An earthquake swarm designated S20240608.2 occurred 13 km northeast of Milford in Beaver County, Utah. The sequence began at 18:39 UTC on 7 June 2024 and concluded at 22:25 UTC on 12 June 2024, spanning 123 hours and 45 minutes. During this period, 152 earthquakes were recorded.
Analysis of the first 100 events reveals predominantly shallow focal depths between 1 and 4 km. Magnitudes ranged from -0.6 to 2.0, with the majority falling between 0.4 and 1.4. The largest event reached magnitude 2.0 on 10 June at 20:57 UTC. Depths clustered tightly around 2 km, consistent with shallow crustal processes. Temporal distribution showed elevated rates during the first 48 hours, followed by a gradual decline, typical of swarm behavior rather than a mainshock-aftershock sequence.
The Milford region lies within the Basin and Range Province of western Utah, characterized by extensional tectonics and active normal faulting. The area is situated near the Mineral Mountains, which host Quaternary volcanic rocks and ongoing geothermal activity. Seismicity here often aligns with mapped faults associated with the Sevier Desert detachment and related structures. Historical records indicate recurrent swarm activity linked to fluid migration or minor strain release along these features.
Since 1 January 2000, twelve earthquake swarms have been documented in the immediate vicinity. These include four swarms in 2020, one in 2021, one in 2022, two in 2023, and four in 2024. Such clustering suggests episodic seismic energy release driven by local geological conditions rather than large-magnitude tectonic events.
The June 2024 swarm produced no reported damage or felt shaking beyond instrumental detection, reflecting the low magnitudes involved. Continued monitoring remains essential given the region's geothermal potential and fault network.