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Why the Christchurch earthquake is often used as a case study for what could happen in Salt Lake City

Jerod Johnson, principal with Reaveley Engineers, stands in front of the retrofitted Alfred Emery Building on the University of Utah campus in Salt Lake City on Wednesday, July 3, 2019. Laura Seitz, Deseret News
An unreinforced masonry building located on First Avenue in Salt Lake City is demolished on Wednesday, July 3, 2019. The building recently collapsed as a result of rain pressure on the roof. Laura Seitz, Deseret News
Jerod Johnson, principal with Reaveley Engineers, stands in front of the retrofitted Alfred Emery Building on the University of Utah campus in Salt Lake City on Wednesday, July 3, 2019. Laura Seitz, Deseret News
An unreinforced masonry building located on First Avenue in Salt Lake City is demolished on Wednesday, July 3, 2019. The building recently collapsed as a result of rain pressure on the roof. Laura Seitz, Deseret News
An unreinforced masonry building located on First Avenue in Salt Lake City is demolished on Wednesday, July 3, 2019. The building recently collapsed as a result of rain pressure on the roof. Laura Seitz, Deseret News
An unreinforced masonry building located on First Avenue in Salt Lake City is demolished on Wednesday, July 3, 2019. The building recently collapsed as a result of rain pressure on the roof. Laura Seitz, Deseret News
An unreinforced masonry building located on First Avenue in Salt Lake City is demolished on Wednesday, July 3, 2019. The building recently collapsed as a result of rain pressure on the roof. Laura Seitz, Deseret News

SALT LAKE CITY — On Feb. 22, 2011, at 12:52 p.m., Ann Brower was on a bus on Colombo Street in the downtown area of Christchurch, New Zealand, when the big one hit.

A magnitude 6.3 earthquake shook Christchurch, bringing down brick buildings and taking the lives of 185 people.

"I had been avoiding going to the center," Brower said, "I knew that I wanted to avoid brick buildings in an earthquake zone."

An unreinforced masonry building located on First Avenue in Salt Lake City is demolished on Wednesday, July 3, 2019. The building recently collapsed as a result of rain pressure on the roof.

Laura Seitz, Deseret News

An unreinforced masonry building located on First Avenue in Salt Lake City is demolished on Wednesday, July 3, 2019. The building recently collapsed as a result of rain pressure on the roof.

After a 7.1 magnitude earthquake shook southern California on Friday, many Utahns are likely wondering when the Beehive State might be next.

State and federal officials have warned about the likelihood of this scenario and are particularly concerned about the high number of unreinforced masonry buildings along the Wasatch Front.

As an earthquake survivor and advocate for seismic safety, Brower told her story during a phone interview and warned of the dangers of unreinforced brick buildings.

On the day of the earthquake, she said, she had taken her first trip to the city center since a quake struck the Cantebury region nearly six months earlier.

Though still nervous about the number of brick buildings in the city's center, that morning Brower had thought to herself, "I'll just take the bus and you know, I'll get through the city quicker."

Instead her bus was buried by bricks that fell from a two-story building. There were 13 passengers on the bus; Brower was the sole survivor.

"Brick by brick, pound by pound, ton by ton," she said, "it felt like I could feel bits of me breaking with every brick."

An unreinforced masonry building located on First Avenue in Salt Lake City is demolished on Wednesday, July 3, 2019. The building recently collapsed as a result of rain pressure on the roof.

Laura Seitz, Deseret News

An unreinforced masonry building located on First Avenue in Salt Lake City is demolished on Wednesday, July 3, 2019. The building recently collapsed as a result of rain pressure on the roof.

Sister cities

Because of Utah's high number of unreinforced brick buildings, emergency officials fear the same scenario that Brower lived through when a major quake hits the Wasatch Fault.

Sean McGowan, FEMA's regional earthquake program manager, said the Christchurch earthquake is often used as a case study for what could happen in Salt Lake City.

An unreinforced masonry building located on First Avenue in Salt Lake City is demolished on Wednesday, July 3, 2019. The building recently collapsed as a result of rain pressure on the roof.

Laura Seitz, Deseret News

An unreinforced masonry building located on First Avenue in Salt Lake City is demolished on Wednesday, July 3, 2019. The building recently collapsed as a result of rain pressure on the roof.

Both cities are similar in size and population, and both, he said, are "major hubs, not only (in terms of) population, but for business continuity and connectivity across the region."

"Between the Rockies and the West Coast, you know, it's pretty much you guys and it's similar to Christchurch being on the South Island in New Zealand."

However, McGowan noted, "what really connects (the two cities) and makes them sister cities in my mind" is a high number of unreinforced masonry buildings and a "high seismic hazard."

Jerod Johnson, structural engineer and consultant for the University of Utah's retrofitting efforts, said the materials used in this type of structure "do not have the kind of performance characteristics that enable it to remain intact when you have significant lateral shaking from an earthquake."

He noted that often it doesn't even take a major earthquake to cause significant damage to unreinforced masonry buildings.

In fact, he said, one such structure, located on First Avenue in Salt Lake City, recently collapsed as a result of rain pressure on the roof.

This case, he said, is "a great illustration of the particular vulnerabilities we're dealing with with unreinforced masonry."

The roof on these structures braces the walls and the walls brace the roof, "once the roof began to collapse, (it) was no longer able to brace those walls and walls came down with it."

This type of incident, he said, is the "kind of thing we've seen in the Christchurch earthquake and others, it doesn't take much of a building falling away to be extremely hazardous to anyone."

Both cities, McGowan noted, are near "large active faults" and both are in liquefaction zones.

"It's not a matter of if but (rather) when this earthquake is going to hit (in Utah)," he said.

An unreinforced masonry building located on First Avenue in Salt Lake City is demolished on Wednesday, July 3, 2019. The building recently collapsed as a result of rain pressure on the roof.

Laura Seitz, Deseret News

An unreinforced masonry building located on First Avenue in Salt Lake City is demolished on Wednesday, July 3, 2019. The building recently collapsed as a result of rain pressure on the roof.

The latest report from the Utah Department of Public Safety predicts a 43% likelihood of having at least one magnitude 6.75 earthquake in the next 50 years.

FEMA reports rank Utah sixth in the nation in terms of earthquake risk. This calculation, McGowan said, is based on the population size of Utah's major cities and their proximity to fault lines as well as risk factors such as the number of unreinforced masonry buildings.

A 2008 FEMA study predicted Utah would see more than 6,000 deaths in the case of an earthquake occurring during the daytime. According to the study, 80% of severe casualties would be caused by unreinforced brick buildings.

Brower, an environmental geographer and Fulbright scholar who earned a doctoral in environmental science, policy and management from the University of California, Berkeley, said "you don't need a Ph.D. in engineering to know that brick buildings fall down in earthquakes."

She noted that "it wasn't the earthquake that killed everybody on the bus but me."

'Not my story'

Brower said the impact of the bricks caused the roof of the bus to collapse onto her hip. "It crushed the seat in front of me trapping and breaking my left leg," she said.

"I decided that this was not an acceptable situation, that I was not OK with it. This was not my story," she said. So she screamed and kept screaming until rescuers asked her to "please stop."

An unreinforced masonry building located on First Avenue in Salt Lake City is demolished on Wednesday, July 3, 2019. The building recently collapsed as a result of rain pressure on the roof.

Laura Seitz, Deseret News

An unreinforced masonry building located on First Avenue in Salt Lake City is demolished on Wednesday, July 3, 2019. The building recently collapsed as a result of rain pressure on the roof.

"Somebody crawled in somehow and worked his way into that little pocket between me and the seat in front of me," she said noting that the man, Rob, held her hand and began talking to her as other rescuers worked to dig her out. She was taken to the hospital where she spent the next two month healing from multiple broken bones and injuries.

"I don't think about the earthquake with every step, but my every step is different because of the earthquake," she said. Since then, Brower has become an advocate for brick building safety and seismic preparedness.

"It just felt like what I had to do. I mean, everyone else on the bus died, and the building that crushed us had no restraints on it, whatsoever," she said, noting "there was no attachment between the front of the building and the building itself."

In a paper published by Earthquake Spectra in 2017, Brower detailed her five-year effort lobbying her nation's leaders to adopt retrofitting requirements for unreinforced masonry buildings.

On May 8, 2016, New Zealand's Parliament passed a new building act, known as the Brower Amendment, which imposed stricter requirements for the reinforcement of masonry buildings.

Utahns taking steps

Although in Utah most retrofitting of structures like those is voluntary, state officials, religious leaders and some residents have taken action. And Thursday marks the 25th anniversary of Utah's Seismic Safety Commission, which is tasked with researching and recommending seismic safety policy both to the public and private sector.

Joe Dougherty, spokesman for the Utah Division of Emergency Management, said a number of school districts have taken initiatives to begin partial or full retrofitting of their buildings.

He praised the Salt Lake City School District, which "has either rebuilt or retrofitted every school in the district in the last 20 years."

Johnson noted that the University of Utah has been "very deliberate" about working to retrofit these types of structures.

During a walking tour of the university, he said "virtually every building here on President's Circle, and even buildings adjacent to President's Circle have either been retrofitted or they are currently in process of being retrofitted."

During the 2019 legislative session, Utah lawmakers passed amendments to the state's building code that now require reinforcement of parapets anytime reroofing is done.

The state Capitol was retrofitted in 2005 and The Church of Jesus Christ of Latter-day Saints this year announced a retrofit of its iconic Salt Lake City Temple. Work is scheduled to begin at the end of the year and is expected to last four years.

While many may view the cost of retrofitting their homes as prohibitive, Johnson said this is not necessarily the case.

"There are some real simple things that can be done on homes and residences in particular," he said, noting that "things like creating these anchorages of roofs to walls are big steps in the right direction, and things like bracing nonstructural elements or components."

Johnson said there are a number of steps residents can begin taking to make their homes more safe during an earthquake, adding that they can be done gradually and can be customized to fit the homeowner's budget.

According to Johnson, the cost for minor retrofits on a home can range from a couple hundred to a couple thousand dollars.

He noted that retrofitting during any kind of other renovations to the structure of a home is extremely cost-effective since contractors working on the project will already be exposing the structure of the home.

Full home retrofits, he said, can range from $10,000 to $15,000.

For homeowners wishing to begin retrofitting, Johnson recommended contacting a structural engineer for an initial evaluation. The Utah Seismic Safety Commission has compiled a guide to determining the seismic safety of your home.

Federal predisaster mitigations funds for retrofitting are currently available to many residents who live in Salt Lake proper through the Fix the Bricks program.

The city's high number of unreinforced structures and its large population have made retrofitting these homes a priority, however officials say the program may expand to other areas in the future.

When asked what advice she'd give to Utah residents, Brower said: "Avoid brick buildings like the plague!"

"Don't set up shop in a brick building, and if an earthquake hits when you're in a brick building, stay inside, don't go outside and don't walk past (them)."