Seismic Swarm S20240214.1 Near Virginia City, Nevada
A seismic swarm designated S20240214.1 was recorded 11 km NNW of Virginia City, Nevada, beginning at 12:26 on 13 February 2024 and concluding at 06:41 on 16 February 2024. Over 66 hours and 15 minutes, the sequence comprised 70 earthquakes, with magnitudes ranging from 0.3 to 3.0 and focal depths predominantly between 4 km and 7 km. The largest event, magnitude 3.0, occurred at 07:06 on 14 February at 6 km depth. Most events clustered tightly in time and space, consistent with swarm behavior rather than a classic mainshock-aftershock sequence. Virginia City lies within the Basin and Range Province of western Nevada, where ongoing crustal extension produces abundant normal faults. The local geology features Miocene volcanic rocks and sedimentary units associated with the historic Comstock Lode silver district. This tectonic setting contributes to elevated background seismicity across the region, including periodic earthquake swarms driven by fluid migration or aseismic slip on faults. Historical records document 38 swarms in the same area since 1 January 2000. Swarm frequency varied by year, with notable activity in 2008 (7 swarms), 2013 (5 swarms), 2012 and 2014 (4 swarms each), and 2015 (4 swarms). Additional swarms occurred in 2016, 2018, 2019, and 2023, underscoring the recurrent nature of clustered seismicity northwest of Virginia City. The February 2024 swarm fits this established pattern, with event depths and magnitudes aligning with prior sequences in the vicinity. No damage or felt reports beyond the immediate area were associated with the activity.
References
- U.S. Geological Survey Earthquake Hazards Program – Basin and Range tectonics and Nevada seismicity summaries
- Nevada Seismological Laboratory – Regional fault maps and historical earthquake catalogs for Storey County
- SeismoSight internal swarm classification database (S20240214.1 parameters)