HVO spokeswoman Janet Babb said preliminary observations show it was not a steam explosion, and there was no water involved. Babb said it was likely a large crater rock wall which collapsed into the lava lake, prompting the explosion.
“We’ve seen this throughout this summit eruption,” she added. “Some have been large and some have been small. This one today was the largest we’ve seen.”
HVO said in a news release earlier this morning that the steady lowering of the lava lake in the crater within Halemaʻumaʻu at the summit of Kilauea has raised the potential for explosive eruptions in the coming weeks.
If the lava column drops to the level of groundwater beneath Kilauea Caldera, influx of water into the conduit could cause steam-driven explosions.
Residents near the area are advised to learn about the hazards of ashfall, stay informed of the status of the volcano and area closures, and review family and business emergency plans.