| 内蒙古敖汉旗震群的微震匹配定位及其发震断层研究 |
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| 引用本文： | 张珂,张帆,张晖,王鑫,郝美仙,翟浩.内蒙古敖汉旗震群的微震匹配定位及其发震断层研究[J].地震学报,2022,44(4):594-607. |
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| 作者姓名： | 张珂 张帆 张晖 王鑫 郝美仙 翟浩 |
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| 作者单位： | 中国呼和浩特 010050 内蒙古自治区地震局 |
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| 基金项目： | 中国地震局地震科技星火计划（XH20014）和内蒙古自治区地震局局长基金（2020JC07，2022（ZD）TM02）联合资助 |
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| 摘 要： | 内蒙古敖汉旗地区在2018—2019年间曾发生多次小震丛集活动，不同地震事件的波形记录易相互交叠，导致地震目录缺失。针对以上问题，采用匹配定位（Match & Locate）方法，对台网遗漏地震进行识别、检测与定位，并通过CAP方法反演敖汉旗震群最大地震的震源机制解，利用匹配定位后的小震分布定量地拟合发震断层面参数，从而综合判定敖汉旗震群的发震断层面几何形态和发震构造。结果显示:通过匹配定位方法共识别、定位405个小震事件，是原有地震目录事件的5.4倍，震群主体沿NW?SE向展布于红山—八里罕断裂与赤峰—开源断裂相交区域的东侧，震源深度集中于8—10 km。断层拟合结果和最大地震震源机制解表明敖汉旗震群的发震构造应是一条左旋走滑型隐伏正断层，断层面走向为157°，倾角为84°。综合分析红山—八里罕断裂和赤峰—开源断裂的断层性质和活动特征，认为敖汉旗震群的发震断层可能是这两条深大断裂在不断活动中相互作用而形成。
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| 关 键 词： | 敖汉旗震群 匹配定位 震源机制 断层面拟合 |
| 收稿时间： | 2021-03-22 |
Matching location for small events and seismogenic fault of Aohanqi earthquake swarm of Inner Mongolia |
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| Institution: | Earthquake Agency of Inner Mongolia Automatic Region，Hohhot 210014，China |
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| Abstract: | In Aohanqi area of Inner Mongolia, there occurred several clusters of small earthquakes during 2018?2019 and the waveforms of different earthquakes are overlapped with each other, which leads to the incompleteness of earthquake catalog. In order to solve this problem, we adopt the match and locate （M&L） method to identify, detect and locate the missing events in the catalogs, and then the focal mechanism solution of the largest event is analyzed by the CAP （cut and paste） method. The matched and located small earthquakes are used to fit parameters of seismogenic fault plane of the largest earthquake so as to determine the geometry of fault plane and seismogenic structure of Aohanqi earthquake swarm. The results show that by using the M&L method, we identified and located 405 small earthquake events, which are 5.4 times as much as the number of the original detected earthquakes, and the earthquake swarm extended predominately along the direction of NW?SE in the east of the intersection area between Hongshan-Balihan fault and Chifeng-Kaiyuan fault with focal depth mainly concentrating on 8?10 km. Besides, according to the fault fitting result of small earthquakes and the focal mechanism of the largest earthquake, it is concluded that the seismogenic structure of Aohanqi earthquake swarm is a concealed normal fault with sinistral strike-slip characteristics, which has a strike of 157° and a dip of 84°. Combined with the fault properties and activity characteristics of the Hongshan-Balihan fault and the Chifeng-Kaiyuan fault, it is deduced that the seismogenic fault of Aohanqi earthquake swarm may be formed by the interaction of the two deep and large faults in the continuous activities. |
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