Biographer Clarice Stasz and others believe London 's father was astrologer William Chaney . Flora Wellman was living with Chaney in San Francisco when she became pregnant . Whether Wellman and Chaney were legally married is unknown . Most San Francisco civil records were destroyed by the extensive fires that followed the 1906 earthquake ; nobody knows what name appeared on her son 's birth certificate . Stasz notes that in his memoirs , Chaney refers to London 's mother Flora Wellman as having been his " wife " ; he also cites an advertisement in which Flora called herself " Florence Wellman Chaney "
1906 earthquake
1906 San Francisco earthquake
Jack London