Emerging
Jun 19, 20262
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Kīlauea's 49th Lava Fountaining Episode Marks Ongoing Summit Eruption
Kīlauea's summit has produced 49 lava fountaining episodes over the past year and a half, with episode 50 expected in late June 2026. Scientists classify these repeated cycles of fountaining and pauses as episodes within a single ongoing eruption rather than separate eruptions, because magma remains active in the subsurface between pauses, as evidenced by persistent ground deformation, seismic tremor, and elevated gas emissions.
Quick Facts
Who
USGS Hawaiian Volcano Observatory
What
49 episodes of lava fountaining from Kīlauea's summit
When
Past year and a half
Where
Kīlauea's summit
- 49 episodes of lava fountaining from Kīlauea's summit
- Repeated cycles of spattering, overflows, and fountaining
- Forecasting of episode 50
- Tiltmeter monitoring of deflation and inflation
- Seismic tremor recording
Over the past year and a half, Kīlauea's summit has produced 49 episodes of lava fountaining, with the 50th episode forecast to occur between June 23 and June 27, 2026. The eruption, which began on December 23, 2024, follows a distinctive repeating pattern characterized by precursory spattering and small overflows lasting hours to days, followed by fountaining episodes generally lasting less than 12 hours, and then pauses in surface activity. Despite these pauses, scientists at the USGS Hawaiian Volcano Observatory emphasize that the eruption remains continuous and active.
The distinction between episodes and separate eruptions hinges on the definition of what constitutes an ongoing eruption. By scientific definition, an eruption continues as long as magma remains active and rising in the subsurface, even if surface lava activity temporarily ceases. The Smithsonian Institution's Global Volcanism Program marks the start of a new eruption only after a 90-day pause; Kīlauea's pauses are significantly shorter, ranging from days to weeks. Multiple monitoring systems confirm the eruption's persistence between episodes: tiltmeters record deflation during fountaining as magma is expelled, followed by inflation during pauses as the system repressurizes. Seismic tremor associated with fluid movement remains elevated throughout pauses, and volcanic gas emissions stay consistently high.
Volcanic gas emissions provide particularly strong evidence of ongoing activity. Sulfur dioxide emissions currently range between 1,000 to 5,000 tonnes per day—substantially higher than the pre-eruption baseline of less than 120 tonnes per day. The fountaining originates from one or both persistent vents on the floor of Halemaʻumaʻu crater, with episodes historically lasting between 4.5 hours and over 8 days. Scientists use the repetitive pattern of deflation and inflation recorded by tiltmeters to forecast subsequent episodes based on magma volume erupted and repressurization rates.
This episodic behavior is not unprecedented at Kīlauea. During the middle East Rift Zone eruption at Puʻuʻōʻō in the 1980s, similar episodic fountaining events occurred with longer repose periods, with the longest lasting 65 days. The current summit eruption's shorter pauses and elevated monitoring signals—including ground deformation, seismic tremor, and gas emissions—indicate sustained volcanic activity. While scientists cannot definitively predict how or when this eruption will conclude, the volcano's consistent patterns continue to provide valuable data for forecasting and understanding the ongoing process.
Why This Matters
Understanding Kīlauea's episodic eruption patterns is critical for volcanic hazard assessment, air quality monitoring, and community preparedness in Hawaii. The ability to forecast subsequent fountaining episodes based on magma deflation/inflation cycles and gas emissions data demonstrates how modern volcanological monitoring helps protect residents and infrastructure while advancing our understanding of sustained volcanic activity.