What’s the value of a few seconds? A lot when an earthquake is coming.

This story is part of The Salt Lake Tribune’s ongoing commitment to identify solutions to Utah’s biggest challenges through the work of the Innovation Lab.

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What would you do if you had 10 seconds warning ahead of a major earthquake? How about two?

The Utah Geological Survey is investigating rollout of an earthquake early-warning system like that already in use on the West Coast.

“Our goal is to get tens of seconds,” UGS Director Bill Keach told lawmakers at a Natural Resources, Agriculture and Environment Interim Committee meeting on Oct. 11.

The “Shake Alert” system, which is operated by the U.S. Geological Survey, has been delivering warnings in California since 2019 and in Oregon and Washington since 2021.

The system relies on the detection of “primary seismic waves,” called P waves, that propagate first from the epicenter of a quake. Such waves move fast but do not carry much energy. They are then followed by “shear waves,” also called S waves, that produce the ground shaking and liquefaction that can cause earthquake damage.

In general, S waves move at about 60% the speed of P waves — and that difference could be lifesaving.

30 seconds or no seconds

In examples presented to legislators, Keach explained that locations farther from a quake’s epicenter would get the most warning. If a major (magnitude 7) quake occurred in Brigham City, for instance, Ogden would get one second of warning, Salt Lake City would get 16 seconds, and Provo would get 33 seconds.

If the earthquake occurred in Magna, as a 5.7 quake did in March 2020, Salt Lake City would get two seconds of warning, Ogden would get seven seconds, and Provo would get 17 seconds.

And Magna? They would get no advance warning of a quake, because the P waves below them would be barely ahead of the S waves.

“There is what they call the no-alert zone,” Keach said.

So what good is a few seconds? It might be time enough to get out of an old brick building. Unreinforced masonry structures, which includes about 140,000 Utah homes, are at high risk of failing in a major earthquake. Or it might be enough time to at least stand in a doorway where the chances of survival are a little better.

But the real advantage is in developing automated responses. Keach gave the example of fire station doors that would open at the warning so fire trucks can leave the stations even if the quake makes the doors inoperable.

Other examples include gas, power and water lines that could shut down, limiting the danger from damaged lines. And hospitals could switch to generator power before the grid goes down.

“You can slow down a train on FrontRunner before it goes off the tracks,” said Keach.

Major Wasatch Front earthquake is likely

The report estimated the cost of implementing Shake Alert in northern Utah, which already has a seismic monitoring network, would be $4.8 million, and that includes adding 80 seismic monitoring stations.

Ongoing costs would total $960,000, including hiring five full-time employees. Taking Shake Alert statewide would likely come later and cost another $7 million, Keach said, because parts of rural Utah have little or no seismic monitoring.

Shake Alert is the result of more than $200 million in research and development over the past 15 years, he added.

“We’re going to leverage all they did and bring it here for $5 million,” he said, noting that the Federal Emergency Management Agency has estimated that the short-term economic loss from a magnitude 7 quake along the Wasatch Front would be $80 billion.

And a major quake along the Wasatch Front isn’t just possible. It’s expected. In 2016, the Utah Geological Survey’s Working Group on Earthquake Probabilities reported that there is a 57% chance of a magnitude 6 quake, and a 43% chance of a 6.75 magnitude quake, in the next 40 years.

As part of the research, the Utah Division of Emergency Management surveyed people at businesses, utilities and government entities to see if they had automated systems that could accept a shut-down signal from Shake Alert, and 73% said they didn’t. So there would be additional costs to maximize the warning system’s potential.

Utah, like California, gets hundreds of earthquakes every year, though the vast majority are small and cause no damage. Shake Alert is designed to only warn of earthquakes over 4.5 magnitude.

Alerts by phone

How would Utahns get a warning? By phone app, of course. The University of California, Berkeley has developed the “MyShake” app, which gives warnings in the three West Coast states. Both iPhone and Android versions are available.

Angie Lux, project scientist for Earthquake Early Warning at the Berkeley Seismological Laboratory, said in a phone interview that when a MyShake alert is sent, it will include the estimated location and magnitude of a quake, but those early estimates can change.

On Oct. 18, for instance, people in the Sacramento area received a Shake Alert warning for a quake near Isleton that was originally thought to be 5.7 magnitude. But after the alert was sent, it was found to be a 4.2 quake.

“There’s a tradeoff in how accurate we can be about the earthquake magnitude, and how quickly we can alert people,” Morgan Page, a research geophysicist at the U.S. Geological Survey in Pasadena, told the San Jose Mercury News. “We really feel it’s more important to alert people really quickly that there might be shaking, and occasionally overestimate it, than to not give people any warning at all, given that it takes a long time to estimate magnitude precisely.”

Rolling out Shake Alert in Utah would require legislative approval. Lawmakers did not ask any questions at the committee presentation this month, but Rep. Gay Lynn Bennion, D-Cottonwood Heights, offered her “full-throated endorsement.”

In an email, Keach said there is no bill sponsor yet, but “several legislators reached out afterwards expressing interest to help.” His office has also provided the costs to Gov. Spencer Cox’s office to consider for the governor’s budget.