1996年5月3日内蒙古包头西M_S6.4级地震的震源机制研究
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摘要
利用地幔波波形拟合和P波初动符号联合反演的方法，估计了1996年5月3日内蒙古包头西MS6．4级地震的震源机制．得到节面1（40°，70°，－174°），节面2（308°，84°，－20°）。主压力轴P（-13．95×1017Nm，262°，19°），主张力轴T（15．66×1017Nm，356°，10°），中性轴N（B）（1．52×1017Nm，112°，69°）．地震形成左旋走滑兼弱倾滑断裂，断裂面较陡．据ML≥3.0级的余震分布、Ⅷ度区的烈度分布以及宏观震中与微观震中的相对位置推测，节面2可能与实际的地震破裂面相近．据宽频垂直向（BHZ）波形记录中SP与P的到时差估计，震源深度约为21Km．
The mechanism of Ms6.4 earthquake on May 3, 1996, at west Bac Ton, Nei Mongol, is estimated with a joint inversion method using mantle waveform fitting and P wave first inchon signs. Nodal plane l(40°, 70°,-174°), nodal plane 2(308°, 84°,-20°); principal compressive axis P(-13.95×1017Nm, 262°, 19°), principal extensional axis T(15.66×1017Nm, 356°, 10°), neutral axis N(B) (1.52×1017Nm, 112,69°) are obtained. The earthquake formed a left-lateral strike-slip and weak dipslip fault and the fault plane is steep. That nodal plane 2 may be near the actUal fault plane is inferred by the distribution of aftershocks with ML>3.0 and the distribution of earthquake intensity with degree m, as well as the relative position of macroscopic epicenter to the microcosmic one. That the source depth is about 21km was estimated by the bine differences betWeen sP and P arrival bine on BHZ channel.
The mechanism of Ms6.4 earthquake on May 3, 1996, at west Bac Ton, Nei Mongol, is estimated with a joint inversion method using mantle waveform fitting and P wave first inchon signs. Nodal plane l(40°, 70°,-174°), nodal plane 2(308°, 84°,-20°); principal compressive axis P(-13.95×1017Nm, 262°, 19°), principal extensional axis T(15.66×1017Nm, 356°, 10°), neutral axis N(B) (1.52×1017Nm, 112,69°) are obtained. The earthquake formed a left-lateral strike-slip and weak dipslip fault and the fault plane is steep. That nodal plane 2 may be near the actUal fault plane is inferred by the distribution of aftershocks with ML>3.0 and the distribution of earthquake intensity with degree m, as well as the relative position of macroscopic epicenter to the microcosmic one. That the source depth is about 21km was estimated by the bine differences betWeen sP and P arrival bine on BHZ channel.
引文
1马淑田,姚振兴,纪晨1996年3月19日新疆伽师MS6.9地震的震源机制解以及相关问题研究.地球物理学报,1997,40(6)782-790
2 Gilert E,Dziewonski A M.An application of normal mode theory to the retrieval of stfllCtural of:structural parameters and source mechanisms from seismic spectra.Philos Trans R dec Lonndon 1975,A278:187-269
3姚振兴,郑天愉,曹柏如,王凯.用P波波形资料测定中强地震震源过程的方法.地球物理学进展,1991,6(4);1-26
4纪晨.地震波传播及波形反演[硕士论文],北京:中国科学院地球物理研究所, 1994, 18-31
5Aki K Richards G Quanhtahve Seismology, Vol II,唐美华,吴宁远译,姚振兴校.北京:地震出版社,1980.272-273
6AKi K. Richards G.Quanitative Seismology.Vol.I, W H. Freeman, San Francisco,105-119
7张诚,修济刚,邱同芝,雷可夫VI,曲克信全球强震震源机制.北京:万国学术出版社,1993.1-2
2 Gilert E,Dziewonski A M.An application of normal mode theory to the retrieval of stfllCtural of:structural parameters and source mechanisms from seismic spectra.Philos Trans R dec Lonndon 1975,A278:187-269
3姚振兴,郑天愉,曹柏如,王凯.用P波波形资料测定中强地震震源过程的方法.地球物理学进展,1991,6(4);1-26
4纪晨.地震波传播及波形反演[硕士论文],北京:中国科学院地球物理研究所, 1994, 18-31
5Aki K Richards G Quanhtahve Seismology, Vol II,唐美华,吴宁远译,姚振兴校.北京:地震出版社,1980.272-273
6AKi K. Richards G.Quanitative Seismology.Vol.I, W H. Freeman, San Francisco,105-119
7张诚,修济刚,邱同芝,雷可夫VI,曲克信全球强震震源机制.北京:万国学术出版社,1993.1-2
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