Salt Lake residents face a tough decision next spring - a decision that involves their pocketbooks in a big way and the potential safety of their children.

A few days ago, the Salt Lake Board of Education unanimously moved to let voters decide whether the district should embark on a $100 million effort to earthquake-proof its 35 schools over the next 20-25 years.The bottom line for voters will be deciding whether Salt Lake City's earthquake potential and the safety risk it poses for schoolchildren, justify the substantial, long-term boost in property taxes - about $60 annually for a $100,000 home - needed to finance a pay-as-you-go program.

Improvements are planned in two phases, with the high schools coming first, followed by intermediate schools and the two most hazardous elementary schools over the first 10 years. The remaining elementary schools would be dealt with in phase two.

The 1989 San Francisco-area earthquake and a spate of earthquake predictions that followed have increased public concerns about earthquake preparedness.

A seismic study for the Salt Lake School District has added to local concerns to the point the board finds itself in a difficult and unenviable position.

On one hand is the simple question of legal liability and responsibility. The board could opt for the easy argument that because schools have passed state-required safety and fire inspections, the district has done all that is legally required.

But there is also the complex issue of moral responsibility. That issue is not easily resolved.

With seismic experts constantly reminding Salt Lakers that "The Big One" (as they say in California) is on its way sometime within the next 50 years, the question becomes whether such projections obligate those charged with educating students to take on extraordinary responsibility - and the attendant costs.

The board wants taxpayers to make that decision and will ask voters to go to the polls sometime before May 2 to make their wishes known. That should give officials time to include the tax hike in the 1991-92 budget if voters approve the plan.

The pay-as-you-go approach significantly lowers costs over bonding and, officials say, is feasible because of the time needed to complete the program. The logistics involved in housing students during the improvement process make it impossible for more than one project to be handled at a time. Officials believe money from the tax hike will accumulate faster than it will be expended.

Though state law gives the district power to levy the tax without a referendum vote, it's only sensible that the public should be directly involved in deciding a matter involving so much money and so many lives.

One final point: If voters reject the plan, it will be hard for the public to blame education officials in case of major damage to Salt Lake City schools from a big earthquake.