USGS Volcanoes: Notices released in the last day.

Strong northwesterly winds in the vicinity of Katmai and the Valley of Ten Thousand Smokes have picked up loose volcanic ash erupted during the 1912 Novarupta-Katmai eruption and are carrying it to the southeast. The National Weather Service has issued a SIGMET (https://www.weather.gov/aawu/sigmets) for this low-level event and suggests that the maximum cloud height is 6,000 ft (1.8 km) above sea level.

This phenomenon is not the result of recent volcanic activity and occurs during times of high winds and dry snow-free conditions in the Katmai area and other young volcanic areas of Alaska. No eruption is in progress. All of the volcanoes of the Katmai area (Griggs, Katmai, Novarupta, Mageik, Martin, Snowy and Trident) remain at Aviation Color Code GREEN and Alert Level NORMAL. Resuspended volcanic ash should be considered hazardous and could be damaging to aircraft and health.

For more information on volcanic ash and human health, visit the following website: http://volcanoes.usgs.gov/ash/

Official warnings about these ash resuspension events are issued by the National Weather Service: https://www.weather.gov/afc/

Forecasts of airborne ash hazard to aircraft: https://www.weather.gov/aawu/. Volcanic Ash Advisories: https://www.weather.gov/vaac/

Forecasts of ashfall: http://www.weather.gov/afc

Air quality hazards and guidance from Alaska Department of Environmental Conservation, Division of Air Quality: http://dec.alaska.gov/Applications/Air/airtoolsweb/Advisories/Index

Lava continues to erupt in the summit crater of Great Sitkin Volcano at a low rate with minor seismic activity. Slightly elevated surface temperatures were evident in a few satellite views over the past day. Clouds obscured web camera views. 

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.

Shishaldin Volcano continues to experience unrest. Webcam images captured yesterday revealed a minor steam plume rising from the summit. Over the past 24 hours, occasional small earthquakes and infrasound signals have been detected. These signals could be caused by gas bubbles bursting deep within the crater. Satellite views, under clear conditions, showed possibly elevated surface temperatures at the summit crater. Hot gases are likely responsible for the thermal signals 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 December 01 (0000h PST) to December 07 (2359h PST):

Typical seismicity was recorded at The Geysers geothermal field south of the Clear Lake Volcanic Field; 116 earthquakes greater than M1 were recorded, with the largest having a magnitude of M2.4.

One earthquake greater than M1 was recorded in the Long Valley Caldera, with a magnitude of M2.2.

Six 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.

Two earthquakes greater than M1 were recorded in the Coso Volcanic Field, with the largest having a magnitude of M1.4.

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

Activity Summary:

Kīlauea is not erupting, but moderate glow continued overnight in the flow field and from cracks near the north vent. It is too early to make an accurate forecast, but the onset of the next episode of fountaining is likely 2-3 weeks away.

Summit Observations:

Steady glow continued overnight from the crack adjacent to the north vent and intermittent glow from the south vent.  Incandescent spots remain visible on the creeping spatter fed flows to the south of the south vent.  

Since the end of episode 38, Kilauea has inflated 8.5 microradians as recorded on the UWD tiltmeter this morning with an increase of 2.0 microradians over yesterday.

Volcanic gas emissions have greatly decreased with the end of the eruption and are back in the normal range of 1200 to 1500 tonnes per day of SO₂.

Rift Zone Observations:

Rates of seismicity and ground deformation remain very low in the East Rift Zone and Southwest Rift Zone. SO₂ emissions from the East Rift Zone remain below the detection limit. 

Analysis:

The rapid rebound of inflationary tilt, continued tremor, and moderate glow from both vents overnight all indicate another fountaining episode is likely. It is still too early to make an accurate forecast. Based on current conditions and past events, the onset of another fountain episode is likely 2-3 weeks away at this time.

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

Recap of previous episode:

Episode 38 fountaining from the south vent stopped at approximately 8:52 p.m. HST on December 6 after 12.1 hours of sustained fountaining. The two vents within the north vent both stopped much earlier at 11:50 a.m. HST.  Sustained fountaining began at 8:45 a.m. HST from the two vents in the north cone after about 5 hours of precursory overflows.  The south vent fountain began at 8:49 a.m. HST and within 10-20 minutes all three fountains were about 500 (150 m) high creating a rare triple fountain.  By 9:40 a.m. the south vent fountain grew to about twice as high as the north vent fountains. The highest peak or instantaneous effusion rate of 1,300 cubic yards per second (1,000 cubic meters per second) occurred just before 10 a.m. when the south vent exploded. The enlarged south vent produced an inclined fountain over 1,000 feet (300 meters) tall that sprayed the south wall of Halemaʻumaʻu crater. Hot pumice and molten spatter from this fountain destroyed the HVO "V3" streaming camera site. The south fountain gradually dropped in height throughout the afternoon to about 500 feet (150 meters) high along with declining effusion rates. Episode 38 ended with an average effusion rate of 250 cubic yards per second (190 cubic meters per second). An estimated 16.5 million cubic yards (12.6 million cubic meters) of lava erupted and covered about 50-60% of the floor of Halemaʻumaʻu crater. The Uēkahuna tiltmeter (UWD) recorded about 33.1 microradians of deflationary tilt during episode 38.

The following notices from December 6 provide more information about episode 38:

• Volcano Activity Notice for End of Eruption (9:08 PM HST)
• Status Report on Fountain Height and Loss of V3 camera (10:41 AM HST)
• Volcano Activity Notice for Start of Eruption (8:48 AM HST)
• Kīlauea Update for December 6 (8:25 AM HST)

The following links provide more information about the current eruption that began on December 23, 2024:

• 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
• Two 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

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.