Aloha, it's your weekly Volcano Minute, brought to you by the USGS Hawaiian Volcano Observatory.

Today we’re talking about the summit of Kīlauea. While flames, spatter, and lava erupted intermittently from the vents in Halemaʻumaʻu that have been active since December 2024, magma began to carve a new path underground beneath the caldera.

For weeks, Kīlauea’s summit has been highly pressurized—ground deformation and small earthquakes hinted at unrest. In mid-September, six small vents quietly opened along the northwest wall of Halemaʻumaʻu with modest lava flows onto the crater floor.

Then, on September 30th, things started to change again. Around 2 p.m., a swarm of earthquakes shook beneath the vents about a mile below the surface. More than 80 earthquakes shook the summit in total, including a magnitude 3.4 that was felt by dozens of residents.

During the shaking, tiltmeters in the summit region of Kīlauea recorded rapid ground inflation—clear evidence of new or widening cracks as magma intruded underground. The eruption at the vent complex that has been active since December 2024 briefly paused, and then picked back up as the intrusion waned overnight.

By the next morning, October 1rst, USGS Hawaiian Volcano Observatory geologists saw no obvious new cracks on the surface, though the caldera floor is already heavily fractured from the 2018 collapse event. Lava remained visible deep within the north vent, confirming that Kīlauea’s summit is still very pressurized.

So what comes next? A renewed fountaining event is possible, lava could emerge quietly through existing cracks, or magma could intrude new areas altogether. For now, activity remains at the summit, and scientists are continuing to keep a close eye on Kīlauea.

Mahalo for listening, I’m Katie Mulliken and this was your weekly volcano minute brought to you by the USGS Hawaiian Volcano Observatory.