CAP方法反演福建漳浦海域M_L 4.0级地震震源机制解
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摘要
选用福建数字地震台网宽频带记录,利用CAP方法反演福建漳浦海域2016年6月18日ML4.0级地震震源机制解。反演得到震级M_W为3.7,节面Ⅰ走向85°、倾角82°、滑动角-167°;节面Ⅱ走向353°、倾角77°、滑动角-8°;最佳深度分布于11 km附近。分析认为此次地震的发震断层为走滑型断层,东西向节面为断层面,节面走向与震中附近的滨海断裂走向存在差异,滨海断裂是发震构造的可能性较小,漳浦海域地震可能是横向构造断层活动的结果。
Using the broadband records of Fujian Regional Seismic Network, the paper inverts the focal mechanisms of the M_L 4.0 earthquake in Zhangpu sea area on June 18 th, 2016 by CAP method. The results show that the best pair of couple solution is 85°, 82° and-167° for strike, dip and rake angles respectively; the strike, dip and rake angles of the other nodal plane are 353°, 77°and-8° respectively; the moment magnitude was MW3.7, and the optimum focal depth is on 11 km nearby. The results show that the earthquake mechanism was a strike-slip faulting. East-West nodal plane is the seismogenic fault. The both strikes of the two nodal plane are significantly different with the strike of the Binhai zone fault, the earthquake may not occur on the Binhai zone fault, the Zhangpu Sea earthquake may be the result of lateral tectonic faulting.
Using the broadband records of Fujian Regional Seismic Network, the paper inverts the focal mechanisms of the M_L 4.0 earthquake in Zhangpu sea area on June 18 th, 2016 by CAP method. The results show that the best pair of couple solution is 85°, 82° and-167° for strike, dip and rake angles respectively; the strike, dip and rake angles of the other nodal plane are 353°, 77°and-8° respectively; the moment magnitude was MW3.7, and the optimum focal depth is on 11 km nearby. The results show that the earthquake mechanism was a strike-slip faulting. East-West nodal plane is the seismogenic fault. The both strikes of the two nodal plane are significantly different with the strike of the Binhai zone fault, the earthquake may not occur on the Binhai zone fault, the Zhangpu Sea earthquake may be the result of lateral tectonic faulting.
引文
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[2]曲均浩,刘瑞峰,李金,.CAP方法反演2014年山东乳山M4.2、M4.0地震震源机制解[J].地震工程学报.2014,36(4):1076-1080.
[3]段刚.CAP方法反演福建仙游ML5.0、ML4.5级地震震源机制解[J].地球物理学进展.2016,31(4):1432-1437.
[4]洪德全,王行舟,韩立波,等.用CAP方法研究安庆4.8级地震震源机制[J].中国地震,2011,27(2):207-214.
[5]彭利媚,魏娅玲.由ML≥4.0地震震源机制解推断四川理县黑水断裂构造特征[J].华南地震,2016,36(3):11-16.
[6]ZhaoLS,HelmbergerDV.SourceEstimationfrom Broadband Regional Seismograms[J].Bull Seis Soc Amer,1994,84(1):91-104.
[7]Zhu L P,Helmberger D V.Advancement in Source Estimation Techniques Using Broadband Regional Seismograms[J].Bull Seism Soc Amer,1996,86(5):1634-1641.
[8]郑勇,马宏生,吕坚,等.汶川地震强余震(MS≥5.6)的震源机制解及其与发震构造的关系[J].中国科学(D辑),2009,39(4):413-426.
[9]Mori J.1991.Estimates of velocity structure and source depth using multiple P waves from after Shocks of the1987 Elomor Ranch and Superstition Hils,California,earthquakes[J].Bull.Seismol.Soc.Am,1991,81(2):508-523.
[10]黄昭,王善雄.台湾海峡滨海断裂带的构造特征与活动性[J].大地测量与地球动力学,2006,26(3):16-22.
[11]詹文欢,孙宗勋,唐诚,等.华南滨海断裂带及其对台湾海峡地震的控制作用[J].热带海洋学报,2004,23(4):19-24.
[12]高金耀.台湾海峡及其两岸地震和地热特征[J].东海海洋,1992,10(2):14-28.
[13]马宗晋,王乾盈,徐杰.台湾海峡两岸横向构造的对比研究[J].中国科学(D辑),2002,32(6):441-451.
[14]周硕愚,帅平,张跃刚,等.中国大陆及其东南沿海现时地壳运动[J].自然科学进展,2000,10(3):273-277.
[15]史粦华,周峥嵘,鲍挺,等.福建及沿海地区地震活动力源探讨[J].地震,2006,26(2):104-113.