Hawaiian Volcano Update: Kīlauea Summit Eruption’s Episode 22 & Pre-Episode 23 - May 22, 2025

Kīlauea’s summit eruption produced its 22nd episode of sustained fountaining starting last Friday, May 16, at 5:13 am, lasting over 10 hours from the north vent. During the first hour, fountains peaked over 1000 feet or 300 meters high, with lava flows covering 40% of Halemaʻumaʻu crater floor with about 5 million cubic yards of lava. Following the end of fountains, both vents exhibited glow throughout the week, and began to produce spatter and short-lived lava ponds by Wednesday, with episode 23 expected to begin its sustained fountains between today and Saturday. There continue to be no significant changes on either of Kīlauea’s rift zones.

Dominant trade winds over the past week limited the impact of increased volcanic gas and tephra output during episode 22, although variable winds in the days following somewhat exposed nearby communities to those effects. A similar weather pattern is expected in the next few days, with weakened trade winds potentially facilitating impacts on viewing areas within Hawaiʻi Volcanoes National Park as well as neighboring communities. Vog and tephra hazards have become common to island residents, and the usual precautions and preparations apply, especially for those with respiratory sensitivities – more information at https://vog.ivhhn.org/.

Maunaloa continues to inflate quietly its established post-eruption pattern, with only small-magnitude earthquakes and minor adjustments evident on monitoring instruments. As usual, we summarize the monitoring signals, imagery, and reports for both volcanoes available courtesy of the USGS Hawaiian Volcano Observatory, annotating the presentation on screen as we go and discussing live viewer questions.