四川汶川Ms 8.0级地震的地表变形与同震位移
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摘要
四川汶川Ms 8.0级强烈地震与青藏高原东部松潘-甘孜地块东向挤出导致的龙门山活动断裂右旋斜冲运动存在动力学成因联系。沿龙门山中央北川-映秀断裂发育长度超过250km的地震变形带,由地震陡坎、地震鼓包、地震破裂、地震断层组成,形成了较大的同震位移。在震中区映秀地区观测到的最大同震位移为7.6m,由右旋走滑位移6.1m和垂直位移4.6m2个分量组成;虹口地区的右旋走滑位移为2.7m,垂直位移为4.6m,右旋斜冲总位移为5.3m;北川地区的右旋走滑位移为5.7m,垂直位移为3.4m,右旋斜冲总位移为6.6m;平通地区的右旋走滑位移为3.2m,垂直位移为3.0m,右旋斜冲总位移为4.4m。龙门山前缘的汉旺-漩口断裂及龙门山后缘的茂县-汶川断裂、青川断裂也发生了显著的同震断裂活动,但同震位移小于等于1.0m。根据同震位移实测数据和构造会聚速率的GPS观测资料,估算龙门山地区8.0级地震的复发周期为1150~2950年。
Dextral-slip thrusting of major active faults in Longmenshan Mts. related to eastward extrusion of Songpan-Ganzi terrain in eastern Tibetan Plateau caused the Ms 8.0 Wenchuan Earthquake. Seismic scarps, pressure ridges, seismic fractures and seismic faults formed along Beichuan-Yingxiu fault in central Longmenshan Mts., and extension of seismic zone along Beichuan-Yingxiu fault ex- ceeds 250km. Maximum co-seismic displacements with 6.1m dextral slip, 4.6m vertical displacement and 7.6m total displacement oc- curred in Yingxiu near the seismic epicenter. Co-seismic dextral slip, vertical displacement and total displacement along Yingxiu-Be- ichuan fault are respectively 2.7m, 4.6m and 5.3m in Hongkou, 5.7m, 3.4m and 6.6m in Beichuan, and 3.2m, 3.0m and 4.4m in Pingtong. Minor co-seismic displacement (less than 1.0m) formed along Hanwang-Xuankou fault in east Longmenshan Mts. and Maoxian-Wenchuan fault and Qingchuan fault in west Longmen Mts. though evident seismic faulting occurred along these active faults. Recurrence interval of Ms 8.0 earthquake in Longmen Mts. is estimated to be 1150-2950 years according to maximum co- seismic displacement and structural convergent rate determined by GPS.
Dextral-slip thrusting of major active faults in Longmenshan Mts. related to eastward extrusion of Songpan-Ganzi terrain in eastern Tibetan Plateau caused the Ms 8.0 Wenchuan Earthquake. Seismic scarps, pressure ridges, seismic fractures and seismic faults formed along Beichuan-Yingxiu fault in central Longmenshan Mts., and extension of seismic zone along Beichuan-Yingxiu fault ex- ceeds 250km. Maximum co-seismic displacements with 6.1m dextral slip, 4.6m vertical displacement and 7.6m total displacement oc- curred in Yingxiu near the seismic epicenter. Co-seismic dextral slip, vertical displacement and total displacement along Yingxiu-Be- ichuan fault are respectively 2.7m, 4.6m and 5.3m in Hongkou, 5.7m, 3.4m and 6.6m in Beichuan, and 3.2m, 3.0m and 4.4m in Pingtong. Minor co-seismic displacement (less than 1.0m) formed along Hanwang-Xuankou fault in east Longmenshan Mts. and Maoxian-Wenchuan fault and Qingchuan fault in west Longmen Mts. though evident seismic faulting occurred along these active faults. Recurrence interval of Ms 8.0 earthquake in Longmen Mts. is estimated to be 1150-2950 years according to maximum co- seismic displacement and structural convergent rate determined by GPS.
引文
[1]邓起东,于贵华,叶文华.地震地表破裂参数与震级关系的研究[C]//邓起东,汪一鹏.活动断裂研究(2).北京:地震出版社,1992:247-264.
[2]Zhao W,Nelson K D,Project INDEPTH Team.Deep seismic re-flection evidence for continental underthrusting beneath southern Ti-bet[J].Nature,1993,366:557-559.
[3]吴珍汉,吴中海,胡道功,等.青藏高原渐新世晚期隆升的地质证据[J].地质学报,2007,81(5):577-587.
[4]Tapponnier P,Molnar P.Active faulting and tectonics of China[J].Journal of Geophysical Research,1977,82:2905-2930.
[5]Chen Z,Burchfiel B C,Liu Y,et al.Global Positioning System measurement from eastern Tibet and its implications for India/Eurasia intercontinental deformation[J].Journal of Geophysical Research,2000,105:16215-16227.
[6]Yin A,Harrison T M.Geologic evolution of the Himalayan-Tibetan orogen[J].Annu.Rev.Earth Planet.Sci.Lett.,2000,28:211-280.
[7]Burchfiel B C,Chen Z,Liu Y,et al.Tectonics of the Longmen Shan and the adjacent regions,central China[J].International Geology Re-view,1995,37:661-735.
[8]Burchfiel B C,Royden L H,Van der Hilst R D,et al.A geological and geophysical context for the Wenchuan earthquake of May12,2008,Sichuan,People′s Republic of China[J].GSA Today,2008,18(7):doi.10.1130/GSATG18A1.
[9]Alexander L Densmore,Michael A Ellis,Li Yong,et al.Active tec-tonics of Beichuan and Pengguan faults at the eastern margin of the Tibetan Plateau[J].Tectonics,2007,26:TC4005,doi:10.1029/2006TC001987.
[10]Lin Aiming,Fu Bihong,Guo Jianming,et al.Co-seismic strike-slip and rupture length produced by the2001Ms8.1Central Kunlun Earthquake[J].Science,2002,296:2015-2017.
[11]Wu Zhenhan,Patrick J Barosh,Daogong Hu,et al.Hazards posed by active major faults along the Golmud-Lhasa railway route,Ti-betan Plateau,China[J].Engineering Geology,2004,74(3/4):163-182.
[12]中国地震局.中国昆仑山口西8.1级地震图集[M].北京:地震出版社,2003:1-105.
[13]吴珍汉,吴中海,胡道功,等.青藏铁路沿线活动断裂与地质灾害图集[M].北京:地震出版社,2005a:1-150.
[14]吴珍汉,胡道功,吴中海,等.青藏高原中段活动断层及诱发地质灾害[M].北京:地质出版社,2005b:1-385.
[15]Parsons Tom,Chen Ji,Eric Kirby.Stress changes from the2008Wenchuan earthquake and increased hazard in the Sichuan basin[J].Nature,2008,454:509-510,doi:10.1038/nature07177.
[16]张培震,王琪,马宗晋.青藏高原现今构造特征与GPS速度场[J].地学前缘,2002,9(2):442-450.
[17]张培震,王敏,甘卫军,等.GPS观测的活动断裂滑动速率及其对现今大陆动力作用的制约[J].地学前缘,2003,10(特刊):81-92.
[18]Zhang Peizhen,Shen Zhengkang,Wang Min,et al.Continous de-formation of the Tibetan Plateau from global positioning system data[J].Geology,2004,32(9):809-812.
[19]徐锡伟,陈文彬,于贵华,等.2001年11月14日昆仑山库赛湖地震(Ms8.1)地表破裂带的基本特征[J].地震地质,2002,24(1):1-13.
[20]吴中海,胡道功,吴珍汉.青藏铁路邻侧昆仑山2001年Ms8.1级地震地表破裂特征分析[J].地球学报,2004,25(4):411-414.
[21]国家地震局地质研究所.西藏中部活动断层[M].北京:地震出版社,1992:1-192.
[22]吴章明,申屠炳明,曹忠权,等.1411年西藏当雄8级地震地表破裂[J].地震地质,1990,12(2):98-108.
[2]Zhao W,Nelson K D,Project INDEPTH Team.Deep seismic re-flection evidence for continental underthrusting beneath southern Ti-bet[J].Nature,1993,366:557-559.
[3]吴珍汉,吴中海,胡道功,等.青藏高原渐新世晚期隆升的地质证据[J].地质学报,2007,81(5):577-587.
[4]Tapponnier P,Molnar P.Active faulting and tectonics of China[J].Journal of Geophysical Research,1977,82:2905-2930.
[5]Chen Z,Burchfiel B C,Liu Y,et al.Global Positioning System measurement from eastern Tibet and its implications for India/Eurasia intercontinental deformation[J].Journal of Geophysical Research,2000,105:16215-16227.
[6]Yin A,Harrison T M.Geologic evolution of the Himalayan-Tibetan orogen[J].Annu.Rev.Earth Planet.Sci.Lett.,2000,28:211-280.
[7]Burchfiel B C,Chen Z,Liu Y,et al.Tectonics of the Longmen Shan and the adjacent regions,central China[J].International Geology Re-view,1995,37:661-735.
[8]Burchfiel B C,Royden L H,Van der Hilst R D,et al.A geological and geophysical context for the Wenchuan earthquake of May12,2008,Sichuan,People′s Republic of China[J].GSA Today,2008,18(7):doi.10.1130/GSATG18A1.
[9]Alexander L Densmore,Michael A Ellis,Li Yong,et al.Active tec-tonics of Beichuan and Pengguan faults at the eastern margin of the Tibetan Plateau[J].Tectonics,2007,26:TC4005,doi:10.1029/2006TC001987.
[10]Lin Aiming,Fu Bihong,Guo Jianming,et al.Co-seismic strike-slip and rupture length produced by the2001Ms8.1Central Kunlun Earthquake[J].Science,2002,296:2015-2017.
[11]Wu Zhenhan,Patrick J Barosh,Daogong Hu,et al.Hazards posed by active major faults along the Golmud-Lhasa railway route,Ti-betan Plateau,China[J].Engineering Geology,2004,74(3/4):163-182.
[12]中国地震局.中国昆仑山口西8.1级地震图集[M].北京:地震出版社,2003:1-105.
[13]吴珍汉,吴中海,胡道功,等.青藏铁路沿线活动断裂与地质灾害图集[M].北京:地震出版社,2005a:1-150.
[14]吴珍汉,胡道功,吴中海,等.青藏高原中段活动断层及诱发地质灾害[M].北京:地质出版社,2005b:1-385.
[15]Parsons Tom,Chen Ji,Eric Kirby.Stress changes from the2008Wenchuan earthquake and increased hazard in the Sichuan basin[J].Nature,2008,454:509-510,doi:10.1038/nature07177.
[16]张培震,王琪,马宗晋.青藏高原现今构造特征与GPS速度场[J].地学前缘,2002,9(2):442-450.
[17]张培震,王敏,甘卫军,等.GPS观测的活动断裂滑动速率及其对现今大陆动力作用的制约[J].地学前缘,2003,10(特刊):81-92.
[18]Zhang Peizhen,Shen Zhengkang,Wang Min,et al.Continous de-formation of the Tibetan Plateau from global positioning system data[J].Geology,2004,32(9):809-812.
[19]徐锡伟,陈文彬,于贵华,等.2001年11月14日昆仑山库赛湖地震(Ms8.1)地表破裂带的基本特征[J].地震地质,2002,24(1):1-13.
[20]吴中海,胡道功,吴珍汉.青藏铁路邻侧昆仑山2001年Ms8.1级地震地表破裂特征分析[J].地球学报,2004,25(4):411-414.
[21]国家地震局地质研究所.西藏中部活动断层[M].北京:地震出版社,1992:1-192.
[22]吴章明,申屠炳明,曹忠权,等.1411年西藏当雄8级地震地表破裂[J].地震地质,1990,12(2):98-108.
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