汶川Ms8.0地震四川及邻区数字强震台网记录
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摘要
2008年5月12日汶川Ms8.0特大地震是龙门山构造带逆冲–右旋错动的结果,四川数字强震台网共获取133组三分向加速度记录,结合陕西、甘肃部分台站观测结果,根据原始记录绘制的加速度峰值等值线呈长轴为NE方向的不规则椭圆形,与地震影响烈度分布具有较好的一致性。进一步分析发现,该次地震的加速度记录具有比较明显的方向性效应和断层上盘效应,即沿破裂传播的NE方向加速度峰值衰减显著慢于SW方向;而处于断层NW上盘的地震动峰值衰减明显慢于SE下盘,出现系统性偏高现象,且在发震断裂的映秀—北川段更为显著,与震源破裂的方式和过程具相关性。另一个现象是近发震断裂的竖向(UD)与水平向(H)地震动峰值的比值明显高于远场,在近断层附近比值在1.0左右,与现行的《建筑抗震设计规范》(GB50011–2001)规定的比值2/3存在较大差异。随断层距的增加,加速度反应谱峰值逐渐移向长周期,当断层距大于200km时更为显著,但在近断层100km时存在速度大脉冲现象。
The thrust-dextral slip motion of Longmenshan tectonic belt resulted in Wenchuan Ms8.0 earthquake occurred on May 12,2008.133 groups of three-component acceleration records were collected by digital strong earthquake networks in Sichuan Province.By using these original records and some strong motion records from digital strong earthquake networks in Shaanxi and Gansu provinces,the contour lines of acceleration peak values were drawn;and they show that the anomalistic ellipse-shaped contour lines of acceleration peak values along the long axis in NE direction conform to the distribution of earthquake response intensity.The attenuation of the acceleration records shows obvious directivity effect and hanging wall effect;i.e.the peak acceleration decayed relatively slower in NE direction of the rupture propagation than in SW direction.The attenuation of peak acceleration also decayed slower on the fault hanging wall in NW direction than that in SE direction;the systemic relative higher phenomenon of the peak acceleration attenuation was more remarkable in Yingxiu—Beichuan section of the causative fault;and it can be relative to fracture pattern and progress of seismic source.Anotherphenomenon is that the ratio of vertical peak ground value to horizontal one near the causative fault is obviously higher than that in the seismic far-field;and the ratio is about 1.0 near the faults,which is great different with the 2/3 from Code for seismic design of buildings(GB50011-2001).Furthermore,with fault distance increasing,the peak acceleration gradually shifted to the long-period in the acceleration response spectrum,which is more obvious beyond a distance of 200 km to the causative faults;but in the near-fault distance of 100 km,there is a large velocity pulse.
The thrust-dextral slip motion of Longmenshan tectonic belt resulted in Wenchuan Ms8.0 earthquake occurred on May 12,2008.133 groups of three-component acceleration records were collected by digital strong earthquake networks in Sichuan Province.By using these original records and some strong motion records from digital strong earthquake networks in Shaanxi and Gansu provinces,the contour lines of acceleration peak values were drawn;and they show that the anomalistic ellipse-shaped contour lines of acceleration peak values along the long axis in NE direction conform to the distribution of earthquake response intensity.The attenuation of the acceleration records shows obvious directivity effect and hanging wall effect;i.e.the peak acceleration decayed relatively slower in NE direction of the rupture propagation than in SW direction.The attenuation of peak acceleration also decayed slower on the fault hanging wall in NW direction than that in SE direction;the systemic relative higher phenomenon of the peak acceleration attenuation was more remarkable in Yingxiu—Beichuan section of the causative fault;and it can be relative to fracture pattern and progress of seismic source.Anotherphenomenon is that the ratio of vertical peak ground value to horizontal one near the causative fault is obviously higher than that in the seismic far-field;and the ratio is about 1.0 near the faults,which is great different with the 2/3 from Code for seismic design of buildings(GB50011-2001).Furthermore,with fault distance increasing,the peak acceleration gradually shifted to the long-period in the acceleration response spectrum,which is more obvious beyond a distance of 200 km to the causative faults;but in the near-fault distance of 100 km,there is a large velocity pulse.
引文
[1]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.(WANG Weimin,ZHAO Lianfeng,LI Juan,et al.Rupture process of the Ms8.0Wenchuan earthquake of Sichuan,China[J].Chinese Journal of Geophysics,2008,51(5):1403-1410.(in Chinese))
[2]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.(ZHANG Yong,XU Lisheng,CHEN Yuntai.Spatio-temporal variation of the source mechanism of the2008great Wenchuan earthquake[J].Chinese Journal of Geophysics,2009,52(2):379-389.(in Chinese))
[3]PARSONS T,CHEN J,KIRBY E.Stress changes from the2008Wenchuan earthquake and increased hazard in the Sichuan basin[J].Nature,2008,454:509-510.
[4]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.(XU Xiwei,WEN Xueze,YE Jianqing,et al.The Ms8.0Wenchuan earthquake surface ruptures and its seismogenic structure[J].Seismology and Geology,2008,30(3):597-629.(in Chinese))
[5]周荣军,黄润秋,雷建成,等.四川汶川8.0级地震地表破裂与震害特点[J].岩石力学与工程学报,2008,27(11):2173-2183.(ZHOU Rongjun,HUANG Runqiu,LEI Jiancheng,et al.Surface rupture and hazard characteristics of Wenchuan earthquake with magnitude8.0in Sichuan Province[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(11):2173-2183.(in Chinese))
[6]李勇,周荣军,DENSMORE A L,等.映秀—北川断裂的地表破裂与变形特征[J].地质学报,2008,82(12):1688-1706.(LI Yong,ZHOU Rongjun,DENSMORE A L,et al.Surface rupture and deformation of the Yingxiu—Beichuan fault by the Wenchuan earthquake[J].Acta Geologica Sinica,2008,82(12):1688-1706.(in Chinese))
[7]何宏林,孙昭民,王世元,等.汶川MS8.0地震地表破裂带[J].地震地质,2008,30(2):359-362.(HE Honglin,SUN Zhaomin,WANG Shiyuan,et al.Rupture of the MS8.0Wenchuan earthquake[J].Seismology and Geology,2008,30(2):359-362.(in Chinese))
[8]李传友,魏占玉.汶川Ms8.0地震地表破裂带北端位置的修订[J].地震地质,2009,31(1):1-8.(LI Chuanyou,WEI Zhanyu.Deformation styles of the northernmost surface rupture zone of the Ms8.0Wenchuan earthquake[J].Seismology and Geology,2009,31(1):1-8.(in Chinese))
[9]杨晓平,李安,刘保金,等.成都平原内汶川Ms8.0级地震的地表变形[J].地球物理学报,2009,52(10):2527-2537.(YANG Xiaoping,LI An,LIU Baojin,et al.Surface deformation in the Chengdu plain area produced by the Wenchuan Ms8.0earthquake of12May2008,Sichuan,China[J].Chinese Journal of Geophysics,2009,52(10):2527-2537.(in Chinese))
[10]江娃利,谢新生,张景发,等.应用雷达卫星影像判读四川龙门山断裂带晚第四纪活动及其野外调查[C]//中国地震局地壳应力研究所编.汶川8.0级地震地壳动力学研究专辑.北京:地震出版社,2009:79-100.(JIANG Wali,XIE Xinsheng,ZHANG Jingfa,et al.Interpretation of activity of Longmenshan fault zone in Sichuan duringlate Quaternary based on the radar satellite images and surveying[C]//Institute of Crustal Dynamics,China Earthquake Administration ed.Crustal Dynamics of the Wenchuan Ms8.0Earthquake.Beijing:Earthquake Press,2009:79-100.(in Chinese))
[11]吴健,吕红山,刘爱文.汶川地震烈度分布与震源过程相关性的初步研究[J].震灾防御技术,2008,3(3):224-229.(WU Jian,LU Hongshan,LIU Aiwen.Preliminary study on correlation between seismic intensity and earthquake source process in Wenchuan earthquake of Sichuan,China[J].Technology for Earthquake Disaster Prevention,2008,3(3):224-229.(in Chinese))
[12]于海英,王栋,杨永强,等.汶川8.0级地震强震动特征初步分析[J].震灾防御技术,2008,3(4):321-336.(YU Haiying,WANG Dong,YANG Yongqiang,et al.The Preliminary analysis of strong ground motion characteristics from the Ms8.0Wenchuan earthquake,China[J].Technology for Earthquake Disaster Prevention,2008,3(4):321-336.(in Chinese))
[13]高孟潭,陈学良,俞言祥,等.“5.12”汶川8.0级地震汉源烈度异常机制的初步探讨[J].震灾防御技术,2008,3(3):216-223.(GAO Mengtan,CHEN Xueliang,YU Yanxiang,et al.Preliminary discussion on intensity anomalous mechanism of Hanyuan Town in5.12Wenchuan earthquake[J].Technology for Earthquake Disaster Prevention,2008,3(3):216-223.(in Chinese))
[14]SOMERVILLE P,SAIKIA C,WALD D,et al.Implications of the Northridge earthquake for strong ground motions from thrust faults[J].Bulletin of the Seismological Society of America,1996,86(1B):115-125.
[15]ABRAHAMSON N A,SOMERVILLE P G.Effects of the hanging wall and footwall on ground motions recorded during the Northridge earthquake[J].Bulletin of the Seismological Society of America,1996,86(1B):93-99.
[16]俞言祥,高孟潭.台湾集集地震近场地震动的上盘效应[J].地震学报,2001,21(6):615-621.(YU Yanxiang,GAO Mengtan.Effects of the hanging wall and footwall on peak acceleration during the Chichi earthquake,Taiwan[J].Acta Seismologica Sinica,2001,21(6):615-621.(in Chinese))
[17]黄润秋,李为乐.“5.12”汶川大地震触发地质灾害的发育分布规律研究[J].岩石力学与工程学报,2008,27(12):2585-2592.(Research on development and distribution rules of geohazards induced by Wenchuan earthquake on12th May,2008[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(12):2585-2592.(in Chinese))
[18]中华人民共和国国家标准编写组.GB50011-2001建筑抗震设计规范[S].北京:中国建筑工业出版社,2001.(The National Standards Compilation Group of People′s Republic of China.GB50011-2001Code for seismic design of buildings[S].Beijing:China Architecture and Building Press,2001.(in Chinese))
[2]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.(ZHANG Yong,XU Lisheng,CHEN Yuntai.Spatio-temporal variation of the source mechanism of the2008great Wenchuan earthquake[J].Chinese Journal of Geophysics,2009,52(2):379-389.(in Chinese))
[3]PARSONS T,CHEN J,KIRBY E.Stress changes from the2008Wenchuan earthquake and increased hazard in the Sichuan basin[J].Nature,2008,454:509-510.
[4]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.(XU Xiwei,WEN Xueze,YE Jianqing,et al.The Ms8.0Wenchuan earthquake surface ruptures and its seismogenic structure[J].Seismology and Geology,2008,30(3):597-629.(in Chinese))
[5]周荣军,黄润秋,雷建成,等.四川汶川8.0级地震地表破裂与震害特点[J].岩石力学与工程学报,2008,27(11):2173-2183.(ZHOU Rongjun,HUANG Runqiu,LEI Jiancheng,et al.Surface rupture and hazard characteristics of Wenchuan earthquake with magnitude8.0in Sichuan Province[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(11):2173-2183.(in Chinese))
[6]李勇,周荣军,DENSMORE A L,等.映秀—北川断裂的地表破裂与变形特征[J].地质学报,2008,82(12):1688-1706.(LI Yong,ZHOU Rongjun,DENSMORE A L,et al.Surface rupture and deformation of the Yingxiu—Beichuan fault by the Wenchuan earthquake[J].Acta Geologica Sinica,2008,82(12):1688-1706.(in Chinese))
[7]何宏林,孙昭民,王世元,等.汶川MS8.0地震地表破裂带[J].地震地质,2008,30(2):359-362.(HE Honglin,SUN Zhaomin,WANG Shiyuan,et al.Rupture of the MS8.0Wenchuan earthquake[J].Seismology and Geology,2008,30(2):359-362.(in Chinese))
[8]李传友,魏占玉.汶川Ms8.0地震地表破裂带北端位置的修订[J].地震地质,2009,31(1):1-8.(LI Chuanyou,WEI Zhanyu.Deformation styles of the northernmost surface rupture zone of the Ms8.0Wenchuan earthquake[J].Seismology and Geology,2009,31(1):1-8.(in Chinese))
[9]杨晓平,李安,刘保金,等.成都平原内汶川Ms8.0级地震的地表变形[J].地球物理学报,2009,52(10):2527-2537.(YANG Xiaoping,LI An,LIU Baojin,et al.Surface deformation in the Chengdu plain area produced by the Wenchuan Ms8.0earthquake of12May2008,Sichuan,China[J].Chinese Journal of Geophysics,2009,52(10):2527-2537.(in Chinese))
[10]江娃利,谢新生,张景发,等.应用雷达卫星影像判读四川龙门山断裂带晚第四纪活动及其野外调查[C]//中国地震局地壳应力研究所编.汶川8.0级地震地壳动力学研究专辑.北京:地震出版社,2009:79-100.(JIANG Wali,XIE Xinsheng,ZHANG Jingfa,et al.Interpretation of activity of Longmenshan fault zone in Sichuan duringlate Quaternary based on the radar satellite images and surveying[C]//Institute of Crustal Dynamics,China Earthquake Administration ed.Crustal Dynamics of the Wenchuan Ms8.0Earthquake.Beijing:Earthquake Press,2009:79-100.(in Chinese))
[11]吴健,吕红山,刘爱文.汶川地震烈度分布与震源过程相关性的初步研究[J].震灾防御技术,2008,3(3):224-229.(WU Jian,LU Hongshan,LIU Aiwen.Preliminary study on correlation between seismic intensity and earthquake source process in Wenchuan earthquake of Sichuan,China[J].Technology for Earthquake Disaster Prevention,2008,3(3):224-229.(in Chinese))
[12]于海英,王栋,杨永强,等.汶川8.0级地震强震动特征初步分析[J].震灾防御技术,2008,3(4):321-336.(YU Haiying,WANG Dong,YANG Yongqiang,et al.The Preliminary analysis of strong ground motion characteristics from the Ms8.0Wenchuan earthquake,China[J].Technology for Earthquake Disaster Prevention,2008,3(4):321-336.(in Chinese))
[13]高孟潭,陈学良,俞言祥,等.“5.12”汶川8.0级地震汉源烈度异常机制的初步探讨[J].震灾防御技术,2008,3(3):216-223.(GAO Mengtan,CHEN Xueliang,YU Yanxiang,et al.Preliminary discussion on intensity anomalous mechanism of Hanyuan Town in5.12Wenchuan earthquake[J].Technology for Earthquake Disaster Prevention,2008,3(3):216-223.(in Chinese))
[14]SOMERVILLE P,SAIKIA C,WALD D,et al.Implications of the Northridge earthquake for strong ground motions from thrust faults[J].Bulletin of the Seismological Society of America,1996,86(1B):115-125.
[15]ABRAHAMSON N A,SOMERVILLE P G.Effects of the hanging wall and footwall on ground motions recorded during the Northridge earthquake[J].Bulletin of the Seismological Society of America,1996,86(1B):93-99.
[16]俞言祥,高孟潭.台湾集集地震近场地震动的上盘效应[J].地震学报,2001,21(6):615-621.(YU Yanxiang,GAO Mengtan.Effects of the hanging wall and footwall on peak acceleration during the Chichi earthquake,Taiwan[J].Acta Seismologica Sinica,2001,21(6):615-621.(in Chinese))
[17]黄润秋,李为乐.“5.12”汶川大地震触发地质灾害的发育分布规律研究[J].岩石力学与工程学报,2008,27(12):2585-2592.(Research on development and distribution rules of geohazards induced by Wenchuan earthquake on12th May,2008[J].Chinese Journal of Rock Mechanics and Engineering,2008,27(12):2585-2592.(in Chinese))
[18]中华人民共和国国家标准编写组.GB50011-2001建筑抗震设计规范[S].北京:中国建筑工业出版社,2001.(The National Standards Compilation Group of People′s Republic of China.GB50011-2001Code for seismic design of buildings[S].Beijing:China Architecture and Building Press,2001.(in Chinese))
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