The 1906 San Francisco earthquake struck the city on April 18 and caused widespread devastation. The 7.8-8.25 magnitude quake caused extreme shaking for only a minute but fires started and raged for three days, destroying much of the city. Liquefaction and aftershocks killed many people in the following hours and days. Primary and secondary seismic waves were involved, with the secondary waves causing more violent shaking after the initial jolt.

1. San Francisco Earthquake Of 1906 By Rodolfo Brandon Bernardino