Four seismicity holes, several of which correspond to megathrusts that struck more than 250 years ago. The lack of Cascadia seismicity (left panel) has been attributed by others to complete healing and locking of the megathrust (Obana et al. 2014), we believe it could instead be in a post-mainshock shutdown. Sites of megathrusts or very large earthquakes in 1765 and 1762 also appear today as holes (middle and right panels).