汶川8.0级地震前后龙门山断裂活动特征浅析
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摘要
利用跨龙门山断裂的流动短水准观测资料分析了汶川地震前后各测点的变化特征。分析认为:1)汶川地震前(2006年)跨断层短水准观测到了龙门山断裂的活动,且在震前均出现不同程度的加速活动特征;2)震前龙门山断裂中南段为逆断层活动,地表变形呈反"S"型;3)跨断层位移测量反映了汶川地震区域地表应力集中、释放的时空演化过程,且机理解释与震源机制解基本一致。
In this paper by utilizing the mobile short-line leveling data across the Longmenshan fault the variation characteristics at each observation site before and after the Wenchuan earthquake are analyzed.By analyzing the motion type and stress pattern of the Longmenshan fault we investigated the seismogenic process and mechanism of the earthquake.The preliminary results are as follows.a)Before the Wenchuan earthquake the cross-fault short-line leveling in 2006 showed the activity at all of the stations of Longmenshan fault with a characteristic of accelerative movement to different degrees.b)Before the earthquake the short-line leveling indicated that the middle-south segment of Longmenshan fault showed reverse faulting movement,and the fault deformation was of inversive "S" type.c)Before and after the Wenchuan earthquake the cross-fault displacement measurements reflected the spatial-temporal evolution of the accumulation and release of regional surface stress,the interpretation of their mechanism is basically consistent with the focal mechanism solution.
In this paper by utilizing the mobile short-line leveling data across the Longmenshan fault the variation characteristics at each observation site before and after the Wenchuan earthquake are analyzed.By analyzing the motion type and stress pattern of the Longmenshan fault we investigated the seismogenic process and mechanism of the earthquake.The preliminary results are as follows.a)Before the Wenchuan earthquake the cross-fault short-line leveling in 2006 showed the activity at all of the stations of Longmenshan fault with a characteristic of accelerative movement to different degrees.b)Before the earthquake the short-line leveling indicated that the middle-south segment of Longmenshan fault showed reverse faulting movement,and the fault deformation was of inversive "S" type.c)Before and after the Wenchuan earthquake the cross-fault displacement measurements reflected the spatial-temporal evolution of the accumulation and release of regional surface stress,the interpretation of their mechanism is basically consistent with the focal mechanism solution.
引文
[1]中国地震局监测预报司预报处编.中国地震目录,2005.
[2]苏琴,段明.耿达短水准场地异常核实报告.四川省地震局,2007-09.
[3]陈运泰,等.2008年5月12日汶川特大地震震源特性分析报告.2008.
1唐荣昌,韩渭宾.四川活动断裂与地震[M].北京:地震出版社,1993.1Tang Rongchang and Han Weibin.Active faults and earth-quakes in Sichuan[M].Beijing:Seismological Press,1993.(in Chinese)
2吕江宁,等.川滇地区现代地壳运动速度场和活动块体模型研究[J].地震地质,2003,25(4):543-554.2Lu Jiangning,et al.A model study of modern crust move-ment velocity field and active blocks in the Chuan-Dian re-gion[J].Seismology and Geology,2003,25(4):543-554.(in Chinese)
3唐文清,等.龙门山断裂构造带GPS研究[J].大地测量与地球动力学,2004,24(3):57-59.3Tang Wenqing,et al.GPS study on Longmenshan fault zone[J].Journal of Geodesy and Geodynamics,2004,24(3):57-59.(in Chinese)
4安其美,等.龙门山断裂带的性质与活动性研究[J].大地测量与地球动力学,2004,24(2):115-119.4An Qimei,et al.Research of property and activity of Long-menshan fault zone[J].Journal of Geodesy and Geodynam-ics,2004,24(2):115-119.(in Chinese)
[2]苏琴,段明.耿达短水准场地异常核实报告.四川省地震局,2007-09.
[3]陈运泰,等.2008年5月12日汶川特大地震震源特性分析报告.2008.
1唐荣昌,韩渭宾.四川活动断裂与地震[M].北京:地震出版社,1993.1Tang Rongchang and Han Weibin.Active faults and earth-quakes in Sichuan[M].Beijing:Seismological Press,1993.(in Chinese)
2吕江宁,等.川滇地区现代地壳运动速度场和活动块体模型研究[J].地震地质,2003,25(4):543-554.2Lu Jiangning,et al.A model study of modern crust move-ment velocity field and active blocks in the Chuan-Dian re-gion[J].Seismology and Geology,2003,25(4):543-554.(in Chinese)
3唐文清,等.龙门山断裂构造带GPS研究[J].大地测量与地球动力学,2004,24(3):57-59.3Tang Wenqing,et al.GPS study on Longmenshan fault zone[J].Journal of Geodesy and Geodynamics,2004,24(3):57-59.(in Chinese)
4安其美,等.龙门山断裂带的性质与活动性研究[J].大地测量与地球动力学,2004,24(2):115-119.4An Qimei,et al.Research of property and activity of Long-menshan fault zone[J].Journal of Geodesy and Geodynam-ics,2004,24(2):115-119.(in Chinese)
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