赣南地区小震震源机制分析
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摘要
利用从震源向上射出的直达P、S波引起的地动位移振幅比求解震源机制,得到赣南及近邻地区58个ML2.0~4.2地震的震源机制解。对震源机制解P、T轴参数进行l0°间隔归一频数分析,得到如下结论:①本区地震断层以走滑型为主;②震源机制P轴方位主要分布在270°～330°间,平均方位为287°,P轴倾俯角以小于30°的近水平优势分布,这一结果与区域NWW-SEE水平挤压为特征的构造应力场相吻合。
Based on the amplitude ratios of ground displacement caused by upward direct wave P and S from focal,focal mechanism solutions of 58 ML2.0～4.0 earthquakes in the Southern Area of Jiangxi province and its adjacent areas are calculated.On the basis of analysis by 10° interval normalizational frequence on the parameters of P-axis and T-axis of these focal mechanism solutions,we draw two conclusions: 1) the earthquake faults in this area are mainly strike-slip faults;2) the P-axis orientation are mainly distributed from 270° to 330°,its averaged orientation is 287°,and the P-axis elevation angles are nearly horizontal distribution.The results are consistent with the regional NWW-SEE horizontal compressional tectonic stress field.
Based on the amplitude ratios of ground displacement caused by upward direct wave P and S from focal,focal mechanism solutions of 58 ML2.0～4.0 earthquakes in the Southern Area of Jiangxi province and its adjacent areas are calculated.On the basis of analysis by 10° interval normalizational frequence on the parameters of P-axis and T-axis of these focal mechanism solutions,we draw two conclusions: 1) the earthquake faults in this area are mainly strike-slip faults;2) the P-axis orientation are mainly distributed from 270° to 330°,its averaged orientation is 287°,and the P-axis elevation angles are nearly horizontal distribution.The results are consistent with the regional NWW-SEE horizontal compressional tectonic stress field.
引文
①范玉兰,林纪曾.华南地区近震走时表,1998.
[1]梁尚鸿,李幼铬,束沛镒,等.利用区域地震台网振幅比资料测定小震震源参数[J].地球物理学报,1984,7(3):247-257.
[2]林纪曾,李幼铬.粤东、闽南沿海小震震源参数的研究[J].地震学报,1991,13(4):420-429.
[3]胡新亮,刁桂苓,马瑾,等.利用数字地震记录的P,S波振幅比资料测定小震震源机制解的可靠性分析[J].地震地质,2004,26(2):347-354.
[4]付虹,王绍晋,龙晓帆,等.利用数字化速度波形和仿真位移波形资料求解震源机制解的比较[J].地震研究,2009,32(1):18-24.
[5]蒋维强,林纪曾,赵毅,等.华南地区的小震震源机制与构造应力场[J].中国地震,1992,8(1):36-42.
[6]李鸿吉,秦建业.缅甸弧及其周围地区的震源机制和现代应力场[J].地震学报,1994,16(4):463-47.
[1]梁尚鸿,李幼铬,束沛镒,等.利用区域地震台网振幅比资料测定小震震源参数[J].地球物理学报,1984,7(3):247-257.
[2]林纪曾,李幼铬.粤东、闽南沿海小震震源参数的研究[J].地震学报,1991,13(4):420-429.
[3]胡新亮,刁桂苓,马瑾,等.利用数字地震记录的P,S波振幅比资料测定小震震源机制解的可靠性分析[J].地震地质,2004,26(2):347-354.
[4]付虹,王绍晋,龙晓帆,等.利用数字化速度波形和仿真位移波形资料求解震源机制解的比较[J].地震研究,2009,32(1):18-24.
[5]蒋维强,林纪曾,赵毅,等.华南地区的小震震源机制与构造应力场[J].中国地震,1992,8(1):36-42.
[6]李鸿吉,秦建业.缅甸弧及其周围地区的震源机制和现代应力场[J].地震学报,1994,16(4):463-47.
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