| 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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| 关键词:ambient noise tomography S-wave velocity structure Antarctic Peninsula Southern South America Scotia plate Phoenix plate |
| 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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| Analysis of S-wave Velocity Structure of Blocks around the Antarctica Great Wall Station Based on Noise Tomography |
| 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. |
| GUO Zhaoyue,CHANG Lijun,SUN Huigui,PEI Junling.2026.Analysis of S-wave Velocity Structure of Blocks around the Antarctica Great Wall Station Based on Noise Tomography[J].Acta Geoscientica Sinica,47(3):493-506. |
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