Three of these intersect the Wasatch Fault zone and the fourth is in an area of risk for landslides. Why should we be concerned along the Wasatch Front? Plenty of reasons.Ī 2022 report by the Utah Seismic Safety Commission placed a good deal of attention on those unreinforced masonry buildings, but it also sounded warnings about four major aqueducts along the Wasatch Front that provide water to more than 2 million people. In Utah, ancient volcanic ash has turned to clay in many areas, and water makes that clay swell. Hillsides are under various levels of stress depending on the angle of the slope and the type of soils they contain. That hillside was a “large old mass of rocks that were just on the brink of exceeding equilibrium,” Ben Erickson, senior geologist for the Utah Geological Survey, told me. 3 years after Magna earthquake, here’s how Utah’s preparing for an even bigger oneĪ report at the time said this was the farthest recorded distance “for a coherent landslide of this type” from such an earthquake.
It ended up causing a powerful landslide in Springdale, about 27 miles away, that destroyed three homes. Oddly, the force of that quake pushed itself away from St. No one knows the answer to that, but history gives us lots of clues about the dangers. How many houses would slide if the big one, a magnitude 7.0 earthquake or higher, hit? Lawmakers have even done a little to deal with it. Plenty of people and commissions have been willing to point out the problem. The two houses in Draper that slid into a ravine last month were just the latest examples. You don’t have to dig too hard in the archives to find all kinds of examples of hillsides collapsing around the state, taking houses with them. Utah’s majestic mountains have a way of shaking themselves off from time to time, like irritated sleeping giants.Īctually, that’s not a news flash. In the 5.7-magnitude quake that hit the Salt Lake Valley in 2020, falling bricks from these buildings posed the biggest danger.īut now, it’s clear that landslides ought to be a big concern, as well. When the ground shakes, these tend to crumble, injuring anyone beneath.
When it comes to earthquake preparedness, a lot of people (myself included) have focused on the need to shore up the approximately 140,000 aging homes and buildings along the Wasatch Front made of unreinforced masonry.
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