The stress magnitude and orientation are affected by the presence of faults and depth in the crust. Combining these results with the regional tectonic setting, it is considered that the geometrical relationship between pre-existing faults and the current stress field is the main control on the west–east differentiation in the stress regime, with spatial variations in the mechanical parameters of the crust and the pressure coefficient being secondary factors. These results provide insights into the relationship between stress and deformation, and support the updated version of the World Stress Map database.
中国西北部准噶尔盆地南部是青藏高原地区的一个重要构造单元,其构造过程和地球动力学背景一直是大量研究的重点。然而,该地区深部构造变形与应力之间的关系仍不清楚。本研究利用三维地球物理数据和有限元数值模拟,研究了准噶尔盆地南部的高泉和呼图壁反斜,探讨了深达 7 千米的地壳应力分布和应力机制。数值模拟结果表明,准噶尔盆地南部的应力机制自西向东发生变化。在该地区的西部,包括4900-6100米深处的高泉反斜线,最大水平主应力的峰值为140-200兆帕,最小水平主应力为110-170兆帕,垂直主应力为115-175兆帕,表明该地区的应力体系包含了压缩和走向滑动两种成分。在该地区的东部,包括深度为 5400-7800 米的呼图壁反斜线,最大水平主应力的峰值为 160-280 兆帕,最小水平主应力为 155-250 兆帕,垂直主应力为 125-215 兆帕,表明这是一种压缩应力机制。应力大小和方向受断层的存在和地壳深度的影响。将这些结果与区域构造背景相结合,可以认为原有断层与当前应力场之间的几何关系是应力机制西-东分化的主要控制因素,而地壳力学参数和压力系数的空间变化则是次要因素。这些结果提供了对应力和变形之间关系的见解,并为更新版的世界应力图数据库提供了支持。
{"title":"Spatially varying stress regime in the southern Junggar Basin, NW China","authors":"Lin Wu ,&nbsp;Xingqiang Feng ,&nbsp;Lei Zhou ,&nbsp;Shuwei Guan ,&nbsp;Dongsheng Ji ,&nbsp;Yuanlong Tan ,&nbsp;Linyan Zhang","doi":"10.1016/j.tecto.2024.230516","DOIUrl":"10.1016/j.tecto.2024.230516","url":null,"abstract":"<div><div>The southern Junggar Basin in NW China is an important tectonic unit in the region of the Tibetan Plateau and has been the focus of considerable research into its tectonic processes and geodynamic setting. However, the relationship between deep structural deformation and stress in this region remains unclear. This study investigates the Gaoquan and Hutubi anticlines in the southern Junggar Basin using three-dimensional geophysical data and a finite-element numerical simulation to examine the crustal stress distribution and stress regime at depths of up to 7 km. Numerical simulation results indicate that the stress regime in the southern Junggar Basin changes from west to east. In the western part of the region, including the Gaoquan anticline at depths of 4900–6100 m, the maximum horizontal principal stress shows a peak of 140–200 MPa, the minimum horizontal principal stress is 110–170 MPa, and the vertical principal stress is 115–175 MPa, indicating a mixed stress regime incorporating both compression and strike-slip components. In the eastern part of the region, including the Hutubi anticline at depths of 5400–7800 m, the maximum horizontal principal stress shows a peak of 160–280 MPa, the minimum horizontal principal stress is 155–250 MPa, and the vertical principal stress is 125–215 MPa, indicating a compressive stress regime. The stress magnitude and orientation are affected by the presence of faults and depth in the crust. Combining these results with the regional tectonic setting, it is considered that the geometrical relationship between pre-existing faults and the current stress field is the main control on the west–east differentiation in the stress regime, with spatial variations in the mechanical parameters of the crust and the pressure coefficient being secondary factors. These results provide insights into the relationship between stress and deformation, and support the updated version of the World Stress Map database.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"891 ","pages":"Article 230516"},"PeriodicalIF":2.7,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142445894","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
Heterogeneous mineralogical composition and fault behaviour: A systematic study in ternary fault rock compositions 异质矿物成分与断层行为:三元断层岩成分的系统研究
IF 2.7 3区 地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2024-10-10 DOI: 10.1016/j.tecto.2024.230528
Roberta Ruggieri , Giacomo Pozzi , Giuseppe Volpe , Francesca Bottazzi , Marco Brignoli , Anna Antonia Irene Corradi , Stefano Mantica , Lorenzo Osculati , Stefania Petroselli , Giorgio Volontè , Cristiano Collettini
The heterogeneous mineralogical compositions of fault gouges, formed during fault evolution, influence frictional properties and slip behaviour. While the influence of individual mineral phases on friction has been extensively studied, the impact of varying systematically mineral phases in gouge mixtures on macroscopic frictional behaviour remains unclear. Thus, we performed 34 frictional experiments on fault gouges composed of three representative mineral phases: muscovite (platy phyllosilicate), quartz (granular silicate) and calcite (granular carbonate), known for their markedly distinct frictional properties. Using a biaxial rock deformation apparatus (BRAVA), we performed tests on fault gouges with grain sizes <125 μm under normal stresses of 50–100 MPa, at room temperature and water-saturated conditions. Our data indicate that the mineralogical composition of fault gouges significantly affects frictional strength, healing, and stability with a non-trivial pattern. Increasing the muscovite content leads to a decrease in frictional strength, from 0.62 for pure calcite and 0.56 for pure quartz to 0.33 of pure muscovite, along with reduced frictional healing and a velocity-strengthening behaviour. This weakening is promoted by a transition from localized deformation along discrete shear planes in granular-rich fault gouges to distributed deformation within the entire gouge layer with increasing muscovite content. At fixed muscovite content, frictional properties depend on the dominant granular phase. Calcite-dominated mixtures exhibit more marked frictional weakening rather than quartz-dominated ones, suggesting a non-linear mixing law between friction coefficient and muscovite content. This different trend is likely due to favourable conditions for fluid-assisted pressure-solution of calcite and foliation development, unlike quartz. When only the granular phases are mixed, we observe complex behaviour with the indentation of quartz into calcite, resulting in higher values of healing rates than those of pure end-member mixtures.
Our findings provide robust insights into microphysical processes strongly dependent on the complex mineralogical compositions usually observed along natural faults.
断层演化过程中形成的断层沟的异质矿物成分会影响摩擦特性和滑移行为。虽然单个矿物相对摩擦的影响已被广泛研究,但断层破碎带混合物中矿物相的系统变化对宏观摩擦行为的影响仍不清楚。因此,我们对由三种具有代表性的矿物相组成的断层冲沟进行了 34 次摩擦实验,这三种矿物相分别是:褐铁矿(板状硅酸盐)、石英(粒状硅酸盐)和方解石(粒状碳酸盐),它们以明显不同的摩擦特性而闻名。我们使用双轴岩石形变仪(BRAVA),在常温和水饱和状态下,在 50-100 兆帕的法向应力作用下,对晶粒大小为 125 微米的断层破碎带进行了测试。我们的数据表明,断层破碎带的矿物成分对摩擦强度、愈合和稳定性有显著影响,且影响模式并不复杂。黝帘石含量的增加会导致摩擦强度降低,从纯方解石的 0.62 和纯石英的 0.56 降至纯黝帘石的 0.33,同时摩擦愈合能力降低,速度增强。随着白云母含量的增加,富含颗粒的断层破碎带从沿离散剪切面的局部变形过渡到整个破碎带层的分布变形,从而促进了这种削弱。在云英岩含量固定的情况下,摩擦特性取决于主要的颗粒相。以方解石为主的混合物比以石英为主的混合物表现出更明显的摩擦减弱,这表明摩擦系数与白云母含量之间存在非线性混合规律。与石英不同的是,这种不同的趋势可能是由于方解石在流体辅助下压力溶解和褶皱发展的有利条件所致。当只有颗粒相混合时,我们观察到石英压入方解石的复杂行为,导致愈合率值高于纯端部混合物的愈合率值。
{"title":"Heterogeneous mineralogical composition and fault behaviour: A systematic study in ternary fault rock compositions","authors":"Roberta Ruggieri ,&nbsp;Giacomo Pozzi ,&nbsp;Giuseppe Volpe ,&nbsp;Francesca Bottazzi ,&nbsp;Marco Brignoli ,&nbsp;Anna Antonia Irene Corradi ,&nbsp;Stefano Mantica ,&nbsp;Lorenzo Osculati ,&nbsp;Stefania Petroselli ,&nbsp;Giorgio Volontè ,&nbsp;Cristiano Collettini","doi":"10.1016/j.tecto.2024.230528","DOIUrl":"10.1016/j.tecto.2024.230528","url":null,"abstract":"<div><div>The heterogeneous mineralogical compositions of fault gouges, formed during fault evolution, influence frictional properties and slip behaviour. While the influence of individual mineral phases on friction has been extensively studied, the impact of varying systematically mineral phases in gouge mixtures on macroscopic frictional behaviour remains unclear. Thus, we performed 34 frictional experiments on fault gouges composed of three representative mineral phases: muscovite (platy phyllosilicate), quartz (granular silicate) and calcite (granular carbonate), known for their markedly distinct frictional properties. Using a biaxial rock deformation apparatus (BRAVA), we performed tests on fault gouges with grain sizes &lt;125 μm under normal stresses of 50–100 MPa, at room temperature and water-saturated conditions. Our data indicate that the mineralogical composition of fault gouges significantly affects frictional strength, healing, and stability with a non-trivial pattern. Increasing the muscovite content leads to a decrease in frictional strength, from 0.62 for pure calcite and 0.56 for pure quartz to 0.33 of pure muscovite, along with reduced frictional healing and a velocity-strengthening behaviour. This weakening is promoted by a transition from localized deformation along discrete shear planes in granular-rich fault gouges to distributed deformation within the entire gouge layer with increasing muscovite content. At fixed muscovite content, frictional properties depend on the dominant granular phase. Calcite-dominated mixtures exhibit more marked frictional weakening rather than quartz-dominated ones, suggesting a non-linear mixing law between friction coefficient and muscovite content. This different trend is likely due to favourable conditions for fluid-assisted pressure-solution of calcite and foliation development, unlike quartz. When only the granular phases are mixed, we observe complex behaviour with the indentation of quartz into calcite, resulting in higher values of healing rates than those of pure end-member mixtures.</div><div>Our findings provide robust insights into microphysical processes strongly dependent on the complex mineralogical compositions usually observed along natural faults.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"891 ","pages":"Article 230528"},"PeriodicalIF":2.7,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142529075","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
Recent and active faulting along the exposed front of the Northern Apennines (Italy): New insights from field and geochronological constraints 北亚平宁山脉(意大利)暴露前沿的近期活动断层:实地考察和地质年代制约因素带来的新启示
IF 2.7 3区 地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2024-10-09 DOI: 10.1016/j.tecto.2024.230517
Thomas Gusmeo , Giacomo Carloni , Gianluca Vignaroli , Luca Martelli , Hsun-Ming Hu , Chuan-Chou Shen , Giulio Viola
Establishing genetic links between active shallow faulting and deep seismogenic sources is challenging, especially in areas where seismogenic faults lack clear and readily interpretable geological evidence at the surface. The architecture of the Pedeapenninic margin of the Northern Apennines (Italy) reflects a regional-scale and complex NE-verging blind thrust system, which is dissected by transpressive/transtensive faults resulting from active NE-SW orogenic compression. The local geological framework is defined by allochthonous ocean-derived units resting atop Pliocene-to-present successions exposed along the Northern Apennines margin and to the NE of it, while the innermost chain sector mostly contains Adria-related units. We present results from field structural-geological investigations to identify and characterize potential active faults along the margin. There, the Pliocene-to-present units are faulted and folded, indicating that tectonic activity is still on-going, thus contributing to the local seismic hazard. Top-to-the NE and SW normal faults are common in the area and deform the Pliocene-to-present succession together with NE-SW strike-slip and transpressional/transtensional faults. Based on field evidence, we define four potentially active thrust segments affecting Middle Pleistocene to Holocene deposits exposed along the margin. Calcite U-Th dating on samples from faults extend the most recent datable tectonic activity back to the Middle Pleistocene. Paleostress analysis from inversion of fault-slip data from the most recent identified striated fault planes constrains a NE-SW shortening direction parallel to the Apennines regional migration direction. A distinct but coaxial extensional stress regime, recorded by structures measured within Plio-Pleistocene formations, was also identified. Our results offer a sound starting point for future investigations aimed at improving our understanding of active and seismogenic faulting in the area, so as to create robust Probabilistic Seismic and Fault Displacement Hazard Assessment (PSHA and PFDHA) models that can implement refined seismic hazard maps benefitting from structural-geological deterministic inputs in addition to the classic seismological constraints.
在活跃的浅层断层和深层震源之间建立遗传联系具有挑战性,尤其是在震源断层在地表缺乏清晰、易于解释的地质证据的地区。北亚平宁山脉(意大利)的佩德亚平宁山脉边缘的结构反映了一个区域规模的复杂东北向盲推系统,该系统被活跃的东北-西南造山运动压缩产生的换位/张性断层所分割。当地的地质框架由同生代的海洋衍生单元所定义,这些单元位于沿亚平宁半岛北部边缘及其东北部出露的上新世至今的岩层之上,而最内侧的岩层链部分则主要包含与亚得里亚海有关的单元。我们介绍了野外构造地质调查的结果,以确定和描述北亚平宁山脉边缘潜在的活动断层。在那里,上新世到现在的单元都有断层和褶皱,表明构造活动仍在继续,从而加剧了当地的地震灾害。该地区常见的是自上而下的 NE 和 SW 正断层,它们与 NE-SW 走向滑动断层和换位/张拉断层一起使上新世至今的岩层发生变形。根据实地证据,我们确定了四个潜在的活动推力段,这些推力段影响着沿边缘出露的中更新世至全新世沉积物。对断层样本进行的方解石 U-Th 测定将可追溯到中更新世的最新构造活动延伸到了中更新世。通过对最新发现的条状断层平面的断层滑动数据进行反演,古应力分析确定了与亚平宁山脉区域迁移方向平行的东北-西南缩短方向。同时还确定了一个独特但同轴的伸展应力机制,该机制由在上新世-更新世地层中测量到的结构记录下来。我们的研究结果为今后的研究提供了一个良好的起点,旨在提高我们对该地区活动断层和地震断层的认识,从而建立稳健的地震和断层位移危害概率评估(PSHA 和 PFDHA)模型,除了传统的地震学约束外,还能利用结构-地质确定性输入来绘制精细的地震危害图。
{"title":"Recent and active faulting along the exposed front of the Northern Apennines (Italy): New insights from field and geochronological constraints","authors":"Thomas Gusmeo ,&nbsp;Giacomo Carloni ,&nbsp;Gianluca Vignaroli ,&nbsp;Luca Martelli ,&nbsp;Hsun-Ming Hu ,&nbsp;Chuan-Chou Shen ,&nbsp;Giulio Viola","doi":"10.1016/j.tecto.2024.230517","DOIUrl":"10.1016/j.tecto.2024.230517","url":null,"abstract":"<div><div>Establishing genetic links between active shallow faulting and deep seismogenic sources is challenging, especially in areas where seismogenic faults lack clear and readily interpretable geological evidence at the surface. The architecture of the Pedeapenninic margin of the Northern Apennines (Italy) reflects a regional-scale and complex NE-verging blind thrust system, which is dissected by transpressive/transtensive faults resulting from active NE-SW orogenic compression. The local geological framework is defined by allochthonous ocean-derived units resting atop Pliocene-to-present successions exposed along the Northern Apennines margin and to the NE of it, while the innermost chain sector mostly contains Adria-related units. We present results from field structural-geological investigations to identify and characterize potential active faults along the margin. There, the Pliocene-to-present units are faulted and folded, indicating that tectonic activity is still on-going, thus contributing to the local seismic hazard. Top-to-the NE and SW normal faults are common in the area and deform the Pliocene-to-present succession together with NE-SW strike-slip and transpressional/transtensional faults. Based on field evidence, we define four potentially active thrust segments affecting Middle Pleistocene to Holocene deposits exposed along the margin. Calcite U-Th dating on samples from faults extend the most recent datable tectonic activity back to the Middle Pleistocene. Paleostress analysis from inversion of fault-slip data from the most recent identified striated fault planes constrains a NE-SW shortening direction parallel to the Apennines regional migration direction. A distinct but coaxial extensional stress regime, recorded by structures measured within Plio-Pleistocene formations, was also identified. Our results offer a sound starting point for future investigations aimed at improving our understanding of active and seismogenic faulting in the area, so as to create robust Probabilistic Seismic and Fault Displacement Hazard Assessment (PSHA and PFDHA) models that can implement refined seismic hazard maps benefitting from structural-geological deterministic inputs in addition to the classic seismological constraints.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"891 ","pages":"Article 230517"},"PeriodicalIF":2.7,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142433753","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
Morphostructural evidence of crustal-scale, active along-strike segmentation of the Umbria-Marche Apennines, Italy 意大利翁布里亚-马尔凯亚平宁山脉地壳尺度活跃沿脉分段的形态构造证据
IF 2.7 3区 地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2024-10-09 DOI: 10.1016/j.tecto.2024.230527
S. Teloni , E. Valente , A. Ascione , S. Mazzoli , P.P. Pierantoni , M.C. Invernizzi
This paper discusses the response of topography and river networks to non-uniform lithology and tectonic forcing in the Umbria-Marche sector of the Apennines fold and thrust belt. We ruled out the role of variable erosion of rock types and interpret channel steepness data in terms of rock uplift, discovering a southward increase in the total amount of uplift. Such a trend appears as the large-scale response to uneven vertical motions of different sectors of the mountain ridge and foothills. The general coincidence between sector boundaries and transversal, NE-SW striking faults mapped by seismic interpretation in the outer zone of the fold and thrust belt, suggests that such faults extend to the SW, beneath the allochthonous thrust sheets of the mountainous area. Therefore, it may be inferred that such transversal faults represent long-lived, deeply rooted basement structures compartmentalizing both the axial and the outer zones of the fold and thrust belt. We suggest that differential uplift was essentially controlled by variable amounts of basement thrust displacement characterizing the compartmentalized belt. This interpretation deviates from a more conventional view that uplift of the central Apennines, particularly prominent in the south, is dynamically supported. Our results, besides shedding new light into the active tectonic behavior of a large portion of the Italian peninsula, also provide general insights into the surface response to the differential behavior of crustal blocks produced by along-strike segmentation of active mountain belts.
本文讨论了亚平宁褶皱和推力带翁布里亚-马尔凯地区的地形和河网对不均匀岩性和构造作用的响应。我们排除了岩石类型多变侵蚀的作用,并从岩石隆起的角度解释了河道陡度数据,发现隆起总量向南增加。这种趋势是山脊和山麓不同地段不均匀垂直运动的大规模反应。褶皱和推力带外围地带的地震解释所绘制的横向、东北-西南走向断层与扇形边界之间的普遍吻合表明,此类断层延伸至西南部,位于山区的同生推力片之下。因此,可以推断这种横向断层代表了长期存在的、根深蒂固的基底结构,将褶皱与推力带的轴向和外侧区域分隔开来。我们认为,差异隆升主要受控于不同数量的基底推力位移,这也是分隔带的特征。这一解释偏离了亚平宁半岛中部(尤其是南部)的隆升是由动力支持的这一传统观点。我们的研究结果除了为意大利半岛大部分地区的活动构造行为提供了新的启示之外,还对活动山带沿走向分段所产生的地壳块体不同行为的地表反应提供了一般的见解。
{"title":"Morphostructural evidence of crustal-scale, active along-strike segmentation of the Umbria-Marche Apennines, Italy","authors":"S. Teloni ,&nbsp;E. Valente ,&nbsp;A. Ascione ,&nbsp;S. Mazzoli ,&nbsp;P.P. Pierantoni ,&nbsp;M.C. Invernizzi","doi":"10.1016/j.tecto.2024.230527","DOIUrl":"10.1016/j.tecto.2024.230527","url":null,"abstract":"<div><div>This paper discusses the response of topography and river networks to non-uniform lithology and tectonic forcing in the Umbria-Marche sector of the Apennines fold and thrust belt. We ruled out the role of variable erosion of rock types and interpret channel steepness data in terms of rock uplift, discovering a southward increase in the total amount of uplift. Such a trend appears as the large-scale response to uneven vertical motions of different sectors of the mountain ridge and foothills. The general coincidence between sector boundaries and transversal, NE-SW striking faults mapped by seismic interpretation in the outer zone of the fold and thrust belt, suggests that such faults extend to the SW, beneath the allochthonous thrust sheets of the mountainous area. Therefore, it may be inferred that such transversal faults represent long-lived, deeply rooted basement structures compartmentalizing both the axial and the outer zones of the fold and thrust belt. We suggest that differential uplift was essentially controlled by variable amounts of basement thrust displacement characterizing the compartmentalized belt. This interpretation deviates from a more conventional view that uplift of the central Apennines, particularly prominent in the south, is dynamically supported. Our results, besides shedding new light into the active tectonic behavior of a large portion of the Italian peninsula, also provide general insights into the surface response to the differential behavior of crustal blocks produced by along-strike segmentation of active mountain belts.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"891 ","pages":"Article 230527"},"PeriodicalIF":2.7,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142418536","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
Crustal and uppermost mantle S-velocity structure of the Seoul metropolitan area on the Korean Peninsula from Helmholtz tomography 通过亥姆霍兹断层扫描研究朝鲜半岛首尔都市圈的地壳和最上层地幔 S-速度结构
IF 2.7 3区 地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2024-10-05 DOI: 10.1016/j.tecto.2024.230518
Seungwoo Park , Sung-Joon Chang , Junhyung Lee , Dongchan Chung , Byeongwoo Kim , Seongjun Park , Tae-Kyung Hong
The Seoul metropolitan area, the most densely populated part of the Korean Peninsula, features complex subsurface structures and seismogenic faults, though their characteristics remain ambiguous due to low seismicity and limitations in fault investigation. High-resolution velocity models can provide constraints for identifying subsurface faults by detecting elongated low-velocity anomalies along fault zones. Recently, a dense seismic network was deployed in this area, facilitating the use of Helmholtz tomography, an array-based method that accounts for finite-frequency effects. Utilizing Helmholtz tomography, we obtained a high-resolution S-wave velocity model down to a depth of 50 km with waveform data recorded at 74 broadband seismic stations. We found that a linear low-velocity anomaly along the Pocheon fault extends to the uppermost mantle, with an increasing width with depth. In contrast, the Dongducheon fault, which traverses Seoul from north to south, is not well imaged, indicating its current weak activity. Another linear low-velocity anomaly extends southwest through Seoul from northern Seoul, potentially representing the extension of the Pocheon fault based on similar strike and dip directions. Additionally, a large lateral low-velocity anomaly is identified in the lower crust beneath the northern part of the Seoul metropolitan area, interpreted as a ductile décollement, connected with the Pocheon, Wangsukcheon, and possibly Gyeonggang faults. This study successfully identified the extensions and orientations of subsurface faults beneath the Seoul metropolitan area down to the uppermost mantle, which is critical for seismic hazard predictions and earthquake simulations in this highly populated area.
首尔大都市区是朝鲜半岛人口最稠密的地区,具有复杂的地下结构和地震断层,但由于地震发生率低和断层调查的局限性,其特征仍然模糊不清。高分辨率速度模型可以通过探测沿断层带拉长的低速度异常,为识别地下断层提供约束条件。最近,在这一地区部署了密集的地震网络,为使用亥姆霍兹层析成像法提供了便利,这是一种基于阵列的方法,考虑到了有限频率效应。利用亥姆霍兹层析成像法,我们利用 74 个宽带地震台站记录的波形数据,获得了深度达 50 千米的高分辨率 S 波速度模型。我们发现,波川断层沿线的线性低速度异常一直延伸到最上层地幔,宽度随深度增加而增大。相比之下,从北到南横穿首尔的东都川断层没有得到很好的成像,这表明其目前的活动性较弱。另一个线性低速异常从首尔北部向西南延伸穿过首尔,根据相似的走向和倾角方向,可能代表了抱川断层的延伸。此外,在首尔市区北部地壳下部还发现了一个大的横向低速异常,被解释为与浦川断层、王水川断层以及可能的京江断层相连的韧性断层。这项研究成功地确定了首尔市区地下直至最上地幔的地下断层的延伸和走向,这对这一人口密集地区的地震灾害预测和地震模拟至关重要。
{"title":"Crustal and uppermost mantle S-velocity structure of the Seoul metropolitan area on the Korean Peninsula from Helmholtz tomography","authors":"Seungwoo Park ,&nbsp;Sung-Joon Chang ,&nbsp;Junhyung Lee ,&nbsp;Dongchan Chung ,&nbsp;Byeongwoo Kim ,&nbsp;Seongjun Park ,&nbsp;Tae-Kyung Hong","doi":"10.1016/j.tecto.2024.230518","DOIUrl":"10.1016/j.tecto.2024.230518","url":null,"abstract":"<div><div>The Seoul metropolitan area, the most densely populated part of the Korean Peninsula, features complex subsurface structures and seismogenic faults, though their characteristics remain ambiguous due to low seismicity and limitations in fault investigation. High-resolution velocity models can provide constraints for identifying subsurface faults by detecting elongated low-velocity anomalies along fault zones. Recently, a dense seismic network was deployed in this area, facilitating the use of Helmholtz tomography, an array-based method that accounts for finite-frequency effects. Utilizing Helmholtz tomography, we obtained a high-resolution S-wave velocity model down to a depth of 50 km with waveform data recorded at 74 broadband seismic stations. We found that a linear low-velocity anomaly along the Pocheon fault extends to the uppermost mantle, with an increasing width with depth. In contrast, the Dongducheon fault, which traverses Seoul from north to south, is not well imaged, indicating its current weak activity. Another linear low-velocity anomaly extends southwest through Seoul from northern Seoul, potentially representing the extension of the Pocheon fault based on similar strike and dip directions. Additionally, a large lateral low-velocity anomaly is identified in the lower crust beneath the northern part of the Seoul metropolitan area, interpreted as a ductile décollement, connected with the Pocheon, Wangsukcheon, and possibly Gyeonggang faults. This study successfully identified the extensions and orientations of subsurface faults beneath the Seoul metropolitan area down to the uppermost mantle, which is critical for seismic hazard predictions and earthquake simulations in this highly populated area.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"891 ","pages":"Article 230518"},"PeriodicalIF":2.7,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142418528","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
Variscan basement tectonics and Alpine shear zones in the external Balkanides: Structural data from the Vezhen Massif, Central Stara Planina Mts., Bulgaria 巴尔干山脉外部的变质基底构造和阿尔卑斯剪切带:保加利亚斯塔拉普兰纳山脉中部维珍山丘的构造数据
IF 2.7 3区 地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2024-10-03 DOI: 10.1016/j.tecto.2024.230515
Anna Lazarova , Ianko Gerdjikov
The Alpine Balkanides in Bulgaria are developed over Variscan orogenic fragments, which are variously affected by late-stage thick-skinned thrust tectonics. Often, these fragments hold both Variscan and Alpine structural records. А key area to shed light on important aspects of the tectonic evolution of the external parts of the Alpine Balkanide orogen is the Vezhen Massif in the Central Stara Planina Mountains. Although it is built exclusively of Paleozoic crystalline rocks, its structure was long considered as an example of intense mid Eocene to early Oligocene (Late Alpine) shortening. Detailed fieldwork in the area shows a more complicated tectonic framework and provides evidence of a polyphase structural evolution, involving an important stage of Variscan metamorphism and deformation and two stages of north-vergent Alpine shortening. The Stargel-Boluvanya Tectonic Zone that affects the western Vezhen Massif is one of the most important Variscan structures in the Balkan fold-and-thrust belt. Structural data indicate that the metamorphic basement records initial top-to-north thrusting, followed by further shortening, which led to folding and localized strike-slip deformation. The Variscan syn-metamorphic fabric is cross-cut by several post-kinematic igneous bodies of late Carboniferous to Permian ages. The tectonic history continues with a development of a network of greenschist facies north-vergent mylonitic zones for which an Early Alpine (post-late Permian but pre-Late Cretaceous) age is assumed. Late Alpine north-vergent thrusting is evident only on the eastern and northern flanks of the Vezhen Massif. In a broad structural context, the documented record in the basement rocks of the Vezhen Massif is comparable with those of the external massifs of the Alps and Iberia.
保加利亚的阿尔卑斯山巴尔干山脉发育在瓦里斯山造山运动片段之上,这些片段受到晚期厚皮推覆构造的不同影响。通常情况下,这些碎块同时保留了瓦里斯山和阿尔卑斯山的构造记录。Alpine Balkanide 造山带外部构造演化的重要方面的一个关键地区是位于 Stara Planina 山脉中部的 Vezhen 地块。虽然它完全由古生代结晶岩构成,但其结构长期以来一直被认为是始新世中期到渐新世早期(阿尔卑斯山晚期)强烈缩短的典范。在该地区进行的详细实地考察显示了一个更为复杂的构造框架,并提供了多阶段构造演化的证据,其中包括一个重要的瓦里斯坎变质和变形阶段,以及两个北伸的阿尔卑斯山缩短阶段。影响维珍山丘西部的斯塔盖尔-波卢万亚构造带是巴尔干褶皱推覆带中最重要的瓦里斯山构造之一。构造数据表明,变质基底记录了最初的自上而下的推力,随后进一步缩短,导致褶皱和局部走向滑动变形。瓦里斯坎期的同步变质构造被几个石炭纪晚期至二叠纪的后激变火成岩体交叉切割。构造历史继续发展,形成了绿泥石面北向隆起的熔岩带网络,假定其年代为阿尔卑斯山早期(二叠纪晚期之后,白垩纪晚期之前)。阿尔卑斯山晚期的北向推力仅在卫镇山丘的东侧和北侧较为明显。从广义的构造角度来看,织金山丘基底岩石的文献记录与阿尔卑斯山和伊比利亚山丘的外部记录相当。
{"title":"Variscan basement tectonics and Alpine shear zones in the external Balkanides: Structural data from the Vezhen Massif, Central Stara Planina Mts., Bulgaria","authors":"Anna Lazarova ,&nbsp;Ianko Gerdjikov","doi":"10.1016/j.tecto.2024.230515","DOIUrl":"10.1016/j.tecto.2024.230515","url":null,"abstract":"<div><div>The Alpine Balkanides in Bulgaria are developed over Variscan orogenic fragments, which are variously affected by late-stage thick-skinned thrust tectonics. Often, these fragments hold both Variscan and Alpine structural records. А key area to shed light on important aspects of the tectonic evolution of the external parts of the Alpine Balkanide orogen is the Vezhen Massif in the Central Stara Planina Mountains. Although it is built exclusively of Paleozoic crystalline rocks, its structure was long considered as an example of intense mid Eocene to early Oligocene (Late Alpine) shortening. Detailed fieldwork in the area shows a more complicated tectonic framework and provides evidence of a polyphase structural evolution, involving an important stage of Variscan metamorphism and deformation and two stages of north-vergent Alpine shortening. The Stargel-Boluvanya Tectonic Zone that affects the western Vezhen Massif is one of the most important Variscan structures in the Balkan fold-and-thrust belt. Structural data indicate that the metamorphic basement records initial top-to-north thrusting, followed by further shortening, which led to folding and localized strike-slip deformation. The Variscan <em>syn</em>-metamorphic fabric is cross-cut by several post-kinematic igneous bodies of late Carboniferous to Permian ages. The tectonic history continues with a development of a network of greenschist facies north-vergent mylonitic zones for which an Early Alpine (post-late Permian but pre-Late Cretaceous) age is assumed. Late Alpine north-vergent thrusting is evident only on the eastern and northern flanks of the Vezhen Massif. In a broad structural context, the documented record in the basement rocks of the Vezhen Massif is comparable with those of the external massifs of the Alps and Iberia.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"891 ","pages":"Article 230515"},"PeriodicalIF":2.7,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142433754","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
Constraining the slip history of the Katschberg normal fault (Eastern Tauern Window) by thermo-kinematic modeling: Implications for the tectonic evolution of the Eastern European Alps in the late Cenozoic 通过热运动学建模确定 Katschberg 正断层(东陶恩窗)的滑动历史:对晚新生代东欧阿尔卑斯山构造演化的影响
IF 2.7 3区 地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2024-09-26 DOI: 10.1016/j.tecto.2024.230514
Reinhard Wolff , Andreas Wölfler , Andrea Hampel , István Dunkl
The Katschberg normal fault borders the Tauern Window to the east and played a crucial role during Miocene lateral tectonic extrusion in the Eastern European Alps. In this study, we present new cooling ages from low-temperature thermochronology as well as thermo-kinematic models, which constrain the exhumation history of the Penninic units in the footwall of the Katschberg normal fault and its slip history. Zircon and apatite fission track and apatite (U–Th)/He ages from footwall units range from 16.0 ± 1.9 Ma to 12.8 ± 1.4 Ma, 10.4 ± 1.8 Ma to 7.9 ± 1.3 Ma and 8.2 ± 0.8 Ma to 3.9 ± 0.4 Ma, respectively. Thermo-kinematic modeling indicates that the Katschberg normal fault was active between 21.1 ± 1.8 Ma and 12.2 ± 1.3 Ma and accommodated 27 ± 6 km of crustal extension at a total rate of 3.5 ± 0.3 km/Myr. After the end of normal faulting, exhumation continued with a rate of 0.21 ± 0.06 km/Myr until 2.0 ± 0.5 Ma and with a rate of 0.84 ± 0.08 km/Myr until present. A comparison with another Miocene low-angle normal fault in the Eastern Alps – the Brenner fault – reveals that the amount of extension accommodated by these faults decreases from west to east, which is consistent with an eastward decrease in N-S shortening. Therefore, Miocene deformation is greatest in the western Tauern Window near the Brenner normal fault where shortening in front of the Adriatic Indenter is at its maximum.
卡茨贝格正断层在东面与陶恩窗接壤,在东欧阿尔卑斯山中新世横向构造挤压过程中发挥了至关重要的作用。在这项研究中,我们通过低温热震学以及热运动学模型,提出了新的冷却年龄,从而对卡茨贝格正断层脚墙彭尼尼单元的出露历史及其滑动历史进行了约束。脚墙单元的锆石和磷灰石裂变轨迹和磷灰石(U-Th)/He年龄分别为 16.0 ± 1.9 Ma 至 12.8 ± 1.4 Ma、10.4 ± 1.8 Ma 至 7.9 ± 1.3 Ma 和 8.2 ± 0.8 Ma 至 3.9 ± 0.4 Ma。热运动学模型显示,卡茨贝格正断层在 21.1 ± 1.8 Ma 至 12.2 ± 1.3 Ma 期间处于活跃状态,并以 3.5 ± 0.3 km/Myr 的总速率容纳了 27 ± 6 km 的地壳延伸。正断层结束后,地壳继续以0.21 ± 0.06 km/Myr的速度隆起,直到2.0 ± 0.5 Ma,直到现在,隆起速度为0.84 ± 0.08 km/Myr。与东阿尔卑斯山的另一个中新世低角度正断层--布伦纳断层--的比较显示,这些断层所容纳的延伸量自西向东递减,这与北南缩短的东向递减相一致。因此,在布伦纳正断层附近的陶恩窗西部,中新世时期的变形最大,那里亚得里亚海肠前的缩短达到最大程度。
{"title":"Constraining the slip history of the Katschberg normal fault (Eastern Tauern Window) by thermo-kinematic modeling: Implications for the tectonic evolution of the Eastern European Alps in the late Cenozoic","authors":"Reinhard Wolff ,&nbsp;Andreas Wölfler ,&nbsp;Andrea Hampel ,&nbsp;István Dunkl","doi":"10.1016/j.tecto.2024.230514","DOIUrl":"10.1016/j.tecto.2024.230514","url":null,"abstract":"<div><div>The Katschberg normal fault borders the Tauern Window to the east and played a crucial role during Miocene lateral tectonic extrusion in the Eastern European Alps. In this study, we present new cooling ages from low-temperature thermochronology as well as thermo-kinematic models, which constrain the exhumation history of the Penninic units in the footwall of the Katschberg normal fault and its slip history. Zircon and apatite fission track and apatite (U–Th)/He ages from footwall units range from 16.0 ± 1.9 Ma to 12.8 ± 1.4 Ma, 10.4 ± 1.8 Ma to 7.9 ± 1.3 Ma and 8.2 ± 0.8 Ma to 3.9 ± 0.4 Ma, respectively. Thermo-kinematic modeling indicates that the Katschberg normal fault was active between 21.1 ± 1.8 Ma and 12.2 ± 1.3 Ma and accommodated 27 ± 6 km of crustal extension at a total rate of 3.5 ± 0.3 km/Myr. After the end of normal faulting, exhumation continued with a rate of 0.21 ± 0.06 km/Myr until 2.0 ± 0.5 Ma and with a rate of 0.84 ± 0.08 km/Myr until present. A comparison with another Miocene low-angle normal fault in the Eastern Alps – the Brenner fault – reveals that the amount of extension accommodated by these faults decreases from west to east, which is consistent with an eastward decrease in N-S shortening. Therefore, Miocene deformation is greatest in the western Tauern Window near the Brenner normal fault where shortening in front of the Adriatic Indenter is at its maximum.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"890 ","pages":"Article 230514"},"PeriodicalIF":2.7,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142326466","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
Stress heterogeneity in the eastern Tibetan Plateau and implications for the present-day plateau expansion 青藏高原东部的应力异质性及其对当今高原扩张的影响
IF 2.7 3区 地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2024-09-24 DOI: 10.1016/j.tecto.2024.230513
Haoqing Liu , Yujiang Li , Cheng Yang , Lianwang Chen
The eastward expansion of the Tibetan Plateau has resulted in different earthquake types in the eastern Tibetan Plateau, but the mechanism remains unclear. Here, we construct a three-dimensional visco-elastoplastic finite element model considering the topography to investigate the influence of fault geometry and rheological heterogeneity on stress fields. In our best-fitting model, the minimum principal stress is nearly vertical around the southern Huya fault zone, which is adjacent to the Longmen Shan fault zone, due to the significant mid-lowerWE crust lateral rheological heterogeneity, and the thrust stress regime accounts for the reverse fault and thrust-dominated earthquakes. In this scenario, the eastward horizontal motion of the mid-lower crust is obstructed and facilitates thrust faulting, suggesting the limited eastward expansion of the Tibetan Plateau. In contrast, the northern Huya fault zone, one of the terminal branches of the East Kunlun fault, accommodates the continuous eastward extrusion of the East Kunlun fault, where the stress regime under a more homogenized crust favors the strike-slip faulting process, along with the dominant strike-slip earthquakes. Moreover, the best-fitting of stress regime explains the thrust-dominated 2008 Ms. 8.0 Wenchuan and 2013 Ms. 7.0 Lushan earthquakes on the Longmen Shan fault zone. Combining geophysical and geodetic observations and model analyses, we propose that the hybrid deformation mode in the eastern Tibetan Plateau is accommodated by upper crustal shear and thrusting deformation and mid-lower crustal thickening driven by the gravitational potential energy gradient. Our results elucidate the mechanism for differences in strong historical earthquakes and, more importantly, isolate the effect of fault geometry from those of heterogeneous viscosity on crustal deformation and stress heterogeneity in the eastern Tibetan Plateau.
青藏高原东扩导致青藏高原东部出现了不同类型的地震,但其机理尚不清楚。在此,我们构建了一个考虑地形的三维粘弹性有限元模型,以研究断层几何形状和流变异质性对应力场的影响。在我们的最佳拟合模型中,由于中低纬地壳侧向流变异质性显著,与龙门山断裂带相邻的南虎牙断裂带附近的最小主应力近乎垂直,而反向断层和推力为主的地震则由推力应力机制引起。在这种情况下,中下地壳向东的水平运动受阻,有利于推力断层的形成,表明青藏高原向东扩展有限。与此相反,东昆仑断裂的末端分支之一--虎牙断裂带北部,容纳了东昆仑断裂的持续向东挤压,在地壳更加均匀的情况下,应力机制有利于走向滑动断层的形成过程,并伴随着主要的走向滑动地震。此外,应力机制的最佳拟合解释了龙门山断裂带上以推力为主的 2008 年汶川 8.0 级地震和 2013 年芦山 7.0 级地震。结合地球物理和大地测量观测结果以及模型分析,我们提出青藏高原东部的混合变形模式是由上地壳剪切变形和推覆变形以及重力势能梯度驱动的中下地壳增厚所决定的。我们的研究结果阐明了历史强震的差异机制,更重要的是,将断层几何与异质粘度对青藏高原东部地壳变形和应力异质性的影响分离开来。
{"title":"Stress heterogeneity in the eastern Tibetan Plateau and implications for the present-day plateau expansion","authors":"Haoqing Liu ,&nbsp;Yujiang Li ,&nbsp;Cheng Yang ,&nbsp;Lianwang Chen","doi":"10.1016/j.tecto.2024.230513","DOIUrl":"10.1016/j.tecto.2024.230513","url":null,"abstract":"<div><div>The eastward expansion of the Tibetan Plateau has resulted in different earthquake types in the eastern Tibetan Plateau, but the mechanism remains unclear. Here, we construct a three-dimensional visco-elastoplastic finite element model considering the topography to investigate the influence of fault geometry and rheological heterogeneity on stress fields. In our best-fitting model, the minimum principal stress is nearly vertical around the southern Huya fault zone, which is adjacent to the Longmen Shan fault zone, due to the significant mid-lowerWE crust lateral rheological heterogeneity, and the thrust stress regime accounts for the reverse fault and thrust-dominated earthquakes. In this scenario, the eastward horizontal motion of the mid-lower crust is obstructed and facilitates thrust faulting, suggesting the limited eastward expansion of the Tibetan Plateau. In contrast, the northern Huya fault zone, one of the terminal branches of the East Kunlun fault, accommodates the continuous eastward extrusion of the East Kunlun fault, where the stress regime under a more homogenized crust favors the strike-slip faulting process, along with the dominant strike-slip earthquakes. Moreover, the best-fitting of stress regime explains the thrust-dominated 2008 Ms. 8.0 Wenchuan and 2013 Ms. 7.0 Lushan earthquakes on the Longmen Shan fault zone. Combining geophysical and geodetic observations and model analyses, we propose that the hybrid deformation mode in the eastern Tibetan Plateau is accommodated by upper crustal shear and thrusting deformation and mid-lower crustal thickening driven by the gravitational potential energy gradient. Our results elucidate the mechanism for differences in strong historical earthquakes and, more importantly, isolate the effect of fault geometry from those of heterogeneous viscosity on crustal deformation and stress heterogeneity in the eastern Tibetan Plateau.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"890 ","pages":"Article 230513"},"PeriodicalIF":2.7,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142329780","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
Using contrasts in horizontal P-wave reflectivity to map the base of the continental lithosphere: Results for the central and eastern U.S. 利用水平 P 波反射率的对比来绘制大陆岩石圈的底部:美国中部和东部的研究结果
IF 2.7 3区 地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2024-09-23 DOI: 10.1016/j.tecto.2024.230512
Laura E. Hanawalt , Michael P. Cuilik , Robert B. Hawman
Vertical-incidence seismic reflection profiles generated from global phases for 16 earthquakes recorded by stations of the Transportable Array (TA) show distinctive patterns of P-wave reflectivity in the uppermost mantle beneath the central and eastern United States. The overall distribution of reflections identified objectively using the sign test statistic applied to bootstrapped stacks is consistent with a westward increase in depth of the lithosphere-asthenosphere boundary (LAB) from roughly 110 to 250 km that is marked within the lower lithosphere by piecewise continuous segments of elevated horizontal P-wave reflectivity. For some profiles, the onsets of zones of increased reflectivity closely match depths corresponding to the maximum negative S-wave velocity gradients found by surface-wave tomography, suggesting that P-wave reflectivity can be used to help characterize properties of the lower lithosphere. We suggest that the vertical change in horizontal reflectivity straddles the lithosphere-asthenosphere transition, encompassing a broad zone of layering caused by increased strain in the lower lithosphere as well as drag-induced flow in the asthenosphere. Some of the lines also show waveforms that fall within the depth range of arrivals identified as midlithospheric discontinuities (MLDs) in overlapping Sp receiver-function profiles. The reflection waveforms observed in the TA lines are mostly multicyclic with a mix of polarities indicating a layered transition, consistent with previous observations and model studies that show the breakup of single Sp waveforms into a series of less prominent, shorter-period P-wave reflections as the dominant frequency of incident energy is increased.
由可移动阵列(TA)台站记录的 16 次地震的全球相位生成的垂直入射地震反射剖面显示了美国中部和东部地幔最上层 P 波反射率的独特模式。使用符号检验统计量对自引导叠加数据进行客观识别后发现,反射的总体分布与岩石圈-岩石圈边界(LAB)深度从大约 110 千米向西增加到 250 千米相一致,在岩石圈下部以水平 P 波反射率升高的片断连续段为标志。在某些剖面上,反射率增高区的起点与地表波层析成像发现的最大负 S 波速度梯度的相应深度非常吻合,这表明 P 波反射率可用于帮助描述下岩石圈的特性。我们认为,水平反射率的垂直变化跨越了岩石圈-干流层的过渡,包含了一个广泛的分层区,该分层区是由下岩石圈应变增加以及干流层阻力引起的流动造成的。其中一些线路还显示出波形,这些波形位于重叠 Sp 接收器函数剖面中被确定为岩石圈中层不连续面(MLD)的到达深度范围内。在 TA 线中观测到的反射波形大多是多周期的,极性混杂,表明出现了分层过渡,这与以前的观测和模型研究相一致,后者表明随着入射能量主导频率的增加,单个 Sp 波形会分解为一系列不那么突出、周期较短的 P 波反射。
{"title":"Using contrasts in horizontal P-wave reflectivity to map the base of the continental lithosphere: Results for the central and eastern U.S.","authors":"Laura E. Hanawalt ,&nbsp;Michael P. Cuilik ,&nbsp;Robert B. Hawman","doi":"10.1016/j.tecto.2024.230512","DOIUrl":"10.1016/j.tecto.2024.230512","url":null,"abstract":"<div><div>Vertical-incidence seismic reflection profiles generated from global phases for 16 earthquakes recorded by stations of the Transportable Array (TA) show distinctive patterns of P-wave reflectivity in the uppermost mantle beneath the central and eastern United States. The overall distribution of reflections identified objectively using the sign test statistic applied to bootstrapped stacks is consistent with a westward increase in depth of the lithosphere-asthenosphere boundary (LAB) from roughly 110 to 250 km that is marked within the lower lithosphere by piecewise continuous segments of elevated horizontal P-wave reflectivity. For some profiles, the onsets of zones of increased reflectivity closely match depths corresponding to the maximum negative S-wave velocity gradients found by surface-wave tomography, suggesting that P-wave reflectivity can be used to help characterize properties of the lower lithosphere. We suggest that the vertical change in horizontal reflectivity straddles the lithosphere-asthenosphere transition, encompassing a broad zone of layering caused by increased strain in the lower lithosphere as well as drag-induced flow in the asthenosphere. Some of the lines also show waveforms that fall within the depth range of arrivals identified as midlithospheric discontinuities (MLDs) in overlapping Sp receiver-function profiles. The reflection waveforms observed in the TA lines are mostly multicyclic with a mix of polarities indicating a layered transition, consistent with previous observations and model studies that show the breakup of single Sp waveforms into a series of less prominent, shorter-period P-wave reflections as the dominant frequency of incident energy is increased.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"891 ","pages":"Article 230512"},"PeriodicalIF":2.7,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142528999","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
Seismic structure of Iceland revealed by ambient noise Rayleigh wave tomography 环境噪声瑞利波层析成像揭示冰岛地震结构
IF 2.7 3区 地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS Pub Date : 2024-09-23 DOI: 10.1016/j.tecto.2024.230511
Sen Zhang , Juqing Chen , Lei Pan , Zhengbo Li , Xiaofei Chen
As it is an ideal location for studying plume–ridge interactions, a clear image of the Icelandic upper mantle structure is necessary. We collect continuous seismic records from 164 stations and extract Rayleigh wave dispersion curves via the frequency-Bessel (F-J) transform method. Based on ambient noise tomography, we provide a new shear-wave velocity model of the Icelandic crust and uppermost mantle, extending to a depth of 120 km. The model is validated by the waveform simulation method and reveals extensive crustal low-velocity zones (LVZs) across both the neovolcanic and nonvolcanic zones of Iceland. These crustal LVZs may be attributed to elevated temperatures, partial melting, and lithological variations. A distinct LVZ beneath a depth of 60 km, mainly on the North American Plate, may correspond to Icelandic plume material. Additionally, hot plume material may be delivered to the crust through low-velocity conduits beneath the spreading mid-ocean ridge. There is a clear contrast between the uppermost mantle low-velocity zones (UMLVZs) in the western region and the uppermost mantle high-velocity zones in the eastern region, which may indicate asymmetric tectonic plates on both sides of the mid-ocean ridge. This asymmetry may be attributed to the multiple eastward jumps of the ridge systems. The eastern high-velocity body, meaning a cooler uppermost mantle than that of the western region, may act as a barrier to obstruct the eastward plume flow. Under plume–ridge interactions, plume material can affect crustal accretion and feed volcanic activity on the surface along the spreading Mid-Atlantic Ridge.
由于冰岛是研究羽桥相互作用的理想地点,因此有必要获得冰岛上地幔结构的清晰图像。我们收集了 164 个台站的连续地震记录,并通过频率-贝塞尔(F-J)变换方法提取了瑞利波频散曲线。在环境噪声层析成像法的基础上,我们提供了冰岛地壳和最上层地幔的新剪切波速度模型,该模型延伸至 120 千米深处。该模型通过波形模拟方法进行了验证,并揭示了冰岛新火山带和非火山带广泛的地壳低速区(LVZ)。这些地壳低速区可归因于温度升高、部分熔化和岩性变化。主要位于北美板块的 60 千米深度以下的明显低变质带可能与冰岛羽流物质相对应。此外,热羽流物质可能通过扩张的大洋中脊下方的低速导管输送到地壳。西部地区的最上层地幔低速区与东部地区的最上层地幔高速区之间存在明显的对比,这可能表明大洋中脊两侧的构造板块不对称。这种不对称可能是由于海岭系统多次向东跃迁造成的。东部高速体意味着最上层地幔比西部地区的地幔温度低,可能成为阻碍羽流向东流动的屏障。在羽流-海脊相互作用下,羽流物质会影响地壳增生,并为沿大西洋中脊扩张的地表火山活动提供能量。
{"title":"Seismic structure of Iceland revealed by ambient noise Rayleigh wave tomography","authors":"Sen Zhang ,&nbsp;Juqing Chen ,&nbsp;Lei Pan ,&nbsp;Zhengbo Li ,&nbsp;Xiaofei Chen","doi":"10.1016/j.tecto.2024.230511","DOIUrl":"10.1016/j.tecto.2024.230511","url":null,"abstract":"<div><div>As it is an ideal location for studying plume–ridge interactions, a clear image of the Icelandic upper mantle structure is necessary. We collect continuous seismic records from 164 stations and extract Rayleigh wave dispersion curves via the frequency-Bessel (F-J) transform method. Based on ambient noise tomography, we provide a new shear-wave velocity model of the Icelandic crust and uppermost mantle, extending to a depth of 120 km. The model is validated by the waveform simulation method and reveals extensive crustal low-velocity zones (LVZs) across both the neovolcanic and nonvolcanic zones of Iceland. These crustal LVZs may be attributed to elevated temperatures, partial melting, and lithological variations. A distinct LVZ beneath a depth of 60 km, mainly on the North American Plate, may correspond to Icelandic plume material. Additionally, hot plume material may be delivered to the crust through low-velocity conduits beneath the spreading mid-ocean ridge. There is a clear contrast between the uppermost mantle low-velocity zones (UMLVZs) in the western region and the uppermost mantle high-velocity zones in the eastern region, which may indicate asymmetric tectonic plates on both sides of the mid-ocean ridge. This asymmetry may be attributed to the multiple eastward jumps of the ridge systems. The eastern high-velocity body, meaning a cooler uppermost mantle than that of the western region, may act as a barrier to obstruct the eastward plume flow. Under plume–ridge interactions, plume material can affect crustal accretion and feed volcanic activity on the surface along the spreading Mid-Atlantic Ridge.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"891 ","pages":"Article 230511"},"PeriodicalIF":2.7,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142418588","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
期刊
Tectonophysics
全部 Acc. Chem. Res. ACS Applied Bio Materials ACS Appl. Electron. Mater. ACS Appl. Energy Mater. ACS Appl. Mater. Interfaces ACS Appl. Nano Mater. ACS Appl. Polym. Mater. ACS BIOMATER-SCI ENG ACS Catal. ACS Cent. Sci. ACS Chem. Biol. ACS Chemical Health & Safety ACS Chem. Neurosci. ACS Comb. Sci. ACS Earth Space Chem. ACS Energy Lett. ACS Infect. Dis. ACS Macro Lett. ACS Mater. Lett. ACS Med. Chem. Lett. ACS Nano ACS Omega ACS Photonics ACS Sens. ACS Sustainable Chem. Eng. ACS Synth. Biol. Anal. Chem. BIOCHEMISTRY-US Bioconjugate Chem. BIOMACROMOLECULES Chem. Res. Toxicol. Chem. Rev. Chem. Mater. CRYST GROWTH DES ENERG FUEL Environ. Sci. Technol. Environ. Sci. Technol. Lett. Eur. J. Inorg. Chem. IND ENG CHEM RES Inorg. Chem. J. Agric. Food. Chem. J. Chem. Eng. Data J. Chem. Educ. J. Chem. Inf. Model. J. Chem. Theory Comput. J. Med. Chem. J. Nat. Prod. J PROTEOME RES J. Am. Chem. Soc. LANGMUIR MACROMOLECULES Mol. Pharmaceutics Nano Lett. Org. Lett. ORG PROCESS RES DEV ORGANOMETALLICS J. Org. Chem. J. Phys. Chem. J. Phys. Chem. A J. Phys. Chem. B J. Phys. Chem. C J. Phys. Chem. Lett. Analyst Anal. Methods Biomater. Sci. Catal. Sci. Technol. Chem. Commun. Chem. Soc. Rev. CHEM EDUC RES PRACT CRYSTENGCOMM Dalton Trans. Energy Environ. Sci. ENVIRON SCI-NANO ENVIRON SCI-PROC IMP ENVIRON SCI-WAT RES Faraday Discuss. Food Funct. Green Chem. Inorg. Chem. Front. Integr. Biol. J. Anal. At. Spectrom. J. Mater. Chem. A J. Mater. Chem. B J. Mater. Chem. C Lab Chip Mater. Chem. Front. Mater. Horiz. MEDCHEMCOMM Metallomics Mol. Biosyst. Mol. Syst. Des. Eng. Nanoscale Nanoscale Horiz. Nat. Prod. Rep. New J. Chem. Org. Biomol. Chem. Org. Chem. Front. PHOTOCH PHOTOBIO SCI PCCP Polym. Chem.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 联系我们:info@booksci.cn
Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。
Copyright © 2023 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1