Fig. 3: Spatiotemporal evolution of the maximum probability of unrest (Pun; or probability that a large-magnitude earthquake happens in 30 days or less) in Southern California.
From: Abnormal low-magnitude seismicity preceding large-magnitude earthquakes
Results obtained for a 6 months, b 2 months, and c 10 days before the first event of the 2019 Ridgecrest sequence (red star). Uncolored areas are unexplored locations, or locations with no earthquakes in the region and time interval of interest (see “Methods”). Black lines show the major fault lines of Southern California, Southwest Nevada, and Northwest Arizona (US Geological Survey’s interactive Quaternary faults database; https://doi.org/10.5066/F7S75FJM); and warm colors and red numbers highlight areas with anomalous low-magnitude seismicity. (1) Southern tip of San Joaquin Valley (e.g., unnamed fault zone, Mt. Poso fault). (2) Southern tip of San Joaquin Valley (Wheeler Ridge and Pleito fault zones). (3) California–Nevada–Arizona border region (Spotted Range, Mercury Ridge, West Pintwater Range, and Indian Springs Valley faults). (4) California–Nevada–Arizona border region (Las Vegas faults, e.g., Eglington and Frenchman Mountains faults). (5) California–Nevada–Arizona border region (small unnamed faults). (6) Southwest flank of Sierra Nevada mountains (e.g., Ken Canyon fault). (7) Epicentral area of Ridgecrest events (Southern Sierra Nevada, Little Lake, and Panamint Valley—southern section—fault zones). (8) Southern tip of San Joaquin Valley (Poso Creek, Edison, and other unnamed faults). (9) Antelope Valley (Lenwood–Lockhart, Mirage Valley, and Kramer Hills fault zones; Blake Ranch fault). (10) Antelope Valley (San Andreas fault—Mojave Section). (11) San Gabriel Mountains and Los Angeles County (San Gabriel and Sierra Madre fault zone, Los Angeles faults, Compton thrust fault, Palos Verdes fault zone). (12) Southern Channel Islands (San Pedro Basin fault, junction between San Diego Through fault and Catalina Fault zone). (13) California–Nevada–Arizona border region (Maynard Lake, Sheep Basin, Sheep-East Desert Ranges, Sheep Range, Kane Spring Wash, Wildcat Wash, Arrow Canyon Range, Carp Road, and California Wash faults). Geographical maps were created using MATLAB R2020b (Mapping Toolbox).
