(BIVN) – Episode 54 ended at 7:33 p.m. Tuesday evening, after 9 hours of continuous lava fountaining. The Volcano Alert Level for Kīlauea was lowered from WATCH to ADVISORY, and the Aviation Color Code from ORANGE to YELLOW.
Lava erupted only from the north vent of the summit caldera during the episode, reaching a maximum fountain height of approximately 500 feet (150 meters) above ground level. Neither the south vent nor the new west vent produced lava fountains during the event, the USGS Hawaiian Volcano Observatory reported.
The episode produced a maximum plume height of approximately 17,000 feet (5,200 meters) above sea level. Tephra from the eruption fell to the southwest of the vents, within the closed area of Hawaiʻi Volcanoes National Park. There was a report of trace Pele’s hair falling in the Ka‘ū district.
An abrupt switch from summit deflation to inflation at the end of the episode, as well as the resumption of low frequency tremor bursts, indicate that another episode is likely in the coming weeks, scientists say.
From the USGS HVO Episode 53 chronology:
Lava fountaining episode 54 in Halemaʻumaʻu at the summit of Kīlauea began around 10:30 a.m. HST and ended at 7:33 p.m. HST on August 25, 2026, after 9.0 hours of continuous lava fountaining from the north vent. Neither the south vent nor the new west vent (formerly the collapse pit) fountained during this episode. The instantaneous effusion rate from the north vent peaked at about 290 cubic yards (220 cubic meters) per second between 11:45 a.m. HST and 12:15 p.m. HST. The average effusion rate over the entire episode was approximately 140 cubic yards (110 cubic meters) per second. An estimated 5.2 million cubic yards (4.0 million cubic meters) of lava erupted and covered about 30% of the Halemaʻumaʻu crater floor. Seismicity followed the normal pattern for most fountaining episodes, with rapidly increasing tremor at the beginning of the episode, followed by a gradual decline through its main stages, followed by an abrupt drop at the end of the episode. The Uēkahuna tiltmeter (UWD) recorded approximately 12.7 microradians of deflationary tilt during episode 54.
Following the onset of relatively rapid summit inflation yesterday, August 24, north vent spatter was observed in overnight webcam views starting just after 7:00 p.m. HST and tremor turned from continuous to well defined gas piston cycles 5–10 minutes apart. Spattering from the north vent continued to build through the evening until after midnight when it became more continuous. Bright glow, flames, and occasional spatter were observed from the west vent and correlated with tremor peaks produced by drainback during gas piston cycles. There were only a few, rare glimpses of weak glow from the south vent.
This morning, August 25, there were two precursory overflows from the north vent: the first from 6:16 to 6:37 a.m. HST and the second from 7:27 to 8:12 a.m. HST. There were no overflows from either the west or south vents. A third north vent overflow began at 8:52 a.m. HST and continued until it transitioned into the onset of episode 53 lava fountaining at 10:30 a.m. HST. The transition from precursory activity to the onset of episode 54 lava fountaining was marked by increasing height of the north vent dome fountain, greater eruptive volume, increased deflation and rapidly increasing tremor. At this point a surging dome fountain began feeding a vigorous flow into Halemaʻumaʻu crater. The north vent lava fountain grew rapidly over the next hour and reached a peak height of approximately 500 feet (150 meters) around 12:15 p.m. HST and remained at that height until about 1:00 p.m. HST. The high fountain produced significant heat and some tephra, feeding a gas plume that reached a maximum height of about 17,000 feet (5,200 meters) above sea level based on webcam images.
By 1:30 p.m. HST on August 25, fountain heights decreased to about 350 feet (110 meters) above ground level, and plume heights decreased to 14,000 feet (4,200 meters) above sea level. Fountain heights then remained mostly constant until the early evening. However, the plume heights continue to decrease and were below 12,000 feet (3,700 meters) at this time. The fountain heights began to decrease after 6:00 p.m. HST reaching 160 feet (50 meters) just before 7:00 p.m. HST. The final fountains were about 100–200 feet (30–60 meters) high during the last half hour of the eruption, and the plume cloud was down to about 7,000 feet (2,100 meters). Episode 54 ended abruptly at 7:33 p.m. HST on August 26, with the last 3 minutes were marked by gas jetting and flames from the north vent.
Winds were out of the northeast during fountaining but decreased in velocity above the inversion layer, which was around 12,000 feet (3,650 meters) above sea level. The northeast winds carried the gas and fine ash and Peleʻs hair in the plume toward the southwest. Most tephra fall was restricted to the closed area of Hawaiʻi Volcanoes National Park, southwest of the active eruptive vents in Halemaʻumaʻu. However, HVO did also receive a report of trace Pele’s hair falling in the Ka‘ū district of the Island of Hawaiʻi.
The abrupt switch from summit deflation to inflation at the end of episode 54 and the resumption of low frequency tremor bursts indicate that another lava fountaining episode is likely in the coming weeks.
