矩形和钟形震源时间函数对地震动模拟结果的影响比较
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摘要
首先介绍了用于地震动数值模拟的国际通用软件COMPSYN程序,并对此进行了二次开发,将其震源时间函数由矩形函数改为钟形函数,通过与全空间的解析解计算结果的对比,验证了修改后程序的正确性。通过对比2种震源时间函数的频谱特点,指出矩形函数的高频成分丰富,不利于地震动的模拟。2种震源时间函数下用COMPSYN程序对同一观测点地震动模拟的结果表明,矩形函数模拟的时程出现"振铃"和"锯齿"现象,且随截止频率的增加而加重,影响了对模拟地震图的识别,而钟形函数模拟的时程较为平滑,说明采用钟形函数进行地震动数值模拟是比较合理的。
This paper firstly introduces the worldwide-used COMPSYN software into the numerical simulation of seismic motions,and then makes a second exploitation of it with boxcar source time function replaced by bell function.Validity of modified code is confirmed by comparing it with analytical method in total space.By the comparison between spectrum characteristics of boxcar and bell function,it is pointed out that the boxcar function is rich in high frequencies,which goes against the seismic motion simulation.For the same observation,the seismic simulation results from COMPSYN code with two different source time functions show that the time-history simulated by boxcar function is featured by "ringing" and "serrate" phenomena,and it becomes worse as cut-off frequency grows,which affects the recognition of simulated seismogram,while the time-history simulated by bell function is quite smooth,which explains the rationality of bell function used in seismic motion simulation.
This paper firstly introduces the worldwide-used COMPSYN software into the numerical simulation of seismic motions,and then makes a second exploitation of it with boxcar source time function replaced by bell function.Validity of modified code is confirmed by comparing it with analytical method in total space.By the comparison between spectrum characteristics of boxcar and bell function,it is pointed out that the boxcar function is rich in high frequencies,which goes against the seismic motion simulation.For the same observation,the seismic simulation results from COMPSYN code with two different source time functions show that the time-history simulated by boxcar function is featured by "ringing" and "serrate" phenomena,and it becomes worse as cut-off frequency grows,which affects the recognition of simulated seismogram,while the time-history simulated by bell function is quite smooth,which explains the rationality of bell function used in seismic motion simulation.
引文
[1]Olson A H,Orcutt J A,Frazier G A.The discrete wavenumber/finite element method for synthetic seismograms[J].Geophysical Journal of theAstronomical Society,1984,(77):421-460.
[2]Alterman Z,Karal F C.Propagation of elastic waves in layered media by finite difference methods[J].Bulletin of the Seismological Society of America,1968,58(1):367-398.
[3]Bolt B A.地震强地面运动合成[M].北京:地震出版社,1990.139-178.Bolt B A.Seismic Strong Motion Synthetics[M].Beijing:Seismological Press,1990.139-178.
[4]许力生,陈运泰.震源时间函数与震源破裂过程[J].地震地磁观测与研究,2002,23(6):1-7.Xu L S,Chen Y T.Source time function and rupture process of earthquake[J].Seismological and Geomagnetic Observation and Research,2002,23(6):1-7.
[5]安艺敬一,理查兹.定量地震学[M].北京:地震出版社,1986.Aki K,Richards P G.Quantitative Seismology Theory and Methods[M].Beijing:Seismological Press,1986.
[6]刘启方.基于运动学和动力学震源模型的近断层地震动研究[D].哈尔滨:中国地震局工程力学研究所,2005.Liu Q F.Studies on near-fault ground motions based on kinematic and dynamic source models[D].Harbin:Institute of Engineering Mechanics of China Earthquake Administration,2005.
[7]邵玉平,韩进,杨晓源,等.用于地震观测的瞬态滤波器仿真研究[J].地震地磁观测与研究,2009,30(3):90-93.Shao Y P,Han J,Yang X Y,et al.The simulation study of instantaneous filter applied for earthquake observation[J].Seismological and Geomagnetic Observation and Research,2009,30(3):90-93.
[2]Alterman Z,Karal F C.Propagation of elastic waves in layered media by finite difference methods[J].Bulletin of the Seismological Society of America,1968,58(1):367-398.
[3]Bolt B A.地震强地面运动合成[M].北京:地震出版社,1990.139-178.Bolt B A.Seismic Strong Motion Synthetics[M].Beijing:Seismological Press,1990.139-178.
[4]许力生,陈运泰.震源时间函数与震源破裂过程[J].地震地磁观测与研究,2002,23(6):1-7.Xu L S,Chen Y T.Source time function and rupture process of earthquake[J].Seismological and Geomagnetic Observation and Research,2002,23(6):1-7.
[5]安艺敬一,理查兹.定量地震学[M].北京:地震出版社,1986.Aki K,Richards P G.Quantitative Seismology Theory and Methods[M].Beijing:Seismological Press,1986.
[6]刘启方.基于运动学和动力学震源模型的近断层地震动研究[D].哈尔滨:中国地震局工程力学研究所,2005.Liu Q F.Studies on near-fault ground motions based on kinematic and dynamic source models[D].Harbin:Institute of Engineering Mechanics of China Earthquake Administration,2005.
[7]邵玉平,韩进,杨晓源,等.用于地震观测的瞬态滤波器仿真研究[J].地震地磁观测与研究,2009,30(3):90-93.Shao Y P,Han J,Yang X Y,et al.The simulation study of instantaneous filter applied for earthquake observation[J].Seismological and Geomagnetic Observation and Research,2009,30(3):90-93.
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