Seismic Swarm S20080614.2: Analysis of Activity Near Beatty, Nevada

Seismic swarm S20080614.2 occurred 48 km east-southeast of Beatty, Nevada, in the southern Great Basin. The sequence began at 00:45 UTC on 14 June 2008 and concluded at 02:17 UTC on 17 June 2008, spanning 73 hours and 31 minutes. During this interval, 42 earthquakes were recorded, with magnitudes ranging from -0.7 to 0.5 and focal depths primarily between 4 km and 10 km.

The events displayed typical swarm characteristics: no dominant mainshock, gradual onset, and fluctuating activity without clear aftershock decay. The largest events reached magnitude 0.5 on 14 June at 05:30 and 15:15. Depths clustered around 7–8 km, consistent with shallow crustal faulting in the region.

This swarm fits a broader pattern of seismicity in southern Nevada. Since 1 January 2000, 22 swarms have been documented in the area. Prior swarms occurred in 2000 (5), 2002 (7), 2003 (2), 2005 (2), 2006 (1), 2007 (2), and 2008 (3). Such recurrent low-magnitude swarms reflect ongoing extensional tectonics within the Basin and Range province, where distributed normal faulting accommodates regional strain.

The Beatty area lies near the transition between the Walker Lane shear zone and the central Nevada seismic belt. Quaternary faults in the vicinity, including segments of the Bare Mountain and Fluorspar Canyon fault systems, contribute to the observed microseismicity. Depths of 4–10 km align with the brittle-ductile transition zone in this portion of the crust, where small-magnitude events predominate.

Regional monitoring by the Nevada Seismological Laboratory and USGS networks has improved detection of such swarms since the early 2000s. The 2008 sequence underscores the value of dense instrumentation for characterizing background activity near former nuclear testing sites and proposed geologic repositories.

References
U.S. Geological Survey Earthquake Catalog
Nevada Seismological Laboratory swarm database
SeismoSight internal classification records