地表震動監測為近年來重要的土石流事發型監測方法，但是事發型監測方法的缺陷為應變時間短。為了改善這個缺點，本研究期望藉由濾波器提分析地表震動訊號，提前土石流的偵測時間。本研究藉由四種不同的數位濾波器(巴特沃斯濾波器 (Butterworth filter)、橢圓形濾波器 (Elliptic filter)、切比雪夫一號濾波器 (Chebyshev Type I filter)、切比雪夫二號濾波器 (Chebyshev Type II filter) )提取土石流波湧前端訊號，並且以地表震動強度分析取得背景雜訊的平均強度作為參考閾值。而土石流接近震動感測器時的震動強度若高於閾值，則判斷為土石流的偵測時間。三起作為分析樣本的土石流事件中，兩起由地聲檢知器 (Geophone) 量測得，一起由光纖加速度計 (Fiber Bragg Grating Accelerometer) 量測得。由分析結果可知，地聲檢知器所量測得的訊號經過數位濾波器保留特定區段後確實可以提前土石流偵測時間，原因為地聲檢知系統的系統內雜訊太多，造成訊號品質不良，藉由濾波後可將雜訊排除，達到提升訊號品質、提取土石流前端訊號並提前土石流偵測時間之功用。而光纖感知系統所量測得之訊號則因來自系統內部的雜訊較少，濾波器將其品質提升的程度有限，所以提前偵測土石流的效果也有限，訊號濾波前後所估算的土石流偵測時間並無明顯差異。

Ground vibration monitoring is one of the most important techniques as a real-time monitoring system of debris flow events. However, the limitation of the ground vibration monitoring system results in a short period of reaction time to evacuate the inhabitants before the debris flow disasters arrive. To improve the limitation of this system, this study analyzes ground vibration signals with signal processing filters to be early the disaster warning time. Four different signal processing filters, including Butterworth, Elliptic, Chebyshev Type I, and Chebyshev Type I filters are used to identify the ground vibration signals of the surge front resulted from the debris flows. The threshold levels of the average intensity of the ambient noise are indicated by an analysis of ground vibration intensity. The detected time of a debris flow is defined while the intensity of the ground vibration signals exceeds the threshold level. The first two cases to analyze ground vibration signals are measured by the geophones, and the last one is evaluated by the fiber bragg grating accelerometer. The results determine that the disaster warning time estimated with these signal processing filters are earlier than original ones because the noise from the geophone system are obviously sufficient to overlap the debris flow signals. In the case of fiber system, those signal processing filters did not improve the quality of the signal as much as they work on the geophone signals since the noise generated from the fiber system are much lower than those from the geophone system. As a result, the debris flows detected time seems without significant improvements even though the signal processing filters are implemented to modify the row signal data.

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