By Jason A. Givens

December 12, 2006 | RICHMOND -- The experts don't know when it's coming, but they all agree Utah is overdue for a big earthquake.

Utah is ranked No. 9 on the United States Geological Survey's top 10 states for earthquakes. However, that doesn't mean the state has a lot of big earthquakes like California, but it does have about 700 smaller ones every year. In fact according to the USGS Web site a small quake hit Cache Valley a little over a week ago. While last week's earthquake was small and probably not felt by anyone, scientists say a larger earthquake could strike the valley.

Crone said the potential magnitude of earthquakes in this region is high 6s to low 7s, which he said is high enough to be a cause for concern to people in the valley. He said the Wasatch Front also has active faults, and earthquakes from that region could cause damage in Cache Valley.

The most damaging earthquake to hit Cache Valley happened Aug. 30, 1962; its magnitude was 5.7. Richmond was the quake's epicenter, but it also caused significant damage in Franklin, Lewiston, Logan and Preston, Idaho. The earthquake caused an estimated $1 million damage and Cache County was declared a disaster region by the Small Business Administration.

Richmond was the area that sustained the most damage. Richard Bagley, who was 32 years old at the time, recalls the loud rumbling sound the earthquake made. "It wasn't really just that you felt it, you heard it as well," he said. "It was quite an unnerving thing."

Bagley, who was a teacher at North Cache High School, said the earthquake damaged the school, toppled headstones in the cemetery, destroyed several of the older homes and damaged the LDS Benson Stake Tabernacle to the point where it had to be torn down.

"It's such a helpless feeling," he said of his experience during the earthquake. "You're wondering, 'What will be the end result?' It was really a miracle that no one got (seriously) physically injured."

Earthquakes have the potential to cause damage in several ways. James Bay and Loren Anderson, professors in USU's civil engineering department have studied earthquakes extensively and helped map areas of concern for the USGS. One of the areas in which they have done significant research is liquefaction.

The Utah Geological Survey Web site says liquefaction can occur when sandy soils saturated with water are subjected to ground shaking caused by an earthquake. The soil essentially liquefies and loses strength and acts like quicksand rather than solid ground. The outcome can cause extreme devastation, buildings can sink into the ground or tilt, empty buried tanks may rise to the surface, slopes can fail and several other potentially hazardous events may occur.

Bay said liquefaction is quite common with larger earthquakes and is a major cause for concern. He added liquefaction occurred in the 1962 Cache Valley earthquake.

The Utah Geological Survey Web site points out that liquefaction is a major hazard with earthquakes in Utah and has been responsible for significant damage in several earthquakes around the world. The valleys along the Wasatch Front have a high vulnerability to liquefaction due to susceptible soils, shallow ground water and a relatively high probability of moderate to large earthquakes.

While liquefaction could be very damaging, Anderson said the greatest damage would come from ground shaking due to the large number of unreinforced masonry buildings (typically brick buildings built before 1960).

In the event of an earthquake the University of Utah Seismograph Stations' Web site says the safest place to be is in an open field where nothing can fall on you. "Earthquakes do not injure or kill people; buildings and falling objects do," the Web site says. The site recommends if you are indoors, immediately take cover under a table or sturdy piece of furniture. Do not attempt to run out of the building or use stairs or an elevator.

Anderson recommends doing an inspection of your home to locate potential hazards. Some of the things you can do are anchor items such as large bookshelves and water heaters to the wall, so they will not tip over and cause injury. He added it is also a good idea to remove objects near cribs that could fall and injure babies.

As to when the next big earthquake will hit, Bay said, "If it is going to happen this year or in the next 300 years, we really can't tell."

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