The Okinawa Trough (沖縄トラフ, Okinawa Torafu) (also called Chinese: 中琉界沟, literally China-Ryukyu Border Trough[1] ) is a seabed feature of the East China Sea. It is an active, initial back-arc rifting basin which has formed behind the Ryukyu arc-trench system in the West Pacific. It developed where the Philippine Sea Plate is subducting under the Eurasia Plate.[2]
横渡中琉界沟黑水沟,进入"琉球大洋",乃因此沟以东属琉球海域,以西包括钓鱼台列屿乃属中国海域。