ALASKA VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Wednesday, August 12, 2026, 1:25 PM AKDT (Wednesday, August 12, 2026, 21:25 UTC)
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.
To view monitoring data and other information about Great Sitkin Volcano: https://avo.alaska.edu/volcano/great-sitkin
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.
To view monitoring data and other information about Mount Kupreanof: https://avo.alaska.edu/volcano/kupreanof
Unrest continues with minor seismic and infrasound activity detected during the past day. No activity was observed in cloudy satellite and webcam images. Sulfur dioxide emissions were observed in satellite data.
Local seismic and infrasound sensors, web cameras, and a geodetic network are used to monitor Shishaldin Volcano. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lightning data, and satellite images to detect eruptions.
To view monitoring data and other information about Shishaldin Volcano: https://avo.alaska.edu/volcano/shishaldin
Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497
David Fee, Coordinating Scientist, UAFGI, dfee1@alaska.edu (907) 378-5460
Contact AVO: https://avo.alaska.edu/contact
The Alaska Volcano Observatory is a cooperative program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys.
Episode 53 of lava fountaining in Halemaʻumaʻu at the summit of Kīlauea began at 3:45 p.m. HST on August 12 and continues as of this notice at 15:45 p.m. HST.
Peak fountain heights have reached 500 ft (150 m) above ground level between 5:00 and 5:45 p.m. HST. The plume from this eruption is reaching over 18,000 feet above sea level. Ground-level sensors near the eruptive vents indicate that winds are blowing from the northeast carrying SO2 gas along with fine ash and Peleʻs hair to the southwest. Models, NWS data, and satellite images show the plume carrying gas and possibly fine ash and Peleʻs hair westward from the vent area.
Most lava fountaining episodes since December 23, 2024, have continued for a day or less.
Hazard Analysis:
Volcanic Gas: water vapor (H2O), carbon dioxide (CO2), and sulfur dioxide (SO2) are continuously released during an eruption. SO2 reacts in the atmosphere to create the visible haze known as vog (volcanic air pollution) downwind, which may cause respiratory and other problems. Further information on vog can be found at https://vog.ivhhn.org/
Tephra: small glassy volcanic fragments—volcanic ash, pumice, scoria, Pele’s hair and reticulite—are created by the lava fountains. A combination of fountaining dynamics and wind conditions determines where tephra fall may occur for any given eruption episode. Larger particles fall near the vents while light particles may be wafted greater distances. These particles may be remobilized during windy conditions following recent eruptive episodes. Residents and visitors should minimize exposure to these fragments, which can cause skin, eye, and respiratory irritation. More information and guidance on tephra fall hazards is available at https://seagrant.soest.hawaii.edu/resource-and-guidance-for-volcanic-tephra-fall/
Lava flows: generally advance slowly downslope, and during this eruption flows have been confined to Halemaʻumaʻu crater and the southwest side of Kaluapele, Kīlauea's summit caldera.
Other significant hazards exist around Kīlauea caldera from Halemaʻumaʻu crater wall instability, ground cracking, and rockfalls that can be enhanced by earthquakes. Close to the vents, the tephra material on the crater rim is prone to cracking, slumping, and small landslides that sometimes expose hot and molten material within. This underscores the extremely hazardous nature of Kīlauea's caldera rim surrounding Halemaʻumaʻu crater, an area that has been closed to the public since late 2007.
HVO continues to closely monitor Kīlauea and will issue additional notices as needed based on activity. Regularly scheduled daily updates for Kīlauea are posted on the HVO website at https://www.usgs.gov/volcanoes/kilauea/volcano-updates
More Information:
Subscribe to these messages: https://volcanoes.usgs.gov/vns2/
Summary of volcanic hazards from eruptions: https://www.usgs.gov/observatories/hvo/hazards
Recent earthquakes in Hawaiʻi (map and list): https://www.usgs.gov/observatories/hvo
Explanation of Volcano Alert Levels and Aviation Color Codes: https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes
WMPA01 PHVO 130345
VONA
DTG: 20260813/0345Z
VOLCANO: KILAUEA 332010
PSN: N1925 W15517
AREA: HAWAII
SOURCE ELEV: 4091FT AMSL
NOTICE NR: 2026/55
CURRENT COLOUR CODE: ORANGE
PREVIOUS COLOUR CODE: ORANGE
SVO: HAWAIIAN VOLCANO OBSERVATORY
ACT STS: ERUPTION ONGOING
ONSET: UNKNOWN
DUR: ONGOING CONS
VA CLD HGT: UNKNOWN
HGT SOURCE: WEBCAM
MOV: SW
CTC: HVO DUTY SCIENTIST: 808-785-3144
RMK: LAVA FOUNTAIN EPISODE 53 CONTINUES AT KILAUEA SUMMIT. FOUNTAINS CURRENTLY REACHING
500 FT AGL. VOLCANIC PLUME CURRENTLY REACHING 18000 FT AMSL. LIMITED FALLOUT LIKELY
IN THE WSW DIRECTION DOWNWIND OF VENTS.
NXT NOTICE: A NEW VONA WILL BE ISSUED IF COND CHANGE SIGNIFICANTLY OR IF THE COLOR CODE CHANGES
NNNNEpisode 53 of lava fountaining in Halemaʻumaʻu at the summit of Kīlauea began from the north vent at 3:45 p.m. HST on August 12, 2026. Fountaining is currently 80-100 ft (25-30 meters) high and expected to reach a maximum height in 1-2 hours.
Fountain activity transitioned gradually from precursory lava flows from the north vent. Small glimpses of spatter were seen after 10:00 a.m. HST but spatter was not consistently visible until 11:04 a.m. HST. This was followed by a series of short-lived lava overflows that began at 11:20 a.m., 11:35 a.m., 11:45 a.m., and 12:23 p.m. HST, each lasting 1-4 minutes. A fifth sluggish flow began around 1:00 p.m. HST and became sustained, gradually growing for about 45 minutes. At 1:45 p.m. HST, there was a dramatic increase in output correlated with a switch to deflationary tilt. A double dome fountain formed and began feeding a broad overflow that rapidly extended more than 2000 feet (600 meters) from the vent. Large overflows from the south vent began at 3:26 p.m. and 3:38 p.m. HST and lasted approximately 5-6 minute each. A small flow was also visible from the collapse crater behind the south vent beginning at 3:31 p.m. HST.
Ground-level sensors near the eruptive vents indicate that winds are blowing from the northeast direction, which suggests that volcanic gas emissions and volcanic material may be distributed to the southwest direction from Halemaʻumaʻu. Winds above the inversion layer are more easterly and expected to carry tephra westward, if the fountains are high enough. The volcanic gas plume is currently 6,000 ft above ground level.
Most lava fountaining episodes since December 23, 2024, have continued for a day or less.
Hazard Analysis:
Volcanic Gas: water vapor (H2O), carbon dioxide (CO2), and sulfur dioxide (SO2) are continuously released during an eruption. SO2 reacts in the atmosphere to create the visible haze known as vog (volcanic air pollution) downwind, which may cause respiratory and other problems. Further information on vog can be found at https://vog.ivhhn.org/
Tephra: small glassy volcanic fragments—volcanic ash, pumice, scoria, Pele’s hair and reticulite—are created by the lava fountains. A combination of fountaining dynamics and wind conditions determines where tephra fall may occur for any given eruption episode. Larger particles fall near the vents while light particles may be wafted greater distances. These particles may be remobilized during windy conditions following recent eruptive episodes. Residents and visitors should minimize exposure to these fragments, which can cause skin, eye, and respiratory irritation. More information and guidance on tephra fall hazards is available at https://seagrant.soest.hawaii.edu/resource-and-guidance-for-volcanic-tephra-fall/
Lava flows: ggenerally advance slowly downslope, and during this eruption flows have been confined to Halemaʻumaʻu crater and the southwest side of Kaluapele, Kīlauea's summit caldera.
Other significant hazards exist around Kīlauea caldera from Halemaʻumaʻu crater wall instability, ground cracking, and rockfalls that can be enhanced by earthquakes. Close to the vents, the tephra material on the crater rim is prone to cracking, slumping, and small landslides that sometimes expose hot and molten material within. This underscores the extremely hazardous nature of Kīlauea's caldera rim surrounding Halemaʻumaʻu crater, an area that has been closed to the public since late 2007.
HVO continues to closely monitor Kīlauea and will issue additional notices as needed based on activity. Regularly scheduled daily updates for Kīlauea are posted on the HVO website at https://www.usgs.gov/volcanoes/kilauea/volcano-updates
More Information:
Subscribe to these messages: https://volcanoes.usgs.gov/vns2/
Summary of volcanic hazards from eruptions: https://www.usgs.gov/observatories/hvo/hazards
Recent earthquakes in Hawaiʻi (map and list): https://www.usgs.gov/observatories/hvo
Explanation of Volcano Alert Levels and Aviation Color Codes: https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes
WMPA01 PHVO 130153
VONA
DTG: 20260813/0153Z
VOLCANO: KILAUEA 332010
PSN: N1925 W15517
AREA: HAWAII
SOURCE ELEV: 4091FT AMSL
NOTICE NR: 2026/54
CURRENT COLOUR CODE: ORANGE
PREVIOUS COLOUR CODE: ORANGE
SVO: HAWAIIAN VOLCANO OBSERVATORY
ACT STS: ERUPTION ONGOING
ONSET: 20260813/0145Z
DUR: ONGOING EPISODIC
VA CLD HGT: UNKNOWN
HGT SOURCE: WEBCAM
MOV: UNKNOWN
CTC: HVO DUTY SCIENTIST: 808-785-3144
RMK: LAVA FOUNTAIN EPISODE 53 STARTED AT KILAUEA SUMMIT. CURRENT FOUNTAIN HEIGHTS 80-100
FT AGL. PEAK FOUNTAINING OCCURS 1-2 HOURS AFTER ONSET AND TYPICALLY REACHES 500-1500
FT AGL WITH PLUMES UP TO 10,000-25,000 FT AMSL. DOWNWIND TEPHRA FALLOUT IS POSSIBLE.
NXT NOTICE: A NEW VONA WILL BE ISSUED IF COND CHANGE SIGNIFICANTLY OR IF THE COLOR CODE CHANGES
NNNNPrecursory low-level activity for episode 53 of the ongoing Halemaʻumaʻu eruption at the summit of Kīlauea began around 11:20 a.m. HST on August 12, 2026, with the onset of intermittent lava dome fountaining and overflows from the north vent. A second overflow began at 11:35 and lasted roughly 4 minutes. Summit inflation is continuing. Accordingly, HVO is raising the Alert Level for Kīlauea from ADVISORY to WATCH and the Aviation Color Code from YELLOW to ORANGE. Alert level and aviation color code definitions: https://www.usgs.gov/programs/VHP/alert-level-system. This low-level precursory activity can continue for hours to days before the lava fountaining episode beings. The forecast for episode 53 of lava fountaining to start is between today and tomorrow, August 13. Another VAN will be published when lava fountaining episode 53 begins.
Most lava fountaining episodes since December 23, 2024, have continued for a day or less.
Hazard Analysis:
Volcanic Gas: water vapor (H2O), carbon dioxide (CO2), and sulfur dioxide (SO2) are continuously released during an eruption. SO2 reacts in the atmosphere to create the visible haze known as vog (volcanic air pollution) downwind, which may cause respiratory and other problems. Further information on vog can be found at https://vog.ivhhn.org/.
Tephra: small glassy volcanic fragments—volcanic ash, pumice, scoria, Pele’s hair and reticulite—are created by the lava fountains. A combination of fountaining dynamics and wind conditions determines where tephra fall may occur for any given eruption episode. Larger particles fall near the vents while light particles may be wafted greater distances. These particles may be remobilized during windy conditions following recent eruptive episodes. Residents and visitors should minimize exposure to these fragments, which can cause skin, eye, and respiratory irritation. More information and guidance on tephra fall hazards is available at https://seagrant.soest.hawaii.edu/resource-and-guidance-for-volcanic-tephra-fall/.
Lava flows: generally advance slowly downslope, and during this eruption flows have been confined to Halemaʻumaʻu crater and the southwest side of Kaluapele, Kīlauea's summit caldera.
Other significant hazards exist around Kīlauea caldera from Halemaʻumaʻu crater wall instability, ground cracking, and rockfalls that can be enhanced by earthquakes. Close to the vents, the tephra material on the crater rim is prone to cracking, slumping, and small landslides that sometimes expose hot and molten material within. This underscores the extremely hazardous nature of Kīlauea's caldera rim surrounding Halemaʻumaʻu crater, an area that has been closed to the public since late 2007.
HVO continues to closely monitor Kīlauea and will issue additional notices as needed based on activity. Regularly scheduled daily updates for Kīlauea are posted on the HVO website at https://www.usgs.gov/volcanoes/kilauea/volcano-updates
More Information:
Subscribe to these messages: https://volcanoes.usgs.gov/vns2/
Summary of volcanic hazards from eruptions: https://www.usgs.gov/observatories/hvo/hazards
Recent earthquakes in Hawaiʻi (map and list): https://www.usgs.gov/observatories/hvo
Explanation of Volcano Alert Levels and Aviation Color Codes: https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes
WMPA01 PHVO 122146
VONA
DTG: 20260812/2146Z
VOLCANO: KILAUEA 332010
PSN: N1925 W15517
AREA: HAWAII
SOURCE ELEV: 4091FT AMSL
NOTICE NR: 2026/53
CURRENT COLOUR CODE: ORANGE
PREVIOUS COLOUR CODE: YELLOW
SVO: HAWAIIAN VOLCANO OBSERVATORY
ACT STS: ERUPTION ONGOING
ONSET: UNKNOWN
DUR: ONGOING EPISODIC
VA CLD HGT: NO VA CLD PRODUCED
HGT SOURCE: NO VA CLD PRODUCED
MOV: NO VA CLD PRODUCED
CTC: HVO DUTY SCIENTIST: 808-785-3144
RMK: LOW-LEVEL ERUPTION OF LAVA BEGAN AT THE SUMMIT OF KILAUEA AT 11:20 AM ON AUGUST 12,
2026. LOW-LEVEL ACTIVITY CAN PERSIST FOR HOURS TO DAYS BEFORE THE LAVA FOUNTAIN
EPISODE BEGINS. LAVA FOUNTAIN EPISODE 53 IS FORECAST TO START TODAY OR TOMRROW.
NXT NOTICE: A NEW VONA WILL BE ISSUED IF COND CHANGE SIGNIFICANTLY OR IF THE COLOR CODE CHANGES
NNNN
HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Wednesday, August 12, 2026, 9:58 AM HST (Wednesday, August 12, 2026, 19:58 UTC)
Overview:
The summit eruption of Kīlauea in Halemaʻumaʻu remains paused. Glow strengthened overnight at the north vent and new collapse. Strong gas pistoning began at 4 a.m. HST with large flames from the new collapse accompanying tremor peaks. Weak glow also returned to the south vent around 4:30 a.m. HST. Rapid inflation began yesterday morning, and 3.9 microradians of inflationary tilt were recorded by the Uēkahuna (UWD) tiltmeter in the past 20 hours. However, inflation rates have slowed this morning beginning around 6:00 a.m. HST. Inflation-based models forecast the start of episode 53 fountains sometime later today, August 12, through Friday, August 13, depending on inflation rates.
No significant activity has been noted along Kīlauea’s East Rift Zone or Southwest Rift Zone in the past day.
A summary of episode 52 is posted below.
NOTE: Significant changes in activity between Daily Updates are posted here: https://www.usgs.gov/observatories/hvo/observatory-messages
Summit Observations:
In the early evening, continuous weak to moderate glow was observed from the north vent, while the south vent remained dark. Around 8:45 p.m. HST, weak glow began to be visible from the new collapse (formerly called the new crack or fissure until overflight photos yesterday showed it to be a collapse). Glow strengthened to moderate from both north vent and the new collapse just before 10 p.m. HST, but the south vent remained dark. In the early morning hours, glow gradually brightened, becoming brightest with the return of tremor bursts associated with gas pistoning at 4:00 a.m. HST. In addition to bright glow, large flames were observed every 5-10 minutes from the collapse, correlating with tremor bursts. Moderate glow also returned to the south vent during these events.
Low-moderate tremor continued overnight with the addition of periodic tremor bursts beginning at 4:00 a.m. HST. The tremor bursts were associated with strong glow and flames from the new collapse and the return of glow to the south vent, all of which suggest a return to gas pistoning behavior. One very small (less than M1.0) earthquake was detected near the center of Halemaʻumaʻu crater over the past 24 hours.
The Uēkahuna (UWD) tiltmeter recorded the onset of rapid inflation beginning at 10:30 a.m. HST yesterday, gaining 3.9 microradians of tilt overnight before slowing down around 6 a.m. HST this morning. The UWD tilt meter has regained 13.9 microradians of the 14.4 microradians of deflationary tilt lost during episode 52. An offset in tiltmeter data at 5:48 pm yesterday is due to a M5.2 earthquake occurred near Kamaʻehuakanaloa.
During inter-episode pauses, sulfur dioxide (SO₂) emission rates typically vary between 1,000–5,000 tonnes per day. Winds are currently from the northeast and are expected to remain that way until sometime Friday when weather may be influenced by the approaching tropical disturbance.
Rift Zone Observations:
Rates of seismicity and ground deformation remain low in the East Rift Zone. SO2 emissions from the East Rift Zone remain below the detection limit.
Seismicity has returned to normal background in the Southwest Rift Zone after a swarm of 18 small earthquakes were recorded Monday morning between 4:00 - 6:20 a.m. HST.
Analysis:
The abrupt switch from summit deflation to inflation at the end of episode 52, along with continued glow from the vents, indicates that episode 53 fountaining is likely. Inflationary tilt since the end of episode 52 was interrupted by deflation from August 2 to 3. A second deflationary step began at 6:00 a.m. HST Friday and continued through Tuesday at 10:30 a.m. HST when rapid inflation began. The rapid inflation gained nearly 4 microradians in the past 22 hours regaining most of what was lost during the episode 52 fountain event. However, inflation slowed at about 6 a.m. HST and is continuing at a very slow rate. Small steps of slow to no inflation preceded the onset of episodes 51 and 52 fountains. The combination of prior deflations and tilt-based models have been used to forecast the onset of episode 53 fountaining between later today, August 12 through Friday, August 14. The forecast window may be adjusted if summit tilt rates continue to change.
Kīlauea has been erupting episodically since December 23, 2024, from two vents (north and south) in Halema‘uma‘u. Lava fountaining episodes, which generally last for less than 12 hours, are separated by pauses that can be longer than three weeks.
HVO continues to closely monitor Kīlauea and is in contact with Hawai‘i Volcanoes National Park and the Hawai‘i County Civil Defense Agency about eruptive hazards.
Please see the Hawaiʻi Volcanoes National Park website for visitor information: https://www.nps.gov/havo/index.htm
Summary of episode 52:
A detailed account of episode 52 is given in the HVO Status Report issued on July 29: https://volcanoes.usgs.gov/hans-public/notice/DOI-USGS-HVO-2026-07-29T13:10:51+00:00
Tephra fall was restricted mostly to the closed area of Hawaiʻi Volcanoes National Park to the 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, including the SDH tiltmeter, will remain offline until we are able to re-establish access across the deep tephra field southwest of the caldera.
The following links provide more information about the current eruption that began on December 23, 2024:
Hazards:
This episodic eruption is occurring within a closed area of Hawai'i Volcanoes National Park.
Other significant hazards exist around Kīlauea caldera from Halemaʻumaʻu crater wall instability, ground cracking, and rockfalls that can be enhanced by earthquakes. Close to the eruptive vents, the tephra material on the crater rim is prone to cracking, slumping, and small landslides that sometimes expose hot and molten material within. This underscores the extremely hazardous nature of Kīlauea's caldera rim surrounding Halemaʻumaʻu crater, an area that has been closed to the public since late 2007.
More Information:
The Hawaiian Volcano Observatory is one of five volcano observatories within the U.S. Geological Survey and is responsible for monitoring volcanoes and earthquakes in Hawaiʻi and American Samoa.
Subscribe to these messages: https://volcanoes.usgs.gov/vns2/
Summary of volcanic hazards from eruptions: https://www.usgs.gov/observatories/hvo/hazards
Recent earthquakes in Hawaiʻi (map and list): https://www.usgs.gov/observatories/hvo
Explanation of Volcano Alert Levels and Aviation Color Codes: https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes
HAWAIIAN VOLCANO OBSERVATORY INFORMATION STATEMENT
U.S. Geological Survey
Tuesday, August 11, 2026, 6:42 PM HST (Wednesday, August 12, 2026, 04:42 UTC)
HAWAIIAN VOLCANO OBSERVATORY INFORMATION STATEMENT
On Tuesday, August 11, 5:48 p.m. HST, a magnitude-5.2 earthquake occurred beneath Kamaʻehuakanaloa volcano 26 mi (42 km) east-southeast offshore of Nāʻālehu on the Island of Hawaiʻi at a depth of 7 mi (11 km) below sea level.
The magnitude-5.2 earthquake is part of an ongoing sequence of earthquakes associated with unrest of Kamaʻehuakanaloa (formerly Lōʻihi) Seamount that started on Sunday, August 9. These earthquakes have 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
EARTHQUAKE INTENSITY AND AFFECTED AREA
EARTHQUAKE MAPS AND ADDITIONAL INFORMATION
Background: Intermittent earthquake activity has been recorded in the vicinity of Kama‘ehuakanaloa (Lō‘ihi) since as early as 1952. The most energetic earthquake sequence occurred in July-August 1996, which included more than 4,000 earthquakes, with nearly 300 events larger than M3.0 and 95 events in the M4.0 to 4.9 range. More recently, a swarm of 100 earthquakes occurred on May 11, 2020, with 18 events in the M3.0 to 3.9 range. There are no working monitoring instruments on Kama‘ehuakanaloa volcano, whose peak is about 1,000 m (3,280 ft) below sea level. All real-time information about the volcano is derived from land-based seismometers on the Island of Hawai‘i.
More Information:
Kama‘ehuakanaloa website: https://www.usgs.gov/volcanoes/kama‘ehuakanaloa
The Hawaiian Volcano Observatory is one of five volcano observatories within the U.S. Geological Survey and is responsible for monitoring volcanoes and earthquakes in Hawaiʻi and American Samoa.
Subscribe to these messages: https://volcanoes.usgs.gov/vns2/
Summary of volcanic hazards from eruptions: https://www.usgs.gov/observatories/hvo/hazards
Recent earthquakes in Hawaiʻi (map and list): https://www.usgs.gov/observatories/hvo
Explanation of Volcano Alert Levels and Aviation Color Codes: https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes
