Kīlauea Summit Eruption - September 2021

Breaking news - on 29 September 2021 a new eruption commenced at the Kīlauea summit. A new lava lake is forming in Halema'uma'u crater. Volcanic gases are continuously released during eruptions of Kīlauea volcano, resulting in the potential for vog, downwind. Ashfall and other lightweight volcanic glass fragments from the lava fountains (e.g. Pele's hair) presently represents a minor hazard, but visitors to Hawai‘i Volcanoes National Park should be aware that, if trade winds are absent, ashfall and elevated concentrations of SO2, at publically accessible areas of the summit, are possible. Follow eruption updates at https://www.usgs.gov/volcano/volcano-updates or on social media https://www.usgs.gov/volcano/social-media.


Kilauea eruption 2021 courtesy of USGS

Kīlauea Volcano’s summit vent within Halema'uma'u crater is now erupting again. Fissures (cracks) have opened in the floor of the crater and in the crater wall. Lava is being erupted from these cracks. The opening phases of eruptions are dynamic and uncertain. The USGS Hawaiian Volcano Observatory continues to monitor the volcano closely and will report any significant changes. The photo on the right was taken by USGS staff at approximately 7:20 p.m. HST on 29 September 2021. 

From the USGS/HVO Volcanic Activity Notice:
Issued: Wednesday, September 29, 2021, 3:42 PM HST

This new eruption at Kīlauea’s summit is occurring within a closed area of Hawai'i Volcanoes National Park. Therefore, high levels of volcanic gas are the primary hazard of concern, as this hazard can have far-reaching effects down-wind. Large amounts of volcanic gas—primarily water vapor (H2O), carbon dioxide (CO2), and sulfur dioxide (SO2)—are continuously released during eruptions of Kīlauea Volcano. As SO2 is released from the summit, it will react in the atmosphere to create the visible haze known as vog (volcanic smog) that has been observed downwind of Kīlauea. Vog creates the potential for airborne health hazards to residents and visitors, damages agricultural crops and other plants, and affects livestock. For more information on gas hazards at the summit of Kīlauea, please see: https://pubs.er.usgs.gov/publication/fs20173017. Vog information can be found at https://vog.ivhhn.org/.
Additional hazards include Pele's hair and other lightweight volcanic glass fragments from the lava fountains that will fall downwind of the fissure vents and dust the ground within a few hundred meters (yards) of the vent (s). Strong winds may waft lighter particles to greater distances. Residents should minimize exposure to these volcanic particles, which can cause skin and eye irritation.
Other significant hazards also remain around Kīlauea caldera from Halemaʻumaʻu crater wall instability, ground cracking, and rockfalls that can be enhanced by earthquakes within the area closed to the public. This underscores the extremely hazardous nature of Kīlauea caldera rim surrounding Halemaʻumaʻu crater, an area that has been closed to the public since late 2007.


Useful resources:

The Interagency Vog Dashboard (front page) has links to current air quality information, vog forecasts and guidance on how to protect yourself from vog.

Updated: 30 September 2021