Volcano Minute — Kīlauea summit eruptions outside of Halemaʻumaʻu

Aloha, it's your weekly Volcano Minute, brought to you by the USGS Hawaiian Volcano Observatory. 

Today, we’re looking at a part of Kīlauea’s story that many visitors — and even many locals — don’t realize: summit eruptions don’t always stay inside Halemaʻumaʻu. 

Halemaʻumaʻu crater sits within Kaluapele, the larger summit caldera that usually contains Kīlauea’s eruptions. In recent decades, activity has indeed been focused in Halemaʻumaʻu — from the decade‑long lava lake that drained during the 2018 collapse, to the brief water lake, to the many eruptions we’ve seen since 2020, including the fountaining episodes over the past year and a half. But historically, Kīlauea has erupted outside the modern caldera many times. 

Some of the earliest written accounts of summit eruptions beyond Halemaʻumaʻu come from 1832 and 1868. The best‑known example is the spectacular 1959 Kīlauea Iki eruption, which built the cone Puʻupuaʻi just east of the caldera. 

More eruptions followed on the south side of the caldera — in 1971, 1974, and 1982 — with lava spilling over the rim and even reaching areas of the caldera floor below Volcano House Hotel. Visitors to the Keanakākoʻi overlook today can still see remnants of those eruption fissures, though portions were lowered during the 2018 collapse and partly buried by recent lava flows. 

These past events remind us that future Kīlauea summit eruptions could also occur outside Halemaʻumaʻu. Recent shallow earthquakes and ground deformation along the south rim aren’t signs of an imminent eruption, but they do highlight how dynamic and changeable Kīlauea’s summit can be. 

Mahalo for listening, I’m Katie Mulliken and this was your weekly volcano minute brought to you by the USGS Hawaiian Volcano Observatory.