New data suggest need for revision of earthquake hazard models

earthquake hazard models


June 4, 2025
Above: The 1896 Sears mansion in Salt Lake City’s Liberty Wells neighborhood sustained major damage in the Magna Earthquake and was later demolished. Photo credit: Brian Maffly.

 

The sediments underlying the Salt Lake Valley are thicker in places than previously thought, indicating that current seismic hazard models likely underestimate the amount of shaking Utah’s population center could experience in future earthquakes, according to new research led by University of Utah seismologists.

Fan-Chi Lin

Five years ago, the valley trembled during the magnitude 5.7 Magna Earthquake, causing millions in damage to dozens of masonry structures in Salt Lake City and the town of Magna, a few miles to the west. Utah’s urban centers, such as Ogden, Salt Lake City and Provo, lying along the Wasatch Front, remain at risk of future seismic events. The last major earthquake exceeding magnitude 7 to hit the Wasatch Front occurred between 1,200 and 1,300 years ago. With an average recurrence interval of 900 to 1,300 years, Salt Lake City’s geologic clock could be close to striking midnight once again.

In the new study, U researchers utilized seismic data to present a refined three-dimensional seismic velocity model—an essential tool for mapping the geologic structure of the Wasatch Front and identifying seismic hazard sites.

“For this particular study, we are trying to understand the sedimentary structure within the Salt Lake area and how that might differ from previous results,” said study leader Fan-Chi Lin, an associate professor of geology and geophysics. “One of the biggest questions we had was why our observations didn’t agree with previous studies.”

The Wasatch Front community velocity model is currently the leading reference for assessing future seismic activity. However, it has been largely informed by borehole drilling and gravity data—useful indicators, but ones that come with limitations such as private land restrictions, inconsistent documentation and limited sampling scope.

To overcome these constraints, an extensive network of seismic data probes and geophone arrays was deployed across the Salt Lake Valley—even in the backyards of private residences. Many were deployed in the month following the Magna quake in the spring of 2020 to take advantage of a steady parade of aftershocks.

“This community is incredibly supportive and happy to help. I want to emphasize that none of this would have been possible without community support, the Utah Geological Survey and the many students in our department who helped deploy hundreds of stations,” Lin said.

For this study, the research team analyzed seismic waves from only distant earthquakes, using interferometry analysis—comparing measurements of the same signal from two different stations—and conversion phase analysis—comparing the incident P-wave and the S-wave converted at the base of the sediment. This analysis gleaned insights into the subsurface structure of the Salt Lake Valley, which was once the bed of ancient Lake Bonneville that covered northern Utah as recently as 14,000 years ago.

The goal wasn’t to predict strong earthquakes but to predict the severity of ground motion they could produce. The team was also pursuing academic questions.

“We are interested to understand how the tectonic forces or tectonic movements form the basin itself,” Lin said. “Why there’s a basin here? What controls the depth of the basin?”

by Ethan Hood
Read the entire article on @ The U.

Humans of the U: Sydney Brooksby

Humans of the U: Sydney Brooksby


May 27, 2025
Above: Sydney Brooksby in competition on archery range. Credit: USA Archery

People only get brave when they have nothing to lose. Be brave anyway.

As I entered college, I was in renal failure and had two choices: Return home and enjoy the rest of my declining life, or make one last effort to achieve my childhood dream. I chose the latter. I received an auto renal kidney transplant, picked up my textbook and asked myself this question, ‘How far are you willing to go?’ I’m willing to go farther than anyone has before me.

My disease drove me to pursue a degree in biology. It’s been incredible to be in a position, as a student, where I can exercise my own ambition by drafting a gene-editing research proposal to mitigate the effects of my own disease, Turner Syndrome (TS). I was born with Mosaic TS, a genetic mutation that causes one of a female’s X chromosomes to be incomplete or completely missing.

Throughout my undergraduate experience, eliminating the uncertainty of my condition was aided through studying genomics. I was able to take authority over my own health care. It made every surgery, procedure and supplemental diagnosis easier to comprehend and overcome.

All the while I continued competing in archery as a member of the U.S.A. RED Team with a goal of qualifying for the 2028 Los Angeles Olympics.

My favorite biology course has been Gene Expression (BIOL 5120), taught by Prof. Michael Werner of the School of Biological Sciences. In this class, I learned how to translate my excitement for genomics and genetic engineering into a research proposal. With chromosomal mutations like Turner Syndrome, recovering lost genetic information is at the core of any real solution. My proposal outlined how gene-editing technologies—such as CRISPR-Cas9homology-directed repair (HDR) and mRNA delivery—could be used to ‘copy and paste’ missing genetic content onto a fragmented X chromosome. I focussed on the SHOXa gene with the goal of recovering genetic function in female hormone secretion and physical growth of patients with Turner Syndrome. Understanding the science, specifically gene-editing technologies, offers real hope for addressing TS and other genetic diseases.

I’ve been very blessed with my medical condition, and also with the knowledge I’ve gained during my undergraduate studies that allows me to theorize actionable solutions. I hope to one day attend medical school and specialize in hepatobiliary (kidney/liver) transplant surgery with a supplemental focus in chromosomal abnormalities!

What I would say to my freshman self and undergraduates just beginning their journey at the U, ‘People only get brave when they have nothing to lose. Be brave anyway.’”

by Sydney Brooksby

Sydney is majoring in biology with an emphasis in genomics/genetics, and minoring in medical humanities. U.S.A. RED Team member (archery) and 2028 Los Angeles Olympics hopeful.

This story was developed and edited by Tanya Vickers, School of Biological Sciences
and originally appeared in @The U. 

STEM Safety Day 2025 Priority Registration

Safety Day Priority Registration

Space is limited for many sessions.  Those who complete priority registration below will have early access to full registration in late summer 2025 when the detailed program is published.

2025 Safety Day Priority Registration
Name
Name
First
Last