Seismic Swarm S20150907.1 Near Beatty, Nevada
An earthquake swarm designated S20150907.1 occurred 45 km east-southeast of Beatty, Nevada, from 07:08 on 6 September 2015 to 17:59 on 7 September 2015. The sequence lasted 34 hours and 51 minutes and included 26 events. Magnitudes ranged from -0.7 to 0.7, with the majority of events below magnitude 0.0. Focal depths clustered between 2 km and 8 km, indicating shallow crustal activity typical of the region.
The swarm began with a magnitude -0.2 event at 3 km depth. Subsequent events maintained low magnitudes and similar shallow depths, with several occurring in close temporal succession during the evening of 6 September and early morning of 7 September. Activity tapered after 05:00 on 7 September, concluding with a final magnitude -0.1 event at 6 km depth.
This swarm forms part of a documented pattern in the area. Since 1 January 2000, 36 swarms have been recorded near Beatty. Yearly counts include five in 2000, seven in 2002, two in 2003, two in 2005, one in 2006, two in 2007, seven in 2008, four in 2009, three in 2010, one in 2012, one in 2014, and one in 2015. These recurrent swarms reflect ongoing tectonic adjustment rather than isolated mainshock-aftershock sequences.
The Beatty region lies within the Basin and Range province of southern Nevada, characterized by extensional tectonics driven by normal faulting. The area experiences distributed crustal stretching, producing frequent small-magnitude earthquakes at shallow depths. Proximity to the Walker Lane shear zone and volcanic features such as the Timber Mountain caldera further influences local seismicity. Historical monitoring indicates that swarms in this setting typically involve low-energy releases along minor fault segments without producing surface rupture.
No events in S20150907.1 exceeded magnitude 1.0, consistent with background microseismicity levels documented across the central Basin and Range. Depths between 0 km and 8 km align with the brittle upper crust where strain accumulates and releases episodically.
References
- SeismoSight internal swarm classification S20150907.1
- U.S. Geological Survey Earthquake Catalog (historical Nevada seismicity)
- Nevada Bureau of Mines and Geology regional tectonic summaries