Seismic Swarm VS20221231.1: Analysis of Activity on the Island of Hawaii
The seismic swarm designated VS20221231.1 occurred on the Island of Hawaii from 08:54 on 30 December 2022 to 15:16 on 2 January 2023. Over 78 hours and 21 minutes, 44 earthquakes were recorded. This event aligns with the region's established pattern of volcanic-related seismicity driven by magma movement beneath the Hawaiian hotspot.
The Island of Hawaii, also known as the Big Island, sits atop an active volcanic system formed by the Pacific plate's movement over a mantle plume. Primary volcanoes include Kilauea and Mauna Loa, where repeated magma intrusions trigger earthquake swarms. These swarms typically feature numerous low-magnitude events at shallow depths, reflecting fluid migration and crustal stress adjustments rather than large tectonic releases. Depths in this swarm ranged from 0 to 8 km, with the majority clustered between 0 and 2 km, consistent with near-surface volcanic processes.
Magnitudes remained modest, spanning 0.2 to 2.1. The strongest events reached 2.1 on 31 December 2022 at depths of 0 km. Activity peaked on 31 December, with over 30 events concentrated in the morning hours, followed by a sharp decline on 1–2 January. Notable sequences included multiple events between 05:02 and 05:55 on 31 December, and additional clusters around 12:00–15:00 and 19:00–22:00 that day. Later events on 1 January occurred at slightly greater depths, including one at 8 km, before the swarm concluded with a final 0.7-magnitude quake on 2 January.
Historical records indicate 93 swarms on the Island of Hawaii since 1 January 2000. Yearly counts show variability: 3 in 2000, 1 in 2001, 7 in 2003, 8 in 2004, 1 in 2005, 2 in 2006, 4 in 2007, 1 in 2008, 3 in 2011, 4 in 2012, 1 in 2013, 2 in 2014, 5 in 2015, 2 in 2016, 2 in 2017, 9 in 2018, 4 in 2019, 14 in 2020, 11 in 2021, and 9 in 2022. Elevated counts in recent years correspond to periods of heightened volcanic unrest, including the 2018 Kilauea eruption and Mauna Loa's 2022 activity.
Such swarms contribute to ongoing monitoring of volcanic hazards. Shallow, low-magnitude sequences like VS20221231.1 rarely produce significant surface damage but provide critical data on subsurface dynamics. Continued observation supports refined models of magma pathways and eruption forecasting in this high-seismicity volcanic environment.
References
- SeismoSight internal swarm classification data for VS20221231.1
- USGS Hawaiian Volcano Observatory geological summaries on Hawaii hotspot volcanism and swarm characteristics