11th episode of eruptive activity at Kīlauea summit ends after nearly 13 intense hours

Episode 11 was one of the briefest eruptive periods of the ongoing summit eruption of Kīlauea volcano on the Big Island since it started Dec. 23, 2024, but its brevity was no reflection of its might.

Throughout its 12 hours and 44 minutes before ending at 7:06 a.m. Wednesday, the most recent episode of the eruption lit up the skies over Puna with a bright, eerie reddish-orange glow seen by people from throughout Puna, with comments and photos posted across social media by residents of communities including ʻĀinaloa, Glenwood, Hawaiian Paradise Park, Pāhoa and Mountain View.

Even from as far away as Kalapana Seaview Estates on the Big Island’s southeast coast in lower Puna, just more than 23 miles from Hawaiʻi Volcanoes National Park, the home of Kaluapele, the volcano’s summit caldera.

Episode 11 was so intense that people could hear the fountaining vents in the southwest portion of Halemaʻumaʻu Crater degassing from miles away.

One Facebook user said it sounded crazy already nearly 11 miles away in Fern Forest just about an hour after the fountaining began at 6:22 p.m. Tuesday. Another replied it was “super loud in Mauna Loa Estates” just less than 3 miles from the summit.

Yvonne Bauer, who has journaled her experiences observing this eruption of Kīlauea and has seen all 11 episodes, wrote in a Wednesday morning post in the Hawaiʻi Tracker Facebook group that the sound reminded her of several fighter jets just starting simultaneously.

“The ground trembled, and the air was filled with a roar!!” exclaimed Bauer in her post, adding in a reply to another post that it was one of the loudest degassing episodes she’s heard, calling it wild to experience it while standing on the crater rim. “This was Pele; her appearance was expected, but it was the most mesmerizing thing when she came to visit.”

Episode 11 also produced some of the highest lava fountains of the Halemaʻumaʻu eruption so far, with a geyser of molten rock skyrocketing up to 600 feet above the vents within 1 to 2 hours after the eruptive activity started.

Bauer reporting that at one point it reached the crater rim and above.

“What a show it was,” she wrote. “I walked towards Kilauea Overlook and took some shots from the rim nearby. I always wanted to know if the fountain would go taller than the bluff. And it did, for sure!!”

Lava flows from Episode 11 covered about 75% to 80% of the Halemaʻumaʻu crater floor and sent lava onto the downdropped block around the September 2023 vents.

Large amounts of pumice, Peleʻs hair and lighweight reticulite were deposited on the west rim of Halemaʻumaʻu overnight Tuesday into Wednesday, blanketing the area. A few lightweight “ribbon” bombs up to about 1 to 2 feet were also found on top of the pumice.

Both vents continued to degas Wednesday morning.

The north vent began erupting at 6:22 p.m. Tuesday night with low fountains that during the next hour grew in height to about 600 feet.

Small spatter fountains began at the south vent just before 7 p.m. and by 8 p.m. were producing small flows. The south vent fountains and flows increased in size by 9 p.m.

Both vents continued fountaining together until 6:35 a.m. Wednesday when fountaining stopped at the north vent.

South vent fountains began to drop at the same time, and by 7:06 a.m. lava fountaining and flows stopped, marking the end of Episode 11.

High levels of volcanic gas — primarily water vapor, carbon dioxide and especially sulfur dioxide — continue to be the primary hazard of concern since it can have far-reaching effects downwind.

As sulfur dioxide is continuously released from the summit during an eruption, it reacts in the atmosphere to create the visible haze known as vog, or volcanic smog, downwind of Kīlauea.

Volcanic gas emissions remain elevated.

Based on measurements during earlier fountaining episodes and pauses during this summit eruption, sulfur dioxide emission rates are likely to be about 1,000 tonnes per day during the current pause. A sulfur dioxide emission rate of 2,100 tonnes per day was measured at 11 a.m. Feb. 20.

Additional hazards include Pele’s hair and other volcanic fragments.

Pele’s hair — strands of volcanic glass often produced by lava fountaining activity that can cluster and tangle together, appearing like tumbleweed — can be wafted downwind to greater distances, depending on fountaining activity and wind conditions once the volcanic glass fragments are on the ground.

Strands Pele’s hair have been reported on surfaces throughout the Kīlauea summit area within Hawai‘i Volcanoes National Park and surrounding communities.

The onset of the most recent eruptive activity was preceded by the appearance of glow along the row of September 2023 vents on the east side of Halemaʻumaʻu, which began at one cone the evening of Feb. 24 and became visible along the entire 2023 fissure at about 6 p.m. Wednesday and remained persistent through much of the night.

This suggests magma within the vent system might have intruded into the molten interior of Halemaʻumaʻu Crater prior to the onset of Episode 11.

Similar glow was not observed along the 2023 vents prior to or during Episode 10 of the ongoing summit eruption.

Summit tilt changed rapidly from inflation to deflation at the onset of this episode of eruptive activity and dropped about 10 microradians during fountaining.

Tilt switched back to inflation at 6:35 a.m. Wednesday when fountaining stopped at the north vent.

Seismic tremor increased rapidly at the onset of Episode 11, decreased sharply when north vent fountaining ceased and returned to high background levels when fountaining at the south vent stopped a half-hour later.

The Uēkahuna tiltmeter at the summit recorded less than 0.5 microradians of inflation since the end of Episode 11 by the time of Hawaiian Volcano Observatory’s report just before 9 a.m. Wednesday.

Hawaiian Volcano Observatory has been analyzing inflationary tilt patterns prior to the onset of each fountaining episode to estimate the probability of the time window for the onset of a new eruptive period based on minimum inflation necessary to start a new episode and rate of inflation.

Unfortunately, there has not been enough time since the end of Episode 11 to establish if and when another episode is most likely to begin.

The episodic fountaining nature of this summit eruption has not been seen in any of the other Halemaʻumaʻu eruptions since 2020.

Each of the 11 eruptive episodes have lasted from between about 13 hours to more than a week, with the first 10 pauses in activity marked by an immediate change from deflation to inflation as the magma chamber began to recharge and repressurize.

Pauses in eruptive activity have typically lasted from less than 24 hours to 12 days.

Kīlauea’s Volcano Alert Level and Aviation Color Code remain at Watch and Oragne, respectively. The summit eruption is occurring within a closed area of Hawai‘i Volcanoes National Park.

No significant activity has been noted along Kīlauea’s East Rift Zone or Southwest Rift Zone. Rates of seismicity and ground deformation remain very low in both rift zones, with no significant earthquake activity during the past 24 hours.

Hawaiian Volcano Observatory continues to closely monitor Kīlauea and is in contact with the national park and Hawai‘i County Civil Defense about eruptive hazards.

Visit the Hawaiʻi Volcanoes National Park website for visitor information.

“Iʻm still completely blown away from episode 11 … the sounds and sights are still in my mind, and Iʻm pretty sure everyone who could see it will feel the same way,” Bauer wrote in her post.