https://scholars.lib.ntu.edu.tw/handle/123456789/45766
標題: | Velocity Structure in Marine Sediments with Gas Hydrate Reflectors in Offshore SW Taiwan, from OBS Data Tomography | 作者: | Cheng, Win-Bin Lee, Chao-Shing Liu, Char-Shine Schnurle, Philippe Lin, Shiao-Shan Tsai, Hong-Ruai |
關鍵字: | Gas hydrates; Methane migration; OBS seismic data; Seismic tomography | 公開日期: | 2006 | 卷: | 17 | 期: | 4 | 起(迄)頁: | 739-756 | 來源出版物: | Terrestrial, Atmospheric and Oceanic Sciences | 摘要: | In the fall of 2004, four profiles of a total length of about 80 km and 24 recovered Ocean Bottom Seismometers (OBSs) were acquired along off-shore southwestern Taiwan. These profiles were oriented in E-W and N-S directions to map the velocity structure of sediments by modeling the vertical component of OBS data. The thickness of sedimentary layers ranges from a few hundred meters to about 2 km, with the largest thickness being found beneath ridges. The most striking feature in the velocity models along E-W profiles is the relatively high velocity wedges, extending from the seafloor to about 2 km in depth; these could be interpreted as a series of westward upthrust faults. The feature of relatively high P-wave velocity could be considered a result of local shallowing of the base of the gas hydrate stability zone, caused by ascending flows of deep fluids passing through the fault zone. In the N-S profiles, a dome-like high velocity structure was observed and could be associated with the phenomenon of hydrate/gas phase boundary fluctuation. After erosion, the sub-seafloor temperature gradient redistributes and results in the hydrate/gas phase boundary moving downward. The results obtained in this study show that tectonic control is an important factor in determining bottom-simulating reflector (BSR) distributions offshore of southwestern Taiwan. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/173967 http://ntur.lib.ntu.edu.tw/bitstream/246246/173967/1/38.pdf |
DOI: | 10.3319/TAO.2006.17.4.739(GH) | SDG/關鍵字: | marine sediment; numerical model; seafloor; seismic data; seismic reflection; seismic tomography; seismometry; tectonic setting; temperature gradient; velocity structure |
顯示於: | 海洋研究所 |
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