Utah needs a moderate earthquake, mild enough to cause only minimal damage but strong enough to shake complacent government officials, says the state's quake preparedness manager.

"What we need is an administrative earthquake of magnitude 5 (on the Richter scale)," James Tingey said Tuesday. "Magnitude 5 is right on the border between damage and no damage. Anything below that is just not useful for determining what an earthquake would do."The vibrations caused by such a temblor would help geologists and engineers determine which buildings and structures along the populous Wasatch Front are most prone to damage or failure.

Utah has had two such quakes within the past year, but they were in virtually uninhabited areas of Emery and Sevier counties.

"An administrative earthquake would not be a bad thing," Tingey told the Ogden chapter of the Society of Logistics Engineers.

He said it would help researchers learn more about the individual faults from Brigham City to southern Utah County, home to 83 percent of Utah's residents.

Based on Utah's history, he said, the Wasatch Front will have an earthquake in the 7.5 magnitude range, "a large, damaging quake" about every 350 years.

Hill Air Force Base will play a critical role in helping Utah recover from a major quake because the base's runway is in a geologically stable zone and should survive with relatively minor damage.

"There's a good chance, however, that Salt Lake International Airport will be knocked out," he said.

Hill also will provide urban search and rescue teams that can immediately fly to devastated areas. The chance of survival for people trapped inside collapsed buildings is 80 percent the first day, and then 10 percent thereafter, Tingey said.

Utah needs to have a team that can deploy rapidly and Hill has that ability, he said. The base, with an intact airport, also would be involved in the "massive problem" of funneling supplies to damage zones.

Getting state and local governments as organized will be more difficult, he said, adding, "I just don't see a whole lot of motivation on this."

It is hard to get people to spend a lot of money when they expect an earthquake only once every 350 years, Tingey said.

Utah is moving slowly but has made progress with the worst hazards, bringing 20 unreinforced buildings up to earthquake code this year alone, Tingey said.

"But 60 percent of the buildings along the Wasatch Front are of similar construction, held together by gravity. If we could build buildings out of giant Legos, we would really be safe."