宜蘭位於台灣東北部，受菲律賓海板塊向歐亞板塊隱沒擠壓，導致宜蘭地區與琉球島弧系統的構造十分複雜。前人研究中指出菲律賓海板塊往西北隱沒時，有產生類似旋轉的深層構造，而梨山斷層貫穿宜蘭地區與琉球島弧，扮演十分重要的角色，為探討此地區構造機制與形貌幾何，本研究結合陸上、海上與空載三種重力資料來源，模擬三維地下密度構造，推求宜蘭地區與琉球島弧的地下密度模型，並進一步分析此區板塊與隱沒帶作用的模式，期望對該區地下構造提供更好的解釋。初始模型的假設，因為重力資料模擬地下構造的結果有非唯一解的問題，主要參考前人陸上地質剖面及海域震測剖面並加入三維速度模型，配合相關地質圖，期能對構造有更好的控制。 The structures between Ilan and Ryukyu arc area located at northeastern Taiwan are complex in tectonic significance by subducting and collision from Philippine Sea Plate and Eurasian Plate. The studies refer that Lishan fault plays an important role for a clockwise rotation structure beneath the area caused by PSP subducting to EP. For understanding the further detail information about tectonic geometry and mechanism of subduction zone, we combine land, marine and airborne gravity data to model the 3D density structures beneath Ilan and Ryukyu arc areas. Because of the non-unique problem in gravity modeling, the assumption of initial model will use geology, drillings, seismic profiles and 3D tomography data as references to get better constrains of the structures 研究期間：10008 ~ 10107
