龙门山和鲜水河断裂带对区域构造加载作用的动态响应
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摘要
为了研究汶川地震和鲜水河断裂带上的地震之间是否有触发作用及区域构造加载作用在这些地震发生过程中对应力场的影响.我们以汶川地震和鲜水河断裂带所在区域上的共7次地震为研究对象,区域构造加载作用由GPS速度边界近似,用分裂节点技术模拟上地壳地震的发生,并采用三维黏弹性有限元方法,模拟库仑应力的演化.研究结果表明:鲜水河断裂带上的地震震前积累的库仑应力的17%~38%来自区域构造加载的持续作用,其他的地震形变引起的库仑应力的积累约占49%~67%,故地震触发作用明显(除1948年理塘地震和1973年炉霍地震外);而汶川地震震前1893—1981年发生的地震释放了该区部分库仑应力,不可能对汶川地震有触发作用.汶川地震的库仑应力积累可能主要来自区域构造加载作用,地震发生以后几乎释放了所在区域的所有库仑应力,形成新的格局.
In order to study the trigger interaction between the Wenchuan earthquake and the earthquakes on the Xianshuihe fault zone as well as the stress changing with the effect of regional tectonic loading,we have studied the seven major earthquakes in the Xianshuihe and Longmenshan fault zones.The regional tectonic loading is approximated by velocity boundaries from GPS data.The split-node technique was used to simulate the earthquakes in upper crust. With the threedimensional viscoelastic finite element code we simulated the evolution of Coulomb stress.The results show that the trigger interaction between the Wenchuan earthquake and the earthquakes on Xianshuihe fault zone is different.The trigger interaction is obvious on the Xianshuihe fault zone(except the Litang earthquake in 1948 and the Luhuo earthquake in 1973),as 17 to 38percentages′Coulomb stress increasing was caused by regional tectonic loading,other49 to 67percentages of stress was contributed by earthquake deformation.However,part of theCoulomb stress was released by the earthquakes that happened from 1893 to 1981.So it is impossible that the Wenchuan earthquake was triggered by the earthquakes in the past.The Coulomb stress in the Wenchuan earthquake was mainly increased from regional tectonic loading.With occurrence of this earthquake,the certain region released almost all the Coulomb stress and became into a new condition.
In order to study the trigger interaction between the Wenchuan earthquake and the earthquakes on the Xianshuihe fault zone as well as the stress changing with the effect of regional tectonic loading,we have studied the seven major earthquakes in the Xianshuihe and Longmenshan fault zones.The regional tectonic loading is approximated by velocity boundaries from GPS data.The split-node technique was used to simulate the earthquakes in upper crust. With the threedimensional viscoelastic finite element code we simulated the evolution of Coulomb stress.The results show that the trigger interaction between the Wenchuan earthquake and the earthquakes on Xianshuihe fault zone is different.The trigger interaction is obvious on the Xianshuihe fault zone(except the Litang earthquake in 1948 and the Luhuo earthquake in 1973),as 17 to 38percentages′Coulomb stress increasing was caused by regional tectonic loading,other49 to 67percentages of stress was contributed by earthquake deformation.However,part of theCoulomb stress was released by the earthquakes that happened from 1893 to 1981.So it is impossible that the Wenchuan earthquake was triggered by the earthquakes in the past.The Coulomb stress in the Wenchuan earthquake was mainly increased from regional tectonic loading.With occurrence of this earthquake,the certain region released almost all the Coulomb stress and became into a new condition.
引文
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He J K,Peltzer G.2010.Poroelastic triggering in the 9-22,January2008Nima-Gaize(Tibet)earthquake sequence.Geology,38(10):907-910.
He J K,Xia W H,Lu S J,et al.2011.Three-dimensional finite element modeling of stress evolution around the Xiaojiang fault system in the southeastern Tibetan plateau during the past-500years.Tectonophysics,507(1-4):70-85.
Hu C B,Cai Y N,Wang Z M.2012.Effects of large historical earthquakes,viscous relaxation,and tectonic loading on the2008 Wenchuan earthquake.J.Geophys.Res.,117:B06410,doi:10.1029/2011JB009046.
Jaeger J C,Cook N G W.1979.Fundamentals of Rock Mechanics,3rd ed.London:Chapman and Hall.
King G C P,Stein R S,Lin J.1994.Static stress changes and the triggering of earthquakes.Bull.Seismol.Soc.Am.,84(3):935-953.
Li Q,Liu M,Zhang H.2009.A 3-D viscoelastoplastic model for simulating long-term slip on non-planar faults.Geophys.J.Int.,176:293-306.
Luo G,Liu M.2010.Stress evolution and fault interactions before and after the 2008 Great Wenchuan earthquake.Tectonophysics,491(1-4):127-140.
Melosh H J,Raefsky A.1981.A simple and efficient method for introducing faults into finite element computations.Bull.Seismol.Soc.Am.,71(5):1391-1400.
Papadimitriou E,Wen X Z,Karakostas V,et al.2004.Earthquake Triggering along the Xianshuihe Fault Zone of Western Sichuan,China.Pure and Applied Geophysics,161(8):1683-1707.
Parsons T,Chen J,Kirby E.2008.Stress changes from the 2008Wenchuan earthquake and increased hazard in the Sichuan basin.Nature,454(7203):509-510.
Shan B,Xiong X,Zheng Y,et al.2009.Stress changes on major faults caused by MW7.9 Wenchuan earthquake,May 12,2008.Sci.China Ser.D:Earth Sci.,52(5):593-601.
Shan B,Xiong X,Wang R J,et al.2013.Coulomb stress evolution along Xianshuihe-Xiaojiang Fault System since 1713 and its interaction with Wenchuan earthquake,May 12,2008.Earth Planet.Sci.Lett.,377-378:199-210.
Shen Z K,LüJ N,Wang M,et al.2005.Contemporary crustal deformation around the southeast borderland of the Tibetan plateau.J.Geophys.Res.,110(B11),doi:10.1029/2004JB003421.
Stein R S.1999.The role of stress transfer in earthquake occurrence.Nature,402(6762):605-609.
Teng J W,Bai D H,Yang H,et al.2008.Deep processes and dynamic responses associated with the Wenchuan MS8.0earthquake of 2008.Chinese J.Geophys.(in Chinese),51(5):1385-1402.
Toda S,Lin J,Meghraoui M,et al.2008.12 May 2008 M=7.9Wenchuan,China,earthquake calculated to increase failure stress and seismicity rate on three major fault systems.Geophys.Res.Lett.,35(17):L17305,doi:10.1029/2008GL034903.
Wang H,Liu J,Shi Y L,et al.2008.Dynamic simulation of interactions between major earthquakes on the Xianshuihe fault zone.Sci.China Ser.D:Earth Sci.,51(10):1388-1400.
Wang W M,Zhao L F,Li J,et al.2008.Rupture process of the MS8.0Wenchuan earthquake of Sichuan,China.ChineseJ.Geophys.(in Chinese),51(5):1403-1410.
Xu J,Shao Z G,Ma H S,et al.2013.Evolution of Coulomb stress and stress interaction among strong earthquakes along the Xianshuihe fault zone.Chinese J.Geophys.(in Chinese),56(4):1146-1158,doi:10.6038/cjg20130410.
Yue Z Q.2013.Cause and mechanism of highly compressed and dense methane gas mass for Wenchuan earthquake and associated rock-avalanches and surface co-seismic ruptures.Earth Science Frontiers(in Chinese),20(6):15-20.
Zhang P Z.2013.Beware of slowly slipping faults.Nature Geoscience,6:323-324.
滕吉文,白登海,杨辉等.2008.2008汶川MS8.0地震发生的深层过程和动力学响应.地球物理学报,51(5):1385-1402.
王辉,刘杰,石耀霖等.2008.鲜水河断裂带强震相互作用的动力学模拟研究.中国科学D辑:地球科学,38(7):808-818.
王卫民,赵连锋,李娟等.2008.四川汶川8.0级地震震源过程.地球物理学报,51(5):1403-1410.
徐晶,邵志刚,马宏生等.2013.鲜水河断裂带库仑应力演化与强震间关系.地球物理学报,56(4):1146-1158,doi:10.6038/cjg20130410.
岳中琦.2013.汶川地震与山崩地裂的极高压甲烷天然气成因和机理.地学前缘,20(6):15-20.
Harris R A.1998.Introduction to special section:Stress triggers,stress shadows,and implications for seismic hazard.J.Geophys.Res.,103(B10):24347-24358.
He J K,Peltzer G.2010.Poroelastic triggering in the 9-22,January2008Nima-Gaize(Tibet)earthquake sequence.Geology,38(10):907-910.
He J K,Xia W H,Lu S J,et al.2011.Three-dimensional finite element modeling of stress evolution around the Xiaojiang fault system in the southeastern Tibetan plateau during the past-500years.Tectonophysics,507(1-4):70-85.
Hu C B,Cai Y N,Wang Z M.2012.Effects of large historical earthquakes,viscous relaxation,and tectonic loading on the2008 Wenchuan earthquake.J.Geophys.Res.,117:B06410,doi:10.1029/2011JB009046.
Jaeger J C,Cook N G W.1979.Fundamentals of Rock Mechanics,3rd ed.London:Chapman and Hall.
King G C P,Stein R S,Lin J.1994.Static stress changes and the triggering of earthquakes.Bull.Seismol.Soc.Am.,84(3):935-953.
Li Q,Liu M,Zhang H.2009.A 3-D viscoelastoplastic model for simulating long-term slip on non-planar faults.Geophys.J.Int.,176:293-306.
Luo G,Liu M.2010.Stress evolution and fault interactions before and after the 2008 Great Wenchuan earthquake.Tectonophysics,491(1-4):127-140.
Melosh H J,Raefsky A.1981.A simple and efficient method for introducing faults into finite element computations.Bull.Seismol.Soc.Am.,71(5):1391-1400.
Papadimitriou E,Wen X Z,Karakostas V,et al.2004.Earthquake Triggering along the Xianshuihe Fault Zone of Western Sichuan,China.Pure and Applied Geophysics,161(8):1683-1707.
Parsons T,Chen J,Kirby E.2008.Stress changes from the 2008Wenchuan earthquake and increased hazard in the Sichuan basin.Nature,454(7203):509-510.
Shan B,Xiong X,Zheng Y,et al.2009.Stress changes on major faults caused by MW7.9 Wenchuan earthquake,May 12,2008.Sci.China Ser.D:Earth Sci.,52(5):593-601.
Shan B,Xiong X,Wang R J,et al.2013.Coulomb stress evolution along Xianshuihe-Xiaojiang Fault System since 1713 and its interaction with Wenchuan earthquake,May 12,2008.Earth Planet.Sci.Lett.,377-378:199-210.
Shen Z K,LüJ N,Wang M,et al.2005.Contemporary crustal deformation around the southeast borderland of the Tibetan plateau.J.Geophys.Res.,110(B11),doi:10.1029/2004JB003421.
Stein R S.1999.The role of stress transfer in earthquake occurrence.Nature,402(6762):605-609.
Teng J W,Bai D H,Yang H,et al.2008.Deep processes and dynamic responses associated with the Wenchuan MS8.0earthquake of 2008.Chinese J.Geophys.(in Chinese),51(5):1385-1402.
Toda S,Lin J,Meghraoui M,et al.2008.12 May 2008 M=7.9Wenchuan,China,earthquake calculated to increase failure stress and seismicity rate on three major fault systems.Geophys.Res.Lett.,35(17):L17305,doi:10.1029/2008GL034903.
Wang H,Liu J,Shi Y L,et al.2008.Dynamic simulation of interactions between major earthquakes on the Xianshuihe fault zone.Sci.China Ser.D:Earth Sci.,51(10):1388-1400.
Wang W M,Zhao L F,Li J,et al.2008.Rupture process of the MS8.0Wenchuan earthquake of Sichuan,China.ChineseJ.Geophys.(in Chinese),51(5):1403-1410.
Xu J,Shao Z G,Ma H S,et al.2013.Evolution of Coulomb stress and stress interaction among strong earthquakes along the Xianshuihe fault zone.Chinese J.Geophys.(in Chinese),56(4):1146-1158,doi:10.6038/cjg20130410.
Yue Z Q.2013.Cause and mechanism of highly compressed and dense methane gas mass for Wenchuan earthquake and associated rock-avalanches and surface co-seismic ruptures.Earth Science Frontiers(in Chinese),20(6):15-20.
Zhang P Z.2013.Beware of slowly slipping faults.Nature Geoscience,6:323-324.
滕吉文,白登海,杨辉等.2008.2008汶川MS8.0地震发生的深层过程和动力学响应.地球物理学报,51(5):1385-1402.
王辉,刘杰,石耀霖等.2008.鲜水河断裂带强震相互作用的动力学模拟研究.中国科学D辑:地球科学,38(7):808-818.
王卫民,赵连锋,李娟等.2008.四川汶川8.0级地震震源过程.地球物理学报,51(5):1403-1410.
徐晶,邵志刚,马宏生等.2013.鲜水河断裂带库仑应力演化与强震间关系.地球物理学报,56(4):1146-1158,doi:10.6038/cjg20130410.
岳中琦.2013.汶川地震与山崩地裂的极高压甲烷天然气成因和机理.地学前缘,20(6):15-20.