Hawaiian Volcano Update: Kīlauea Summit Eruption’s Episode 35, Pohoiki Dredge Filled In - October 23, 2025
Precursory intermittent lava overflows to episode 35 began at 7:35 AM last Thursday, October 16, followed by continuous activity almost 36 hours later at 7:28 PM on Friday, then by vigorous fountaining shortly thereafter from the north vent at 8:05 PM and from the south vent at 8:30 PM. Similar to the previous episode, the combined output rate from both vents was roughly double that of Kīlauea’s first 33 episodes, and again produced record high fountains for this ongoing summit eruption. According to the USGS-HVO, “by 10:15 PM, south vent fountains reached heights of nearly 1,500 feet (460 meters) and north vent fountains reached heights of about 1,100 feet (330 meters). These were the highest single fountain and highest pair of fountains seen during this eruption so far.”
On the 300th day of the eruption, this 7.5 hour episode, ending at 3:32 AM on October 18, followed the longest pause thus far of 16.5 days between vigorous fountains. Monitoring signals showing recharge and renewed inflation of Kīlauea summit along with glow and seismic tremor from the vents suggest another episode is probable, with preliminary USGS-HVO models indicating a likely window from November 2 to 10 based on the current data, and subject to change.
Although the massive emissions of volcanic gas were largely, though not entirely, dispersed upwards and away from nearby communities by favorable winds, there was considerable fallout of tephra on Highway 11 up to 9.3 miles (15 km) to the southwest, with some blocks as large as watermelons documented by passing motorists closer to the summit. Atmospheric conditions allowed eruption glow to be visible widely on the east side of the Big Island, along with a rare “light pillar” similar to other documented events at other eruptions worldwide (including Maunaloa in 2022). Since the end of episode 35, gas emissions have returned to the lower, but still significant range of 1,200 to 1,500 tonnes of sulfur dioxide per day. The usual precautions and preparations apply, especially for those with respiratory sensitivities – more information at https://vog.ivhhn.org/.
On the Puna coast, the dredging project at Pohoiki bay completed this past week, and within a matter of days the significant remaining sediment was apparently remobilized by the ocean to block the new channel. Disappointment and frustration is evident in the local community, despite the predominant expectation of this result among experts ever since the gubernatorial veto of the project design that received community input and support (removing all of the sediment) and its replacement with this lower-budget half-measure. We spend some time on this topic again this week, given our history and involvement with this project, the now obvious results, and the increased media coverage. As a result, we will again postpone for another week our review of the patterns of Kīlauea’s episodes which we were unable to present last week due to technical difficulties.
All eruptive activity has been confined to Kīlauea’s summit caldera within Hawaiʻi Volcanoes National Park, with no increased lava threat to people. There continue to be no significant changes on either of Kīlauea’s rift zones. Maunaloa continues to inflate its established post-eruption pattern, including a very slight uptick in earthquakes in recent months. As usual, we summarize the monitoring signals, imagery, and reports available courtesy of the USGS Hawaiian Volcano Observatory, annotating the presentation on screen as we go and discussing live viewer questions.
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