USGS Volcanoes: Notices released in the last day.

Lava continues to erupt slowly at Great Sitkin Volcano. Ongoing activity is adding to a thick lava flow that fills most of the summit crater. Small earthquakes associated with the ongoing lava eruption continue. Satellite and web camera images were obscured by clouds over the past day. 

A single explosive event occurred in May 2021 and was followed by the ongoing eruption of lava that began in July 2021. No explosive events have occurred since May 2021. Local seismic and infrasound sensors and web cameras are used to monitor Great Sitkin along with regional infrasound and lightning networks and satellite data.

Activity Summary: Kīlauea is not erupting. Weak steaming continues on the inactive September 15-20 flow field within Nāpau Crater on the middle East Rift Zone. No changes have been detected in the lower East Rift Zone or Southwest Rift Zone.  

Summit Observations:  There were 11 earthquakes detected beneath the Kīlauea summit region over the past 24 hours. The summit tiltmeters at Uēkahuna and Sandhill show indications of slight inflation over the past few days. The most recent measurement of SO₂ emission rate at the summit was 60 tonnes per day on September 17, 2024.    

Rift Zone Observations:  The middle East Rift Zone (MERZ) eruption near Nāpau Crater stopped around 10 AM HST on the morning of September 20. Only minor steaming can be seen in webcam imagery from the eruption site at night since that time. No SO₂ from the eruption site was detected on Monday, September 23rd, during measurements on Chain of Craters Road, indicating that MERZ SO₂ emissions are approaching or at 0 tonnes per day. 

Shallow earthquake counts remain low in the MERZ and upper East Rift Zone and tremor is no longer being recorded on seismometers close to the eruption site.  Tiltmeters in the MERZ show no significant changes and GPS instruments show low but continuing rates of inflationary deformation.  

All recent activity was 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.  

Analysis:  Kīlauea erupted briefly in and near Nāpau Crater from September 15–20, 2024. Lava flows from this eruption covered more than 630,000 square meters (156 acres) of Nāpau Crater and areas to the west. A webpage with eruption-related resources is available here: Eruption on Kīlauea middle East Rift Zone | U.S. Geological Survey (usgs.gov) and a summary of the eruption is available in this “Volcano Watch” article: Volcano Watch — A New Kīlauea Eruption | U.S. Geological Survey (usgs.gov). 

While the East Rift Zone eruption has ended, unrest continues at a low level in this region of Kīlauea. Rates of seismicity and ground deformation have greatly decreased since the eruption, but data shows that magma is continuing to move at a low rate from the summit to the middle East Rift Zone. Future intrusive episodes and eruptions could occur with continued magma supply.

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

Hazards:  Near the recent middle East Rift Zone eruption site, minor to severe ground fractures and subsidence features may continue to widen and offset, may have unstable overhanging edges, and should be avoided. Hazards associated with the recent lava flows include glassy (sharp) surfaces that can cause serious abrasions, and lacerations upon contact with unprotected or exposed skin; uneven and rough terrain that can lead to falls and other injuries; or, locally elevated levels of volcanic gases that can lead to breathing difficulty.   

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.