Seismic Swarm S20170607.1: Analysis of Activity Near Carter Springs, Nevada

An earthquake swarm designated S20170607.1 occurred 8 km south-southeast of Carter Springs, Nevada, between 20:39 UTC on 6 June 2017 and 05:33 UTC on 8 June 2017. In 32 hours and 54 minutes, the sequence produced 46 events. Magnitudes ranged from 0.7 to 3.7, with the largest shock occurring at 22:45 UTC on 6 June. Focal depths clustered between 1 km and 15 km, indicating shallow crustal activity typical of the region.

The swarm began with two magnitude-1.4 events within 24 seconds, followed by a rapid increase in rate that peaked with the magnitude-3.7 mainshock and several magnitude-2+ aftershocks within the first four hours. Subsequent activity declined gradually, with isolated events continuing until the sequence ended early on 8 June. Depths remained consistently shallow, consistent with normal-faulting mechanisms prevalent in the Basin and Range province.

Western Nevada lies within the Walker Lane belt, a zone of distributed right-lateral shear accommodating approximately 20 percent of Pacific–North American plate motion. This tectonic setting produces numerous north- to northwest-striking normal and strike-slip faults that generate both isolated earthquakes and episodic swarms. The Carter Springs area sits near the intersection of several such structures, where fluid migration and aseismic slip can trigger clustered seismicity without a single dominant mainshock-aftershock sequence.

Since 1 January 2000, seven swarms have been recorded in the immediate vicinity. Earlier episodes occurred in 2000, 2003, 2005, 2010 (two swarms), 2013, and 2014. These events demonstrate that the region experiences recurrent swarm-type activity, often with comparable magnitude ranges and durations of one to three days.

Such swarms contribute to the broader seismic hazard assessment of the western Great Basin. Although individual events rarely exceed magnitude 4, their occurrence highlights ongoing strain accumulation along faults capable of producing larger earthquakes. Continuous monitoring by regional seismic networks remains essential for distinguishing swarm behavior from foreshock sequences that might precede a damaging mainshock.

References

• U.S. Geological Survey Earthquake Hazards Program, Nevada seismicity reports (usgs.gov)
• Nevada Seismological Laboratory, University of Nevada, Reno, regional tectonic summaries
• Nevada Bureau of Mines and Geology, geologic maps and fault databases