noun
submerged shoreline; submergent coastline
Technical term in geography and coastal geology. Refers to a coastline formed by land subsidence or sea-level rise, resulting in features like rias and fjords.
リアス式海岸は沈降海岸の一種である。
Ria coastlines are a type of submerged shoreline.
隆起海岸 is an emerged coastline formed by land uplift or sea-level fall, the opposite of 沈降海岸.
Compound of 沈降 (subsidence) + 海岸 (coast). The exact historical derivation is uncertain; the term is a modern technical coinage.