Seismic Activity: The May 2006 Earthquake Swarm Northwest of Beatty, Nevada
The earthquake swarm designated S20060526.1 was recorded 49 km northwest of Beatty, Nevada. It began at 00:09 on 26 May 2006 and concluded at 17:52 on 30 May 2006. Over a period of 113 hours and 43 minutes, the swarm comprised 173 earthquakes. Analysis of the first 100 events reveals predominantly low-magnitude activity. Magnitudes ranged from 0.2 to 2.1, with the majority falling between 0.6 and 1.1. Depths were consistently shallow, concentrated between 0 and 8 km. The sequence initiated with several events near magnitude 1.0 at depths of 4–5 km on 26 May, followed by a gradual increase in frequency and occasional peaks reaching 1.9 and 2.1 later that day and into 27 May. Activity remained focused in the upper crust, consistent with typical swarm behavior driven by fluid migration or minor fault slip rather than a single large rupture. This swarm represents the fourth such episode in the region since 2000. Earlier swarms occurred in 2000, 2001, and 2002, each limited to a single event cluster. The 2006 sequence was markedly more prolific, indicating episodic unrest along local structures. The Beatty area lies in the southern Great Basin portion of the Basin and Range Province. This tectonic setting features active crustal extension accommodated by normal faults and distributed shear. Regional seismicity is influenced by proximity to the Walker Lane belt and structures associated with the Nevada National Security Site. Shallow earthquake swarms are recurrent here due to the interplay of extensional stresses and hydrothermal fluid movement within fractured volcanic and sedimentary rocks. Overall, the May 2006 swarm highlights the persistent low-level seismic hazard in this portion of Nevada, where small-magnitude clusters can occur without leading to larger mainshock-aftershock sequences.
References
SeismoSight internal classification data for swarm S20060526.1.
USGS Earthquake Hazards Program regional tectonic summaries for the southern Great Basin.