USGS Volcanoes: Notices released in the last day.

Slow lava effusion continues within the Great Sitkin summit crater. Over the past day, seismic data recorded frequent rockfalls from the growing lava dome. Web camera and satellite views were mostly cloudy but moderately elevated surface temperatures were observed in several partly cloudy satellite views.  

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.

Unrest persists at Shishaldin Volcano, with seismic and infrasound activity remaining elevated over the past day. Satellite data detected a sulfur dioxide gas plume. Nothing unusal was observed in cloudy to partly cloudy satellite and web camera views.    

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. 

Seismic activity, sulfur dioxide emissions, and thermal anomalies at Korovin Volcano (located within the Atka Volcanic Complex) have declined over the past couple weeks and are now at background levels. The Aviation Color Code and the Alert Level for the Atka Volcanic Complex are being lowered to GREEN/NORMAL. Small explosive events can occur at Korovin Volcano without significant precursory unrest. Fallout of ash from such events is unlikely to extend beyond the upper flanks of the volcano.   

Slow lava effusion continues within the Great Sitkin summit crater. Over the past day, seismic data recorded frequent rockfalls from the growing lava dome. Cloud cover obscured web camera and satellite views.

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.

Unrest persists at Shishaldin Volcano, with seismic and infrasound activity remaining elevated over the past day. Satellite data detected a sulfur dioxide gas plume, but satellite views of the volcano have been obscured by clouds. Most web camera views were cloudy but a single clear image showed a typical degassing plume from the summit.  

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. 

Low-level unrest persists at the Atka volcanic complex, marked by ongoing seismic tremor.  Satellite views were cloudy.  

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.

Monitored CALIFORNIA VOLCANOES
Current Volcano Alert Level: all NORMAL
Current Aviation Color Code: all GREEN

Activity Update: All volcanoes monitored by CalVO show normal background earthquake activity and deformation. Monitored volcanoes include Mount Shasta, Medicine Lake Volcano, Lassen Volcanic Center, Clear Lake Volcanic Field, Long Valley Volcanic Region, Coso Volcanic Field, Ubehebe Craters, and Salton Buttes.

Past Week Observations for April 06 (0000h PDT) to April 12 (2359h PDT):

Typical seismicity was recorded at The Geysers geothermal field south of the Clear Lake Volcanic Field; 102 earthquakes greater than M1 were recorded, with the largest having a magnitude of M2.8.

One earthquake greater than M1 was recorded in the Sierra Nevada Block, south of Mammoth Mountain and Long Valley, with a magnitude of M1.3.

One earthquake greater than M1 was recorded near the Salton Buttes, with a magnitude of M2.1.

Overview:

The Halemaʻumaʻu eruption of Kīlauea is paused. Glow from the south vent continued over the past day, along with incandescence on the crater floor as episode 44 lava flows cool and solidify. Many Kīlauea monitoring data streams are presently offline due to an outage of HVO's radio telemetry network, but the remaining operational stations are sufficient to detect any major changes in the volcanic system; none are noted at this time. Data from two tiltmeters are available, and forecasting suggests that Halemaʻumaʻu lava fountaining episode 45 will occur sometime between Sunday, April 19 and Sunday, April 26.

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

For more information on the partial monitoring network outage, see the Information Statement here: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-04-12T15:47:48+00:00

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

Summit Observations:

Overnight, glow was periodically visible at the Halemaʻumaʻu south vent, while none was apparent at the north vent. Episode 44 lava flows on the crater floor retain spots of incandescence as they cool and solidify, which may continue for a few more days. Lava fountaining episode 44 occurred on April 9.

Yesterday evening, another seismometer near Kīlauea summit was brought back online. Its data show continued low-level seismic tremor during the ongoing eruptive pause, with bursts every 5–15 minutes likely associated with gas pistoning cycles in the eruptive vents.

One HVO tiltmeter—station SMC located southeast of Kaluapele (Kīlauea caldera)—is transmitting data at this time; since the end of lava fountaining episode 44 on April 9, this instrument has tracked approximately 11.4 microradians of inflationary tilt, after recording 22.6 microradians of deflationary tilt in total during the episode. Yesterday afternoon, recent data was manually downloaded from the UWD tiltmeter located northwest of Kaluapele, and it showed no significant discrepancies with SMC.

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. Winds near the eruptive vents have been directionally variable over the past day.

Rift Zone Observations:

Rates of seismicity remain low in the East Rift Zone and Southwest Rift Zone.

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. Models based on summit inflation indicate that episode 45 lava fountains are likely to occur sometime between Sunday, April 19 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 deflation and SMC tiltmeter recorded 22.6 microradians of deflation 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:

• 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.