For ten weeks in the summer of 2018, the floor of Kilauea's summit crater kept falling. Not once, dramatically, the way a movie volcano collapses. Sixty-two separate times, on a rough daily rhythm, each one registering as its own small earthquake, until a crater that had held roughly the same shape for generations was gone, and a much bigger one stood in its place.
That crater is Halema'uma'u, and in Hawaiian tradition it isn't just a hole in a volcano. It's a home. What happened to it in 2018 is a story about geology, but it's also a story about what it means for a sacred place to visibly, physically change while people are still watching it.
The House of the Amau Fern
Long before geologists had instruments to measure it, Native Hawaiians had a name and a story for the pit at Kilauea's summit. Halema'uma'u means, roughly, "house of the amau fern," and in Hawaiian tradition it is the dwelling place of Pele, the akua (deity) associated with fire, lightning, wind, and volcanoes. Offerings are still left at the crater rim today, and the mountain's ongoing activity is, for many, not separate from Pele's presence there but an expression of it.
That context matters for anything written about this crater's geology. The 2018 collapse wasn't just a data point for the U.S. Geological Survey. It was a transformation of a specific, named, sacred place, one that continues to be visited, honored, and watched by people for whom the mountain is not simply scenery.
A Crater That Fell in Stages
The collapse ran alongside a much larger eruption down on Kilauea's lower East Rift Zone, where lava was destroying homes in the Puna District through that same summer. At the summit, magma draining out from beneath Halema'uma'u left the ground above it unsupported, and the crater floor began dropping in discrete steps rather than one continuous slide. Between late May and August 2, 2018, scientists counted 62 separate collapse events, most producing their own magnitude-5-range earthquake felt across the island.
Each collapse looked roughly the same from the instruments: a sudden drop, a jolt, then quiet until the next one. Stacked together over ten weeks, sixty-two of them reshaped the entire summit.
See the New Crater Rim
The rebuilt Crater Rim Trail and overlooks reopened after 2018. The trip planner pairs them with Kilauea Iki in one summit-day loop.
Open the Trip PlannerRoughly Double, By Volume
Before the 2018 event, Halema'uma'u measured roughly 770 by 900 meters, about 2,530 by 2,950 feet, a crater that had looked more or less that way since the last major reshaping decades earlier. The collapses didn't just widen it. They deepened it dramatically: the crater's volume grew from somewhere around 54 to 60 million cubic meters before the summer began to about 885 million cubic meters by the time it ended. Its floor now sits roughly 600 meters, about 2,000 feet, below the surrounding caldera rim, deep enough that the bottom is out of sight from most overlooks.
- Collapse events 62, LATE MAY–AUG 2, 2018
- Pre-2018 footprint ~2,530 × 2,950 FT
- Volume before ~54–60M m³
- Volume after ~885M m³
What's Down There Today
Halema'uma'u didn't just collapse once and go quiet. A pool of water, unprecedented at this summit in modern record, appeared at the bottom of the much-deeper crater in 2019, evidence of just how far below the water table the new floor now sat. Later eruptive activity at the summit has since returned lava to portions of the crater floor, building new material back into the pit even as the mountain keeps a close eye on what 2018 emptied out. The Crater Rim Trail and its overlooks, rebuilt and reopened after the summit closures that followed the collapse, remain the best places to look down into what's there now, keeping a respectful distance from a place that's still, by any account, active.
Facts and figures checked against USGS Hawaiian Volcano Observatory published records of the 2018 Kilauea summit collapse and NPS.gov's materials on Halema'uma'u and Hawaiian cultural tradition.
Sixty-two times that summer, the ground gave a jolt and settled a little lower, until the house Pele was said to keep at the summit had a completely different floor than the one visitors had been looking into for generations. It's still changing today, water pooling where lava once stood, lava returning where the water pooled, which is a strange kind of comfort: whatever Halema'uma'u looks like on the day you visit, it's not finished yet.