Scientists predict that within a 30-year period (beginning in 2014), there’s a 51 percent chance that the San Francisco region specifically will experience one or more magnitude-7.0 or greater earthquakes.These and several other major faults in the region are part of the San Andreas fault system and can cause damaging earthquakes, like the 1989 Loma Prieta earthquake. The Calaveras and Hayward faults extend up the east side of the San Francisco Bay.The main trace of the San Andreas fault runs through much of the State of California, including the Santa Cruz Mountains and up the San Francisco Peninsula, before heading offshore at Daly City and returning onshore again at Bolinas and continuing up the Marin and Sonoma County coasts.The greater San Francisco Bay Area has a high likelihood of future damaging earthquakes as it straddles the San Andreas fault system-the major geologic boundary between the North American and Pacific tectonic plates.What is the Earthquake Risk in San Francisco What to Expect from an Earthquake along the Hayward Fault Even moderate shaking can damage seismically-vulnerable structures and trigger landslides that could quickly block roads and highways.Īlameda, Contra Costa, Marin, Napa, San Francisco, San Mateo, Santa Clara, Solano, Sonoma
Scientists report that partial ruptures of the Cascadia Seismic Zone occurring on the southern half (which extends into Northern California) have historically generated earthquakes with magnitude 8 or greater.This zone is capable of generating an earthquake of a magnitude 9 or larger, occurring-on average-once every 500 years.The Cascadia Subduction Zone stretches underneath the Humboldt-Del Norte county region, extending from Cape Mendocino all the way up through the Pacific Northwest.