近断层地震时-频谱特性小波变换分析
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摘要
借助小波变换,研究汶川地震(Wen Chuan earthquake,2008)什邡八角台站加速度记录的局部谱密度分布特点.通过对小波分量的重构来解析加速度脉冲,发现地震能量富集于中、高频段内,在时域上存在显著的能量双峰,地震波长周期成分并不明显.对美国洛杉矶北岭地震(Northridge earthquake,1994)Sylmar-OliveView台站加速度记录进行研究,通过循环移位操作来分离低频加速度脉冲,发现低频加速度脉冲对长周期结构的破坏作用更显著.因此,借助小波方法研究近断层地震独具优势,可为相关领域的抗震研究提供新思路.
Through wavelet transform method,the local spectral density of acceleration records obtained from Shifang Bajiao station(Wenchuan earthquake,2008) are analyzed,and the acceleration pulse is parsed by wavelet vector reconstruction.It shows that seismic energy is gathered near high frequency band,and there is significant energy twin peaks in the time domain.Meanwhile,long-period components of the earthquake adjacent to the fault are not obvious.Acceleration record of Sylmar-Olive View station(Los Angeles Northridge earthquake,1994) is also studied,and low-frequency acceleration pulse is detached through the cyclic shift operation.It turns out that the low-frequency acceleration pulse is more destructive to the long-periodic structure.The wavelet method has great advantages of analyzing the near-fault ground motions,and it can provide new ideas in the related area of anti-seismic research.
Through wavelet transform method,the local spectral density of acceleration records obtained from Shifang Bajiao station(Wenchuan earthquake,2008) are analyzed,and the acceleration pulse is parsed by wavelet vector reconstruction.It shows that seismic energy is gathered near high frequency band,and there is significant energy twin peaks in the time domain.Meanwhile,long-period components of the earthquake adjacent to the fault are not obvious.Acceleration record of Sylmar-Olive View station(Los Angeles Northridge earthquake,1994) is also studied,and low-frequency acceleration pulse is detached through the cyclic shift operation.It turns out that the low-frequency acceleration pulse is more destructive to the long-periodic structure.The wavelet method has great advantages of analyzing the near-fault ground motions,and it can provide new ideas in the related area of anti-seismic research.
引文
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[3]谢俊举,温增平,李小军.基于小波方法分析汶川地震近断层地震动的速度脉冲特性[J].地球物理学报,2012,55(6):1 963-1 972.
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[7]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[J].震灾防御技术,2008,3(4):321-336.
[8]王锋,陈清军.断层附近的地震波频谱特性与结构动力反应分析[J].结构工程师,2011,27(5):102-110.
[9]Loh C H,Liao W I,Chai J F.Effect of near-fault earthquake on bridges:lessons learned from Chi-Chi earthquake[J].Earthquake Engineering and Engineering Vibration,2002,1(1):86-93.
[10]曹晖.近场地震动加速度脉冲的小波变换识别[J].重庆大学学报:自然科学版,2007,30(8):119-122.
[11]Zhu Bing,Xing Fan,Li Xiangjun.Dynamic performance of box girder and CFST arch combination bridge considering pile-soil interaction[C]//International Conference on Transportation Engineering ASCE,2009:1 371-1 377.
[12]高西全,丁玉美.数字信号:数字信号处理[M].3版.西安:西安电子科技大学出版社,2008.
[2]杨红,曹晖,白绍良.地震波局部时频特性对结构非线性响应的影响[J].土木工程学报,2001,34(4):78-82.
[3]谢俊举,温增平,李小军.基于小波方法分析汶川地震近断层地震动的速度脉冲特性[J].地球物理学报,2012,55(6):1 963-1 972.
[4]Basu B,Gupta V K.Non-stationary seismic response of MDOF systems by wavelet transform[J].Earthquake Engineering andStructural Dynamics,1997,26:1 243-1 258.
[5]任宜春,张杰峰,易伟建.基于改进L-P小波的时变模态参数识别方法[J].振动与冲击,2009,28(3):144-148.
[6]曹晖,赖明,白绍良.地震地面运动局部谱密度的小波变换估计[J].工程力学,2004,21(5):109-115.
[7]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[J].震灾防御技术,2008,3(4):321-336.
[8]王锋,陈清军.断层附近的地震波频谱特性与结构动力反应分析[J].结构工程师,2011,27(5):102-110.
[9]Loh C H,Liao W I,Chai J F.Effect of near-fault earthquake on bridges:lessons learned from Chi-Chi earthquake[J].Earthquake Engineering and Engineering Vibration,2002,1(1):86-93.
[10]曹晖.近场地震动加速度脉冲的小波变换识别[J].重庆大学学报:自然科学版,2007,30(8):119-122.
[11]Zhu Bing,Xing Fan,Li Xiangjun.Dynamic performance of box girder and CFST arch combination bridge considering pile-soil interaction[C]//International Conference on Transportation Engineering ASCE,2009:1 371-1 377.
[12]高西全,丁玉美.数字信号:数字信号处理[M].3版.西安:西安电子科技大学出版社,2008.
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