USGS Volcanoes: Notices released in the last day.

Minor earthquakes were detected over the past day, likely associated with rockfall on the growing dome. Clear satellite images indicated elevated surface temperatures on the growing lava dome. 

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.

A small explosion was detected in seismic and infrasound data 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 includes several vents, including Korovin Volcano, Mount Kliuchef and Sarichef Volcano. Korovin has been the site of most historical eruptions that typically produce minor amounts of ash and occasional but small lava flows. The Atka volcanic complex is monitored by local seismic and infrasound sensors and webcam, satellite data, and regional lightning detection instruments.

Low-level unrest continues with seismicity at low-levels. Clouds obscured satellite images.

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 signals were detected at the volcano. A sulfur dioxide plume was seen in satellite images drifting to the west, associated with continued degassing. 

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. 

A small explosion from Korovin Volcano was detected in seismic and infrasound data at 3:55 am AKDT (11:55 UTC) this morning, July 16, 2026. The Aviation Color Code and Alert Level are being raised to YELLOW/ADVISORY. No emissions were observed in satellite images, but regional clouds would obscure activity below 10,000 feet (3 km) asl. Possible ash clouds generated by such events are expected to be small and dissipate quickly. Fallout of ash, if any, is unlikely to extend much beyond the upper flanks of the volcano. 

Overview:

The summit eruption of Kīlauea in Halemaʻumaʻu is paused following 8.3 hours of lava fountaining during episode 51 on July15, 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. More data are needed to determine the forecast. 

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:

Bright glow and flames were visible overnight from both the north and south vents in Halema’uma’u. Numerous bright, shifting incandescent spots were visible overnight from lava flows that erupted onto the floor of Halema'uma'u crater and the slopes of the active vents during episode 51. Strong glow was visible from cracks and around the edges of these flows and from overturns and breakouts that exposed still-molten lava. Slow movements from cooling lava flows and gravity induced slumps on the vents are expected to continue in the coming days and nights. Degassing plumes from both vents are being blown toward the southwest this morning.

Low-frequency seismic pulsing began with the cessation of episode 51 and continues this morning, which is typical during the onset of pauses between eruptive episodes. There were two shallow earthquakes within Kaluapele (Kīlauea caldera) in the past 24 hours, the largest of which was a M2.0 beneath the southeast corner of Halemaʻumaʻu. 

Kīlauea summit deflation totaled 14.7 microradians during episode 51. Once the episode ended, inflation resumed and has since recovered 2.2 microradians of tilt at the summit tiltmeter at Uēkahuna (UWD).  

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 summit deflation to inflation at the end of episode 51 along with glow from the vents indicates that episode 52 fountaining is likely. More inflationary tilt data are needed to determine the forecast window.

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.

Activity Summary: 

• 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.

Episode 51 Chronology:

Lava fountaining episode 51 in Halemaʻumaʻu at the summit of Kīlauea began around 8:30 a.m. HST on July 15 and ended abruptly at 4:46 p.m. HST, after 8.3 hours of continuous fountaining from the north vent. The last 2-3 minutes were marked by gas jetting from the north vent. The south vent never fountained during this episode but did emit flames and gas jets. The instantaneous effusion rate peaked at about 370 cubic yards (280 cubic meters) per second at approximately 10:30 a.m. HST, with an average effusion rate of 200 cubic yards (150 cubic meters) per second for the entire fountaining episode. An estimated 6.6 million cubic yards (5.1 million cubic meters) of lava erupted and covered about 50% of the Halemaʻumaʻu crater floor. Seismicity followed the normal change in tremor patterns seen after most fountain episodes. There was one locatable earthquake associated with the eruption: a shallow magnitude-2 event at 14:52:59 HST located beneath the southeast corner of Halema'uma'u crater. The Uēkahuna tiltmeter (UWD) recorded about 14.7 microradians of deflationary tilt during episode 51.

Precursory activity began from the north vent on the afternoon of July 14 with 4 overflows between 3 and 4 p.m. HST, the longest lasting over 30 minutes. Activity then paused when inflation leveled off. Summit inflation resumed later in the evening. Overflows began from the south vent at 2:08 and 2:32 a.m. HST on July 15, and each lasted less than 5 minutes. After a brief pause, short overflows from the north vent occurred at 4:27 and 4:42 a.m. HST. These were immediately followed by the onset of a vigorous overflow fed by 10-30 foot (3-10 meter) high dome fountains from the north vent at 4:47 a.m. HST which continued until the onset of episode 51 fountaining around 8:30 a.m. HST. The transition was marked by increasing height of the dome fountain, greater eruptive volume, increased deflation and tremor.

The north vent lava fountain reached a peak height of approximately 950 feet (290 meters) around 10:30 a.m. HST and produced significant heat and ash, feeding a plume cloud that reached a maximum height of about 18,000 feet (5,500 meters) above sea level based on radar data reported by the National Weather Service (NWS) and verified by HVO webcam images. Winds were out of the northeast during the initial hours of fountaining and caused the plume to move toward the southwest during the most energetic part of the episode. High level winds from the south blew the upper plume toward the northwest after 10:00 a.m. HST. The NWS issued an updated Special Weather Statement (SWS) at 10:26 a.m. HST indicating that varying levels of ash, Pele`s hair, and other lightweight tephra may fall downwind of the eruption. The plume track largely remained within Hawaiʻi Volcanoes National Park with most tephra falling in the closed area.

Fountain and plume heights gradually decreased in height to about 400 feet (120 meters) AGL and 10,000 feet (3,000 meters) AMSL, respectively, by 4:40 p.m. HST. Then the episode ended abruptly at 4:46 p.m. HST. No tephra was reported from any populated areas.

The abrupt switch from summit deflation to inflation at the end of episode 51 indicate that another lava fountaining episode is likely.

Published Notices about episode 51: 

Volcano Activity Notice at end of episode 51: USGS Volcano Notice - DOI-USGS-HVO-2026-07-16T01:02:30+00:00

Volcano Activity Notice for maximum episode 51 fountain heights and reports of tephra fall in Hawai'i Volcanoes National Park: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-07-15T20:15:42+00:00

Hawaiʻi County Civil Defense Agency message alerting community to potential ash fall: https://evb.gg/n#ybjxxqeznxi/0lgoRWVn

HVO short messages posted to the HVO website and social media as episode 51 progressed: HVO - Observatory Messages | U.S. Geological Survey

Volcano Activity Notice when episode 51 began: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-07-15T01:41:41+00:00

Kilauea Daily Update for July 15 prior to the start of episode 51: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-07-15T15:48:14+00:00

Volcano Activity Notice issued on July 14 when precursory low-level eruptive activity before episode 51 began: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-07-15T01:00:23+00:00

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.

Episode 51 of the ongoing Halemaʻumaʻu eruption ended abruptly at 4:46 p.m. HST on July 15 after 8.1 hours of continuous lava fountaining. The eruptive plume was under 10,000 feet (3,000 m) above sea level when fountaining ended. Tephra that was carried high into the air during fountaining may remain suspended in the atmosphere for some time and may continue to fall even after lava fountaining ended. Additional details on this eruptive episode will be provided in the next official report.

• 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.
• Timeline of eruptive episodes since December 23, 2024: https://www.usgs.gov/volcanoes/kilauea/science/eruption-information 
• Three Kīlauea summit livestream videos are available here: https://www.youtube.com/@usgs/streams 
• Additional short updates shared during the episode can be found here: https://www.usgs.gov/observatories/hvo/observatory-messages 

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.

Signs of unrest at Ahyi Seamount have been observed in recent satellite images over the past few weeks. Small plumes of discolored water were observed drifting less than 0.3 miles (0.5 km) away from the volcano in satellite images on July 1, 7, and 11. Small plumes have been observed intermittently in clear satellite images over the last few months, but recent images show more discrete plume shapes suggesting more vigorous activity. No significant activity has been detected from the direction of Ahyi Seamount in hydroacoustic array data at Wake Island. 

The plumes are likely the result of gas release into the water column, these 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.

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. The Aviation Color Code and Volcano Alert Level are being raised to YELLOW and ADVISORY. We will continue to monitor satellite and distal hydroacoustic data for additional evidence for, or escalation of, volcanic activity.