Earthquake Swarm VS20230814.1: Seismic Activity Near Volcano, Hawaii
An earthquake swarm designated VS20230814.1 was recorded 4 km southwest of Volcano, Hawaii, on the Big Island. The sequence began at 06:51 on 13 August 2023 and concluded at 10:42 on 18 August 2023, spanning 123 hours and 50 minutes. During this period, 331 earthquakes were detected, providing valuable data on local crustal dynamics.
Analysis of the first 100 events reveals predominantly low-magnitude activity. Magnitudes ranged from 0.3 to 4.3, with the majority below 2.0. Depths were mostly shallow, concentrated between 0 and 3 km, consistent with volcanic or shallow tectonic processes. A notable outlier occurred on 13 August at 23:36:28 UTC, registering magnitude 4.3 at 25 km depth, followed shortly by a magnitude 1.9 event at the same depth. Subsequent events returned to shallower levels, indicating a brief deeper pulse amid otherwise surface-proximal seismicity.
This swarm aligns with the geological setting of the Kilauea volcano region. The Hawaiian Islands formed through hotspot volcanism, where the Pacific plate moves over a mantle plume, generating persistent magmatic activity. Kilauea, one of the world's most active volcanoes, exhibits frequent earthquake swarms driven by magma intrusion, dike propagation, and associated stress changes in the surrounding rock. The southwest flank of Kilauea, near Volcano town, lies within the East Rift Zone influence, where historical unrest has repeatedly produced similar clustered seismicity.
Long-term records show persistent swarm activity in the area. Since 1 January 2000, 90 swarms have occurred, distributed across years as follows: 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), and 2023 (7). These episodes underscore the ongoing volcanic-tectonic interaction characteristic of the Hawaiian hotspot.
Such swarms typically pose minimal direct hazard but serve as indicators of subsurface magma movement. Monitoring by agencies like the Hawaiian Volcano Observatory supports hazard assessment and eruption forecasting in this dynamic environment.
References
USGS Earthquake Catalog Hawaiian Volcano Observatory reports SeismoSight internal swarm classification VS20230814.1