9:15am UPDATE: HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE U.S. Geological Survey
HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey
Wednesday, July 9, 2025, 9:15 AM
KILAUEA (VNUM #332010)
19°25’16” N 155°17’13” W, Summit Elevation 4091 ft (1247 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE
Activity Summary:
Episode 28 of the ongoing Halemaʻumaʻu eruption began just after 4 a.m. HST today, July 9, 2025. High fountaining is continuing at this time, with maximum fountain heights reaching nearly 1200 feet (365 meters).
All eruptive activity remains within Hawaiʻi Volcanoes National Park, and no significant activity has been noted along Kīlauea’s East Rift Zone or Southwest Rift Zone.
Current hazards include volcanic gas emissions, along with windblown volcanic glass (Pele’s hair) and tephra that may reach roadways and communities downwind (southwest) of the summit area.
Summit Observations:
Following days of low-level gas pistoning and occasionally visible spatter and flames, activity began to increase just after 4 a.m. HST with a larger lava overflow, continuous low-level fountaining, weak deflation, and an increase in seismic tremor. Around 5:15 a.m. HST today, fountaining increased in height and vigor; at the same time, tilt began to drop sharply. High fountaining with maximum heights reaching nearly 1200 feet (365 meters) continues at the time of this update. Activity thus far – from pre-episode gas pistoning through lava overflows to the current fountaining – has been restricted to the north vent. The south vent does not show renewed activity at this time.
At the time of the onset of Episode 28, the tiltmeter near Uēkahuna (UWD) had recorded about 14 microradians of inflationary tilt since the end of episode 27. At this time, the tiltmeter has shown approximately 7.5 microradians of deflation in association with the current fountaining.
Tremor and degassing are elevated during fountaining episodes. Typical sulfur dioxide (SO2) emission rates during high fountaining are around 75,000 tonnes/day.
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. Trade winds are blowing the both volcanic gases and erupted particles (tephra, ash, and Pele’s hair) to the west and southwest of Kīlauea summit today.
- Eruption resources, including the most recent map and a timeline of eruption episodes since December 23, 2024: https://www.usgs.gov/volcanoes/kilauea/science/eruption-information
- Three Kīlauea summit livestream videos that show eruptive lava fountains are available here: https://www.youtube.com/@usgs/streams
- Summit eruption webcams: https://www.usgs.gov/volcanoes/kilauea/summit-webcams
- Volcano Watch article on gas pistoning: https://www.usgs.gov/observatories/hvo/news/volcano-watch-so-what-earth-or-least-kilauea-a-gas-piston
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 the detection limit.
Analysis:
Recent eruptive episodes have generally last less than 12 hours. Accordingly, we expect the fountaining associated with Episode 28 to end sometime later today.
In the next few days, as post-episode data comes in, we will likely be able to begin to forecast a possible window for the next episode.
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 Halema’um’a’u 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.
