| 2018年5月松原MS5.7地震序列发震断层及应力场特征 |
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| 引用本文： | 李君,王勤彩,郑国栋,刘庚,周辉,周聪.2018年5月松原MS5.7地震序列发震断层及应力场特征[J].地震学报,2019,41(2):207-218. |
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| 作者姓名： | 李君 王勤彩 郑国栋 刘庚 周辉 周聪 |
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| 作者单位： | 中国西安 710054 中国地震局第二监测中心;中国北京 100036 中国地震局地震预测研究所;中国长春 130000 吉林省地震局 |
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| 基金项目： | 地震科技星火计划项目（XH18070，XH17060Y）、国家重点研发计划“鄂尔多斯活动地块边界带地震动力模型与强震危险性研究”子课题（2017YFC1500102）、中国地震局地震预测研究所基本科研业务费专项（2018IEF010203，2014IES010204，2015IES0404）联合资助 |
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| 摘 要： | 利用双差定位方法对2018年松原MS5.7地震序列中ML≥1.0地震重新定位，之后使用CAP方法求解松原MS5.7地震序列中强地震的震源机制解，再借助MSATSI软件包反演得到松原地区的区域应力场。综合分析以上研究结果得到如下结论:① 松原MS5.7地震序列发生在NW走向的第二松花江断裂与NE走向的扶余—肇东断裂交会处，将地震精定位结果沿两条断层走向作剖面分析，NW向剖面主轴长度约为5 km，震中分布均匀，NE向剖面主轴长度亦约为5 km，震中呈倾向NE的高倾角分布；② 该序列中的4次ML≥3.7地震的震源机制解具有良好的一致性:节面Ⅰ走向为NE向，节面Ⅱ走向为NW向，均为高倾角走滑断层。中强地震的震源机制节面解与第二松花江断裂性质基本一致，由此推断第二松花江断裂是本次松原地震的发震断层；③ 松原地区的主压应力方位角为N86°E，倾角为7°，主张应力方位角为N24°E，倾角为71°。松原地区的区域应力场既受到大尺度的板块构造运动的控制，又受到区域构造运动的影响。在太平洋板块对北东亚板块向西俯冲作用下，东北地区产生了近EW向的主压应力，受周边地质构造控制，松辽盆地内NE向断裂与NW向断裂交会处易发生走滑型地震，2018年松原MS5.7地震正是在这种构造作用控制下发生的中强地震。
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| 关 键 词： | 松原地震 双差定位 震源机制解 构造应力场 |
| 收稿时间： | 2018-07-25 |
Characteristics of seismogenic faults and stress fields of the Songyuan MS5.7 earthquake sequence in May 2018 |
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| Institution: | 1.The Second Monitoring and Application Center，China Earthquake Administration，Xi’an 710054，China2.Institute of Earthquake Forecasting，China Earthquake Administration，Beijing 100036，China3.Jilin Earthquake Agency，Changchun 130000，China |
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| Abstract: | In recent years, moderate-strong earthquakes in Songyuan area of Jilin Province are active. Studying the fault structure and stress field characteristics of the earthquake sequence in Songyuan area is of great significance for scientific understanding of the earthquake-preserving environment in Northeast China and earthquake prevention. The ML≥1.0 earthquakes are relocated by the method of double difference relocation, the focal mechanism solutions of the strong earthquakes are determined by the CAP method, and the stress field is determined by the FMSI method.According to the results, we realize that: ① The Songyuan MS5.7 earthquake sequence occurred at the intersection of the Second Songhuajiang fault trending NW and Fuyu-Zhaodong fault trending NE. The results of earthquakes relocation are analyzed along the two faults. The length of the NW axis is about 5 km, the same as to NE axis. The epicenters on the profile of NW axis have a high inclination distribution, while the NE axis is uniform. ② The focal mechanism solutions of four ML≥3.7 earthquakes are all of strike-slip type with high dip angles and good consistency: The strike of nodal plane Ⅰ is NE, and the other is NW. The focal mechanisms of the moderate-strong earthquakes are basically consistent with the Second Songhuajiang fault, and it is concluded that the Second Songhuajiang fault is the seismogenic fault of the Songyuan MS5.7 earthquake; ③ The principal compressive stress azimuth and the inclination angle of Songyuan area are N86°E and 7°, respectively, and the principal tensile stress azimuth and the inclination angle are N24°E and 71°, respectively. The regional stress field in Songyuan area is controlled by both large-scale plate tectonic movement and regional tectonic movement. Under the westward subduction of the Pacific Plate, the Northeast Asia Plate’s principal compressive stress near the EW direction is generated, which is controlled by the surrounding geological structure. The strike-slip type earthquake is prone to occur at the intersection of the NE-trending fault and the NW-trending fault in the Songliao basin, while the 2018 Songyuan MS5.7 earthquake is a moderate-strong earthquake that occurred under the control of such tectonic action. |
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