USGS Volcano Notice - DOI-USGS-HVO-2023-09-10T11:37:11-07:00

Activity Summary: Kīlauea volcano is not erupting. Kīlauea's summit is currently exhibiting signs of elevated unrest, specifically in an area south of its caldera. No unusual activity has been noted along the volcano's East Rift Zone or Southwest Rift Zone.

Summit Observations: Elevated seismic activity continues in an area south of Kīlauea’s summit caldera. Steady rates of earthquakes have persisted in this area since August 22, with about 150 earthquakes—all smaller than magnitude 2—occuring over the past day. Most of these earthquakes have occurred at depths of 2–3 kilometers (1–2 miles) below the surface, lacking upward migration. Recent tiltmeter measurements have indicated the southern area is inflating—independent of the usual deformation source inside the caldera—and Global Positioning System (GPS) measurements support this assessment. Within the caldera, tilt switched from slightly inflationary yesterday to slightly deflationary just before midnight. Sulfur dioxide (SO₂) emissions from the summit remain low; the most recent SO₂ emission rate of approximately 70 tonnes per day was measured on September 8.

The seismic and tilt data indicate that Kīlauea's summit region—and specifically the area south of the caldera—is becoming increasingly pressurized. Similar episodes of earthquake and ground deformation activity occurred in November 2020 and August 2021, prior to intra-caldera eruptions in December 2020 and September 2021. The unrest is currently confined within Kīlauea’s summit region and, if it continues, could escalate to an eruption in the coming days, weeks, or months. The activity could also decrease due to intrusion of magma underground or other changes, resulting in no eruption. Furthermore, levels of activity are expected to rise and fall during this period of unrest.

Halemaʻumaʻu Lava Lake Observations: No active lava has been observed since June 19. A live-stream video of the inactive western lava lake area is available at https://www.youtube.com/usgs/live.

Rift Zone Observations: No unusual activity has been noted along the East Rift Zone or Southwest Rift Zone; steady rates of ground deformation and seismicity continue along both. Measurements from continuous gas monitoring stations downwind of Puʻuʻōʻō in the middle East Rift Zone—the site of 1983–2018 eruptive activity—remain below detection limits for SO₂, indicating that SO₂ emissions from Puʻuʻōʻō are negligible.

Hazard Analysis: The latest eruptive activity at Kīlauea's summit occurred at the base of Halemaʻumaʻu crater, within the closed area of Hawaiʻi Volcanoes National Park. During Kīlauea summit eruptions, the high level of volcanic gases—primarily water vapor (H₂O), carbon dioxide (CO₂), and sulfur dioxide (SO₂)—being emitted is the primary hazard of concern, as this hazard can have far-reaching effects downwind. Passive volcanic degassing can occur from within Halemaʻumaʻu crater even during periods of no eruptive activity. As SO₂ is released from the summit, it reacts 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.

Other significant hazards also remain around Kīlauea's summit 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 the rim surrounding Halemaʻumaʻu crater, an area that has been closed to the public since early 2008.

For discussion of Kīlauea hazards, please see: https://www.usgs.gov/observatories/hawaiian-volcano-observatory/hazards.

Please see the Hawaiʻi Volcanoes National Park website for visitor information: https://www.nps.gov/havo/index.htm.

The Hawaiian Volcano Observatory (HVO) continues to closely monitor Kīlauea volcano.

Next Notice: HVO will issue daily Kīlauea updates. Additional messages will be issued as needed.