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SALT LAKE CITY — While folks in Southern California and Nevada continue to feel aftershocks following the two largest earthquakes in the region in nearly 20 years, Utah experts say it’s a reminder that the “big one” can happen at any moment.
“What I can tell you is we’re going to have a 100% (likelihood) of having this event. The question is: Exactly when is it going to happen?” Bob Carey, Utah Emergency Management earthquake program manager, said on KSL Newsradio’s “Dave and Dujanovic” Monday morning. “A lot of the things you’re seeing from Southern California — those are things we would anticipate.”
The earthquakes — a 6.4 magnitude quake on Thursday and another 7.1 magnitude quake on Friday — rattled not just Ridgecrest, California, and the towns near the epicenter, but also Las Vegas and Los Angeles. The Associated Press reported Monday it could take days for “dozens” of homes near Ridgecrest to be assessed.
In the meantime, a Kern County, California, spokesperson told the AP there were about 100 evacuees at a shelter on Sunday and another 43 people camped outside the shelter. Crews were also working to reestablish water for Trona, California, residents Monday, according to the AP.
No fatalities have been reported. Carey said it could have been a different story had the earthquake been centered closer to Los Angeles or Las Vegas. “If it hits a major metropolitan area, then you get a different result,” he said.
While crews work to repair that damage, the U.S. Geological Survey reports there have been more than 100 measurable earthquakes and counting in the area from Sunday through Monday morning. The number continues to grow, but the majority of those quakes are reported with a magnitude between 2.5 and 3.0.
The Utah Department of Public Safety said in a news release the quakes in California are different than what Utah would experience. The Ridgecrest quake sequence are all "strike-slip earthquakes," which means the fault plane is moving horizontally.
What I can tell you is we’re going to have a 100% (likelihood) of having this event. The question is: Exactly when is it going to happen?
–Bob Carey, Utah Emergency Management earthquake program manager
In Utah, most of the faults that generate earthquake move mostly up-down like "normal faults" rather than horizontally, the release said.
Just because the fault zone in California is different than in Utah, it doesn't mean we shouldn't be prepared, especially since much of Utah’s population lies above a fault.
In addition, Carey warned a good amount of houses and structures in Utah are identified as unreinforced masonry buildings, otherwise referred to as URMs. Those are mostly buildings made from brick or block built prior to 1975. They’re more common in Utah’s older cities — like Salt Lake City, Provo or Ogden — where the population has existed much longer than the cities that have rapidly grown since 1975, Carey explained.
“We have a substantial amount of these structures not only in Salt Lake City or Salt Lake County, but across the state,” Carey said. “You’re looking in the greater metropolitan area of about 140,000-plus structures like this. It’s a significant problem in the state.”
Some of these buildings have been seismically retrofitted. For example, the $227 million Utah State Capitol renovation project that was completed in 2008 included work to protect it from earthquakes.
As far as when that major earthquake hits, Carey suggests people memorize techniques from the yearly The Great Utah Shakeout drill. That includes seeking cover; moving away from windows or tall objects that could fall over; moving under a desk, table or other heavy furniture; or moving against a wall in the interior of a building and protecting yourself.
Building collapses are rare. Carey said objects attached to buildings cause a bigger concern.
“Most casualties — this would be on the injury side — come from nonstructural elements of a building. That’d be stuff like signage, stuff outside. A lot of buildings have a facade on them that falls off. You have lighting fixtures.”
As far as when it happens, Carey, much like everyone else in Utah, will just have to wait for what experts believe is inevitable.
More tips for what to do during an earthquake can be found here.
Contributing: Mary Richards, KSL Newsradio; Brian West, Deseret News
