外がい輪りん山ざん

noun

outer rim of a crater; somma

Geological term referring to the outer ridge of a volcanic crater or caldera.

• 阿あ蘇そ山ざんの外がい輪りん山ざんは世せ界かい最さい大だい級きゅうのカルデラの一いち部ぶです。

  The outer rim of Mount Aso is part of one of the world's largest calderas.