noun
ria coastline; deeply indented coastline
A geographical term for a coastline formed by the submergence of river valleys, creating a jagged, deeply indented shoreline. Used in geography and earth science contexts.
三陸海岸は典型的なリアス式海岸として知られている。
The Sanriku Coast is known as a typical ria coastline.
A shorter synonym for リアス式海岸, also meaning ria coastline. リアス式海岸 is the more formal, full term.
From リアス (ria, from Spanish 'ría') + 式 (style/type) + 海岸 (coast). The term 'ria' originates from the Galician word for river mouth, describing drowned river valleys.