Xie Hu, Xue Liang, Roland Bürgmann, Yuning Fu, Teng Wang

The March 18, 2020 M5.7 Magna earthquake awakened people from decades of seismic quiescence in Salt Lake City, Utah. The event occurred just east of a mine tailings impoundment that receives ~60 million tons/yr of ore waste products since the early 1900s. Here we investigate elastic loading effects due to the anthropogenic mass transfer and various natural hydrological loads. We note a possible spatial correlation between earthquake clusters and Coulomb stress changes of tens of kPa due to the tailings loads. In contrast, long-term and seasonal stress changes from hydrological loads are only several kPa. A lack of statistically significant seasonality in seismicity suggests a weak control by cyclic hydrological loads. Anthropogenic loading rates of ~1 kPa/yr at seismogenic depths during recent decades may accelerate or decelerate event occurrences by several hundreds of years, mainly depending on the encompassing fault geometries.