| 安第斯山中段现今地应力测量及地震相关性分析 |
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| 关键词:Andes Mountain insitu stress earthquake high pore pressure |
| 基金项目:国家自然科学基金项目(编号: 41404080);中国地质科学院地质力学研究所基本科研业务费项目(编号: DZLXJK201404) |
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| In Situ Stress Measurement in the Central Section of Andes and Its Relation to Seismicity |
| Located between the Nazca oceanic plate and the South American plate, Andes is one of the seismic extremely active areas in the world and is also known as the natural laboratory among seismologists and geologists. In this paper, the magnitude and orientation of in situ stress and its variation with depth were obtained for the first time by using the kilometer depth prospect borehole in the central section of Andes and the hydraulic fracturing in situ stress measurement method. The results show that the magnitude of in situ stress increases with increasing depth. The ranges of maximum horizontal principal stress, minimum horizontal principal stress and vertical stress are 12.38~34.47 MPa, 7.97~24.15 MPa and 6.81~26.10 MPa respectively. The relationships of three principal stresses are σH>σv≥σh, and the ratios of maximum horizontal principal stress to minimum horizontal principal stress are in the range of 1.43-1.66. The orientation of maximum horizontal principal stress is almost consistent with the focal mechanism solution and surface survey results. Based on the in situ stress measurement results, this paper deals with the in situ stress state and critical pore pressure of assumed epicenter depth (30 km) on the basis of Anderson fault theory and Coulomb friction criteria. The results show that high pore pressure might have been the major factor responsible for the frequent earthquakes in this area besides the continued subduction of Nazca oceanic plate. The results achieved by the authors not only provide the in situ stress measurements for the seismic mechanism, but also serve as important supplements to the World Stress Map database. |
| CAO Hui,SUN Dong-sheng,MENG Wen,ZHAO Wei-hua,WAN Chuan-chuan.2015.In Situ Stress Measurement in the Central Section of Andes and Its Relation to Seismicity[J].Acta Geoscientica Sinica,36(2):250-254. |
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