https://scholars.lib.ntu.edu.tw/handle/123456789/45112
Title: | 「地震及活斷層研究」-孕震帶構造─台灣西南海域活斷層的調查與孕震構造研究(II) | Authors: | 劉家瑄 | Keywords: | 台灣西南海域;反射震測;脫序逆斷層;變形前緣;Offshore Southwestern Taiwan;Seismic reflection;Active faults;Deformation front | Issue Date: | 2003 | Publisher: | 臺北市:國立臺灣大學海洋研究所 | Abstract: | 本研究以兩年的時間分析探討了台灣 西南海域的地形與反射逆斷層資料,以調 查測繪台灣西南海域斷層分布與活動型 態。由於台灣造山帶由北向南發育,從台 灣西南海域向北到陸上造山帶,在空間上 提供了一個觀察從無震的斷層構造演化為 孕震帶斷層構造( seismogenic fault structure)。本研究的一個重點即在於探討 分析在台灣南部海域中的一條主要脫序逆 斷層從南往北的構造變化。本計畫執行的 兩年中,收集整理了通過此主要逆斷層的 多條逆斷層剖面進行分析,發現從南到北 其斷層幾何形態有相當的變化。 在西南海域活斷層的分布與活動型態 方面,本研究分析了高解析度的水深資料 及反射震測資料,觀察到大陸地殼開始進 入隱沒帶時在增積岩體上所形成的特殊構 造型態。台灣西南海域增積岩體靠近南海 大陸坡的一側發育出許多線性構造,這些 線性構造主要受到弧陸碰撞擠壓作用造成 的台灣西南地塊向西南方向逃脫(tectonic escape)作用影響,另加上原大陸邊緣基盤 形貌的控制。本年度完成一篇探討這個地 區特殊構造的論文,正送國際期刊審查 中。此篇論文報導了在台灣西南海域增積 岩體前緣的活動斷層研究,發現變形前緣 的構造在大陸斜坡上改為雁行狀排列而非 一個單一構造。同時研究發現的一系列線 形斷裂構造也證實研究地區正向西南方向 移動。 This 2-year research project intends to investigate the active fault systems and their seismogenic properties in the area offshore southwestern Taiwan. This report presents the two-year study results. In the active fault investigation, high-resolution bathymetry map of the study area has been compiled which reveal distribution of complicated fault systems. Unique structural pattern has been observed that shows the effect of the continental margin crust to the development of the accretionary wedge near Taiwan. Many topographic lineaments have been developed 3 on the frontal portion of the accretionary wedge off southwestern Taiwan. These lineaments could be developed due to the tectonic escape of the southwestern Taiwan block during the arc-continent collision processes. The different nature of the continental margin crust (from oceanic crust in the south to continental crust in the north) also contributes to the unique structural pattern observed. A manuscript describing this study result has been submitted to Marine Geophysical Research and is under review. Original idea of extract fluids from fault scarps to study the fault properties of a major out-of-sequence thrust in the first year of this project did not provide useful information, thus the focus was shifted to seismic study during the second year. Several seismic reflection profiles running across this major out-of-sequence thrust have been analyzed, and it appears that from south to north the fault plan geometry has changed following the transition from subduction to collision. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/14816 | Other Identifiers: | 912119M002018 | Rights: | 國立臺灣大學海洋研究所 |
Appears in Collections: | 海洋研究所 |
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912119M002018.pdf | 30.05 kB | Adobe PDF | View/Open |
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