丁海平, 罗翼, 饶威波, 朱越. 2018: 截止频率的取值对地震动空间相干函数统计结果的影响. 地震学报, 40(5): 664-672. DOI: 10.11939/jass.20170185
引用本文: 丁海平, 罗翼, 饶威波, 朱越. 2018: 截止频率的取值对地震动空间相干函数统计结果的影响. 地震学报, 40(5): 664-672. DOI: 10.11939/jass.20170185
Ding Haiping, Luo Yi, Rao Weibo, Zhu Yue. 2018: The influence of cut-off frequency on the statistical results of spatial coherency function of seismic ground motion. Acta Seismologica Sinica, 40(5): 664-672. DOI: 10.11939/jass.20170185
Citation: Ding Haiping, Luo Yi, Rao Weibo, Zhu Yue. 2018: The influence of cut-off frequency on the statistical results of spatial coherency function of seismic ground motion. Acta Seismologica Sinica, 40(5): 664-672. DOI: 10.11939/jass.20170185

截止频率的取值对地震动空间相干函数统计结果的影响

The influence of cut-off frequency on the statistical results of spatial coherency function of seismic ground motion

  • 摘要: 以SMART-1台阵第45号地震的南北分量加速度作为研究对象,计算截止频率fcut分别为8,16和24 Hz,台站间距分别为200,1 000和2 000 m这9种工况的相干系数,并进行曲线拟合,再根据9组拟合参数计算相应的相干系数并进行比较。结果表明:① 截止频率fcut的取值对相干函数统计模型参数和相干系数拟合曲线有很大影响;② 根据较小的截止频率fcut得到的拟合参数计算出的相干系数随频率的衰减很快,反之,根据较大的截止频率fcut得到的拟合参数计算出的相干系数随频率的衰减较慢;③ 当使用由确定的截止频率fcut得到的相干系数拟合参数计算超出截止频率fcut范围的相干系数时,将产生很大的误差。

     

    Abstract: Based on the north-south component of the 45th seismic record on the SMART-1 station, in this paper, we firstly calculated the lagged coherencies under nine conditions which were combined with the three cut-off frequencies (8, 16, 24 Hz) and three separation distances (200, 1 000, 2 000 m). Then, we fitted the curves. Finally, the coherencies received according to nine groups of fitting parameters were compared. The conclusion can be drawn as follows: ① The selection of the cut-off frequency fcut has great effect on the parameters of coherence function model and lagged coherency fitting curves. ② The lagged coherency calculated by the fitting parameters which obtained by smaller cut-off frequency fcut decays rapidly with increasing frequency; on the other hand, the lagged coherency calculated by the fitting parameters which obtained by larger cut-off frequency fcut decays slowly with increasing frequency. ③ Great errors will be produced when using fitting parameters of the lagged coherency that got from the determined cut-off frequencyfcut to calculate the lagged coherency beyond that frequency range.

     

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