Nation Is ‘The Big One’ coming? A California fault capable of a 8.0 earthquake is moving for the first time, study says October 17, 2019 Kristin Lam, USA TODAY Comments Off on Is ‘The Big One’ coming? A California fault capable of a 8.0 earthquake is moving for the first time, study says A California fault that could produce a 8.0-magnitude earthquake began sliding following a series of July temblors, according to a new study.