Aftershocks, normal for our area, Utah’s part of the Basin and Range


SALT LAKE CITY (ABC4) – A 2.2 aftershock swayed parts of the Salt Lake Valley Sunday morning. It was one of more than 2500 aftershocks felt since March 18th, 2020, when a 5.5 magnitude earthquake shook Magna and the rest of the valley, causing millions of dollars in damage.

Utah is located in a very active seismic area of the United States, and the entire great basin has many fault areas they even go under the Great Salt Lake.

The trickle of aftershocks is pretty normal.

Although feeling them all the time can put any of us on edge.

Katherine Widden, A Research Scientist with the University of Utah Seismograph Stations, says, “After the 5.5 magnitude quake last year, the ground is now releasing stresses caused by the larger earthquake.

If you think about what has happened below the ground, the rocks shifted. Now, like a pile of dirt above ground or a hole dug in the ground, the area has to settle. Instead of dirt, it’s rocks.

The aftershocks, even though they are on the other side of the valley from where we think the Wasatch Fault is, are still part of the Wasatch Fault Line.

Widden says “It curves across the valley a dip to the west.”

She says, “The chances of another 5.5 earthquakes in the same area are pretty low, and the aftershocks are now at the background area. But, there’s always a chance something big could happen.”

Utah isn’t the site of a major tectonic plate, but it is on the Eastern boundary of a series of intra-plates through Nevada, Idaho, and Utah. It’s called the Basin and Range area.

Construction workers looks at the rubble from a building after an earthquake Wednesday, March 18, 2020, in Salt Lake City. A 5.7-magnitude earthquake has shaken the city and many of its suburbs. The quake sent panicked residents running to the streets, knocked out power to tens of thousands of homes and closed the city’s airport and its light rail system.  (AP Photo/Rick Bowmer)

Our beautiful mountains and valleys are created by a seismic activity called Horst and Graben. It literally means range and valleys, and the effect is created when the Earth’s crust is pulled apart.

Essentially, Western North America is stretching, and that causes the earthquakes in Utah.

Utah has had 8 earthquakes over 5.0 in the last 120 years.

Widden says, “Even though the aftershocks are unnerving, the threat of a bigger earthquake still exists, and you should plan for that, be prepared with a 72-hour kit or even one that lasts a week.

Many people were caught by surprise by last year’s quake, and Widden says you should think about what happens if you are at work and the kids are at school. How will you meet? She said you could learn more at, which is the state’s emergency preparedness website.

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