Hawaiian Volcano Update: Kīlauea Summit Quake Pulse; Past Maunaloa-Kīlauea Links - December 19, 2024

This past week, Kīlauea’s underground activity cycled back up with another pulse of earthquakes mostly below magnitude 2, highlighted by “several modest upticks in seismic activity underneath the volcano’s summit, lasting from an hour to a few hours, often accompanied by minor inflation” according to the USGS Hawaiian Volcano Observatory. This shift prompted HVO to switch from weekly to daily updates, although within the past day earthquake counts are back down at the summit. 

The volcano’s East Rift has been much quieter, sitting out this cycle of earthquakes and showing deflation near the recent eruption site at Nāpau crater, although the East Rift Connector near Maunaulu inflated for the first part of the week before equilibrating in the past two days. This suggests a minor change in the dominant underground pathways accommodating the magma coming into the volcano, resulting in the clustering of activity under the summit alone. 

As pressure builds underground, these pathways may evolve further, or the volcano could force an intrusion underground, or force lava to the surface in an eruption. However, even as earthquakes signal building pressure, their activity has not been sustained or consistent, suggesting the pattern is still ramping up while the volcano can adjust in response. All activity is fully contained within Hawaiʻi Volcanoes National Park and poses no increased threat to people at this time. Volcanic gas is currently the greatest volcanic threat, especially for those with respiratory sensitivities; gas emissions are present at low levels from the summit, around the volcanic background at 70 tonnes of SO2 per day.

Maunaloa continues to inflate more quietly in the expected pattern, now 2 full years past its 2022 eruption. Wrapping up our anniversary coverage, we revisit the question of the connection between Maunaloa and Kīlauea, touching on the effects of stress transfer and pore pressure to explain the typical anti-correlation of eruptions between the two volcanoes. When Maunaloa’s 2022 eruption began, Kīlauea was also erupting, but quickly began winding down its output as visible from the stagnating circulation of its summit lava lake. Kīlauea’s lava output ended less than a week later as a result, and Maunaloa continued erupting for another week before itself shutting off. Once Maunaloa calmed, Kīlauea began ramping up again, erupting again less than a month later. This pattern has rarely been so clear in the modern era, and makes a fitting conclusion to this series. Examining details of recent activity allows us to improve our response and better anticipate public issues during future eruptions, keeping our island communities safe.

As usual, we summarize 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.

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Volcano Watch is a weekly article and activity update written by U.S. Geological Survey Hawaiian Volcano Observatory scientists and affiliates. Today's article is by Natalia Deligne, a geologist at HVO