SANTA CRUZ, Calif. (KION) With last night’s 3.9 earthquakes in San Francisco and last week’s Condo Collapse in Florida, can Santa Cruz survive a strong earthquake?
The answer is complicated but according to the City of Santa Cruz Local Mitigation Hazard Plan, the city is a high seismic risk. It's within 15 miles of at least six major faults and fault systems. The highest threat is the San Andreas Fault that passes through the Santa Cruz Mountains and is 12 miles from the city's downtown.
The two most destructive earthquakes in Santa Cruz were in 1989 and 1906. Several buildings downtown were rebuilt after the 1989 Loma Prieta Earthquake, which left $6 billion in damages and killed 62 people, three in the city of Santa Cruz. The other was 1906 San Francisco earthquake that almost destroyed that Santa Cruz Courthouse.
The most intense damage happened in liquefaction areas where buildings and other structures were built on top of loose, water-saturated soils. Liquefaction happens is when a strong movement like an earthquake creates space in the soil that allows water to penetrate through it, creating something like quicksand. On the map below, you’ll see that the entire downtown city of Santa Cruz is at risk of liquefaction.
"In the last, probably, 20 years, we've become a little more sophisticated as far as requiring more than code design for their buildings. However, we don't have the mandate to require more than code right now," said John McLucas, the Senior Plans Examiner for the City of Santa Cruz.
As far as diminishing the risk of liquefaction, there's no code mandate to go in and retrofit any existing building. According to McLucas, the current requirement is a life safety code, which is intended to make sure people can escape the building.
According to a U.S Geological Survey, there's a 62% probability of at least one magnitude 6.7 or greater quake, that could cause serious damage in the San Francisco Bay region (including Santa Cruz) before 2032.