发震构造呈复杂空间关系下相互影响发震的机理研究——以汶川地震为例
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摘要
对发震构造呈复杂几何关系(发震构造在平面投影呈非平行关系)下彼此发震影响的机理进行了研究。从发震的"垂震底继"影响关系研究了1933年迭溪地震M7.5和1976年松潘MS7.2地震对后来发生汶川M8地震的龙门山地震构造的孕震能量叠加的加震作用;同时也指出汶川8级地震对周边断裂的减震作用,计算并指出了其影响减震的距离。研究对CPSHA中对发震构造呈复杂几何关系时,如何确定地震带内各潜在的震源空间分布函数fi,mj提供了大震加减震的判断理论依据。还讨论了汶川地震孕震模式的更复杂性,针对某些用巴颜喀拉块体向东南方向移动挤压龙门山孕震构造,进而解释汶川地震的逆冲性所带来的矛盾的观点,对其孕震的复杂性提出了问题所在和初步探讨。
The influence of seismogenic structures with complex geometric relationships,in which the seismogenic structure is not parallel in the planar projection,on the mechanism of earthquakes is studied.Seismogenic structures that influence each other have a damping effect on regional earthquakes after their occurrences.However,the mechanical mechanism research shows that when the fault distribution is of complex geometry,the increasing and decreasing effect of earthquakes differ.Perpendicular intersectional faults are known as perpendicular faults;those equivalent to the bottom line are known as bottom faults.If an earthquake has occurred on the bottom fault,the perpendicular fault will have damping effect,which is known as the occurrence of an earthquake on a bottom fault following the occurrence of an earthquake on a perpendicular fault.If a strong earthquake has occurred on the perpendicular fault,a strong earthquake occurring on the bottom fault is known as the occurrence of a smaller earthquake on a perpendicular fault following the occurrence of an earthquake on a bottom fault.When earthquake occurs on a bottom fault,the relation between magnitude M and damping distance R to the perpendicular fault islg R=0.49 MS-1.97(1) where R is the damping distance in kilometers and MS is magnitude.When an earthquake occurs on a perpendicular fault,which is nearly at a right angle with the bottom fault,energy accumulates in the bottom fault.This result is conducive to damping and is more conducive to the accumulation of energy for earthquakes.When the distance between the top and the end parts of a seismogenic fault on a perpendicular fault is approximately 2~3 times the length L of the seismogenic fault on the perpendicular fault,energy may be superimposed on the bottom fault.The relation between length L and magnitude M on the perpendicular fault islog L=0.48M-1.57(2) Using the relationship of the occurrence of a smaller earthquake on a perpendicular fault following the occurrence of an earthquake on a bottom fault,we investigated the influence of the 1933 Diexi M7.5 earthquake and the 1976 MS7.2 earthquake in Songpan and the effect of energy superposition of the Longmen Mountain seismic structure,which later led to the Wenchuan MS 8.0 earthquake. The seismogenic structure of the Diexi and Songpan earthquakes is approximately orthogonal to that of the Wenchuan earthquake.These earthquakes are more conducive to earthquake occurrences than to shock absorption because of the accumulation of energy. In addition,the complexity of the model of earthquakes occurred in Wenchuan was discussed.Some authors determined that the thrust of the Wenchuan earthquake was caused by the Bayan Har block moving southeastward,which squeezed the Longmen Mountain seismogenic structure.We discussed the complexity of mechanical contradiction for this explanation. In this study,according to China Probabilistic Seismic Hazard Analysis(CPSHA) and the complex geometric relationship of seismogenic structures,we demonstrated the manner in which the seismic zone of the potential seismic source distribution function fi,mj,is identified,and we provided an index of intricate for evaluation.
The influence of seismogenic structures with complex geometric relationships,in which the seismogenic structure is not parallel in the planar projection,on the mechanism of earthquakes is studied.Seismogenic structures that influence each other have a damping effect on regional earthquakes after their occurrences.However,the mechanical mechanism research shows that when the fault distribution is of complex geometry,the increasing and decreasing effect of earthquakes differ.Perpendicular intersectional faults are known as perpendicular faults;those equivalent to the bottom line are known as bottom faults.If an earthquake has occurred on the bottom fault,the perpendicular fault will have damping effect,which is known as the occurrence of an earthquake on a bottom fault following the occurrence of an earthquake on a perpendicular fault.If a strong earthquake has occurred on the perpendicular fault,a strong earthquake occurring on the bottom fault is known as the occurrence of a smaller earthquake on a perpendicular fault following the occurrence of an earthquake on a bottom fault.When earthquake occurs on a bottom fault,the relation between magnitude M and damping distance R to the perpendicular fault islg R=0.49 MS-1.97(1) where R is the damping distance in kilometers and MS is magnitude.When an earthquake occurs on a perpendicular fault,which is nearly at a right angle with the bottom fault,energy accumulates in the bottom fault.This result is conducive to damping and is more conducive to the accumulation of energy for earthquakes.When the distance between the top and the end parts of a seismogenic fault on a perpendicular fault is approximately 2~3 times the length L of the seismogenic fault on the perpendicular fault,energy may be superimposed on the bottom fault.The relation between length L and magnitude M on the perpendicular fault islog L=0.48M-1.57(2) Using the relationship of the occurrence of a smaller earthquake on a perpendicular fault following the occurrence of an earthquake on a bottom fault,we investigated the influence of the 1933 Diexi M7.5 earthquake and the 1976 MS7.2 earthquake in Songpan and the effect of energy superposition of the Longmen Mountain seismic structure,which later led to the Wenchuan MS 8.0 earthquake. The seismogenic structure of the Diexi and Songpan earthquakes is approximately orthogonal to that of the Wenchuan earthquake.These earthquakes are more conducive to earthquake occurrences than to shock absorption because of the accumulation of energy. In addition,the complexity of the model of earthquakes occurred in Wenchuan was discussed.Some authors determined that the thrust of the Wenchuan earthquake was caused by the Bayan Har block moving southeastward,which squeezed the Longmen Mountain seismogenic structure.We discussed the complexity of mechanical contradiction for this explanation. In this study,according to China Probabilistic Seismic Hazard Analysis(CPSHA) and the complex geometric relationship of seismogenic structures,we demonstrated the manner in which the seismic zone of the potential seismic source distribution function fi,mj,is identified,and we provided an index of intricate for evaluation.
引文
[1]卢寿德主编.(GB-17741-2005)工程场地地震安全性评价宣贯教材[M].北京:中国标准出版社,2006.LU Shou-de.(GB-17741-2005)Evaluation of Seismic Safe-ty for Engineering Sites(Teaching material)[M].Beijing:Chi-na Standards Press,2006.
[2]胡聿贤.地震安全性评价教程[M].北京:地震出版社,1999.HU Yu-xian.Seismic Safety evaluation Technology Tutorial[M].Beijing:Seismological Press,1999.
[3]Cornell C A.Engineering Seismic Risk Anysis[J].Bul.Seism.Soc.Amer.,1968,58:1583-1606.
[4]郭增建,秦保燕.大震重复性与减震作用[J].西北地震学报,1984,6(4):89-96.GUO Zeng-jian,QIN Bao-yan.Repetition of Strong Earth-quake and Reduction of Seismic risk[J].Northwestern Seis-mological Journal,1984,6(4):89-96.
[5]GUO An-ning.Discussion on Problem of Earthquake Reduc-tion[J].Northwestern Seismological Journal,1989,11(2):96-99.
[6]郭安宁,陈家超.中国大震问题[M].北京:地震出版社,2002.GUO An-ning,CHENG Jia-chao.Strong Earthquake Problemof China[M].Beijing:Seismological Press,2002.
[7]郭安宁.考虑发震断层相互作用的地震危险性分析讨论[J].西北地震学报,1989,11(增刊):22-28.GUO An-ning.Discussion of Seismic Hazard Analysis Consid-ering Earthquake Fault Interaction[J].Northwestern Seismo-logical Journal,1989,11(Supp.):22-28.
[8]鄢家全,贾素娟.华北地区大地震的减震作用[A]//地震区划文集[G].北京:地震出版社,1993:112-116.YAN Jiao-quan,JIA Su-juan.The damping effect of thestrong earthquake in North China[A]//Seismic zoning anthol-ogy[G].Beijing:Seismological Press,1993:112-116.
[9]雷建成,时振梁,鄢家全.确定潜在震源区地震年平均发生率的方法研究[J].地震学报,1991,13(4):496-504.LEI Jian-chang,SHI Zhen-liang,YAN Jiao-quan.Method ofDetermining the Average Annual Incidence of Earthquake inPotential Seismic zone[J].Earthquake Science,13(4):496-504.
[10]付碧宏,时丕龙,王萍,等.2008年汶川地震断层北川段的几何学与运动学特征及地震地质灾害效应[J],地球物理学报,2009,52(2):485-495.FU Bi-hong,FU Bi-Hong,SHI Pi-Long,et al.Geometryand Kinematics of the 2008 Wenchuan Earthquake SurfaceRuptures Around the Qushan Town of Beichuan County,Si-chuan:Implications for Mitigation of Seismic and GeologicDisasters[J].Chinese Journal of Geophysics,2009,52(2):485-495.
[11]闻学泽,张培震,杜方,等.2008年汶川8.0级地震发生的历史与现今地震活动背景[J].地球物理学报,2009,52(2):444-454.WEN Xue-ze,ZHANG Pei-zhen,DU Fang,et al.The Back-ground of Historical and Modern Seismic Activities of the Oc-currence of the 2008 MS8.0Wenchuan,Sichuan,Earthquake[J].Chinese Journal of Geophysics,2009,52(2):444-454.
[12]郭安宁,郭增建.5.12汶川地震预报回顾[M].西安:西安地图出版社,2009.GUO An-ning,GUO Zeng-jian.The 5.12Wenchuan Earth-quake Prediction Review[M].Xi'an:Xi'an Map PublishingHouse,2009.
[13]郭安宁.郭增建、焦姣,等.青海玉树7.1级大震的预测讨论[J].西北地震学报,2012,34(1),39-43.GUO An-ning,GUO Zeng-jian,JIAO Jiao,et al.Discussionon Prediction of Qinghai Yushu MS7.1 Earthquake[J].Northwestern Seisological Journal,2012,34(1),39-43.
[14]刘白云,袁道阳,陈继锋,等.玉树MS7.1地震时空破裂过程及与地表破裂带的对应关系[J].西北地震学报,2012,34(1),23-29.LIU Bai-yun,YUAN Dao-yang,CHEN Ji-fen,et al.The Cor-responding Relationship between Temporal-apatial Processand Earthquake Surface Ruptures Zone of Yushu MS7.1Earthquake[J].Northwestern Seisological Journal,2012,34(1),23-29.
[15]郭安宁,郭增建.从震源模式讨论2008年汶川8级地震的回顾性预测[J].地震地质,2010,32(1):115-126.GUO An-ning,GUO Zeng-jian.A Discussion on the Retro-spective Prediction of the MS8.0 Wenchuan Earthquake in2008by Means of Earthquake Source models[J].Seismologyand Geology,2010,(1):115-126.
[16]李延兴,等.汶川MS8.0地震孕育发生的机制与动力学问题[J].地球物理学报,2009,52(2):519-531.LI Yan-xing,et al.The Mechanism and Dynamics of theGeneration and Occurrence for Wenchuan MS8.0Earthquake[J].Chinese Journal of Geophysics,2009,52(2):519-531.
[17]郭增建,秦保燕.地震成因与地震预报[M].北京:地震出版社,1991.GUO Zeng-jian,QIN Bao-yan.The Cause of Earthquakes andEarthquake Prediction[M].Beijing:Seismological Press,1991.
[18]贾鹏,张希,张晓亮,等.汶川地震前后川滇及其邻区GPS水平运动演化特征[J].西北地震学报,2012,34(3),264-267,273.JIA Peng,ZHANG Xi,ZHANG Xiao-liang,et al.EvolutionFeatures of Crustal Horizontal Movement from GPS Observa-tion in Sichuan-Yunnan Region and Its Adjacent Area beforeand after the Wenchuan Earthquake[J].Northwestern Seiso-logical Journal,2012,34(3),264-267,273.
[19]和平,李志雄,陆远忠,等.断层面的有限单元模拟方法综述[J].,西北地震学报,2011,33(2),186-194.HE Ping,LI Zhi-xiong,LU Yuan-zhong,et al.Overview ofResearches on Fault Simulation by Finite Element Method[J].Northwestern Seisological Journal,2011,33(2),186-194.
[2]胡聿贤.地震安全性评价教程[M].北京:地震出版社,1999.HU Yu-xian.Seismic Safety evaluation Technology Tutorial[M].Beijing:Seismological Press,1999.
[3]Cornell C A.Engineering Seismic Risk Anysis[J].Bul.Seism.Soc.Amer.,1968,58:1583-1606.
[4]郭增建,秦保燕.大震重复性与减震作用[J].西北地震学报,1984,6(4):89-96.GUO Zeng-jian,QIN Bao-yan.Repetition of Strong Earth-quake and Reduction of Seismic risk[J].Northwestern Seis-mological Journal,1984,6(4):89-96.
[5]GUO An-ning.Discussion on Problem of Earthquake Reduc-tion[J].Northwestern Seismological Journal,1989,11(2):96-99.
[6]郭安宁,陈家超.中国大震问题[M].北京:地震出版社,2002.GUO An-ning,CHENG Jia-chao.Strong Earthquake Problemof China[M].Beijing:Seismological Press,2002.
[7]郭安宁.考虑发震断层相互作用的地震危险性分析讨论[J].西北地震学报,1989,11(增刊):22-28.GUO An-ning.Discussion of Seismic Hazard Analysis Consid-ering Earthquake Fault Interaction[J].Northwestern Seismo-logical Journal,1989,11(Supp.):22-28.
[8]鄢家全,贾素娟.华北地区大地震的减震作用[A]//地震区划文集[G].北京:地震出版社,1993:112-116.YAN Jiao-quan,JIA Su-juan.The damping effect of thestrong earthquake in North China[A]//Seismic zoning anthol-ogy[G].Beijing:Seismological Press,1993:112-116.
[9]雷建成,时振梁,鄢家全.确定潜在震源区地震年平均发生率的方法研究[J].地震学报,1991,13(4):496-504.LEI Jian-chang,SHI Zhen-liang,YAN Jiao-quan.Method ofDetermining the Average Annual Incidence of Earthquake inPotential Seismic zone[J].Earthquake Science,13(4):496-504.
[10]付碧宏,时丕龙,王萍,等.2008年汶川地震断层北川段的几何学与运动学特征及地震地质灾害效应[J],地球物理学报,2009,52(2):485-495.FU Bi-hong,FU Bi-Hong,SHI Pi-Long,et al.Geometryand Kinematics of the 2008 Wenchuan Earthquake SurfaceRuptures Around the Qushan Town of Beichuan County,Si-chuan:Implications for Mitigation of Seismic and GeologicDisasters[J].Chinese Journal of Geophysics,2009,52(2):485-495.
[11]闻学泽,张培震,杜方,等.2008年汶川8.0级地震发生的历史与现今地震活动背景[J].地球物理学报,2009,52(2):444-454.WEN Xue-ze,ZHANG Pei-zhen,DU Fang,et al.The Back-ground of Historical and Modern Seismic Activities of the Oc-currence of the 2008 MS8.0Wenchuan,Sichuan,Earthquake[J].Chinese Journal of Geophysics,2009,52(2):444-454.
[12]郭安宁,郭增建.5.12汶川地震预报回顾[M].西安:西安地图出版社,2009.GUO An-ning,GUO Zeng-jian.The 5.12Wenchuan Earth-quake Prediction Review[M].Xi'an:Xi'an Map PublishingHouse,2009.
[13]郭安宁.郭增建、焦姣,等.青海玉树7.1级大震的预测讨论[J].西北地震学报,2012,34(1),39-43.GUO An-ning,GUO Zeng-jian,JIAO Jiao,et al.Discussionon Prediction of Qinghai Yushu MS7.1 Earthquake[J].Northwestern Seisological Journal,2012,34(1),39-43.
[14]刘白云,袁道阳,陈继锋,等.玉树MS7.1地震时空破裂过程及与地表破裂带的对应关系[J].西北地震学报,2012,34(1),23-29.LIU Bai-yun,YUAN Dao-yang,CHEN Ji-fen,et al.The Cor-responding Relationship between Temporal-apatial Processand Earthquake Surface Ruptures Zone of Yushu MS7.1Earthquake[J].Northwestern Seisological Journal,2012,34(1),23-29.
[15]郭安宁,郭增建.从震源模式讨论2008年汶川8级地震的回顾性预测[J].地震地质,2010,32(1):115-126.GUO An-ning,GUO Zeng-jian.A Discussion on the Retro-spective Prediction of the MS8.0 Wenchuan Earthquake in2008by Means of Earthquake Source models[J].Seismologyand Geology,2010,(1):115-126.
[16]李延兴,等.汶川MS8.0地震孕育发生的机制与动力学问题[J].地球物理学报,2009,52(2):519-531.LI Yan-xing,et al.The Mechanism and Dynamics of theGeneration and Occurrence for Wenchuan MS8.0Earthquake[J].Chinese Journal of Geophysics,2009,52(2):519-531.
[17]郭增建,秦保燕.地震成因与地震预报[M].北京:地震出版社,1991.GUO Zeng-jian,QIN Bao-yan.The Cause of Earthquakes andEarthquake Prediction[M].Beijing:Seismological Press,1991.
[18]贾鹏,张希,张晓亮,等.汶川地震前后川滇及其邻区GPS水平运动演化特征[J].西北地震学报,2012,34(3),264-267,273.JIA Peng,ZHANG Xi,ZHANG Xiao-liang,et al.EvolutionFeatures of Crustal Horizontal Movement from GPS Observa-tion in Sichuan-Yunnan Region and Its Adjacent Area beforeand after the Wenchuan Earthquake[J].Northwestern Seiso-logical Journal,2012,34(3),264-267,273.
[19]和平,李志雄,陆远忠,等.断层面的有限单元模拟方法综述[J].,西北地震学报,2011,33(2),186-194.HE Ping,LI Zhi-xiong,LU Yuan-zhong,et al.Overview ofResearches on Fault Simulation by Finite Element Method[J].Northwestern Seisological Journal,2011,33(2),186-194.
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