Hawaiian Volcano Update: Moving Magma Trembles Kīlauea, April 25, 2024
Over the past week, deeper earthquakes increased in frequency 5 to 6 miles below Kīlauea, with shallower quakes in the south caldera still ongoing but spreading to include the nearby East Rift Connector. The deeper activity peaked on April 19, and after slowing for three days has now resumed providing frequent long-period signals that indicate the movement of magma within the volcano, even as the ground surface of the volcano continues to swell.
As a result of this heightened state of unrest, the USGS Hawaiian Volcano Observatory began issuing daily updates for Kīlauea on April 20, but the volcano remains at the Advisory alert level and aviation color code Yellow. “This activity appears to have been deeper than normal activity that has preceded recent summit eruptions” according to USGS-HVO, while noting the uncertainty of the situation and the usual potential for an eruption around the summit.
The seismic activation of the East Rift Connector may be related to renewed filling of the Koaʻe Fault Zone south of the summit, which has continued to move and adjust following the massive intrusion on January 31. As has been the story for 7 months now, magma continues to feed robustly into Kīlauea and the volcano has been able to stretch to accommodate. Some weeks filling appears centered on the Koaʻe faults, some weeks the south caldera, some weeks the main caldera, and some weeks in the Southwest Rift Zone. The East Rift Connector has also been sporadically active since this phase of Southwest Rift activation began last October. Still, despite all the dynamic changes near Kīlauea’s summit, the Middle and Lower East Rift show no significant changes and no increased threat to people. Volcanic gas emissions are still the main current threat to residents and visitors between eruptions, but remain relatively low around 50 tonnes of SO2 per day, still a concern for sensitive individuals nearby.
Maunaloa continues to recharge following its 2022 eruption, overall remaining quiet with few earthquakes and sustained slow inflation. Maunaloa’s southeast flank is affected by Kīlauea’s active southwest flank, with Kīlauea recently pushing back on it due to its building magma pressure. This has produced some variable signals within the overall filling, stable trend.
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. As a bonus this week, we present a shortened recap and review of the USGS presentation on “How do we monitor volcanoes using earthquakes?” (and sound) from Volcano Awareness Month in January 2024.
