[1]WANG Xiaoshan,FENG Xiangdong,ZHAO Yingping.Characteristics of Crustal Stress Field in Beijing-Tianjin-Hebei Region[J].Journal of Seismological Research,2020,43(04):610-619.
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Journal of Seismological Research[ISSN 1000-0666/CN 53-1062/P] Volume:
43
Number of periods:
2020 04
Page number:
610-619
Column:
Public date:
2020-09-17
- Title:
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Characteristics of Crustal Stress Field in Beijing-Tianjin-Hebei Region
- Author(s):
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WANG Xiaoshan1; 2; FENG Xiangdong1; 2; ZHAO Yingping1
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(1.Hebei Earthquake Agency,Shijiazhuang 050021,Hebei,China)(2.Hebei Key Laboratory of Earthquake Dynamics,Sanhe 065201,Hebei,China)
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- Keywords:
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Beijing-Tianjin-Hebei region; focal mechanism solutions; damped inversion of stress tensor; crustal stress field
- CLC:
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P315.727
- DOI:
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- Abstract:
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Based on the values of scalar fault types,we classified the focal mechanism solutions of 2 187 small and medium earthquakes in the Beijing-Tianjin-Hebei region and its adjacent areas.The statistical results show that the main types of focal mechanisms are strike-slip and normal faulting,and the dominant direction of P-axis azimuth is NEE-EW and SWW-EW.Then we inverted the fine crustal stress field of 1°×1° grid in this region by MSATSI software package.The result shows that the dominant direction of the maximum principal compressive stress axis is NEE-EW direction,which is consistent with the dominant direction of the P-axis.The relative stress magnitude R of all grids were all less than 0.5,indicating the tensile property of the stress state in the Beijing-Tianjin-Hebei region.Moreover,the uncertainty range of the minimum principal compressive stress axis was relatively stable,indicating that the crustal stress field in the Beijing-Tianjin-Hebei region was under the control of a relatively unified extensional NNW-SSE direction.The axial direction of the best maximum principal compressive stress in the area in the north of 39°N,rotates at a certain angle from west to east,and the stress state inferred by the best maximum,medium,and minimum principal compressive stress axes had a normal fault-strike fault-normal fault transition process from west to east.The present tectonic stress field in the south area of 39°N remains stable,the optimal principal stress axis was in the NEE-SWW direction,and most of the stress states of the grid showed the strike-slip pattern.The inversion results of tectonic stress field in this paper are basically consistent with the results of active tectonic,GPS principal strain direction and fast wave polarization direction of shear wave splitting.