An earthquake is Mother Nature’s most horrifying threat to Redwood City which sits on saturated granular sediment that will liquify if the ground shakes.
It is also considerably more defenseless against fires, floods and landslides than other natural disasters because of its coastal location and topography, according to the local hazard mitigation report the City Council recently approved to send to FEMA.
Now, FEMA has to approve the analysis so Redwood City can secure money for prevention.
“It opens up the gates for projects,” said fire Battalion Chief Dan Pucci, who was part of a team that has been collecting the data since September. “We don’t have any plans or projects we’re sitting on. ... It just put grant money on its way.”
But the 72-page report explains that risk severity and probability of a major earthquake are both highly unlike any other natural disaster because the city sits about 2,000 feet away from the San Andreas fault on top of loose, saturated, fine-grain soils.
It is especially jarring since the U.S. Geological Survey estimates there is a 63 percent chance for a magnitude-6.7 or greater quake in the Bay Area in the next 30 years.
“Redwood City was effectively a port when it was built. That means it was on a slough,” said USGS geophysicist Jack Boatwright. “It’s really gorgeous, but if it’s shaken too strongly, we don’t know what’s going to happen.”
Boatwright also said Redwood City doesn’t stick out in his mind as the most vulnerable.
“It would be a mistake to try to figure out which city is the worst off or even rank them ... but our concern is first and foremost the Peninsula and the San Andreas Fault,” he said.
Fires, floods and landslides are less-serious threats, according to the report, and could be triggered by a major earthquake, but damage prevention could be cheaper than retrofitting entire buildings.
Ready to rumble
Below are estimates of damage based on 2005 market values for vulnerable systems only affected by the equivalent of the 1906 earthquake and not subsequent aftermath such as fires.
Residential buildings: $11,001,000,000
Commercial buildings: $2,970,000,000
Industrial buildings: $813,000,000
City Hall: $11,237,046
Police Department: $13,804,080
Water system: $59,912,251
Storm drain and sewer systems: $16,510,486
Community activities building: $2,215,413
Source: Hazardous mitigation report