Hawaii Volcanoes National Park, United States - December 05, 2025 Tephra blasted out by lava fountains during the ongoing Kilauea summit eruption has built a new puu, or hill, southwest of Halemaumau crater, now visible from public viewing areas around the summit. Tephra, including Pele’s hair, has been falling on a closed stretch of Crater Rim Drive since the current eruption began, but the new puu started forming in late March and early April. HVO geologists first tracked the growing deposit by photographing a road sign as it was progressively buried, until only an inch or two remained by the end of episode 21 on May 11. Before and after episode 22, geologists set up five-foot garden stakes along the closed road to measure tephra fall after each episode. That plan failed as episode 23 on May 25 buried five of the twelve stakes, and episode 24 on June 4 buried three more. Low-tech methods gave way to high-precision GPS surveys. After episodes 23 and 24, and fully after episode 25, geologists walked transects along the now-buried Crater Rim Drive, recording positions for four minutes at each site once satellites provided vertical accuracy of 30 centimeters or better. Processed with data from a permanent GPS station and 2019 lidar elevations, the measurements track the puu’s growth to within about 10 centimeters. HVO has also flown helicopter-mounted airborne lidar over the new hill about once a month to scan its three-dimensional shape, though processing remains complex. Photogrammetry methods used elsewhere at the summit have not worked here because the puu’s surface is too uniform. Data show how quickly the hill can grow during fountaining. At the former road sign location, the tephra layer reached 3.4 meters on May 31, 2025, after episode 23. Episode 24 added 7.8 meters more in about 7½ hours, and episode 36 added another 7.5 meters in just 5 hours. The puu grows most when lava fountains exceed 300 meters in height. Kilauea has been erupting episodically within the summit caldera since December 23, 2024, with a USGS Volcano Alert Level of WATCH. Episode 37 fountaining lasted 9 hours on November 25, and another episode is considered likely between December 6 and 9. No unusual activity has been detected along the East Rift Zone or Southwest Rift Zone. Mauna Loa is not erupting and remains at a NORMAL alert level. One M3.5 earthquake west of Pahala at 32 kilometers depth was reported felt on November 29. HVO continues to closely monitor both volcanoes.