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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/65865

    Title: 龜山島周圍海域熱液與地震的關係
    Authors: 李聿文;Li,Yu-wen
    Contributors: 遙測科技碩士學位學程
    Keywords: 龜山島;SPOT;熱液;地震
    Date: 2014-07-24
    Issue Date: 2014-10-15 17:16:06 (UTC+8)
    Publisher: 國立中央大學
    Abstract: 沖繩海槽南端的擴張處於萌芽階段,海槽底部熱液活動十分活躍,且微震活動平凡,龜山島就位於沖繩海槽最南端,熱螢光定年法顯示島上擄獲岩的形成年代約在7000±700年前,可以將龜山島視為一座活火山,未來有再噴發的可能性。龜山島的後火山活動包含熱液和地震,熱液變化可能反應出活動的劇烈程度,目前島上沒有熱液的長期監測,所以本研究將地震當作活動指標,比對熱液變化與地震,借此得出熱液變化與火山活動之間的關係。
    ;Guishan Island is located at north eastern Taiwan belongs to Yilan County. According to geophysical and geochemical studies, Guishan Island is an active volcano, and the latest eruption occurred in the Holocene (7 ka). The active hydrothermal vents and earthquake can be considered as manifestations of volcanic activity. There are some hydrothermal vents at eastern offshore, and the fluids from the vents are mostly made up of sulfur, which cause the discoloration of the ocean around Guishan Island. The discolored area is called plume which can be easily detected by satellite image. The shape and size of plume are disturbed by ocean currents or winds. In this study, we detect the plume area by three steps: (1) remove land area; (2) remove cloud area; (3) classification. First, ENVI is used to build a mask and remove land area. Followed by a fully constrained least squares approach, it is a mixed pixel classification method for concentration estimation in each pixel. Finally, the area of plume is calculated from the result of least square approach, and then compare with the number of earthquake events to find the relationship between them. In our experiment, 36 SPOT images in 2008 are adopted, and the result shows that the larger area of plume was occurred around the large cluster of events. The area of plume is related to earthquake but there isn′t clear. After the correlation coefficient is calculated, the result shows the area of plume is related to the number of earthquake events. The highest correlation coefficient is 0.68 in ±1day. It means maybe the earthquakes can cause the area of plume become larger.
    The number of earthquake event is 425 and the number of image is 36. Although the number is uneven, the best way for long term monitor is satellite image until there is a direct measurement.
    Appears in Collections:[遙測科技碩士學位學程] 博碩士論文

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