台灣關於地球物理方面研究已有三十多年，至今也已建立許多監測網，包括數種功能不同之地震觀測網、GPS觀測網、地殼潛變觀測網、磁力觀測網等等。在國科會大力支持下，在前一年度，我們也終於建立了兩個大地電磁固定觀測站。本研究主要使用之方法－大地電磁法，其資料收集主要為接收地球上天然電磁波擾動之寬頻帶電磁資料記錄，頻率範圍可從數百至數萬分之ㄧ赫茲。這種被動式收集之天然電磁波訊號，包含了磁場與電場隨時間之變化。而大地電磁法之資料響應，通常用來分析不同頻率之電磁阻抗，其可對應於測點從淺至深之地下介質電阻率變化。台灣各處多有人為開發，造成的電力雜訊常可影響大地電磁法之訊號品質，目前研究方法上普遍使用遠端參考訊號，以修除區域雜訊，建立起長期監測站將可幫助此一困境之突破。此外長期監測站並可提供研究電磁波的長時間變化，前人研究已發現，電磁波的變化在在可能受環境改變的影響，例如地震活動、火山活動等。長期監測站能提供一個穩定的背景觀測，進一步進行電阻率長期變化之研究、追蹤地震活動之事件，以及監測其他可能影響電磁波之活動。本研究將在整合型計劃的框架下，結合各個子計劃之資料，共同探討可能存在的電磁波震前訊號。 For the geophysical community, there are many continuous observations around Taiwan which included several different kinds of seismic network, GPS network and magnetic network. Magnetotelluric method is a method collecting the natural variations of the electromagnetic waves in a wide frequency range. The application of MT is limited from manmade electromagnetic noise around Taiwan, which reduces the data quality in the early stage of MT in Taiwan. Data could be in general processed by the remote-reference technique for increasing the signal-noise ratio. Under the support of NSC, we have established two stationary observations for MT researchers in Taiwan. Recently, co-seismic EM phenomena induced by seismic wave have been observed in our MT signals. In this study we are furthermore planning to look for possible pre-seismic signals from our stationary MT observatories, jointly with some other geophysical precursor under the framework of the joint project. 研究期間：9908 ~ 10007
