The fault was identified in 1895 by Professor Andrew Lawson of UC Berkeley , who discovered the northern zone . It is often described as having been named after San Andreas Lake , a small body of water that was formed in a valley between the two plates . However , according to some of his reports from 1895 and 1908 , Lawson actually named it after the surrounding San Andreas Valley . Following the 1906 San Francisco earthquake , Lawson concluded that the fault extended all the way into southern California
1906 San Francisco earthquake
1906 San Francisco earthquake
San Andreas Fault