| 基于噪声成像分析南极长城站周边块体S波速度结构 |
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| 引用本文：郭钊玥,常利军,孙回归,裴军令.2026.基于噪声成像分析南极长城站周边块体S波速度结构[J].地球学报,47(3):493-506. |
| DOI：10.3975/cagsb.2025.121621 |
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| 基金项目:本文由国家自然科学基金项目(编号: 42374079; 41930218)、国家重点研发计划项目(编号: 2022YFC2807401)和中国地震局地球物理研究所自主立项项目(编号: JY2023Z01)联合资助。 |
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| 中文摘要:南极半岛北部位于多个板块的交汇区域, 构造格局复杂, 研究其深部结构特征对认识该区域板块间的相互作用和岩石圈演化有重要意义。本文基于中国南极长城站地震台及周边8个地震台站2019—2021年的连续波形数据开展噪声成像研究, 得到了穿过各块体不同路径的一维S波速度结构, 并对比分析了其差异。结果显示, 各块体S波速度结构特征明显: 南极半岛的地壳S波速度随深度匀速增大, 表明陆壳内部物质构成相对均匀; 相比之下, 布兰斯菲尔德海峡的地壳正处于向洋壳转换的阶段, 存在活跃的岩浆活动, 其地壳S波速度较低。南美洲南部的地壳浅层速度较低, 可能受到较厚沉积层的影响, 且该区域西部的速度低于东部, 反映了智利海沟俯冲构造的影响。相对于南美洲南部, 曾与其相连的南极半岛具有更高的地壳S波速度, 地震活动性、热流值和俯冲带构造的差异均表明其地壳结构更稳定。此外, 南北斯科舍脊的S波速度结构差异显著, 可能与二者具有不同的板块边界性质有关; 菲尼克斯板块的整体结构比较均匀; 斯科舍板块与同样作为大洋板块的菲尼克斯板块具有相似的S波速度结构, 可能是因为二者均产生于洋中脊的扩张。 |
| 中文关键词:背景噪声成像 S波速度结构 南极半岛 南美南部 斯科舍板块 菲尼克斯板块 |
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| Analysis of S-wave Velocity Structure of Blocks around the Antarctica Great Wall Station Based on Noise Tomography |
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| Abstract:The northern Antarctic Peninsula is situated in the convergence of the Antarctic, South American, Scotia, and Phoenix Plates, exhibiting a complicated tectonic configuration. The study of its deep structural features has the potential to provide constraints for understanding plate interactions and lithospheric evolution in the region. In this study, we conducted ambient noise tomography using broadband continuous waveform data recorded by the China–Antarctica Great Wall Station (CCZ) and eight nearby seismic stations between 2019 and 2021. A one-dimensional S-wave velocity structure passing through the different ray paths of each block was obtained and the velocity differences among the blocks were compared and analyzed. The results indicated that the S-wave velocity structures of each block were clearly characterized. The S-wave velocity of the crust in the Antarctic Peninsula increases uniformly with depth, suggesting a relatively homogeneous composition of materials within the continental crust. Conversely, the S-wave velocity was lower within the crust of the Bransfield Strait, which is in the process of continental-to-oceanic crust transition, and active volcanism and magmatic activities are present in the Strait. The shallow velocity in the crust of southern South America is low, probably owing to the presence of thicker sedimentary layers, and the lower velocity on the western side than on the eastern side may reflect the effects of the subduction tectonics of the Chilean Trench. The Antarctic Peninsula and South America were once connected continents. The Antarctic Peninsula has a higher crustal S-wave velocity, weaker seismicity, lower heat-flow values, and inactive subduction-zone tectonics relative to the southern part of South America, suggesting that the Antarctic Peninsula has a more stable crustal structure. In addition, the S-wave velocity structures of the North and South Scotia Ridge are significantly different, which may be related to their different plate boundary properties ; the velocity structures of the western and eastern Phoenix plates are more consistent, reflecting a more homogeneous structure of the plate as a whole; and the Scotia and Phoenix plates, which also serve as oceanic plates, have similar S-wave velocity structures, probably because they both arose from the spreading of mid-oceanic ridges. |
| keywords:ambient noise tomography S-wave velocity structure Antarctic Peninsula Southern South America Scotia plate Phoenix plate |
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