SAN FRANCISCO, UNITED STATES
Vulnerability map
The San Francisco Bay Area is located in the midst of a network of faults on the North American edge of the Pacific Ring of Fire (an extensive series of seismically active areas featuring volcanoes, plate movements, and oceanic trenches). The most notable of these faults is the San Andreas Fault, which is the source of regular seismic activity along California’s coast.
San Francisco experienced major earthquakes in 1865 and 1868, but the 7.8 magnitude 1906 earthquake and resulting fires were particularly shocking and formative, lingering in the city’s cultural consciousness. Even so, building standards fell far behind risk factors until the 1970s.
In Seismic City, Joanna Dyl attempts to explain the slowness of this process, an elaboration that seems equally relevant to Seattle:
“Disaster remained something understood as removed from everyday life, and even when major earthquakes struck the city—most notably in 1906 but also in 1865, 1868, and even 1989—residents emphasized restoring the normal over explicit adaptation that would have required altering practices of urban development.”
She quotes sociologist Kai Erikson, saying that “one of the crucial tasks of culture...is to help people camouflage the actual risks of the world around them--to help them edit reality in such a way that it seems manageable,... [so] that the dangers pressing in on them from all sides are screened out of their line of vision as they go about their everyday rounds.” The seismic culture of San Francisco, as described by Dyl, was largely one of denial until the late twentieth century, when it shifted into one of action.
The 1989 Loma Prieta quake led to the passage in 1992 of an ordinance mandating upgrades of unreinforced masonry buildings. The program was largely successful, and the city moved on to address other hazards, enacting the Mandatory Soft Story Retrofit Program in 2013. Next up to be addressed is likely unreinforced or non-ductile concrete buildings, which are highly risky but difficult to identify without a structural inspection.
San Francisco has a rich cultural history and has prioritized historic preservation, even in the face of intense economic pressures. Historic resource surveys evaluate buildings for significance and integrity, and identify relevant context, themes, and periods of significance. However, conservation districts are found only in the downtown core. The Mills Act provides property tax savings for the preservation of historic resources.
