I just found this at a web site I was reading on the Hecotr Quake:
"Scientifically, the interesting thing about the Hector Mine quake is that it
began in an area where the Landers earthquake of 28 June 1992 had
increased stress in the Earth's crust. A similar area of increased stress
occurred on the other side of the Landers quake—on the great San Andreas
fault system. According to modeling done at the University of Nevada Reno,
the Hector Mine quake seems to have added further to that stress. "

• The textbook earthquake