It's because there are bigger faults in Caliifornia.Which is San andres which is 800 miles which cuts through California.We all know earth is contesntly changing, and earthquakes are apart of earth chaging.So every times the tictonic plates moves it causes California, and other states close by to aswell, but not as bad.
Southern California Earthquakes and Faults. The earthquakes of California are caused by the movement of huge blocks of the earth's crust- the Pacific and North American plates. ... Vertical faults such as the San Andreas (red band from top left to bottom right) are shown as a thin strip.
