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KSL TV, File

102 small earthquakes shake Bluffdale area in more than a week, U. seismography reports

By Carter Williams, | Posted - Feb. 21, 2019 at 8:05 p.m.

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BLUFFDALE — It’s been hard for residents in southern Salt Lake County not to notice some of the small earthquakes that have rattled their homes over the past week.

According to the University of Utah Seismograph Stations, there have been 102 small earthquakes in Bluffdale from Feb. 13 to noon Thursday. The largest was a 3.7-magnitude earthquake last Friday.

There were 13 minor earthquakes prior to the 3.7-magnitude quake classified as foreshocks — mild tremors that happen before a bigger earthquake, U. seismograph applications analyst Paul Roberson wrote in a report.

The other 88 minor earthquakes since last Friday’s quake have been classified as aftershocks, Roberson added. The largest of those was a 2.5-magnitude earthquake Wednesday night.

Experts say it’s not uncommon to have a cluster of minor earthquakes in short amount of time, especially since the Wasatch fault zone runs vertically up northern Utah.

“Small earthquakes occur every day in Utah, although most of them are too small or too far from population centers to be felt,” Roberson wrote.

It isn’t immediately clear if the Bluffdale quakes were on that fault line or another unknown fault. However, Roberson added the 3.7-magnitude quake is a reminder that the earthquake threat in Utah is real and a group of minor earthquakes doesn’t lessen the chance of “the big one” coming some day.


“(They) do not relieve enough stress buildup in the earth to reduce the likelihood of a large earthquake,” he wrote.

The report centered around the Bluffdale earthquake swarm and not the 4.0-magnitude earthquake that shook Kanosh, Millard County early Wednesday morning. Three small aftershocks were detected within 45 minutes of the quake, according to the U. Seismograph Stations. A separate 3.3-magnitude earthquake was detected in that area last Saturday.

A small 2.6-magnitude quake rattled northern Utah County on Jan. 26, as well.

Carter Williams

KSL Weather Forecast