Unveiling the West’s Seismicity: Insights from Central Utah’s Earthquake ‘Swarms’

Central Utah’s seismic activity has been characterized by clusters of earthquakes called “swarms,” which differ from aftershocks following major earthquakes. These swarms consist of many small, often undetectable earthquakes, concentrated in a specific region over a short period. The University of Utah manages a seismic network that has recorded numerous earthquake swarms in central Utah over the past four decades.

A recent study by Utah seismologists aimed to understand the significance of these swarms in a geologically complex region known for its geothermal activity and volcanic eruptions. The researchers analyzed decades of seismic data and found that 80% of the earthquake sequences in central Utah are swarms, demonstrating their prevalence and heterogeneity across different locations. The study, published in the journal Geochemistry, Geophysics, Geosystems, sheds light on the interactions between regional tectonics, local structures, and hydrothermal systems.

Exploring a Geothermal Hot Spot

The research area around Milford, Utah, known as FORGE (Frontier Observatory for Research in Geothermal Energy), is rich in geothermal activity. This region, which includes Beaver, Iron, Sevier, and Paiute counties, is home to three geothermal power plants and several towns. The scientists hypothesize that these earthquake swarms are triggered by hot water, driven by geothermal activity, flowing through fractures in the Earth’s crust.

The study examined over 2,300 earthquakes, primarily ranging from magnitude 1 to 3, with the largest being a magnitude 5.1 earthquake in 1989. The researchers identified 40 qualified swarms and emphasized the importance of studying these smaller quakes despite their challenges. The analysis revealed that earthquake activity in Utah extends beyond the well-known Wasatch Front, underscoring the need to better understand seismicity across the state.

Implications and Future Research

The findings of this study provide valuable insights into the behavior of earthquake swarms in central Utah. By examining these swarms, scientists can gain a better understanding of the activated structures in the area. The study also highlights the rapid and recurring nature of seismic activity, with clusters of earthquakes occurring within a few hours and then pausing. This knowledge can contribute to improved earthquake monitoring and hazard assessments in the region.

Further research is needed to fully comprehend the complex interactions between regional tectonics, local structures, and hydrothermal systems in central Utah. This understanding will help scientists and seismologists better predict and mitigate earthquake hazards, not only in central Utah but also in other geologically active regions.