Earthquakes Along the San Andreas Fault Zone, for Example, Are

Earthquakes along the San Andreas fault zone, for example, are repetitive-they reoccur in roughly the same regions over and over again-separated by decades or centuries because_______ .

A) stress continues to build up all the time and when it is great enough to overcome friction there will be an earthquake and then the process will start over again
B) faults are always moving or creeping so an earthquake will occur whenever two sides meet that have the right properties for an earthquake
C) plate boundaries move at regular rates so the interactions across plate boundaries are predictable and regular
D) there are areas that are weak and always break when small amounts of energy are applied to them