| 青藏高原大型地震断裂带的变形机制 |
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| 关键词:fault rocks deformation mechanism Longmen Shan fault zone Xianshuihe fault zone Tibetan Plateau |
| 基金项目:国家自然科学基金项目(编号: 42230312; 42172262; 42372266; 42072240; 42020104007; 42272270; 42374121)；中国地质科学院基本科研业务费项目(编号: J2403)；中国地质调查局地质调查项目(编号: DD20221630) |
| 作者 | 单位 | E-mail | | 张蕾 | 中国地质科学院地质研究所, 自然资源部大陆动力学重点实验室；江苏东海大陆深孔地壳活动国家野外科学观测研究站 | zhanglei881102@126.com | | 李海兵 | 中国地质科学院地质研究所, 自然资源部大陆动力学重点实验室；江苏东海大陆深孔地壳活动国家野外科学观测研究站 | lihaibing06@163.com | | 王焕 | 中国地质科学院地质研究所, 自然资源部大陆动力学重点实验室；江苏东海大陆深孔地壳活动国家野外科学观测研究站 | | | 吴琼 | 北京石油机械有限公司 | | | 杨少华 | 中国地质科学院地质研究所, 自然资源部大陆动力学重点实验室；江苏东海大陆深孔地壳活动国家野外科学观测研究站 | | | 孙知明 | 中国地质科学院地质力学研究所, 自然资源部古地磁与古构造重建重点实验室 | | | 司家亮 | 中国地质科学院地质研究所, 自然资源部大陆动力学重点实验室；江苏东海大陆深孔地壳活动国家野外科学观测研究站 | | | Marie-Luce CHEVALIER | 中国地质科学院地质研究所, 自然资源部大陆动力学重点实验室；江苏东海大陆深孔地壳活动国家野外科学观测研究站 | | | 曹勇 | 中国地质科学院地质力学研究所, 自然资源部古地磁与古构造重建重点实验室 | | | 郑勇 | 中国地质科学院地质研究所, 自然资源部大陆动力学重点实验室；江苏东海大陆深孔地壳活动国家野外科学观测研究站 | | | 潘家伟 | 中国地质科学院地质研究所, 自然资源部大陆动力学重点实验室；江苏东海大陆深孔地壳活动国家野外科学观测研究站 | | | 刘栋梁 | 中国地质科学院地质研究所, 自然资源部大陆动力学重点实验室；江苏东海大陆深孔地壳活动国家野外科学观测研究站 | | | 赵中宝 | 中国地质科学院地质研究所, 自然资源部大陆动力学重点实验室；江苏东海大陆深孔地壳活动国家野外科学观测研究站 | | | 马绪宣 | 中国地质科学院地质研究所, 自然资源部大陆动力学重点实验室；江苏东海大陆深孔地壳活动国家野外科学观测研究站 | | | 卢海建 | 中国地质科学院地质研究所, 自然资源部大陆动力学重点实验室；江苏东海大陆深孔地壳活动国家野外科学观测研究站 | |
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| Deformation Mechanism of Large Earthquake Fault Zone in the Tibetan Plateau |
| Recently, large earthquakes have occurred frequently, and earthquake mechanism and earthquake faulting have become important topics in society. The deformation mechanism of fault zones, especially large earthquake fault zones, is the key to understanding fault activity and earthquake mechanisms. The aim of this study was to discuss the deformation mechanism of the large earthquake fault zone in the Tibetan Plateau by analyzing recent research on the Longmen Shan and Xianshuihe fault zones in the eastern Tibetan Plateau. The results are as follows: (1) The Wenchuan earthquake simultaneously ruptured on different faults and formed a pseudotachylyte vein at an extremely shallow depth (~732.6 m), which was generated in an unconsolidated, fluid-rich fault gouge. This finding overturns our traditional understanding of earthquakes and deepens our understanding of the mechanical properties of shallow faults. (2) A Late Triassic Mw~7.4 to 7.9 earthquake had occurred along the Yingxiu–Beichuan fault, Longmen Shan fault zone, and the focal mechanism of this large magnitude earthquake was left-lateral, strike-slip motion. The high degree of magnetic anisotropy in the fault rocks is an indication of a high-strain seismogenic environment and a new important indicator of large earthquakes. (3) Three deformation phases were identified in the Wenhuan–Maoxian fault zone during the Cenozoic, in contrast to the predictions of the lower crustal channel-flow extrusion models. (4) Large earthquakes with high frictional heating (>500 °C) have occurred along the Wenhuan–Maoxian fault zone in the past, and the seismogenic environment was a reductive environment with low-temperature hydrothermal fluids. (5) The Xianshuihe fault system is the main boundary for the outward migration of material in southeastern Tibet. The Xianshuihe fault zone, with frequent large earthquakes, exhibits long-term creep deformation behavior. The fluid influx increases the content of strong minerals within the fault core, thereby locally strengthening the creeping fault. These results enrich and improve the faulting theory, improve our understanding of the deformation mechanism of large earthquake fault zones in the Tibetan Plateau, and provide a scientific basis for fault-zone activity, earthquake mechanisms, earthquake risk assessment, and earthquake prevention and reduction. |
| ZHANG Lei,LI Haibing,WANG Huan,WU Qiong,YANG Shaohua,SUN Zhiming,SI Jialiang,Marie-Luce CHEVALIER,CAO Yong,ZHENG Yong,PAN Jiawei,LIU Dongliang,ZHAO Zhongbao,MA Xuxuan,LU Haijian.2024.Deformation Mechanism of Large Earthquake Fault Zone in the Tibetan Plateau[J].Acta Geoscientica Sinica,(6):854-870. |
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