That’s because sediments in some areas under the valley are thicker than expected, researchers said in a news release — and thicker sediments can lead to stronger shaking during an earthquake.
“In a basin, seismic shaking is amplified. It’s very important to understand the thickness and rigidity of sediment to better assess potential shaking. The sediment is thicker than previously thought — especially in the heavily populated area south of Salt Lake City,” study leader Fan-Chi Lin, an associate professor of geology and geophysics at the U. said in the release.
The state is still rebuilding infrastructure shaken up by the 5.7 magnitude Magna earthquake that happened in 2020. However, often referred to as “the big one,” a future earthquake of 6.75 or greater magnitude is highly probable at the Wasatch Front in the next 50 years, according to Envision Utah.
With about 80% of the state’s population living in the area, experts estimate that could be an exceptionally devastating event.
“Our findings reinforce the idea that a hazard exists in the valley and that shaking could be stronger than expected. Many houses in Salt Lake are unreinforced masonry and could be vulnerable in a big quake,” Lin said. “Buildings should be reinforced, and people should be prepared.”
After installing an extensive network of seismic data sensors along the valley after the spring of 2020 and analyzing seismic waves from distant earthquakes, Lin’s team created a revised and refined three-dimensional seismic velocity model to map the Wasatch Front’s geologic structure and identify earthquake hazard sites.
That model allowed the researchers to find thicker sediment deposits than previously estimated, and can provide answers when preparing for “the big one.”
“If we know the subsurface structure very well, then we can predict how strong the ground motion will be when the big earthquake happens,” Lin said. “And that will allow us to collaborate with the engineers to determine which buildings are potentially hazardous when the big earthquake hits.”
This story was originally published at UtahNewsDispatch.com.
