A mysterious earthquake deep below northern Utah had scientists scratching their heads back in 1979. The rumble seemingly occurred far lower beneath the Earth’s crust than scientists had believed was possible.

The tremor may not have been particularly strong, at a magnitude of 3.8, but the recorded seismic data threw experts for a loop nonetheless. The data suggested the rumbling had occurred over 55 miles below sea level, a depth that made no sense in conventional geology.

“I did some other analysis that convinced me of the reality of the deep depth but it was hard to convince others of the highly anomalous mantle earthquake occurring in a region where none should exist,” said George Zandt, who was a University of Utah seismology researcher at the time and helped record the unusual quake, in a new statement.

Now, as detailed in a study published earlier this year in the journal The Seismic Record, University of Utah geology professor Keith Koper and Zandt — who came out of retirement for the new investigation — analyzed eight subsequent “deep earthquakes” in the region, confirming they occurred in the Earth’s upper mantle, dozens of miles below the boundary of the crust.

Koper and his colleagues say they’ve determined that the quakes are an “archetypal continental mantle event,” meaning they’re related to movements in the Earth’s mantle that take place over extremely long time scales.

The research highlights how much there’s still to learn about these forceful tectonic dynamics deep inside the planet, and how surprisingly different they are from more shallow, crust-based seismic events.

“It’s sort of a mystery in terms of fundamental physics,” Koper said in a statement. “How in the world can these things happen?”

“Another reason why it’s a big deal is that we have no idea how big they can be,” he added. “With crustal earthquakes, we can measure what we think their maximum size is going to be. We measure the faults that we can map out near the surface.”

Unlike earthquakes that occur in the Earth’s curst, deep earthquakes don’t announce themselves through foreshocks and aftershocks. The team determined they occur at the western edge of the Wyoming Craton — a leftover block of our planet’s lithosphere, the rigid outermost shell of the Earth, which stretches across northern Utah and southwest Wyoming — where temperatures can exceed 1,300 degrees Fahrenheit.

The team suspects these new “deep quakes” could be caused by the mantle slowly squeezing by the Wyoming Craton.

“On the scale of millions of years, the mantle is hitting the craton and then flowing around it,” Koper explained. “It’s that interaction where that mantle flow is being diverted around this hard cratonic root that’s causing the increased strain rate, the increased deformation and it’s also creating extra stresses.”

“We think it’s that interaction between the keel of the iceberg and the medium around it that’s leading to these earthquakes,” he added.

More on earthquakes: California Primed for Apocalyptic Earthquake, Geological Research Finds

HURRICANE, Utah (ABC4) — With Summer in full swing, more people are heading to Utah’s lakes and reservoirs to cool off. However, with more water-related deaths across the state this year, officials are reminding people that using a life jacket often makes the difference.

As temperatures climb, Sand Hollow State Park is filled with boaters, paddleboarders and swimmers looking to cool off. With more people hitting the water, natural resource officers are reminding visitors to know the rules and make safety a priority.

“This year is looking like one of the deadliest,” resource officer Chris Nelson told ABC4.com. “If you look back far enough, not so far ago, having five fatalities was a whole summer’s worth across multiple different fields of recreation, from hiking and search and rescue operations to OHV and boating, and we’re looking at that now just from boating, and it’s the beginning of June. Not a great start.”

“Every kid 12 and under does have to be wearing a life jacket at all times,” natural resource officer Chad Tarr added. “There needs to be a life jacket for everyone accounted on board of a paddle craft or a vessel at all times as well.”

For Rex Johnson, a local in Southern Utah, life jackets aren’t just for people. He and his wife visit Sand Hollow several times a week and ensure their two dogs wear jackets every time they hit the water, too.

“We were out here one day, and there were a lot of waves, and so she went after a Frisbee but couldn’t see it, and she just kept circling and circling, and it made me nervous. I didn’t know how long she could just circle, so we decided at that point to get them life jackets,” he recounted.

Johnson added that he wishes more people had the same approach. “What I noticed is the people that are out here on the stand up paddleboard, they rarely wear a life jacket. So that kind of makes me nervous,” he said.

Shelly Mackun teaches diving classes at Sand Hollow and said even the most experienced swimmers can find themselves in trouble in the water.

“You get out, and it’s a hundred degrees outside, and you jump in the water, and the water right now is about 74-ish. That’s considered cold water, and especially when your body is overheated, and you jump in, you’re likely to gasp, and as you do that, you’re going to swallow some water,” Mackun said.

She added, “I always have some flotation on because it’s not always just about you that other things can happen. You can get knocked in the head. You can buy a paddle from somebody paddleboarding. You can slip off your paddleboard and fall in the water, and again, that hot air temperature with the cold water temperature can be a deadly mix.”

State officials said that most of this year’s drowning victims were not wearing life jackets and hope more people will make them a normal part of their time on the water this Summer.

WASHINGTON TERRACE, Weber County — A new cemetery for military veterans, just the second in Utah, is coming to an undeveloped parcel in Washington Terrace, with work to start as early as next year.

“It’s a beautiful location for a cemetery. There’s some very big bluffs where the main cemetery will be built,” said Jeff Hanson, a deputy commissioner with the Utah Department of Veterans and Military Affairs who focuses on facilities. Expansion areas extend to lower bluffs, he said, “but the view is incredible.”

The first phase of the project along 5800 South west of South 500 East calls for roads, an administration building, a committal shelter, a flag plaza, columbarium walls for cremated remains and the initial crypt field. Design work is to be done by September, he said, and the first phase of the cemetery work will then be put out for bids.

Development could begin in 2027, he estimates, with the first phase work to take perhaps a year. A federal grant will cover the estimated $14 million price tag of the first phase, and the state will handle subsequent maintenance and upkeep.

The development is significant for veterans in Weber and Davis counties and the rest of northern Utah because it gives them a more feasible option for burial in a veterans cemetery. The only other state facility for veterans is the Utah State Veterans Cemetery and Memorial Park north of Camp Williams in Bluffdale while the only federal cemetery with open burial space is the Southern Utah National Cemetery in Cedar City.

“Having a veterans cemetery in northern Utah, veterans can consider that option, and it’s a good option because a veteran can receive a free plot and a free marker,” Hanson said. “Not only that, but it’s just going to be an extremely beautiful cemetery based on its location. … I think there’ll be a lot of interest for veterans to be interred at the facility.”

Beyond that, he said the facility, overlooking the Weber River and I-84 to the south, would be an apt location for Veterans Day and Memorial Day events, with the planned flag plaza expected to be able to accommodate around 200 people. The project area sits at the largely undeveloped southern end of Washington Terrace, across the Weber River from the northern end of Hill Air Force Base in adjacent Davis County.

The project has been in the works for years, and the 102-acre parcel of land for the cemetery was donated from a private landowner. Last week, the Washington Terrace City Council amended the zoning of the project area to allow for cemetery development. The parcel size allows for expansion in the years and decades to come.

“We think it’s a wonderful addition to our community and the region,” said Washington Terrace City Manager Tom Hanson. “We have all the confidence that it’ll be a wonderful neighbor and a benefit to the veterans, particularly in our area.”

Terry Schow, an advocate for veterans in northern Utah and the former executive director of the Utah Department of Veterans Affairs, before its name change, said there are around 18,000 military veterans living in Davis County and 17,000 or 18,000 in Weber County. Another 4,500 or so live in Box Elder and Cache counties more to the north.

“From a veteran standpoint, obviously we’re happy to have something up here in northern Utah. You got Hill Air Force Base up here, a lot of military people here,” he said.