(BIVN) – Earthquake swarms continue beneath the summit of Kīlauea, as the Hawaiʻi island volcano slowly builds towards another eruptive episode. 

The ongoing eruption at Halemaʻumaʻu is currently paused. The USGS Hawaiian Volcano Observatory reports another earthquake cluster occurred on Tuesday afternoon. The swarm was accompanied by .4 microrads of deflation. 

The forecast for the onset of the next lava fountaining episode is between January 23 and January 26, geologists estimate, based on current inflation models. 

From the USGS HVO update published on Wednesday morning:

Summit Observations:

Overnight webcam views showed consistent strong glow from north vent and intermittent glow from south vent. Constant low-level tremor continues this morning.

Earthquake swarm activity continued with one cluster yesterday afternoon starting at shortly before 5 PM HST. Locations continue to be spread fairly widely beneath the southeast part of Halemaʻumaʻu. The swarms are related to migrating magmatic pressure within the summit region but their impact on the next episode of fountaining, if any, is unknown at this time. For more information see prior Daily Updates and this Information Statement for more details: USGS Volcano Notice – DOI-USGS-HVO-2026-01-15T06:34:34+00:00

Since the end of episode 40, the UWD tiltmeter has recorded 14.4 microradians of inflationary tilt, with net 1.0 microradians of inflation within the past 24 hours. The late afternoon earthquake swarm was accompanied by -0.4 microrads of deflation, with inflationary trends resuming around midnight. Past pauses in inflationary tilt have resulted in a delay in the onset of the following fountaining episode.

The summit SO2 emission rate was last measured on January 14, at 1,550 tonnes per day, which is within 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 fountaining episodes.

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 40 indicate that another lava fountaining episode is likely. Deflationary tilt accompanying yesterday’s earthquake swarm may have delayed the onset of episode 41, such that the next fountaining episode is likely to occur between January 23 and 26. This forecast is subject to change, however, depending on changes in behavior of the volcano.

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.

The USGS Volcano Alert Level for Kīlauea remains at WATCH.