采用随机有限断层法生成最大可信地震
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摘要
本文依据基于地震学理论合成地震动的随机方法和能够细致描述震源复杂性的有限断层模型,采用随机有限断层法直接生成最大可信地震。重点比较了随机有限断层法的静拐角频率和动拐角频率理论,开发基于静拐角频率方法的Fortran程序SFFMSIM,作为对比,引进了动拐角频率程序EXSIM。选用1994年Northridge地震数据检验本文采用的随机有限断层模拟方法和程序。最后以大岗山水电站工程为例,采用随机有限断层法生成磨西断裂发震时工程场址可能产生的最大可信地震的加速度时程曲线。结果显示:随机有限断层法合成时程的放大系数谱均值与80条基岩记录平均谱的一致性较好。预测震源位错分布形式未知的地震时,动拐角频率和静拐角频率方法的模拟结果有差异。
On account of the stochastic method of ground motion simulation based on seismology theory and the finite fault source model which can describe the complexity of the earthquake source accurately,the stochastic finite fault method is applied directly to generate the maximum credible earthquake.Two theories of the stochastic finite fault method,including the static corner frequency theory and dynamic corner frequency theory,are compared.According to the static corner frequency theory,a Fortran program SFFMSIM is developed,while EXSIM,a program based on the dynamic corner frequency theory,is introduced for comparison.The stochastic finite fault method and procedures of simulating ground motions used in this paper are validated against strong motion data of 1994 Northridge earthquake.Finally,taking the Dagangshan hydropower for example,the artificial accelerograms of the maximum credible earthquake generated from the rupture of Moxi fault and recorded at the dam site are simulated by the stochastic finite fault method.The results show that the average values of the strong-motion amplification factors produced by the stochastic finite fault method and those derived from 80 real rock accelerograms are in good agreement.There are some differences between strong motions simulated by the static corner frequency method and dynamic corner frequency method when the slip distribution on the causative fault is unknown.
On account of the stochastic method of ground motion simulation based on seismology theory and the finite fault source model which can describe the complexity of the earthquake source accurately,the stochastic finite fault method is applied directly to generate the maximum credible earthquake.Two theories of the stochastic finite fault method,including the static corner frequency theory and dynamic corner frequency theory,are compared.According to the static corner frequency theory,a Fortran program SFFMSIM is developed,while EXSIM,a program based on the dynamic corner frequency theory,is introduced for comparison.The stochastic finite fault method and procedures of simulating ground motions used in this paper are validated against strong motion data of 1994 Northridge earthquake.Finally,taking the Dagangshan hydropower for example,the artificial accelerograms of the maximum credible earthquake generated from the rupture of Moxi fault and recorded at the dam site are simulated by the stochastic finite fault method.The results show that the average values of the strong-motion amplification factors produced by the stochastic finite fault method and those derived from 80 real rock accelerograms are in good agreement.There are some differences between strong motions simulated by the static corner frequency method and dynamic corner frequency method when the slip distribution on the causative fault is unknown.
引文
[1]陈厚群,徐泽平,李敏.汶川大地震和大坝抗震安全[J].水利学报,2008,39(10):1158-1167.
[2]Boore D M.Simulation of ground motion using the stochastic method[J].Pure and Applied Geophysics,2003,160:635-676.
[3]Beresnev I A,Atkinson G M.Stochastic finite-fault modeling of ground motions from the1994Northridge,Cali fornia,earthquake,I.Validation on rock sites[J].Bulletin of the Seismological Society of America,1998,88(6):1392-1401.
[4]Beresnev I A,Atkinson G M.Generic finite fault model for ground motion prediction in eastern North America[J].Bulletin of the Seismological Society of America,1999,89(3):608-625.
[5]Beresnev I A,Atkinson G M.Modeling finite-fault radiation from the w nspectrum[J].Bulletin of the Seismologi cal Society of America,1997,87(1):67-84.
[6]Beresnev I A,Atkinson G M.Source parameters of earthquakes in eastern and western north America based on fi nite-fault modeling[J].Bulletin of the Seismological Society of America,2002,92(2):695-710.
[7]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.
[8]王海云,陶夏新.近场强地震动预测中浅源地震的Asperity模型特征[J].哈尔滨工业大学学报,2005,37(11):1534-1539.
[9]王国新.强地震动衰减研究[D].哈尔滨:中国地震局工程力学研究所,2001.
[10]Wald D J,Heaton T H,Hudnut K W.The slip history of the1994Northridge,California,earthquake deter mined from strong-motion,teleseismic,GPS,and leveling data[J].Bulletin of the Seismological Society of America,1996,86:S49-S70.
[11]Wells D L,Coppersmith K J.New empirical relationships among magnitude,rupture length,rupture width,rup ture area,and surface displacement[J].Bulletin of the Seismological Society of America,1994,84(4):974-1002.
[12]Hanks T C,Kanamori H.A moment magnitude scale[J].Journal of Geophysical Research,1979,84(B5):2348-2350.
[13]石玉成.基于设定地震的重大水利水电工程抗震设防研究[D].北京:中国水利水电科学研究院,2006.
[14]SL203-97.水工建筑物抗震设计规范[S].北京:中华人民共和国水利部,1997.
[15]DL5073-2000.水工建筑物抗震设计规范[S].北京:中华人民共和国国家经济贸易委员会,2000.
[2]Boore D M.Simulation of ground motion using the stochastic method[J].Pure and Applied Geophysics,2003,160:635-676.
[3]Beresnev I A,Atkinson G M.Stochastic finite-fault modeling of ground motions from the1994Northridge,Cali fornia,earthquake,I.Validation on rock sites[J].Bulletin of the Seismological Society of America,1998,88(6):1392-1401.
[4]Beresnev I A,Atkinson G M.Generic finite fault model for ground motion prediction in eastern North America[J].Bulletin of the Seismological Society of America,1999,89(3):608-625.
[5]Beresnev I A,Atkinson G M.Modeling finite-fault radiation from the w nspectrum[J].Bulletin of the Seismologi cal Society of America,1997,87(1):67-84.
[6]Beresnev I A,Atkinson G M.Source parameters of earthquakes in eastern and western north America based on fi nite-fault modeling[J].Bulletin of the Seismological Society of America,2002,92(2):695-710.
[7]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.
[8]王海云,陶夏新.近场强地震动预测中浅源地震的Asperity模型特征[J].哈尔滨工业大学学报,2005,37(11):1534-1539.
[9]王国新.强地震动衰减研究[D].哈尔滨:中国地震局工程力学研究所,2001.
[10]Wald D J,Heaton T H,Hudnut K W.The slip history of the1994Northridge,California,earthquake deter mined from strong-motion,teleseismic,GPS,and leveling data[J].Bulletin of the Seismological Society of America,1996,86:S49-S70.
[11]Wells D L,Coppersmith K J.New empirical relationships among magnitude,rupture length,rupture width,rup ture area,and surface displacement[J].Bulletin of the Seismological Society of America,1994,84(4):974-1002.
[12]Hanks T C,Kanamori H.A moment magnitude scale[J].Journal of Geophysical Research,1979,84(B5):2348-2350.
[13]石玉成.基于设定地震的重大水利水电工程抗震设防研究[D].北京:中国水利水电科学研究院,2006.
[14]SL203-97.水工建筑物抗震设计规范[S].北京:中华人民共和国水利部,1997.
[15]DL5073-2000.水工建筑物抗震设计规范[S].北京:中华人民共和国国家经济贸易委员会,2000.
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