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.

A USGS Hawaiian Volcano Observatory geologist uses a handheld laser rangefinder on the southwest rim of Kaluapele (Kīlauea summit caldera) to measure the height of the recently active cones within Halema‘uma‘u. USGS photo taken on March 12, 2025, by M. Patrick.

A closeup view of the south cone at the summit of Kīlauea, showing the semi-molten nature of the cone flanks. During fountaining, lava accumulates on the cone's flanks at such a high rate that the material remains hot and semi-molten, despite the appearance of cooled, solid material on the surface. On the steep slopes of the cone, this semi-molten material can then reach a critical thickness and begin flowing downhill, in a kind of secondary lava flow. During the Pu‘u‘ō‘ō eruption, these flows were called agglutinated spatter flows, or rootless spatter flows. Several zones of striations on the cone also show where large chunks separated and slid downwards, leaving grooves in the flank. USGS photo by M. Patrick.

The section of Crater Rim Drive downwind of the recent fountaining, and in an area closed to the public due to volcanic hazards, has been covered by numerous layers of tephra in the past several months. The tire tracks are centered over the Crater Rim Drive roadway, where USGS scientists access critical volcano monitoring sites. The tip of a shovel touches the original asphalt surface. Here, the tephra deposit is 20 inches (50 cm) thick. A blue haze from the volcanic gas plume is visible in the background. USGS photo by M. Patrick.

An orange five-gallon plastic bucket, secured by heavy weights, was one of several used to collect tephra from the ongoing lava fountaining at the summit of Kīlauea. The episode 13 fountaining, however, cast large bombs (some of them molten) in this particular area, battering the ground. Although aluminum tubs will be used in this area in the future, the damaged bucket did collect a serviceable tephra sample. Analysis of tephra samples will provide information for ongoing eruption hazard assessment. USGS photo taken by M. Patrick.

An HVO geologist returns from a tephra collection bucket at the summit of Kīlauea, carrying a new sample. The outgassing plume from the vents is carried over the roadway, now covered by over 50 cm (20 inches) of tephra in places. All samples are collected in coordination with, and after receiving permission from, Hawai‘i Volcanoes National Park. USGS photo by M. Patrick.