September 19, 2025 – Precursory activity at Halema‘uma‘u before episode 33

Activity at the Halema‘uma‘u summit eruption is increasing prior to episode 33. North vent is experiencing gas pistoning cycles (lava fills vent, overflows, drains). Lava flows from north vent are contained to a single dominant channel exiting the cone. North vent is approximately 20 m (65 feet) from base of the vent to the perched lava pond. Activity continues in this cycle at this time with low level dome fountains approximately 3-5 m (10-15 feet) high. USGS photo by H. Winslow.