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A day after the end of episode 12 of the ongoing eruption at Kīlauea's summit, volcanic gas emissions continue from the recently active north and south cones on the western edge of Halema‘uma‘u. Most of the gas consists of water vapor (the primary volcanic gas), with sulfur dioxide (SO₂) and other gases.

Lava flows from the eruption which started on December 23, 2024, within Halema‘uma‘u at the summit of Kīlauea volcano, have buried most of the cone from the June 2023 eruption, seen here in the upper middle of photo. This telephoto was taken north of the degassing north and south cones, and is looking toward to the south through the volcanic gas plume.

USGS Hawaiian Volcano Observatory (HVO) collects tephra from lava fountaining in buckets. Each bucket has a weight inside to prevent high winds from blowing the bucket away; some of these weights are milk jugs filled with sand.

A view across of the new lava flows on the floor of Halemaʻumaʻu, looking towards the active north and south vents on the west wall of the crater. USGS photo by D. Downs on March 5, 2025.

A telephoto image of episode 12's lava fountains show the varied textures of motel material as it leaves the vent. In the fountain you can see the formation of both cinder and spatter. Cinders are glassy, vesicular, pyroclastic fragments that fall to the ground in an essentially solid condition. These are the smaller, darker particles in the figure.

During the lava fountains of episode 12, which reached approximately 300 feet (90 meters) high, tephra particles traveled through the air to be deposited on the crater rim down wind. This clast was about 16 inches (40 centimeters) long. The tephra clasts formed during the recent lava fountains are very bubble rich and delicate, breaking easily when they are moved.

With permission from Hawaiʻi Volcanoes National Park, USGS-Hawaiian Volcano Observatory staff geologists conducted a monitoring overflight of Kīlauea summit eruption area at approximately 10 a.m. HST on March 5, 2025. During the flight, the team landed briefly on the floor of Halemaʻumaʻu to collect a molten sample of lava.

During a USGS Hawaiian Volcano Observatory Kīlauea eruption monitoring overflight on March 4, 2025, geology field crews sampled a viscous molten lava flow on the eastern margin of the lake. This flow is likely an ooze out from the molten lake interior, and represents lava erupted in previous episodes.

A USGS Hawaiian Volcano Observatory scientist monitors episode 12 of the ongoing Kīlauea eruption during the evening of March 4, 2025. While working in the hazardous closed area of Hawaiʻi Volcanoes National Park, USGS staff wear personal protective equipment, including high-visibility clothing, hard helmets, gas masks, gloves, and eye protection. USGS photo by M.

Episode 12 of the ongoing Halemaʻumaʻu eruption began a fountaining phase at 2 p.m. HST on March 4.  Several small lava flows came from the south vent during the morning and early afternoon of March 4. At 2:00 p.m. HST, fountaining began at the north vent.

Both the north and south vents have been active in the ongoing episode 12 of the Kīlauea summit eruption in Halemaʻumaʻu. Lava fountains feed lava flows that cover part of the floor of Halemaʻumaʻu. USGS photo by L. Gallant.

Coincident with a scheduled USGS Hawaiian Volcano Observatory eruption monitoring overflight the morning of Tuesday, March 4, 2025, Kīlauea's ongoing eruption in Halema‘uma‘u started to show minor activity at both eruptive vents. This aerial view of the vents taken at 8:04 a.m.

A panoramic view of Kaluapele, the caldera at the summit of Kīlauea volcano, taken from the Volcano House Hotel overlook in Hawaiʻi Volcanoes National Park. The intermittently active vents on the west wall of the caldera are visibly degassing in the shadowed background of the image, while Mauna Loa is illuminated in the sunlight.

Only weak vent activity was observed on the USGS Hawaiian Volcano Observatory monitoring helicopter overflight of Kīlauea summit at 8 a.m. HST on March 4, 2025. Weak effusive activity continued throughout the day until around 2 p.m., when fountaining started with more vigor, producing a larger flow across the crater floor. USGS photo by M. Patrick.

A USGS Hawaiian Volcano Observatory geologist collected of molten sample of lava in the eastern portion of Halema‘uma‘u crater the morning of March 4, 2025. In this portion of the crater, far from the eruptive vents, lava has slowly oozed out in recent days as residue from earlier episodes.

During the early evening of March 4, 2025, USGS scientists captured this view of both the north and south vent erupting lava fountains during episode 12 of the ongoing Kīlauea summit eruption. During this episode, lava fountains reached up to 250-300 feet (80-90 meters) in height. USGS photo by M. Patrick. 

This view of episode 12 of the Kīlauea summit eruption in Halemaʻumaʻu was taken the evening of March 4, 2025, from the Kaluapele overlook near Kīlauea Military Camp in Hawaiʻi Volcanoes National Park. USGS photo by K. Mulliken.

Hawaiian Volcano Observatory geologists visited the caldera rim at Kīlauea this morning and observed the end of the summit eruption's eleventh episode, as fountains shut down at both eruptive vents between approximately 6:30 and 7:00 am.

The density of clasts produced by recent fountaining at the summit of Kīlauea is similar to that of a kitchen sponge, due to abundant gas bubbles. These bubbles range in size from ones too small to see, up to larger ones about the size of golf balls. USGS photo by M. Patrick.

A Hawaiian Volcano Observatory geologist uses a laser rangefinder to measure the evolving height of cinder cones produced by recent lava fountaining at the summit of Kīlauea. Today, February 26, the highest part of the tallest cone rim was about 160 feet (48 meters) above the crater floor. USGS photo by M. Patrick.

A Hawaiian Volcano Observatory geologist measures the chemistry of volcanic gases emitted by Kīlauea summit eruption episode 11—within Halemaʻumaʻu crater—on February 26, 2025. USGS photo by M. Patrick.