Volcano Updates

CORRECTION:  The ash cloud from this morning’s eruption detached from the volcano around 07:00 AKDT (15:00 UTC) and is drifting east-southeast at an altitude of 38,000 ft above sea level. 

Activity at Shishaldin Volcano has declined significantly. Seismicity decreased rapidly around 06:00 AKDT (14:00 UTC) and no significant ash emissions from the volcano are being observed in satellite data at this time. In response, AVO is lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. 

The ash cloud from this morning’s eruption detached from the volcano around 07:00 AKDT (15:00 UTC) and is drifting east-southeast at an altitude of 38,000 ft above sea level.  Ash emissions continued at a lower altitude of about 20,000–25,000 ft above sea level until about 08:20 AKDT (16:20 UTC). Small explosions are currently being detected in infrasound data and likely represent low-level eruptive activity near the vent area.

Trace to minor amounts of ashfall were reported by the communities of False Pass, King Cove, Cold Bay and Sand Point.  Ashfall occurred during rainfall in all four communities. No ashfall is expected from the current small explosions that are being detected in infrasound. Refer to the National Weather Service SIGMET for the drifting ash cloud (https://www.weather.gov/aawu/sigmets) and the Ashfall Advisory and Special Weather Statement for trace to minor amounts of ashfall on communities on the lower Alaska Peninsula and surrounding waters (https://www.weather.gov/afc/).

Based on previous eruption cycles, pyroclastic flows and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

Activity at Shishaldin Volcano has declined significantly. Seismicity decreased rapidly around 06:00 AKDT (14:00 UTC) and no significant ash emissions from the volcano are being observed in satellite data at this time. In response, AVO is lowering the Aviation Color Code to ORANGE and the Alert Level to WATCH. 

The ash cloud from this morning’s eruption detached from the volcano around 07:00 AKDT (15:00 UTC) and is drifting east-southeast at an altitude of 45,000 ft above sea level.  Ash emissions continued at a lower altitude of about 20,000–25,000 ft above sea level until about 08:20 AKDT (16:20 UTC). Small explosions are currently being detected in infrasound data and likely represent low-level eruptive activity near the vent area.

Trace to minor amounts of ashfall were reported by the communities of False Pass, King Cove, Cold Bay and Sand Point.  Ashfall occurred during rainfall in all four communities. No ashfall is expected from the current small explosions that are being detected in infrasound. Refer to the National Weather Service SIGMET for the drifting ash cloud (https://www.weather.gov/aawu/sigmets) and the Ashfall Advisory and Special Weather Statement for trace to minor amounts of ashfall on communities on the lower Alaska Peninsula and surrounding waters (https://www.weather.gov/afc/).

Based on previous eruption cycles, pyroclastic flows and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

An ash cloud from Shishaldin Volcano initially reached 45,000 ft (14 km) above sea level starting at 05:42 am AKDT (13:42 UTC). Ash emissions continue but the height is decreasing. Seismic activity dropped sharply along with the start of ash emissions and now is at low levels. The Aviation Color Code remains at RED and the Volcano Alert Level at WARNING. The National Weather Service has issued a SIGMET for this ash cloud, an Ash Advisory has been issued for False Pass, and a Special Weather Statement has been issued for possible trace ash on Cold Bay, King Cove, and Sand Point.

Based on previous eruption cycles, significant ash emissions are likely to continue for several hours. Pyroclastic flows and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

An ash cloud from Shishaldin Volcano initially reached 45,000 ft (14 km) above sea level starting at 05:42 am AKDT (13:42 UTC). Ash emissions continue but the height is decreasing. Seismic activity dropped sharply along with the start of ash emissions and now is at low levels. The Aviation Color Code remains at RED and the Volcano Alert Level at WARNING. The National Weather Service has issued a SIGMET for this ash cloud, an Ash Advisory has been issued for False Pass, and a Special Weather Statement has been issued for possible trace ash on Cold Bay, King Cove, and Sand Point.

Based on previous eruption cycles, significant ash emissions are likely to continue for several hours. Pyroclastic flows and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

The level of activity at Shishaldin remains high, with increasing seismicity and evidence for lava eruption and volcanic flows. 

Elevated surface temperatures consistent with lava fountaining over the crater rim have been observed during clear conditions overnight. Low-level ash emissions less than 15,000 ft. (4.5 km) above sea level were observed starting at 6 pm AKDT yesterday (02:00 UTC September 25), but these dissipated quickly. Beginning at 12 am AKDT today (08:00 UTC), a series of seismic signals consistent with volcanic flows were recorded on the north side of the volcano. Meteorologic clouds up to 20,000 ft. (6 km) above sea level have obscured view of the volcano since this time, and no ash emissions above this level have been observed.

The current period of heightened seismicity at Shishaldin, which started yesterday morning, has lasted longer than previous events during the 2023 eruption. It remains possible that higher ash emissions will occur along with this increased activity.

Previous recent significant ash events resulted in ash clouds with heights up to 40,000 ft (12 km) above sea level.  These events can occur with little warning. It is also possible that ash emissions may occur at a lower level and be sustained for many hours. AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notices about significant changes in activity as they occur.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

The level of activity has increased at Shishaldin Volcano. After a prolonged low-level eruption over the past day, a strong increase in seismic tremor over the past hour and continued high temperatures at the volcano observed in satellite data over the past 18 hours suggests that stronger explosive activity is likely imminent. Elevated surface temperatures consistent with lava erupting at the summit are evident in the latest satellite data, but no significant ash emissions have been observed. Based on previous eruption cycles, ash emissions are likely to occur and may increase in the next several hours. 

Recent significant ash events during the current eruption resulted in ash clouds with heights up to 40,000 ft (12 km) above sea level.  These events can occur with little warning. It is also possible that ash emissions may occur at a lower-level, steady state and be sustained for many hours. AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notice’s to provide notice of significant changes in activity as they occur.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

Geophysical and remote sensing data indicate that low-level eruption at Shishaldin Volcano continues but remains confined to the summit crater. Strongly elevated surface temperatures and some small-amplitude infrasound detections are occuring. Seismic tremor remains high but has started to slowly decline over the past eight hours. No ash emissions or deposits outside the crater have been observed in satellite or web camera imagery. Based on previous eruptive episodes, it remains possible that this activity may culminate in more significant lava fountaining and ash emissions. AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notice’s to provide notice of significant changes in activity as they occur.

Recent significant ash events during the current eruption resulted in ash clouds with heights up to 40,000 ft (12 km) above sea level. These events can occur with little warning. It is also possible that ash emissions may occur at a lower-level, steady state and be sustained for many hours. 

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

Seismic tremor remains high at Shishaldin Volcano and nearly continuous small infrasound signals are being detected suggesting that low-level eruptive activity is likely occurring with the summit crater. Based on previous eruptive episodes, this activity may culminate in more significant lava fountaining and ash emissions within hours. However, no strongly elevated temperatures indicative of lava at the surface or ash emissions have accompanied the elevated geophysical data thus far. The volcano is mostly obscured by clouds between 10,000 and 15,000 ft above sea level, which preclude observations of possible low-level activity. AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notice’s to provide notice of significant changes in activity as they occur.

Recent significant ash events during the current eruption resulted in ash clouds with heights up to 40,000 ft (12 km) above sea level. These events can occur with little warning. It is also possible that ash emissions may occur at a lower-level, steady state and be sustained for many hours. 

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

Seismic tremor has continued to increase over the day at Shishaldin Volcano and geophysical signals suggest low-level eruptive activity is likely occurring with the summit crater. Based on previous episodes of activity, this activity may culminate in more significant lava fountaining and ash emissions within hours. However, no strongly elevated temperatures indicative of lava at the surface or ash emissions have accompanied the elevated seismicity thus far. The volcano is mostly obscured by clouds between 2,000 and 15,000 ft above sea level, which preclude observations of possible low-level activity. However, regional infrasound sensors have detected some signals from the direction of Shishaldin that suggest minor eruptive activity within the summit crater may been occurring. If geophysical or remote sensing signals intensify or a significant eruption begins, the Alaska Volcano Observatory will issue further notices of volcanic activity. 

Recent significant ash events during the current eruption resulted in ash clouds with heights up to 40,000 ft (12 km) above sea level. These events can occur with little warning. It is also possible that ash emissions may occur at a lower-level, steady state and be sustained for many hours. AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notice’s to provide notice of significant changes in activity as they occur.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

The level of unrest has increased at Shishaldin Volcano. Seismic tremor has increased significantly over the past 36 hours. No strongly elevated temperatures indicative of lava at the surface or ash emissions have accompanied the elevated seismicity at this time, although the volcano is obscured by clouds. Based on previous episodes of activity, eruptive activity in the form of lava fountaining and ash emissions is possible within hours. If geophysical or remote sensing signals intensify, the Alaska Volcano Observatory will issue further notices of volcanic activity. 

Recent significant ash events during the current eruption resulted in ash clouds with heights up to 40,000 ft (12 km) above sea level. These events can occur with little warning. It is also possible that ash emissions may occur at a lower-level, steady state and be sustained for many hours. AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notice’s to provide notice of significant changes in activity as they occur.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

Analysis of seismoacoustic signals and observations of a submarine plume in satellite imagery are consistent with an eruption at Ruby seamount beginning the morning of September 15 ChST. Satellite imagery shows a submarine plume of discolored water by sunrise at ~20:50 UTC on September 14 (06:50 ChST September 15). This plume does not breach the ocean surface. Onset of the eruption prior to the plume detection is not observed in geophysical data. Retrospective analysis of seismoacoustic data from a geophysical monitoring station on Saipan, 50 km to the southeast of the volcano, capture eruption signals beginning at 14:27 ChST on September 15 (04:27 UTC). The activity was also picked up on other regional geophysical monitoring networks in the Pacific. The plume is detached in satellite imagery by the morning of September 16 and no activity has since been observed on geophysical networks. Due to this activity at Ruby, the Aviation Color Code and Volcano Alert Level are being raised to YELLOW/ADVISORY.

It is possible that further eruptive activity could occur at Ruby. The volcano is monitored by a regional geophysical monitoring network, including a station at Saipan (50 km away) as well as others in Guam, Japan, and an underwater pressure sensor at Wake Island. Analysis of the geophsyical data was done in collaboration with the Laboratoire de Geophysique in Tahiti.

Ruby is a submarine volcano that rises to within 230 m of the sea surface near the southern end of the Mariana arc northwest of the island of Saipan. The volcano was first detected in eruption in 1966 by sonar signals. In 1995, submarine explosions were heard, accompanied by a fish kill, sulfurous odors, bubbling water, and the detection of volcanic tremor.

The eruption that began at Kīlauea summit on September 10 has ended. Lava supply to the vents on the downdropped block in Kīlauea 's summit caldera ceased yesterday, September 16, based upon visual and geophysical observations. Sulfur dioxide (SO2) emissions have decreased to near pre-eruption background levels.   

Accordingly, the USGS Hawaiian Volcano Observatory (HVO) is lowering the Volcano Alert Level for ground-based hazards from WATCH to ADVISORY and the Aviation Color Code from ORANGE to YELLOW.  

During the morning of September 16, HVO field crews reported that active lava was no longer flowing onto Halemaʻumaʻu crater floor and was restricted to a ponded area north of the vents on the downdropped block. They observed lava spattering at the vents cease at approximately 11:15 am yesterday, September 16, and webcam views show the ponded lava stagnant by around noon. Overnight webcam views showed incandescence across the eruption area as lava erupted over the past week continues to cool. These observations are supported by geophysical data which shows that eruptive tremor (a signal associated with fluid movement) in the summit region decreased over September 15 and 16 and returned to pre-eruption levels by 5 p.m. HST on September 16. Over that period, mild inflation has been recorded at summit tiltmeters. Sulfur dioxide (SO2) emissions have also decreased to near background levels, and were measured at a rate of 800 tonnes per day yesterday, September 16.

More eruption information on the September 2023 Kīlauea summit eruption is available at: https://www.usgs.gov/volcanoes/kilauea/recent-eruption. 

There remains the potential for eruptive activity to resume in the near future at or near the summit of Kīlauea with little or no warning.

HVO continues to closely monitor Kīlauea for signs of renewed activity. Should volcanic activity change significantly, a new Volcanic Activity Notice will be issued. 

Hazards are still present on Kīlauea and are described below. Residents and visitors should stay informed and follow County of Hawai‘i and Hawaiʻi Volcanoes National Park guidelines. 

For more information about the meaning of volcano alert levels and aviation color codes, see https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes 

Activity at Shishaldin Volcano has declined. Seismicity decreased rapidly around 6:30 pm AKDT Sept. 15  (4:30 UTC, Sept. 16) yet remained elevated until 9:00 p.m. AKDT.  During this period of waning seismicity, volcanic lightning continued to be detected, indicating continued ash production.  The last detection of volcanic lighting was at 8:48 p.m. AKDT and seismicity has returned to pre-eruptive levels, indicating that significant ash emissions have ended. Thus, the Aviation Color Code and Volcano Alert Level are being decreased to ORANGE/WATCH.

Trace ash fall was reported in the community of False Pass between 18:00 and 20:30 AKDT (0200 to 0430 UTC). The National Weather Service has issued a SIGMET for the drifting ash cloud, and a Special Weather Statement has been issued for trace ash on False Pass.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

The explosive eruption at Shishaldin Volcano continues, but has decreased in intensity. An explosive event began at 5:10 p.m. AKDT on September 15, 2023 (01:10 UTC on Sept 16) after a period of rapidly increasing seismicity. The explosive event produced an ash-rich cloud that the National Weather Service estimated reached an altitude of 42,000 ft  (12.8 km) above sea level and was accompanied by volcanic lightning.

This upper level cloud detached from the vent around 18:30 AKDT (0230 UTC) and is drifting towards the east. Seismicity began to decrease dramaticially at about this same time. Beginning around 19:30 AKDT (0330 UTC), lightning resumed indicating continued ash emssions. The meterological cloud deck over the volcano is currently at about 22,500 ft (6.8 km) above sea level and ash emissions are not visible in satellite data. Explosions continue to be detected in infrasound data, at a lower level than during the most energetic phase of this event. Seismicity is lower, it has not reached its pre-event levels and the Aviation Color Code and Volcano Alert Level remain at RED/WARNING.

Trace ash fall was reported in the community of False Pass between 18:00 and 20:30 AKDT (0200 to 0430 UTC). The National Weather Service has issued a SIGMET for the drifting ash cloud, and a Special Weather Statement has been issued for trace ash on False Pass.

Based on previous eruption cycles, significant ash emissions are likely to continue for several hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

An explosive eruption from Shishaldin began around 5:10 p.m. AKDT on September 15, 2023 (01:10 UTC on Sept 16) following a several-hour increase in seismicity.  Ash is currently being produced and is drifting to the east below the cloud deck of 27,000 ft above sea level. The Aviation Color Code and Volcano Alert Level is being raised to RED/WARNING.

Recent significant ash events during the current eruption resulted in ash clouds with heights up to 40,000 ft (12 km) above sea level.  These events can occur with little warning. It is also possible that ash emissions may occur at a lower-level, steady state and be sustained for many hours. AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notice’s to provide notice of significant changes in activity as they occur.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

The level of unrest is increasing at Shishaldin Volcano. Seismic tremor has intensified over the past 6 hours and, during Shishaldin's ongoing eruptive period, this has often been followed by ash-producing explosive activity over the next several hours. 

Recent significant ash events during the current eruption resulted in ash clouds with heights up to 40,000 ft (12 km) above sea level.  These events can occur with little warning. It is also possible that ash emissions may occur at a lower-level, steady state and be sustained for many hours. AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notice’s to provide notice of significant changes in activity as they occur.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

Following the eruptive activity at Shishaldin Volcano overnight, the level of unrest has reduced significantly. Seismicity declined starting about 7:30 AKDT (15:30 UTC) and remains at low levels. No ash emissions were observed during the period of elevated seismicity overnight, but high clouds were present and could have obscured low-level ash emissions.  

AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notice’s to provide notice of significant changes in activity as they occur.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

The level of unrest has slowly increased at Shishaldin Volcano. A steady increase in seismic tremor over the past 7 hours suggests that explosive activity is likely.  Cloud cover is currently obscuring satellite views of the volcano. Web camera views show incandescent lava at the summit. Based on previous eruption cycles, ash emissions are likely to occur over the next several hours. 

Recent significant ash events during the current eruption resulted in ash clouds with heights up to 40,000 ft (12 km) above sea level.  These events can occur with little warning. It is also possible that ash emissions may occur at a lower-level, steady state and be sustained for many hours. AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notice’s to provide notice of significant changes in activity as they occur.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

The eruption within Kīlauea's summit caldera that began yesterday afternoon continues, with eruptive activity confined to the downdropped block and Halemaʻumaʻu crater. HVO is lowering Kīlauea’s volcano alert level from WARNING to WATCH because the style of eruption and fissure location have stabilized, the initial extremely high effusion rates have declined, and no infrastructure is threatened.  Associated hazards are confined to the closed area established by Hawaiʻi Volcanoes National Park.

HVO is lowering Kīlauea’s aviation color code from RED to ORANGE because there is currently no threat of significant volcanic ash emission into the atmosphere outside of the hazardous closed area within Hawai‘i Volcanoes National Park. The eruption plume, composed largely of sulfur dioxide and minor volcanic particles, continues to rise to the base of the inversion level at about 8,000-10,000 feet (2,400-3,000 meters) above sea level.  The plume concentration has decreased some due to the drop in effusion rate, but still remains high.  Hazards associated with the eruption are limited and are described below. 

Kīlauea’s summit eruption is expected to continue and remain confined to Kīlauea caldera within Hawai‘i Volcanoes National Park.  HVO does not see any indication of activity migrating elsewhere on Kīlauea volcano and expects the eruption to remain confined to the summit region. 

HVO will continue to monitor this activity closely and report any significant changes in future notices.

HVO is in constant communication with Hawai‘i Volcanoes National Park as this situation evolves. The activity is confined entirely within the park.

For more information about the meaning of volcano alert levels and aviation color codes, see https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes 

Kīlauea volcano is erupting. At approximately 3:15 a.m./p.m. HST on September 10, 2023, the USGS Hawaiian Volcano Observatory observed eruptive activity in Kīlauea summit webcam images and from field reports indicating that an eruption has commenced within Halemaʻumaʻu crater and on the down dropped block to the east in Kīlauea’s summit caldera, within Hawai‘i Volcanoes National Park.  The eruption was preceded by a period of strong seismicity and rapid uplift of the summit

The USGS Hawaiian Volcano Observatory is elevating Kīlauea’s volcano alert level from WATCH to WARNING and its aviation color code from ORANGE to RED as this eruption and associated hazards are evaluated.  

The opening phases of eruptions are dynamic. Webcam imagery shows fissures at the base of Halemaʻumaʻu crater generating lava flows on the surface of the crater floor. The activity is confined to Halemaʻumaʻu and the hazards will be reassessed as the eruption progresses.

HVO will continue to monitor this activity closely and report any significant changes in future notices.

HVO is in constant communication with Hawai‘i Volcanoes National Park as this situation evolves. The activity is confined entirely within the park.

For more information about the meaning of volcano alert levels and aviation color codes, see https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes 

Kīlauea volcano is not erupting. Increased earthquake activity and changes in the patterns of ground deformation at Kīlauea’s summit began occurring the afternoon of September 10, 2023, indicating movement of magma in the subsurface.

The USGS Hawaiian Volcano Observatory is raising the volcano alert level/aviation color code for Kīlauea from ADVISORY/YELLOW to WATCH/ORANGE due to this activity.

At this time, it is not possible to say with certainty if this activity will lead to an eruption; the activity may remain below ground. However, an eruption in Kīlauea’s summit region, within Hawai‘i Volcanoes National Park and away from infrastructure, is one potential outcome. Based on patterns of earthquake activity and ground deformation, it is likely that any new eruptive activity will occur in or near Halemaʻumaʻu crater, within the closed area of Hawaiʻi Volcanoes National Park. 

HVO will continue to monitor this activity closely and adjust the alert level accordingly.

HVO is in constant communication with Hawai‘i Volcanoes National Park as this situation evolves. The activity is confined entirely within the park.

Activity at Shishaldin Volcano has declined. Web camera observations through 1:30 pm AKDT (21:30 UTC) show that significant ash emissions have ended. Seismicity decreased rapidly around 12:30 pm AKDT (20:30 UTC) and remains low. Thus, the Aviation Color Code and Volcano Alert Level are being decreased to ORANGE/WATCH.

The National Weather Service has issued a SIGMET for the ash cloud (https://www.weather.gov/aawu/sigmets), and a Special Weather Statement and a Marine Weather Statement has been issued for possible trace ash fall on Unimak Island and on nearby marine waters, respectively.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

Correction to previous VAN/VONA issued at 12:31 PM AKDT. Alert Level remains at WARNING. 

An explosive eruption from Shishaldin began at ~08:30 AKDT (1630 UTC) following a several-hour increase in seismicity and produced an extensive ash cloud that moved towards the south-southeast at an estimated altitude of 32,000 ft (9.7 km) above sea level. Around 19:00 AKDT (1900 UTC) seismic amplitude decreased rapidly, and the altitude of the ash emissions as observed by satellite also decreased to an estimated altitude of ~15,000 ft (4.5 km). At 12:00 pm AKDT (2000 UTC), the lower-altitude ash cloud extended for ~75 miles (125 km) towards the east. The Aviation Color Code and Volcano Alert Level remains at RED/WARNING.

The National Weather Service has issued a SIGMET for the ash cloud (https://www.weather.gov/aawu/sigmets), and a Special Weather Statement and a Marine Weather Statement has been issued for possible trace ash fall on Unimak Island and on nearby marine waters, respectively. 

Based on previous eruption cycles, significant ash emissions are likely to continue for several hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

An explosive eruption from Shishaldin began at ~08:30 AKDT (1630 UTC) following a several-hour increase in seismicity and produced an extensive ash cloud that moved towards the south-southeast at an estimated altitude of 32,000 ft (9.7 km) above sea level. Around 19:00 AKDT (1900 UTC) seismic amplitude decreased rapidly, and the altitude of the ash emissions as observed by satellite also decreased to an estimated altitude of ~15,000 ft (4.5 km). At 12:00 pm AKDT (2000 UTC), the lower-altitude ash cloud extended for ~75 miles (125 km) towards the east. The Aviation Color Code and Volcano Alert Level remains at RED/WARNING.

The National Weather Service has issued a SIGMET for the ash cloud (https://www.weather.gov/aawu/sigmets), and a Special Weather Statement and a Marine Weather Statement has been issued for possible trace ash fall on Unimak Island and on nearby marine waters, respectively. 

Based on previous eruption cycles, significant ash emissions are likely to continue for several hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

An ash cloud from Shishaldin Volcano reaching 25,000 ft (7.3 km) above sea level and rising was reported by a pilot at at 8:42 am AKDT (1642 UTC). Satellite data suggests that the cloud may be as high as 30,000 ft above sea level (9.1 km). This follows a several-hour increase in seismicity. In response, the Aviation Color Code is being raised to RED and the Volcano Alert Level is being raised to WARNING. The cloud is visible in satellite data moving towards the southeast and lightning associated with the ash cloud has been detected. 

Based on previous eruption cycles, significant ash emissions are likely to continue for several hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

Satellite observations through 1200 am AKDT (0800 UTC) show that ash emissions have ended. Seismicity decreased rapidly around 5:30 pm AKDT (0130 UTC on 26 August) and remains low. Thus, the Avation Color Code and Volcano Alert Level are being decreased to ORANGE/WATCH. 

The National Weather Service is responsible for tracking the drifting ash cloud and SIGMETs have been issued today and will continue until the cloud disperses. See https://www.weather.gov/aawu/SIGMETs for current information for aviation.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

Explosive eruptive activity is continuing at Shishaldin Volcano. An ash cloud continues to be observed in satellite data at an altitude of 21,000 ft (6.4 km) above sea level moving towards the northeast. This is a decrease in altitude from earlier today. Seismic tremor decreased rapidly around 5:30 pm AKDT (0130 UTC) and is approaching levels observed prior to the onset of ash emissions.

Based on previous eruption cycles, it is likley that ash emissions are starting to decrease and may end over the next few hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano. Minor to trace amounts of ash fall are likely to the north of the volcano and in the water immediately offshore. No ash fall is expected in populated areas.

The National Weather Service is responsible for tracking the drifting ash cloud and SIGMETs have been issued throughout the day. See https://www.weather.gov/aawu/SIGMETs for current information for aviation.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

Explosive eruptive activity is continuing at Shishaldin Volcano. An ash cloud rising to about 30,000 ft (9 km) above sea level and extending roughly 280 miles (450 km) northeast of the volcano is evident in satellite data. A SIGMET for this ash cloud has been issued. Seismic tremor increased this afternoon and peaked around 4:30 pm Alaska time (00:30 UTC). The tremor has since dropped but remains elevated.

Based on previous eruption cycles, significant ash emissions are likely to continue for the next few hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

An ash cloud from Shishaldin Volcano reaching 28,000 ft (8.5 km) has been reported by aircraft in the vicinity of the volcano. This follows a several-hour increase in seismic activity. In response, the Aviation Color Code is being raised to RED and the Volcano Alert Level is being raised to WARNING.

Based on previous eruption cycles, significant ash emissions are likely to continue for several hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

The level of unrest has increased at Shishaldin Volcano. Seismic tremor began to increase at around 03:00 this morning Alaska time (11:00 UTC) and is escalating. Elevated surface temperatures consistent with lava erupting at the summit are evident in the latest satellite data. Local infrasound data suggests low-level explosions are occurring. Based on previous eruption cycles over the past month, ash emissions are likely over the next few hours. 

There have been seven significant explosive events during the current eruption. These have resulted in ash clouds with heights up to 40,000 ft (12 km) above sea level and pyroclastic deposits near the volcano.  These events can occur with little warning. It is also possible that ash emissions may occur at a lower-level, steady state and be sustained for many hours. AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notice’s to provide updates of significant changes in activity as they occur.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

A decrease in seismic activity at Mount Cleveland over the past few weeks to background levels has prompted the Alaska Volcano Observatory to downgrade the Aviation Color Code and Volcano Alert Level from YELLOW/ADVISORY to GREEN/NORMAL.

An increase in the number of small earthquakes near Mount Cleveland in mid-July 2023 prompted raising the Aviation Color Code and Volcano Alert Level from UNASSIGNED/UNASSIGNED to YELLOW/ADVISORY on July 19. This activity  continued for the next several weeks but has since declined. Slightly elevated surface temperatures and weak gas emissions from the summit crater continue to be observed occasionally, but this is not unusual for Mount Cleveland.

The last eruptive activity at Mount Cleveland was a short-lived explosion during the evening (local time) of June 1, 2020. Despite the current pause, the eruptive period at Mount Cleveland, dating back to 2001, remains ongoing and future explosions are likely. These have occurred without warning and typically generate small clouds of volcanic ash that are a hazard in the immediate vicinity of the volcano, though more significant ash emissions are possible.

Mount Cleveland is currently monitored with a five-station real-time seismic network. We now have enough stations at the volcano to locate volcanic earthquakes thanks to a partnership between AVO and the AVERT (Anticipating Volcanic Eruptions in Real-Time) project at Columbia University. Based on past events, explosive eruptions of Cleveland may occur with little or no warning. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.

The number of earthquakes beneath Aniakchak volcano and the measurable uplift of the ground surface in the caldera have declined to background levels. Due to these changes, the Alaska Volcano Observatory is lowering the Aviation Color Code to GREEN and the Volcano Alert Level to NORMAL. There have been no signs of unrest in other monitoring data. 

AVO monitors Aniakchak with a local network, which consists of six seismometers, a web camera, and a single infrasound sensor, as well as satellite remote sensing data and regional infrasound and lightning networks. To view current monitoring data, see https://avo.alaska.edu/activity/Aniakchak.php 

The level of eruptive activity at Shishaldin Volcano has gradually declined since yesterday afternoon. Seismicity has decreased, and significant explosions or ash emissions are no longer detected. Clear web camera views this morning show only minor steaming at the summit. Recent satellite views indicated a persistent thermal anomaly at the summit, indicating the presence of hot eruptive material.

Based on previous eruption cycles, significant ash emissions may occur again and will likely be preceded by gradually increasing seismicity. Pyroclastic and mudflows will probably happen on the immediate flanks of the volcano should another vigorous episode of eruptive activity occur.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

Explosive eruptive activity is continuing at Shishaldin Volcano. A low-level ash cloud to about 16,000 ft (5 km) above sea level and moving northeast is evident in satellite data and was observed by passing pilots. The National Weather Service has issued a SIGMET for this ash cloud.

Based on previous eruption cycles, significant ash emissions may continue for several hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lightning data, and satellite images to detect eruptions.

Explosive eruptive activity is occurring at Shishaldin Volcano. A low-level ash cloud to about 25,000 ft (7.6 km) above sea level and moving northeast is evident in satellite data. This follows a several-hour increase in seismic tremor. Explosion signals have been detected in infrasound data since at least 2:00 AKDT (10:00 UTC) and the National Weather Service has detected lightning in the vicinity of the volcano. A SIGMET for this ash cloud has been issued.

Based on previous eruption cycles, significant ash emissions are likely to continue for the next few hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

The level of unrest has increased at Shishaldin Volcano. A steady increase in seismic tremor has been observed over the past 5 hours. Elevated surface temperatures consistent with lava erupting at the summit are evident in the latest satellite data. Based on previous eruption cycles over the past month, ash emissions are likely to occur and may increase over the next few hours. 

Recent significant ash events during the current eruption resulted in ash clouds with heights up to 40,000 ft (12 km) above sea level.  These events can occur with little warning. It is also possible that ash emissions may occur at a lower-level, steady state and be sustained for many hours. AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notice’s to provide notice of significant changes in activity as they occur.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

Volcanic activity has significantly declined at Shishaldin Volcano and any remaining ash emissions are likely low level. Seismic tremor began declining from a peak at 2:00 pm AKDT (22:00 UTC) and is and is currently at low levels. The eruption produced a sustained ash plume ash plume during the period of high seismicity which drifted to the northeast.  Currently, meteorological clouds at 30,000 ft (9 km) above sea level have obscured the volcano and any potential ash clouds.  It is possible that low level ash production could be continuing during this period of waning seismicity.  Due to this decrease in intensity of the eruption, the Aviation Color Code is being lowered to ORANGE and the Alert Level is being lowered to WATCH.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

Eruptive activity continues at Shishaldin Volcano, with continuous ash emissions, strongly elevated surface temperatures, and high levels of seismic tremor. A continuous ash plume extends to the east-northeast with two branches visible in satellite imagery and confirmed by passing aircraft. The volcanic cloud extends up to ~112 miles (~180 km) from the volcano, with its top as high as 31,000 ft (9.4 km) above sea level. Additionally, a gas-rich but less ash-laden volcanic plume is also drifting to the southeast. The National Weather Service has issued a SIGMET for these ash clouds, a Marine Weather Statement and a Special Weather Statement for trace ash on marine waters and land areas downwind of Shishaldin Volcano. The color code and alert level remain at RED/WARNING. 

Based on previous eruption cycles, significant ash emissions are likely to continue for several hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

An ash cloud from Shishaldin Volcano reaching 30,000 ft (9 km) above sea level was observed in satellite data at 9:00 am AKDT (17:00 UTC). This follows a several-hour increase in observed eruptive activity. In response, the Aviation Color Code is being raised to RED and the Volcano Alert Level is being raised to WARNING. The National Weather Service has issued a SIGMET for this ash cloud, and a Special Weather Statement has been issued for possible trace ash on marine waters downwind of Shishaldin Volcano.

Based on previous eruption cycles, significant ash emissions are likely to continue for several hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

Explosive eruptive activity is occurring at Shishaldin Volcano. A low-level ash cloud up to 25,000 ft (7.6 km) above sea level and extending 37-47 miles (60-75 km) northeast of the volcano is evident in satellite data at 5:20 AM AKDT (13:20 UTC) and reported by passing pilots at 8:36 AM AKDT (16:36 UTC). This follows a 20-hour increase in seismic tremor and an increase in surface temperatures at the volcano seen in satellite data. Explosion signals have been detected in infrasound and seismic data overnight during cloudy altmospheric conditions. Surface temperatures have greatly increased in the past few hours. The National Weather Service has issued a SIGMET for this ash cloud.

Based on previous eruption cycles, significant ash emissions are likely to continue for the next few hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

The level of unrest has increased at Shishaldin Volcano. A steady increase in seismic tremor has been observed over the past 7 hours. Despite cloud cover obscuring the volcano, elevated surface temperatures consistent with lava erupting at the summit are evident in the latest satellite data. Based on previous eruption cycles, ash emissions are likely to occur and may increase over the next few hours. 

Recent significant ash events during the current eruption resulted in ash clouds with heights up to 40,000 ft (12 km) above sea level.  These events can occur with little warning. It is also possible that ash emissions may occur at a lower-level, steady state and be sustained for many hours. AVO is monitoring the volcano closely and will issue additional Volcanic Activity Notice’s to provide notice of significant changes in activity as they occur.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network.  In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

No eruptive activity has been observed at Semisopochnoi volcano since May 5, 2023, and there are no signs of heighted volcanic unrest. Reflecting these conditions, the Aviation Color Code is being lowered to GREEN and Volcano Alert Level to NORMAL. 

The last evidence of ash emissions from the volcano was observed on May 5 and consisted of a light dusting of ash on the northwest flank of Mount Young. The last detection of possible explosions in monitoring data was April 25, 2023. Since this time, earthquake activity has been at low levels. Steam plumes continue from the north crater of Mount Young. Although steaming was not observed from this vent prior the start of this eruption, it is common for steam plumes to persist at volcanoes for years following an eruption as the volcano slowly cools. 

The current eruption sequence at Semisopochnoi began in September 2018 and has consisted of small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Young and ash clouds usually under 10,000 ft (3 km) above sea level with occasional periods of continuous ash production. While current observations indicate that this eruption may be over, it is also possible activity could resume, and small ash-producing events could occur with little warning. The Alaska Volcano Observatory will continue to closely monitor Semisopochnoi and report on any changes in activity. 

Semisopochnoi is monitored by a local seismic and infrasound network, local web cameras, regional lightning and infrasound sensors, and satellite data.  

The eruption of Shishaldin Volcano has gradually declined after increasing overnight. Seismicity has decreased and significant explosions are no longer being detected in infrasound data. Meteorological clouds up to 20,000–25,000 ft (6.1–7.6 km) above sea level began obscuring views of the volcano starting around 11:30 am AKDT (17:30 UTC). It is likely that lingering low-level ash emissions are continuing in the vicinity of the volcano.

Seismic activity and satellite data indicated that eruptive activity began increasing around 10:00 pm AKDT on July 25 (July 26 06:00 UTC). A sustained 15,000 ft (6 km) ash cloud was detected around 5:00 am AKDT (13:00 UTC) and drifted ENE from the volcano. Ash emissions, while diffuse, were visible in satellite data extending about 78 mi (125 km) from the volcano until clouds obscured views starting around 11:30 AKDT (17:30 UTC). The National Weather Service issued a SIGMET for this cloud.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network has been partially impaired over the last few weeks due to telecommunications issues but seismic stations and web cameras south of the volcano were brought back online on July 19. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

Explosive eruptive activity is occurring at Shishaldin Volcano. A low-level ash cloud to about 15,000 ft (6 km) above sea level and moving ENE is evident in satellite data. This follows a several-hour increase in seismic tremor and an increase in temperatures at the volcano seen in satellite data. Explosion signals have been detected in infrasound data since at least 02:00 AKDT (10 UTC). The National Weather Service has issued a SIGMET for this ash cloud, and a Marine Weather Statement has been issued for possible trace ash on marine waters NE of the volcano.

Based on previous eruption cycles, significant ash emissions are likely to continue for the next few hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

The last four significant ash events during the current eruption resulted in ash clouds with heights up to 40,000 ft. (12 km) above sea level, similar to other historical eruptions. These events can occur with little warning. 

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network has been partially impaired over the last few weeks due to telecommunications issues but seismic stations and web cameras south of the volcano were brought back online on July 19. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

The level of unrest has increased at Shishaldin Volcano. A steady increase in seismic tremor over the past 4 hours and an increase in temperatures at the volcano observed in satellite data over the past 2 hours suggests that explosive activity is imminent.  Despite cloud cover obscuring the volcano, elevated surface temperatures consistent with lava erupting at the summit are evident in the latest satellite data. Based on previous eruption cycles, minor ash emissions are likely to occur and may increase over the next few hours. 

The last four significant ash events during the current eruption resulted in ash clouds with heights up to 40,000 ft. (12 km) above sea level, similar to other historical eruptions. These events can occur with little warning. 

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network has been partially impaired over the last few weeks due to telecommunications issues but seismic stations and web cameras south of the volcano were brought back online on July 19. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

Volcanic activity has significantly declined at Shishaldin Volcano. Seismic tremor began declining from a peak at 12:30 am AKDT (08:30 UTC) and is and is currently at low levels. Significant ash eruption notably decreased in satellite data around 1:30 am (09:30 UTC). Satellite data continue to indicate elevated surface temperatures at the summit associated with lava erupting at the surface and possible low-level ash emissions below regional cloud tops which are currently at around 20,000 ft. (6 km) above sea level.

A sustained ash plume with a height of 37,000 ft. (11 km) above sea level erupted between 11:20 pm AKDT on July 22 (07:20 UTC on July 23) and 12:30 am on July 23 (08:30 UTC on July 23). Around this time plume height decreased to around 15,000 ft. (4.5 km) above sea level.

A detached plume is currently drifting to the northeast along the Alaska Peninsula. The National Weather Service has issued a SIGMET for this ash cloud, as well as a Marine Weather Statement and an Ashfall Advisory that were issued for areas that might expect ashfall associated with this eruption.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network has been partially impaired over the last few weeks due to telecommunications issues but seismic stations and web cameras south of the volcano were brought back online on July 19. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

An ash cloud from Shishaldin Volcano reaching 30,000 ft. (9 km) was observed in satellite data and pilot reports at 11:30 pm AKDT (07:30 UTC on July 23). This follows a several-hour increase in observed eruptive activity. In response, the aviation Color Code is being raised to RED and the Volcano Alert Level is being raised to WARNING. The National Weather Service has issued a SIGMET for this ash cloud, and a Special Weather Statement has been issued for possible trace ash on False Pass.

Based on previous eruption cycles, significant ash emissions are likely to continue for an hour or more. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network has been partially impaired over the last few weeks due to telecommunications issues but seismic stations and web cameras south of the volcano were brought back online on July 19. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

The level of unrest has increased at Shishaldin Volcano over the past 6 hours. A steady increase in seismic tremor and intermittent infrasound signals consistent with small explosions are ongoing. Despite cloud cover obscuring the volcano, elevated surface temperatures consistent with lava erupting at the summit are evident in the latest satellite data. Based on previous eruption cycles, minor ash emissions are likely to occur and may increase over the next few hours. Clouds are obscuring web cameras and satellite images, and we have had no clear views of the volcano over the past day. Based on the level of unrest, we infer that any ash emissions occurring are below 20,000 ft. (6 km) above sea level and below the altitude of clouds in the region.

The last three significant ash events during the current eruption resulted in ash clouds up to 40,000 ft. (12 km) above sea level, similar to other historical eruptions. These events can occur with little warning. 

Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network has been partially impaired over the last few weeks due to telecommunications issues but seismic stations and web cameras south of the volcano were brought back online on July 19. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.

There has been an increase in the number of earthquakes observed near Cleveland volcano over the past week. Numerous earthquakes have been detected and 37 of these were large enough to be located by the local seismic network. Most of the earthquakes from early in the week located in the mid to shallow portions of the Earth’s crust, less than 11 miles (18 km) below the surface, while more recent earthquakes have been located at shallower depths, less than 4 miles (6 km) below the surface. These earthquakes are small (less than magnitude 2), but the frequency of events is unusual for Cleveland. These data along with satellite observations of elevated surface temperatures at the summit crater and continued gas emissions suggest an increased likelihood of a future eruption. In response, the Alaska Volcano Observatory is increasing the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.

The last eruptive activity at Cleveland volcano was a short-lived explosion during the evening (local time) of June 1, 2020. Despite the current pause, the eruptive period at Cleveland, dating back to 2001, remains ongoing and future explosions are likely. These have occurred without warning and typically generate small clouds of volcanic ash that are a hazard in the immediate vicinity of the volcano, though more significant ash emissions are possible.

Cleveland volcano is currently monitored with a five-station real-time seismic network. Based on past events, explosive eruptions of Cleveland may occur with little or no warning. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.

Earthquake activity near Takawangha Volcano has decreased in both rate and magnitude from the peak of the swarm on March 9–11 when over 150 earthquakes per day were located on Tanaga Island to less than 3 earthquakes per day in the last few weeks. Recent satellite images do not indicate any ongoing deformation on the island. No other signs of volcanic unrest have been detected. The Alaska Volcano Observatory is therefore lowering the Aviation Color Code to GREEN and the Volcano Alert Level to NORMAL.

The Alaska Volcano Observatory will continue to closely monitor seismic activity on Tanaga Island.

Takawangha is monitored with a local seismic network, a single local infrasound sensor, regional infrasound and lightning sensors, and satellite imagery.  

For current monitoring data: https://avo.alaska.edu/activity/Takawangha.php

Earthquake activity near Tanaga Volcano has decreased in both rate and magnitude from the peak of the swarm on March 9–11 when over 150 earthquakes per day were located on Tanaga Island to less than 3 earthquakes per day in the last few weeks. Recent satellite images do not indicate any ongoing deformation on the island. No other signs of volcanic unrest have been detected. The Alaska Volcano Observatory is therefore lowering the Aviation Color Code to GREEN and the Volcano Alert Level to NORMAL.

The Alaska Volcano Observatory will continue to closely monitor seismic activity on Tanaga Island.

Tanaga is monitored with a local seismic network, a single local infrasound sensor, regional infrasound and lightning sensors, and satellite imagery.  

For current monitoring data: https://avo.alaska.edu/activity/Tanaga.php

The eruption of Shishaldin Volcano has gradually declined. Current observations indicate continued but low-level ash emissions below 10,000 ft. (3 km) above sea level and drifting to the south. Reflecting this lower-level activity, the Aviation Color Code is being reduced to ORANGE and the Volcano Alert Level is being lowered to WATCH. 

This morning a significant ash plume was detected starting around 7:00 am AKDT (15:00 UTC) and reaching a height of around 30,000 ft. (7 km) above sea level. Around 9:30 am AKDT (17:30 UTC) satellite data showed the main initial plume had detached but residual, low-level ash emissions continued from the vent. The detached plume is still visible between 60–280 mi (100 and 450 km) away from the volcano. The National Weather Service has issued a SIGMET for this cloud.

Explosive eruptive activity can resume quickly and with little warning. Eruptions from Shishaldin have produced minor and on occasion significant ash clouds in the past. Shishaldin is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network is partially impaired, therefore AVO is also using nearby geophysical networks, satellite data and regional infrasound and lighting data to detect activity. AVO will continue to closely monitor unrest at Shishaldin Volcano.

An ash cloud with an initial height of around 30,000 ft. (7 km) above sea level from Shishaldin volcano began at 7:00 am AKDT (15:00 UTC) and is drifting SSE. The eruption is continuing and recent pilot observations estimated a 24,000 ft. (6 km) above sea level height. The aviation Color Code remains at RED and the Volcano Alert Level at WARNING. The National Weather Service has issued a SIGMET for this activity.

Eruptive activity began increasing overnight starting around 1 am AKDT (09:00 UTC) with increased lava eruption from or within the summit crater but no significant ash emissions. Activity was detected on regional infrasound arrays, increasing seismic tremor, and elevated surface temperatures in satellite data. Overnight webcam images confirmed glowing from the summit with only minor ash emission.

Eruptions from Shishaldin have produced minor and on occasion significant ash clouds in the past.  These can occur with little warning. Shishaldin is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network is partially impaired, therefore AVO is also using nearby geophysical networks, satellite data and regional infrasound and lighting data to detect activity. AVO will continue to closely monitor unrest at Shishaldin Volcano. 

The eruption of Shishaldin Volcano has intensified. A rapidly growing ash cloud was observed starting at 7:00 am AKDT (15:00 UTC) and drifting SSE. Cloud height is undertermined at this time and could be more than 20,000 ft. above sea level (6 km). In response, the aviation Color Code is being raised to RED and the Volcano Alert Level is being raised to WARNING. The National Weather Service has issued a SIGMET for this activity.

Eruptive activity began increasing overnight starting around 1 am AKDT (09:00 UTC) with increased lava eruption from or within the summit crater but no significant ash emissions. Activity was detected on regional infrasound arrays, increasing seismic tremor, and elevated surface temperatures in satellite data. Overnight webcam images confirmed glowing from the summit with only minor ash emission.

Eruptions from Shishaldin have produced minor and on occasion significant ash clouds in the past.  These can occur with little warning. Shishaldin is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network is partially impaired, therefore AVO is also using nearby geophysical networks, satellite data and regional infrasound and lighting data to detect activity. AVO will continue to closely monitor unrest at Shishaldin Volcano. 

Consistent signs of unrest at Ahyi Seamount have not occurred for over four weeks. Underwater pressure sensors near Wake Island have not detected clear signs of underwater volcanic activity since early June and the last satellite observations of discolored water near the seamount was seen on May 22, 2023. 

Starting mid-October 2022, hydroacoustic sensors at Wake Island, 1,410 miles (2,270 km) east of Ahyi, began recording signals consistent with activity from an undersea volcanic source. In collaboration with the Laboratoire de Geophysique in Tahiti, a combined analysis of the hydroacoustic signals and data from seismic stations located at Guam and Chichijima Island, Japan, confirmed that the source of this activity was at or near Ahyi seamount.  Observations of discolored water above the seamount in satellite data confirmed activity at Ahyi. The activity appears to have paused beginning in early April but briefly resumed in late May.  

Due to the apparent absence of activity over the last month, the aviation color code is being lowered from YELLOW to UNASSIGNED and the alert level is being lowered from ADVISORY to UNASSIGNED. 

Explosive eruptive activity at Shishaldin Volcano has declined. Seismicity has significantly declined and no explosion signals are being detected in infrasound (pressure sensor) data. The drifting ash cloud from last night's activity is still visible in satellite imagery about 350 nautical miles ESE from the volcano. The NWS has a SIGMET for this cloud and estimate it to be under 16,000 ft (4.9 km) above sea level. In response to this decline in explosive activity, the Aviation Color Code is being reduced to ORANGE and the Volcano Alert Level is being raised to WATCH. 

Explosive eruptive activity can resume quickly and with little warning. Eruptions from Shishaldin have produced minor and on occasion significant ash clouds in the past. Shishaldin is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network is partially impaired, therefore AVO is also using nearby geophysical networks, satellite data and regional infrasound and lighting data to detect activity. AVO will continue to closely monitor unrest at Shishaldin Volcano. 

The explosive eruption of Shishaldin Volcano is continuing. A continuous ash plume now extends over 80 mi (125 km) to the SSE from the volcano with an altitude of about 16,000 ft (4.9 km) above sea level. Seismicity has remained elevated for over 6 hours and frequent explosion signals are being detected at regional infrasound (pressure sensor) networks. Some explosions are sending ash plumes as high as 20,000 ft (6 km) above sea level. Due to the duration of this current activity and the extent of the distributing ash cloud the Aviation Color Code is being raised to RED and the Volcano Alert Level is being raised to WARNING. 

The recent magnitude 7.3 earthquake located 55 mi (89 km) SW of Sand Point is not related to volcanic activity.

Eruptions from Shishaldin have produced minor and on occasion significant ash clouds in the past. These can occur with little warning. Shishaldin is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network is partially impaired, therefore AVO is also using nearby geophysical networks, satellite data and regional infrasound and lighting data to detect activity. AVO will continue to closely monitor unrest at Shishaldin Volcano. 

The eruption of Shishaldin Volcano has intensified. An ash cloud to 15,000 ft  (4.6 km) above sea level and drifting to the SSE has been observed in satellite data starting at about 9:00 pm AKDT (17:00 UTC). The National Weather Service has issued a SIGMET for this activty.  Seismic tremor amplitudes began to increase starting around 5:00 pm AKDT (1:00 UTC) and are continuing.  The actvity has also been observed on regional infrasound (presure sensor) arrays. 

Eruptions from Shishaldin have produced minor and on occasion significant ash clouds in the past.  These can occur with little warning. Shishaldin is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network is partially impaired, therefore AVO is also using nearby geophysical networks, satellite data and regional infrasound and lighting data to detect activity. AVO will continue to closely monitor unrest at Shishaldin Volcano. 

A significant explosion occurred at 1:09 am AKDT (9:09 UTC) this morning and produced an ash cloud that initially reached 30,000 to 40,000 ft (9–12 km) above sea level and drifted south over the Pacific Ocean. A second smaller explosion occurred at 7:10 am AKDT (15:10 UTC) and reached ~15,000 ft (4.5 km) above sea level. The National Weather Service issued a SIGMET for these events and suggested a maximum cloud height of 25,000 ft (7.6 km) above sea level for the drifting ash cloud. Web camera images and pilot reports show continued low-level ash emissions this morning including a small ash cloud near the summit around 10:30 am AKDT (18:30 UTC).  

Eruptions from Shishaldin have produced minor and on occasion significant ash clouds in the past.  These can occur with little warning. Shishaldin is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network is partially impaired, therefore AVO is also using nearby geophysical networks, satellite data and regional infrasound and lighting data to detect activity. AVO will continue to closely monitor unrest at Shishaldin Volcano. 

Strongly elevated surface temperatures continue to be observed at the summit of Shishaldin Volcano in satellite data. Incandescence at the summit was observed in web camera images from last night and sulfur dioxide was detected in satellite data over the past day. In addition, seismic tremor amplitudes have increased over the past day. Together, these observations suggest that lava is likely present within the summit crater of Shishaldin. In response, the Alaska Volcano Observatory is raising the Aviation Color Code to ORANGE and the Alert Level to WATCH.  

Shishaldin is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network is partially impaired, therefore AVO is also using nearby geophysical networks, satellite data and regional infrasound and lighting data to detect activity. AVO will continue to closely monitor unrest at Shishaldin Volcano. 

Strongly elevated surface temperatures at the summit of Shishaldin Volcano have been observed in satellite data over the past day. Intermittent tremor and low-frequency earthquakes over the past week have gradually become more regular and consistent in the past day. In response, the Alaska Volcano Observatory is raising the Aviation Color Code to YELLOW and the Alert Level to ADVISORY. These observations represent a departure from normal background activity at Shishaldin, but do not necessarily indicate that an eruption will occur. Shishaldin is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network is partially impaired, therefore AVO is also using nearby geophysical networks, satellite data and regional infrasound and lighting data to detect activity. AVO will continue to closely monitor unrest at Shishaldin Volcano.
 

Kīlauea is no longer erupting. Lava supply to the Halemaʻumaʻu lava lake ceased on June 19 based upon lava lake levels and behavior of the crater floor. Sulfur dioxide emissions have decreased to near pre-eruption background levels.   

Accordingly, the USGS Hawaiian Volcano Observatory (HVO) is lowering the Volcano Alert Level for ground-based hazards from WATCH to ADVISORY and the Aviation Color Code from ORANGE to YELLOW.  

Seismic activity—including eruptive tremor—in the summit region has been low since the eruption ceased. Over that period, gradual inflation has been recorded at summit tiltmeters. Overnight webcam views showed some incandescence from previously erupted lava as the lava proceeds to cool. There remains the potential for eruptive activity to resume in the near future at or near the summit of Kīlauea with little or no warning.

HVO continues to closely monitor Kīlauea for signs of renewed activity. Should volcanic activity change significantly, a new Volcanic Activity Notice will be issued. 

Hazards are still present on Kīlauea and are described below. Residents and visitors should stay informed and follow County of Hawai‘i and Hawaiʻi Volcanoes National Park guidelines. 

For more information about the meaning of aviation color codes, see https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes 

HVO is lowering Kīlauea’s volcano alert level from WARNING to WATCH because the initial high effusion rates have declined, and no infrastructure is threatened.  Associated hazards are confined to the closed area established by Hawaiʻi Volcanoes National Park.

HVO is lowering Kīlauea’s aviation color code from RED to ORANGE because there is currently no threat of significant volcanic ash emission into the atmosphere outside of the hazardous closed area within Hawai‘i Volcanoes National Park. The eruption plume continues to rise to the base of the inversion level at about 8,000-10,000 feet above sea level as it did yesterday.  The plume is largely composed of sulfur dioxide gas and minor volcanic particles, but in lower concentrations due to the drop in effusion rate.  Hazards associated with the eruption are limited and are described below. 

Kīlauea’s summit eruption is expected to continue and remain confined to Halemaʻumaʻu crater within Hawai‘i Volcanoes National Park.  HVO does not see any indication of activity migrating elsewhere on Kīlauea volcano and expects the eruption to remain confined to the summit region. 

HVO will continue to monitor this activity closely and report any significant changes in future notices. 

Kīlauea volcano is erupting. At approximately 4:44 a.m. HST on June 7, 2023, the USGS Hawaiian Volcano Observatory detected glow in Kīlauea summit webcam images indicating that an eruption has commenced within Halemaʻumaʻu crater in Kīlauea’s summit caldera, within Hawai‘i Volcanoes National Park.

The USGS Hawaiian Volcano Observatory is elevating Kīlauea’s volcano alert level from WATCH to WARNING and its aviation color code from ORANGE to RED as this eruption and associated hazards are evaluated.  

The opening phases of eruptions are dynamic. Webcam imagery shows fissures at the base of Halemaʻumaʻu crater generating lava flows on the surface of the crater floor. The activity is confined to Halemaʻumaʻu and the hazards will be reassessed as the eruption progresses.

HVO will continue to monitor this activity closely and report any significant changes in future notices.

HVO is in constant communication with Hawai‘i Volcanoes National Park as this situation evolves. The activity is confined entirely within the park.

Kīlauea volcano is not erupting. Increased earthquake activity and changes in the patterns of ground deformation at Kīlauea’s summit began occurring the evening of June 6, 2023, indicating movement of magma in the subsurface.

The USGS Hawaiian Volcano Observatory is raising the volcano alert level/aviation color code for Kīlauea from ADVISORY/YELLOW to WATCH/ORANGE due to this activity.

At this time, it is not possible to say with certainty if this activity will lead to an eruption; the activity may remain below ground. However, an eruption in Kīlauea’s summit region, within Hawai‘i Volcanoes National Park and away from infrastructure, is one potential outcome. Based on patterns of earthquake activity and ground deformation, it is likely that any new eruptive activity will occur in Halemaʻumaʻu crater, within the closed area of Hawaiʻi Volcanoes National Park. 

HVO will continue to monitor this activity closely and adjust the alert level accordingly.

HVO is in constant communication with Hawai‘i Volcanoes National Park as this situation evolves. The activity is confined entirely within the park.

Previously reported earthquake activity culminated in an ice-rock avalanche slightly before 5:14 pm AKDT this evening (1:14 June 6, 2023 UTC). Although we lack visual confirmation at this time, the seismic signals recorded match historic observations of avalanches associated with Red Glacier on Iliamna Volcano’s eastern flank. Seismicity has since declined to background levels. The Aviation Color Code and Volcano Alert Level is therefore being lowered to GREEN and NORMAL.

An increase in seismicity has been observed at Iliamna volcano beginning at about 12:00 pm AKDT June 5, 2023 (20:00 UTC). The rate of earthquakes initially occurred in 1 minute intervals and have been becoming more closely spaced. There is a possibility that the earthquakes may be related to magmatic movement or hydrothermal fluids beneath the volcano. However, similar activity has been observed before large mass movements or avalanches at Iliamna volcano, and AVO cannot rule out either possibility at this time.

Due to the seismicity at Iliamna being above background levels the Aviation Color Code and Volcano Alert level for Iliamna are being raised to YELLOW and ADVISORY.

Signals consistent with eruptive activity at Ahyi seamount began to be observed in underwater pressure sensors at Wake Island beginning on May 21, 2023, at about 10:10 PM ChST (12:10 PM UTC) and are continuing. A plume of discolored sea water was observed above the area of the previously active vent in a satellite image on May 22, 2023, at 10:43 AM ChST (00:43 UTC). Due to this renewed activity at Ahyi Seamount The Aviation Color Code and Volcano Alert Level are being raised to YELLOW/ADVISORY. 

Starting mid-October 2022, hydroacoustic sensors at Wake Island, 1,410 miles (2,270 km) east of Ahyi, began recording signals consistent with activity from an undersea volcanic source. In collaboration with the Laboratoire de Geophysique in Tahiti, a combined analysis of the hydroacoustic signals and data from seismic stations located at Guam and Chichijima Island, Japan, confirmed that the source of this activity was at or near Ahyi seamount.  Observations of discolored water above the seamount in satellite data confirmed activity at Ahyi. The activity appears to have paused beginning in early April but has now resumed.  

The level of eruptive activity at Semisopochnoi has declined in the past week. The last evidence of ash emissions from the volcano was observed on May 5 and consisted of a light dusting of ash on the northwest flank of Mount Young. The Aviation Color Code and Volcano Alert Level are being lowered to YELLOW/ADVISORY.

Small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Young and ash clouds usually under 10,000 ft (3 km) above sea level have characterized the recent activity and more ash-producing events could occur again with little warning.  

Semisopochnoi is monitored by a local seismic and infrasound network, local web cameras, regional lightning and infrasound sensors, and satellite data. 

Signs of unrest at Ahyi Seamount have diminished and nothing indicative of submarine volcanic activity has occurred for at least four weeks. Hydroacoustic detection of underwater volcanic activity has been negligible since early April 2023 and satellite observations of discolored water near the seamount were last noted in late March 2023. 

Starting mid-October 2022, hydroacoustic sensors at Wake Island, 2,270 km (1,410 miles) east of Ahyi, began recording signals consistent with activity from an undersea volcanic source. In collaboration with the Laboratoire de Geophysique in Tahiti, a combined analysis of the hydroacoustic signals and data from seismic stations located at Guam and Chichijima Island, Japan, confirmed that the source of this activity was at or near Ahyi seamount. Hydrophone signals indicative of submarine volcanic activity are no longer detected.

Due to the apparent abscence of activity, the aviation color code is being lowered from YELLOW to UNASSIGNED and the alert level is being lowered from ADVISORY to UNASSIGNED. 

Kīlauea is no longer erupting. Lava supply to the Halemaʻumaʻu lava lake ceased on March 7 based upon lava lake levels and behavior of the crater floor. Sulfur dioxide emissions have decreased to near pre-eruption background levels.   

Accordingly, the USGS Hawaiian Volcano Observatory (HVO) is lowering the Volcano Alert Level for ground-based hazards from WATCH to ADVISORY and the Aviation Color Code from ORANGE to YELLOW.  

Seismicity and deformation patterns remain unsettled. Resumption of eruptive activity may occur in the near future with little or no warning. Potential remains for resumption of this eruption or initiation of a new eruption at or near the summit of Kīlauea. 
 
HVO continues to closely monitor Kīlauea for signs of renewed activity. Should volcanic activity change significantly, a new Volcanic Activity Notice will be issued. 

Hazards are still present on Kīlauea and are described below. Residents and visitors should stay informed and follow County of Hawai‘i and Hawaiʻi Volcanoes National Park guidelines. 

For more information about the meaning of aviation color codes, see https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes 

Low-level ash emissions from the north crater of Mount Young at Semisopochnoi were observed in several web camera images over the past day. In addition, small explosions and volcanic tremor have resumed during the same time period. Ash emissions have not been detected in satellite data, although a vapor plume extending 150 km (90 miles) from Mount Young was observed yesterday in satellite data. This activity is similar to eruptive activity observed intermittently over the last few years at Semisopochnoi. The Aviation Color Code and Volcano Alert Level are being raised to ORANGE/WATCH.  

Small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Cerberus and ash clouds usually under 10,000 ft (3 km) above sea level have characterized the recent activity and more ash-producing events could occur again with little warning.  

Semisopochnoi is monitored by a local seismic and infrasound network, local web cameras, regional lightning and infrasound sensors, and satellite data. 

Mauna Loa has been quiet for the past three months since the eruption ended on December 13, 2022.   The number of earthquakes beneath Mauna Loa's summit has returned to background levels.  Inflation of Mauna Loa continues as magma replenishes the summit magma chamber.

Accordingly, the USGS Hawaiian Volcano Observatory (HVO) is lowering the Volcano Alert Level for ground-based hazards from ADVISORY to NORMAL and the Aviation Color Code from YELLOW to GREEN. 

In conjunction with this change, Mauna Loa updates will change from weekly to monthly, with the next monthly update on April 6, 2023.
 

For more information about the meaning of aviation color codes, see https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes 

Earthquake activity near Tanaga Volcano has decreased in both rate and magnitude from the peak of the swarm on March 9 – 11. The significant decline in earthquake activity decreases the potential for an eruption at the volcano. No other signs of unrest have been detected in other monitoring data. AVO is therefore lower the Aviation Color Code to Yellow and the Volcano Alert Level to ADVISORY. 

Seismic activity has also declined at Takawangha volcano, which is about 8 km (5 miles) east of Tanaga Volcano on Tanaga Island. The Aviation Color Code/Alert Level has also been lowered to YELLOW/ADVISORY for Takawangha. 

AVO continues to monitor the activity closely and seismic analysts are locating events as time permits. Earthquakes are occurring under Tanaga Island at a rate of up to several per minute. The largest event over the past 24 hours was a M3.1 located between Takawangha volcano and Tanaga Volcano.

Tanaga is monitored with a local seismic network, a single local infrasound sensor, regional infrasound and lightning sensors, and satellite imagery.  

For current monitoring data: https://avo.alaska.edu/activity/Tanaga.php

Earthquake activity near Takawangha volcano has decreased in both rate and magnitude from the peak of the swarm on March 9 – 11. The significant decline in earthquake activity decreases the potential for an eruption at the volcano. No other signs of unrest have been detected in other monitoring data. AVO is therefore lower the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY. 

Seismic activity has also declined at Tanaga Volcano, which is about 8 km (5 miles) west of Takawangha on Tanaga Island. The Aviation Color Code/Alert Level has also been lowered to YELLOW/ADVISORY for Tanaga Volcano. 

AVO continues to monitor the activity closely and seismic analysts are locating events as time permits. Earthquakes are occurring under Tanaga Island at a rate of up to several per minute. The largest event over the past 24 hours was a M3.1 located between Takawangha volcano and Tanaga Volcano. 

Takawangha is monitored with a local seismic network, a single local infrasound sensor, regional infrasound and lightning sensors, and satellite imagery.  

For current monitoring data: https://avo.alaska.edu/activity/Takawangha.php

Over the past 48 hours, earthquake activity near Takawangha volcano has been elevated and continues. This sustained activity indicates an increased potential for eruption at the volcano. Therefore AVO is raising the Aviation Color Code to ORANGE and the Volcano Alert Level to WATCH.

Seismic activity is also elevated at Tanaga Volcano, which is about 8 km (5 miles) west of Takawangha on Tanaga Island. If an eruption were to occur, it is uncertain at this stage if it would come from Takawangha or Tanaga. 

AVO analysts continue to monitor the situation closely, and locate events as time permits. Earthquakes are occurring under Tanaga Island at a rate of up to several per minute. The largest event over the past 24 hours was a M3.9 located under Tanaga Volcano. 

No eruptive activity or signs of unrest have been detected in satellite or other monitoring data.

Takawangha is monitored with a local seismic network, a single local infrasound sensor, regional infrasound and lightning sensors, and satellite imagery.  

For current monitoring data: https://avo.alaska.edu/activity/Takawangha.php

Over the past 48 hours, earthquake activity near Tanaga Volcano has been elevated and continues. This sustained activity indicates an increased potential for eruption at the volcano. Therefore AVO is raising the Aviation Color Code to ORANGE and the Volcano Alert Level to WATCH.

Seismic activity is also elevated at Takawangha volcano, which is about 8 km (5 miles) east of Tanaga on Tanaga Island. If an eruption were to occur, it is uncertain at this stage if it would come from Tanaga or Takawangha. 

AVO analysts continue to monitor the situation closely, and locate events as time permits. Earthquakes are occurring under Tanaga Island at a rate of up to several per minute. The largest event over the past 24 hours was a M3.9 located under Tanaga Volcano. 

No eruptive activity or signs of unrest have been detected in satellite or other monitoring data.

Tanaga is monitored with a local seismic network, a single local infrasound sensor, regional infrasound and lightning sensors, and satellite imagery.  

For current monitoring data: https://avo.alaska.edu/activity/Tanaga.php

Earthquake activity beneath Tanaga Volcano began to increase slowly starting at about 1:30 PM AKST today.  At roughly 8:45 PM AKST this evening, the activity escalated with earthquakes occurring as often as 2 or 3 each minute.  Initial locations of these earthquakes place them at shallow depths beneath the summit of Tanaga Volcano, and the largest of these earthquakes have magnitudes between 2 and 3. In response to this increase in seismicity, we are raising the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.

Tanaga Volcano is monitored with a local seismic and infrasound network, regional infrasound and lightning detection networks, and satellite data.

The number of earthquakes beneath Aniakchak volcano has recently increased and shifted to shallower depths. Due to this increase in seismic activity to above-background levels, the Alaska Volcano Observatory is raising the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.  There have been no signs of unrest in other monitoring data. 

Background seismicity at Aniakchak has mostly been characterized by deep (>15 km or 9.3 miles), long-period events occurring at a rate of ~4 earthquakes per month. From October 2022 to present, the rate of earthquakes has been more elevated and characterized by shallower earthquakes at depths less than 9 km (5.6 miles) below sea level. The earthquake rate has further increased since January 31 with dozens of earthquakes detected per day, including a M3.7 earthquake on February 17. 

There is no indication that an eruption of Aniakchak is imminent, or that one will occur. Increases in seismic activity have been detected previously at other similar volcanoes, with no subsequent eruptions. We expect additional shallow seismicity and other signs of unrest, such as gas emissions, elevated surface temperatures, and surface deformation to precede any future eruption, if one were to occur. Should activity increase, AVO will issue further notices.   

AVO monitors Aniakchak with a local network, which consists of six seismometers, a web camera, and a single infrasound sensor, as well as satellite remote sensing data and regional infrasound and lightning networks. To view current monitoring data, see https://avo.alaska.edu/activity/Aniakchak.php 

Earthquake activity beneath Trident Volcano has recently increased and is ongoing, although there have been no signs of unrest in other monitoring data. Due to this increase in seismic activity to above-background levels, the Alaska Volcano Observatory is raising the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.  

The current period of seismic unrest, or earthquake swarm, began on August 24, 2022. Earthquake depths at the beginning of the swarm were mostly deep, around 25 km (16 miles) below sea level, and became progressively shallower to around 5 km (3 miles) over the following four days. Since late August 2022, most earthquakes have been located in the shallow crust, with depths less than 6 km below sea level. Since January 1, 2023, earthquakes under Trident are occurring at an average rate of about ten per day. The largest event since August was a M4.6 quake on November 20, but most earthquakes are much smaller. A few episodes of weak seismic tremor and low frequency earthquakes have also occurred.  

Within the Katmai group of volcanoes, earthquakes are typically clustered in three regions: under Trident Volcano, under Mount Katmai to the east, and under Martin and Mageik volcanoes to the west. The current period of seismic unrest is most prominent in the area under Trident, but the rate of earthquakes has also increased in the region beneath Martin and Mageik volcanoes. Because of the initial sequence of deep earthquakes and continued episodes of tremor under Trident, it is most likely, though not certain, that the unrest observed in the area is due to movement of magma or magmatic fluids at depth there. 

There is no indication that an eruption of Trident is imminent, or that one will occur. Increases in seismic activity have been detected previously at Trident and other similar volcanoes, with no subsequent eruptions. We expect additional shallow seismicity and other signs of unrest, such as gas emissions, elevated surface temperatures, and surface deformation to precede any future eruption, if one were to occur. Should activity increase, AVO will issue further notices.  

AVO monitors Trident with a local network of seismometers, a webcam, remote sensing data, and regional infrasound and lightning networks. To view current monitoring data, see https://avo.alaska.edu/activity/Trident.php 

Although the active north cone of Mount Young continues to produce a robust steam plume, no ash emissions or explosive activity have been detected at Semisopochnoi volcano since late January. The level of seismic activity has also decreased, with no significant seismic tremor observed since January 25th. Thus, we are lowering the Aviation Color Code to YELLOW and Volcano Alert Level to ADVISORY.  

Small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Young, and ash clouds usually under 10,000 ft (3 km) above sea level, have characterized the recent activity at Semisopochnoi. More ash-producing events could occur again with little warning.  

Semisopochnoi is monitored by a local seismic and infrasound network, local web cameras, regional lightning and infrasound sensors, and satellite data.  

Eruptive activity at Pavlof Volcano has stopped. Seismicity has decreased to background levels, and no explosions have been detected since December 11, 2022.  Weakly elevated surface temperatures and minor steaming from the recently active vent continue to be observed intermittently in satellite and web camera imagery, consistent with cooling of previously erupted lava. Due to the decrease in activity to background levels, we are lowering the Aviation Color Code to Green and the Volcano Alert Level to Normal.

Previous eruptions of Pavlof indicate that the level of unrest can change quickly and eruptive activity could resume with little or no warning. Pavlof is monitored by local seismic and infrasound sensors, satellite data, web cameras, and regional infrasound and lightning networks. 

Kīlauea’s summit eruption continues and is confined to Halemaʻumaʻu crater within Hawai‘i Volcanoes National Park.  HVO does not see any indication of activity migrating elsewhere on Kīlauea volcano and expects the eruption to remain confined to the summit region. 

HVO is lowering Kīlauea’s volcano alert level from WARNING to WATCH because the initial high effusion rates are declining, and no infrastructure is threatened. HVO is lowering Kīlauea’s aviation color code from RED to ORANGE because there is currently no threat of significant volcanic ash emission into the atmosphere outside of the hazardous closed area within Hawai‘i Volcanoes National Park. Hazards associated with the eruption are limited and are described below. 

HVO will continue to monitor this activity closely and report any significant changes in future notices. 

Kīlauea volcano is erupting. At approximately 4:34 p.m. HST on January 5, 2023, the USGS Hawaiian Volcano Observatory detected glow in Kīlauea summit webcam images indicating that the eruption has resumed within Halemaʻumaʻu crater in Kīlauea’s summit caldera, within Hawai‘i Volcanoes National Park.

The USGS Hawaiian Volcano Observatory is elevating Kīlauea’s volcano alert level from WATCH to WARNING and its aviation color code from ORANGE to RED as this eruption and associated hazards are evaluated.  

The opening phases of eruptions are dynamic. Webcam imagery shows fissures at the base of Halemaʻumaʻu crater generating lava flows on the surface of the crater floor. The activity is confined to Halemaʻumaʻu and the hazards will be reassessed as the eruption progresses.

HVO will continue to monitor this activity closely and report any significant changes in future notices.

HVO is in constant communication with Hawai‘i Volcanoes National Park as this situation evolves. The activity is confined entirely within the park.

Kīlauea volcano is not erupting. Increased earthquake activity and changes in the patterns of ground deformation at Kīlauea’s summit began occurring in the early morning of January 5, 2023, indicating movement of magma in the subsurface. At this time, it is not possible to say with certainty if this activity will lead to an eruption; the activity may remain below ground. However, an eruption in Kīlauea’s summit region, within Hawai‘i Volcanoes National Park and away from infrastructure, is one potential outcome.

The USGS Hawaiian Volcano Observatory is raising the volcano alert level/aviation color code for Kīlauea from Advisory/Yellow to Watch/Orange due to this activity.

HVO will continue to monitor this activity closely and adjust the alert level accordingly.

HVO is in constant communication with Hawai‘i Volcanoes National Park as this situation evolves. The activity is confined entirely within the park.

A sustained reduction of volcanic unrest at Cleveland Volcano over the past few months has prompted the Alaska Volcano Observatory to downgrade the Aviation Color Code and Volcano Alert Level from YELLOW/ADVISORY to UNASSIGNED/UNASSIGNED.

Elevated surface temperatures and sulfur dioxide emissions prompted raising the Aviation Color Code and Volcano Alert Level from UNASSIGNED/UNASSIGNED to YELLOW/ADVISORY on May 11, 2022. This activity continued throughout the summer, but all signs of unrest have ceased or declined in recent months. Elevated surface temperatures in the summit crater are occasionally being observed but at reduced frequency and strength. Sulfur dioxide emissions have not been detected in satellite data since July 29, 2022. The last eruptive activity at Cleveland volcano was a short-lived explosion on the evening (local time) of June 1, 2020.

Despite the current pause, the eruptive period at Cleveland, dating back to 2001, remains ongoing and future explosions are likely. These occur without warning and typically generate small clouds of volcanic ash that are a hazard in the immediate vicinity of the volcano, though more significant ash emissions are possible.

Cleveland volcano is monitored with a limited real-time seismic network. This smaller network inhibits AVO's ability to detect precursory unrest that may lead to an explosive eruption. Rapid detection of an ash-producing eruption may be possible using a combination of seismic, infrasound, lightning, and satellite data.

Ash emissions resumed over the past 24 hours at the active north crater of Mount Cerberus. Minor ash deposits on the flanks of Mount Cerberus were observed on fresh snow extending up to ~1 km (~1000 yards) from the vent in web camera images over the past day. No ash plumes have been observed in web camera or satellite imagery, but a persistent steam plume rising up to 5,000 ft above sea level from the active crater may now be carrying minor volcanic ash within it. The observation of ash deposits follows increased seismicity, including seismic tremor, in the past week. This activity is similar to eruptive activity observed over the past year at Semisopochnoi, but not since November 7. The Alaska Volcano Observatory is therefore raising the Aviation Color Code to ORANGE and Volcano Alert Level to WATCH. 

Small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Cerberus and ash clouds usually under 10,000 ft (3 km) above sea level have characterized the recent activity and more ash-producing events could occur again with little warning. 

Semisopochnoi is monitored by a local seismic and infrasound network, local web cameras, regional lightning and infrasound sensors, and satellite data. 

Eruptive activity at Pavlof Volcano has paused. Although seismicity remains above background levels with intermittent seismic tremor, no explosions have been detected since December 7, 2022.  No elevated surface temperatures or incandescent lava have been observed in satellite and webcam images since December 2. Due to this decrease in activity, we are lowering the Aviation Color Code to YELLOW and Volcano Alert Level to ADVISORY.

Previous eruptions of Pavlof indicate that the level of unrest can change quickly and eruptive activity could resume with little or no warning. Pavlof is monitored by local seismic and infrasound sensors, satellite data, web cameras, and regional infrasound and lightning networks. 

Mauna Loa is no longer erupting. Lava supply to the fissure 3 vent on the Northeast Rift Zone ceased on December 10 and sulfur dioxide emissions have decreased to near pre-eruption background levels. Volcanic tremor and earthquakes associated with the eruption are greatly diminished.

Accordingly, the USGS Hawaiian Volcano Observatory (HVO) is lowering the Volcano Alert Level for ground-based hazards from WATCH to ADVISORY and the Aviation Color Code from ORANGE to YELLOW. 

Spots of incandescence may remain near the vent, along channels, and at the flow front for days or weeks as the lava flows cool. However, eruptive activity is not expected to return based on past eruptive behavior. Summit and Northeast Rift Zone inflation continues. 
 
HVO continues to closely monitor Mauna Loa for signs of renewed activity. Should volcanic activity change significantly a new Volcanic Activity Notice will be issued immediately. 
 
Residents and visitors should stay informed and follow County of Hawai‘i and Hawaiʻi Volcanoes National Park guidelines. 

For more information about the meaning of aviation color codes, see https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes 

Kīlauea is no longer erupting. Lava supply to the Halemaʻumaʻu lava lake ceased on December 9 based upon lava lake levels and behavior of the crater floor. Sulfur dioxide emissions have decreased to near pre-eruption background levels.   

Accordingly, the USGS Hawaiian Volcano Observatory (HVO) is lowering the Volcano Alert Level for ground-based hazards from WATCH to ADVISORY and the Aviation Color Code from ORANGE to YELLOW.  

Seismicity and deformation patterns remain unsettled. Potential remains for resumption of this eruption or initiation of a new eruption at or near the summit of Kīlauea. 
 
HVO continues to closely monitor Kīlauea for signs of renewed activity. Should volcanic activity change significantly a new Volcanic Activity Notice will be issued. 

Hazards are still present on Kīlauea and are described below. Residents and visitors should stay informed and follow County of Hawai‘i and Hawaiʻi Volcanoes National Park guidelines. 

For more information about the meaning of aviation color codes, see https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes 

Lava eruption from fissure 3 on the Northeast Rift Zone of Mauna Loa continues, but the threat to aviation of significant volcanic ash emission into the atmosphere has passed. For this reason, HVO is reducing the aviation color code from RED to ORANGE.   

The ground-based volcano alert level will remain at WARNING, reflecting the ongoing hazards of the fissure 3 lava flow. Lava flows are slowly moving north toward Daniel K. Inouye Highway and are spreading out and inflating (thickening) as they advance over low-sloping ground. The fronts of lava flows can break open unexpectedly, sending flows in several directions. Rain on lava creates steam and reduces visibility. If visiting the County of Hawai'i public viewing area, remain with your vehicle and do not approach the flows. 

The Federal Aviation Administration has issued a temporary flight restriction extending from the surface to 1500 feet (457 meters) above ground level in the eruption area. See: https://tfr.faa.gov/save_pages/detail_2_9210.html 

For more information about the meaning of aviation color codes, see https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes 

Signs of unrest at Ahyi Seamount have been observed in satellite and remote geophysical data.  A plume of discolored water above Ahyi Seamount has been visible persistently in satellite data since November 18, 2022. This discoloration could be due to degassing or eruption at the volcano, but we cannot say for certain due to a lack of local monitoring stations. 

Starting in mid-October, hydroacoustic sensors at Wake Island, 2,270 km (1,410 miles) east of Ahyi, began recording signals consistent with activity from an undersea volcanic source. In collaboration with the Laboratoire de Geophysique in Tahiti, recent combined analysis of the hydroacoustic signals together with data from seismic stations located at Guam and Chichijima Island, Japan, confirm that the source of this activity is at or near Ahyi seamount.  Hydrophone signals continue to be observed but have decreased in the past few weeks.  

Due to the current activity, the aviation color code is being raised from UNASSIGNED to YELLOW and the alert level is being raised from UNASSIGNED to ADVISORY. 

The eruption of Mauna Loa has migrated from the summit to the Northeast Rift Zone where fissures are feeding several lava flows. HVO staff on an overflight at approximately 6:30 a.m. HST confirmed fissures at high elevations within Hawai‘i Volcanoes National Park are feeding lava flows upslope of the Mauna Loa Weather Observatory. Lava flows are not threatening any downslope communities and all indications are that the eruption will remain in the Northeast Rift Zone. Volcanic gas and possibly fine ash and Pele's Hair may be carried downwind.

Residents at risk from Mauna Loa lava flows should review preparedness and refer to Hawai‘i County Civil Defense information for further guidance.    

Based on past events, the early stages of a Mauna Loa rift zone eruption can be very dynamic, and the location and advance of lava flows can change rapidly.    

HVO is in close consultation with emergency management partners and will monitor the volcano closely to provide further updates on activity.  

At approximately 11:30 p.m. HST this evening, November 27, an eruption began in Moku‘āweoweo, the summit caldera of Mauna Loa, inside Hawai‘i Volcanoes National Park. At this time, lava flows are contained within the summit area and are not threatening downslope communities.  Winds may carry volcanic gas and possibly fine ash and Pele’s hair downwind.

Residents at risk from Mauna Loa lava flows should review preparedness and refer to Hawai‘i County Civil Defense information for further guidance. 

Based on past events, the early stages of a Mauna Loa eruption can be very dynamic and the location and advance of lava flows can change rapidly.    

If the eruption remains in Moku‘āweoweo, lava flows will most likely be confined within the caldera walls.  However, if the eruptive vents migrate outside its walls, lava flows may move rapidly downslope.   

HVO is in close consultation with emergency management partners and will be monitoring the volcano closely to provide further updates on activity.  As soon as possible, HVO will conduct aerial reconnaissance to better describe the eruption and assess hazards.    

Although the active north cone of Mount Cerberus continues to produce a vapor plume and elevated seismicity, no ash emissions or explosive activity have been detected at Semisopochnoi volcano since November 7th. The level of seismic activity is still elevated but has decreased. Thus, we are lowering the Aviation Color Code to YELLOW and Volcano Alert Level to ADVISORY. 

Small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Cerberus and ash clouds usually under 10,000 ft (3 km) above sea level have characterized the recent activity and more ash-producing events could occur again with little warning. 

Semisopochnoi is monitored by a local seismic and infrasound network, local web cameras, regional lightning and infrasound sensors, and satellite data. 

The number of small earthquakes detected near Takawangha volcano has increased over the past few days and has intensified over the past 24 hours. The earthquakes, the largest with magnitudes between 2 and 3, have preliminary depths of about 2 to 4 miles (3 to 6 km) below sea level. This activity may be due to the movement of magma beneath the volcano. It marks a departure from background activity and therefore AVO is raising the Aviation Color Code to YELLOW and Alert Level to ADVISORY for Takawangha volcano.

No eruptive activity has been detected in satellite or other monitoring data.

Takawangha is monitored with a local seismic network, a single local infrasound sensor, regional infrasound and lightning sensors, and satellite imagery.  

Small explosions have been detected in geophysical data over the past week from the north crater of Mount Cerberus at Semisopochnoi. In addition, volcanic tremor has resumed during the same time period. Ash emissions have not been observed. However, the type of unrest we detected was associated with ash emissions during previous periods of unrest and, if occurring, such ash emissions are likely below 10,000 ft above sea level. These events are similar to eruptive activity observed over the last year at Semisopochnoi, but not since September 14. The Aviation Color Code and Volcano Alert Level are being raised to ORANGE/WATCH.

Small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Cerberus and ash clouds usually under 10,000 ft (3 km) above sea level have characterized the recent activity and more ash-producing events could occur again with little warning. 

Semisopochnoi is monitored by a local seismic and infrasound network, local web cameras, regional lightning and infrasound sensors, and satellite data. 

The swarm of earthquakes that began on August 24, 2022, beneath Trident Volcano has subsided and seismic tremor has not been observed since September 30, 2022. Occasional local earthquakes continue to be detected at background levels. Due to this decrease in activity and the absence of other signs of unrest, we are lowering the Aviation Color Code to GREEN and the Volcano Alert level to NORMAL.

Should activity increase, AVO will issue further notices. AVO monitors Trident with a local network of seismometers, a webcam, remote sensing data, and regional infrasound and lightning networks. To view current monitoring data, see https://avo.alaska.edu/activity/Trident.php 

Although the active north cone of Mount Cerberus continues to produce a vapor plume and elevated seismic tremor, no ash emissions or explosive activity have been detected at Semisopochnoi volcano since September 14. The level of seismic activity is still elevated but has decreased. Thus, we are lowering the Aviation Color Code to YELLOW and Volcano Alert Level to ADVISORY. 

Small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Cerberus and ash clouds usually under 10,000 ft (3 km) above sea level have characterized the recent activity. More ash-producing events could occur again with little warning.  

Semisopochnoi is monitored by a local seismic and infrasound network, local web cameras, regional lightning and infrasound sensors, and satellite data. 

The swarm of earthquakes that began on August 24, 2022, beneath Trident volcano continues. In addition, episodes of weak seismic tremor and low frequency earthquakes have been detected since August 28. Together, these observations mean that Trident is exhibiting signs of elevated unrest above known background level. Therefore, we are raising the Aviation Color Code to YELLOW and the Volcano Alert level to ADVISORY. 

During the current swarm, earthquake depths were initially mostly deep at around 25 km (16 miles) below sea level but became progressively shallower to around 5 km (3 miles) by August 28. Since then, earthquakes have mostly occurred 3 to 6 km (about 2 to 4 miles) below sea level, although some deeper events have been detected. Earthquake magnitudes (M) have ranged from M –0.7 to M 1.9. At the peak of the swarm, dozens of earthquakes occurred daily beneath the volcano, but earthquake rates have since decreased to just a few per day. No other signs of unrest have been detected in monitoring data. 

The increase in seismic activity is likely caused by movement of magma or magmatic fluids. Increases in seismic activity have been detected previously at Trident and other similar volcanoes, with no subsequent eruptions. We expect additional shallow seismicity and other signs of unrest, such as gas emissions, elevated surface temperatures, and surface deformation to precede any future eruption, if one were to occur. 

Should activity increase, AVO will issue further notices. AVO monitors Trident with a local network of seismometers, a webcam, remote sensing data, and regional infrasound and lightning networks. To view current monitoring data, see https://avo.alaska.edu/activity/Trident.php 

Several seismic stations in the Shishaldin network are now operating after being offline over the past year. Data from these stations have improved the Alaska Volcano Observatory's monitoring capability, and allows for location of small local earthquakes. Thus, the Aviation Color Code is now GREEN and the Volcano Alert Level NORMAL. The Alaska Volcano Observatory continues to monitor Shishaldin with the local seismic, infrasound, GPS, and tilt stations, web camera images, remote infrasound and lightning networks, and satellite images.

Ofu-Olosega Islands volcano has been ruled out as the source of the ongoing Manuʻa Islands earthquake swarm. Data from seismometers installed in the Manuʻa Islands this week confirms that the ongoing earthquake activity is related to Taʻū Island volcano and not Ofu-Olosega. Accordingly, the USGS is lowering the volcano alert level to NORMAL and the aviation color code to GREEN for Ofu-Olosega. Taʻū Island remains at ADVISORY/YELLOW.

Due to the closeness of the Ofu-Olosega Islands to Taʻū Island, residents of Ofu-Olosega could still be significantly affected by events that may take place on or around Taʻu Island. The earthquake swarm is still ongoing, and people on Ofu-Olosega are likely to feel shaking from future events. Residents of Ofu-Olosega can now find updates on relevant hazards and other important information in the Daily Reports for Taʻū Island. Possible hazards that could impact residents of Ofu-Olosega include shaking related to strong, damaging earthquakes, local tsunamis or large waves related to underwater volcanic activity or landslides, and/or ash and gas from volcanic eruptions.

USGS scientists continue to monitor the earthquake swarm with six microseismometers placed on Tutuila, Taʻū, and Olosega Islands and two more sensitive seismometers on Taʻū and Ofu Islands. We are working to bring a third advanced seismometer online on eastern Ta’u Island.

To keep receiving information about the ongoing earthquake crisis in American Samoa, subscribe to the Volcano Notification Service (https://volcanoes.usgs.gov/vns2/)
and select Taʻū Island from the volcano list.

Samoan and English language alert level and color code definitions: (PDF download, 57.68 kb) https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/media/files/VOLCANO%20AVIATION%20CODES%20AND%20ALERT%20LEVELS.pdf

A short-lived explosion occured at 1:47 PM AKDT (21:47 UTC) today that produced ash emissions observed in local webcams. Ash emissions ceased by 2:16 PM AKDT (22:16 UTC). The ash plume was not visible above the meteorological clouds in satellite images, thus was below 20,000 ft. (6 km) above sea level. This event is similar to eruptive activity observed over the last year at Semisopochnoi, but not since June 12. The Aviation Color Code and Volcano Alert Level are being raised to ORANGE/WATCH.

Small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Cerberus and ash clouds usually under 10,000 ft (3 km) above sea level have characterized the recent activity and more ash-producing events could occur again with little warning. 

An earthquake swarm is occurring in the Manuʻa Islands of American Samoa. As the federal entity responsible for monitoring earthquakes and volcanoes in American Samoa, the U.S. Geological Survey Hawaiian Volcano Observatory (HVO) is assigning the Taʻū Island and Ofu-Olosega Volcano Alert Levels to ADVISORY and Aviation Color Codes YELLOW. The designation previously was UNASSIGNED. This designation does not reflect a change in the behavior of either volcano; it simply acknowledges that the number, size, and frequency of earthquakes being felt by people on Taʻū Island and Ofu-Olosega are well above typical background activity (a NORMAL/GREEN alert level). The first reports of felt earthquakes occurred on July 26, 2022. Personal reports and instruments installed over the past week confirm the continuation of elevated earthquake activity.

Data analysis from simple earthquake detection equipment installed on Tutuila, Taʻū, and Ofu-Olosega Islands indicate that the earthquakes are occurring beneath or around the Manuʻa Islands, likely closer to Taʻū rather than Ofu-Olosega. Approximately 20 earthquakes per hour have been recorded for the past several days in the Manuʻa Islands. Estimated magnitudes of the largest earthquakes are between magnitude 2 and 3. The USGS will have more information about the source and cause of the earthquakes next week after expanding the monitoring network.

Volcanoes in the Manuʻa Islands are monitored with a limited real-time seismic network consisting of four microseismometers on Tutuila, Taʻū, and Ofu-Olosega Islands. HVO staff are working with the NOAA Pago Pago National Weather Service Office (NWS) to expand the American Samoa monitoring network. Satellite remote sensing is another tool being used, which may detect heat, volcanic gas, and volcanic ash associated with early phases of volcanic activity.

Current earthquake monitoring is based on the number and relative size of earthquakes and the estimated distance of earthquakes from the microseismometers. Due to the limitations of the current earthquake monitoring equipment, the exact location, depth, and magnitude of these earthquakes are unknown.

Samoan language alert level and color code definitions: https://www.usgs.gov/media/files/volcano-aviation-codes-and-alert-levels-english-and-samoan

An earthquake swarm is occurring in the Manuʻa Islands of American Samoa. As the federal entity responsible for monitoring earthquakes and volcanoes in American Samoa, the U.S. Geological Survey Hawaiian Volcano Observatory (HVO) is assigning the Taʻū Island and Ofu-Olosega Volcano Alert Levels to ADVISORY and Aviation Color Codes YELLOW. The designation previously was UNASSIGNED. This designation does not reflect a change in the behavior of either volcano; it simply acknowledges that the number, size, and frequency of earthquakes being felt by people on Taʻū Island and Ofu-Olosega are well above typical background activity (a NORMAL/GREEN alert level). The first reports of felt earthquakes occurred on July 26, 2022. Personal reports and instruments installed over the past week confirm the continuation of elevated earthquake activity.  

Data analysis from simple earthquake detection equipment installed on Tutuila, Taʻū, and Ofu-Olosega Islands indicate that the earthquakes are occurring beneath or around the Manuʻa Islands, likely closer to Taʻū rather than Ofu-Olosega. Approximately 20 earthquakes per hour have been recorded for the past several days in the Manuʻa Islands. Estimated magnitudes of the largest earthquakes are between magnitude 2 and 3. The USGS will have more information about the source and cause of the earthquakes next week after expanding the monitoring network. 

Volcanoes in the Manuʻa Islands are monitored with a limited real-time seismic network consisting of four microseismometers on Tutuila, Taʻū, and Ofu-Olosega Islands. HVO staff are working with the NOAA Pago Pago National Weather Service Office (NWS) to expand the American Samoa monitoring network. Satellite remote sensing is another tool being used, which may detect heat, volcanic gas, and volcanic ash associated with early phases of volcanic activity. 

Current earthquake monitoring is based on the number and relative size of earthquakes and the estimated distance of earthquakes from the microseismometers. Due to the limitations of the current earthquake monitoring equipment, the exact location, depth, and magnitude of these earthquakes are unknown.  

Samoan language alert level and color code definitions: https://www.usgs.gov/media/files/volcano-aviation-codes-and-alert-levels-english-and-samoan 

No ash emissions or explosive activity have been detected at Semisopochnoi since June 12. Seismic activity continues, but at low levels. Thus the Aviation Color Code and Volcano Alert Level are being lowered to YELLOW/ADVISORY.  

Steaming and sulfur dioxide emissions from the active north crater of Mount Cerberus continue.

Small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Cerberus and ash clouds usually under 10,000 ft (3 km) above sea level have characterized the recent activity and could begin again with little warning. 

Semisopochnoi is monitored by local seismic and infrasound sensors, satellite data, web cameras, and remote infrasound and lightning networks.