汶川M_s 8.0级地震强震记录所揭示的地震断层特征分析
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摘要
基于2008年5月12日汶川Ms8.0级地震的强震台站记录,对比发震断层两侧的峰值加速度与地表破裂带上同震位移的分布特点,探讨了地震动强度分布特征与地表破裂位移分布之间的相关关系。分析近断层典型台站的强震动记录时程特征,获得了强地震动记录中所包含的断层破裂过程和破裂习性信息,从强震观测记录的角度进一步证实了汶川地震主震的多次破裂特征。结果表明,汶川地震主震至少包含了4次地震破裂事件,最主要的前两次破裂事件分别对应映秀—北川断裂段和北川—南坝断裂段的破裂过程,后两次破裂事件释放的能量相对较小,应该是第二次破裂过程触发局部次级破裂所引起的。此外,垂直于断层的峰值加速度剖面揭示的发震断层的高倾角逆冲特性,与地震地质调查和小震精定位等确定的相应结果是一致的。
Based on analysis of strong motion records of Wenchuan Ms 8.0 earthquake on May 12,2008,we compared and discussed the distribution characteristics of peak ground acceleration(PGA) and coseismic displacements to disclose the correlation between earthquake intensity distribution and surface rupture.From the recording waveforms of typical near-fault strong motion stations,we can extract valuable information of fault rupture process and behaviors contained in acceleration time-histories,which further confirmed the multi-rupture process by means of strong motion observation.The results show that the Wenchuan earthquake contained at least 4 times of rupture events during the whole process.The most important first two events corresponded respectively to ruptures occurred in the Yingxiu-Beichuan fault and the Beichuan-Nanba fault.The other two events,in which the energy released was relatively small,were triggered probably by the second rupture event occurred on the Beichuan-Nanba fault.In addition,the peak acceleration perpendicular to the fault indicated that the causative fault was a high-angle reverse fault,which is consistent with the results of geological survey and aftershock relocation.
Based on analysis of strong motion records of Wenchuan Ms 8.0 earthquake on May 12,2008,we compared and discussed the distribution characteristics of peak ground acceleration(PGA) and coseismic displacements to disclose the correlation between earthquake intensity distribution and surface rupture.From the recording waveforms of typical near-fault strong motion stations,we can extract valuable information of fault rupture process and behaviors contained in acceleration time-histories,which further confirmed the multi-rupture process by means of strong motion observation.The results show that the Wenchuan earthquake contained at least 4 times of rupture events during the whole process.The most important first two events corresponded respectively to ruptures occurred in the Yingxiu-Beichuan fault and the Beichuan-Nanba fault.The other two events,in which the energy released was relatively small,were triggered probably by the second rupture event occurred on the Beichuan-Nanba fault.In addition,the peak acceleration perpendicular to the fault indicated that the causative fault was a high-angle reverse fault,which is consistent with the results of geological survey and aftershock relocation.
引文
①中国地震局震害防御司.中国数字强震动台网工程技术报告[R].中国数字地震观测网络项目验收报告,2008.
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[2]Xu X W,Wen X Z,Yu G H,et al.Co-seismic reverse-andoblique-slip surface faulting generated by the 2008Mw7.9Wenchuan earthquake,China[J].Geology,2009,37(6):515-518.
[3]Chen Y T,Xu L S,Zhang Y,et al.Analysis Report on Fo-cal Characteristics of the Wenchuan Strong Earthquake onMay 12,2008[R].[2009-06-01]http:∥www.csi.ac.cn/Si-chuan/chenyuntai.pdf.2008(in Chinese).
[4]Parsons T,Ji C,Kirby E.Stress changes from the 2008Wenchuan earthquake andincreased hazardinthe Sichuan Ba-sin[J].Nature,2008,454:509-510.
[5]Wang W M,Zhao L F,Li J,et al.Rupture process of theMs8.0 Wenchuan earthquake of Sichuan,China[J].ChineseJournal of Geophysics,2008,51(5):1403-1410(in Chi-nese).
[6]Zhang Y,Xu L S,Chen Y T.Spatio-temporal variation ofthe source mechanismof the 2008 great Wenchuan earthquake[J].Chinese Journal of Geophysics,2009,52(2):379-389(in Chinaese).
[7]Ji C,Hayes G.Preli minary Result of the May 12,2008Mw7.9 Eastern Sichuan,China Earthquake[R].[2010-04-01]http:∥earthquake.usgs.gov/eqcenter/eqinthenews/2008/us2008ryan/finite_fault.php.
[8]Wang M.Coseismic slip distribution of the 2008 Wenchuangreat earthquake constrained using GPS coseismic displace-ment field[J].Chinese Journal of Geophysics,2009,52(10):2519-2526(in Chinese).
[9]Li XJ,Zhou Z H,Yu H Y,et al.Strong motion observa-tions and recordings from the great Wenchuan Earthquake[J].Earthquake Engineering and Engineering Vibration,2008,7(3):235-246.
[10]Xu Z Q,Li H Q,Hou L W,et al.Up lift of the LongmenJinping orogenic belt along the eastern margin of the Qinghai-Tibet Plateau:Large scale detachment faulting and extrusionmechanism[J].Geological Bulletin of China,2007,26(10):1262-1276(in Chinese).
[11]Deng Q D,Chen S F,Zhao X L.Tectonics,seismicity anddynamics of Longmen Shan Mountains and its adjacent re-gions[J].Seismology and Geology,1994,16(4):389-403(inChinese).
[12]Zhang P Z,Wen X Z,Shen Z K,et al.Oblique,high-angle,listric-reverse faulting and associated development of strain:The Wenchuan earthquake of May 12,2008,Sichuan,China[J].The Annual Review of Earth and Planetary Sciences,2010,38:353-382.
[13]Jia D,Wei G,Chen Z,et al.Longmen Shan fold-thrust beltandits relationto the western Sichuan Basinin central China:Newinsights fromhydrocarbon exploration[J].AAPG Bulle-tin,2006,90:1425-1447.
[14]Xu X W,Wen X Z,Ye J Q,et al.TheMs8.0 Wenchuanearthquake surface ruptures andits seismogenic structure[J].Seismology and Geology,2008,30(3):597-629(in Chi-nese).
[15]Zhang P Z,Wen X Z,Xu X W,et al.Tectonic model of thegreat Wenchuan earthquake of May 12,2008,Sichuan,Chi-na[J].Chinese Science Bulletin,2009,54(7):944-953(inChinese).
[16]Chen J H,Liu Q Y,Li S C,et al.Seismotectonic study byrelocation of the WenchuanMs8.0 earthquake sequence[J].Chinese Journal of Geophysics,2009,52(2):390-397(inChinese).
[17]Li Z Q,Yuan YF,Li X L,et al.Preli minary research onthecharacteristics of theMs8.0 Wenchuan earthquake hazard[J].Seismology and Geology,2008,30(4):855-876(in Chi-nese).
[18]Zhou Z H,Zhou Y N,Lu T,et al.Study on characteristicsof vertical ground motion[J].Earthquake Engineering andEngineering Vibration,2003,23(3):25-29(in Chinese).
[19]Zhang D L,Zhang W,Xu X W,et al.Influence of seismicsource rupture mode on strong ground motion in YinchuanBasin[J].Earthquake Engineering and Engineering Vibra-tion,2009,29(4):1-8(in Chinese).
[20]Wang G Q.The Characteristics of Near Fault Ground MotionCaused by the 1999,Chi-Chi,Tai wan Earthquake[D].Bei-jing:Institute of Geology,China Earthquake Administration,2001(in Chinese).
[1]中国地震信息网.四川汶川县Ms8.0地震参数[R].http:∥www.csi.ac.cn/Sichuan/Sichuan 082_cs1.ht m.2008.
[3]陈运泰,许力生,张勇,等.2008年5月12日汶川特大地震震源特性分析报告[R].[2009-06-01]http:∥www.csi.ac.cn/Sichuan/chenyuntai.pdf.2008.
[5]王卫民,赵连锋,李娟,等.四川汶川8.0级地震震源过程[J].地球物理学报,2008,51(5):1403-1410.
[6]张勇,许力生,陈运泰.2008年汶川大地震震源机制的时空变化[J].地球物理学报,2009,52(2):379-389.
[8]王敏.基于GPS同震位移场约束反演2008年5.12汶川大地震破裂空间分布[J].地球物理学报,2009,52(10):2519-2526.
[10]许志琴,李化启,侯立玮,等.青藏高原东缘龙门山—锦屏造山带的崛起:大型拆离断层和挤出机制[J].地质通报,2007,26(10):1262-1276.
[11]邓起东,陈社发,赵小麟.龙门山及其邻区的构造和地震活动及动力学[J].地震地质,1994,16(4):389-403.
[14]徐锡伟,闻学泽,叶建青,等.汶川Ms8.0地震地表破裂带及其发震构造[J].地震地质,2008,30(3):597-629.
[15]张培震,闻学泽,徐锡伟,等.2008年汶川8.0级特大地震孕育和发生的多单元组合模式[J].科学通报,2009,54(7):944-953.
[16]陈九辉,刘启元,李顺成,等.汶川Ms8.0地震余震序列重新定位及其地震构造研究[J].地球物理学报,2009,52(2):390-397.
[17]李志强,袁一凡,李晓丽,等.汶川Ms8.0特大地震破坏特征初步研究[J].地震地质,2008,30(4):855-876.
[18]周正华,周雍年,卢滔,等.竖向地震动特征研究[J].地震工程与工程振动,2003,23(3):25-29.
[19]张冬丽,张伟,徐锡伟,等.断层破裂方式对银川盆地强地面运动的影响[J].地震工程与工程振动,2009,29(4):1-8.
[20]王国权.9.21台湾集集地震近断层地面运动特征[D].北京:中国地震局地质研究所,2001.
[1]China Seismic Information Net.Seismological Parameters fortheMs8.0 Wenchuan Earthquake,Sichuan[R].http:∥www.csi.ac.cn/sichuan/Sichuan 080 512_cs1.ht m,2008(inChinese).
[2]Xu X W,Wen X Z,Yu G H,et al.Co-seismic reverse-andoblique-slip surface faulting generated by the 2008Mw7.9Wenchuan earthquake,China[J].Geology,2009,37(6):515-518.
[3]Chen Y T,Xu L S,Zhang Y,et al.Analysis Report on Fo-cal Characteristics of the Wenchuan Strong Earthquake onMay 12,2008[R].[2009-06-01]http:∥www.csi.ac.cn/Si-chuan/chenyuntai.pdf.2008(in Chinese).
[4]Parsons T,Ji C,Kirby E.Stress changes from the 2008Wenchuan earthquake andincreased hazardinthe Sichuan Ba-sin[J].Nature,2008,454:509-510.
[5]Wang W M,Zhao L F,Li J,et al.Rupture process of theMs8.0 Wenchuan earthquake of Sichuan,China[J].ChineseJournal of Geophysics,2008,51(5):1403-1410(in Chi-nese).
[6]Zhang Y,Xu L S,Chen Y T.Spatio-temporal variation ofthe source mechanismof the 2008 great Wenchuan earthquake[J].Chinese Journal of Geophysics,2009,52(2):379-389(in Chinaese).
[7]Ji C,Hayes G.Preli minary Result of the May 12,2008Mw7.9 Eastern Sichuan,China Earthquake[R].[2010-04-01]http:∥earthquake.usgs.gov/eqcenter/eqinthenews/2008/us2008ryan/finite_fault.php.
[8]Wang M.Coseismic slip distribution of the 2008 Wenchuangreat earthquake constrained using GPS coseismic displace-ment field[J].Chinese Journal of Geophysics,2009,52(10):2519-2526(in Chinese).
[9]Li XJ,Zhou Z H,Yu H Y,et al.Strong motion observa-tions and recordings from the great Wenchuan Earthquake[J].Earthquake Engineering and Engineering Vibration,2008,7(3):235-246.
[10]Xu Z Q,Li H Q,Hou L W,et al.Up lift of the LongmenJinping orogenic belt along the eastern margin of the Qinghai-Tibet Plateau:Large scale detachment faulting and extrusionmechanism[J].Geological Bulletin of China,2007,26(10):1262-1276(in Chinese).
[11]Deng Q D,Chen S F,Zhao X L.Tectonics,seismicity anddynamics of Longmen Shan Mountains and its adjacent re-gions[J].Seismology and Geology,1994,16(4):389-403(inChinese).
[12]Zhang P Z,Wen X Z,Shen Z K,et al.Oblique,high-angle,listric-reverse faulting and associated development of strain:The Wenchuan earthquake of May 12,2008,Sichuan,China[J].The Annual Review of Earth and Planetary Sciences,2010,38:353-382.
[13]Jia D,Wei G,Chen Z,et al.Longmen Shan fold-thrust beltandits relationto the western Sichuan Basinin central China:Newinsights fromhydrocarbon exploration[J].AAPG Bulle-tin,2006,90:1425-1447.
[14]Xu X W,Wen X Z,Ye J Q,et al.TheMs8.0 Wenchuanearthquake surface ruptures andits seismogenic structure[J].Seismology and Geology,2008,30(3):597-629(in Chi-nese).
[15]Zhang P Z,Wen X Z,Xu X W,et al.Tectonic model of thegreat Wenchuan earthquake of May 12,2008,Sichuan,Chi-na[J].Chinese Science Bulletin,2009,54(7):944-953(inChinese).
[16]Chen J H,Liu Q Y,Li S C,et al.Seismotectonic study byrelocation of the WenchuanMs8.0 earthquake sequence[J].Chinese Journal of Geophysics,2009,52(2):390-397(inChinese).
[17]Li Z Q,Yuan YF,Li X L,et al.Preli minary research onthecharacteristics of theMs8.0 Wenchuan earthquake hazard[J].Seismology and Geology,2008,30(4):855-876(in Chi-nese).
[18]Zhou Z H,Zhou Y N,Lu T,et al.Study on characteristicsof vertical ground motion[J].Earthquake Engineering andEngineering Vibration,2003,23(3):25-29(in Chinese).
[19]Zhang D L,Zhang W,Xu X W,et al.Influence of seismicsource rupture mode on strong ground motion in YinchuanBasin[J].Earthquake Engineering and Engineering Vibra-tion,2009,29(4):1-8(in Chinese).
[20]Wang G Q.The Characteristics of Near Fault Ground MotionCaused by the 1999,Chi-Chi,Tai wan Earthquake[D].Bei-jing:Institute of Geology,China Earthquake Administration,2001(in Chinese).
[1]中国地震信息网.四川汶川县Ms8.0地震参数[R].http:∥www.csi.ac.cn/Sichuan/Sichuan 082_cs1.ht m.2008.
[3]陈运泰,许力生,张勇,等.2008年5月12日汶川特大地震震源特性分析报告[R].[2009-06-01]http:∥www.csi.ac.cn/Sichuan/chenyuntai.pdf.2008.
[5]王卫民,赵连锋,李娟,等.四川汶川8.0级地震震源过程[J].地球物理学报,2008,51(5):1403-1410.
[6]张勇,许力生,陈运泰.2008年汶川大地震震源机制的时空变化[J].地球物理学报,2009,52(2):379-389.
[8]王敏.基于GPS同震位移场约束反演2008年5.12汶川大地震破裂空间分布[J].地球物理学报,2009,52(10):2519-2526.
[10]许志琴,李化启,侯立玮,等.青藏高原东缘龙门山—锦屏造山带的崛起:大型拆离断层和挤出机制[J].地质通报,2007,26(10):1262-1276.
[11]邓起东,陈社发,赵小麟.龙门山及其邻区的构造和地震活动及动力学[J].地震地质,1994,16(4):389-403.
[14]徐锡伟,闻学泽,叶建青,等.汶川Ms8.0地震地表破裂带及其发震构造[J].地震地质,2008,30(3):597-629.
[15]张培震,闻学泽,徐锡伟,等.2008年汶川8.0级特大地震孕育和发生的多单元组合模式[J].科学通报,2009,54(7):944-953.
[16]陈九辉,刘启元,李顺成,等.汶川Ms8.0地震余震序列重新定位及其地震构造研究[J].地球物理学报,2009,52(2):390-397.
[17]李志强,袁一凡,李晓丽,等.汶川Ms8.0特大地震破坏特征初步研究[J].地震地质,2008,30(4):855-876.
[18]周正华,周雍年,卢滔,等.竖向地震动特征研究[J].地震工程与工程振动,2003,23(3):25-29.
[19]张冬丽,张伟,徐锡伟,等.断层破裂方式对银川盆地强地面运动的影响[J].地震工程与工程振动,2009,29(4):1-8.
[20]王国权.9.21台湾集集地震近断层地面运动特征[D].北京:中国地震局地质研究所,2001.
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