Hawaiian Volcano Update: Kīlauea Intrusion As Vent Complex Overflows Continue - October 1, 2026
Since September 22nd, roughly 200 overflows have spilled from the established vent complex, from only the north vent for 6 days before the south vent contributed its half of the total over the next 2 days. Then yesterday, September 30, ground tremor began to increase around 12PM, before earthquakes and tilt increased beneath the vent system as magma pressure built. Around 8 PM the magma began intruding another crack system within Halemaʻumaʻu, separate from the one which erupted from September 14 to 16, thought to be between the main vents and the northern part of the caldera beneath Kīlauea overlook within Hawaiʻi Volcanoes National Park. At 9:52 PM, a magnitude 3.4 only 1000 feet or 320 meters deep marked the peak of about 80 shallow earthquakes in the summit region over 14 hours. The underground injection of magma continued until 3 AM based on the large, rapid offset on the Uēkahuna tiltmeter, since when the volcano has resumed slowly swelling.
The start of the intrusion quieted the vent complex at first, before the north vent came back to life with vigorous overflows during the later part of the intrusion and the south vent once it was over. Strong glow and spatter persisted throughout from both vents, with the west vent showing occasional glow. According to the USGS Hawaiian Volcano Observatory, “there is no evidence that magma associated with this intrusion erupted in a new location.” Further, “it appears that intrusive activity is complete, although conditions can change rapidly including eruption from a new vent with little or no seismicity or deformation.” They add, “it is not possible to say with certainty that this activity will lead to the onset of another fountain event at this time, although conditions remain favorable. Because the summit system remains active and highly pressurized, the two most likely possibilities are that activity continues at the north-south-west vent complex, or it activates another existing weak crack system in the summit region.” Finally, in this week’s Volcano Watch, they add that “while activity has been confined to the summit region of Kīlauea for nearly the past two years, there is always the possibility that magma could eventually migrate out of the summit region with little to no warning. So far, there are no signs of that, and the USGS-HVO has been constantly monitoring Kīlauea for signs of change.”
Between episodes, the vents continue to emit roughly 1,000 to 5,000 tonnes of SO2 per day, which while low-level compared to the output during fountaining episodes on the order of 200,000 tonnes, is still much greater than industrial standards. Thankfully, Hurricane Nolo had limited impact on Hawaiʻi Island last weekend, and it’s pull of southeast winds across the island is just ending. While trade winds are forecast to return, the continued Pacific storm season is likely to disrupt them again next week, increasing the potential for vog in nearby communities. Both during and between episodes and new outbreaks, vog and tephra remain the most common hazards for island residents, and the usual precautions and preparations apply, especially for those with respiratory sensitivities – more information at https://vog.ivhhn.org/. As usual, we summarize the monitoring signals, imagery, and reports available courtesy of the USGS Hawaiian Volcano Observatory as well as our broader community, annotating the presentation on-screen and discussing live viewer questions as we go.
