ABC4 Utah

March 18 marks 3-year anniversary of Magna earthquake

Ryan Bittan

Cracks and lateral spread features in the Great Salt Lake Marina access road from the 2020 M5.7 Magna, Utah earthquake. Photo courtesy of Utah Geological Survey.

MAGNA, Utah (ABC4) — March 18 marks the three-year anniversary of the Magna earthquake that shook the Salt Lake Valley in 2020.

The 5.7 magnitude quake was the first major earthquake since the city’s founding, and while “moderate” by geological standards, it was Utah’s strongest since a 1992 quake in St. George.

Magna Earthquake Sequence. Photo Courtesy of University of Utah Seismograph Stations
Cracks and lateral spread features in the Great Salt Lake Marina access road from the 2020 M5.7 Magna, Utah earthquake. Photo courtesy of Utah Geological Survey.
Sand boils, liquefaction features caused by ground shaking from the M5.7 Magna earthquake, by the Great Saltair. Photo courtesy of Utah Geological Survey.
Structural damage to a building in downtown Magna caused by the 2020 M5.7 Magna earthquake. The unreinforced masonry, or brick, on the front of the building, failed due to strong ground shaking. Photo courtesy of Utah Geological Survey.
Non-structural damage on the third floor of the Department of Natural Resources building in Salt Lake City. Utah Geological Survey filing cabinets full of paper maps weighing over 100 pounds toppled in a walkway. Photo courtesy of Utah Geological Survey.
1 / 7

The earthquake’s epicenter was reportedly 8 miles below Magna, and people felt it along the Wasatch Front, into Colorado, Wyoming, and Idaho.

“The Magna earthquake sequence is one of the best-recorded earthquake sequences in the entire Basin and Range province,” said Keith Koper, director of University of Utah Seismograph Stations and chair of the Utah Seismic Safety Commission (USSC). “Our network of permanent and temporary seismometers created a wealth of data that led to several research opportunities both published and ongoing. This research has impacted our understanding about faults, earthquakes, and seismic hazard in Utah and the Intermountain West.”

According to the Utah seismograph stations, there were 20 aftershocks in the first hour after the quake.

Additionally, UDOT reported the following day that there had been two “liquefaction” events.

According to the U.S. Geological Survey, liquefaction takes place when “loosely packed, water-logged sediments at or near the ground surface lose their strength in response to strong ground shaking.” Liquefaction that occurs beneath buildings and other structures can reportedly cause major damage during earthquakes.

Back in 2020, liquefaction was discovered near Saltair, as drones discovered “sand boils,” liquefaction features caused by ground shaking.

“When you see the sand boils, and you look, you can see little holes; that’s how the sand kind of just blobs onto the surface,” says Utah Geological Survey Project Geologist, Geologic Hazards Program, Emily Kleber. “We saw a lot of them, but they were in the retaining ponds of the interchange, so not necessarily a natural geologic environment.”

Teams also found cracks and “lateral spread” features in the Great Salt Lake Marina access road.

In the year proceeding the 5.7 magnitude quake, more than 2,500 aftershocks were felt throughout the Salt Lake Valley.

For information on how to be ready for emergencies and disasters, visit Be Ready Utah.