USGS HVO Volcanic Activity Notice — Eruption at Kīlauea Volcano summit continues

HVO/USGS Volcanic Activity Notice 

Volcanic Activity Summary: 

Kīlauea Volcano is erupting. At 9:30 p.m. HST on December 20, the USGS Hawaiian Volcano Observatory (HVO) detected glow within Halemaʻumaʻu crater at the summit of Kīlauea Volcano, indicating that an eruption had commenced within Kīlauea’s summit caldera. Due to the presence of the water lake at the summit of Kīlauea and the potential for steam-driven explosions and related hazards, HVO elevated Kīlauea’s volcano alert level to WARNING and its aviation color code to RED on December 20 as the progression of events was uncertain.

The water lake at the summit of Kīlauea has boiled away and an effusive eruption has commenced, with three vents in the wall of Halemaʻumaʻu crater generating lava flows that are contributing to a growing lava lake at the base of Halemaʻumaʻu crater. The eruption is currently confined to Halemaʻumaʻu crater.

HVO has decreased Kīlauea’s volcano alert level to WATCH and its aviation color code to ORANGE, reflecting the less-hazardous nature of the ongoing eruption.

Alert levels and aviation color codes are explained here: https://www.usgs.gov/natural-hazards/volcano-hazards/about-alert-levels

HVO continues to monitor the volcano closely and will report any significant changes.

Stay informed about Kīlauea by following volcano updates and tracking current monitoring data on the HVO web page (https://www.usgs.gov/volcanoes/kilauea/volcano-updates) or by signing up to receive updates by email at this site: https://volcanoes.usgs.gov/vns2/.

HVO is in constant communication with Hawai‘i Volcanoes National Park as this situation evolves. The eruption is currently taking place entirely within the park.

HVO is in constant communication with the County of Hawai‘i Civil Defense Agency.

Recent Observations:

An earthquake swarm beneath Kīlauea summit began around 8:30 p.m. HST on the evening of December 20, accompanied by ground deformation detected by tiltmeters. A bright glow and vigorous steam plume, generated by the boiling water lake in Halemaʻumaʻu, was subsequently observed on HVO webcams beginning approximately 9:30 p.m. HST. HVO scientists responded immediately and visually confirmed from the field that lava was visible within Halemaʻumaʻu. The steam plume dissipated shortly thereafter. Activity over the past ten hours has been characterized by three fissure vents on the north and northwest walls of Halemaʻumaʻu crater. Fountaining lava at these vents is estimated to be up to 25 m (82 ft) high; the vents are feeding lava flows into the base of Halemaʻumaʻu crater, which is being filled with a growing lava lake.

The lava lake has been rising approximately several meters (yards) an hour since the eruption began. The current lava lake exhibits a circulating perimeter, but stagnant center.

The event has been accompanied by only moderate amounts of deformation, indicating deflation of a magma reservoir under Halema’uma’u. Rates of tilting have decreased slightly since the beginning of the eruption.

Increased rates of seismicity in the summit region continue. Some of these earthquakes may be felt. A magnitude-4.4 earthquake located beneath Kīlauea Volcano's south flank occurred on Sunday, December 20, at 10:36 p.m. HST.

Visitors to the Hawai'i Volcanoes National Park should note that under southerly (non-trade) wind conditions, rockfalls and explosions can result in a dusting of powdery to gritty ash composed of volcanic glass and rock fragments. These ashfalls represent a minor hazard, but visitors should be aware that dustings of ash at areas around the Kīlauea summit are possible.

For more information on gas hazards at the summit of Kīlauea, please see: https://pubs.er.usgs.gov/publication/fs20173017

For more information about volcanic ash hazards and precautions at Kīlauea, please see: http://hvo.wr.usgs.gov/hazards/FAQ_SO2-Vog-Ash/main.html

For discussion of Kīlauea hazards, please see:

https://www.usgs.gov/observatories/hawaiian-volcano-observatory/hazards

Background:


Kīlauea Volcano had maintained a low level of non-eruptive unrest since the end of the 2018 lower East Rift Zone eruption and summit collapse, which deepened Halemaʻumaʻu crater by over 500 meters (1640 feet). Following the 2018 eruption, ground deformation rates indicated steady inflation of Kīlauea’s summit and at the end of 2018, the HVO monitoring network detected Deflation-Inflation events (DI-events) indicative that the shallow Halemaʻumaʻu magma reservoir, located approximately 1.6 km (1 mile) under Kīlauea caldera, still contained significant amounts of magma.

In late July 2019, ponded water appeared at the base of the deepest collapsed area of Kīlauea’s summit, within the Halemaʻumaʻu crater. The body of water grew into a lake as the water sought equilibrium with the surrounding groundwater.

Beginning in September 2020, increased rates of uplift were observed by Global Positioning System (GPS) stations in Kīlauea’s upper East Rift Zone and over the past month were observed in Kīlauea’s summit region.

In late November 2020, increased earthquake rates began when seismic stations recorded an average of at least 480 shallow, small-magnitude earthquakes (97% of which were less than or equal to magnitude-2) per week occurring at depths of less than 4 km (2.5 miles) beneath Kīlauea's summit and upper East Rift Zone. This compares to a rate of fewer than 180 per week following the end of Kīlauea’s 2018 eruption and through early November 2020.

On December 2, 2020, GPS stations and tiltmeters recorded a ground deformation event at Kīlauea’s summit indicative of a small dike intrusion of magma under the southern part of Kīlauea caldera.

On December 17, 2020, seismometers detected a notable increase in occurrence and duration of long-period seismic signals beneath Kīlauea’s summit, which are attributed to magmatic activity. Whereas this type of seismicity was observed on average once every few weeks following the 2018 eruption, rates have increased to over a dozen in the past several days.

Other monitoring data streams including volcanic gas and webcam imagery were stable until this eruption commenced.

Prognosis:

It is unclear how long the current eruption will continue. Kīlauea summit eruptions over the past 200 years have lasted from less than a day to more than a decade. HVO continues to monitor the ongoing eruption and all aspects of the volcano closely; HVO will report any significant changes.

Stay informed about Kīlauea by following volcano updates and tracking current monitoring data on the HVO web page (https://www.usgs.gov/volcanoes/kilauea/volcano-updates) or by signing up to receive updates by email at this site: https://volcanoes.usgs.gov/vns2/.

HVO is in constant communication with National Park Service and County of Hawai‘i County Civil Defense and other agencies responsible for public safety.

HVO is in constant communication with the County of Hawai‘i Civil Defense Agency. If anything develops that may affect your safety, you will be informed. Please sign up for Civil Defense notifications by visiting the County of Hawai‘i Civil Defense Agency webpage at http://www.hawaiicounty.gov/civil-defense/.

Contacts: askHVO@usgs.gov

Next Notice:  Kīlauea updates will be issued daily. Should volcanic activity change significantly a new VAN will be issued. Regularly scheduled updates are posted at https://www.usgs.gov/hvo

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.

Hazard Analysis:

[General hazards]

High levels of volcanic gas, rockfalls, explosions, and volcanic glass particles are the primary hazards of concern regarding this new activity at Kīlauea’s summit.

Large amounts of volcanic gas—primarily water vapor (H2O), carbon dioxide (CO2), and sulfur dioxide (SO2)—are continuously released during eruptions of Kīlauea Volcano. As SO2 is released from the summit during this new eruption, it will react in the atmosphere with oxygen, sunlight, moisture, and other gases and particles, and within hours to days, convert to fine particles. The particles scatter sunlight and cause the visible haze that has been observed downwind of Kīlauea, known as vog (volcanic smog), during previous summit eruptions. Vog creates the potential for airborne health hazards to residents and visitors, damages agricultural crops and other plants, and affects livestock operations.

Rockfalls and minor explosions, such as the ones that occurred during the 2008–2018 lava lake eruption at Kīlauea summit, may occur suddenly and without warning. This underscores the extremely hazardous nature of Kīlauea caldera rim surrounding Halemaʻumaʻu crater, an area that has been closed to the public since late 2007.

Pele's hair and other lightweight volcanic glass fragments from the lava fountains within Halemaʻumaʻu will fall downwind of the fissure vents and lava lake, dusting the ground within a few hundred meters (yards) of the vent. High winds may waft lighter particles to greater distances. Residents are urged to minimize exposure to these volcanic particles, which can cause skin and eye irritation similar to volcanic ash.


Contacts: askHVO@usgs.gov

Next Notice: The Hawaiian Volcano Observatory (HVO) continues to closely monitor Kīlauea's seismicity, deformation, and gas emissions for any sign of reactivation. HVO will continue to issue weekly Kīlauea updates on Tuesdays until further notice.

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.