Kīlauea unrest continues as HVO forecasts lava fountaining window

Scientists at the U.S. Geological Survey’s Hawaiian Volcano Observatory reported continued unrest beneath Kīlauea’s Halemaʻumaʻu crater and said the summit eruption remained paused but episodic, with the next lava fountaining episode forecast to begin within a Jan. 20–25 window. The forecast, issued in a Jan. 20 update that followed daily advisories on Jan. 17 and Jan. 19, reflects updated inflation models, recent seismicity and visual observations at the summit.

HVO said the summit activity is concentrated beneath Halemaʻumaʻu, located at 19°25'16" N, 155°17'13" W and standing at 4,091 feet elevation (VNUM #332010). Since Dec. 23, 2024, two primary vents in Halemaʻumaʻu—north and south—have produced episodic summit eruptions. Episodes generally last less than 12 hours and are separated by pauses that can exceed two weeks; HVO’s recent messaging referenced episode 40 and the rapid rebound in inflationary tilt that followed it as a principal driver of the current timing estimate.

Seismic swarms beneath the southeast part of Halemaʻumaʻu have accompanied the inflation. HVO recorded an earthquake cluster beginning Jan. 18 at 3:49 PM HST, a second cluster on Jan. 19 at 3:58 AM HST, and continuing sporadic swarm activity on the morning of Jan. 20, with the most recent cluster occurring just after 5:07 AM HST. The observatory characterizes these swarms as related to migrating magmatic pressure within the summit region and cautions that their effect on the onset or character of the next fountaining episode is unknown.

HVO maintains the Volcano Alert Level at WATCH and the Aviation Color Code at ORANGE in its Jan. 17 and Jan. 19 updates. Those designations reflect elevated unrest but not sustained open-vent activity. HVO also reported visible glow from vents and persistent low-level volcanic tremor, metrics incorporated into reinflation models that produced the Jan. 20–25 window. The agency emphasized that model-driven forecasts are subject to revision as new observations arrive; an earlier Jan. 19 advisory had given a slightly narrower Jan. 21–25 window, shifted one day earlier in the Jan. 20 update.

For Hawai‘i’s economy, even short-term summit episodes carry measurable implications. The Aviation Color Code ORANGE prompts heightened monitoring by aviation authorities and can lead airlines to adjust routes or schedules if ash becomes a factor, though HVO has not reported significant ash emissions or activity along Kīlauea’s East Rift Zone or Southwest Rift Zone. Hawaiʻi Volcanoes National Park and the Hawai‘i County Civil Defense Agency remain in active coordination with HVO on visitor access and hazard messaging, which can affect tourism flows—one of the state’s principal economic sectors—on short notice.

HVO posts Observatory Messages, daily updates and formal Volcano Notices on its USGS website and provides live monitoring feeds for seismicity, tilt, gas and visual observations. Officials urge residents and visitors to monitor HVO updates and Hawaiʻi Volcanoes National Park guidance, and to heed civil defense notifications; forecasts may change quickly as the volcano’s behavior evolves.