2020 Magna Earthquake Sequence

Updated March 17, 2025

In the five years following the 2020 M5.7 Magna earthquake, UUSS has located over 2,800 aftershocks within 15 km of the mainshock epicenter, with magnitudes ranging -0.6 to 4.6. About 90% of the aftershocks occurred within the first year (March 18, 2020-March 18, 2021). Even though it has been five years, the aftershock sequence is ongoing. In the past 12 months, UUSS has recorded 49 earthquakes within 15 km (9 mi) of the mainshock, with magnitudes ranging from -0.2 to 2.5. This number of earthquakes is significantly above the background seismicity rate of <10 earthquakes a year in the same area. Aftershocks decrease in both number and magnitude as time passes, and even though the sequence is ongoing we don’t necessarily anticipate any more of the larger aftershocks that were felt throughout the Salt Lake Valley in the days and weeks following the 2020 mainshock.

Magna earthquakes March 18, 2020 - Feb 2021 magnitude vs Time plot

UUSS Magna Sequence Catalog

USGS Event Page for the Mainshock

Moment Tensor information:

UUSS Moment Tensor Solutions for the 2020 Magna Sequence

More Information:

Scientific papers related to the 2020 Mw 5.7 Magna, Utah Earthquake

  • Holt, J., K. M. Whidden, K. D. Koper, K. L. Pankow, K. Mayeda, J. C. Pechmann, B. Edwards, R. Gok, and W.R. Walter (2021). Towards robust and routine determination of Mw for small earthquakes: Application to the 2020 Mw 5.7 Magna, Utah, seismic sequence, Seism. Res. Lett., 92(2A), 725-740, https://doi.org/10.1785/0220200320.
  • Baker, B., M. Holt, K. L. Pankow, K. D. Koper, and J. Farrell (2021). Monitoring the 2020 Magna, Utah earthquake sequence with Nodal seismometers and machine learning, Seism. Res. Lett., 92(2A), 787-801, https://doi.org/10.1785/0220200316.
  • Pankow, K. L., J. Rusho, J. C. Pechmann, J. M. Hale, K. Whidden, R. Sumsion, J. Holt, M. Mesimeri, D. Wells, and K. D. Koper (2021). Responding to the Magna, Utah, earthquake sequence during the COVID-19 pandemic shutdown, Seism. Res. Lett., 92(2A), 6-16, https://doi.org/10.1785/0220200265
  • Mesimeri, M., H. Zhang, and K. L. Pankow (2021). Backprojection imaging of the 2020 Mw 5.5 Magna, Utah, earthquake using a local dense strong-motion network, Seism. Res. Lett., 92(2A), 640-646, https://doi.org/10.1785/0220200326.
  • Pang, G., K. D. Koper, M. Mesimeri, K.L. Pankow, B. Baker, J. Farrell, J. Holt, P. Roberson, R. Burlacu, J. C. Pechmann, K. Whidden, M. M. Holt, A. Allam, and C. DuRoss (2020). Seismic Analysis of the 2020 Magna, Utah Earthquake Sequence: Evidence for a Listric Wasatch Fault, Geophys. Res. Lett., 47(18), https://doi.org/10.1029/2020GL089798.
  • Wong, I., Q. Wu, and J. C. Pechmann (2021). The 18 March 2020 M 5.7 Magna, Utah, Earthquake: Strong-Motion Data and Implications for Seismic Hazard in the Salt Lake Valley, Seismol. Res. Lett., 92(2A), 773-786, https://doi.org/10.1785/0220200323.
  • Kleber, E. J., A. P. McKean, A. I. Hiscock, M. D. Hylland, C. L. Hardwick, G. N. McDonald, Z. W. Anderson, S. D. Bowman, G. C. Willis, and B. A. Erickson (2020). Geologic Setting, Ground Effects, and Proposed Structural Model for the 18 March 2020 Mw 5.7 Magna, Utah, Earthquake, Seismol. Res. Lett., 92(2A), 710-724, https://doi.org/10.1785/0220200331.
  • Pollitz, F. F., C. W. Wicks, and J. L. Svarc (2021). Coseismic Fault Slip and Afterslip Associated with the 18 March 2020 M 5.7 Magna, Utah, Earthquake, Seismol. Res. Lett., 92(2A), 741-754, https://doi.org/10.1785/0220200312.
  • Wells, D., A. Lomax, B. Baker, J. Bartley, and K. Pankow (2024). Wasatch Fault Structure from Machine Learning Arrival Times and High-Precision Earthquake Locations, Bull. of Seis. Soc. Am., 114(4), 1902-1919, https://doi.org/10.1785/0120230247.