基于混合方法的南海海域地震动衰减关系研究
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摘要
我国南海海域面临俯冲带地震的影响,海域俯冲带地震的工程特性是海域工程抗震研究的基础,为给海域工程地震危险性分析提供合理的地震动输入,对于没有实际地震动数据的我国南海海域,文中提出一种基于数值模拟结合其他区域已有经验衰减关系建立本地衰减关系的方法。该方法采用随机有限断层法分别对南海俯冲带和日本东北部俯冲带板内地震动进行模拟,以模拟的不同震级、不同距离下的大量地震动为基础,回归了日本俯冲带与南海俯冲带地震动衰减关系,并推导二者的定量关系,基于此定量关系和已知的日本东北部俯冲带板内地震的经验衰减关系,最终建立南海俯冲带板内地震动的衰减关系。将文中建立的南海地震衰减关系与日本以及汶川地震衰减关系进行对比,结果表明:不同类型的地震的衰减特征存在一定的差异性,海域俯冲带板内地震的衰减速率要快于我国陆地地区的汶川地震的浅地壳地震;数值模拟结合经验关系的混合方法得到的南海俯冲带板内地震动衰减关系具有一定的应用价值,此方法可为没有实际地震动的地区建立衰减关系提供参考,建立的衰减关系可为海洋工程和近海交通重大工程的建设提供依据。
The South China Sea is located close to the subduction zone, and the engineering characteristics of subduction zone earthquakes is the basis of sea area seismic research. In order to supply reasonable ground motions for hazard analysis of offshore engineering, for the South China Sea without actual seismic data available, a method of establishing the local attenuation relationship was proposed based on the numerical simulations and the empirical attenuation relationships from other regions. In this method, the stochastic finite fault method was employed to simulate the ground motions of intraplate earthquakes for subduction zones of the South China Sea and the northeastern Japan. Based on these simulated ground motions of different magnitudes and epicentral distances, the ground motion attenuation relationships for these subduction zones were regressed. Hence, the quantitative relationship of the two subduction zones were obtained, and based on the quantitative relationship and the empirical attenuation relationship of Japan subduction zone, the earthquake attenuation relationship of intraplate earthquakes for the subduction zones of the South China Sea was eventually established. By comparing the attenuation relationship proposed in this work with those for Japan and Wenchuan earthquake, it is found that: the attenuation characteristics of different earthquakes have regional differences; the ground motion attenuation rate of the intraplate earthquakes for the subduction zones of sea is faster than that of the shallow crustal case such as the Wenchuan earthquake; the attenuation relationship for intraplate earthquake of the subduction zones established by the hybrid method of numerical simulation and empirical attenuation relationship, shall be applicable and can be referred by those regions without actual ground motions. Therefore, the established earthquake attenuation relationships can be referred by marine and offshore engineerings.
The South China Sea is located close to the subduction zone, and the engineering characteristics of subduction zone earthquakes is the basis of sea area seismic research. In order to supply reasonable ground motions for hazard analysis of offshore engineering, for the South China Sea without actual seismic data available, a method of establishing the local attenuation relationship was proposed based on the numerical simulations and the empirical attenuation relationships from other regions. In this method, the stochastic finite fault method was employed to simulate the ground motions of intraplate earthquakes for subduction zones of the South China Sea and the northeastern Japan. Based on these simulated ground motions of different magnitudes and epicentral distances, the ground motion attenuation relationships for these subduction zones were regressed. Hence, the quantitative relationship of the two subduction zones were obtained, and based on the quantitative relationship and the empirical attenuation relationship of Japan subduction zone, the earthquake attenuation relationship of intraplate earthquakes for the subduction zones of the South China Sea was eventually established. By comparing the attenuation relationship proposed in this work with those for Japan and Wenchuan earthquake, it is found that: the attenuation characteristics of different earthquakes have regional differences; the ground motion attenuation rate of the intraplate earthquakes for the subduction zones of sea is faster than that of the shallow crustal case such as the Wenchuan earthquake; the attenuation relationship for intraplate earthquake of the subduction zones established by the hybrid method of numerical simulation and empirical attenuation relationship, shall be applicable and can be referred by those regions without actual ground motions. Therefore, the established earthquake attenuation relationships can be referred by marine and offshore engineerings.
引文
[1]尚继宏,李家彪.南海东北部陆缘区新近纪早期反转构造特征及其动力学意义[J].海洋学报,2009,31(3):73-83(Shang Jihong,Li Jiabiao.Inversion structure features and their dynamic significances in early Neogene strata at continental margin of the northeast South China Sea[J].Acta Oceanlolgica Sinica,2009,31(3):73-83(in Chinese))
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[4]Si H J,Midorikawa S.New attenuation relations for peak ground acceleration and velocity considering effects of fault type and site condition[C]//Proceedings of 12th World Conference Earthquake Engineering.Auckland:New Zealand Society for Earthquake Engineering,2000:0532
[5]Chang T Y,Cotton F,Angelier J.Seismic attenuation and peak ground acceleration in Taiwan[J].Bulletin of the Seismological Society of America,2001,91(5):1229-1246
[6]Atkinson G M,Boore D M.Empirical ground-motion relations for subduction-zone earthquakes and their application to Cascadia and other regions[J].Bulletin of the Seismological Society of America,2003,93(4):1703-1729
[7]Lin P S,Lee C T.Ground-motion attenuation relationships for subduction-zone earthquakes in northeastern Taiwan[J].Bulletin of the Seismological Society of America,2008,98(1):220-240
[8]Vacareanu R,Pavel F,Aldea A.On the selection of GMPEs for Vrancea subcrustal seismic source[J].Bulletin of Earthquake Engineering,2013,11(6):1867-1884
[9]Ghofrani H,Atkinson G M.Ground-motion prediction equations for interface earthquakes of M7 to M9 based on empirical data from Japan[J].Bulletin of Earthquake Engineering,2014,12(2):549-571
[10]Motazedian D,Atkinson G M.Stochastic finite-fault modeling based on a dynamic corner frequency[J].Bulletin of the Seismological Society of America,2005,95(3):995-1010
[11]王国新,史家平.随机有限断层法在汶川强地震动模拟中的应用[J].自然科学进展,2009,19(6):664-669
[12]Anderson J G,Hough S E.A model for the shape of the fourier amplitude spectrums of acceleration at high frequencies[J].Bulletin of the Seismological Society of America,1984,74(5):1969-1993
[13]Brune J N.Tectonic stress and the spectra of seismic shear waves from earthquakes[J].Journal of Geophysical Research,1970,75(26):4997-5009
[14]Wells D L,Coppersimth K J.New empirical relationships among magnitude,rupture length,rupture width,rupture area and surface displacement[J].Bulletin of the Seismological Society of America,1994,84(4):974-1002
[15]Beresnev I A,Atkinson G M.Modeling finite-fault radiation from the omega-n spectrum[J].Bulletin of the Seismological Society of America,1997,87(1):67-84
[16]Atkinson G M,Macias M.Predicted ground motions for great interface earthquakes in the Cascadia subduction zone[J].Bulletin of the Seismological Society of America,2009,99(3):1552-1578
[17]陈传绪,吴时国,赵昌垒.马尼拉海沟北段俯冲带输入板块的不均一性[J].地球物理学报,2014,57(12):4063-4073(Chen Chuanxu,Wu Shiguo,Zhao Changlei.Incoming plate variation along the northern Manila Trench[J].Chinese Journal of Geophysics,2014,57(12):4063-4073(in Chinese))
[18]陈志豪,李家彪,吴自银,等.马尼拉海沟几何形态特征的构造演化意义[J].海洋地质与第四纪地质,2009,29(2):59-65(Chen Zhihao,Li Jiabiao,Wu Ziyin,et al.Tectonic evolution implication of geometry shape characteristics for Manila Trench[J].Marine Geology and Quaternary Geology,2009,29(2):59-65(in Chinese))
[19]郝彦春.俯冲带地震动特性及衰减规律初步研究[D].哈尔滨:中国地震局工程力学研究所,2015(Hao Yanchun.The preliminary study on characteristics of subduction-zone ground motion and its attenuation relationship[D].Harbin:Institute of Engineering Mechanics,China Earthquake Administration,2015(in Chinese))
[20]闵慧,任建业,高金耀,等.南海北部古俯冲带的位置及其对南海扩张的控制[J].大地构造与成矿学,2010,34(4):599-605(Min Hui,Ren Jianye,Gao Jinyao,et al.Location of the ancient subduction zone in the northern South China Sea and its constrains on the spreading of the South China Sea basin[J].Geotectonica et Metallogenia,2010,34(4):599-605(in Chinese))
[21]薛友辰,李三忠,刘鑫,等.南海东部俯冲系统分段性及相关盆地群成盆动力学机制[J].海洋地质与第四纪地质,2012,32(6):129-147(Xue Youchen,Li Sanzhong,Liu Xin,et al.Segmentation of subduction system in the eastern south China sea and dynamics of related basin groups[J].Marine Geology and Quaternary Geology,2012,32(6):129-147(in Chinese))
[22]赵明辉,贺恩远,孙龙涛,等.马里亚纳海沟俯冲带深地震现状对马尼拉海沟俯冲带的研究启示[J].热带海洋学报,2016,35(1):48-60(Zhao Minghui,He Enyuan,Sun Longtao,et al.The research on deep seismic structures of Mariana trench subduction zone and its significance for Manila trench subduction zone[J].Journal of Tropical Oceanography,2016,35(1):48-60(in Chinese))
[23]Zhao J X,Zhang J,Asano A,et al.Attenuation relations of strong ground motion in Japan using site classification based on predominant period[J].Bulletin of the Seismological Society of America,2006,96(3):898-913
[24]王玉石,李小军,周正华.川滇地区水平向强地震动衰减关系研究[J].地震学报,35(2):238-249(Wang Yushi,Li Xiaojun,Zhou Zhenghua.Research on attenuation relationships for horizontal strong ground motions in Sichuan—Yunnan region[J].Acta Seismlolgica Sinica,35(2):238-249(in Chinese))
[2]Crouse C B,Vyas Y K,Schell B A.Ground motions from subduction-zone earthquakes[J].Bulletin of the Seismological Society of America,1988,78(1):1-25
[3]Youngs R R,Chiou S J,Silva W J,et al.Strong ground motion attenuation relationships for subduction zone earthquakes[J].Seismological Research Letters,1997,68(1):58-73
[4]Si H J,Midorikawa S.New attenuation relations for peak ground acceleration and velocity considering effects of fault type and site condition[C]//Proceedings of 12th World Conference Earthquake Engineering.Auckland:New Zealand Society for Earthquake Engineering,2000:0532
[5]Chang T Y,Cotton F,Angelier J.Seismic attenuation and peak ground acceleration in Taiwan[J].Bulletin of the Seismological Society of America,2001,91(5):1229-1246
[6]Atkinson G M,Boore D M.Empirical ground-motion relations for subduction-zone earthquakes and their application to Cascadia and other regions[J].Bulletin of the Seismological Society of America,2003,93(4):1703-1729
[7]Lin P S,Lee C T.Ground-motion attenuation relationships for subduction-zone earthquakes in northeastern Taiwan[J].Bulletin of the Seismological Society of America,2008,98(1):220-240
[8]Vacareanu R,Pavel F,Aldea A.On the selection of GMPEs for Vrancea subcrustal seismic source[J].Bulletin of Earthquake Engineering,2013,11(6):1867-1884
[9]Ghofrani H,Atkinson G M.Ground-motion prediction equations for interface earthquakes of M7 to M9 based on empirical data from Japan[J].Bulletin of Earthquake Engineering,2014,12(2):549-571
[10]Motazedian D,Atkinson G M.Stochastic finite-fault modeling based on a dynamic corner frequency[J].Bulletin of the Seismological Society of America,2005,95(3):995-1010
[11]王国新,史家平.随机有限断层法在汶川强地震动模拟中的应用[J].自然科学进展,2009,19(6):664-669
[12]Anderson J G,Hough S E.A model for the shape of the fourier amplitude spectrums of acceleration at high frequencies[J].Bulletin of the Seismological Society of America,1984,74(5):1969-1993
[13]Brune J N.Tectonic stress and the spectra of seismic shear waves from earthquakes[J].Journal of Geophysical Research,1970,75(26):4997-5009
[14]Wells D L,Coppersimth K J.New empirical relationships among magnitude,rupture length,rupture width,rupture area and surface displacement[J].Bulletin of the Seismological Society of America,1994,84(4):974-1002
[15]Beresnev I A,Atkinson G M.Modeling finite-fault radiation from the omega-n spectrum[J].Bulletin of the Seismological Society of America,1997,87(1):67-84
[16]Atkinson G M,Macias M.Predicted ground motions for great interface earthquakes in the Cascadia subduction zone[J].Bulletin of the Seismological Society of America,2009,99(3):1552-1578
[17]陈传绪,吴时国,赵昌垒.马尼拉海沟北段俯冲带输入板块的不均一性[J].地球物理学报,2014,57(12):4063-4073(Chen Chuanxu,Wu Shiguo,Zhao Changlei.Incoming plate variation along the northern Manila Trench[J].Chinese Journal of Geophysics,2014,57(12):4063-4073(in Chinese))
[18]陈志豪,李家彪,吴自银,等.马尼拉海沟几何形态特征的构造演化意义[J].海洋地质与第四纪地质,2009,29(2):59-65(Chen Zhihao,Li Jiabiao,Wu Ziyin,et al.Tectonic evolution implication of geometry shape characteristics for Manila Trench[J].Marine Geology and Quaternary Geology,2009,29(2):59-65(in Chinese))
[19]郝彦春.俯冲带地震动特性及衰减规律初步研究[D].哈尔滨:中国地震局工程力学研究所,2015(Hao Yanchun.The preliminary study on characteristics of subduction-zone ground motion and its attenuation relationship[D].Harbin:Institute of Engineering Mechanics,China Earthquake Administration,2015(in Chinese))
[20]闵慧,任建业,高金耀,等.南海北部古俯冲带的位置及其对南海扩张的控制[J].大地构造与成矿学,2010,34(4):599-605(Min Hui,Ren Jianye,Gao Jinyao,et al.Location of the ancient subduction zone in the northern South China Sea and its constrains on the spreading of the South China Sea basin[J].Geotectonica et Metallogenia,2010,34(4):599-605(in Chinese))
[21]薛友辰,李三忠,刘鑫,等.南海东部俯冲系统分段性及相关盆地群成盆动力学机制[J].海洋地质与第四纪地质,2012,32(6):129-147(Xue Youchen,Li Sanzhong,Liu Xin,et al.Segmentation of subduction system in the eastern south China sea and dynamics of related basin groups[J].Marine Geology and Quaternary Geology,2012,32(6):129-147(in Chinese))
[22]赵明辉,贺恩远,孙龙涛,等.马里亚纳海沟俯冲带深地震现状对马尼拉海沟俯冲带的研究启示[J].热带海洋学报,2016,35(1):48-60(Zhao Minghui,He Enyuan,Sun Longtao,et al.The research on deep seismic structures of Mariana trench subduction zone and its significance for Manila trench subduction zone[J].Journal of Tropical Oceanography,2016,35(1):48-60(in Chinese))
[23]Zhao J X,Zhang J,Asano A,et al.Attenuation relations of strong ground motion in Japan using site classification based on predominant period[J].Bulletin of the Seismological Society of America,2006,96(3):898-913
[24]王玉石,李小军,周正华.川滇地区水平向强地震动衰减关系研究[J].地震学报,35(2):238-249(Wang Yushi,Li Xiaojun,Zhou Zhenghua.Research on attenuation relationships for horizontal strong ground motions in Sichuan—Yunnan region[J].Acta Seismlolgica Sinica,35(2):238-249(in Chinese))