SALT LAKE CITY — Utah residents have been warned for decades about the risk of the “big one” destroying homes, killing thousands and putting the Wasatch Front in a catastrophic mess.

Yet in the aftermath of the moderate magnitude 5.7 earthquake that struck near Magna March 18, a new poll shows that about half of Utah residents didn’t feel like they were prepared for that shaker.

The poll of 964 registered Utah voters taken by the Scott Rasmussen firm on behalf Deseret News and the University of Utah’s Hinckley Institute shows 45% of respondents felt they were prepared, 46% felt they weren’t and 9% remain unsure.

On top of that uncertainty, more people than not aren’t convinced state and local governments are prepared either, with 39% unsure about government preparedness, compared to 35% who said yes, government is ready for an earthquake, and 26% who say it isn’t.

The survey, done April 15-21, also asked residents what, if any action, they took afterward to prepare for future disasters, with the overwhelming majority buying supplies, at 58%, while 32% engaged in learning more about what to do in the event of an earthquake. A slight number of people, 2%, said they reinforced the masonry at their home.

The poll had a margin of error of plus/minus 3.2 percentage points.

“There are definitely some positive results there and some I am not surprised about. We realize it has been a long time since anyone in Utah has felt an earthquake of that size,” said Joe Dougherty, spokesman with the Utah Division of Emergency Management.

“It was clear this was a brand-new experience for many, many Utahns.”

He added he wasn’t surprised to learn half of Utah residents didn’t feel prepared because even though the state has a culture of preparedness, it can be strange to get ready for something that hasn’t happened for so long.

“When it does, that is when it puts your preparedness to the test,” he said. “Clearly we have always known Utah could improve its preparedness and this could be a catalyst for that.”

As to the slight majority of Utah residents who don’t think state and local governments are prepared for a natural disaster, Dougherty said that makes sense if people aren’t tracking what government response is in place.

“Someone is going to feel unsure of government preparedness if they are not aware of what government is doing,” he said. “Some of that is going to be on individuals to go out and find out what government is up to. I feel really confident about our preparedness, but I see it every day.”

He urged residents to go to and learn more about the state’s emergency response team that meets every month, involving coordination among state agencies and first responders.

Earlier this week, the Utah Geological Survey released a four-year study that provides new detailed mapping of faults along the Wasatch Front that are capable of surface rupture.

The survey said in a large earthquake, surface rupture could cause significant damage to homes, schools, businesses and other buildings along the Wasatch Front, as well as disrupt critical infrastructure.

Using high-resolution elevation surveys derived from laser sensors mounted on aircraft, researchers conducted the fault mapping and marked “special study zones” that will be essential planning tools for local governments when it comes to land use planning and regulation. The information will also be useful for potential homebuyers.

While Magna’s earthquake was considered moderate, the survey said faults in the area are capable of generating earthquakes as strong as magnitude 7.6 and releasing 700 times more energy, according to the survey.

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Any earthquake larger than about magnitude 6.5 can rupture the ground surface, producing fault scarps from a couple inches high to up to 20 feet high and 40 miles long on the Wasatch Front, researchers said.

“As a result of this research, we better understand where we’ve had surface-rupturing earthquakes in the geologic past, and where we may have them in the future. Knowing where fault scarps are present helps us make better land use decisions now and in the future,” said the survey’s hazards geologist Emily Kleber. “This new study provides detailed fault mapping and delineates special study zones for the Wasatch fault zone from southern Idaho to central Utah.”

The agency cautions that the mapping is not precise enough to safely locate specific buildings on individual lots, so ultimately government planners will have to use their own judgment when it comes to information provided in the special study zones.

The study was the result of a collaborative effort between the Utah Geological Survey and the U.S. Geological Survey. Along with new imagery, researchers used previous geologic mapping and looked at studies of ancient earthquakes and historical aerial photography, and did field investigations.

The study is available on the Utah Geological Survey’s website and also at the bookstore at the Utah Department of Natural Resources offices.