Geophysical properties and seismotectonics of the Tohoku forearc region

► We show 3-D images of six physical parameters under the Tohoku forearc. ► The 2011 Tohoku earthquake occurred in a big high-V zone near the trench. ► Seismogenesis of the megathrust zone is affected by structural heterogeneities. ► Subducted seamounts and ridges may form asperities in the megathrust zone.