USGS Volcanoes: Notices released in the last day.

Slow eruption of lava within the summit crater continues. Minor earthquakes were detected over the past day, likely associated with rockfall on the growing dome. No activity was observed in cloudy satellite and webcam images over the past day.  

The current eruption began in July 2021. Since then, lava flows have filled most of the summit crater and advanced into valleys below. There have been no explosions at Great Sitkin Volcano since an event in May 2021. The volcano is monitored using local seismic and infrasound sensors, satellite data, webcams, and regional infrasound and lightning networks.

Low-level earthquake activity continued over the past day. No activity was observed in cloudy webcam images. Sulfur dioxide from the volcano was detected in satellite data yesterday. 

A new temporary monitoring station was installed recently near Mount Kupreanof and is providing seismic data, infrasound data, gas measurements, and web camera images on an intermittent basis. This is by design to conserve battery power, but the frequency of data acquisition can be increased if activity warrants. The closest functioning seismometers that provide continuous data are approximately 10 miles (16 km) to the northeast of the volcano as part of the Mount Veniaminof network. Mount Kupreanof is also monitored by satellite data, remote infrasound and lightning networks, and visual observations from pilots and mariners passing by the volcano.

Unrest continues with minor seismic and infrasound activity detected during the past day. Sulfur dioxide emissions were observed in satellite data yesterday. No activity was observed in cloudy webcam images. 

Local seismic and infrasound sensors, web cameras, and a geodetic network are used to monitor Shishaldin Volcano. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lightning data, and satellite images to detect eruptions. 

Slow eruption of lava within the summit crater continues. Minor earthquakes were detected over the past day, likely associated with rockfall on the growing dome. No activity was observed in cloudy satellite and webcam images over the past day.  

An AVO field team performed an aerial survey of the growing lava dome yesterday. 

The current eruption began in July 2021. Since then, lava flows have filled most of the summit crater and advanced into valleys below. There have been no explosions at Great Sitkin Volcano since an event in May 2021. The volcano is monitored using local seismic and infrasound sensors, satellite data, webcams, and regional infrasound and lightning networks.

Low-level earthquake activity continued over the past day. No activity was observed in cloudy satellite and webcam images. 

A new temporary monitoring station was installed recently near Mount Kupreanof and is providing seismic data, infrasound data, gas measurements, and web camera images on an intermittent basis. This is by design to conserve battery power, but the frequency of data acquisition can be increased if activity warrants. The closest functioning seismometers that provide continuous data are approximately 10 miles (16 km) to the northeast of the volcano as part of the Mount Veniaminof network. Mount Kupreanof is also monitored by satellite data, remote infrasound and lightning networks, and visual observations from pilots and mariners passing by the volcano.

Unrest continues with minor seismic and infrasound activity detected during the past day. Sulfur dioxide emissions were observed in satellite data. No activity was observed in cloudy satellite and webcam images. 

Local seismic and infrasound sensors, web cameras, and a geodetic network are used to monitor Shishaldin Volcano. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lightning data, and satellite images to detect eruptions. 

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

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

Past Week Observations for August 10 (0000h PDT) to August 16 (2359h PDT):

One earthquake greater than M1 was recorded near Mount Shasta, with a magnitude of M2.2.

Typical seismicity was recorded at The Geysers geothermal field south of the Clear Lake Volcanic Field; 96 earthquakes greater than M1 were recorded, with the largest having a magnitude of M3.2.

Five earthquakes greater than M1 were recorded in the Sierra Nevada Block, south of Mammoth Mountain and Long Valley, with the largest having a magnitude of M3.4.

Thirteen earthquakes greater than M1 were recorded in the Coso Volcanic Field, with the largest having a magnitude of M2.8.

Two earthquakes greater than M1 were recorded near the Salton Buttes, with the largest having a magnitude of M2.9.


 

Overview:

The summit eruption of Kīlauea in Halemaʻumaʻu is paused. Episode 53 ended on August 13. Data from summit tiltmeters showed re-inflation began immediately following the end of episode 53.  Preliminary data suggest that another episode is likely between Friday August 21 and Thursday August 27.

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

USGS HVO continues to experience sporadic outages due to power and possible storm damages.  Currently, a few of the fixed webcams and the UWD summit tiltmeter are offline.  Staff are working on these issues.  Most of the HVO monitoring network remains functional allowing monitoring of volcanic and seismic activity across the Hawaiian Islands.  

A summary of episode 53 that ended August 13 is posted below.

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

Summit Observations:

Weak to moderate glow from the north vent was observed on the streaming webcams for the first time since Hurricane Lala.  A few weak flashes of glow were also observed from the new west vent overnight, but the south vent remained dark.

Low-level seismic tremor has become continuous with only a few ragged tremor spikes. There was only one earthquake recorded in the summit area in the past 24 hours. 

The SMC tiltmeter has recorded a total of 12.1 microradians of inflationary tilt since the end of episode 53 and increased by 3 microradians in the last 24 hours. Deflationary tilt measured at the summit tiltmeter at Summer Camp (SMC) totaled 19.1 microradians during episode 53. The UWD tiltmeter is temporarily offline due to issues related to Hurricane Lala.

During inter-episode pauses, the sulfur dioxide (SO₂) emission rate from the summit typically varies between 1,000 to 5,000 tonnes per day. Winds are coming from the northeast between 11 to 20 miles per hour (mph), with gusts as high as 28 mph. Gas coming from the vents is being blown to the southwest. 

Rift Zone Observations:

Rates of seismicity and ground deformation remain low in the East Rift Zone and Southwest Rift Zone. SO₂ emissions from the East Rift Zone remain below the detection limit.

Analysis:

The abrupt switch from summit deflation to inflation at the end of episode 53 along with glow from the vents indicates that episode 54 fountaining is likely. There has already been one deflationary excursion on Saturday August 15, suggest the stepwise reinflation that preceded episodes 52 and 53 is likely to continue as we approach episode 54. The deflationary steps are not possible to forecast and interfere with the normal episode forecasts. Preliminary data suggest that another episode is likely between Friday August 21 and Thursday August 27.

Kīlauea has been erupting episodically since December 23, 2024, from two vents (north and south) in Halema‘uma‘u. A collapse pit in the slope behind the south vent formed a new west vent during episode 53. Lava fountaining episodes, which generally last for less than 12 hours, are separated by pauses of two or more weeks.

HVO continues to closely monitor Kīlauea and is in contact with Hawai‘i Volcanoes National Park and the Hawai‘i County Civil Defense Agency about eruptive hazards.

Please see the Hawaiʻi Volcanoes National Park website for visitor information: https://www.nps.gov/havo/index.htm

Summary of episode 53:

A detailed account of episode 53 is given in the HVO Status Report issued on August 13: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-08-13T11:52:10+00:00

• Episode 53 of the ongoing Halemaʻumaʻu eruption began around 3:45 p.m. HST on August 12 and ended abruptly at 1:23 a.m. HST on August 13, 2026.
• The maximum lava fountain height was approximately 500 feet (150 meters) above ground level from the north vent. The south vent never fountained during this episode but did produce overflows prior to the fountaining episode. A new west vent produced precursory overflows and emitted intermittent flames through most of the eruption. 
• The maximum plume height was approximately 18,000 (5,500 meters) above mean sea level. 

• Tephra fall was restricted mostly to the closed area of Hawaiʻi Volcanoes National Park, southwest of the active Halemaʻumaʻu vents.  

   

Resources:

NOTE: HVO’s monitoring network is mostly recovered from recent power- and storm-related outages. Several summit stations will remain offline as we continue working to repair instruments and re-establish connections in our monitoring network.

The following links provide more information about the current eruption that began on December 23, 2024:

• Eruption resources, including the most recent map and a timeline of eruption episodes since December 23, 2024: https://www.usgs.gov/volcanoes/kilauea/science/eruption-information
• Short messages tracking the evolution of the lava fountains and eruptive activity can be found here: https://www.usgs.gov/observatories/hvo/observatory-messages
• Three Kīlauea summit livestream cameras that show eruptive lava fountains are available here: https://www.youtube.com/@usgs/streams
• Summit eruption webcams: https://www.usgs.gov/volcanoes/kilauea/summit-webcams
• Volcano Watch article on gas pistons: https://www.usgs.gov/observatories/hvo/news/volcano-watch-so-what-earth-or-least-kilauea-a-gas-piston

Hazards:

This episodic eruption is occurring within a closed area of Hawai'i Volcanoes National Park.

• Volcanic Gas: high levels of volcanic gas—primarily water vapor (H₂O), carbon dioxide (CO₂), and sulfur dioxide (SO₂)—are continually released during an eruption. Emissions can remain locally hazardous in the areas immediately downwind of the vents, even when the vents are not actively erupting. SO₂ reacts in the atmosphere to create vog (volcanic air pollution) downwind. SO₂ and vog may cause respiratory and other problems at high concentrations. Further information on vog can be found at https://vog.ivhhn.org/
• Tephra: small glassy volcanic fragments—volcanic ash, pumice, scoria, Pele’s hair and reticulite—are created by the lava fountains. A combination of fountaining dynamics and wind conditions determines where tephra fall may occur for any given eruption episode. Larger particles fall near the vents while light particles may be wafted greater distances. These particles may be remobilized during windy conditions following recent eruptive episodes. Residents and visitors should minimize exposure to these fragments, which can cause skin, eye, and respiratory irritation. More information and guidance on tephra fall hazards is available at https://seagrant.soest.hawaii.edu/resource-and-guidance-for-volcanic-tephra-fall/
• Lava flows: lava on the floor of Halemaʻumaʻu crater and the southwest side of Kaluapele, Kīlauea's summit caldera, remains hot and may slowly move in the days immediately following an eruptive episode.

Other significant hazards exist around Kīlauea caldera from Halemaʻumaʻu crater wall instability, ground cracking, and rockfalls that can be enhanced by earthquakes. Close to the eruptive vents, the tephra material on the crater rim is prone to cracking, slumping, and small landslides that sometimes expose hot and molten material within. This underscores the extremely hazardous nature of Kīlauea's caldera rim surrounding Halemaʻumaʻu crater, an area that has been closed to the public since late 2007.

HAWAIIAN VOLCANO OBSERVATORY INFORMATION STATEMENT

On Monday, August 17, 9:24 a.m. HST, a magnitude-4.1 earthquake occurred 10 mi (16 km) south-southeast of Hōnaunau-Nāpōʻopoʻo on the Island of Hawaiʻi at a depth of 14 mi (23 km) below sea level. This event is likely an aftershock of the magnitude-6.0 that occurred on May 23, 2026. The earthquake had no apparent impact on either Mauna Loa or Kīlauea volcanoes.

The USGS Hawaiian Volcano Observatory continues to monitor Hawaiian volcanoes for any changes.

EARTHQUAKE DESCRIPTION

·       Magnitude: 4.1

·       Date and Time: August 17, 2026, at 9:24 a.m. HST

·       Location: 10 mi (16 km) SSE of Hōnaunau-Nāpōʻopoʻo

·       Depth: 14 mi (23 km) below sea level

·       Aftershocks are possible in the coming days to weeks

EARTHQUAKE INTENSITY AND AFFECTED AREA

·       Potential Damage: No damage to buildings or infrastructure expected based on earthquake intensity

·       Maximum Intensity, Modified Mercalli Scale (https://www.usgs.gov/natural-hazards/earthquake-hazards/science/modified-mercalli-intensity-scale)

·       Community-reported: IV - light shaking

·       Instrument-derived: IV - light shaking

·       Felt Reports: More than 93 within the first hour (http://earthquake.usgs.gov/dyfi/)

·       Felt Area: Mostly across the west of Island of Hawaiʻi with a few reports from Maui and O‘ahu

·       Visit NOAA’s Tsunami Warning Center website for updated information: https://www.tsunami.gov/

EARTHQUAKE MAPS AND ADDITIONAL INFORMATION

·       USGS National Earthquake Information Center Maps and Reports for this Event: https://earthquake.usgs.gov/earthquakes/eventpage/hv75019812

·       USGS-HVO Interactive Earthquake Map of Hawaiʻi: https://www.usgs.gov/observatories/hawaiian-volcano-observatory/earthquakes

Overview:

The summit eruption of Kīlauea in Halemaʻumaʻu is paused. Episode 53 ended on August 13. Data from summit tiltmeters showed re-inflation began immediately following the end of episode 53.  Preliminary data suggest that another episode is likely between Friday August 21 and Thursday August 27.

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

USGS HVO experienced a data outage from about 3:30 a.m. to just before 9:00 a.m. HST this morning due to ongoing telecommunications issues related to Hurricane Lala.  All datastreams have been restored.

A summary of episode 53 that ended August 13 is posted below.

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

Summit Observations:

Heavy rain and clouds at the summit continue to obscure views from HVO webcams over the past 24 hours.

Low-level seismic tremor with periodic seismic pulsing continues, typical of inter-episode pauses. There was only one earthquake recorded in the summit area in the past 24 hours. 

The UWD tiltmeter has recorded a total of 7.4 microradians of inflationary tilt since the end of episode 53. Rapid inflation following the end of episode 53 changed to mild deflation in the early morning hours of August 14; mild deflationary tilt continued through Sunday morning when inflationary tilt resumed and increased by 2.6 microradians in the last 24 hours. Deflationary tilt measured at the summit tiltmeter at Uēkahuna (UWD) totaled 14.0 microradians during episode 53.

During inter-episode pauses, the sulfur dioxide (SO₂) emission rate from the summit typically varies between 1,000 to 5,000 tonnes per day. 

Rift Zone Observations:

Rates of seismicity and ground deformation remain low in the East Rift Zone and Southwest Rift Zone. SO₂ emissions from the East Rift Zone remain below the detection limit.

Analysis:

The abrupt switch from summit deflation to inflation at the end of episode 53 along with glow from the vents indicates that episode 54 fountaining is likely. There has already been one deflationary excursion on Saturday August 15, suggest the step-wise reinflation that preceded episodes 52 and 53 is likely to continue as we approach episode 54. The deflationary steps are not possible to forecast and interfere with the normal episode forecasts. Preliminary data suggest that another episode is likely between Friday August 21 and Thursday August 27.

Kīlauea has been erupting episodically since December 23, 2024, from two vents (north and south) in Halema‘uma‘u. A collapse pit in the slope behind the south vent formed a new west vent during episode 53. Lava fountaining episodes, which generally last for less than 12 hours, are separated by pauses of two or more weeks.

HVO continues to closely monitor Kīlauea and is in contact with Hawai‘i Volcanoes National Park and the Hawai‘i County Civil Defense Agency about eruptive hazards.

Please see the Hawaiʻi Volcanoes National Park website for visitor information: https://www.nps.gov/havo/index.htm

Summary of episode 53:

A detailed account of episode 53 is given in the HVO Status Report issued on August 13: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-08-13T11:52:10+00:00

• Episode 53 of the ongoing Halemaʻumaʻu eruption began around 3:45 p.m. HST on August 12 and ended abruptly at 1:23 a.m. HST on August 13, 2026.
• The maximum lava fountain height was approximately 500 feet (150 meters) above ground level from the north vent. The south vent never fountained during this episode but did produce overflows prior to the fountaining episode. A new west vent produced precursory overflows and emitted intermittent flames through most of the eruption. 
• The maximum plume height was approximately 18,000 (5,500 meters) above mean sea level. 

• Tephra fall was restricted mostly to the closed area of Hawaiʻi Volcanoes National Park, southwest of the active Halemaʻumaʻu vents.  

   

Resources:

NOTE: HVO’s monitoring network is mostly recovered from recent power- and storm-related outages. Several summit stations will remain offline as we continue working to repair instruments and re-establish connections in our monitoring network.

The following links provide more information about the current eruption that began on December 23, 2024:

• Eruption resources, including the most recent map and a timeline of eruption episodes since December 23, 2024: https://www.usgs.gov/volcanoes/kilauea/science/eruption-information
• Short messages tracking the evolution of the lava fountains and eruptive activity can be found here: https://www.usgs.gov/observatories/hvo/observatory-messages
• Three Kīlauea summit livestream cameras that show eruptive lava fountains are available here: https://www.youtube.com/@usgs/streams
• Summit eruption webcams: https://www.usgs.gov/volcanoes/kilauea/summit-webcams
• Volcano Watch article on gas pistons: https://www.usgs.gov/observatories/hvo/news/volcano-watch-so-what-earth-or-least-kilauea-a-gas-piston

Hazards:

This episodic eruption is occurring within a closed area of Hawai'i Volcanoes National Park.

• Volcanic Gas: high levels of volcanic gas—primarily water vapor (H₂O), carbon dioxide (CO₂), and sulfur dioxide (SO₂)—are continually released during an eruption. Emissions can remain locally hazardous in the areas immediately downwind of the vents, even when the vents are not actively erupting. SO₂ reacts in the atmosphere to create vog (volcanic air pollution) downwind. SO₂ and vog may cause respiratory and other problems at high concentrations. Further information on vog can be found at https://vog.ivhhn.org/
• Tephra: small glassy volcanic fragments—volcanic ash, pumice, scoria, Pele’s hair and reticulite—are created by the lava fountains. A combination of fountaining dynamics and wind conditions determines where tephra fall may occur for any given eruption episode. Larger particles fall near the vents while light particles may be wafted greater distances. These particles may be remobilized during windy conditions following recent eruptive episodes. Residents and visitors should minimize exposure to these fragments, which can cause skin, eye, and respiratory irritation. More information and guidance on tephra fall hazards is available at https://seagrant.soest.hawaii.edu/resource-and-guidance-for-volcanic-tephra-fall/
• Lava flows: lava on the floor of Halemaʻumaʻu crater and the southwest side of Kaluapele, Kīlauea's summit caldera, remains hot and may slowly move in the days immediately following an eruptive episode.

Other significant hazards exist around Kīlauea caldera from Halemaʻumaʻu crater wall instability, ground cracking, and rockfalls that can be enhanced by earthquakes. Close to the eruptive vents, the tephra material on the crater rim is prone to cracking, slumping, and small landslides that sometimes expose hot and molten material within. This underscores the extremely hazardous nature of Kīlauea's caldera rim surrounding Halemaʻumaʻu crater, an area that has been closed to the public since late 2007.