USGS Volcanoes: Notices released in the last day.

Slow eruption of lava likely continues within the summit crater. 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 minor rockfalls within the crater. 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 and infrasound sensors, satellite data, and web cameras, and regional infrasound and lightning networks.

Occasional earthquakes with magnitudes below 2.0 continue near Kupreanof Volcano, though they are difficult to locate with regional seismometers. Sulfur dioxide gas emissions were detected in a satellite image on May 29. Steam emissions were observed in a high spatial resolution satellite image on June 4, which is typical for this volcano.

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. 

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 emissions were observed in 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.

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, Mount Hood and Newberry. All monitoring data are consistent with background activity levels in the Cascade Range. Field crews were at Mount Rainier and Mount Hood this week performing maintenance on monitoring stations.

Overview:

The summit eruption of Kīlauea in Halemaʻumaʻu remains paused following 9 hours of lava fountaining during episode 48 on June 1, 2026. Tiltmeters around the summit of Kīlauea have measured inflation since the end of episode 48, indicating that an episode 49 is likely; forecast models indicate that the onset of fountaining episode 49 is 9-14 days from now. Glow was visible at the vents overnight and robust degassing plumes are visibly emanating from both vents in Halemaʻumaʻu during the day. 

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:

Bright and continuous glow was visible from the south vent in Halemaʻumaʻu overnight, with intermittent glow visible from the north vent. Robust degassing plumes are visibly emanating from both vents in Halemaʻumaʻu during the day. 

No earthquakes were detected beneath Kaluapele (Kīlauea caldera) within the past 24 hours. Low-frequency seismic pulsing continues to be recorded in Kīlauea summit region, appearing weaker over the past 24 hours compared to the previous days. This signal is typical during the pauses between eruptive episodes and may be associated with gas-pistoning. 

The UWD tiltmeter located near Uēkahuna at Kīlauea summit recorded a total of 17.1 microradians of deflationary tilt during episode 48. Once the episode ended, inflation resumed and UWD has since recovered 7.6 microradians of inflationary tilt. 

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. 

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 continued at the end of episode 48 and indicates that an episode 49 is likely. Forecast models based on Kīlauea summit region inflation rates suggest that the start of fountaining episode 49 is 9-14 days away.

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 48:

A detailed account of episode 48 is given in the HVO Status Report Issued June 1: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-06-02T00:33:02+00:00

• Episode 48 of the ongoing Halemaʻumaʻu eruption began at the summit of Kīlauea at 4:40 a.m. HST and ended abruptly at 1:37 p.m. HST on June 1, 2026, after 9 hours of continuous lava fountaining from the north vent. Lava fountains reached a maximum height of almost 650 ft (200 m) and lava flows covered 40% of the crater floor. The eruption is currently paused.
• The Halemaʻumaʻu eruption now has the most fountaining episodes ever recorded for an episodic fountaining eruption, edging out the Pu‘u‘ō‘ō eruption which had 47 fountain episodes. Other eruptions have had additional episodes related to changes in vent activity and location, this only applies to episodic fountains.
• Most tephra fell within the closed area of Hawaiʻi Volcanoes National Park, but sparse reticulite up to 1 inch (2 centimeters) in size fell at both the Uēkahuna overlook and on Highway 11 west of Nāmakanipaio campground. Fine ash and Peleʻs hair was reported from Hawaiʻi Volcanoes National Park in communities to the northeast, including Mauna Loa Estates, Ohia Estates, Volcano village, and Royal Hawaiian Estates.

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:

• 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
• Short messages tracking the evolution of the lava fountains and eruptive activity can be found here: https://www.usgs.gov/observatories/hvo/observatory-messages
• Three Kīlauea summit livestream cameras 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.

• Volcanic Gas: high levels of volcanic gas—primarily water vapor (H₂O), carbon dioxide (CO₂), and sulfur dioxide (SO₂)—are continually released during an eruption. Emissions can remain locally hazardous in the areas immediately downwind of the vents, even when the vents are not actively erupting. SO₂ reacts in the atmosphere to create vog (volcanic air pollution) downwind. SO₂ and vog may cause respiratory and other problems at high concentrations. 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: lava on the floor of Halemaʻumaʻu crater and the southwest side of Kaluapele, Kīlauea's summit caldera, remains hot and may slowly move in the days immediately following an eruptive episode.

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.

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

Typhoon Sinlaku has caused extensive destruction to the infrastructure on the island of Saipan. All data feeds from seismic and acoustic sensors on the island are now unavailable, and there are no ground-based instruments to detect significant explosive activity in the region, should it occur. It is unknown when connections to these sensors will be restored.

The USGS will continue to monitor satellite images and distant hydroacoustic and seismic sensors for any signs of volcanic activity in the CNMI. This level of monitoring can detect significant volcanic activity but cannot provide advance 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.