2013年甘肃岷县—漳县交界M_s6.6地震序列双差定位研究
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摘要
利用甘肃遥测台网2013年7月22日至9月22日的震相观测报告,对2013年7月22日07时45分甘肃省岷县漳县交界M_S 6.6地震的地震序列进行双差定位研究。结果表明,地震序列呈北西向分布,与临潭—宕昌断裂的走向基本一致,地震分布长度约10 km。震源深度剖面显示断层面向西南倾斜,浅部倾角较陡,深部略缓,表现为"铲形"逆冲断层的特征。余震区存在一条向西南延伸的余震带,与发震断层相交成y字型,推测可能是逆冲推覆构造中常见的反冲断层。
Using the seismic phase observation reports from Gansu remote monitoring networks from July 22 to September 22 in 2013,the earthquake sequences of the Minxian-Zhangxian M_S 6.6earthquake(occurred at 07:45 on July 22,2013) in Gansu Province are relocated by double difference algorithm.The results show that the earthquake sequences are distributed approximately 10 km in length in NW direction,which is basically consistent with the strike of the Lintan-Tanchang fault.According to the focal depth profiles,the fault planes dip to the northwest,and the dip angle is steep in the shallow crust and gentle in the deep crust,manifesting itself as a listric thrust fault.A southwestward tilt aftershock belt is revealed intersecting with the seismogenic fault with y-shape,which is speculated as a back thrust fault that often appears in a thrust fault system.
Using the seismic phase observation reports from Gansu remote monitoring networks from July 22 to September 22 in 2013,the earthquake sequences of the Minxian-Zhangxian M_S 6.6earthquake(occurred at 07:45 on July 22,2013) in Gansu Province are relocated by double difference algorithm.The results show that the earthquake sequences are distributed approximately 10 km in length in NW direction,which is basically consistent with the strike of the Lintan-Tanchang fault.According to the focal depth profiles,the fault planes dip to the northwest,and the dip angle is steep in the shallow crust and gentle in the deep crust,manifesting itself as a listric thrust fault.A southwestward tilt aftershock belt is revealed intersecting with the seismogenic fault with y-shape,which is speculated as a back thrust fault that often appears in a thrust fault system.
引文
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郑文俊,袁道阳,何文贵,等.甘东南地区构造活动特征:兼论岷县漳县M 6.6地震孕震机制[J].地球物理学报,2013a,56(12):4 058-4 071.
郑文俊,闵伟,何文贵,等.2013年甘肃岷县漳县6.6级地震震害分布特征及发震构造分析[J].地震地质,2013b,35(3):604-615.
Fang L H,Wu J P,Wang W L et al.Relocation of the mainshock and aftershock sequences of M_S 7.0 Sichuan Lushan earthquake[J].Chin Sci Bull,2013,58:3 451-3 459,doi:10.1007/s11434-013-6000-2.
Waldhauser F,Ellsworth W L.A double-difference earthquake location algorithm:Method and application to the Northern Hayward Fault,California[J].Bull Seismol Soc Amer,2000,90:1 353—1 368.
王兰民,吴志坚.岷县漳县6.6级地震震害特征及其启示[J].地震工程学报,2013,35(3):401-412.
许冲,徐锡伟,郑文俊,等.2013年甘肃岷县漳县6.6级地震触发滑坡及其构造分析[J].地震地质,2013,35(3):616-626.
杨智娴,陈运泰,郑月军,等.双差地震定位法在我国中西部地区地震精确定位中的应用[J].中国科学D辑:地球科学,2003,33(增刊):129~134.
郑文俊,袁道阳,何文贵,等.甘东南地区构造活动特征:兼论岷县漳县M 6.6地震孕震机制[J].地球物理学报,2013a,56(12):4 058-4 071.
郑文俊,闵伟,何文贵,等.2013年甘肃岷县漳县6.6级地震震害分布特征及发震构造分析[J].地震地质,2013b,35(3):604-615.
Fang L H,Wu J P,Wang W L et al.Relocation of the mainshock and aftershock sequences of M_S 7.0 Sichuan Lushan earthquake[J].Chin Sci Bull,2013,58:3 451-3 459,doi:10.1007/s11434-013-6000-2.
Waldhauser F,Ellsworth W L.A double-difference earthquake location algorithm:Method and application to the Northern Hayward Fault,California[J].Bull Seismol Soc Amer,2000,90:1 353—1 368.
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