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Time‐Frequency Signal Analysis of Earthquake Records Using Mexican Hat Wavelets
Author(s) -
Zhou Ziqin,
Adeli Hojjat
Publication year - 2003
Publication title -
computer‐aided civil and infrastructure engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.773
H-Index - 82
eISSN - 1467-8667
pISSN - 1093-9687
DOI - 10.1111/1467-8667.t01-1-00315
Subject(s) - wavelet , signal (programming language) , seismology , wavelet transform , time domain , acceleration , peak ground acceleration , continuous wavelet transform , geology , computer science , ground motion , discrete wavelet transform , physics , artificial intelligence , computer vision , classical mechanics , programming language
A method is presented for time‐frequency signal analysis of earthquake records using Mexican hat wavelets. Ground motions in earthquakes are postulated as a sequence of simple penny‐shaped ruptures at different locations along a fault line and occurring at different times. The single point source displacement of ground motion is idealized by a Gaussian function. For the purpose of signal analysis of accelerograms, the ground motion record generated by a simple penny‐shaped rupture is used to form the basis wavelet function. After a careful study of the characteristics of various wavelet functions, the Mexican hat wavelet was found to be the most appropriate wavelet basis function to represent the acceleration of a single point source rupture. The result of the signal processing of an accelerogram is presented in the form of a scalogram using the coefficients of the continuous Mexican hat wavelet transform to describe the signal energy in the time‐scale domain. The proposed signal processing methodology can be used to investigate the characteristics of accelerograms recorded on various types of sites and their effects on different types of structures.