USGS Volcanoes: Notices released in the last day.

Slow eruption of lava continues within the summit crater. Typical slightly elevated surface temperatures were observed throughout the week when cloud cover was not obscuring the volcano. Satellite radar images confirmed the lava dome continues to slowly expand to the east-southeast. Seismic activity remains low, with occasional small volcanic earthquakes and seismic signals from minor rockfalls observed. 

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.

A small explosion was detected in seismic and infrasound data on July 16 at 3:55 am AKDT (11:55 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 significant precursory unrest. No emissions were detected associated with this activity and elevated seismicity declined immediately after the event. 

The Atka volcanic complex is monitored by local seismic and infrasound sensors and webcam, satellite data, and regional lightning detection instruments. 

Earthquake activity continues near Mount Kupreanof volcano, with all magnitudes under 2.0 this week. 

There is no real-time geophysical monitoring network at Mount Kupreanof. The closest functioning seismometer is approximately 10 miles (16 km) to the northeast of the volcano as part of the Mount Veniaminof network. However, this week field teams began work to install a temporary monitoring station near the volcano with seismic, infrasound, gas monitoring, and a webcam. 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 and webcams showed steaming 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.

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 St. Helens and Mount Rainier. All monitoring data are consistent with background activity levels in the Cascade Range.

Overview:

The summit eruption of Kīlauea in Halemaʻumaʻu is paused following 8.3 hours of lava fountaining during episode 51 on July 15, 2026. Inflation measured by tiltmeters around the summit of Kīlauea resumed after episode 51 ended accompanied by continued glow from both vents, suggesting that another episode is likely. Preliminary models indicate that the forecast window for episode 52 is between July 24 and August 3. 

No significant activity has been noted along Kīlauea’s East Rift Zone or Southwest Rift Zone.

A summary of episode 51 is posted below.

NOTE: The V1 camera is on a temporary assignment to watch an area that has displayed persistent subsidence after several fountain episodes. It will return to its "normal" job of keeping an eye on the north vent when the current assignment is completed.

NOTE: Significant changes in activity between Daily Updates are posted here: https://www.usgs.gov/observatories/hvo/observatory-messages

Summit Observations:

Continuous strong glow was visible overnight from the south vent, with intermittent and variable glow from the north vent. Occasional flames were visible at both vents overnight. Some incandescent spots from the cooling episode 51 lava flows remained visible overnight on the floor of Halema'uma'u crater but were much weaker than the previous night. 

Low-frequency seismic pulsing, related to gas piston activity in the north vent, began with the cessation of episode 51 and continues this morning, which is typical during the onset of pauses between eruptive episodes. There were six shallow earthquakes around Kīlauea summit in the past 24 hours, the largest of which was a M2.2. 

Since episode 51 ended, inflation resumed and has recovered 4 microradians of tilt at the summit tiltmeter at Uēkahuna (UWD).  Kīlauea summit deflation totaled 14.7 microradians during episode 51. 

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. Degassing plumes from both vents are being blown toward the southwest 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 abrupt switch from summit deflation to inflation at the end of episode 51 along with continued glow from the vents indicates that another fountaining episode is likely. Preliminary inflation-based models have a forecast window for episode 52 from July 24 through August 3.

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 51:

A detailed account of episode 51 is given in the HVO Status Report issued on July 15: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-07-16T03:55:25+00:00

• Episode 51 of the ongoing Halemaʻumaʻu eruption began around 8:30 a.m. HST on July 15 and ended abruptly at 4:46 p.m. HST on July 15, 2026.
• The maximum lava fountain height was approximately 950 feet (290 meters) above ground level from the north vent. The south vent never fountained during this episode but did emit flames and gas jets.
• The maximum plume height was approximately 18,000 (5,500 meters) above mean sea level.
• Tephra fall was restricted mostly to the closed area of Hawaiʻi Volcanoes National Park to the southwest of the active Halemaʻumaʻu vents. A light fall of Peleʻs hair was reported at several sites in the national park outside the closed area, including Uēkahuna overlook and Kaʻu Desert trailhead on Highway 11.

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.

A 1000 ft-long (200 m) plume of discolored water was observed in the water above Ahyi Seamount in a satellite image on July 11. This and other plume images in the last few weeks are likely the result of gas release into the water column. This activity could reflect vigorous hydrothermal degassing or be associated with an ongoing effusive eruption. In either case, the observations indicate increased volcanic unrest and potential for activity to breach the ocean surface. In response, the Aviation Color Code and Volcano Alert Level were raised to YELLOW and ADVISORY on July 16.

Eruptive activity at Ahyi Seamount may present a hazard to mariners in the water above and near the volcano. The summit has shallowed over the course of previous eruptions to 180 feet (55 m) below sea level, but the lack of local real-time data means we are unable to forecast or warn of impending eruptions. We will continue to monitor satellite and distal hydroacoustic data for additional evidence for, or escalation of, volcanic activity.