ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Saturday, May 23, 2026, 10:03 AM AKDT (Saturday, May 23, 2026, 18:03 UTC)
Small earthquakes associated with lava dome growth and rockfalls were detected in seismic data. Overnight satellite images indicated slightly elevated surface temperatures, consistent with slow lava advance. Webcam images of the volcano were obscured by clouds.
The current eruption began in July 2021 and, since then, lava flows have 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, webcams, and regional infrasound and lightning networks.
To view monitoring data and other information about Great Sitkin Volcano: https://avo.alaska.edu/volcano/great-sitkin
Seismic and infrasound sensors continue to detect frequent small events. Steam emissions were visible in clear webcam images, and sulfur dioxide was detected in satellite images drifting east from the volcano.
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 lightning data, and satellite images to detect eruptions.
To view monitoring data and other information about Shishaldin Volcano: https://avo.alaska.edu/volcano/shishaldin
A few small earthquakes were detected with regional seismic stations over the last day. Satellite images were obscured by clouds.
There is no real-time geophysical monitoring network at Mount Kupreanof. The closest functioning seismometers are 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, remote infrasound and lightning networks, and visual observations from pilots and mariners passing by the volcano.
To view monitoring data and other information about Mount Kupreanof: https://avo.alaska.edu/volcano/kupreanof
Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497
Pavel Izbekov, Acting Coordinating Scientist, UAFGI peizbekov@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.
ALASKA VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Friday, May 22, 2026, 11:49 AM AKDT (Friday, May 22, 2026, 19:49 UTC)
A satellite radar image on May 18 confirmed that lava continues to slowly advance to the east in the summit crater at Great Sitkin Volcano. Other satellite and webcam images were obscured by clouds. Seismic activity remains low, with occasional small volcanic earthquakes and signals from minor rockfalls within the crater.
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 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.
Earthquakes over the last week were generally small (less than magnitude 2.0) and most were not strong enough to determine locations using regional seismometers. Clouds obscured satellite images of the volcano's surface, but sulfur dioxide gas emissions were observed on one day.
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, as indicated by numerous small earthquakes, frequent infrasound signals, and volcanic tremor recorded during the week. Clouds obscured all satellite and webcam images of the volcano's surface throughout the week. Elevated sulfur dioxide gas emissions were detected in satellite data on most days.
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.
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.
HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Saturday, May 23, 2026, 9:14 AM HST (Saturday, May 23, 2026, 19:14 UTC)
Overview:
The Halemaʻumaʻu eruption of Kīlauea is paused. Glow was visible from both eruptive vents overnight. Summit reinflation has resumed after a brief deflation continuing the trend since lava fountaining episode 47 ended on May 15. Forecast models suggest that episode 48 will occur sometime between Sunday, May 24 and Tuesday, May 26. The M6.0 earthquake on the west side of the island last night did not impact activity at Kīlauea but did offset tiltmeters.
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:
Glow was visible from both Halemaʻumaʻu eruptive vents overnight, though it was brighter at the south vent. HVO geologists on a helicopter overflight yesterday morning observed active lava deep within both the north and south vents.
Low-level seismic tremor continues during the current pause, and has fluctuated over the past day. Earthquake activity beneath Kīlauea summit is low at this time.
Kilauea summit inflation continues. The M6.0 earthquake last night on the west side of the island caused shaking and a small instrumental offset in the tiltmeter data. This morning the inflation rate is steady but at a lower rate compared to earlier in the week. Since the end of lava fountaining episode 47 on May 15, the Uēkahuna tiltmeter (UWD) has tracked about 13 microradians of inflationary tilt. This instrument recorded 15.6 microradians of deflationary tilt during episode 47.
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 are steady out of the northeast at the summit this morning.
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 rapid return of inflationary tilt and glow from both Halemaʻumaʻu eruptive vents indicates that another lava fountaining episode is likely. Lava spattering and overflows from one or both of the eruptive vents are expected to precede the next lava fountaining episode. Forecast models based on summit inflation indicate that episode 48 is likely to occur sometime between Sunday, May 24 and Tuesday, May 26. The forecast window may change as more data are incorporated into the models, and possible periods of slowed inflation or even deflation may delay the onset of episode 48.
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
Recap of episode 47:
Episode 47 ended abruptly at 12:27 a.m. HST on May 15 after 9 hours of continuous lava fountaining from the north vent. The eruptive plume sent light tephra into public areas of Hawai'i Volcanoes National Park and surrounding communities to the northeast. UWD tiltmeter recorded 15.6 microradians of deflation during the episode.
A full summary of episode 47 can be found in a Status Report here: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-05-15T10:42:06+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
HAWAIIAN VOLCANO OBSERVATORY INFORMATION STATEMENT
U.S. Geological Survey
Friday, May 22, 2026, 10:42 PM HST (Saturday, May 23, 2026, 08:42 UTC)
HAWAIIAN VOLCANO OBSERVATORY INFORMATION STATEMENT
On Friday, May 22, 9:46 p.m. HST, a magnitude-6.0 earthquake occurred 7 mi (12 km) south of Hōnaunau-Nāpōʻopoʻo on the Island of Hawaiʻi at a depth of 14 mi (22 km) below sea level. The earthquake had no apparent impact on either Mauna Loa or Kīlauea volcanoes.
The depth, location, and recorded seismic waves of the earthquake suggest that it was caused by stress due to bending of the oceanic plate from the weight of the Hawaiian island chain; the earthquake was not directly related to volcanic processes. Strong to very strong shaking was reported on the west side of the Island of Hawaiʻi during the earthquake that happened this evening and could have resulted in light to moderate damage to infrastructure. Please report any observed damage to the County of Hawaiʻi Civil Defense Agency. Several aftershocks from the earthquake that happened this evening have already occurred. Most have been smaller than magnitude-3. Aftershocks may continue to occur in the coming days but are unlikely to be large enough to be felt or cause damage. We appreciate the more than 2,500 residents and visitors who submitted felt reports to the USGS website for this event; such reports help USGS and other responding agencies to understand the affected area and potential impacts of earthquakes.
The USGS Hawaiian Volcano Observatory continues to monitor Hawaiian volcanoes for any changes.
EARTHQUAKE DESCRIPTION
EARTHQUAKE INTENSITY AND AFFECTED AREA
EARTHQUAKE MAPS AND ADDITIONAL 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