临潭-宕昌断裂及附近地区静态库仑应力变化及地震活动性研究
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摘要
基于Okada的弹性半空间模型,分别计算岷县MS6.6、MS5.2地震和岷县-卓尼MS5.0地震对后续地震的静态库仑应力变化,分析应力扰动对后续地震的影响。结果显示:1)研究区内3次中强地震的共同作用促进了后续地震的发生,后续地震绝大部分位于应力增加区内;2)临潭-宕昌区域背景地震活动性较强,尤其是宕昌及周边地区,地震活动呈条带状展布,与临潭-宕昌断裂走向垂直,研究区整体地震活动性变化以宕昌地区为中心向外呈辐射状减弱;3)岷县段、西段和中段处于应力累积阶段,未来发生强震的可能性较小,宕昌段未来一段时间内地震活动性高于区域背景地震活动性,值得高度关注。
Based on Okada's elastic half-space model,the changes of Coulomb stress after the main shock are calculated and the influences of stress disturbance on the subsequent earthquakes are analyzed.The results show that:(1)Three earthquakes in the study area triggered the subsequent aftershocks which are located in areas withΔCFS>0.(2)The seismicity of regional background of LintanTanchang is stronger than that of other areas,especially Tanchang and the adjacent areas,and the distribution of earthquakes is perpendicular to the strike of Lintan-Tanchang fault.The value of seismicity in the study area is reduced from central Tanchang to both edges gradually.(3)The seismicity in Tanchang would be higher than the seismicity of local background in the future,which needs our close attention.The seismicity of other regions in this study area are under that of the background,so the possibility of the occurrence of strong earthquakes would be smaller in the future.
Based on Okada's elastic half-space model,the changes of Coulomb stress after the main shock are calculated and the influences of stress disturbance on the subsequent earthquakes are analyzed.The results show that:(1)Three earthquakes in the study area triggered the subsequent aftershocks which are located in areas withΔCFS>0.(2)The seismicity of regional background of LintanTanchang is stronger than that of other areas,especially Tanchang and the adjacent areas,and the distribution of earthquakes is perpendicular to the strike of Lintan-Tanchang fault.The value of seismicity in the study area is reduced from central Tanchang to both edges gradually.(3)The seismicity in Tanchang would be higher than the seismicity of local background in the future,which needs our close attention.The seismicity of other regions in this study area are under that of the background,so the possibility of the occurrence of strong earthquakes would be smaller in the future.
引文
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[2]解朝娣,朱元清,Lei X L,等.MS8.0汶川地震产生的应力变化空间分布及其对地震活动性的影响[J].中国科学:地球科学,2010,40(6):688-698(Xie Chaodi,Zhu Yuanqing,Lei X L,et a1.Pattem of Stress Change and Its Effect on Seismicity Rate Caused by 8.0 Wenchuan Earthquake[J].Sci China Earth Sci,2010,40(6):688-698)
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[9]Stein R S,King G C P,Lin J.Change in Failure Stress on the Southern San Andreas Fault System Caused by the 1992Magnitude=7.4Landers Earthquake[J].Science,1992,258(5 086):1 328-1 332
[10]King G C P,Stein R S,Lin J.Static Stress Changes and the Triggering of Earthquakes[J].Bulletin of the Seismological Society of America,1994,84(3):935-953
[11]Wells D L,Coppersmith K J.New Empirical Relationships among Magnitude,Rupture Length,Rupture Width,Rupture Area,and Surface Displacement[J].Bulletin of the Seismological Society of America,1994,84(4):974-1 002
[12]刘方斌,曲均浩,田兆阳,等.基于黏弹性模型的苍山地震库仑应力变化研究[J].地震工程学报,2017(1):133-140(Liu Fangbin,Qu Junhao,Tian Zhaoyang,et al.Coulomb Stress Changes Induced by Cangshan MS5.2 Earthquake Based on Visco-Elastic Model[J].China Earthquake Engineering Journal,2017(1):133-140)
[13]Hainzl S,Enescu B,Cocco M,et al.Aftershock Modeling Based on Uncertain Stress Calculations[J].Journal of Geophysical Research:Solid Earth,2009,114(B5)
[14]Toda S,Lin J,Meghraoui M,et al.12 May 2008 M=7.9Wenchuan,China,Earthquake Calculated to Increase Failure Stress and Seismicity Rate on Three Major Fault Systems[J].Geophysical Research Letters,2008,35(17)
[15]袁道阳,雷中生,何文贵,等.公元前186年甘肃武都地震考证与发震构造探讨[J].地震学报,2007,29(6):654-663(Yuan Daoyang,Lei Zhongsheng,He Wengui,et al.Textual Research of Wudu Earthquake in 186B.C.in Gansu Province,China and Discussion on Its Causative Structure[J].Acta Seismologica Sinica,2007,29(6):654-663)
[16]郑文俊,闵伟,何文贵,等.甘肃岷县漳县6.6级地震震害分布特征及发震构造分析[J].地震地质,2013,35(3):604-615(Zheng Wenjun,Min Wei,He Wengui,et al.The Related Disaster Characteristics and Causative Tectonic of the Minxian-Zhanxian MS6.6 Earthquake on July 22,2013,Gansu[J].Seismology and Geology,2013,35(3):604-615)
[2]解朝娣,朱元清,Lei X L,等.MS8.0汶川地震产生的应力变化空间分布及其对地震活动性的影响[J].中国科学:地球科学,2010,40(6):688-698(Xie Chaodi,Zhu Yuanqing,Lei X L,et a1.Pattem of Stress Change and Its Effect on Seismicity Rate Caused by 8.0 Wenchuan Earthquake[J].Sci China Earth Sci,2010,40(6):688-698)
[3]何文贵,郑文俊,王爱国,等.临潭宕昌断裂新活动特征与岷县漳县MS6.6地震关系研究[J].地震工程学报,2013,35(4):751-760(He Wengui,Zheng Wenjun,Wang Aiguo,et al.New Activities of Lintan-Tanchang Fault and Its Relations to Minxian-Zhangxian MS6.6Earthquake[J].China Earthquake Engineering Journal,2013,35(4):751-760)
[4]郑文俊,刘小凤,赵广,等.2003年11月13日甘肃岷县MS5.2地震基本特征[J].西北地震学报,2005,27(1):61-65(Zheng Wenjun,Liu Xiaofeng,Zhao Guang,et al.Principal Features of Minxian MS5.2 Earthquake in Gansu Province,on Nov.13,2003[J].Northwestern Seismological Journal,2005,27(1):61-65)
[5]何文贵,周志宇,马尔曼,等.岷县-卓尼5.0级地震的基本特征和地质背景研究[J].地震研究,2006,29(4):373-378(He Wengui,Zhou Zhiyu,Ma Erman,et al.Basic Features and Geological Background of the Minxian-Zhuoni M5.0Earthquake on Sep.7,2004[J].Journal of Seismological Research,2006,29(4):373-378)
[6]Okada Y.Internal Deformation Due to Shear and Tensile Faults in a Half Space[J].Bull Seism Soc Amer,1992,82(2):1 018-1 040
[7]Dieterich J.A Constitutive Law for Rate of Earthquake Production and Its Application to Earthquake Clustering[J].Journal of Geophysical Research:Solid Earth,1994,99(B2):2 601-2 618
[8]万永革,吴忠良,周公威,等.几次复杂地震中不同破裂事件之间的“应力触发”问题[J].地震学报,2000,22(6):568-576(Wan Yongge,Wu Zhongliang,Zhou Gongwei,et al."Stress Triggering"between Different Rupture Events in Several Earthquakes[J].Acta Seismologica Sinica,2000,22(6):568-576)
[9]Stein R S,King G C P,Lin J.Change in Failure Stress on the Southern San Andreas Fault System Caused by the 1992Magnitude=7.4Landers Earthquake[J].Science,1992,258(5 086):1 328-1 332
[10]King G C P,Stein R S,Lin J.Static Stress Changes and the Triggering of Earthquakes[J].Bulletin of the Seismological Society of America,1994,84(3):935-953
[11]Wells D L,Coppersmith K J.New Empirical Relationships among Magnitude,Rupture Length,Rupture Width,Rupture Area,and Surface Displacement[J].Bulletin of the Seismological Society of America,1994,84(4):974-1 002
[12]刘方斌,曲均浩,田兆阳,等.基于黏弹性模型的苍山地震库仑应力变化研究[J].地震工程学报,2017(1):133-140(Liu Fangbin,Qu Junhao,Tian Zhaoyang,et al.Coulomb Stress Changes Induced by Cangshan MS5.2 Earthquake Based on Visco-Elastic Model[J].China Earthquake Engineering Journal,2017(1):133-140)
[13]Hainzl S,Enescu B,Cocco M,et al.Aftershock Modeling Based on Uncertain Stress Calculations[J].Journal of Geophysical Research:Solid Earth,2009,114(B5)
[14]Toda S,Lin J,Meghraoui M,et al.12 May 2008 M=7.9Wenchuan,China,Earthquake Calculated to Increase Failure Stress and Seismicity Rate on Three Major Fault Systems[J].Geophysical Research Letters,2008,35(17)
[15]袁道阳,雷中生,何文贵,等.公元前186年甘肃武都地震考证与发震构造探讨[J].地震学报,2007,29(6):654-663(Yuan Daoyang,Lei Zhongsheng,He Wengui,et al.Textual Research of Wudu Earthquake in 186B.C.in Gansu Province,China and Discussion on Its Causative Structure[J].Acta Seismologica Sinica,2007,29(6):654-663)
[16]郑文俊,闵伟,何文贵,等.甘肃岷县漳县6.6级地震震害分布特征及发震构造分析[J].地震地质,2013,35(3):604-615(Zheng Wenjun,Min Wei,He Wengui,et al.The Related Disaster Characteristics and Causative Tectonic of the Minxian-Zhanxian MS6.6 Earthquake on July 22,2013,Gansu[J].Seismology and Geology,2013,35(3):604-615)