Seismic Swarm VS20241223.1 Recorded Southwest of Volcano, Hawaii

An earthquake swarm designated VS20241223.1 occurred 7 km southwest of Volcano, Hawaii, on December 23, 2024. The sequence began at 02:22 UTC and concluded at 22:03 UTC, spanning 19 hours and 41 minutes during which 35 events were detected.

Magnitudes ranged from 0.9 to 2.7, with the majority of events registering between 1.5 and 2.6. Depths remained shallow, predominantly at 0–2 km. The largest event reached magnitude 2.7 at 12:21 UTC. Activity clustered notably between 11:36 and 12:27 UTC, when 18 earthquakes occurred within roughly one hour, including several events of magnitude 2.3–2.7. A secondary pulse appeared earlier around 08:40–09:37 UTC.

This swarm aligns with patterns observed in the region since 2000, during which 114 swarms have been documented. Annual counts show variability, with elevated activity in 2023 (20 swarms) and 2020 (13 swarms), followed by 14 swarms recorded through 2024.

The swarm location lies on the flanks of Kīlauea volcano within the Hawaii hotspot volcanic system. Kīlauea, one of the world’s most active shield volcanoes, experiences frequent shallow seismicity driven by magma transport through rift zones and summit reservoirs. Such swarms commonly reflect brittle failure induced by dike propagation or pressure changes in the magmatic plumbing system. The East Rift Zone and adjacent areas have hosted repeated intrusive events over decades, consistent with the shallow depths and moderate magnitudes observed here.

Geological monitoring in this sector benefits from the dense instrumentation maintained by the U.S. Geological Survey Hawaiian Volcano Observatory. Continuous GPS, tilt, and seismic networks have documented similar swarms preceding both intrusive and eruptive episodes at Kīlauea throughout its historical record, which includes sustained activity phases from the 1980s onward and the 2018 lower East Rift Zone eruption.

References

USGS Hawaiian Volcano Observatory – Kīlauea monitoring reports
USGS Earthquake Catalog – Hawaii region data
Smithsonian Institution Global Volcanism Program – Kīlauea volcano profile