U.S. Geological Survey Hawaiian Volcano Observatory (HVO) scientists are actively studying ancient tephra and lava flow exposures within Kīlauea's Kaluapele, revealed by the dramatic 2018 summit collapse. These newly accessible layers offer unprecedented insights into the volcano's long-term eruptive history, which has largely been obscured by younger lava flows.
Kīlauea's frequent activity means most of its surface is covered by lava less than 1,000 years old, making older eruption data scarce, especially at the summit. However, the 2018 summit caldera collapse, a "hulihia" or dramatic change, created a 1640-foot (500-meter) deep crater, exposing sections of tephra and lava flows unseen since HVO's founding in 1912. These exposures preserve deposits from some of the oldest eruptions ever cataloged near Kīlauea’s summit.
Since 2023, HVO geologists have undertaken missions to sample these layers. Initial efforts focused on the deepest tephra exposure, which has since been re-buried by subsequent lava flows. More recently, in July 2026, during a pause between lava fountaining episodes 50 and 51, geologists accessed a second significant tephra section about 20 feet (6 meters) above the caldera floor. They described and sampled the layers before episode 51 and 52 again buried the exposure.
The visited tephra exposures from 2023 and 2026 are believed to be much older than the 1-2 thousand-year-old Uēkahuna Ash, potentially representing previously unstudied eruptions. Analysis of these samples will help determine their eruption times and mechanisms, shedding light on a previously murky period of Kīlauea’s evolution. HVO continues to monitor Kīlauea, which has been erupting episodically since December 23, 2024, currently at an ADVISORY alert level, with episode 54 occurring on August 25.