地震是台灣地區常見的自然災害，危險性高卻至今仍無有效的空間或時間之預測方法，近年來由於GPS追蹤站的廣泛建立，GPS訊號解算電離層全電子含量(Total electron content, TEC)之震前擾動研究也日漸增加。因此本研究首先以台灣地區之GPS追蹤站資料解算電離層TEC值之時間及空間分布，從震前電離層觀測結果發現電離層每日高峰值在地震前數日出現降低或異常升高之現象，且震央附近之電離層在擾動期間內TEC值異常升高日也同時出現高濃度電子聚集現象。
本研究除分析震前電離層TEC值之空間及時間擾動外，另外利用超導重力儀(Superconducting gravimeter, SG)在部分地震前出現之持續擾動事件進行分析，經剔除為颱風所造成的擾動後，發現這些震前擾動的最大振幅與距離之反比呈線性關係，利用此關係由多站資料對擾動源進行空間約制，作為預測地震震央可能位置之推估。由震前擾動頻譜分析結果顯示此擾動具有穩定之主要頻率，且在測站離震央較遠之擾動其頻譜中有較多低頻訊號分布，與高頻訊號被大地吸收有關。測站與擾動源間斷層的位態亦會影響震前擾動訊號的偵測，當測站位於平行地震震源傾角方向時，偵測到震前擾動之機率及振幅均較高，因此綜合震前擾動空間約制條件及方向性結果，顯示在選擇SG測站之設置位置時，需兼顧測站間距及板塊邊界之方位才能獲得較佳之偵測效果。而比較電離層與超導重力儀之震前擾動時間，發現這兩種擾動可能同時出現，因此有可能是來自同一擾動機制，此機制與震前擾動時空分布特徵分析為本研究之主要工作內容。

Earthquakes are a common natural hazard in Taiwan. Studies on pre-seismic ionospheric total electron content (TEC) anomalies have recently been conducted using GPS data. From the time variance of pre-seismic ionosphereic TEC observations, anomalies can be detected several days before the main shock. An unusual ionospheric TEC increase during the days of pre-seismic anomalies also shows an electron concentration near the epicenter. Pre-seismic anomalies detected by the superconducting gravimeter (SG) for some earthquake events are also analyzed in this study. With anomalies caused by typhoons removed, pre-seismic SG anomalies show a linear correlation between the maximum amplitude and the inverse distance from the epicenter to the SG station. This result can be used to locate the epicenter of an earthquake from multiple SG stations. The spectrum analysis reveals that the perturbation is stable in the frequency domain. The amount of low-frequency energy preserved increases with traveling distance. The attitude from the SG station to the fault plane affects the amplitude of a pre-seismic anomaly and thus the possibility of its detection. The amplitude of a pre-seismic anomaly and the possibility of its detection are relatively high for stations parallel to the dip direction of the fault plane. Spatial constraints and the directional effect should be considered when determining suitable locations for future installations of SG stations. The pre-seismic anomalies of the ionosphere and SG data may be excited at the same moment. This result indicates that those two kinds of pre-seismic anomalies might be caused by the same unknown mechanism which could be linked to the upcoming earthquake.

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