Concern #2: Could a large earthquake create a tsunami and what effect could that have on the Bay Area?
The largest earthquake recorded in the Bay Area was on the San Andreas Fault in 1906. Even though this fault lies right outside the Golden Gate, there is little evidence that it caused a tsunami of notable size. This, again, is due to the nature of strike-slip fault zones.
The Pacific Northwest, however, sits above a subduction zone where one crust slab is dipping beneath the North American continent. Movement in this area of great enough magnitude could not only trigger a quake on the San Andreas Fault, but it would also release a tsunami roughly eighty feet tall. This giant wall of water would reach the Bay Area and cause damage around the coast. It is not, however, an event of the gravest concern for Californians as a temblor of that size isn’t predicted to occur for another 200 years.
