We're not as stable as we think

EARTHQUAKE!!!

Now that I have your attention, here's where we, uh, stand:

Odds of a major event happening somewhere in Utah in the next 50 years: 1 in 3.

Odds of a major event happening along the Wasatch Front in the next 50 years: 1 in 5.

Odds of a major event happening along the Wasatch Fault in the next 50 years : 1 in 8.

Odds of a major event happening along the Salt Lake segment of the Wasatch Fault in the next 50 years: 1 in 12.

The definition of a "major event" is an earthquake that registers 6.5 or higher on the Richter Scale. In layman terms, that means anything strong enough to actually cause a fault to break the surface of the ground.

These numbers come courtesy of Bob Carey, earthquake program manager for the state of Utah, and Walter Arabasz, director of the University of Utah seismograph stations, two extremely nice men whose job it is to keep us abreast of the bad news.

We're not as stable as we think.

Like it or not, earthquakes happen. There is plenty of geologic evidence that they have been happening in what is now known as Utah for thousands of years, and will continue happening.

While it is hardly Utah's only earthquake zone, the most famous, or infamous, is the Wasatch Fault, a shelf of potential instability 235 miles long that starts just across the Idaho border in Malad and ends in the small town of Fayette in central Utah. The Wasatch Fault is divided into five distinct segments. The "Salt Lake segment" between North Salt Lake and Draper gets the most attention because it is the most populated.

Geologists have determined that any single segment of the Wasatch Fault gets a significant earthquake, on average, every 1,400 years. The last major event on the Salt Lake segment was approximately 1,300 years ago. Statistically, then, Salt Lake is due.

"But earthquakes don't come along at regular intervals like they're on a conveyor belt," cautions Arabasz. "They are not uniformly spaced."

Proof of that is the Wasatch Fault segment between Brigham City and north Ogden. There hasn't been a major event there for 2,200 years. The Brigham City segment, in baseball terms, is in a slump of Chicago Cubs proportion. It isn't due, it's overdue.

"If you had to go into the earthquake-prediction business, which we stay out of, that would be the one you'd say is most likely to occur," says Carey. "The other segments of the fault have all kind of caught up to each other, except that one."