Seismic Swarm S20081005.1: Analysis of Activity Near Beatty, Nevada

Seismic swarm S20081005.1 began at 04:48 on 5 October 2008 and concluded at 17:08 on 1 November 2008. The events were located 46 km east-southeast of Beatty, Nevada. Over 660 hours and 19 minutes, the swarm produced 359 earthquakes. Analysis of the first 100 events shows consistently low magnitudes, ranging from -0.6 to 1.2. The majority clustered between -0.5 and 0.5, with only a few reaching or exceeding 0.7. Depths remained shallow, predominantly between 3 km and 11 km, indicating activity within the upper crust. Early events on 5 October occurred at depths near 8–10 km, while later ones in the sequence occasionally shallowed to 3–6 km. This pattern reflects typical swarm behavior driven by fluid migration or slow slip rather than a single large rupture. The region around Beatty lies in the southern Walker Lane belt, a transitional tectonic zone between the Sierra Nevada and the Basin and Range Province. Active normal and strike-slip faulting accommodates regional extension and shear, producing frequent small-magnitude earthquake sequences. Historical records document 24 swarms in the area since 2000, with notable activity in 2000 (5 swarms), 2002 (7 swarms), and 2008 (5 swarms). These episodes underscore the persistent, distributed nature of seismicity in this extensional setting. No damage or felt reports were associated with S20081005.1, consistent with the microseismic character of the events. Such swarms contribute to ongoing monitoring efforts that refine understanding of fault mechanics and seismic hazard in central Nevada.

References

• SeismoSight internal swarm classification records
• USGS Earthquake Catalog (historical swarm statistics 2000–2008)
• Nevada Bureau of Mines and Geology regional tectonic summaries