UPDATE – (10:45 a.m.) – Gas pistoning continued in the north vent on Wednesday morning, and intermittently in the south vent. Webcams captured small lava overflows from the north vent, which occurred during the gas pistoning cycles. 

The lava overflows mark the start of intermittent precursory eruptive activity leading up to Episode 33. 

From the USGS Hawaiian Volcano Observatory updated posted at 9:32 a.m. HST: 

Summit inflation continues and episode 33 lava fountaining is likely in the next 1-4 days. Models suggest episode 33 is likely to begin between September 17 (today) and 20 but could start later if the rate of inflation decreases. Glow was visible from the north and south vents in the livestream overnight, and gas pistoning has caused several small vent overflows this morning 8:38 AM HST marking the start of intermittent precursory eruptive activity.

Summit Observations:

The Uēkahuna tiltmeter (UWD) has recorded approximately 21.3 microradians of inflationary tilt since episode 32 ended, and inflation continues this morning. Glow in the north vent has been visible for the past several days, and over the past 24 hours the magma column has been rising and falling in the vent in cycles (gas pistoning), which has been common in the build up to lava fountaining episodes. This morning, several of the gas piston cycles resulted in small amounts of lava briefly overflowing the crater at the north vent. Intermittent glow overnight at the south vent suggests gas pistoning in that vent as well.

Elevated degassing continues from the vent. Average sulfur dioxide (SO2) emission rates during inter-episode pauses are typically 1,200 to 1,500 t/d, though emission rates vary on short timescales in association with gas pistoning.

FIRST REPORT

USGS webcam shows the overnight glow at the north and south vents at the summit

(BIVN) – The next episode of lava fountaining in the ongoing eruption of Kīlauea volcano could begin at any moment.

Scientists with the USGS Hawaiian Volcano Observatory say revised models suggest Episode 33 is now likely to start between today, September 17, and Saturday, September 20.

“The appearance of magma within the north vent suggests that episode 33 might arrive earlier than tilt-based models predict,” the Observatory noted on Tuesday night, noting that Episode 32 showed similar behavior.

Gas pistoning events were occurring at the north vent on Tuesday. “Magma rises and becomes visible in the vent,” the Observatory scientists described. “Rapid drainback is marked by small spatter fountains and a spike in seismic tremor, 10 to 15 minutes apart.”