(2) Two Antique Color Postcards of the 1906 San Francisco Earthquake. Published by Hearst's Boston Sunday American. Undivided back, unused. Condition: These are original antique postcards, not a copy or reproduction. They are in good to very good condition. Comments: The 1906 San Francisco earthquake was caused by a slip of the San Andreas Fault over a segment about 275 miles long, and shock waves could be felt from southern Oregon down to Los Angeles. San Francisco's brick buildings and wooden Victorian structures were especially devastated.