Hawaiian Volcano Update: Kīlauea’s Short Southwest Rift Eruption,

Kīlauea erupted for 8.5 hours on Monday morning, June 3, 2024, leaving a small footprint of lava and extensive ground cracking. The new fissures closely aligned with those from the 1974 eruption, about 2.5 miles southwest of Halemaʻumaʻu above Kīlauea’s Southwest Rift Connector, following the trend of the Koaʻe Fault Zone. In the 3 days since, the series of 4 fissures has continued to glow and emit large volumes of volcanic gases, although decreasing with each passing day. Fully contained within a closed area of Hawaiʻi Volcanoes National Park, the eruption did not threaten any people or infrastructure, apart from gases which impacted much of the island with vog.

Although lava erupted, its small volume (0.1 to 0.4 million cubic meters) and the propagation of large ground cracks within 500 meters of Maunaiki suggests that most of this event occurred underground, as a larger volume of magma presumably moved past the active vents as an intrusion farther downrift. However, the ground tremor that accompanied this subterranean movement has decreased substantially since the eruption, and the USGS Hawaiian Volcano Observatory reports that it is “unlikely that this eruption will restart.”

While the summit of Kīlauea appears to have contracted during the eruption, suggesting a net outflow of magma, the ground tilt monitor in the South Caldera area that feeds the Southwest Rift Connector has resumed inflating, suggesting a rapid recharge into the tapped area of the magma reservoir. Much of the current sequence has its roots in the late January Southwest Rift intrusion, which seemingly opened downrift pathways and weaked the overlaying ground. The 2024 eruption progressed downrift without much seismicity at the time, which was instead focused near the summit, and lava emerged from the general area that had exhibited major ground cracking following the earlier intrusion.

There is currently no increased hazard to people, with volcanic gas emissions still the main threat to residents and visitors between eruptions. Gas measurements are higher than usual, with the most recent reported value of 5500 tonnes of SO2 per day likely higher than today’s emissions but still well above background levels. Maunaloa continues to recharge following activity in 2022, remaining relatively quiet with few earthquakes and sustained slow inflation, in addition to occasional flank movement in response to events on neighboring Kīlauea.

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.