Kīlauea is not erupting. Episode 30 of the ongoing Halemaʻumaʻu eruption ended abruptly at 12:55 p.m. HST on August 6 after 12 hours of continuous fountaining. Lava fountains reached up to 165 ft (50 m) and erupted lava covering 80% of the crater floor during this episode. A new fissure vent that transected the south wall of Halemaʻumaʻu ceased erupting at 4:40 a.m. HST on the morning of August 6. Volcanic gas emissions have greatly decreased. Models now show that episode 31 fountains are likely to start between August 18 and August 21. The window has been shifted a day later due to overnight slowing of inflation.
Summit Observations:
Moderate to occasionally strong glow persistent glow was visible at both the north vent and the cracks above it overnight. There was no glow from the south vent or the southern fissure. Low to moderate continuous tremor and along with weak low-frequency tremor bursts have been observed over the past 4 days. The low-frequency tremor bursts are characteristic of gas pistoning of magma. Variations in gas-pistion events are consistent with long term variability of shallow seismicity between episodes. The onset and strengthening of glow within the north vents may indicates that magma is slowly getting closer to the surface. Images from an overflight on August 6th showed that episode 30 flows had covered nearly 80% the Halemaʻumaʻu crater floor, which now includes the old down dropped block.
The Uēkahuna tiltmeter (UWD) recorded about 22.5 microradians of deflationary tilt during this episode. 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. The Uēkahuna tiltmeter (UWD) has recorded just under 18 microradians of inflationary tilt since the episode ended.
Elevated degassing continues from the vent. Average sulfur dioxide (SO) emission rates during inter-episode pauses are typically 1,200 to 1,500 t/d, though emission rates vary on short time scales in association with gas pistoning.
Strands of volcanic glass known as Pele's hair are present throughout the summit area of Hawaiʻi Volcanoes National Park and surrounding communities and can be remobilized by wind even after fountaining has ceased.
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 outside of the summit. Sulfur dioxide (SO) emissions from the East Rift Zone remain below the detection limit.
Analysis:
Current inflation rates have slowed to less than 1 microradian a day which is slower than the normal inflation rate late in the repose period. Models now show the possible onset of episode 31 fountains to likely be between August 18 and August 21 with the most likely period being August 18 to August 19. If increasing vent elevation (see below) is factored into the model the likely window for the onset of fountaining is August 19 to August 22. Any changes in inflation rate will affect the models. Periods of no inflation or deflation, as seen prior to episode 30, cannot be forecast and will delay the onset of the next episode.
NOTE: The V3 camera is currently in Black and White Infrared Mode at night and is much more sensitive to heat and light than the V1 camera at this time.
The injection of a shallow dike resulted in the new southern fissure vent at the onset of episode 30. Dike emplacement in the south caldera suggests that eruptive pressure continues to increase as the vent elevation gets higher and magma can be injected into weak areas of the surrounding summit. It is possible this could result in permanent change in the vent locations and eruptive behavior. Currently, there are no indications that any eruptive activity would occur outside of the summit region. Kīlaueaʻs East Rift Zone continues to contract, indicating no magma is entering that part of the system.
The current eruption has been characterized by episodic lava fountaining not seen in any eruptions since the 1983-86 episodic fountains at the beginning of the Puʻuʻōʻō eruption. Lava fountains and flows have erupted from two vents within Halemaʻumaʻu crater that we refer to as the north vent and south vent. Each of the previous fountaining episodes lasted from a few hours to over a week and was accompanied by strong deflation of the summit region. Pauses between the fountaining episodes have been marked by an immediate switch from deflation to inflation as the magma chamber recharges and repressurizes. Fountaining episodes have occurred approximately once per week since the start of the current eruption on December 23, 2024.
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:
This episodic eruption is occurring within a closed area of Hawai'i Volcanoes National Park. High levels of volcanic gas -- primarily water vapor (HO), carbon dioxide (CO), and sulfur dioxide (SO) -- are one major hazard of concern, as this hazard can have far-reaching effects downwind. As SO 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. SO and vog may cause respiratory and other problems at high concentrations. Further information on vog can be found at https://vog.ivhhn.org/.
Another major hazard is fallout of Pele's hair and other volcanic fragments from lava fountains. Pele's hair is strands of volcanic glass often produced by lava fountaining activity that can be carried well over 10 miles (15 kilometers) from the vent. Other hot glassy volcanic fragments (tephra) including volcanic ash, pumice, scoria, and reticulite can fall on the ground within 1-3 miles (1-5 kilometers) of the eruptive vent(s), with the highest concentrations immediately downwind of the vent(s). Various volcanic fragments have fallen on Highway 11 west of Hawai'i Volcanoes National Park at times, depending on wind and eruption conditions. Strong winds may waft light particles, including Pele's hair, to greater distances downwind. Once on the ground, Pele's hair can sometimes cluster and tangle together, giving it the appearance of a tumbleweed. The extent of Pele's hair deposition is dependent on lava fountaining activity and wind conditions. Residents and visitors should minimize exposure to Pele's hair and other glassy volcanic fragments, which can cause skin and eye irritation and can also contaminate catchment water supplies. More information about how Pele's hair, its hazards, and what to do is available here: https://www.usgs.gov/observatories/hvo/news/volcano-watch-recent-lava-fountains-highlight-peles-hair-hazards. A recently updated Frequently Asked Questions document that includes information about potential health effects of Pele's hair is available here: https://vog.ivhhn.org/sites/default/files/PelesHair_FAQs_v2.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.