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Earthquake readiness tips for 2010
It’s the resolution season: the time of year for gym promotions, salon coupons and the general swearing off of holiday excess. But while you look to help yourself start over in the New Year, don’t forget about your home – which could need more of a makeover than meets the eye. And with Wednesday’s 5.8 earthquake along the California-Mexico border, the element of surprise most quakes bring is not one for which you want to be ill-prepared.
Local experts released a report earlier this year identifying thousands of residential buildings in the city that a major quake could render unlivable – and that was just based on a partial survey. And with seismologists saying that there’s a 63 percent chance the Bay Area will suffer a powerful earthquake within the next 30 years, there is a need to act soon to remedy the problem.
Tip #1: Know your situation
Tip #2: Keep an eye on City Hall
Tip #3: Make an emergency plan
This 1989 photograph, taken in San Francisco's Marina district, shows a soft-story apartment building severely damaged by the Loma Prieta earthquake. Photo courtesy of NISEE-UC Berkeley.
Toby Engelberg, a volunteer with one of The Big Rumble events held simultaneously around the Bay on Oct. 17 – the 20th anniversary of the Loma Prieta quake – answers questions and gives away manuals, customizable emergency booklets, maps and need to know information on what to do when an earthquake occurs. Photo courtesy of Vivian Morales/The Public Press.
Seismically vulnerable building types
The San Francisco Planning and Urban Research Association – SPUR, a nonprofit policy think tank– has noted several categories of seismically vulnerable buildings in the city. Here are descriptions of some of the most common:
- Soft-story buildings typically predate the 1970s and have large open spaces, such as garages or commercial space, on the first floor. They are concentrated in neighborhoods such as the Marina, North Beach, Mission, Western Addition, Richmond and Pacific Heights.
- Unreinforced masonry buildings have one or more “bearing” walls made of brick. They are typically old buildings, common in Chinatown and South of Market neighborhoods. Significant progress has been made upgrading unreinforced masonry buildings since the city ordered retrofits to about 2,000 of them in the early 1990s. More than 90 percent of those have been reinforced in the years since, according to the Department of Building Inspection.
- Non-ductile concrete buildings are dangerous for their brittle concrete pillar support, which can fail suddenly and completely in an earthquake. A ductile building, on the other hand, is able to deform heavily during an earthquake without collapsing – think of stretching versus snapping. The Concrete Coalition, a volunteer network affiliated with the Oakland-based Earthquake Engineering Research Institute, is creating a statewide database of non-ductile concrete buildings and developing strategies to fix them.
Aside from residential structures, SPUR also is looking into the earthquake resilience of buildings that house social service organizations, which residents would count on to provide vital shelter or food services following an earthquake. “If the city is relying on them, then they have to think about [their safety] too,” said David Bonowitz, a structural engineer and consultant for the Concrete Coalition and a member of the SPUR task force.