ALASKA VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Friday, June 26, 2026, 12:13 PM AKDT (Friday, June 26, 2026, 20:13 UTC)
Slow eruption of lava continues within the summit crater. Growth of the lava dome to the east-southeast was observed in satellite radar imagery on June 22. Typical slightly elevated surface temperatures were observed throughout the week when cloud cover was not obscuring the volcano. Seismic activity remains low, with occasional small volcanic earthquakes and seismic signals from minor rockfalls observed. Web camera observations showed no evidence of activity.
The current lava eruption began in July 2021 and has filled most of the summit crater and advanced into the valleys below. There have been no explosions at Great Sitkin Volcano since an event in May 2021. The volcano is monitored using local seismic, geodetic, and infrasound sensors, satellite data, and web cameras, and regional infrasound and lightning networks.
Great Sitkin Volcano is a basaltic andesite volcano that occupies most of the northern half of Great Sitkin Island, a member of the Andreanof Islands group in the central Aleutian Islands. It is located 26 miles (42 km) east of the community of Adak. The volcano is a composite structure consisting of an older dissected volcano and a younger parasitic cone with a ~1 mile (1.6 km)-diameter summit crater. A steep-sided lava dome, emplaced in the crater during an eruption in 1974, has been mostly buried by the ongoing eruption. The 1974 eruption produced at least one ash cloud that likely exceeded an altitude of 25,000 ft (7.6 km) above sea level. A poorly documented eruption also occurred in 1945, producing a lava dome that was partially destroyed in the 1974 eruption. Within the past 280 years a large explosive eruption produced pyroclastic flows that partially filled the Glacier Creek valley on the southwest flank.
Earthquake activity continues near Mount Kupreanof volcano, with magnitudes mostly under 2.0 this week. Sulfur dioxide gas emissions were detected in satellite images on June 19, 22 and 23, and weakly elevated surface temperatures were detected on June 24 and 25.
AVO released an Information Statement on June 22 summarizing the ongoing volcanic unrest from a magmatic intrusion beneath the volcano, which is also now detected in satellite ground deformation data (satellite interferometric radar or InSAR). More details can be found in the Information Statement on the AVO website: https://avo.alaska.edu/news/view/kupreanof-information-statement-june-22-2026.
There is no real-time geophysical monitoring network at Mount Kupreanof. The closest functioning seismometer is approximately 17 miles (27 km) to the east of the volcano as part of the Mount Veniaminof network. Mount Kupreanof is also monitored by satellite data, regional infrasound and lightning networks, and visual observations from pilots and mariners passing by the volcano.
Mount Kupreanof is a heavily glaciated stratovolcano on the Alaska Peninsula with no known historical eruptions. Very little is known about its eruptive history. A single debris flow or block-and-ash flow deposit with a suspected Holocene age has been mapped in a valley south of the volcano. Eruptions will likely produce lahars and pyroclastic flows on the volcano's flanks and into the surrounding uninhabited valleys. Ash plumes could affect communities and airplanes downwind of the volcano. A vigorous fumarole field just west of the summit produces persistent steam plumes.
Seismic and infrasound activity remain elevated, with numerous small earthquakes, frequent infrasound signals from small explosions within the summit crater, and volcanic tremor recorded this week. Satellite data showed elevated sulfur dioxide emissions on most days and steam and gas emissions were observed in satellite and web camera images during periods of clear weather.
Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. In addition to the local monitoring network, the Alaska Volcano Observatory uses nearby geophysical networks, regional infrasound and lightning data, and satellite data to monitor the volcano.
Shishaldin Volcano, located near the center of Unimak Island in the eastern Aleutian Islands, is a conical stratovolcano with a base diameter of approximately 10 miles (16 km). It is one of the most active volcanoes in the Aleutian volcanic arc, with at least 54 episodes of unrest, including over 28 confirmed eruptions since 1824. Most eruptions are relatively small, although activity during the 1999 and 2023 eruptions generated ash columns that reached up to 46,000 ft (16 km) above sea level.
A small explosion was detected in seismic and infrasound data on June 24 at 5:59 AM AKDT (13:59 UTC) originating from the crater lake at Korovin Volcano, within the Atka Volcanic Complex. Brief explosive events at Korovin Volcano are not uncommon and can occur without precursory unrest. No emissions were detected associated with this activity and elevated seismicity declined immediately after the event.
To view monitoring data and other information about the Atka volcano complex: https://avo.alaska.edu/volcano/atka-volcanic-complex
The Atka volcanic complex forms the northern part of Atka Island, located about 16 km north of the community of Atka and 1,761 km southwest of Anchorage. The Atka volcanic complex includes a possible older caldera and several younger vents, including Korovin Volcano, Mount Kliuchef, and Sarichef Volcano. Korovin Volcano, a 1553-m-high (5030 ft) stratovolcano, has been the site of most historical volcanic activity, and has a small, roiling crater lake that occasionally produces energetic steam emissions. Korovin has erupted several times in the past 200 years, including 1973, 1987, and 1998, and has likely had small ash emissions as recently as 2005. Typical recent Korovin eruptions produce minor amounts of ash and occasional but small lava flows. Reports of the height of the ash plume produced by the 1998 eruption ranged as high as 10,600 m (35,000 feet) above sea level. Mount Kliuchef is composed of a series of five vents aligned northeast–southwest. The two main summit vents of Kliuchef appear relatively young and the easternmost was probably the source of an 1812 eruption that is sometimes attributed to Sarichef.
Matt Haney, Scientist-in-Charge, USGS, mhaney@usgs.gov (907) 786-7497
David Fee, Coordinating Scientist, UAFGI, dfee1@alaska.edu (907) 378-5460
Contact AVO: https://avo.alaska.edu/contact
The Alaska Volcano Observatory is a cooperative program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys.
CASCADES VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Friday, June 26, 2026, 12:10 PM PDT (Friday, June 26, 2026, 19:10 UTC)
Activity Update: All volcanoes in the Cascade Range of Oregon and Washington are at normal background activity levels. These include Mount Baker, Glacier Peak, Mount Rainier, Mount St. Helens, and Mount Adams in Washington State and Mount Hood, Mount Jefferson, Three Sisters, Newberry, and Crater Lake in Oregon.
Past Week Observations: During the past week, small earthquakes were detected at Mount Rainier and Mount St. Helens. All monitoring data are consistent with background activity levels in the Cascade Range. Field crews were out at Mount St. Helens conducting maintenance on monitoring stations.
The U.S. Geological Survey Cascades Volcano Observatory and the University of Washington Pacific Northwest Seismic Network continue to monitor Washington and Oregon volcanoes closely and will issue additional notifications as warranted.
Website Resources
For images, graphics, and general information on Cascade Range volcanoes: https://www.usgs.gov/observatories/cvo
For seismic information on Oregon and Washington volcanoes: http://www.pnsn.org/volcanoes
For information on USGS volcano alert levels and notifications: https://www.usgs.gov/programs/VHP/volcano-notifications-deliver-situational-information
Seth Moran, Acting Scientist-in-Charge, Cascades Volcano Observatory, smoran@usgs.gov
General inquiries: askCVO@usgs.gov
Media inquiries: volcanomedia@usgs.gov
Precursory low-level activity for episode 50 of the ongoing Halemaʻumaʻu eruption at the summit of Kīlauea increased around 8:50 a.m. HST on June 26 with a small lava overflow from the north vent along with increasing levels of spattering and gas jetting. Accordingly, HVO is raising the Alert Level for Kīlauea from ADVISORY to WATCH and the Aviation Color Code from YELLOW to ORANGE. Alert level and aviation color code definitions: https://www.usgs.gov/programs/VHP/alert-level-system. This low-level precursory activity can continue for hours to days before the lava fountaining episode beings. Lava fountain episode 50 is forecast to start today (most likely) or tomorrow. Another VAN will be published when lava fountaining episode 50 begins.
Surface winds below the inversion level (about 8,000 feet or 2,400 meters above sea level) are forecast to be moderate to strong tradewinds out of the northeast, which will move the lower part of the plume to the southwest. Above the inversion layer, light winds from the south are forecast up to 16,000 feet (5,000 meters) where they will turn to the southwest and strengthen. Higher level winds could push parts of the plume to the north over surrounding communities.
Most lava fountaining episodes since December 23, 2024, have continued for a day or less.
The National Weather Service has issued a Special Weather Statement regarding potential tephra impacts from episode 50: https://forecast.weather.gov/showsigwx.php?warnzone=HIZ053&warncounty=HIC001&firewxzone=HIZ339&local_place1=3%20Miles%20E%20Mountain%20View%20HI&product1=Special+Weather+Statement&lat=19.517&lon=-155.108
Hazard Analysis:
Volcanic Gas: water vapor (H2O), carbon dioxide (CO2), and sulfur dioxide (SO2) are continuously released during an eruption. SO2 reacts in the atmosphere to create the visible haze known as vog (volcanic air pollution) downwind, which may cause respiratory and other problems. Further information on vog can be found at https://vog.ivhhn.org/
Tephra: small glassy volcanic fragments—volcanic ash, pumice, scoria, Pele’s hair and reticulite—are created by the lava fountains. A combination of fountaining dynamics and wind conditions determines where tephra fall may occur for any given eruption episode. Larger particles fall near the vents while light particles may be wafted greater distances. These particles may be remobilized during windy conditions following recent eruptive episodes. Residents and visitors should minimize exposure to these fragments, which can cause skin, eye, and respiratory irritation. More information and guidance on tephra fall hazards is available at https://seagrant.soest.hawaii.edu/resource-and-guidance-for-volcanic-tephra-fall/
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 exist around Kīlauea caldera from Halemaʻumaʻu crater wall instability, ground cracking, and rockfalls that can be enhanced by earthquakes. Close to the vents, the tephra material on the crater rim is prone to cracking, slumping, and small landslides that sometimes expose hot and molten material within. 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.
HVO continues to closely monitor Kīlauea and will issue additional notices as needed based on activity. Regularly scheduled daily updates for Kīlauea are posted on the HVO website at https://www.usgs.gov/volcanoes/kilauea/volcano-updates
More Information:
Subscribe to these messages: https://volcanoes.usgs.gov/vns2/
Summary of volcanic hazards from eruptions: https://www.usgs.gov/observatories/hvo/hazards
Recent earthquakes in Hawaiʻi (map and list): https://www.usgs.gov/observatories/hvo
Explanation of Volcano Alert Levels and Aviation Color Codes: https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes
WMPA01 PHVO 261914
VONA
DTG: 20260626/1914Z
VOLCANO: KILAUEA 332010
PSN: N1925 W15517
AREA: HAWAII
SOURCE ELEV: 4091FT AMSL
NOTICE NR: 2026/40
CURRENT COLOUR CODE: ORANGE
PREVIOUS COLOUR CODE: YELLOW
SVO: HAWAIIAN VOLCANO OBSERVATORY
ACT STS: ERUPTION ONGOING
ONSET: UNKNOWN
DUR: ONGOING EPISODIC
VA CLD HGT: NO VA CLD PRODUCED
HGT SOURCE: NO VA CLD PRODUCED
MOV: NO VA CLD PRODUCED
CTC: HVO DUTY SCIENTIST: 808-785-3144
RMK: LOW-LEVEL ERUPTION OF LAVA BEGAN AT THE SUMMIT OF KILAUEA AT 8:50 AM ON JUNE 26,
2026. LOW-LEVEL ACTIVITY CAN PERSIST FOR HOURS TO DAYS BEFORE THE LAVA FOUNTAIN
EPISODE BEGINS. LAVA FOUNTAIN EPISODE 50 IS FORECAST TO START TODAY (MOST LIKELY) OR
TOMORROW.
NXT NOTICE: A NEW VONA WILL BE ISSUED IF COND CHANGE SIGNIFICANTLY OR IF THE COLOR CODE CHANGES
NNNN
HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Friday, June 26, 2026, 7:28 AM HST (Friday, June 26, 2026, 17:28 UTC)
Overview:
The summit eruption of Kīlauea in Halemaʻumaʻu has resumed with weak precursory spattering and gas jetting of spatter that made small spatter deposits outside of both vents. Summit inflation, strong vent glow, flaming, increasing spattering, and degassing continues, indicating that another episode is likely. No overflows have occurred as of this time. Seismic and inflation-based forecast models indicate that the onset of fountaining episode 50 is most likely to begin today June 26 with a lower possibility of Saturday June 27.
No significant activity has been noted along Kīlauea’s East Rift Zone or Southwest Rift Zone.
NOTE: Significant changes in activity between Daily Updates are posted here: https://www.usgs.gov/observatories/hvo/observatory-messages
Summit Observations:
Continuous strong glow and intermittent spattering was visible on webcams from both vents in Halemaʻumaʻu overnight. Around 3 a.m. HST, the frequency of visible north vent spattering increased significantly, and the intensity of cyclic gas jetting and spattering at the south vent increased as well. The south vent continued to produce large flames and intermittent sprays of fine spatter caused by gas jetting every 5-10 minutes that correlate with strong tremor spikes. North vent spatter bursts are smaller, but are now more continuously visible. No overflows have occurred at this time, but small amounts of spatter have been deposited outside of both vents. Magma is very close to the surface.
Spikes of seismic tremor preceded by periods of low tremor continued (every 5-10 minutes) for most of the past day. Cyclic tremor became much less regular around 5 a.m. HST this morning and more widely spaced in time. One small earthquake (less than M2) was located beneath Kīlauea volcano's summit in the past 24 hours.
Kīlauea summit deflation totaled 15.5 microradians during episode 49. Once the episode ended, inflation resumed and has since recovered 16 microradians of tilt at the summit tiltmeter at Uēkahuna (UWD).
With the eruption now paused, the sulfur dioxide (SO2) emission rate from the summit is likely now varying within a typical range of 1,000 to 5,000 tonnes per day. Surface winds below the inversion level (about 8000 feet or 2400 meters above sea level) are forecast to be moderate to strong tradewinds out of the northeast, which will move the lower part of the plume to the southwest. Above the inversion layer, light winds from the south are forecast up to 16000 feet (5000 meters) where they will turn to the southwest and strengthen. Higher level winds could push parts of the plume to the north over surrounding communities.
Rift Zone Observations:
Rates of seismicity and ground deformation remain low in the East Rift Zone and Southwest Rift Zone. SO2 emissions from the East Rift Zone remain below the detection limit.
Analysis:
The abrupt switch from deflation to inflation at the end of episode 49 along with continued tremor, glow and increased intensity of spattering from the vents indicates that episode 50 fountaining is likely. Magma remains close to the surface and spattering began last night. Current inflation since the end of episode 49 has now exceeded the tilt lost in that episode. Both inflation and seismic based forecast models suggest the onset of episode 50 is most likely today, Friday June 26, or possibly tomorrow, Saturday, June 27.
Kīlauea has been erupting episodically since December 23, 2024, from two vents (north and south) in Halema‘uma‘u. Lava fountaining episodes, which generally last for less than 12 hours, are separated by pauses that can be longer than three weeks.
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
Summary of episode 49:
A detailed account of episode 49 is given in the HVO Status Report Issued June 14: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-06-15T03:23:25+00:00
Resources:
NOTE: HVO’s monitoring network is mostly recovered from recent power- and storm-related outages. Several summit stations, including the SDH tiltmeter, will remain offline until we are able to re-establish access across the deep tephra field southwest of the caldera.
The following links provide more information about the current eruption that began on December 23, 2024:
Hazards:
This episodic eruption is occurring within a closed area of Hawai'i Volcanoes National Park.
Other significant hazards exist around Kīlauea caldera from Halemaʻumaʻu crater wall instability, ground cracking, and rockfalls that can be enhanced by earthquakes. Close to the eruptive vents, the tephra material on the crater rim is prone to cracking, slumping, and small landslides that sometimes expose hot and molten material within. 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.
More Information:
The Hawaiian Volcano Observatory is one of five volcano observatories within the U.S. Geological Survey and is responsible for monitoring volcanoes and earthquakes in Hawaiʻi and American Samoa.
Subscribe to these messages: https://volcanoes.usgs.gov/vns2/
Summary of volcanic hazards from eruptions: https://www.usgs.gov/observatories/hvo/hazards
Recent earthquakes in Hawaiʻi (map and list): https://www.usgs.gov/observatories/hvo
Explanation of Volcano Alert Levels and Aviation Color Codes: https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes
NORTHERN MARIANA ISLANDS WEEKLY UPDATE
U.S. Geological Survey
Friday, June 26, 2026, 7:05 AM ChST (Thursday, June 25, 2026, 21:05 UTC)
Report prepared by the U.S. Geological Survey.
NORTHERN MARIANAS VOLCANOES
No definitive signs of unrest were detected at any Northern Mariana Island volcanoes during the past week.
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, the following volcanoes have alert levels of UNASSIGNED: Anatahan, Sarigan, Farallon de Pajaros, Supply Reef, Maug, Asuncion, Agrigan, Pagan, Almagan, and Guguan.
For definitions of Aviation Color Codes and Volcano Alert Levels: https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes
SUBSCRIBE TO VOLCANO ALERT MESSAGES by email: http://volcanoes.usgs.gov/vns/
CNMI Homeland Security and Emergency Management
https://opd.gov.mp/library/agency/homeland-security-and-emergency-management.html
USGS Northern Mariana Duty Scientist (907) 786-7497
http://volcano.wr.usgs.gov/cnmistatus.php
Satellite information, Washington VAAC
http://www.ssd.noaa.gov/VAAC/washington.html