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SALT LAKE CITY — A team of geologists has dug a 150-foot trench by the Salt Lake City International Airport to study the Taylorsville-West Valley City fault, and its rock samples will help scientists forecast when the next major earthquake could erupt along the Wasatch fault.
It's one of about 20 other research trenches being studied along the Wasatch Front to help gauge the havoc a major earthquake could reap in the region, where 80 percent of Utahns live and work.
The state's future could depend on this research, Bob Carey, earthquake program manager for the Utah Division of Emergency Management, said Wednesday.
That's because a 7.0-magnitude earthquake is the worst potential natural disaster facing the region, and it could have cataclysmic impacts on Utah's economy, infrastructure and life.
Carey said Utahns and their leaders need as much information as possible to be fully prepared for what would happen when a major earthquake strikes the Wasatch fault, but researchers only know as much as rock records and hazard prediction models reveal.
Geologic records show a 7.0-magnitude quake occurs along the Salt Lake City segment of the Wasatch fault about every 1,300 to 1,500 years. The last one occurred about 1,400 years ago. It's not a matter of if, but when the next "sleeping giant" will wake, experts say.
"There's a lot we don't know," said Steve Bowman, geologic hazards program manager with the Utah Geological Survey, adding that experts can't predict when the next quake will occur, they can only "forecast" earthquake probability through statistical analysis.
The most current data, paired with hazard prediction models, shows tens of thousands of people will be killed or injured if a 7.0 earthquake were to strike the Salt Lake City segment, Carey said. Buildings and infrastructure would crumble, resulting in at least $33 billion in economic damage.
"Everybody's going to be hurting coming out of this," he said. "That's a big chunk of money. It's going to slow the economy down quite a bit, so that's another reason why we want everyone to take notice because, when this does happen, we'll need to make some tough decisions."
That's why further research is important not only to remind residents and policy makers of the risk, but also to inform how to prepare and react when the "big one" hits, Carey said.
"People need to have the best available data, which then empowers them to make good, solid decisions. … Here's where it all starts," he said, pointing to the trench revealing the Taylorsville-West Valley City fault. "Here we have the raw science. The data that comes out of this helps us understand how frequently earthquakes happen, the types of forces they create, and how the environment will be affected."
This is our game plan. We want to know our opponent, and we want to know what our strengths and weaknesses are and how we're going to attack.
–Leon Berrett, Utah Seismic Safety Commission chairman
Thursday, researchers released a report summarizing hazards and loss estimates that would result if a 7.0-magnitute earthquake were to strike the Salt Lake City segment of the Wasatch fault.
Carey said no information in the report is new, but rather it's a compilation of information to better inform stakeholders — including government and business leaders — about the threat, as well as help emergency officials be best prepared for the catastrophe.
"This is our game plan," said Leon Berrett, chairman of the Utah Seismic Safety Commission. "We want to know our opponent, and we want to know what our strengths and weaknesses are and how we're going to attack."
Berrett said Utahns are at a disadvantage when it comes to earthquake preparedness because earthquakes aren't as common as in other states, like California.
"We get lulled into a false sense of security, and so when we do have a big one, we're less prepared because we're not expecting it," Berrett said. "That's why it's important we have a document like this. It talks about the risk factors, the probability, and what it would do so we can prepare for it."
While outlining the devastation an earthquake would cause in Utah, it also lists recommendations to make Utah more disaster resilient. The recommendations include informing state leaders and public and private stakeholders, encouraging adoption of policies to require seismic retrofits of buildings that pose safety risks, and to fully engage stakeholders in developing disaster resiliency plans.
Carey said there are about 165,000 unreinforced brick buildings in the state, which would cause about 55 percent of deaths in an earthquake.
"Government can take a look at (the report) and decide what plans to start making now so it can do its best job when an earthquake hits," said Joe Dougherty, spokesman for the Utah Division of Emergency Management. "The public is trusting government to be ready to respond; let's not betray that trust."
But Dougherty said responsibility also lies on individuals, since government assistance could take days or weeks to arrive in some circumstances.
"There's only so much government can do to help people prepare for and withstand an earthquake," he said. "We hope people are taking steps to make their emergency plans and get emergency kits together to make sure they're self-reliant in case government can't get there for a week, which is a reality."
For earthquake preparedness tips, checklists, sample plans and other information, visit bereadyutah.gov.