(BIVN) – The ongoing eruption at the summit of Kīlauea is paused, although scientists calculate the next episode of sustained fountaining will begin later this week.

“The fountaining phase of episode 26 will likely begin between June 18 and 20, 2025, based on current rates of summit inflation,” the USGS Hawaiian Volcano Observatory wrote in a Monday update. “This window is subject to change depending on changes in the rate of inflationary tilt.”

“The fountaining phase could be preceded by hours to days of precursory gas-pistoning activity,” the USGS HVO said.

USGS webcam shows the Kīlauea summit vents on Tuesday morning

From the USGS HVO on Monday:

Overnight, incandescence at both the north and south vents in Halemaʻumaʻu was visible in the V3cam. Degassing also continues from both the north and south vents.

The average sulfur dioxide (SO2) emission rate during inter-episode pauses, such as the ongoing pause, is typically around 1,200 tonnes per day (t/d).

Summit tiltmeters have continued to record inflationary tilt following the end of episode 25. A tiltmeter near Uēkahuna (UWD) has recovered about 10 microradians of inflationary tilt since the end of episode 25.

USGS: “This reference map depicts the Kīlauea summit eruption within Halema‘uma‘u crater that began on December 23, 2024. As of this posting on June 13, the eruption continues episodically. Most of the map data included here were collected during a Hawaiian Volcano Observatory helicopter overflight on June 10, between episodes 24 and 25; for this reason, the provided statistics only reflect the first twenty-four episodes of the eruption.”

Analysis: 

Tiltmeter UWD, near Uēkahuna, has recovered about 10 microradians of inflationary tilt since the end of episode 25 and a tiltmeter near Sandhill (SDH) has recovered 7.5 microradians. As a result, the forecast window for the start of episode 26 fountaining is currently between Wednesday, June 18 and Friday, June 20. This window is subject to change depending on changes in the rate of inflationary tilt. The fountaining phase of past episodes has been preceded by hours to days of gas-pistoning activity, which could also occur prior to episode 26. During gas-pistoning events, gas accumulation causes lava to intermittently rise within one or both vents, with resulting spattering and lava flows onto the crater floor.

The current eruption has been characterized by episodic fountaining not seen in any eruptions since the 1983–86 episodic fountains at the beginning of the Puʻuʻōʻō eruption. Fountains and lava flows have erupted from two vents within Halema’um’a’u crater that we refer to as the north vent and south vent. Each of the previous fountaining episodes lasted from a few hours to over a week and have been accompanied by strong deflation of the summit region. Pauses between the fountaining episodes have been marked by an immediate change from deflation to inflation as the magma chamber recharges and repressurizes. Lava fountaining episodes have occurred approximately once per week since the start of the eruption.

HVO continues to closely monitor Kīlauea and is in contact with Hawai‘i Volcanoes National Park and the Hawai‘i County Civil Defense Agency about eruptive hazards.