Style and rate of Holocene slip, Palos Verdes fault, southern California

Recent studies of the Palos Verdes fault in the Los Angeles Outer Harbor characterize the fault's Holocene activity. The studies included areal and local geophysical surveys, as well as drilling, sampling, and dating of the subsurface materials. The studies identify the fault's location in the shallow subsurface, document evidence of Holocene strike-slip, quantify dip-slip versus sediment age, and quantify the net slip where an early Holocene paleochannel crosses the fault. The slip rate for the Palos Verdes fault is constrained to between 2.7 and 3 mm/yr for the past 7.8 to 8 ka. Because the new evidence shows that the Palos Verdes fault has one of the highest slip rates in the Los Angeles basin, the studies provide significant new insight into the regional tectonics and the seismic risk of the Los Angeles region. Using this rate of slip and segmentation models for the fault, the coastal Los Angeles region can expect an MW 7 to 7.2 event about every 400 to 900 years from this potential seismic source.