More than any other U.S. city, San Francisco is known for major earthquakes, most famously the 1906 quake that caused a fire that destroyed much of the city. Later research into the earthquake led to the discovery of the San Andreas Fault. Frisco remains at high risk for a big one: Between now and 2032, there's a 62 percent chance of a quake stronger than 6.6 on the Richter scale.