Hawaiian Volcano Update: Aftermath of Kīlauea’s Southwest Rift Eruption
Following Kīlauea’s short Southwest Rift eruption on June 3, its fissures continued to spew gas for several days and glow for about a week, but now the glow has ceased and volcanic gas emissions are approaching background levels. As gas pollution was the major human impact from the eruption, communities island-wide have welcomed this change after a number of voggy days last week. Gas emissions dropped from 15,000 tonnes per day on June 3 to 5,500 t/d on June 4, then again to 400 t/d on June 6, and to 350 t/d on June 10, where background levels are typically less than 100 t/d.
Magma continued to intrude the Southwest Rift for several days as evidenced by continued tremor beneath the eruption site, with satellite radar data indicating it progressed another 4 miles beyond the new eruptive fissures, which are 3 miles from Kīlauea summit themselves. Seismicity resumed fairly quickly around the summit region after a few days following the eruption, expressing in the South Caldera, Upper Southwest Rift, and Upper East Rift as magma continues to feed into the volcano and repressurize the summit region. Ground tilt and GPS monitors also show that inflation resumed at a relatively high rate after 2 days, both in the Southwest Rift and summit, which continues today at a slower rate.
As the 2024 eruption occurred right next to the December 1974 fissures, some comparisons serve to illustrate the dynamics of this region of Kīlauea. The 1974 eruption produced 10 million cubic meters in 6 hours, covering about 3 square miles with lava flows less than 5 feet thick, while the 2024 event only produced 0.1-0.4 million cubic meters in 8.5 hours, with similarly thin lava flows covering less than 0.25 square miles. While we are still witnessing the progression following our recent eruption, in 1974 magma intruded farther down the Southwest Rift and earthquakes continued to move down all the way to the coast for the following 6 weeks, after which the volcano quieted for nearly a year. In the 1974 case, the movement of the southwest part of Kīlauea’s south flank seemed to be impactful in that it set the scene for a larger south flank earthquake near Kalapana at the end of 1975, which eventually facilitated the opening of magma pathways to erupt on the middle East Rift Zone at Puʻuʻōʻō. A lot would still need to happen in 2024 to lead to a similar situation in the future, as thus far the two eruptions and intrusions have major differences apart from their location, brevity, and character of lava flows. For now, there is no increased threat to people as a result of the recent volcanic events.
Neighboring to the north, Maunaloa continues to recharge following activity in 2022, remaining relatively quiet with few earthquakes and sustained slow inflation. Occasional flank movement on Maunaloa has also been occasionally evident in response to events on 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.
To support our productions please like, share and subscribe, and consider making a donation at https://hveri.org/donate .
