Estimation of the duration of the earthquake using discrete wavelet theory

Document Type : Original Article

Authors

1 Department of Civil Engineering, University of Isfahan, Isfahan, Iran

2 Civil Engineering, Shahrekord University

3 Department of Civil Engineering, Islamic Azad University Isfahan (Khorasgan) Branch, Isfahan, Iran.

Abstract

In this research, discrete wavelet theory has been used to the decomposition of the earthquake acceleration wave and to estimate the duration of its strong motion. For this purpose, first, the 4 acceleration waves of the main earthquake are refined using a band-pass filter in order to remove the errors that occurred during the earthquake recording. Then the modified acceleration wave is decomposed into 5 levels using discrete wavelet theory. In each step of the filter, two approximate and detail waves are obtained, by using the rule of sampling reduction by removing the detail wave in each step, the number of earthquake points is half of the previous step. There are different ways to determine the time of an earthquake. These methods include uniform, bracket, important and effective time. In this article, the time of earthquake occurrence is obtained by each of the mentioned methods with the help of wavelet theory. For this purpose, from each of the approximate waves, the earthquake occurrence time has been calculated and compared with the time obtained from the main earthquake. The obtained results show the ability of the wavelet theory to estimate the earthquake time. The error of earthquake occurrence time for approximate waves obtained from wavelet transform is less than 7%.

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Asas Journal
Volume 24, Issue 67
Summer 2022
September 2022

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History

  • Receive Date: 06 October 2018
  • Revise Date: 05 April 2023
  • Accept Date: 15 April 2023

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