(BIVN) – The window for the anticipated start of episode 42 in the ongoing eruption of Kīlauea has been delayed once again, as deflation events continue to stall the overall inflationary trend at the summit. 

“There has been no gain in tilt recorded at the summit in the past day,” the USGS Hawaiian Volcano Observatory reported on Saturday morning, as the episodic eruption remains paused. “The forecast for the onset of episode 42 lava fountaining has been adjusted to February 15 through 17, though continued deflation events may delay the episode onset further,” geologists stated. 

USGS graph shows electronic tilt at the Kīlauea Summit (blue line) and East Rift Zone over the past month. Note the fluctuations between inflation and deflation over the last few days.

From the USGS HVO update posted on Saturday:

Summit Observations:

Moderate to strong glow was visible at the south and north vents overnight in the webcams.

Seismic tremor continued over the past 24 hours and has been relatively steady over the past day. Only 2 earthquakes were located in the summit region during the past day.

The Uēkahuna tiltmeter (UWD) has been recording inflation and deflation over the last three days. There was no net gain in inflation during the past 24 hours. The net inflation since the end of episode 41 remains at 28.6 microradians of inflationary tilt.

In recent days, the sulfur dioxide (SO2) emission rate from the summit has varied within the typical range of 1,000 to 5,000 tonnes of SO2 per day, as has been 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 northeast winds at 14-17 mph, with some higher gusts up to 24 mph.

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. Moderate to strong glow from both vents overnight suggests that magma remains high in the column. After a period of summit deflation February 9-10, inflation resumed and persisted until late on the night of February 12. Since then summit tiltmeters have recorded alternating gentle deflation and inflation, but with no net gain or loss of tilt. The current forecast window for the start of episode 42 fountaining is February 15 to 17, but the start is likely contingent upon a return to inflation. If the current deflation continues for a prolonged period of time, the forecast window may change.

Kīlauea has been erupting episodically since December 23, 2024, primarily from two vents (north and south) in Halema‘uma‘u. 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.