Hawaiian Volcano Update: Kīlauea Eruption at Nāpau Continues Through Day 4, September 19, 2024
Over the past 4 days, Kīlauea’s eruption at Nāpau Crater has progressed through 4 different phases, in a pattern typical of Middle East Rift activity. While dynamic, all the action is contained within Hawaiʻi Volcanoes National Park, with no increased threat to communities living near the volcano’s Lower East Rift.
Due to the remote location of the eruption within the National Park, volcanic gas is the primary threat to people as emissions dramatically increase during eruptions, especially at the start. Newly active vents on the East Rift have been measured outputting 10,000 to 12,000 tonnes of SO2 per day, with inactive fissures emitting around 300 tonnes per day. This is all in addition to the 60 tonnes per day background rate issuing from the summit, such that sensitive individuals should take precautions even at greater distances downwind, including on the reopened Chain of Craters Road in the National Park.
The latest, 4th phase began yesterday at 3:15pm with a shift of active vents to the initial outbreak site above the western crater rim. So far, each new phase has erupted lava at a higher rate, with the latest creating a lava cascade down the western wall of Nāpau and thus far covering two-thirds of the crater floor. This activity was caught by the USGS Hawaiian Volcano Observatory’s redeployed S2 webcam as visible in time-lapse imagery.
Reviewing the sequence so far –
Phase 1: Brief eruption west of Nāpau, 9-10pm 9/15
Phase 2: Reactivation, 6-7pm 9/16
Phase 3: Fissures open in Nāpau, 4-5am 9/17 – ⅓ of crater floor covered in lava within ~5 hrs
Phase 4: Shift west & lava falls into Nāpau, 3:15pm 9/18 – ⅔ of crater floor covered in lava by 9/19
Monitoring signals on the volcano show little slowdown in magma leaving the summit for the East Rift, suggesting the eruption still has some time to go. Now that there is relief to the built-up underground pressure, earthquake and deformation rates in the areas surrounding the eruption have greatly decreased. All the eruptive vents have emerged within a relatively contained 1-mile segment of the rift, suggesting stability of the deeper magma pathway for now. There is no apparent effect of Kīlauea’s activity on neighboring Maunaloa, which continues its usual pattern.
As usual, we review the monitoring signals, imagery, and reports available courtesy of the USGS Hawaiian Volcano Observatory, annotating the presentation on screen as we go and discussing live viewer questions.
