| 摘要: |
| 首先通过模板匹配方法检测无为震群活动期间目录遗漏的地震事件，共识别出5次遗漏地震事件，震级为ML0.5～1.2，得到了更为完整的地震目录；然后基于波形互相关震相检测技术标定震相到时，进而采用双差定位方法进行精定位，精定位后震群分布更加集中，未见明显的优势方位分布；采用Snoke方法计算震级较大地震的震源机制，结果表明，此次震群为NEE向的水平挤压与NNE向的水平拉张应力场作用下具逆冲分量的走滑型地震活动，严家桥-枫沙湖断裂可能为其发震构造；最后，计算了震群序列的视应力，结果显示，视应力和扣除震级影响后的差视应力随着震群序列的衰减逐渐恢复，因此，分析认为，随着无为震群序列的衰减，震源区发生更大地震的可能性不大。 |
| 关键词: 无为MS3.0震群 遗漏地震检测 双差定位 震源机制解 视应力 |
| DOI： |
| 分类号:P315 |
| 基金项目:中国地震局地震科技星火计划项目（XH16017Y）、中国地震局2017年震情跟踪定向工作任务（2017010107）共同资助 |
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| Research on seismogenic structure and aftershock tendency of the Wuwei MS3.0 earthquake swarm sequence, Anhui in 2016 |
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Ni Hongyu1,2, Liu Zemin1, Hong Dequan1,2, Zhao Peng1, Wang Xiaoli1
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1.Earthquake Administration of Anhui Province, Hefei 230031, China;2.Mengcheng National Geophysical Observatory, Mengcheng 230036, Anhui, China
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| Abstract: |
| We firstly used matched filter technique to detect missing earthquakes in the Wuwei MS3.0 earthquake swarm sequence,and 5 missing earthquakes during ML0.5-1.2 were detected,which led to a more complete catalogue. Then waveform cross-correlation phase detection technique was used to recalibrate P- and S-wave phase arrival times,and further relocate the earthquakes in the swarm using the double-difference method based on recalibrated phase arrival times,which shows the relocated epicenters were distributed in more concentrated locations and without obvious predominant directions. The focal mechanisms of stronger earthquakes of the swarm were calculated by using the Snoke methods,indicating this earthquake swarm sequence was caused by strike-slip faulting with thrust component under the action of horizontally compressed nearly in NEE direction and horizontally dilated nearly in NNE direction. The Yanjiaqiao-Fengshahu fault is likely to be seismogenic structure of the Wuwei MS3.0 earthquake swarm sequence. Apparent stress of the Wuwei MS3.0 earthquake swarm sequence was calculated,which shows that apparent stress and variation of the apparent stress eliminated the effect of the magnitude recovered gradually with the attenuation of the earthquake swarm sequences,so we refer that larger earthquake may be unlikely to occur around the Wuwei epicenter. |
| Key words: Wuwei earthquake swarm sequence Missing earthquakes detection Double-difference earthquake location Focal mechanism solutions Apparent stress |
