He said some problems, such as downed lines or conductors being knocked down, "can be repaired in fairly reasonable amounts of time, depending on locations and the kinds of ground shaking."

Eskelsen said in 2006 that one advantage locally is that "all our major sources of generation are off the Wasatch Front," mainly coming from coal-burning plants in central Utah and Wyoming. So earthquakes along the Wasatch Front are not likely to damage them.

He said Utah Power does have a few smaller generating plants along the Wasatch Front, but they are used mainly for voltage regulation and providing extra peak-period power. He said ground shaking would trip circuit breakers and shut them down initially, and it could take some time to restart them.

Eskelsen said Utah Power often has exercises on how to handle such emergencies and also has plans in place to bring in workers from other states to help handle any large-scale disaster.

Carey, with state emergency services, says many people do not realize what such an extended power outage may really mean.

For example, he said credit cards could not be used because card readers need power, as do ATM machines.

He said people should keep an emergency supply of cash because of that. But he added that some stores might not be able to sell supplies anyway, because they rely on bar code readers for all pricing, and readers may not have power for extended periods. This is one reason emergency supplies of food have long been suggested.

Also, without power, blowers for furnaces would not work, gas stations cannot pump gasoline, electric stoves will not cook, many phones (such as those that have answering machines and have an extra power plug for them) will not ring, and traffic signals will not work.

For such reasons, emergency officials had long suggested such things as Utahns always keeping gas tanks in cars at least half full and having a supply of fuel — including perhaps a camp stove and propane to allow cooking.

Natural gas

State projections back in 2006 did not specifically forecast how many residents would lose natural gas service in a 7.0 quake, or how long it would take to restore it. But they did predict about 2,000 breaks in gas pipelines.

Darren Shepherd, spokesman for Questar, said in 2006 that the company felt its network would perform fairly well in a 7.0 quake. He noted that the company had replaced most of its old, brittle cast iron pipes in the 1990s, and newer piping was designed better to survive ground shaking.