台灣位於歐亞大陸板塊與菲律賓海板塊之聚合帶，構造活動相當頻繁，除了東部縱谷斷層之活動較為劇烈以外，西南部地區之近期活動受到相當重視。台灣西南部的褶皺—逆衝斷層帶是目前正在活動的構造帶，近幾年來頻繁的地震活動說明了該地區的地殼變動可能處於一個較為活動階段。許多地球物理研究針對西南部的構造運動進行探討，研究顯示該地區除了聚合運動外，亦歸納出了幾個構造因素：(1)北港高區的幾何形狀，(2)西南部的構造(斷層)分布，(3)南部增積岩體的延伸。 本研究針對台灣西南部的台南台地地區構造活動進行觀測。台南台地為一橢圓形的構造高地，北端有鹽水溪，南端有二仁溪，其長軸呈北北東—南南西向，南北長約12公里，東西寬約4公里，最高點於台地偏東側高度約30公尺。台南台地的東側為一陡坡，此為後甲里斷層所在，長約11公里。台南市位處於台南台地之上，人口密度頗高，為台灣第四大城市，因此後甲里斷層的活動性是一項重要的課題，嚴重關係區域的民生問題。 近幾年來太空遙測技術應用於大地測量日趨完善，其優點為能有效對大範圍區域進行連續觀測，其資料精度也達到公分級的程度，因此太空遙測已成為地表監測的一項利器。本研究將利用太空大地測量法對研究區域進行監測，並對所接到的資料加以分析；研究共利用三種方法：(1)雷達差分干涉技術(DInSAR) (2)永久散射體(Permanent Scatterers)干涉技術(3)GPS大地應變場分析。初步成果顯示：(1)雷達差分干涉法得到台南台地平均為1.0cm/yr的抬升速率，大彎低地約0.5m/yr沉降速率；(2)台南台地之南北段有不同的抬升速率，推測受到地下基盤厚度及構造的影響；(3)由應變場分析推測台南台地構造變形模式為斜向壓縮的變形模式。此外本研究亦針對新開發之永久散射體干涉技術進行試驗，並探討其應用於大地測量的可行性。 The Taiwan mountain belt is an active collision belt and thrust wedge, which developed as the result of the oblique convergence between the Philippine Sea plate and the Eurasian plate. In addition to the Longitudinal Valley of eastern Taiwan, the suture between these two plates, the foreland area of western Taiwan is also under active deformation. Previous researches and current geophysical data suggest that the geology of SW Taiwan is influenced by (1) the foreland structural highs; (2) the major fault zones in the belt; and (3) the presence of a subduction zone to the south. Therefore modern geodetic monitoring of this area is essential to further improve our knowledge. The Tainan tableland is a structural high due to the active shortening. This tableland is located in the SW Tainan county, and is bound by Yen-Shuei Hsi river to the north and Er-Ren Hsi river to the south. It is 12km long in N-S direction and 4km in width, and the highest point of this tableland is about 30m. Tainan city is just situated on the Tainan tableland, this city is highly populated and is the fourth biggest city in Taiwan. To the eat of Tainan tableland, the Houjiali fault is documented as an active fault. In this study we try to detect the deformation activity in Tainan area and to discuss its deformation behavior. Recently, remote sensing technique has attracted many interests. In our study, we used many kinds of remote sensing method to delineate the deformation of Tainan area, these are (1) Differential Interferometry Synthetic Aperture Radar, (2) Persistent Scatterer InSAR, and (3) the strain rate field from GPS data. Our study shows that(1) the uplift rate of Tainan tableland is approximately 1.0cm/yr and the subsidence rate of Tawan lowland reaches about -0.5cm/yr revealed by DInSAR observation; (2) the differential deformation rate occurred in and around the Tainan tableland is principally controlled by the basement geometry and the local structural distribution; (3) the strain rate field shows that the Tainan tableland and its neighboring area are transpression in its deformation type. Further researches concerning the Persistent Scatterer InSAR technique and its related application are also stated in this thesis.
