扬州4.9级地震破裂参数与强震动的经验估计
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摘要
2012年7月20日20时11分,江苏省扬州市高邮、宝应交界处发生了4.9级地震,震源深度5km,为1990年2月10日常熟5.1级地震以来江苏省发生的最大地震。为了定量和定性地分析本次地震特征,首先利用经验关系估算了其破裂面的长、宽和面积,以及破裂上升时间、滑动量和应力降等参数;然后基于我国东部PGA和烈度衰减关系对地震动强度进行了估算,并就其分布特征、彼此的差异及其影响因素进行了讨论;最后结合2002年5月13日美国Gilroy 4.9级地震的强震动记录,分析了强震动峰值的衰减和离散性、特征周期随断层距的变化特征,探讨了场地条件对强震动可能造成的影响。
On July 20,2012,M4.9 earthquake occurred near the boundary of Gaoyou and Baoying,Jiangsu Province.The focal depth is about 5 km.It is the biggest earthquake in Jiangsu since 1990.To study the earthquake qualitatively and quantificationally,empirical relationships are employed to estimate the length,width and area of the rupture plane,and related rise time,slippage and stress drop.Then,the seismic intensities based on empirical PGA and intensity attenuation relationships are computed respectively.The distribution characteristics and the difference between the results are analyzed,and potential influence factors are discussed.At last,the strong motion records from M4.9 Gilroy earthquake are used to describe the possible variability of PGA and response spectrum.The effect of site condition is discussed.The results could provide a better understanding of Yangzhou earthquake,for its shortage of strong motion records.
On July 20,2012,M4.9 earthquake occurred near the boundary of Gaoyou and Baoying,Jiangsu Province.The focal depth is about 5 km.It is the biggest earthquake in Jiangsu since 1990.To study the earthquake qualitatively and quantificationally,empirical relationships are employed to estimate the length,width and area of the rupture plane,and related rise time,slippage and stress drop.Then,the seismic intensities based on empirical PGA and intensity attenuation relationships are computed respectively.The distribution characteristics and the difference between the results are analyzed,and potential influence factors are discussed.At last,the strong motion records from M4.9 Gilroy earthquake are used to describe the possible variability of PGA and response spectrum.The effect of site condition is discussed.The results could provide a better understanding of Yangzhou earthquake,for its shortage of strong motion records.
引文
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[7]Someville P,Irikura K,Graves R,et al.Characteri-zing crustal earthquake slip models for the prediction ofstrong ground motion[J].Seismological Research Let-ters,1999,70(1):59-80.
[8]Mohammadioun B,Serva L.Stress drop,slip type,earthquake magnitude,and seismic hazard[J].Bulletinof the Seismological Society of America,2001,91(4):694-707.
[9]俞言祥,汪素云.中国东部和西部地区水平向基岩加速度反应谱衰减关系[J].震灾防御技术,2006,1(3):206-217.Yu Y X,Wang S Y.Attenuation relations for horizon-tal peak ground acceleration and response spectrum ineastern and western China[J].Technology of Earth-quake Disaster Prevention,2006,1(3):206-217.
[10]GB/T17742-2008,中国地震烈度表[S].
[11]汪素云,俞言祥,高阿甲,等.中国分区地震动衰减关系的确定[J].中国地震,2000,16(2):99-106.Wang S Y,Yu Y X,Gao A J,et al.Development ofattenuation relations for ground motion in China[J].Earthquake Research in China,2000,16(2):99-106.
[12]USGS.Magnitude 4.9near Gilroy,CA[EB/OL].ht-tp://earthquake.usgs.gov/earthquakes/eqinthenews/2002/nc40133364/[EB/OL].2012-08-09.
[13]PEER.Pacific Earthquake Engineering Research Cen-ter:NGA Database[EB/OL].http://peer.berkeley.edu/nga/,2012-08-09.
[2]Wells D L,Coppersmith K J.New empirical relation-ships among magnitude,rupture length,rupturewidth,rupture area,and surface displacement[J].Bulletin of the Seismological Society of America,1994,84(4):974-1002.
[3]胡聿贤.地震工程学(第二版)[M].北京:地震出版社,2006.Hu Y X.Earthquake Engineering(2nd Editin)[M].Beijing:Seismological Press,2006.
[4]Kanamori H.Magnitude scale and quantification of earth-quakes[J].Tectonophysics,1983,93(3):185-199.
[5]Boore D M,Joyner W B.The empirical predication ofground motion[J].Bulletin of the Seismological Socie-ty of America,1982,72(6):43-60.
[6]Geller R J.Scaling relations for earthquake source pa-rameters and magnitudes[J].Bulletin of the Seismo-logical Society of America,1976,66(5):1501-1523.
[7]Someville P,Irikura K,Graves R,et al.Characteri-zing crustal earthquake slip models for the prediction ofstrong ground motion[J].Seismological Research Let-ters,1999,70(1):59-80.
[8]Mohammadioun B,Serva L.Stress drop,slip type,earthquake magnitude,and seismic hazard[J].Bulletinof the Seismological Society of America,2001,91(4):694-707.
[9]俞言祥,汪素云.中国东部和西部地区水平向基岩加速度反应谱衰减关系[J].震灾防御技术,2006,1(3):206-217.Yu Y X,Wang S Y.Attenuation relations for horizon-tal peak ground acceleration and response spectrum ineastern and western China[J].Technology of Earth-quake Disaster Prevention,2006,1(3):206-217.
[10]GB/T17742-2008,中国地震烈度表[S].
[11]汪素云,俞言祥,高阿甲,等.中国分区地震动衰减关系的确定[J].中国地震,2000,16(2):99-106.Wang S Y,Yu Y X,Gao A J,et al.Development ofattenuation relations for ground motion in China[J].Earthquake Research in China,2000,16(2):99-106.
[12]USGS.Magnitude 4.9near Gilroy,CA[EB/OL].ht-tp://earthquake.usgs.gov/earthquakes/eqinthenews/2002/nc40133364/[EB/OL].2012-08-09.
[13]PEER.Pacific Earthquake Engineering Research Cen-ter:NGA Database[EB/OL].http://peer.berkeley.edu/nga/,2012-08-09.
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