ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Monday, April 20, 2026, 11:59 AM AKDT (Monday, April 20, 2026, 19:59 UTC)
Slow lava effusion continues within the Great Sitkin summit crater. Over the past day, seismic data recorded rockfalls from the growing lava dome. Web camera and satellite views were cloudy.
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.
To view monitoring data and other information about Great Sitkin: https://avo.alaska.edu/volcano/great-sitkin
Unrest persists at Shishaldin Volcano, with seismic activity remaining elevated over the past day. Satellite and web camera views were mostly cloudy, though sulphur dioxide emissions were detected in one satellite image.
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.
To view monitoring data and other information about Shishaldin: https://avo.alaska.edu/volcano/shishaldin
Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497
David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460
Contact AVO: https://avo.alaska.edu/contact
The Alaska Volcano Observatory is a cooperative program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys.
Precursory low-level activity for episode 45 of the ongoing Halemaʻumaʻu eruption at the summit of Kīlauea began around 7:46 p.m. HST on April 20, 2026, with several overflows of lava from the north vent. Accordingly, HVO is raising the Alert Level for Kīlauea from ADVISORY to WATCH and the Aviation Color Code from YELLOW to ORANGE. Alert level and aviation color code definitions: https://www.usgs.gov/programs/VHP/alert-level-system.
Low-level precursory activity can continue for hours to days before Kīlauea summit lava fountaining begins. The forecast for lava fountaining episode 45 to start is between April 21-26. Another VAN will be published when lava fountaining begins.
Most lava fountaining episodes since December 23, 2024, have continued for a day or less.
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 air pollution) 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 https://seagrant.soest.hawaii.edu/resource-and-guidance-for-volcanic-tephra-fall/
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.
HVO continues to closely monitor Kīlauea and will issue additional notices as needed based on activity. Regularly scheduled daily updates for Kīlauea are posted on the HVO website at https://www.usgs.gov/volcanoes/kilauea/volcano-updates
More Information:
Subscribe to these messages: https://volcanoes.usgs.gov/vns2/
Summary of volcanic hazards from eruptions: https://www.usgs.gov/observatories/hvo/hazards
Recent earthquakes in Hawaiʻi (map and list): https://www.usgs.gov/observatories/hvo
Explanation of Volcano Alert Levels and Aviation Color Codes: https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes
WMPA01 PHVO 210716
VONA
DTG: 20260421/0716Z
VOLCANO: KILAUEA 332010
PSN: N1925 W15517
AREA: HAWAII
SOURCE ELEV: 4091FT AMSL
NOTICE NR: 2026/20
CURRENT COLOUR CODE: ORANGE
PREVIOUS COLOUR CODE: YELLOW
SVO: HAWAIIAN VOLCANO OBSERVATORY
ACT STS: ERUPTION ONGOING
ONSET: UNKNOWN
DUR: ONGOING EPISODIC
VA CLD HGT: UNKNOWN
HGT SOURCE: NO VA CLD PRODUCED
MOV: UNKNOWN
CTC: HVO DUTY SCIENTIST: 808-785-3144
RMK: LOW-LEVEL ERUPTION OF LAVA BEGAN AT THE SUMMIT OF KILAUEA AT 7:46 PM ON APRIL 20,
2026. LOW-LEVEL ACTIVITY CAN CONTINUE FOR HOURS TO DAYS BEFORE THE LAVA FOUNTAINING
EPISODE BEGINS. LAVA FOUNTAIN EPISODE 45 IS FORECAST TO START BETWEEN APRIL 21-26.
NXT NOTICE: A NEW VONA WILL BE ISSUED IF COND CHANGE SIGNIFICANTLY OR IF THE COLOR CODE CHANGES
NNNN
HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Monday, April 20, 2026, 7:53 AM HST (Monday, April 20, 2026, 17:53 UTC)
Overview:
The summit eruption of Kīlauea in Halemaʻumaʻu is paused. Overall summit region inflation has continued since the end of episode 44 on April 9, with continued inflation over the past 24 hours. Strong and continuous glow, with frequent flames, have continued to be visible at the south vent overnight, as well as intermittent glow at the north vent. Forecast models currently suggest that lava fountaining episode 45 will occur sometime between Tuesday, April 21, and Sunday, April 26.
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:
Glow was consistently visible at the Halemaʻumaʻu south vent overnight, along with prolonged periods of intense flaming—likely caused by the ignition of volcanic gases escaping the vent. The north vent continues to emit volcanic gases, and intermittent glow was visible there overnight.
Low-level seismic tremor continues during the ongoing eruptive pause, and three small-magnitude earthquakes were recorded in Kīlauea summit region in the past 24 hours. Since the end of lava fountaining episode 44 on April 9, the Uēkahuna tiltmeter (UWD) has tracked approximately 14.9 microradians of inflationary tilt, with 2 microradians of inflationary tilt in the past 24 hours. This instrument recorded 17.6 microradians of deflationary tilt in total during the episode.
With the eruption paused, the sulfur dioxide (SO2) emission rate from Halemaʻumaʻu is likely now varying within a typical range of 1,000 to 5,000 tonnes per day. For the past few days, winds near the eruptive vents have been steady out of the northeast in the mornings before transitioning to more variable directions in the afternoons and evenings.
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 rapid return of inflationary tilt and glow from the Halemaʻumaʻu eruptive vents indicates that another lava fountaining episode is likely. Lava spattering and overflows from one or both of the eruptive vents are expected to precede the next lava fountaining episode. Forecast models based on summit inflation currently indicate that episode 45 lava fountains are likely to occur sometime between Tuesday, April 21, and Sunday, April 26.
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 44:
Episode 44 ended at 7:41 p.m. HST on April 9 after 8.5 hours of continuous lava fountaining from the north vent, sending tephra to the north into public areas of Hawai'i Volcanoes National Park and into surrounding communities. UWD tiltmeter recorded 17.6 microradians of deflationary tilt during the episode.
A full summary of episode 44 can be found in a Status Report here: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-04-10T06:25:16+00:00
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 south of the caldera.
The following links provide more information about the current eruption that began on December 23, 2024:
Hazards:
This episodic eruption is occurring within a closed area of Hawai'i Volcanoes National Park.
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.
More Information:
The Hawaiian Volcano Observatory is one of five volcano observatories within the U.S. Geological Survey and is responsible for monitoring volcanoes and earthquakes in Hawaiʻi and American Samoa.
Subscribe to these messages: https://volcanoes.usgs.gov/vns2/
Summary of volcanic hazards from eruptions: https://www.usgs.gov/observatories/hvo/hazards
Recent earthquakes in Hawaiʻi (map and list): https://www.usgs.gov/observatories/hvo
Explanation of Volcano Alert Levels and Aviation Color Codes: https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes