根據台灣地區布蓋異常圖，宜蘭平原存在一明顯重力低區，初步認為此低區與該區堆積沉積物有關。且此區域地體構造同時受到島弧系統影響，為探討低區成因與其地質構造的模式，本研究藉由觀測重力資料，模擬二維、三維地下密度構造，推求宜蘭平原地區的地下密度模型，並透過重磁力異常分析，期望對該區地下構造與斷層分布提供更好的解釋。初始模型的假設，主要參考前人陸上地質剖面及海域震測剖面，配合相關地質圖，進行構造模擬，直到模型的理論重力值與觀測重力值相符，得到合適的地下密度構造分布。因為重力資料模擬地下構造的結果有非唯一解的問題，因此模型將參考鑽井、震測及速度構造資料，期能對深部構造有更好的控制。 According to the Taiwan Bouguer anamoly map, one of the low Bouguer anomaly areas, Ilan plain, may be caused by the thick sediments beneath it. Moreover, the tectonic structure of Ilan plain is also constrained by the Ryukyu arc system. For investigating the causes of low Bouguer anomaly distribution and the subsurface geological structure, we will use observational gravity data to model the 2-D and 3-D density structures. The suitable subsurface structure can be obtained by using the trial and error method and revising the initial model, referenced from geologic and geophysical data. Because of the non-unique problem in gravity modeling, we will combine drillings, seismic profiles, and tomography results to get better constrains of the deeper subsurface structure. 研究期間：9908 ~ 10007
