The rare Napa, CA quake sent a resounding message about seismic activity -- not only is it difficult to predict when it will occur, predicting where the earth will move is also an inexact science.

California's wine country residents received a reminder of the planet's penchant for random rage September 3 when slipping geological plates generated a 5.2 trembler on an undiscovered fault. The area hasn't been shaken or stirred by an earthquake in almost a century.

Because no other natural disaster strikes with so little warning -- in time or place -- a perpetual state of preparedness is crucial if you live in a region rife with fault lines.

Your home can be one of the safest places to weather a quake.

Wood-frame houses, when properly constructed, are designed to give and roll with a quake's punches.

But older homes, newer ones with deteriorating foundations and those with structures prone to seismic damage, can be a disaster waiting to happen -- without a moment's notice.

If you retrofit your home to better withstand the forces of a quake, not only will you improve its ability to withstand the forces of an earthquake, but you could also be eligible for special construction loans and grants as well as reduced insurance rates.

Earthquake power strikes a home in two ways: with thrusting, lateral or side-to-side motion and with rocking, rolling, uplifting action. The combination can literally throw a home off its foundation.

Bolt it down

To protect against lateral and uplifting movement, your home's framing should be bolted to its foundation.

If your home was built after 1950, there's a good chance it's bolted down, thanks to building codes. Still, it may require some strengthening if it has experienced termite or moisture damage that may have weakened the connections.

If you aren't sure if your home is bolted to its foundation, crawl, stoop or walk under your home and take a peek. If it doesn't have a crawl space, look at the foundation connections in your garage, utility closet or other room with unfinished wall framing.

Otherwise, you may have to remove a portion of the dry wall to inspect. If it's bolted in the garage, it's likely the rest of the home is bolted.

Framing is typically bolted to the foundation at the sill, the lowest point in the wood frame. Engineers recommend expansion bolts fastened into the sill plate at intervals of six feet or less.

Also, "hold downs" (heavy metal brackets) can be bolted to the ends of structural wall framing to protect against uplifting energy.

Where you can't reach areas to bolt the foundation, you can use foundation brackets and anchors nailed to the mud sill and then bolted to the side of the foundation.

Cripple walls

To further protect against lateral movement, shore up unsupported cripple walls. Also called "pony" walls, the structure sits between the first floor and the foundation and generally surrounds a large crawl space, basement or garage. It should be reinforced with shear walls -- plywood properly installed on the inside, to prevent the wall from buckling and folding over on its foundation.

Hardware and retrofitting plans are available for attaching the first floor to the foundation and the cripple wall as well as for fastening together multiple stories, shoring up "soft story" construction (decks, garages and other open areas beneath closed in areas) and pier construction.

Chimneys and masonry

The inherent rigidity of chimneys, masonry walls and larger masonry structures -- such as homes in the New Madrid Fault region in the Middle South -- makes them more susceptible to seismic-related damage. Such structures, however, require the expertise of a mason or other knowledgeable contractor to inspect and retrofit, often with re-bar and other metal-laden materials.

Any structural strengthening requires building permits and it is prudent to choose a licensed contractor experienced in seismic retrofitting.

Keep documentation of the project to show future buyers. You may have to disclose the work, which often helps increase the value of your home.

Quake resources

Published: September 7, 2000

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Broderick Perkins parlayed a career in old-school journalism into a contemporary digital news service that really hits home. The award-winning consumer journalist, originally from Wilmington, DE, is founder, publisher and executive editor of the bootstrap DeadlineNews Group, a Silicon Valley-based editorial content and consulting service specializing in residential real estate, consumer news and related editorial consulting services. The DeadlineNews Group includes the website, DeadlineNews.com, offering real estate editorial content and consulting services, and its back shop, the Deadline Newsroom, an open house on news that really hits home. Perkins obtained his formal journalism education from University of Delaware and a journalism boot camp, the Institute of Journalism Education at the University of California-Berkeley. He went on to 20 years of service as a daily newspaper journalist at the Wilmington, DE News Journal and San Jose, CA Mercury News. Perkins covered housing on the San Jose Mercury News reporting team which earned a General News Reporting Pulitzer Prize in 1989 for coverage of the Loma Prieta earthquake. He has also produced real estate, consumer and small business content for the Wall Street Journal, Los Angeles Times, RealtyTimes.com, Nolo.com, Better Homes and Gardens, the National Association of Realtors, Homestore/Move and Intuit/Quicken among more than three dozen publications. In addition to managing the DeadlineNews Group, Perkins most recently served as chief editorial consultant for Nolo's Essential Guide To Buying Your First Home, Nolo, and writes real estate television scripts for RealtyTimes.com.