| Summary: | 碩士 === 國立臺北科技大學 === 土木與防災研究所 === 93 === Located on the Eurasia plate and the Philippine marine plate to push with the lasting, where earthquakes happen frequently, Taiwan, due to particularity with complicated geography character, was attack by earthquakes. Earthquake is a natural proceeding in which the earth releases energy. It is not the manpower that can be controlled, through verifying that relation with a certain level of education in groundwater level change and the earthquake appears. Besides, there are well network observing groundwater changes in Taiwan. For observing groundwater, we get certain advantage. Searching how to decrease the damage caused by earthquakes, we must study the correlation between groundwater and earthquakes.
Observe the monitoring station of Nabal and Liujar as the research object, at the Jarnan strong shock earthquake groundwater network in this research. In order to probe the earthquake incident, whether produce the unusual behavior to the groundwater level, make using observed of groundwater level time sequence to analyze the change amount of the groundwater level clicked, in time before and after an earthquake attack. In order to prevent the earthquake incident from being influenced by incidents, such as ground tide , rainfall ,etc. Causing the wavelet analyse obtain the accurate result, the unusually high frequency be unable diagnose. The Artificial Neural Network(ANN) is so utilizing to detrend of rainfall, ground tide, and irregular signal, etc.
Detrend of morning and evening tides, rainfall time series through kinds of ANN. Using the Wavelet theory to explore the long-time groundwater level examines the amount layer of structure separately, and uses the Wavelet transform and calculate the Wavelet coefficient, can assess various mixing interweaving kinds of the groundwater level signal by calculation of Wavelet coefficient value, resolve into and distinguish layer or different frequency block signals at differently level, and then, using Wavelet shrinkage method by Donoho and Johnstone, to estimating and examining the Wavelet coming out in development of the signal. Choose a suitable critical value, to clipping the high-frequency Wavelet coefficient. And then, using threshold to shrink wavelet coefficient, and clipping out the approximation function and the detail function of underground water level attack by just earthquake. Taking that obviously of this point out groundwater level appear frequency unusual time, therefore will contribute to reducing natural disasters, will lengthen and take refuge and reflect time.
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