直流電阻之雙極排列法於頭前溪河面上調查新城斷層

新城斷層的存在，除了有明顯的露頭外，湯振揮(1968)以航照地質圖配合地表地質及寶山背斜之地下構造，判斷新城斷層是一個低角度的逆衝斷層。郭泰融(1991)在新城斷層做重力和反射震測的研究，結果也認為新城斷層是一個低角度的逆衝斷層。曹正宇(1997)併合多種地球物理探勘儀器於頭前溪兩岸施測，也發現地層中之電性不連續，進而判斷此斷層之存在。新城斷層露頭於頭前溪附近，發現斷層面橫跨頭前溪，本文嘗試利用地電阻之雙極排列法在頭前溪之河面上施測，由於斷層上下盤組成物質不同，在斷層帶附近勢必造成一電性不連續帶，尋找施測剖面中電性不連續帶，評估直流電阻之雙極排列法調查水體面下地層變化情形的可行性。

關鍵字

新城斷層；水體面下地層變化；雙極排列法

並列摘要

By using pole-pole array DC resistivity method for electrical imaging or electrical tomography, it is successful to map the geological structures on land being reported. However, it is rare reported by applied on underwater mapping. This paper demonstes a potential of electric imaging which were applied on water surface to survey for underwater structures. We will show the result from the surveys performed at Sincheng -Fault to demonstrate this new application. In this case, we tried to explore the location of a underwater thrust fault underneath a river bed. The results do assist in interpretating underwater structures. Therefore the techniquede clearly demonstrated its capability of resolving underwater stratigraphy.