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现代地质 ›› 2017, Vol. 31 ›› Issue (05): 900-910.

• 川藏铁路沿线重大地质灾害与工程地质问题 • 上一篇    下一篇

西藏林芝地应力测量监测与尼泊尔MS8.1级强震远场响应分析

张鹏1,2(), 曲亚明3, 郭长宝1,2(), 丰成君1,2, 孟文1,2, 范玉璐4, 谭成轩1,2, 王磊5   

  1. 1.中国地质科学院 地质力学研究所,北京 100081
    2.国土资源部新构造运动与地质灾害重点实验室,北京 100081
    3.云南省交通规划设计研究院,云南 昆明 650051
    4.中国地质大学(北京) 工程技术学院,北京 100083
    5.福建省闽东南地质大队,福建 泉州 362011
  • 收稿日期:2016-10-12 修回日期:2017-05-10 出版日期:2017-10-10 发布日期:2017-11-06
  • 通讯作者: 郭长宝,男,博士,1980年出生,地质工程专业,副研究员,主要从事工程地质与地质灾害方面的研究。Email: guochangbao@163.com。
  • 作者简介:张鹏,男,助理研究员,1986年出生,地质工程专业,主要从事地应力测量与监测、地壳稳定性评价等研究工作。Email:zhangpeng0713@163.com
  • 基金资助:
    中国地质调查局项目(12120113038000);中国地质调查局项目(DD20160271);中国地质调查局项目(1212010914025);中国地质调查局项目(DD20160267);中国地质调查局项目(12120113012100)

Analysis of In-situ Stress Measurement and Real-time Monitoring Results in Nyching of Tibetan Plateau and Its Response to Nepal MS8.1 Earthquake

ZHANG Peng1,2(), QU Yaming3, GUO Changbao1,2(), FENG Chengjun1,2, MENG Wen1,2, FAN Yulu4, TAN Chengxuan1,2, WANG Lei5   

  1. 1. Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China
    2. Key Laboratory of Neotectonic Movement and Geohazard, Ministry of Land and Resources, Beijing 100081, China
    3. Yunnan Provincial Communication Planning and Design Institute, Kunming,Yunnan 650051,China
    4. School of Engineering and Technology, China University of Geosciences, Beijing 100083, China
    5. Southeastern Fujian Geological Party, Quanzhou,Fujian 362011, China
  • Received:2016-10-12 Revised:2017-05-10 Online:2017-10-10 Published:2017-11-06

摘要:

为查明川藏铁路林芝段现今地应力状态和附近主要断裂运动学和动力学活动特征,在西藏林芝北侧开展了300 m深度钻探工程和随深度系统水压致裂现今原位地应力测量与压磁法地应力实时监测工作。原地应力测量结果表明:(1)三个主应力大小之间关系为SH>ShSV,表明区域构造作用水平应力起主导作用,易于发生逆断活动;(2)现今最大水平主应力方向为北北东向,反映区域内北东—近南北向断裂带现今活动具有顺时针走滑的特征;(3)基于实测数据得到剪应力相对大小μm=0.11~0.23,反映了该区域应力积累较低,区域内断层活动的危险性较小。地应力实时监测结果表明2015年尼泊尔MS8.1级强震在该地应力实时监测站点具有显著的远场效应:(1)尼泊尔地震前,最大与最小水平主应力值分别增加了0.35 MPa和0.24 MPa,最大水平主应力方向基本保持不变;(2)尼泊尔地震时同震应力变化表明,地震导致最大与最小水平主应力值分别减小了0.05 MPa和0.04 MPa,最大水平主应力方向基本保持不变;(3)尼泊尔地震4个月后,最大水平主应力减小了0.05 MPa,而最小主应力增加了0.01 MPa,最大水平主应力方向基本保持不变。基于钻孔原地应力测量与实时监测数据分析尼泊尔地震前、震时、震后该站点地应力变化情况,对于区域内断裂活动、地震危险性、地壳稳定性等研究具有重要意义。

关键词: 原位地应力测量, 地应力实时监测, 地震危险性, 尼泊尔MS8.1级地震

Abstract:

To explore the in-situ stress in the fracture belt and its present activity, the authors gathered data from hydraulic fracturing for in-situ stress measurement and from piezomagnetic method for monitoring relative magnitude of in-situ stress along the drilling hole with total depth of 300 meters located in a granite-rich region in the northern part of Nyching, Tibet. The measurements of in-situ stress indicate the relationship of SH>Sh≥SV, and the structure features of shallow earth’s crust rock formation reveal that current horizontal principal stresses play a leading role in reverse fault activity. Moreover, the measured maximum principal in-situ stress strikes in NNE direction, reflecting present compressive properties with dextral slip activity of faulting to north-east and near-south-north trend. Calculated through measured principal stresses, the magnitudes of feature parameters (μm) are obtained to be in the range of 0.11 to 0.23, which reflect a lower-stress accumulative capability of the regional crust and inactivity of fault movement in this area. Although the direction of the maximum horizontal principal stress remains basically unchanged in the occurrence of Nepal MS8.1 earthquake, the stress-monitoring results show that before the earthquake the values of the maximum and minimum horizontal principal stresses increase in 0.35 MPa and 0.24 MPa, respectively; during the earthquake for the co-seismic effect the reduced values are 0.05 MPa and 0.04 MPa, respectively; while four months later after the earthquake the maximum horizontal principal stress is reduced by 0.05 MPa, and the minimum principal stress increases by 0.01 MPa. Based on the in-situ stress measuring and real-time monitoring results while the earthquakes happen, the change of stress fields can be investigated to understand the activity of regional faults and it is much significant for the study of seismic risk and crustal stability.

Key words: in-situ stress measurement, in-situ stress monitoring, seismic hazard, Nepal MS8.1 earthquake

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