(BIVN) – Episode 23 in the ongoing eruption of Kīlauea volcano is still stuck in the “precursory” phase, although scientists say activity has increased since Saturday morning. 

The USGS Hawaiian Volcano Observatory reports slow summit inflation has resumed, and “sustained fountaining could begin any time today or tomorrow.” 

“The notable decrease in the rate of summit inflation between Wednesday and Friday has likely delayed the onset of sustained fountaining compared to previous episodes,” the USGS HVO wrote. 

USGS: “On May 22, 2025, USGS Hawaiian Volcano Observatory (HVO) staff stabilized the new V3cam livestream camera. The camera was installed just last week and views since then were shaky due to the strong winds which are common in the caldera. The camera was moved from a tall mast to a more stable tripod setup. As HVO staff conducted this work, loud episodes of gas and ash jetting were happening every 6 minutes at the south vent within Halema‘uma‘u.” (USGS photo by M. Patrick)

From the USGS HVO update posted Sunday morning:

Summit Observations:

Strong glow and periodic vigorous spattering was visible in both vents yesterday and overnight. Minor fountaining up to 20 meters (65 feet) occurred in the north vent after midday yesterday and was accompanied by spillover of lava onto the crater floor. A similar event occurred overnight, also in the north vent. This is similar to activity seen in the lead up to previous sustained fountaining episodes. Precursory activity is expected to increase before the onset of sustained fountains; however, there is no way to estimate the duration of this activity.

Summit inflation has resumed, albeit slowly, with tiltmeters at Uēkahuna (UWD) and Sandhill (SDH) recording over 1 microradian of inflation since yesterday morning. The UWD tiltmeter has recorded a total of approximately 11 microradians of inflationary tilt since the end of episode 22 on May 16. Low level tremor continues beneath Halemaʻumaʻu crater.

The average sulfur dioxide (SO2) emission rate remains around 1,200 tonnes per day (t/d), similar to rates recorded during prior pauses.

The USGS Volcano Alert Level for Kīlauea remains at WATCH.