Mauna Iki, viewed toward the south from the Ka‘ū Desert trail

Mauna Iki, viewed toward the south from the Ka‘ū Desert trail inside Hawai‘i Volcanoes National Park.  Note the very gentle profile, which mimics that of a standard Hawaiian shield volcano.  The distinct dark flow is ‘a‘ā, and its source is a slightly up-raised area of broken pāhoehoe slabs.  Lava must have moved within the shield and accumulated beneath the surface.  By the time it broke out, it had cooled to the point that it could no longer flow as pāhoehoe and instead formed ‘a‘ā.