 UCERF3 was prepared by the "Working Group on California Earthquake Probabilities" (WGCEP), a collaboration between the United States Geological Survey (USGS), the California Geological Survey (CGS), and the Southern California Earthquake Center (SCEC), with significant funding from the California Earthquake Authority (CEA).A major achievement of UCERF3 is use of a new methodology that can model multifault ruptures such as have been observed in recent earthquakes.This allows seismicity to be distributed in a more realistic manner, which has corrected a problem with prior studies that overpredicted earthquakes of moderate size (between magnitude 6.5 and 7.0).