Spatial variations in earthquake source characteristics within the 2011 Mw = 9.0 Tohoku, Japan rupture zone



[1] The great Mw = 9.0 2011 Tohoku earthquake appears to have complex rupture characteristics, with slower rupture velocity during the early portion of the rupture and spatial variations in the radiation frequency content. These spatial and temporal variations suggest that the subduction zone fault has spatially varying friction conditions that led to differences in the 2011 rupture characteristics, conditions that might also affect other earthquakes within the rupture zone. We find spatial variations for source parameters of 90 relocated earthquakes between 1992 and 2011 along northern Japan, with longer durations observed in shallow near trench events relative to shorter duration deeper events. A majority of these events do not lie within the high slip zone of 2011, however, and occur instead in the region of the 1896 tsunami earthquake to the north. We also find correlation between the longest duration event locations and low seismic velocities based on recent tomography models.