Magazine article Sunset

Learning from the Big Quake, Getting Ready for the Future

Magazine article Sunset

Learning from the Big Quake, Getting Ready for the Future

Article excerpt

Learning from the big quake, getting ready for the future On October 17, northern California again learned first-hand how devastating an earthquake can be. Even though many of us are still experiencing the tragedy of the 7.1 quake theat rocked the San Francisco and Monterey Bay areas, that grim event does offer us a fresh opportunity to study how a major temblor affects our houses and communities.

One thing we learned immediately was the capacity of groups and individuals to help when needed. Crews worked around the clock to clear roads and restore power, while disater aid groups provided medical help, food, clothing, and shelter to earthquake victims. Volunteers were invaluable--directing traffic, pitching in at shelters, helping the stranded and injured.

Private and corporate donations of money and goods poured into relief agencies.

Soon after the quake, Sunset editors were inspecting damaged houses, meeting with geologists, engineers, and public officials. We wanted to find out what happened in order to help our reader be better prepared next time.

Which houses held up,

which didn't? How could we

have been better prepared?

It's heartening to see that modern building codes are working: most houses built after the 1930s survived with relatively minor or no damage.

There were exceptions. Some houses that were poorly built or on steep or unstable ground suffered regardless of their age. Chimneys and other unreinforced masonry proved particularly vulnerable, collapsing at new and old homes alike.

Older homes throughout the quake zone demonstrated clear patterns of failure. We can learn from these failures--as well as from some successful methods of coping and recovering.

Porches fell off. When supports shook loose, older porches inadequately tied to houses yanked free, their roofs crashing down. Beefing up structural ties might have save these tacked-on appendages.

Cripple walls moved. Many older houses rest on cripple walls (short 2-by-4 walls between foundation and first floor). As the ground moved, cripple walls buckled or tipped, and houses simply dropped to their knees. This might have been avoided if the cripple walls had been sheathed with plywood and if framing was free of termites and dry rot. Also., sill plates should have been bolted to foundations.

Chimneys gave way. Bricks rained down as chimneys crumbled--sometimes falling away from the house, sometimes crashing through the roof. Some chimneys could have been strengthened with steel and concrete, then braced to stabilize them and control where they might fall. …

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