Strain rate over Southern California determined from geodetic measurements50 (grey shading). Active faults from the USGS database51 (https://earthquake.usgs.gov/hazards/qfaults/). Surface ruptures (red shading) of recent M > 7 earthquakes in Southern California since 1850 (https://earthquake.usgs.gov/hazards/qfaults/citation.php). The 1800 M7.3 rupture is from Salisbury et al52, the 1812 M7.1 rupture is from Lozos53, the 1812 M7.5 rupture is from Toppozada and Branum54, The 1892 M7.2 rupture is from Rockwell et al.55. Yellow box outlines the footprint of Fig. 2.