Seismic Swarm VS20240406.1: Analysis of Activity Near Volcano, Hawaii

A seismic swarm designated VS20240406.1 was recorded southwest of Volcano, Hawaii, from 07:02 on 5 April 2024 to 05:21 on 8 April 2024. Over 70 hours and 18 minutes, 42 earthquakes occurred in this 7 km SW location. The events exhibited magnitudes ranging from 1.1 to 2.6, with the majority clustered between 1.2 and 2.4. Depths were predominantly shallow, at 0–1 km, though isolated events reached 6 km, 26 km, and 31 km.

This swarm reflects typical patterns of clustered seismicity in the region. Multiple paired events occurred at identical timestamps with slightly varying magnitudes and depths, consistent with rapid stress adjustments along volcanic structures. Activity peaked on 5–6 April before tapering, concluding after a final magnitude 1.7 event at 2 km depth.

The Hawaiian Islands lie above a mantle hotspot, driving ongoing volcanic construction through the Pacific plate. The swarm location places it within the influence of Kilauea volcano, one of Earth’s most active systems. Kilauea’s summit and rift zones experience frequent earthquake swarms linked to magma intrusion, dike propagation, and hydrothermal fluid movement. Shallow depths in this swarm align with upper-crustal processes commonly observed around the volcano’s southwest flank and adjacent faults.

Kilauea has produced persistent eruptive activity for centuries, punctuated by major episodes such as the prolonged Puʻuʻōʻō eruption (1983–2018) and the 2018 lower East Rift Zone event that destroyed hundreds of structures. Seismic swarms often precede or accompany these episodes, serving as indicators of subsurface magma movement. The broader area also hosts Mauna Loa, whose flank interactions contribute to regional stress fields.

Historical records document 107 swarms in the vicinity since 1 January 2000. Yearly counts show variability: 2000 (3), 2001 (1), 2003 (8), 2004 (5), 2005 (1), 2006 (2), 2007 (4), 2008 (1), 2011 (3), 2012 (4), 2013 (1), 2014 (2), 2015 (3), 2016 (2), 2017 (2), 2018 (9), 2019 (4), 2020 (13), 2021 (8), 2022 (7), 2023 (22), and 2024 (2 to date). Elevated counts in 2020 and 2023 coincide with periods of heightened volcanic unrest at Kilauea.

Such swarms are integral to monitoring volcanic hazards. While most remain non-eruptive, they provide data on crustal deformation and fluid dynamics. Continued surveillance by the Hawaiian Volcano Observatory supports timely assessments of evolving activity.

References

USGS Hawaiian Volcano Observatory – Kilauea activity summaries (2024).
Smithsonian Institution Global Volcanism Program – Kilauea reports.
Hawaii State Earthquake Data Archive – Swarm statistics 2000–2024.