Activity Summary:
Kīlauea summit eruption paused as of March 20. Based on less than 24 hours of data since the pause in eruption, preliminary estimates of a new eruptive episode may begin within the next 2-4 days in Hawai'i Volcanoes National Park. Estimates will be refined in the coming days as more data becomes available.
Episode 14 of the ongoing Halemaʻumaʻu eruption ended abruptly at 1:49 p.m. HST on March 20. Episode 14 lasted 28 hours and 23 minutes with the last 7 hours and 19 minutes consisting of fountains up to 600 feet (180 meters) high predominantly from the south vent. Kīlauea's current eruption in Halemaʻumaʻu crater within Kaluapele (the summit caldera) began on December 23, 2024. There have been 14 episodes of lava fountaining separated by pauses in activity. All eruptive activity remains within Hawai'i Volcanoes National Park. No significant activity has been noted along Kīlauea’s East Rift Zone or Southwest Rift Zone.
Current hazards include volcanic gas emissions and windblown volcanic glass (Pele’s Hair) that may impact Hawai’i Volcanoes National Park and nearby communities.
Summit Observations:
Lava flows and fountains stopped erupting from the south vent within Halemaʻumaʻu crater at about 1:49 p.m. HST on March 20. Fountains from the north vent ceased ~ 11 minutes earlier. Lava flows from episode 14 covered 75% of the Halemaʻumaʻu crater floor. Spots of orange glow can still be seen on the crater floor at night as the erupted lava continues to cool. The vents continue to degas and glow at night, indicating magma remains at shallow levels in the vent.
Deflationary tilt at the summit recorded about 6 microradians lost during this episode. Initial deflation was very rapid but slowed at 7:46 a.m. HST when north vent fountains dropped back into the cone and became intermittent. The end of the eruption was coincident with a rapid change from deflation to inflation at the summit and a decrease in seismic tremor intensity. Summit tilt changed rapidly from deflation to inflation, and seismic tremor decreased, at about the same time that the lava fountains stopped erupting on March 20. In the past 19 hours, the Uēkahuna (UWD) tiltmeter has recorded approximately 1 microradians of inflationary tilt since the end of episode 14. Seismic tremor decreased significantly at the end of episode 14 but remains above background. 1 small earthquake was recorded in the summit region over the past 24 hours.
Volcanic gas emissions remain elevated. A maximum SO2 emission rate measured in the morning on March 20 reached approximately 50,000 t/d. Based on measurements made during earlier episodes and pauses, sulfur dioxide (SO2) emission rates are likely to be approximately 1,000 t/d during the current pause. An SO2 emission rate of 1,500 t/d was measured on March 20 at 5:00 p.m. HST.
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) emissions from the East Rift Zone remain 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 14 fountaining 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.
Analysis of inflationary tilt patterns prior to the onset of each fountaining episode allows a time window of probability for the onset of new episodes to be estimated. These are calculated using both minimum inflation necessary to start a new eruption and the rate of inflation. If current inflation rates at UWD continue, preliminary estimates (based on less than 24 hours of data since the pause in eruption) suggest that the most likely window of time for a new episode to begin is between Sunday, March 23 and Tuesday, March 25. This estimate may be revised in future updates as more data becomes available.
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.
