Though difficult to photograph, aerial views showed that this open ...

Though difficult to photograph, aerial views showed that this open vent was but a small window into a large, hot cavity beneath Pu‘u ‘Ō‘ō's northeast flank. Inside, streams of lava from an unseen source (or sources) closer to the crater rim (visible at lower right) were cascading toward the upper left into unknown depths. This view, looking almost straight down, shows the surface of one of these lava streams through the open vent. The ground around this entire area is sunken, corroded, and unstable, and may someday collapse to form a pit.