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Westminster College’s oldest neighbor: the Wasatch fault

On this episode of The Forum podcast, Production Manager Ella Viesturs talks with Nick Pollock, assistant professor of Honors and geology at Westminster College, about the Wasatch fault, visibly identifiable as 1300 East, Westminster’s neighborhood street. Pollock answers questions and concerns about the Wasatch fault line. 

Westminster College sits no more than 100 yards from the Wasatch Fault, meaning  students study and Salt Lake City residents live in a significant geologically active zone, according to Nick Pollock, assistant professor of Honors and geology. 

Pollock started as an assistant professor at Westminster in Fall 2020 after completing his Ph.D. in geosciences, specifically researching Mount St. Helens at Boise State University in Boise, Idaho.

Pollock said the rest of the Westminster community shares a neighborhood with one of the most seismically active faults in North America.

A man sitting at a desk illustrates a fault line on a whiteboard. In geology, a fault line defines a crack in the Earth’s crust wherein eachside of the crack moves away from one another.
Nick Pollock, assistant professor of Honors and geology at Westminster College, illustrates the Wasatch fault’s relation to the Salt Lake Valley and the Wasatch Mountains Nov. 10. The Wasatch fault is a normal fault which defines a crack in the Earth’s crust that experiences vertical motion; rock on one side moves upward and downward on the other, according to Pollock. The Salt Lake Valley floor to the west of the Wasatch fault moves downward, while the Wasatch Range to its east moves upward, according to Pollock.  Photo courtesy of Ella Viesturs. Image description: A man wearing a mask and a plaid shirt is sitting at a desk using a whiteboard and a black pen to illustrate a fault line. In geology, a fault line defines a crack in the Earth’s crust wherein eachside of the crack moves away from one another. In his drawing, one side of the fault line is moving upwards (The Wasatch Mountains), and the other side (The Salt Lake Valley) is moving downwards. Fault lines are what create mountain ranges and valley floors. 

90% of the Utah population lives in active earthquake zones, according to The Great Utah Shakeout.

The Wasatch fault is a “normal” fault. In geology, a fault line defines a crack in the Earth’s crust and the type of fault is determined by how the rock on either side moves in relation to the fault, according to Pollock. 

“So in our case with the Wasatch fault, the crust here is being stretched apart almost like an accordion. […] When you drive up I-15 and you’re following this long stretch of mountains that you can see off to the East, that is evidence of the fault,” Pollock said. 

According to Pollock, the Wasatch Mountains have been pushed up over a long period of time, and the valley is progressively dropping down. Pollock said the mountain range is a result of that very slow movement along the fault. 

There is a 43% probability that the Wasatch fault zone will experience at least one magnitude 6.75 quake within the next 50 years, according to Earthquakes.Utah.gov.

A birds eye view photograph of Salt Lake City shows Westminster College, the Great Salt Lake and the Wasatch fault indicated by a white line.
The Wasatch fault, which runs just east of the Westminster College campus, is one of the most seismically active faults in North America, according to Nick Pollock, assistant professor of Honors and geology. The fault is about 220 miles long, starting in Malad City, Idaho and ending in Fayette, Utah, according to the United State Geological Survey. Graphic courtesy of Ella Viesturs. Image description: A birds eye view of Salt Lake City shows Westminster College to the west of the Wasatch fault and to the east of the Great Salt Lake. The Wasatch fault, indicated by a white line, runs vertically through the entire photo, just left of center.

Magnitude measures the shaking caused by an earthquake. The scale is logarithmic, so with each increment of one added to the magnitude of an earthquake, the shaking increases by 10, according to Science.org’s webpage.

For example, a magnitude six earthquake shakes 10 times as hard as a magnitude five earthquake, and 20 times as hard as a magnitude four, according to Science.org’s webpage

On March 18, 2020, Salt Lake City and greater Utah experienced the Magna earthquake, a magnitude 5.7 quake with an epicenter 6 km north-northeast of Magna, Utah. This relatively small shake did not relieve enough stress to reduce the likelihood of a magnitude 7-7.5 earthquake, according to the University of Utah Seismograph Stations

While the “Big One” earthquake is inevitable, the best thing Westminster students and Salt Lake residents can do to ease their minds is to become educated on earthquake preparedness, according to Pollock. 

A man sitting at a desk illustrates the intersection of two fault lines under a city using a whiteboard.
Nick Pollock, assistant professor of Honors and geology at Westminster College, illustrates the intersection of the Magna and Wasatch Faults, which is nearly directly below Salt Lake City, home to Westminster College, Nov. 10. On March 18, 2020 there was a 5.7 magnitude earthquake along the Magna Fault. Its epicenter was 6 km north-northeast of Magna, Utah, according to the University of Utah Seismograph Stations. Photo courtesy of Ella Viesturs. Image description: A man wearing a mask and a plaid shirt is sitting at a desk using a whiteboard and a black pen to illustrate where the eastern Wasatch fault and the western Magna fault intersect in the Earth’s crust. Both faults run directly beneath Salt Lake City.

Every year, the United State Geological Survey hosts the Great Shakeout Drill, an international earthquake drill where people practice drop, cover and hold on. The international drill takes place Oct. 21 and the Great Utah Shakeout occurs April 21, 2021, according to the Great Shakeout webpage.

There is no avoiding a big earthquake in the future. Pollock said that earthquake preparedness is the best way for people to feel like they can manage the idea of a big shake.

“I think that it’s important […] to be educated about [earthquakes’], that’s kind of step one: understanding that there is a risk of this happening. [By] practicing these earthquake drills and just kind of mentally understanding that this risk exists, we can be better prepared in the event of an earthquake,” said Pollock.

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