2011年1月安徽安庆M_S4.8地震震源区三维速度结构与发震构造讨论
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摘要
2011年1月19日安徽安庆发生MS4.8地震,本次地震发生在下扬子地块长江沿线前陆变形带。震后现场工作队调查汇总了建筑物破坏情况,计算得出较为精确的烈度分布。采用FOCMEC方法计算了主震震源机制解,并利用安徽地震台网对本次地震主余震的定位结果,结合地震层析成像技术对震源区地壳三维速度结构的成像结果进行分析,同时参考烈度分布的椭圆长轴优势方向,得出NE向的宿松-枞阳断裂可能是本次地震的发震断层的结论。
The Anqing MS4.8 earthquake occurred on January 19,2011,and the epicenter lies in foreland deformation belt along the Yangtze River in Yangtze plate.After the earthquake,the field work team surveyed and summarized the building damage data,calculating intensity distribution,obtaining comparatively reliable intensity distribution graph.The focal mechanisms of main shock are calculated tentatively using digital seismic wave data in some provincial digital seismic networks based on the FOCMEC program,combing the first motion of P,SV and SH waves with their amplitude ratios.The comprehensive analysis of the major aftershock location result of Anhui seismic network,together with the focal region crust three-dimensional velocity structural images by the seismic tomographic technology,and the intensity distribution of elliptic long axis advantage direction reveals that NE trend Susong-Zongyang fault may be the causative fault of Anqing earthquake.
The Anqing MS4.8 earthquake occurred on January 19,2011,and the epicenter lies in foreland deformation belt along the Yangtze River in Yangtze plate.After the earthquake,the field work team surveyed and summarized the building damage data,calculating intensity distribution,obtaining comparatively reliable intensity distribution graph.The focal mechanisms of main shock are calculated tentatively using digital seismic wave data in some provincial digital seismic networks based on the FOCMEC program,combing the first motion of P,SV and SH waves with their amplitude ratios.The comprehensive analysis of the major aftershock location result of Anhui seismic network,together with the focal region crust three-dimensional velocity structural images by the seismic tomographic technology,and the intensity distribution of elliptic long axis advantage direction reveals that NE trend Susong-Zongyang fault may be the causative fault of Anqing earthquake.
引文
安徽省地质矿产局,1987,安徽省区域地质志,北京:地质出版社。
车自成、刘良、罗金海等,2002,中国及其邻区区域大地构造学,395～413,北京:科学出版社。
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刘杰、郑斯华、康英等,2004,利用P波和S波的初动和振幅比计算中小地震的震源机制解,地震,24(1),19～26。
王椿镛、张先康、陈步云等,1997a,大别造山带地壳结构研究,中国科学(D辑),27(3),221～226。
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徐佩芬、刘福田、王清晨等,2000,大别-苏鲁碰撞造山带的地震层析成像研究:岩石圈三维速度结构,地球物理学报,43(3),377～385。
朱光、徐嘉炜、刘国生等,1998,下扬子地区沿江前陆盆地形成的构造控制,地质论评,44(2),120～129。
周龙泉、刘福田、陈晓非,2006,三维介质中速度结构和界面的联合成像,地球物理学报,49(4),1062～1067。
Snoke J A,Munsey J W,Teague A G,et al,1984,A program for focal mechanism determination by combined use of polarity andSV-P amplitude ratio data,Earthquake Notes,55(3),15～20.
Snoke J A,1989,Earthquake mechanism,James D E.Encyclopedia of Geophysics,New York:Van Nostrand Reinhold Company,239～245.
Tatham R H,1982,vP/vS and lithology,Geophysics,47,336～344.
Zhao D P,Hasegawa A,Horiuchi S,1992,Tomographic imaging of P and S wave velocity structure beneath Northeastern Japan,JGeophys Res,97(B3),19909～19928.
车自成、刘良、罗金海等,2002,中国及其邻区区域大地构造学,395～413,北京:科学出版社。
刘福田,1984,震源位置和速度结构的联合反演(I)——理论和方法,地球物理学报,27(2),167～175。
刘杰、郑斯华、康英等,2004,利用P波和S波的初动和振幅比计算中小地震的震源机制解,地震,24(1),19～26。
王椿镛、张先康、陈步云等,1997a,大别造山带地壳结构研究,中国科学(D辑),27(3),221～226。
王椿镛、张先康、丁志峰等,1997b,大别造山带上部地壳结构的有限差分层析成像,地球物理学报,40(4),495～502。
徐佩芬、刘福田、王清晨等,2000,大别-苏鲁碰撞造山带的地震层析成像研究:岩石圈三维速度结构,地球物理学报,43(3),377～385。
朱光、徐嘉炜、刘国生等,1998,下扬子地区沿江前陆盆地形成的构造控制,地质论评,44(2),120～129。
周龙泉、刘福田、陈晓非,2006,三维介质中速度结构和界面的联合成像,地球物理学报,49(4),1062～1067。
Snoke J A,Munsey J W,Teague A G,et al,1984,A program for focal mechanism determination by combined use of polarity andSV-P amplitude ratio data,Earthquake Notes,55(3),15～20.
Snoke J A,1989,Earthquake mechanism,James D E.Encyclopedia of Geophysics,New York:Van Nostrand Reinhold Company,239～245.
Tatham R H,1982,vP/vS and lithology,Geophysics,47,336～344.
Zhao D P,Hasegawa A,Horiuchi S,1992,Tomographic imaging of P and S wave velocity structure beneath Northeastern Japan,JGeophys Res,97(B3),19909～19928.
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