| 首都圈地区震源机制解及现今构造应力场时空变化特征研究 |
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| 引用本文： | 樊文杰,崔效锋,胡幸平,陈佳维. 首都圈地区震源机制解及现今构造应力场时空变化特征研究[J]. 地震学报, 2019, 41(1): 33-45. DOI: 10.11939/jass.20180064 |
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| 作者姓名： | 樊文杰 崔效锋 胡幸平 陈佳维 |
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| 作者单位： | 1.中国昆明 650224 云南省地震局 |
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| 基金项目： | 云南省地震局青年地震科学基金（2017ZL12）和云南省地震局青年地震科学基金（2017ZL11）共同资助 |
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| 摘 要： | 基于2009年1月至2017年11月首都圈地区发生的8 061个地震事件的23 293条P波初动极性数据，采用改进的格点尝试法计算了首都圈地区单次地震的震源机制解和小震综合断层面解。在初步分析这些数据的基础上，利用计算得到的单次地震的震源机制解和搜集到的已有历史地震的震源机制解数据，运用线性反演法对首都圈地区构造应力场的时空变化特征进行了研究。结果显示:① 研究区的地震震源机制解类型以走滑型为主，正断型次之，这些地震震源机制解的P轴方位大都为ENE向和近EW向，与该地区的构造应力场方向基本一致，仅有个别地震的P轴方位为NNW向；② 首都圈地区的构造应力场具有较好的一致性和连续性，最大主应力轴方位由西部的ENE向至东部的近EW向呈现顺时针旋转的趋势，应力类型整体上为走滑型，这与以往的研究结果相一致；③ 通过与已有研究结果相比较认为:京西北地区现今构造应力场是相对稳定的，最大主应力轴未呈明显改变；唐山地区和北京地区的构造应力场（最大主应力轴）在1976年唐山地震前后可能发生了变化，唐山地震后一年至今（1977—2017年）是否发生变化，依据现有的计算结果尚不得而知，需要更多的研究来进一步验证.
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| 关 键 词： | 首都圈地区 震源机制解 构造应力场 时空变化特征 |
| 收稿时间： | 2018-05-15 |
Focal mechanism solutions and spatio-temporal variations of the present tectonic stress field in Capital Circle region |
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| Affiliation: | 1.Yunnan Earthquake Agency，Kunming 650000，China2.Institute of Crustal Dynamics，China Earthquake Administration，Beijing 100085，China |
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| Abstract: | Based on 23 293 P-wave polarities of 8 061 earthquakes occurred during the period from January 1, 2009 to November 30, 2017, we calculate the focal mechanism solutions of single earthquakes and composite fault plane solutions with improved grid point test method. On the basis of preliminary analysis on these data, using obtained focal mechanism solutions and the focal mechanism solutions of historical earthquakes, we discuss the spatio-temporal variation of the present tectonic stress field in Capital Circle region by linear inversion method. The result shows that the focal mechanism solutions are mainly of strike-slip type in the studied region and the second is normal-faulting type. The P axis azimuths of these focal mechanism solutions mostly trend ENE or almost EW, which is consistent with the tectonic stress field in the region; except that P axis azimuths of a few earthquakes are in NNW direction. The results by Michael’s inversion method show that tectonic stress field of Capital Circle region present good consistency and continuity. The orientation of maximum principal stress axis is in ENE to nearly EW direction from west to east. On a whole, the stress is of strike-slip type, which is consistent with the results of previous scholars. Comparison with the previous research results indicates that the present stress field in northwest of Beijing is in relatively stable state, and the maximum principal stress axis has no obvious variation. But for Tangshan region and Beijing region, the tectonic stress field probably exhibits some variations before and after the 1976 Tangshan earthquake. Whether there is any variations of maximum principal stress axis since the Tangshan earthquake （1977—2017） in the studied region is unknown according to present calculation results, which need to be further verified. |
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