台灣受到歐亞板塊與菲律賓海板塊之間的碰撞運動影響，斷層分布密集，且地震頻繁。為了探討台灣的地殼變形行為及各斷層孕震潛勢，本研究利用Robert McCaffrey所提出的三維塊體模型DEFNODE(MaCaffrey, 2002;2005)反演285個2006年至2014年的GPS連續站及841個2002年至2014年的移動站之水平速度場，以得到主要斷層上的長期滑移速率及滑移虧損率。本研究依據中央地質調查所公佈之28條斷層及其他構造邊界，將全台灣分為34個塊體，經由估算塊體間的相對運動求取斷層上的長期滑移速率。此外，為了使模型解算出的斷層滑移速率與地質觀測資料吻合，本研究加入了最新發表的地質滑移速率當作反演時的約束值。結果顯示北部地區的斷層長期滑移速率及滑移虧損率普遍偏小，平均約小於3 mm/yr；中部地區則以車籠埔斷層、大尖山斷層及觸口斷層等西部麓山帶的斷層之長期滑移速率與滑移虧損率較大，分別約為8至13 mm/yr及7 mm/yr；南部地區也是以西部麓山帶的梅嶺斷層及小崗山斷層具有較大的長期滑移速率與滑移虧損率，其平均長期滑移速率與平均滑移虧損率分別為23.0至27.0 mm/yr及7.0至10.0 mm/yr；東部地區的縱谷斷層北段之長期滑移速率(11.0 mm/yr)雖小於南段(16.3 mm/yr)，但其滑移虧損率(4.3 mm/yr)則是高於南段(0.9 mm/yr)，顯示了縱谷斷層南段的潛移特性，但鹿野斷層則顯示出14.4 mm/yr的高滑移虧損率。本研究並利用所求取之滑移虧損率來估算各斷層的測地矩率及上一次活動至未來50年的地震潛勢，結果顯示多數斷層之規模較特徵地震規模來得低，北部與中部地區斷層之規模約介於6.0至6.5；南部的旗山斷層及恆春斷層因上一次活動距今較久，因此估算出的規模達7.5以上；而縱谷斷層北段估算出的規模為7.0，比縱谷斷層南段的6.5來得高。;Taiwan has been experiencing the collision between the Eurasian and the Philippine Sea Plates, therefore many active faults and abundant frequent earthquakes have been formed. In order to evaluate the earthquake potential of potentially hazardous faults, I applied amethod of block modeling to invert the horizontal velocities of 1126 GPS stations, including 285 continuous and 841 campaign stations for the long-term slip rates and slip deficit rates of 28 active faults published by the Central Geological Survey of Taiwan.To do this, I divided Taiwan into 34 blocks, with their motions referenced to the passive continental margin of the Eurasian Plate. Three models were set in this study, where the first one considers only block rotations and fault coupling effects and the second includes internal strain within the blocks. To examine the consistency between the geodetic and geological slip rates, moreover, I applied a newly published dataset of geologic fault slip rates to constrain the inversion process as the third model. The results revealed that the long-term slip rates and slip deficit rates are lower (< 3.0 mm/yr) in northern Taiwan and higherin the Western Foothills in central (8.0‐13.0 mm/yr and 7.0 mm/yr) and southern Taiwan (23.0‐27.0 mm/yr and 7.0‐10.0 mm/yr). The south part of the Longitudinal Valley fault hasa higher long-term slip rate (16.3 mm/yr) but lower slip deficit rate (0.9 mm/yr) than the north segment (11.0 mm/yr and 4.3 mm/yr), indicating the interseismic creeping behavior of south segment of the Longitudinal Valley fault. I estimated the earthquake potential from the most recent event to the next 50 years and compared to the magnitudes of characteristic earthquakes. My results infer that the earthquake with magnitude of larger than Mw 6 might occur on the faults in northern and central Taiwan. The magnitudes of the Chishan Fault and the Hengchun Fault are larger as Mw 7.5 because they are far from their recent activities. The magnitude of the north part of Longitudinal Valley (Mw 7.0) are higher than the south part (Mw 6.5).
