89 quake: Wake-up call for Bay Area buildings



Five people died when the Loma Prieta earthquake shook the bricks right off one building on San Francisco's Bluxome Street. Town after town saw buildings crumble in the quake.

"It started raining concrete," one woman recalled. "They pushed the door in so we could get out and lift us out over the roof. We didn't know the roof had crumbled in."

27,000 buildings were damaged or destroyed. A few years later, the devastating Northridge earthquake hit Southern California, followed soon after by a huge quake in Kobe, Japan.

"That cluster of events really forced the engineering community to look at the damage, to understand the kinds of failures that took place and significantly changed the building codes," says UC Berkeley professor Mary Comerio.

State and local regulations forced improvements to many brick buildings, but they make up just one percent of Bay Area buildings. For other building types, the new codes are a major step forward, but there is one critical element missing.

"Those only apply to new buildings. You know the majority of our buildings are older," Comerio points out.

Some older buildings have been retrofitted, mostly public buildings like some on the UC Berkeley campus and the city halls in Oakland and San Francisco. When it comes to privately-owned buildings, homes and apartments especially, very few people have taken action.

"I think most people given the choice would rather have a granite kitchen than retrofit their home, even though intellectually they know in the long term that would probably be a better investment," says Mary Lou Zoback, Ph.D.

She adds that it is a tough psychology to get around. Zoback spent 20 years with the U.S. Geological Survey and now works for a company that helps insurance companies calculate risk. She says the biggest lesson from the Loma Prieta earthquake is the danger of what are called soft-story buildings -- two, three and four-story buildings with garages on the first floor that simply collapsed.

"Because that ground floor is very open, it can support the weight of the building but as soon as you start shaking it laterally ... that first floor can't support the moving building and it collapses," Zoback says.

Not every soft-story building is at equal risk. Only an engineer can tell for sure. Buildings with parking underneath have been built for decades in many styles all over the Bay Area. So far, there are no requirements that they be retrofitted.

Comerio says, "The more time goes by when we haven't had an earthquake, there's a kind of it won't happen on my watch mentality."

Written and produced by Jennifer Olney

Web exclusive content commemorating the 20th anniversary of the 1989 Loma Prieta quake. Includes extended interviews with reporters who covered the quake, as well as city officials and first responders who lived through it all.

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