USGS Volcano Notice - DOI-USGS-HVO-2023-09-16T11:22:30-07:00

Activity Summary: The Kīlauea summit eruption that began on September 10th continues this morning. Eruptive activity is confined to the downdropped block and Halemaʻumaʻu crater within Kīlauea's summit caldera. No unusual activity has been noted along Kīlauea’s East Rift Zone or Southwest Rift Zone. 

Summit Eruption Observations: Vents continue to erupt on the western side of the downdropped block within Kīlauea's summit caldera and are generating lava flows onto Halema‘uma‘u crater floor. Effusion and gas emissions continue to decrease and the eruption continues at a greatly diminished rate.

• Field crews observed eruptive activity greatly decrease or cease at several vents yesterday morning. This morning, webcam imagery shows little or no fountaining since 7 a.m., however, intermittent spattering was seen from the westernmost large cone throughout the night. Thermal images show that lava continues to flow onto the crater floor consistent with a very low level eruption.
• Pāhoehoe lava flows continue to flow from the vent area in north and west directions around elevated ground from the 1982 eruption and onto the eastern part Halema‘uma‘u crater floor. Webcam imagery over the past day shows that the area of active lava has retreated even further towards the vents though numerous oozeouts of lava were visible over other parts of Halema‘uma‘u crater floor overnight.  
• The laser rangefinder is aimed at a western portion of Halema‘uma‘u, not near the new eruptive activity, recorded little change over the past 24 hours. Since the eruption started, about 10 meters (33 feet) of uplift has been recorded at this locality demonstrating that lava intruded beneath the pre-existing crust within Halema‘uma‘u.
• Volcanic gas emissions in the eruption area are elevated; the most recent SO2 emission rate of 20,000 tonnes per day was measured the afternoon of September 13.  This is down significantly from the 190,000 tonnes per day measured just after the onset of the eruption on Sunday, September 10th.
• The live-stream video of the eruption is temporarily unavailable this morning. When active again, it will be available at https://www.youtube.com/usgs/live.
• More eruption information is available at: https://www.usgs.gov/volcanoes/kilauea/recent-eruption. 

Summit Observations: Summit tilt has was mildly inflationary most of the past 24 hours, with a switch to mild deflation early this morning. Summit seismic activity is dominated by eruptive tremor (a signal associated with fluid movement) with very few volcano tectonic earthquakes.

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: Eruptive activity is occurring on the downdropped block and Halemaʻumaʻu crater, within Kīlauea's summit caldera and in 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)— and fine volcanic particles are the primary hazards of concern, as these hazards can have far-reaching effects downwind.

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.

Strong winds may waft fine rock particles to areas downwind of erupting vents. People should minimize their exposure to these fine volcanic particles, which can cause skin and eye irritation.  Reports from Hawaiian Volcano Observatory field crews indicate that fine particles of Pele's Hair and other tephra are being deposited in the area near the Keanakāko‘i Overlook, which is approximately half a mile (about 1 km) from the eruption site. Hawaiʻi Volcanoes National Park has closed the Keanakāko‘i Overlook to the public at this time.

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.