Upper-plate controls on co-seismic slip in the 2011 magnitude 9.0 Tohoku-oki earthquake

Residual topography and gravity anomalies reveal a tectonic boundary in northeast Japan, which is proposed to represent the offshore continuation of the Median Tectonic Line; the contrast in frictional properties across this structure may control earthquake behaviour there, as recently demonstrated by the giant 2011 Tohoku-oki earthquake.