SEISMOLOGY AND GEOLOGY ›› 2018, Vol. 40 ›› Issue (6): 1380-1389.DOI: 10.3969/j.issn.0253-4967.2018.06.013

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THE ANALYSIS OF VERTICAL MOTION CHARACTERISTICS IN YUNNAN AREA BASED ON PRECISE LEVELING

SU Guang-li, CHANG Liu, XU Ming-yuan   

  1. First Crust Deformation Monitoring and Application Center, China Earthquake Administration, Tianjin 300180, China
  • Received:2017-11-01 Revised:2018-06-13 Online:2018-12-20 Published:2019-01-18

基于精密水准的云南地区垂直运动特征分析

苏广利, 畅柳, 许明元   

  1. 中国地震局第一监测中心, 天津 300180
  • 作者简介:苏广利,男,1989年生,工程师,主要从事大地形变测量与工程形变监测技术与应用,E-mail:0suguangli@163.com。
  • 基金资助:
    中国地震局监测、预测、科研三结合课题(CEA-JC/3JH173707)和中国地震局第一监测中心科技创新主任基金资助项目(FMC2016005)共同资助

Abstract: In this study, vertical deformation of different regions of Yunnan area in 1993-2013, 2001-2006, 2011-2017 is obtained using observational data of precise leveling. The results show that:1) In the whole, Yunnan area exhibits uplifting in the east of Yunnan and subsiding in the south of Yunnan, which is well consistent with the current horizontal velocity field obtained by GPS. In the east of Yunnan, southeastward horizontal velocity at the east boundary of Sichuan-Yunnan block is significantly decreased, which indicates extrusion deformation. This result is in accordance with the result that there is uplift in the east of Yunnan with precise leveling data. GPS velocity field rotates clockwise at Eastern Himalayan Syntaxis, therefore east-west extension is formed in central and southern Yunnan, which coincides with crustal subsidence observed by precise leveling. 2)The vertical movement in the northwest of Yunnan mainly exhibits the succession movement of basin subsidence and mountain uplift, in which, in the rift zone, Chenghai Basin, Qina Basin, Binchuan Basin and Midu Basin distributed along Chenghai Fault are all in the sinking state and the sinking velocity of Binchuan Basin located in the end of the sinistral strike-slip Chenghai Fault is the maximum. The sinking velocity of Dali Basin distributed along Honghe Fault is approximately 0.5mm/a and the sinking velocity of Midu Basin is approximately 1mm/a under the comprehensive action of right-lateral Honghe Fault and left-lateral Chenghai Fault. On the northwest boundary of the fault zone, the vertical movement of the basins (Lijiang Basin, Jiangchuan Basin)under the control of the nearby Lijiang-Jianchuan Fault is not obvious and the nearby mountain area exhibits uplift. 3)In the Honghe Fault, the southern region still possesses strong activity. Seeing from the leveling profile and vertical deformation field, the Honghe Fault still possesses the significance of block boundary fault and strong activity. GPS velocity field reveals that the southeast movement velocity of the Sichuan-Yunnan rhombic block is rapidly decreased near Xiaojiang Fault and the earth's crust is shortened and deformed. In the vertical deformation field, the uplift is formed near Xiaojiang Fault and there is obvious vertical deformation gradient. 4)Notably, deformation contour in the junction of Qujiang Fault and Xiaojiang Fault is characterized by four quadrant distribution, which indicates the possibility of earthquake.

Key words: precise leveling, Yunnan, fault, vertical movement rate

摘要: 文中利用1993—2017年多期精密水准观测资料获取了云南不同区域1993—2013年、2001—2016年、2011—2017年的垂直形变场。结果表明云南地区整体表现为滇东压缩区隆升、滇中南拉分区下沉的运动形态,与GPS水平速度场吻合较好。红河断裂和小江断裂是2条重要的地壳垂向运动分割线,其中小江断裂两侧差异运动速率达5mm/a;红河断裂南西盘下沉,北东盘隆升;从水准剖面和垂直形变场来看,红河断裂仍具有块体边界断裂的意义,仍存在较强的活动性。滇西北地区以继承性运动为主,其中沿程海断裂分布的程海盆地、期纳盆地、宾川盆地,沿红河断裂分布的大理盆地、弥渡盆地均为下沉状态;丽江-剑川断裂所控制的丽江盆地、剑川盆地垂向运动不明显,附近山区表现为隆升。值得注意的是在曲江断裂、小江断裂交会处形变梯度较大,等值线有四象限分布特征,有孕育地震的可能。

关键词: 精密水准, 云南, 断裂, 垂直运动速率

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