Studies at the Southern California Earthquake Center (SCEC) are suggesting that postseismic deformation is significant and long lasting. This seems the case, at least, in a region whose dimension is comparable to the fault rupture length. Researchers at SCEC found strong spatial correlation between the high strain rates and the past large earthquakes at the epicentral areas of the 1952 Kern County, 1971 Imperial, and 1992 Landers earthquakes.
Southern California spans a plate boundary composed of hundreds of faults, major and minor, over a region hundreds of km wide. Measuring the crustal deformation field across this broad and complex plate boundary poses a great challenge. The Crustal Deformation Working Group of the SCEC orchestrated a major effort to provide, for the first time, a unified geodetic crustal deformation field covering southern California.