The crustal structure under Sanjiang and its dynamic implications: Revealed by seismic reflection/refraction profile between Zhefang and Binchuan, Yunnan

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• 作者：Zhongjie Zhang (1)
  Zhiming Bai (1)
  Chunyong Wang (2)
  Jiwen Teng (1)
  Qingtian Lü (3)
  Jiliang Li (1)
  Yifeng Liu (1)
  Zhenkuan Liu (4)
  
• 关键词：Sanjiang area ; wide ; angle seismic profile ; crustal structure
• 刊名：Science China Earth Sciences
• 出版年：2005
• 出版时间：September 2005
• 年：2005
• 卷：48
• 期：9
• 页码：1329-1336
• 全文大小：898KB
• 参考文献：1. Pan, Y. S., The evolution of the tectonic structure in north-west Tibetan Plateau, the Exoteric Laboratory of Structure Evolution of the Lithosphere of Institute of Geology and Geophysics, Chinese Academy of Sciences, 1989-990 Annual Report (in Chinese), Beijing: Chinese Science and Technology Press, 1991.
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  11. Bai, Z. M., Wang, C. Y., Structure of the upper crust and tomo-graphy of seismic tectonic condition in Yunnan, Acta Seis-mologica Sinica (in Chinese), 2003, 25(2): 117-27.
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  13. Zhang, Z. J., Qin, Y. L., Chen, Y. et al., To restructure comparability profile of reflection structure in the crust and mantle by wide-angle seismic data, Chinese Journal of Geophysics (in Chi-nese), 2004, 47(3): 469-74.
  14. Peng, X. J., Liu, J. H., Wu, J. H., The Geology in Nujiang- Lancang-Jinshajiang Region (in Chinese), Beijing: Geological Publishing House, 1998, 105.
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• 作者单位：Zhongjie Zhang (1)
  Zhiming Bai (1)
  Chunyong Wang (2)
  Jiwen Teng (1)
  Qingtian Lü (3)
  Jiliang Li (1)
  Yifeng Liu (1)
  Zhenkuan Liu (4)
  
  1. Institute of Geology and Geophysics, Chinese Academy of Sciences, 100029, Beijing, China
  2. Institute of Geophysics, China Seismological Bureau, 100085, Beijing, China
  3. Institute of Deposition Resource, Chinese Academy of Geosciences, 100037, Beijing, China
  4. School of Exploration and Information, China University of Geosciences, 100083, Beijing, China
  
• ISSN：1869-1897

文摘

The fault belts in Sanjiang mainly include Jinshajiang-Honghe fault, Lancangjiang fault and Nujiang fault (called Sanjiang faults) in western Yunnan Province, China. By interpreting the wide-angle seismic reflection/refraction profile between Zhefang and Binchuan, which crosses Tengchong and Baoshan blocks in Dianxi (western Yunnan) tectonic zone, we reconstruct the crustal structure with seismic traveltime tomography for crustal P-wave velocity and the seismic scattering image for crustal seismic reflection structure. In this paper, we firstly present the crustal structure images of P-wave velocity and seismic reflection under the wide-angle seismic profile. These results demonstrate that, the crustal velocity structure and seismic reflection structure along the profile can be divided into 3 segments, and there is an obvious difference of crustal structure among the eastern, the western and the middle segment. Generally, crustal P-wave velocities in the Baoshan segment are 0.1-.2 km/s slower and seismic reflection amplitudes from Moho discontinuity are stronger than the other 2 segments. In the studied area, crustal thickness is about 40 km, and shows the thickening tendency from west to east along the profile. Additionally, it can be seen that there is one strong-amplitude seismic reflection event as bright points at the depths of 8-0 km, along the segment of 80-15 km of the profile (south-ward of Tengchong); and seismic reflection wave-field from Moho discontinuity varies obviously along the lateral direction. Finally, we make some discussions on the crustal thickening pattern in the Sanjiang fault belt, structural environment of earthquake development and the contact relationship between the Tengchong block, Banshan block and Luxi trough.