USGS Volcano Notice - DOI-USGS-HVO-2024-09-19T18:01:42+00:00

Activity Summary: Kīlauea volcano continues to erupt in Hawai’i Volcanoes National Park from the new fissure vent that opened just west of Nāpau Crater yesterday, September 18, afternoon around 3:15 PM HST. This is the fourth vent system of this eruption and it began rapidly creating lava cascades or lava falls that poured over the western cliffs of Nāpau Crater.  The activity continued over night and the lava falls were visible on the S2 webcam this morning.  The eruption is occurring within a closed and remote area of Hawaiʻi Volcanoes National Park. There is no immediate threat to life or infrastructure. Residents of nearby subdivisions may experience volcanic gas emissions related to this activity which may increase and decrease over the coming hours and days. The Volcano Alert Level/Aviation Color Code remains at WATCH/ORANGE. No changes have been detected in the lower East Rift Zone or Southwest Rift Zone.

Summit Observations: Only 1 small, shallow earthquake was detected beneath the Kīlauea summit region over the past 24 hours. The summit tiltmeter at Sandhill continues to record strong deflation, while weaker deflation is being recorded by the tiltmeter at Uēkahuna. This pattern indicates that the summit magma body continues to supply magma to the middle East Rift Zone. The most recent measurement of SO₂ emission rate at the summit was 60 tonnes per day on September 17, 2024.  

Rift Zone Observations: The eruptive fissure west of Nāpau Crater remained active overnight and continues to feed lava cascades into the crater that have covered approximately 250,000 square meters (300,000 square yards) or a third of the crater floor since the new eruption began yesterday afternoon. The rate of coverage indicates lava is erupting at roughly 5-15 cubic meters per second (6-16 cubic yards). At the time of this notice, fountaining remained strong as observed on the S2cam (see link below).  In total, approximately two thirds of Nāpau Crater floor (500,000 square meters or about 125 acres) has been covered during this eruption since Sunday night.

Shallow earthquakes remain very low in the MERZ with about 20 in the past 24 hours. Most of these were to the west and northwest of Nāpau Crater. Tremor remains strong on the MERZ seismometers close to the eruption site and increased significantly with the onset of the new vent yesterday.

Tiltmeters in the MERZ continue to show no significant changes.  Recent position solutions from GPS instruments have shown displacements of over 20 cm (8 inches) for several stations in the MERZ.  The largest displacement is for station MKAI, just downslope of Makaopuhi Crater, which has experienced 54 cm (1.8 feet) of south-southwest motion since September 14.  The combination of large GPS displacements and modest tilt rates suggests that much of the deformation is the result of magma entering a storage region several kilometers (1-2 miles) below the surface. 

Sulfur Dioxide (SO₂) emission rates measured yesterday, September 18, were 10,000 tonnes per day for the new vent that opened in the afternoon.

All activity is currently confined to the middle East Rift Zone between Makaopuhi Crater and Puʻuʻōʻō and there are no indications of any changes further downrift in the MERZ or in the LERZ.

Additional Resources

• New S2cam, viewing the eruption from the east: https://www.usgs.gov/observatories/hvo/s2cam-view-napau-crater-east-rift-zone-kilauea-view-southwest
• Webpage with eruption-related resources: Eruption on Kīlauea middle East Rift Zone | U.S. Geological Survey (usgs.gov)
• Rapidly updated eruption monitoring map showing lava flow coverage and vent locations is available on the HVO home page: www.usgs.gov/hvo 
• Mapping data and a fully zoomable version of eruption monitoring map are available here: USGS Hawaii eruption map - preliminary (arcgis.com)
• September 17 eruption reference map: https://www.usgs.gov/maps/september-17-2024-kilauea-middle-east-rift-zone-eruption-reference-map

Analysis: The ongoing MERZ eruption is currently in its fourth phase of vent opening and lava production.  Each eruption has increased in volume with the current eruption being the largest to date.  Multi-day fissure eruptions are not unusual and current eruptive activity appears to be linked to supply of magma from the summit. 

Updates: HVO is continuing to closely monitor the middle East Rift Zone and is in contact with Hawai‘i Volcanoes National Park and the Hawai‘i County Civil Defense Agency. Please see the Hawaiʻi Volcanoes National Park website for visitor information: https://www.nps.gov/havo/index.htm. HVO will continue to provide daily updates for Kīlauea volcano. Should volcanic activity change significantly, a Volcanic Activity Notice will be issued. 

Hazards: High level of volcanic gas—primarily water vapor (H₂O), and sulfur dioxide (SO₂)—are emitted during eruptions and can have far-reaching effects downwind. As SO₂ is released from lava, it reacts in the atmosphere to create the visible haze known as vog (volcanic smog) that has been observed downwind of eruptive vents. 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.   

Shallow magma movement and eruptions can produce minor to severe ground fractures and subsidence features, which can affect the landscape, human activity, and infrastructure. These ground cracks can continue to widen and offset as magma migration continues, may have unstable overhanging edges, and should be avoided. 

Additional ground cracking and outbreaks of lava around the active fissures are possible at any time, or existing fissures can be reactivated. Hawaiian lava flows generally advance slowly downslope and can be avoided by people. They can destroy everything in their paths including vegetation and infrastructure—which can cut off road access and utilities. Hazards associated with active or recent lava flows include hot and glassy (sharp) surfaces that can cause serious burns, abrasions, and lacerations upon contact with unprotected or exposed skin; uneven and rough terrain can lead to falls and other injuries; hot temperatures that can cause heat exhaustion or dehydration, or in heavy rain can produce steamy ground-fog that can be acidic, severely limiting visibility and sometimes causing difficulty breathing.  

If new lava flows cover and burn vegetation and soil, they can ignite natural gas pockets in the subsurface, which can cause methane explosions. These explosions can blast lava fragments up to several meters (yards) away and can be hazardous to observers.

Pele's hair and other lightweight volcanic glass fragments from lava fountains and spattering will fall downwind, dusting the ground within a few hundred meters (yards) of the vent. High winds may waft lighter particles and transport them greater distances downwind. Exposure to these volcanic particles can cause skin and eye irritation.

Hazards 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 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.