汶川M_S8.0地震灾害的非对称分布与成因分析
|
摘要
在汶川MS8.0地震中,地震灾害在灾区相对于发震断层,呈现各种非对称分布.断层高角度逆冲诱发的崩塌、滑坡的规模与数量在断层上盘区远远高于断层下盘区,在垂直断层方向,高烈度区断层上盘宽度往往大于下盘宽度,上述不对称性反映了逆断层型地震存在加速度峰值的上盘效应;而在破裂的传播方向存在的地震波多普勒效应则造成沿长轴方向东北部烈度衰减变慢、西南部烈度衰减变快;在山地与盆地过渡地带及盆地平原区,大范围的房屋受损、人员伤亡,则很可能为场地土层放大与盆地效应等所致;紧邻地表破裂带一些建筑物没有倒塌的事实表明,除建筑物的抗震性能存在差异外,还存在产生地表破裂的浅部有效应力降和破裂速率相对降低,导致1 s附近的地震动相对低下的可能性;而地表强变形带宽度较窄除破裂带处地震动相对较低外,地震断层倾角在地表变陡则是另一重要原因.
Seismic disasters displayed various asymmetrical distribution during the 2008 MS8.0 Whenchuan earthquake.The size and quantity of landslides and rock avalanches triggered by high-angle reverse faulting on the hanging wall are higher than on the footwall.In the direction perpendicular to fault strike,the zones with high intensity on the hanging wall are wider than on the footwall.These asymmetries reflect hanging wall effect on peak ground acceleration in reverse faulting event.In the direction of rupture propagation,Doppler effect induced intensity attenuating slowly northeastward and rapidly southwestward.In the region between mountain and basin,heavy casualties and serious destruction of buildings are probably caused by site magnification and basin effect.Possible reason for the buildings near surface rupture zone having withstood the strong earthquake is that the effective stress drop and rupture velocity generation surface fractures may be low there,resulting in a relatively low ground motion around the period of 1 sec.The near-surface seismogenic fault being steep is another reason for the fact that the surface intense deformation zone is narrow.
Seismic disasters displayed various asymmetrical distribution during the 2008 MS8.0 Whenchuan earthquake.The size and quantity of landslides and rock avalanches triggered by high-angle reverse faulting on the hanging wall are higher than on the footwall.In the direction perpendicular to fault strike,the zones with high intensity on the hanging wall are wider than on the footwall.These asymmetries reflect hanging wall effect on peak ground acceleration in reverse faulting event.In the direction of rupture propagation,Doppler effect induced intensity attenuating slowly northeastward and rapidly southwestward.In the region between mountain and basin,heavy casualties and serious destruction of buildings are probably caused by site magnification and basin effect.Possible reason for the buildings near surface rupture zone having withstood the strong earthquake is that the effective stress drop and rupture velocity generation surface fractures may be low there,resulting in a relatively low ground motion around the period of 1 sec.The near-surface seismogenic fault being steep is another reason for the fact that the surface intense deformation zone is narrow.
引文
陈桂华,徐锡伟,郑荣章,于贵华,李峰,李陈侠,闻学泽,何玉林,叶友青,陈献程,王志才.2008.2008年汶川MS8.0地震地表破裂变形定量分析:北川-映秀断裂地表破裂带[J].地震地质,30(3):723--737.
陈运泰,许力生,张勇,杜海林,冯万鹏,刘超,李春来.2008.2008年5月12日汶川特大地震震源特性分析报告[R/OL].[2008-05-30].http:∥www.csi.ac.cn/sichuan/chenyuntai.pdf
郭恩栋,邵广彪.2002.正、逆断层覆盖土层地震断裂对比研究[M]∥王椿镛,齐霄斋主编.新世纪地震工程与防震减灾.北京:地震出版社:179--184.
韩竹军,冉勇康,徐锡伟.2002.隐伏活动断层未来地表破裂带宽度与位错量初步研究[J].地震地质,24(4):484--494.
何宏林,孙昭民,魏占玉,董绍鹏,高翔,王世元,王纪强.2008.汶川MS8.0级地震地表破裂带白沙河段破裂及其位移特征[J].地震地质,30(3):658--673.
黄润秋,李为乐.2009.汶川大地震触发地质灾害的断层效应分析[J].工程地质学报,17(1):19--28.
胡聿贤.2006.地震工程学[M].北京:地震出版社:54--56.
徐锡伟,闻学泽,叶建青,马保起,陈杰,周荣军,何宏林,田勤俭,何玉林,王志才,孙昭民,冯希杰,于贵华,陈立春,陈桂华,于慎鄂,冉勇康,李细光,李陈侠,安艳芬.2008.汶川MS8.0地震地表破裂带及其发震构造[J].地震地质,30(3):597--629.
殷跃平.2009.汶川八级地震滑坡特征分析[J].工程地质学报,17(1):29--38.
俞言祥,高孟潭.2001.台湾集集地震近场地震动的上盘效应[J].地震学报,23(6):615--621.
袁一凡.2008.四川汶川8.0级地震损失评估[J].地震工程与工程振动,28(5):10--19.
赵伯明,徐锡伟.2008.汶川8.0地震断层与地震灾害初步分析[J].地震地质,30(4):839--854.
张培震,闻学泽,徐锡伟,甘卫军,王敏,沈正康,王庆良,黄媛,郑勇,李小军,张竹琪,马胜利,冉勇康,刘启元,丁志峰,吴建平.2009.2008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,54(7):944--953.
周庆,徐锡伟,于贵华,陈献程,何宏林,尹功明.2008.汶川8.0级地震地表破裂带宽度调查[J].地震地质,30(3):778--787.
Abrahamson N A,Somerville P G.1996.Effects of the hanging wall andfootwall on ground motions recorded duringtheNorthridge earthquake[J].Bull Seism Soc Amer,86(1B):S93--S99.
Dalguer L A,Irikura K,Riera J D.2003.Simulation of tensile crack generation by three-dimensional dynamic shear rup-ture propagation during an earthquake[J].J Geophys Res,108(B3):2144,doi:10.1029/2001JB001738.
Idriss J M.1978.Characteristics of earthquake ground motion[C]∥Earthquake Engineering and Soil Dynamics.SanFrancisco:Woodward-Clyde Consultants.3:1151--1265.
Kagawa T,Irikura K,Somerville P.2004a.Differences in ground motion and fault rupture process between the surfaceand buried rupture earthquakes[J].Earth Planets and Space,56:3--14.
Kagawa T,Zhao B M,Miyakoshi K,Irikura K.2004b.Modeling of3D basin structures for seismic wave simulationsbased on available information on the target area:Case study of the Osaka Basin,Japan[J].Bull Seism Soc Amer,94(4):1353--1368.
Li XJ,Zhou Z H,Huang M,Wen R Z,Yu H Y,Lu D W,Zhou Y N,Cui J W.2008.Preliminary analysis of strong-motion recordings fromthe magnitude8.0Wenchuan,China,earthquake of12May2008[J].Seism Res Lett,79(6):844--854.
Somerville P G,Smith NF,Graves R W,Abrahamson N A.1997.Modification of empirical strong ground motion atten-uation relations toinclude the amplitude and duration effects of rupture direction[J].Seis Res Lett,68(1):199--222.
Somerville P G,Irikura K,Graves R,Sawada S,Wald D,Abrahamson N,Iwasaki Y,Kagawa T,Smith N,Kowada A.1999.Characterizing crustal earthquake slip models for the prediction of strong ground motion[J].Seism Res Lett,70(1):59--80.
陈运泰,许力生,张勇,杜海林,冯万鹏,刘超,李春来.2008.2008年5月12日汶川特大地震震源特性分析报告[R/OL].[2008-05-30].http:∥www.csi.ac.cn/sichuan/chenyuntai.pdf
郭恩栋,邵广彪.2002.正、逆断层覆盖土层地震断裂对比研究[M]∥王椿镛,齐霄斋主编.新世纪地震工程与防震减灾.北京:地震出版社:179--184.
韩竹军,冉勇康,徐锡伟.2002.隐伏活动断层未来地表破裂带宽度与位错量初步研究[J].地震地质,24(4):484--494.
何宏林,孙昭民,魏占玉,董绍鹏,高翔,王世元,王纪强.2008.汶川MS8.0级地震地表破裂带白沙河段破裂及其位移特征[J].地震地质,30(3):658--673.
黄润秋,李为乐.2009.汶川大地震触发地质灾害的断层效应分析[J].工程地质学报,17(1):19--28.
胡聿贤.2006.地震工程学[M].北京:地震出版社:54--56.
徐锡伟,闻学泽,叶建青,马保起,陈杰,周荣军,何宏林,田勤俭,何玉林,王志才,孙昭民,冯希杰,于贵华,陈立春,陈桂华,于慎鄂,冉勇康,李细光,李陈侠,安艳芬.2008.汶川MS8.0地震地表破裂带及其发震构造[J].地震地质,30(3):597--629.
殷跃平.2009.汶川八级地震滑坡特征分析[J].工程地质学报,17(1):29--38.
俞言祥,高孟潭.2001.台湾集集地震近场地震动的上盘效应[J].地震学报,23(6):615--621.
袁一凡.2008.四川汶川8.0级地震损失评估[J].地震工程与工程振动,28(5):10--19.
赵伯明,徐锡伟.2008.汶川8.0地震断层与地震灾害初步分析[J].地震地质,30(4):839--854.
张培震,闻学泽,徐锡伟,甘卫军,王敏,沈正康,王庆良,黄媛,郑勇,李小军,张竹琪,马胜利,冉勇康,刘启元,丁志峰,吴建平.2009.2008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,54(7):944--953.
周庆,徐锡伟,于贵华,陈献程,何宏林,尹功明.2008.汶川8.0级地震地表破裂带宽度调查[J].地震地质,30(3):778--787.
Abrahamson N A,Somerville P G.1996.Effects of the hanging wall andfootwall on ground motions recorded duringtheNorthridge earthquake[J].Bull Seism Soc Amer,86(1B):S93--S99.
Dalguer L A,Irikura K,Riera J D.2003.Simulation of tensile crack generation by three-dimensional dynamic shear rup-ture propagation during an earthquake[J].J Geophys Res,108(B3):2144,doi:10.1029/2001JB001738.
Idriss J M.1978.Characteristics of earthquake ground motion[C]∥Earthquake Engineering and Soil Dynamics.SanFrancisco:Woodward-Clyde Consultants.3:1151--1265.
Kagawa T,Irikura K,Somerville P.2004a.Differences in ground motion and fault rupture process between the surfaceand buried rupture earthquakes[J].Earth Planets and Space,56:3--14.
Kagawa T,Zhao B M,Miyakoshi K,Irikura K.2004b.Modeling of3D basin structures for seismic wave simulationsbased on available information on the target area:Case study of the Osaka Basin,Japan[J].Bull Seism Soc Amer,94(4):1353--1368.
Li XJ,Zhou Z H,Huang M,Wen R Z,Yu H Y,Lu D W,Zhou Y N,Cui J W.2008.Preliminary analysis of strong-motion recordings fromthe magnitude8.0Wenchuan,China,earthquake of12May2008[J].Seism Res Lett,79(6):844--854.
Somerville P G,Smith NF,Graves R W,Abrahamson N A.1997.Modification of empirical strong ground motion atten-uation relations toinclude the amplitude and duration effects of rupture direction[J].Seis Res Lett,68(1):199--222.
Somerville P G,Irikura K,Graves R,Sawada S,Wald D,Abrahamson N,Iwasaki Y,Kagawa T,Smith N,Kowada A.1999.Characterizing crustal earthquake slip models for the prediction of strong ground motion[J].Seism Res Lett,70(1):59--80.
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心