Using the variation of energy integral to analyze the property of debris flow
Date Issued
2006
Date
2006
Author(s)
Lin, Chi-yu
DOI
zh-TW
Abstract
By using Fast Fourier Transform, we transformed the data from time domain to frequency domain and integrate a range of frequency domain in order to obtain the accumulative energy curve and to analyze the debris flow event.
First of all, we consider four ranges of characteristic frequency of debris flow which ranges from 0-40Hz, 40-80Hz, 120-160Hz and 160-200Hz.
Secondly, we do the experiment by using an iron ball to hit gravels and use a high speed CCD to catch images. Then we compare the images with time domain signals and frequency domain signals.
Finally, we analyze the geophone data from debris flow event occurred in Aiyuzi River, Nantou County on July 2, 2004 by using energy integral method. We integrate the energy between the specific ranges for a one minute and every 0.001 minute record. Then calculate the time increment. In this way, we obtain the variation of the energy integral of the characteristic frequency of debris flow per minute and every 0.001 minute. We use the variation to compare with the time domain signals and the CCD image. It is found that the result can pinpoint the properties of debris flow. We prove that the energy integral method is a practicable method and it may be used for debris flow warning in the future.
Subjects
土石流
地聲探測器
快速傅立葉轉換
能量積分
debris flow
geophone
FFT
energy integral
SDGs
Type
thesis
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