Submarine Valley

Japanese: submarine valley（英語表記）submarinevalley

…Shelf channels, which cut shallowly into the continental shelf, are drowned valleys formed by the erosion of rivers and glaciers. There are two types of valleys on the continental slope: submarine canyons, which have steep walls and are narrow V-shaped, and submarine valleys, which are wide U-shaped. The former meander somewhat and gather branching valleys to reach the deep sea plain or ocean floor. …

From [Submarine Topography]

… trench—A long, narrow, especially very deep, and asymmetrical depression in the ocean floor, with relatively steep slopes. valley — A relatively shallow, wide depression, the floor of which usually exhibits a continuous slope. The term is not generally used for landforms that have canyon-like features throughout most of the landform. …

*Some of the terminology that mentions "Submarine Valley" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…大陸棚を浅く刻む陸棚谷shelf channelは河川や氷河の浸食した谷が沈水した溺れ谷である。大陸斜面上の谷には，谷壁が急で幅の狭いV字谷submarine canyon(狭義の海底谷)と幅の広いU字谷submarine valley(海谷)とがある。前者は多少蛇行しつつ樹枝状の支谷を集め深海平たん面や大洋底に達する。…