The Big Bear earthquake happened east of Los Angeles , and 3 hours 26 minutes after the M 7.3 1992 Landers earthquake occurred 22 miles ( 35 km ) to the east . The Big Bear earthquake was first believed to be an aftershock of the Landers quake . However , the United States Geological Survey determined that this was a separate , but related , earthquake . These two earthquakes are considered a regional earthquake sequence , rather than a main shock and aftershock . They were part of a complex pattern of regional stress adjustment that also led to the 1999 Hector Mine earthquake
1992 Landers earthquake
1992 Landers earthquake
1992 Big Bear earthquake