(BIVN) – The ongoing eruption at the summit of Kīlauea within Hawaiʻi Volcanoes National Park remains paused. The anticipated window for the next episode of high lava fountaining has likely been delayed by a short-lived deflationary trend.

USGS Hawaiian Volcano Observatory scientists reported today that the summit deflation that began on Monday reverted to inflation just after 11 a.m. on Tuesday. Inflation continues today. 

“The forecast for the onset of episode 42 lava fountaining has been pushed back to February 14 and 17 based on current models of summit deformation that include the recent deflation,” the Observatory stated on Wednesday. 

USGS: “Electronic Tilt at Kīlauea summit – Past Three Months. The different colored lines show tilt in a specific direction at a specific station (see the legend in upper left corner of each plot). Station UWD is located near Uēkahuna, on the western rim of Kīlauea’s summit caldera. These data are recorded by continuously operating electronic tiltmeter. Positive changes often indicate inflation of the magma storage areas beneath the caldera of Kīlauea, but may also result from heavy rainfall or, occasionally, instrumental malfunctions.” Note the dip, and rebound, on the right side of the graph, plotting the recent deflation at the summit.

From the USGS HVO summit observations posted on February 11th:

Moderate glow was visible at the south and north vents overnight in the webcams, the intensity of the glow was slightly diminished compared to the previous night.

Seismic tremor continued over the past 24 hours and has been relatively steady over the past day. Earthquake activity was low and no earthquakes were located in the summit area during the past 24 hours.

After roughly one day of deflation (just over 2.5 microradians) recorded by the Uēkahuna tiltmeter (UWD), inflation resumed yesterday just after 11 am. Slow inflation continues to be recorded on UWD today. Total inflation in the past day is approximately 1 microradian. Including all inflation and deflation since the end of episode 41, there has now been a net inflation of 25.7 microradians of inflationary tilt since the end of that episode.

The sulfur dioxide (SO2) emission rate from the summit was last measured on February 2 at approximately 5,000 tonnes per day, which at the high end of the typical range of 1,000 to 5,000 tonnes of SO2 per day observed during previous eruptive pauses. This is considerably lower than rates observed during lava fountaining episodes. This morning, webcams show that the plume from the summit vents is being carried to the southwest. The National Weather Service forecast for the Kīlauea summit region for today and tonight indicates north northeast winds at 11-22 mph, with some higher gusts possible.

Rift Zone Observations:

Rates of seismicity and ground deformation remain very low in the East Rift Zone and Southwest Rift Zone. SO2 emissions from the East Rift Zone remain below the detection limit. 

Analysis:

The rapid rebound of inflationary tilt, glow from the vents, and presence of low-level volcanic tremor after episode 41 indicate that another lava fountaining episode is likely. Glow from both vents was present overnight, suggesting magma is high in the column. After a period of significant deflation at the summit, slow inflation resumed yesterday and continues today. The deflation coupled with slow inflation has pushed the modeled forecast window for the likely start of episode 42 fountaining to February 14 to 17. The forecast window may change if the inflation rate picks up or if another deflation event occurs. 

Kīlauea has been erupting episodically since December 23, 2024, primarily from two vents (north and south) in Halemaʻumaʻu. Eruptive episodes, which generally last for less than 12 hours, are separated by pauses that can be as long as over two weeks. 

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.