Following the seismic swarm and tilt excursion associated with an intrusion over the night of September 30 to October 1, USGS Hawaiian Volcano Observatory staff undertook a helicopter overflight to assess any changes on the upper caldera floor of Kaluapele and the crater floor of Halemaʻumaʻu. The northern part of the caldera floor of Kaluapele hosts numerous cracks that have been present since the 2018 caldera collapse and some have existed for even longer. During the overflight, no new cracks were observed, and significant widening of the already existing cracks was not apparent. USGS phot by D. Downs.

Aerial view of the northern part of the crater floor of Halemaʻumaʻu at the summit of Kīlauea taken during a USGS monitoring overflight on the morning of October 1, 2026. Black rubbly ʻaʻā and smooth gray pāhoehoe lava flows are visible emanating from the vent complex that is visible the left background of the photo. USGS photo by D. Downs. 

Aerial view of part of the fissure system that opened on September 14, 2026, on the northern caldera wall. Parts of this fissure system continued to erupt until September 16. The explosion pit and nearby fissure high on the caldera wall were the shortest-lived parts of this fissure system. Bright yellow patches of sulfur have since accumulated near these vents. USGS photo by D. Downs. 

Aerial view of the north (bottom of the photo), south (upper left), and west (obscured by south vent plume) vents in Halema‘uma‘u at the summit of Kīlauea on the morning of October 1, 2026. All three vents were strongly glowing during the overflight, although glow from the west vent is obscured in this view. Lava in these vents was seen about 100 ft (30 m) down in the vent conduit. USGS photo by D. Downs.