A day after the Wasatch Front’s biggest earthquake on record, crews responded to countless sites around Salt Lake County, fixing and documenting damage, even as substantial aftershocks continued rolling from Magna, near the epicenter of Wednesday’s magnitude 5.7 temblor.
Officials, meanwhile, said the quake should serve as a wake-up call for Utahns to prepare for the much more serious shaker that remains a possibility for northern Utah, which is riven with faults that are expected to rupture in the coming decades.
The quake struck as Utahns were rising to another day of disruption from the COVID-19 pandemic that has shuttered schools, churches and most places where people gather to reduce the spread of the coronavirus.
Bob Carey, response and recovery bureau chief for the Utah Division of Emergency Management, likened Wednesday’s quake to a “walk in the park” compared with what could be in store. Still, the temblor has damaged many older masonry structures that might have to be rebuilt. Carey said the quake offered a kind of “natural urban renewal,” but, more important, it should remind residents to prepare for a bigger strike.
“If you count on government to help you with this event, you’re making a mistake. You’ve got to be on your own for a couple of weeks,” Carey said. “This is the earthquake that I’ve always wanted to have happen. I know that sounds nutty, but it lets us understand that we can actually have this.”
Among Salt Lake City’s historic houses of worship, the Cathedral Church of St. Mark, 231 E. 100 South, was probably the hardest hit, forcing the Episcopal Diocese of Utah to keep people out until it can be deemed safe.
The building, dating to 1870, sustained interior damage to the west transept of the nave. The shaking also shifted some organ pipes and cracked walls where they meet the roof, according to the Rev. Tyler Doherty, dean of the cathedral.
“We are not sure it’s structurally sound,” Doherty said. “We are waiting for an engineer to go through [it]."
The earthquake cut electricity to some people on the Wasatch Front. At the outage’s peak, more than 75,000 homes and businesses were without it, said Rocky Mountain Power spokesman Spencer Hall.
Crews worked through the day and electricity was restored to all but a handful of customers by 10:30 p.m. Wednesday, Hall said. The utility decided to transfer customer service calls from a call center in West Valley City to a backup site in Portland, Ore.
“This allowed the company to respond to the high call volume from customers," Hall wrote in an email, “despite evacuating our Utah call center.”
1,768 emergency calls
Don Porter, manager of media relations for Dominion Energy, said the utility typically receives 68 leak calls a day within its service area of southwest Wyoming, across Utah and to Preston, Idaho.
On Wednesday, Dominion received 1,768 emergency calls.
“Our system came through pretty much with flying colors,” Porter said. There were leaks at homes and businesses, but no underground pipes cracked or burst.
As of Thursday afternoon, Porter said, the only outstanding issue for Dominion was the mobile home park on 7200 West in West Valley City, where officials condemned 49 homes. Porter said Dominion had to shut off gas to the entire park to sever connections to the impacted homes. The utility was trying to finish that work Thursday and restore service to the remaining customers.
Sam Johnson, a spokesman for West Valley City’s municipal government, said people who had lived in those 49 condemned units are the only city residents who have been displaced.
“We have gone out and done inspections on other homes,” Johnson wrote in an email, “but there have not been any cases to the extent of residents not being able to stay in their homes.”
Kennecott Utah Copper halted operations Wednesday to inspect for any earthquake damage and to clean up a tank of hydrochloric acid that began leaking.
Kyle Bennett, a spokesman for Kennecott Utah Copper, said Thursday that operations were resuming as areas or components passed inspection.
“Full inspections are continuing to be carried out," Bennett texted, “to ensure it is safe to restart each part of the business.”
The Department of Environmental Quality checked drinking water and wastewater systems and found few lasting problems, according to spokesman Jared Mendenhall.
“There were a few line breaks. By [Wednesday] evening, there were no interruptions in drinking water service,” Mendenhall said. “One wastewater treatment plant had a power outage, but backup generators kept things flowing. We are continuing to monitor for any threats to the environment.”
How many aftershocks so far?
By 4 p.m. Thursday, more than 160 aftershocks had been recorded, 99 of which exceeded magnitude 2, which could have been felt at the epicenter northeast of Magna. According to the U. Seismograph Stations, 31 were magnitude 3 to 4, while three exceeded magnitude 4 and could be felt in Salt Lake City.
Thursday’s biggest aftershock, coming at 6:44 a.m, measured magnitude 3.2.
In coordination with University of Utah scientists, the Utah Geological Survey is installing mobile seismographic instruments near the fault that ruptured Wednesday and will keep moving for the next several days, if not weeks. They hope to learn more about the fault, which is not expressed on the surface, but connected to the better known Wasatch fault zone, according to Steve Bowman, the survey’s geological hazards director.
Wednesday’s quakes occurred in roughly the same location as a 1962 sequence, the largest registering a magnitude 5.2.
Survey crews were out Thursday examining the geological effects, such as a phenomenon called liquefaction, in which jiggling sediments mix with groundwater and push through the surface. Cracks propagated all over the Great Salt Lake Marina’s paved parking lot.
“Water can shoot out of the ground, sand volcanoes pop up. They are a few feet in diameter, four to six inches high. They help show the effects of the earthquake,” Bowman said. “We can see how well infrastructure has performed. That data is helpful. That’s how building codes are improved.”
The survey has activated an online clearinghouse for data related to the quake.
“That’s going to be a website to which you can contribute photographs and observations,” Carey said, “so we can memorialize this event and use it to better understand future earthquakes."
Much of the Salt Lake City metro area is built atop sediments from an ancient lakebed, which may have contributed to the severity of the shaking felt Wednesday.
“The ground motion will get amplified. The energy, in a sense, will get trapped in the basin and act like a bowl of jelly, and it’ll just keep keep shaking,” U. seismologist Keith Koper said. “People that were in tall buildings downtown, they might have actually felt significant swaying and shaking from this earthquake. A lot of damage tends to be in basins because of this sort of amplification effect.”
What homeowners should do
The damage so far seems typical for this type and magnitude of earthquake, according to Utah State University engineering professor Marv Halling, an expert in structural engineering. Damage could be seen on many unreinforced masonry homes in Salt Lake City’s older neighborhoods.
“If there is a larger event, some of these more vulnerable buildings could sustain [greater] damage,” Halling said. He recommended owners of homes showing cracks to get them checked by an engineer to ensure they are structurally sound.
Newer structures fared better because they were built to tougher standards.
“The way the building codes developed over the years, every time there are additional earthquakes around the world, more things are learned about structural behavior,” he said. “If you are a concerned homeowner, there are several things you can do to bring those homes up to code or at least improve their performance, like tying in a building to its foundations. A lot of older homes can slide off their foundations. It is not life-threatening, but it can be a huge economic hit.”
Greg Schulz, administrator of the Magna Metro Township, said crews were still inspecting buildings on Main Street at 8:30 p.m. and likely wouldn’t finish Thursday night. They were expected to return early Friday to continue the assessment.
He added that all residents should inspect their own homes or businesses for damage and document it. Those who find damage can report it online at https://arcg.is/1uGXee or by calling 385-468-6723 between 8 a.m. and 5 p.m. After hours, call 385-468-6690.
Utah Department of Transportation spokesman John Gleason said the agency had inspected about 450 of the 625 bridges in the quake zone as of Thursday afternoon.
“Generally, what they’re looking for in these bridge inspections is cracks,” Gleason said, “[and] that the joints are functioning properly, that the beams are functioning properly."
The only bridge that has been closed is the westbound on-ramp to Interstate 215 at Union Park Avenue in Midvale. Gleason said engineers will take a closer look at that bridge and begin repairs after the other bridge inspections. UDOT engineers identified 13 other bridges that suffered minor, mostly cosmetic damage, Gleason said. They are not considered a safety hazard.
A few blocks from downtown Salt Lake City’s St. Mark’s cathedral, St. Paul’s Episcopal, First Presbyterian and First United Methodist churches suffered some apparent damage, but it was too early to say how significant.
“Nothing catastrophic, thank goodness,” said the Rev. Elizabeth McVicker, pastor for the Methodist church built in 1906 and renovated four years ago. It showcases one of the oldest organs in the West in its sanctuary, which has served as a busy community venue. The space now shows severe cracking, perhaps a testament to the need for a seismic upgrade.
For Utah’s predominant religion, The Church of Jesus Christ of Latter-day Saints, whose campus rests in the heart of Salt Lake City, contractors and consultants found no structural damage to any of those buildings in and around Temple Square.
“All buildings at church headquarters have reopened," the faith said in a news release Thursday, "although they remain closed to the public due to the COVID-19 outbreak.”
But the denomination hardly escaped unscathed. A dozen meetinghouses, mostly located in the Magna area, appear to have sustained structural damage and will require further assessment.
Structural damage also was evident at the church’s Humanitarian Center and Deseret Manufacturing on Salt Lake City’s west side. Beehive Clothing had some interior damage, too. Those facilities remained closed.
And, as has been widely reported and photographed, the faith’s iconic Salt Lake Temple, which happened to be closed for renovation and a seismic retrofit, also sustained minor damage. The six-spired edifice had some smaller stones displaced and its Moroni statue on top dropped its famous trumpet. But the golden angel still greeted the sunrise Thursday as it has done for more than a century.
— Salt Lake Tribune reporter Paighten Harkins contributed to this report.