noun
aa lava flow
Geological term for a type of basaltic lava flow with a rough, jagged, clinkery surface. Used in volcanology.
ハワイの火山では、アア溶岩とパホイホイ溶岩の両方が見られる。
Both aa lava and pahoehoe lava can be seen at Hawaiian volcanoes.
Pahoehoe lava has a smooth, ropy surface, contrasting with the rough, blocky texture of aa lava.
From Hawaiian ʻaʻā (rough, stony lava) + Japanese 溶岩 (lava).