在海洋地區，一般計算岩石圈彈性厚度是利用重力與地形的關係求得，而其彈性厚度接近450°C等溫線的深度。但對大陸岩石圈而言，其彈性厚度變化則較為劇烈，影響的因素也多。從台灣南部至馬尼拉隱沒帶北段，隱沒的歐亞板塊其組成有很大的不同，包含從北部的大陸地殼-轉換帶至單純海洋地殼隱沒。TAIGER (Taiwan Integrated Geodynamic Research program)在這區域收集了反射及折射資料，其剖面結果可清楚判識slab的位置，在海溝區域slab的幾何更能表現板塊受力變形的樣貌。本研究要利用模擬在這區域slab撓曲的特性得到彈性板塊的資訊，希望藉由這些資訊能讓我們多了解歐亞板塊在這過渡帶組成的變化。另一方面，南海海洋地殼的年紀已經由IODP鑽井結果得知，計算南海海洋岩石圈彈性厚度可讓我們進一步比對海洋岩石圈彈性厚度與地殼年代間的關係，討論其是否符合過去在其他區域的研究結果，其差異如何。 ;In oceanic regions the effective elastic thickness (EET or Te) of the lithosphere is generally estimated from gravity anomaly and topography and approximately corresponds to the depth of the 450°C isotherm. However, in the continents the exact physical meaning of Te is unclear, and a number of properties are important in its control. From onland southern Taiwan to the northern Manila subduction zone, the properties of the subducting Eurasian plate are very complicated, which includes a continental part in the north and an oceanic part in the south. The Taiwan Integrated Geodynamic Research program (TAIGER) collected three wide-angle and reflection seismic transects (T1, T2, and T4A) across the northern Manila subduction zone and southern Taiwan that provide well constraints on the slab geometry. Thus, unlike previous studies, in this study, we try to adopt a better way using synthetic flexure to fit the observed slab which can actually reflect the deformation of the plate. And we expect that the estimates result can give us some information about the compositions of the Eurasian plate. On the other hand, the ages of the oceanic crust in the South China Sea (SCS) were well known. To estimate the Te of the SCS lithosphere could let us better understand the relation between Te and the ages of the oceanic crust.