USGS Volcano Notice - DOI-USGS-HVO-2024-09-17T19:43:45+00:00

Activity Summary: Kīlauea volcano is erupting in Hawai’i Volcanoes National Park from a new fissure vent that opened within Nāpau Crater this morning between 4:00 and 5:00 AM HST. Current eruptive activity began with a small eruption that occurred on the evening September 15 from a fissure located just west of Nāpau Crater and lasted a few hours. A second phase of the eruption began at approximately 6:00 PM last night. Activity decreased overnight until approximately 4:00 AM this morning, when a third phase of the eruption began. The eruption is occurring within a closed and remote area of Hawaiʻi Volcanoes National Park. There is no immediate threat to life or infrastructure. Chain of Craters Road, which is closed, is located far downslope and downwind of the eruption. 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: Approximately 17 earthquakes were detected beneath the Kīlauea summit region over the past 24 hours, at depths of 1–3 km (0.6–1.9 mi) below the ground surface, and with magnitudes of M2 or less. Summit tiltmeters (UWE, SDH, and IKI, to the northwest, southwest, and east of the summit respectively) continued recording deflationary tilt throughout the day yesterday, with UWE recording approximately 10 microradians of tilt in the last 24 hours. This pattern is consistent with magma leaving the summit storage chambers and transferring to the middle East Rift Zone. The most recent measurement of SO₂ emission rate at the summit was 75 tonnes per day on August 20, 2024.  

Rift Zone Observations: This morning, several lava fountains approximately ten meters (yards) high are generating lava flows on the floor of Nāpau Crater. This fissure system opened between 4:00 and 5:00 AM HST this morning as detected by NOAA GOES satellite thermal data and USGS Hawaiian Volcano Obseratory (HVO) infrasound, seismic, and camera instruments. Currently, the fissure system in Nāpau is about 0.5 km long (.3 mi) and cuts east-west across the northern crater floor. The fissure appears to have opened just west of Nāpau early this morning and propagated eastward as the eruption progressed.  As of 8:30 AM, approximately 25-30% of Nāpau Crater floor has been covered by lava, which is confined to the crater. Photos taken during an HVO overflight this morning are available here: September 17, 2024 —Kīlauea middle East Rift Zone eruption | U.S. Geological Survey (usgs.gov).

This eruption sequence was preceded by intense and localized earthquakes between Maunaulu and Makaopuhi Crater and accompanied by ground deformation patterns indicative of shallow underground crack growth or dike intrusion (a magma filled near vertical crack) began at approximately 6 PM HST on September 14, 2024 (Kīlauea Status Report — Middle East Rift Zone Unrest | U.S. Geological Survey (usgs.gov)).  In the following hours, the intensity of earthquake activity decreased, but over 340 shallow earthquakes were detected in the vicinity of the intrusion during the next 24 hours, most within 1 km – 5 km (0.6 mi – 3.1 mi) of the surface. Seismic and deformation data showed that magma was moving beneath the ground from summit storage chambers to the area between Maunaulu and Makaopuhi Crater. An InSAR image showing recent ground extension related to the dike intrusion in this area is available here: https://www.usgs.gov/media/images/september-15-2024-insar-image-kilauea-intrusion.  

The initial phase of the eruption started on September 15 around 9:00 PM HST and continued until approximately 10:00 PM.  Heavy rainfall hampered visibility of the region, but USGS HVO infrasound instruments and seismometers detected a signal typical of gas or steam venting in the middle East Rift Zone and USGS HVO issued a VAN/VONA raising the alert level to Watch/Orange.  A helicopter overflight on the morning of September 16 identified several new but inactive fissure segments 480 meters (yards) in total length with small pads of lava extending up to 90 meters (yards) from the fissures.   Measurement of sulfur dioxide emission rates along Chain of Craters road downwind of the eruption site during the day of September 16 indicated that the inactive fissure system was emitting around 300 metric tonnes a day.

The second phase of the eruption began on September 16 between 6:00 and 7:00 PM HST. This eruptive pulse began with no associated geophysical signals. No changes in seismicity, infrasound, or tilt were observed.  It was detected by NOAA GOES satellite thermal imagery and HVO webcam imagery. Eruptive activity gradually decreased throughout the night and ended by the early morning hours of September 17 prior to the onset of the more vigorous third phase that began between 4:00 and 5:00 AM.

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

A reference map of the middle East Rift Zone, with past lava flow extents, is available here: https://www.usgs.gov/maps/kilauea-middle-east-rift-zone-reference-map.

For more information about the meaning of volcano alert levels and aviation color codes, see https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes.

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. Temporary closures have been implemented as a result of this elevated activity; please see the Hawaiʻi Volcanoes National Park website for visitor information: https://www.nps.gov/havo/index.htm.  

Analysis: The ongoing MERZ eruption in the region of Nāpau Crater is the first in that area since the multi-day 1997 Napau fissure eruption.  The eruption is currently in its third phase of vent opening and lava production.  Multi-day fissure eruptions are not unusual and at this time it is difficult to say how long the eruptive activity may continue.  Currently, summit deflation recorded by both the Uēkahuna (UWE) and Sandhill (SDH) tiltmeters indicate a constant transfer of magma from the summit to the eruption site.  As long as magma is being supplied to the MERZ, the eruptive activity is likely to continue.

Updates: The Hawaiian Volcano Observatory (HVO) is watching the situation closely and additional messages will be issued as needed. 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.