臺灣島四面環海、地形陡峭及地質構造複雜。海水及維度效應對大地電磁資料的影響程度甚鉅。在二維張量分解模型中，利用旋轉矩陣消除非對稱參數，但實際應用卻無法將其完全消除，被僅能以趨近或忽略不計，無法滿足真實三維構造所反映的地層資訊，尤其是埋存於地殼中的高導體最為棘手。因此，本計畫預計利用三維大地電磁模擬技術，探討海水及維度效應對大地電磁資料的影響程度，進而分析全臺大地電磁資料庫(移動與監測站)及水下大地電磁資料。整合比對海、陸大地電磁資料，分別探討電性構造位於在隱沒板塊邊界、被動大陸斜坡邊緣與造山運動帶之差異與地體構造之關聯性，預期將有助於深入了解臺灣地區的地體構造演化之科學議題。 Taiwan Island is surrounded by the sea, precipitous terrain and geological complex region. The magnetotelluric (MT) responses would be seriously affected by the surrounding sea and the complex structure, so call ocean and dimensionality effect. Due to off-diagonal parameters of two-dimensional (2D) cannot be completely decomposed by a rotated matrix, only to approach or ignore, based on 2D tensor decomposition model. It does not directly reflect to the varied 3D electrical structure and the real stratigraphic information, especially high conductor anomaly buried in the crust. Therefore, this project aims to take advantage of three-dimensional MT modeling techniques to understand the degrees of ocean and dimensionality effect. Furthermore, to analyze the whole MT database (mobile and monitor stations) and marine MT dataset. Integrating onshore and offshore MT data located in subducted plate margin, orogeny and passive continental margin to be respectively compared in order to study electrical structure associated with the Taiwan tectonics. This project is expected to much help understanding Taiwan’s tectonic evolution.
Deep electrical structure