ALASKA VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Friday, August 7, 2026, 11:12 AM AKDT (Friday, August 7, 2026, 19:12 UTC)
Lava continues to erupt slowly within the summit crater. A GNSS sensor on the northwest shore of the island continues to record deflation, consistent with pressure reduction at depth because of lava eruption at the summit. Satellite data shows that the lava dome is gradually expanding toward the east-southeast and slightly elevated surface temperatures were observed when cloud cover did not obscure the volcano. Seismic activity remains low, with only occasional small volcanic earthquakes and seismic signals associated with minor rockfalls detected.
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.
Low-level unrest continues at Mount Kupreanof. Earthquakes continue at a low rate. Robust steam emissions from the fumarole field on the southwest flank of Kupreanof were observed in web camera images and emissions of sulfur dioxide gas were observed in satellite data this past week.
A new temporary monitoring station was installed recently near Mount Kupreanof and is providing seismic data, infrasound data, gas measurements, and web camera images on an intermittent basis. This is by design to conserve battery power, but the frequency of data acquisition can be increased if activity warrants. The closest functioning seismometers that provide continuous data are approximately 10 miles (16 km) to the northeast 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.
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, characterized by numerous small earthquakes, persistent tremor, and frequent infrasound signals generated by small explosions within the volcanic conduit. During periods of clear weather, a robust a steam plume was observed in web camera and satellite images and sulfur dioxide gas emissions continue to be observed in satellite data.
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
Ronni Grapenthin, Acting Coordinating Scientist, UAFGI, rgrapenthin@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, August 7, 2026, 8:31 AM PDT (Friday, August 7, 2026, 15:31 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, Mount St. Helens, and Mount Hood. All monitoring data are consistent with background activity levels in the Cascade Range.
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
HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Friday, August 7, 2026, 11:26 AM HST (Friday, August 7, 2026, 21:26 UTC)
Overview:
The summit eruption of Kīlauea in Halemaʻumaʻu remains paused. Very slight, infrequent spatter was observed overnight within the north vent. Moderate to strong glow persisted at the north and south vents, while weak, intermittent glow was observed from the recently opened crack upslope of the south vent. Occasional small flames were detected, primarily at the south vent and less frequently at the north vent; neither flames nor spatter were associated with gas pistoning. This morning tilt meters began recording a deflationary trend, the second of this repose period. Current models indicate the forecast window for episode 53 remains between August 8 and August 12, but this window could be pushed back later if the deflation continues for an extended time period.
No significant activity has been noted along Kīlauea’s East Rift Zone or Southwest Rift Zone.
A summary of episode 52 is posted below.
NOTE: Significant changes in activity between Daily Updates are posted here: https://www.usgs.gov/observatories/hvo/observatory-messages
Summit Observations:
Moderate glow returned to the north and south vents yesterday evening and intensified overnight. Weak glow was initially visible from the cracks that opened upslope of the south vent but almost completely diminished by early morning. Periodic small flames were observed primarily at the south vent. Very slight spatter and occasional flames were first observed confined within the north vent around 8:00 p.m. HST yesterday and 4:30 to 5:00 a.m. HST this morning, with the strongest spatter occurring at 4:37 a.m. HST.
At approximately 7:00 a.m. HST yesterday, summit seismicity transitioned from irregular gas pistoning to more continuous tremor, which has persisted through this morning with recurring ragged spikes every 2–3 minutes. Three small (<M2.0) earthquakes occurred beneath eastern Halemaʻumaʻu crater at a depth of just over 4 miles (7 km).
Since the end of episode 52, the Uēkahuna (UWD) tiltmeter has recorded 11.9 microradians of inflationary tilt after earlier reaching a maximum of 12.3 microradians on UWD. UWD tilt flattened around 4:00 a.m. HST and has lost about 0.5 microradians since 6:00 a.m. HST. Deflationary tilt is continuing at this time. The total deflationary tilt measured at UWD during episode 52 was 14.4 microradians.
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. Winds are currently from the northeast, between 11-16 mph, with potential gusts as high as 25 mph. Degassing plumes from the new crack, north and south vents are currently being blown to the southwest.
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 summit deflation to inflation at the end of episode 52 along with glow from the vents indicates that episode 53 fountaining is likely. Inflationary tilt was interrupted by deflation from August 2 to 3. A second deflationary step began at 6:00 a.m. HST this morning and if it continues could extend the forecast window. Current tilt-based models have a forecast window for episode 53 fountains between August 8 and August 12. Adjustments may be necessary if the current deflationary trend continues for a prolonged time.
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 52:
A detailed account of episode 52 is given in the HVO Status Report issued on July 29: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-07-29T13:10:51+00:00
Tephra fall was restricted mostly to the closed area of Hawaiʻi Volcanoes National Park to the southwest of the active Halemaʻumaʻu vents.
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 MONTHLY UPDATE
U.S. Geological Survey
Thursday, August 6, 2026, 3:12 PM HST (Friday, August 7, 2026, 01:12 UTC)
No significant activity was detected at Ofu-Olosega volcano during the past month. The USGS National Earthquake Information Center reported no earthquakes of magnitude 2.5 or greater in the vicinity of the volcano.
Background: The islands of Ofu and Olosega in the Manuʻa Islands of eastern American Samoa, with a combined length of 6 kilometers (3.7 miles), are separated by a narrow strait. The islands are formed by two eroded, coalescing basaltic shield volcanoes whose slopes dip to the east and west. The Nuʻutele tuff cone, forming a small crescent-shaped island immediately off the west end of Ofu, is of Holocene age (less than 11,650 years). A submarine eruption occurred in 1866, 3 kilometers (1.9 miles) southeast of Olosega, along the Samoan Ridge between Olosega and Taʻu Island. From: https://volcano.si.edu/volcano.cfm?vn=244010.
More Information: https://www.usgs.gov/volcanoes/ofu-olosega
No significant activity was detected at Taʻū volcano during the past month. The USGS National Earthquake Information Center reported no earthquakes of magnitude 2.5 or greater in the vicinity of the volcano. A Global Positioning System (GPS) instrument on Taʻū Island recorded no significant deformation.
The FAGA broadband seismometer located on eastern Taʻū Island is currently out of service. The TAU broadband seismometer on western Taʻū Island remains operational.
Background: In the Manuʻa Islands of eastern American Samoa, Taʻū Island is the top of a shield volcano, most of which is beneath the ocean. The volcano has a summit caldera, though landslides have removed the southern part of the caldera. Two rift zones are present on Taʻū, one to the northeast and one to the northwest. The northwest rift zone aligns with the Samoan Ridge, a predominantly submarine feature that leads to the islands of Ofu and Olosega. This ridge was formed by volcanic activity associated with the Samoa hotspot, which is currently located at the Vailulu‘u seamount 40 kilometers (25 miles) east of Ta‘ū Island. A submarine eruption occurred in 1866 on the Samoan Ridge between Ta‘ū and Ofu-Olosega.
More Information: https://www.usgs.gov/volcanoes/ta-u-island
No significant activity was detected at Tutuila volcano during the past month. The USGS National Earthquake Information Center reported no earthquakes of magnitude 2.5 or greater in the vicinity of the volcano.
Background: Tutuila Island is an elongated and eroded group of five Pliocene-to-Pleistocene-aged volcanoes constructed along two or three rifts trending south-southwest to north-northeast. The Leone Volcanics, in the southernmost part of the island, represent the youngest eruption deposits. Eruptions occurred during the Holocene (less than 11,650 years ago) along a 5-kilometer (3-mile) north-to-south trending fissure, forming a group of initially submarine tuff cones and subsequent subaerial cinder cones that produced fresh-looking pāhoehoe lava flows. An ash layer overlying a cultural deposit in the southwestern part of the island was radiocarbon dated at 440 ± 200 CE (Addison et al., 2006). From: https://volcano.si.edu/volcano.cfm?vn=244020.
More Information: https://www.usgs.gov/volcanoes/tutuila-island
Additional Resources
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 MONTHLY UPDATE
U.S. Geological Survey
Thursday, August 6, 2026, 3:06 PM HST (Friday, August 7, 2026, 01:06 UTC)
Mauna Loa had a decrease in seismic activity compared to the previous month; a total of 57 earthquakes were detected in Mauna Loa's summit region during the July reporting period, after 94 in June. Most earthquakes occurred deep beneath the upper Southwest Rift Zone or broadly scattered around the upper flanks. Very few earthquakes occurred directly beneath Mokuʻāweoweo.
Data from Global Positioning System (GPS) instruments on Mauna Loa showed slight inflation across the summit region in the past month. Most GPS stations at the summit recorded small upward vertical motions while shifting radially away from the caldera in the horizontal direction. Oscillations between contraction and inflation patterns during non-eruptive periods are normal, but inflation has been the dominant trend since the 2022 eruption, with magma refilling the summit reservoir system.
Gas and temperature data from a station on Mauna Loa's Southwest Rift Zone indicate these values are at background levels, with little change relative to previous months.
HVO continues to closely monitor Mauna Loa and will issue another update in one month, or earlier, should conditions change significantly.
Background: Mauna Loa is the largest active volcano on our planet and covers half of the Island of Hawaiʻi. Eruptions tend to produce voluminous, fast-moving lava flows that can impact communities on the east and west sides of the island.
Mauna Loa eruptions typically start at the summit and, within minutes to months of eruption onset, can migrate into either the Northeast or Southwest Rift Zone, or radial vents on the northwest flank. Since its first well-documented eruption in 1843, the volcano has erupted 34 times with intervals between eruptions ranging from months to decades. Mauna Loa erupted most recently in 2022.
More Information:
No significant activity was detected at Hualālai volcano during the past month. Seismic activity remained low and was representative of background activity levels at the volcano. The continuously recording Global Positioning System (GPS) instrument on Hualālai has been offline since March 15, 2026; HVO field engineers will service the station within the next few months to bring it back online.
Background: Hualālai is the third most active volcano on the Island of Hawaiʻi and typically erupts two to three times per 1,000 years. It last erupted in 1801 and, more recently, had a damaging seismic swarm in 1929 that was probably the result of a shallow intrusion of magma. The volcano is monitored by a continuous GPS instrument and seismometer located southeast of the summit, as well as several instruments on the nearby flanks of Mauna Loa and Mauna Kea volcanoes. Key sites on Hualālai and western Mauna Loa are resurveyed using GPS receivers every few years to detect any changes in the volcano's shape.
More Information:
Hualālai volcano summary also available by phone: (808) 967-8877
Hualālai website: https://www.usgs.gov/volcanoes/hualalai
No significant activity was detected at Haleakalā volcano during the past month. HVO seismometers recorded one earthquake in the vicinity of the volcano. The continuously recording Global Positioning System (GPS) instrument on Haleakalā lost connection on July 13th. No significant deformation was recorded leading up to the outage. The station is owned and operated by researchers at the Pacific GPS Facility (PGF), as part of the Hawaii Institute of Geophysics and Planetology (HIGP), who will service the station within the next few months to bring it back online.
Background: The most recent eruption on Haleakalā was probably between A.D. 1480 and 1600. The volcano is monitored by a continuous GPS instrument and seismometer located near the southwest edge of the summit crater. Key sites on Haleakalā are resurveyed using GPS receivers every few years to detect any changes in the volcano's shape.
More Information:
Haleakalā volcano summary also available by phone: (808) 967-8877
Haleakalā website: https://www.usgs.gov/volcanoes/haleakala
No significant activity was detected at Mauna Kea volcano during the past month. Seismic activity remained low and was representative of background activity levels at the volcano. The continuously recording Global Positioning System (GPS) instrument on Mauna Kea, operated by NASA's Jet Propulsion Laboratory, recorded no significant deformation in the past month.
Background: Mauna Kea is a shield volcano in the post-shield stage; it last erupted about 4,600 years ago. Monitoring is conducted by one GPS instrument and three seismometers on the volcano, plus instruments on adjacent Kohala volcano and denser geodetic and seismic networks on the north flank of Mauna Loa volcano to the south. With a summit at 4,207 meters (13,803 feet) above sea level, Mauna Kea is the tallest mountain in the State of Hawaii, and it is the tallest mountain on Earth when measured from its base on the ocean floor.
More Information:
Mauna Kea volcano summary also available by phone: (808) 967-8877
Mauna Kea website: https://www.usgs.gov/volcanoes/mauna-kea
No significant activity was detected at Kamaʻehuakanaloa volcano (formerly Lōʻihi Seamount) during the past month. Seismic activity remained low and was representative of background activity levels at the volcano.
Background: Intermittent earthquake activity has been recorded in the vicinity of Kamaʻehuakanaloa (formerly Lōʻihi Seamount) since as early as 1952. The most energetic earthquake sequence occurred in July–August 1996, which included more than 4,000 earthquakes, with nearly 300 events larger than M3.0 and 95 events in the M4.0 to 4.9 range. More recently, a swarm of 100 earthquakes occurred on May 11, 2020, with 18 events in the M3.0 to 3.9 range. There are no working monitoring instruments on Kamaʻehuakanaloa, whose peak is about 1,000 meters (3,280 feet) below sea level. All real-time information about the volcano is derived from land-based seismometers on the Island of Hawai‘i.
More Information:
Kamaʻehuakanaloa website: https://www.usgs.gov/volcanoes/kama'ehuakanaloa
Hawaiian Volcanoes at Elevated Alert Levels:
Kīlauea Volcano (YELLOW/ADVISORY) updates: https://www.usgs.gov/volcanoes/kilauea/volcano-updates
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