USGS Volcanoes: Notices released in the last day.

Lava continues to erupt slowly within the summit crater of Great Sitkin Volcano. Small earthquakes and rockfall events were detected but the volcano was seismically quiet over the past day. Satellite and web camera images were obscured by clouds over the past day.

The current lava eruption began in July 2021 and, since then, has 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.

Low-level unrest continues at the Atka volcanic complex characterized by weak seismic tremor. Satellite observations were obscured by clouds over the past day.

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.

Unrest continues at Shishaldin Volcano. Seismic and infrasound activity remains elevated over the past day.  A plume of sulfur dioxide gas was observed in satellite data from yesterday afternoon. Satellite and web camera views of the volcano were mostly obscured by clouds 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: 

• Episode 44 of the ongoing Halemaʻumaʻu eruption ended abruptly at 7:41 p.m. HST on April 9, 2026, after 8.5 hours of continuous lava fountaining. The eruption is currently paused.

• Tephra fell outside of the closed area of Hawaiʻi Volcanoes National Park along the north rim of Kaluapele (Kīlauea caldera) and in adjacent communities. Tephra as large as 10 inches (25 centimeters) was reported in the Volcano Golf Course subdivision, and fine ash and Peleʻs hair was reported as far away as Hilo. 

   

Episode 44 Chronology:

Episode 44 lava fountaining stopped at 7:41 p.m. HST on April 9, 2026, after 8 hours and 31 minutes of continuous lava fountaining from the north vent. The south vent never fountained during this episode, but it displayed periodic gas jetting and flames. The highest peak or instantaneous effusion rate of just over 500 cubic yards (390 cubic meters) per second occurred around 12:30 p.m. HST on April 9. Episode 44 saw an average effusion rate of 260 cubic yards (200 cubic meters) per second, with an estimated 7.5 million cubic yards (5.8 million cubic meters) of lava erupted and covering about 50% of the Halemaʻumaʻu crater floor. The Uēkahuna tiltmeter (UWD) recorded about 17.6 microradians of deflationary tilt during episode 44.

Episode 44 lava fountaining began at 11:10 a.m. HST on April 9, 2026, almost a week after the onset of precursory lava overflows on April 3. There were approximately 75 precursory overflows from April 3 to the start of episode 44 lava fountaining on April 9. Only 4 precursory overflows originated from the north vent, all on the morning of April 9. The last of these began at 10:08 a.m. HST and erupted continuously until transitioning into the onset of episode 44 at 11:10 a.m. HST. The start of episode 44 was marked by a sharp increase in seismic tremor and deflationary tilt recorded at the Uēkahuna tiltmeter (UWD). At first, the north vent grew slowly to about 330 feet (100 meters) in height by 12:00 p.m, then it reached a maximum of about 800 feet (240 meters) by 12:45 p.m. HST. Afterwards it gradually dropped, and by 4:00 p.m. it was 500 feet (150 meters) in height, then it further diminished until the end of the episode at 7:41 p.m. HST.

The single lava fountain produced significant heat and ash, feeding a plume that reached a maximum height of about 15,000 feet (4,500 meters) above sea level by 1:30 p.m. HST. Southerly winds directed the plume and tephra fall to the north of Halemaʻumaʻu.

This eruption was much smaller in size than episodes 41–43, but due to steady winds it produced a tephra fallout pattern similar to but not as thick as episode 43. The plume deposited tephra within Hawaiʻi Volcanoes National Park near Kīlauea Military Camp and into the adjacent Volcano Golf Course subdivision.

Alert levels were raised from ORANGE / WATCH to RED / WARNING by the USGS Hawaiian Volcano Observatory at 12:36 p.m. HST reflecting potential hazards to surrounding communities and aviation. Highway 11 through Volcano and the Kīlauea section of Hawaiʻi Volcanoes National Park were closed due to the hazards. The National Weather Service issued an ashfall WARNING at 12:40 p.m. HST following an earlier ashfall advisory. Ash and Pele’s hair was reported as far away as Kaumana, just west of Hilo.

Resources:

• Additional short messages during episodes: 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 
• Three Kīlauea summit livestream videos: https://www.youtube.com/@usgs/streams 
• Report tephra fall: https://hawaiiash.science/report_form 
• Hawaiʻi Volcanoes National Park Information https://www.nps.gov/havo/planyourvisit/conditions.htm
• County of Hawaii Hazard Impact Map: https://www.arcgis.com/apps/dashboards/5865229bcba74020992b372ef18b6f17

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 44 of the ongoing Halemaʻumaʻu eruption ended abruptly at 7:41 p.m. HST on April 9 after 9 hours of continuous lava fountaining. Due to reduced ground and aviation hazards, the USGS is dropping the Volcano Alert Level from WATCH to ADVISORY and the Aviation Color Code from RED to YELLOW. 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 

Episode 44 of lava fountaining in Halemaʻumaʻu at the summit of Kīlauea began at 11:10 a.m. HST on April 9 and continues at the time of this notice. 

As of 5:00 p.m. HST, Hawaiian Volcano Observatory webcams show that lava fountains are now reaching heights less than 150 meters (500 feet), with significantly less tephra fall reported downwind to the north-northeast. With the reduced ground hazard from tephra fall, the USGS is lowering the Volcano Alert Level for Kīlauea from WARNING to WATCH.

The National Weather Service reports that the plume from this eruption is currently reaching a maximum height of 10,000 feet (3,000 meters) above sea level. Accordingly, the Aviation Color Code for Kīlauea remains at RED.

• 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.
• Help 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 MKcam 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.

Activity Summary: 

• Episode 44 of the ongoing Halemaʻumaʻu eruption began at 11:10 a.m. HST on April 9 and continues at this time. Peak north vent lava fountain heights of approximately 800 feet (240 meters) were reached around 1:00 p.m. HST; fountain heights are presently about 700 feet (215 meters). The south vent has not been active so far during episode 44, though it produced significant precursory overflows that began on Friday, April 3.  
• As of 2:00 p.m. HST, the north vent lava fountain is still reaching about 700 feet in height and it is feeding a plume of ash and gas above. The plume is hitting strong southerly winds about 3,000 feet (1,000 meters) above ground level, and these winds are transporting a narrow band of gas and tephra to the north-northeast of Halemaʻumaʻu. Tephra fallout is strongest in the direction of Kīlauea Military Camp and the Volcano Golf Course subdivision, with pieces of lightweight reticulite up to 12 inches (30 centimeters) reported falling in these areas. Tephra fall has also been reported near Volcano House within Hawaiʻi Volcanoes National Park.
• The volcanic plume is moving northward and widening over a large section of east Hawaiʻi. These areas may expect fine ashfall consisting of Peleʻs hair and small glassy particles.
• The National Weather Service has issued an ashfall warning for much of east Hawaiʻi. The Hawaiʻi County Civil Defense Agency has closed Highway 11 through Volcano and the National Park Service has closed Hawaiʻi Volcanoes National Park due to falling tephra and sulfur dioxide (SO₂) gas. Both agencies have encouraged residents to remain inside with windows closed and to disconnect water catchment tanks if possible.

Resources:

• Additional short messages during episodes: 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 
• Three Kīlauea summit livestream videos: https://www.youtube.com/@usgs/streams 
• Report tephra fall: https://hawaiiash.science/report_form 
• Hawaiʻi Volcanoes National Park Information https://www.nps.gov/havo/planyourvisit/conditions.htm
• County of Hawaii Hazard Impact Map: https://www.arcgis.com/apps/dashboards/5865229bcba74020992b372ef18b6f17

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 44 of lava fountaining in Halemaʻumaʻu began at the summit of Kīlauea began at 11:10 a.m. HST on April 9 and continues as of this notice. 

The National Weather Service reports that the plume from this eruption is reaching 15,000 feet (4,500 meters) above sea level. North vent lava fountains are currently reaching 190 meters (625 feet) above ground level. Ground-level sensors near the eruptive vents indicate that winds are blowing from the south, which suggests that volcanic gas emissions and volcanic material may be distributed to the north and north-northeast from Halemaʻumaʻu. 

• 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.
• Help 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 MKcam 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.

Episode 44 of lava fountaining in Halemaʻumaʻu at the summit of Kīlauea began at 11:10 a.m. HST on April 9. 

Ground-level sensors near the eruptive vents indicate that winds are blowing from the south, which suggests that volcanic gas emissions and volcanic material may be distributed to the north from Halemaʻumaʻu. 

• 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 MKcam 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.

Activity Summary:

Over the past day, the Halemaʻumaʻu south vent has overflowed at least 20 times, with slightly increased vigor starting yesterday afternoon. These lava flows have been associated with gas piston tremor cycles in the vent, with limited spattering and low dome fountaining. There was a single overflow from the north vent early this morning, along with intermittent spattering. Gradual summit inflation and low-level seismic tremor have persisted through the past 24 hours. Overflows and spattering may continue until lava fountaining episode 44 begins, but periods of deflation and reduced vent activity may still occur and delay the onset of the next episode. The current forecast window for episode 44 is between now and April 15.

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

NOTES:

The National Weather Service (NWS) issued a Special Weather Statement yesterday about the potential for tephra fall from episode 44 in downwind communities, especially if the episode occurs in the next several days, when the NWS has forecast possible southerly winds.

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

Summit Observations:

The south vent in Halemaʻumaʻu crater has overflowed at least 20 times since yesterday morning's update; rainy, foggy conditions occluded webcam views for a multi-hour period midday yesterday, preventing an accurate count. Lava flow vigor increased slightly starting yesterday afternoon, with activity still confined to the southwestern portion of the crater floor. These overflows have been associated with gas piston tremor cycles in the south vent, with limited spattering and low dome fountaining. A single overflow from the north vent started around 2:25 a.m. HST this morning and lasted 10–20 minutes, though intermittent spattering has continued in the vent since then.

Seismic tremor is continuous with frequent small, poorly defined bursts possibly related to the rise and fall of magma within the vents. 

Following a two-day period of summit deflation starting Sunday, April 5, inflation returned to UWD tiltmeter On Tuesday, April 7, and continues at this time. UWD has now recorded about 25.4 microradians of inflationary tilt since the end of episode 43. After initially being affected by heavy rainfall on Tuesday, SMC tiltmeter began tracking the inflation yesterday morning.

During eruptive pauses like the one at present, the sulfur dioxide (SO₂) emission rate from the summit has varied within a typical range of 1,000 to 5,000 tonnes of SO₂ per day. Winds have been gusty out of variable directions between the south and west over the past 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:

Rapid rebound of tilt following episode 43 lava fountaining, continued tremor, visible glow, and precursory overflows from the eruptive vents suggest that another lava fountaining episode is likely soon. Continued overflows and associated spattering may be observed as the onset of episode 44 lava fountaining approaches; however, periods of deflation and reduced vent activity may still occur and delay the onset of the episode. Models based on summit inflation indicate that episode 44 lava fountains are likely to occur between now and April 15.

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

Recap of episode 43:

Episode 43 ended at 6:21 p.m. HST on March 10 after lava fountaining continued for just over 9 hours from both vents, sending tephra into surrounding communities. UWD tiltmeter recorded 33.9 microradians of deflationary tilt during the episode. A complete summary of activity can be found here. 

Resources:

NOTE: HVO’s monitoring network is mostly recovered from 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 south 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.

On April 8, 2026, high-resolution satellite imagery revealed a plume of discolored water near Ahyi Seamount, stretching approximately 300 to 400 meters (985 to 1,300 feet) across the surface. No signs of volcanic activity or unrest were detected in data from remote underwater pressure sensors, nor were there any other indicators suggesting significant unrest. The last time a similar plume was visible in satellite imagery was on January 9, 2026; however, persistent cloud cover and limited availability of high-quality satellite images have made it challenging to monitor such occurrences consistently.

There are no local monitoring stations near Ahyi seamount, which limits our ability to detect and characterize volcanic unrest there. We will continue to monitor satellite and distal hydroacoustic data for additional evidence for, or escalation of, volcanic activity.

NORTHERN MARIANAS VOLCANOES
No definitive signs of unrest were detected at any other Northern Mariana Island volcanoes during the past week. 

Monitoring of Northern Mariana Islands Volcanoes

Northern Mariana Island volcanoes are monitored using seismo-acoustic sensors on Saipan, and by examining satellite imagery. We also use distant seismic stations in Guam and Chichijima, Japan, and hydroacoustic data from Wake Island, when available. 

This level of monitoring can detect significant volcanic activity in the CNMI but cannot provide advanced 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.