Minor tremor felt in northern Utah

Many northern Utahns felt the shake of a minor quake on Monday.

The 3.4 earthquake struck eight miles underground at a location eight miles northeast of Morgan and 20 miles east-southeast of Ogden. "The shock was reported felt along the Wasatch Front urban corridor between Ogden and northern Salt Lake City," said Walter J. Arabasz, director of the University of Utah Seismograph Stations.

The temblor struck at 11:15 a.m. By late afternoon, 123 reports had come in to an earthquake tracking site from people in Bountiful, Centerville, Clearfield, Croydon, Farmington, Kaysville, Layton, Morgan, Roy, Sandy, Salt Lake City and Ogden.

Anyone who felt the earthquake is invited to fill out a survey form at the stations' Web site, www.quake.utah.edu, Arabasz said.

Instruments allowed the earth scientists to calculate how far below the surface the shift occurred. "We have a depth of about eight miles," he said. "It's a normal earthquake in that region."

Ground shaking amounted to only 0.003 to 0.009 the force of gravity, "above the threshold of human perception but well below the threshold of damage," he added.

He did not know of any mapped fault in the area that would be associated with the earthquake. The quake did not originate in the Wasatch Fault, an infamous earthquake fault line stretching along much of the state.

Instead, deformation beneath the Wasatch Front mountains may be involved in the latest little earthquake. That deformation is "related to the long-term uplift of the Wasatch Range," he said.

Because the quake was under the Wasatch Range, the energy propagating westward was perceptible at the surface.

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