Aftershock patterns and main shock faulting

We have compared aftershock patterns following several moderate to large earthquakes with the corresponding distributions of coseismic slip obtained from previous analyses of the recorded strong ground motion and teleseismic waveforms. Well-located aftershock hypocenters are projected onto the main shock fault plane, and their positions are examined relative to the zones of coseismic displacement indicated by the estimated distributions of main shock slip. We also examine the aftershock focal mechanisms, when these data are available, in an attempt to identify possible patterns of secondary faulting within the aftershock zone.