(BIVN) - With the next episode of lava fountaining at the summit of Kīlauea volcano expected at any time, scientists with the USGS Hawaiian Volcano Observatory write about the increasing airborne hazards associated with the activity, and why its prompting a change in their alert notifications.
From the latest Volcano Watch article, written by USGS HVO scientists and affiliates:
Episode 23 of Kīlauea's ongoing eruption within Halemaʻumaʻu occurred on Sunday, May 25, 2025. Record-setting lava fountain and plume heights were reached quickly for this eruption, less than one hour after episode 23 started. Given the increasing airborne volcanic hazards associated with this eruption, the USGS Hawaiian Volcano Observatory will change episode notification types moving forward.
Episode 23 lava fountains erupted continuously for six hours and reached heights of about 1,150 feet (350 meters). These were the highest lava fountains observed so far during the current eruption, which began on December 23, 2024. An impressive blanket of tephra -- volcanic rock fragments carried into the air -- was deposited beneath and downwind of these fountains, primarily in the upper part of Kīlauea's Southwest Rift Zone in the closed area of Hawaiʻi Volcanoes National Park.
This episode also had the highest gas plume seen thus far in this eruption sequence. The plume reached heights of more than 20,000 feet (6,100 meters) -- and likely over 25,000 feet (7,600 meters) -- above Kīlauea's summit, which is at an elevation of about 4,000 feet (1,200 meters) above sea level. The plume contained high levels of water vapor (H2O), carbon dioxide (CO2), and sulfur dioxide (SO2).
These record-setting fountain and plume heights were reached quickly, less than one hour after episode 23 started. Following an extended period of gradual inflation and precursory low-level activity, episode 23 began at 4:15 p.m. with thin jets of lava erupting from the north vent. Fountaining became more vigorous around 4:25 and then escalated quickly and dramatically around 4:36 p.m. as tremor intensified and gradual inflation switched to rapid deflation. North vent fountains approached 1,000 feet (300 meters) in height by 5:00 p.m. and peaked just after 5:30 p.m. South vent fountaining began at 5:20 p.m. and reached heights of 600-800 feet (180-250 meters) by 6:30 p.m. that were sustained until the final hour of the episode.
Episode 24 will likely begin within the coming week. Kīlauea's summit is currently reinflating and magma remains close to the surface within the north and south vent conduits. During a helicopter overflight on May 28, USGS Hawaiian Volcano Observatory (HVO) scientists could see lava churning away at a depth of a few tens of yards (meters) within the north vent conduit. Strong orange glow from the vents is visible at night on HVO webcams and from public viewing areas in Hawai'i Volcanoes National Park.