Halemaʻumaʻu eruption · episode 33 of 55
Kīlauea episode 33
Episode 33 of Kīlauea's Halemaʻumaʻu eruption began at 3:11 a.m. HST on September 19, 2025 and ended at 12:08 p.m. HST the same day. USGS gives the duration as 9 hours. HVO's Uēkahuna tiltmeter (UWD) recorded 17 microradians of deflation during the episode. HVO notes: North and south vents active; north vent inclined.
Episode 33 at a glance
- Start (HST)
- September 19, 2025, 3:11 a.m.USGS timeline
- End (HST)
- September 19, 2025, 12:08 p.m.USGS timeline
- Duration
- 9 hoursUSGS timeline
- UWD tilt (deflation)
- 17 microradiansHVO notice
- Max fountain height
- about 249 mUSGS timeline
- Lava erupted
- about 5.7 million m³USGS timeline
- Pause that followed
- 12 daysUSGS timeline
In HVO's words
The sentences these figures come from, quoted from USGS Hawaiian Volcano Observatory notices.
“The tiltmeter at Uēkahuna (UWD) has recorded approximately 18 microradians of inflationary tilt since the end of the episode 33, during which it recorded 17 microradians of deflationary tilt.”
HVO notices about episode 33
- Volcano Activity Notice · Sep 19, 2025, 3:40 a.m. HST
- Volcano Activity Notice · Sep 19, 2025, 12:49 p.m. HST
- Status Report · Oct 1, 2025, 12:30 a.m. HST
Daily updates: USGS Kīlauea volcano updates. Full table: USGS Timeline of Eruptive Episodes.
Times are Hawaiʻi-Aleutian Standard Time (HST). Start and pause times, durations, fountain heights and lava volumes come from the USGS Hawaiian Volcano Observatory's Timeline of Eruptive Episodes; tilt figures and episodes not yet in that table are quoted from HVO notices. USGS describes these as unreviewed, preliminary estimates that are subject to revision. Durations for episodes 17 and earlier may include precursory activity, and HVO rounds durations to the nearest hour, half-hour or day. A blank cell means HVO hasn't published that figure in a form we could read; we don't estimate it.
Credit: U.S. Geological Survey. This archive is generated automatically and is not an official USGS product.