Seismic Swarm S20260410.1: Activity Near Volcano, Hawaii

Seismic swarm S20260410.1 occurred 1 km south of Volcano, Hawaii, on the Island of Hawaiʻi. The sequence began at 20:28 on 9 April 2026 and concluded at 22:16 on 10 April 2026, lasting 25 hours and 47 minutes. During this period, 25 earthquakes were recorded.

The events were predominantly low-magnitude, with the largest reaching 2.6. Most hypocenters were shallow, at depths of 0–1 km, though several occurred between 27 and 31 km. The timing clustered heavily in the early morning hours of 10 April, with multiple events near 02:25 and 03:03. Later activity tapered, ending with a final 0.5-magnitude quake at 22:16.

This swarm reflects typical unrest patterns driven by the active volcanic setting of Kīlauea. The region lies above the Hawaiian hotspot, where magma ascent and movement along rift zones and the south flank generate frequent microseismicity. Shallow events often indicate brittle failure in the volcanic edifice, while deeper quakes may relate to deeper magma transport or décollement slip.

Since 2000, 114 swarms have been documented in the area. Annual counts show variability, with notable increases in 2018 (9 swarms), 2020 (11), 2023 (20), and 2024 (14). These episodes commonly precede or accompany eruptive phases or intrusive events at Kīlauea, underscoring the persistent tectonic and magmatic stresses in the region.

The swarm’s characteristics align with historical observations of short-duration, low-magnitude clusters that release accumulated strain without immediate surface rupture. Continued monitoring remains essential given the proximity to populated areas and the national park.

References

USGS Hawaiian Volcano Observatory reports on Kīlauea seismicity and swarm statistics (2000–2024).
Hawaiian hotspot geology summaries from peer-reviewed volcanology literature.