Seismic Swarm SVS20140706.1 Near West Yellowstone, Montana

Seismic swarm SVS20140706.1 occurred 31 km east-southeast of West Yellowstone, Montana, beginning at 15:41 on 6 July 2014 and concluding at 04:30 on 7 July 2014. Over 12 hours and 49 minutes, the sequence registered 46 earthquakes. Magnitudes ranged from 0.3 to 2.5, with depths primarily between 3 km and 12 km. The largest events reached magnitude 2.5 at depths of 0 km and 9 km, respectively, while several magnitude 2.0 events clustered around 8–10 km depth. Activity was most intense in the first two hours, with events occurring at intervals of seconds to minutes before tapering to isolated occurrences overnight.

This swarm exemplifies typical clustered seismicity in the Yellowstone region. The area lies within the Intermountain Seismic Belt and the margins of the Yellowstone Caldera, an active volcanic system shaped by three major eruptions over the past 2.1 million years. Ongoing crustal deformation, hydrothermal fluid movement, and tectonic stresses from the surrounding Basin and Range province contribute to frequent earthquake swarms. Depths recorded in this event align with shallow crustal processes common beneath the caldera, where brittle failure occurs above deeper ductile zones influenced by magmatic heat.

Historical records since 2000 document 52 swarms in the broader region. Yearly counts include seven swarms each in 2000, 2002, 2006, and 2008; five swarms in both 2013 and 2014; and lower activity in intervening years such as two swarms in 2004, 2007, 2009, and 2010. These episodes reflect persistent volcanic-tectonic interaction rather than isolated mainshock-aftershock sequences.

The 2014 swarm fits established patterns of short-duration, low-magnitude activity that rarely produces felt shaking beyond the immediate vicinity. Monitoring by regional seismic networks continues to track such events to refine understanding of subsurface fluid migration and stress accumulation within the Yellowstone volcanic field.

Data sourced from SeismoSight internal classification. Geological context drawn from U.S. Geological Survey reports on Yellowstone seismicity and caldera dynamics.