Activity Summary:
Kīlauea stopped erupting this morning in Hawaiʻi Volcanoes National Park. Episode 9 of the ongoing summit eruption paused at 8:43 a.m. HST, February 12.
The was the ninth episode of Kīlauea's ongoing eruption in Halemaʻumaʻu crater within Kaluapele (the summit caldera) that began on December 23, 2024. Fountain-fed lava flows from the north and south vents erupted onto the crater floor for over 22 hours. There have been 9 episodes of lava fountaining separated by pauses in activity. All recent eruptive activity has occurred in Hawaiʻi Volcanoes National Park. No significant changes have been noted along Kīlauea’s East Rift Zone or Southwest Rift Zone.
Ongoing hazards include volcanic gas emissions and windblown volcanic glass (Pele’s Hair) that may impact Hawaiʻi Volcanoes National Park and nearby communities.
Summit Observations:
Episode 9 ended at 8:43 a.m. HST this morning, February 12, after 22 and a half hours of lava fountaining.
Fountains began erupting from the north vent at 10:16 a.m. HST yesterday, February 11, and slow effusion of lava began from the south vent shortly afterward, at around 10:50 a.m. HST. Vigorous, sustained fountains from the north vent reached heights of up to 330 feet (100 meters) during the initial hours of episode 9 and were averaging heights of up to 160-200 feet (50-60 meters) last night, while bifurcated south vent fountains were lower, reaching 80-100 feet (25-30 meters) high last night, February 11. This morning, February 12, effusion rates were decreased compared to yesterday. Fountains observed before 8:30 a.m. HST this morning were lower than yesterday and variable in height, reaching 100-150 feet (30-50 meters). Fountains continued to slowly drop until the vents started shutting down around 8:30 a.m. HST. Lava fountaining stopped from the north vent at 8:30 a.m. HST followed by large decrease in vigor of fountains from the south vent a few minutes later. A small amount of lava continued to erupt from the south vent until at 8:43 a.m. HST, when episode 9 ended.
New lava flows erupted during episode 9 traveled approximately half a mile (about a kilometer) across the floor of Halemaʻumaʻu and covered approximately 50-60% of Halemaʻuʻmaʻu floor.
The Uēkahuna tiltmeter (UWD) switched from inflation to deflation, and seismic tremor increased, at about the same time lava flows began erupting onto the crater floor yesterday morning, February 11, at 10:16 a.m. HST. UWD recorded nearly 13 microradians of deflationary tilt during the episode 9 eruption but switched to inflation as the vents shut down around 8:30 a.m. HST. Seismic tremor remains elevated but decreased with the end of episode 9. No significant earthquakes were recorded in the summit region over the past 24 hours.
Wind conditions and the timing of episode 9 prevented accurate measurements of the sulfur dioxide (SO2) emission rate. SO2 emission rates during episode 9 are estimated to have been 10,000 t/d or higher based on emissions measured during earlier episodes. During eruptive pauses, SO2 emission rates are lower and typically around 1,000 t/d.
Strands of volcanic glass known as Pele’s Hair have been reported on surfaces throughout the summit area of Hawai’i Volcanoes National Park and surrounding communities.
Rift Zone Observations:
Rates of seismicity and ground deformation remain very low in the East Rift Zone and Southwest Rift Zone with no significant earthquake activity in the past 24 hours. Sulfur dioxide (SO2) from the East Rift Zone remains below detection limit.
Analysis:
The current eruption is marked by episodic fountaining not seen in any of the other Halemaʻumaʻu eruptions since 2020. Fountains and lava flows have erupted from two vents that we refer to as the north vent and south vent. The previous episodes lasted from a few hours to over a week. Each fountaining episode has been accompanied by strong deflation of the summit region. Pauses between the fountaining episodes have been marked by an immediate change from deflation to inflation as the magma chamber recharges and repressurizes.
Episode 9 lasted for 22 hours and 30 minutes. The rapid change from deflation to inflation at the same time the eruption paused suggests another episode will take place but there is not enough information to establish a likely time window for the next episode this morning.
Timeline of eruptive episodes since December 23, 2024: https://www.usgs.gov/volcanoes/kilauea/science/eruption-information
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.
Hazards:
The eruption has been occurring within a closed area of Hawai'i Volcanoes National Park. High levels of volcanic gas—primarily water vapor (H2O), carbon dioxide (CO2), and sulfur dioxide (SO2)—are the primary hazard of concern, as this hazard can have far-reaching effects downwind. As SO2 is continuously released from the summit during an eruption, it will react in the atmosphere to create the visible haze known as vog (volcanic smog) downwind of Kīlauea. Vog information can be found at https://vog.ivhhn.org/.
Additional hazards include Pele's hair and other volcanic fragments from lava fountains. Pele's hair are strands of volcanic glass often produced by lava fountaining activity. Volcanic fragments can fall on the ground within a few hundred yards (meters) of the eruptive vent(s), or on the western caldera rim downwind of the vent(s). Strong winds may waft light particles to greater distances downwind. Once they are on the ground, they can sometimes cluster and tangle together giving it the appearance of a tumbleweed. The extent of Pele's hair is dependent on lava fountaining activity and current wind conditions. Residents and visitors should minimize exposure to these volcanic particles, which can cause skin and eye irritation. More information about how Pele's hair is formed is available here: https://www.usgs.gov/observatories/hvo/news/volcano-watch-peles-hairs-a-beautiful-hazard-island-hawaii. A Frequently Asked Questions document developed for the 2022 Mauna Loa eruption includes information about potential health effects of Pele's hair and is available here: https://vog.ivhhn.org/sites/default/files/FAQ_on_air_quality_and_health_during_Mauna_Loa_eruption_v1.6.pdf
Hawaiian 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 also remain around Kīlauea caldera from Halemaʻumaʻu crater wall instability, ground cracking, and rockfalls that can be enhanced by earthquakes within the area closed to the public. 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.
For discussion of Kīlauea hazards, please see: https://www.usgs.gov/observatories/hawaiian-volcano-observatory/hazards.
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.