2008年汶川地震近断层竖向与水平向地震动特征
|
摘要
选取分布在北川映秀中央断裂两侧断层距120 km以内的40个强震动台站的记录,对汶川地震近断层地震动竖向和水平向加速度峰值、速度峰值、竖向和水平向加速度反应谱及谱比值进行了统计分析.研究表明:(1)地震动加速度峰值有显著的上盘效应,经验衰减模型的结果表明,在距地表破裂3～60 km的范围内,龙门山发震断层上盘一侧竖向与水平向的加速度峰值要比衰减模型得到的平均值大30%～40%.上盘的加速度峰值残差大部分是正值,而断层下盘残差大部分为负;水平地震动的东西分量幅值总体要大于南北分量,东西分量衰减相对较慢.(2)地震动长周期成分较弱,加速度反应谱值随周期增大而迅速减小,在周期1.0 s时,即使在靠近中央断裂的最大加速度反应谱值也只有0.5 g;地震动加速度反应谱谱比值(竖向/水平向)沿龙门山断层周围的分布,在较长周期(T=0.2 s,0.5 s,1.0 s)与短周期(T=0.05 s,0.1 s)有明显的不同.(3)近断层竖向地震动显著,地震动加速度峰值比在(竖向/水平向)可达1.4.在龙门山发震断层的上盘,地震动加速度峰值比整体上比下盘要大,竖向地震动尤为剧烈.部分近断层记录的地震动谱比值(竖向/水平向)在短周期(<0.1 s)甚至超过1.5,统计分析还表明谱比值在短周期段(<0.1 s)随断层距的增大而减小.
Characteristics of near-fault vertical and horizontal ground motion from 2008 Wenchuan earthquake are investigated in this paper.Records from 40 strong motion stations along the Beichuan-Yingxiu fault with fault distance smaller than 120 km are used as database.Based on the analysis of peak ground acceleration,peak velocity,spectra acceleration and spectra ratio of vertical to horizontal ground motion,the following conclusions can be made:(1) Hanging wall effects are shown in PGA for near-fault ground motions within 60km to the fault rupture,the empirical model results in up to a 30%—40% increase in peak horizontal and vertical accelerations on the hanging wall over the distance range of 3 to 60km relative to the median attenuation for the Wenchuan earthquake.The peak acceleration residuals on the hanging wall appear to be biased to positive values whereas the residuals for footwall sites are negative.The EW component of horizontal accelerations is larger than the NS component and attenuates more slowly.(2) There is a lack of long period component in near-fault ground motion of Wenchuan earthquake,the value of spectrum acceleration decrease rapidly in the long period range.The maximum spectrum acceleration is only 0.5g even at locations very close to the main causative fault at period 1.0 s. Large distinctions are shown in the distribution of acceleration spectrum ratio (Vertical/ Horizontal) for near-source ground motion at longer periods (T=0.2 s,0.5 s,1.0 s) with respect to short periods (T=0.05 s,0.1 s).(3) High intensity of UD component is shown for near-fault ground motion,the PGA ratio (Vertical/Horizontal) can be as large as 1.4.High intensity of UD component is more obvious on the hanging wall,and the PGA ratios on the hanging wall are much larger compared with the footwall.For some near-fault records,the acceleration spectrum ratio (Vertical/Horizontal) can even be larger than 1.5.It can also be concluded that the acceleration spectrum ratio decrease with the increasing of fault distance at short periods (<0.1 s).
Characteristics of near-fault vertical and horizontal ground motion from 2008 Wenchuan earthquake are investigated in this paper.Records from 40 strong motion stations along the Beichuan-Yingxiu fault with fault distance smaller than 120 km are used as database.Based on the analysis of peak ground acceleration,peak velocity,spectra acceleration and spectra ratio of vertical to horizontal ground motion,the following conclusions can be made:(1) Hanging wall effects are shown in PGA for near-fault ground motions within 60km to the fault rupture,the empirical model results in up to a 30%—40% increase in peak horizontal and vertical accelerations on the hanging wall over the distance range of 3 to 60km relative to the median attenuation for the Wenchuan earthquake.The peak acceleration residuals on the hanging wall appear to be biased to positive values whereas the residuals for footwall sites are negative.The EW component of horizontal accelerations is larger than the NS component and attenuates more slowly.(2) There is a lack of long period component in near-fault ground motion of Wenchuan earthquake,the value of spectrum acceleration decrease rapidly in the long period range.The maximum spectrum acceleration is only 0.5g even at locations very close to the main causative fault at period 1.0 s. Large distinctions are shown in the distribution of acceleration spectrum ratio (Vertical/ Horizontal) for near-source ground motion at longer periods (T=0.2 s,0.5 s,1.0 s) with respect to short periods (T=0.05 s,0.1 s).(3) High intensity of UD component is shown for near-fault ground motion,the PGA ratio (Vertical/Horizontal) can be as large as 1.4.High intensity of UD component is more obvious on the hanging wall,and the PGA ratios on the hanging wall are much larger compared with the footwall.For some near-fault records,the acceleration spectrum ratio (Vertical/Horizontal) can even be larger than 1.5.It can also be concluded that the acceleration spectrum ratio decrease with the increasing of fault distance at short periods (<0.1 s).
引文
[1] 卢寿德,李小军,杜玮等.汶川8． 0级地震未校正加速度记录.北京:地震出版社,2008 Lu S D,Li X J,Du W,et al.Report on Strong Motion Records in China.(in Chinese),Beijing:Seismological Press,2008
[2] 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.震灾防御技术,2008,3(4) :321～336 Yu H Y,Wang D,Yang Y Q,et al.The preliminary analysis of strong ground motion characteristics from the M_s 8． 0 Wenchuan earthquake.Technology for Earthquake Disaster Prevention(in Chinese),2008,3(4) :321～336
[3] Li X J,Zhou Z H,Yu H Y et al.Strong motion observations and recordings from the great Wenchuan Earthquake.Earthquake Engineering and Engineering Vibration,2008,7(3) :235～246
[4] 周锡元,徐平,王国权等.1999年台湾集集近断层竖向与水平反应谱比值的研究.地震地质,2006,28(3) :325～335 Zhou X Y,Xu P,Wang G Q,et al.A case study on nearfault vertical to horizontal response spectral ratio from the 1999 Chi-Chi earthquake.Seismology and Geology(in Chinese),2006,28(3) :325～335
[5] 周正华,周雍年,卢滔等.竖向地震动特征研究.地震工程与工程振动,2003,23(3) :25～29 Zhou Z H,Zhou Y N,Lu T,et al.Study on characteristics of vertical ground motion.Earthquake Engineering and Engineering Vibration(in Chinese),2003,23(3) :25～29
[6] Niazi M,Bozorgnia Y.Behavior of near source peak vertical and horizontal ground motion over SMART-1 array,Taiwan.Bulletin of Seismological Society of America,1991,81:715～732
[7] Niazi M,Bozorgnia Y.Behavior of Near Source Vertical and Horizontal Response Spectra at Smart-1 Array,Taiwan.Earthquake Engineering and Structural Dynamics,1992,21:37～50
[8] Bozorgnia Y,Niazi M.Distance scaling of vertical and horizontal response spectra of the Loma Prieta earthquake.Earthquake Engineering and Structural Dynamics,1993,22:695～707
[9] Bozorgnia Y,Niazi M,Campbell K W.Characteristics of free-field vertical ground motion in the 1994 Northridge earthquake.Earthquake Spectra,1995,11(4) :515～525
[10] Borzorgnia Y,Mahin S A,Brady A G.Vertical response of twelve structures recorded during the Northridge earthquake.Earthquake Spectra,1998,14(3) :411～432
[11] Watabe M,Tohdo M,Chiba O,Fukuzawa,R.Peak accelerations and response spectra of vertical strong motions from near-field record in USA.8 th Japan earthquake engineering Symposium.Proceedings,1990,1:301-306
[12] Abrahamson N A,Silva W J.Empirical response spectral attenuation relations for shallow crustal earthquakes.Seismological Research Letters,1997,68(1) :94～127
[13] Bozorgnia Y,Campbell K W.The vertical to horizontal response spectral ratio and tentative procedures for developing simplified V/H vertical design spectra.Journal of Earthquake Engineering,2004,8(2) :175～207
[14] Campbell K W,Bozorgnia Y.Updated near-source ground motion attenuation relations for the horizontal and vertical components of peak ground acceleration and acceleration response spectra.Bulletin of Seismological Society of America,2003,93(1) :314～331
[15] 徐锡伟,闻学泽,于慎鄂等.汶川M_s8． 0地震地表破裂带及其发震构造.地震地质,2008,30(3) :597～627 Xu X W,Wen X Z,Yu S E,et al.The M_s8． 0 Wenchuan earthquake surface ruptures and its seismogenic structure.Seismology and Geology(in Chinese),2008,30(3) :597～627
[16] Zhang Y,Feng W P,Xu L S,et al.Spatial-temporal rupture process of the 2008 great Wenchuan earthquake.Sci China Ser D-Earth Sci,2009,52(2) :145～154
[17] Wang W M,Zhao L F,Li J,et al.Rupture process of the M_s8． 0 Wenchuan earthquake of Sichuan,China.Chinese Journal of Geophysics(English Edition),2008,51(5) :1403～1010
[18] Du H L,Xu L S,Chen Y T.Rupture process of the 2008 great Wenchuan earthquake from the analysis of the Alaskaarray data.Chinese Journal of Geophysics(English Edition),2009,52(2) :372～378
[19] Koketsu K,Hikima K,Miyake H,Maruyama T.The source process and strong ground motions of the 2008 Sichuan,China,Earthquake.Proc.14th World Conf.on Earthquake Engineering,2008,Beijing,China
[20] Parsons T,Chen J,Kirby E.Stress changes from the 2008 Wenchuan earthquake and increased hazard in the Sichuan basin.Nature,2008,454:509～510
[21] Yu Y X,Gao M T.Effects of the hanging wall and footwall on peak acceleration during the Chi-Chi earthquake,Taiwan.Acta Seismologica Sinica(English Edition),2001,14(6) :654～659
[22] Abrahamson N A,Somerville P G.Effects of the hanging wall and footwall on Ground Motions Recorded during the Northridge Earthquake.Bulletin of Seismological Society of America,1996,86(1) :93～99
[2] 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.震灾防御技术,2008,3(4) :321～336 Yu H Y,Wang D,Yang Y Q,et al.The preliminary analysis of strong ground motion characteristics from the M_s 8． 0 Wenchuan earthquake.Technology for Earthquake Disaster Prevention(in Chinese),2008,3(4) :321～336
[3] Li X J,Zhou Z H,Yu H Y et al.Strong motion observations and recordings from the great Wenchuan Earthquake.Earthquake Engineering and Engineering Vibration,2008,7(3) :235～246
[4] 周锡元,徐平,王国权等.1999年台湾集集近断层竖向与水平反应谱比值的研究.地震地质,2006,28(3) :325～335 Zhou X Y,Xu P,Wang G Q,et al.A case study on nearfault vertical to horizontal response spectral ratio from the 1999 Chi-Chi earthquake.Seismology and Geology(in Chinese),2006,28(3) :325～335
[5] 周正华,周雍年,卢滔等.竖向地震动特征研究.地震工程与工程振动,2003,23(3) :25～29 Zhou Z H,Zhou Y N,Lu T,et al.Study on characteristics of vertical ground motion.Earthquake Engineering and Engineering Vibration(in Chinese),2003,23(3) :25～29
[6] Niazi M,Bozorgnia Y.Behavior of near source peak vertical and horizontal ground motion over SMART-1 array,Taiwan.Bulletin of Seismological Society of America,1991,81:715～732
[7] Niazi M,Bozorgnia Y.Behavior of Near Source Vertical and Horizontal Response Spectra at Smart-1 Array,Taiwan.Earthquake Engineering and Structural Dynamics,1992,21:37～50
[8] Bozorgnia Y,Niazi M.Distance scaling of vertical and horizontal response spectra of the Loma Prieta earthquake.Earthquake Engineering and Structural Dynamics,1993,22:695～707
[9] Bozorgnia Y,Niazi M,Campbell K W.Characteristics of free-field vertical ground motion in the 1994 Northridge earthquake.Earthquake Spectra,1995,11(4) :515～525
[10] Borzorgnia Y,Mahin S A,Brady A G.Vertical response of twelve structures recorded during the Northridge earthquake.Earthquake Spectra,1998,14(3) :411～432
[11] Watabe M,Tohdo M,Chiba O,Fukuzawa,R.Peak accelerations and response spectra of vertical strong motions from near-field record in USA.8 th Japan earthquake engineering Symposium.Proceedings,1990,1:301-306
[12] Abrahamson N A,Silva W J.Empirical response spectral attenuation relations for shallow crustal earthquakes.Seismological Research Letters,1997,68(1) :94～127
[13] Bozorgnia Y,Campbell K W.The vertical to horizontal response spectral ratio and tentative procedures for developing simplified V/H vertical design spectra.Journal of Earthquake Engineering,2004,8(2) :175～207
[14] Campbell K W,Bozorgnia Y.Updated near-source ground motion attenuation relations for the horizontal and vertical components of peak ground acceleration and acceleration response spectra.Bulletin of Seismological Society of America,2003,93(1) :314～331
[15] 徐锡伟,闻学泽,于慎鄂等.汶川M_s8． 0地震地表破裂带及其发震构造.地震地质,2008,30(3) :597～627 Xu X W,Wen X Z,Yu S E,et al.The M_s8． 0 Wenchuan earthquake surface ruptures and its seismogenic structure.Seismology and Geology(in Chinese),2008,30(3) :597～627
[16] Zhang Y,Feng W P,Xu L S,et al.Spatial-temporal rupture process of the 2008 great Wenchuan earthquake.Sci China Ser D-Earth Sci,2009,52(2) :145～154
[17] Wang W M,Zhao L F,Li J,et al.Rupture process of the M_s8． 0 Wenchuan earthquake of Sichuan,China.Chinese Journal of Geophysics(English Edition),2008,51(5) :1403～1010
[18] Du H L,Xu L S,Chen Y T.Rupture process of the 2008 great Wenchuan earthquake from the analysis of the Alaskaarray data.Chinese Journal of Geophysics(English Edition),2009,52(2) :372～378
[19] Koketsu K,Hikima K,Miyake H,Maruyama T.The source process and strong ground motions of the 2008 Sichuan,China,Earthquake.Proc.14th World Conf.on Earthquake Engineering,2008,Beijing,China
[20] Parsons T,Chen J,Kirby E.Stress changes from the 2008 Wenchuan earthquake and increased hazard in the Sichuan basin.Nature,2008,454:509～510
[21] Yu Y X,Gao M T.Effects of the hanging wall and footwall on peak acceleration during the Chi-Chi earthquake,Taiwan.Acta Seismologica Sinica(English Edition),2001,14(6) :654～659
[22] Abrahamson N A,Somerville P G.Effects of the hanging wall and footwall on Ground Motions Recorded during the Northridge Earthquake.Bulletin of Seismological Society of America,1996,86(1) :93～99
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