Earthquake Swarm VS20230531.1: Seismic Activity Near Volcano, Hawaii
An earthquake swarm designated VS20230531.1 was recorded 5 km southwest of Volcano, Hawaii. The sequence began at 18:35 on 30 May 2023 and concluded at 02:15 on 5 June 2023, spanning 127 hours and 39 minutes. During this period, 108 earthquakes were detected.
Analysis of the first 100 events reveals predominantly low-magnitude activity. Magnitudes ranged from 0.1 to 2.8, with the majority falling between 0.4 and 1.9. Depths were generally shallow, concentrated between 0 and 4 km, though isolated events reached 22 km and 7 km. The initial event on 30 May registered magnitude 1.9 at 1 km depth. Subsequent activity on 31 May included multiple events below magnitude 1.0, interspersed with stronger shocks such as magnitude 1.9 at 0 km depth. Into early June, magnitudes increased slightly, peaking at 2.8 on 1 June at 2 km depth and 2.6 on both 1 June and 3 June. Most events clustered within the first 48 hours, with a gradual decline thereafter.
This swarm aligns with patterns observed in the region since 2000, during which 93 swarms have occurred. Annual totals include 13 swarms in 2020, 9 in both 2018 and 2021, and 8 in 2003, 2022, and 2003. Earlier years showed lower frequencies, such as single swarms in 2001, 2005, 2008, and 2013.
The Volcano area lies on Hawaii's Big Island within the volcanic system associated with Kilauea. Seismic swarms here commonly result from stress changes linked to magma movement along rift zones and flank adjustments. Shallow depths in the recorded events are consistent with upper crustal processes typical of this tectonically active setting. Historical monitoring indicates recurrent swarm activity tied to the island's ongoing volcanic evolution.
References
USGS Earthquake Catalog Hawaii Volcano Observatory reports SeismoSight internal swarm classification data