USGS Volcanoes: Notices released in the last day.

Slow eruption of lava continues. Minor seismicity detected over the past day. Slightly elevated surface temperatures were observed in satellite data. Nothing was evident in web camera observations of the volcano.

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.

Seismic activity was detected during the past day. Cloud cover prevented clear satellite views of the volcano. Sulfur dioxide emissions were detected in TROPOMI satellite data.

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. 

Minor seismic activity and infrasound were detected at the volcano. Sulfur dioxide emissions drifting to the northwest were evident in satellite imagery. Nothing was observed in partly cloudy satellite and web camera views of the volcano over the past day.

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. 

Activity Summary: 

Lava fountaining episode 48 in Halemaʻumaʻu at the summit of Kīlauea began at 4:40 a.m. HST on June 1, 2026, after more than 90 overflow events from the south vent that started at 5:41 p.m. HST on May 30. 

Fountaining is focused at the north vent, and has reached more than 650 ft high (200 m). Seismic and deformation signals indcate that the fountain has reached its peak height and effusion rate for episode 48 already, although fountaining will likely continue for many more hours.

Webcams and radar indicate that the plume has reached 24,000 ft above sea level (7,300 m). Ground level winds are from the northwest and can potentially disperse tephra to the southwest in the Kau Desert and to Pāhala and even farther. Higher level winds at 10,000 to 20,000 ft above sea leve (3,000 to 6,000 m) are from the south and can potentially disperse tephra to the north and east into public overlooks in Hawaiʻi Volcanoes National Park and into communities around the national park.

The National Weather Service has issued an ash advisory for south and east Hawaiʻi.  WWA Summary by Location for 19.41N 155.29W with HIZ052/HIC001/HIZ338 emphasis Ashfall Advisory

Hawaiʻi County Civil Defense Agency has also released an ALERT notifiying residents to prepare for ash and tephra by closing windows and disconnecting catchment systems where possible. Everbridge - Mass Notification

Current Conditions:

Ash and tephra up to several inches (several centimeters) in diameter and strands of Pele's hair have been reported at the Uēkahuna overlook in Hawaiʻi Volcanoes National Park.

Tephra is also falling on Highway 11 near and west of the Nāmakanipaio campground between mile marker 32 and 34. 

Fine ash and Peleʻs hair has been reported from Volcano village, Mauna Loa Estates, and Ohia Estates to the northeast of Hawaiʻi Volcanoes National Park.

Sulfur dioxide gas has not been reported with this tephra fall. Satellite data show most of the gas is carried away in the high plume.

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 smog) 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 the links below:
  • https://seagrant.soest.hawaii.edu/resource-and-guidance-for-volcanic-tephra-fall/  
  • https://vog.ivhhn.org/sites/default/files/PelesHair_FAQs_v2.pdf
• 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.

Lava fountaining for episode 48 of the ongoing Halemaʻumaʻu eruption at the summit of Kīlauea started at 4:40 a.m. HST on June 1 and continues as of this notice. Activity is focused at the north vent with the fountain reaching over 500 to 650 feet above the vent.

The plume from this eruption is currently reaching 24,000 feet above sea level. Ground-level sensors near the eruptive vents indicate that winds are blowing from the northeast direction, and could potentially disperse tephra to the southwest. The National Weather Service indicates winds are from the south at 10,000 to 20,000 feet above sea level, and could potentially disperse tephra to the north.

Accordingly, HVO is leaving the Alert Level for Kīlauea at WATCH and the Aviation Color Code at ORANGE. 

Alert level and aviation color code definitions: https://www.usgs.gov/programs/VHP/alert-level-system. Another VAN will be published when lava fountaining for episode 48 reaches its peak height.

• All eruptive vents and lava flows are confined to Halemaʻumaʻu crater within Hawaiʻi Volcanoes National Park. Tephra fall from volcanic ash clouds is greatest within 3 miles (5 km) of the vents, lighter ash and Pele's Hair may stay suspended for large distances from the vents.
• Support science and community awareness by reporting tephra fall: https://hawaiiash.science/report_form 
• Three Kīlauea summit livestream videos that show eruptive lava fountains are available here: https://youtube.com/@usgs/streams 
• KPcam and MK2cam provide views of the plume height for aviation purposes
• Additional short updates as the episode progresses will be posted here: https://www.usgs.gov/observatories/hvo/observatory-messages 
• Timeline of eruptive episodes since December 23, 2024: https://www.usgs.gov/volcanoes/kilauea/science/eruption-information 

Most lava fountaining episodes since December 23, 2024, have continued for a day or less.

Lava fountaining for episode 48 of the ongoing Halemaʻumaʻu eruption at the summit of Kīlauea began at 4:40 a.m. HST on June 1 with activity focused at the north vent.

Ground-level sensors near the eruptive vents indicate that winds are blowing very lightly from the northeast direction. The National Weather Service has issued a Special Weather Statement indicating a potential for volcanic gas emissions and volcanic material to be carried by winds from the vents within Halemaʻumaʻu to the southwest at lower levels and to the east at higher levels in the atmosphere.  

WWA Summary by Location for 19.69N 155.5W with HIZ027/HIC001/HIZ342 emphasis Special Weather Statem…

Accordingly, HVO is leaving the Alert Level for Kīlauea at WATCH and the Aviation Color Code at ORANGE. 

Alert level and aviation color code definitions: https://www.usgs.gov/programs/VHP/alert-level-system. Another VAN will be published when lava fountaining for episode 48 reaches its peak height.

• All eruptive vents and lava flows are confined to Halemaʻumaʻu crater within Hawaiʻi Volcanoes National Park. Tephra fall from volcanic ash clouds is greatest within 3 miles (5 km) of the vents, lighter ash and Pele's Hair may stay suspended for large distances from the vents.
• Support science and community awareness by reporting tephra fall: https://hawaiiash.science/report_form 
• Three Kīlauea summit livestream videos that show eruptive lava fountains are available here: https://youtube.com/@usgs/streams 
• KPcam and MK2cam provide views of the plume height for aviation purposes
• Additional short updates as the episode progresses will be posted here: https://www.usgs.gov/observatories/hvo/observatory-messages 
• Timeline of eruptive episodes since December 23, 2024: https://www.usgs.gov/volcanoes/kilauea/science/eruption-information 

Most lava fountaining episodes since December 23, 2024, have continued for a day or less.

Summary

Yellowstone Caldera activity remains at background levels, with 45 located earthquakes in May (largest = M2.0). Deformation measurements indicate no significant uplift or subsidence of the caldera or north caldera rim since January 2026.

Recent Work and News

Echinus Geyser, in Norris Geyser Basin, remained active, with 2 eruptions in May.  The month also included eruptions of Black Diamond Pool in Biscuit Basin (site of a hydrothermal explosion in 2024) that were recorded by acoustic, seismic, and temperature measurements on May 5 and 11.  The biennial coordination meeting of the Yellowstone Volcano Observatory took place during May 18-20 at Mammoth Hot Springs, with discussions focusing on how to update geologic maps of the park and better anticipate and detect hazardous hydrothermal events.  Field work included the seasonal deployment of semipermanent GPS stations, which are temporary GPS sites that are set up every May and recovered in September/October and serve to densify the ground deformation monitoring network during summer months.

Seismicity

During May 2026, the University of Utah Seismograph Stations, responsible for the operation and analysis of the Yellowstone Seismic Network, located 45 earthquakes in the Yellowstone National Park region. The largest event of the month was a microearthquake of magnitude 2.0 located about 20 miles south-southeast of Mammoth Hot Springs in Yellowstone National Park on May 21 at 11:08 p.m. MDT.

There were no swarms identified during May.

Earthquake activity in Yellowstone is at background levels.

Ground Deformation

Data from continuous GPS stations indicate little net deformation in the region since January 2026.  The uplift that started in July 2025 on the north caldera rim ceased by mid-January 2026, and there has been no uplift or subsidence of Yellowstone Caldera since December 2025.

An example of GPS data can be found at http://www.unavco.org/instrumentation/networks/status/pbo/data/NRWY (click on Static Plots / Cleaned)