根据余震资料求解2003年伽师M_S6.8地震断层面的研究
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摘要
大地震发生后,大量余震在断层面及其附近发生。余震震源位置的空间分布可以较为精确地勾画出断层面的形状和位置。假定地震发震断层可以用一个平面来模拟,且设大多数余震发生在这个断层面的附近,则可以通过余震震源位置参数来求解发震断层的走向、倾角及位置。本文首次采用2003年2月24日新疆伽师MS6.8地震后精确定位的小震资料反演了伽师地震断层面的走向和倾角,并以此为基础求得了该断层面上的滑动角。并根据小震丛集性原则,尝试用数学方法先对反演所采用的数据进行筛选再进行反演,所得的结果精确程度更高,验证了这种做法的有效性。
A lot of aftershocks will happen on and around the fault plane after big earthquakes.The spatial distribution of the aftershocks' position can precisely sketch the shape and position of the fault plane.Assuming that seismic fault can be simulated as a plane and most aftershocks would happen nearly around the fault plane,we can use the parameters of the aftershocks' position to estimate the strike,dip and position of the fault plane.We firstly use the aftershocks of the earthquake of MS6.8 occurring in Jiashi region,Xinjiang Uygur Autonomous Region on February 24,2003 to estimate the strike,dip and rake of the fault plane.According to the principle of the cluster of small earthquakes,we also try to use mathematical methods to screen data before inversing,and the more accurate inversion results validate the effectiveness of the proposed method.
A lot of aftershocks will happen on and around the fault plane after big earthquakes.The spatial distribution of the aftershocks' position can precisely sketch the shape and position of the fault plane.Assuming that seismic fault can be simulated as a plane and most aftershocks would happen nearly around the fault plane,we can use the parameters of the aftershocks' position to estimate the strike,dip and position of the fault plane.We firstly use the aftershocks of the earthquake of MS6.8 occurring in Jiashi region,Xinjiang Uygur Autonomous Region on February 24,2003 to estimate the strike,dip and rake of the fault plane.According to the principle of the cluster of small earthquakes,we also try to use mathematical methods to screen data before inversing,and the more accurate inversion results validate the effectiveness of the proposed method.
引文
[1]黄媛,杨建思,张天中.2003年新疆巴楚-伽师地震序列的双差法重新定位研究[J].地球物理学报,2006,49(1):162-169.
[2]张云峰,王海涛,徐锡伟,等.2003年2月24日新疆巴楚-伽师6.8级地震[J].国际地震动态,2003,291:1-10.
[3]王鸣,王培德.1989年10月18日大同—阳高地震的震源机制和发震构造[J].地震学报,1992,14(4):407-415.
[4]万永革,沈正康,刁桂苓,等.利用小震分布和区域应力场确定大震断层面参数方法及其在唐山地震序列中的应用[J].地球物理学报,2008,51(3):793-804.
[5]万永革,吴忠良,周公威,等.根据震源的两个节面的走向角和倾角求滑动角[J].地震地磁观测与研究,2000,21(5):26-30.
[6]陈华根,吴健生,王家林,等.模拟退火算法机理研究[J].同济大学学报(自然科学版),2004,32(6):802-805.
[7]马在田.计算地球物理学概论[M].上海:同济大学出版社.1997:405-413.
[8]高国英、聂晓红,夏爱国.2003年伽师6.8级地震序列特征和震源机制的初步研究[J].中国地震,2004,20(2):179-186.
[9]王卫民,李丽,赵连锋,等.2003年2月24日新疆伽师MS6.5级地震震源破裂过程研究[J].地球物理学报,2005,48(2):343-351.
[10]Shen Z K,Sun J B,Zhang P Z,et al.Slip maxima at fault junctions and rupturing of barriers duringthe 2008Wenchuan earthquake[J].Nature geoscience,2009,718-724.
[2]张云峰,王海涛,徐锡伟,等.2003年2月24日新疆巴楚-伽师6.8级地震[J].国际地震动态,2003,291:1-10.
[3]王鸣,王培德.1989年10月18日大同—阳高地震的震源机制和发震构造[J].地震学报,1992,14(4):407-415.
[4]万永革,沈正康,刁桂苓,等.利用小震分布和区域应力场确定大震断层面参数方法及其在唐山地震序列中的应用[J].地球物理学报,2008,51(3):793-804.
[5]万永革,吴忠良,周公威,等.根据震源的两个节面的走向角和倾角求滑动角[J].地震地磁观测与研究,2000,21(5):26-30.
[6]陈华根,吴健生,王家林,等.模拟退火算法机理研究[J].同济大学学报(自然科学版),2004,32(6):802-805.
[7]马在田.计算地球物理学概论[M].上海:同济大学出版社.1997:405-413.
[8]高国英、聂晓红,夏爱国.2003年伽师6.8级地震序列特征和震源机制的初步研究[J].中国地震,2004,20(2):179-186.
[9]王卫民,李丽,赵连锋,等.2003年2月24日新疆伽师MS6.5级地震震源破裂过程研究[J].地球物理学报,2005,48(2):343-351.
[10]Shen Z K,Sun J B,Zhang P Z,et al.Slip maxima at fault junctions and rupturing of barriers duringthe 2008Wenchuan earthquake[J].Nature geoscience,2009,718-724.
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