• ISSN 2097-1893
  • CN 10-1855/P
申宇彤,杨光亮,谈洪波,王嘉沛,张明辉,申重阳. 2022. 川滇及邻区布格重力异常与地壳密度结构研究进展. 地球与行星物理论评,53(3):316-330. doi: 10.19975/j.dqyxx.2022-001
引用本文: 申宇彤,杨光亮,谈洪波,王嘉沛,张明辉,申重阳. 2022. 川滇及邻区布格重力异常与地壳密度结构研究进展. 地球与行星物理论评,53(3):316-330. doi: 10.19975/j.dqyxx.2022-001
Shen Y T, Yang G L, Tan H B, Wang J P, Zhang M H, Shen C Y. 2022. Review on Bougue gravity anomaly and crustal density structure in Sichuan-Yunnan and its adjacent areas. Reviews of Geophysics and Planetary Physics, 53(3): 316-330. doi: 10.19975/j.dqyxx.2022-001
Citation: Shen Y T, Yang G L, Tan H B, Wang J P, Zhang M H, Shen C Y. 2022. Review on Bougue gravity anomaly and crustal density structure in Sichuan-Yunnan and its adjacent areas. Reviews of Geophysics and Planetary Physics, 53(3): 316-330. doi: 10.19975/j.dqyxx.2022-001

川滇及邻区布格重力异常与地壳密度结构研究进展

Review on Bougue gravity anomaly and crustal density structure in Sichuan-Yunnan and its adjacent areas

  • 摘要: 川滇及邻区是青藏高原东流物质往SE-SSE旋转和逃逸的主要场所,地质构造与地震活动十分活跃. 本文总结了川滇及其邻区区域布格重力异常和地壳密度结构研究的近期成果和重要进展:(1)利用重力与GNSS定位技术,获得了8条重力探测剖面的布格重力异常信息,利用多种地球物理观测共同约束的重力反演技术,构建了青藏高原东南缘及邻区地壳密度结构的基本构架;(2)通过小波分解及归一化梯度等重力信号分离、提取方法,发现了川滇菱形地块顺时针旋转运动的重力学新证据;(3)通过玉树MS7.1、芦山MS7.0和鲁甸MS6.5地震的科考研究,加深了对青藏高原东南缘地震孕育构造环境的认识:大型左旋走滑剪切断裂带(甘孜—玉树、鲜水河、小江)和大型逆冲推覆构造(龙门山)两侧密度结构差异显著,两大构造均为区域地震活动控制性断裂,鲁甸震区地震活动可能与小江断裂带“东迁”作用有关;龙门山断裂带的推覆特征和滑脱层构造,可能是芦山地震发生在后山断裂的重要因素.

     

    Abstract: Sichuan-Yunnan and its adjacent area are the main places where the eastward material flow from the Tibet Plateau escapes and spins to SE-SSE with active geological formations and frequent seismic activity. The study of the crustal structure and material transport characteristics of this region is important to reveal the mechanism of earthquake occurrence here. It can also deepen the understanding of the tectonic activity mechanism of the southeastern margin of the Tibet Plateau. This paper summarizes recent achievements and important advances in the study of regional Bouguer gravity anomaly and crustal density structure in Sichuan-Yunnan and its adjacent areas. (1) Bouguer gravity anomaly information of eight gravity profiles was obtained by using gravity and GNSS positioning techniques, and the basic framework of crustal density structure of the southeastern margin of the Qinghai-Tibet Plateau and its adjacent areas was constructed by using gravity inversion techniques constrained by various geophysical observations. (2) New gravitational evidence of clockwise rotation of the Sichuan-Yunnan rhomboid massif was found through the separation and extraction of gravity signals by wavelet decomposition and normalized gradient. (3) Through the scientific research of the Yushu MS7.1, Lushan MS7.0 and Ludian MS6.5 earthquakes, we have deepened our understanding of the seismogenic tectonic environment in the southeastern margin of the Tibet Plateau. There are significant differences in density distribution on sides of the left-slip shear fault zone (Ganzi-Yushu, Xianshuihe and Xiaojiang) and the large thrust nappe structure (Longmen Shan), both of which are regional seismicity-controlled faults. The seismicity of the Ludian earthquake zone may be related to the eastward migration of the Xiaojiang fault zone. The nappe characteristics and detachment structure of the Longmenshan fault zone may be an important factor in the occurrence of the Lushan earthquake at the Houshan fault.

     

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