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《地震研究》[ISSN:1000-0666/CN:53-1062/P]

卷:

43

期数:

2020年04期

页码:

610-619

栏目:

出版日期:

2020-09-17

文章信息/Info

Title:

Characteristics of Crustal Stress Field in Beijing-Tianjin-Hebei Region

作者:

王晓山¹; 2; 冯向东¹; 2; 赵英萍¹

(1.河北省地震局,河北 石家庄 050021; 2.河北省地震动力学重点实验室,河北 三河 065201)

Author(s):

WANG Xiaoshan¹; 2; FENG Xiangdong¹; 2; ZHAO Yingping¹

(1.Hebei Earthquake Agency,Shijiazhuang 050021,Hebei,China)(2.Hebei Key Laboratory of Earthquake Dynamics,Sanhe 065201,Hebei,China)

关键词:

京津冀地区;  震源机制;  应力张量阻尼反演;  地壳应力场

Keywords:

Beijing-Tianjin-Hebei region;  focal mechanism solutions;  damped inversion of stress tensor;  crustal stress field

分类号:

P315.727

DOI:

-

摘要:

基于标量断层类型值,对京津冀地区及邻区2 187个中小地震震源机制解进行分类,统计结果显示研究区震源机制类型以走滑断层和正断层为主,P轴优势方位为NEE—EW和SWW—EW向; 采用MSATSI软件包反演该区1°×1°网格的精细地壳应力场,结果表明:最大主压应力轴最优解的优势方向为NEE—EW向,与P轴优势方位一致; 所有网格的相对应力大小R值均小于0.5,表明京津冀地区应力状态偏拉张性质,而且最小主压应力轴的不确定度变化范围相对稳定,表明现今京津冀地区地壳应力场处于一个相对统一的NNW—SSE向的拉张作用控制下。39°N以北地区最大主压应力轴方位最优解显示一定角度的偏转,同时最大、中等、最小主压应力轴最优解推断的应力状态由西向东存在一个正断层—走滑断层—正断层的转换过程; 而39°N以南地区的现今构造应力场保持稳定,最优主压应力轴呈NEE—SWW向,大部分网格应力状态显示走滑型。构造应力场的反演结果与活动构造、GPS主应变方向和剪切波分裂的快波偏振方向等相关研究结果基本一致。

Abstract:

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.

参考文献/References:

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备注/Memo

备注/Memo:

收稿日期:2020-03-17
基金项目:河北省技术创新引导计划项目(19975412D)和河北省地震局地震科技星火重点项目(DZ20180319009,DZ20160621078)联合资助.

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更新日期/Last Update: 2020-09-17