USGS Volcanoes: Notices released in the last day.

Lava continues to erupt in the summit crater of Great Sitkin Volcano. Cloudy weather blocked views of the volcano from webcams and satellites. 

A power outage at AVO's data-receive facility in Adak has been resolved and monitoring data is being received by AVO. 

The current lava eruption began in July 2021 and since then has filled most of the summit crater and advanced into valleys below. There have been no explosions at Great Sitkin Volcano since an event in May 2021. The volcano is monitored using local seismic and infrasound sensors, satellite data and web cameras, and regional infrasound and lightning networks.

Frequent small earthquakes and infrasound signals, possibly caused by gas bubbles bursting deep within the volcanic conduit, continue at a rate similar to what has been seen during the current period of unrest. Today, webcam and satellite views of the volcano are cloudy and nothing was observed.

Local seismic and infrasound sensors, web cameras, and a geodetic network are used to monitor Shishaldin Volcano. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions. 

Monitored CALIFORNIA VOLCANOES
Current Volcano Alert Level: all NORMAL
Current Aviation Color Code: all GREEN

Activity Update: All volcanoes monitored by CalVO show normal background earthquake activity and deformation. Monitored volcanoes include Mount Shasta, Medicine Lake Volcano, Lassen Volcanic Center, Clear Lake Volcanic Field, Long Valley Volcanic Region, Coso Volcanic Field, Ubehebe Craters, and Salton Buttes.

Past Week Observations for October 06 (0000h PDT) to October 12 (2359h PDT):

Typical seismicity was recorded at The Geysers geothermal field south of the Clear Lake Volcanic Field; 91 earthquakes greater than M1 were recorded, with the largest having a magnitude of M2.0.

Eleven earthquakes greater than M1 were recorded in the Sierra Nevada Block, south of Mammoth Mountain and Long Valley, with the largest having a magnitude of M2.7.

Three earthquakes greater than M1 were recorded in the Coso Volcanic Field, with the largest having a magnitude of M2.8.

Three earthquakes greater than M1 were recorded near the Salton Buttes, with the largest having a magnitude of M1.6.

During the lapse in appropriations, the USGS Hawaiian Volcano Observatory (HVO) continues to maintain monitoring networks and issue updates and notifications of volcanic activity via the Hazard Notification Service. Volcano monitoring data will continue to be available on the HVO website. Static website content will not be updated until further notice and information may become outdated over time. For more information on the shutdown, please visit the Department of the Interior website at www.doi.gov.

Activity Summary:

Episode 34 lava fountaining ended October 1 at 7:03 a.m. HST after approximately 6 hours of continuous activity. Variable incandescence was visible in both the north and south vents last night, indicating that magma within the conduits is close to the surface. Seismic tremor indicates that gas piston events continue within the vents, but are more irregular compared to the past several days. Kīlauea's summit region continued to inflate over the past 24 hours, with rates indicating that the next fountaining episode is likely to start between October 17 and 21.

Summit Observations:

Halemaʻumaʻu continues to be quiet this morning with passive outgassing plumes rising from the north and south vents. Variable moderate to bright incandescence visible in the north vent last night was significantly more prominent than the less frequent incandescence visible in the south vent. The variable nature of the glow roughly correlates with irregular seismic tremor, but the patterns are less pronounced. This indicates that gas piston activity continues within both vents but at less regular intervals compared to the the early part of the repose period. The UWD tiltmeter shows continued inflationary tilt and as of this morning, the tiltmeter has recovered a total of approximately 19.7 microradians since episode 34 ended.

Episode 34 occurred over about 6 hours on October 1 and included lava fountaining from both the north and south vents. Lava fountains reached an estimated 1300 feet (400 meters), and both the north and south vents generated lava flows that covered a large portion of the western part of Halemaʻumaʻu. Episode 34 was preceded by several days of precursory activity, with over 120 gas piston events that produced small, sporadic spatter fountains 10 feet (3 meters) high and numerous short overflows of lava from the north vent. Deflationary tilt at UWD totaled approximately 26 microradians during episode 34 fountaining, with an estimated volume of approximately 12 million cubic yards (9 million cubic meters or 2.5 billion gallons) of lava erupted overnight. The dual fountains also produced a record combined effusion of 500 cubic yards per second, about twice the maximum eruptive rate measured in previous episodes.

Elevated degassing continues from the vents largely in bursts related to gas piston events. Overall, average sulfur dioxide (SO₂) emission rates during pauses are typically 1,200 to 1,500 t/d, though emission rates can vary on short time scales.

Strands of volcanic glass known as Pele’s hair are present throughout the summit area of Hawaiʻi Volcanoes National Park and surrounding communities and can be remobilized by wind even after lava fountaining has ceased.

• Eruption resources, including the most recent map and a timeline of eruption episodes since December 23, 2024: https://www.usgs.gov/volcanoes/kilauea/science/eruption-information
• Three Kīlauea summit livestream videos that show eruptive lava fountains are available here: https://www.youtube.com/@usgs/streams
• Summit eruption webcams: https://www.usgs.gov/volcanoes/kilauea/summit-webcams
• Volcano Watch article on gas pistons: https://www.usgs.gov/observatories/hvo/news/volcano-watch-so-what-earth-or-least-kilauea-a-gas-piston

Rift Zone Observations:

Rates of seismicity and ground deformation remain very low in the East Rift Zone and Southwest Rift Zone, with no significant earthquake activity in the past 24 hours outside of the summit. Sulfur dioxide (SO₂) emissions from the East Rift Zone remain below the detection limit.

Analysis:

The steady continuation of inflationary tilt following the end of episode 34 coupled with periods of strong glow indicates that the summit magma reservoir is repressurizing and is likely to lead to another lava fountaining episode. Variable weak to bright glow from both the vents last night, and irregular tremor spikes indicative of gas pistons indicate that magma is at high levels within both vents. The changes in behavior, uncoordinated periods of glow, and irregular tremor patterns indicate that gas piston events are not strongly coupled between the vents. The open nature of the south vent suggests it is still likely to play a prominent role in the next episode after staging a dramatic comeback in episode 34. Models of inflation continue to indicate that the start of episode 35 is likely to occur between October 17 and 21.

The current eruption has been characterized by episodic lava fountaining not seen in any eruptions since the 1983–86 episodic fountains at the beginning of the Puʻuʻōʻō eruption. Lava fountains and flows have erupted from two vents within Halemaʻumaʻu crater that we refer to as the north vent and south vent. Each of the previous fountaining episodes lasted from a few hours to over a week and was accompanied by strong deflation of the summit region. Pauses between the lava fountaining episodes have been marked by an immediate switch from deflation to inflation as the magma chamber recharges and repressurizes. Lava fountaining episodes have occurred approximately once per week since the start of the current eruption on December 23, 2024.

HVO continues to closely monitor Kīlauea and is in contact with Hawai‘i Volcanoes National Park and the Hawai‘i County Civil Defense Agency about eruptive hazards.

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

Hazards:

This episodic eruption is occurring within a closed area of Hawai'i Volcanoes National Park. High levels of volcanic gas—primarily water vapor (H₂O), carbon dioxide (CO₂), and sulfur dioxide (SO₂)—are one major hazard of concern, as this hazard can have far-reaching effects downwind. As SO₂ is continuously released from the summit during an eruption, it will react in the atmosphere to create the visible haze known as vog (volcanic smog) downwind of Kīlauea. SO₂ and vog may cause respiratory and other problems at high concentrations. Further information on vog can be found at https://vog.ivhhn.org/

Another major hazard is fallout of Pele's hair and other volcanic fragments from lava fountains. Pele's hair is strands of volcanic glass often produced by lava fountaining activity that can be carried well over 10 miles (15 kilometers) from the vent. Other hot glassy volcanic fragments (tephra) including volcanic ash, pumice, scoria, and reticulite can fall on the ground within 1–3 miles (1–5 kilometers) of the eruptive vent(s), with the highest concentrations immediately downwind of the vent(s). Various volcanic fragments have fallen on Highway 11 west of Hawai'i Volcanoes National Park at times, depending on wind and eruption conditions. Strong winds may waft light particles, including Pele's hair, to greater distances downwind. Once on the ground, Pele's hair can sometimes cluster and tangle together, giving it the appearance of a tumbleweed. The extent of Pele's hair deposition is dependent on lava fountaining activity and wind conditions. Residents and visitors should minimize exposure to Pele's hair and other glassy volcanic fragments, which can cause skin and eye irritation and can also contaminate catchment water supplies. More information about how Pele's hair, its hazards, and what to do is available here: https://www.usgs.gov/observatories/hvo/news/volcano-watch-recent-lava-fountains-highlight-peles-hair-hazards. A recently updated Frequently Asked Questions document that includes information about potential health effects of Pele's hair is available here: https://vog.ivhhn.org/sites/default/files/PelesHair_FAQs_v2.pdf

Hawaiian lava flows generally advance slowly downslope, and during this eruption flows have been confined to Halemaʻumaʻu crater and the southwest side of Kaluapele, Kīlauea's summit caldera.

Other significant hazards also 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 Kīlauea's caldera rim surrounding Halemaʻumaʻu crater, an area that has been closed to the public since late 2007.