 In balancing these various factors it also provides an estimate of how much seismicity is not accounted for in the fault model, possibly in faults not yet discovered.The amount of slip occurring on unidentified faults has been estimated at between 5 and about 20 mm/yr depending on the location (generally higher in the LA area) and deformation model, with one model reaching 30 mm/yr just north of LA.While UCERF3 represents a considerable improvement over UCERF2, and the best available science to-date for estimating California's earthquake hazard, the authors caution that it remains an approximation of the natural system.