USGS Volcanoes: Notices released in the last day.

Lava continues to erupt in the summit crater of Great Sitkin Volcano. Seismicity at the volcano is at a low level, with occasional small earthquakes occurring over the past day. Satellite observations show continued inflation of the southeastern half of the lava dome. No other significant activity was observed in partly cloudy satellite and webcam 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.

Unrest continues at Shishaldin with frequent small earthquakes detected over the past day. Minor steam emissions continue to be observed in web camera views. No significant activity was observed in partly cloudy satellite views.

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. 

Activity Summary:

Over last night, the south vent showed persistent glow, while the north vent glowed intermittently. Nonetheless both vents are fuming this morning. Minor glow could be seen on the slopes around the vents, with bursts associated with rockfalls on the slope uncovering hot material. Preliminary results for the forecast window suggest that episode 37 could occur between November 22 to November 9. 

Summit Observations:

Glow was observed from both vents overnight. The glow varied from weak to strong, with the south vent glow generally stronger.  Only a few spots of incandesence were visible around the vents and the small avalanches of incandescent material appear to have stopped.

The UWD tiltmeter has since recorded about 9.3 microradians of inflationary tilt since the end of episode 37. Tremor spikes continue every 5-10 minutes apart and appear to be related to gas pistoning deeper in the vents.

Plumes of gas from both the south and north vents are visible this morning and sulfur dioxide (SO₂) gas emissions remain at background levels, typically between 1,200 and 1,500 tonnes per day. Moderate trade winds are present at the summit of Kīlauea this morning and are blowing from the northeast to the southwest.

Episode 36 began at approximately 11:15 a.m. HST on November 9 and ended at 4:16 p.m. HST on November 9. The north vent stopped earlier, at 3:38 p.m. HST, and the south vent gradually decreased in height and volume until it stopped erupting at 4:16 p.m.. South vent fountains reached heights of about 1,200 feet (360 meters) and north vent fountains reached heights of about 750 feet (230 meters). Episode 36 fountains produced just under 11 million cubic yards ( about 8 million cubic meters) of lava. The combined average eruption rate was over 600 cubic yards per second (500 cubic meters per second) from the dual fountains. Lava flows from the fountains covered about 80 percent of the floor of Halemaʻumaʻu crater.

The following notices provide more information about episode 36:

• VAN VONA End of Episode 36
• VAN VONA Start of Episode 36
• Kilauea Daily Update November 9

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
• 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. SO₂ emissions from the East Rift Zone remain below the detection limit.

Analysis:

Continued inflation, glow from the vents, and tremor all indicate that another fountaining episode is likely. Preliminary results for the episode 37 forecast window suggest that it could occur between November 22 and November 29. This forecast is likely to change in the coming days as more data becomes available.. 

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.

Signs of unrest at Ahyi Seamount have been observed routinely in satellite data over the past few weeks with plumes of discolored water observed drifting up to 1 mile (1.6 km) away from the volcano in satellite images on October 20, 21, 26, 28 and November 5. No high resolution satellite data were available over the past week. There was one signal observed on underwater pressure sensors near Wake Island (1,410 miles east of Ahyi) that may be related to activity at Ahyi. No other signals were detected from the direction of Ahyi Seamount from these hydroacoustic array data, although submarine plumes have been observed at the volcano in the past without clear hydroacoustic signals.

There are no local monitoring stations near Ahyi seamount, which limits our ability to detect and characterize volcanic unrest there. We will continue to monitor satellite and distal hydroacoustic data for additional evidence for, or escalation of, volcanic activity.

NORTHERN MARIANAS VOLCANOES
No signs of unrest were detected at any Northern Mariana Island volcanoes during the past week, other a possible hydroaccoustic signal from Ahyi Seamount. 

Monitoring of Northern Mariana Islands Volcanoes

Northern Mariana Island volcanoes are monitored using seismo-acoustic sensors on Saipan, and by examining satellite imagery. We also use distant seismic stations in Guam and Chichijima, Japan, and hydroacoustic data from Wake Island, when available. 

This level of monitoring can detect significant volcanic activity in the CNMI but cannot provide advanced warning of eruptions.

Due to a lack of geophysical monitoring on any of the volcanic islands, all volcanoes have alert levels of UNASSIGNED. This includes Ahyi, Anatahan, Sarigan, Farallon de Pajaros, Supply Reef, Maug, Asuncion, Agrigan, Pagan, Almagan, and Guguan.