基于快速傅里叶变换的地震波加速度构成及其幅频特性研究  

Composition and amplitude-frequency characteristics of ground motion acceleration based on fast Fourier transform analysis

作　　者：付荣[1,2] 傅荣华[2] 付安生 

机构地区：[1]山西省第三地质工程勘察院,中国山西晋中030620 [2]成都理工大学环境与土木工程学院,中国成都610059

出　　处：《地震学报》2014年第3期417-424,531,共8页Acta Seismologica Sinica

基　　金：国家自然科学基金(41072228)资助

摘　　要：根据2008年汶川MS8.0地震广元曾家台(GYZJ)的强震记录,运用Matlab软件对东西向55—75s的加速度时程进行快速傅里叶变换,得到有限复傅里叶系数,从而将离散的加速度记录转化为加速度随时间变化的函数表达式.该表达式中包含了50组不同频率的正弦波和余弦波,由此确定了地震波加速度的主要构成.经回归分析可知,函数计算值与原始记录的相关系数R为0.9,拟合程度良好;利用SeismoSignal软件对地震波加速度时程进行谱分析,结果表明在原来的波中频率约为2.8Hz的谐振分量振幅最大且0—10Hz这一频段的波最为丰富.这一结果与函数表达式中频率与振幅的分布基本吻合,为深入研究汶川地震的动力特性及其对山体动力效应的分析提供了重要的理论依据,具有广阔的应用前景.This paper analyzed the strong ground motion records of the 2008 Wenchuan Ms8.0 earthquake at the station GYZJ,and used Matlab software to carry on the fast Fourier transform on the acceleration records of E-W component in 55-75 s,and then obtained a function expression of the acceleration variation with time.The expression contains 50 groups of sine and cosine waves with different frequencies,which are the main composition of the seismic wave.A correlation coefficient of 0.9 deduced from regression analysis shows well fitting between the calculated values and observed records.In addition,we used the SeismoSignal software to analyze the spectrum of the ground motion acceleration.Our results show that the harmonic component with frequency of 2.8 Hz in the original wave has the maximum amplitude and a dominant range of seismic waves has a frequency band of 0-10 Hz.These results generally agree well with the frequency and amplitude distribution of the functional expression.This paper provides an important theoretical basis for the research of wave characteristics and the analysis on the dynamic effect of slope in Wenchuan earthquake.

关 键 词：强震记录 加速度 快速傅里叶变换 幅频特性 

分 类 号：P315.31[天文地球—地震学]