Physiographic Characteristics of the Continental Margin, Northeast Taiwan

臺灣東北海域大陸邊緣地形區之特徵

俞何興(Ho-Shing Yu) ； 洪奕星(Eason Hong)

《Terrestrial, Atmospheric and Oceanic Sciences》 3卷3期 (1992/09) Pp. 419-434

摘要

臺灣東北海域之大陸邊緣包括五個主要地形區，即東海大陸棚、東海大陸斜坡、南沖繩海槽、宜蘭大陸棚及宜蘭海脊。這個地形區架構是暫定的，如果有更好的的名稱提出則修改之。
東海大陸棚相當地寬，且其海床平坦，但局部有明顯的地貌起伏，這是受到晚更新世海水面升降及弧後盆地張裂的火山活動影響。
東海大陸斜坡的地形及坡度其側向變化極大，大陸斜坡上有明顯的崩塌或滑動斷崖、侵蝕槽谷、碎屑流或濁流沉積物。海底峽谷是大陸斜坡另一明顯的地貌，其頭部嵌入大陸棚，使棚坡區域形成不規則狀。南沖繩海槽的西界以彎曲的2000公尺等深線為準，此海槽範圍主要在此邊東海大陸斜坡及南方的硫球島弧斜坡之間。宜蘭大陸棚為陸上宜蘭平原向外海的自然延伸。此陸棚呈扇狀，陸棚寬度在蘭陽溪口附近寬約10公里，至頭城及蘇澳附近則變窄為2公里左右。宜蘭大陸棚突出於大陸斜坡之上，實乃大量宜蘭溪帶來的沉積物堆積而成。
宜蘭海脊由宜蘭陸棚向東南延伸形成一個長而窄的地形高區，此海脊分隔了南方的弧前南澳盆地與北面的弧後沖繩海槽。宜蘭海脊以東邊的硫球島弧為界，其區域範圍有限，表現局部性的地形特徵。
東海海水與黑潮水在東海大陸棚坡區交換，而此地區的地形為不規則狀，這種地形效應値得進一步探討其對黑潮邊緣交換過程的影響。

並列摘要

The continental margin off northeastern Taiwan consists of five major physiographic units which are the East China Sea continental shelf, the East China Sea continental slope, the Southern Okinawa Trough, the Ilan continental shelf and the Ilan Ridge. This physiographic framework is provisional and may be revised if better physiographic names are proposed.
The East China Sea continental shelf is relatively wide with a smooth surface marked locally by low-relief features resulting from sea-level fluctuation during the late Pleistocene and by volcanic activities of the back-arc rifting.
The East China Sea continental slope varies laterally in slope gradient and topography. The continental slope is marked is marked by a variety of slumping of sliding scars, erosional gullies, and debris flow deposits of turbidites. The submarine canyons are another prominent topographic feature occurring on the slope. The submarine canyons indent the continental shelf and modify the linear shelf-slope transtition region in to an irregular shape. The western end of the Southern Okinawa Trough has curvelinear bathymetric contours at the maximum depth of about 2,000m. The trough is mainly confined by the continental slope to the north and by sloper off the Ryukyu volcanic islands.