Episode 13 fountaining began early on March 11 and continued through an HVO helicopter overflight of the Kīlauea summit region around 10:00 a.m. Visibility was slightly hampered by passing showers. The north vent fountain was producing a fast-moving channelized flow that was running along the northern perimeter of the crater (bottom right portion of photo), while the south vent fountain was feeding lava into a wide perched pond (left edge of photo). USGS photo taken by M. Patrick.

On the Halema‘uma‘u crater floor, the front of a fast-moving channelized lava flow from the north vent fountain was composed of slabby pāhoehoe. USGS photo taken on March 11, 2025, by M. Patrick.

During a March 11 Hawaiian Volcano Observatory eruption monitoring flight at Kīlauea summit, scientists landed to make observations and collect samples. At the front of the channelized flow from the episode 13 north vent fountain in Halema‘uma‘u crater, a USGS geologist walks the flow margin to find a safe spot to collect a molten lava sample. All samples are collected in coordination with, and after receiving permission from, Hawai‘i Volcanoes National Park. Analysis of the sample will provide information for ongoing eruption hazard assessment. USGS photo by M. Patrick.

On March 11, HVO geologists observed episode 13 of the ongoing Kīlauea summit eruption from the western caldera rim. Lava fountains from the north vent (left) and south vent (right) were feeding channelized flows across the floor of Halema‘uma‘u crater. USGS photo by M. Patrick.

A telephoto view of the northern vent fountain within Halema‘uma‘u crater. The steep septum separating the north and south fountains was under constant barrage today by molten lava falling from the fountains, with the steep walls on the inside of the cones in a state of constant dripping and flowing back into crater. USGS photo by M. Patrick taken on March 11, 2025.

A USGS geologist uses a handheld laser rangefinder to measure eruption features during the 13th episode of the Kīlauea summit eruption. USGS photo taken on March 11 from the western rim of Halema‘uma‘u by M. Patrick.

The north and south cones on the western edge of Halema‘uma‘u continued degassing on March 12, a day after the end of episode 13 of the ongoing eruption at Kīlauea's summit. Most of the gas consists of water vapor (the primary volcanic gas), with sulfur dioxide (SO2) and other gases. Sulfur dioxide emissions are causing vog downwind of the summit area. When this photo was taken the morning of March 12, the emission rate was approximately 1,300 tons of SO2 per day, similar to other periods between eruptive episodes in the ongoing eruption. During episode 13, parts of south cone (left) were rafted away, resulting in the brown broken surface in front of the cone. The red area surrounded by black lava in the bottom left of the photo is the remnants of the June 2023 eruption cone. USGS photo by N. Deligne.

On March 12, a USGS Hawaiian Volcano Observatory geologist on the southwest rim of Kaluapele (Kīlauea summit caldera) serviced the S2cam webcam. A plume of water vapor and volcanic gas rises from the two vents of the ongoing eruption within Halema‘uma‘u crater, one day after the 13th episode of the eruption. USGS photo by N. Deligne.