泸定6.8级地震强震动数据的Kappa参数研究  

A study of Kappa parameter(κ)of Luding Ms6.8 strong ground motion records

作　　者：张潇男 王海云[1,2] 李强 白云鹏[1,2] ZHANG Xiao‑nan;WANG Hai‑yun;LI Qiang;BAI Yun‑peng(Institute of Engineering Mechanics,China Earthquake Administration,Harbin 150080,China;Key Laboratory of Earthquake Engineering and Engineering Vibration,China Earthquake Administration,Harbin 150080,China)

机构地区：[1]中国地震局工程力学研究所,黑龙江哈尔滨150080 [2]中国地震局地震工程与工程振动重点实验室,黑龙江哈尔滨150080

出　　处：《振动工程学报》2024年第12期1993-2002,共10页Journal of Vibration Engineering

基　　金：中国地震局工程力学研究所基本科研业务经费资助项目(2018B05);国家自然科学基金地震联合基金资助项目(U2139207)。

摘　　要：地震动模拟通常为地震记录缺乏地区的建筑物抗震设防提供参考,高频衰减因子κ是地震动模拟的重要参数,控制着地震动傅氏谱高频下降的形状。本研究基于泸定6.8级地震记录,使用帕曾窗对原始记录的傅氏谱进行平滑,选择傅氏谱上p^(H)函数最小的频率区间作为高频衰减频段,能够准确识别高频衰减的起止频率,提高了计算的稳定性。共计算了20个数据质量较高台站的水平向κ,并对κ分布趋势进行了分析,分析结果表明:随着帕曾窗窗宽的增大,傅氏谱逐渐平滑,窗宽大于1Hz则会与原始谱出现明显偏离;比较12个窗宽的帕曾窗对傅氏谱平滑的效果,0.4Hz窗宽最佳,可使曲线平滑且计算的κ误差小;κ分布有明显的方向性差异,在东西向κ随震中距增大而明显增大,在南北向随PGA的增大而明显减小。Ground motion simulation can provide reference for buildings seismic design in areas lacking earthquake records.High frequency attenuating factor(κ)is an important parameter in ground motion simulation,controlling the drop of Fourier spectrum shape in the high frequency interval.Luring magnitude 6.8 earthquake records within 150 km of the epicenter are selected to developκ.Parzen window is used to smooth the cluttered Fourier amplitude spectrums(FAS).The frequency interval in FAS with the smallest p^(H)function is selected to fit theκ.The approach improves accuracy of identifying lowest and upper frequency,and the stability of the calculation.κare calculated based on 20 stations of horizontal records and the distribution trend ofκis analyzed.The results show that FAS is gradually smooth with the increase of the window width,and it is significantly different from the original spectrum when the window width is larger than 1 Hz.Compared with 12 window widths,the window width of 0.4 Hz is the best.The window of 0.4 Hz width makes the curve smooth and the error ofκsmall.There is a significant directional difference inκdistribution.κin EW direction increases with respect to epicenter distance,andκin NS direction decreases with respect to PGA.

关 键 词：地震动 高频衰减因子 帕曾窗 傅氏谱 泸定地震 

分 类 号：P315.91[天文地球—地震学]