Seismic Swarm S20100604.1: Analysis of Microearthquake Activity Southeast of Beatty, Nevada
Seismic swarm S20100604.1 occurred approximately 47 km southeast of Beatty, Nevada, beginning at 08:02 on 3 June 2010 and concluding at 15:22 on 4 June 2010. Over this 31-hour, 19-minute period, 32 earthquakes were recorded. Magnitudes ranged from -0.7 to 2.0, with the majority of events registering below 0.5. Depths clustered tightly between 7 and 10 km, indicating a shallow crustal source consistent with regional extensional faulting.
The sequence lacked a dominant mainshock, a hallmark of swarm behavior where energy releases gradually through numerous small events rather than a single large rupture followed by aftershocks. The largest event, magnitude 2.0, occurred on 3 June at 14:58:26 at 10 km depth. Subsequent activity remained diffuse, with events distributed across both days without clear temporal clustering around any individual shock.
This swarm unfolded within the Basin and Range Province, specifically along the southern margin of the Walker Lane tectonic belt. The region accommodates northwest-directed dextral shear between the Pacific and North American plates through a network of normal and strike-slip faults. Quaternary fault scarps and active hydrothermal systems near the Amargosa Desert and Timber Mountain caldera complex contribute to elevated microseismicity. Depths of 7–10 km align with the brittle-ductile transition zone typical of this extensional regime, where fluid migration or minor magmatic movement can trigger swarm sequences.
Historical records indicate persistent swarm activity in the area. Since 1 January 2000, 30 swarms have been documented through 2010, distributed across years as follows: four in 2000, seven in 2002, two in 2003, two in 2005, one in 2006, two in 2007, six in 2008, four in 2009, and two in 2010. This pattern underscores the recurrent nature of low-magnitude, swarm-type seismicity driven by the area's structural complexity.
- Nevada Seismological Laboratory regional catalogs
- USGS Earthquake Hazards Program fault and seismicity databases
- SeismoSight internal swarm classification records