| 太原盆地应力场演化与强震关系的数值模拟研究 |
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| 引用本文： | 李平恩,廖力,刘盼.太原盆地应力场演化与强震关系的数值模拟研究[J].地球科学,2017,42(9):1623-1636. |
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| 作者姓名： | 李平恩 廖力 刘盼 |
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| 作者单位： | 1.中国地震局地球物理研究所, 北京 100081 |
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| 基金项目： | 中国地震局地球物理研究所基本科研业务费专项No.DQJB14C06国家自然科学基金项目No.41674105地震行业科研专项No.201408014 |
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| 摘 要： | 近年来，太原盆地内尽管没有强震发生，小震却异常活跃，而研究太原盆地构造应力场的分布和演化规律的工作比较少.采用有限元数值方法，综合考虑区域地质构造差异、主要活动断裂带、地形起伏和岩石圈分层结构，引入深部速度结构，建立包含太原盆地在内的山西地区三维粘弹性模型.以GPS观测值和最大主压应力方向测量值为约束条件，重建研究区现今构造背景应力场.在此基础上，依次模拟了自公元512年以来太原盆地6级以上和山西地震带7级以上历史强震序列.计算结果显示，太原盆地内的3次6级以上历史地震均落在应力场增加值大于0.01 MPa的区域，盆地近年来小震空间分布与现今应力增加值大于0.01 MPa的区域有较好的对应关系.研究表明:山西地震带内历史强震序列和长期构造加载对太原盆地内3次历史强震均有促进作用，太原盆地的地震活动性明显受区域当前应力水平的控制.
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| 关 键 词： | 太原盆地 应力场演化 强震间相互关系 地震活动性 数值模拟 |
| 收稿时间： | 2016-12-28 |
Numerical Simulation of Relationship between Stress Field Evolution and Historical Strong Earthquakes in Taiyuan Basin |
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| Abstract: | In recent years, although no strong earthquakes occurred in Taiyuan basin, small earthquakes were very active. However, the research on the distribution and evolution of tectonic stress field in Taiyuan basin is very little. The 3-D viscoelastic finite element model of Shanxi area including Taiyuan basin is built by applying the finite element numerical method in this paper. In addition, the difference of regional geological structure, the main active fault zone, irregular topography and layered lithosphere structure synthetically, as well as the seismic velocity structure of the crust and mantle, are considered when building the model. Moreover, the present tectonic background stress field in the research area is reconstructed by the constraint of the observed values of GPS and direction of the maximum principal compressive stress. On these bases, the historical strong earthquake sequences with M ≥ 6 in Taiyuan basin and with M ≥ 7 in Shanxi seismic zone since AD 512 are simulated, respectively. The calculated results illustrate that the three historical strong earthquakes in Taiyuan basin are all located in the area where stress field increased more than 0.01 MPa, and the spatial distribution of small earthquakes in recent years has a good correlation with the present stress field change greater than 0.01 MPa. The results show that the historical strong earthquake sequence in Shanxi seismic zone and long-term tectonic stress loading both promoted the three historical strong earthquakes in Taiyuan basin. The present seismic activity of Taiyuan basin is obviously controlled by the current stress level in the area. |
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