1999年集集大地震後，台灣不少研究學者針對西部重要的褶皺衝斷帶進行了相當多的構造地形研究，其中依據地形標記（如沖積扇，河階等）的特徵，配合其構造形態觀察到微小的地表變形。利用階地的錯位和年代的相互關係來探討構造運動，其中年代在討論構造演育上扮演關鍵的角色，影響界定斷層於百年或千年的活動速率。現今最常用的河階定年技術是14C定年法，除了定年材料尋找不易以外亦不適用於老於五萬年所形成的階地。宇宙放射線核素定年隨著分析儀器的進步越發蓬勃發展，是一相當有發展潛力的定年技術，利用分析宇宙射線粒子撞擊地表元素產生的新元素含量來進行模擬，藉由分析10Be、26Al的含量及兩者含量的比值變化與深度的關係（深度可逹10-20公尺），模擬階地的曝露年代、侵蝕速度，甚至曝露歷史相關的資訊。在理想條件下，現階段可估算及運用之年代範圍在幾千年至幾百萬年之間。本研究著重於河流沖積層的地形、形貌分析，其所呈現的地質及構造特徵，為了進一步探討地形特徵形成的年代以及構造活動的速率。本研究目標之一為應用宇宙放射性核素定年法於階地的出露年代，進而在不同時間尺度下探討區域的抬升與下切速率；其二為得到詳細的地貌量化和時間控制，進而重構西部麓山帶褶皺逆衝帶之地貌與構造演育。
After the 1999 Chichi Earthquake, several active structures are well study at the fold-and-thrust belt in western Taiwan. Some of these morphological marks (e.g. alluvial fan, river terrace, etc.) and tectonic characteristics have been observed from the surface deformation. Combined to the tectonic offsets, the chronological framework of emplacement and abandonment of these geomorphic markers is thus a fundamental data to determine fault slip-rates integrated over several tens to several hundreds of thousands years. But, alluvial material younger than 50 ky old could be dated through radiocarbon method the datable material is generally poorly preserved due to the weathering context. To achieve these scientific goals, the analysis should combine both the quantitative geomorphology and the statistical curve fitting from the cosmogenic nuclides concentration (10Be, 26Al) measured in alluvial terraces profile. Accurate dating requires both the quantities of the post-depositional production of 26Al and 10Be, and the sampling depths could be up to 10-20 meters. By using the cosmogenic radionuclide concentration at depth profile, the method deduces both the inheritance and the deposition age of the surface. This project is organized around methodological and thematic tasks aiming at characterizing deformation behaviour of different morphostructural units, activity changes along fault and landscape evolution. Within the highly active context of the western Taiwan, this project objectives are quantifying the uplift/incision rates at different time scales using in situ-produced cosmogenic nuclides in river-borne sediments and alluvial terrace deposits), and (2) reconstructing the tectonic and landscape evolution of the fold-and-thrust belt, detailed geomorphic quantification and time controls will be obtained using cosmogenic radionuclides dating.
