Tectonophysics最新文献_第8页

Prolonged early cretaceous crustal extension in the eastern Lhasa Terrane: A multiphase magmatic record (∼134–103 Ma) from the Bomi-Chayu batholith 拉萨地体东部早白垩世延长的地壳伸展：波米-察峪岩基多期岩浆记录(~134 ~ 103 Ma

IF 2.6 3区地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS

Tectonophysics

Pub Date : 2025-11-21 DOI: 10.1016/j.tecto.2025.231011

Yihu Zhang , Dongliang Liu , Xuxuan Ma , Haibing Li , Guilong Mi , Xunzhang Zhu , Wang Li

The Early Cretaceous (133–109 Ma) Bomi-Chayu batholith in the easternmost Lhasa terrane provides key insights into crustal growth and tectonic evolution, yet its petrogenesis and geodynamic setting remain contentious. Integrated petrographic, geochronological, geochemical, and isotopic analyses of three granitic suites identify crystallization ages of 134.3 Ma, 116.7–118.0 Ma, and 102.6–102.8 Ma, extending the known duration of regional magmatism. The ∼134 Ma and ∼103 Ma granites are classified as A2-type, formed under high-temperature, low-pressure settings. The ∼134 Ma biotite monzogranites show enriched isotopic compositions, suggesting derivation from ancient crustal sources. In contrast, the ∼103 Ma monzogranites exhibit decoupled ε_Nd(t)-ε_Hf(t) values, consistent with dehydration remelting of ancient crust. The ∼117 Ma granitoid suit is synchronous with a regional magmatic flare-up. The granodiorites in this stage display I-type affinities, with enriched Sr-Nd but relatively depleted zircon Hf isotopes. Geochemical and isotopic trends indicate hybridization between mantle-derived melts (represented by coeval gabbrodiorites and basalts) and crustal components (represented by coeval biotite monzogranites), followed by fractional crystallization and minor upper-crustal contamination. Magmatic types and isotopic compositions correlate the Bomi-Chayu batholith with the magmatic belt in the central Lhasa terrane. The two-stage A-type granites, together with synchronous I-S-type granitoids and bimodal volcanism, provide robust evidence for prolonged crustal extension in the eastern Lhasa terrane (at least the Bomi-Chayu area) during ∼134–103 Ma. We interpret this extensional regime as the result of slab rollback of the northward subducted Neo-Tethyan oceanic lithosphere.

拉萨地体最东端早白垩世（133-109 Ma） Bomi-Chayu基为研究地壳生长和构造演化提供了重要线索，但其岩石成因和地球动力学背景仍存在争议。综合岩石学、年代学、地球化学和同位素分析，确定了三套花岗岩的结晶年龄分别为134.3 Ma、116.7 ~ 118.0 Ma和102.6 ~ 102.8 Ma，延长了已知的区域岩浆活动持续时间。~ 134 Ma和~ 103 Ma花岗岩为a2型，形成于高温低压环境。~ 134 Ma黑云母二长花岗岩显示出丰富的同位素组成，表明其来源于古代地壳。而~ 103 Ma二长花岗岩的εNd(t)-εHf(t)值不耦合，与古地壳脱水重熔相一致。~ 117 Ma花岗岩套装与区域性岩浆爆发同步。该阶段花岗闪长岩呈i型亲和，Sr-Nd富集，锆石Hf同位素相对富集。地球化学和同位素趋势表明，幔源熔体（以同代辉长闪长岩和玄武岩为代表）和地壳成分（以同代黑云母二长花岗岩为代表）之间存在杂交，然后是分馏结晶和轻微的地壳上污染。岩浆类型和同位素组成与拉萨地体中部波米-察峪岩浆岩带相对应。两期a型花岗岩与同步的i- s型花岗岩和双峰火山作用为拉萨地体东部（至少是波米-察峪地区）在~ 134-103 Ma期间的地壳伸展提供了有力的证据。我们认为这种伸展状态是新特提斯洋岩石圈向北俯冲的板块回退的结果。

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引用次数: 0

Hot orogeny during flat-slab subduction decouples upper plate from basal tractions 平板俯冲期间的热造山运动使上部板块与基底牵引力分离

IF 2.6 3区地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS

Tectonophysics

Pub Date : 2025-11-20 DOI: 10.1016/j.tecto.2025.231009

Andrew V. Zuza , Dominik R. Vlaha , Terry Lee , Wenrong Cao

During plate convergence, shallow subduction or underthrusting of the lower-plate lithosphere beneath an overriding plate often results in far-field intraplate deformation, as observed in the Late Cretaceous–Paleogene North American Laramide or Cenozoic Himalayan-Tibetan orogen. Perplexingly, during this shallow-slab process, wide expanses of crust between the plate boundary and intraplate orogen do not experience significant synchronous deformation. These apparently undeformed crustal regions may reflect (1) a strong, rigid plate, (2) increased gravitational potential energy (GPE) to resist shortening and uplift, or (3) decoupling of the upper-plate lithosphere from any basal tractions. Here we review the geology of three orogens that formed due to flat slab subduction or underthrusting: the Himalayan-Tibetan, Mesozoic southeast China, and Laramide orogens. These orogens all involved intraplate deformation >1000-km from the plate boundary, large regions of negligible crustal shortening between the plate-boundary and intra-plate thrust belts, hot crustal conditions within the hinterland regions, and extensive upper-plate porphyry copper mineralization. A hot and weak hinterland is inconsistent with it persisting as an undeformed rigid block. GPE analysis suggests that hinterland quiescence is not uniquely due to thickened crust and elevated GPE, as exemplified by shallow marine sedimentation with low surface elevations in SE China. Comparison of these intracontinental orogens allows us to advance a general model, where hot orogenic hinterlands with a weak, mobile lower crust allow decoupling from underlying basal tractions exerted from flat-slab or underthrusting events. This hypothesis suggests that basal tractions locally drive intraplate orogens, at least partially controlled by the strength of the upper-plate lithosphere.

令人费解的是，在这个浅板块作用过程中，板块边界和板块内造山带之间的大面积地壳并没有经历明显的同步变形。这些表面上未变形的地壳区域可能反映了(1)一个强大的刚性板块，(2)增加的重力势能（GPE）以抵抗缩短和隆起，或(3)板块上部岩石圈与任何基底牵引力的解耦。这些造山带均涉及距板块边界1000公里的板块内变形、板块边界与板块内冲断带之间可忽略不计的大面积地壳缩短、腹地的热地壳条件以及广泛的上板块斑岩铜矿化。炎热而脆弱的腹地与它作为一个未变形的刚性块而持续存在是不一致的。GPE分析表明，地壳增厚和GPE升高并不是腹地静止的唯一原因，中国东南部地表低海拔浅海沉积就是例证。对这些陆内造山带的比较使我们提出了一个一般的模型，在这个模型中，具有弱的、活动的下地壳的热造山带腹地允许从平板或逆冲活动施加的下伏基底牵引力中分离出来。这一假说表明，基底牵引力局部驱动板内造山带，至少部分受上板块岩石圈强度的控制。

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引用次数: 0

A data-driven approach to estimating the heat flow distribution in Mexico 估算墨西哥热流分布的数据驱动方法

IF 2.6 3区地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS

Tectonophysics

Pub Date : 2025-11-17 DOI: 10.1016/j.tecto.2025.231005

Heng Zhang , Yiheng Cai , Shinan Lang , Xiangbin Cui , Xiaoqing Zhang

Heat flow is an important parameter reflecting the thermal structure of the Earth's interior and a key indicator of geothermal resource potential. Mexico lies at the tectonic intersection of the Pacific Ring of Fire and holds potential for geothermal energy exploration. Existing studies primarily use traditional interpolation methods, magnetic data inversion, or similarity methods for regional heat flow estimation. However, these approaches are limited by sparse and unevenly distributed data as well as crustal complexities, resulting in difficulties in capturing detailed spatial heterogeneity of heat flow. To accurately predict the surface heat flow distribution in the Mexico region, this study proposes an integrated framework combining two-stage feature selection and a cascaded machine learning model. First, a compact and informative feature set was constructed using a two-stage selection process that integrates correlation analysis and modeling-based evaluation. The selected features include lithosphere-asthenosphere boundary (LAB) depth, gravity mean curvature, 230 km shear wave velocity, 300 km shear wave velocity, topography (elevation), distance to ridge, and distance to volcano. Subsequently, an initial heat flow prediction was generated using a Random Forest (RF) model based on this feature set. Finally, both the initial prediction and the selected features were jointly input into an Extreme Gradient Boosting (XGBoost) model for further learning, resulting in a more accurate heat flow estimation. A 0.5° × 0.5° resolution heat flow distribution map of Mexico was generated based on key geological features. The map reveals that Mexico's heat flow exhibits a spatial distribution characterized by high values in the west and low values in the east, with extreme values located along volcanic belts. High heat flow concentrates in central-southern Mexico and the Gulf of California coast; low values occur along the south Pacific coast, southern Gulf of Mexico, and Yucatán Peninsula.

热流是反映地球内部热结构的重要参数，也是地热资源潜力的重要指标。墨西哥位于环太平洋火山带的构造交汇处，具有地热能源勘探的潜力。现有研究主要采用传统的插值方法、磁资料反演方法或相似方法进行区域热流估算。然而，这些方法受到数据稀疏和分布不均匀以及地壳复杂性的限制，导致难以捕获详细的热流空间异质性。为了准确预测墨西哥地区的地表热流分布，本研究提出了一种结合两阶段特征选择和级联机器学习模型的集成框架。首先，采用关联分析和基于建模的评估相结合的两阶段选择过程构建了一个紧凑且信息丰富的特征集。选取的特征包括岩石圈-软流圈边界（LAB）深度、重力平均曲率、230 km横波速度、300 km横波速度、地形（高程）、到山脊的距离和到火山的距离。随后，基于该特征集，使用随机森林（RF）模型生成初始热流预测。最后，将初始预测和选择的特征共同输入到极端梯度增强（XGBoost）模型中进行进一步学习，从而获得更准确的热流估计。根据墨西哥主要地质特征，生成了分辨率为0.5°× 0.5°的热流分布图。该地图显示，墨西哥的热流呈现出西高东低的空间分布特征，极值位于火山带附近。高热流集中在墨西哥中南部和加利福尼亚湾沿岸；低值出现在南太平洋沿岸、墨西哥湾南部和Yucatán半岛。

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引用次数: 0

Differential lithospheric deformation in central Mongolia revealed by seismic radial anisotropy 地震径向各向异性揭示的蒙古中部岩石圈差异变形

IF 2.6 3区地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS

Tectonophysics

Pub Date : 2025-11-17 DOI: 10.1016/j.tecto.2025.231003

Mengfan Jiang , Xuewei Bao

Central Mongolia, recording Phanerozoic accretion and continental growth, has experienced varying intracontinental deformation since the Cenozoic. These include dome-like uplift of the Hangai Dome accompanied by diffuse normal faults with low seismicity, but shortening at its peripheries marked by significant strike-slip/thrust motions with intensive seismicity. Nevertheless, how this complex intracontinental deformation is accommodated by deep strain partitioning remains elusive. We present a new high-resolution 3-D radially anisotropic shear-wave velocity model of the lithosphere beneath central Mongolia using ambient noise tomography with data mainly from two dense seismic arrays. Specifically, in the mid-lower crust, the Hangai Dome shows weak anisotropy, indicating relatively weak deformation due to its cratonic basement, whereas the dome's peripheries feature strong positive radial anisotropy, suggesting intensive sub-horizontal ductile shear deformation. Additionally, we demonstrate the presence of the uppermost-mantle partial melting and further constrain the melt fraction and shape by radial anisotropy, which suggest a northeastward decrease in lithospheric strain across the Hangai Dome and its peripheries, likely due to the propagation and subsequent attenuation of NE-directed compressive stress from the India-Asia collision through central Mongolia. Considering the heterogenous lithospheric rheology, our findings provide novel insights into the lithospheric strain partitioning below the complex intracontinental deformation field in central Mongolia.

中蒙古地区记录了显生宙增生和大陆生长，自新生代以来经历了不同程度的陆内变形。其中包括穹状隆起伴弥漫性正断层，地震活动性低，但其外围缩短，走滑/逆冲运动明显，地震活动性强。然而，这种复杂的陆内变形是如何被深层应变分配所适应的，仍然是难以捉摸的。利用环境噪声层析成像技术，利用两个密集地震阵列的数据，建立了蒙古中部岩石圈径向各向异性的高分辨率三维横波速度模型。其中，在中下地壳中，杭盖穹隆的各向异性较弱，表明受克拉通基底的影响，变形相对较弱，而穹隆外围的正向径向各向异性较强，表明亚水平韧性剪切变形强烈。此外，我们证明了上地幔部分熔融的存在，并通过径向各向异性进一步限制了熔体的比例和形状，这表明整个Hangai Dome及其外围的岩石圈应变向东北方向减少，可能是由于印度-亚洲碰撞通过蒙古中部传播和随后衰减的ne向压应力。考虑到非均质岩石圈流变学，我们的发现为蒙古中部复杂陆内变形场下岩石圈应变分配提供了新的认识。

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引用次数: 0

Slow slip events in Mexico: A historical perspective 墨西哥慢滑事件：一个历史的视角

IF 2.6 3区地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS

Tectonophysics

Pub Date : 2025-11-16 DOI: 10.1016/j.tecto.2025.230978

Víctor M. Cruz-Atienza , Sara Franco , Vladimir Kostoglodov , Josué Tago , Ekaterina Kazachkina , Jorge Real , Carlos Villafuerte , Raymundo Plata-Martínez

This paper introduces a historical catalogue of slow slip events (SSE) for the Mexican subduction zone. The catalogue incorporates all 25 SSEs recorded since they were discovered in 1997. The inversion of GPS data for ten SSEs in Guerrero and five in Oaxaca reveals a clear slow slip segmentation along the Middle America Trench, with slip maxima between 30 and 40 km depth in both regions. SSEs in Guerrero are significantly larger, with

M_{w} = 7.14 \pm 0.18

and a duration of

10.3 \pm 6.5

months, whereas in Oaxaca,

M_{w} = 6.84 \pm 0.16

with a duration of

7.0 \pm 4.3

months. Such discrepancy results from the subhorizontal geometry of the Cocos Plate in Guerrero, which favors a more extensive SSE habitat. The extent and along-strike segmentation of SSEs appear to be structurally controlled by the subduction of the Orozco and O'Gorman fracture zones. For the inversions, we used consistent GPS data processing that preserves the North American reference frame and the actual SSEs crustal rebounds. All data were curated to minimize seasonal noise, and interpreted throughout the ELADIN inversion method. Five of the six most recent M7+ earthquakes in the region were preceded and most likely triggered by an SSE. This earthquake cluster began in 2012 after a 17-year period of quiescence, during which large SSEs occurred. While the SSEs appear to be necessary for initiating large ruptures, this is not enough until sufficient energy has regionally accumulated in the subduction zone. The Mexican seismic record since 1800 suggests that every ∼15 years the subduction zone reaches a critical state in which SSEs become large earthquake precursors.

本文介绍了墨西哥俯冲带慢滑事件的历史目录。该目录包含了自1997年发现以来记录的所有25颗超新星。格雷罗州10个sss和瓦哈卡州5个sss的GPS数据反演显示，沿中美洲海沟存在明显的慢滑动分割，两个地区的最大滑动深度在30 ~ 40 km之间。格雷罗州的sss更大，Mw=7.14±0.18，持续时间为10.3±6.5个月，而瓦哈卡州的sss =6.84±0.16，持续时间为7.0±4.3个月。这种差异是由于格雷罗Cocos板块的亚水平几何形状，这有利于更广泛的SSE栖息地。ssi的范围和沿走向分段在构造上受Orozco和O’gorman断裂带俯冲作用的控制。对于反演，我们使用了一致的GPS数据处理，保留了北美参考框架和实际的SSEs地壳反弹。所有数据都经过整理，以尽量减少季节性噪音，并通过ELADIN反演方法进行解释。该地区最近发生的6次7级以上地震中，有5次是由SSE引发的。在经历了17年的平静期后，这个地震群开始于2012年，在此期间发生了大型地震。虽然sse似乎是引发大破裂的必要条件，但这还不够，直到在俯冲带积累了足够的能量。墨西哥自1800年以来的地震记录表明，每~15 年，俯冲带就达到一个临界状态，在这个状态下，地壳结构成为大地震的前兆。

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引用次数: 0

Early Triassic tectonic inversion in South China linked to the oblique closure of the Paleo-Tethys Mianlue Ocean 华南早三叠世构造反转与古特提斯绵留洋斜闭有关

IF 2.6 3区地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS

Tectonophysics

Pub Date : 2025-11-16 DOI: 10.1016/j.tecto.2025.231004

Qiang Xu , Wei Deng , Chunyuan Gu , Yu Cao , Xiucheng Tan , Ling Li , Bing Luo , Zhanfeng Qiao , Yibo Li , Yao Xie , Stephen Kershaw

The closure timing of the Paleo-Tethyan Mianlue Ocean is crucial for undestanding plate tectonic reorganization and paleoenvironment changes. However, it remains highly debated, with estimates varying from the Late Permian to the Late Triassic due to insufficient geologic records within the suture zone. In this study, we investigate the Early Triassic inversion structures in the Huayingshan tectonic belt, located south of the Mianlue suture zone, to better constrain the collisional timing. Structural analysis of the Guanyin Gorge anticline in the southern HTB identifies positive inversion structures within the Lower Triassic Feixianguan Formation, as evidenced by decrease and eventually reversal in sense of displacements along the fault planes. The thicker strata and onlap geometries observed in the hanging walls relative to the footwalls provide evidence for syn-depositional fault activity. Zircon U-Pb dating of tuff layers at Peijiawan constrain the timing of onset of the syn-depositional reverse faulting between 250 and 249 Ma. Moreover, storm deposits are prevalently developed in the Feixianguan Formation and even more abundant within the fault-active interval. The contemporaneous development of similar inversion structures and storm deposits on tidal platform throughout the northern Sichuan Basin indicates a broader, regional-scale tectono-sedimentary episode driven by the regional tectonic transition from extension to compresion, which linked to complete consumption of the Paleotethyan Mianlue Ocean and onset of collision between the south China and north China blocks at 249 Ma. The collisional compression fuelled a sustained marine transgression, consequently amplifying storm sedimentation across the Upper Yangtze region.

古特提斯绵留洋的闭合时间对了解板块构造重组和古环境变化具有重要意义。然而，由于缝合带内地质记录不足，从晚二叠世到晚三叠世的估计仍存在很大争议。为了更好地约束碰撞时间，本研究对位于绵略缝合带南侧的华蓥山构造带进行了早三叠世逆构造研究。对观音峡南段背斜进行构造分析，发现下三叠统飞仙关组内存在正反转构造，沿断裂面位移减小并最终反转。相对于下盘，上盘观察到较厚的地层和上覆的几何形状为同沉积断层活动提供了证据。裴家湾凝灰岩层的锆石U-Pb定年限制了同沉积逆断裂的起裂时间在250 ~ 249 Ma之间。此外，风暴沉积主要发育于飞仙关组，在断动层段内更为丰富。四川盆地北部类似逆构造和潮台风暴沉积的同期发育表明，在区域构造由伸展向挤压转变的驱动下，发生了一次更广泛的区域尺度的构造-沉积事件，这与249 Ma古特提斯绵略洋的完全消耗和华南与华北地块碰撞的开始有关。碰撞挤压推动了持续的海侵，从而放大了上扬子地区的风暴沉积。

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引用次数: 0

Mantle transition zone dynamics beneath the Northwestern Deccan Volcanic Province, India: Implications for plume mediated upper mantle processes 印度西北德干火山省地幔过渡带动力学：对地幔柱介导的上地幔过程的启示

IF 2.6 3区地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS

Tectonophysics

Pub Date : 2025-11-12 DOI: 10.1016/j.tecto.2025.231000

Rema Vaishali , Madhusudhanarao Katlamudi , Ayoub Kaviani , Georg Rümpker

The Deccan Volcanic Province (DVP), formed ∼65 Ma during India's northward drift and linked to the Réunion plume, reveals complex upper-mantle structures. This study uses P receiver function (RF) analysis from 76 broadband stations in Gujarat, Western India, to image upper-mantle discontinuities (d410 and d660) beneath the north-western DVP. RF depth migration was performed using 1-D and 3-D tomographic velocity models—GYPSUM, LLNL-G3Dv3, MEAN2, and a combined regional model (up to 300 km depth) incorporating LLNL-G3Dv3. The estimated mantle transition zone (MTZ) thickness varies from 233 to 248 km in Kachchh, Saurashtra, Cambay, South Gujarat, and the Arabian Sea, while in North Gujarat and the Narmada rift zones; it ranges from 251 to 255 km. The d410 discontinuity exhibits a uniform depression (410–430 km), whereas the d660 remains normal to slightly deepened (650–675 km). The eastern North Gujarat, Narmada zone, and parts of Kachchh exhibit a shallow 410 km and depressed 660 km discontinuity, indicating MTZ thickening. The Cambay thermal anomaly, bounded by these colder regions, likely reflects localized small-scale upwelling coupled with the downwelling of ancient subducted slab remnants. Additionally, 520 km discontinuity was detected, with amplitude peaks suggesting a low-velocity layer above d410. The Mean excess temperatures associated with d410 and d660depressions are ∼150 K and ∼ 323 K, respectively. MTZ structure, thermal anomalies, and mantle velocity heterogeneities collectively indicate plume–lithosphere interaction influenced by relic slab dynamics in the genesis of Deccan volcanism.

德干火山省（DVP）形成于印度向北漂移期间的~ 65 Ma，与r地幔柱有关，显示出复杂的上地幔结构。本研究使用来自印度西部古吉拉特邦76个宽带站的P接收函数（RF）分析，对西北DVP下的上地幔不连续体（d410和d660）进行成像。RF深度偏移使用1-D和3-D层析速度模型（石膏、LLNL-G3Dv3、MEAN2）以及包含LLNL-G3Dv3的组合区域模型（深度达300 km）进行。在Kachchh， Saurashtra, Cambay， South Gujarat和Arabian Sea，而在North Gujarat和Narmada裂谷带，估计的地幔过渡带（MTZ）厚度在233 ~ 248 km之间；它的范围从251到255公里。d410不连续面呈均匀凹陷（410 ~ 430 km），而d660不连续面保持正常或略深（650 ~ 675 km）。北古吉拉特邦东部、Narmada地区和Kachchh部分地区表现出410 km的浅层不连续和660 km的凹陷不连续，表明MTZ增厚。坎贝热异常以这些较冷的区域为界，可能反映了局部的小规模上升流和古代俯冲板块残余物的下升流。此外，探测到520 km的不连续层，振幅峰值表明在d410上方存在低速层。与d410和d660凹陷相关的平均过量温度分别为~ 150 K和~ 323 K。MTZ结构、热异常和地幔速度非均质性共同表明了德干火山成因中受遗迹板块动力学影响的柱-岩石圈相互作用。

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引用次数: 0

Revealing deep-rooted pre-Paleozoic fault systems in the lower Yangtze region: Insights from 3D magnetic inversion and gravity inversion and integrated geophysical interpretation 揭示下扬子地区前古生代深层断裂体系：三维磁重反演与综合地球物理解释的启示

IF 2.6 3区地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS

Tectonophysics

Pub Date : 2025-11-12 DOI: 10.1016/j.tecto.2025.231001

Chongjin Zhao, Luolei Zhang, Huang Zuwei, Peng Yu

The Lower Yangtze region lies between the North China Craton and Cathaysia Block; yet, the offshore continuity of major sutures and the role of inherited basement faults remain debated. We integrate 3-D inversions of regional magnetic and gravity data for crustal framework imaging without reduction-to-the-pole. In particular, we perform magnetic inversion directly on the total magnetic intensity (TMI) under oblique field geometry, coupled with a sharp-boundary gravity inversion to the TMI-derived magnetic basement. Petrophysical ranges for densities and susceptibilities provide the sole priors, and edges are mapped with a tilt–hyperbolic–vertical–horizontal (THVH) operator. Misfits reach observational noise levels, and the recovered volumes resolve long- to intermediate-wavelength structures. Magnetization is concentrated beneath the East China Sea shelf and southern South Yellow Sea, while 10–20 km density slices delineate alternating uplift–depression couplets. Three surfaces (i.e., the Magnetic-basement top, Paleozoic-basement proxy depth, and Proterozoic residual-thickness proxy) define coherent gradients that, together with THVH ridges, map a consistent fault framework. We infer (i) an eastward offshore continuation of the Jiangshan–Shaoxing Fault that bends northeast and is truncated near the southwestern margin of Jeju Island; (ii) a lithosphere-scale Yangtze–North China boundary coincident with the Korea–West Fault; and (iii) four inherited NE–EW faults that segment the region into alternating uplifts and depressions. The architecture supports Late Cretaceous back-arc extension and selective reactivation of Precambrian discontinuities.

下扬子地区位于华北克拉通与华夏地块之间；然而，主要缝合线的海上连续性和继承的基底断层的作用仍然存在争议。我们整合了区域磁场和重力数据的三维反演，用于地壳框架成像，而无需还原到极点。特别是，我们直接对斜场几何形状下的总磁强度（TMI）进行了磁反演，并对TMI导出的磁基底进行了锐边界重力反演。岩石物理范围的密度和敏感性提供了唯一的先验，边缘是用倾斜-双曲-垂直-水平（THVH）算子绘制的。失配达到观测噪声水平，恢复的体积分解出长至中波长结构。磁化集中在东海陆架和南黄海南部，而10-20公里的密度片描绘了交替的升降对联。三个面（即磁基底顶部、古生代基底代理深度和元古代残余厚度代理）定义了相干梯度，并与THVH脊一起绘制了一致的断层格架。我们推断(1)江山-绍兴断裂向东延伸，向东北弯曲，在济州岛西南边缘附近被截断；（ii）与韩-西断裂重合的岩石圈尺度的扬子-华北边界；(3) 4条继承的NE-EW断裂，将该地区划分为隆升和坳陷交替。该构造支持晚白垩世弧后伸展和前寒武纪不连续性的选择性恢复。

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引用次数: 0

3D magnetotelluric imaging of lithospheric magmatic systems in the Yitong Volcanic Area, Northeast China: Implications for fault-zone segmentation and seismic rupture dynamics along the Yilan-Yitong Fault 东北伊通火山区岩石圈岩浆系统三维大地电磁成像：宜兰-伊通断裂断裂带分割和地震破裂动力学意义

IF 2.6 3区地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS

Tectonophysics

Pub Date : 2025-11-12 DOI: 10.1016/j.tecto.2025.231002

Cong Cao , Lingqiang Zhao , Yan Zhan , Yanfu Qi , Xiangyu Sun , Xiong Yang , Hongbin Lv , Qingliang Wang , Bowen Hou , Wenwen Qi

The Yitong Volcanic Area (YVA) in Jilin Province is a relatively rare “compression type” volcanic system worldwide. Its formation mechanism and eruption mode have unique features. The Yilan-Yitong Fault (YYF) runs through this volcanic rock belt and has demonstrated prominent segmented fracture characteristics since the Quaternary Period. The paleoseismic activity of the Yitong Fault Zone (YFZ) is different from that of other fault zones within this area. This study aimed to investigate the deep magma system in the YVA and its influence on the segmented activities of YYF. Magnetotelluric (MT) measurements were performed in the YVA. A total of 87 MT sites were arranged in the area. A high-resolution three-dimensional (3D) electrical structure model of the lithospheric scale from the crust to the upper mantle in the study area was established with the 3D inversion method. This model suggests that the shallow section of the upper crust of the YVA and the northwestern part of the Songliao Basin were mainly low-resistivity zones, which corresponded to the widely distributed sedimentary layers in this area. The middle and lower crust in the study area was primarily a complete high-resistivity body. A large-scale magmatic system began to appear at a depth of 25 km in the YVA. This magmatic system continued to extend downward, exceeding 70 km. The magma chamber in the YVA was in contact with the YYF in the lower crust. The YYF was the dominant material surging upward through the magma channel. Additionally, deep magmatic activities exerted a crucial influence on the seismic rupture segmentation characteristics along the YYF and the uplift mechanism of the Yitong Basin. The results of this study provide crucial geophysical constraints for depicting the fine depth structure of the YVA while enlightening the investigation of the rupture propagation mechanism within the volcanic terrain fault zone.

吉林省伊通火山区是世界上较为罕见的“压缩型”火山体系。其形成机制和喷发方式具有独特的特点。宜兰-伊通断裂穿过该火山岩带，第四纪以来表现出明显的分段断裂特征。伊通断裂带（YFZ）的古地震活动与该区其他断裂带不同。本研究旨在探讨YVA深部岩浆系统及其对YYF分段活动的影响。大地电磁（MT）测量在YVA进行。该地区共设置了87个MT站点。利用三维反演方法，建立了研究区从地壳到上地幔的岩石圈尺度的高分辨率三维电性结构模型。该模型表明，YVA上地壳浅部和松辽盆地西北部以低电阻率带为主，对应了该地区沉积层的广泛分布。研究区中下地壳主要为完整的高阻体。在YVA的25公里深处开始出现大规模的岩浆系统。这个岩浆系统继续向下延伸，超过70公里。YVA的岩浆房与下地壳的YYF有接触。YYF是通过岩浆通道向上涌动的主要物质。此外，深部岩浆活动对沿YYF的地震破裂分段特征和伊通盆地的隆升机制也有重要影响。本研究结果为描绘YVA的精细深度结构提供了重要的地球物理约束条件，同时也为火山地形断裂带内破裂传播机制的研究提供了启示。

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引用次数: 0

Precise relocation of the 14 August 2021 Mw 7.2 Nippes, Haiti, earthquake sequence using broadband and citizen-hosted short-period seismometers 使用宽带和公民托管的短周期地震仪精确定位2021年8月14日海地Nippes的Mw 7.2地震序列

IF 2.6 3区地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS

Tectonophysics

Pub Date : 2025-11-12 DOI: 10.1016/j.tecto.2025.230982

Sylvert Paul , Tony Monfret , Eric Calais , Françoise Courboulex , Bertrand Delouis , Anthony Lomax , Bernard M. de Lépinay , Steeve J. Symithe , Anne Deschamps , David Ambrois , Sadrac St Fleur , Dominique Boisson

On 14 August 2021, the Southern Peninsula of Haiti experienced a M

_{w}

7.2 earthquake, 15 years after the devastating M

_{w}

7.0 event that struck the capital city of Port-au-Prince on 12 January 2010. We use the data from a local temporary broadband seismic network, a national network of low-cost seismometers, and regional seismic networks, together with a probabilistic, global-search, non-linear location method (NLL-SSST-coherence), to obtain a catalog of 5341 precisely relocated events spanning 20 August 2021 to 6 February 2022, with local magnitudes ranging from 0.5 to 5.6. We compute focal mechanisms for a subset of 73 events through waveform inversion. The catalog can be split into aftershocks directly related to the Nippes earthquake rupture process, and two off-rupture clusters. A first one concerns the Anse-à-Veau–Miragoâne area and corresponds mostly to the aftershock sequence of two M

_{w}

5.3 and 4.9 earthquakes that likely activated a segment of the offshore, south-dipping, Jérémie–Malpasse reverse fault system. A second sequence, offshore Jérémie and clustered close to the offshore trace of that same fault, started immediately after the Nippes mainshock and continued during the entire time interval of the present study. The swarm–like temporal distribution of this sequence, as well as evidence for directional propagation of the epicenters, indicate that it was likely driven by fluid migration. We interpret this seismicity as the result of oblique sub-crustal slip on a south-dipping fault which accounts for oblique convergence between the Gonâve and Caribbean plates in southern Hispaniola. Strain in the crust then partitions between reverse faulting on the Jérémie–Malpasse fault system, strike-slip on the Enriquillo fault, and hybrid faulting in between. Seismic hazard assessment for the region should therefore account for faults other than the Enriquillo fault as potential sources for future earthquakes.

2021年8月14日，海地南部半岛发生里氏7.2级地震，距2010年1月12日首都太子港发生里氏7.0级地震已有15年。我们使用来自当地临时宽带地震台网、国家低成本地震仪台网和区域地震台网的数据，以及概率、全局搜索、非线性定位方法（nl - ssst相干性），获得了5341个精确定位的事件目录，时间横跨2021年8月20日至2022年2月6日，当地震级范围为0.5至5.6。我们通过波形反演计算了73个事件子集的震源机制。该目录可分为与尼普斯地震破裂过程直接相关的余震和两个非破裂集群。第一个地震与Anse -à-Veau-Miragoâne地区有关，主要与两次5.3和4.9级地震的余震序列相对应，这些地震可能激活了离岸、向南倾斜的jsamrsammie - malpasse逆断层系统的一部分。第二个序列，离岸的jsamrsammie，聚集在同一断层的离岸痕迹附近，在尼普斯主震之后立即开始，并在本研究的整个时间间隔中继续进行。该序列的群状时间分布以及震中定向传播的证据表明，它可能是由流体运移驱动的。我们将这种地震活动性解释为南倾断层上斜向地壳下滑动的结果，该断层解释了伊斯帕尼奥拉岛南部gon和加勒比板块之间的斜向辐合。然后，地壳中的应变被划分为jsamrsammi - malpasse断层系统的逆断层、Enriquillo断层的走滑断层和介于两者之间的混合断层。因此，该地区的地震危险性评估应考虑到除Enriquillo断层以外的其他断层是未来地震的潜在震源。

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引用次数: 0