SAN FRANCISCO (AP) — San Francisco port officials say it could cost between $2 billion and $3 billion to secure three miles of seawall underlying the Embarcadero waterfront and prevent it from causing significant damage in the event of a major earthquake.
The Port of San Francisco released the estimate in a report last week.
The report states most of the seawall is built over weak marine clay that tends to amplify earthquake shaking, and that fill used to create land behind the seawall is subject to liquefaction, a phenomenon in which soil loses strength and behaves like a liquid.
The report finds that a moderate to major earthquake would probably push the seawall out toward San Francisco Bay, anywhere from up to a foot to several feet. The seawall protects a memorable stretch of San Francisco’s waterfront from Fisherman’s Wharf to AT&T Park, which is heavy with tourists, commuters and joggers.
The stretch also includes the popular Ferry Building, which survived the 1989 Loma Prieta Earthquake, but the epicenter of that quake was 60 miles away. The magnitude of that quake was 6.9.
A working group of the United States Geological Survey concluded a 72 percent probability of a strong earthquake occurring in the region in a 30-year period between 2014 and 2043.