Images

USGS Hawaiian Volcano Observatory geologists observed the fountain activity and monitored changing fountain heights during episode 15 of the Halema‘uma‘u eruption. This photo was taken at 1:00 p.m. HST on March 26 during the high fountain stage of the episode. Photo direction is looking south. Fountain heights reached up to about 750 feet (230 meters) at this time.

Lava fountain activity during episode 15 of the Halema‘uma‘u eruption at the summit of Kīlauea. Fountain heights reached up to about 1,000 feet (305 meters) during episode 15. Vigorous lava fountaining feeds lava flows on the floor of Halemaʻumaʻu crater.  USGS photo by C. Gansecki. 

A USGS Hawaiian Volcano Observatory geologist takes measurements of the fountain heights during episode 15 of the Kīlauea summit eruption in Halema‘uma‘u. This photo, looking south, was taken at around 10:41 a.m. HST on March 26, during the beginning stages of the high fountains. Fountains from the south vent reached over the top of the crater wall at this time.

During the cyclic low fountain to drainback phase of episode 15, both the north and south vents were active. This low-level activity began March 25 around 9:30 a.m. HST and continued for just over 24 hours before the fountaining phase began. USGS photo by H Winslow.

Lava fountain activity during episode 15 of the Halema‘uma‘u eruption at the summit of Kīlauea. Fountain heights reached up to about 1,000 feet (305 meters) during episode 15. USGS photo by C. Gansecki. 

On March 26, 2025, during the early stages of episode 15 of the Halema‘uma‘u eruption, the north vent exhibited cyclic low fountaining and drainback. Here, the lava lake is at its peak overflowing into lava flows at 8:15 a.m. HST, before draining once again. USGS photo by H Winslow.

Lava fountain activity during episode 15 of the Halema‘uma‘u eruption at the summit of Kīlauea. Fountain heights reached up to about 1,000 feet (305 meters) during episode 15. USGS photo by C. Gansecki. 

On March 25, 2025, the north vent within Halema‘uma‘u crater periodically hosted low-level dome fountains during periods of cyclic lava effusion and drainback. This activity characterized the early stages of episode 15 in Kīlauea's ongoing summit eruption. USGS photo by M. Zoeller.

Radar interferograms showing examples of linear subsidence features (indicated by yellow arrows) that occurred directly above recent dike intrusions.

An early morning overflight on March 21 allowed HVO geologists to conduct a new photo survey of the crater floor to measure the volume of erupted material from the latest fountaining episode. Fountaining ended yesterday, March 20, and this morning only a degassing plume was exiting the vents. USGS photo by M. Patrick.
 

The vent craters within Halema‘uma‘u were mostly obscured by the thick degassing plume the morning of March 21, but there were fleeting views of incandescence in the north crater. This photo shows what appeared to be a small collapse of the crater walls exposing hot material deposited from yesterday's fountaining, as opposed to fresh lava in the crater.

The recent fountaining episodes at the summit of Kīlauea have covered the closed portion of Crater Rim Drive in Hawai‘i Volcanoes National Park with a significant amount of tephra. Tephra is the term for volcanic fragments that the travel through the air before being deposited on the ground.

Another view of the tephra covering Crater Rim Drive, at the summit of Kīlauea volcano. The tephra has also partially filled in some of the Southwest Rift Zone cracks that run perpendicular to the roadway. USGS photo by A. Flinders.

On March 21, USGS Hawaiian Volcano Observatory geologists sampled a small lobe of active lava in the eastern portion of Halema‘uma‘u crater, which represented residual lava oozing out from beneath the solidified crater floor. These ooze-outs have been common following fountaining episodes.

This photo shows the fountaining at Kīlauea summit at about 7:45 a.m. on March 20, during episode 14 of the ongoing eruption. At this time the south fountain was reaching the height of the crater rim, which is about 160 meters (520 feet) above the vent. USGS photo by M. Patrick. 

Just after 7:45 a.m. on March 20, the north fountain at the summit of Kīlauea abruptly shut off during episode 14, and the south fountain rose in height. The height was well above the crater rim, roughly 200 meters (650 feet) above the vent. USGS photo by M. Patrick.

Lava fountaining in the southwest portion of Halema‘uma‘u crater from episode 14 of the ongoing Kīlauea summit eruption. The south fountain was dominant around midday, and supplied lava into a long, narrow channel that fed into a circular perched lava pond. USGS photo taken by M. Patrick on March 20, 2025.

An HVO geologist captures video of the episode 14 fountaining at the summit of Kīlauea. The videos are time-synchronized to better compare to geophysical data, for later study. USGS photo taken by M. Patrick on March 20, 2025.

An HVO geologist uses a laser rangefinder to measure vent features during the episode 14 lava fountaining at the summit of Kīlauea. USGS photo by M. Patrick.

As episode 14 lava fountaining occurred during the ongoing Kīlauea summit eruption, the KWcam webcam, F1cam thermal camera and continuous laser rangefinder perched on the crater edge (upper right portion of the photo), provided a continuous record of activity.

Side-by-side comparison of Mauna Loa summit caldera maps from 1841 by Wilkes (top) and 1872 as published by the Pacific Commercial Advertiser newspaper (bottom). Note contour lines in the center of Mokuʻāweoweo caldera on the 1872 map, indicating a deeper depression that was discussed in a narrative of the mapping visit.